From dfd0afbf151d85411b371e841f62b81ee5d1ca54 Mon Sep 17 00:00:00 2001 From: David Michael Date: Sun, 13 Nov 2022 15:52:17 -0500 Subject: [PATCH 001/101] libbpf: Fix uninitialized warning in btf_dump_dump_type_data MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit GCC 11.3.0 fails to compile btf_dump.c due to the following error, which seems to originate in btf_dump_struct_data where the returned value would be uninitialized if btf_vlen returns zero. btf_dump.c: In function ‘btf_dump_dump_type_data’: btf_dump.c:2363:12: error: ‘err’ may be used uninitialized in this function [-Werror=maybe-uninitialized] 2363 | if (err < 0) | ^ Fixes: 920d16af9b42 ("libbpf: BTF dumper support for typed data") Signed-off-by: David Michael Signed-off-by: Daniel Borkmann Acked-by: Stanislav Fomichev Acked-by: Alan Maguire Link: https://lore.kernel.org/bpf/87zgcu60hq.fsf@gmail.com --- tools/lib/bpf/btf_dump.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index 12f7039e0ab2..e9f849d82124 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -1989,7 +1989,7 @@ static int btf_dump_struct_data(struct btf_dump *d, { const struct btf_member *m = btf_members(t); __u16 n = btf_vlen(t); - int i, err; + int i, err = 0; /* note that we increment depth before calling btf_dump_print() below; * this is intentional. btf_dump_data_newline() will not print a From e662c7753668bbfb95e25043c6064088cc3a996d Mon Sep 17 00:00:00 2001 From: Maryam Tahhan Date: Sun, 13 Nov 2022 05:33:27 -0500 Subject: [PATCH 002/101] bpf, docs: Fixup cpumap sphinx >= 3.1 warning Fixup bpf_map_update_elem() declaration to use a single line. Reported-by: Akira Yokosawa Signed-off-by: Maryam Tahhan Signed-off-by: Daniel Borkmann Tested-by: Akira Yokosawa Acked-by: Stanislav Fomichev Link: https://lore.kernel.org/bpf/20221113103327.3287482-1-mtahhan@redhat.com --- Documentation/bpf/map_cpumap.rst | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/Documentation/bpf/map_cpumap.rst b/Documentation/bpf/map_cpumap.rst index eaf57b38cafd..61a797a86342 100644 --- a/Documentation/bpf/map_cpumap.rst +++ b/Documentation/bpf/map_cpumap.rst @@ -48,8 +48,7 @@ Userspace program will result in the program failing to load and a verifier warning. .. c:function:: - int bpf_map_update_elem(int fd, const void *key, const void *value, - __u64 flags); + int bpf_map_update_elem(int fd, const void *key, const void *value, __u64 flags); CPU entries can be added or updated using the ``bpf_map_update_elem()`` helper. This helper replaces existing elements atomically. The ``value`` parameter From c7694ac340b0394afba079fc3d1072f4c99bcfc9 Mon Sep 17 00:00:00 2001 From: Kang Minchul Date: Mon, 14 Nov 2022 04:06:46 +0900 Subject: [PATCH 003/101] libbpf: checkpatch: Fixed code alignments in btf.c Fixed some checkpatch issues in btf.c Signed-off-by: Kang Minchul Signed-off-by: Andrii Nakryiko Acked-by: Stanislav Fomichev Link: https://lore.kernel.org/bpf/20221113190648.38556-2-tegongkang@gmail.com --- tools/lib/bpf/btf.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 3bd812bf88ff..71e165b09ed5 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -1724,7 +1724,8 @@ err_out: memset(btf->strs_data + old_strs_len, 0, btf->hdr->str_len - old_strs_len); /* and now restore original strings section size; types data size - * wasn't modified, so doesn't need restoring, see big comment above */ + * wasn't modified, so doesn't need restoring, see big comment above + */ btf->hdr->str_len = old_strs_len; hashmap__free(p.str_off_map); @@ -2329,7 +2330,7 @@ int btf__add_restrict(struct btf *btf, int ref_type_id) */ int btf__add_type_tag(struct btf *btf, const char *value, int ref_type_id) { - if (!value|| !value[0]) + if (!value || !value[0]) return libbpf_err(-EINVAL); return btf_add_ref_kind(btf, BTF_KIND_TYPE_TAG, value, ref_type_id); From e3ba8e4e8c19a9b4d1866bc72d81afb10c043560 Mon Sep 17 00:00:00 2001 From: Kang Minchul Date: Mon, 14 Nov 2022 04:06:47 +0900 Subject: [PATCH 004/101] libbpf: Fixed various checkpatch issues in libbpf.c Fixed following checkpatch issues: WARNING: Block comments use a trailing */ on a separate line + * other BPF program's BTF object */ WARNING: Possible repeated word: 'be' + * name. This is important to be be able to find corresponding BTF ERROR: switch and case should be at the same indent + switch (ext->kcfg.sz) { + case 1: *(__u8 *)ext_val = value; break; + case 2: *(__u16 *)ext_val = value; break; + case 4: *(__u32 *)ext_val = value; break; + case 8: *(__u64 *)ext_val = value; break; + default: ERROR: trailing statements should be on next line + case 1: *(__u8 *)ext_val = value; break; ERROR: trailing statements should be on next line + case 2: *(__u16 *)ext_val = value; break; ERROR: trailing statements should be on next line + case 4: *(__u32 *)ext_val = value; break; ERROR: trailing statements should be on next line + case 8: *(__u64 *)ext_val = value; break; ERROR: code indent should use tabs where possible + }$ WARNING: please, no spaces at the start of a line + }$ WARNING: Block comments use a trailing */ on a separate line + * for faster search */ ERROR: code indent should use tabs where possible +^I^I^I^I^I^I &ext->kcfg.is_signed);$ WARNING: braces {} are not necessary for single statement blocks + if (err) { + return err; + } ERROR: code indent should use tabs where possible +^I^I^I^I sizeof(*obj->btf_modules), obj->btf_module_cnt + 1);$ Signed-off-by: Kang Minchul Signed-off-by: Andrii Nakryiko Acked-by: Stanislav Fomichev Link: https://lore.kernel.org/bpf/20221113190648.38556-3-tegongkang@gmail.com --- tools/lib/bpf/libbpf.c | 45 ++++++++++++++++++++++++++---------------- 1 file changed, 28 insertions(+), 17 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 1d263885d635..b5df6aca06ea 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -347,7 +347,8 @@ enum sec_def_flags { SEC_ATTACHABLE = 2, SEC_ATTACHABLE_OPT = SEC_ATTACHABLE | SEC_EXP_ATTACH_OPT, /* attachment target is specified through BTF ID in either kernel or - * other BPF program's BTF object */ + * other BPF program's BTF object + */ SEC_ATTACH_BTF = 4, /* BPF program type allows sleeping/blocking in kernel */ SEC_SLEEPABLE = 8, @@ -488,7 +489,7 @@ struct bpf_map { char *name; /* real_name is defined for special internal maps (.rodata*, * .data*, .bss, .kconfig) and preserves their original ELF section - * name. This is important to be be able to find corresponding BTF + * name. This is important to be able to find corresponding BTF * DATASEC information. */ char *real_name; @@ -1863,12 +1864,20 @@ static int set_kcfg_value_num(struct extern_desc *ext, void *ext_val, return -ERANGE; } switch (ext->kcfg.sz) { - case 1: *(__u8 *)ext_val = value; break; - case 2: *(__u16 *)ext_val = value; break; - case 4: *(__u32 *)ext_val = value; break; - case 8: *(__u64 *)ext_val = value; break; - default: - return -EINVAL; + case 1: + *(__u8 *)ext_val = value; + break; + case 2: + *(__u16 *)ext_val = value; + break; + case 4: + *(__u32 *)ext_val = value; + break; + case 8: + *(__u64 *)ext_val = value; + break; + default: + return -EINVAL; } ext->is_set = true; return 0; @@ -2770,7 +2779,7 @@ static int bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf) m->type = enum64_placeholder_id; m->offset = 0; } - } + } } return 0; @@ -3518,7 +3527,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj) } /* sort BPF programs by section name and in-section instruction offset - * for faster search */ + * for faster search + */ if (obj->nr_programs) qsort(obj->programs, obj->nr_programs, sizeof(*obj->programs), cmp_progs); @@ -3817,7 +3827,7 @@ static int bpf_object__collect_externs(struct bpf_object *obj) return -EINVAL; } ext->kcfg.type = find_kcfg_type(obj->btf, t->type, - &ext->kcfg.is_signed); + &ext->kcfg.is_signed); if (ext->kcfg.type == KCFG_UNKNOWN) { pr_warn("extern (kcfg) '%s': type is unsupported\n", ext_name); return -ENOTSUP; @@ -4965,9 +4975,9 @@ bpf_object__reuse_map(struct bpf_map *map) err = bpf_map__reuse_fd(map, pin_fd); close(pin_fd); - if (err) { + if (err) return err; - } + map->pinned = true; pr_debug("reused pinned map at '%s'\n", map->pin_path); @@ -5485,7 +5495,7 @@ static int load_module_btfs(struct bpf_object *obj) } err = libbpf_ensure_mem((void **)&obj->btf_modules, &obj->btf_module_cap, - sizeof(*obj->btf_modules), obj->btf_module_cnt + 1); + sizeof(*obj->btf_modules), obj->btf_module_cnt + 1); if (err) goto err_out; @@ -6237,7 +6247,8 @@ bpf_object__reloc_code(struct bpf_object *obj, struct bpf_program *main_prog, * prog; each main prog can have a different set of * subprograms appended (potentially in different order as * well), so position of any subprog can be different for - * different main programs */ + * different main programs + */ insn->imm = subprog->sub_insn_off - (prog->sub_insn_off + insn_idx) - 1; pr_debug("prog '%s': insn #%zu relocated, imm %d points to subprog '%s' (now at %zu offset)\n", @@ -10995,7 +11006,7 @@ struct bpf_link *bpf_program__attach_usdt(const struct bpf_program *prog, usdt_cookie = OPTS_GET(opts, usdt_cookie, 0); link = usdt_manager_attach_usdt(obj->usdt_man, prog, pid, binary_path, - usdt_provider, usdt_name, usdt_cookie); + usdt_provider, usdt_name, usdt_cookie); err = libbpf_get_error(link); if (err) return libbpf_err_ptr(err); @@ -12304,7 +12315,7 @@ int bpf_object__open_subskeleton(struct bpf_object_subskeleton *s) btf = bpf_object__btf(s->obj); if (!btf) { pr_warn("subskeletons require BTF at runtime (object %s)\n", - bpf_object__name(s->obj)); + bpf_object__name(s->obj)); return libbpf_err(-errno); } From b486d19a0ab097eecf3ee679369b216d2cb6c34e Mon Sep 17 00:00:00 2001 From: Kang Minchul Date: Mon, 14 Nov 2022 04:06:48 +0900 Subject: [PATCH 005/101] libbpf: checkpatch: Fixed code alignments in ringbuf.c Fixed some checkpatch issues in ringbuf.c Signed-off-by: Kang Minchul Signed-off-by: Andrii Nakryiko Acked-by: Stanislav Fomichev Link: https://lore.kernel.org/bpf/20221113190648.38556-4-tegongkang@gmail.com --- tools/lib/bpf/ringbuf.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c index d285171d4b69..51808c5f0014 100644 --- a/tools/lib/bpf/ringbuf.c +++ b/tools/lib/bpf/ringbuf.c @@ -128,7 +128,7 @@ int ring_buffer__add(struct ring_buffer *rb, int map_fd, /* Map read-only producer page and data pages. We map twice as big * data size to allow simple reading of samples that wrap around the * end of a ring buffer. See kernel implementation for details. - * */ + */ tmp = mmap(NULL, rb->page_size + 2 * info.max_entries, PROT_READ, MAP_SHARED, map_fd, rb->page_size); if (tmp == MAP_FAILED) { @@ -220,7 +220,7 @@ static inline int roundup_len(__u32 len) return (len + 7) / 8 * 8; } -static int64_t ringbuf_process_ring(struct ring* r) +static int64_t ringbuf_process_ring(struct ring *r) { int *len_ptr, len, err; /* 64-bit to avoid overflow in case of extreme application behavior */ From 1f6d52f1a8947436dc5b2575e2fffb831f240141 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Tue, 15 Nov 2022 00:45:22 +0530 Subject: [PATCH 006/101] bpf: Remove local kptr references in documentation We don't want to commit to a specific name for these. Simply call them allocated objects coming from bpf_obj_new, which is completely clear in itself. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221114191547.1694267-2-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- Documentation/bpf/bpf_design_QA.rst | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/Documentation/bpf/bpf_design_QA.rst b/Documentation/bpf/bpf_design_QA.rst index 17e774d96c5e..cec2371173d7 100644 --- a/Documentation/bpf/bpf_design_QA.rst +++ b/Documentation/bpf/bpf_design_QA.rst @@ -332,13 +332,14 @@ avoid defining types with 'bpf\_' prefix to not be broken in future releases. In other words, no backwards compatibility is guaranteed if one using a type in BTF with 'bpf\_' prefix. -Q: What is the compatibility story for special BPF types in local kptrs? ------------------------------------------------------------------------- -Q: Same as above, but for local kptrs (i.e. pointers to objects allocated using -bpf_obj_new for user defined structures). Will the kernel preserve backwards +Q: What is the compatibility story for special BPF types in allocated objects? +------------------------------------------------------------------------------ +Q: Same as above, but for allocated objects (i.e. objects allocated using +bpf_obj_new for user defined types). Will the kernel preserve backwards compatibility for these features? A: NO. Unlike map value types, there are no stability guarantees for this case. The -whole local kptr API itself is unstable (since it is exposed through kfuncs). +whole API to work with allocated objects and any support for special fields +inside them is unstable (since it is exposed through kfuncs). From 2d577252579b3efb9e934b68948a2edfa9920110 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Tue, 15 Nov 2022 00:45:23 +0530 Subject: [PATCH 007/101] bpf: Remove BPF_MAP_OFF_ARR_MAX In f71b2f64177a ("bpf: Refactor map->off_arr handling"), map->off_arr was refactored to be btf_field_offs. The number of field offsets is equal to maximum possible fields limited by BTF_FIELDS_MAX. Hence, reuse BTF_FIELDS_MAX as spin_lock and timer no longer are to be handled specially for offset sorting, fix the comment, and remove incorrect WARN_ON as its rec->cnt can never exceed this value. The reason to keep separate constant was the it was always more 2 more than total kptrs. This is no longer the case. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221114191547.1694267-3-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/linux/bpf.h | 9 ++++----- kernel/bpf/btf.c | 2 +- 2 files changed, 5 insertions(+), 6 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 798aec816970..1a66a1df1af1 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -165,9 +165,8 @@ struct bpf_map_ops { }; enum { - /* Support at most 8 pointers in a BTF type */ - BTF_FIELDS_MAX = 10, - BPF_MAP_OFF_ARR_MAX = BTF_FIELDS_MAX, + /* Support at most 10 fields in a BTF type */ + BTF_FIELDS_MAX = 10, }; enum btf_field_type { @@ -203,8 +202,8 @@ struct btf_record { struct btf_field_offs { u32 cnt; - u32 field_off[BPF_MAP_OFF_ARR_MAX]; - u8 field_sz[BPF_MAP_OFF_ARR_MAX]; + u32 field_off[BTF_FIELDS_MAX]; + u8 field_sz[BTF_FIELDS_MAX]; }; struct bpf_map { diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 5579ff3a5b54..12361d7b2498 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -3584,7 +3584,7 @@ struct btf_field_offs *btf_parse_field_offs(struct btf_record *rec) u8 *sz; BUILD_BUG_ON(ARRAY_SIZE(foffs->field_off) != ARRAY_SIZE(foffs->field_sz)); - if (IS_ERR_OR_NULL(rec) || WARN_ON_ONCE(rec->cnt > sizeof(foffs->field_off))) + if (IS_ERR_OR_NULL(rec)) return NULL; foffs = kzalloc(sizeof(*foffs), GFP_KERNEL | __GFP_NOWARN); From e5feed0f64f73e167ef70755d3dc2db959d8fd5c Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Tue, 15 Nov 2022 00:45:24 +0530 Subject: [PATCH 008/101] bpf: Fix copy_map_value, zero_map_value The current offset needs to also skip over the already copied region in addition to the size of the next field. This case manifests where there are gaps between adjacent special fields. It was observed that for a map value with size 48, having fields at: off: 0, 16, 32 size: 4, 16, 16 The current code does: memcpy(dst + 0, src + 0, 0) memcpy(dst + 4, src + 4, 12) memcpy(dst + 20, src + 20, 12) memcpy(dst + 36, src + 36, 12) With the fix, it is done correctly as: memcpy(dst + 0, src + 0, 0) memcpy(dst + 4, src + 4, 12) memcpy(dst + 32, src + 32, 0) memcpy(dst + 48, src + 48, 0) Fixes: 4d7d7f69f4b1 ("bpf: Adapt copy_map_value for multiple offset case") Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221114191547.1694267-4-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/linux/bpf.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 1a66a1df1af1..f08eb2d27de0 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -360,7 +360,7 @@ static inline void bpf_obj_memcpy(struct btf_field_offs *foffs, u32 sz = next_off - curr_off; memcpy(dst + curr_off, src + curr_off, sz); - curr_off += foffs->field_sz[i]; + curr_off += foffs->field_sz[i] + sz; } memcpy(dst + curr_off, src + curr_off, size - curr_off); } @@ -390,7 +390,7 @@ static inline void bpf_obj_memzero(struct btf_field_offs *foffs, void *dst, u32 u32 sz = next_off - curr_off; memset(dst + curr_off, 0, sz); - curr_off += foffs->field_sz[i]; + curr_off += foffs->field_sz[i] + sz; } memset(dst + curr_off, 0, size - curr_off); } From f0c5941ff5b255413d31425bb327c2aec3625673 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Tue, 15 Nov 2022 00:45:25 +0530 Subject: [PATCH 009/101] bpf: Support bpf_list_head in map values Add the support on the map side to parse, recognize, verify, and build metadata table for a new special field of the type struct bpf_list_head. To parameterize the bpf_list_head for a certain value type and the list_node member it will accept in that value type, we use BTF declaration tags. The definition of bpf_list_head in a map value will be done as follows: struct foo { struct bpf_list_node node; int data; }; struct map_value { struct bpf_list_head head __contains(foo, node); }; Then, the bpf_list_head only allows adding to the list 'head' using the bpf_list_node 'node' for the type struct foo. The 'contains' annotation is a BTF declaration tag composed of four parts, "contains:name:node" where the name is then used to look up the type in the map BTF, with its kind hardcoded to BTF_KIND_STRUCT during the lookup. The node defines name of the member in this type that has the type struct bpf_list_node, which is actually used for linking into the linked list. For now, 'kind' part is hardcoded as struct. This allows building intrusive linked lists in BPF, using container_of to obtain pointer to entry, while being completely type safe from the perspective of the verifier. The verifier knows exactly the type of the nodes, and knows that list helpers return that type at some fixed offset where the bpf_list_node member used for this list exists. The verifier also uses this information to disallow adding types that are not accepted by a certain list. For now, no elements can be added to such lists. Support for that is coming in future patches, hence draining and freeing items is done with a TODO that will be resolved in a future patch. Note that the bpf_list_head_free function moves the list out to a local variable under the lock and releases it, doing the actual draining of the list items outside the lock. While this helps with not holding the lock for too long pessimizing other concurrent list operations, it is also necessary for deadlock prevention: unless every function called in the critical section would be notrace, a fentry/fexit program could attach and call bpf_map_update_elem again on the map, leading to the same lock being acquired if the key matches and lead to a deadlock. While this requires some special effort on part of the BPF programmer to trigger and is highly unlikely to occur in practice, it is always better if we can avoid such a condition. While notrace would prevent this, doing the draining outside the lock has advantages of its own, hence it is used to also fix the deadlock related problem. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221114191547.1694267-5-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/linux/bpf.h | 17 ++++ include/uapi/linux/bpf.h | 10 +++ kernel/bpf/btf.c | 145 ++++++++++++++++++++++++++++++++- kernel/bpf/helpers.c | 32 ++++++++ kernel/bpf/syscall.c | 22 ++++- kernel/bpf/verifier.c | 7 ++ tools/include/uapi/linux/bpf.h | 10 +++ 7 files changed, 239 insertions(+), 4 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index f08eb2d27de0..05f98e9e5c48 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -175,6 +175,7 @@ enum btf_field_type { BPF_KPTR_UNREF = (1 << 2), BPF_KPTR_REF = (1 << 3), BPF_KPTR = BPF_KPTR_UNREF | BPF_KPTR_REF, + BPF_LIST_HEAD = (1 << 4), }; struct btf_field_kptr { @@ -184,11 +185,18 @@ struct btf_field_kptr { u32 btf_id; }; +struct btf_field_list_head { + struct btf *btf; + u32 value_btf_id; + u32 node_offset; +}; + struct btf_field { u32 offset; enum btf_field_type type; union { struct btf_field_kptr kptr; + struct btf_field_list_head list_head; }; }; @@ -266,6 +274,8 @@ static inline const char *btf_field_type_name(enum btf_field_type type) case BPF_KPTR_UNREF: case BPF_KPTR_REF: return "kptr"; + case BPF_LIST_HEAD: + return "bpf_list_head"; default: WARN_ON_ONCE(1); return "unknown"; @@ -282,6 +292,8 @@ static inline u32 btf_field_type_size(enum btf_field_type type) case BPF_KPTR_UNREF: case BPF_KPTR_REF: return sizeof(u64); + case BPF_LIST_HEAD: + return sizeof(struct bpf_list_head); default: WARN_ON_ONCE(1); return 0; @@ -298,6 +310,8 @@ static inline u32 btf_field_type_align(enum btf_field_type type) case BPF_KPTR_UNREF: case BPF_KPTR_REF: return __alignof__(u64); + case BPF_LIST_HEAD: + return __alignof__(struct bpf_list_head); default: WARN_ON_ONCE(1); return 0; @@ -403,6 +417,9 @@ static inline void zero_map_value(struct bpf_map *map, void *dst) void copy_map_value_locked(struct bpf_map *map, void *dst, void *src, bool lock_src); void bpf_timer_cancel_and_free(void *timer); +void bpf_list_head_free(const struct btf_field *field, void *list_head, + struct bpf_spin_lock *spin_lock); + int bpf_obj_name_cpy(char *dst, const char *src, unsigned int size); struct bpf_offload_dev; diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index fb4c911d2a03..6580448e9f77 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -6888,6 +6888,16 @@ struct bpf_dynptr { __u64 :64; } __attribute__((aligned(8))); +struct bpf_list_head { + __u64 :64; + __u64 :64; +} __attribute__((aligned(8))); + +struct bpf_list_node { + __u64 :64; + __u64 :64; +} __attribute__((aligned(8))); + struct bpf_sysctl { __u32 write; /* Sysctl is being read (= 0) or written (= 1). * Allows 1,2,4-byte read, but no write. diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 12361d7b2498..c0d73d71c539 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -3205,9 +3205,15 @@ enum { struct btf_field_info { enum btf_field_type type; u32 off; - struct { - u32 type_id; - } kptr; + union { + struct { + u32 type_id; + } kptr; + struct { + const char *node_name; + u32 value_btf_id; + } list_head; + }; }; static int btf_find_struct(const struct btf *btf, const struct btf_type *t, @@ -3261,6 +3267,63 @@ static int btf_find_kptr(const struct btf *btf, const struct btf_type *t, return BTF_FIELD_FOUND; } +static const char *btf_find_decl_tag_value(const struct btf *btf, + const struct btf_type *pt, + int comp_idx, const char *tag_key) +{ + int i; + + for (i = 1; i < btf_nr_types(btf); i++) { + const struct btf_type *t = btf_type_by_id(btf, i); + int len = strlen(tag_key); + + if (!btf_type_is_decl_tag(t)) + continue; + if (pt != btf_type_by_id(btf, t->type) || + btf_type_decl_tag(t)->component_idx != comp_idx) + continue; + if (strncmp(__btf_name_by_offset(btf, t->name_off), tag_key, len)) + continue; + return __btf_name_by_offset(btf, t->name_off) + len; + } + return NULL; +} + +static int btf_find_list_head(const struct btf *btf, const struct btf_type *pt, + const struct btf_type *t, int comp_idx, + u32 off, int sz, struct btf_field_info *info) +{ + const char *value_type; + const char *list_node; + s32 id; + + if (!__btf_type_is_struct(t)) + return BTF_FIELD_IGNORE; + if (t->size != sz) + return BTF_FIELD_IGNORE; + value_type = btf_find_decl_tag_value(btf, pt, comp_idx, "contains:"); + if (!value_type) + return -EINVAL; + list_node = strstr(value_type, ":"); + if (!list_node) + return -EINVAL; + value_type = kstrndup(value_type, list_node - value_type, GFP_KERNEL | __GFP_NOWARN); + if (!value_type) + return -ENOMEM; + id = btf_find_by_name_kind(btf, value_type, BTF_KIND_STRUCT); + kfree(value_type); + if (id < 0) + return id; + list_node++; + if (str_is_empty(list_node)) + return -EINVAL; + info->type = BPF_LIST_HEAD; + info->off = off; + info->list_head.value_btf_id = id; + info->list_head.node_name = list_node; + return BTF_FIELD_FOUND; +} + static int btf_get_field_type(const char *name, u32 field_mask, u32 *seen_mask, int *align, int *sz) { @@ -3284,6 +3347,12 @@ static int btf_get_field_type(const char *name, u32 field_mask, u32 *seen_mask, goto end; } } + if (field_mask & BPF_LIST_HEAD) { + if (!strcmp(name, "bpf_list_head")) { + type = BPF_LIST_HEAD; + goto end; + } + } /* Only return BPF_KPTR when all other types with matchable names fail */ if (field_mask & BPF_KPTR) { type = BPF_KPTR_REF; @@ -3339,6 +3408,12 @@ static int btf_find_struct_field(const struct btf *btf, if (ret < 0) return ret; break; + case BPF_LIST_HEAD: + ret = btf_find_list_head(btf, t, member_type, i, off, sz, + idx < info_cnt ? &info[idx] : &tmp); + if (ret < 0) + return ret; + break; default: return -EFAULT; } @@ -3393,6 +3468,12 @@ static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t, if (ret < 0) return ret; break; + case BPF_LIST_HEAD: + ret = btf_find_list_head(btf, var, var_type, -1, off, sz, + idx < info_cnt ? &info[idx] : &tmp); + if (ret < 0) + return ret; + break; default: return -EFAULT; } @@ -3491,11 +3572,52 @@ end_btf: return ret; } +static int btf_parse_list_head(const struct btf *btf, struct btf_field *field, + struct btf_field_info *info) +{ + const struct btf_type *t, *n = NULL; + const struct btf_member *member; + u32 offset; + int i; + + t = btf_type_by_id(btf, info->list_head.value_btf_id); + /* We've already checked that value_btf_id is a struct type. We + * just need to figure out the offset of the list_node, and + * verify its type. + */ + for_each_member(i, t, member) { + if (strcmp(info->list_head.node_name, __btf_name_by_offset(btf, member->name_off))) + continue; + /* Invalid BTF, two members with same name */ + if (n) + return -EINVAL; + n = btf_type_by_id(btf, member->type); + if (!__btf_type_is_struct(n)) + return -EINVAL; + if (strcmp("bpf_list_node", __btf_name_by_offset(btf, n->name_off))) + return -EINVAL; + offset = __btf_member_bit_offset(n, member); + if (offset % 8) + return -EINVAL; + offset /= 8; + if (offset % __alignof__(struct bpf_list_node)) + return -EINVAL; + + field->list_head.btf = (struct btf *)btf; + field->list_head.value_btf_id = info->list_head.value_btf_id; + field->list_head.node_offset = offset; + } + if (!n) + return -ENOENT; + return 0; +} + struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type *t, u32 field_mask, u32 value_size) { struct btf_field_info info_arr[BTF_FIELDS_MAX]; struct btf_record *rec; + u32 next_off = 0; int ret, i, cnt; ret = btf_find_field(btf, t, field_mask, info_arr, ARRAY_SIZE(info_arr)); @@ -3517,6 +3639,11 @@ struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type ret = -EFAULT; goto end; } + if (info_arr[i].off < next_off) { + ret = -EEXIST; + goto end; + } + next_off = info_arr[i].off + btf_field_type_size(info_arr[i].type); rec->field_mask |= info_arr[i].type; rec->fields[i].offset = info_arr[i].off; @@ -3539,12 +3666,24 @@ struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type if (ret < 0) goto end; break; + case BPF_LIST_HEAD: + ret = btf_parse_list_head(btf, &rec->fields[i], &info_arr[i]); + if (ret < 0) + goto end; + break; default: ret = -EFAULT; goto end; } rec->cnt++; } + + /* bpf_list_head requires bpf_spin_lock */ + if (btf_record_has_field(rec, BPF_LIST_HEAD) && rec->spin_lock_off < 0) { + ret = -EINVAL; + goto end; + } + return rec; end: btf_record_free(rec); diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 283f55bbeb70..7bc71995f17c 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1706,6 +1706,38 @@ bpf_base_func_proto(enum bpf_func_id func_id) } } +void bpf_list_head_free(const struct btf_field *field, void *list_head, + struct bpf_spin_lock *spin_lock) +{ + struct list_head *head = list_head, *orig_head = list_head; + + BUILD_BUG_ON(sizeof(struct list_head) > sizeof(struct bpf_list_head)); + BUILD_BUG_ON(__alignof__(struct list_head) > __alignof__(struct bpf_list_head)); + + /* Do the actual list draining outside the lock to not hold the lock for + * too long, and also prevent deadlocks if tracing programs end up + * executing on entry/exit of functions called inside the critical + * section, and end up doing map ops that call bpf_list_head_free for + * the same map value again. + */ + __bpf_spin_lock_irqsave(spin_lock); + if (!head->next || list_empty(head)) + goto unlock; + head = head->next; +unlock: + INIT_LIST_HEAD(orig_head); + __bpf_spin_unlock_irqrestore(spin_lock); + + while (head != orig_head) { + void *obj = head; + + obj -= field->list_head.node_offset; + head = head->next; + /* TODO: Rework later */ + kfree(obj); + } +} + BTF_SET8_START(tracing_btf_ids) #ifdef CONFIG_KEXEC_CORE BTF_ID_FLAGS(func, crash_kexec, KF_DESTRUCTIVE) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 85532d301124..fdbae52f463f 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -536,6 +536,9 @@ void btf_record_free(struct btf_record *rec) module_put(rec->fields[i].kptr.module); btf_put(rec->fields[i].kptr.btf); break; + case BPF_LIST_HEAD: + /* Nothing to release for bpf_list_head */ + break; default: WARN_ON_ONCE(1); continue; @@ -578,6 +581,9 @@ struct btf_record *btf_record_dup(const struct btf_record *rec) goto free; } break; + case BPF_LIST_HEAD: + /* Nothing to acquire for bpf_list_head */ + break; default: ret = -EFAULT; WARN_ON_ONCE(1); @@ -637,6 +643,11 @@ void bpf_obj_free_fields(const struct btf_record *rec, void *obj) case BPF_KPTR_REF: field->kptr.dtor((void *)xchg((unsigned long *)field_ptr, 0)); break; + case BPF_LIST_HEAD: + if (WARN_ON_ONCE(rec->spin_lock_off < 0)) + continue; + bpf_list_head_free(field, field_ptr, obj + rec->spin_lock_off); + break; default: WARN_ON_ONCE(1); continue; @@ -965,7 +976,8 @@ static int map_check_btf(struct bpf_map *map, const struct btf *btf, if (!value_type || value_size != map->value_size) return -EINVAL; - map->record = btf_parse_fields(btf, value_type, BPF_SPIN_LOCK | BPF_TIMER | BPF_KPTR, + map->record = btf_parse_fields(btf, value_type, + BPF_SPIN_LOCK | BPF_TIMER | BPF_KPTR | BPF_LIST_HEAD, map->value_size); if (!IS_ERR_OR_NULL(map->record)) { int i; @@ -1012,6 +1024,14 @@ static int map_check_btf(struct bpf_map *map, const struct btf *btf, goto free_map_tab; } break; + case BPF_LIST_HEAD: + if (map->map_type != BPF_MAP_TYPE_HASH && + map->map_type != BPF_MAP_TYPE_LRU_HASH && + map->map_type != BPF_MAP_TYPE_ARRAY) { + ret = -EOPNOTSUPP; + goto free_map_tab; + } + break; default: /* Fail if map_type checks are missing for a field type */ ret = -EOPNOTSUPP; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 07c0259dfc1a..a50018e2d4a0 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -12814,6 +12814,13 @@ static int check_map_prog_compatibility(struct bpf_verifier_env *env, { enum bpf_prog_type prog_type = resolve_prog_type(prog); + if (btf_record_has_field(map->record, BPF_LIST_HEAD)) { + if (is_tracing_prog_type(prog_type)) { + verbose(env, "tracing progs cannot use bpf_list_head yet\n"); + return -EINVAL; + } + } + if (btf_record_has_field(map->record, BPF_SPIN_LOCK)) { if (prog_type == BPF_PROG_TYPE_SOCKET_FILTER) { verbose(env, "socket filter progs cannot use bpf_spin_lock yet\n"); diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index fb4c911d2a03..6580448e9f77 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -6888,6 +6888,16 @@ struct bpf_dynptr { __u64 :64; } __attribute__((aligned(8))); +struct bpf_list_head { + __u64 :64; + __u64 :64; +} __attribute__((aligned(8))); + +struct bpf_list_node { + __u64 :64; + __u64 :64; +} __attribute__((aligned(8))); + struct bpf_sysctl { __u32 write; /* Sysctl is being read (= 0) or written (= 1). * Allows 1,2,4-byte read, but no write. From 2de2669b4e52b2ae2f118bfc310004f50b47f0f5 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Tue, 15 Nov 2022 00:45:26 +0530 Subject: [PATCH 010/101] bpf: Rename RET_PTR_TO_ALLOC_MEM Currently, the verifier has two return types, RET_PTR_TO_ALLOC_MEM, and RET_PTR_TO_ALLOC_MEM_OR_NULL, however the former is confusingly named to imply that it carries MEM_ALLOC, while only the latter does. This causes confusion during code review leading to conclusions like that the return value of RET_PTR_TO_DYNPTR_MEM_OR_NULL (which is RET_PTR_TO_ALLOC_MEM | PTR_MAYBE_NULL) may be consumable by bpf_ringbuf_{submit,commit}. Rename it to make it clear MEM_ALLOC needs to be tacked on top of RET_PTR_TO_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221114191547.1694267-6-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/linux/bpf.h | 6 +++--- kernel/bpf/verifier.c | 2 +- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 05f98e9e5c48..2fe3ec620d54 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -607,7 +607,7 @@ enum bpf_return_type { RET_PTR_TO_SOCKET, /* returns a pointer to a socket */ RET_PTR_TO_TCP_SOCK, /* returns a pointer to a tcp_sock */ RET_PTR_TO_SOCK_COMMON, /* returns a pointer to a sock_common */ - RET_PTR_TO_ALLOC_MEM, /* returns a pointer to dynamically allocated memory */ + RET_PTR_TO_MEM, /* returns a pointer to memory */ RET_PTR_TO_MEM_OR_BTF_ID, /* returns a pointer to a valid memory or a btf_id */ RET_PTR_TO_BTF_ID, /* returns a pointer to a btf_id */ __BPF_RET_TYPE_MAX, @@ -617,8 +617,8 @@ enum bpf_return_type { RET_PTR_TO_SOCKET_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_SOCKET, RET_PTR_TO_TCP_SOCK_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_TCP_SOCK, RET_PTR_TO_SOCK_COMMON_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_SOCK_COMMON, - RET_PTR_TO_ALLOC_MEM_OR_NULL = PTR_MAYBE_NULL | MEM_ALLOC | RET_PTR_TO_ALLOC_MEM, - RET_PTR_TO_DYNPTR_MEM_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_ALLOC_MEM, + RET_PTR_TO_ALLOC_MEM_OR_NULL = PTR_MAYBE_NULL | MEM_ALLOC | RET_PTR_TO_MEM, + RET_PTR_TO_DYNPTR_MEM_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_MEM, RET_PTR_TO_BTF_ID_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_BTF_ID, /* This must be the last entry. Its purpose is to ensure the enum is diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index a50018e2d4a0..c88da7e3ca74 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -7630,7 +7630,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn mark_reg_known_zero(env, regs, BPF_REG_0); regs[BPF_REG_0].type = PTR_TO_TCP_SOCK | ret_flag; break; - case RET_PTR_TO_ALLOC_MEM: + case RET_PTR_TO_MEM: mark_reg_known_zero(env, regs, BPF_REG_0); regs[BPF_REG_0].type = PTR_TO_MEM | ret_flag; regs[BPF_REG_0].mem_size = meta.mem_size; From 894f2a8b1673a355a1a7507a4dfa6a3c836d07c1 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Tue, 15 Nov 2022 00:45:27 +0530 Subject: [PATCH 011/101] bpf: Rename MEM_ALLOC to MEM_RINGBUF Currently, verifier uses MEM_ALLOC type tag to specially tag memory returned from bpf_ringbuf_reserve helper. However, this is currently only used for this purpose and there is an implicit assumption that it only refers to ringbuf memory (e.g. the check for ARG_PTR_TO_ALLOC_MEM in check_func_arg_reg_off). Hence, rename MEM_ALLOC to MEM_RINGBUF to indicate this special relationship and instead open the use of MEM_ALLOC for more generic allocations made for user types. Also, since ARG_PTR_TO_ALLOC_MEM_OR_NULL is unused, simply drop it. Finally, update selftests using 'alloc_' verifier string to 'ringbuf_'. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221114191547.1694267-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/linux/bpf.h | 11 ++++------- kernel/bpf/ringbuf.c | 6 +++--- kernel/bpf/verifier.c | 14 +++++++------- tools/testing/selftests/bpf/prog_tests/dynptr.c | 2 +- tools/testing/selftests/bpf/verifier/ringbuf.c | 2 +- tools/testing/selftests/bpf/verifier/spill_fill.c | 2 +- 6 files changed, 17 insertions(+), 20 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 2fe3ec620d54..afc1c51b59ff 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -488,10 +488,8 @@ enum bpf_type_flag { */ MEM_RDONLY = BIT(1 + BPF_BASE_TYPE_BITS), - /* MEM was "allocated" from a different helper, and cannot be mixed - * with regular non-MEM_ALLOC'ed MEM types. - */ - MEM_ALLOC = BIT(2 + BPF_BASE_TYPE_BITS), + /* MEM points to BPF ring buffer reservation. */ + MEM_RINGBUF = BIT(2 + BPF_BASE_TYPE_BITS), /* MEM is in user address space. */ MEM_USER = BIT(3 + BPF_BASE_TYPE_BITS), @@ -565,7 +563,7 @@ enum bpf_arg_type { ARG_PTR_TO_LONG, /* pointer to long */ ARG_PTR_TO_SOCKET, /* pointer to bpf_sock (fullsock) */ ARG_PTR_TO_BTF_ID, /* pointer to in-kernel struct */ - ARG_PTR_TO_ALLOC_MEM, /* pointer to dynamically allocated memory */ + ARG_PTR_TO_RINGBUF_MEM, /* pointer to dynamically reserved ringbuf memory */ ARG_CONST_ALLOC_SIZE_OR_ZERO, /* number of allocated bytes requested */ ARG_PTR_TO_BTF_ID_SOCK_COMMON, /* pointer to in-kernel sock_common or bpf-mirrored bpf_sock */ ARG_PTR_TO_PERCPU_BTF_ID, /* pointer to in-kernel percpu type */ @@ -582,7 +580,6 @@ enum bpf_arg_type { ARG_PTR_TO_MEM_OR_NULL = PTR_MAYBE_NULL | ARG_PTR_TO_MEM, ARG_PTR_TO_CTX_OR_NULL = PTR_MAYBE_NULL | ARG_PTR_TO_CTX, ARG_PTR_TO_SOCKET_OR_NULL = PTR_MAYBE_NULL | ARG_PTR_TO_SOCKET, - ARG_PTR_TO_ALLOC_MEM_OR_NULL = PTR_MAYBE_NULL | ARG_PTR_TO_ALLOC_MEM, ARG_PTR_TO_STACK_OR_NULL = PTR_MAYBE_NULL | ARG_PTR_TO_STACK, ARG_PTR_TO_BTF_ID_OR_NULL = PTR_MAYBE_NULL | ARG_PTR_TO_BTF_ID, /* pointer to memory does not need to be initialized, helper function must fill @@ -617,7 +614,7 @@ enum bpf_return_type { RET_PTR_TO_SOCKET_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_SOCKET, RET_PTR_TO_TCP_SOCK_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_TCP_SOCK, RET_PTR_TO_SOCK_COMMON_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_SOCK_COMMON, - RET_PTR_TO_ALLOC_MEM_OR_NULL = PTR_MAYBE_NULL | MEM_ALLOC | RET_PTR_TO_MEM, + RET_PTR_TO_RINGBUF_MEM_OR_NULL = PTR_MAYBE_NULL | MEM_RINGBUF | RET_PTR_TO_MEM, RET_PTR_TO_DYNPTR_MEM_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_MEM, RET_PTR_TO_BTF_ID_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_BTF_ID, diff --git a/kernel/bpf/ringbuf.c b/kernel/bpf/ringbuf.c index 9e832acf4692..80f4b4d88aaf 100644 --- a/kernel/bpf/ringbuf.c +++ b/kernel/bpf/ringbuf.c @@ -447,7 +447,7 @@ BPF_CALL_3(bpf_ringbuf_reserve, struct bpf_map *, map, u64, size, u64, flags) const struct bpf_func_proto bpf_ringbuf_reserve_proto = { .func = bpf_ringbuf_reserve, - .ret_type = RET_PTR_TO_ALLOC_MEM_OR_NULL, + .ret_type = RET_PTR_TO_RINGBUF_MEM_OR_NULL, .arg1_type = ARG_CONST_MAP_PTR, .arg2_type = ARG_CONST_ALLOC_SIZE_OR_ZERO, .arg3_type = ARG_ANYTHING, @@ -490,7 +490,7 @@ BPF_CALL_2(bpf_ringbuf_submit, void *, sample, u64, flags) const struct bpf_func_proto bpf_ringbuf_submit_proto = { .func = bpf_ringbuf_submit, .ret_type = RET_VOID, - .arg1_type = ARG_PTR_TO_ALLOC_MEM | OBJ_RELEASE, + .arg1_type = ARG_PTR_TO_RINGBUF_MEM | OBJ_RELEASE, .arg2_type = ARG_ANYTHING, }; @@ -503,7 +503,7 @@ BPF_CALL_2(bpf_ringbuf_discard, void *, sample, u64, flags) const struct bpf_func_proto bpf_ringbuf_discard_proto = { .func = bpf_ringbuf_discard, .ret_type = RET_VOID, - .arg1_type = ARG_PTR_TO_ALLOC_MEM | OBJ_RELEASE, + .arg1_type = ARG_PTR_TO_RINGBUF_MEM | OBJ_RELEASE, .arg2_type = ARG_ANYTHING, }; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index c88da7e3ca74..c588e5483540 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -577,8 +577,8 @@ static const char *reg_type_str(struct bpf_verifier_env *env, if (type & MEM_RDONLY) strncpy(prefix, "rdonly_", 32); - if (type & MEM_ALLOC) - strncpy(prefix, "alloc_", 32); + if (type & MEM_RINGBUF) + strncpy(prefix, "ringbuf_", 32); if (type & MEM_USER) strncpy(prefix, "user_", 32); if (type & MEM_PERCPU) @@ -5785,7 +5785,7 @@ static const struct bpf_reg_types mem_types = { PTR_TO_MAP_KEY, PTR_TO_MAP_VALUE, PTR_TO_MEM, - PTR_TO_MEM | MEM_ALLOC, + PTR_TO_MEM | MEM_RINGBUF, PTR_TO_BUF, }, }; @@ -5803,7 +5803,7 @@ static const struct bpf_reg_types int_ptr_types = { static const struct bpf_reg_types fullsock_types = { .types = { PTR_TO_SOCKET } }; static const struct bpf_reg_types scalar_types = { .types = { SCALAR_VALUE } }; static const struct bpf_reg_types context_types = { .types = { PTR_TO_CTX } }; -static const struct bpf_reg_types alloc_mem_types = { .types = { PTR_TO_MEM | MEM_ALLOC } }; +static const struct bpf_reg_types ringbuf_mem_types = { .types = { PTR_TO_MEM | MEM_RINGBUF } }; static const struct bpf_reg_types const_map_ptr_types = { .types = { CONST_PTR_TO_MAP } }; static const struct bpf_reg_types btf_ptr_types = { .types = { PTR_TO_BTF_ID } }; static const struct bpf_reg_types spin_lock_types = { .types = { PTR_TO_MAP_VALUE } }; @@ -5836,7 +5836,7 @@ static const struct bpf_reg_types *compatible_reg_types[__BPF_ARG_TYPE_MAX] = { [ARG_PTR_TO_BTF_ID] = &btf_ptr_types, [ARG_PTR_TO_SPIN_LOCK] = &spin_lock_types, [ARG_PTR_TO_MEM] = &mem_types, - [ARG_PTR_TO_ALLOC_MEM] = &alloc_mem_types, + [ARG_PTR_TO_RINGBUF_MEM] = &ringbuf_mem_types, [ARG_PTR_TO_INT] = &int_ptr_types, [ARG_PTR_TO_LONG] = &int_ptr_types, [ARG_PTR_TO_PERCPU_BTF_ID] = &percpu_btf_ptr_types, @@ -5957,14 +5957,14 @@ int check_func_arg_reg_off(struct bpf_verifier_env *env, case PTR_TO_MAP_VALUE: case PTR_TO_MEM: case PTR_TO_MEM | MEM_RDONLY: - case PTR_TO_MEM | MEM_ALLOC: + case PTR_TO_MEM | MEM_RINGBUF: case PTR_TO_BUF: case PTR_TO_BUF | MEM_RDONLY: case SCALAR_VALUE: /* Some of the argument types nevertheless require a * zero register offset. */ - if (base_type(arg_type) != ARG_PTR_TO_ALLOC_MEM) + if (base_type(arg_type) != ARG_PTR_TO_RINGBUF_MEM) return 0; break; /* All the rest must be rejected, except PTR_TO_BTF_ID which allows diff --git a/tools/testing/selftests/bpf/prog_tests/dynptr.c b/tools/testing/selftests/bpf/prog_tests/dynptr.c index 8fc4e6c02bfd..b0c06f821cb8 100644 --- a/tools/testing/selftests/bpf/prog_tests/dynptr.c +++ b/tools/testing/selftests/bpf/prog_tests/dynptr.c @@ -17,7 +17,7 @@ static struct { {"ringbuf_missing_release2", "Unreleased reference id=2"}, {"ringbuf_missing_release_callback", "Unreleased reference id"}, {"use_after_invalid", "Expected an initialized dynptr as arg #3"}, - {"ringbuf_invalid_api", "type=mem expected=alloc_mem"}, + {"ringbuf_invalid_api", "type=mem expected=ringbuf_mem"}, {"add_dynptr_to_map1", "invalid indirect read from stack"}, {"add_dynptr_to_map2", "invalid indirect read from stack"}, {"data_slice_out_of_bounds_ringbuf", "value is outside of the allowed memory range"}, diff --git a/tools/testing/selftests/bpf/verifier/ringbuf.c b/tools/testing/selftests/bpf/verifier/ringbuf.c index b64d33e4833c..84838feba47f 100644 --- a/tools/testing/selftests/bpf/verifier/ringbuf.c +++ b/tools/testing/selftests/bpf/verifier/ringbuf.c @@ -28,7 +28,7 @@ }, .fixup_map_ringbuf = { 1 }, .result = REJECT, - .errstr = "dereference of modified alloc_mem ptr R1", + .errstr = "dereference of modified ringbuf_mem ptr R1", }, { "ringbuf: invalid reservation offset 2", diff --git a/tools/testing/selftests/bpf/verifier/spill_fill.c b/tools/testing/selftests/bpf/verifier/spill_fill.c index e23f07175e1b..9bb302dade23 100644 --- a/tools/testing/selftests/bpf/verifier/spill_fill.c +++ b/tools/testing/selftests/bpf/verifier/spill_fill.c @@ -84,7 +84,7 @@ }, .fixup_map_ringbuf = { 1 }, .result = REJECT, - .errstr = "R0 pointer arithmetic on alloc_mem_or_null prohibited", + .errstr = "R0 pointer arithmetic on ringbuf_mem_or_null prohibited", }, { "check corrupted spill/fill", From 6728aea7216c0c06c98e2e58d753a5e8b2ae1c6f Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Tue, 15 Nov 2022 00:45:28 +0530 Subject: [PATCH 012/101] bpf: Refactor btf_struct_access Instead of having to pass multiple arguments that describe the register, pass the bpf_reg_state into the btf_struct_access callback. Currently, all call sites simply reuse the btf and btf_id of the reg they want to check the access of. The only exception to this pattern is the callsite in check_ptr_to_map_access, hence for that case create a dummy reg to simulate PTR_TO_BTF_ID access. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221114191547.1694267-8-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/linux/bpf.h | 17 ++++++++-------- include/linux/filter.h | 8 ++++---- kernel/bpf/btf.c | 11 +++++++---- kernel/bpf/verifier.c | 12 ++++++----- net/bpf/bpf_dummy_struct_ops.c | 14 ++++++------- net/core/filter.c | 34 +++++++++++++------------------- net/ipv4/bpf_tcp_ca.c | 13 ++++++------ net/netfilter/nf_conntrack_bpf.c | 17 +++++++--------- 8 files changed, 60 insertions(+), 66 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index afc1c51b59ff..49f9d2bec401 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -771,6 +771,7 @@ struct bpf_prog_ops { union bpf_attr __user *uattr); }; +struct bpf_reg_state; struct bpf_verifier_ops { /* return eBPF function prototype for verification */ const struct bpf_func_proto * @@ -792,9 +793,8 @@ struct bpf_verifier_ops { struct bpf_insn *dst, struct bpf_prog *prog, u32 *target_size); int (*btf_struct_access)(struct bpf_verifier_log *log, - const struct btf *btf, - const struct btf_type *t, int off, int size, - enum bpf_access_type atype, + const struct bpf_reg_state *reg, + int off, int size, enum bpf_access_type atype, u32 *next_btf_id, enum bpf_type_flag *flag); }; @@ -2080,9 +2080,9 @@ static inline bool bpf_tracing_btf_ctx_access(int off, int size, return btf_ctx_access(off, size, type, prog, info); } -int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf, - const struct btf_type *t, int off, int size, - enum bpf_access_type atype, +int btf_struct_access(struct bpf_verifier_log *log, + const struct bpf_reg_state *reg, + int off, int size, enum bpf_access_type atype, u32 *next_btf_id, enum bpf_type_flag *flag); bool btf_struct_ids_match(struct bpf_verifier_log *log, const struct btf *btf, u32 id, int off, @@ -2333,9 +2333,8 @@ static inline struct bpf_prog *bpf_prog_by_id(u32 id) } static inline int btf_struct_access(struct bpf_verifier_log *log, - const struct btf *btf, - const struct btf_type *t, int off, int size, - enum bpf_access_type atype, + const struct bpf_reg_state *reg, + int off, int size, enum bpf_access_type atype, u32 *next_btf_id, enum bpf_type_flag *flag) { return -EACCES; diff --git a/include/linux/filter.h b/include/linux/filter.h index efc42a6e3aed..787d35dbf5b0 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -568,10 +568,10 @@ struct sk_filter { DECLARE_STATIC_KEY_FALSE(bpf_stats_enabled_key); extern struct mutex nf_conn_btf_access_lock; -extern int (*nfct_btf_struct_access)(struct bpf_verifier_log *log, const struct btf *btf, - const struct btf_type *t, int off, int size, - enum bpf_access_type atype, u32 *next_btf_id, - enum bpf_type_flag *flag); +extern int (*nfct_btf_struct_access)(struct bpf_verifier_log *log, + const struct bpf_reg_state *reg, + int off, int size, enum bpf_access_type atype, + u32 *next_btf_id, enum bpf_type_flag *flag); typedef unsigned int (*bpf_dispatcher_fn)(const void *ctx, const struct bpf_insn *insnsi, diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index c0d73d71c539..875355ff3718 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -6017,15 +6017,18 @@ error: return -EINVAL; } -int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf, - const struct btf_type *t, int off, int size, - enum bpf_access_type atype __maybe_unused, +int btf_struct_access(struct bpf_verifier_log *log, + const struct bpf_reg_state *reg, + int off, int size, enum bpf_access_type atype __maybe_unused, u32 *next_btf_id, enum bpf_type_flag *flag) { + const struct btf *btf = reg->btf; enum bpf_type_flag tmp_flag = 0; + const struct btf_type *t; + u32 id = reg->btf_id; int err; - u32 id; + t = btf_type_by_id(btf, id); do { err = btf_struct_walk(log, btf, t, off, size, &id, &tmp_flag); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index c588e5483540..5e74f460dfd0 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4688,16 +4688,14 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env, } if (env->ops->btf_struct_access) { - ret = env->ops->btf_struct_access(&env->log, reg->btf, t, - off, size, atype, &btf_id, &flag); + ret = env->ops->btf_struct_access(&env->log, reg, off, size, atype, &btf_id, &flag); } else { if (atype != BPF_READ) { verbose(env, "only read is supported\n"); return -EACCES; } - ret = btf_struct_access(&env->log, reg->btf, t, off, size, - atype, &btf_id, &flag); + ret = btf_struct_access(&env->log, reg, off, size, atype, &btf_id, &flag); } if (ret < 0) @@ -4723,6 +4721,7 @@ static int check_ptr_to_map_access(struct bpf_verifier_env *env, { struct bpf_reg_state *reg = regs + regno; struct bpf_map *map = reg->map_ptr; + struct bpf_reg_state map_reg; enum bpf_type_flag flag = 0; const struct btf_type *t; const char *tname; @@ -4761,7 +4760,10 @@ static int check_ptr_to_map_access(struct bpf_verifier_env *env, return -EACCES; } - ret = btf_struct_access(&env->log, btf_vmlinux, t, off, size, atype, &btf_id, &flag); + /* Simulate access to a PTR_TO_BTF_ID */ + memset(&map_reg, 0, sizeof(map_reg)); + mark_btf_ld_reg(env, &map_reg, 0, PTR_TO_BTF_ID, btf_vmlinux, *map->ops->map_btf_id, 0); + ret = btf_struct_access(&env->log, &map_reg, off, size, atype, &btf_id, &flag); if (ret < 0) return ret; diff --git a/net/bpf/bpf_dummy_struct_ops.c b/net/bpf/bpf_dummy_struct_ops.c index e78dadfc5829..2d434c1f4617 100644 --- a/net/bpf/bpf_dummy_struct_ops.c +++ b/net/bpf/bpf_dummy_struct_ops.c @@ -156,29 +156,29 @@ static bool bpf_dummy_ops_is_valid_access(int off, int size, } static int bpf_dummy_ops_btf_struct_access(struct bpf_verifier_log *log, - const struct btf *btf, - const struct btf_type *t, int off, - int size, enum bpf_access_type atype, + const struct bpf_reg_state *reg, + int off, int size, enum bpf_access_type atype, u32 *next_btf_id, enum bpf_type_flag *flag) { const struct btf_type *state; + const struct btf_type *t; s32 type_id; int err; - type_id = btf_find_by_name_kind(btf, "bpf_dummy_ops_state", + type_id = btf_find_by_name_kind(reg->btf, "bpf_dummy_ops_state", BTF_KIND_STRUCT); if (type_id < 0) return -EINVAL; - state = btf_type_by_id(btf, type_id); + t = btf_type_by_id(reg->btf, reg->btf_id); + state = btf_type_by_id(reg->btf, type_id); if (t != state) { bpf_log(log, "only access to bpf_dummy_ops_state is supported\n"); return -EACCES; } - err = btf_struct_access(log, btf, t, off, size, atype, next_btf_id, - flag); + err = btf_struct_access(log, reg, off, size, atype, next_btf_id, flag); if (err < 0) return err; diff --git a/net/core/filter.c b/net/core/filter.c index 6dd2baf5eeb2..37fad5a9b752 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -8651,28 +8651,25 @@ static bool tc_cls_act_is_valid_access(int off, int size, DEFINE_MUTEX(nf_conn_btf_access_lock); EXPORT_SYMBOL_GPL(nf_conn_btf_access_lock); -int (*nfct_btf_struct_access)(struct bpf_verifier_log *log, const struct btf *btf, - const struct btf_type *t, int off, int size, - enum bpf_access_type atype, u32 *next_btf_id, - enum bpf_type_flag *flag); +int (*nfct_btf_struct_access)(struct bpf_verifier_log *log, + const struct bpf_reg_state *reg, + int off, int size, enum bpf_access_type atype, + u32 *next_btf_id, enum bpf_type_flag *flag); EXPORT_SYMBOL_GPL(nfct_btf_struct_access); static int tc_cls_act_btf_struct_access(struct bpf_verifier_log *log, - const struct btf *btf, - const struct btf_type *t, int off, - int size, enum bpf_access_type atype, - u32 *next_btf_id, - enum bpf_type_flag *flag) + const struct bpf_reg_state *reg, + int off, int size, enum bpf_access_type atype, + u32 *next_btf_id, enum bpf_type_flag *flag) { int ret = -EACCES; if (atype == BPF_READ) - return btf_struct_access(log, btf, t, off, size, atype, next_btf_id, - flag); + return btf_struct_access(log, reg, off, size, atype, next_btf_id, flag); mutex_lock(&nf_conn_btf_access_lock); if (nfct_btf_struct_access) - ret = nfct_btf_struct_access(log, btf, t, off, size, atype, next_btf_id, flag); + ret = nfct_btf_struct_access(log, reg, off, size, atype, next_btf_id, flag); mutex_unlock(&nf_conn_btf_access_lock); return ret; @@ -8738,21 +8735,18 @@ void bpf_warn_invalid_xdp_action(struct net_device *dev, struct bpf_prog *prog, EXPORT_SYMBOL_GPL(bpf_warn_invalid_xdp_action); static int xdp_btf_struct_access(struct bpf_verifier_log *log, - const struct btf *btf, - const struct btf_type *t, int off, - int size, enum bpf_access_type atype, - u32 *next_btf_id, - enum bpf_type_flag *flag) + const struct bpf_reg_state *reg, + int off, int size, enum bpf_access_type atype, + u32 *next_btf_id, enum bpf_type_flag *flag) { int ret = -EACCES; if (atype == BPF_READ) - return btf_struct_access(log, btf, t, off, size, atype, next_btf_id, - flag); + return btf_struct_access(log, reg, off, size, atype, next_btf_id, flag); mutex_lock(&nf_conn_btf_access_lock); if (nfct_btf_struct_access) - ret = nfct_btf_struct_access(log, btf, t, off, size, atype, next_btf_id, flag); + ret = nfct_btf_struct_access(log, reg, off, size, atype, next_btf_id, flag); mutex_unlock(&nf_conn_btf_access_lock); return ret; diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c index 6da16ae6a962..d15c91de995f 100644 --- a/net/ipv4/bpf_tcp_ca.c +++ b/net/ipv4/bpf_tcp_ca.c @@ -69,18 +69,17 @@ static bool bpf_tcp_ca_is_valid_access(int off, int size, } static int bpf_tcp_ca_btf_struct_access(struct bpf_verifier_log *log, - const struct btf *btf, - const struct btf_type *t, int off, - int size, enum bpf_access_type atype, - u32 *next_btf_id, - enum bpf_type_flag *flag) + const struct bpf_reg_state *reg, + int off, int size, enum bpf_access_type atype, + u32 *next_btf_id, enum bpf_type_flag *flag) { + const struct btf_type *t; size_t end; if (atype == BPF_READ) - return btf_struct_access(log, btf, t, off, size, atype, next_btf_id, - flag); + return btf_struct_access(log, reg, off, size, atype, next_btf_id, flag); + t = btf_type_by_id(reg->btf, reg->btf_id); if (t != tcp_sock_type) { bpf_log(log, "only read is supported\n"); return -EACCES; diff --git a/net/netfilter/nf_conntrack_bpf.c b/net/netfilter/nf_conntrack_bpf.c index 8639e7efd0e2..24002bc61e07 100644 --- a/net/netfilter/nf_conntrack_bpf.c +++ b/net/netfilter/nf_conntrack_bpf.c @@ -191,19 +191,16 @@ BTF_ID(struct, nf_conn___init) /* Check writes into `struct nf_conn` */ static int _nf_conntrack_btf_struct_access(struct bpf_verifier_log *log, - const struct btf *btf, - const struct btf_type *t, int off, - int size, enum bpf_access_type atype, - u32 *next_btf_id, - enum bpf_type_flag *flag) + const struct bpf_reg_state *reg, + int off, int size, enum bpf_access_type atype, + u32 *next_btf_id, enum bpf_type_flag *flag) { - const struct btf_type *ncit; - const struct btf_type *nct; + const struct btf_type *ncit, *nct, *t; size_t end; - ncit = btf_type_by_id(btf, btf_nf_conn_ids[1]); - nct = btf_type_by_id(btf, btf_nf_conn_ids[0]); - + ncit = btf_type_by_id(reg->btf, btf_nf_conn_ids[1]); + nct = btf_type_by_id(reg->btf, btf_nf_conn_ids[0]); + t = btf_type_by_id(reg->btf, reg->btf_id); if (t != nct && t != ncit) { bpf_log(log, "only read is supported\n"); return -EACCES; From 26a9b433cf08adf2fdb50775128b283eb5201ab2 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Daniel=20M=C3=BCller?= Date: Mon, 14 Nov 2022 21:15:01 +0000 Subject: [PATCH 013/101] bpf/docs: Document how to run CI without patch submission MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This change documents the process for running the BPF CI before submitting a patch to the upstream mailing list, similar to what happens if a patch is send to bpf@vger.kernel.org: it builds kernel and selftests and runs the latter on different architecture (but it notably does not cover stylistic checks such as cover letter verification). Running BPF CI this way can help achieve better test coverage ahead of patch submission than merely running locally (say, using tools/testing/selftests/bpf/vmtest.sh), as additional architectures may be covered as well. Signed-off-by: Daniel Müller Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20221114211501.2068684-1-deso@posteo.net --- Documentation/bpf/bpf_devel_QA.rst | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/Documentation/bpf/bpf_devel_QA.rst b/Documentation/bpf/bpf_devel_QA.rst index 761474bd7fe6..08572c75bdef 100644 --- a/Documentation/bpf/bpf_devel_QA.rst +++ b/Documentation/bpf/bpf_devel_QA.rst @@ -44,6 +44,30 @@ is a guarantee that the reported issue will be overlooked.** Submitting patches ================== +Q: How do I run BPF CI on my changes before sending them out for review? +------------------------------------------------------------------------ +A: BPF CI is GitHub based and hosted at https://github.com/kernel-patches/bpf. +While GitHub also provides a CLI that can be used to accomplish the same +results, here we focus on the UI based workflow. + +The following steps lay out how to start a CI run for your patches: +- Create a fork of the aforementioned repository in your own account (one time + action) +- Clone the fork locally, check out a new branch tracking either the bpf-next + or bpf branch, and apply your to-be-tested patches on top of it +- Push the local branch to your fork and create a pull request against + kernel-patches/bpf's bpf-next_base or bpf_base branch, respectively + +Shortly after the pull request has been created, the CI workflow will run. Note +that capacity is shared with patches submitted upstream being checked and so +depending on utilization the run can take a while to finish. + +Note furthermore that both base branches (bpf-next_base and bpf_base) will be +updated as patches are pushed to the respective upstream branches they track. As +such, your patch set will automatically (be attempted to) be rebased as well. +This behavior can result in a CI run being aborted and restarted with the new +base line. + Q: To which mailing list do I need to submit my BPF patches? ------------------------------------------------------------ A: Please submit your BPF patches to the bpf kernel mailing list: From 14d898f3c1b3bf9c4375ee3255ec9e9b89a35578 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= Date: Tue, 8 Nov 2022 15:05:59 +0100 Subject: [PATCH 014/101] dev: Move received_rps counter next to RPS members in softnet data MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Move the received_rps counter value next to the other RPS-related members in softnet_data. This closes two four-byte holes in the structure, making room for another pointer in the first two cache lines without bumping the xmit struct to its own line. Acked-by: Song Liu Reviewed-by: Stanislav Fomichev Signed-off-by: Toke Høiland-Jørgensen Link: https://lore.kernel.org/r/20221108140601.149971-2-toke@redhat.com Signed-off-by: Alexei Starovoitov --- include/linux/netdevice.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 02a2318da7c7..ddc59ef98500 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3128,7 +3128,6 @@ struct softnet_data { /* stats */ unsigned int processed; unsigned int time_squeeze; - unsigned int received_rps; #ifdef CONFIG_RPS struct softnet_data *rps_ipi_list; #endif @@ -3161,6 +3160,7 @@ struct softnet_data { unsigned int cpu; unsigned int input_queue_tail; #endif + unsigned int received_rps; unsigned int dropped; struct sk_buff_head input_pkt_queue; struct napi_struct backlog; From 32637e33003f36e75e9147788cc0e2f21706ef99 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= Date: Tue, 8 Nov 2022 15:06:00 +0100 Subject: [PATCH 015/101] bpf: Expand map key argument of bpf_redirect_map to u64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit For queueing packets in XDP we want to add a new redirect map type with support for 64-bit indexes. To prepare fore this, expand the width of the 'key' argument to the bpf_redirect_map() helper. Since BPF registers are always 64-bit, this should be safe to do after the fact. Acked-by: Song Liu Reviewed-by: Stanislav Fomichev Signed-off-by: Toke Høiland-Jørgensen Link: https://lore.kernel.org/r/20221108140601.149971-3-toke@redhat.com Signed-off-by: Alexei Starovoitov --- include/linux/bpf.h | 2 +- include/linux/filter.h | 12 ++++++------ include/uapi/linux/bpf.h | 2 +- kernel/bpf/cpumap.c | 4 ++-- kernel/bpf/devmap.c | 4 ++-- kernel/bpf/verifier.c | 2 +- net/core/filter.c | 4 ++-- net/xdp/xskmap.c | 4 ++-- 8 files changed, 17 insertions(+), 17 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 49f9d2bec401..54462dd28824 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -135,7 +135,7 @@ struct bpf_map_ops { struct bpf_local_storage __rcu ** (*map_owner_storage_ptr)(void *owner); /* Misc helpers.*/ - int (*map_redirect)(struct bpf_map *map, u32 ifindex, u64 flags); + int (*map_redirect)(struct bpf_map *map, u64 key, u64 flags); /* map_meta_equal must be implemented for maps that can be * used as an inner map. It is a runtime check to ensure diff --git a/include/linux/filter.h b/include/linux/filter.h index 787d35dbf5b0..bf701976056e 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -643,13 +643,13 @@ struct bpf_nh_params { }; struct bpf_redirect_info { - u32 flags; - u32 tgt_index; + u64 tgt_index; void *tgt_value; struct bpf_map *map; + u32 flags; + u32 kern_flags; u32 map_id; enum bpf_map_type map_type; - u32 kern_flags; struct bpf_nh_params nh; }; @@ -1504,7 +1504,7 @@ static inline bool bpf_sk_lookup_run_v6(struct net *net, int protocol, } #endif /* IS_ENABLED(CONFIG_IPV6) */ -static __always_inline int __bpf_xdp_redirect_map(struct bpf_map *map, u32 ifindex, +static __always_inline int __bpf_xdp_redirect_map(struct bpf_map *map, u64 index, u64 flags, const u64 flag_mask, void *lookup_elem(struct bpf_map *map, u32 key)) { @@ -1515,7 +1515,7 @@ static __always_inline int __bpf_xdp_redirect_map(struct bpf_map *map, u32 ifind if (unlikely(flags & ~(action_mask | flag_mask))) return XDP_ABORTED; - ri->tgt_value = lookup_elem(map, ifindex); + ri->tgt_value = lookup_elem(map, index); if (unlikely(!ri->tgt_value) && !(flags & BPF_F_BROADCAST)) { /* If the lookup fails we want to clear out the state in the * redirect_info struct completely, so that if an eBPF program @@ -1527,7 +1527,7 @@ static __always_inline int __bpf_xdp_redirect_map(struct bpf_map *map, u32 ifind return flags & action_mask; } - ri->tgt_index = ifindex; + ri->tgt_index = index; ri->map_id = map->id; ri->map_type = map->map_type; diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 6580448e9f77..ab86145df760 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -2647,7 +2647,7 @@ union bpf_attr { * Return * 0 on success, or a negative error in case of failure. * - * long bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags) + * long bpf_redirect_map(struct bpf_map *map, u64 key, u64 flags) * Description * Redirect the packet to the endpoint referenced by *map* at * index *key*. Depending on its type, this *map* can contain diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c index 6b6a78c04b90..e0b2d016f0bf 100644 --- a/kernel/bpf/cpumap.c +++ b/kernel/bpf/cpumap.c @@ -667,9 +667,9 @@ static int cpu_map_get_next_key(struct bpf_map *map, void *key, void *next_key) return 0; } -static int cpu_map_redirect(struct bpf_map *map, u32 ifindex, u64 flags) +static int cpu_map_redirect(struct bpf_map *map, u64 index, u64 flags) { - return __bpf_xdp_redirect_map(map, ifindex, flags, 0, + return __bpf_xdp_redirect_map(map, index, flags, 0, __cpu_map_lookup_elem); } diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index f9a87dcc5535..d01e4c55b376 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -992,14 +992,14 @@ static int dev_map_hash_update_elem(struct bpf_map *map, void *key, void *value, map, key, value, map_flags); } -static int dev_map_redirect(struct bpf_map *map, u32 ifindex, u64 flags) +static int dev_map_redirect(struct bpf_map *map, u64 ifindex, u64 flags) { return __bpf_xdp_redirect_map(map, ifindex, flags, BPF_F_BROADCAST | BPF_F_EXCLUDE_INGRESS, __dev_map_lookup_elem); } -static int dev_hash_map_redirect(struct bpf_map *map, u32 ifindex, u64 flags) +static int dev_hash_map_redirect(struct bpf_map *map, u64 ifindex, u64 flags) { return __bpf_xdp_redirect_map(map, ifindex, flags, BPF_F_BROADCAST | BPF_F_EXCLUDE_INGRESS, diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 5e74f460dfd0..be24774961ab 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -14384,7 +14384,7 @@ static int do_misc_fixups(struct bpf_verifier_env *env) BUILD_BUG_ON(!__same_type(ops->map_peek_elem, (int (*)(struct bpf_map *map, void *value))NULL)); BUILD_BUG_ON(!__same_type(ops->map_redirect, - (int (*)(struct bpf_map *map, u32 ifindex, u64 flags))NULL)); + (int (*)(struct bpf_map *map, u64 index, u64 flags))NULL)); BUILD_BUG_ON(!__same_type(ops->map_for_each_callback, (int (*)(struct bpf_map *map, bpf_callback_t callback_fn, diff --git a/net/core/filter.c b/net/core/filter.c index 37fad5a9b752..754dd01354d8 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -4414,10 +4414,10 @@ static const struct bpf_func_proto bpf_xdp_redirect_proto = { .arg2_type = ARG_ANYTHING, }; -BPF_CALL_3(bpf_xdp_redirect_map, struct bpf_map *, map, u32, ifindex, +BPF_CALL_3(bpf_xdp_redirect_map, struct bpf_map *, map, u64, key, u64, flags) { - return map->ops->map_redirect(map, ifindex, flags); + return map->ops->map_redirect(map, key, flags); } static const struct bpf_func_proto bpf_xdp_redirect_map_proto = { diff --git a/net/xdp/xskmap.c b/net/xdp/xskmap.c index acc8e52a4f5f..771d0fa90ef5 100644 --- a/net/xdp/xskmap.c +++ b/net/xdp/xskmap.c @@ -231,9 +231,9 @@ static int xsk_map_delete_elem(struct bpf_map *map, void *key) return 0; } -static int xsk_map_redirect(struct bpf_map *map, u32 ifindex, u64 flags) +static int xsk_map_redirect(struct bpf_map *map, u64 index, u64 flags) { - return __bpf_xdp_redirect_map(map, ifindex, flags, 0, + return __bpf_xdp_redirect_map(map, index, flags, 0, __xsk_map_lookup_elem); } From befae75856ab406a3f3fab2aa2118cf3b2dfe3e6 Mon Sep 17 00:00:00 2001 From: Eduard Zingerman Date: Wed, 16 Nov 2022 00:48:58 +0200 Subject: [PATCH 016/101] bpf: propagate nullness information for reg to reg comparisons Propagate nullness information for branches of register to register equality compare instructions. The following rules are used: - suppose register A maybe null - suppose register B is not null - for JNE A, B, ... - A is not null in the false branch - for JEQ A, B, ... - A is not null in the true branch E.g. for program like below: r6 = skb->sk; r7 = sk_fullsock(r6); r0 = sk_fullsock(r6); if (r0 == 0) return 0; (a) if (r0 != r7) return 0; (b) *r7->type; (c) return 0; It is safe to dereference r7 at point (c), because of (a) and (b). Signed-off-by: Eduard Zingerman Acked-by: Yonghong Song Link: https://lore.kernel.org/r/20221115224859.2452988-2-eddyz87@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 35 +++++++++++++++++++++++++++++++++-- 1 file changed, 33 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index be24774961ab..0312d9ce292f 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -10267,6 +10267,7 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, struct bpf_verifier_state *other_branch; struct bpf_reg_state *regs = this_branch->frame[this_branch->curframe]->regs; struct bpf_reg_state *dst_reg, *other_branch_regs, *src_reg = NULL; + struct bpf_reg_state *eq_branch_regs; u8 opcode = BPF_OP(insn->code); bool is_jmp32; int pred = -1; @@ -10376,8 +10377,8 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, /* detect if we are comparing against a constant value so we can adjust * our min/max values for our dst register. * this is only legit if both are scalars (or pointers to the same - * object, I suppose, but we don't support that right now), because - * otherwise the different base pointers mean the offsets aren't + * object, I suppose, see the PTR_MAYBE_NULL related if block below), + * because otherwise the different base pointers mean the offsets aren't * comparable. */ if (BPF_SRC(insn->code) == BPF_X) { @@ -10426,6 +10427,36 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, find_equal_scalars(other_branch, &other_branch_regs[insn->dst_reg]); } + /* if one pointer register is compared to another pointer + * register check if PTR_MAYBE_NULL could be lifted. + * E.g. register A - maybe null + * register B - not null + * for JNE A, B, ... - A is not null in the false branch; + * for JEQ A, B, ... - A is not null in the true branch. + */ + if (!is_jmp32 && BPF_SRC(insn->code) == BPF_X && + __is_pointer_value(false, src_reg) && __is_pointer_value(false, dst_reg) && + type_may_be_null(src_reg->type) != type_may_be_null(dst_reg->type)) { + eq_branch_regs = NULL; + switch (opcode) { + case BPF_JEQ: + eq_branch_regs = other_branch_regs; + break; + case BPF_JNE: + eq_branch_regs = regs; + break; + default: + /* do nothing */ + break; + } + if (eq_branch_regs) { + if (type_may_be_null(src_reg->type)) + mark_ptr_not_null_reg(&eq_branch_regs[insn->src_reg]); + else + mark_ptr_not_null_reg(&eq_branch_regs[insn->dst_reg]); + } + } + /* detect if R == 0 where R is returned from bpf_map_lookup_elem(). * NOTE: these optimizations below are related with pointer comparison * which will never be JMP32. From 4741c371aa088a951bd65f995d2dfe7cd29b4b9a Mon Sep 17 00:00:00 2001 From: Eduard Zingerman Date: Wed, 16 Nov 2022 00:48:59 +0200 Subject: [PATCH 017/101] selftests/bpf: check nullness propagation for reg to reg comparisons Verify that nullness information is porpagated in the branches of register to register JEQ and JNE operations. Signed-off-by: Eduard Zingerman Acked-by: Yonghong Song Link: https://lore.kernel.org/r/20221115224859.2452988-3-eddyz87@gmail.com Signed-off-by: Alexei Starovoitov --- .../bpf/verifier/jeq_infer_not_null.c | 174 ++++++++++++++++++ 1 file changed, 174 insertions(+) create mode 100644 tools/testing/selftests/bpf/verifier/jeq_infer_not_null.c diff --git a/tools/testing/selftests/bpf/verifier/jeq_infer_not_null.c b/tools/testing/selftests/bpf/verifier/jeq_infer_not_null.c new file mode 100644 index 000000000000..67a1c07ead34 --- /dev/null +++ b/tools/testing/selftests/bpf/verifier/jeq_infer_not_null.c @@ -0,0 +1,174 @@ +{ + /* This is equivalent to the following program: + * + * r6 = skb->sk; + * r7 = sk_fullsock(r6); + * r0 = sk_fullsock(r6); + * if (r0 == 0) return 0; (a) + * if (r0 != r7) return 0; (b) + * *r7->type; (c) + * return 0; + * + * It is safe to dereference r7 at point (c), because of (a) and (b). + * The test verifies that relation r0 == r7 is propagated from (b) to (c). + */ + "jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL -> PTR_TO_SOCKET for JNE false branch", + .insns = { + /* r6 = skb->sk; */ + BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, offsetof(struct __sk_buff, sk)), + /* if (r6 == 0) return 0; */ + BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 8), + /* r7 = sk_fullsock(skb); */ + BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), + BPF_EMIT_CALL(BPF_FUNC_sk_fullsock), + BPF_MOV64_REG(BPF_REG_7, BPF_REG_0), + /* r0 = sk_fullsock(skb); */ + BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), + BPF_EMIT_CALL(BPF_FUNC_sk_fullsock), + /* if (r0 == null) return 0; */ + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2), + /* if (r0 == r7) r0 = *(r7->type); */ + BPF_JMP_REG(BPF_JNE, BPF_REG_0, BPF_REG_7, 1), /* Use ! JNE ! */ + BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_sock, type)), + /* return 0 */ + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_CGROUP_SKB, + .result = ACCEPT, + .result_unpriv = REJECT, + .errstr_unpriv = "R7 pointer comparison", +}, +{ + /* Same as above, but verify that another branch of JNE still + * prohibits access to PTR_MAYBE_NULL. + */ + "jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL unchanged for JNE true branch", + .insns = { + /* r6 = skb->sk */ + BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, offsetof(struct __sk_buff, sk)), + /* if (r6 == 0) return 0; */ + BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 9), + /* r7 = sk_fullsock(skb); */ + BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), + BPF_EMIT_CALL(BPF_FUNC_sk_fullsock), + BPF_MOV64_REG(BPF_REG_7, BPF_REG_0), + /* r0 = sk_fullsock(skb); */ + BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), + BPF_EMIT_CALL(BPF_FUNC_sk_fullsock), + /* if (r0 == null) return 0; */ + BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 3), + /* if (r0 == r7) return 0; */ + BPF_JMP_REG(BPF_JNE, BPF_REG_0, BPF_REG_7, 1), /* Use ! JNE ! */ + BPF_JMP_IMM(BPF_JA, 0, 0, 1), + /* r0 = *(r7->type); */ + BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_sock, type)), + /* return 0 */ + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_CGROUP_SKB, + .result = REJECT, + .errstr = "R7 invalid mem access 'sock_or_null'", + .result_unpriv = REJECT, + .errstr_unpriv = "R7 pointer comparison", +}, +{ + /* Same as a first test, but not null should be inferred for JEQ branch */ + "jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL -> PTR_TO_SOCKET for JEQ true branch", + .insns = { + /* r6 = skb->sk; */ + BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, offsetof(struct __sk_buff, sk)), + /* if (r6 == null) return 0; */ + BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 9), + /* r7 = sk_fullsock(skb); */ + BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), + BPF_EMIT_CALL(BPF_FUNC_sk_fullsock), + BPF_MOV64_REG(BPF_REG_7, BPF_REG_0), + /* r0 = sk_fullsock(skb); */ + BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), + BPF_EMIT_CALL(BPF_FUNC_sk_fullsock), + /* if (r0 == null) return 0; */ + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3), + /* if (r0 != r7) return 0; */ + BPF_JMP_REG(BPF_JEQ, BPF_REG_0, BPF_REG_7, 1), /* Use ! JEQ ! */ + BPF_JMP_IMM(BPF_JA, 0, 0, 1), + /* r0 = *(r7->type); */ + BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_sock, type)), + /* return 0; */ + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_CGROUP_SKB, + .result = ACCEPT, + .result_unpriv = REJECT, + .errstr_unpriv = "R7 pointer comparison", +}, +{ + /* Same as above, but verify that another branch of JNE still + * prohibits access to PTR_MAYBE_NULL. + */ + "jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL unchanged for JEQ false branch", + .insns = { + /* r6 = skb->sk; */ + BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, offsetof(struct __sk_buff, sk)), + /* if (r6 == null) return 0; */ + BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 8), + /* r7 = sk_fullsock(skb); */ + BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), + BPF_EMIT_CALL(BPF_FUNC_sk_fullsock), + BPF_MOV64_REG(BPF_REG_7, BPF_REG_0), + /* r0 = sk_fullsock(skb); */ + BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), + BPF_EMIT_CALL(BPF_FUNC_sk_fullsock), + /* if (r0 == null) return 0; */ + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2), + /* if (r0 != r7) r0 = *(r7->type); */ + BPF_JMP_REG(BPF_JEQ, BPF_REG_0, BPF_REG_7, 1), /* Use ! JEQ ! */ + BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_sock, type)), + /* return 0; */ + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_CGROUP_SKB, + .result = REJECT, + .errstr = "R7 invalid mem access 'sock_or_null'", + .result_unpriv = REJECT, + .errstr_unpriv = "R7 pointer comparison", +}, +{ + /* Maps are treated in a different branch of `mark_ptr_not_null_reg`, + * so separate test for maps case. + */ + "jne/jeq infer not null, PTR_TO_MAP_VALUE_OR_NULL -> PTR_TO_MAP_VALUE", + .insns = { + /* r9 = &some stack to use as key */ + BPF_ST_MEM(BPF_W, BPF_REG_10, -8, 0), + BPF_MOV64_REG(BPF_REG_9, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_9, -8), + /* r8 = process local map */ + BPF_LD_MAP_FD(BPF_REG_8, 0), + /* r6 = map_lookup_elem(r8, r9); */ + BPF_MOV64_REG(BPF_REG_1, BPF_REG_8), + BPF_MOV64_REG(BPF_REG_2, BPF_REG_9), + BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_MOV64_REG(BPF_REG_6, BPF_REG_0), + /* r7 = map_lookup_elem(r8, r9); */ + BPF_MOV64_REG(BPF_REG_1, BPF_REG_8), + BPF_MOV64_REG(BPF_REG_2, BPF_REG_9), + BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_MOV64_REG(BPF_REG_7, BPF_REG_0), + /* if (r6 == 0) return 0; */ + BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 2), + /* if (r6 != r7) return 0; */ + BPF_JMP_REG(BPF_JNE, BPF_REG_6, BPF_REG_7, 1), + /* read *r7; */ + BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_xdp_sock, queue_id)), + /* return 0; */ + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .fixup_map_xskmap = { 3 }, + .prog_type = BPF_PROG_TYPE_XDP, + .result = ACCEPT, +}, From e0eb60829a6eb249d7c6cccef0605c3004004bef Mon Sep 17 00:00:00 2001 From: Donald Hunter Date: Tue, 15 Nov 2022 09:59:10 +0000 Subject: [PATCH 018/101] docs/bpf: Fix sample code in MAP_TYPE_ARRAY docs Remove mistaken & from code example in MAP_TYPE_ARRAY docs Fixes: 1cfa97b30c5a ("bpf, docs: Document BPF_MAP_TYPE_ARRAY") Signed-off-by: Donald Hunter Link: https://lore.kernel.org/r/20221115095910.86407-1-donald.hunter@gmail.com Signed-off-by: Alexei Starovoitov --- Documentation/bpf/map_array.rst | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Documentation/bpf/map_array.rst b/Documentation/bpf/map_array.rst index b2cceb6c696b..97bb80333254 100644 --- a/Documentation/bpf/map_array.rst +++ b/Documentation/bpf/map_array.rst @@ -119,7 +119,7 @@ This example BPF program shows how to access an array element. index = ip.protocol; value = bpf_map_lookup_elem(&my_map, &index); if (value) - __sync_fetch_and_add(&value, skb->len); + __sync_fetch_and_add(value, skb->len); return 0; } From df9c41e9db2d0fc9feba0423c21e4319d8acd033 Mon Sep 17 00:00:00 2001 From: Tiezhu Yang Date: Tue, 15 Nov 2022 21:00:07 +0800 Subject: [PATCH 019/101] bpftool: Check argc first before "file" in do_batch() If the parameters for batch are more than 2, check argc first can return immediately, no need to use is_prefix() to check "file" with a little overhead and then check argc, it is better to check "file" only when the parameters for batch are 2. Signed-off-by: Tiezhu Yang Acked-by: Stanislav Fomichev Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/r/1668517207-11822-1-git-send-email-yangtiezhu@loongson.cn Signed-off-by: Alexei Starovoitov --- tools/bpf/bpftool/main.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c index 741e50ee0b6c..337ab7977ea4 100644 --- a/tools/bpf/bpftool/main.c +++ b/tools/bpf/bpftool/main.c @@ -337,12 +337,12 @@ static int do_batch(int argc, char **argv) if (argc < 2) { p_err("too few parameters for batch"); return -1; - } else if (!is_prefix(*argv, "file")) { - p_err("expected 'file', got: %s", *argv); - return -1; } else if (argc > 2) { p_err("too many parameters for batch"); return -1; + } else if (!is_prefix(*argv, "file")) { + p_err("expected 'file', got: %s", *argv); + return -1; } NEXT_ARG(); From 5b1d640800de7fe02d68bf592d9d101de24c87f2 Mon Sep 17 00:00:00 2001 From: Eduard Zingerman Date: Wed, 16 Nov 2022 03:54:56 +0200 Subject: [PATCH 020/101] selftests/bpf: allow unpriv bpf for selftests by default Enable unprivileged bpf for selftests kernel by default. This forces CI to run test_verifier tests in both privileged and unprivileged modes. The test_verifier.c:do_test uses sysctl kernel.unprivileged_bpf_disabled to decide whether to run or to skip test cases in unprivileged mode. The CONFIG_BPF_UNPRIV_DEFAULT_OFF controls the default value of the kernel.unprivileged_bpf_disabled. Signed-off-by: Eduard Zingerman Link: https://lore.kernel.org/r/20221116015456.2461135-1-eddyz87@gmail.com Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/config | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config index 7a99a6728169..f9034ea00bc9 100644 --- a/tools/testing/selftests/bpf/config +++ b/tools/testing/selftests/bpf/config @@ -8,6 +8,7 @@ CONFIG_BPF_LIRC_MODE2=y CONFIG_BPF_LSM=y CONFIG_BPF_STREAM_PARSER=y CONFIG_BPF_SYSCALL=y +CONFIG_BPF_UNPRIV_DEFAULT_OFF=n CONFIG_CGROUP_BPF=y CONFIG_CRYPTO_HMAC=y CONFIG_CRYPTO_SHA256=y From c453e64cbc9532c0c2edfa999c35d29dad16b8bb Mon Sep 17 00:00:00 2001 From: Wang Yufen Date: Tue, 15 Nov 2022 11:29:40 +0800 Subject: [PATCH 021/101] selftests/bpf: fix memory leak of lsm_cgroup kmemleak reports this issue: unreferenced object 0xffff88810b7835c0 (size 32): comm "test_progs", pid 270, jiffies 4294969007 (age 1621.315s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 03 00 00 00 03 00 00 00 0f 00 00 00 00 00 00 00 ................ backtrace: [<00000000376cdeab>] kmalloc_trace+0x27/0x110 [<000000003bcdb3b6>] selinux_sk_alloc_security+0x66/0x110 [<000000003959008f>] security_sk_alloc+0x47/0x80 [<00000000e7bc6668>] sk_prot_alloc+0xbd/0x1a0 [<0000000002d6343a>] sk_alloc+0x3b/0x940 [<000000009812a46d>] unix_create1+0x8f/0x3d0 [<000000005ed0976b>] unix_create+0xa1/0x150 [<0000000086a1d27f>] __sock_create+0x233/0x4a0 [<00000000cffe3a73>] __sys_socket_create.part.0+0xaa/0x110 [<0000000007c63f20>] __sys_socket+0x49/0xf0 [<00000000b08753c8>] __x64_sys_socket+0x42/0x50 [<00000000b56e26b3>] do_syscall_64+0x3b/0x90 [<000000009b4871b8>] entry_SYSCALL_64_after_hwframe+0x63/0xcd The issue occurs in the following scenarios: unix_create1() sk_alloc() sk_prot_alloc() security_sk_alloc() call_int_hook() hlist_for_each_entry() entry1->hook.sk_alloc_security <-- selinux_sk_alloc_security() succeeded, <-- sk->security alloced here. entry2->hook.sk_alloc_security <-- bpf_lsm_sk_alloc_security() failed goto out_free; ... <-- the sk->security not freed, memleak The core problem is that the LSM is not yet fully stacked (work is actively going on in this space) which means that some LSM hooks do not support multiple LSMs at the same time. To fix, skip the "EPERM" test when it runs in the environments that already have non-bpf lsms installed Fixes: dca85aac8895 ("selftests/bpf: lsm_cgroup functional test") Signed-off-by: Wang Yufen Cc: Stanislav Fomichev Acked-by: Stanislav Fomichev Link: https://lore.kernel.org/r/1668482980-16163-1-git-send-email-wangyufen@huawei.com Signed-off-by: Martin KaFai Lau --- .../selftests/bpf/prog_tests/lsm_cgroup.c | 17 +++++++++++++---- tools/testing/selftests/bpf/progs/lsm_cgroup.c | 8 ++++++++ 2 files changed, 21 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/lsm_cgroup.c b/tools/testing/selftests/bpf/prog_tests/lsm_cgroup.c index 1102e4f42d2d..f117bfef68a1 100644 --- a/tools/testing/selftests/bpf/prog_tests/lsm_cgroup.c +++ b/tools/testing/selftests/bpf/prog_tests/lsm_cgroup.c @@ -173,10 +173,12 @@ static void test_lsm_cgroup_functional(void) ASSERT_EQ(query_prog_cnt(cgroup_fd, NULL), 4, "total prog count"); ASSERT_EQ(query_prog_cnt(cgroup_fd2, NULL), 1, "total prog count"); - /* AF_UNIX is prohibited. */ - fd = socket(AF_UNIX, SOCK_STREAM, 0); - ASSERT_LT(fd, 0, "socket(AF_UNIX)"); + if (!(skel->kconfig->CONFIG_SECURITY_APPARMOR + || skel->kconfig->CONFIG_SECURITY_SELINUX + || skel->kconfig->CONFIG_SECURITY_SMACK)) + /* AF_UNIX is prohibited. */ + ASSERT_LT(fd, 0, "socket(AF_UNIX)"); close(fd); /* AF_INET6 gets default policy (sk_priority). */ @@ -233,11 +235,18 @@ static void test_lsm_cgroup_functional(void) /* AF_INET6+SOCK_STREAM * AF_PACKET+SOCK_RAW + * AF_UNIX+SOCK_RAW if already have non-bpf lsms installed * listen_fd * client_fd * accepted_fd */ - ASSERT_EQ(skel->bss->called_socket_post_create2, 5, "called_create2"); + if (skel->kconfig->CONFIG_SECURITY_APPARMOR + || skel->kconfig->CONFIG_SECURITY_SELINUX + || skel->kconfig->CONFIG_SECURITY_SMACK) + /* AF_UNIX+SOCK_RAW if already have non-bpf lsms installed */ + ASSERT_EQ(skel->bss->called_socket_post_create2, 6, "called_create2"); + else + ASSERT_EQ(skel->bss->called_socket_post_create2, 5, "called_create2"); /* start_server * bind(ETH_P_ALL) diff --git a/tools/testing/selftests/bpf/progs/lsm_cgroup.c b/tools/testing/selftests/bpf/progs/lsm_cgroup.c index 4f2d60b87b75..02c11d16b692 100644 --- a/tools/testing/selftests/bpf/progs/lsm_cgroup.c +++ b/tools/testing/selftests/bpf/progs/lsm_cgroup.c @@ -7,6 +7,10 @@ char _license[] SEC("license") = "GPL"; +extern bool CONFIG_SECURITY_SELINUX __kconfig __weak; +extern bool CONFIG_SECURITY_SMACK __kconfig __weak; +extern bool CONFIG_SECURITY_APPARMOR __kconfig __weak; + #ifndef AF_PACKET #define AF_PACKET 17 #endif @@ -140,6 +144,10 @@ SEC("lsm_cgroup/sk_alloc_security") int BPF_PROG(socket_alloc, struct sock *sk, int family, gfp_t priority) { called_socket_alloc++; + /* if already have non-bpf lsms installed, EPERM will cause memory leak of non-bpf lsms */ + if (CONFIG_SECURITY_SELINUX || CONFIG_SECURITY_SMACK || CONFIG_SECURITY_APPARMOR) + return 1; + if (family == AF_UNIX) return 0; /* EPERM */ From 383f1a8df8faba88a3bafaddc02f59421bad6829 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Daniel=20M=C3=BCller?= Date: Wed, 16 Nov 2022 17:43:58 +0000 Subject: [PATCH 022/101] bpf/docs: Include blank lines between bullet points in bpf_devel_QA.rst MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit 26a9b433cf08 ("bpf/docs: Document how to run CI without patch submission") caused a warning to be generated when compiling the documentation: > bpf_devel_QA.rst:55: WARNING: Unexpected indentation. > bpf_devel_QA.rst:56: WARNING: Block quote ends without a blank line This change fixes the problem by inserting the required blank lines. Fixes: 26a9b433cf08 ("bpf/docs: Document how to run CI without patch submission") Reported-by: Akira Yokosawa Signed-off-by: Daniel Müller Signed-off-by: Daniel Borkmann Reviewed-by: Akira Yokosawa Link: https://lore.kernel.org/bpf/20221116174358.2744613-1-deso@posteo.net --- Documentation/bpf/bpf_devel_QA.rst | 3 +++ 1 file changed, 3 insertions(+) diff --git a/Documentation/bpf/bpf_devel_QA.rst b/Documentation/bpf/bpf_devel_QA.rst index 08572c75bdef..03d4993eda6f 100644 --- a/Documentation/bpf/bpf_devel_QA.rst +++ b/Documentation/bpf/bpf_devel_QA.rst @@ -51,10 +51,13 @@ While GitHub also provides a CLI that can be used to accomplish the same results, here we focus on the UI based workflow. The following steps lay out how to start a CI run for your patches: + - Create a fork of the aforementioned repository in your own account (one time action) + - Clone the fork locally, check out a new branch tracking either the bpf-next or bpf branch, and apply your to-be-tested patches on top of it + - Push the local branch to your fork and create a pull request against kernel-patches/bpf's bpf-next_base or bpf_base branch, respectively From 3af43ba4c6019b29c048921eb8147eb010165329 Mon Sep 17 00:00:00 2001 From: Hou Tao Date: Wed, 16 Nov 2022 15:50:58 +0800 Subject: [PATCH 023/101] bpf: Pass map file to .map_update_batch directly Currently bpf_map_do_batch() first invokes fdget(batch.map_fd) to get the target map file, then it invokes generic_map_update_batch() to do batch update. generic_map_update_batch() will get the target map file by using fdget(batch.map_fd) again and pass it to bpf_map_update_value(). The problem is map file returned by the second fdget() may be NULL or a totally different file compared by map file in bpf_map_do_batch(). The reason is that the first fdget() only guarantees the liveness of struct file instead of file descriptor and the file description may be released by concurrent close() through pick_file(). It doesn't incur any problem as for now, because maps with batch update support don't use map file in .map_fd_get_ptr() ops. But it is better to fix the potential access of an invalid map file. Using __bpf_map_get() again in generic_map_update_batch() can not fix the problem, because batch.map_fd may be closed and reopened, and the returned map file may be different with map file got in bpf_map_do_batch(), so just passing the map file directly to .map_update_batch() in bpf_map_do_batch(). Signed-off-by: Hou Tao Signed-off-by: Daniel Borkmann Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20221116075059.1551277-1-houtao@huaweicloud.com --- include/linux/bpf.h | 5 +++-- kernel/bpf/syscall.c | 32 ++++++++++++++------------------ 2 files changed, 17 insertions(+), 20 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 54462dd28824..e60a5c052473 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -85,7 +85,8 @@ struct bpf_map_ops { int (*map_lookup_and_delete_batch)(struct bpf_map *map, const union bpf_attr *attr, union bpf_attr __user *uattr); - int (*map_update_batch)(struct bpf_map *map, const union bpf_attr *attr, + int (*map_update_batch)(struct bpf_map *map, struct file *map_file, + const union bpf_attr *attr, union bpf_attr __user *uattr); int (*map_delete_batch)(struct bpf_map *map, const union bpf_attr *attr, union bpf_attr __user *uattr); @@ -1789,7 +1790,7 @@ void bpf_map_init_from_attr(struct bpf_map *map, union bpf_attr *attr); int generic_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr, union bpf_attr __user *uattr); -int generic_map_update_batch(struct bpf_map *map, +int generic_map_update_batch(struct bpf_map *map, struct file *map_file, const union bpf_attr *attr, union bpf_attr __user *uattr); int generic_map_delete_batch(struct bpf_map *map, diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index fdbae52f463f..b078965999e6 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -175,8 +175,8 @@ static void maybe_wait_bpf_programs(struct bpf_map *map) synchronize_rcu(); } -static int bpf_map_update_value(struct bpf_map *map, struct fd f, void *key, - void *value, __u64 flags) +static int bpf_map_update_value(struct bpf_map *map, struct file *map_file, + void *key, void *value, __u64 flags) { int err; @@ -190,7 +190,7 @@ static int bpf_map_update_value(struct bpf_map *map, struct fd f, void *key, map->map_type == BPF_MAP_TYPE_SOCKMAP) { return sock_map_update_elem_sys(map, key, value, flags); } else if (IS_FD_PROG_ARRAY(map)) { - return bpf_fd_array_map_update_elem(map, f.file, key, value, + return bpf_fd_array_map_update_elem(map, map_file, key, value, flags); } @@ -205,12 +205,12 @@ static int bpf_map_update_value(struct bpf_map *map, struct fd f, void *key, flags); } else if (IS_FD_ARRAY(map)) { rcu_read_lock(); - err = bpf_fd_array_map_update_elem(map, f.file, key, value, + err = bpf_fd_array_map_update_elem(map, map_file, key, value, flags); rcu_read_unlock(); } else if (map->map_type == BPF_MAP_TYPE_HASH_OF_MAPS) { rcu_read_lock(); - err = bpf_fd_htab_map_update_elem(map, f.file, key, value, + err = bpf_fd_htab_map_update_elem(map, map_file, key, value, flags); rcu_read_unlock(); } else if (map->map_type == BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) { @@ -1410,7 +1410,7 @@ static int map_update_elem(union bpf_attr *attr, bpfptr_t uattr) goto free_key; } - err = bpf_map_update_value(map, f, key, value, attr->flags); + err = bpf_map_update_value(map, f.file, key, value, attr->flags); kvfree(value); free_key: @@ -1596,16 +1596,14 @@ int generic_map_delete_batch(struct bpf_map *map, return err; } -int generic_map_update_batch(struct bpf_map *map, +int generic_map_update_batch(struct bpf_map *map, struct file *map_file, const union bpf_attr *attr, union bpf_attr __user *uattr) { void __user *values = u64_to_user_ptr(attr->batch.values); void __user *keys = u64_to_user_ptr(attr->batch.keys); u32 value_size, cp, max_count; - int ufd = attr->batch.map_fd; void *key, *value; - struct fd f; int err = 0; if (attr->batch.elem_flags & ~BPF_F_LOCK) @@ -1632,7 +1630,6 @@ int generic_map_update_batch(struct bpf_map *map, return -ENOMEM; } - f = fdget(ufd); /* bpf_map_do_batch() guarantees ufd is valid */ for (cp = 0; cp < max_count; cp++) { err = -EFAULT; if (copy_from_user(key, keys + cp * map->key_size, @@ -1640,7 +1637,7 @@ int generic_map_update_batch(struct bpf_map *map, copy_from_user(value, values + cp * value_size, value_size)) break; - err = bpf_map_update_value(map, f, key, value, + err = bpf_map_update_value(map, map_file, key, value, attr->batch.elem_flags); if (err) @@ -1653,7 +1650,6 @@ int generic_map_update_batch(struct bpf_map *map, kvfree(value); kvfree(key); - fdput(f); return err; } @@ -4446,13 +4442,13 @@ put_file: #define BPF_MAP_BATCH_LAST_FIELD batch.flags -#define BPF_DO_BATCH(fn) \ +#define BPF_DO_BATCH(fn, ...) \ do { \ if (!fn) { \ err = -ENOTSUPP; \ goto err_put; \ } \ - err = fn(map, attr, uattr); \ + err = fn(__VA_ARGS__); \ } while (0) static int bpf_map_do_batch(const union bpf_attr *attr, @@ -4486,13 +4482,13 @@ static int bpf_map_do_batch(const union bpf_attr *attr, } if (cmd == BPF_MAP_LOOKUP_BATCH) - BPF_DO_BATCH(map->ops->map_lookup_batch); + BPF_DO_BATCH(map->ops->map_lookup_batch, map, attr, uattr); else if (cmd == BPF_MAP_LOOKUP_AND_DELETE_BATCH) - BPF_DO_BATCH(map->ops->map_lookup_and_delete_batch); + BPF_DO_BATCH(map->ops->map_lookup_and_delete_batch, map, attr, uattr); else if (cmd == BPF_MAP_UPDATE_BATCH) - BPF_DO_BATCH(map->ops->map_update_batch); + BPF_DO_BATCH(map->ops->map_update_batch, map, f.file, attr, uattr); else - BPF_DO_BATCH(map->ops->map_delete_batch); + BPF_DO_BATCH(map->ops->map_delete_batch, map, attr, uattr); err_put: if (has_write) bpf_map_write_active_dec(map); From c4525f05ca3ca2795fc626252fb1c1cbb310111b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= Date: Tue, 15 Nov 2022 19:20:50 +0100 Subject: [PATCH 024/101] selftests/bpf: Explicitly pass RESOLVE_BTFIDS to sub-make MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When cross-compiling selftests/bpf, the resolve_btfids binary end up in a different directory, than the regular resolve_btfids builds. Populate RESOLVE_BTFIDS for sub-make, so it can find the binary. Signed-off-by: Björn Töpel Signed-off-by: Andrii Nakryiko Acked-by: Jiri Olsa Link: https://lore.kernel.org/bpf/20221115182051.582962-1-bjorn@kernel.org --- tools/testing/selftests/bpf/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index f3cd17026ee5..aa4e29315f4a 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -201,7 +201,7 @@ $(OUTPUT)/sign-file: ../../../../scripts/sign-file.c $(OUTPUT)/bpf_testmod.ko: $(VMLINUX_BTF) $(wildcard bpf_testmod/Makefile bpf_testmod/*.[ch]) $(call msg,MOD,,$@) $(Q)$(RM) bpf_testmod/bpf_testmod.ko # force re-compilation - $(Q)$(MAKE) $(submake_extras) -C bpf_testmod + $(Q)$(MAKE) $(submake_extras) RESOLVE_BTFIDS=$(RESOLVE_BTFIDS) -C bpf_testmod $(Q)cp bpf_testmod/bpf_testmod.ko $@ DEFAULT_BPFTOOL := $(HOST_SCRATCH_DIR)/sbin/bpftool From 98b2afc8a67f651ed01fc7d5a7e2528e63dd4e08 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= Date: Tue, 15 Nov 2022 19:20:51 +0100 Subject: [PATCH 025/101] selftests/bpf: Pass target triple to get_sys_includes macro MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When cross-compiling [1], the get_sys_includes make macro should use the target system include path, and not the build hosts system include path. Make clang honor the CROSS_COMPILE triple. [1] e.g. "ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- make" Signed-off-by: Björn Töpel Signed-off-by: Andrii Nakryiko Tested-by: Anders Roxell Link: https://lore.kernel.org/bpf/20221115182051.582962-2-bjorn@kernel.org --- tools/testing/selftests/bpf/Makefile | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index aa4e29315f4a..6a0f043dc410 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -310,9 +310,9 @@ $(RESOLVE_BTFIDS): $(HOST_BPFOBJ) | $(HOST_BUILD_DIR)/resolve_btfids \ # Use '-idirafter': Don't interfere with include mechanics except where the # build would have failed anyways. define get_sys_includes -$(shell $(1) -v -E - &1 \ +$(shell $(1) $(2) -v -E - &1 \ | sed -n '/<...> search starts here:/,/End of search list./{ s| \(/.*\)|-idirafter \1|p }') \ -$(shell $(1) -dM -E - Date: Fri, 18 Nov 2022 07:25:51 +0530 Subject: [PATCH 026/101] bpf: Fix early return in map_check_btf Instead of returning directly with -EOPNOTSUPP for the timer case, we need to free the btf_record before returning to userspace. Fixes: db559117828d ("bpf: Consolidate spin_lock, timer management into btf_record") Reported-by: Dan Carpenter Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-2-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/syscall.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index b078965999e6..8eff51a63af6 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1010,7 +1010,7 @@ static int map_check_btf(struct bpf_map *map, const struct btf *btf, if (map->map_type != BPF_MAP_TYPE_HASH && map->map_type != BPF_MAP_TYPE_LRU_HASH && map->map_type != BPF_MAP_TYPE_ARRAY) { - return -EOPNOTSUPP; + ret = -EOPNOTSUPP; goto free_map_tab; } break; From d7f5ef653c3dd0c0d649cae6ef2708053bb1fb2b Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:25:52 +0530 Subject: [PATCH 027/101] bpf: Do btf_record_free outside map_free callback Since the commit being fixed, we now miss freeing btf_record for local storage maps which will have a btf_record populated in case they have bpf_spin_lock element. This was missed because I made the choice of offloading the job to free kptr_off_tab (now btf_record) to the map_free callback when adding support for kptrs. Revisiting the reason for this decision, there is the possibility that the btf_record gets used inside map_free callback (e.g. in case of maps embedding kptrs) to iterate over them and free them, hence doing it before the map_free callback would be leaking special field memory, and do invalid memory access. The btf_record keeps module references which is critical to ensure the dtor call made for referenced kptr is safe to do. If doing it after map_free callback, the map area is already freed, so we cannot access bpf_map structure anymore. To fix this and prevent such lapses in future, move bpf_map_free_record out of the map_free callback, and do it after map_free by remembering the btf_record pointer. There is no need to access bpf_map structure in that case, and we can avoid missing this case when support for new map types is added for other special fields. Since a btf_record and its btf_field_offs are used together, for consistency delay freeing of field_offs as well. While not a problem right now, a lot of code assumes that either both record and field_offs are set or none at once. Note that in case of map of maps (outer maps), inner_map_meta->record is only used during verification, not to free fields in map value, hence we simply keep the bpf_map_free_record call as is in bpf_map_meta_free and never touch map->inner_map_meta in bpf_map_free_deferred. Add a comment making note of these details. Fixes: db559117828d ("bpf: Consolidate spin_lock, timer management into btf_record") Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-3-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/arraymap.c | 1 - kernel/bpf/hashtab.c | 1 - kernel/bpf/syscall.c | 18 ++++++++++++++---- 3 files changed, 14 insertions(+), 6 deletions(-) diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index 672eb17ac421..484706959556 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -430,7 +430,6 @@ static void array_map_free(struct bpf_map *map) for (i = 0; i < array->map.max_entries; i++) bpf_obj_free_fields(map->record, array_map_elem_ptr(array, i)); } - bpf_map_free_record(map); } if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY) diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index 50d254cd0709..5aa2b5525f79 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -1511,7 +1511,6 @@ static void htab_map_free(struct bpf_map *map) prealloc_destroy(htab); } - bpf_map_free_record(map); free_percpu(htab->extra_elems); bpf_map_area_free(htab->buckets); bpf_mem_alloc_destroy(&htab->pcpu_ma); diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 8eff51a63af6..4c20dcbc6526 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -659,14 +659,24 @@ void bpf_obj_free_fields(const struct btf_record *rec, void *obj) static void bpf_map_free_deferred(struct work_struct *work) { struct bpf_map *map = container_of(work, struct bpf_map, work); + struct btf_field_offs *foffs = map->field_offs; + struct btf_record *rec = map->record; security_bpf_map_free(map); - kfree(map->field_offs); bpf_map_release_memcg(map); - /* implementation dependent freeing, map_free callback also does - * bpf_map_free_record, if needed. - */ + /* implementation dependent freeing */ map->ops->map_free(map); + /* Delay freeing of field_offs and btf_record for maps, as map_free + * callback usually needs access to them. It is better to do it here + * than require each callback to do the free itself manually. + * + * Note that the btf_record stashed in map->inner_map_meta->record was + * already freed using the map_free callback for map in map case which + * eventually calls bpf_map_free_meta, since inner_map_meta is only a + * template bpf_map struct used during verification. + */ + kfree(foffs); + btf_record_free(rec); } static void bpf_map_put_uref(struct bpf_map *map) From d48995723c9a1c4896206be382c72d722accbfbc Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:25:53 +0530 Subject: [PATCH 028/101] bpf: Free inner_map_meta when btf_record_dup fails Whenever btf_record_dup fails, we must free inner_map_meta that was allocated before. This fixes a memory leak (in case of errors) during inner map creation. Fixes: aa3496accc41 ("bpf: Refactor kptr_off_tab into btf_record") Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-4-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/map_in_map.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/map_in_map.c b/kernel/bpf/map_in_map.c index 8ca0cca39d49..a423130a8720 100644 --- a/kernel/bpf/map_in_map.c +++ b/kernel/bpf/map_in_map.c @@ -52,12 +52,14 @@ struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd) inner_map_meta->max_entries = inner_map->max_entries; inner_map_meta->record = btf_record_dup(inner_map->record); if (IS_ERR(inner_map_meta->record)) { + struct bpf_map *err_ptr = ERR_CAST(inner_map_meta->record); /* btf_record_dup returns NULL or valid pointer in case of * invalid/empty/valid, but ERR_PTR in case of errors. During * equality NULL or IS_ERR is equivalent. */ + kfree(inner_map_meta); fdput(f); - return ERR_CAST(inner_map_meta->record); + return err_ptr; } if (inner_map->btf) { btf_get(inner_map->btf); From f73e601aafb2ad9f2b2012b969f86f4a41141a7d Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:25:54 +0530 Subject: [PATCH 029/101] bpf: Populate field_offs for inner_map_meta Far too much code simply assumes that both btf_record and btf_field_offs are set to valid pointers together, or both are unset. They go together hand in hand as btf_record describes the special fields and btf_field_offs is compact representation for runtime copying/zeroing. It is very difficult to make this clear in the code when the only exception to this universal invariant is inner_map_meta which is used as reg->map_ptr in the verifier. This is simply a bug waiting to happen, as in verifier context we cannot easily distinguish if PTR_TO_MAP_VALUE is coming from an inner map, and if we ever end up using field_offs for any reason in the future, we will silently ignore the special fields for inner map case (as NULL is not an error but unset field_offs). Hence, simply copy field_offs from inner map together with btf_record. While at it, refactor code to unwind properly on errors with gotos. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-5-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/map_in_map.c | 44 ++++++++++++++++++++++++++++++----------- 1 file changed, 32 insertions(+), 12 deletions(-) diff --git a/kernel/bpf/map_in_map.c b/kernel/bpf/map_in_map.c index a423130a8720..fae6a6c33e2d 100644 --- a/kernel/bpf/map_in_map.c +++ b/kernel/bpf/map_in_map.c @@ -12,6 +12,7 @@ struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd) struct bpf_map *inner_map, *inner_map_meta; u32 inner_map_meta_size; struct fd f; + int ret; f = fdget(inner_map_ufd); inner_map = __bpf_map_get(f); @@ -20,18 +21,18 @@ struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd) /* Does not support >1 level map-in-map */ if (inner_map->inner_map_meta) { - fdput(f); - return ERR_PTR(-EINVAL); + ret = -EINVAL; + goto put; } if (!inner_map->ops->map_meta_equal) { - fdput(f); - return ERR_PTR(-ENOTSUPP); + ret = -ENOTSUPP; + goto put; } if (btf_record_has_field(inner_map->record, BPF_SPIN_LOCK)) { - fdput(f); - return ERR_PTR(-ENOTSUPP); + ret = -ENOTSUPP; + goto put; } inner_map_meta_size = sizeof(*inner_map_meta); @@ -41,8 +42,8 @@ struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd) inner_map_meta = kzalloc(inner_map_meta_size, GFP_USER); if (!inner_map_meta) { - fdput(f); - return ERR_PTR(-ENOMEM); + ret = -ENOMEM; + goto put; } inner_map_meta->map_type = inner_map->map_type; @@ -50,16 +51,27 @@ struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd) inner_map_meta->value_size = inner_map->value_size; inner_map_meta->map_flags = inner_map->map_flags; inner_map_meta->max_entries = inner_map->max_entries; + inner_map_meta->record = btf_record_dup(inner_map->record); if (IS_ERR(inner_map_meta->record)) { - struct bpf_map *err_ptr = ERR_CAST(inner_map_meta->record); /* btf_record_dup returns NULL or valid pointer in case of * invalid/empty/valid, but ERR_PTR in case of errors. During * equality NULL or IS_ERR is equivalent. */ - kfree(inner_map_meta); - fdput(f); - return err_ptr; + ret = PTR_ERR(inner_map_meta->record); + goto free; + } + if (inner_map_meta->record) { + struct btf_field_offs *field_offs; + /* If btf_record is !IS_ERR_OR_NULL, then field_offs is always + * valid. + */ + field_offs = kmemdup(inner_map->field_offs, sizeof(*inner_map->field_offs), GFP_KERNEL | __GFP_NOWARN); + if (!field_offs) { + ret = -ENOMEM; + goto free_rec; + } + inner_map_meta->field_offs = field_offs; } if (inner_map->btf) { btf_get(inner_map->btf); @@ -76,10 +88,18 @@ struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd) fdput(f); return inner_map_meta; +free_rec: + btf_record_free(inner_map_meta->record); +free: + kfree(inner_map_meta); +put: + fdput(f); + return ERR_PTR(ret); } void bpf_map_meta_free(struct bpf_map *map_meta) { + kfree(map_meta->field_offs); bpf_map_free_record(map_meta); btf_put(map_meta->btf); kfree(map_meta); From 282de143ead96a5d53331e946f31c977b4610a74 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:25:55 +0530 Subject: [PATCH 030/101] bpf: Introduce allocated objects support Introduce support for representing pointers to objects allocated by the BPF program, i.e. PTR_TO_BTF_ID that point to a type in program BTF. This is indicated by the presence of MEM_ALLOC type flag in reg->type to avoid having to check btf_is_kernel when trying to match argument types in helpers. Whenever walking such types, any pointers being walked will always yield a SCALAR instead of pointer. In the future we might permit kptr inside such allocated objects (either kernel or program allocated), and it will then form a PTR_TO_BTF_ID of the respective type. For now, such allocated objects will always be referenced in verifier context, hence ref_obj_id == 0 for them is a bug. It is allowed to write to such objects, as long fields that are special are not touched (support for which will be added in subsequent patches). Note that once such a pointer is marked PTR_UNTRUSTED, it is no longer allowed to write to it. No PROBE_MEM handling is therefore done for loads into this type unless PTR_UNTRUSTED is part of the register type, since they can never be in an undefined state, and their lifetime will always be valid. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-6-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/linux/bpf.h | 11 +++++++++++ kernel/bpf/btf.c | 5 +++++ kernel/bpf/verifier.c | 25 +++++++++++++++++++++++-- 3 files changed, 39 insertions(+), 2 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index e60a5c052473..7440c20c4192 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -525,6 +525,11 @@ enum bpf_type_flag { /* Size is known at compile time. */ MEM_FIXED_SIZE = BIT(10 + BPF_BASE_TYPE_BITS), + /* MEM is of an allocated object of type in program BTF. This is used to + * tag PTR_TO_BTF_ID allocated using bpf_obj_new. + */ + MEM_ALLOC = BIT(11 + BPF_BASE_TYPE_BITS), + __BPF_TYPE_FLAG_MAX, __BPF_TYPE_LAST_FLAG = __BPF_TYPE_FLAG_MAX - 1, }; @@ -2792,4 +2797,10 @@ struct bpf_key { bool has_ref; }; #endif /* CONFIG_KEYS */ + +static inline bool type_is_alloc(u32 type) +{ + return type & MEM_ALLOC; +} + #endif /* _LINUX_BPF_H */ diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 875355ff3718..9a596f430558 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -6034,6 +6034,11 @@ int btf_struct_access(struct bpf_verifier_log *log, switch (err) { case WALK_PTR: + /* For local types, the destination register cannot + * become a pointer again. + */ + if (type_is_alloc(reg->type)) + return SCALAR_VALUE; /* If we found the pointer or scalar on t+off, * we're done. */ diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 0312d9ce292f..49e08c1c2c61 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4687,14 +4687,27 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env, return -EACCES; } - if (env->ops->btf_struct_access) { + if (env->ops->btf_struct_access && !type_is_alloc(reg->type)) { + if (!btf_is_kernel(reg->btf)) { + verbose(env, "verifier internal error: reg->btf must be kernel btf\n"); + return -EFAULT; + } ret = env->ops->btf_struct_access(&env->log, reg, off, size, atype, &btf_id, &flag); } else { - if (atype != BPF_READ) { + /* Writes are permitted with default btf_struct_access for + * program allocated objects (which always have ref_obj_id > 0), + * but not for untrusted PTR_TO_BTF_ID | MEM_ALLOC. + */ + if (atype != BPF_READ && reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) { verbose(env, "only read is supported\n"); return -EACCES; } + if (type_is_alloc(reg->type) && !reg->ref_obj_id) { + verbose(env, "verifier internal error: ref_obj_id for allocated object must be non-zero\n"); + return -EFAULT; + } + ret = btf_struct_access(&env->log, reg, off, size, atype, &btf_id, &flag); } @@ -5973,6 +5986,7 @@ int check_func_arg_reg_off(struct bpf_verifier_env *env, * fixed offset. */ case PTR_TO_BTF_ID: + case PTR_TO_BTF_ID | MEM_ALLOC: /* When referenced PTR_TO_BTF_ID is passed to release function, * it's fixed offset must be 0. In the other cases, fixed offset * can be non-zero. @@ -13690,6 +13704,13 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) break; case PTR_TO_BTF_ID: case PTR_TO_BTF_ID | PTR_UNTRUSTED: + /* PTR_TO_BTF_ID | MEM_ALLOC always has a valid lifetime, unlike + * PTR_TO_BTF_ID, and an active ref_obj_id, but the same cannot + * be said once it is marked PTR_UNTRUSTED, hence we must handle + * any faults for loads into such types. BPF_WRITE is disallowed + * for this case. + */ + case PTR_TO_BTF_ID | MEM_ALLOC | PTR_UNTRUSTED: if (type == BPF_READ) { insn->code = BPF_LDX | BPF_PROBE_MEM | BPF_SIZE((insn)->code); From 8ffa5cc142137a59d6a10eb5273fa2ba5dcd4947 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:25:56 +0530 Subject: [PATCH 031/101] bpf: Recognize lock and list fields in allocated objects Allow specifying bpf_spin_lock, bpf_list_head, bpf_list_node fields in a allocated object. Also update btf_struct_access to reject direct access to these special fields. A bpf_list_head allows implementing map-in-map style use cases, where an allocated object with bpf_list_head is linked into a list in a map value. This would require embedding a bpf_list_node, support for which is also included. The bpf_spin_lock is used to protect the bpf_list_head and other data. While we strictly don't require to hold a bpf_spin_lock while touching the bpf_list_head in such objects, as when have access to it, we have complete ownership of the object, the locking constraint is still kept and may be conditionally lifted in the future. Note that the specification of such types can be done just like map values, e.g.: struct bar { struct bpf_list_node node; }; struct foo { struct bpf_spin_lock lock; struct bpf_list_head head __contains(bar, node); struct bpf_list_node node; }; struct map_value { struct bpf_spin_lock lock; struct bpf_list_head head __contains(foo, node); }; To recognize such types in user BTF, we build a btf_struct_metas array of metadata items corresponding to each BTF ID. This is done once during the btf_parse stage to avoid having to do it each time during the verification process's requirement to inspect the metadata. Moreover, the computed metadata needs to be passed to some helpers in future patches which requires allocating them and storing them in the BTF that is pinned by the program itself, so that valid access can be assumed to such data during program runtime. A key thing to note is that once a btf_struct_meta is available for a type, both the btf_record and btf_field_offs should be available. It is critical that btf_field_offs is available in case special fields are present, as we extensively rely on special fields being zeroed out in map values and allocated objects in later patches. The code ensures that by bailing out in case of errors and ensuring both are available together. If the record is not available, the special fields won't be recognized, so not having both is also fine (in terms of being a verification error and not a runtime bug). Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/linux/bpf.h | 7 ++ include/linux/btf.h | 35 ++++++++ kernel/bpf/btf.c | 197 +++++++++++++++++++++++++++++++++++++++---- kernel/bpf/syscall.c | 4 + 4 files changed, 225 insertions(+), 18 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 7440c20c4192..eb6ea53fa5a2 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -177,6 +177,7 @@ enum btf_field_type { BPF_KPTR_REF = (1 << 3), BPF_KPTR = BPF_KPTR_UNREF | BPF_KPTR_REF, BPF_LIST_HEAD = (1 << 4), + BPF_LIST_NODE = (1 << 5), }; struct btf_field_kptr { @@ -277,6 +278,8 @@ static inline const char *btf_field_type_name(enum btf_field_type type) return "kptr"; case BPF_LIST_HEAD: return "bpf_list_head"; + case BPF_LIST_NODE: + return "bpf_list_node"; default: WARN_ON_ONCE(1); return "unknown"; @@ -295,6 +298,8 @@ static inline u32 btf_field_type_size(enum btf_field_type type) return sizeof(u64); case BPF_LIST_HEAD: return sizeof(struct bpf_list_head); + case BPF_LIST_NODE: + return sizeof(struct bpf_list_node); default: WARN_ON_ONCE(1); return 0; @@ -313,6 +318,8 @@ static inline u32 btf_field_type_align(enum btf_field_type type) return __alignof__(u64); case BPF_LIST_HEAD: return __alignof__(struct bpf_list_head); + case BPF_LIST_NODE: + return __alignof__(struct bpf_list_node); default: WARN_ON_ONCE(1); return 0; diff --git a/include/linux/btf.h b/include/linux/btf.h index d80345fa566b..a01a8da20021 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -6,6 +6,8 @@ #include #include +#include +#include #include #include @@ -78,6 +80,17 @@ struct btf_id_dtor_kfunc { u32 kfunc_btf_id; }; +struct btf_struct_meta { + u32 btf_id; + struct btf_record *record; + struct btf_field_offs *field_offs; +}; + +struct btf_struct_metas { + u32 cnt; + struct btf_struct_meta types[]; +}; + typedef void (*btf_dtor_kfunc_t)(void *); extern const struct file_operations btf_fops; @@ -408,6 +421,23 @@ static inline struct btf_param *btf_params(const struct btf_type *t) return (struct btf_param *)(t + 1); } +static inline int btf_id_cmp_func(const void *a, const void *b) +{ + const int *pa = a, *pb = b; + + return *pa - *pb; +} + +static inline bool btf_id_set_contains(const struct btf_id_set *set, u32 id) +{ + return bsearch(&id, set->ids, set->cnt, sizeof(u32), btf_id_cmp_func) != NULL; +} + +static inline void *btf_id_set8_contains(const struct btf_id_set8 *set, u32 id) +{ + return bsearch(&id, set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func); +} + #ifdef CONFIG_BPF_SYSCALL struct bpf_prog; @@ -423,6 +453,7 @@ int register_btf_kfunc_id_set(enum bpf_prog_type prog_type, s32 btf_find_dtor_kfunc(struct btf *btf, u32 btf_id); int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_cnt, struct module *owner); +struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id); #else static inline const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id) @@ -454,6 +485,10 @@ static inline int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dt { return 0; } +static inline struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id) +{ + return NULL; +} #endif static inline bool btf_type_is_struct_ptr(struct btf *btf, const struct btf_type *t) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 9a596f430558..a04e10477567 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -237,6 +237,7 @@ struct btf { struct rcu_head rcu; struct btf_kfunc_set_tab *kfunc_set_tab; struct btf_id_dtor_kfunc_tab *dtor_kfunc_tab; + struct btf_struct_metas *struct_meta_tab; /* split BTF support */ struct btf *base_btf; @@ -1642,8 +1643,30 @@ static void btf_free_dtor_kfunc_tab(struct btf *btf) btf->dtor_kfunc_tab = NULL; } +static void btf_struct_metas_free(struct btf_struct_metas *tab) +{ + int i; + + if (!tab) + return; + for (i = 0; i < tab->cnt; i++) { + btf_record_free(tab->types[i].record); + kfree(tab->types[i].field_offs); + } + kfree(tab); +} + +static void btf_free_struct_meta_tab(struct btf *btf) +{ + struct btf_struct_metas *tab = btf->struct_meta_tab; + + btf_struct_metas_free(tab); + btf->struct_meta_tab = NULL; +} + static void btf_free(struct btf *btf) { + btf_free_struct_meta_tab(btf); btf_free_dtor_kfunc_tab(btf); btf_free_kfunc_set_tab(btf); kvfree(btf->types); @@ -3353,6 +3376,12 @@ static int btf_get_field_type(const char *name, u32 field_mask, u32 *seen_mask, goto end; } } + if (field_mask & BPF_LIST_NODE) { + if (!strcmp(name, "bpf_list_node")) { + type = BPF_LIST_NODE; + goto end; + } + } /* Only return BPF_KPTR when all other types with matchable names fail */ if (field_mask & BPF_KPTR) { type = BPF_KPTR_REF; @@ -3396,6 +3425,7 @@ static int btf_find_struct_field(const struct btf *btf, switch (field_type) { case BPF_SPIN_LOCK: case BPF_TIMER: + case BPF_LIST_NODE: ret = btf_find_struct(btf, member_type, off, sz, field_type, idx < info_cnt ? &info[idx] : &tmp); if (ret < 0) @@ -3456,6 +3486,7 @@ static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t, switch (field_type) { case BPF_SPIN_LOCK: case BPF_TIMER: + case BPF_LIST_NODE: ret = btf_find_struct(btf, var_type, off, sz, field_type, idx < info_cnt ? &info[idx] : &tmp); if (ret < 0) @@ -3671,6 +3702,8 @@ struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type if (ret < 0) goto end; break; + case BPF_LIST_NODE: + break; default: ret = -EFAULT; goto end; @@ -5141,6 +5174,119 @@ static int btf_parse_hdr(struct btf_verifier_env *env) return btf_check_sec_info(env, btf_data_size); } +static const char *alloc_obj_fields[] = { + "bpf_spin_lock", + "bpf_list_head", + "bpf_list_node", +}; + +static struct btf_struct_metas * +btf_parse_struct_metas(struct bpf_verifier_log *log, struct btf *btf) +{ + union { + struct btf_id_set set; + struct { + u32 _cnt; + u32 _ids[ARRAY_SIZE(alloc_obj_fields)]; + } _arr; + } aof; + struct btf_struct_metas *tab = NULL; + int i, n, id, ret; + + BUILD_BUG_ON(offsetof(struct btf_id_set, cnt) != 0); + BUILD_BUG_ON(sizeof(struct btf_id_set) != sizeof(u32)); + + memset(&aof, 0, sizeof(aof)); + for (i = 0; i < ARRAY_SIZE(alloc_obj_fields); i++) { + /* Try to find whether this special type exists in user BTF, and + * if so remember its ID so we can easily find it among members + * of structs that we iterate in the next loop. + */ + id = btf_find_by_name_kind(btf, alloc_obj_fields[i], BTF_KIND_STRUCT); + if (id < 0) + continue; + aof.set.ids[aof.set.cnt++] = id; + } + + if (!aof.set.cnt) + return NULL; + sort(&aof.set.ids, aof.set.cnt, sizeof(aof.set.ids[0]), btf_id_cmp_func, NULL); + + n = btf_nr_types(btf); + for (i = 1; i < n; i++) { + struct btf_struct_metas *new_tab; + const struct btf_member *member; + struct btf_field_offs *foffs; + struct btf_struct_meta *type; + struct btf_record *record; + const struct btf_type *t; + int j, tab_cnt; + + t = btf_type_by_id(btf, i); + if (!t) { + ret = -EINVAL; + goto free; + } + if (!__btf_type_is_struct(t)) + continue; + + cond_resched(); + + for_each_member(j, t, member) { + if (btf_id_set_contains(&aof.set, member->type)) + goto parse; + } + continue; + parse: + tab_cnt = tab ? tab->cnt : 0; + new_tab = krealloc(tab, offsetof(struct btf_struct_metas, types[tab_cnt + 1]), + GFP_KERNEL | __GFP_NOWARN); + if (!new_tab) { + ret = -ENOMEM; + goto free; + } + if (!tab) + new_tab->cnt = 0; + tab = new_tab; + + type = &tab->types[tab->cnt]; + type->btf_id = i; + record = btf_parse_fields(btf, t, BPF_SPIN_LOCK | BPF_LIST_HEAD | BPF_LIST_NODE, t->size); + /* The record cannot be unset, treat it as an error if so */ + if (IS_ERR_OR_NULL(record)) { + ret = PTR_ERR_OR_ZERO(record) ?: -EFAULT; + goto free; + } + foffs = btf_parse_field_offs(record); + /* We need the field_offs to be valid for a valid record, + * either both should be set or both should be unset. + */ + if (IS_ERR_OR_NULL(foffs)) { + btf_record_free(record); + ret = -EFAULT; + goto free; + } + type->record = record; + type->field_offs = foffs; + tab->cnt++; + } + return tab; +free: + btf_struct_metas_free(tab); + return ERR_PTR(ret); +} + +struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id) +{ + struct btf_struct_metas *tab; + + BUILD_BUG_ON(offsetof(struct btf_struct_meta, btf_id) != 0); + tab = btf->struct_meta_tab; + if (!tab) + return NULL; + return bsearch(&btf_id, tab->types, tab->cnt, sizeof(tab->types[0]), btf_id_cmp_func); +} + static int btf_check_type_tags(struct btf_verifier_env *env, struct btf *btf, int start_id) { @@ -5191,6 +5337,7 @@ static int btf_check_type_tags(struct btf_verifier_env *env, static struct btf *btf_parse(bpfptr_t btf_data, u32 btf_data_size, u32 log_level, char __user *log_ubuf, u32 log_size) { + struct btf_struct_metas *struct_meta_tab; struct btf_verifier_env *env = NULL; struct bpf_verifier_log *log; struct btf *btf = NULL; @@ -5259,15 +5406,24 @@ static struct btf *btf_parse(bpfptr_t btf_data, u32 btf_data_size, if (err) goto errout; + struct_meta_tab = btf_parse_struct_metas(log, btf); + if (IS_ERR(struct_meta_tab)) { + err = PTR_ERR(struct_meta_tab); + goto errout; + } + btf->struct_meta_tab = struct_meta_tab; + if (log->level && bpf_verifier_log_full(log)) { err = -ENOSPC; - goto errout; + goto errout_meta; } btf_verifier_env_free(env); refcount_set(&btf->refcnt, 1); return btf; +errout_meta: + btf_free_struct_meta_tab(btf); errout: btf_verifier_env_free(env); if (btf) @@ -6028,6 +6184,28 @@ int btf_struct_access(struct bpf_verifier_log *log, u32 id = reg->btf_id; int err; + while (type_is_alloc(reg->type)) { + struct btf_struct_meta *meta; + struct btf_record *rec; + int i; + + meta = btf_find_struct_meta(btf, id); + if (!meta) + break; + rec = meta->record; + for (i = 0; i < rec->cnt; i++) { + struct btf_field *field = &rec->fields[i]; + u32 offset = field->offset; + if (off < offset + btf_field_type_size(field->type) && offset < off + size) { + bpf_log(log, + "direct access to %s is disallowed\n", + btf_field_type_name(field->type)); + return -EACCES; + } + } + break; + } + t = btf_type_by_id(btf, id); do { err = btf_struct_walk(log, btf, t, off, size, &id, &tmp_flag); @@ -7269,23 +7447,6 @@ bool btf_is_module(const struct btf *btf) return btf->kernel_btf && strcmp(btf->name, "vmlinux") != 0; } -static int btf_id_cmp_func(const void *a, const void *b) -{ - const int *pa = a, *pb = b; - - return *pa - *pb; -} - -bool btf_id_set_contains(const struct btf_id_set *set, u32 id) -{ - return bsearch(&id, set->ids, set->cnt, sizeof(u32), btf_id_cmp_func) != NULL; -} - -static void *btf_id_set8_contains(const struct btf_id_set8 *set, u32 id) -{ - return bsearch(&id, set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func); -} - enum { BTF_MODULE_F_LIVE = (1 << 0), }; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 4c20dcbc6526..56ae97d490f4 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -537,6 +537,7 @@ void btf_record_free(struct btf_record *rec) btf_put(rec->fields[i].kptr.btf); break; case BPF_LIST_HEAD: + case BPF_LIST_NODE: /* Nothing to release for bpf_list_head */ break; default: @@ -582,6 +583,7 @@ struct btf_record *btf_record_dup(const struct btf_record *rec) } break; case BPF_LIST_HEAD: + case BPF_LIST_NODE: /* Nothing to acquire for bpf_list_head */ break; default: @@ -648,6 +650,8 @@ void bpf_obj_free_fields(const struct btf_record *rec, void *obj) continue; bpf_list_head_free(field, field_ptr, obj + rec->spin_lock_off); break; + case BPF_LIST_NODE: + break; default: WARN_ON_ONCE(1); continue; From 865ce09a49d79d2b2c1d980f4c05ffc0b3517bdc Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:25:57 +0530 Subject: [PATCH 032/101] bpf: Verify ownership relationships for user BTF types Ensure that there can be no ownership cycles among different types by way of having owning objects that can hold some other type as their element. For instance, a map value can only hold allocated objects, but these are allowed to have another bpf_list_head. To prevent unbounded recursion while freeing resources, elements of bpf_list_head in local kptrs can never have a bpf_list_head which are part of list in a map value. Later patches will verify this by having dedicated BTF selftests. Also, to make runtime destruction easier, once btf_struct_metas is fully populated, we can stash the metadata of the value type directly in the metadata of the list_head fields, as that allows easier access to the value type's layout to destruct it at runtime from the btf_field entry of the list head itself. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-8-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/linux/bpf.h | 1 + include/linux/btf.h | 1 + kernel/bpf/btf.c | 71 ++++++++++++++++++++++++++++++++++++++++++++ kernel/bpf/syscall.c | 4 +++ 4 files changed, 77 insertions(+) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index eb6ea53fa5a2..323985a39ece 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -191,6 +191,7 @@ struct btf_field_list_head { struct btf *btf; u32 value_btf_id; u32 node_offset; + struct btf_record *value_rec; }; struct btf_field { diff --git a/include/linux/btf.h b/include/linux/btf.h index a01a8da20021..42d8f3730a8d 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -178,6 +178,7 @@ int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t); int btf_find_timer(const struct btf *btf, const struct btf_type *t); struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type *t, u32 field_mask, u32 value_size); +int btf_check_and_fixup_fields(const struct btf *btf, struct btf_record *rec); struct btf_field_offs *btf_parse_field_offs(struct btf_record *rec); bool btf_type_is_void(const struct btf_type *t); s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind); diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index a04e10477567..91aa9c96621f 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -3723,6 +3723,67 @@ end: return ERR_PTR(ret); } +int btf_check_and_fixup_fields(const struct btf *btf, struct btf_record *rec) +{ + int i; + + /* There are two owning types, kptr_ref and bpf_list_head. The former + * only supports storing kernel types, which can never store references + * to program allocated local types, atleast not yet. Hence we only need + * to ensure that bpf_list_head ownership does not form cycles. + */ + if (IS_ERR_OR_NULL(rec) || !(rec->field_mask & BPF_LIST_HEAD)) + return 0; + for (i = 0; i < rec->cnt; i++) { + struct btf_struct_meta *meta; + u32 btf_id; + + if (!(rec->fields[i].type & BPF_LIST_HEAD)) + continue; + btf_id = rec->fields[i].list_head.value_btf_id; + meta = btf_find_struct_meta(btf, btf_id); + if (!meta) + return -EFAULT; + rec->fields[i].list_head.value_rec = meta->record; + + if (!(rec->field_mask & BPF_LIST_NODE)) + continue; + + /* We need to ensure ownership acyclicity among all types. The + * proper way to do it would be to topologically sort all BTF + * IDs based on the ownership edges, since there can be multiple + * bpf_list_head in a type. Instead, we use the following + * reasoning: + * + * - A type can only be owned by another type in user BTF if it + * has a bpf_list_node. + * - A type can only _own_ another type in user BTF if it has a + * bpf_list_head. + * + * We ensure that if a type has both bpf_list_head and + * bpf_list_node, its element types cannot be owning types. + * + * To ensure acyclicity: + * + * When A only has bpf_list_head, ownership chain can be: + * A -> B -> C + * Where: + * - B has both bpf_list_head and bpf_list_node. + * - C only has bpf_list_node. + * + * When A has both bpf_list_head and bpf_list_node, some other + * type already owns it in the BTF domain, hence it can not own + * another owning type through any of the bpf_list_head edges. + * A -> B + * Where: + * - B only has bpf_list_node. + */ + if (meta->record->field_mask & BPF_LIST_HEAD) + return -ELOOP; + } + return 0; +} + static int btf_field_offs_cmp(const void *_a, const void *_b, const void *priv) { const u32 a = *(const u32 *)_a; @@ -5413,6 +5474,16 @@ static struct btf *btf_parse(bpfptr_t btf_data, u32 btf_data_size, } btf->struct_meta_tab = struct_meta_tab; + if (struct_meta_tab) { + int i; + + for (i = 0; i < struct_meta_tab->cnt; i++) { + err = btf_check_and_fixup_fields(btf, struct_meta_tab->types[i].record); + if (err < 0) + goto errout_meta; + } + } + if (log->level && bpf_verifier_log_full(log)) { err = -ENOSPC; goto errout_meta; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 56ae97d490f4..6140cbc3ed8a 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1054,6 +1054,10 @@ static int map_check_btf(struct bpf_map *map, const struct btf *btf, } } + ret = btf_check_and_fixup_fields(btf, map->record); + if (ret < 0) + goto free_map_tab; + if (map->ops->map_check_btf) { ret = map->ops->map_check_btf(map, btf, key_type, value_type); if (ret < 0) From 4e814da0d59917c6d758a80e63e79b5ee212cf11 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:25:58 +0530 Subject: [PATCH 033/101] bpf: Allow locking bpf_spin_lock in allocated objects Allow locking a bpf_spin_lock in an allocated object, in addition to already supported map value pointers. The handling is similar to that of map values, by just preserving the reg->id of PTR_TO_BTF_ID | MEM_ALLOC as well, and adjusting process_spin_lock to work with them and remember the id in verifier state. Refactor the existing process_spin_lock to work with PTR_TO_BTF_ID | MEM_ALLOC in addition to PTR_TO_MAP_VALUE. We need to update the reg_may_point_to_spin_lock which is used in mark_ptr_or_null_reg to preserve reg->id, that will be used in env->cur_state->active_spin_lock to remember the currently held spin lock. Also update the comment describing bpf_spin_lock implementation details to also talk about PTR_TO_BTF_ID | MEM_ALLOC type. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-9-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/helpers.c | 2 + kernel/bpf/verifier.c | 92 +++++++++++++++++++++++++++++++------------ 2 files changed, 68 insertions(+), 26 deletions(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 7bc71995f17c..5bc0b9f0f306 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -336,6 +336,7 @@ const struct bpf_func_proto bpf_spin_lock_proto = { .gpl_only = false, .ret_type = RET_VOID, .arg1_type = ARG_PTR_TO_SPIN_LOCK, + .arg1_btf_id = BPF_PTR_POISON, }; static inline void __bpf_spin_unlock_irqrestore(struct bpf_spin_lock *lock) @@ -358,6 +359,7 @@ const struct bpf_func_proto bpf_spin_unlock_proto = { .gpl_only = false, .ret_type = RET_VOID, .arg1_type = ARG_PTR_TO_SPIN_LOCK, + .arg1_btf_id = BPF_PTR_POISON, }; void copy_map_value_locked(struct bpf_map *map, void *dst, void *src, diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 49e08c1c2c61..19467dda5dd9 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -451,10 +451,24 @@ static bool reg_type_not_null(enum bpf_reg_type type) type == PTR_TO_SOCK_COMMON; } +static struct btf_record *reg_btf_record(const struct bpf_reg_state *reg) +{ + struct btf_record *rec = NULL; + struct btf_struct_meta *meta; + + if (reg->type == PTR_TO_MAP_VALUE) { + rec = reg->map_ptr->record; + } else if (reg->type == (PTR_TO_BTF_ID | MEM_ALLOC)) { + meta = btf_find_struct_meta(reg->btf, reg->btf_id); + if (meta) + rec = meta->record; + } + return rec; +} + static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg) { - return reg->type == PTR_TO_MAP_VALUE && - btf_record_has_field(reg->map_ptr->record, BPF_SPIN_LOCK); + return btf_record_has_field(reg_btf_record(reg), BPF_SPIN_LOCK); } static bool type_is_rdonly_mem(u32 type) @@ -5564,23 +5578,26 @@ int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state } /* Implementation details: - * bpf_map_lookup returns PTR_TO_MAP_VALUE_OR_NULL + * bpf_map_lookup returns PTR_TO_MAP_VALUE_OR_NULL. + * bpf_obj_new returns PTR_TO_BTF_ID | MEM_ALLOC | PTR_MAYBE_NULL. * Two bpf_map_lookups (even with the same key) will have different reg->id. - * For traditional PTR_TO_MAP_VALUE the verifier clears reg->id after - * value_or_null->value transition, since the verifier only cares about - * the range of access to valid map value pointer and doesn't care about actual - * address of the map element. + * Two separate bpf_obj_new will also have different reg->id. + * For traditional PTR_TO_MAP_VALUE or PTR_TO_BTF_ID | MEM_ALLOC, the verifier + * clears reg->id after value_or_null->value transition, since the verifier only + * cares about the range of access to valid map value pointer and doesn't care + * about actual address of the map element. * For maps with 'struct bpf_spin_lock' inside map value the verifier keeps * reg->id > 0 after value_or_null->value transition. By doing so * two bpf_map_lookups will be considered two different pointers that - * point to different bpf_spin_locks. + * point to different bpf_spin_locks. Likewise for pointers to allocated objects + * returned from bpf_obj_new. * The verifier allows taking only one bpf_spin_lock at a time to avoid * dead-locks. * Since only one bpf_spin_lock is allowed the checks are simpler than * reg_is_refcounted() logic. The verifier needs to remember only * one spin_lock instead of array of acquired_refs. - * cur_state->active_spin_lock remembers which map value element got locked - * and clears it after bpf_spin_unlock. + * cur_state->active_spin_lock remembers which map value element or allocated + * object got locked and clears it after bpf_spin_unlock. */ static int process_spin_lock(struct bpf_verifier_env *env, int regno, bool is_lock) @@ -5588,8 +5605,10 @@ static int process_spin_lock(struct bpf_verifier_env *env, int regno, struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; struct bpf_verifier_state *cur = env->cur_state; bool is_const = tnum_is_const(reg->var_off); - struct bpf_map *map = reg->map_ptr; u64 val = reg->var_off.value; + struct bpf_map *map = NULL; + struct btf *btf = NULL; + struct btf_record *rec; if (!is_const) { verbose(env, @@ -5597,19 +5616,27 @@ static int process_spin_lock(struct bpf_verifier_env *env, int regno, regno); return -EINVAL; } - if (!map->btf) { - verbose(env, - "map '%s' has to have BTF in order to use bpf_spin_lock\n", - map->name); + if (reg->type == PTR_TO_MAP_VALUE) { + map = reg->map_ptr; + if (!map->btf) { + verbose(env, + "map '%s' has to have BTF in order to use bpf_spin_lock\n", + map->name); + return -EINVAL; + } + } else { + btf = reg->btf; + } + + rec = reg_btf_record(reg); + if (!btf_record_has_field(rec, BPF_SPIN_LOCK)) { + verbose(env, "%s '%s' has no valid bpf_spin_lock\n", map ? "map" : "local", + map ? map->name : "kptr"); return -EINVAL; } - if (!btf_record_has_field(map->record, BPF_SPIN_LOCK)) { - verbose(env, "map '%s' has no valid bpf_spin_lock\n", map->name); - return -EINVAL; - } - if (map->record->spin_lock_off != val + reg->off) { + if (rec->spin_lock_off != val + reg->off) { verbose(env, "off %lld doesn't point to 'struct bpf_spin_lock' that is at %d\n", - val + reg->off, map->record->spin_lock_off); + val + reg->off, rec->spin_lock_off); return -EINVAL; } if (is_lock) { @@ -5815,13 +5842,19 @@ static const struct bpf_reg_types int_ptr_types = { }, }; +static const struct bpf_reg_types spin_lock_types = { + .types = { + PTR_TO_MAP_VALUE, + PTR_TO_BTF_ID | MEM_ALLOC, + } +}; + static const struct bpf_reg_types fullsock_types = { .types = { PTR_TO_SOCKET } }; static const struct bpf_reg_types scalar_types = { .types = { SCALAR_VALUE } }; static const struct bpf_reg_types context_types = { .types = { PTR_TO_CTX } }; static const struct bpf_reg_types ringbuf_mem_types = { .types = { PTR_TO_MEM | MEM_RINGBUF } }; static const struct bpf_reg_types const_map_ptr_types = { .types = { CONST_PTR_TO_MAP } }; static const struct bpf_reg_types btf_ptr_types = { .types = { PTR_TO_BTF_ID } }; -static const struct bpf_reg_types spin_lock_types = { .types = { PTR_TO_MAP_VALUE } }; static const struct bpf_reg_types percpu_btf_ptr_types = { .types = { PTR_TO_BTF_ID | MEM_PERCPU } }; static const struct bpf_reg_types func_ptr_types = { .types = { PTR_TO_FUNC } }; static const struct bpf_reg_types stack_ptr_types = { .types = { PTR_TO_STACK } }; @@ -5946,6 +5979,11 @@ found: return -EACCES; } } + } else if (type_is_alloc(reg->type)) { + if (meta->func_id != BPF_FUNC_spin_lock && meta->func_id != BPF_FUNC_spin_unlock) { + verbose(env, "verifier internal error: unimplemented handling of MEM_ALLOC\n"); + return -EFAULT; + } } return 0; @@ -6062,7 +6100,8 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, goto skip_type_check; /* arg_btf_id and arg_size are in a union. */ - if (base_type(arg_type) == ARG_PTR_TO_BTF_ID) + if (base_type(arg_type) == ARG_PTR_TO_BTF_ID || + base_type(arg_type) == ARG_PTR_TO_SPIN_LOCK) arg_btf_id = fn->arg_btf_id[arg]; err = check_reg_type(env, regno, arg_type, arg_btf_id, meta); @@ -6680,9 +6719,10 @@ static bool check_btf_id_ok(const struct bpf_func_proto *fn) int i; for (i = 0; i < ARRAY_SIZE(fn->arg_type); i++) { - if (base_type(fn->arg_type[i]) == ARG_PTR_TO_BTF_ID && !fn->arg_btf_id[i]) - return false; - + if (base_type(fn->arg_type[i]) == ARG_PTR_TO_BTF_ID) + return !!fn->arg_btf_id[i]; + if (base_type(fn->arg_type[i]) == ARG_PTR_TO_SPIN_LOCK) + return fn->arg_btf_id[i] == BPF_PTR_POISON; if (base_type(fn->arg_type[i]) != ARG_PTR_TO_BTF_ID && fn->arg_btf_id[i] && /* arg_btf_id and arg_size are in a union. */ (base_type(fn->arg_type[i]) != ARG_PTR_TO_MEM || From d0d78c1df9b1dbfb5e172de473561ce09d5e9d39 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:25:59 +0530 Subject: [PATCH 034/101] bpf: Allow locking bpf_spin_lock global variables Global variables reside in maps accessible using direct_value_addr callbacks, so giving each load instruction's rewrite a unique reg->id disallows us from holding locks which are global. The reason for preserving reg->id as a unique value for registers that may point to spin lock is that two separate lookups are treated as two separate memory regions, and any possible aliasing is ignored for the purposes of spin lock correctness. This is not great especially for the global variable case, which are served from maps that have max_entries == 1, i.e. they always lead to map values pointing into the same map value. So refactor the active_spin_lock into a 'active_lock' structure which represents the lock identity, and instead of the reg->id, remember two fields, a pointer and the reg->id. The pointer will store reg->map_ptr or reg->btf. It's only necessary to distinguish for the id == 0 case of global variables, but always setting the pointer to a non-NULL value and using the pointer to check whether the lock is held simplifies code in the verifier. This is generic enough to allow it for global variables, map lookups, and allocated objects at the same time. Note that while whether a lock is held can be answered by just comparing active_lock.ptr to NULL, to determine whether the register is pointing to the same held lock requires comparing _both_ ptr and id. Finally, as a result of this refactoring, pseudo load instructions are not given a unique reg->id, as they are doing lookup for the same map value (max_entries is never greater than 1). Essentially, we consider that the tuple of (ptr, id) will always be unique for any kind of argument to bpf_spin_{lock,unlock}. Note that this can be extended in the future to also remember offset used for locking, so that we can introduce multiple bpf_spin_lock fields in the same allocation. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-10-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/linux/bpf_verifier.h | 16 +++++++++++++- kernel/bpf/verifier.c | 41 ++++++++++++++++++++++++------------ 2 files changed, 43 insertions(+), 14 deletions(-) diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 1a32baa78ce2..1db2b4dc7009 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -323,7 +323,21 @@ struct bpf_verifier_state { u32 branches; u32 insn_idx; u32 curframe; - u32 active_spin_lock; + /* For every reg representing a map value or allocated object pointer, + * we consider the tuple of (ptr, id) for them to be unique in verifier + * context and conside them to not alias each other for the purposes of + * tracking lock state. + */ + struct { + /* This can either be reg->map_ptr or reg->btf. If ptr is NULL, + * there's no active lock held, and other fields have no + * meaning. If non-NULL, it indicates that a lock is held and + * id member has the reg->id of the register which can be >= 0. + */ + void *ptr; + /* This will be reg->id */ + u32 id; + } active_lock; bool speculative; /* first and last insn idx of this verifier state */ diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 19467dda5dd9..c8f3abe9b08e 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1221,7 +1221,8 @@ static int copy_verifier_state(struct bpf_verifier_state *dst_state, } dst_state->speculative = src->speculative; dst_state->curframe = src->curframe; - dst_state->active_spin_lock = src->active_spin_lock; + dst_state->active_lock.ptr = src->active_lock.ptr; + dst_state->active_lock.id = src->active_lock.id; dst_state->branches = src->branches; dst_state->parent = src->parent; dst_state->first_insn_idx = src->first_insn_idx; @@ -5596,7 +5597,7 @@ int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state * Since only one bpf_spin_lock is allowed the checks are simpler than * reg_is_refcounted() logic. The verifier needs to remember only * one spin_lock instead of array of acquired_refs. - * cur_state->active_spin_lock remembers which map value element or allocated + * cur_state->active_lock remembers which map value element or allocated * object got locked and clears it after bpf_spin_unlock. */ static int process_spin_lock(struct bpf_verifier_env *env, int regno, @@ -5640,22 +5641,35 @@ static int process_spin_lock(struct bpf_verifier_env *env, int regno, return -EINVAL; } if (is_lock) { - if (cur->active_spin_lock) { + if (cur->active_lock.ptr) { verbose(env, "Locking two bpf_spin_locks are not allowed\n"); return -EINVAL; } - cur->active_spin_lock = reg->id; + if (map) + cur->active_lock.ptr = map; + else + cur->active_lock.ptr = btf; + cur->active_lock.id = reg->id; } else { - if (!cur->active_spin_lock) { + void *ptr; + + if (map) + ptr = map; + else + ptr = btf; + + if (!cur->active_lock.ptr) { verbose(env, "bpf_spin_unlock without taking a lock\n"); return -EINVAL; } - if (cur->active_spin_lock != reg->id) { + if (cur->active_lock.ptr != ptr || + cur->active_lock.id != reg->id) { verbose(env, "bpf_spin_unlock of different lock\n"); return -EINVAL; } - cur->active_spin_lock = 0; + cur->active_lock.ptr = NULL; + cur->active_lock.id = 0; } return 0; } @@ -10617,8 +10631,8 @@ static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn) insn->src_reg == BPF_PSEUDO_MAP_IDX_VALUE) { dst_reg->type = PTR_TO_MAP_VALUE; dst_reg->off = aux->map_off; - if (btf_record_has_field(map->record, BPF_SPIN_LOCK)) - dst_reg->id = ++env->id_gen; + WARN_ON_ONCE(map->max_entries != 1); + /* We want reg->id to be same (0) as map_value is not distinct */ } else if (insn->src_reg == BPF_PSEUDO_MAP_FD || insn->src_reg == BPF_PSEUDO_MAP_IDX) { dst_reg->type = CONST_PTR_TO_MAP; @@ -10696,7 +10710,7 @@ static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn) return err; } - if (env->cur_state->active_spin_lock) { + if (env->cur_state->active_lock.ptr) { verbose(env, "BPF_LD_[ABS|IND] cannot be used inside bpf_spin_lock-ed region\n"); return -EINVAL; } @@ -11962,7 +11976,8 @@ static bool states_equal(struct bpf_verifier_env *env, if (old->speculative && !cur->speculative) return false; - if (old->active_spin_lock != cur->active_spin_lock) + if (old->active_lock.ptr != cur->active_lock.ptr || + old->active_lock.id != cur->active_lock.id) return false; /* for states to be equal callsites have to be the same @@ -12607,7 +12622,7 @@ static int do_check(struct bpf_verifier_env *env) return -EINVAL; } - if (env->cur_state->active_spin_lock && + if (env->cur_state->active_lock.ptr && (insn->src_reg == BPF_PSEUDO_CALL || insn->imm != BPF_FUNC_spin_unlock)) { verbose(env, "function calls are not allowed while holding a lock\n"); @@ -12644,7 +12659,7 @@ static int do_check(struct bpf_verifier_env *env) return -EINVAL; } - if (env->cur_state->active_spin_lock) { + if (env->cur_state->active_lock.ptr) { verbose(env, "bpf_spin_unlock is missing\n"); return -EINVAL; } From b7ff97925b55a0603a7c215305df4b43ab632948 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:26:00 +0530 Subject: [PATCH 035/101] bpf: Allow locking bpf_spin_lock in inner map values There is no need to restrict users from locking bpf_spin_lock in map values of inner maps. Each inner map lookup gets a unique reg->id assigned to the returned PTR_TO_MAP_VALUE which will be preserved after the NULL check. Distinct lookups into different inner map get unique IDs, and distinct lookups into same inner map also get unique IDs. Hence, lift the restriction by removing the check return -ENOTSUPP in map_in_map.c. Later commits will add comprehensive test cases to ensure that invalid cases are rejected. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-11-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/map_in_map.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/kernel/bpf/map_in_map.c b/kernel/bpf/map_in_map.c index fae6a6c33e2d..7cce2047c6ef 100644 --- a/kernel/bpf/map_in_map.c +++ b/kernel/bpf/map_in_map.c @@ -30,11 +30,6 @@ struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd) goto put; } - if (btf_record_has_field(inner_map->record, BPF_SPIN_LOCK)) { - ret = -ENOTSUPP; - goto put; - } - inner_map_meta_size = sizeof(*inner_map_meta); /* In some cases verifier needs to access beyond just base map. */ if (inner_map->ops == &array_map_ops) From 00b85860feb809852af9a88cb4ca8766d7dff6a3 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:26:01 +0530 Subject: [PATCH 036/101] bpf: Rewrite kfunc argument handling As we continue to add more features, argument types, kfunc flags, and different extensions to kfuncs, the code to verify the correctness of the kfunc prototype wrt the passed in registers has become ad-hoc and ugly to read. To make life easier, and make a very clear split between different stages of argument processing, move all the code into verifier.c and refactor into easier to read helpers and functions. This also makes sharing code within the verifier easier with kfunc argument processing. This will be more and more useful in later patches as we are now moving to implement very core BPF helpers as kfuncs, to keep them experimental before baking into UAPI. Remove all kfunc related bits now from btf_check_func_arg_match, as users have been converted away to refactored kfunc argument handling. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-12-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/linux/bpf.h | 11 - include/linux/bpf_verifier.h | 2 - include/linux/btf.h | 31 +- kernel/bpf/btf.c | 380 +----------- kernel/bpf/verifier.c | 545 +++++++++++++++++- .../bpf/prog_tests/kfunc_dynptr_param.c | 2 +- tools/testing/selftests/bpf/verifier/calls.c | 2 +- .../selftests/bpf/verifier/ref_tracking.c | 4 +- 8 files changed, 573 insertions(+), 404 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 323985a39ece..0a74df731eb8 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2109,22 +2109,11 @@ int btf_distill_func_proto(struct bpf_verifier_log *log, const char *func_name, struct btf_func_model *m); -struct bpf_kfunc_arg_meta { - u64 r0_size; - bool r0_rdonly; - int ref_obj_id; - u32 flags; -}; - struct bpf_reg_state; int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog, struct bpf_reg_state *regs); int btf_check_subprog_call(struct bpf_verifier_env *env, int subprog, struct bpf_reg_state *regs); -int btf_check_kfunc_arg_match(struct bpf_verifier_env *env, - const struct btf *btf, u32 func_id, - struct bpf_reg_state *regs, - struct bpf_kfunc_arg_meta *meta); int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog, struct bpf_reg_state *reg); int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog, diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 1db2b4dc7009..fb146b0ce006 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -603,8 +603,6 @@ int check_ptr_off_reg(struct bpf_verifier_env *env, int check_func_arg_reg_off(struct bpf_verifier_env *env, const struct bpf_reg_state *reg, int regno, enum bpf_arg_type arg_type); -int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg, - u32 regno); int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg, u32 regno, u32 mem_size); bool is_dynptr_reg_valid_init(struct bpf_verifier_env *env, diff --git a/include/linux/btf.h b/include/linux/btf.h index 42d8f3730a8d..d5b26380a60f 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -338,6 +338,16 @@ static inline bool btf_type_is_struct(const struct btf_type *t) return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION; } +static inline bool __btf_type_is_struct(const struct btf_type *t) +{ + return BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT; +} + +static inline bool btf_type_is_array(const struct btf_type *t) +{ + return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY; +} + static inline u16 btf_type_vlen(const struct btf_type *t) { return BTF_INFO_VLEN(t->info); @@ -439,9 +449,10 @@ static inline void *btf_id_set8_contains(const struct btf_id_set8 *set, u32 id) return bsearch(&id, set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func); } -#ifdef CONFIG_BPF_SYSCALL struct bpf_prog; +struct bpf_verifier_log; +#ifdef CONFIG_BPF_SYSCALL const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id); const char *btf_name_by_offset(const struct btf *btf, u32 offset); struct btf *btf_parse_vmlinux(void); @@ -455,6 +466,12 @@ s32 btf_find_dtor_kfunc(struct btf *btf, u32 btf_id); int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_cnt, struct module *owner); struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id); +const struct btf_member * +btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf, + const struct btf_type *t, enum bpf_prog_type prog_type, + int arg); +bool btf_types_are_same(const struct btf *btf1, u32 id1, + const struct btf *btf2, u32 id2); #else static inline const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id) @@ -490,6 +507,18 @@ static inline struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf { return NULL; } +static inline const struct btf_member * +btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf, + const struct btf_type *t, enum bpf_prog_type prog_type, + int arg) +{ + return NULL; +} +static inline bool btf_types_are_same(const struct btf *btf1, u32 id1, + const struct btf *btf2, u32 id2) +{ + return false; +} #endif static inline bool btf_type_is_struct_ptr(struct btf *btf, const struct btf_type *t) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 91aa9c96621f..4dcda4ae48c1 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -478,16 +478,6 @@ static bool btf_type_nosize_or_null(const struct btf_type *t) return !t || btf_type_nosize(t); } -static bool __btf_type_is_struct(const struct btf_type *t) -{ - return BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT; -} - -static bool btf_type_is_array(const struct btf_type *t) -{ - return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY; -} - static bool btf_type_is_datasec(const struct btf_type *t) { return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC; @@ -5536,7 +5526,7 @@ static u8 bpf_ctx_convert_map[] = { #undef BPF_MAP_TYPE #undef BPF_LINK_TYPE -static const struct btf_member * +const struct btf_member * btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf, const struct btf_type *t, enum bpf_prog_type prog_type, int arg) @@ -6322,8 +6312,8 @@ int btf_struct_access(struct bpf_verifier_log *log, * end up with two different module BTFs, but IDs point to the common type in * vmlinux BTF. */ -static bool btf_types_are_same(const struct btf *btf1, u32 id1, - const struct btf *btf2, u32 id2) +bool btf_types_are_same(const struct btf *btf1, u32 id1, + const struct btf *btf2, u32 id2) { if (id1 != id2) return false; @@ -6605,122 +6595,19 @@ int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *pr return btf_check_func_type_match(log, btf1, t1, btf2, t2); } -static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = { -#ifdef CONFIG_NET - [PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK], - [PTR_TO_SOCK_COMMON] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON], - [PTR_TO_TCP_SOCK] = &btf_sock_ids[BTF_SOCK_TYPE_TCP], -#endif -}; - -/* Returns true if struct is composed of scalars, 4 levels of nesting allowed */ -static bool __btf_type_is_scalar_struct(struct bpf_verifier_log *log, - const struct btf *btf, - const struct btf_type *t, int rec) -{ - const struct btf_type *member_type; - const struct btf_member *member; - u32 i; - - if (!btf_type_is_struct(t)) - return false; - - for_each_member(i, t, member) { - const struct btf_array *array; - - member_type = btf_type_skip_modifiers(btf, member->type, NULL); - if (btf_type_is_struct(member_type)) { - if (rec >= 3) { - bpf_log(log, "max struct nesting depth exceeded\n"); - return false; - } - if (!__btf_type_is_scalar_struct(log, btf, member_type, rec + 1)) - return false; - continue; - } - if (btf_type_is_array(member_type)) { - array = btf_type_array(member_type); - if (!array->nelems) - return false; - member_type = btf_type_skip_modifiers(btf, array->type, NULL); - if (!btf_type_is_scalar(member_type)) - return false; - continue; - } - if (!btf_type_is_scalar(member_type)) - return false; - } - return true; -} - -static bool is_kfunc_arg_mem_size(const struct btf *btf, - const struct btf_param *arg, - const struct bpf_reg_state *reg) -{ - int len, sfx_len = sizeof("__sz") - 1; - const struct btf_type *t; - const char *param_name; - - t = btf_type_skip_modifiers(btf, arg->type, NULL); - if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE) - return false; - - /* In the future, this can be ported to use BTF tagging */ - param_name = btf_name_by_offset(btf, arg->name_off); - if (str_is_empty(param_name)) - return false; - len = strlen(param_name); - if (len < sfx_len) - return false; - param_name += len - sfx_len; - if (strncmp(param_name, "__sz", sfx_len)) - return false; - - return true; -} - -static bool btf_is_kfunc_arg_mem_size(const struct btf *btf, - const struct btf_param *arg, - const struct bpf_reg_state *reg, - const char *name) -{ - int len, target_len = strlen(name); - const struct btf_type *t; - const char *param_name; - - t = btf_type_skip_modifiers(btf, arg->type, NULL); - if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE) - return false; - - param_name = btf_name_by_offset(btf, arg->name_off); - if (str_is_empty(param_name)) - return false; - len = strlen(param_name); - if (len != target_len) - return false; - if (strcmp(param_name, name)) - return false; - - return true; -} - static int btf_check_func_arg_match(struct bpf_verifier_env *env, const struct btf *btf, u32 func_id, struct bpf_reg_state *regs, bool ptr_to_mem_ok, - struct bpf_kfunc_arg_meta *kfunc_meta, bool processing_call) { enum bpf_prog_type prog_type = resolve_prog_type(env->prog); - bool rel = false, kptr_get = false, trusted_args = false; - bool sleepable = false; struct bpf_verifier_log *log = &env->log; - u32 i, nargs, ref_id, ref_obj_id = 0; - bool is_kfunc = btf_is_kernel(btf); const char *func_name, *ref_tname; const struct btf_type *t, *ref_t; const struct btf_param *args; - int ref_regno = 0, ret; + u32 i, nargs, ref_id; + int ret; t = btf_type_by_id(btf, func_id); if (!t || !btf_type_is_func(t)) { @@ -6746,14 +6633,6 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, return -EINVAL; } - if (is_kfunc && kfunc_meta) { - /* Only kfunc can be release func */ - rel = kfunc_meta->flags & KF_RELEASE; - kptr_get = kfunc_meta->flags & KF_KPTR_GET; - trusted_args = kfunc_meta->flags & KF_TRUSTED_ARGS; - sleepable = kfunc_meta->flags & KF_SLEEPABLE; - } - /* check that BTF function arguments match actual types that the * verifier sees. */ @@ -6761,42 +6640,9 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, enum bpf_arg_type arg_type = ARG_DONTCARE; u32 regno = i + 1; struct bpf_reg_state *reg = ®s[regno]; - bool obj_ptr = false; t = btf_type_skip_modifiers(btf, args[i].type, NULL); if (btf_type_is_scalar(t)) { - if (is_kfunc && kfunc_meta) { - bool is_buf_size = false; - - /* check for any const scalar parameter of name "rdonly_buf_size" - * or "rdwr_buf_size" - */ - if (btf_is_kfunc_arg_mem_size(btf, &args[i], reg, - "rdonly_buf_size")) { - kfunc_meta->r0_rdonly = true; - is_buf_size = true; - } else if (btf_is_kfunc_arg_mem_size(btf, &args[i], reg, - "rdwr_buf_size")) - is_buf_size = true; - - if (is_buf_size) { - if (kfunc_meta->r0_size) { - bpf_log(log, "2 or more rdonly/rdwr_buf_size parameters for kfunc"); - return -EINVAL; - } - - if (!tnum_is_const(reg->var_off)) { - bpf_log(log, "R%d is not a const\n", regno); - return -EINVAL; - } - - kfunc_meta->r0_size = reg->var_off.value; - ret = mark_chain_precision(env, regno); - if (ret) - return ret; - } - } - if (reg->type == SCALAR_VALUE) continue; bpf_log(log, "R%d is not a scalar\n", regno); @@ -6809,88 +6655,14 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, return -EINVAL; } - /* These register types have special constraints wrt ref_obj_id - * and offset checks. The rest of trusted args don't. - */ - obj_ptr = reg->type == PTR_TO_CTX || reg->type == PTR_TO_BTF_ID || - reg2btf_ids[base_type(reg->type)]; - - /* Check if argument must be a referenced pointer, args + i has - * been verified to be a pointer (after skipping modifiers). - * PTR_TO_CTX is ok without having non-zero ref_obj_id. - */ - if (is_kfunc && trusted_args && (obj_ptr && reg->type != PTR_TO_CTX) && !reg->ref_obj_id) { - bpf_log(log, "R%d must be referenced\n", regno); - return -EINVAL; - } - ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id); ref_tname = btf_name_by_offset(btf, ref_t->name_off); - /* Trusted args have the same offset checks as release arguments */ - if ((trusted_args && obj_ptr) || (rel && reg->ref_obj_id)) - arg_type |= OBJ_RELEASE; ret = check_func_arg_reg_off(env, reg, regno, arg_type); if (ret < 0) return ret; - if (is_kfunc && reg->ref_obj_id) { - /* Ensure only one argument is referenced PTR_TO_BTF_ID */ - if (ref_obj_id) { - bpf_log(log, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n", - regno, reg->ref_obj_id, ref_obj_id); - return -EFAULT; - } - ref_regno = regno; - ref_obj_id = reg->ref_obj_id; - } - - /* kptr_get is only true for kfunc */ - if (i == 0 && kptr_get) { - struct btf_field *kptr_field; - - if (reg->type != PTR_TO_MAP_VALUE) { - bpf_log(log, "arg#0 expected pointer to map value\n"); - return -EINVAL; - } - - /* check_func_arg_reg_off allows var_off for - * PTR_TO_MAP_VALUE, but we need fixed offset to find - * off_desc. - */ - if (!tnum_is_const(reg->var_off)) { - bpf_log(log, "arg#0 must have constant offset\n"); - return -EINVAL; - } - - kptr_field = btf_record_find(reg->map_ptr->record, reg->off + reg->var_off.value, BPF_KPTR); - if (!kptr_field || kptr_field->type != BPF_KPTR_REF) { - bpf_log(log, "arg#0 no referenced kptr at map value offset=%llu\n", - reg->off + reg->var_off.value); - return -EINVAL; - } - - if (!btf_type_is_ptr(ref_t)) { - bpf_log(log, "arg#0 BTF type must be a double pointer\n"); - return -EINVAL; - } - - ref_t = btf_type_skip_modifiers(btf, ref_t->type, &ref_id); - ref_tname = btf_name_by_offset(btf, ref_t->name_off); - - if (!btf_type_is_struct(ref_t)) { - bpf_log(log, "kernel function %s args#%d pointer type %s %s is not supported\n", - func_name, i, btf_type_str(ref_t), ref_tname); - return -EINVAL; - } - if (!btf_struct_ids_match(log, btf, ref_id, 0, kptr_field->kptr.btf, - kptr_field->kptr.btf_id, true)) { - bpf_log(log, "kernel function %s args#%d expected pointer to %s %s\n", - func_name, i, btf_type_str(ref_t), ref_tname); - return -EINVAL; - } - /* rest of the arguments can be anything, like normal kfunc */ - } else if (btf_get_prog_ctx_type(log, btf, t, prog_type, i)) { + if (btf_get_prog_ctx_type(log, btf, t, prog_type, i)) { /* If function expects ctx type in BTF check that caller * is passing PTR_TO_CTX. */ @@ -6900,109 +6672,10 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, i, btf_type_str(t)); return -EINVAL; } - } else if (is_kfunc && (reg->type == PTR_TO_BTF_ID || - (reg2btf_ids[base_type(reg->type)] && !type_flag(reg->type)))) { - const struct btf_type *reg_ref_t; - const struct btf *reg_btf; - const char *reg_ref_tname; - u32 reg_ref_id; - - if (!btf_type_is_struct(ref_t)) { - bpf_log(log, "kernel function %s args#%d pointer type %s %s is not supported\n", - func_name, i, btf_type_str(ref_t), - ref_tname); - return -EINVAL; - } - - if (reg->type == PTR_TO_BTF_ID) { - reg_btf = reg->btf; - reg_ref_id = reg->btf_id; - } else { - reg_btf = btf_vmlinux; - reg_ref_id = *reg2btf_ids[base_type(reg->type)]; - } - - reg_ref_t = btf_type_skip_modifiers(reg_btf, reg_ref_id, - ®_ref_id); - reg_ref_tname = btf_name_by_offset(reg_btf, - reg_ref_t->name_off); - if (!btf_struct_ids_match(log, reg_btf, reg_ref_id, - reg->off, btf, ref_id, - trusted_args || (rel && reg->ref_obj_id))) { - bpf_log(log, "kernel function %s args#%d expected pointer to %s %s but R%d has a pointer to %s %s\n", - func_name, i, - btf_type_str(ref_t), ref_tname, - regno, btf_type_str(reg_ref_t), - reg_ref_tname); - return -EINVAL; - } } else if (ptr_to_mem_ok && processing_call) { const struct btf_type *resolve_ret; u32 type_size; - if (is_kfunc) { - bool arg_mem_size = i + 1 < nargs && is_kfunc_arg_mem_size(btf, &args[i + 1], ®s[regno + 1]); - bool arg_dynptr = btf_type_is_struct(ref_t) && - !strcmp(ref_tname, - stringify_struct(bpf_dynptr_kern)); - - /* Permit pointer to mem, but only when argument - * type is pointer to scalar, or struct composed - * (recursively) of scalars. - * When arg_mem_size is true, the pointer can be - * void *. - * Also permit initialized local dynamic pointers. - */ - if (!btf_type_is_scalar(ref_t) && - !__btf_type_is_scalar_struct(log, btf, ref_t, 0) && - !arg_dynptr && - (arg_mem_size ? !btf_type_is_void(ref_t) : 1)) { - bpf_log(log, - "arg#%d pointer type %s %s must point to %sscalar, or struct with scalar\n", - i, btf_type_str(ref_t), ref_tname, arg_mem_size ? "void, " : ""); - return -EINVAL; - } - - if (arg_dynptr) { - if (reg->type != PTR_TO_STACK) { - bpf_log(log, "arg#%d pointer type %s %s not to stack\n", - i, btf_type_str(ref_t), - ref_tname); - return -EINVAL; - } - - if (!is_dynptr_reg_valid_init(env, reg)) { - bpf_log(log, - "arg#%d pointer type %s %s must be valid and initialized\n", - i, btf_type_str(ref_t), - ref_tname); - return -EINVAL; - } - - if (!is_dynptr_type_expected(env, reg, - ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_LOCAL)) { - bpf_log(log, - "arg#%d pointer type %s %s points to unsupported dynamic pointer type\n", - i, btf_type_str(ref_t), - ref_tname); - return -EINVAL; - } - - continue; - } - - /* Check for mem, len pair */ - if (arg_mem_size) { - if (check_kfunc_mem_size_reg(env, ®s[regno + 1], regno + 1)) { - bpf_log(log, "arg#%d arg#%d memory, len pair leads to invalid memory access\n", - i, i + 1); - return -EINVAL; - } - i++; - continue; - } - } - resolve_ret = btf_resolve_size(btf, ref_t, &type_size); if (IS_ERR(resolve_ret)) { bpf_log(log, @@ -7015,36 +6688,13 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, if (check_mem_reg(env, reg, regno, type_size)) return -EINVAL; } else { - bpf_log(log, "reg type unsupported for arg#%d %sfunction %s#%d\n", i, - is_kfunc ? "kernel " : "", func_name, func_id); + bpf_log(log, "reg type unsupported for arg#%d function %s#%d\n", i, + func_name, func_id); return -EINVAL; } } - /* Either both are set, or neither */ - WARN_ON_ONCE((ref_obj_id && !ref_regno) || (!ref_obj_id && ref_regno)); - /* We already made sure ref_obj_id is set only for one argument. We do - * allow (!rel && ref_obj_id), so that passing such referenced - * PTR_TO_BTF_ID to other kfuncs works. Note that rel is only true when - * is_kfunc is true. - */ - if (rel && !ref_obj_id) { - bpf_log(log, "release kernel function %s expects refcounted PTR_TO_BTF_ID\n", - func_name); - return -EINVAL; - } - - if (sleepable && !env->prog->aux->sleepable) { - bpf_log(log, "kernel function %s is sleepable but the program is not\n", - func_name); - return -EINVAL; - } - - if (kfunc_meta && ref_obj_id) - kfunc_meta->ref_obj_id = ref_obj_id; - - /* returns argument register number > 0 in case of reference release kfunc */ - return rel ? ref_regno : 0; + return 0; } /* Compare BTF of a function declaration with given bpf_reg_state. @@ -7074,7 +6724,7 @@ int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog, return -EINVAL; is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL; - err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, NULL, false); + err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, false); /* Compiler optimizations can remove arguments from static functions * or mismatched type can be passed into a global function. @@ -7117,7 +6767,7 @@ int btf_check_subprog_call(struct bpf_verifier_env *env, int subprog, return -EINVAL; is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL; - err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, NULL, true); + err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, true); /* Compiler optimizations can remove arguments from static functions * or mismatched type can be passed into a global function. @@ -7128,14 +6778,6 @@ int btf_check_subprog_call(struct bpf_verifier_env *env, int subprog, return err; } -int btf_check_kfunc_arg_match(struct bpf_verifier_env *env, - const struct btf *btf, u32 func_id, - struct bpf_reg_state *regs, - struct bpf_kfunc_arg_meta *meta) -{ - return btf_check_func_arg_match(env, btf, func_id, regs, true, meta, true); -} - /* Convert BTF of a function into bpf_reg_state if possible * Returns: * EFAULT - there is a verifier bug. Abort verification. diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index c8f3abe9b08e..7d7a91c54709 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5550,8 +5550,8 @@ int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg, return err; } -int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg, - u32 regno) +static int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg, + u32 regno) { struct bpf_reg_state *mem_reg = &cur_regs(env)[regno - 1]; bool may_be_null = type_may_be_null(mem_reg->type); @@ -7863,19 +7863,517 @@ static void mark_btf_func_reg_size(struct bpf_verifier_env *env, u32 regno, } } +struct bpf_kfunc_call_arg_meta { + /* In parameters */ + struct btf *btf; + u32 func_id; + u32 kfunc_flags; + const struct btf_type *func_proto; + const char *func_name; + /* Out parameters */ + u32 ref_obj_id; + u8 release_regno; + bool r0_rdonly; + u64 r0_size; +}; + +static bool is_kfunc_acquire(struct bpf_kfunc_call_arg_meta *meta) +{ + return meta->kfunc_flags & KF_ACQUIRE; +} + +static bool is_kfunc_ret_null(struct bpf_kfunc_call_arg_meta *meta) +{ + return meta->kfunc_flags & KF_RET_NULL; +} + +static bool is_kfunc_release(struct bpf_kfunc_call_arg_meta *meta) +{ + return meta->kfunc_flags & KF_RELEASE; +} + +static bool is_kfunc_trusted_args(struct bpf_kfunc_call_arg_meta *meta) +{ + return meta->kfunc_flags & KF_TRUSTED_ARGS; +} + +static bool is_kfunc_sleepable(struct bpf_kfunc_call_arg_meta *meta) +{ + return meta->kfunc_flags & KF_SLEEPABLE; +} + +static bool is_kfunc_destructive(struct bpf_kfunc_call_arg_meta *meta) +{ + return meta->kfunc_flags & KF_DESTRUCTIVE; +} + +static bool is_kfunc_arg_kptr_get(struct bpf_kfunc_call_arg_meta *meta, int arg) +{ + return arg == 0 && (meta->kfunc_flags & KF_KPTR_GET); +} + +static bool is_kfunc_arg_mem_size(const struct btf *btf, + const struct btf_param *arg, + const struct bpf_reg_state *reg) +{ + int len, sfx_len = sizeof("__sz") - 1; + const struct btf_type *t; + const char *param_name; + + t = btf_type_skip_modifiers(btf, arg->type, NULL); + if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE) + return false; + + /* In the future, this can be ported to use BTF tagging */ + param_name = btf_name_by_offset(btf, arg->name_off); + if (str_is_empty(param_name)) + return false; + len = strlen(param_name); + if (len < sfx_len) + return false; + param_name += len - sfx_len; + if (strncmp(param_name, "__sz", sfx_len)) + return false; + + return true; +} + +static bool is_kfunc_arg_scalar_with_name(const struct btf *btf, + const struct btf_param *arg, + const char *name) +{ + int len, target_len = strlen(name); + const char *param_name; + + param_name = btf_name_by_offset(btf, arg->name_off); + if (str_is_empty(param_name)) + return false; + len = strlen(param_name); + if (len != target_len) + return false; + if (strcmp(param_name, name)) + return false; + + return true; +} + +enum { + KF_ARG_DYNPTR_ID, +}; + +BTF_ID_LIST(kf_arg_btf_ids) +BTF_ID(struct, bpf_dynptr_kern) + +static bool is_kfunc_arg_dynptr(const struct btf *btf, + const struct btf_param *arg) +{ + const struct btf_type *t; + u32 res_id; + + t = btf_type_skip_modifiers(btf, arg->type, NULL); + if (!t) + return false; + if (!btf_type_is_ptr(t)) + return false; + t = btf_type_skip_modifiers(btf, t->type, &res_id); + if (!t) + return false; + return btf_types_are_same(btf, res_id, btf_vmlinux, kf_arg_btf_ids[KF_ARG_DYNPTR_ID]); +} + +/* Returns true if struct is composed of scalars, 4 levels of nesting allowed */ +static bool __btf_type_is_scalar_struct(struct bpf_verifier_env *env, + const struct btf *btf, + const struct btf_type *t, int rec) +{ + const struct btf_type *member_type; + const struct btf_member *member; + u32 i; + + if (!btf_type_is_struct(t)) + return false; + + for_each_member(i, t, member) { + const struct btf_array *array; + + member_type = btf_type_skip_modifiers(btf, member->type, NULL); + if (btf_type_is_struct(member_type)) { + if (rec >= 3) { + verbose(env, "max struct nesting depth exceeded\n"); + return false; + } + if (!__btf_type_is_scalar_struct(env, btf, member_type, rec + 1)) + return false; + continue; + } + if (btf_type_is_array(member_type)) { + array = btf_array(member_type); + if (!array->nelems) + return false; + member_type = btf_type_skip_modifiers(btf, array->type, NULL); + if (!btf_type_is_scalar(member_type)) + return false; + continue; + } + if (!btf_type_is_scalar(member_type)) + return false; + } + return true; +} + + +static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = { +#ifdef CONFIG_NET + [PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK], + [PTR_TO_SOCK_COMMON] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON], + [PTR_TO_TCP_SOCK] = &btf_sock_ids[BTF_SOCK_TYPE_TCP], +#endif +}; + +enum kfunc_ptr_arg_type { + KF_ARG_PTR_TO_CTX, + KF_ARG_PTR_TO_KPTR, /* PTR_TO_KPTR but type specific */ + KF_ARG_PTR_TO_DYNPTR, + KF_ARG_PTR_TO_BTF_ID, /* Also covers reg2btf_ids conversions */ + KF_ARG_PTR_TO_MEM, + KF_ARG_PTR_TO_MEM_SIZE, /* Size derived from next argument, skip it */ +}; + +static enum kfunc_ptr_arg_type +get_kfunc_ptr_arg_type(struct bpf_verifier_env *env, + struct bpf_kfunc_call_arg_meta *meta, + const struct btf_type *t, const struct btf_type *ref_t, + const char *ref_tname, const struct btf_param *args, + int argno, int nargs) +{ + u32 regno = argno + 1; + struct bpf_reg_state *regs = cur_regs(env); + struct bpf_reg_state *reg = ®s[regno]; + bool arg_mem_size = false; + + /* In this function, we verify the kfunc's BTF as per the argument type, + * leaving the rest of the verification with respect to the register + * type to our caller. When a set of conditions hold in the BTF type of + * arguments, we resolve it to a known kfunc_ptr_arg_type. + */ + if (btf_get_prog_ctx_type(&env->log, meta->btf, t, resolve_prog_type(env->prog), argno)) + return KF_ARG_PTR_TO_CTX; + + if (is_kfunc_arg_kptr_get(meta, argno)) { + if (!btf_type_is_ptr(ref_t)) { + verbose(env, "arg#0 BTF type must be a double pointer for kptr_get kfunc\n"); + return -EINVAL; + } + ref_t = btf_type_by_id(meta->btf, ref_t->type); + ref_tname = btf_name_by_offset(meta->btf, ref_t->name_off); + if (!btf_type_is_struct(ref_t)) { + verbose(env, "kernel function %s args#0 pointer type %s %s is not supported\n", + meta->func_name, btf_type_str(ref_t), ref_tname); + return -EINVAL; + } + return KF_ARG_PTR_TO_KPTR; + } + + if (is_kfunc_arg_dynptr(meta->btf, &args[argno])) + return KF_ARG_PTR_TO_DYNPTR; + + if ((base_type(reg->type) == PTR_TO_BTF_ID || reg2btf_ids[base_type(reg->type)])) { + if (!btf_type_is_struct(ref_t)) { + verbose(env, "kernel function %s args#%d pointer type %s %s is not supported\n", + meta->func_name, argno, btf_type_str(ref_t), ref_tname); + return -EINVAL; + } + return KF_ARG_PTR_TO_BTF_ID; + } + + if (argno + 1 < nargs && is_kfunc_arg_mem_size(meta->btf, &args[argno + 1], ®s[regno + 1])) + arg_mem_size = true; + + /* This is the catch all argument type of register types supported by + * check_helper_mem_access. However, we only allow when argument type is + * pointer to scalar, or struct composed (recursively) of scalars. When + * arg_mem_size is true, the pointer can be void *. + */ + if (!btf_type_is_scalar(ref_t) && !__btf_type_is_scalar_struct(env, meta->btf, ref_t, 0) && + (arg_mem_size ? !btf_type_is_void(ref_t) : 1)) { + verbose(env, "arg#%d pointer type %s %s must point to %sscalar, or struct with scalar\n", + argno, btf_type_str(ref_t), ref_tname, arg_mem_size ? "void, " : ""); + return -EINVAL; + } + return arg_mem_size ? KF_ARG_PTR_TO_MEM_SIZE : KF_ARG_PTR_TO_MEM; +} + +static int process_kf_arg_ptr_to_btf_id(struct bpf_verifier_env *env, + struct bpf_reg_state *reg, + const struct btf_type *ref_t, + const char *ref_tname, u32 ref_id, + struct bpf_kfunc_call_arg_meta *meta, + int argno) +{ + const struct btf_type *reg_ref_t; + bool strict_type_match = false; + const struct btf *reg_btf; + const char *reg_ref_tname; + u32 reg_ref_id; + + if (reg->type == PTR_TO_BTF_ID) { + reg_btf = reg->btf; + reg_ref_id = reg->btf_id; + } else { + reg_btf = btf_vmlinux; + reg_ref_id = *reg2btf_ids[base_type(reg->type)]; + } + + if (is_kfunc_trusted_args(meta) || (is_kfunc_release(meta) && reg->ref_obj_id)) + strict_type_match = true; + + reg_ref_t = btf_type_skip_modifiers(reg_btf, reg_ref_id, ®_ref_id); + reg_ref_tname = btf_name_by_offset(reg_btf, reg_ref_t->name_off); + if (!btf_struct_ids_match(&env->log, reg_btf, reg_ref_id, reg->off, meta->btf, ref_id, strict_type_match)) { + verbose(env, "kernel function %s args#%d expected pointer to %s %s but R%d has a pointer to %s %s\n", + meta->func_name, argno, btf_type_str(ref_t), ref_tname, argno + 1, + btf_type_str(reg_ref_t), reg_ref_tname); + return -EINVAL; + } + return 0; +} + +static int process_kf_arg_ptr_to_kptr(struct bpf_verifier_env *env, + struct bpf_reg_state *reg, + const struct btf_type *ref_t, + const char *ref_tname, + struct bpf_kfunc_call_arg_meta *meta, + int argno) +{ + struct btf_field *kptr_field; + + /* check_func_arg_reg_off allows var_off for + * PTR_TO_MAP_VALUE, but we need fixed offset to find + * off_desc. + */ + if (!tnum_is_const(reg->var_off)) { + verbose(env, "arg#0 must have constant offset\n"); + return -EINVAL; + } + + kptr_field = btf_record_find(reg->map_ptr->record, reg->off + reg->var_off.value, BPF_KPTR); + if (!kptr_field || kptr_field->type != BPF_KPTR_REF) { + verbose(env, "arg#0 no referenced kptr at map value offset=%llu\n", + reg->off + reg->var_off.value); + return -EINVAL; + } + + if (!btf_struct_ids_match(&env->log, meta->btf, ref_t->type, 0, kptr_field->kptr.btf, + kptr_field->kptr.btf_id, true)) { + verbose(env, "kernel function %s args#%d expected pointer to %s %s\n", + meta->func_name, argno, btf_type_str(ref_t), ref_tname); + return -EINVAL; + } + return 0; +} + +static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_arg_meta *meta) +{ + const char *func_name = meta->func_name, *ref_tname; + const struct btf *btf = meta->btf; + const struct btf_param *args; + u32 i, nargs; + int ret; + + args = (const struct btf_param *)(meta->func_proto + 1); + nargs = btf_type_vlen(meta->func_proto); + if (nargs > MAX_BPF_FUNC_REG_ARGS) { + verbose(env, "Function %s has %d > %d args\n", func_name, nargs, + MAX_BPF_FUNC_REG_ARGS); + return -EINVAL; + } + + /* Check that BTF function arguments match actual types that the + * verifier sees. + */ + for (i = 0; i < nargs; i++) { + struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[i + 1]; + const struct btf_type *t, *ref_t, *resolve_ret; + enum bpf_arg_type arg_type = ARG_DONTCARE; + u32 regno = i + 1, ref_id, type_size; + bool is_ret_buf_sz = false; + int kf_arg_type; + + t = btf_type_skip_modifiers(btf, args[i].type, NULL); + if (btf_type_is_scalar(t)) { + if (reg->type != SCALAR_VALUE) { + verbose(env, "R%d is not a scalar\n", regno); + return -EINVAL; + } + if (is_kfunc_arg_scalar_with_name(btf, &args[i], "rdonly_buf_size")) { + meta->r0_rdonly = true; + is_ret_buf_sz = true; + } else if (is_kfunc_arg_scalar_with_name(btf, &args[i], "rdwr_buf_size")) { + is_ret_buf_sz = true; + } + + if (is_ret_buf_sz) { + if (meta->r0_size) { + verbose(env, "2 or more rdonly/rdwr_buf_size parameters for kfunc"); + return -EINVAL; + } + + if (!tnum_is_const(reg->var_off)) { + verbose(env, "R%d is not a const\n", regno); + return -EINVAL; + } + + meta->r0_size = reg->var_off.value; + ret = mark_chain_precision(env, regno); + if (ret) + return ret; + } + continue; + } + + if (!btf_type_is_ptr(t)) { + verbose(env, "Unrecognized arg#%d type %s\n", i, btf_type_str(t)); + return -EINVAL; + } + + if (reg->ref_obj_id) { + if (is_kfunc_release(meta) && meta->ref_obj_id) { + verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n", + regno, reg->ref_obj_id, + meta->ref_obj_id); + return -EFAULT; + } + meta->ref_obj_id = reg->ref_obj_id; + if (is_kfunc_release(meta)) + meta->release_regno = regno; + } + + ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id); + ref_tname = btf_name_by_offset(btf, ref_t->name_off); + + kf_arg_type = get_kfunc_ptr_arg_type(env, meta, t, ref_t, ref_tname, args, i, nargs); + if (kf_arg_type < 0) + return kf_arg_type; + + switch (kf_arg_type) { + case KF_ARG_PTR_TO_BTF_ID: + if (!is_kfunc_trusted_args(meta)) + break; + if (!reg->ref_obj_id) { + verbose(env, "R%d must be referenced\n", regno); + return -EINVAL; + } + fallthrough; + case KF_ARG_PTR_TO_CTX: + /* Trusted arguments have the same offset checks as release arguments */ + arg_type |= OBJ_RELEASE; + break; + case KF_ARG_PTR_TO_KPTR: + case KF_ARG_PTR_TO_DYNPTR: + case KF_ARG_PTR_TO_MEM: + case KF_ARG_PTR_TO_MEM_SIZE: + /* Trusted by default */ + break; + default: + WARN_ON_ONCE(1); + return -EFAULT; + } + + if (is_kfunc_release(meta) && reg->ref_obj_id) + arg_type |= OBJ_RELEASE; + ret = check_func_arg_reg_off(env, reg, regno, arg_type); + if (ret < 0) + return ret; + + switch (kf_arg_type) { + case KF_ARG_PTR_TO_CTX: + if (reg->type != PTR_TO_CTX) { + verbose(env, "arg#%d expected pointer to ctx, but got %s\n", i, btf_type_str(t)); + return -EINVAL; + } + break; + case KF_ARG_PTR_TO_KPTR: + if (reg->type != PTR_TO_MAP_VALUE) { + verbose(env, "arg#0 expected pointer to map value\n"); + return -EINVAL; + } + ret = process_kf_arg_ptr_to_kptr(env, reg, ref_t, ref_tname, meta, i); + if (ret < 0) + return ret; + break; + case KF_ARG_PTR_TO_DYNPTR: + if (reg->type != PTR_TO_STACK) { + verbose(env, "arg#%d expected pointer to stack\n", i); + return -EINVAL; + } + + if (!is_dynptr_reg_valid_init(env, reg)) { + verbose(env, "arg#%d pointer type %s %s must be valid and initialized\n", + i, btf_type_str(ref_t), ref_tname); + return -EINVAL; + } + + if (!is_dynptr_type_expected(env, reg, ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_LOCAL)) { + verbose(env, "arg#%d pointer type %s %s points to unsupported dynamic pointer type\n", + i, btf_type_str(ref_t), ref_tname); + return -EINVAL; + } + break; + case KF_ARG_PTR_TO_BTF_ID: + /* Only base_type is checked, further checks are done here */ + if (reg->type != PTR_TO_BTF_ID && + (!reg2btf_ids[base_type(reg->type)] || type_flag(reg->type))) { + verbose(env, "arg#%d expected pointer to btf or socket\n", i); + return -EINVAL; + } + ret = process_kf_arg_ptr_to_btf_id(env, reg, ref_t, ref_tname, ref_id, meta, i); + if (ret < 0) + return ret; + break; + case KF_ARG_PTR_TO_MEM: + resolve_ret = btf_resolve_size(btf, ref_t, &type_size); + if (IS_ERR(resolve_ret)) { + verbose(env, "arg#%d reference type('%s %s') size cannot be determined: %ld\n", + i, btf_type_str(ref_t), ref_tname, PTR_ERR(resolve_ret)); + return -EINVAL; + } + ret = check_mem_reg(env, reg, regno, type_size); + if (ret < 0) + return ret; + break; + case KF_ARG_PTR_TO_MEM_SIZE: + ret = check_kfunc_mem_size_reg(env, ®s[regno + 1], regno + 1); + if (ret < 0) { + verbose(env, "arg#%d arg#%d memory, len pair leads to invalid memory access\n", i, i + 1); + return ret; + } + /* Skip next '__sz' argument */ + i++; + break; + } + } + + if (is_kfunc_release(meta) && !meta->release_regno) { + verbose(env, "release kernel function %s expects refcounted PTR_TO_BTF_ID\n", + func_name); + return -EINVAL; + } + + return 0; +} + static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, int *insn_idx_p) { const struct btf_type *t, *func, *func_proto, *ptr_type; struct bpf_reg_state *regs = cur_regs(env); - struct bpf_kfunc_arg_meta meta = { 0 }; const char *func_name, *ptr_type_name; + struct bpf_kfunc_call_arg_meta meta; u32 i, nargs, func_id, ptr_type_id; int err, insn_idx = *insn_idx_p; const struct btf_param *args; struct btf *desc_btf; u32 *kfunc_flags; - bool acq; /* skip for now, but return error when we find this in fixup_kfunc_call */ if (!insn->imm) @@ -7896,24 +8394,34 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, func_name); return -EACCES; } - if (*kfunc_flags & KF_DESTRUCTIVE && !capable(CAP_SYS_BOOT)) { - verbose(env, "destructive kfunc calls require CAP_SYS_BOOT capabilities\n"); + + /* Prepare kfunc call metadata */ + memset(&meta, 0, sizeof(meta)); + meta.btf = desc_btf; + meta.func_id = func_id; + meta.kfunc_flags = *kfunc_flags; + meta.func_proto = func_proto; + meta.func_name = func_name; + + if (is_kfunc_destructive(&meta) && !capable(CAP_SYS_BOOT)) { + verbose(env, "destructive kfunc calls require CAP_SYS_BOOT capability\n"); return -EACCES; } - acq = *kfunc_flags & KF_ACQUIRE; - - meta.flags = *kfunc_flags; + if (is_kfunc_sleepable(&meta) && !env->prog->aux->sleepable) { + verbose(env, "program must be sleepable to call sleepable kfunc %s\n", func_name); + return -EACCES; + } /* Check the arguments */ - err = btf_check_kfunc_arg_match(env, desc_btf, func_id, regs, &meta); + err = check_kfunc_args(env, &meta); if (err < 0) return err; /* In case of release function, we get register number of refcounted - * PTR_TO_BTF_ID back from btf_check_kfunc_arg_match, do the release now + * PTR_TO_BTF_ID in bpf_kfunc_arg_meta, do the release now. */ - if (err) { - err = release_reference(env, regs[err].ref_obj_id); + if (meta.release_regno) { + err = release_reference(env, regs[meta.release_regno].ref_obj_id); if (err) { verbose(env, "kfunc %s#%d reference has not been acquired before\n", func_name, func_id); @@ -7927,7 +8435,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, /* Check return type */ t = btf_type_skip_modifiers(desc_btf, func_proto->type, NULL); - if (acq && !btf_type_is_struct_ptr(desc_btf, t)) { + if (is_kfunc_acquire(&meta) && !btf_type_is_struct_ptr(meta.btf, t)) { verbose(env, "acquire kernel function does not return PTR_TO_BTF_ID\n"); return -EINVAL; } @@ -7966,20 +8474,23 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, regs[BPF_REG_0].type = PTR_TO_BTF_ID; regs[BPF_REG_0].btf_id = ptr_type_id; } - if (*kfunc_flags & KF_RET_NULL) { + if (is_kfunc_ret_null(&meta)) { regs[BPF_REG_0].type |= PTR_MAYBE_NULL; /* For mark_ptr_or_null_reg, see 93c230e3f5bd6 */ regs[BPF_REG_0].id = ++env->id_gen; } mark_btf_func_reg_size(env, BPF_REG_0, sizeof(void *)); - if (acq) { + if (is_kfunc_acquire(&meta)) { int id = acquire_reference_state(env, insn_idx); if (id < 0) return id; - regs[BPF_REG_0].id = id; + if (is_kfunc_ret_null(&meta)) + regs[BPF_REG_0].id = id; regs[BPF_REG_0].ref_obj_id = id; } + if (reg_may_point_to_spin_lock(®s[BPF_REG_0]) && !regs[BPF_REG_0].id) + regs[BPF_REG_0].id = ++env->id_gen; } /* else { add_kfunc_call() ensures it is btf_type_is_void(t) } */ nargs = btf_type_vlen(func_proto); diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c b/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c index c210657d4d0a..55d641c1f126 100644 --- a/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c +++ b/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c @@ -22,7 +22,7 @@ static struct { "arg#0 pointer type STRUCT bpf_dynptr_kern points to unsupported dynamic pointer type", 0}, {"not_valid_dynptr", "arg#0 pointer type STRUCT bpf_dynptr_kern must be valid and initialized", 0}, - {"not_ptr_to_stack", "arg#0 pointer type STRUCT bpf_dynptr_kern not to stack", 0}, + {"not_ptr_to_stack", "arg#0 expected pointer to stack", 0}, {"dynptr_data_null", NULL, -EBADMSG}, }; diff --git a/tools/testing/selftests/bpf/verifier/calls.c b/tools/testing/selftests/bpf/verifier/calls.c index e1a937277b54..86d6fef2e3b4 100644 --- a/tools/testing/selftests/bpf/verifier/calls.c +++ b/tools/testing/selftests/bpf/verifier/calls.c @@ -109,7 +109,7 @@ }, .prog_type = BPF_PROG_TYPE_SCHED_CLS, .result = REJECT, - .errstr = "arg#0 pointer type STRUCT prog_test_ref_kfunc must point", + .errstr = "arg#0 expected pointer to btf or socket", .fixup_kfunc_btf_id = { { "bpf_kfunc_call_test_acquire", 3 }, { "bpf_kfunc_call_test_release", 5 }, diff --git a/tools/testing/selftests/bpf/verifier/ref_tracking.c b/tools/testing/selftests/bpf/verifier/ref_tracking.c index fd683a32a276..55cba01c99d5 100644 --- a/tools/testing/selftests/bpf/verifier/ref_tracking.c +++ b/tools/testing/selftests/bpf/verifier/ref_tracking.c @@ -142,7 +142,7 @@ .kfunc = "bpf", .expected_attach_type = BPF_LSM_MAC, .flags = BPF_F_SLEEPABLE, - .errstr = "arg#0 pointer type STRUCT bpf_key must point to scalar, or struct with scalar", + .errstr = "arg#0 expected pointer to btf or socket", .fixup_kfunc_btf_id = { { "bpf_lookup_user_key", 2 }, { "bpf_key_put", 4 }, @@ -163,7 +163,7 @@ .kfunc = "bpf", .expected_attach_type = BPF_LSM_MAC, .flags = BPF_F_SLEEPABLE, - .errstr = "arg#0 pointer type STRUCT bpf_key must point to scalar, or struct with scalar", + .errstr = "arg#0 expected pointer to btf or socket", .fixup_kfunc_btf_id = { { "bpf_lookup_system_key", 1 }, { "bpf_key_put", 3 }, From a50388dbb328a4267c2b91ad4aefe81b08e49b2d Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:26:02 +0530 Subject: [PATCH 037/101] bpf: Support constant scalar arguments for kfuncs Allow passing known constant scalars as arguments to kfuncs that do not represent a size parameter. We use mark_chain_precision for the constant scalar argument to mark it precise. This makes the search pruning optimization of verifier more conservative for such kfunc calls, and each non-distinct argument is considered unequivalent. We will use this support to then expose a bpf_obj_new function where it takes the local type ID of a type in program BTF, and returns a PTR_TO_BTF_ID | MEM_ALLOC to the local type, and allows programs to allocate their own objects. Each type ID resolves to a distinct type with a possibly distinct size, hence the type ID constant matters in terms of program safety and its precision needs to be checked between old and cur states inside regsafe. The use of mark_chain_precision enables this. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-13-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- Documentation/bpf/kfuncs.rst | 24 +++++++++++++++ kernel/bpf/verifier.c | 57 +++++++++++++++++++++++++++--------- 2 files changed, 67 insertions(+), 14 deletions(-) diff --git a/Documentation/bpf/kfuncs.rst b/Documentation/bpf/kfuncs.rst index 0f858156371d..3b1501c3b6cd 100644 --- a/Documentation/bpf/kfuncs.rst +++ b/Documentation/bpf/kfuncs.rst @@ -72,6 +72,30 @@ argument as its size. By default, without __sz annotation, the size of the type of the pointer is used. Without __sz annotation, a kfunc cannot accept a void pointer. +2.2.2 __k Annotation +-------------------- + +This annotation is only understood for scalar arguments, where it indicates that +the verifier must check the scalar argument to be a known constant, which does +not indicate a size parameter, and the value of the constant is relevant to the +safety of the program. + +An example is given below:: + + void *bpf_obj_new(u32 local_type_id__k, ...) + { + ... + } + +Here, bpf_obj_new uses local_type_id argument to find out the size of that type +ID in program's BTF and return a sized pointer to it. Each type ID will have a +distinct size, hence it is crucial to treat each such call as distinct when +values don't match during verifier state pruning checks. + +Hence, whenever a constant scalar argument is accepted by a kfunc which is not a +size parameter, and the value of the constant matters for program safety, __k +suffix should be used. + .. _BPF_kfunc_nodef: 2.3 Using an existing kernel function diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 7d7a91c54709..c8fcc2808d99 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -7875,6 +7875,10 @@ struct bpf_kfunc_call_arg_meta { u8 release_regno; bool r0_rdonly; u64 r0_size; + struct { + u64 value; + bool found; + } arg_constant; }; static bool is_kfunc_acquire(struct bpf_kfunc_call_arg_meta *meta) @@ -7912,30 +7916,40 @@ static bool is_kfunc_arg_kptr_get(struct bpf_kfunc_call_arg_meta *meta, int arg) return arg == 0 && (meta->kfunc_flags & KF_KPTR_GET); } -static bool is_kfunc_arg_mem_size(const struct btf *btf, - const struct btf_param *arg, - const struct bpf_reg_state *reg) +static bool __kfunc_param_match_suffix(const struct btf *btf, + const struct btf_param *arg, + const char *suffix) { - int len, sfx_len = sizeof("__sz") - 1; - const struct btf_type *t; + int suffix_len = strlen(suffix), len; const char *param_name; - t = btf_type_skip_modifiers(btf, arg->type, NULL); - if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE) - return false; - /* In the future, this can be ported to use BTF tagging */ param_name = btf_name_by_offset(btf, arg->name_off); if (str_is_empty(param_name)) return false; len = strlen(param_name); - if (len < sfx_len) + if (len < suffix_len) return false; - param_name += len - sfx_len; - if (strncmp(param_name, "__sz", sfx_len)) + param_name += len - suffix_len; + return !strncmp(param_name, suffix, suffix_len); +} + +static bool is_kfunc_arg_mem_size(const struct btf *btf, + const struct btf_param *arg, + const struct bpf_reg_state *reg) +{ + const struct btf_type *t; + + t = btf_type_skip_modifiers(btf, arg->type, NULL); + if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE) return false; - return true; + return __kfunc_param_match_suffix(btf, arg, "__sz"); +} + +static bool is_kfunc_arg_constant(const struct btf *btf, const struct btf_param *arg) +{ + return __kfunc_param_match_suffix(btf, arg, "__k"); } static bool is_kfunc_arg_scalar_with_name(const struct btf *btf, @@ -8205,7 +8219,22 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ verbose(env, "R%d is not a scalar\n", regno); return -EINVAL; } - if (is_kfunc_arg_scalar_with_name(btf, &args[i], "rdonly_buf_size")) { + + if (is_kfunc_arg_constant(meta->btf, &args[i])) { + if (meta->arg_constant.found) { + verbose(env, "verifier internal error: only one constant argument permitted\n"); + return -EFAULT; + } + if (!tnum_is_const(reg->var_off)) { + verbose(env, "R%d must be a known constant\n", regno); + return -EINVAL; + } + ret = mark_chain_precision(env, regno); + if (ret < 0) + return ret; + meta->arg_constant.found = true; + meta->arg_constant.value = reg->var_off.value; + } else if (is_kfunc_arg_scalar_with_name(btf, &args[i], "rdonly_buf_size")) { meta->r0_rdonly = true; is_ret_buf_sz = true; } else if (is_kfunc_arg_scalar_with_name(btf, &args[i], "rdwr_buf_size")) { From 958cf2e273f0929c66169e0788031310e8118722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:26:03 +0530 Subject: [PATCH 038/101] bpf: Introduce bpf_obj_new Introduce type safe memory allocator bpf_obj_new for BPF programs. The kernel side kfunc is named bpf_obj_new_impl, as passing hidden arguments to kfuncs still requires having them in prototype, unlike BPF helpers which always take 5 arguments and have them checked using bpf_func_proto in verifier, ignoring unset argument types. Introduce __ign suffix to ignore a specific kfunc argument during type checks, then use this to introduce support for passing type metadata to the bpf_obj_new_impl kfunc. The user passes BTF ID of the type it wants to allocates in program BTF, the verifier then rewrites the first argument as the size of this type, after performing some sanity checks (to ensure it exists and it is a struct type). The second argument is also fixed up and passed by the verifier. This is the btf_struct_meta for the type being allocated. It would be needed mostly for the offset array which is required for zero initializing special fields while leaving the rest of storage in unitialized state. It would also be needed in the next patch to perform proper destruction of the object's special fields. Under the hood, bpf_obj_new will call bpf_mem_alloc and bpf_mem_free, using the any context BPF memory allocator introduced recently. To this end, a global instance of the BPF memory allocator is initialized on boot to be used for this purpose. This 'bpf_global_ma' serves all allocations for bpf_obj_new. In the future, bpf_obj_new variants will allow specifying a custom allocator. Note that now that bpf_obj_new can be used to allocate objects that can be linked to BPF linked list (when future linked list helpers are available), we need to also free the elements using bpf_mem_free. However, since the draining of elements is done outside the bpf_spin_lock, we need to do migrate_disable around the call since bpf_list_head_free can be called from map free path where migration is enabled. Otherwise, when called from BPF programs migration is already disabled. A convenience macro is included in the bpf_experimental.h header to hide over the ugly details of the implementation, leading to user code looking similar to a language level extension which allocates and constructs fields of a user type. struct bar { struct bpf_list_node node; }; struct foo { struct bpf_spin_lock lock; struct bpf_list_head head __contains(bar, node); }; void prog(void) { struct foo *f; f = bpf_obj_new(typeof(*f)); if (!f) return; ... } A key piece of this story is still missing, i.e. the free function, which will come in the next patch. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-14-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/linux/bpf.h | 21 ++-- include/linux/bpf_verifier.h | 2 + kernel/bpf/core.c | 16 +++ kernel/bpf/helpers.c | 47 ++++++-- kernel/bpf/verifier.c | 102 ++++++++++++++++-- .../testing/selftests/bpf/bpf_experimental.h | 25 +++++ 6 files changed, 190 insertions(+), 23 deletions(-) create mode 100644 tools/testing/selftests/bpf/bpf_experimental.h diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 0a74df731eb8..8b32376ce746 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -54,6 +54,8 @@ struct cgroup; extern struct idr btf_idr; extern spinlock_t btf_idr_lock; extern struct kobject *btf_kobj; +extern struct bpf_mem_alloc bpf_global_ma; +extern bool bpf_global_ma_set; typedef u64 (*bpf_callback_t)(u64, u64, u64, u64, u64); typedef int (*bpf_iter_init_seq_priv_t)(void *private_data, @@ -334,16 +336,19 @@ static inline bool btf_record_has_field(const struct btf_record *rec, enum btf_f return rec->field_mask & type; } +static inline void bpf_obj_init(const struct btf_field_offs *foffs, void *obj) +{ + int i; + + if (!foffs) + return; + for (i = 0; i < foffs->cnt; i++) + memset(obj + foffs->field_off[i], 0, foffs->field_sz[i]); +} + static inline void check_and_init_map_value(struct bpf_map *map, void *dst) { - if (!IS_ERR_OR_NULL(map->record)) { - struct btf_field *fields = map->record->fields; - u32 cnt = map->record->cnt; - int i; - - for (i = 0; i < cnt; i++) - memset(dst + fields[i].offset, 0, btf_field_type_size(fields[i].type)); - } + bpf_obj_init(map->field_offs, dst); } /* memcpy that is used with 8-byte aligned pointers, power-of-8 size and diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index fb146b0ce006..3dc72d396dfc 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -433,6 +433,8 @@ struct bpf_insn_aux_data { */ struct bpf_loop_inline_state loop_inline_state; }; + u64 obj_new_size; /* remember the size of type passed to bpf_obj_new to rewrite R1 */ + struct btf_struct_meta *kptr_struct_meta; u64 map_key_state; /* constant (32 bit) key tracking for maps */ int ctx_field_size; /* the ctx field size for load insn, maybe 0 */ u32 seen; /* this insn was processed by the verifier at env->pass_cnt */ diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 9c16338bcbe8..2e57fc839a5c 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -34,6 +34,7 @@ #include #include #include +#include #include #include @@ -60,6 +61,9 @@ #define CTX regs[BPF_REG_CTX] #define IMM insn->imm +struct bpf_mem_alloc bpf_global_ma; +bool bpf_global_ma_set; + /* No hurry in this branch * * Exported for the bpf jit load helper. @@ -2746,6 +2750,18 @@ int __weak bpf_arch_text_invalidate(void *dst, size_t len) return -ENOTSUPP; } +#ifdef CONFIG_BPF_SYSCALL +static int __init bpf_global_ma_init(void) +{ + int ret; + + ret = bpf_mem_alloc_init(&bpf_global_ma, 0, false); + bpf_global_ma_set = !ret; + return ret; +} +late_initcall(bpf_global_ma_init); +#endif + DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key); EXPORT_SYMBOL(bpf_stats_enabled_key); diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 5bc0b9f0f306..c4f1c22cc44c 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -19,6 +19,7 @@ #include #include #include +#include #include "../../lib/kstrtox.h" @@ -1735,25 +1736,57 @@ unlock: obj -= field->list_head.node_offset; head = head->next; - /* TODO: Rework later */ - kfree(obj); + /* The contained type can also have resources, including a + * bpf_list_head which needs to be freed. + */ + bpf_obj_free_fields(field->list_head.value_rec, obj); + /* bpf_mem_free requires migrate_disable(), since we can be + * called from map free path as well apart from BPF program (as + * part of map ops doing bpf_obj_free_fields). + */ + migrate_disable(); + bpf_mem_free(&bpf_global_ma, obj); + migrate_enable(); } } -BTF_SET8_START(tracing_btf_ids) +__diag_push(); +__diag_ignore_all("-Wmissing-prototypes", + "Global functions as their definitions will be in vmlinux BTF"); + +void *bpf_obj_new_impl(u64 local_type_id__k, void *meta__ign) +{ + struct btf_struct_meta *meta = meta__ign; + u64 size = local_type_id__k; + void *p; + + if (unlikely(!bpf_global_ma_set)) + return NULL; + p = bpf_mem_alloc(&bpf_global_ma, size); + if (!p) + return NULL; + if (meta) + bpf_obj_init(meta->field_offs, p); + return p; +} + +__diag_pop(); + +BTF_SET8_START(generic_btf_ids) #ifdef CONFIG_KEXEC_CORE BTF_ID_FLAGS(func, crash_kexec, KF_DESTRUCTIVE) #endif -BTF_SET8_END(tracing_btf_ids) +BTF_ID_FLAGS(func, bpf_obj_new_impl, KF_ACQUIRE | KF_RET_NULL) +BTF_SET8_END(generic_btf_ids) -static const struct btf_kfunc_id_set tracing_kfunc_set = { +static const struct btf_kfunc_id_set generic_kfunc_set = { .owner = THIS_MODULE, - .set = &tracing_btf_ids, + .set = &generic_btf_ids, }; static int __init kfunc_init(void) { - return register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &tracing_kfunc_set); + return register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &generic_kfunc_set); } late_initcall(kfunc_init); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index c8fcc2808d99..804f3bca6c08 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -7952,6 +7952,11 @@ static bool is_kfunc_arg_constant(const struct btf *btf, const struct btf_param return __kfunc_param_match_suffix(btf, arg, "__k"); } +static bool is_kfunc_arg_ignore(const struct btf *btf, const struct btf_param *arg) +{ + return __kfunc_param_match_suffix(btf, arg, "__ign"); +} + static bool is_kfunc_arg_scalar_with_name(const struct btf *btf, const struct btf_param *arg, const char *name) @@ -8214,6 +8219,10 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ int kf_arg_type; t = btf_type_skip_modifiers(btf, args[i].type, NULL); + + if (is_kfunc_arg_ignore(btf, &args[i])) + continue; + if (btf_type_is_scalar(t)) { if (reg->type != SCALAR_VALUE) { verbose(env, "R%d is not a scalar\n", regno); @@ -8391,6 +8400,17 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ return 0; } +enum special_kfunc_type { + KF_bpf_obj_new_impl, +}; + +BTF_SET_START(special_kfunc_set) +BTF_ID(func, bpf_obj_new_impl) +BTF_SET_END(special_kfunc_set) + +BTF_ID_LIST(special_kfunc_list) +BTF_ID(func, bpf_obj_new_impl) + static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, int *insn_idx_p) { @@ -8465,17 +8485,59 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, t = btf_type_skip_modifiers(desc_btf, func_proto->type, NULL); if (is_kfunc_acquire(&meta) && !btf_type_is_struct_ptr(meta.btf, t)) { - verbose(env, "acquire kernel function does not return PTR_TO_BTF_ID\n"); - return -EINVAL; + /* Only exception is bpf_obj_new_impl */ + if (meta.btf != btf_vmlinux || meta.func_id != special_kfunc_list[KF_bpf_obj_new_impl]) { + verbose(env, "acquire kernel function does not return PTR_TO_BTF_ID\n"); + return -EINVAL; + } } if (btf_type_is_scalar(t)) { mark_reg_unknown(env, regs, BPF_REG_0); mark_btf_func_reg_size(env, BPF_REG_0, t->size); } else if (btf_type_is_ptr(t)) { - ptr_type = btf_type_skip_modifiers(desc_btf, t->type, - &ptr_type_id); - if (!btf_type_is_struct(ptr_type)) { + ptr_type = btf_type_skip_modifiers(desc_btf, t->type, &ptr_type_id); + + if (meta.btf == btf_vmlinux && btf_id_set_contains(&special_kfunc_set, meta.func_id)) { + if (meta.func_id == special_kfunc_list[KF_bpf_obj_new_impl]) { + const struct btf_type *ret_t; + struct btf *ret_btf; + u32 ret_btf_id; + + if (((u64)(u32)meta.arg_constant.value) != meta.arg_constant.value) { + verbose(env, "local type ID argument must be in range [0, U32_MAX]\n"); + return -EINVAL; + } + + ret_btf = env->prog->aux->btf; + ret_btf_id = meta.arg_constant.value; + + /* This may be NULL due to user not supplying a BTF */ + if (!ret_btf) { + verbose(env, "bpf_obj_new requires prog BTF\n"); + return -EINVAL; + } + + ret_t = btf_type_by_id(ret_btf, ret_btf_id); + if (!ret_t || !__btf_type_is_struct(ret_t)) { + verbose(env, "bpf_obj_new type ID argument must be of a struct\n"); + return -EINVAL; + } + + mark_reg_known_zero(env, regs, BPF_REG_0); + regs[BPF_REG_0].type = PTR_TO_BTF_ID | MEM_ALLOC; + regs[BPF_REG_0].btf = ret_btf; + regs[BPF_REG_0].btf_id = ret_btf_id; + + env->insn_aux_data[insn_idx].obj_new_size = ret_t->size; + env->insn_aux_data[insn_idx].kptr_struct_meta = + btf_find_struct_meta(ret_btf, ret_btf_id); + } else { + verbose(env, "kernel function %s unhandled dynamic return type\n", + meta.func_name); + return -EFAULT; + } + } else if (!__btf_type_is_struct(ptr_type)) { if (!meta.r0_size) { ptr_type_name = btf_name_by_offset(desc_btf, ptr_type->name_off); @@ -8503,6 +8565,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, regs[BPF_REG_0].type = PTR_TO_BTF_ID; regs[BPF_REG_0].btf_id = ptr_type_id; } + if (is_kfunc_ret_null(&meta)) { regs[BPF_REG_0].type |= PTR_MAYBE_NULL; /* For mark_ptr_or_null_reg, see 93c230e3f5bd6 */ @@ -14671,8 +14734,8 @@ static int fixup_call_args(struct bpf_verifier_env *env) return err; } -static int fixup_kfunc_call(struct bpf_verifier_env *env, - struct bpf_insn *insn) +static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, + struct bpf_insn *insn_buf, int insn_idx, int *cnt) { const struct bpf_kfunc_desc *desc; @@ -14691,8 +14754,21 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, return -EFAULT; } + *cnt = 0; insn->imm = desc->imm; + if (insn->off) + return 0; + if (desc->func_id == special_kfunc_list[KF_bpf_obj_new_impl]) { + struct btf_struct_meta *kptr_struct_meta = env->insn_aux_data[insn_idx].kptr_struct_meta; + struct bpf_insn addr[2] = { BPF_LD_IMM64(BPF_REG_2, (long)kptr_struct_meta) }; + u64 obj_new_size = env->insn_aux_data[insn_idx].obj_new_size; + insn_buf[0] = BPF_MOV64_IMM(BPF_REG_1, obj_new_size); + insn_buf[1] = addr[0]; + insn_buf[2] = addr[1]; + insn_buf[3] = *insn; + *cnt = 4; + } return 0; } @@ -14834,9 +14910,19 @@ static int do_misc_fixups(struct bpf_verifier_env *env) if (insn->src_reg == BPF_PSEUDO_CALL) continue; if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) { - ret = fixup_kfunc_call(env, insn); + ret = fixup_kfunc_call(env, insn, insn_buf, i + delta, &cnt); if (ret) return ret; + if (cnt == 0) + continue; + + new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); + if (!new_prog) + return -ENOMEM; + + delta += cnt - 1; + env->prog = prog = new_prog; + insn = new_prog->insnsi + i + delta; continue; } diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h new file mode 100644 index 000000000000..aeb6a7fcb7c4 --- /dev/null +++ b/tools/testing/selftests/bpf/bpf_experimental.h @@ -0,0 +1,25 @@ +#ifndef __BPF_EXPERIMENTAL__ +#define __BPF_EXPERIMENTAL__ + +#include +#include +#include +#include + +/* Description + * Allocates an object of the type represented by 'local_type_id' in + * program BTF. User may use the bpf_core_type_id_local macro to pass the + * type ID of a struct in program BTF. + * + * The 'local_type_id' parameter must be a known constant. + * The 'meta' parameter is a hidden argument that is ignored. + * Returns + * A pointer to an object of the type corresponding to the passed in + * 'local_type_id', or NULL on failure. + */ +extern void *bpf_obj_new_impl(__u64 local_type_id, void *meta) __ksym; + +/* Convenience macro to wrap over bpf_obj_new_impl */ +#define bpf_obj_new(type) ((type *)bpf_obj_new_impl(bpf_core_type_id_local(type), NULL)) + +#endif From ac9f06050a3580cf4076a57a470cd71f12a81171 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:26:04 +0530 Subject: [PATCH 039/101] bpf: Introduce bpf_obj_drop Introduce bpf_obj_drop, which is the kfunc used to free allocated objects (allocated using bpf_obj_new). Pairing with bpf_obj_new, it implicitly destructs the fields part of object automatically without user intervention. Just like the previous patch, btf_struct_meta that is needed to free up the special fields is passed as a hidden argument to the kfunc. For the user, a convenience macro hides over the kernel side kfunc which is named bpf_obj_drop_impl. Continuing the previous example: void prog(void) { struct foo *f; f = bpf_obj_new(typeof(*f)); if (!f) return; bpf_obj_drop(f); } Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-15-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/helpers.c | 11 ++++ kernel/bpf/verifier.c | 66 +++++++++++++++---- .../testing/selftests/bpf/bpf_experimental.h | 13 ++++ 3 files changed, 79 insertions(+), 11 deletions(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index c4f1c22cc44c..71d803ca0c1d 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1770,6 +1770,16 @@ void *bpf_obj_new_impl(u64 local_type_id__k, void *meta__ign) return p; } +void bpf_obj_drop_impl(void *p__alloc, void *meta__ign) +{ + struct btf_struct_meta *meta = meta__ign; + void *p = p__alloc; + + if (meta) + bpf_obj_free_fields(meta->record, p); + bpf_mem_free(&bpf_global_ma, p); +} + __diag_pop(); BTF_SET8_START(generic_btf_ids) @@ -1777,6 +1787,7 @@ BTF_SET8_START(generic_btf_ids) BTF_ID_FLAGS(func, crash_kexec, KF_DESTRUCTIVE) #endif BTF_ID_FLAGS(func, bpf_obj_new_impl, KF_ACQUIRE | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_obj_drop_impl, KF_RELEASE) BTF_SET8_END(generic_btf_ids) static const struct btf_kfunc_id_set generic_kfunc_set = { diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 804f3bca6c08..1fbb0b51c429 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -7879,6 +7879,10 @@ struct bpf_kfunc_call_arg_meta { u64 value; bool found; } arg_constant; + struct { + struct btf *btf; + u32 btf_id; + } arg_obj_drop; }; static bool is_kfunc_acquire(struct bpf_kfunc_call_arg_meta *meta) @@ -7957,6 +7961,11 @@ static bool is_kfunc_arg_ignore(const struct btf *btf, const struct btf_param *a return __kfunc_param_match_suffix(btf, arg, "__ign"); } +static bool is_kfunc_arg_alloc_obj(const struct btf *btf, const struct btf_param *arg) +{ + return __kfunc_param_match_suffix(btf, arg, "__alloc"); +} + static bool is_kfunc_arg_scalar_with_name(const struct btf *btf, const struct btf_param *arg, const char *name) @@ -8051,6 +8060,7 @@ static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = { enum kfunc_ptr_arg_type { KF_ARG_PTR_TO_CTX, + KF_ARG_PTR_TO_ALLOC_BTF_ID, /* Allocated object */ KF_ARG_PTR_TO_KPTR, /* PTR_TO_KPTR but type specific */ KF_ARG_PTR_TO_DYNPTR, KF_ARG_PTR_TO_BTF_ID, /* Also covers reg2btf_ids conversions */ @@ -8058,6 +8068,20 @@ enum kfunc_ptr_arg_type { KF_ARG_PTR_TO_MEM_SIZE, /* Size derived from next argument, skip it */ }; +enum special_kfunc_type { + KF_bpf_obj_new_impl, + KF_bpf_obj_drop_impl, +}; + +BTF_SET_START(special_kfunc_set) +BTF_ID(func, bpf_obj_new_impl) +BTF_ID(func, bpf_obj_drop_impl) +BTF_SET_END(special_kfunc_set) + +BTF_ID_LIST(special_kfunc_list) +BTF_ID(func, bpf_obj_new_impl) +BTF_ID(func, bpf_obj_drop_impl) + static enum kfunc_ptr_arg_type get_kfunc_ptr_arg_type(struct bpf_verifier_env *env, struct bpf_kfunc_call_arg_meta *meta, @@ -8078,6 +8102,9 @@ get_kfunc_ptr_arg_type(struct bpf_verifier_env *env, if (btf_get_prog_ctx_type(&env->log, meta->btf, t, resolve_prog_type(env->prog), argno)) return KF_ARG_PTR_TO_CTX; + if (is_kfunc_arg_alloc_obj(meta->btf, &args[argno])) + return KF_ARG_PTR_TO_ALLOC_BTF_ID; + if (is_kfunc_arg_kptr_get(meta, argno)) { if (!btf_type_is_ptr(ref_t)) { verbose(env, "arg#0 BTF type must be a double pointer for kptr_get kfunc\n"); @@ -8294,6 +8321,7 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ return kf_arg_type; switch (kf_arg_type) { + case KF_ARG_PTR_TO_ALLOC_BTF_ID: case KF_ARG_PTR_TO_BTF_ID: if (!is_kfunc_trusted_args(meta)) break; @@ -8330,6 +8358,21 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ return -EINVAL; } break; + case KF_ARG_PTR_TO_ALLOC_BTF_ID: + if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) { + verbose(env, "arg#%d expected pointer to allocated object\n", i); + return -EINVAL; + } + if (!reg->ref_obj_id) { + verbose(env, "allocated object must be referenced\n"); + return -EINVAL; + } + if (meta->btf == btf_vmlinux && + meta->func_id == special_kfunc_list[KF_bpf_obj_drop_impl]) { + meta->arg_obj_drop.btf = reg->btf; + meta->arg_obj_drop.btf_id = reg->btf_id; + } + break; case KF_ARG_PTR_TO_KPTR: if (reg->type != PTR_TO_MAP_VALUE) { verbose(env, "arg#0 expected pointer to map value\n"); @@ -8400,17 +8443,6 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ return 0; } -enum special_kfunc_type { - KF_bpf_obj_new_impl, -}; - -BTF_SET_START(special_kfunc_set) -BTF_ID(func, bpf_obj_new_impl) -BTF_SET_END(special_kfunc_set) - -BTF_ID_LIST(special_kfunc_list) -BTF_ID(func, bpf_obj_new_impl) - static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, int *insn_idx_p) { @@ -8532,6 +8564,10 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, env->insn_aux_data[insn_idx].obj_new_size = ret_t->size; env->insn_aux_data[insn_idx].kptr_struct_meta = btf_find_struct_meta(ret_btf, ret_btf_id); + } else if (meta.func_id == special_kfunc_list[KF_bpf_obj_drop_impl]) { + env->insn_aux_data[insn_idx].kptr_struct_meta = + btf_find_struct_meta(meta.arg_obj_drop.btf, + meta.arg_obj_drop.btf_id); } else { verbose(env, "kernel function %s unhandled dynamic return type\n", meta.func_name); @@ -14768,6 +14804,14 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, insn_buf[2] = addr[1]; insn_buf[3] = *insn; *cnt = 4; + } else if (desc->func_id == special_kfunc_list[KF_bpf_obj_drop_impl]) { + struct btf_struct_meta *kptr_struct_meta = env->insn_aux_data[insn_idx].kptr_struct_meta; + struct bpf_insn addr[2] = { BPF_LD_IMM64(BPF_REG_2, (long)kptr_struct_meta) }; + + insn_buf[0] = addr[0]; + insn_buf[1] = addr[1]; + insn_buf[2] = *insn; + *cnt = 3; } return 0; } diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h index aeb6a7fcb7c4..8473395a11af 100644 --- a/tools/testing/selftests/bpf/bpf_experimental.h +++ b/tools/testing/selftests/bpf/bpf_experimental.h @@ -22,4 +22,17 @@ extern void *bpf_obj_new_impl(__u64 local_type_id, void *meta) __ksym; /* Convenience macro to wrap over bpf_obj_new_impl */ #define bpf_obj_new(type) ((type *)bpf_obj_new_impl(bpf_core_type_id_local(type), NULL)) +/* Description + * Free an allocated object. All fields of the object that require + * destruction will be destructed before the storage is freed. + * + * The 'meta' parameter is a hidden argument that is ignored. + * Returns + * Void. + */ +extern void bpf_obj_drop_impl(void *kptr, void *meta) __ksym; + +/* Convenience macro to wrap over bpf_obj_drop_impl */ +#define bpf_obj_drop(kptr) bpf_obj_drop_impl(kptr, NULL) + #endif From df57f38a0d081f05ec48ea5aa7ca0564918ed915 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:26:05 +0530 Subject: [PATCH 040/101] bpf: Permit NULL checking pointer with non-zero fixed offset Pointer increment on seeing PTR_MAYBE_NULL is already protected against, hence make an exception for PTR_TO_BTF_ID | MEM_ALLOC while still keeping the warning for other unintended cases that might creep in. bpf_list_pop_{front,_back} helpers planned to be introduced in next commit will return a MEM_ALLOC register with incremented offset pointing to bpf_list_node field. The user is supposed to then obtain the pointer to the entry using container_of after NULL checking it. The current restrictions trigger a warning when doing the NULL checking. Revisiting the reason, it is meant as an assertion which seems to actually work and catch the bad case. Hence, under no other circumstances can reg->off be non-zero for a register that has the PTR_MAYBE_NULL type flag set. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-16-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 1fbb0b51c429..a339a39d895c 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -10791,16 +10791,19 @@ static void mark_ptr_or_null_reg(struct bpf_func_state *state, { if (type_may_be_null(reg->type) && reg->id == id && !WARN_ON_ONCE(!reg->id)) { - if (WARN_ON_ONCE(reg->smin_value || reg->smax_value || - !tnum_equals_const(reg->var_off, 0) || - reg->off)) { - /* Old offset (both fixed and variable parts) should - * have been known-zero, because we don't allow pointer - * arithmetic on pointers that might be NULL. If we - * see this happening, don't convert the register. - */ + /* Old offset (both fixed and variable parts) should have been + * known-zero, because we don't allow pointer arithmetic on + * pointers that might be NULL. If we see this happening, don't + * convert the register. + * + * But in some cases, some helpers that return local kptrs + * advance offset for the returned pointer. In those cases, it + * is fine to expect to see reg->off. + */ + if (WARN_ON_ONCE(reg->smin_value || reg->smax_value || !tnum_equals_const(reg->var_off, 0))) + return; + if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC | PTR_MAYBE_NULL) && WARN_ON_ONCE(reg->off)) return; - } if (is_null) { reg->type = SCALAR_VALUE; /* We don't need id and ref_obj_id from this point From 8cab76ec634995e59a8b6346bf8b835ab7fad3a3 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:26:06 +0530 Subject: [PATCH 041/101] bpf: Introduce single ownership BPF linked list API Add a linked list API for use in BPF programs, where it expects protection from the bpf_spin_lock in the same allocation as the bpf_list_head. For now, only one bpf_spin_lock can be present hence that is assumed to be the one protecting the bpf_list_head. The following functions are added to kick things off: // Add node to beginning of list void bpf_list_push_front(struct bpf_list_head *head, struct bpf_list_node *node); // Add node to end of list void bpf_list_push_back(struct bpf_list_head *head, struct bpf_list_node *node); // Remove node at beginning of list and return it struct bpf_list_node *bpf_list_pop_front(struct bpf_list_head *head); // Remove node at end of list and return it struct bpf_list_node *bpf_list_pop_back(struct bpf_list_head *head); The lock protecting the bpf_list_head needs to be taken for all operations. The verifier ensures that the lock that needs to be taken is always held, and only the correct lock is taken for these operations. These checks are made statically by relying on the reg->id preserved for registers pointing into regions having both bpf_spin_lock and the objects protected by it. The comment over check_reg_allocation_locked in this change describes the logic in detail. Note that bpf_list_push_front and bpf_list_push_back are meant to consume the object containing the node in the 1st argument, however that specific mechanism is intended to not release the ref_obj_id directly until the bpf_spin_unlock is called. In this commit, nothing is done, but the next commit will be introducing logic to handle this case, so it has been left as is for now. bpf_list_pop_front and bpf_list_pop_back delete the first or last item of the list respectively, and return pointer to the element at the list_node offset. The user can then use container_of style macro to get the actual entry type. The verifier however statically knows the actual type, so the safety properties are still preserved. With these additions, programs can now manage their own linked lists and store their objects in them. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-17-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/helpers.c | 55 +++- kernel/bpf/verifier.c | 275 +++++++++++++++++- .../testing/selftests/bpf/bpf_experimental.h | 28 ++ 3 files changed, 349 insertions(+), 9 deletions(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 71d803ca0c1d..212e791d7452 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1780,6 +1780,50 @@ void bpf_obj_drop_impl(void *p__alloc, void *meta__ign) bpf_mem_free(&bpf_global_ma, p); } +static void __bpf_list_add(struct bpf_list_node *node, struct bpf_list_head *head, bool tail) +{ + struct list_head *n = (void *)node, *h = (void *)head; + + if (unlikely(!h->next)) + INIT_LIST_HEAD(h); + if (unlikely(!n->next)) + INIT_LIST_HEAD(n); + tail ? list_add_tail(n, h) : list_add(n, h); +} + +void bpf_list_push_front(struct bpf_list_head *head, struct bpf_list_node *node) +{ + return __bpf_list_add(node, head, false); +} + +void bpf_list_push_back(struct bpf_list_head *head, struct bpf_list_node *node) +{ + return __bpf_list_add(node, head, true); +} + +static struct bpf_list_node *__bpf_list_del(struct bpf_list_head *head, bool tail) +{ + struct list_head *n, *h = (void *)head; + + if (unlikely(!h->next)) + INIT_LIST_HEAD(h); + if (list_empty(h)) + return NULL; + n = tail ? h->prev : h->next; + list_del_init(n); + return (struct bpf_list_node *)n; +} + +struct bpf_list_node *bpf_list_pop_front(struct bpf_list_head *head) +{ + return __bpf_list_del(head, false); +} + +struct bpf_list_node *bpf_list_pop_back(struct bpf_list_head *head) +{ + return __bpf_list_del(head, true); +} + __diag_pop(); BTF_SET8_START(generic_btf_ids) @@ -1788,6 +1832,10 @@ BTF_ID_FLAGS(func, crash_kexec, KF_DESTRUCTIVE) #endif BTF_ID_FLAGS(func, bpf_obj_new_impl, KF_ACQUIRE | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_obj_drop_impl, KF_RELEASE) +BTF_ID_FLAGS(func, bpf_list_push_front) +BTF_ID_FLAGS(func, bpf_list_push_back) +BTF_ID_FLAGS(func, bpf_list_pop_front, KF_ACQUIRE | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_list_pop_back, KF_ACQUIRE | KF_RET_NULL) BTF_SET8_END(generic_btf_ids) static const struct btf_kfunc_id_set generic_kfunc_set = { @@ -1797,7 +1845,12 @@ static const struct btf_kfunc_id_set generic_kfunc_set = { static int __init kfunc_init(void) { - return register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &generic_kfunc_set); + int ret; + + ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &generic_kfunc_set); + if (ret) + return ret; + return register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &generic_kfunc_set); } late_initcall(kfunc_init); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index a339a39d895c..1364df74129e 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -7883,6 +7883,9 @@ struct bpf_kfunc_call_arg_meta { struct btf *btf; u32 btf_id; } arg_obj_drop; + struct { + struct btf_field *field; + } arg_list_head; }; static bool is_kfunc_acquire(struct bpf_kfunc_call_arg_meta *meta) @@ -7987,13 +7990,17 @@ static bool is_kfunc_arg_scalar_with_name(const struct btf *btf, enum { KF_ARG_DYNPTR_ID, + KF_ARG_LIST_HEAD_ID, + KF_ARG_LIST_NODE_ID, }; BTF_ID_LIST(kf_arg_btf_ids) BTF_ID(struct, bpf_dynptr_kern) +BTF_ID(struct, bpf_list_head) +BTF_ID(struct, bpf_list_node) -static bool is_kfunc_arg_dynptr(const struct btf *btf, - const struct btf_param *arg) +static bool __is_kfunc_ptr_arg_type(const struct btf *btf, + const struct btf_param *arg, int type) { const struct btf_type *t; u32 res_id; @@ -8006,7 +8013,22 @@ static bool is_kfunc_arg_dynptr(const struct btf *btf, t = btf_type_skip_modifiers(btf, t->type, &res_id); if (!t) return false; - return btf_types_are_same(btf, res_id, btf_vmlinux, kf_arg_btf_ids[KF_ARG_DYNPTR_ID]); + return btf_types_are_same(btf, res_id, btf_vmlinux, kf_arg_btf_ids[type]); +} + +static bool is_kfunc_arg_dynptr(const struct btf *btf, const struct btf_param *arg) +{ + return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_DYNPTR_ID); +} + +static bool is_kfunc_arg_list_head(const struct btf *btf, const struct btf_param *arg) +{ + return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_LIST_HEAD_ID); +} + +static bool is_kfunc_arg_list_node(const struct btf *btf, const struct btf_param *arg) +{ + return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_LIST_NODE_ID); } /* Returns true if struct is composed of scalars, 4 levels of nesting allowed */ @@ -8063,6 +8085,8 @@ enum kfunc_ptr_arg_type { KF_ARG_PTR_TO_ALLOC_BTF_ID, /* Allocated object */ KF_ARG_PTR_TO_KPTR, /* PTR_TO_KPTR but type specific */ KF_ARG_PTR_TO_DYNPTR, + KF_ARG_PTR_TO_LIST_HEAD, + KF_ARG_PTR_TO_LIST_NODE, KF_ARG_PTR_TO_BTF_ID, /* Also covers reg2btf_ids conversions */ KF_ARG_PTR_TO_MEM, KF_ARG_PTR_TO_MEM_SIZE, /* Size derived from next argument, skip it */ @@ -8071,16 +8095,28 @@ enum kfunc_ptr_arg_type { enum special_kfunc_type { KF_bpf_obj_new_impl, KF_bpf_obj_drop_impl, + KF_bpf_list_push_front, + KF_bpf_list_push_back, + KF_bpf_list_pop_front, + KF_bpf_list_pop_back, }; BTF_SET_START(special_kfunc_set) BTF_ID(func, bpf_obj_new_impl) BTF_ID(func, bpf_obj_drop_impl) +BTF_ID(func, bpf_list_push_front) +BTF_ID(func, bpf_list_push_back) +BTF_ID(func, bpf_list_pop_front) +BTF_ID(func, bpf_list_pop_back) BTF_SET_END(special_kfunc_set) BTF_ID_LIST(special_kfunc_list) BTF_ID(func, bpf_obj_new_impl) BTF_ID(func, bpf_obj_drop_impl) +BTF_ID(func, bpf_list_push_front) +BTF_ID(func, bpf_list_push_back) +BTF_ID(func, bpf_list_pop_front) +BTF_ID(func, bpf_list_pop_back) static enum kfunc_ptr_arg_type get_kfunc_ptr_arg_type(struct bpf_verifier_env *env, @@ -8123,6 +8159,12 @@ get_kfunc_ptr_arg_type(struct bpf_verifier_env *env, if (is_kfunc_arg_dynptr(meta->btf, &args[argno])) return KF_ARG_PTR_TO_DYNPTR; + if (is_kfunc_arg_list_head(meta->btf, &args[argno])) + return KF_ARG_PTR_TO_LIST_HEAD; + + if (is_kfunc_arg_list_node(meta->btf, &args[argno])) + return KF_ARG_PTR_TO_LIST_NODE; + if ((base_type(reg->type) == PTR_TO_BTF_ID || reg2btf_ids[base_type(reg->type)])) { if (!btf_type_is_struct(ref_t)) { verbose(env, "kernel function %s args#%d pointer type %s %s is not supported\n", @@ -8218,6 +8260,182 @@ static int process_kf_arg_ptr_to_kptr(struct bpf_verifier_env *env, return 0; } +/* Implementation details: + * + * Each register points to some region of memory, which we define as an + * allocation. Each allocation may embed a bpf_spin_lock which protects any + * special BPF objects (bpf_list_head, bpf_rb_root, etc.) part of the same + * allocation. The lock and the data it protects are colocated in the same + * memory region. + * + * Hence, everytime a register holds a pointer value pointing to such + * allocation, the verifier preserves a unique reg->id for it. + * + * The verifier remembers the lock 'ptr' and the lock 'id' whenever + * bpf_spin_lock is called. + * + * To enable this, lock state in the verifier captures two values: + * active_lock.ptr = Register's type specific pointer + * active_lock.id = A unique ID for each register pointer value + * + * Currently, PTR_TO_MAP_VALUE and PTR_TO_BTF_ID | MEM_ALLOC are the two + * supported register types. + * + * The active_lock.ptr in case of map values is the reg->map_ptr, and in case of + * allocated objects is the reg->btf pointer. + * + * The active_lock.id is non-unique for maps supporting direct_value_addr, as we + * can establish the provenance of the map value statically for each distinct + * lookup into such maps. They always contain a single map value hence unique + * IDs for each pseudo load pessimizes the algorithm and rejects valid programs. + * + * So, in case of global variables, they use array maps with max_entries = 1, + * hence their active_lock.ptr becomes map_ptr and id = 0 (since they all point + * into the same map value as max_entries is 1, as described above). + * + * In case of inner map lookups, the inner map pointer has same map_ptr as the + * outer map pointer (in verifier context), but each lookup into an inner map + * assigns a fresh reg->id to the lookup, so while lookups into distinct inner + * maps from the same outer map share the same map_ptr as active_lock.ptr, they + * will get different reg->id assigned to each lookup, hence different + * active_lock.id. + * + * In case of allocated objects, active_lock.ptr is the reg->btf, and the + * reg->id is a unique ID preserved after the NULL pointer check on the pointer + * returned from bpf_obj_new. Each allocation receives a new reg->id. + */ +static int check_reg_allocation_locked(struct bpf_verifier_env *env, struct bpf_reg_state *reg) +{ + void *ptr; + u32 id; + + switch ((int)reg->type) { + case PTR_TO_MAP_VALUE: + ptr = reg->map_ptr; + break; + case PTR_TO_BTF_ID | MEM_ALLOC: + ptr = reg->btf; + break; + default: + verbose(env, "verifier internal error: unknown reg type for lock check\n"); + return -EFAULT; + } + id = reg->id; + + if (!env->cur_state->active_lock.ptr) + return -EINVAL; + if (env->cur_state->active_lock.ptr != ptr || + env->cur_state->active_lock.id != id) { + verbose(env, "held lock and object are not in the same allocation\n"); + return -EINVAL; + } + return 0; +} + +static bool is_bpf_list_api_kfunc(u32 btf_id) +{ + return btf_id == special_kfunc_list[KF_bpf_list_push_front] || + btf_id == special_kfunc_list[KF_bpf_list_push_back] || + btf_id == special_kfunc_list[KF_bpf_list_pop_front] || + btf_id == special_kfunc_list[KF_bpf_list_pop_back]; +} + +static int process_kf_arg_ptr_to_list_head(struct bpf_verifier_env *env, + struct bpf_reg_state *reg, u32 regno, + struct bpf_kfunc_call_arg_meta *meta) +{ + struct btf_field *field; + struct btf_record *rec; + u32 list_head_off; + + if (meta->btf != btf_vmlinux || !is_bpf_list_api_kfunc(meta->func_id)) { + verbose(env, "verifier internal error: bpf_list_head argument for unknown kfunc\n"); + return -EFAULT; + } + + if (!tnum_is_const(reg->var_off)) { + verbose(env, + "R%d doesn't have constant offset. bpf_list_head has to be at the constant offset\n", + regno); + return -EINVAL; + } + + rec = reg_btf_record(reg); + list_head_off = reg->off + reg->var_off.value; + field = btf_record_find(rec, list_head_off, BPF_LIST_HEAD); + if (!field) { + verbose(env, "bpf_list_head not found at offset=%u\n", list_head_off); + return -EINVAL; + } + + /* All functions require bpf_list_head to be protected using a bpf_spin_lock */ + if (check_reg_allocation_locked(env, reg)) { + verbose(env, "bpf_spin_lock at off=%d must be held for bpf_list_head\n", + rec->spin_lock_off); + return -EINVAL; + } + + if (meta->arg_list_head.field) { + verbose(env, "verifier internal error: repeating bpf_list_head arg\n"); + return -EFAULT; + } + meta->arg_list_head.field = field; + return 0; +} + +static int process_kf_arg_ptr_to_list_node(struct bpf_verifier_env *env, + struct bpf_reg_state *reg, u32 regno, + struct bpf_kfunc_call_arg_meta *meta) +{ + const struct btf_type *et, *t; + struct btf_field *field; + struct btf_record *rec; + u32 list_node_off; + + if (meta->btf != btf_vmlinux || + (meta->func_id != special_kfunc_list[KF_bpf_list_push_front] && + meta->func_id != special_kfunc_list[KF_bpf_list_push_back])) { + verbose(env, "verifier internal error: bpf_list_node argument for unknown kfunc\n"); + return -EFAULT; + } + + if (!tnum_is_const(reg->var_off)) { + verbose(env, + "R%d doesn't have constant offset. bpf_list_node has to be at the constant offset\n", + regno); + return -EINVAL; + } + + rec = reg_btf_record(reg); + list_node_off = reg->off + reg->var_off.value; + field = btf_record_find(rec, list_node_off, BPF_LIST_NODE); + if (!field || field->offset != list_node_off) { + verbose(env, "bpf_list_node not found at offset=%u\n", list_node_off); + return -EINVAL; + } + + field = meta->arg_list_head.field; + + et = btf_type_by_id(field->list_head.btf, field->list_head.value_btf_id); + t = btf_type_by_id(reg->btf, reg->btf_id); + if (!btf_struct_ids_match(&env->log, reg->btf, reg->btf_id, 0, field->list_head.btf, + field->list_head.value_btf_id, true)) { + verbose(env, "operation on bpf_list_head expects arg#1 bpf_list_node at offset=%d " + "in struct %s, but arg is at offset=%d in struct %s\n", + field->list_head.node_offset, btf_name_by_offset(field->list_head.btf, et->name_off), + list_node_off, btf_name_by_offset(reg->btf, t->name_off)); + return -EINVAL; + } + + if (list_node_off != field->list_head.node_offset) { + verbose(env, "arg#1 offset=%d, but expected bpf_list_node at offset=%d in struct %s\n", + list_node_off, field->list_head.node_offset, + btf_name_by_offset(field->list_head.btf, et->name_off)); + return -EINVAL; + } + return 0; +} + static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_arg_meta *meta) { const char *func_name = meta->func_name, *ref_tname; @@ -8336,6 +8554,8 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ break; case KF_ARG_PTR_TO_KPTR: case KF_ARG_PTR_TO_DYNPTR: + case KF_ARG_PTR_TO_LIST_HEAD: + case KF_ARG_PTR_TO_LIST_NODE: case KF_ARG_PTR_TO_MEM: case KF_ARG_PTR_TO_MEM_SIZE: /* Trusted by default */ @@ -8400,6 +8620,33 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ return -EINVAL; } break; + case KF_ARG_PTR_TO_LIST_HEAD: + if (reg->type != PTR_TO_MAP_VALUE && + reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) { + verbose(env, "arg#%d expected pointer to map value or allocated object\n", i); + return -EINVAL; + } + if (reg->type == (PTR_TO_BTF_ID | MEM_ALLOC) && !reg->ref_obj_id) { + verbose(env, "allocated object must be referenced\n"); + return -EINVAL; + } + ret = process_kf_arg_ptr_to_list_head(env, reg, regno, meta); + if (ret < 0) + return ret; + break; + case KF_ARG_PTR_TO_LIST_NODE: + if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) { + verbose(env, "arg#%d expected pointer to allocated object\n", i); + return -EINVAL; + } + if (!reg->ref_obj_id) { + verbose(env, "allocated object must be referenced\n"); + return -EINVAL; + } + ret = process_kf_arg_ptr_to_list_node(env, reg, regno, meta); + if (ret < 0) + return ret; + break; case KF_ARG_PTR_TO_BTF_ID: /* Only base_type is checked, further checks are done here */ if (reg->type != PTR_TO_BTF_ID && @@ -8568,6 +8815,15 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, env->insn_aux_data[insn_idx].kptr_struct_meta = btf_find_struct_meta(meta.arg_obj_drop.btf, meta.arg_obj_drop.btf_id); + } else if (meta.func_id == special_kfunc_list[KF_bpf_list_pop_front] || + meta.func_id == special_kfunc_list[KF_bpf_list_pop_back]) { + struct btf_field *field = meta.arg_list_head.field; + + mark_reg_known_zero(env, regs, BPF_REG_0); + regs[BPF_REG_0].type = PTR_TO_BTF_ID | MEM_ALLOC; + regs[BPF_REG_0].btf = field->list_head.btf; + regs[BPF_REG_0].btf_id = field->list_head.value_btf_id; + regs[BPF_REG_0].off = field->list_head.node_offset; } else { verbose(env, "kernel function %s unhandled dynamic return type\n", meta.func_name); @@ -13264,11 +13520,14 @@ static int do_check(struct bpf_verifier_env *env) return -EINVAL; } - if (env->cur_state->active_lock.ptr && - (insn->src_reg == BPF_PSEUDO_CALL || - insn->imm != BPF_FUNC_spin_unlock)) { - verbose(env, "function calls are not allowed while holding a lock\n"); - return -EINVAL; + if (env->cur_state->active_lock.ptr) { + if ((insn->src_reg == BPF_REG_0 && insn->imm != BPF_FUNC_spin_unlock) || + (insn->src_reg == BPF_PSEUDO_CALL) || + (insn->src_reg == BPF_PSEUDO_KFUNC_CALL && + (insn->off != 0 || !is_bpf_list_api_kfunc(insn->imm)))) { + verbose(env, "function calls are not allowed while holding a lock\n"); + return -EINVAL; + } } if (insn->src_reg == BPF_PSEUDO_CALL) err = check_func_call(env, insn, &env->insn_idx); diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h index 8473395a11af..d6b143275e82 100644 --- a/tools/testing/selftests/bpf/bpf_experimental.h +++ b/tools/testing/selftests/bpf/bpf_experimental.h @@ -35,4 +35,32 @@ extern void bpf_obj_drop_impl(void *kptr, void *meta) __ksym; /* Convenience macro to wrap over bpf_obj_drop_impl */ #define bpf_obj_drop(kptr) bpf_obj_drop_impl(kptr, NULL) +/* Description + * Add a new entry to the beginning of the BPF linked list. + * Returns + * Void. + */ +extern void bpf_list_push_front(struct bpf_list_head *head, struct bpf_list_node *node) __ksym; + +/* Description + * Add a new entry to the end of the BPF linked list. + * Returns + * Void. + */ +extern void bpf_list_push_back(struct bpf_list_head *head, struct bpf_list_node *node) __ksym; + +/* Description + * Remove the entry at the beginning of the BPF linked list. + * Returns + * Pointer to bpf_list_node of deleted entry, or NULL if list is empty. + */ +extern struct bpf_list_node *bpf_list_pop_front(struct bpf_list_head *head) __ksym; + +/* Description + * Remove the entry at the end of the BPF linked list. + * Returns + * Pointer to bpf_list_node of deleted entry, or NULL if list is empty. + */ +extern struct bpf_list_node *bpf_list_pop_back(struct bpf_list_head *head) __ksym; + #endif From 534e86bc6c66e1e0c798a1c0a6a680bb231c08db Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:26:07 +0530 Subject: [PATCH 042/101] bpf: Add 'release on unlock' logic for bpf_list_push_{front,back} This commit implements the delayed release logic for bpf_list_push_front and bpf_list_push_back. Once a node has been added to the list, it's pointer changes to PTR_UNTRUSTED. However, it is only released once the lock protecting the list is unlocked. For such PTR_TO_BTF_ID | MEM_ALLOC with PTR_UNTRUSTED set but an active ref_obj_id, it is still permitted to read them as long as the lock is held. Writing to them is not allowed. This allows having read access to push items we no longer own until we release the lock guarding the list, allowing a little more flexibility when working with these APIs. Note that enabling write support has fairly tricky interactions with what happens inside the critical section. Just as an example, currently, bpf_obj_drop is not permitted, but if it were, being able to write to the PTR_UNTRUSTED pointer while the object gets released back to the memory allocator would violate safety properties we wish to guarantee (i.e. not crashing the kernel). The memory could be reused for a different type in the BPF program or even in the kernel as it gets eventually kfree'd. Not enabling bpf_obj_drop inside the critical section would appear to prevent all of the above, but that is more of an artifical limitation right now. Since the write support is tangled with how we handle potential aliasing of nodes inside the critical section that may or may not be part of the list anymore, it has been deferred to a future patch. Acked-by: Dave Marchevsky Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-18-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/linux/bpf_verifier.h | 5 ++++ kernel/bpf/verifier.c | 58 +++++++++++++++++++++++++++++++++++- 2 files changed, 62 insertions(+), 1 deletion(-) diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 3dc72d396dfc..23f30c685f28 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -223,6 +223,11 @@ struct bpf_reference_state { * exiting a callback function. */ int callback_ref; + /* Mark the reference state to release the registers sharing the same id + * on bpf_spin_unlock (for nodes that we will lose ownership to but are + * safe to access inside the critical section). + */ + bool release_on_unlock; }; /* state of the program: diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 1364df74129e..195d24316750 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5652,7 +5652,9 @@ static int process_spin_lock(struct bpf_verifier_env *env, int regno, cur->active_lock.ptr = btf; cur->active_lock.id = reg->id; } else { + struct bpf_func_state *fstate = cur_func(env); void *ptr; + int i; if (map) ptr = map; @@ -5670,6 +5672,23 @@ static int process_spin_lock(struct bpf_verifier_env *env, int regno, } cur->active_lock.ptr = NULL; cur->active_lock.id = 0; + + for (i = 0; i < fstate->acquired_refs; i++) { + int err; + + /* Complain on error because this reference state cannot + * be freed before this point, as bpf_spin_lock critical + * section does not allow functions that release the + * allocated object immediately. + */ + if (!fstate->refs[i].release_on_unlock) + continue; + err = release_reference(env, fstate->refs[i].id); + if (err) { + verbose(env, "failed to release release_on_unlock reference"); + return err; + } + } } return 0; } @@ -8260,6 +8279,42 @@ static int process_kf_arg_ptr_to_kptr(struct bpf_verifier_env *env, return 0; } +static int ref_set_release_on_unlock(struct bpf_verifier_env *env, u32 ref_obj_id) +{ + struct bpf_func_state *state = cur_func(env); + struct bpf_reg_state *reg; + int i; + + /* bpf_spin_lock only allows calling list_push and list_pop, no BPF + * subprogs, no global functions. This means that the references would + * not be released inside the critical section but they may be added to + * the reference state, and the acquired_refs are never copied out for a + * different frame as BPF to BPF calls don't work in bpf_spin_lock + * critical sections. + */ + if (!ref_obj_id) { + verbose(env, "verifier internal error: ref_obj_id is zero for release_on_unlock\n"); + return -EFAULT; + } + for (i = 0; i < state->acquired_refs; i++) { + if (state->refs[i].id == ref_obj_id) { + if (state->refs[i].release_on_unlock) { + verbose(env, "verifier internal error: expected false release_on_unlock"); + return -EFAULT; + } + state->refs[i].release_on_unlock = true; + /* Now mark everyone sharing same ref_obj_id as untrusted */ + bpf_for_each_reg_in_vstate(env->cur_state, state, reg, ({ + if (reg->ref_obj_id == ref_obj_id) + reg->type |= PTR_UNTRUSTED; + })); + return 0; + } + } + verbose(env, "verifier internal error: ref state missing for ref_obj_id\n"); + return -EFAULT; +} + /* Implementation details: * * Each register points to some region of memory, which we define as an @@ -8433,7 +8488,8 @@ static int process_kf_arg_ptr_to_list_node(struct bpf_verifier_env *env, btf_name_by_offset(field->list_head.btf, et->name_off)); return -EINVAL; } - return 0; + /* Set arg#1 for expiration after unlock */ + return ref_set_release_on_unlock(env, reg->ref_obj_id); } static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_arg_meta *meta) From c22dfdd21592c5d56b49d5fba8de300ad7bf293c Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:26:08 +0530 Subject: [PATCH 043/101] bpf: Add comments for map BTF matching requirement for bpf_list_head The old behavior of bpf_map_meta_equal was that it compared timer_off to be equal (but not spin_lock_off, because that was not allowed), and did memcmp of kptr_off_tab. Now, we memcmp the btf_record of two bpf_map structs, which has all fields. We preserve backwards compat as we kzalloc the array, so if only spin lock and timer exist in map, we only compare offset while the rest of unused members in the btf_field struct are zeroed out. In case of kptr, btf and everything else is of vmlinux or module, so as long type is same it will match, since kernel btf, module, dtor pointer will be same across maps. Now with list_head in the mix, things are a bit complicated. We implicitly add a requirement that both BTFs are same, because struct btf_field_list_head has btf and value_rec members. We obviously shouldn't force BTFs to be equal by default, as that breaks backwards compatibility. Currently it is only implicitly required due to list_head matching struct btf and value_rec member. value_rec points back into a btf_record stashed in the map BTF (btf member of btf_field_list_head). So that pointer and btf member has to match exactly. Document all these subtle details so that things don't break in the future when touching this code. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-19-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/btf.c | 3 +++ kernel/bpf/map_in_map.c | 5 +++++ kernel/bpf/syscall.c | 14 ++++++++++++++ 3 files changed, 22 insertions(+) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 4dcda4ae48c1..f7d5fab61535 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -3648,6 +3648,9 @@ struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type return NULL; cnt = ret; + /* This needs to be kzalloc to zero out padding and unused fields, see + * comment in btf_record_equal. + */ rec = kzalloc(offsetof(struct btf_record, fields[cnt]), GFP_KERNEL | __GFP_NOWARN); if (!rec) return ERR_PTR(-ENOMEM); diff --git a/kernel/bpf/map_in_map.c b/kernel/bpf/map_in_map.c index 7cce2047c6ef..38136ec4e095 100644 --- a/kernel/bpf/map_in_map.c +++ b/kernel/bpf/map_in_map.c @@ -68,6 +68,11 @@ struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd) } inner_map_meta->field_offs = field_offs; } + /* Note: We must use the same BTF, as we also used btf_record_dup above + * which relies on BTF being same for both maps, as some members like + * record->fields.list_head have pointers like value_rec pointing into + * inner_map->btf. + */ if (inner_map->btf) { btf_get(inner_map->btf); inner_map_meta->btf = inner_map->btf; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 6140cbc3ed8a..35972afb6850 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -611,6 +611,20 @@ bool btf_record_equal(const struct btf_record *rec_a, const struct btf_record *r if (rec_a->cnt != rec_b->cnt) return false; size = offsetof(struct btf_record, fields[rec_a->cnt]); + /* btf_parse_fields uses kzalloc to allocate a btf_record, so unused + * members are zeroed out. So memcmp is safe to do without worrying + * about padding/unused fields. + * + * While spin_lock, timer, and kptr have no relation to map BTF, + * list_head metadata is specific to map BTF, the btf and value_rec + * members in particular. btf is the map BTF, while value_rec points to + * btf_record in that map BTF. + * + * So while by default, we don't rely on the map BTF (which the records + * were parsed from) matching for both records, which is not backwards + * compatible, in case list_head is part of it, we implicitly rely on + * that by way of depending on memcmp succeeding for it. + */ return !memcmp(rec_a, rec_b, size); } From 64069c72b4b8e44f6876249cc8f2e2ee4d209a93 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:26:09 +0530 Subject: [PATCH 044/101] selftests/bpf: Add __contains macro to bpf_experimental.h Add user facing __contains macro which provides a convenient wrapper over the verbose kernel specific BTF declaration tag required to annotate BPF list head structs in user types. Acked-by: Dave Marchevsky Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-20-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/bpf_experimental.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h index d6b143275e82..424f7bbbfe9b 100644 --- a/tools/testing/selftests/bpf/bpf_experimental.h +++ b/tools/testing/selftests/bpf/bpf_experimental.h @@ -6,6 +6,8 @@ #include #include +#define __contains(name, node) __attribute__((btf_decl_tag("contains:" #name ":" #node))) + /* Description * Allocates an object of the type represented by 'local_type_id' in * program BTF. User may use the bpf_core_type_id_local macro to pass the From d85aedac4dc43deaba7aabc78198d0600bb84887 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:26:10 +0530 Subject: [PATCH 045/101] selftests/bpf: Update spinlock selftest Make updates in preparation for adding more test cases to this selftest: - Convert from CHECK_ to ASSERT macros. - Use BPF skeleton - Fix typo sping -> spin - Rename spinlock.c -> spin_lock.c Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-21-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/prog_tests/spin_lock.c | 49 +++++++++++++++++++ .../selftests/bpf/prog_tests/spinlock.c | 45 ----------------- .../selftests/bpf/progs/test_spin_lock.c | 4 +- 3 files changed, 51 insertions(+), 47 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/spin_lock.c delete mode 100644 tools/testing/selftests/bpf/prog_tests/spinlock.c diff --git a/tools/testing/selftests/bpf/prog_tests/spin_lock.c b/tools/testing/selftests/bpf/prog_tests/spin_lock.c new file mode 100644 index 000000000000..fab061e9d77c --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/spin_lock.c @@ -0,0 +1,49 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include + +#include "test_spin_lock.skel.h" + +static void *spin_lock_thread(void *arg) +{ + int err, prog_fd = *(u32 *) arg; + LIBBPF_OPTS(bpf_test_run_opts, topts, + .data_in = &pkt_v4, + .data_size_in = sizeof(pkt_v4), + .repeat = 10000, + ); + + err = bpf_prog_test_run_opts(prog_fd, &topts); + ASSERT_OK(err, "test_run"); + ASSERT_OK(topts.retval, "test_run retval"); + pthread_exit(arg); +} + +void test_spinlock(void) +{ + struct test_spin_lock *skel; + pthread_t thread_id[4]; + int prog_fd, i; + void *ret; + + skel = test_spin_lock__open_and_load(); + if (!ASSERT_OK_PTR(skel, "test_spin_lock__open_and_load")) + return; + prog_fd = bpf_program__fd(skel->progs.bpf_spin_lock_test); + for (i = 0; i < 4; i++) { + int err; + + err = pthread_create(&thread_id[i], NULL, &spin_lock_thread, &prog_fd); + if (!ASSERT_OK(err, "pthread_create")) + goto end; + } + + for (i = 0; i < 4; i++) { + if (!ASSERT_OK(pthread_join(thread_id[i], &ret), "pthread_join")) + goto end; + if (!ASSERT_EQ(ret, &prog_fd, "ret == prog_fd")) + goto end; + } +end: + test_spin_lock__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/prog_tests/spinlock.c b/tools/testing/selftests/bpf/prog_tests/spinlock.c deleted file mode 100644 index 15eb1372d771..000000000000 --- a/tools/testing/selftests/bpf/prog_tests/spinlock.c +++ /dev/null @@ -1,45 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -#include -#include - -static void *spin_lock_thread(void *arg) -{ - int err, prog_fd = *(u32 *) arg; - LIBBPF_OPTS(bpf_test_run_opts, topts, - .data_in = &pkt_v4, - .data_size_in = sizeof(pkt_v4), - .repeat = 10000, - ); - - err = bpf_prog_test_run_opts(prog_fd, &topts); - ASSERT_OK(err, "test_run"); - ASSERT_OK(topts.retval, "test_run retval"); - pthread_exit(arg); -} - -void test_spinlock(void) -{ - const char *file = "./test_spin_lock.bpf.o"; - pthread_t thread_id[4]; - struct bpf_object *obj = NULL; - int prog_fd; - int err = 0, i; - void *ret; - - err = bpf_prog_test_load(file, BPF_PROG_TYPE_CGROUP_SKB, &obj, &prog_fd); - if (CHECK_FAIL(err)) { - printf("test_spin_lock:bpf_prog_test_load errno %d\n", errno); - goto close_prog; - } - for (i = 0; i < 4; i++) - if (CHECK_FAIL(pthread_create(&thread_id[i], NULL, - &spin_lock_thread, &prog_fd))) - goto close_prog; - - for (i = 0; i < 4; i++) - if (CHECK_FAIL(pthread_join(thread_id[i], &ret) || - ret != (void *)&prog_fd)) - goto close_prog; -close_prog: - bpf_object__close(obj); -} diff --git a/tools/testing/selftests/bpf/progs/test_spin_lock.c b/tools/testing/selftests/bpf/progs/test_spin_lock.c index 7e88309d3229..5bd10409285b 100644 --- a/tools/testing/selftests/bpf/progs/test_spin_lock.c +++ b/tools/testing/selftests/bpf/progs/test_spin_lock.c @@ -45,8 +45,8 @@ struct { #define CREDIT_PER_NS(delta, rate) (((delta) * rate) >> 20) -SEC("tc") -int bpf_sping_lock_test(struct __sk_buff *skb) +SEC("cgroup_skb/ingress") +int bpf_spin_lock_test(struct __sk_buff *skb) { volatile int credit = 0, max_credit = 100, pkt_len = 64; struct hmap_elem zero = {}, *val; From c48748aea4f806587813f02219ca0b4910646c5e Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:26:11 +0530 Subject: [PATCH 046/101] selftests/bpf: Add failure test cases for spin lock pairing First, ensure that whenever a bpf_spin_lock is present in an allocation, the reg->id is preserved. This won't be true for global variables however, since they have a single map value per map, hence the verifier harcodes it to 0 (so that multiple pseudo ldimm64 insns can yield the same lock object per map at a given offset). Next, add test cases for all possible combinations (kptr, global, map value, inner map value). Since we lifted restriction on locking in inner maps, also add test cases for them. Currently, each lookup into an inner map gets a fresh reg->id, so even if the reg->map_ptr is same, they will be treated as separate allocations and the incorrect unlock pairing will be rejected. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-22-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/prog_tests/spin_lock.c | 89 +++++++- .../selftests/bpf/progs/test_spin_lock_fail.c | 204 ++++++++++++++++++ 2 files changed, 292 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/bpf/progs/test_spin_lock_fail.c diff --git a/tools/testing/selftests/bpf/prog_tests/spin_lock.c b/tools/testing/selftests/bpf/prog_tests/spin_lock.c index fab061e9d77c..72282e92a78a 100644 --- a/tools/testing/selftests/bpf/prog_tests/spin_lock.c +++ b/tools/testing/selftests/bpf/prog_tests/spin_lock.c @@ -3,6 +3,79 @@ #include #include "test_spin_lock.skel.h" +#include "test_spin_lock_fail.skel.h" + +static char log_buf[1024 * 1024]; + +static struct { + const char *prog_name; + const char *err_msg; +} spin_lock_fail_tests[] = { + { "lock_id_kptr_preserve", + "5: (bf) r1 = r0 ; R0_w=ptr_foo(id=2,ref_obj_id=2,off=0,imm=0) " + "R1_w=ptr_foo(id=2,ref_obj_id=2,off=0,imm=0) refs=2\n6: (85) call bpf_this_cpu_ptr#154\n" + "R1 type=ptr_ expected=percpu_ptr_" }, + { "lock_id_global_zero", + "; R1_w=map_value(off=0,ks=4,vs=4,imm=0)\n2: (85) call bpf_this_cpu_ptr#154\n" + "R1 type=map_value expected=percpu_ptr_" }, + { "lock_id_mapval_preserve", + "8: (bf) r1 = r0 ; R0_w=map_value(id=1,off=0,ks=4,vs=8,imm=0) " + "R1_w=map_value(id=1,off=0,ks=4,vs=8,imm=0)\n9: (85) call bpf_this_cpu_ptr#154\n" + "R1 type=map_value expected=percpu_ptr_" }, + { "lock_id_innermapval_preserve", + "13: (bf) r1 = r0 ; R0=map_value(id=2,off=0,ks=4,vs=8,imm=0) " + "R1_w=map_value(id=2,off=0,ks=4,vs=8,imm=0)\n14: (85) call bpf_this_cpu_ptr#154\n" + "R1 type=map_value expected=percpu_ptr_" }, + { "lock_id_mismatch_kptr_kptr", "bpf_spin_unlock of different lock" }, + { "lock_id_mismatch_kptr_global", "bpf_spin_unlock of different lock" }, + { "lock_id_mismatch_kptr_mapval", "bpf_spin_unlock of different lock" }, + { "lock_id_mismatch_kptr_innermapval", "bpf_spin_unlock of different lock" }, + { "lock_id_mismatch_global_global", "bpf_spin_unlock of different lock" }, + { "lock_id_mismatch_global_kptr", "bpf_spin_unlock of different lock" }, + { "lock_id_mismatch_global_mapval", "bpf_spin_unlock of different lock" }, + { "lock_id_mismatch_global_innermapval", "bpf_spin_unlock of different lock" }, + { "lock_id_mismatch_mapval_mapval", "bpf_spin_unlock of different lock" }, + { "lock_id_mismatch_mapval_kptr", "bpf_spin_unlock of different lock" }, + { "lock_id_mismatch_mapval_global", "bpf_spin_unlock of different lock" }, + { "lock_id_mismatch_mapval_innermapval", "bpf_spin_unlock of different lock" }, + { "lock_id_mismatch_innermapval_innermapval1", "bpf_spin_unlock of different lock" }, + { "lock_id_mismatch_innermapval_innermapval2", "bpf_spin_unlock of different lock" }, + { "lock_id_mismatch_innermapval_kptr", "bpf_spin_unlock of different lock" }, + { "lock_id_mismatch_innermapval_global", "bpf_spin_unlock of different lock" }, + { "lock_id_mismatch_innermapval_mapval", "bpf_spin_unlock of different lock" }, +}; + +static void test_spin_lock_fail_prog(const char *prog_name, const char *err_msg) +{ + LIBBPF_OPTS(bpf_object_open_opts, opts, .kernel_log_buf = log_buf, + .kernel_log_size = sizeof(log_buf), + .kernel_log_level = 1); + struct test_spin_lock_fail *skel; + struct bpf_program *prog; + int ret; + + skel = test_spin_lock_fail__open_opts(&opts); + if (!ASSERT_OK_PTR(skel, "test_spin_lock_fail__open_opts")) + return; + + prog = bpf_object__find_program_by_name(skel->obj, prog_name); + if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name")) + goto end; + + bpf_program__set_autoload(prog, true); + + ret = test_spin_lock_fail__load(skel); + if (!ASSERT_ERR(ret, "test_spin_lock_fail__load must fail")) + goto end; + + if (!ASSERT_OK_PTR(strstr(log_buf, err_msg), "expected error message")) { + fprintf(stderr, "Expected: %s\n", err_msg); + fprintf(stderr, "Verifier: %s\n", log_buf); + } + +end: + test_spin_lock_fail__destroy(skel); +} static void *spin_lock_thread(void *arg) { @@ -19,7 +92,7 @@ static void *spin_lock_thread(void *arg) pthread_exit(arg); } -void test_spinlock(void) +void test_spin_lock_success(void) { struct test_spin_lock *skel; pthread_t thread_id[4]; @@ -47,3 +120,17 @@ void test_spinlock(void) end: test_spin_lock__destroy(skel); } + +void test_spin_lock(void) +{ + int i; + + test_spin_lock_success(); + + for (i = 0; i < ARRAY_SIZE(spin_lock_fail_tests); i++) { + if (!test__start_subtest(spin_lock_fail_tests[i].prog_name)) + continue; + test_spin_lock_fail_prog(spin_lock_fail_tests[i].prog_name, + spin_lock_fail_tests[i].err_msg); + } +} diff --git a/tools/testing/selftests/bpf/progs/test_spin_lock_fail.c b/tools/testing/selftests/bpf/progs/test_spin_lock_fail.c new file mode 100644 index 000000000000..86cd183ef6dc --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_spin_lock_fail.c @@ -0,0 +1,204 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include "bpf_experimental.h" + +struct foo { + struct bpf_spin_lock lock; + int data; +}; + +struct array_map { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, int); + __type(value, struct foo); + __uint(max_entries, 1); +} array_map SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS); + __uint(max_entries, 1); + __type(key, int); + __type(value, int); + __array(values, struct array_map); +} map_of_maps SEC(".maps") = { + .values = { + [0] = &array_map, + }, +}; + +SEC(".data.A") struct bpf_spin_lock lockA; +SEC(".data.B") struct bpf_spin_lock lockB; + +SEC("?tc") +int lock_id_kptr_preserve(void *ctx) +{ + struct foo *f; + + f = bpf_obj_new(typeof(*f)); + if (!f) + return 0; + bpf_this_cpu_ptr(f); + return 0; +} + +SEC("?tc") +int lock_id_global_zero(void *ctx) +{ + bpf_this_cpu_ptr(&lockA); + return 0; +} + +SEC("?tc") +int lock_id_mapval_preserve(void *ctx) +{ + struct foo *f; + int key = 0; + + f = bpf_map_lookup_elem(&array_map, &key); + if (!f) + return 0; + bpf_this_cpu_ptr(f); + return 0; +} + +SEC("?tc") +int lock_id_innermapval_preserve(void *ctx) +{ + struct foo *f; + int key = 0; + void *map; + + map = bpf_map_lookup_elem(&map_of_maps, &key); + if (!map) + return 0; + f = bpf_map_lookup_elem(map, &key); + if (!f) + return 0; + bpf_this_cpu_ptr(f); + return 0; +} + +#define CHECK(test, A, B) \ + SEC("?tc") \ + int lock_id_mismatch_##test(void *ctx) \ + { \ + struct foo *f1, *f2, *v, *iv; \ + int key = 0; \ + void *map; \ + \ + map = bpf_map_lookup_elem(&map_of_maps, &key); \ + if (!map) \ + return 0; \ + iv = bpf_map_lookup_elem(map, &key); \ + if (!iv) \ + return 0; \ + v = bpf_map_lookup_elem(&array_map, &key); \ + if (!v) \ + return 0; \ + f1 = bpf_obj_new(typeof(*f1)); \ + if (!f1) \ + return 0; \ + f2 = bpf_obj_new(typeof(*f2)); \ + if (!f2) { \ + bpf_obj_drop(f1); \ + return 0; \ + } \ + bpf_spin_lock(A); \ + bpf_spin_unlock(B); \ + return 0; \ + } + +CHECK(kptr_kptr, &f1->lock, &f2->lock); +CHECK(kptr_global, &f1->lock, &lockA); +CHECK(kptr_mapval, &f1->lock, &v->lock); +CHECK(kptr_innermapval, &f1->lock, &iv->lock); + +CHECK(global_global, &lockA, &lockB); +CHECK(global_kptr, &lockA, &f1->lock); +CHECK(global_mapval, &lockA, &v->lock); +CHECK(global_innermapval, &lockA, &iv->lock); + +SEC("?tc") +int lock_id_mismatch_mapval_mapval(void *ctx) +{ + struct foo *f1, *f2; + int key = 0; + + f1 = bpf_map_lookup_elem(&array_map, &key); + if (!f1) + return 0; + f2 = bpf_map_lookup_elem(&array_map, &key); + if (!f2) + return 0; + + bpf_spin_lock(&f1->lock); + f1->data = 42; + bpf_spin_unlock(&f2->lock); + + return 0; +} + +CHECK(mapval_kptr, &v->lock, &f1->lock); +CHECK(mapval_global, &v->lock, &lockB); +CHECK(mapval_innermapval, &v->lock, &iv->lock); + +SEC("?tc") +int lock_id_mismatch_innermapval_innermapval1(void *ctx) +{ + struct foo *f1, *f2; + int key = 0; + void *map; + + map = bpf_map_lookup_elem(&map_of_maps, &key); + if (!map) + return 0; + f1 = bpf_map_lookup_elem(map, &key); + if (!f1) + return 0; + f2 = bpf_map_lookup_elem(map, &key); + if (!f2) + return 0; + + bpf_spin_lock(&f1->lock); + f1->data = 42; + bpf_spin_unlock(&f2->lock); + + return 0; +} + +SEC("?tc") +int lock_id_mismatch_innermapval_innermapval2(void *ctx) +{ + struct foo *f1, *f2; + int key = 0; + void *map; + + map = bpf_map_lookup_elem(&map_of_maps, &key); + if (!map) + return 0; + f1 = bpf_map_lookup_elem(map, &key); + if (!f1) + return 0; + map = bpf_map_lookup_elem(&map_of_maps, &key); + if (!map) + return 0; + f2 = bpf_map_lookup_elem(map, &key); + if (!f2) + return 0; + + bpf_spin_lock(&f1->lock); + f1->data = 42; + bpf_spin_unlock(&f2->lock); + + return 0; +} + +CHECK(innermapval_kptr, &iv->lock, &f1->lock); +CHECK(innermapval_global, &iv->lock, &lockA); +CHECK(innermapval_mapval, &iv->lock, &v->lock); + +#undef CHECK + +char _license[] SEC("license") = "GPL"; From 300f19dcdb99b708353d9e46fd660a4765ab277d Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:26:12 +0530 Subject: [PATCH 047/101] selftests/bpf: Add BPF linked list API tests Include various tests covering the success and failure cases. Also, run the success cases at runtime to verify correctness of linked list manipulation routines, in addition to ensuring successful verification. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-23-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/DENYLIST.aarch64 | 1 + tools/testing/selftests/bpf/DENYLIST.s390x | 1 + .../selftests/bpf/prog_tests/linked_list.c | 255 ++++++++ .../testing/selftests/bpf/progs/linked_list.c | 370 +++++++++++ .../testing/selftests/bpf/progs/linked_list.h | 56 ++ .../selftests/bpf/progs/linked_list_fail.c | 581 ++++++++++++++++++ 6 files changed, 1264 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/linked_list.c create mode 100644 tools/testing/selftests/bpf/progs/linked_list.c create mode 100644 tools/testing/selftests/bpf/progs/linked_list.h create mode 100644 tools/testing/selftests/bpf/progs/linked_list_fail.c diff --git a/tools/testing/selftests/bpf/DENYLIST.aarch64 b/tools/testing/selftests/bpf/DENYLIST.aarch64 index 09416d5d2e33..affc5aebbf0f 100644 --- a/tools/testing/selftests/bpf/DENYLIST.aarch64 +++ b/tools/testing/selftests/bpf/DENYLIST.aarch64 @@ -38,6 +38,7 @@ kprobe_multi_test/skel_api # kprobe_multi__attach unexpect ksyms_module/libbpf # 'bpf_testmod_ksym_percpu': not found in kernel BTF ksyms_module/lskel # test_ksyms_module_lskel__open_and_load unexpected error: -2 libbpf_get_fd_by_id_opts # test_libbpf_get_fd_by_id_opts__attach unexpected error: -524 (errno 524) +linked_list lookup_key # test_lookup_key__attach unexpected error: -524 (errno 524) lru_bug # lru_bug__attach unexpected error: -524 (errno 524) modify_return # modify_return__attach failed unexpected error: -524 (errno 524) diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x index be4e3d47ea3e..072243af93b0 100644 --- a/tools/testing/selftests/bpf/DENYLIST.s390x +++ b/tools/testing/selftests/bpf/DENYLIST.s390x @@ -33,6 +33,7 @@ ksyms_module # test_ksyms_module__open_and_load unex ksyms_module_libbpf # JIT does not support calling kernel function (kfunc) ksyms_module_lskel # test_ksyms_module_lskel__open_and_load unexpected error: -9 (?) libbpf_get_fd_by_id_opts # failed to attach: ERROR: strerror_r(-524)=22 (trampoline) +linked_list # JIT does not support calling kernel function (kfunc) lookup_key # JIT does not support calling kernel function (kfunc) lru_bug # prog 'printk': failed to auto-attach: -524 map_kptr # failed to open_and_load program: -524 (trampoline) diff --git a/tools/testing/selftests/bpf/prog_tests/linked_list.c b/tools/testing/selftests/bpf/prog_tests/linked_list.c new file mode 100644 index 000000000000..41e588807321 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/linked_list.c @@ -0,0 +1,255 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include + +#include "linked_list.skel.h" +#include "linked_list_fail.skel.h" + +static char log_buf[1024 * 1024]; + +static struct { + const char *prog_name; + const char *err_msg; +} linked_list_fail_tests[] = { +#define TEST(test, off) \ + { #test "_missing_lock_push_front", \ + "bpf_spin_lock at off=" #off " must be held for bpf_list_head" }, \ + { #test "_missing_lock_push_back", \ + "bpf_spin_lock at off=" #off " must be held for bpf_list_head" }, \ + { #test "_missing_lock_pop_front", \ + "bpf_spin_lock at off=" #off " must be held for bpf_list_head" }, \ + { #test "_missing_lock_pop_back", \ + "bpf_spin_lock at off=" #off " must be held for bpf_list_head" }, + TEST(kptr, 32) + TEST(global, 16) + TEST(map, 0) + TEST(inner_map, 0) +#undef TEST +#define TEST(test, op) \ + { #test "_kptr_incorrect_lock_" #op, \ + "held lock and object are not in the same allocation\n" \ + "bpf_spin_lock at off=32 must be held for bpf_list_head" }, \ + { #test "_global_incorrect_lock_" #op, \ + "held lock and object are not in the same allocation\n" \ + "bpf_spin_lock at off=16 must be held for bpf_list_head" }, \ + { #test "_map_incorrect_lock_" #op, \ + "held lock and object are not in the same allocation\n" \ + "bpf_spin_lock at off=0 must be held for bpf_list_head" }, \ + { #test "_inner_map_incorrect_lock_" #op, \ + "held lock and object are not in the same allocation\n" \ + "bpf_spin_lock at off=0 must be held for bpf_list_head" }, + TEST(kptr, push_front) + TEST(kptr, push_back) + TEST(kptr, pop_front) + TEST(kptr, pop_back) + TEST(global, push_front) + TEST(global, push_back) + TEST(global, pop_front) + TEST(global, pop_back) + TEST(map, push_front) + TEST(map, push_back) + TEST(map, pop_front) + TEST(map, pop_back) + TEST(inner_map, push_front) + TEST(inner_map, push_back) + TEST(inner_map, pop_front) + TEST(inner_map, pop_back) +#undef TEST + { "map_compat_kprobe", "tracing progs cannot use bpf_list_head yet" }, + { "map_compat_kretprobe", "tracing progs cannot use bpf_list_head yet" }, + { "map_compat_tp", "tracing progs cannot use bpf_list_head yet" }, + { "map_compat_perf", "tracing progs cannot use bpf_list_head yet" }, + { "map_compat_raw_tp", "tracing progs cannot use bpf_list_head yet" }, + { "map_compat_raw_tp_w", "tracing progs cannot use bpf_list_head yet" }, + { "obj_type_id_oor", "local type ID argument must be in range [0, U32_MAX]" }, + { "obj_new_no_composite", "bpf_obj_new type ID argument must be of a struct" }, + { "obj_new_no_struct", "bpf_obj_new type ID argument must be of a struct" }, + { "obj_drop_non_zero_off", "R1 must have zero offset when passed to release func" }, + { "new_null_ret", "R0 invalid mem access 'ptr_or_null_'" }, + { "obj_new_acq", "Unreleased reference id=" }, + { "use_after_drop", "invalid mem access 'scalar'" }, + { "ptr_walk_scalar", "type=scalar expected=percpu_ptr_" }, + { "direct_read_lock", "direct access to bpf_spin_lock is disallowed" }, + { "direct_write_lock", "direct access to bpf_spin_lock is disallowed" }, + { "direct_read_head", "direct access to bpf_list_head is disallowed" }, + { "direct_write_head", "direct access to bpf_list_head is disallowed" }, + { "direct_read_node", "direct access to bpf_list_node is disallowed" }, + { "direct_write_node", "direct access to bpf_list_node is disallowed" }, + { "write_after_push_front", "only read is supported" }, + { "write_after_push_back", "only read is supported" }, + { "use_after_unlock_push_front", "invalid mem access 'scalar'" }, + { "use_after_unlock_push_back", "invalid mem access 'scalar'" }, + { "double_push_front", "arg#1 expected pointer to allocated object" }, + { "double_push_back", "arg#1 expected pointer to allocated object" }, + { "no_node_value_type", "bpf_list_node not found at offset=0" }, + { "incorrect_value_type", + "operation on bpf_list_head expects arg#1 bpf_list_node at offset=0 in struct foo, " + "but arg is at offset=0 in struct bar" }, + { "incorrect_node_var_off", "variable ptr_ access var_off=(0x0; 0xffffffff) disallowed" }, + { "incorrect_node_off1", "bpf_list_node not found at offset=1" }, + { "incorrect_node_off2", "arg#1 offset=40, but expected bpf_list_node at offset=0 in struct foo" }, + { "no_head_type", "bpf_list_head not found at offset=0" }, + { "incorrect_head_var_off1", "R1 doesn't have constant offset" }, + { "incorrect_head_var_off2", "variable ptr_ access var_off=(0x0; 0xffffffff) disallowed" }, + { "incorrect_head_off1", "bpf_list_head not found at offset=17" }, + { "incorrect_head_off2", "bpf_list_head not found at offset=1" }, + { "pop_front_off", + "15: (bf) r1 = r6 ; R1_w=ptr_or_null_foo(id=4,ref_obj_id=4,off=40,imm=0) " + "R6_w=ptr_or_null_foo(id=4,ref_obj_id=4,off=40,imm=0) refs=2,4\n" + "16: (85) call bpf_this_cpu_ptr#154\nR1 type=ptr_or_null_ expected=percpu_ptr_" }, + { "pop_back_off", + "15: (bf) r1 = r6 ; R1_w=ptr_or_null_foo(id=4,ref_obj_id=4,off=40,imm=0) " + "R6_w=ptr_or_null_foo(id=4,ref_obj_id=4,off=40,imm=0) refs=2,4\n" + "16: (85) call bpf_this_cpu_ptr#154\nR1 type=ptr_or_null_ expected=percpu_ptr_" }, +}; + +static void test_linked_list_fail_prog(const char *prog_name, const char *err_msg) +{ + LIBBPF_OPTS(bpf_object_open_opts, opts, .kernel_log_buf = log_buf, + .kernel_log_size = sizeof(log_buf), + .kernel_log_level = 1); + struct linked_list_fail *skel; + struct bpf_program *prog; + int ret; + + skel = linked_list_fail__open_opts(&opts); + if (!ASSERT_OK_PTR(skel, "linked_list_fail__open_opts")) + return; + + prog = bpf_object__find_program_by_name(skel->obj, prog_name); + if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name")) + goto end; + + bpf_program__set_autoload(prog, true); + + ret = linked_list_fail__load(skel); + if (!ASSERT_ERR(ret, "linked_list_fail__load must fail")) + goto end; + + if (!ASSERT_OK_PTR(strstr(log_buf, err_msg), "expected error message")) { + fprintf(stderr, "Expected: %s\n", err_msg); + fprintf(stderr, "Verifier: %s\n", log_buf); + } + +end: + linked_list_fail__destroy(skel); +} + +static void clear_fields(struct bpf_map *map) +{ + char buf[24]; + int key = 0; + + memset(buf, 0xff, sizeof(buf)); + ASSERT_OK(bpf_map__update_elem(map, &key, sizeof(key), buf, sizeof(buf), 0), "check_and_free_fields"); +} + +enum { + TEST_ALL, + PUSH_POP, + PUSH_POP_MULT, + LIST_IN_LIST, +}; + +static void test_linked_list_success(int mode, bool leave_in_map) +{ + LIBBPF_OPTS(bpf_test_run_opts, opts, + .data_in = &pkt_v4, + .data_size_in = sizeof(pkt_v4), + .repeat = 1, + ); + struct linked_list *skel; + int ret; + + skel = linked_list__open_and_load(); + if (!ASSERT_OK_PTR(skel, "linked_list__open_and_load")) + return; + + if (mode == LIST_IN_LIST) + goto lil; + if (mode == PUSH_POP_MULT) + goto ppm; + + ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.map_list_push_pop), &opts); + ASSERT_OK(ret, "map_list_push_pop"); + ASSERT_OK(opts.retval, "map_list_push_pop retval"); + if (!leave_in_map) + clear_fields(skel->maps.array_map); + + ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.inner_map_list_push_pop), &opts); + ASSERT_OK(ret, "inner_map_list_push_pop"); + ASSERT_OK(opts.retval, "inner_map_list_push_pop retval"); + if (!leave_in_map) + clear_fields(skel->maps.inner_map); + + ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.global_list_push_pop), &opts); + ASSERT_OK(ret, "global_list_push_pop"); + ASSERT_OK(opts.retval, "global_list_push_pop retval"); + if (!leave_in_map) + clear_fields(skel->maps.data_A); + + if (mode == PUSH_POP) + goto end; + +ppm: + ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.map_list_push_pop_multiple), &opts); + ASSERT_OK(ret, "map_list_push_pop_multiple"); + ASSERT_OK(opts.retval, "map_list_push_pop_multiple retval"); + if (!leave_in_map) + clear_fields(skel->maps.array_map); + + ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.inner_map_list_push_pop_multiple), &opts); + ASSERT_OK(ret, "inner_map_list_push_pop_multiple"); + ASSERT_OK(opts.retval, "inner_map_list_push_pop_multiple retval"); + if (!leave_in_map) + clear_fields(skel->maps.inner_map); + + ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.global_list_push_pop_multiple), &opts); + ASSERT_OK(ret, "global_list_push_pop_multiple"); + ASSERT_OK(opts.retval, "global_list_push_pop_multiple retval"); + if (!leave_in_map) + clear_fields(skel->maps.data_A); + + if (mode == PUSH_POP_MULT) + goto end; + +lil: + ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.map_list_in_list), &opts); + ASSERT_OK(ret, "map_list_in_list"); + ASSERT_OK(opts.retval, "map_list_in_list retval"); + if (!leave_in_map) + clear_fields(skel->maps.array_map); + + ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.inner_map_list_in_list), &opts); + ASSERT_OK(ret, "inner_map_list_in_list"); + ASSERT_OK(opts.retval, "inner_map_list_in_list retval"); + if (!leave_in_map) + clear_fields(skel->maps.inner_map); + + ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.global_list_in_list), &opts); + ASSERT_OK(ret, "global_list_in_list"); + ASSERT_OK(opts.retval, "global_list_in_list retval"); + if (!leave_in_map) + clear_fields(skel->maps.data_A); +end: + linked_list__destroy(skel); +} + +void test_linked_list(void) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(linked_list_fail_tests); i++) { + if (!test__start_subtest(linked_list_fail_tests[i].prog_name)) + continue; + test_linked_list_fail_prog(linked_list_fail_tests[i].prog_name, + linked_list_fail_tests[i].err_msg); + } + test_linked_list_success(PUSH_POP, false); + test_linked_list_success(PUSH_POP, true); + test_linked_list_success(PUSH_POP_MULT, false); + test_linked_list_success(PUSH_POP_MULT, true); + test_linked_list_success(LIST_IN_LIST, false); + test_linked_list_success(LIST_IN_LIST, true); + test_linked_list_success(TEST_ALL, false); +} diff --git a/tools/testing/selftests/bpf/progs/linked_list.c b/tools/testing/selftests/bpf/progs/linked_list.c new file mode 100644 index 000000000000..2c7b615c6d41 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/linked_list.c @@ -0,0 +1,370 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include "bpf_experimental.h" + +#ifndef ARRAY_SIZE +#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) +#endif + +#include "linked_list.h" + +static __always_inline +int list_push_pop(struct bpf_spin_lock *lock, struct bpf_list_head *head, bool leave_in_map) +{ + struct bpf_list_node *n; + struct foo *f; + + f = bpf_obj_new(typeof(*f)); + if (!f) + return 2; + + bpf_spin_lock(lock); + n = bpf_list_pop_front(head); + bpf_spin_unlock(lock); + if (n) { + bpf_obj_drop(container_of(n, struct foo, node)); + bpf_obj_drop(f); + return 3; + } + + bpf_spin_lock(lock); + n = bpf_list_pop_back(head); + bpf_spin_unlock(lock); + if (n) { + bpf_obj_drop(container_of(n, struct foo, node)); + bpf_obj_drop(f); + return 4; + } + + + bpf_spin_lock(lock); + f->data = 42; + bpf_list_push_front(head, &f->node); + bpf_spin_unlock(lock); + if (leave_in_map) + return 0; + bpf_spin_lock(lock); + n = bpf_list_pop_back(head); + bpf_spin_unlock(lock); + if (!n) + return 5; + f = container_of(n, struct foo, node); + if (f->data != 42) { + bpf_obj_drop(f); + return 6; + } + + bpf_spin_lock(lock); + f->data = 13; + bpf_list_push_front(head, &f->node); + bpf_spin_unlock(lock); + bpf_spin_lock(lock); + n = bpf_list_pop_front(head); + bpf_spin_unlock(lock); + if (!n) + return 7; + f = container_of(n, struct foo, node); + if (f->data != 13) { + bpf_obj_drop(f); + return 8; + } + bpf_obj_drop(f); + + bpf_spin_lock(lock); + n = bpf_list_pop_front(head); + bpf_spin_unlock(lock); + if (n) { + bpf_obj_drop(container_of(n, struct foo, node)); + return 9; + } + + bpf_spin_lock(lock); + n = bpf_list_pop_back(head); + bpf_spin_unlock(lock); + if (n) { + bpf_obj_drop(container_of(n, struct foo, node)); + return 10; + } + return 0; +} + + +static __always_inline +int list_push_pop_multiple(struct bpf_spin_lock *lock, struct bpf_list_head *head, bool leave_in_map) +{ + struct bpf_list_node *n; + struct foo *f[8], *pf; + int i; + + for (i = 0; i < ARRAY_SIZE(f); i++) { + f[i] = bpf_obj_new(typeof(**f)); + if (!f[i]) + return 2; + f[i]->data = i; + bpf_spin_lock(lock); + bpf_list_push_front(head, &f[i]->node); + bpf_spin_unlock(lock); + } + + for (i = 0; i < ARRAY_SIZE(f); i++) { + bpf_spin_lock(lock); + n = bpf_list_pop_front(head); + bpf_spin_unlock(lock); + if (!n) + return 3; + pf = container_of(n, struct foo, node); + if (pf->data != (ARRAY_SIZE(f) - i - 1)) { + bpf_obj_drop(pf); + return 4; + } + bpf_spin_lock(lock); + bpf_list_push_back(head, &pf->node); + bpf_spin_unlock(lock); + } + + if (leave_in_map) + return 0; + + for (i = 0; i < ARRAY_SIZE(f); i++) { + bpf_spin_lock(lock); + n = bpf_list_pop_back(head); + bpf_spin_unlock(lock); + if (!n) + return 5; + pf = container_of(n, struct foo, node); + if (pf->data != i) { + bpf_obj_drop(pf); + return 6; + } + bpf_obj_drop(pf); + } + bpf_spin_lock(lock); + n = bpf_list_pop_back(head); + bpf_spin_unlock(lock); + if (n) { + bpf_obj_drop(container_of(n, struct foo, node)); + return 7; + } + + bpf_spin_lock(lock); + n = bpf_list_pop_front(head); + bpf_spin_unlock(lock); + if (n) { + bpf_obj_drop(container_of(n, struct foo, node)); + return 8; + } + return 0; +} + +static __always_inline +int list_in_list(struct bpf_spin_lock *lock, struct bpf_list_head *head, bool leave_in_map) +{ + struct bpf_list_node *n; + struct bar *ba[8], *b; + struct foo *f; + int i; + + f = bpf_obj_new(typeof(*f)); + if (!f) + return 2; + for (i = 0; i < ARRAY_SIZE(ba); i++) { + b = bpf_obj_new(typeof(*b)); + if (!b) { + bpf_obj_drop(f); + return 3; + } + b->data = i; + bpf_spin_lock(&f->lock); + bpf_list_push_back(&f->head, &b->node); + bpf_spin_unlock(&f->lock); + } + + bpf_spin_lock(lock); + f->data = 42; + bpf_list_push_front(head, &f->node); + bpf_spin_unlock(lock); + + if (leave_in_map) + return 0; + + bpf_spin_lock(lock); + n = bpf_list_pop_front(head); + bpf_spin_unlock(lock); + if (!n) + return 4; + f = container_of(n, struct foo, node); + if (f->data != 42) { + bpf_obj_drop(f); + return 5; + } + + for (i = 0; i < ARRAY_SIZE(ba); i++) { + bpf_spin_lock(&f->lock); + n = bpf_list_pop_front(&f->head); + bpf_spin_unlock(&f->lock); + if (!n) { + bpf_obj_drop(f); + return 6; + } + b = container_of(n, struct bar, node); + if (b->data != i) { + bpf_obj_drop(f); + bpf_obj_drop(b); + return 7; + } + bpf_obj_drop(b); + } + bpf_spin_lock(&f->lock); + n = bpf_list_pop_front(&f->head); + bpf_spin_unlock(&f->lock); + if (n) { + bpf_obj_drop(f); + bpf_obj_drop(container_of(n, struct bar, node)); + return 8; + } + bpf_obj_drop(f); + return 0; +} + +static __always_inline +int test_list_push_pop(struct bpf_spin_lock *lock, struct bpf_list_head *head) +{ + int ret; + + ret = list_push_pop(lock, head, false); + if (ret) + return ret; + return list_push_pop(lock, head, true); +} + +static __always_inline +int test_list_push_pop_multiple(struct bpf_spin_lock *lock, struct bpf_list_head *head) +{ + int ret; + + ret = list_push_pop_multiple(lock ,head, false); + if (ret) + return ret; + return list_push_pop_multiple(lock, head, true); +} + +static __always_inline +int test_list_in_list(struct bpf_spin_lock *lock, struct bpf_list_head *head) +{ + int ret; + + ret = list_in_list(lock, head, false); + if (ret) + return ret; + return list_in_list(lock, head, true); +} + +SEC("tc") +int map_list_push_pop(void *ctx) +{ + struct map_value *v; + + v = bpf_map_lookup_elem(&array_map, &(int){0}); + if (!v) + return 1; + return test_list_push_pop(&v->lock, &v->head); +} + +SEC("tc") +int inner_map_list_push_pop(void *ctx) +{ + struct map_value *v; + void *map; + + map = bpf_map_lookup_elem(&map_of_maps, &(int){0}); + if (!map) + return 1; + v = bpf_map_lookup_elem(map, &(int){0}); + if (!v) + return 1; + return test_list_push_pop(&v->lock, &v->head); +} + +SEC("tc") +int global_list_push_pop(void *ctx) +{ + return test_list_push_pop(&glock, &ghead); +} + +SEC("tc") +int map_list_push_pop_multiple(void *ctx) +{ + struct map_value *v; + int ret; + + v = bpf_map_lookup_elem(&array_map, &(int){0}); + if (!v) + return 1; + return test_list_push_pop_multiple(&v->lock, &v->head); +} + +SEC("tc") +int inner_map_list_push_pop_multiple(void *ctx) +{ + struct map_value *v; + void *map; + int ret; + + map = bpf_map_lookup_elem(&map_of_maps, &(int){0}); + if (!map) + return 1; + v = bpf_map_lookup_elem(map, &(int){0}); + if (!v) + return 1; + return test_list_push_pop_multiple(&v->lock, &v->head); +} + +SEC("tc") +int global_list_push_pop_multiple(void *ctx) +{ + int ret; + + ret = list_push_pop_multiple(&glock, &ghead, false); + if (ret) + return ret; + return list_push_pop_multiple(&glock, &ghead, true); +} + +SEC("tc") +int map_list_in_list(void *ctx) +{ + struct map_value *v; + int ret; + + v = bpf_map_lookup_elem(&array_map, &(int){0}); + if (!v) + return 1; + return test_list_in_list(&v->lock, &v->head); +} + +SEC("tc") +int inner_map_list_in_list(void *ctx) +{ + struct map_value *v; + void *map; + int ret; + + map = bpf_map_lookup_elem(&map_of_maps, &(int){0}); + if (!map) + return 1; + v = bpf_map_lookup_elem(map, &(int){0}); + if (!v) + return 1; + return test_list_in_list(&v->lock, &v->head); +} + +SEC("tc") +int global_list_in_list(void *ctx) +{ + return test_list_in_list(&glock, &ghead); +} + +char _license[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/progs/linked_list.h b/tools/testing/selftests/bpf/progs/linked_list.h new file mode 100644 index 000000000000..8db80ed64db1 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/linked_list.h @@ -0,0 +1,56 @@ +// SPDX-License-Identifier: GPL-2.0 +#ifndef LINKED_LIST_H +#define LINKED_LIST_H + +#include +#include +#include "bpf_experimental.h" + +struct bar { + struct bpf_list_node node; + int data; +}; + +struct foo { + struct bpf_list_node node; + struct bpf_list_head head __contains(bar, node); + struct bpf_spin_lock lock; + int data; + struct bpf_list_node node2; +}; + +struct map_value { + struct bpf_spin_lock lock; + int data; + struct bpf_list_head head __contains(foo, node); +}; + +struct array_map { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, int); + __type(value, struct map_value); + __uint(max_entries, 1); +}; + +struct array_map array_map SEC(".maps"); +struct array_map inner_map SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS); + __uint(max_entries, 1); + __type(key, int); + __type(value, int); + __array(values, struct array_map); +} map_of_maps SEC(".maps") = { + .values = { + [0] = &inner_map, + }, +}; + +#define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8))) + +private(A) struct bpf_spin_lock glock; +private(A) struct bpf_list_head ghead __contains(foo, node); +private(B) struct bpf_spin_lock glock2; + +#endif diff --git a/tools/testing/selftests/bpf/progs/linked_list_fail.c b/tools/testing/selftests/bpf/progs/linked_list_fail.c new file mode 100644 index 000000000000..1d9017240e19 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/linked_list_fail.c @@ -0,0 +1,581 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include "bpf_experimental.h" + +#include "linked_list.h" + +#define INIT \ + struct map_value *v, *v2, *iv, *iv2; \ + struct foo *f, *f1, *f2; \ + struct bar *b; \ + void *map; \ + \ + map = bpf_map_lookup_elem(&map_of_maps, &(int){ 0 }); \ + if (!map) \ + return 0; \ + v = bpf_map_lookup_elem(&array_map, &(int){ 0 }); \ + if (!v) \ + return 0; \ + v2 = bpf_map_lookup_elem(&array_map, &(int){ 0 }); \ + if (!v2) \ + return 0; \ + iv = bpf_map_lookup_elem(map, &(int){ 0 }); \ + if (!iv) \ + return 0; \ + iv2 = bpf_map_lookup_elem(map, &(int){ 0 }); \ + if (!iv2) \ + return 0; \ + f = bpf_obj_new(typeof(*f)); \ + if (!f) \ + return 0; \ + f1 = f; \ + f2 = bpf_obj_new(typeof(*f2)); \ + if (!f2) { \ + bpf_obj_drop(f1); \ + return 0; \ + } \ + b = bpf_obj_new(typeof(*b)); \ + if (!b) { \ + bpf_obj_drop(f2); \ + bpf_obj_drop(f1); \ + return 0; \ + } + +#define CHECK(test, op, hexpr) \ + SEC("?tc") \ + int test##_missing_lock_##op(void *ctx) \ + { \ + INIT; \ + void (*p)(void *) = (void *)&bpf_list_##op; \ + p(hexpr); \ + return 0; \ + } + +CHECK(kptr, push_front, &f->head); +CHECK(kptr, push_back, &f->head); +CHECK(kptr, pop_front, &f->head); +CHECK(kptr, pop_back, &f->head); + +CHECK(global, push_front, &ghead); +CHECK(global, push_back, &ghead); +CHECK(global, pop_front, &ghead); +CHECK(global, pop_back, &ghead); + +CHECK(map, push_front, &v->head); +CHECK(map, push_back, &v->head); +CHECK(map, pop_front, &v->head); +CHECK(map, pop_back, &v->head); + +CHECK(inner_map, push_front, &iv->head); +CHECK(inner_map, push_back, &iv->head); +CHECK(inner_map, pop_front, &iv->head); +CHECK(inner_map, pop_back, &iv->head); + +#undef CHECK + +#define CHECK(test, op, lexpr, hexpr) \ + SEC("?tc") \ + int test##_incorrect_lock_##op(void *ctx) \ + { \ + INIT; \ + void (*p)(void *) = (void *)&bpf_list_##op; \ + bpf_spin_lock(lexpr); \ + p(hexpr); \ + return 0; \ + } + +#define CHECK_OP(op) \ + CHECK(kptr_kptr, op, &f1->lock, &f2->head); \ + CHECK(kptr_global, op, &f1->lock, &ghead); \ + CHECK(kptr_map, op, &f1->lock, &v->head); \ + CHECK(kptr_inner_map, op, &f1->lock, &iv->head); \ + \ + CHECK(global_global, op, &glock2, &ghead); \ + CHECK(global_kptr, op, &glock, &f1->head); \ + CHECK(global_map, op, &glock, &v->head); \ + CHECK(global_inner_map, op, &glock, &iv->head); \ + \ + CHECK(map_map, op, &v->lock, &v2->head); \ + CHECK(map_kptr, op, &v->lock, &f2->head); \ + CHECK(map_global, op, &v->lock, &ghead); \ + CHECK(map_inner_map, op, &v->lock, &iv->head); \ + \ + CHECK(inner_map_inner_map, op, &iv->lock, &iv2->head); \ + CHECK(inner_map_kptr, op, &iv->lock, &f2->head); \ + CHECK(inner_map_global, op, &iv->lock, &ghead); \ + CHECK(inner_map_map, op, &iv->lock, &v->head); + +CHECK_OP(push_front); +CHECK_OP(push_back); +CHECK_OP(pop_front); +CHECK_OP(pop_back); + +#undef CHECK +#undef CHECK_OP +#undef INIT + +SEC("?kprobe/xyz") +int map_compat_kprobe(void *ctx) +{ + bpf_list_push_front(&ghead, NULL); + return 0; +} + +SEC("?kretprobe/xyz") +int map_compat_kretprobe(void *ctx) +{ + bpf_list_push_front(&ghead, NULL); + return 0; +} + +SEC("?tracepoint/xyz") +int map_compat_tp(void *ctx) +{ + bpf_list_push_front(&ghead, NULL); + return 0; +} + +SEC("?perf_event") +int map_compat_perf(void *ctx) +{ + bpf_list_push_front(&ghead, NULL); + return 0; +} + +SEC("?raw_tp/xyz") +int map_compat_raw_tp(void *ctx) +{ + bpf_list_push_front(&ghead, NULL); + return 0; +} + +SEC("?raw_tp.w/xyz") +int map_compat_raw_tp_w(void *ctx) +{ + bpf_list_push_front(&ghead, NULL); + return 0; +} + +SEC("?tc") +int obj_type_id_oor(void *ctx) +{ + bpf_obj_new_impl(~0UL, NULL); + return 0; +} + +SEC("?tc") +int obj_new_no_composite(void *ctx) +{ + bpf_obj_new_impl(bpf_core_type_id_local(int), (void *)42); + return 0; +} + +SEC("?tc") +int obj_new_no_struct(void *ctx) +{ + + bpf_obj_new(union { int data; unsigned udata; }); + return 0; +} + +SEC("?tc") +int obj_drop_non_zero_off(void *ctx) +{ + void *f; + + f = bpf_obj_new(struct foo); + if (!f) + return 0; + bpf_obj_drop(f+1); + return 0; +} + +SEC("?tc") +int new_null_ret(void *ctx) +{ + return bpf_obj_new(struct foo)->data; +} + +SEC("?tc") +int obj_new_acq(void *ctx) +{ + bpf_obj_new(struct foo); + return 0; +} + +SEC("?tc") +int use_after_drop(void *ctx) +{ + struct foo *f; + + f = bpf_obj_new(typeof(*f)); + if (!f) + return 0; + bpf_obj_drop(f); + return f->data; +} + +SEC("?tc") +int ptr_walk_scalar(void *ctx) +{ + struct test1 { + struct test2 { + struct test2 *next; + } *ptr; + } *p; + + p = bpf_obj_new(typeof(*p)); + if (!p) + return 0; + bpf_this_cpu_ptr(p->ptr); + return 0; +} + +SEC("?tc") +int direct_read_lock(void *ctx) +{ + struct foo *f; + + f = bpf_obj_new(typeof(*f)); + if (!f) + return 0; + return *(int *)&f->lock; +} + +SEC("?tc") +int direct_write_lock(void *ctx) +{ + struct foo *f; + + f = bpf_obj_new(typeof(*f)); + if (!f) + return 0; + *(int *)&f->lock = 0; + return 0; +} + +SEC("?tc") +int direct_read_head(void *ctx) +{ + struct foo *f; + + f = bpf_obj_new(typeof(*f)); + if (!f) + return 0; + return *(int *)&f->head; +} + +SEC("?tc") +int direct_write_head(void *ctx) +{ + struct foo *f; + + f = bpf_obj_new(typeof(*f)); + if (!f) + return 0; + *(int *)&f->head = 0; + return 0; +} + +SEC("?tc") +int direct_read_node(void *ctx) +{ + struct foo *f; + + f = bpf_obj_new(typeof(*f)); + if (!f) + return 0; + return *(int *)&f->node; +} + +SEC("?tc") +int direct_write_node(void *ctx) +{ + struct foo *f; + + f = bpf_obj_new(typeof(*f)); + if (!f) + return 0; + *(int *)&f->node = 0; + return 0; +} + +static __always_inline +int write_after_op(void (*push_op)(void *head, void *node)) +{ + struct foo *f; + + f = bpf_obj_new(typeof(*f)); + if (!f) + return 0; + bpf_spin_lock(&glock); + push_op(&ghead, &f->node); + f->data = 42; + bpf_spin_unlock(&glock); + + return 0; +} + +SEC("?tc") +int write_after_push_front(void *ctx) +{ + return write_after_op((void *)bpf_list_push_front); +} + +SEC("?tc") +int write_after_push_back(void *ctx) +{ + return write_after_op((void *)bpf_list_push_back); +} + +static __always_inline +int use_after_unlock(void (*op)(void *head, void *node)) +{ + struct foo *f; + + f = bpf_obj_new(typeof(*f)); + if (!f) + return 0; + bpf_spin_lock(&glock); + f->data = 42; + op(&ghead, &f->node); + bpf_spin_unlock(&glock); + + return f->data; +} + +SEC("?tc") +int use_after_unlock_push_front(void *ctx) +{ + return use_after_unlock((void *)bpf_list_push_front); +} + +SEC("?tc") +int use_after_unlock_push_back(void *ctx) +{ + return use_after_unlock((void *)bpf_list_push_back); +} + +static __always_inline +int list_double_add(void (*op)(void *head, void *node)) +{ + struct foo *f; + + f = bpf_obj_new(typeof(*f)); + if (!f) + return 0; + bpf_spin_lock(&glock); + op(&ghead, &f->node); + op(&ghead, &f->node); + bpf_spin_unlock(&glock); + + return 0; +} + +SEC("?tc") +int double_push_front(void *ctx) +{ + return list_double_add((void *)bpf_list_push_front); +} + +SEC("?tc") +int double_push_back(void *ctx) +{ + return list_double_add((void *)bpf_list_push_back); +} + +SEC("?tc") +int no_node_value_type(void *ctx) +{ + void *p; + + p = bpf_obj_new(struct { int data; }); + if (!p) + return 0; + bpf_spin_lock(&glock); + bpf_list_push_front(&ghead, p); + bpf_spin_unlock(&glock); + + return 0; +} + +SEC("?tc") +int incorrect_value_type(void *ctx) +{ + struct bar *b; + + b = bpf_obj_new(typeof(*b)); + if (!b) + return 0; + bpf_spin_lock(&glock); + bpf_list_push_front(&ghead, &b->node); + bpf_spin_unlock(&glock); + + return 0; +} + +SEC("?tc") +int incorrect_node_var_off(struct __sk_buff *ctx) +{ + struct foo *f; + + f = bpf_obj_new(typeof(*f)); + if (!f) + return 0; + bpf_spin_lock(&glock); + bpf_list_push_front(&ghead, (void *)&f->node + ctx->protocol); + bpf_spin_unlock(&glock); + + return 0; +} + +SEC("?tc") +int incorrect_node_off1(void *ctx) +{ + struct foo *f; + + f = bpf_obj_new(typeof(*f)); + if (!f) + return 0; + bpf_spin_lock(&glock); + bpf_list_push_front(&ghead, (void *)&f->node + 1); + bpf_spin_unlock(&glock); + + return 0; +} + +SEC("?tc") +int incorrect_node_off2(void *ctx) +{ + struct foo *f; + + f = bpf_obj_new(typeof(*f)); + if (!f) + return 0; + bpf_spin_lock(&glock); + bpf_list_push_front(&ghead, &f->node2); + bpf_spin_unlock(&glock); + + return 0; +} + +SEC("?tc") +int no_head_type(void *ctx) +{ + void *p; + + p = bpf_obj_new(typeof(struct { int data; })); + if (!p) + return 0; + bpf_spin_lock(&glock); + bpf_list_push_front(p, NULL); + bpf_spin_lock(&glock); + + return 0; +} + +SEC("?tc") +int incorrect_head_var_off1(struct __sk_buff *ctx) +{ + struct foo *f; + + f = bpf_obj_new(typeof(*f)); + if (!f) + return 0; + bpf_spin_lock(&glock); + bpf_list_push_front((void *)&ghead + ctx->protocol, &f->node); + bpf_spin_unlock(&glock); + + return 0; +} + +SEC("?tc") +int incorrect_head_var_off2(struct __sk_buff *ctx) +{ + struct foo *f; + + f = bpf_obj_new(typeof(*f)); + if (!f) + return 0; + bpf_spin_lock(&glock); + bpf_list_push_front((void *)&f->head + ctx->protocol, &f->node); + bpf_spin_unlock(&glock); + + return 0; +} + +SEC("?tc") +int incorrect_head_off1(void *ctx) +{ + struct foo *f; + struct bar *b; + + f = bpf_obj_new(typeof(*f)); + if (!f) + return 0; + b = bpf_obj_new(typeof(*b)); + if (!b) { + bpf_obj_drop(f); + return 0; + } + + bpf_spin_lock(&f->lock); + bpf_list_push_front((void *)&f->head + 1, &b->node); + bpf_spin_unlock(&f->lock); + + return 0; +} + +SEC("?tc") +int incorrect_head_off2(void *ctx) +{ + struct foo *f; + struct bar *b; + + f = bpf_obj_new(typeof(*f)); + if (!f) + return 0; + + bpf_spin_lock(&glock); + bpf_list_push_front((void *)&ghead + 1, &f->node); + bpf_spin_unlock(&glock); + + return 0; +} + +static __always_inline +int pop_ptr_off(void *(*op)(void *head)) +{ + struct { + struct bpf_list_head head __contains(foo, node2); + struct bpf_spin_lock lock; + } *p; + struct bpf_list_node *n; + + p = bpf_obj_new(typeof(*p)); + if (!p) + return 0; + bpf_spin_lock(&p->lock); + n = op(&p->head); + bpf_spin_unlock(&p->lock); + + bpf_this_cpu_ptr(n); + return 0; +} + +SEC("?tc") +int pop_front_off(void *ctx) +{ + return pop_ptr_off((void *)bpf_list_pop_front); +} + +SEC("?tc") +int pop_back_off(void *ctx) +{ + return pop_ptr_off((void *)bpf_list_pop_back); +} + +char _license[] SEC("license") = "GPL"; From dc2df7bf4c8a24a55ef02ef45dd3e49abc105f76 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:26:13 +0530 Subject: [PATCH 048/101] selftests/bpf: Add BTF sanity tests Preparing the metadata for bpf_list_head involves a complicated parsing step and type resolution for the contained value. Ensure that corner cases are tested against and invalid specifications in source are duly rejected. Also include tests for incorrect ownership relationships in the BTF. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-24-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/prog_tests/linked_list.c | 485 ++++++++++++++++++ 1 file changed, 485 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/linked_list.c b/tools/testing/selftests/bpf/prog_tests/linked_list.c index 41e588807321..dd73d0a62c6e 100644 --- a/tools/testing/selftests/bpf/prog_tests/linked_list.c +++ b/tools/testing/selftests/bpf/prog_tests/linked_list.c @@ -1,4 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 +#include +#include +#include #include #include @@ -235,6 +238,487 @@ end: linked_list__destroy(skel); } +#define SPIN_LOCK 2 +#define LIST_HEAD 3 +#define LIST_NODE 4 + +static struct btf *init_btf(void) +{ + int id, lid, hid, nid; + struct btf *btf; + + btf = btf__new_empty(); + if (!ASSERT_OK_PTR(btf, "btf__new_empty")) + return NULL; + id = btf__add_int(btf, "int", 4, BTF_INT_SIGNED); + if (!ASSERT_EQ(id, 1, "btf__add_int")) + goto end; + lid = btf__add_struct(btf, "bpf_spin_lock", 4); + if (!ASSERT_EQ(lid, SPIN_LOCK, "btf__add_struct bpf_spin_lock")) + goto end; + hid = btf__add_struct(btf, "bpf_list_head", 16); + if (!ASSERT_EQ(hid, LIST_HEAD, "btf__add_struct bpf_list_head")) + goto end; + nid = btf__add_struct(btf, "bpf_list_node", 16); + if (!ASSERT_EQ(nid, LIST_NODE, "btf__add_struct bpf_list_node")) + goto end; + return btf; +end: + btf__free(btf); + return NULL; +} + +static void test_btf(void) +{ + struct btf *btf = NULL; + int id, err; + + while (test__start_subtest("btf: too many locks")) { + btf = init_btf(); + if (!ASSERT_OK_PTR(btf, "init_btf")) + break; + id = btf__add_struct(btf, "foo", 24); + if (!ASSERT_EQ(id, 5, "btf__add_struct foo")) + break; + err = btf__add_field(btf, "a", SPIN_LOCK, 0, 0); + if (!ASSERT_OK(err, "btf__add_struct foo::a")) + break; + err = btf__add_field(btf, "b", SPIN_LOCK, 32, 0); + if (!ASSERT_OK(err, "btf__add_struct foo::a")) + break; + err = btf__add_field(btf, "c", LIST_HEAD, 64, 0); + if (!ASSERT_OK(err, "btf__add_struct foo::a")) + break; + + err = btf__load_into_kernel(btf); + ASSERT_EQ(err, -E2BIG, "check btf"); + btf__free(btf); + break; + } + + while (test__start_subtest("btf: missing lock")) { + btf = init_btf(); + if (!ASSERT_OK_PTR(btf, "init_btf")) + break; + id = btf__add_struct(btf, "foo", 16); + if (!ASSERT_EQ(id, 5, "btf__add_struct foo")) + break; + err = btf__add_field(btf, "a", LIST_HEAD, 0, 0); + if (!ASSERT_OK(err, "btf__add_struct foo::a")) + break; + id = btf__add_decl_tag(btf, "contains:baz:a", 5, 0); + if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:baz:a")) + break; + id = btf__add_struct(btf, "baz", 16); + if (!ASSERT_EQ(id, 7, "btf__add_struct baz")) + break; + err = btf__add_field(btf, "a", LIST_NODE, 0, 0); + if (!ASSERT_OK(err, "btf__add_field baz::a")) + break; + + err = btf__load_into_kernel(btf); + ASSERT_EQ(err, -EINVAL, "check btf"); + btf__free(btf); + break; + } + + while (test__start_subtest("btf: bad offset")) { + btf = init_btf(); + if (!ASSERT_OK_PTR(btf, "init_btf")) + break; + id = btf__add_struct(btf, "foo", 36); + if (!ASSERT_EQ(id, 5, "btf__add_struct foo")) + break; + err = btf__add_field(btf, "a", LIST_HEAD, 0, 0); + if (!ASSERT_OK(err, "btf__add_field foo::a")) + break; + err = btf__add_field(btf, "b", LIST_NODE, 0, 0); + if (!ASSERT_OK(err, "btf__add_field foo::b")) + break; + err = btf__add_field(btf, "c", SPIN_LOCK, 0, 0); + if (!ASSERT_OK(err, "btf__add_field foo::c")) + break; + id = btf__add_decl_tag(btf, "contains:foo:b", 5, 0); + if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:foo:b")) + break; + + err = btf__load_into_kernel(btf); + ASSERT_EQ(err, -EEXIST, "check btf"); + btf__free(btf); + break; + } + + while (test__start_subtest("btf: missing contains:")) { + btf = init_btf(); + if (!ASSERT_OK_PTR(btf, "init_btf")) + break; + id = btf__add_struct(btf, "foo", 24); + if (!ASSERT_EQ(id, 5, "btf__add_struct foo")) + break; + err = btf__add_field(btf, "a", SPIN_LOCK, 0, 0); + if (!ASSERT_OK(err, "btf__add_field foo::a")) + break; + err = btf__add_field(btf, "b", LIST_HEAD, 64, 0); + if (!ASSERT_OK(err, "btf__add_field foo::b")) + break; + + err = btf__load_into_kernel(btf); + ASSERT_EQ(err, -EINVAL, "check btf"); + btf__free(btf); + break; + } + + while (test__start_subtest("btf: missing struct")) { + btf = init_btf(); + if (!ASSERT_OK_PTR(btf, "init_btf")) + break; + id = btf__add_struct(btf, "foo", 24); + if (!ASSERT_EQ(id, 5, "btf__add_struct foo")) + break; + err = btf__add_field(btf, "a", SPIN_LOCK, 0, 0); + if (!ASSERT_OK(err, "btf__add_field foo::a")) + break; + err = btf__add_field(btf, "b", LIST_HEAD, 64, 0); + if (!ASSERT_OK(err, "btf__add_field foo::b")) + break; + id = btf__add_decl_tag(btf, "contains:bar:bar", 5, 1); + if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:bar:bar")) + break; + + err = btf__load_into_kernel(btf); + ASSERT_EQ(err, -ENOENT, "check btf"); + btf__free(btf); + break; + } + + while (test__start_subtest("btf: missing node")) { + btf = init_btf(); + if (!ASSERT_OK_PTR(btf, "init_btf")) + break; + id = btf__add_struct(btf, "foo", 24); + if (!ASSERT_EQ(id, 5, "btf__add_struct foo")) + break; + err = btf__add_field(btf, "a", SPIN_LOCK, 0, 0); + if (!ASSERT_OK(err, "btf__add_field foo::a")) + break; + err = btf__add_field(btf, "b", LIST_HEAD, 64, 0); + if (!ASSERT_OK(err, "btf__add_field foo::b")) + break; + id = btf__add_decl_tag(btf, "contains:foo:c", 5, 1); + if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:foo:c")) + break; + + err = btf__load_into_kernel(btf); + btf__free(btf); + ASSERT_EQ(err, -ENOENT, "check btf"); + break; + } + + while (test__start_subtest("btf: node incorrect type")) { + btf = init_btf(); + if (!ASSERT_OK_PTR(btf, "init_btf")) + break; + id = btf__add_struct(btf, "foo", 20); + if (!ASSERT_EQ(id, 5, "btf__add_struct foo")) + break; + err = btf__add_field(btf, "a", LIST_HEAD, 0, 0); + if (!ASSERT_OK(err, "btf__add_field foo::a")) + break; + err = btf__add_field(btf, "b", SPIN_LOCK, 128, 0); + if (!ASSERT_OK(err, "btf__add_field foo::b")) + break; + id = btf__add_decl_tag(btf, "contains:bar:a", 5, 0); + if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:bar:a")) + break; + id = btf__add_struct(btf, "bar", 4); + if (!ASSERT_EQ(id, 7, "btf__add_struct bar")) + break; + err = btf__add_field(btf, "a", SPIN_LOCK, 0, 0); + if (!ASSERT_OK(err, "btf__add_field bar::a")) + break; + + err = btf__load_into_kernel(btf); + ASSERT_EQ(err, -EINVAL, "check btf"); + btf__free(btf); + break; + } + + while (test__start_subtest("btf: multiple bpf_list_node with name b")) { + btf = init_btf(); + if (!ASSERT_OK_PTR(btf, "init_btf")) + break; + id = btf__add_struct(btf, "foo", 52); + if (!ASSERT_EQ(id, 5, "btf__add_struct foo")) + break; + err = btf__add_field(btf, "a", LIST_HEAD, 0, 0); + if (!ASSERT_OK(err, "btf__add_field foo::a")) + break; + err = btf__add_field(btf, "b", LIST_NODE, 128, 0); + if (!ASSERT_OK(err, "btf__add_field foo::b")) + break; + err = btf__add_field(btf, "b", LIST_NODE, 256, 0); + if (!ASSERT_OK(err, "btf__add_field foo::c")) + break; + err = btf__add_field(btf, "d", SPIN_LOCK, 384, 0); + if (!ASSERT_OK(err, "btf__add_field foo::d")) + break; + id = btf__add_decl_tag(btf, "contains:foo:b", 5, 0); + if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:foo:b")) + break; + + err = btf__load_into_kernel(btf); + ASSERT_EQ(err, -EINVAL, "check btf"); + btf__free(btf); + break; + } + + while (test__start_subtest("btf: owning | owned AA cycle")) { + btf = init_btf(); + if (!ASSERT_OK_PTR(btf, "init_btf")) + break; + id = btf__add_struct(btf, "foo", 36); + if (!ASSERT_EQ(id, 5, "btf__add_struct foo")) + break; + err = btf__add_field(btf, "a", LIST_HEAD, 0, 0); + if (!ASSERT_OK(err, "btf__add_field foo::a")) + break; + err = btf__add_field(btf, "b", LIST_NODE, 128, 0); + if (!ASSERT_OK(err, "btf__add_field foo::b")) + break; + err = btf__add_field(btf, "c", SPIN_LOCK, 256, 0); + if (!ASSERT_OK(err, "btf__add_field foo::c")) + break; + id = btf__add_decl_tag(btf, "contains:foo:b", 5, 0); + if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:foo:b")) + break; + + err = btf__load_into_kernel(btf); + ASSERT_EQ(err, -ELOOP, "check btf"); + btf__free(btf); + break; + } + + while (test__start_subtest("btf: owning | owned ABA cycle")) { + btf = init_btf(); + if (!ASSERT_OK_PTR(btf, "init_btf")) + break; + id = btf__add_struct(btf, "foo", 36); + if (!ASSERT_EQ(id, 5, "btf__add_struct foo")) + break; + err = btf__add_field(btf, "a", LIST_HEAD, 0, 0); + if (!ASSERT_OK(err, "btf__add_field foo::a")) + break; + err = btf__add_field(btf, "b", LIST_NODE, 128, 0); + if (!ASSERT_OK(err, "btf__add_field foo::b")) + break; + err = btf__add_field(btf, "c", SPIN_LOCK, 256, 0); + if (!ASSERT_OK(err, "btf__add_field foo::c")) + break; + id = btf__add_decl_tag(btf, "contains:bar:b", 5, 0); + if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:bar:b")) + break; + id = btf__add_struct(btf, "bar", 36); + if (!ASSERT_EQ(id, 7, "btf__add_struct bar")) + break; + err = btf__add_field(btf, "a", LIST_HEAD, 0, 0); + if (!ASSERT_OK(err, "btf__add_field bar::a")) + break; + err = btf__add_field(btf, "b", LIST_NODE, 128, 0); + if (!ASSERT_OK(err, "btf__add_field bar::b")) + break; + err = btf__add_field(btf, "c", SPIN_LOCK, 256, 0); + if (!ASSERT_OK(err, "btf__add_field bar::c")) + break; + id = btf__add_decl_tag(btf, "contains:foo:b", 7, 0); + if (!ASSERT_EQ(id, 8, "btf__add_decl_tag contains:foo:b")) + break; + + err = btf__load_into_kernel(btf); + ASSERT_EQ(err, -ELOOP, "check btf"); + btf__free(btf); + break; + } + + while (test__start_subtest("btf: owning -> owned")) { + btf = init_btf(); + if (!ASSERT_OK_PTR(btf, "init_btf")) + break; + id = btf__add_struct(btf, "foo", 20); + if (!ASSERT_EQ(id, 5, "btf__add_struct foo")) + break; + err = btf__add_field(btf, "a", LIST_HEAD, 0, 0); + if (!ASSERT_OK(err, "btf__add_field foo::a")) + break; + err = btf__add_field(btf, "b", SPIN_LOCK, 128, 0); + if (!ASSERT_OK(err, "btf__add_field foo::b")) + break; + id = btf__add_decl_tag(btf, "contains:bar:a", 5, 0); + if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:bar:a")) + break; + id = btf__add_struct(btf, "bar", 16); + if (!ASSERT_EQ(id, 7, "btf__add_struct bar")) + break; + err = btf__add_field(btf, "a", LIST_NODE, 0, 0); + if (!ASSERT_OK(err, "btf__add_field bar::a")) + break; + + err = btf__load_into_kernel(btf); + ASSERT_EQ(err, 0, "check btf"); + btf__free(btf); + break; + } + + while (test__start_subtest("btf: owning -> owning | owned -> owned")) { + btf = init_btf(); + if (!ASSERT_OK_PTR(btf, "init_btf")) + break; + id = btf__add_struct(btf, "foo", 20); + if (!ASSERT_EQ(id, 5, "btf__add_struct foo")) + break; + err = btf__add_field(btf, "a", LIST_HEAD, 0, 0); + if (!ASSERT_OK(err, "btf__add_field foo::a")) + break; + err = btf__add_field(btf, "b", SPIN_LOCK, 128, 0); + if (!ASSERT_OK(err, "btf__add_field foo::b")) + break; + id = btf__add_decl_tag(btf, "contains:bar:b", 5, 0); + if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:bar:b")) + break; + id = btf__add_struct(btf, "bar", 36); + if (!ASSERT_EQ(id, 7, "btf__add_struct bar")) + break; + err = btf__add_field(btf, "a", LIST_HEAD, 0, 0); + if (!ASSERT_OK(err, "btf__add_field bar::a")) + break; + err = btf__add_field(btf, "b", LIST_NODE, 128, 0); + if (!ASSERT_OK(err, "btf__add_field bar::b")) + break; + err = btf__add_field(btf, "c", SPIN_LOCK, 256, 0); + if (!ASSERT_OK(err, "btf__add_field bar::c")) + break; + id = btf__add_decl_tag(btf, "contains:baz:a", 7, 0); + if (!ASSERT_EQ(id, 8, "btf__add_decl_tag contains:baz:a")) + break; + id = btf__add_struct(btf, "baz", 16); + if (!ASSERT_EQ(id, 9, "btf__add_struct baz")) + break; + err = btf__add_field(btf, "a", LIST_NODE, 0, 0); + if (!ASSERT_OK(err, "btf__add_field baz:a")) + break; + + err = btf__load_into_kernel(btf); + ASSERT_EQ(err, 0, "check btf"); + btf__free(btf); + break; + } + + while (test__start_subtest("btf: owning | owned -> owning | owned -> owned")) { + btf = init_btf(); + if (!ASSERT_OK_PTR(btf, "init_btf")) + break; + id = btf__add_struct(btf, "foo", 36); + if (!ASSERT_EQ(id, 5, "btf__add_struct foo")) + break; + err = btf__add_field(btf, "a", LIST_HEAD, 0, 0); + if (!ASSERT_OK(err, "btf__add_field foo::a")) + break; + err = btf__add_field(btf, "b", LIST_NODE, 128, 0); + if (!ASSERT_OK(err, "btf__add_field foo::b")) + break; + err = btf__add_field(btf, "c", SPIN_LOCK, 256, 0); + if (!ASSERT_OK(err, "btf__add_field foo::c")) + break; + id = btf__add_decl_tag(btf, "contains:bar:b", 5, 0); + if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:bar:b")) + break; + id = btf__add_struct(btf, "bar", 36); + if (!ASSERT_EQ(id, 7, "btf__add_struct bar")) + break; + err = btf__add_field(btf, "a", LIST_HEAD, 0, 0); + if (!ASSERT_OK(err, "btf__add_field bar:a")) + break; + err = btf__add_field(btf, "b", LIST_NODE, 128, 0); + if (!ASSERT_OK(err, "btf__add_field bar:b")) + break; + err = btf__add_field(btf, "c", SPIN_LOCK, 256, 0); + if (!ASSERT_OK(err, "btf__add_field bar:c")) + break; + id = btf__add_decl_tag(btf, "contains:baz:a", 7, 0); + if (!ASSERT_EQ(id, 8, "btf__add_decl_tag contains:baz:a")) + break; + id = btf__add_struct(btf, "baz", 16); + if (!ASSERT_EQ(id, 9, "btf__add_struct baz")) + break; + err = btf__add_field(btf, "a", LIST_NODE, 0, 0); + if (!ASSERT_OK(err, "btf__add_field baz:a")) + break; + + err = btf__load_into_kernel(btf); + ASSERT_EQ(err, -ELOOP, "check btf"); + btf__free(btf); + break; + } + + while (test__start_subtest("btf: owning -> owning | owned -> owning | owned -> owned")) { + btf = init_btf(); + if (!ASSERT_OK_PTR(btf, "init_btf")) + break; + id = btf__add_struct(btf, "foo", 20); + if (!ASSERT_EQ(id, 5, "btf__add_struct foo")) + break; + err = btf__add_field(btf, "a", LIST_HEAD, 0, 0); + if (!ASSERT_OK(err, "btf__add_field foo::a")) + break; + err = btf__add_field(btf, "b", SPIN_LOCK, 128, 0); + if (!ASSERT_OK(err, "btf__add_field foo::b")) + break; + id = btf__add_decl_tag(btf, "contains:bar:b", 5, 0); + if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:bar:b")) + break; + id = btf__add_struct(btf, "bar", 36); + if (!ASSERT_EQ(id, 7, "btf__add_struct bar")) + break; + err = btf__add_field(btf, "a", LIST_HEAD, 0, 0); + if (!ASSERT_OK(err, "btf__add_field bar::a")) + break; + err = btf__add_field(btf, "b", LIST_NODE, 128, 0); + if (!ASSERT_OK(err, "btf__add_field bar::b")) + break; + err = btf__add_field(btf, "c", SPIN_LOCK, 256, 0); + if (!ASSERT_OK(err, "btf__add_field bar::c")) + break; + id = btf__add_decl_tag(btf, "contains:baz:b", 7, 0); + if (!ASSERT_EQ(id, 8, "btf__add_decl_tag")) + break; + id = btf__add_struct(btf, "baz", 36); + if (!ASSERT_EQ(id, 9, "btf__add_struct baz")) + break; + err = btf__add_field(btf, "a", LIST_HEAD, 0, 0); + if (!ASSERT_OK(err, "btf__add_field bar::a")) + break; + err = btf__add_field(btf, "b", LIST_NODE, 128, 0); + if (!ASSERT_OK(err, "btf__add_field bar::b")) + break; + err = btf__add_field(btf, "c", SPIN_LOCK, 256, 0); + if (!ASSERT_OK(err, "btf__add_field bar::c")) + break; + id = btf__add_decl_tag(btf, "contains:bam:a", 9, 0); + if (!ASSERT_EQ(id, 10, "btf__add_decl_tag contains:bam:a")) + break; + id = btf__add_struct(btf, "bam", 16); + if (!ASSERT_EQ(id, 11, "btf__add_struct bam")) + break; + err = btf__add_field(btf, "a", LIST_NODE, 0, 0); + if (!ASSERT_OK(err, "btf__add_field bam::a")) + break; + + err = btf__load_into_kernel(btf); + ASSERT_EQ(err, -ELOOP, "check btf"); + btf__free(btf); + break; + } +} + void test_linked_list(void) { int i; @@ -245,6 +729,7 @@ void test_linked_list(void) test_linked_list_fail_prog(linked_list_fail_tests[i].prog_name, linked_list_fail_tests[i].err_msg); } + test_btf(); test_linked_list_success(PUSH_POP, false); test_linked_list_success(PUSH_POP, true); test_linked_list_success(PUSH_POP_MULT, false); From 0a2f85a1be4328d29aefa54684d10c23a3298fef Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 18 Nov 2022 07:26:14 +0530 Subject: [PATCH 049/101] selftests/bpf: Temporarily disable linked list tests The latest clang nightly as of writing crashes with the given test case for BPF linked lists wherever global glock, ghead, glock2 are used, hence comment out the parts that cause the crash, and prepare this commit so that it can be reverted when the fix has been made. More context in [0]. [0]: https://lore.kernel.org/bpf/d56223f9-483e-fbc1-4564-44c0858a1e3e@meta.com Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118015614.2013203-25-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/prog_tests/linked_list.c | 21 ++++++++++++------- .../testing/selftests/bpf/progs/linked_list.c | 11 +++++++++- .../testing/selftests/bpf/progs/linked_list.h | 2 ++ .../selftests/bpf/progs/linked_list_fail.c | 16 +++++++------- 4 files changed, 34 insertions(+), 16 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/linked_list.c b/tools/testing/selftests/bpf/prog_tests/linked_list.c index dd73d0a62c6e..6170d36fe5fc 100644 --- a/tools/testing/selftests/bpf/prog_tests/linked_list.c +++ b/tools/testing/selftests/bpf/prog_tests/linked_list.c @@ -24,7 +24,9 @@ static struct { { #test "_missing_lock_pop_back", \ "bpf_spin_lock at off=" #off " must be held for bpf_list_head" }, TEST(kptr, 32) +/* FIXME TEST(global, 16) +*/ TEST(map, 0) TEST(inner_map, 0) #undef TEST @@ -32,9 +34,6 @@ static struct { { #test "_kptr_incorrect_lock_" #op, \ "held lock and object are not in the same allocation\n" \ "bpf_spin_lock at off=32 must be held for bpf_list_head" }, \ - { #test "_global_incorrect_lock_" #op, \ - "held lock and object are not in the same allocation\n" \ - "bpf_spin_lock at off=16 must be held for bpf_list_head" }, \ { #test "_map_incorrect_lock_" #op, \ "held lock and object are not in the same allocation\n" \ "bpf_spin_lock at off=0 must be held for bpf_list_head" }, \ @@ -45,10 +44,6 @@ static struct { TEST(kptr, push_back) TEST(kptr, pop_front) TEST(kptr, pop_back) - TEST(global, push_front) - TEST(global, push_back) - TEST(global, pop_front) - TEST(global, pop_back) TEST(map, push_front) TEST(map, push_back) TEST(map, pop_front) @@ -58,12 +53,14 @@ static struct { TEST(inner_map, pop_front) TEST(inner_map, pop_back) #undef TEST +/* FIXME { "map_compat_kprobe", "tracing progs cannot use bpf_list_head yet" }, { "map_compat_kretprobe", "tracing progs cannot use bpf_list_head yet" }, { "map_compat_tp", "tracing progs cannot use bpf_list_head yet" }, { "map_compat_perf", "tracing progs cannot use bpf_list_head yet" }, { "map_compat_raw_tp", "tracing progs cannot use bpf_list_head yet" }, { "map_compat_raw_tp_w", "tracing progs cannot use bpf_list_head yet" }, +*/ { "obj_type_id_oor", "local type ID argument must be in range [0, U32_MAX]" }, { "obj_new_no_composite", "bpf_obj_new type ID argument must be of a struct" }, { "obj_new_no_struct", "bpf_obj_new type ID argument must be of a struct" }, @@ -78,6 +75,7 @@ static struct { { "direct_write_head", "direct access to bpf_list_head is disallowed" }, { "direct_read_node", "direct access to bpf_list_node is disallowed" }, { "direct_write_node", "direct access to bpf_list_node is disallowed" }, +/* FIXME { "write_after_push_front", "only read is supported" }, { "write_after_push_back", "only read is supported" }, { "use_after_unlock_push_front", "invalid mem access 'scalar'" }, @@ -94,8 +92,11 @@ static struct { { "no_head_type", "bpf_list_head not found at offset=0" }, { "incorrect_head_var_off1", "R1 doesn't have constant offset" }, { "incorrect_head_var_off2", "variable ptr_ access var_off=(0x0; 0xffffffff) disallowed" }, +*/ { "incorrect_head_off1", "bpf_list_head not found at offset=17" }, +/* FIXME { "incorrect_head_off2", "bpf_list_head not found at offset=1" }, +*/ { "pop_front_off", "15: (bf) r1 = r6 ; R1_w=ptr_or_null_foo(id=4,ref_obj_id=4,off=40,imm=0) " "R6_w=ptr_or_null_foo(id=4,ref_obj_id=4,off=40,imm=0) refs=2,4\n" @@ -188,8 +189,10 @@ static void test_linked_list_success(int mode, bool leave_in_map) ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.global_list_push_pop), &opts); ASSERT_OK(ret, "global_list_push_pop"); ASSERT_OK(opts.retval, "global_list_push_pop retval"); + /* FIXME: if (!leave_in_map) clear_fields(skel->maps.data_A); + */ if (mode == PUSH_POP) goto end; @@ -210,8 +213,10 @@ ppm: ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.global_list_push_pop_multiple), &opts); ASSERT_OK(ret, "global_list_push_pop_multiple"); ASSERT_OK(opts.retval, "global_list_push_pop_multiple retval"); + /* FIXME: if (!leave_in_map) clear_fields(skel->maps.data_A); + */ if (mode == PUSH_POP_MULT) goto end; @@ -232,8 +237,10 @@ lil: ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.global_list_in_list), &opts); ASSERT_OK(ret, "global_list_in_list"); ASSERT_OK(opts.retval, "global_list_in_list retval"); + /* FIXME: if (!leave_in_map) clear_fields(skel->maps.data_A); + */ end: linked_list__destroy(skel); } diff --git a/tools/testing/selftests/bpf/progs/linked_list.c b/tools/testing/selftests/bpf/progs/linked_list.c index 2c7b615c6d41..a99103c86e48 100644 --- a/tools/testing/selftests/bpf/progs/linked_list.c +++ b/tools/testing/selftests/bpf/progs/linked_list.c @@ -291,7 +291,10 @@ int inner_map_list_push_pop(void *ctx) SEC("tc") int global_list_push_pop(void *ctx) { - return test_list_push_pop(&glock, &ghead); + /* FIXME: + * return test_list_push_pop(&glock, &ghead); + */ + return 0; } SEC("tc") @@ -327,10 +330,13 @@ int global_list_push_pop_multiple(void *ctx) { int ret; + /* FIXME: ret = list_push_pop_multiple(&glock, &ghead, false); if (ret) return ret; return list_push_pop_multiple(&glock, &ghead, true); + */ + return 0; } SEC("tc") @@ -364,7 +370,10 @@ int inner_map_list_in_list(void *ctx) SEC("tc") int global_list_in_list(void *ctx) { + /* FIXME return test_list_in_list(&glock, &ghead); + */ + return 0; } char _license[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/progs/linked_list.h b/tools/testing/selftests/bpf/progs/linked_list.h index 8db80ed64db1..93157efc2d04 100644 --- a/tools/testing/selftests/bpf/progs/linked_list.h +++ b/tools/testing/selftests/bpf/progs/linked_list.h @@ -47,10 +47,12 @@ struct { }, }; +/* FIXME #define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8))) private(A) struct bpf_spin_lock glock; private(A) struct bpf_list_head ghead __contains(foo, node); private(B) struct bpf_spin_lock glock2; +*/ #endif diff --git a/tools/testing/selftests/bpf/progs/linked_list_fail.c b/tools/testing/selftests/bpf/progs/linked_list_fail.c index 1d9017240e19..1b7ed1d3a9bb 100644 --- a/tools/testing/selftests/bpf/progs/linked_list_fail.c +++ b/tools/testing/selftests/bpf/progs/linked_list_fail.c @@ -59,10 +59,12 @@ CHECK(kptr, push_back, &f->head); CHECK(kptr, pop_front, &f->head); CHECK(kptr, pop_back, &f->head); +/* FIXME CHECK(global, push_front, &ghead); CHECK(global, push_back, &ghead); CHECK(global, pop_front, &ghead); CHECK(global, pop_back, &ghead); +*/ CHECK(map, push_front, &v->head); CHECK(map, push_back, &v->head); @@ -89,23 +91,15 @@ CHECK(inner_map, pop_back, &iv->head); #define CHECK_OP(op) \ CHECK(kptr_kptr, op, &f1->lock, &f2->head); \ - CHECK(kptr_global, op, &f1->lock, &ghead); \ CHECK(kptr_map, op, &f1->lock, &v->head); \ CHECK(kptr_inner_map, op, &f1->lock, &iv->head); \ \ - CHECK(global_global, op, &glock2, &ghead); \ - CHECK(global_kptr, op, &glock, &f1->head); \ - CHECK(global_map, op, &glock, &v->head); \ - CHECK(global_inner_map, op, &glock, &iv->head); \ - \ CHECK(map_map, op, &v->lock, &v2->head); \ CHECK(map_kptr, op, &v->lock, &f2->head); \ - CHECK(map_global, op, &v->lock, &ghead); \ CHECK(map_inner_map, op, &v->lock, &iv->head); \ \ CHECK(inner_map_inner_map, op, &iv->lock, &iv2->head); \ CHECK(inner_map_kptr, op, &iv->lock, &f2->head); \ - CHECK(inner_map_global, op, &iv->lock, &ghead); \ CHECK(inner_map_map, op, &iv->lock, &v->head); CHECK_OP(push_front); @@ -117,6 +111,7 @@ CHECK_OP(pop_back); #undef CHECK_OP #undef INIT +/* FIXME SEC("?kprobe/xyz") int map_compat_kprobe(void *ctx) { @@ -158,6 +153,7 @@ int map_compat_raw_tp_w(void *ctx) bpf_list_push_front(&ghead, NULL); return 0; } +*/ SEC("?tc") int obj_type_id_oor(void *ctx) @@ -303,6 +299,7 @@ int direct_write_node(void *ctx) return 0; } +/* FIXME static __always_inline int write_after_op(void (*push_op)(void *head, void *node)) { @@ -506,6 +503,7 @@ int incorrect_head_var_off2(struct __sk_buff *ctx) return 0; } +*/ SEC("?tc") int incorrect_head_off1(void *ctx) @@ -529,6 +527,7 @@ int incorrect_head_off1(void *ctx) return 0; } +/* FIXME SEC("?tc") int incorrect_head_off2(void *ctx) { @@ -545,6 +544,7 @@ int incorrect_head_off2(void *ctx) return 0; } +*/ static __always_inline int pop_ptr_off(void *(*op)(void *head)) From 97c11d6e31547183e2404087f0fb23b34dbe2cc3 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Sat, 19 Nov 2022 00:29:38 +0530 Subject: [PATCH 050/101] selftests/bpf: Skip spin lock failure test on s390x Instead of adding the whole test to DENYLIST.s390x, which also has success test cases that should be run, just skip over failure test cases in case the JIT does not support kfuncs. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221118185938.2139616-3-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/prog_tests/spin_lock.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/spin_lock.c b/tools/testing/selftests/bpf/prog_tests/spin_lock.c index 72282e92a78a..d9270bd3d920 100644 --- a/tools/testing/selftests/bpf/prog_tests/spin_lock.c +++ b/tools/testing/selftests/bpf/prog_tests/spin_lock.c @@ -68,6 +68,12 @@ static void test_spin_lock_fail_prog(const char *prog_name, const char *err_msg) if (!ASSERT_ERR(ret, "test_spin_lock_fail__load must fail")) goto end; + /* Skip check if JIT does not support kfuncs */ + if (strstr(log_buf, "JIT does not support calling kernel function")) { + test__skip(); + goto end; + } + if (!ASSERT_OK_PTR(strstr(log_buf, err_msg), "expected error message")) { fprintf(stderr, "Expected: %s\n", err_msg); fprintf(stderr, "Verifier: %s\n", log_buf); From f80e16b614f303b520465b7c704ff89fab800f2f Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 17 Nov 2022 11:28:24 -0800 Subject: [PATCH 051/101] libbpf: Ignore hashmap__find() result explicitly in btf_dump Coverity is reporting that btf_dump_name_dups() doesn't check return result of hashmap__find() call. This is intentional, so make it explicit with (void) cast. Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20221117192824.4093553-1-andrii@kernel.org --- tools/lib/bpf/btf_dump.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index e9f849d82124..deb2bc9a0a7b 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -1543,7 +1543,7 @@ static size_t btf_dump_name_dups(struct btf_dump *d, struct hashmap *name_map, if (!new_name) return 1; - hashmap__find(name_map, orig_name, &dup_cnt); + (void)hashmap__find(name_map, orig_name, &dup_cnt); dup_cnt++; err = hashmap__set(name_map, new_name, dup_cnt, &old_name, NULL); From d1e91173cd29ba13c5953d1820a7543140feec93 Mon Sep 17 00:00:00 2001 From: Maryam Tahhan Date: Tue, 15 Nov 2022 09:49:21 -0500 Subject: [PATCH 052/101] bpf, docs: DEVMAPs and XDP_REDIRECT MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add documentation for BPF_MAP_TYPE_DEVMAP and BPF_MAP_TYPE_DEVMAP_HASH including kernel version introduced, usage and examples. Add documentation that describes XDP_REDIRECT. Signed-off-by: Maryam Tahhan Signed-off-by: Daniel Borkmann Reviewed-by: Toke Høiland-Jørgensen Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20221115144921.165483-1-mtahhan@redhat.com --- Documentation/bpf/index.rst | 1 + Documentation/bpf/map_devmap.rst | 222 +++++++++++++++++++++++++++++++ Documentation/bpf/redirect.rst | 81 +++++++++++ net/core/filter.c | 8 +- 4 files changed, 310 insertions(+), 2 deletions(-) create mode 100644 Documentation/bpf/map_devmap.rst create mode 100644 Documentation/bpf/redirect.rst diff --git a/Documentation/bpf/index.rst b/Documentation/bpf/index.rst index 1b50de1983ee..1088d44634d6 100644 --- a/Documentation/bpf/index.rst +++ b/Documentation/bpf/index.rst @@ -29,6 +29,7 @@ that goes into great technical depth about the BPF Architecture. clang-notes linux-notes other + redirect .. only:: subproject and html diff --git a/Documentation/bpf/map_devmap.rst b/Documentation/bpf/map_devmap.rst new file mode 100644 index 000000000000..f64da348dbfe --- /dev/null +++ b/Documentation/bpf/map_devmap.rst @@ -0,0 +1,222 @@ +.. SPDX-License-Identifier: GPL-2.0-only +.. Copyright (C) 2022 Red Hat, Inc. + +================================================= +BPF_MAP_TYPE_DEVMAP and BPF_MAP_TYPE_DEVMAP_HASH +================================================= + +.. note:: + - ``BPF_MAP_TYPE_DEVMAP`` was introduced in kernel version 4.14 + - ``BPF_MAP_TYPE_DEVMAP_HASH`` was introduced in kernel version 5.4 + +``BPF_MAP_TYPE_DEVMAP`` and ``BPF_MAP_TYPE_DEVMAP_HASH`` are BPF maps primarily +used as backend maps for the XDP BPF helper call ``bpf_redirect_map()``. +``BPF_MAP_TYPE_DEVMAP`` is backed by an array that uses the key as +the index to lookup a reference to a net device. While ``BPF_MAP_TYPE_DEVMAP_HASH`` +is backed by a hash table that uses a key to lookup a reference to a net device. +The user provides either <``key``/ ``ifindex``> or <``key``/ ``struct bpf_devmap_val``> +pairs to update the maps with new net devices. + +.. note:: + - The key to a hash map doesn't have to be an ``ifindex``. + - While ``BPF_MAP_TYPE_DEVMAP_HASH`` allows for densely packing the net devices + it comes at the cost of a hash of the key when performing a look up. + +The setup and packet enqueue/send code is shared between the two types of +devmap; only the lookup and insertion is different. + +Usage +===== +Kernel BPF +---------- +.. c:function:: + long bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags) + +Redirect the packet to the endpoint referenced by ``map`` at index ``key``. +For ``BPF_MAP_TYPE_DEVMAP`` and ``BPF_MAP_TYPE_DEVMAP_HASH`` this map contains +references to net devices (for forwarding packets through other ports). + +The lower two bits of *flags* are used as the return code if the map lookup +fails. This is so that the return value can be one of the XDP program return +codes up to ``XDP_TX``, as chosen by the caller. The higher bits of ``flags`` +can be set to ``BPF_F_BROADCAST`` or ``BPF_F_EXCLUDE_INGRESS`` as defined +below. + +With ``BPF_F_BROADCAST`` the packet will be broadcast to all the interfaces +in the map, with ``BPF_F_EXCLUDE_INGRESS`` the ingress interface will be excluded +from the broadcast. + +.. note:: + - The key is ignored if BPF_F_BROADCAST is set. + - The broadcast feature can also be used to implement multicast forwarding: + simply create multiple DEVMAPs, each one corresponding to a single multicast group. + +This helper will return ``XDP_REDIRECT`` on success, or the value of the two +lower bits of the ``flags`` argument if the map lookup fails. + +More information about redirection can be found :doc:`redirect` + +.. c:function:: + void *bpf_map_lookup_elem(struct bpf_map *map, const void *key) + +Net device entries can be retrieved using the ``bpf_map_lookup_elem()`` +helper. + +Userspace +--------- +.. note:: + DEVMAP entries can only be updated/deleted from user space and not + from an eBPF program. Trying to call these functions from a kernel eBPF + program will result in the program failing to load and a verifier warning. + +.. c:function:: + int bpf_map_update_elem(int fd, const void *key, const void *value, __u64 flags); + + Net device entries can be added or updated using the ``bpf_map_update_elem()`` + helper. This helper replaces existing elements atomically. The ``value`` parameter + can be ``struct bpf_devmap_val`` or a simple ``int ifindex`` for backwards + compatibility. + + .. code-block:: c + + struct bpf_devmap_val { + __u32 ifindex; /* device index */ + union { + int fd; /* prog fd on map write */ + __u32 id; /* prog id on map read */ + } bpf_prog; + }; + + The ``flags`` argument can be one of the following: + + - ``BPF_ANY``: Create a new element or update an existing element. + - ``BPF_NOEXIST``: Create a new element only if it did not exist. + - ``BPF_EXIST``: Update an existing element. + + DEVMAPs can associate a program with a device entry by adding a ``bpf_prog.fd`` + to ``struct bpf_devmap_val``. Programs are run after ``XDP_REDIRECT`` and have + access to both Rx device and Tx device. The program associated with the ``fd`` + must have type XDP with expected attach type ``xdp_devmap``. + When a program is associated with a device index, the program is run on an + ``XDP_REDIRECT`` and before the buffer is added to the per-cpu queue. Examples + of how to attach/use xdp_devmap progs can be found in the kernel selftests: + + - ``tools/testing/selftests/bpf/prog_tests/xdp_devmap_attach.c`` + - ``tools/testing/selftests/bpf/progs/test_xdp_with_devmap_helpers.c`` + +.. c:function:: + int bpf_map_lookup_elem(int fd, const void *key, void *value); + + Net device entries can be retrieved using the ``bpf_map_lookup_elem()`` + helper. + +.. c:function:: + int bpf_map_delete_elem(int fd, const void *key); + + Net device entries can be deleted using the ``bpf_map_delete_elem()`` + helper. This helper will return 0 on success, or negative error in case of + failure. + +Examples +======== + +Kernel BPF +---------- + +The following code snippet shows how to declare a ``BPF_MAP_TYPE_DEVMAP`` +called tx_port. + +.. code-block:: c + + struct { + __uint(type, BPF_MAP_TYPE_DEVMAP); + __type(key, __u32); + __type(value, __u32); + __uint(max_entries, 256); + } tx_port SEC(".maps"); + +The following code snippet shows how to declare a ``BPF_MAP_TYPE_DEVMAP_HASH`` +called forward_map. + +.. code-block:: c + + struct { + __uint(type, BPF_MAP_TYPE_DEVMAP_HASH); + __type(key, __u32); + __type(value, struct bpf_devmap_val); + __uint(max_entries, 32); + } forward_map SEC(".maps"); + +.. note:: + + The value type in the DEVMAP above is a ``struct bpf_devmap_val`` + +The following code snippet shows a simple xdp_redirect_map program. This program +would work with a user space program that populates the devmap ``forward_map`` based +on ingress ifindexes. The BPF program (below) is redirecting packets using the +ingress ``ifindex`` as the ``key``. + +.. code-block:: c + + SEC("xdp") + int xdp_redirect_map_func(struct xdp_md *ctx) + { + int index = ctx->ingress_ifindex; + + return bpf_redirect_map(&forward_map, index, 0); + } + +The following code snippet shows a BPF program that is broadcasting packets to +all the interfaces in the ``tx_port`` devmap. + +.. code-block:: c + + SEC("xdp") + int xdp_redirect_map_func(struct xdp_md *ctx) + { + return bpf_redirect_map(&tx_port, 0, BPF_F_BROADCAST | BPF_F_EXCLUDE_INGRESS); + } + +User space +---------- + +The following code snippet shows how to update a devmap called ``tx_port``. + +.. code-block:: c + + int update_devmap(int ifindex, int redirect_ifindex) + { + int ret; + + ret = bpf_map_update_elem(bpf_map__fd(tx_port), &ifindex, &redirect_ifindex, 0); + if (ret < 0) { + fprintf(stderr, "Failed to update devmap_ value: %s\n", + strerror(errno)); + } + + return ret; + } + +The following code snippet shows how to update a hash_devmap called ``forward_map``. + +.. code-block:: c + + int update_devmap(int ifindex, int redirect_ifindex) + { + struct bpf_devmap_val devmap_val = { .ifindex = redirect_ifindex }; + int ret; + + ret = bpf_map_update_elem(bpf_map__fd(forward_map), &ifindex, &devmap_val, 0); + if (ret < 0) { + fprintf(stderr, "Failed to update devmap_ value: %s\n", + strerror(errno)); + } + return ret; + } + +References +=========== + +- https://lwn.net/Articles/728146/ +- https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/commit/?id=6f9d451ab1a33728adb72d7ff66a7b374d665176 +- https://elixir.bootlin.com/linux/latest/source/net/core/filter.c#L4106 diff --git a/Documentation/bpf/redirect.rst b/Documentation/bpf/redirect.rst new file mode 100644 index 000000000000..2fa2b0b05004 --- /dev/null +++ b/Documentation/bpf/redirect.rst @@ -0,0 +1,81 @@ +.. SPDX-License-Identifier: GPL-2.0-only +.. Copyright (C) 2022 Red Hat, Inc. + +======== +Redirect +======== +XDP_REDIRECT +############ +Supported maps +-------------- + +XDP_REDIRECT works with the following map types: + +- ``BPF_MAP_TYPE_DEVMAP`` +- ``BPF_MAP_TYPE_DEVMAP_HASH`` +- ``BPF_MAP_TYPE_CPUMAP`` +- ``BPF_MAP_TYPE_XSKMAP`` + +For more information on these maps, please see the specific map documentation. + +Process +------- + +.. kernel-doc:: net/core/filter.c + :doc: xdp redirect + +.. note:: + Not all drivers support transmitting frames after a redirect, and for + those that do, not all of them support non-linear frames. Non-linear xdp + bufs/frames are bufs/frames that contain more than one fragment. + +Debugging packet drops +---------------------- +Silent packet drops for XDP_REDIRECT can be debugged using: + +- bpf_trace +- perf_record + +bpf_trace +^^^^^^^^^ +The following bpftrace command can be used to capture and count all XDP tracepoints: + +.. code-block:: none + + sudo bpftrace -e 'tracepoint:xdp:* { @cnt[probe] = count(); }' + Attaching 12 probes... + ^C + + @cnt[tracepoint:xdp:mem_connect]: 18 + @cnt[tracepoint:xdp:mem_disconnect]: 18 + @cnt[tracepoint:xdp:xdp_exception]: 19605 + @cnt[tracepoint:xdp:xdp_devmap_xmit]: 1393604 + @cnt[tracepoint:xdp:xdp_redirect]: 22292200 + +.. note:: + The various xdp tracepoints can be found in ``source/include/trace/events/xdp.h`` + +The following bpftrace command can be used to extract the ``ERRNO`` being returned as +part of the err parameter: + +.. code-block:: none + + sudo bpftrace -e \ + 'tracepoint:xdp:xdp_redirect*_err {@redir_errno[-args->err] = count();} + tracepoint:xdp:xdp_devmap_xmit {@devmap_errno[-args->err] = count();}' + +perf record +^^^^^^^^^^^ +The perf tool also supports recording tracepoints: + +.. code-block:: none + + perf record -a -e xdp:xdp_redirect_err \ + -e xdp:xdp_redirect_map_err \ + -e xdp:xdp_exception \ + -e xdp:xdp_devmap_xmit + +References +=========== + +- https://github.com/xdp-project/xdp-tutorial/tree/master/tracing02-xdp-monitor diff --git a/net/core/filter.c b/net/core/filter.c index 754dd01354d8..2a105fb1ceb2 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -4108,7 +4108,10 @@ static const struct bpf_func_proto bpf_xdp_adjust_meta_proto = { .arg2_type = ARG_ANYTHING, }; -/* XDP_REDIRECT works by a three-step process, implemented in the functions +/** + * DOC: xdp redirect + * + * XDP_REDIRECT works by a three-step process, implemented in the functions * below: * * 1. The bpf_redirect() and bpf_redirect_map() helpers will lookup the target @@ -4123,7 +4126,8 @@ static const struct bpf_func_proto bpf_xdp_adjust_meta_proto = { * 3. Before exiting its NAPI poll loop, the driver will call xdp_do_flush(), * which will flush all the different bulk queues, thus completing the * redirect. - * + */ +/* * Pointers to the map entries will be kept around for this whole sequence of * steps, protected by RCU. However, there is no top-level rcu_read_lock() in * the core code; instead, the RCU protection relies on everything happening From ee748cd95e3adf4acdb05194b2ea68e4073e09b6 Mon Sep 17 00:00:00 2001 From: Tiezhu Yang Date: Fri, 18 Nov 2022 17:50:01 +0800 Subject: [PATCH 053/101] bpf, samples: Use "grep -E" instead of "egrep" The latest version of grep (3.8+) claims the egrep is now obsolete so the build now contains warnings that look like: egrep: warning: egrep is obsolescent; using grep -E Fix this up by moving the related file to use "grep -E" instead. Signed-off-by: Tiezhu Yang Signed-off-by: Daniel Borkmann Acked-by: Jiri Olsa Link: https://lore.kernel.org/bpf/1668765001-12477-1-git-send-email-yangtiezhu@loongson.cn --- samples/bpf/test_cgrp2_tc.sh | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/samples/bpf/test_cgrp2_tc.sh b/samples/bpf/test_cgrp2_tc.sh index 12faf5847e22..395573be6ae8 100755 --- a/samples/bpf/test_cgrp2_tc.sh +++ b/samples/bpf/test_cgrp2_tc.sh @@ -115,7 +115,7 @@ do_exit() { if [ "$DEBUG" == "yes" ] && [ "$MODE" != 'cleanuponly' ] then echo "------ DEBUG ------" - echo "mount: "; mount | egrep '(cgroup2|bpf)'; echo + echo "mount: "; mount | grep -E '(cgroup2|bpf)'; echo echo "$CGRP2_TC_LEAF: "; ls -l $CGRP2_TC_LEAF; echo if [ -d "$BPF_FS_TC_SHARE" ] then From ef66c5475d7fb864c2418d3bdd19dee46324624b Mon Sep 17 00:00:00 2001 From: David Vernet Date: Sat, 19 Nov 2022 23:10:01 -0600 Subject: [PATCH 054/101] bpf: Allow multiple modifiers in reg_type_str() prefix reg_type_str() in the verifier currently only allows a single register type modifier to be present in the 'prefix' string which is eventually stored in the env type_str_buf. This currently works fine because there are no overlapping type modifiers, but once PTR_TRUSTED is added, that will no longer be the case. This patch updates reg_type_str() to support having multiple modifiers in the prefix string, and updates the size of type_str_buf to be 128 bytes. Signed-off-by: David Vernet Link: https://lore.kernel.org/r/20221120051004.3605026-2-void@manifault.com Signed-off-by: Alexei Starovoitov --- include/linux/bpf_verifier.h | 2 +- kernel/bpf/verifier.c | 19 ++++++++----------- 2 files changed, 9 insertions(+), 12 deletions(-) diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 23f30c685f28..608dde740fef 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -19,7 +19,7 @@ */ #define BPF_MAX_VAR_SIZ (1 << 29) /* size of type_str_buf in bpf_verifier. */ -#define TYPE_STR_BUF_LEN 64 +#define TYPE_STR_BUF_LEN 128 /* Liveness marks, used for registers and spilled-regs (in stack slots). * Read marks propagate upwards until they find a write mark; they record that diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 195d24316750..67a6f11d953c 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -557,7 +557,7 @@ static bool is_cmpxchg_insn(const struct bpf_insn *insn) static const char *reg_type_str(struct bpf_verifier_env *env, enum bpf_reg_type type) { - char postfix[16] = {0}, prefix[32] = {0}; + char postfix[16] = {0}, prefix[64] = {0}; static const char * const str[] = { [NOT_INIT] = "?", [SCALAR_VALUE] = "scalar", @@ -589,16 +589,13 @@ static const char *reg_type_str(struct bpf_verifier_env *env, strncpy(postfix, "_or_null", 16); } - if (type & MEM_RDONLY) - strncpy(prefix, "rdonly_", 32); - if (type & MEM_RINGBUF) - strncpy(prefix, "ringbuf_", 32); - if (type & MEM_USER) - strncpy(prefix, "user_", 32); - if (type & MEM_PERCPU) - strncpy(prefix, "percpu_", 32); - if (type & PTR_UNTRUSTED) - strncpy(prefix, "untrusted_", 32); + snprintf(prefix, sizeof(prefix), "%s%s%s%s%s", + type & MEM_RDONLY ? "rdonly_" : "", + type & MEM_RINGBUF ? "ringbuf_" : "", + type & MEM_USER ? "user_" : "", + type & MEM_PERCPU ? "percpu_" : "", + type & PTR_UNTRUSTED ? "untrusted_" : "" + ); snprintf(env->type_str_buf, TYPE_STR_BUF_LEN, "%s%s%s", prefix, str[base_type(type)], postfix); From 3f00c52393445ed49aadc1a567aa502c6333b1a1 Mon Sep 17 00:00:00 2001 From: David Vernet Date: Sat, 19 Nov 2022 23:10:02 -0600 Subject: [PATCH 055/101] bpf: Allow trusted pointers to be passed to KF_TRUSTED_ARGS kfuncs Kfuncs currently support specifying the KF_TRUSTED_ARGS flag to signal to the verifier that it should enforce that a BPF program passes it a "safe", trusted pointer. Currently, "safe" means that the pointer is either PTR_TO_CTX, or is refcounted. There may be cases, however, where the kernel passes a BPF program a safe / trusted pointer to an object that the BPF program wishes to use as a kptr, but because the object does not yet have a ref_obj_id from the perspective of the verifier, the program would be unable to pass it to a KF_ACQUIRE | KF_TRUSTED_ARGS kfunc. The solution is to expand the set of pointers that are considered trusted according to KF_TRUSTED_ARGS, so that programs can invoke kfuncs with these pointers without getting rejected by the verifier. There is already a PTR_UNTRUSTED flag that is set in some scenarios, such as when a BPF program reads a kptr directly from a map without performing a bpf_kptr_xchg() call. These pointers of course can and should be rejected by the verifier. Unfortunately, however, PTR_UNTRUSTED does not cover all the cases for safety that need to be addressed to adequately protect kfuncs. Specifically, pointers obtained by a BPF program "walking" a struct are _not_ considered PTR_UNTRUSTED according to BPF. For example, say that we were to add a kfunc called bpf_task_acquire(), with KF_ACQUIRE | KF_TRUSTED_ARGS, to acquire a struct task_struct *. If we only used PTR_UNTRUSTED to signal that a task was unsafe to pass to a kfunc, the verifier would mistakenly allow the following unsafe BPF program to be loaded: SEC("tp_btf/task_newtask") int BPF_PROG(unsafe_acquire_task, struct task_struct *task, u64 clone_flags) { struct task_struct *acquired, *nested; nested = task->last_wakee; /* Would not be rejected by the verifier. */ acquired = bpf_task_acquire(nested); if (!acquired) return 0; bpf_task_release(acquired); return 0; } To address this, this patch defines a new type flag called PTR_TRUSTED which tracks whether a PTR_TO_BTF_ID pointer is safe to pass to a KF_TRUSTED_ARGS kfunc or a BPF helper function. PTR_TRUSTED pointers are passed directly from the kernel as a tracepoint or struct_ops callback argument. Any nested pointer that is obtained from walking a PTR_TRUSTED pointer is no longer PTR_TRUSTED. From the example above, the struct task_struct *task argument is PTR_TRUSTED, but the 'nested' pointer obtained from 'task->last_wakee' is not PTR_TRUSTED. A subsequent patch will add kfuncs for storing a task kfunc as a kptr, and then another patch will add selftests to validate. Signed-off-by: David Vernet Link: https://lore.kernel.org/r/20221120051004.3605026-3-void@manifault.com Signed-off-by: Alexei Starovoitov --- Documentation/bpf/kfuncs.rst | 24 +++---- include/linux/bpf.h | 30 ++++++++ include/linux/bpf_verifier.h | 7 ++ include/linux/btf.h | 65 ++++++++++------- kernel/bpf/btf.c | 8 +++ kernel/bpf/verifier.c | 69 +++++++++++++++---- kernel/trace/bpf_trace.c | 2 +- net/ipv4/bpf_tcp_ca.c | 4 +- tools/testing/selftests/bpf/verifier/calls.c | 2 +- .../selftests/bpf/verifier/ref_tracking.c | 4 +- 10 files changed, 161 insertions(+), 54 deletions(-) diff --git a/Documentation/bpf/kfuncs.rst b/Documentation/bpf/kfuncs.rst index 3b1501c3b6cd..90774479ab7a 100644 --- a/Documentation/bpf/kfuncs.rst +++ b/Documentation/bpf/kfuncs.rst @@ -161,22 +161,20 @@ KF_ACQUIRE and KF_RET_NULL flags. -------------------------- The KF_TRUSTED_ARGS flag is used for kfuncs taking pointer arguments. It -indicates that the all pointer arguments will always have a guaranteed lifetime, -and pointers to kernel objects are always passed to helpers in their unmodified -form (as obtained from acquire kfuncs). +indicates that the all pointer arguments are valid, and that all pointers to +BTF objects have been passed in their unmodified form (that is, at a zero +offset, and without having been obtained from walking another pointer). -It can be used to enforce that a pointer to a refcounted object acquired from a -kfunc or BPF helper is passed as an argument to this kfunc without any -modifications (e.g. pointer arithmetic) such that it is trusted and points to -the original object. +There are two types of pointers to kernel objects which are considered "valid": -Meanwhile, it is also allowed pass pointers to normal memory to such kfuncs, -but those can have a non-zero offset. +1. Pointers which are passed as tracepoint or struct_ops callback arguments. +2. Pointers which were returned from a KF_ACQUIRE or KF_KPTR_GET kfunc. -This flag is often used for kfuncs that operate (change some property, perform -some operation) on an object that was obtained using an acquire kfunc. Such -kfuncs need an unchanged pointer to ensure the integrity of the operation being -performed on the expected object. +Pointers to non-BTF objects (e.g. scalar pointers) may also be passed to +KF_TRUSTED_ARGS kfuncs, and may have a non-zero offset. + +The definition of "valid" pointers is subject to change at any time, and has +absolutely no ABI stability guarantees. 2.4.6 KF_SLEEPABLE flag ----------------------- diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 8b32376ce746..c9eafa67f2a2 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -543,6 +543,35 @@ enum bpf_type_flag { */ MEM_ALLOC = BIT(11 + BPF_BASE_TYPE_BITS), + /* PTR was passed from the kernel in a trusted context, and may be + * passed to KF_TRUSTED_ARGS kfuncs or BPF helper functions. + * Confusingly, this is _not_ the opposite of PTR_UNTRUSTED above. + * PTR_UNTRUSTED refers to a kptr that was read directly from a map + * without invoking bpf_kptr_xchg(). What we really need to know is + * whether a pointer is safe to pass to a kfunc or BPF helper function. + * While PTR_UNTRUSTED pointers are unsafe to pass to kfuncs and BPF + * helpers, they do not cover all possible instances of unsafe + * pointers. For example, a pointer that was obtained from walking a + * struct will _not_ get the PTR_UNTRUSTED type modifier, despite the + * fact that it may be NULL, invalid, etc. This is due to backwards + * compatibility requirements, as this was the behavior that was first + * introduced when kptrs were added. The behavior is now considered + * deprecated, and PTR_UNTRUSTED will eventually be removed. + * + * PTR_TRUSTED, on the other hand, is a pointer that the kernel + * guarantees to be valid and safe to pass to kfuncs and BPF helpers. + * For example, pointers passed to tracepoint arguments are considered + * PTR_TRUSTED, as are pointers that are passed to struct_ops + * callbacks. As alluded to above, pointers that are obtained from + * walking PTR_TRUSTED pointers are _not_ trusted. For example, if a + * struct task_struct *task is PTR_TRUSTED, then accessing + * task->last_wakee will lose the PTR_TRUSTED modifier when it's stored + * in a BPF register. Similarly, pointers passed to certain programs + * types such as kretprobes are not guaranteed to be valid, as they may + * for example contain an object that was recently freed. + */ + PTR_TRUSTED = BIT(12 + BPF_BASE_TYPE_BITS), + __BPF_TYPE_FLAG_MAX, __BPF_TYPE_LAST_FLAG = __BPF_TYPE_FLAG_MAX - 1, }; @@ -636,6 +665,7 @@ enum bpf_return_type { RET_PTR_TO_RINGBUF_MEM_OR_NULL = PTR_MAYBE_NULL | MEM_RINGBUF | RET_PTR_TO_MEM, RET_PTR_TO_DYNPTR_MEM_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_MEM, RET_PTR_TO_BTF_ID_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_BTF_ID, + RET_PTR_TO_BTF_ID_TRUSTED = PTR_TRUSTED | RET_PTR_TO_BTF_ID, /* This must be the last entry. Its purpose is to ensure the enum is * wide enough to hold the higher bits reserved for bpf_type_flag. diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 608dde740fef..545152ac136c 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -680,4 +680,11 @@ static inline bool bpf_prog_check_recur(const struct bpf_prog *prog) } } +#define BPF_REG_TRUSTED_MODIFIERS (MEM_ALLOC | PTR_TRUSTED) + +static inline bool bpf_type_has_unsafe_modifiers(u32 type) +{ + return type_flag(type) & ~BPF_REG_TRUSTED_MODIFIERS; +} + #endif /* _LINUX_BPF_VERIFIER_H */ diff --git a/include/linux/btf.h b/include/linux/btf.h index d5b26380a60f..d38aa4251c28 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -19,36 +19,53 @@ #define KF_RELEASE (1 << 1) /* kfunc is a release function */ #define KF_RET_NULL (1 << 2) /* kfunc returns a pointer that may be NULL */ #define KF_KPTR_GET (1 << 3) /* kfunc returns reference to a kptr */ -/* Trusted arguments are those which are meant to be referenced arguments with - * unchanged offset. It is used to enforce that pointers obtained from acquire - * kfuncs remain unmodified when being passed to helpers taking trusted args. +/* Trusted arguments are those which are guaranteed to be valid when passed to + * the kfunc. It is used to enforce that pointers obtained from either acquire + * kfuncs, or from the main kernel on a tracepoint or struct_ops callback + * invocation, remain unmodified when being passed to helpers taking trusted + * args. * - * Consider - * struct foo { - * int data; - * struct foo *next; - * }; + * Consider, for example, the following new task tracepoint: * - * struct bar { - * int data; - * struct foo f; - * }; + * SEC("tp_btf/task_newtask") + * int BPF_PROG(new_task_tp, struct task_struct *task, u64 clone_flags) + * { + * ... + * } * - * struct foo *f = alloc_foo(); // Acquire kfunc - * struct bar *b = alloc_bar(); // Acquire kfunc + * And the following kfunc: * - * If a kfunc set_foo_data() wants to operate only on the allocated object, it - * will set the KF_TRUSTED_ARGS flag, which will prevent unsafe usage like: + * BTF_ID_FLAGS(func, bpf_task_acquire, KF_ACQUIRE | KF_TRUSTED_ARGS) * - * set_foo_data(f, 42); // Allowed - * set_foo_data(f->next, 42); // Rejected, non-referenced pointer - * set_foo_data(&f->next, 42);// Rejected, referenced, but wrong type - * set_foo_data(&b->f, 42); // Rejected, referenced, but bad offset + * All invocations to the kfunc must pass the unmodified, unwalked task: * - * In the final case, usually for the purposes of type matching, it is deduced - * by looking at the type of the member at the offset, but due to the - * requirement of trusted argument, this deduction will be strict and not done - * for this case. + * bpf_task_acquire(task); // Allowed + * bpf_task_acquire(task->last_wakee); // Rejected, walked task + * + * Programs may also pass referenced tasks directly to the kfunc: + * + * struct task_struct *acquired; + * + * acquired = bpf_task_acquire(task); // Allowed, same as above + * bpf_task_acquire(acquired); // Allowed + * bpf_task_acquire(task); // Allowed + * bpf_task_acquire(acquired->last_wakee); // Rejected, walked task + * + * Programs may _not_, however, pass a task from an arbitrary fentry/fexit, or + * kprobe/kretprobe to the kfunc, as BPF cannot guarantee that all of these + * pointers are guaranteed to be safe. For example, the following BPF program + * would be rejected: + * + * SEC("kretprobe/free_task") + * int BPF_PROG(free_task_probe, struct task_struct *tsk) + * { + * struct task_struct *acquired; + * + * acquired = bpf_task_acquire(acquired); // Rejected, not a trusted pointer + * bpf_task_release(acquired); + * + * return 0; + * } */ #define KF_TRUSTED_ARGS (1 << 4) /* kfunc only takes trusted pointer arguments */ #define KF_SLEEPABLE (1 << 5) /* kfunc may sleep */ diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index f7d5fab61535..d52054ec69c9 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -5799,6 +5799,11 @@ static u32 get_ctx_arg_idx(struct btf *btf, const struct btf_type *func_proto, return nr_args + 1; } +static bool prog_type_args_trusted(enum bpf_prog_type prog_type) +{ + return prog_type == BPF_PROG_TYPE_TRACING || prog_type == BPF_PROG_TYPE_STRUCT_OPS; +} + bool btf_ctx_access(int off, int size, enum bpf_access_type type, const struct bpf_prog *prog, struct bpf_insn_access_aux *info) @@ -5942,6 +5947,9 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, } info->reg_type = PTR_TO_BTF_ID; + if (prog_type_args_trusted(prog->type)) + info->reg_type |= PTR_TRUSTED; + if (tgt_prog) { enum bpf_prog_type tgt_type; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 67a6f11d953c..5bc9d84d7924 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -589,12 +589,13 @@ static const char *reg_type_str(struct bpf_verifier_env *env, strncpy(postfix, "_or_null", 16); } - snprintf(prefix, sizeof(prefix), "%s%s%s%s%s", + snprintf(prefix, sizeof(prefix), "%s%s%s%s%s%s", type & MEM_RDONLY ? "rdonly_" : "", type & MEM_RINGBUF ? "ringbuf_" : "", type & MEM_USER ? "user_" : "", type & MEM_PERCPU ? "percpu_" : "", - type & PTR_UNTRUSTED ? "untrusted_" : "" + type & PTR_UNTRUSTED ? "untrusted_" : "", + type & PTR_TRUSTED ? "trusted_" : "" ); snprintf(env->type_str_buf, TYPE_STR_BUF_LEN, "%s%s%s", @@ -3856,7 +3857,7 @@ static int map_kptr_match_type(struct bpf_verifier_env *env, struct bpf_reg_state *reg, u32 regno) { const char *targ_name = kernel_type_name(kptr_field->kptr.btf, kptr_field->kptr.btf_id); - int perm_flags = PTR_MAYBE_NULL; + int perm_flags = PTR_MAYBE_NULL | PTR_TRUSTED; const char *reg_name = ""; /* Only unreferenced case accepts untrusted pointers */ @@ -4732,6 +4733,9 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env, if (type_flag(reg->type) & PTR_UNTRUSTED) flag |= PTR_UNTRUSTED; + /* Any pointer obtained from walking a trusted pointer is no longer trusted. */ + flag &= ~PTR_TRUSTED; + if (atype == BPF_READ && value_regno >= 0) mark_btf_ld_reg(env, regs, value_regno, ret, reg->btf, btf_id, flag); @@ -5844,6 +5848,7 @@ static const struct bpf_reg_types btf_id_sock_common_types = { PTR_TO_TCP_SOCK, PTR_TO_XDP_SOCK, PTR_TO_BTF_ID, + PTR_TO_BTF_ID | PTR_TRUSTED, }, .btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON], }; @@ -5884,8 +5889,18 @@ static const struct bpf_reg_types scalar_types = { .types = { SCALAR_VALUE } }; static const struct bpf_reg_types context_types = { .types = { PTR_TO_CTX } }; static const struct bpf_reg_types ringbuf_mem_types = { .types = { PTR_TO_MEM | MEM_RINGBUF } }; static const struct bpf_reg_types const_map_ptr_types = { .types = { CONST_PTR_TO_MAP } }; -static const struct bpf_reg_types btf_ptr_types = { .types = { PTR_TO_BTF_ID } }; -static const struct bpf_reg_types percpu_btf_ptr_types = { .types = { PTR_TO_BTF_ID | MEM_PERCPU } }; +static const struct bpf_reg_types btf_ptr_types = { + .types = { + PTR_TO_BTF_ID, + PTR_TO_BTF_ID | PTR_TRUSTED, + }, +}; +static const struct bpf_reg_types percpu_btf_ptr_types = { + .types = { + PTR_TO_BTF_ID | MEM_PERCPU, + PTR_TO_BTF_ID | MEM_PERCPU | PTR_TRUSTED, + } +}; static const struct bpf_reg_types func_ptr_types = { .types = { PTR_TO_FUNC } }; static const struct bpf_reg_types stack_ptr_types = { .types = { PTR_TO_STACK } }; static const struct bpf_reg_types const_str_ptr_types = { .types = { PTR_TO_MAP_VALUE } }; @@ -5973,7 +5988,7 @@ static int check_reg_type(struct bpf_verifier_env *env, u32 regno, return -EACCES; found: - if (reg->type == PTR_TO_BTF_ID) { + if (reg->type == PTR_TO_BTF_ID || reg->type & PTR_TRUSTED) { /* For bpf_sk_release, it needs to match against first member * 'struct sock_common', hence make an exception for it. This * allows bpf_sk_release to work for multiple socket types. @@ -6055,6 +6070,8 @@ int check_func_arg_reg_off(struct bpf_verifier_env *env, */ case PTR_TO_BTF_ID: case PTR_TO_BTF_ID | MEM_ALLOC: + case PTR_TO_BTF_ID | PTR_TRUSTED: + case PTR_TO_BTF_ID | MEM_ALLOC | PTR_TRUSTED: /* When referenced PTR_TO_BTF_ID is passed to release function, * it's fixed offset must be 0. In the other cases, fixed offset * can be non-zero. @@ -7939,6 +7956,25 @@ static bool is_kfunc_arg_kptr_get(struct bpf_kfunc_call_arg_meta *meta, int arg) return arg == 0 && (meta->kfunc_flags & KF_KPTR_GET); } +static bool is_trusted_reg(const struct bpf_reg_state *reg) +{ + /* A referenced register is always trusted. */ + if (reg->ref_obj_id) + return true; + + /* If a register is not referenced, it is trusted if it has either the + * MEM_ALLOC or PTR_TRUSTED type modifiers, and no others. Some of the + * other type modifiers may be safe, but we elect to take an opt-in + * approach here as some (e.g. PTR_UNTRUSTED and PTR_MAYBE_NULL) are + * not. + * + * Eventually, we should make PTR_TRUSTED the single source of truth + * for whether a register is trusted. + */ + return type_flag(reg->type) & BPF_REG_TRUSTED_MODIFIERS && + !bpf_type_has_unsafe_modifiers(reg->type); +} + static bool __kfunc_param_match_suffix(const struct btf *btf, const struct btf_param *arg, const char *suffix) @@ -8220,7 +8256,7 @@ static int process_kf_arg_ptr_to_btf_id(struct bpf_verifier_env *env, const char *reg_ref_tname; u32 reg_ref_id; - if (reg->type == PTR_TO_BTF_ID) { + if (base_type(reg->type) == PTR_TO_BTF_ID) { reg_btf = reg->btf; reg_ref_id = reg->btf_id; } else { @@ -8366,6 +8402,7 @@ static int check_reg_allocation_locked(struct bpf_verifier_env *env, struct bpf_ ptr = reg->map_ptr; break; case PTR_TO_BTF_ID | MEM_ALLOC: + case PTR_TO_BTF_ID | MEM_ALLOC | PTR_TRUSTED: ptr = reg->btf; break; default: @@ -8596,8 +8633,9 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ case KF_ARG_PTR_TO_BTF_ID: if (!is_kfunc_trusted_args(meta)) break; - if (!reg->ref_obj_id) { - verbose(env, "R%d must be referenced\n", regno); + + if (!is_trusted_reg(reg)) { + verbose(env, "R%d must be referenced or trusted\n", regno); return -EINVAL; } fallthrough; @@ -8702,9 +8740,13 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ break; case KF_ARG_PTR_TO_BTF_ID: /* Only base_type is checked, further checks are done here */ - if (reg->type != PTR_TO_BTF_ID && - (!reg2btf_ids[base_type(reg->type)] || type_flag(reg->type))) { - verbose(env, "arg#%d expected pointer to btf or socket\n", i); + if ((base_type(reg->type) != PTR_TO_BTF_ID || + bpf_type_has_unsafe_modifiers(reg->type)) && + !reg2btf_ids[base_type(reg->type)]) { + verbose(env, "arg#%d is %s ", i, reg_type_str(env, reg->type)); + verbose(env, "expected %s or socket\n", + reg_type_str(env, base_type(reg->type) | + (type_flag(reg->type) & BPF_REG_TRUSTED_MODIFIERS))); return -EINVAL; } ret = process_kf_arg_ptr_to_btf_id(env, reg, ref_t, ref_tname, ref_id, meta, i); @@ -14713,6 +14755,7 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) break; case PTR_TO_BTF_ID: case PTR_TO_BTF_ID | PTR_UNTRUSTED: + case PTR_TO_BTF_ID | PTR_TRUSTED: /* PTR_TO_BTF_ID | MEM_ALLOC always has a valid lifetime, unlike * PTR_TO_BTF_ID, and an active ref_obj_id, but the same cannot * be said once it is marked PTR_UNTRUSTED, hence we must handle @@ -14720,6 +14763,8 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) * for this case. */ case PTR_TO_BTF_ID | MEM_ALLOC | PTR_UNTRUSTED: + case PTR_TO_BTF_ID | PTR_UNTRUSTED | PTR_TRUSTED: + case PTR_TO_BTF_ID | PTR_UNTRUSTED | MEM_ALLOC | PTR_TRUSTED: if (type == BPF_READ) { insn->code = BPF_LDX | BPF_PROBE_MEM | BPF_SIZE((insn)->code); diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index f2d8d070d024..5b9008bc597b 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -774,7 +774,7 @@ BPF_CALL_0(bpf_get_current_task_btf) const struct bpf_func_proto bpf_get_current_task_btf_proto = { .func = bpf_get_current_task_btf, .gpl_only = true, - .ret_type = RET_PTR_TO_BTF_ID, + .ret_type = RET_PTR_TO_BTF_ID_TRUSTED, .ret_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK], }; diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c index d15c91de995f..4517d2bd186a 100644 --- a/net/ipv4/bpf_tcp_ca.c +++ b/net/ipv4/bpf_tcp_ca.c @@ -61,7 +61,9 @@ static bool bpf_tcp_ca_is_valid_access(int off, int size, if (!bpf_tracing_btf_ctx_access(off, size, type, prog, info)) return false; - if (info->reg_type == PTR_TO_BTF_ID && info->btf_id == sock_id) + if (base_type(info->reg_type) == PTR_TO_BTF_ID && + !bpf_type_has_unsafe_modifiers(info->reg_type) && + info->btf_id == sock_id) /* promote it to tcp_sock */ info->btf_id = tcp_sock_id; diff --git a/tools/testing/selftests/bpf/verifier/calls.c b/tools/testing/selftests/bpf/verifier/calls.c index 86d6fef2e3b4..3193915c5ee6 100644 --- a/tools/testing/selftests/bpf/verifier/calls.c +++ b/tools/testing/selftests/bpf/verifier/calls.c @@ -109,7 +109,7 @@ }, .prog_type = BPF_PROG_TYPE_SCHED_CLS, .result = REJECT, - .errstr = "arg#0 expected pointer to btf or socket", + .errstr = "arg#0 is ptr_or_null_ expected ptr_ or socket", .fixup_kfunc_btf_id = { { "bpf_kfunc_call_test_acquire", 3 }, { "bpf_kfunc_call_test_release", 5 }, diff --git a/tools/testing/selftests/bpf/verifier/ref_tracking.c b/tools/testing/selftests/bpf/verifier/ref_tracking.c index 55cba01c99d5..9540164712b7 100644 --- a/tools/testing/selftests/bpf/verifier/ref_tracking.c +++ b/tools/testing/selftests/bpf/verifier/ref_tracking.c @@ -142,7 +142,7 @@ .kfunc = "bpf", .expected_attach_type = BPF_LSM_MAC, .flags = BPF_F_SLEEPABLE, - .errstr = "arg#0 expected pointer to btf or socket", + .errstr = "arg#0 is ptr_or_null_ expected ptr_ or socket", .fixup_kfunc_btf_id = { { "bpf_lookup_user_key", 2 }, { "bpf_key_put", 4 }, @@ -163,7 +163,7 @@ .kfunc = "bpf", .expected_attach_type = BPF_LSM_MAC, .flags = BPF_F_SLEEPABLE, - .errstr = "arg#0 expected pointer to btf or socket", + .errstr = "arg#0 is ptr_or_null_ expected ptr_ or socket", .fixup_kfunc_btf_id = { { "bpf_lookup_system_key", 1 }, { "bpf_key_put", 3 }, From 90660309b0c76c564a31a21f3a81d6641a9acaa0 Mon Sep 17 00:00:00 2001 From: David Vernet Date: Sat, 19 Nov 2022 23:10:03 -0600 Subject: [PATCH 056/101] bpf: Add kfuncs for storing struct task_struct * as a kptr Now that BPF supports adding new kernel functions with kfuncs, and storing kernel objects in maps with kptrs, we can add a set of kfuncs which allow struct task_struct objects to be stored in maps as referenced kptrs. The possible use cases for doing this are plentiful. During tracing, for example, it would be useful to be able to collect some tasks that performed a certain operation, and then periodically summarize who they are, which cgroup they're in, how much CPU time they've utilized, etc. In order to enable this, this patch adds three new kfuncs: struct task_struct *bpf_task_acquire(struct task_struct *p); struct task_struct *bpf_task_kptr_get(struct task_struct **pp); void bpf_task_release(struct task_struct *p); A follow-on patch will add selftests validating these kfuncs. Signed-off-by: David Vernet Link: https://lore.kernel.org/r/20221120051004.3605026-4-void@manifault.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/helpers.c | 78 ++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 75 insertions(+), 3 deletions(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 212e791d7452..89a95f3d854c 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1824,6 +1824,63 @@ struct bpf_list_node *bpf_list_pop_back(struct bpf_list_head *head) return __bpf_list_del(head, true); } +/** + * bpf_task_acquire - Acquire a reference to a task. A task acquired by this + * kfunc which is not stored in a map as a kptr, must be released by calling + * bpf_task_release(). + * @p: The task on which a reference is being acquired. + */ +struct task_struct *bpf_task_acquire(struct task_struct *p) +{ + refcount_inc(&p->rcu_users); + return p; +} + +/** + * bpf_task_kptr_get - Acquire a reference on a struct task_struct kptr. A task + * kptr acquired by this kfunc which is not subsequently stored in a map, must + * be released by calling bpf_task_release(). + * @pp: A pointer to a task kptr on which a reference is being acquired. + */ +struct task_struct *bpf_task_kptr_get(struct task_struct **pp) +{ + struct task_struct *p; + + rcu_read_lock(); + p = READ_ONCE(*pp); + + /* Another context could remove the task from the map and release it at + * any time, including after we've done the lookup above. This is safe + * because we're in an RCU read region, so the task is guaranteed to + * remain valid until at least the rcu_read_unlock() below. + */ + if (p && !refcount_inc_not_zero(&p->rcu_users)) + /* If the task had been removed from the map and freed as + * described above, refcount_inc_not_zero() will return false. + * The task will be freed at some point after the current RCU + * gp has ended, so just return NULL to the user. + */ + p = NULL; + rcu_read_unlock(); + + return p; +} + +/** + * bpf_task_release - Release the reference acquired on a struct task_struct *. + * If this kfunc is invoked in an RCU read region, the task_struct is + * guaranteed to not be freed until the current grace period has ended, even if + * its refcount drops to 0. + * @p: The task on which a reference is being released. + */ +void bpf_task_release(struct task_struct *p) +{ + if (!p) + return; + + put_task_struct_rcu_user(p); +} + __diag_pop(); BTF_SET8_START(generic_btf_ids) @@ -1836,6 +1893,9 @@ BTF_ID_FLAGS(func, bpf_list_push_front) BTF_ID_FLAGS(func, bpf_list_push_back) BTF_ID_FLAGS(func, bpf_list_pop_front, KF_ACQUIRE | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_list_pop_back, KF_ACQUIRE | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_task_acquire, KF_ACQUIRE | KF_TRUSTED_ARGS) +BTF_ID_FLAGS(func, bpf_task_kptr_get, KF_ACQUIRE | KF_KPTR_GET | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_task_release, KF_RELEASE) BTF_SET8_END(generic_btf_ids) static const struct btf_kfunc_id_set generic_kfunc_set = { @@ -1843,14 +1903,26 @@ static const struct btf_kfunc_id_set generic_kfunc_set = { .set = &generic_btf_ids, }; +BTF_ID_LIST(generic_dtor_ids) +BTF_ID(struct, task_struct) +BTF_ID(func, bpf_task_release) + static int __init kfunc_init(void) { int ret; + const struct btf_id_dtor_kfunc generic_dtors[] = { + { + .btf_id = generic_dtor_ids[0], + .kfunc_btf_id = generic_dtor_ids[1] + }, + }; ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &generic_kfunc_set); - if (ret) - return ret; - return register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &generic_kfunc_set); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &generic_kfunc_set); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &generic_kfunc_set); + return ret ?: register_btf_id_dtor_kfuncs(generic_dtors, + ARRAY_SIZE(generic_dtors), + THIS_MODULE); } late_initcall(kfunc_init); From fe147956fca4604b920e6be652abc9bea8ce8952 Mon Sep 17 00:00:00 2001 From: David Vernet Date: Sat, 19 Nov 2022 23:10:04 -0600 Subject: [PATCH 057/101] bpf/selftests: Add selftests for new task kfuncs A previous change added a series of kfuncs for storing struct task_struct objects as referenced kptrs. This patch adds a new task_kfunc test suite for validating their expected behavior. Signed-off-by: David Vernet Link: https://lore.kernel.org/r/20221120051004.3605026-5-void@manifault.com Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/DENYLIST.s390x | 1 + .../selftests/bpf/prog_tests/task_kfunc.c | 159 +++++++++++ .../selftests/bpf/progs/task_kfunc_common.h | 71 +++++ .../selftests/bpf/progs/task_kfunc_failure.c | 260 ++++++++++++++++++ .../selftests/bpf/progs/task_kfunc_success.c | 149 ++++++++++ 5 files changed, 640 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/task_kfunc.c create mode 100644 tools/testing/selftests/bpf/progs/task_kfunc_common.h create mode 100644 tools/testing/selftests/bpf/progs/task_kfunc_failure.c create mode 100644 tools/testing/selftests/bpf/progs/task_kfunc_success.c diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x index 072243af93b0..f70a677b38e5 100644 --- a/tools/testing/selftests/bpf/DENYLIST.s390x +++ b/tools/testing/selftests/bpf/DENYLIST.s390x @@ -54,6 +54,7 @@ skc_to_unix_sock # could not attach BPF object unexpecte socket_cookie # prog_attach unexpected error: -524 (trampoline) stacktrace_build_id # compare_map_keys stackid_hmap vs. stackmap err -2 errno 2 (?) tailcalls # tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls (?) +task_kfunc # JIT does not support calling kernel function task_local_storage # failed to auto-attach program 'trace_exit_creds': -524 (trampoline) test_bpffs # bpffs test failed 255 (iterator) test_bprm_opts # failed to auto-attach program 'secure_exec': -524 (trampoline) diff --git a/tools/testing/selftests/bpf/prog_tests/task_kfunc.c b/tools/testing/selftests/bpf/prog_tests/task_kfunc.c new file mode 100644 index 000000000000..4994fe6092cc --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/task_kfunc.c @@ -0,0 +1,159 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ + +#define _GNU_SOURCE +#include +#include +#include + +#include "task_kfunc_failure.skel.h" +#include "task_kfunc_success.skel.h" + +static size_t log_buf_sz = 1 << 20; /* 1 MB */ +static char obj_log_buf[1048576]; + +static struct task_kfunc_success *open_load_task_kfunc_skel(void) +{ + struct task_kfunc_success *skel; + int err; + + skel = task_kfunc_success__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return NULL; + + skel->bss->pid = getpid(); + + err = task_kfunc_success__load(skel); + if (!ASSERT_OK(err, "skel_load")) + goto cleanup; + + return skel; + +cleanup: + task_kfunc_success__destroy(skel); + return NULL; +} + +static void run_success_test(const char *prog_name) +{ + struct task_kfunc_success *skel; + int status; + pid_t child_pid; + struct bpf_program *prog; + struct bpf_link *link = NULL; + + skel = open_load_task_kfunc_skel(); + if (!ASSERT_OK_PTR(skel, "open_load_skel")) + return; + + if (!ASSERT_OK(skel->bss->err, "pre_spawn_err")) + goto cleanup; + + prog = bpf_object__find_program_by_name(skel->obj, prog_name); + if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name")) + goto cleanup; + + link = bpf_program__attach(prog); + if (!ASSERT_OK_PTR(link, "attached_link")) + goto cleanup; + + child_pid = fork(); + if (!ASSERT_GT(child_pid, -1, "child_pid")) + goto cleanup; + if (child_pid == 0) + _exit(0); + waitpid(child_pid, &status, 0); + + ASSERT_OK(skel->bss->err, "post_wait_err"); + +cleanup: + bpf_link__destroy(link); + task_kfunc_success__destroy(skel); +} + +static const char * const success_tests[] = { + "test_task_acquire_release_argument", + "test_task_acquire_release_current", + "test_task_acquire_leave_in_map", + "test_task_xchg_release", + "test_task_get_release", + "test_task_current_acquire_release", +}; + +static struct { + const char *prog_name; + const char *expected_err_msg; +} failure_tests[] = { + {"task_kfunc_acquire_untrusted", "R1 must be referenced or trusted"}, + {"task_kfunc_acquire_fp", "arg#0 pointer type STRUCT task_struct must point"}, + {"task_kfunc_acquire_unsafe_kretprobe", "reg type unsupported for arg#0 function"}, + {"task_kfunc_acquire_trusted_walked", "R1 must be referenced or trusted"}, + {"task_kfunc_acquire_null", "arg#0 pointer type STRUCT task_struct must point"}, + {"task_kfunc_acquire_unreleased", "Unreleased reference"}, + {"task_kfunc_get_non_kptr_param", "arg#0 expected pointer to map value"}, + {"task_kfunc_get_non_kptr_acquired", "arg#0 expected pointer to map value"}, + {"task_kfunc_get_null", "arg#0 expected pointer to map value"}, + {"task_kfunc_xchg_unreleased", "Unreleased reference"}, + {"task_kfunc_get_unreleased", "Unreleased reference"}, + {"task_kfunc_release_untrusted", "arg#0 is untrusted_ptr_or_null_ expected ptr_ or socket"}, + {"task_kfunc_release_fp", "arg#0 pointer type STRUCT task_struct must point"}, + {"task_kfunc_release_null", "arg#0 is ptr_or_null_ expected ptr_ or socket"}, + {"task_kfunc_release_unacquired", "release kernel function bpf_task_release expects"}, +}; + +static void verify_fail(const char *prog_name, const char *expected_err_msg) +{ + LIBBPF_OPTS(bpf_object_open_opts, opts); + struct task_kfunc_failure *skel; + int err, i; + + opts.kernel_log_buf = obj_log_buf; + opts.kernel_log_size = log_buf_sz; + opts.kernel_log_level = 1; + + skel = task_kfunc_failure__open_opts(&opts); + if (!ASSERT_OK_PTR(skel, "task_kfunc_failure__open_opts")) + goto cleanup; + + for (i = 0; i < ARRAY_SIZE(failure_tests); i++) { + struct bpf_program *prog; + const char *curr_name = failure_tests[i].prog_name; + + prog = bpf_object__find_program_by_name(skel->obj, curr_name); + if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name")) + goto cleanup; + + bpf_program__set_autoload(prog, !strcmp(curr_name, prog_name)); + } + + err = task_kfunc_failure__load(skel); + if (!ASSERT_ERR(err, "unexpected load success")) + goto cleanup; + + if (!ASSERT_OK_PTR(strstr(obj_log_buf, expected_err_msg), "expected_err_msg")) { + fprintf(stderr, "Expected err_msg: %s\n", expected_err_msg); + fprintf(stderr, "Verifier output: %s\n", obj_log_buf); + } + +cleanup: + task_kfunc_failure__destroy(skel); +} + +void test_task_kfunc(void) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(success_tests); i++) { + if (!test__start_subtest(success_tests[i])) + continue; + + run_success_test(success_tests[i]); + } + + for (i = 0; i < ARRAY_SIZE(failure_tests); i++) { + if (!test__start_subtest(failure_tests[i].prog_name)) + continue; + + verify_fail(failure_tests[i].prog_name, failure_tests[i].expected_err_msg); + } +} diff --git a/tools/testing/selftests/bpf/progs/task_kfunc_common.h b/tools/testing/selftests/bpf/progs/task_kfunc_common.h new file mode 100644 index 000000000000..160d6dde00be --- /dev/null +++ b/tools/testing/selftests/bpf/progs/task_kfunc_common.h @@ -0,0 +1,71 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ + +#ifndef _TASK_KFUNC_COMMON_H +#define _TASK_KFUNC_COMMON_H + +#include +#include +#include +#include + +struct __tasks_kfunc_map_value { + struct task_struct __kptr_ref * task; +}; + +struct hash_map { + __uint(type, BPF_MAP_TYPE_HASH); + __type(key, int); + __type(value, struct __tasks_kfunc_map_value); + __uint(max_entries, 1); +} __tasks_kfunc_map SEC(".maps"); + +struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym; +struct task_struct *bpf_task_kptr_get(struct task_struct **pp) __ksym; +void bpf_task_release(struct task_struct *p) __ksym; + +static inline struct __tasks_kfunc_map_value *tasks_kfunc_map_value_lookup(struct task_struct *p) +{ + s32 pid; + long status; + + status = bpf_probe_read_kernel(&pid, sizeof(pid), &p->pid); + if (status) + return NULL; + + return bpf_map_lookup_elem(&__tasks_kfunc_map, &pid); +} + +static inline int tasks_kfunc_map_insert(struct task_struct *p) +{ + struct __tasks_kfunc_map_value local, *v; + long status; + struct task_struct *acquired, *old; + s32 pid; + + status = bpf_probe_read_kernel(&pid, sizeof(pid), &p->pid); + if (status) + return status; + + local.task = NULL; + status = bpf_map_update_elem(&__tasks_kfunc_map, &pid, &local, BPF_NOEXIST); + if (status) + return status; + + v = bpf_map_lookup_elem(&__tasks_kfunc_map, &pid); + if (!v) { + bpf_map_delete_elem(&__tasks_kfunc_map, &pid); + return -ENOENT; + } + + acquired = bpf_task_acquire(p); + old = bpf_kptr_xchg(&v->task, acquired); + if (old) { + bpf_task_release(old); + return -EEXIST; + } + + return 0; +} + +#endif /* _TASK_KFUNC_COMMON_H */ diff --git a/tools/testing/selftests/bpf/progs/task_kfunc_failure.c b/tools/testing/selftests/bpf/progs/task_kfunc_failure.c new file mode 100644 index 000000000000..93e934ddfcb6 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/task_kfunc_failure.c @@ -0,0 +1,260 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ + +#include +#include +#include + +#include "task_kfunc_common.h" + +char _license[] SEC("license") = "GPL"; + +/* Prototype for all of the program trace events below: + * + * TRACE_EVENT(task_newtask, + * TP_PROTO(struct task_struct *p, u64 clone_flags) + */ + +static struct __tasks_kfunc_map_value *insert_lookup_task(struct task_struct *task) +{ + int status; + + status = tasks_kfunc_map_insert(task); + if (status) + return NULL; + + return tasks_kfunc_map_value_lookup(task); +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(task_kfunc_acquire_untrusted, struct task_struct *task, u64 clone_flags) +{ + struct task_struct *acquired; + struct __tasks_kfunc_map_value *v; + + v = insert_lookup_task(task); + if (!v) + return 0; + + /* Can't invoke bpf_task_acquire() on an untrusted pointer. */ + acquired = bpf_task_acquire(v->task); + bpf_task_release(acquired); + + return 0; +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(task_kfunc_acquire_fp, struct task_struct *task, u64 clone_flags) +{ + struct task_struct *acquired, *stack_task = (struct task_struct *)&clone_flags; + + /* Can't invoke bpf_task_acquire() on a random frame pointer. */ + acquired = bpf_task_acquire((struct task_struct *)&stack_task); + bpf_task_release(acquired); + + return 0; +} + +SEC("kretprobe/free_task") +int BPF_PROG(task_kfunc_acquire_unsafe_kretprobe, struct task_struct *task, u64 clone_flags) +{ + struct task_struct *acquired; + + acquired = bpf_task_acquire(task); + /* Can't release a bpf_task_acquire()'d task without a NULL check. */ + bpf_task_release(acquired); + + return 0; +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(task_kfunc_acquire_trusted_walked, struct task_struct *task, u64 clone_flags) +{ + struct task_struct *acquired; + + /* Can't invoke bpf_task_acquire() on a trusted pointer obtained from walking a struct. */ + acquired = bpf_task_acquire(task->last_wakee); + bpf_task_release(acquired); + + return 0; +} + + +SEC("tp_btf/task_newtask") +int BPF_PROG(task_kfunc_acquire_null, struct task_struct *task, u64 clone_flags) +{ + struct task_struct *acquired; + + /* Can't invoke bpf_task_acquire() on a NULL pointer. */ + acquired = bpf_task_acquire(NULL); + if (!acquired) + return 0; + bpf_task_release(acquired); + + return 0; +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(task_kfunc_acquire_unreleased, struct task_struct *task, u64 clone_flags) +{ + struct task_struct *acquired; + + acquired = bpf_task_acquire(task); + + /* Acquired task is never released. */ + + return 0; +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(task_kfunc_get_non_kptr_param, struct task_struct *task, u64 clone_flags) +{ + struct task_struct *kptr; + + /* Cannot use bpf_task_kptr_get() on a non-kptr, even on a valid task. */ + kptr = bpf_task_kptr_get(&task); + if (!kptr) + return 0; + + bpf_task_release(kptr); + + return 0; +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(task_kfunc_get_non_kptr_acquired, struct task_struct *task, u64 clone_flags) +{ + struct task_struct *kptr, *acquired; + + acquired = bpf_task_acquire(task); + + /* Cannot use bpf_task_kptr_get() on a non-kptr, even if it was acquired. */ + kptr = bpf_task_kptr_get(&acquired); + bpf_task_release(acquired); + if (!kptr) + return 0; + + bpf_task_release(kptr); + + return 0; +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(task_kfunc_get_null, struct task_struct *task, u64 clone_flags) +{ + struct task_struct *kptr; + + /* Cannot use bpf_task_kptr_get() on a NULL pointer. */ + kptr = bpf_task_kptr_get(NULL); + if (!kptr) + return 0; + + bpf_task_release(kptr); + + return 0; +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(task_kfunc_xchg_unreleased, struct task_struct *task, u64 clone_flags) +{ + struct task_struct *kptr; + struct __tasks_kfunc_map_value *v; + + v = insert_lookup_task(task); + if (!v) + return 0; + + kptr = bpf_kptr_xchg(&v->task, NULL); + if (!kptr) + return 0; + + /* Kptr retrieved from map is never released. */ + + return 0; +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(task_kfunc_get_unreleased, struct task_struct *task, u64 clone_flags) +{ + struct task_struct *kptr; + struct __tasks_kfunc_map_value *v; + + v = insert_lookup_task(task); + if (!v) + return 0; + + kptr = bpf_task_kptr_get(&v->task); + if (!kptr) + return 0; + + /* Kptr acquired above is never released. */ + + return 0; +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(task_kfunc_release_untrusted, struct task_struct *task, u64 clone_flags) +{ + struct __tasks_kfunc_map_value *v; + + v = insert_lookup_task(task); + if (!v) + return 0; + + /* Can't invoke bpf_task_release() on an untrusted pointer. */ + bpf_task_release(v->task); + + return 0; +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(task_kfunc_release_fp, struct task_struct *task, u64 clone_flags) +{ + struct task_struct *acquired = (struct task_struct *)&clone_flags; + + /* Cannot release random frame pointer. */ + bpf_task_release(acquired); + + return 0; +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(task_kfunc_release_null, struct task_struct *task, u64 clone_flags) +{ + struct __tasks_kfunc_map_value local, *v; + long status; + struct task_struct *acquired, *old; + s32 pid; + + status = bpf_probe_read_kernel(&pid, sizeof(pid), &task->pid); + if (status) + return 0; + + local.task = NULL; + status = bpf_map_update_elem(&__tasks_kfunc_map, &pid, &local, BPF_NOEXIST); + if (status) + return status; + + v = bpf_map_lookup_elem(&__tasks_kfunc_map, &pid); + if (!v) + return -ENOENT; + + acquired = bpf_task_acquire(task); + + old = bpf_kptr_xchg(&v->task, acquired); + + /* old cannot be passed to bpf_task_release() without a NULL check. */ + bpf_task_release(old); + bpf_task_release(old); + + return 0; +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(task_kfunc_release_unacquired, struct task_struct *task, u64 clone_flags) +{ + /* Cannot release trusted task pointer which was not acquired. */ + bpf_task_release(task); + + return 0; +} diff --git a/tools/testing/selftests/bpf/progs/task_kfunc_success.c b/tools/testing/selftests/bpf/progs/task_kfunc_success.c new file mode 100644 index 000000000000..be4534b5ba2e --- /dev/null +++ b/tools/testing/selftests/bpf/progs/task_kfunc_success.c @@ -0,0 +1,149 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ + +#include +#include +#include + +#include "task_kfunc_common.h" + +char _license[] SEC("license") = "GPL"; + +int err, pid; + +/* Prototype for all of the program trace events below: + * + * TRACE_EVENT(task_newtask, + * TP_PROTO(struct task_struct *p, u64 clone_flags) + */ + +static bool is_test_kfunc_task(void) +{ + int cur_pid = bpf_get_current_pid_tgid() >> 32; + + return pid == cur_pid; +} + +static int test_acquire_release(struct task_struct *task) +{ + struct task_struct *acquired; + + acquired = bpf_task_acquire(task); + bpf_task_release(acquired); + + return 0; +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(test_task_acquire_release_argument, struct task_struct *task, u64 clone_flags) +{ + if (!is_test_kfunc_task()) + return 0; + + return test_acquire_release(task); +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(test_task_acquire_release_current, struct task_struct *task, u64 clone_flags) +{ + if (!is_test_kfunc_task()) + return 0; + + return test_acquire_release(bpf_get_current_task_btf()); +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(test_task_acquire_leave_in_map, struct task_struct *task, u64 clone_flags) +{ + long status; + + if (!is_test_kfunc_task()) + return 0; + + status = tasks_kfunc_map_insert(task); + if (status) + err = 1; + + return 0; +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(test_task_xchg_release, struct task_struct *task, u64 clone_flags) +{ + struct task_struct *kptr; + struct __tasks_kfunc_map_value *v; + long status; + + if (!is_test_kfunc_task()) + return 0; + + status = tasks_kfunc_map_insert(task); + if (status) { + err = 1; + return 0; + } + + v = tasks_kfunc_map_value_lookup(task); + if (!v) { + err = 2; + return 0; + } + + kptr = bpf_kptr_xchg(&v->task, NULL); + if (!kptr) { + err = 3; + return 0; + } + + bpf_task_release(kptr); + + return 0; +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(test_task_get_release, struct task_struct *task, u64 clone_flags) +{ + struct task_struct *kptr; + struct __tasks_kfunc_map_value *v; + long status; + + if (!is_test_kfunc_task()) + return 0; + + status = tasks_kfunc_map_insert(task); + if (status) { + err = 1; + return 0; + } + + v = tasks_kfunc_map_value_lookup(task); + if (!v) { + err = 2; + return 0; + } + + kptr = bpf_task_kptr_get(&v->task); + if (!kptr) { + err = 3; + return 0; + } + + bpf_task_release(kptr); + + return 0; +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(test_task_current_acquire_release, struct task_struct *task, u64 clone_flags) +{ + struct task_struct *current, *acquired; + + if (!is_test_kfunc_task()) + return 0; + + current = bpf_get_current_task_btf(); + acquired = bpf_task_acquire(current); + bpf_task_release(acquired); + + return 0; +} From e181d3f143f7957a73c8365829249d8084602606 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Mon, 21 Nov 2022 02:56:10 +0530 Subject: [PATCH 058/101] bpf: Disallow bpf_obj_new_impl call when bpf_mem_alloc_init fails In the unlikely event that bpf_global_ma is not correctly initialized, instead of checking the boolean everytime bpf_obj_new_impl is called, simply check it while loading the program and return an error if bpf_global_ma_set is false. Suggested-by: Alexei Starovoitov Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221120212610.2361700-1-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/helpers.c | 2 -- kernel/bpf/verifier.c | 3 +++ 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 89a95f3d854c..3d4edd314450 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1760,8 +1760,6 @@ void *bpf_obj_new_impl(u64 local_type_id__k, void *meta__ign) u64 size = local_type_id__k; void *p; - if (unlikely(!bpf_global_ma_set)) - return NULL; p = bpf_mem_alloc(&bpf_global_ma, size); if (!p) return NULL; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 5bc9d84d7924..eb090af35477 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -8878,6 +8878,9 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, struct btf *ret_btf; u32 ret_btf_id; + if (unlikely(!bpf_global_ma_set)) + return -ENOMEM; + if (((u64)(u32)meta.arg_constant.value) != meta.arg_constant.value) { verbose(env, "local type ID argument must be in range [0, U32_MAX]\n"); return -EINVAL; From cfe1456440c8feaf6558577a400745d774418379 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Sun, 20 Nov 2022 11:54:26 -0800 Subject: [PATCH 059/101] bpf: Add support for kfunc set with common btf_ids Later on, we will introduce kfuncs bpf_cast_to_kern_ctx() and bpf_rdonly_cast() which apply to all program types. Currently kfunc set only supports individual prog types. This patch added support for kfunc applying to all program types. Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20221120195426.3113828-1-yhs@fb.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/btf.c | 8 ++++++++ kernel/bpf/helpers.c | 12 +++++++++++- 2 files changed, 19 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index d52054ec69c9..1c78d4df9e18 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -199,6 +199,7 @@ DEFINE_IDR(btf_idr); DEFINE_SPINLOCK(btf_idr_lock); enum btf_kfunc_hook { + BTF_KFUNC_HOOK_COMMON, BTF_KFUNC_HOOK_XDP, BTF_KFUNC_HOOK_TC, BTF_KFUNC_HOOK_STRUCT_OPS, @@ -7531,6 +7532,8 @@ static u32 *__btf_kfunc_id_set_contains(const struct btf *btf, static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type) { switch (prog_type) { + case BPF_PROG_TYPE_UNSPEC: + return BTF_KFUNC_HOOK_COMMON; case BPF_PROG_TYPE_XDP: return BTF_KFUNC_HOOK_XDP; case BPF_PROG_TYPE_SCHED_CLS: @@ -7559,6 +7562,11 @@ u32 *btf_kfunc_id_set_contains(const struct btf *btf, u32 kfunc_btf_id) { enum btf_kfunc_hook hook; + u32 *kfunc_flags; + + kfunc_flags = __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_COMMON, kfunc_btf_id); + if (kfunc_flags) + return kfunc_flags; hook = bpf_prog_type_to_kfunc_hook(prog_type); return __btf_kfunc_id_set_contains(btf, hook, kfunc_btf_id); diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 3d4edd314450..8e0d80b6bf09 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1901,10 +1901,19 @@ static const struct btf_kfunc_id_set generic_kfunc_set = { .set = &generic_btf_ids, }; + BTF_ID_LIST(generic_dtor_ids) BTF_ID(struct, task_struct) BTF_ID(func, bpf_task_release) +BTF_SET8_START(common_btf_ids) +BTF_SET8_END(common_btf_ids) + +static const struct btf_kfunc_id_set common_kfunc_set = { + .owner = THIS_MODULE, + .set = &common_btf_ids, +}; + static int __init kfunc_init(void) { int ret; @@ -1918,9 +1927,10 @@ static int __init kfunc_init(void) ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &generic_kfunc_set); ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &generic_kfunc_set); ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &generic_kfunc_set); - return ret ?: register_btf_id_dtor_kfuncs(generic_dtors, + ret = ret ?: register_btf_id_dtor_kfuncs(generic_dtors, ARRAY_SIZE(generic_dtors), THIS_MODULE); + return ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_UNSPEC, &common_kfunc_set); } late_initcall(kfunc_init); From fd264ca020948a743e4c36731dfdecc4a812153c Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Sun, 20 Nov 2022 11:54:32 -0800 Subject: [PATCH 060/101] bpf: Add a kfunc to type cast from bpf uapi ctx to kernel ctx Implement bpf_cast_to_kern_ctx() kfunc which does a type cast of a uapi ctx object to the corresponding kernel ctx. Previously if users want to access some data available in kctx but not in uapi ctx, bpf_probe_read_kernel() helper is needed. The introduction of bpf_cast_to_kern_ctx() allows direct memory access which makes code simpler and easier to understand. Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20221120195432.3113982-1-yhs@fb.com Signed-off-by: Alexei Starovoitov --- include/linux/btf.h | 5 +++++ kernel/bpf/btf.c | 20 ++++++++++++++++++++ kernel/bpf/helpers.c | 6 ++++++ kernel/bpf/verifier.c | 22 ++++++++++++++++++++++ 4 files changed, 53 insertions(+) diff --git a/include/linux/btf.h b/include/linux/btf.h index d38aa4251c28..9ed00077db6e 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -487,6 +487,7 @@ const struct btf_member * btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf, const struct btf_type *t, enum bpf_prog_type prog_type, int arg); +int get_kern_ctx_btf_id(struct bpf_verifier_log *log, enum bpf_prog_type prog_type); bool btf_types_are_same(const struct btf *btf1, u32 id1, const struct btf *btf2, u32 id2); #else @@ -531,6 +532,10 @@ btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf, { return NULL; } +static inline int get_kern_ctx_btf_id(struct bpf_verifier_log *log, + enum bpf_prog_type prog_type) { + return -EINVAL; +} static inline bool btf_types_are_same(const struct btf *btf1, u32 id1, const struct btf *btf2, u32 id2) { diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 1c78d4df9e18..1a59cc7ad730 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -5603,6 +5603,26 @@ static int btf_translate_to_vmlinux(struct bpf_verifier_log *log, return kern_ctx_type->type; } +int get_kern_ctx_btf_id(struct bpf_verifier_log *log, enum bpf_prog_type prog_type) +{ + const struct btf_member *kctx_member; + const struct btf_type *conv_struct; + const struct btf_type *kctx_type; + u32 kctx_type_id; + + conv_struct = bpf_ctx_convert.t; + /* get member for kernel ctx type */ + kctx_member = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2 + 1; + kctx_type_id = kctx_member->type; + kctx_type = btf_type_by_id(btf_vmlinux, kctx_type_id); + if (!btf_type_is_struct(kctx_type)) { + bpf_log(log, "kern ctx type id %u is not a struct\n", kctx_type_id); + return -EINVAL; + } + + return kctx_type_id; +} + BTF_ID_LIST(bpf_ctx_convert_btf_id) BTF_ID(struct, bpf_ctx_convert) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 8e0d80b6bf09..e45e72676f5a 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1879,6 +1879,11 @@ void bpf_task_release(struct task_struct *p) put_task_struct_rcu_user(p); } +void *bpf_cast_to_kern_ctx(void *obj) +{ + return obj; +} + __diag_pop(); BTF_SET8_START(generic_btf_ids) @@ -1907,6 +1912,7 @@ BTF_ID(struct, task_struct) BTF_ID(func, bpf_task_release) BTF_SET8_START(common_btf_ids) +BTF_ID_FLAGS(func, bpf_cast_to_kern_ctx) BTF_SET8_END(common_btf_ids) static const struct btf_kfunc_id_set common_kfunc_set = { diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index eb090af35477..d63cc0fb0a9c 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -7907,6 +7907,7 @@ struct bpf_kfunc_call_arg_meta { u32 ref_obj_id; u8 release_regno; bool r0_rdonly; + u32 ret_btf_id; u64 r0_size; struct { u64 value; @@ -8151,6 +8152,7 @@ enum special_kfunc_type { KF_bpf_list_push_back, KF_bpf_list_pop_front, KF_bpf_list_pop_back, + KF_bpf_cast_to_kern_ctx, }; BTF_SET_START(special_kfunc_set) @@ -8160,6 +8162,7 @@ BTF_ID(func, bpf_list_push_front) BTF_ID(func, bpf_list_push_back) BTF_ID(func, bpf_list_pop_front) BTF_ID(func, bpf_list_pop_back) +BTF_ID(func, bpf_cast_to_kern_ctx) BTF_SET_END(special_kfunc_set) BTF_ID_LIST(special_kfunc_list) @@ -8169,6 +8172,7 @@ BTF_ID(func, bpf_list_push_front) BTF_ID(func, bpf_list_push_back) BTF_ID(func, bpf_list_pop_front) BTF_ID(func, bpf_list_pop_back) +BTF_ID(func, bpf_cast_to_kern_ctx) static enum kfunc_ptr_arg_type get_kfunc_ptr_arg_type(struct bpf_verifier_env *env, @@ -8182,6 +8186,9 @@ get_kfunc_ptr_arg_type(struct bpf_verifier_env *env, struct bpf_reg_state *reg = ®s[regno]; bool arg_mem_size = false; + if (meta->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx]) + return KF_ARG_PTR_TO_CTX; + /* In this function, we verify the kfunc's BTF as per the argument type, * leaving the rest of the verification with respect to the register * type to our caller. When a set of conditions hold in the BTF type of @@ -8668,6 +8675,13 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ verbose(env, "arg#%d expected pointer to ctx, but got %s\n", i, btf_type_str(t)); return -EINVAL; } + + if (meta->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx]) { + ret = get_kern_ctx_btf_id(&env->log, resolve_prog_type(env->prog)); + if (ret < 0) + return -EINVAL; + meta->ret_btf_id = ret; + } break; case KF_ARG_PTR_TO_ALLOC_BTF_ID: if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) { @@ -8922,6 +8936,11 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, regs[BPF_REG_0].btf = field->list_head.btf; regs[BPF_REG_0].btf_id = field->list_head.value_btf_id; regs[BPF_REG_0].off = field->list_head.node_offset; + } else if (meta.func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx]) { + mark_reg_known_zero(env, regs, BPF_REG_0); + regs[BPF_REG_0].type = PTR_TO_BTF_ID | PTR_TRUSTED; + regs[BPF_REG_0].btf = desc_btf; + regs[BPF_REG_0].btf_id = meta.ret_btf_id; } else { verbose(env, "kernel function %s unhandled dynamic return type\n", meta.func_name); @@ -15175,6 +15194,9 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, insn_buf[1] = addr[1]; insn_buf[2] = *insn; *cnt = 3; + } else if (desc->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx]) { + insn_buf[0] = BPF_MOV64_REG(BPF_REG_0, BPF_REG_1); + *cnt = 1; } return 0; } From a35b9af4ec2c7f69286ef861fd2074a577e354cb Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Sun, 20 Nov 2022 11:54:37 -0800 Subject: [PATCH 061/101] bpf: Add a kfunc for generic type cast Implement bpf_rdonly_cast() which tries to cast the object to a specified type. This tries to support use case like below: #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB))) where skb_end_pointer(SKB) is a 'unsigned char *' and needs to be casted to 'struct skb_shared_info *'. The signature of bpf_rdonly_cast() looks like void *bpf_rdonly_cast(void *obj, __u32 btf_id) The function returns the same 'obj' but with PTR_TO_BTF_ID with btf_id. The verifier will ensure btf_id being a struct type. Since the supported type cast may not reflect what the 'obj' represents, the returned btf_id is marked as PTR_UNTRUSTED, so the return value and subsequent pointer chasing cannot be used as helper/kfunc arguments. Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20221120195437.3114585-1-yhs@fb.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/helpers.c | 6 ++++++ kernel/bpf/verifier.c | 20 ++++++++++++++++++-- 2 files changed, 24 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index e45e72676f5a..9e8a5557ea8d 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1884,6 +1884,11 @@ void *bpf_cast_to_kern_ctx(void *obj) return obj; } +void *bpf_rdonly_cast(void *obj__ign, u32 btf_id__k) +{ + return obj__ign; +} + __diag_pop(); BTF_SET8_START(generic_btf_ids) @@ -1913,6 +1918,7 @@ BTF_ID(func, bpf_task_release) BTF_SET8_START(common_btf_ids) BTF_ID_FLAGS(func, bpf_cast_to_kern_ctx) +BTF_ID_FLAGS(func, bpf_rdonly_cast) BTF_SET8_END(common_btf_ids) static const struct btf_kfunc_id_set common_kfunc_set = { diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index d63cc0fb0a9c..f07bec227fef 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -8153,6 +8153,7 @@ enum special_kfunc_type { KF_bpf_list_pop_front, KF_bpf_list_pop_back, KF_bpf_cast_to_kern_ctx, + KF_bpf_rdonly_cast, }; BTF_SET_START(special_kfunc_set) @@ -8163,6 +8164,7 @@ BTF_ID(func, bpf_list_push_back) BTF_ID(func, bpf_list_pop_front) BTF_ID(func, bpf_list_pop_back) BTF_ID(func, bpf_cast_to_kern_ctx) +BTF_ID(func, bpf_rdonly_cast) BTF_SET_END(special_kfunc_set) BTF_ID_LIST(special_kfunc_list) @@ -8173,6 +8175,7 @@ BTF_ID(func, bpf_list_push_back) BTF_ID(func, bpf_list_pop_front) BTF_ID(func, bpf_list_pop_back) BTF_ID(func, bpf_cast_to_kern_ctx) +BTF_ID(func, bpf_rdonly_cast) static enum kfunc_ptr_arg_type get_kfunc_ptr_arg_type(struct bpf_verifier_env *env, @@ -8809,6 +8812,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, u32 i, nargs, func_id, ptr_type_id; int err, insn_idx = *insn_idx_p; const struct btf_param *args; + const struct btf_type *ret_t; struct btf *desc_btf; u32 *kfunc_flags; @@ -8888,7 +8892,6 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, if (meta.btf == btf_vmlinux && btf_id_set_contains(&special_kfunc_set, meta.func_id)) { if (meta.func_id == special_kfunc_list[KF_bpf_obj_new_impl]) { - const struct btf_type *ret_t; struct btf *ret_btf; u32 ret_btf_id; @@ -8941,6 +8944,18 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, regs[BPF_REG_0].type = PTR_TO_BTF_ID | PTR_TRUSTED; regs[BPF_REG_0].btf = desc_btf; regs[BPF_REG_0].btf_id = meta.ret_btf_id; + } else if (meta.func_id == special_kfunc_list[KF_bpf_rdonly_cast]) { + ret_t = btf_type_by_id(desc_btf, meta.arg_constant.value); + if (!ret_t || !btf_type_is_struct(ret_t)) { + verbose(env, + "kfunc bpf_rdonly_cast type ID argument must be of a struct\n"); + return -EINVAL; + } + + mark_reg_known_zero(env, regs, BPF_REG_0); + regs[BPF_REG_0].type = PTR_TO_BTF_ID | PTR_UNTRUSTED; + regs[BPF_REG_0].btf = desc_btf; + regs[BPF_REG_0].btf_id = meta.arg_constant.value; } else { verbose(env, "kernel function %s unhandled dynamic return type\n", meta.func_name); @@ -15194,7 +15209,8 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, insn_buf[1] = addr[1]; insn_buf[2] = *insn; *cnt = 3; - } else if (desc->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx]) { + } else if (desc->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx] || + desc->func_id == special_kfunc_list[KF_bpf_rdonly_cast]) { insn_buf[0] = BPF_MOV64_REG(BPF_REG_0, BPF_REG_1); *cnt = 1; } From 58d84bee58465cc9f6a63ca3931240419497f917 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Sun, 20 Nov 2022 11:54:42 -0800 Subject: [PATCH 062/101] bpf: Add type cast unit tests Three tests are added. One is from John Fastabend ({1]) which tests tracing style access for xdp program from the kernel ctx. Another is a tc test to test both kernel ctx tracing style access and explicit non-ctx type cast. The third one is for negative tests including two tests, a tp_bpf test where the bpf_rdonly_cast() returns a untrusted ptr which cannot be used as helper argument, and a tracepoint test where the kernel ctx is a u64. Also added the test to DENYLIST.s390x since s390 does not currently support calling kernel functions in JIT mode. [1] https://lore.kernel.org/bpf/20221109215242.1279993-1-john.fastabend@gmail.com/ Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20221120195442.3114844-1-yhs@fb.com Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/DENYLIST.s390x | 1 + .../selftests/bpf/prog_tests/type_cast.c | 114 ++++++++++++++++++ tools/testing/selftests/bpf/progs/type_cast.c | 83 +++++++++++++ 3 files changed, 198 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/type_cast.c create mode 100644 tools/testing/selftests/bpf/progs/type_cast.c diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x index f70a677b38e5..12cf2159975e 100644 --- a/tools/testing/selftests/bpf/DENYLIST.s390x +++ b/tools/testing/selftests/bpf/DENYLIST.s390x @@ -71,6 +71,7 @@ trace_printk # trace_printk__load unexpected error: trace_vprintk # trace_vprintk__open_and_load unexpected error: -9 (?) tracing_struct # failed to auto-attach: -524 (trampoline) trampoline_count # prog 'prog1': failed to attach: ERROR: strerror_r(-524)=22 (trampoline) +type_cast # JIT does not support calling kernel function unpriv_bpf_disabled # fentry user_ringbuf # failed to find kernel BTF type ID of '__s390x_sys_prctl': -3 (?) verif_stats # trace_vprintk__open_and_load unexpected error: -9 (?) diff --git a/tools/testing/selftests/bpf/prog_tests/type_cast.c b/tools/testing/selftests/bpf/prog_tests/type_cast.c new file mode 100644 index 000000000000..9317d5fa2635 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/type_cast.c @@ -0,0 +1,114 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ +#include +#include +#include "type_cast.skel.h" + +static void test_xdp(void) +{ + struct type_cast *skel; + int err, prog_fd; + char buf[128]; + + LIBBPF_OPTS(bpf_test_run_opts, topts, + .data_in = &pkt_v4, + .data_size_in = sizeof(pkt_v4), + .data_out = buf, + .data_size_out = sizeof(buf), + .repeat = 1, + ); + + skel = type_cast__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + bpf_program__set_autoload(skel->progs.md_xdp, true); + err = type_cast__load(skel); + if (!ASSERT_OK(err, "skel_load")) + goto out; + + prog_fd = bpf_program__fd(skel->progs.md_xdp); + err = bpf_prog_test_run_opts(prog_fd, &topts); + ASSERT_OK(err, "test_run"); + ASSERT_EQ(topts.retval, XDP_PASS, "xdp test_run retval"); + + ASSERT_EQ(skel->bss->ifindex, 1, "xdp_md ifindex"); + ASSERT_EQ(skel->bss->ifindex, skel->bss->ingress_ifindex, "xdp_md ingress_ifindex"); + ASSERT_STREQ(skel->bss->name, "lo", "xdp_md name"); + ASSERT_NEQ(skel->bss->inum, 0, "xdp_md inum"); + +out: + type_cast__destroy(skel); +} + +static void test_tc(void) +{ + struct type_cast *skel; + int err, prog_fd; + + LIBBPF_OPTS(bpf_test_run_opts, topts, + .data_in = &pkt_v4, + .data_size_in = sizeof(pkt_v4), + .repeat = 1, + ); + + skel = type_cast__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + bpf_program__set_autoload(skel->progs.md_skb, true); + err = type_cast__load(skel); + if (!ASSERT_OK(err, "skel_load")) + goto out; + + prog_fd = bpf_program__fd(skel->progs.md_skb); + err = bpf_prog_test_run_opts(prog_fd, &topts); + ASSERT_OK(err, "test_run"); + ASSERT_EQ(topts.retval, 0, "tc test_run retval"); + + ASSERT_EQ(skel->bss->meta_len, 0, "skb meta_len"); + ASSERT_EQ(skel->bss->frag0_len, 0, "skb frag0_len"); + ASSERT_NEQ(skel->bss->kskb_len, 0, "skb len"); + ASSERT_NEQ(skel->bss->kskb2_len, 0, "skb2 len"); + ASSERT_EQ(skel->bss->kskb_len, skel->bss->kskb2_len, "skb len compare"); + +out: + type_cast__destroy(skel); +} + +static const char * const negative_tests[] = { + "untrusted_ptr", + "kctx_u64", +}; + +static void test_negative(void) +{ + struct bpf_program *prog; + struct type_cast *skel; + int i, err; + + for (i = 0; i < ARRAY_SIZE(negative_tests); i++) { + skel = type_cast__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + prog = bpf_object__find_program_by_name(skel->obj, negative_tests[i]); + if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name")) + goto out; + bpf_program__set_autoload(prog, true); + err = type_cast__load(skel); + ASSERT_ERR(err, "skel_load"); +out: + type_cast__destroy(skel); + } +} + +void test_type_cast(void) +{ + if (test__start_subtest("xdp")) + test_xdp(); + if (test__start_subtest("tc")) + test_tc(); + if (test__start_subtest("negative")) + test_negative(); +} diff --git a/tools/testing/selftests/bpf/progs/type_cast.c b/tools/testing/selftests/bpf/progs/type_cast.c new file mode 100644 index 000000000000..eb78e6f03129 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/type_cast.c @@ -0,0 +1,83 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ +#include "vmlinux.h" +#include +#include +#include + +struct { + __uint(type, BPF_MAP_TYPE_TASK_STORAGE); + __uint(map_flags, BPF_F_NO_PREALLOC); + __type(key, int); + __type(value, long); +} enter_id SEC(".maps"); + +#define IFNAMSIZ 16 + +int ifindex, ingress_ifindex; +char name[IFNAMSIZ]; +unsigned int inum; +unsigned int meta_len, frag0_len, kskb_len, kskb2_len; + +void *bpf_cast_to_kern_ctx(void *) __ksym; +void *bpf_rdonly_cast(void *, __u32) __ksym; + +SEC("?xdp") +int md_xdp(struct xdp_md *ctx) +{ + struct xdp_buff *kctx = bpf_cast_to_kern_ctx(ctx); + struct net_device *dev; + + dev = kctx->rxq->dev; + ifindex = dev->ifindex; + inum = dev->nd_net.net->ns.inum; + __builtin_memcpy(name, dev->name, IFNAMSIZ); + ingress_ifindex = ctx->ingress_ifindex; + return XDP_PASS; +} + +SEC("?tc") +int md_skb(struct __sk_buff *skb) +{ + struct sk_buff *kskb = bpf_cast_to_kern_ctx(skb); + struct skb_shared_info *shared_info; + struct sk_buff *kskb2; + + kskb_len = kskb->len; + + /* Simulate the following kernel macro: + * #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB))) + */ + shared_info = bpf_rdonly_cast(kskb->head + kskb->end, + bpf_core_type_id_kernel(struct skb_shared_info)); + meta_len = shared_info->meta_len; + frag0_len = shared_info->frag_list->len; + + /* kskb2 should be equal to kskb */ + kskb2 = bpf_rdonly_cast(kskb, bpf_core_type_id_kernel(struct sk_buff)); + kskb2_len = kskb2->len; + return 0; +} + +SEC("?tp_btf/sys_enter") +int BPF_PROG(untrusted_ptr, struct pt_regs *regs, long id) +{ + struct task_struct *task, *task_dup; + long *ptr; + + task = bpf_get_current_task_btf(); + task_dup = bpf_rdonly_cast(task, bpf_core_type_id_kernel(struct task_struct)); + (void)bpf_task_storage_get(&enter_id, task_dup, 0, 0); + return 0; +} + +SEC("?tracepoint/syscalls/sys_enter_nanosleep") +int kctx_u64(void *ctx) +{ + u64 *kctx = bpf_rdonly_cast(ctx, bpf_core_type_id_kernel(u64)); + + (void)kctx; + return 0; +} + +char _license[] SEC("license") = "GPL"; From 9b8107553424fd87955fed257a807672c2097297 Mon Sep 17 00:00:00 2001 From: Sahid Orentino Ferdjaoui Date: Sun, 20 Nov 2022 11:25:55 +0000 Subject: [PATCH 063/101] bpftool: remove support of --legacy option for bpftool Following: commit bd054102a8c7 ("libbpf: enforce strict libbpf 1.0 behaviors") commit 93b8952d223a ("libbpf: deprecate legacy BPF map definitions") The --legacy option is no longer relevant as libbpf no longer supports it. libbpf_set_strict_mode() is a no-op operation. Signed-off-by: Sahid Orentino Ferdjaoui Acked-by: Yonghong Song Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/r/20221120112515.38165-2-sahid.ferdjaoui@industrialdiscipline.com Signed-off-by: Alexei Starovoitov --- .../bpf/bpftool/Documentation/common_options.rst | 9 --------- tools/bpf/bpftool/Documentation/substitutions.rst | 2 +- tools/bpf/bpftool/bash-completion/bpftool | 2 +- tools/bpf/bpftool/main.c | 15 --------------- tools/bpf/bpftool/main.h | 3 +-- tools/bpf/bpftool/prog.c | 5 ----- .../selftests/bpf/test_bpftool_synctypes.py | 6 +++--- 7 files changed, 6 insertions(+), 36 deletions(-) diff --git a/tools/bpf/bpftool/Documentation/common_options.rst b/tools/bpf/bpftool/Documentation/common_options.rst index 05350a1aadf9..30df7a707f02 100644 --- a/tools/bpf/bpftool/Documentation/common_options.rst +++ b/tools/bpf/bpftool/Documentation/common_options.rst @@ -23,12 +23,3 @@ Print all logs available, even debug-level information. This includes logs from libbpf as well as from the verifier, when attempting to load programs. - --l, --legacy - Use legacy libbpf mode which has more relaxed BPF program - requirements. By default, bpftool has more strict requirements - about section names, changes pinning logic and doesn't support - some of the older non-BTF map declarations. - - See https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0 - for details. diff --git a/tools/bpf/bpftool/Documentation/substitutions.rst b/tools/bpf/bpftool/Documentation/substitutions.rst index ccf1ffa0686c..827e3ffb1766 100644 --- a/tools/bpf/bpftool/Documentation/substitutions.rst +++ b/tools/bpf/bpftool/Documentation/substitutions.rst @@ -1,3 +1,3 @@ .. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) -.. |COMMON_OPTIONS| replace:: { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-d** | **--debug** } | { **-l** | **--legacy** } +.. |COMMON_OPTIONS| replace:: { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-d** | **--debug** } diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool index 2957b42cab67..35f26f7c1124 100644 --- a/tools/bpf/bpftool/bash-completion/bpftool +++ b/tools/bpf/bpftool/bash-completion/bpftool @@ -261,7 +261,7 @@ _bpftool() # Deal with options if [[ ${words[cword]} == -* ]]; then local c='--version --json --pretty --bpffs --mapcompat --debug \ - --use-loader --base-btf --legacy' + --use-loader --base-btf' COMPREPLY=( $( compgen -W "$c" -- "$cur" ) ) return 0 fi diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c index 337ab7977ea4..c53c553adcac 100644 --- a/tools/bpf/bpftool/main.c +++ b/tools/bpf/bpftool/main.c @@ -31,7 +31,6 @@ bool block_mount; bool verifier_logs; bool relaxed_maps; bool use_loader; -bool legacy_libbpf; struct btf *base_btf; struct hashmap *refs_table; @@ -160,7 +159,6 @@ static int do_version(int argc, char **argv) jsonw_start_object(json_wtr); /* features */ jsonw_bool_field(json_wtr, "libbfd", has_libbfd); jsonw_bool_field(json_wtr, "llvm", has_llvm); - jsonw_bool_field(json_wtr, "libbpf_strict", !legacy_libbpf); jsonw_bool_field(json_wtr, "skeletons", has_skeletons); jsonw_bool_field(json_wtr, "bootstrap", bootstrap); jsonw_end_object(json_wtr); /* features */ @@ -179,7 +177,6 @@ static int do_version(int argc, char **argv) printf("features:"); print_feature("libbfd", has_libbfd, &nb_features); print_feature("llvm", has_llvm, &nb_features); - print_feature("libbpf_strict", !legacy_libbpf, &nb_features); print_feature("skeletons", has_skeletons, &nb_features); print_feature("bootstrap", bootstrap, &nb_features); printf("\n"); @@ -451,7 +448,6 @@ int main(int argc, char **argv) { "debug", no_argument, NULL, 'd' }, { "use-loader", no_argument, NULL, 'L' }, { "base-btf", required_argument, NULL, 'B' }, - { "legacy", no_argument, NULL, 'l' }, { 0 } }; bool version_requested = false; @@ -524,9 +520,6 @@ int main(int argc, char **argv) case 'L': use_loader = true; break; - case 'l': - legacy_libbpf = true; - break; default: p_err("unrecognized option '%s'", argv[optind - 1]); if (json_output) @@ -536,14 +529,6 @@ int main(int argc, char **argv) } } - if (!legacy_libbpf) { - /* Allow legacy map definitions for skeleton generation. - * It will still be rejected if users use LIBBPF_STRICT_ALL - * mode for loading generated skeleton. - */ - libbpf_set_strict_mode(LIBBPF_STRICT_ALL & ~LIBBPF_STRICT_MAP_DEFINITIONS); - } - argc -= optind; argv += optind; if (argc < 0) diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h index d4e8a1aef787..a84224b6a604 100644 --- a/tools/bpf/bpftool/main.h +++ b/tools/bpf/bpftool/main.h @@ -57,7 +57,7 @@ static inline void *u64_to_ptr(__u64 ptr) #define HELP_SPEC_PROGRAM \ "PROG := { id PROG_ID | pinned FILE | tag PROG_TAG | name PROG_NAME }" #define HELP_SPEC_OPTIONS \ - "OPTIONS := { {-j|--json} [{-p|--pretty}] | {-d|--debug} | {-l|--legacy}" + "OPTIONS := { {-j|--json} [{-p|--pretty}] | {-d|--debug}" #define HELP_SPEC_MAP \ "MAP := { id MAP_ID | pinned FILE | name MAP_NAME }" #define HELP_SPEC_LINK \ @@ -82,7 +82,6 @@ extern bool block_mount; extern bool verifier_logs; extern bool relaxed_maps; extern bool use_loader; -extern bool legacy_libbpf; extern struct btf *base_btf; extern struct hashmap *refs_table; diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c index 9d32ffb9f22e..2266958f203f 100644 --- a/tools/bpf/bpftool/prog.c +++ b/tools/bpf/bpftool/prog.c @@ -1802,11 +1802,6 @@ err_unpin: else bpf_object__unpin_programs(obj, pinfile); err_close_obj: - if (!legacy_libbpf) { - p_info("Warning: bpftool is now running in libbpf strict mode and has more stringent requirements about BPF programs.\n" - "If it used to work for this object file but now doesn't, see --legacy option for more details.\n"); - } - bpf_object__close(obj); err_free_reuse_maps: for (i = 0; i < old_map_fds; i++) diff --git a/tools/testing/selftests/bpf/test_bpftool_synctypes.py b/tools/testing/selftests/bpf/test_bpftool_synctypes.py index 9fe4c9336c6f..0cfece7ff4f8 100755 --- a/tools/testing/selftests/bpf/test_bpftool_synctypes.py +++ b/tools/testing/selftests/bpf/test_bpftool_synctypes.py @@ -309,11 +309,11 @@ class MainHeaderFileExtractor(SourceFileExtractor): commands), which looks to the lists of options in other source files but has different start and end markers: - "OPTIONS := { {-j|--json} [{-p|--pretty}] | {-d|--debug} | {-l|--legacy}" + "OPTIONS := { {-j|--json} [{-p|--pretty}] | {-d|--debug}" Return a set containing all options, such as: - {'-p', '-d', '--legacy', '--pretty', '--debug', '--json', '-l', '-j'} + {'-p', '-d', '--pretty', '--debug', '--json', '-j'} """ start_marker = re.compile(f'"OPTIONS :=') pattern = re.compile('([\w-]+) ?(?:\||}[ }\]"])') @@ -336,7 +336,7 @@ class ManSubstitutionsExtractor(SourceFileExtractor): Return a set containing all options, such as: - {'-p', '-d', '--legacy', '--pretty', '--debug', '--json', '-l', '-j'} + {'-p', '-d', '--pretty', '--debug', '--json', '-j'} """ start_marker = re.compile('\|COMMON_OPTIONS\| replace:: {') pattern = re.compile('\*\*([\w/-]+)\*\*') From 989f285159b84831c54d277112dcf803da51e722 Mon Sep 17 00:00:00 2001 From: Sahid Orentino Ferdjaoui Date: Sun, 20 Nov 2022 11:26:07 +0000 Subject: [PATCH 064/101] bpftool: replace return value PTR_ERR(NULL) with 0 There is no reasons to keep PTR_ERR() when kern_btf=NULL, let's just return 0. This also cleans this part of code from using libbpf_get_error(). Signed-off-by: Sahid Orentino Ferdjaoui Acked-by: Yonghong Song Suggested-by: Quentin Monnet Link: https://lore.kernel.org/r/20221120112515.38165-3-sahid.ferdjaoui@industrialdiscipline.com Signed-off-by: Alexei Starovoitov --- tools/bpf/bpftool/struct_ops.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/tools/bpf/bpftool/struct_ops.c b/tools/bpf/bpftool/struct_ops.c index e08a6ff2866c..d3cfdfef9b58 100644 --- a/tools/bpf/bpftool/struct_ops.c +++ b/tools/bpf/bpftool/struct_ops.c @@ -63,10 +63,8 @@ static __s32 get_map_info_type_id(void) return map_info_type_id; kern_btf = get_btf_vmlinux(); - if (libbpf_get_error(kern_btf)) { - map_info_type_id = PTR_ERR(kern_btf); - return map_info_type_id; - } + if (!kern_btf) + return 0; map_info_type_id = btf__find_by_name_kind(kern_btf, "bpf_map_info", BTF_KIND_STRUCT); From d2973ffd25c2295055349212ca26c18929e5e9f5 Mon Sep 17 00:00:00 2001 From: Sahid Orentino Ferdjaoui Date: Sun, 20 Nov 2022 11:26:18 +0000 Subject: [PATCH 065/101] bpftool: fix error message when function can't register struct_ops It is expected that errno be passed to strerror(). This also cleans this part of code from using libbpf_get_error(). Signed-off-by: Sahid Orentino Ferdjaoui Acked-by: Yonghong Song Suggested-by: Quentin Monnet Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/r/20221120112515.38165-4-sahid.ferdjaoui@industrialdiscipline.com Signed-off-by: Alexei Starovoitov --- tools/bpf/bpftool/struct_ops.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/tools/bpf/bpftool/struct_ops.c b/tools/bpf/bpftool/struct_ops.c index d3cfdfef9b58..ae9ad85f5cda 100644 --- a/tools/bpf/bpftool/struct_ops.c +++ b/tools/bpf/bpftool/struct_ops.c @@ -511,10 +511,9 @@ static int do_register(int argc, char **argv) continue; link = bpf_map__attach_struct_ops(map); - if (libbpf_get_error(link)) { + if (!link) { p_err("can't register struct_ops %s: %s", - bpf_map__name(map), - strerror(-PTR_ERR(link))); + bpf_map__name(map), strerror(errno)); nr_errs++; continue; } From d1313e01271d2d8f33d6c82f1afb77e820a3540d Mon Sep 17 00:00:00 2001 From: Sahid Orentino Ferdjaoui Date: Sun, 20 Nov 2022 11:26:32 +0000 Subject: [PATCH 066/101] bpftool: clean-up usage of libbpf_get_error() bpftool is now totally compliant with libbpf 1.0 mode and is not expected to be compiled with pre-1.0, let's clean-up the usage of libbpf_get_error(). The changes stay aligned with returned errors always negative. - In tools/bpf/bpftool/btf.c This fixes an uninitialized local variable `err` in function do_dump() because it may now be returned without having been set. - This also removes the checks on NULL pointers before calling btf__free() because that function already does the check. Signed-off-by: Sahid Orentino Ferdjaoui Link: https://lore.kernel.org/r/20221120112515.38165-5-sahid.ferdjaoui@industrialdiscipline.com Signed-off-by: Alexei Starovoitov --- tools/bpf/bpftool/btf.c | 19 ++++++++----------- tools/bpf/bpftool/btf_dumper.c | 2 +- tools/bpf/bpftool/gen.c | 10 ++++------ tools/bpf/bpftool/iter.c | 10 ++++++---- tools/bpf/bpftool/main.c | 7 +++---- tools/bpf/bpftool/map.c | 15 +++++++-------- tools/bpf/bpftool/prog.c | 10 +++++----- tools/bpf/bpftool/struct_ops.c | 11 +++++------ 8 files changed, 39 insertions(+), 45 deletions(-) diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c index b87e4a7fd689..352290ba7b29 100644 --- a/tools/bpf/bpftool/btf.c +++ b/tools/bpf/bpftool/btf.c @@ -467,9 +467,8 @@ static int dump_btf_c(const struct btf *btf, int err = 0, i; d = btf_dump__new(btf, btf_dump_printf, NULL, NULL); - err = libbpf_get_error(d); - if (err) - return err; + if (!d) + return -errno; printf("#ifndef __VMLINUX_H__\n"); printf("#define __VMLINUX_H__\n"); @@ -512,11 +511,9 @@ static struct btf *get_vmlinux_btf_from_sysfs(void) struct btf *base; base = btf__parse(sysfs_vmlinux, NULL); - if (libbpf_get_error(base)) { - p_err("failed to parse vmlinux BTF at '%s': %ld\n", - sysfs_vmlinux, libbpf_get_error(base)); - base = NULL; - } + if (!base) + p_err("failed to parse vmlinux BTF at '%s': %d\n", + sysfs_vmlinux, -errno); return base; } @@ -559,7 +556,7 @@ static int do_dump(int argc, char **argv) __u32 btf_id = -1; const char *src; int fd = -1; - int err; + int err = 0; if (!REQ_ARGS(2)) { usage(); @@ -634,8 +631,8 @@ static int do_dump(int argc, char **argv) base = get_vmlinux_btf_from_sysfs(); btf = btf__parse_split(*argv, base ?: base_btf); - err = libbpf_get_error(btf); if (!btf) { + err = -errno; p_err("failed to load BTF from %s: %s", *argv, strerror(errno)); goto done; @@ -681,8 +678,8 @@ static int do_dump(int argc, char **argv) } btf = btf__load_from_kernel_by_id_split(btf_id, base_btf); - err = libbpf_get_error(btf); if (!btf) { + err = -errno; p_err("get btf by id (%u): %s", btf_id, strerror(errno)); goto done; } diff --git a/tools/bpf/bpftool/btf_dumper.c b/tools/bpf/bpftool/btf_dumper.c index 19924b6ce796..eda71fdfe95a 100644 --- a/tools/bpf/bpftool/btf_dumper.c +++ b/tools/bpf/bpftool/btf_dumper.c @@ -75,7 +75,7 @@ static int dump_prog_id_as_func_ptr(const struct btf_dumper *d, goto print; prog_btf = btf__load_from_kernel_by_id(info.btf_id); - if (libbpf_get_error(prog_btf)) + if (!prog_btf) goto print; func_type = btf__type_by_id(prog_btf, finfo.type_id); if (!func_type || !btf_is_func(func_type)) diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c index 01bb8d8f5568..2883660d6b67 100644 --- a/tools/bpf/bpftool/gen.c +++ b/tools/bpf/bpftool/gen.c @@ -252,9 +252,8 @@ static int codegen_datasecs(struct bpf_object *obj, const char *obj_name) int err = 0; d = btf_dump__new(btf, codegen_btf_dump_printf, NULL, NULL); - err = libbpf_get_error(d); - if (err) - return err; + if (!d) + return -errno; bpf_object__for_each_map(map, obj) { /* only generate definitions for memory-mapped internal maps */ @@ -976,13 +975,12 @@ static int do_skeleton(int argc, char **argv) /* log_level1 + log_level2 + stats, but not stable UAPI */ opts.kernel_log_level = 1 + 2 + 4; obj = bpf_object__open_mem(obj_data, file_sz, &opts); - err = libbpf_get_error(obj); - if (err) { + if (!obj) { char err_buf[256]; + err = -errno; libbpf_strerror(err, err_buf, sizeof(err_buf)); p_err("failed to open BPF object file: %s", err_buf); - obj = NULL; goto out; } diff --git a/tools/bpf/bpftool/iter.c b/tools/bpf/bpftool/iter.c index a3e6b167153d..9a1d2365a297 100644 --- a/tools/bpf/bpftool/iter.c +++ b/tools/bpf/bpftool/iter.c @@ -4,6 +4,7 @@ #ifndef _GNU_SOURCE #define _GNU_SOURCE #endif +#include #include #include #include @@ -48,8 +49,8 @@ static int do_pin(int argc, char **argv) } obj = bpf_object__open(objfile); - err = libbpf_get_error(obj); - if (err) { + if (!obj) { + err = -errno; p_err("can't open objfile %s", objfile); goto close_map_fd; } @@ -62,13 +63,14 @@ static int do_pin(int argc, char **argv) prog = bpf_object__next_program(obj, NULL); if (!prog) { + err = -errno; p_err("can't find bpf program in objfile %s", objfile); goto close_obj; } link = bpf_program__attach_iter(prog, &iter_opts); - err = libbpf_get_error(link); - if (err) { + if (!link) { + err = -errno; p_err("attach_iter failed for program %s", bpf_program__name(prog)); goto close_obj; diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c index c53c553adcac..08d0ac543c67 100644 --- a/tools/bpf/bpftool/main.c +++ b/tools/bpf/bpftool/main.c @@ -510,10 +510,9 @@ int main(int argc, char **argv) break; case 'B': base_btf = btf__parse(optarg, NULL); - if (libbpf_get_error(base_btf)) { - p_err("failed to parse base BTF at '%s': %ld\n", - optarg, libbpf_get_error(base_btf)); - base_btf = NULL; + if (!base_btf) { + p_err("failed to parse base BTF at '%s': %d\n", + optarg, -errno); return -1; } break; diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c index d884070a2314..eb362bd3d2c9 100644 --- a/tools/bpf/bpftool/map.c +++ b/tools/bpf/bpftool/map.c @@ -786,18 +786,18 @@ static int get_map_kv_btf(const struct bpf_map_info *info, struct btf **btf) if (info->btf_vmlinux_value_type_id) { if (!btf_vmlinux) { btf_vmlinux = libbpf_find_kernel_btf(); - err = libbpf_get_error(btf_vmlinux); - if (err) { + if (!btf_vmlinux) { p_err("failed to get kernel btf"); - return err; + return -errno; } } *btf = btf_vmlinux; } else if (info->btf_value_type_id) { *btf = btf__load_from_kernel_by_id(info->btf_id); - err = libbpf_get_error(*btf); - if (err) + if (!*btf) { + err = -errno; p_err("failed to get btf"); + } } else { *btf = NULL; } @@ -807,14 +807,13 @@ static int get_map_kv_btf(const struct bpf_map_info *info, struct btf **btf) static void free_map_kv_btf(struct btf *btf) { - if (!libbpf_get_error(btf) && btf != btf_vmlinux) + if (btf != btf_vmlinux) btf__free(btf); } static void free_btf_vmlinux(void) { - if (!libbpf_get_error(btf_vmlinux)) - btf__free(btf_vmlinux); + btf__free(btf_vmlinux); } static int diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c index 2266958f203f..cfc9fdc1e863 100644 --- a/tools/bpf/bpftool/prog.c +++ b/tools/bpf/bpftool/prog.c @@ -322,7 +322,7 @@ static void show_prog_metadata(int fd, __u32 num_maps) return; btf = btf__load_from_kernel_by_id(map_info.btf_id); - if (libbpf_get_error(btf)) + if (!btf) goto out_free; t_datasec = btf__type_by_id(btf, map_info.btf_value_type_id); @@ -726,7 +726,7 @@ prog_dump(struct bpf_prog_info *info, enum dump_mode mode, if (info->btf_id) { btf = btf__load_from_kernel_by_id(info->btf_id); - if (libbpf_get_error(btf)) { + if (!btf) { p_err("failed to get btf"); return -1; } @@ -1663,7 +1663,7 @@ static int load_with_options(int argc, char **argv, bool first_prog_only) open_opts.kernel_log_level = 1 + 2 + 4; obj = bpf_object__open_file(file, &open_opts); - if (libbpf_get_error(obj)) { + if (!obj) { p_err("failed to open object file"); goto err_free_reuse_maps; } @@ -1882,7 +1882,7 @@ static int do_loader(int argc, char **argv) open_opts.kernel_log_level = 1 + 2 + 4; obj = bpf_object__open_file(file, &open_opts); - if (libbpf_get_error(obj)) { + if (!obj) { p_err("failed to open object file"); goto err_close_obj; } @@ -2199,7 +2199,7 @@ static char *profile_target_name(int tgt_fd) } btf = btf__load_from_kernel_by_id(info.btf_id); - if (libbpf_get_error(btf)) { + if (!btf) { p_err("failed to load btf for prog FD %d", tgt_fd); goto out; } diff --git a/tools/bpf/bpftool/struct_ops.c b/tools/bpf/bpftool/struct_ops.c index ae9ad85f5cda..903b80ff4e9a 100644 --- a/tools/bpf/bpftool/struct_ops.c +++ b/tools/bpf/bpftool/struct_ops.c @@ -32,7 +32,7 @@ static const struct btf *get_btf_vmlinux(void) return btf_vmlinux; btf_vmlinux = libbpf_find_kernel_btf(); - if (libbpf_get_error(btf_vmlinux)) + if (!btf_vmlinux) p_err("struct_ops requires kernel CONFIG_DEBUG_INFO_BTF=y"); return btf_vmlinux; @@ -45,7 +45,7 @@ static const char *get_kern_struct_ops_name(const struct bpf_map_info *info) const char *st_ops_name; kern_btf = get_btf_vmlinux(); - if (libbpf_get_error(kern_btf)) + if (!kern_btf) return ""; t = btf__type_by_id(kern_btf, info->btf_vmlinux_value_type_id); @@ -413,7 +413,7 @@ static int do_dump(int argc, char **argv) } kern_btf = get_btf_vmlinux(); - if (libbpf_get_error(kern_btf)) + if (!kern_btf) return -1; if (!json_output) { @@ -496,7 +496,7 @@ static int do_register(int argc, char **argv) open_opts.kernel_log_level = 1 + 2 + 4; obj = bpf_object__open_file(file, &open_opts); - if (libbpf_get_error(obj)) + if (!obj) return -1; set_max_rlimit(); @@ -590,8 +590,7 @@ int do_struct_ops(int argc, char **argv) err = cmd_select(cmds, argc, argv, do_help); - if (!libbpf_get_error(btf_vmlinux)) - btf__free(btf_vmlinux); + btf__free(btf_vmlinux); return err; } From 52df1a8aabadeba1e4c2fe157784637ddec76301 Mon Sep 17 00:00:00 2001 From: Sahid Orentino Ferdjaoui Date: Sun, 20 Nov 2022 11:26:43 +0000 Subject: [PATCH 067/101] bpftool: remove function free_btf_vmlinux() The function contains a single btf__free() call which can be inlined. Credits to Yonghong Song. Signed-off-by: Sahid Orentino Ferdjaoui Acked-by: Yonghong Song Suggested-by: Yonghong Song Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/r/20221120112515.38165-6-sahid.ferdjaoui@industrialdiscipline.com Signed-off-by: Alexei Starovoitov --- tools/bpf/bpftool/map.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c index eb362bd3d2c9..88911d3aa2d9 100644 --- a/tools/bpf/bpftool/map.c +++ b/tools/bpf/bpftool/map.c @@ -811,11 +811,6 @@ static void free_map_kv_btf(struct btf *btf) btf__free(btf); } -static void free_btf_vmlinux(void) -{ - btf__free(btf_vmlinux); -} - static int map_dump(int fd, struct bpf_map_info *info, json_writer_t *wtr, bool show_header) @@ -952,7 +947,7 @@ exit_close: close(fds[i]); exit_free: free(fds); - free_btf_vmlinux(); + btf__free(btf_vmlinux); return err; } From ceb35b666d42c2e91b1f94aeca95bb5eb0943268 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 18 Nov 2022 10:34:14 -0800 Subject: [PATCH 068/101] bpf/verifier: Use kmalloc_size_roundup() to match ksize() usage Most allocation sites in the kernel want an explicitly sized allocation (and not "more"), and that dynamic runtime analysis tools (e.g. KASAN, UBSAN_BOUNDS, FORTIFY_SOURCE, etc) are looking for precise bounds checking (i.e. not something that is rounded up). A tiny handful of allocations were doing an implicit alloc/realloc loop that actually depended on ksize(), and didn't actually always call realloc. This has created a long series of bugs and problems over many years related to the runtime bounds checking, so these callers are finally being adjusted to _not_ depend on the ksize() side-effect, by doing one of several things: - tracking the allocation size precisely and just never calling ksize() at all [1]. - always calling realloc and not using ksize() at all. (This solution ends up actually be a subset of the next solution.) - using kmalloc_size_roundup() to explicitly round up the desired allocation size immediately [2]. The bpf/verifier case is this another of this latter case, and is the last outstanding case to be fixed in the kernel. Because some of the dynamic bounds checking depends on the size being an _argument_ to an allocator function (i.e. see the __alloc_size attribute), the ksize() users are rare, and it could waste local variables, it was been deemed better to explicitly separate the rounding up from the allocation itself [3]. Round up allocations with kmalloc_size_roundup() so that the verifier's use of ksize() is always accurate. [1] e.g.: https://git.kernel.org/linus/712f210a457d https://git.kernel.org/linus/72c08d9f4c72 [2] e.g.: https://git.kernel.org/netdev/net-next/c/12d6c1d3a2ad https://git.kernel.org/netdev/net-next/c/ab3f7828c979 https://git.kernel.org/netdev/net-next/c/d6dd508080a3 [3] https://lore.kernel.org/lkml/0ea1fc165a6c6117f982f4f135093e69cb884930.camel@redhat.com/ Signed-off-by: Kees Cook Signed-off-by: Daniel Borkmann Acked-by: Stanislav Fomichev Link: https://lore.kernel.org/bpf/20221118183409.give.387-kees@kernel.org --- kernel/bpf/verifier.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index f07bec227fef..9528a066cfa5 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1022,9 +1022,9 @@ static void *copy_array(void *dst, const void *src, size_t n, size_t size, gfp_t if (unlikely(check_mul_overflow(n, size, &bytes))) return NULL; - if (ksize(dst) < bytes) { + if (ksize(dst) < ksize(src)) { kfree(dst); - dst = kmalloc_track_caller(bytes, flags); + dst = kmalloc_track_caller(kmalloc_size_roundup(bytes), flags); if (!dst) return NULL; } @@ -1041,12 +1041,14 @@ out: */ static void *realloc_array(void *arr, size_t old_n, size_t new_n, size_t size) { + size_t alloc_size; void *new_arr; if (!new_n || old_n == new_n) goto out; - new_arr = krealloc_array(arr, new_n, size, GFP_KERNEL); + alloc_size = kmalloc_size_roundup(size_mul(new_n, size)); + new_arr = krealloc(arr, alloc_size, GFP_KERNEL); if (!new_arr) { kfree(arr); return NULL; @@ -2519,9 +2521,11 @@ static int push_jmp_history(struct bpf_verifier_env *env, { u32 cnt = cur->jmp_history_cnt; struct bpf_idx_pair *p; + size_t alloc_size; cnt++; - p = krealloc(cur->jmp_history, cnt * sizeof(*p), GFP_USER); + alloc_size = kmalloc_size_roundup(size_mul(cnt, sizeof(*p))); + p = krealloc(cur->jmp_history, alloc_size, GFP_USER); if (!p) return -ENOMEM; p[cnt - 1].idx = env->insn_idx; From 1a5160d4d8fe63ba4964cfff4a85831b6af75f2d Mon Sep 17 00:00:00 2001 From: Hou Tao Date: Mon, 21 Nov 2022 15:34:38 +0800 Subject: [PATCH 069/101] bpf: Pin the start cgroup in cgroup_iter_seq_init() bpf_iter_attach_cgroup() has already acquired an extra reference for the start cgroup, but the reference may be released if the iterator link fd is closed after the creation of iterator fd, and it may lead to user-after-free problem when reading the iterator fd. An alternative fix is pinning iterator link when opening iterator, but it will make iterator link being still visible after the close of iterator link fd and the behavior is different with other link types, so just fixing it by acquiring another reference for the start cgroup. Fixes: d4ccaf58a847 ("bpf: Introduce cgroup iter") Signed-off-by: Hou Tao Signed-off-by: Daniel Borkmann Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20221121073440.1828292-2-houtao@huaweicloud.com --- kernel/bpf/cgroup_iter.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/kernel/bpf/cgroup_iter.c b/kernel/bpf/cgroup_iter.c index fbc6167c3599..06989d278846 100644 --- a/kernel/bpf/cgroup_iter.c +++ b/kernel/bpf/cgroup_iter.c @@ -164,16 +164,30 @@ static int cgroup_iter_seq_init(void *priv, struct bpf_iter_aux_info *aux) struct cgroup_iter_priv *p = (struct cgroup_iter_priv *)priv; struct cgroup *cgrp = aux->cgroup.start; + /* bpf_iter_attach_cgroup() has already acquired an extra reference + * for the start cgroup, but the reference may be released after + * cgroup_iter_seq_init(), so acquire another reference for the + * start cgroup. + */ p->start_css = &cgrp->self; + css_get(p->start_css); p->terminate = false; p->visited_all = false; p->order = aux->cgroup.order; return 0; } +static void cgroup_iter_seq_fini(void *priv) +{ + struct cgroup_iter_priv *p = (struct cgroup_iter_priv *)priv; + + css_put(p->start_css); +} + static const struct bpf_iter_seq_info cgroup_iter_seq_info = { .seq_ops = &cgroup_iter_seq_ops, .init_seq_private = cgroup_iter_seq_init, + .fini_seq_private = cgroup_iter_seq_fini, .seq_priv_size = sizeof(struct cgroup_iter_priv), }; From 2a42461a88314bbeaa3dcad3d19a4bb3d9aa546f Mon Sep 17 00:00:00 2001 From: Hou Tao Date: Mon, 21 Nov 2022 15:34:39 +0800 Subject: [PATCH 070/101] selftests/bpf: Add cgroup helper remove_cgroup() Add remove_cgroup() to remove a cgroup which doesn't have any children or live processes. It will be used by the following patch to test cgroup iterator on a dead cgroup. Signed-off-by: Hou Tao Signed-off-by: Daniel Borkmann Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20221121073440.1828292-3-houtao@huaweicloud.com --- tools/testing/selftests/bpf/cgroup_helpers.c | 19 +++++++++++++++++++ tools/testing/selftests/bpf/cgroup_helpers.h | 1 + 2 files changed, 20 insertions(+) diff --git a/tools/testing/selftests/bpf/cgroup_helpers.c b/tools/testing/selftests/bpf/cgroup_helpers.c index dd1aa5afcf5a..9e95b37a7dff 100644 --- a/tools/testing/selftests/bpf/cgroup_helpers.c +++ b/tools/testing/selftests/bpf/cgroup_helpers.c @@ -333,6 +333,25 @@ int get_root_cgroup(void) return fd; } +/* + * remove_cgroup() - Remove a cgroup + * @relative_path: The cgroup path, relative to the workdir, to remove + * + * This function expects a cgroup to already be created, relative to the cgroup + * work dir. It also expects the cgroup doesn't have any children or live + * processes and it removes the cgroup. + * + * On failure, it will print an error to stderr. + */ +void remove_cgroup(const char *relative_path) +{ + char cgroup_path[PATH_MAX + 1]; + + format_cgroup_path(cgroup_path, relative_path); + if (rmdir(cgroup_path)) + log_err("rmdiring cgroup %s .. %s", relative_path, cgroup_path); +} + /** * create_and_get_cgroup() - Create a cgroup, relative to workdir, and get the FD * @relative_path: The cgroup path, relative to the workdir, to join diff --git a/tools/testing/selftests/bpf/cgroup_helpers.h b/tools/testing/selftests/bpf/cgroup_helpers.h index 3358734356ab..f099a166c94d 100644 --- a/tools/testing/selftests/bpf/cgroup_helpers.h +++ b/tools/testing/selftests/bpf/cgroup_helpers.h @@ -18,6 +18,7 @@ int write_cgroup_file_parent(const char *relative_path, const char *file, int cgroup_setup_and_join(const char *relative_path); int get_root_cgroup(void); int create_and_get_cgroup(const char *relative_path); +void remove_cgroup(const char *relative_path); unsigned long long get_cgroup_id(const char *relative_path); int join_cgroup(const char *relative_path); From 8589e92675aa4727bede3f9230709624619844f3 Mon Sep 17 00:00:00 2001 From: Hou Tao Date: Mon, 21 Nov 2022 15:34:40 +0800 Subject: [PATCH 071/101] selftests/bpf: Add test for cgroup iterator on a dead cgroup The test closes both iterator link fd and cgroup fd, and removes the cgroup file to make a dead cgroup before reading from cgroup iterator. It also uses kern_sync_rcu() and usleep() to wait for the release of start cgroup. If the start cgroup is not pinned by cgroup iterator, reading from iterator fd will trigger use-after-free. Signed-off-by: Hou Tao Signed-off-by: Daniel Borkmann Acked-by: Yonghong Song Acked-by: Hao Luo Link: https://lore.kernel.org/bpf/20221121073440.1828292-4-houtao@huaweicloud.com --- .../selftests/bpf/prog_tests/cgroup_iter.c | 76 +++++++++++++++++++ 1 file changed, 76 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_iter.c b/tools/testing/selftests/bpf/prog_tests/cgroup_iter.c index c4a2adb38da1..e02feb5fae97 100644 --- a/tools/testing/selftests/bpf/prog_tests/cgroup_iter.c +++ b/tools/testing/selftests/bpf/prog_tests/cgroup_iter.c @@ -189,6 +189,80 @@ static void test_walk_self_only(struct cgroup_iter *skel) BPF_CGROUP_ITER_SELF_ONLY, "self_only"); } +static void test_walk_dead_self_only(struct cgroup_iter *skel) +{ + DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts); + char expected_output[128], buf[128]; + const char *cgrp_name = "/dead"; + union bpf_iter_link_info linfo; + int len, cgrp_fd, iter_fd; + struct bpf_link *link; + size_t left; + char *p; + + cgrp_fd = create_and_get_cgroup(cgrp_name); + if (!ASSERT_GE(cgrp_fd, 0, "create cgrp")) + return; + + /* The cgroup will be dead during read() iteration, so it only has + * epilogue in the output + */ + snprintf(expected_output, sizeof(expected_output), EPILOGUE); + + memset(&linfo, 0, sizeof(linfo)); + linfo.cgroup.cgroup_fd = cgrp_fd; + linfo.cgroup.order = BPF_CGROUP_ITER_SELF_ONLY; + opts.link_info = &linfo; + opts.link_info_len = sizeof(linfo); + + link = bpf_program__attach_iter(skel->progs.cgroup_id_printer, &opts); + if (!ASSERT_OK_PTR(link, "attach_iter")) + goto close_cgrp; + + iter_fd = bpf_iter_create(bpf_link__fd(link)); + if (!ASSERT_GE(iter_fd, 0, "iter_create")) + goto free_link; + + /* Close link fd and cgroup fd */ + bpf_link__destroy(link); + close(cgrp_fd); + + /* Remove cgroup to mark it as dead */ + remove_cgroup(cgrp_name); + + /* Two kern_sync_rcu() and usleep() pairs are used to wait for the + * releases of cgroup css, and the last kern_sync_rcu() and usleep() + * pair is used to wait for the free of cgroup itself. + */ + kern_sync_rcu(); + usleep(8000); + kern_sync_rcu(); + usleep(8000); + kern_sync_rcu(); + usleep(1000); + + memset(buf, 0, sizeof(buf)); + left = ARRAY_SIZE(buf); + p = buf; + while ((len = read(iter_fd, p, left)) > 0) { + p += len; + left -= len; + } + + ASSERT_STREQ(buf, expected_output, "dead cgroup output"); + + /* read() after iter finishes should be ok. */ + if (len == 0) + ASSERT_OK(read(iter_fd, buf, sizeof(buf)), "second_read"); + + close(iter_fd); + return; +free_link: + bpf_link__destroy(link); +close_cgrp: + close(cgrp_fd); +} + void test_cgroup_iter(void) { struct cgroup_iter *skel = NULL; @@ -217,6 +291,8 @@ void test_cgroup_iter(void) test_early_termination(skel); if (test__start_subtest("cgroup_iter__self_only")) test_walk_self_only(skel); + if (test__start_subtest("cgroup_iter__dead_self_only")) + test_walk_dead_self_only(skel); out: cgroup_iter__destroy(skel); cleanup_cgroups(); From 114039b342014680911c35bd6b72624180fd669a Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Mon, 21 Nov 2022 10:03:39 -0800 Subject: [PATCH 072/101] bpf: Move skb->len == 0 checks into __bpf_redirect To avoid potentially breaking existing users. Both mac/no-mac cases have to be amended; mac_header >= network_header is not enough (verified with a new test, see next patch). Fixes: fd1894224407 ("bpf: Don't redirect packets with invalid pkt_len") Signed-off-by: Stanislav Fomichev Link: https://lore.kernel.org/r/20221121180340.1983627-1-sdf@google.com Signed-off-by: Martin KaFai Lau --- net/bpf/test_run.c | 3 --- net/core/filter.c | 11 ++++++----- 2 files changed, 6 insertions(+), 8 deletions(-) diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index 13d578ce2a09..6fba440efc40 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -979,9 +979,6 @@ static int convert___skb_to_skb(struct sk_buff *skb, struct __sk_buff *__skb) { struct qdisc_skb_cb *cb = (struct qdisc_skb_cb *)skb->cb; - if (!skb->len) - return -EINVAL; - if (!__skb) return 0; diff --git a/net/core/filter.c b/net/core/filter.c index 2a105fb1ceb2..b6e1b81cdfae 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2124,12 +2124,13 @@ static int __bpf_redirect_no_mac(struct sk_buff *skb, struct net_device *dev, { unsigned int mlen = skb_network_offset(skb); + if (unlikely(skb->len <= mlen)) { + kfree_skb(skb); + return -ERANGE; + } + if (mlen) { __skb_pull(skb, mlen); - if (unlikely(!skb->len)) { - kfree_skb(skb); - return -ERANGE; - } /* At ingress, the mac header has already been pulled once. * At egress, skb_pospull_rcsum has to be done in case that @@ -2149,7 +2150,7 @@ static int __bpf_redirect_common(struct sk_buff *skb, struct net_device *dev, u32 flags) { /* Verify that a link layer header is carried */ - if (unlikely(skb->mac_header >= skb->network_header)) { + if (unlikely(skb->mac_header >= skb->network_header || skb->len == 0)) { kfree_skb(skb); return -ERANGE; } From 68f8e3d4b916531ea3bb8b83e35138cf78f2fce5 Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Mon, 21 Nov 2022 10:03:40 -0800 Subject: [PATCH 073/101] selftests/bpf: Make sure zero-len skbs aren't redirectable LWT_XMIT to test L3 case, TC to test L2 case. v2: - s/veth_ifindex/ipip_ifindex/ in two places (Martin) - add comment about which condition triggers the rejection (Martin) Signed-off-by: Stanislav Fomichev Link: https://lore.kernel.org/r/20221121180340.1983627-2-sdf@google.com Signed-off-by: Martin KaFai Lau --- .../selftests/bpf/prog_tests/empty_skb.c | 146 ++++++++++++++++++ tools/testing/selftests/bpf/progs/empty_skb.c | 37 +++++ 2 files changed, 183 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/empty_skb.c create mode 100644 tools/testing/selftests/bpf/progs/empty_skb.c diff --git a/tools/testing/selftests/bpf/prog_tests/empty_skb.c b/tools/testing/selftests/bpf/prog_tests/empty_skb.c new file mode 100644 index 000000000000..32dd731e9070 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/empty_skb.c @@ -0,0 +1,146 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include "empty_skb.skel.h" + +#define SYS(cmd) ({ \ + if (!ASSERT_OK(system(cmd), (cmd))) \ + goto out; \ +}) + +void test_empty_skb(void) +{ + LIBBPF_OPTS(bpf_test_run_opts, tattr); + struct empty_skb *bpf_obj = NULL; + struct nstoken *tok = NULL; + struct bpf_program *prog; + char eth_hlen_pp[15]; + char eth_hlen[14]; + int veth_ifindex; + int ipip_ifindex; + int err; + int i; + + struct { + const char *msg; + const void *data_in; + __u32 data_size_in; + int *ifindex; + int err; + int ret; + bool success_on_tc; + } tests[] = { + /* Empty packets are always rejected. */ + + { + /* BPF_PROG_RUN ETH_HLEN size check */ + .msg = "veth empty ingress packet", + .data_in = NULL, + .data_size_in = 0, + .ifindex = &veth_ifindex, + .err = -EINVAL, + }, + { + /* BPF_PROG_RUN ETH_HLEN size check */ + .msg = "ipip empty ingress packet", + .data_in = NULL, + .data_size_in = 0, + .ifindex = &ipip_ifindex, + .err = -EINVAL, + }, + + /* ETH_HLEN-sized packets: + * - can not be redirected at LWT_XMIT + * - can be redirected at TC to non-tunneling dest + */ + + { + /* __bpf_redirect_common */ + .msg = "veth ETH_HLEN packet ingress", + .data_in = eth_hlen, + .data_size_in = sizeof(eth_hlen), + .ifindex = &veth_ifindex, + .ret = -ERANGE, + .success_on_tc = true, + }, + { + /* __bpf_redirect_no_mac + * + * lwt: skb->len=0 <= skb_network_offset=0 + * tc: skb->len=14 <= skb_network_offset=14 + */ + .msg = "ipip ETH_HLEN packet ingress", + .data_in = eth_hlen, + .data_size_in = sizeof(eth_hlen), + .ifindex = &ipip_ifindex, + .ret = -ERANGE, + }, + + /* ETH_HLEN+1-sized packet should be redirected. */ + + { + .msg = "veth ETH_HLEN+1 packet ingress", + .data_in = eth_hlen_pp, + .data_size_in = sizeof(eth_hlen_pp), + .ifindex = &veth_ifindex, + }, + { + .msg = "ipip ETH_HLEN+1 packet ingress", + .data_in = eth_hlen_pp, + .data_size_in = sizeof(eth_hlen_pp), + .ifindex = &ipip_ifindex, + }, + }; + + SYS("ip netns add empty_skb"); + tok = open_netns("empty_skb"); + SYS("ip link add veth0 type veth peer veth1"); + SYS("ip link set dev veth0 up"); + SYS("ip link set dev veth1 up"); + SYS("ip addr add 10.0.0.1/8 dev veth0"); + SYS("ip addr add 10.0.0.2/8 dev veth1"); + veth_ifindex = if_nametoindex("veth0"); + + SYS("ip link add ipip0 type ipip local 10.0.0.1 remote 10.0.0.2"); + SYS("ip link set ipip0 up"); + SYS("ip addr add 192.168.1.1/16 dev ipip0"); + ipip_ifindex = if_nametoindex("ipip0"); + + bpf_obj = empty_skb__open_and_load(); + if (!ASSERT_OK_PTR(bpf_obj, "open skeleton")) + goto out; + + for (i = 0; i < ARRAY_SIZE(tests); i++) { + bpf_object__for_each_program(prog, bpf_obj->obj) { + char buf[128]; + bool at_tc = !strncmp(bpf_program__section_name(prog), "tc", 2); + + tattr.data_in = tests[i].data_in; + tattr.data_size_in = tests[i].data_size_in; + + tattr.data_size_out = 0; + bpf_obj->bss->ifindex = *tests[i].ifindex; + bpf_obj->bss->ret = 0; + err = bpf_prog_test_run_opts(bpf_program__fd(prog), &tattr); + sprintf(buf, "err: %s [%s]", tests[i].msg, bpf_program__name(prog)); + + if (at_tc && tests[i].success_on_tc) + ASSERT_GE(err, 0, buf); + else + ASSERT_EQ(err, tests[i].err, buf); + sprintf(buf, "ret: %s [%s]", tests[i].msg, bpf_program__name(prog)); + if (at_tc && tests[i].success_on_tc) + ASSERT_GE(bpf_obj->bss->ret, 0, buf); + else + ASSERT_EQ(bpf_obj->bss->ret, tests[i].ret, buf); + } + } + +out: + if (bpf_obj) + empty_skb__destroy(bpf_obj); + if (tok) + close_netns(tok); + system("ip netns del empty_skb"); +} diff --git a/tools/testing/selftests/bpf/progs/empty_skb.c b/tools/testing/selftests/bpf/progs/empty_skb.c new file mode 100644 index 000000000000..4b0cd6753251 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/empty_skb.c @@ -0,0 +1,37 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause +#include +#include +#include + +char _license[] SEC("license") = "GPL"; + +int ifindex; +int ret; + +SEC("lwt_xmit") +int redirect_ingress(struct __sk_buff *skb) +{ + ret = bpf_clone_redirect(skb, ifindex, BPF_F_INGRESS); + return 0; +} + +SEC("lwt_xmit") +int redirect_egress(struct __sk_buff *skb) +{ + ret = bpf_clone_redirect(skb, ifindex, 0); + return 0; +} + +SEC("tc") +int tc_redirect_ingress(struct __sk_buff *skb) +{ + ret = bpf_clone_redirect(skb, ifindex, BPF_F_INGRESS); + return 0; +} + +SEC("tc") +int tc_redirect_egress(struct __sk_buff *skb) +{ + ret = bpf_clone_redirect(skb, ifindex, 0); + return 0; +} From 0b2971a2703c015b5737d66688c2c7c81a5e391b Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Tue, 22 Nov 2022 08:50:04 -0800 Subject: [PATCH 074/101] Revert "selftests/bpf: Temporarily disable linked list tests" This reverts commit 0a2f85a1be4328d29aefa54684d10c23a3298fef. Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/prog_tests/linked_list.c | 21 +++++++------------ .../testing/selftests/bpf/progs/linked_list.c | 11 +--------- .../testing/selftests/bpf/progs/linked_list.h | 2 -- .../selftests/bpf/progs/linked_list_fail.c | 16 +++++++------- 4 files changed, 16 insertions(+), 34 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/linked_list.c b/tools/testing/selftests/bpf/prog_tests/linked_list.c index 6170d36fe5fc..dd73d0a62c6e 100644 --- a/tools/testing/selftests/bpf/prog_tests/linked_list.c +++ b/tools/testing/selftests/bpf/prog_tests/linked_list.c @@ -24,9 +24,7 @@ static struct { { #test "_missing_lock_pop_back", \ "bpf_spin_lock at off=" #off " must be held for bpf_list_head" }, TEST(kptr, 32) -/* FIXME TEST(global, 16) -*/ TEST(map, 0) TEST(inner_map, 0) #undef TEST @@ -34,6 +32,9 @@ static struct { { #test "_kptr_incorrect_lock_" #op, \ "held lock and object are not in the same allocation\n" \ "bpf_spin_lock at off=32 must be held for bpf_list_head" }, \ + { #test "_global_incorrect_lock_" #op, \ + "held lock and object are not in the same allocation\n" \ + "bpf_spin_lock at off=16 must be held for bpf_list_head" }, \ { #test "_map_incorrect_lock_" #op, \ "held lock and object are not in the same allocation\n" \ "bpf_spin_lock at off=0 must be held for bpf_list_head" }, \ @@ -44,6 +45,10 @@ static struct { TEST(kptr, push_back) TEST(kptr, pop_front) TEST(kptr, pop_back) + TEST(global, push_front) + TEST(global, push_back) + TEST(global, pop_front) + TEST(global, pop_back) TEST(map, push_front) TEST(map, push_back) TEST(map, pop_front) @@ -53,14 +58,12 @@ static struct { TEST(inner_map, pop_front) TEST(inner_map, pop_back) #undef TEST -/* FIXME { "map_compat_kprobe", "tracing progs cannot use bpf_list_head yet" }, { "map_compat_kretprobe", "tracing progs cannot use bpf_list_head yet" }, { "map_compat_tp", "tracing progs cannot use bpf_list_head yet" }, { "map_compat_perf", "tracing progs cannot use bpf_list_head yet" }, { "map_compat_raw_tp", "tracing progs cannot use bpf_list_head yet" }, { "map_compat_raw_tp_w", "tracing progs cannot use bpf_list_head yet" }, -*/ { "obj_type_id_oor", "local type ID argument must be in range [0, U32_MAX]" }, { "obj_new_no_composite", "bpf_obj_new type ID argument must be of a struct" }, { "obj_new_no_struct", "bpf_obj_new type ID argument must be of a struct" }, @@ -75,7 +78,6 @@ static struct { { "direct_write_head", "direct access to bpf_list_head is disallowed" }, { "direct_read_node", "direct access to bpf_list_node is disallowed" }, { "direct_write_node", "direct access to bpf_list_node is disallowed" }, -/* FIXME { "write_after_push_front", "only read is supported" }, { "write_after_push_back", "only read is supported" }, { "use_after_unlock_push_front", "invalid mem access 'scalar'" }, @@ -92,11 +94,8 @@ static struct { { "no_head_type", "bpf_list_head not found at offset=0" }, { "incorrect_head_var_off1", "R1 doesn't have constant offset" }, { "incorrect_head_var_off2", "variable ptr_ access var_off=(0x0; 0xffffffff) disallowed" }, -*/ { "incorrect_head_off1", "bpf_list_head not found at offset=17" }, -/* FIXME { "incorrect_head_off2", "bpf_list_head not found at offset=1" }, -*/ { "pop_front_off", "15: (bf) r1 = r6 ; R1_w=ptr_or_null_foo(id=4,ref_obj_id=4,off=40,imm=0) " "R6_w=ptr_or_null_foo(id=4,ref_obj_id=4,off=40,imm=0) refs=2,4\n" @@ -189,10 +188,8 @@ static void test_linked_list_success(int mode, bool leave_in_map) ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.global_list_push_pop), &opts); ASSERT_OK(ret, "global_list_push_pop"); ASSERT_OK(opts.retval, "global_list_push_pop retval"); - /* FIXME: if (!leave_in_map) clear_fields(skel->maps.data_A); - */ if (mode == PUSH_POP) goto end; @@ -213,10 +210,8 @@ ppm: ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.global_list_push_pop_multiple), &opts); ASSERT_OK(ret, "global_list_push_pop_multiple"); ASSERT_OK(opts.retval, "global_list_push_pop_multiple retval"); - /* FIXME: if (!leave_in_map) clear_fields(skel->maps.data_A); - */ if (mode == PUSH_POP_MULT) goto end; @@ -237,10 +232,8 @@ lil: ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.global_list_in_list), &opts); ASSERT_OK(ret, "global_list_in_list"); ASSERT_OK(opts.retval, "global_list_in_list retval"); - /* FIXME: if (!leave_in_map) clear_fields(skel->maps.data_A); - */ end: linked_list__destroy(skel); } diff --git a/tools/testing/selftests/bpf/progs/linked_list.c b/tools/testing/selftests/bpf/progs/linked_list.c index a99103c86e48..2c7b615c6d41 100644 --- a/tools/testing/selftests/bpf/progs/linked_list.c +++ b/tools/testing/selftests/bpf/progs/linked_list.c @@ -291,10 +291,7 @@ int inner_map_list_push_pop(void *ctx) SEC("tc") int global_list_push_pop(void *ctx) { - /* FIXME: - * return test_list_push_pop(&glock, &ghead); - */ - return 0; + return test_list_push_pop(&glock, &ghead); } SEC("tc") @@ -330,13 +327,10 @@ int global_list_push_pop_multiple(void *ctx) { int ret; - /* FIXME: ret = list_push_pop_multiple(&glock, &ghead, false); if (ret) return ret; return list_push_pop_multiple(&glock, &ghead, true); - */ - return 0; } SEC("tc") @@ -370,10 +364,7 @@ int inner_map_list_in_list(void *ctx) SEC("tc") int global_list_in_list(void *ctx) { - /* FIXME return test_list_in_list(&glock, &ghead); - */ - return 0; } char _license[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/progs/linked_list.h b/tools/testing/selftests/bpf/progs/linked_list.h index 93157efc2d04..8db80ed64db1 100644 --- a/tools/testing/selftests/bpf/progs/linked_list.h +++ b/tools/testing/selftests/bpf/progs/linked_list.h @@ -47,12 +47,10 @@ struct { }, }; -/* FIXME #define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8))) private(A) struct bpf_spin_lock glock; private(A) struct bpf_list_head ghead __contains(foo, node); private(B) struct bpf_spin_lock glock2; -*/ #endif diff --git a/tools/testing/selftests/bpf/progs/linked_list_fail.c b/tools/testing/selftests/bpf/progs/linked_list_fail.c index 1b7ed1d3a9bb..1d9017240e19 100644 --- a/tools/testing/selftests/bpf/progs/linked_list_fail.c +++ b/tools/testing/selftests/bpf/progs/linked_list_fail.c @@ -59,12 +59,10 @@ CHECK(kptr, push_back, &f->head); CHECK(kptr, pop_front, &f->head); CHECK(kptr, pop_back, &f->head); -/* FIXME CHECK(global, push_front, &ghead); CHECK(global, push_back, &ghead); CHECK(global, pop_front, &ghead); CHECK(global, pop_back, &ghead); -*/ CHECK(map, push_front, &v->head); CHECK(map, push_back, &v->head); @@ -91,15 +89,23 @@ CHECK(inner_map, pop_back, &iv->head); #define CHECK_OP(op) \ CHECK(kptr_kptr, op, &f1->lock, &f2->head); \ + CHECK(kptr_global, op, &f1->lock, &ghead); \ CHECK(kptr_map, op, &f1->lock, &v->head); \ CHECK(kptr_inner_map, op, &f1->lock, &iv->head); \ \ + CHECK(global_global, op, &glock2, &ghead); \ + CHECK(global_kptr, op, &glock, &f1->head); \ + CHECK(global_map, op, &glock, &v->head); \ + CHECK(global_inner_map, op, &glock, &iv->head); \ + \ CHECK(map_map, op, &v->lock, &v2->head); \ CHECK(map_kptr, op, &v->lock, &f2->head); \ + CHECK(map_global, op, &v->lock, &ghead); \ CHECK(map_inner_map, op, &v->lock, &iv->head); \ \ CHECK(inner_map_inner_map, op, &iv->lock, &iv2->head); \ CHECK(inner_map_kptr, op, &iv->lock, &f2->head); \ + CHECK(inner_map_global, op, &iv->lock, &ghead); \ CHECK(inner_map_map, op, &iv->lock, &v->head); CHECK_OP(push_front); @@ -111,7 +117,6 @@ CHECK_OP(pop_back); #undef CHECK_OP #undef INIT -/* FIXME SEC("?kprobe/xyz") int map_compat_kprobe(void *ctx) { @@ -153,7 +158,6 @@ int map_compat_raw_tp_w(void *ctx) bpf_list_push_front(&ghead, NULL); return 0; } -*/ SEC("?tc") int obj_type_id_oor(void *ctx) @@ -299,7 +303,6 @@ int direct_write_node(void *ctx) return 0; } -/* FIXME static __always_inline int write_after_op(void (*push_op)(void *head, void *node)) { @@ -503,7 +506,6 @@ int incorrect_head_var_off2(struct __sk_buff *ctx) return 0; } -*/ SEC("?tc") int incorrect_head_off1(void *ctx) @@ -527,7 +529,6 @@ int incorrect_head_off1(void *ctx) return 0; } -/* FIXME SEC("?tc") int incorrect_head_off2(void *ctx) { @@ -544,7 +545,6 @@ int incorrect_head_off2(void *ctx) return 0; } -*/ static __always_inline int pop_ptr_off(void *(*op)(void *head)) From dc79f035b2062e4ff4f6432eda18f461f82b1333 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Tue, 22 Nov 2022 09:15:29 -0800 Subject: [PATCH 075/101] selftests/bpf: Workaround for llvm nop-4 bug Currently LLVM fails to recognize .data.* as data section and defaults to .text section. Later BPF backend tries to emit 4-byte NOP instruction which doesn't exist in BPF ISA and aborts. The fix for LLVM is pending: https://reviews.llvm.org/D138477 While waiting for the fix lets workaround the linked_list test case by using .bss.* prefix which is properly recognized by LLVM as BSS section. Fix libbpf to support .bss. prefix and adjust tests. Signed-off-by: Alexei Starovoitov --- tools/lib/bpf/libbpf.c | 3 ++- tools/testing/selftests/bpf/prog_tests/linked_list.c | 6 +++--- tools/testing/selftests/bpf/progs/linked_list.h | 2 +- 3 files changed, 6 insertions(+), 5 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index b5df6aca06ea..93ccea238391 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -3511,7 +3511,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj) sec_desc->sec_type = SEC_RELO; sec_desc->shdr = sh; sec_desc->data = data; - } else if (sh->sh_type == SHT_NOBITS && strcmp(name, BSS_SEC) == 0) { + } else if (sh->sh_type == SHT_NOBITS && (strcmp(name, BSS_SEC) == 0 || + str_has_pfx(name, BSS_SEC "."))) { sec_desc->sec_type = SEC_BSS; sec_desc->shdr = sh; sec_desc->data = data; diff --git a/tools/testing/selftests/bpf/prog_tests/linked_list.c b/tools/testing/selftests/bpf/prog_tests/linked_list.c index dd73d0a62c6e..9a7d4c47af63 100644 --- a/tools/testing/selftests/bpf/prog_tests/linked_list.c +++ b/tools/testing/selftests/bpf/prog_tests/linked_list.c @@ -189,7 +189,7 @@ static void test_linked_list_success(int mode, bool leave_in_map) ASSERT_OK(ret, "global_list_push_pop"); ASSERT_OK(opts.retval, "global_list_push_pop retval"); if (!leave_in_map) - clear_fields(skel->maps.data_A); + clear_fields(skel->maps.bss_A); if (mode == PUSH_POP) goto end; @@ -211,7 +211,7 @@ ppm: ASSERT_OK(ret, "global_list_push_pop_multiple"); ASSERT_OK(opts.retval, "global_list_push_pop_multiple retval"); if (!leave_in_map) - clear_fields(skel->maps.data_A); + clear_fields(skel->maps.bss_A); if (mode == PUSH_POP_MULT) goto end; @@ -233,7 +233,7 @@ lil: ASSERT_OK(ret, "global_list_in_list"); ASSERT_OK(opts.retval, "global_list_in_list retval"); if (!leave_in_map) - clear_fields(skel->maps.data_A); + clear_fields(skel->maps.bss_A); end: linked_list__destroy(skel); } diff --git a/tools/testing/selftests/bpf/progs/linked_list.h b/tools/testing/selftests/bpf/progs/linked_list.h index 8db80ed64db1..3fb2412552fc 100644 --- a/tools/testing/selftests/bpf/progs/linked_list.h +++ b/tools/testing/selftests/bpf/progs/linked_list.h @@ -47,7 +47,7 @@ struct { }, }; -#define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8))) +#define private(name) SEC(".bss." #name) __hidden __attribute__((aligned(8))) private(A) struct bpf_spin_lock glock; private(A) struct bpf_list_head ghead __contains(foo, node); From fda01efc61605af7c6fa03c4109f14d59c9228b7 Mon Sep 17 00:00:00 2001 From: David Vernet Date: Mon, 21 Nov 2022 23:54:55 -0600 Subject: [PATCH 076/101] bpf: Enable cgroups to be used as kptrs Now that tasks can be used as kfuncs, and the PTR_TRUSTED flag is available for us to easily add basic acquire / get / release kfuncs, we can do the same for cgroups. This patch set adds the following kfuncs which enable using cgroups as kptrs: struct cgroup *bpf_cgroup_acquire(struct cgroup *cgrp); struct cgroup *bpf_cgroup_kptr_get(struct cgroup **cgrpp); void bpf_cgroup_release(struct cgroup *cgrp); A follow-on patch will add a selftest suite which validates these kfuncs. Signed-off-by: David Vernet Link: https://lore.kernel.org/r/20221122055458.173143-2-void@manifault.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/helpers.c | 83 ++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 80 insertions(+), 3 deletions(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 9e8a5557ea8d..420a4251cccc 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -4,6 +4,7 @@ #include #include #include +#include #include #include #include @@ -1879,6 +1880,66 @@ void bpf_task_release(struct task_struct *p) put_task_struct_rcu_user(p); } +#ifdef CONFIG_CGROUPS +/** + * bpf_cgroup_acquire - Acquire a reference to a cgroup. A cgroup acquired by + * this kfunc which is not stored in a map as a kptr, must be released by + * calling bpf_cgroup_release(). + * @cgrp: The cgroup on which a reference is being acquired. + */ +struct cgroup *bpf_cgroup_acquire(struct cgroup *cgrp) +{ + cgroup_get(cgrp); + return cgrp; +} + +/** + * bpf_cgroup_kptr_get - Acquire a reference on a struct cgroup kptr. A cgroup + * kptr acquired by this kfunc which is not subsequently stored in a map, must + * be released by calling bpf_cgroup_release(). + * @cgrpp: A pointer to a cgroup kptr on which a reference is being acquired. + */ +struct cgroup *bpf_cgroup_kptr_get(struct cgroup **cgrpp) +{ + struct cgroup *cgrp; + + rcu_read_lock(); + /* Another context could remove the cgroup from the map and release it + * at any time, including after we've done the lookup above. This is + * safe because we're in an RCU read region, so the cgroup is + * guaranteed to remain valid until at least the rcu_read_unlock() + * below. + */ + cgrp = READ_ONCE(*cgrpp); + + if (cgrp && !cgroup_tryget(cgrp)) + /* If the cgroup had been removed from the map and freed as + * described above, cgroup_tryget() will return false. The + * cgroup will be freed at some point after the current RCU gp + * has ended, so just return NULL to the user. + */ + cgrp = NULL; + rcu_read_unlock(); + + return cgrp; +} + +/** + * bpf_cgroup_release - Release the reference acquired on a struct cgroup *. + * If this kfunc is invoked in an RCU read region, the cgroup is guaranteed to + * not be freed until the current grace period has ended, even if its refcount + * drops to 0. + * @cgrp: The cgroup on which a reference is being released. + */ +void bpf_cgroup_release(struct cgroup *cgrp) +{ + if (!cgrp) + return; + + cgroup_put(cgrp); +} +#endif /* CONFIG_CGROUPS */ + void *bpf_cast_to_kern_ctx(void *obj) { return obj; @@ -1904,6 +1965,12 @@ BTF_ID_FLAGS(func, bpf_list_pop_back, KF_ACQUIRE | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_task_acquire, KF_ACQUIRE | KF_TRUSTED_ARGS) BTF_ID_FLAGS(func, bpf_task_kptr_get, KF_ACQUIRE | KF_KPTR_GET | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_task_release, KF_RELEASE) + +#ifdef CONFIG_CGROUPS +BTF_ID_FLAGS(func, bpf_cgroup_acquire, KF_ACQUIRE | KF_TRUSTED_ARGS) +BTF_ID_FLAGS(func, bpf_cgroup_kptr_get, KF_ACQUIRE | KF_KPTR_GET | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_cgroup_release, KF_RELEASE) +#endif BTF_SET8_END(generic_btf_ids) static const struct btf_kfunc_id_set generic_kfunc_set = { @@ -1915,6 +1982,10 @@ static const struct btf_kfunc_id_set generic_kfunc_set = { BTF_ID_LIST(generic_dtor_ids) BTF_ID(struct, task_struct) BTF_ID(func, bpf_task_release) +#ifdef CONFIG_CGROUPS +BTF_ID(struct, cgroup) +BTF_ID(func, bpf_cgroup_release) +#endif BTF_SET8_START(common_btf_ids) BTF_ID_FLAGS(func, bpf_cast_to_kern_ctx) @@ -1928,12 +1999,18 @@ static const struct btf_kfunc_id_set common_kfunc_set = { static int __init kfunc_init(void) { - int ret; + int ret, idx = 0; const struct btf_id_dtor_kfunc generic_dtors[] = { { - .btf_id = generic_dtor_ids[0], - .kfunc_btf_id = generic_dtor_ids[1] + .btf_id = generic_dtor_ids[idx++], + .kfunc_btf_id = generic_dtor_ids[idx++] }, +#ifdef CONFIG_CGROUPS + { + .btf_id = generic_dtor_ids[idx++], + .kfunc_btf_id = generic_dtor_ids[idx++] + }, +#endif }; ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &generic_kfunc_set); From f583ddf15e57746e60f3b68d529afc9faa2e2cb3 Mon Sep 17 00:00:00 2001 From: David Vernet Date: Mon, 21 Nov 2022 23:54:56 -0600 Subject: [PATCH 077/101] selftests/bpf: Add cgroup kfunc / kptr selftests This patch adds a selftest suite to validate the cgroup kfuncs that were added in the prior patch. Signed-off-by: David Vernet Link: https://lore.kernel.org/r/20221122055458.173143-3-void@manifault.com Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/DENYLIST.s390x | 1 + .../selftests/bpf/prog_tests/cgrp_kfunc.c | 174 ++++++++++++ .../selftests/bpf/progs/cgrp_kfunc_common.h | 71 +++++ .../selftests/bpf/progs/cgrp_kfunc_failure.c | 260 ++++++++++++++++++ .../selftests/bpf/progs/cgrp_kfunc_success.c | 125 +++++++++ 5 files changed, 631 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/cgrp_kfunc.c create mode 100644 tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h create mode 100644 tools/testing/selftests/bpf/progs/cgrp_kfunc_failure.c create mode 100644 tools/testing/selftests/bpf/progs/cgrp_kfunc_success.c diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x index 12cf2159975e..b9a3d80204c6 100644 --- a/tools/testing/selftests/bpf/DENYLIST.s390x +++ b/tools/testing/selftests/bpf/DENYLIST.s390x @@ -10,6 +10,7 @@ bpf_nf # JIT does not support calling kernel f bpf_tcp_ca # JIT does not support calling kernel function (kfunc) cb_refs # expected error message unexpected error: -524 (trampoline) cgroup_hierarchical_stats # JIT does not support calling kernel function (kfunc) +cgrp_kfunc # JIT does not support calling kernel function cgrp_local_storage # prog_attach unexpected error: -524 (trampoline) core_read_macros # unknown func bpf_probe_read#4 (overlapping) d_path # failed to auto-attach program 'prog_stat': -524 (trampoline) diff --git a/tools/testing/selftests/bpf/prog_tests/cgrp_kfunc.c b/tools/testing/selftests/bpf/prog_tests/cgrp_kfunc.c new file mode 100644 index 000000000000..a59b166bbcc4 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/cgrp_kfunc.c @@ -0,0 +1,174 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ + +#define _GNU_SOURCE +#include +#include + +#include "cgrp_kfunc_failure.skel.h" +#include "cgrp_kfunc_success.skel.h" + +static size_t log_buf_sz = 1 << 20; /* 1 MB */ +static char obj_log_buf[1048576]; + +static struct cgrp_kfunc_success *open_load_cgrp_kfunc_skel(void) +{ + struct cgrp_kfunc_success *skel; + int err; + + skel = cgrp_kfunc_success__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return NULL; + + skel->bss->pid = getpid(); + + err = cgrp_kfunc_success__load(skel); + if (!ASSERT_OK(err, "skel_load")) + goto cleanup; + + return skel; + +cleanup: + cgrp_kfunc_success__destroy(skel); + return NULL; +} + +static int mkdir_rm_test_dir(void) +{ + int fd; + const char *cgrp_path = "cgrp_kfunc"; + + fd = create_and_get_cgroup(cgrp_path); + if (!ASSERT_GT(fd, 0, "mkdir_cgrp_fd")) + return -1; + + close(fd); + remove_cgroup(cgrp_path); + + return 0; +} + +static void run_success_test(const char *prog_name) +{ + struct cgrp_kfunc_success *skel; + struct bpf_program *prog; + struct bpf_link *link = NULL; + + skel = open_load_cgrp_kfunc_skel(); + if (!ASSERT_OK_PTR(skel, "open_load_skel")) + return; + + if (!ASSERT_OK(skel->bss->err, "pre_mkdir_err")) + goto cleanup; + + prog = bpf_object__find_program_by_name(skel->obj, prog_name); + if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name")) + goto cleanup; + + link = bpf_program__attach(prog); + if (!ASSERT_OK_PTR(link, "attached_link")) + goto cleanup; + + ASSERT_EQ(skel->bss->invocations, 0, "pre_rmdir_count"); + if (!ASSERT_OK(mkdir_rm_test_dir(), "cgrp_mkdir")) + goto cleanup; + + ASSERT_EQ(skel->bss->invocations, 1, "post_rmdir_count"); + ASSERT_OK(skel->bss->err, "post_rmdir_err"); + +cleanup: + bpf_link__destroy(link); + cgrp_kfunc_success__destroy(skel); +} + +static const char * const success_tests[] = { + "test_cgrp_acquire_release_argument", + "test_cgrp_acquire_leave_in_map", + "test_cgrp_xchg_release", + "test_cgrp_get_release", +}; + +static struct { + const char *prog_name; + const char *expected_err_msg; +} failure_tests[] = { + {"cgrp_kfunc_acquire_untrusted", "R1 must be referenced or trusted"}, + {"cgrp_kfunc_acquire_fp", "arg#0 pointer type STRUCT cgroup must point"}, + {"cgrp_kfunc_acquire_unsafe_kretprobe", "reg type unsupported for arg#0 function"}, + {"cgrp_kfunc_acquire_trusted_walked", "R1 must be referenced or trusted"}, + {"cgrp_kfunc_acquire_null", "arg#0 pointer type STRUCT cgroup must point"}, + {"cgrp_kfunc_acquire_unreleased", "Unreleased reference"}, + {"cgrp_kfunc_get_non_kptr_param", "arg#0 expected pointer to map value"}, + {"cgrp_kfunc_get_non_kptr_acquired", "arg#0 expected pointer to map value"}, + {"cgrp_kfunc_get_null", "arg#0 expected pointer to map value"}, + {"cgrp_kfunc_xchg_unreleased", "Unreleased reference"}, + {"cgrp_kfunc_get_unreleased", "Unreleased reference"}, + {"cgrp_kfunc_release_untrusted", "arg#0 is untrusted_ptr_or_null_ expected ptr_ or socket"}, + {"cgrp_kfunc_release_fp", "arg#0 pointer type STRUCT cgroup must point"}, + {"cgrp_kfunc_release_null", "arg#0 is ptr_or_null_ expected ptr_ or socket"}, + {"cgrp_kfunc_release_unacquired", "release kernel function bpf_cgroup_release expects"}, +}; + +static void verify_fail(const char *prog_name, const char *expected_err_msg) +{ + LIBBPF_OPTS(bpf_object_open_opts, opts); + struct cgrp_kfunc_failure *skel; + int err, i; + + opts.kernel_log_buf = obj_log_buf; + opts.kernel_log_size = log_buf_sz; + opts.kernel_log_level = 1; + + skel = cgrp_kfunc_failure__open_opts(&opts); + if (!ASSERT_OK_PTR(skel, "cgrp_kfunc_failure__open_opts")) + goto cleanup; + + for (i = 0; i < ARRAY_SIZE(failure_tests); i++) { + struct bpf_program *prog; + const char *curr_name = failure_tests[i].prog_name; + + prog = bpf_object__find_program_by_name(skel->obj, curr_name); + if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name")) + goto cleanup; + + bpf_program__set_autoload(prog, !strcmp(curr_name, prog_name)); + } + + err = cgrp_kfunc_failure__load(skel); + if (!ASSERT_ERR(err, "unexpected load success")) + goto cleanup; + + if (!ASSERT_OK_PTR(strstr(obj_log_buf, expected_err_msg), "expected_err_msg")) { + fprintf(stderr, "Expected err_msg: %s\n", expected_err_msg); + fprintf(stderr, "Verifier output: %s\n", obj_log_buf); + } + +cleanup: + cgrp_kfunc_failure__destroy(skel); +} + +void test_cgrp_kfunc(void) +{ + int i, err; + + err = setup_cgroup_environment(); + if (!ASSERT_OK(err, "cgrp_env_setup")) + goto cleanup; + + for (i = 0; i < ARRAY_SIZE(success_tests); i++) { + if (!test__start_subtest(success_tests[i])) + continue; + + run_success_test(success_tests[i]); + } + + for (i = 0; i < ARRAY_SIZE(failure_tests); i++) { + if (!test__start_subtest(failure_tests[i].prog_name)) + continue; + + verify_fail(failure_tests[i].prog_name, failure_tests[i].expected_err_msg); + } + +cleanup: + cleanup_cgroup_environment(); +} diff --git a/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h b/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h new file mode 100644 index 000000000000..3f18def0e45c --- /dev/null +++ b/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h @@ -0,0 +1,71 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ + +#ifndef _CGRP_KFUNC_COMMON_H +#define _CGRP_KFUNC_COMMON_H + +#include +#include +#include +#include + +struct __cgrps_kfunc_map_value { + struct cgroup __kptr_ref * cgrp; +}; + +struct hash_map { + __uint(type, BPF_MAP_TYPE_HASH); + __type(key, int); + __type(value, struct __cgrps_kfunc_map_value); + __uint(max_entries, 1); +} __cgrps_kfunc_map SEC(".maps"); + +struct cgroup *bpf_cgroup_acquire(struct cgroup *p) __ksym; +struct cgroup *bpf_cgroup_kptr_get(struct cgroup **pp) __ksym; +void bpf_cgroup_release(struct cgroup *p) __ksym; + +static inline struct __cgrps_kfunc_map_value *cgrps_kfunc_map_value_lookup(struct cgroup *cgrp) +{ + s32 id; + long status; + + status = bpf_probe_read_kernel(&id, sizeof(id), &cgrp->self.id); + if (status) + return NULL; + + return bpf_map_lookup_elem(&__cgrps_kfunc_map, &id); +} + +static inline int cgrps_kfunc_map_insert(struct cgroup *cgrp) +{ + struct __cgrps_kfunc_map_value local, *v; + long status; + struct cgroup *acquired, *old; + s32 id; + + status = bpf_probe_read_kernel(&id, sizeof(id), &cgrp->self.id); + if (status) + return status; + + local.cgrp = NULL; + status = bpf_map_update_elem(&__cgrps_kfunc_map, &id, &local, BPF_NOEXIST); + if (status) + return status; + + v = bpf_map_lookup_elem(&__cgrps_kfunc_map, &id); + if (!v) { + bpf_map_delete_elem(&__cgrps_kfunc_map, &id); + return -ENOENT; + } + + acquired = bpf_cgroup_acquire(cgrp); + old = bpf_kptr_xchg(&v->cgrp, acquired); + if (old) { + bpf_cgroup_release(old); + return -EEXIST; + } + + return 0; +} + +#endif /* _CGRP_KFUNC_COMMON_H */ diff --git a/tools/testing/selftests/bpf/progs/cgrp_kfunc_failure.c b/tools/testing/selftests/bpf/progs/cgrp_kfunc_failure.c new file mode 100644 index 000000000000..a1369b5ebcf8 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/cgrp_kfunc_failure.c @@ -0,0 +1,260 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ + +#include +#include +#include + +#include "cgrp_kfunc_common.h" + +char _license[] SEC("license") = "GPL"; + +/* Prototype for all of the program trace events below: + * + * TRACE_EVENT(cgroup_mkdir, + * TP_PROTO(struct cgroup *cgrp, const char *path), + * TP_ARGS(cgrp, path) + */ + +static struct __cgrps_kfunc_map_value *insert_lookup_cgrp(struct cgroup *cgrp) +{ + int status; + + status = cgrps_kfunc_map_insert(cgrp); + if (status) + return NULL; + + return cgrps_kfunc_map_value_lookup(cgrp); +} + +SEC("tp_btf/cgroup_mkdir") +int BPF_PROG(cgrp_kfunc_acquire_untrusted, struct cgroup *cgrp, const char *path) +{ + struct cgroup *acquired; + struct __cgrps_kfunc_map_value *v; + + v = insert_lookup_cgrp(cgrp); + if (!v) + return 0; + + /* Can't invoke bpf_cgroup_acquire() on an untrusted pointer. */ + acquired = bpf_cgroup_acquire(v->cgrp); + bpf_cgroup_release(acquired); + + return 0; +} + +SEC("tp_btf/cgroup_mkdir") +int BPF_PROG(cgrp_kfunc_acquire_fp, struct cgroup *cgrp, const char *path) +{ + struct cgroup *acquired, *stack_cgrp = (struct cgroup *)&path; + + /* Can't invoke bpf_cgroup_acquire() on a random frame pointer. */ + acquired = bpf_cgroup_acquire((struct cgroup *)&stack_cgrp); + bpf_cgroup_release(acquired); + + return 0; +} + +SEC("kretprobe/cgroup_destroy_locked") +int BPF_PROG(cgrp_kfunc_acquire_unsafe_kretprobe, struct cgroup *cgrp) +{ + struct cgroup *acquired; + + /* Can't acquire an untrusted struct cgroup * pointer. */ + acquired = bpf_cgroup_acquire(cgrp); + bpf_cgroup_release(acquired); + + return 0; +} + +SEC("tp_btf/cgroup_mkdir") +int BPF_PROG(cgrp_kfunc_acquire_trusted_walked, struct cgroup *cgrp, const char *path) +{ + struct cgroup *acquired; + + /* Can't invoke bpf_cgroup_acquire() on a pointer obtained from walking a trusted cgroup. */ + acquired = bpf_cgroup_acquire(cgrp->old_dom_cgrp); + bpf_cgroup_release(acquired); + + return 0; +} + + +SEC("tp_btf/cgroup_mkdir") +int BPF_PROG(cgrp_kfunc_acquire_null, struct cgroup *cgrp, const char *path) +{ + struct cgroup *acquired; + + /* Can't invoke bpf_cgroup_acquire() on a NULL pointer. */ + acquired = bpf_cgroup_acquire(NULL); + if (!acquired) + return 0; + bpf_cgroup_release(acquired); + + return 0; +} + +SEC("tp_btf/cgroup_mkdir") +int BPF_PROG(cgrp_kfunc_acquire_unreleased, struct cgroup *cgrp, const char *path) +{ + struct cgroup *acquired; + + acquired = bpf_cgroup_acquire(cgrp); + + /* Acquired cgroup is never released. */ + + return 0; +} + +SEC("tp_btf/cgroup_mkdir") +int BPF_PROG(cgrp_kfunc_get_non_kptr_param, struct cgroup *cgrp, const char *path) +{ + struct cgroup *kptr; + + /* Cannot use bpf_cgroup_kptr_get() on a non-kptr, even on a valid cgroup. */ + kptr = bpf_cgroup_kptr_get(&cgrp); + if (!kptr) + return 0; + + bpf_cgroup_release(kptr); + + return 0; +} + +SEC("tp_btf/cgroup_mkdir") +int BPF_PROG(cgrp_kfunc_get_non_kptr_acquired, struct cgroup *cgrp, const char *path) +{ + struct cgroup *kptr, *acquired; + + acquired = bpf_cgroup_acquire(cgrp); + + /* Cannot use bpf_cgroup_kptr_get() on a non-map-value, even if the kptr was acquired. */ + kptr = bpf_cgroup_kptr_get(&acquired); + bpf_cgroup_release(acquired); + if (!kptr) + return 0; + + bpf_cgroup_release(kptr); + + return 0; +} + +SEC("tp_btf/cgroup_mkdir") +int BPF_PROG(cgrp_kfunc_get_null, struct cgroup *cgrp, const char *path) +{ + struct cgroup *kptr; + + /* Cannot use bpf_cgroup_kptr_get() on a NULL pointer. */ + kptr = bpf_cgroup_kptr_get(NULL); + if (!kptr) + return 0; + + bpf_cgroup_release(kptr); + + return 0; +} + +SEC("tp_btf/cgroup_mkdir") +int BPF_PROG(cgrp_kfunc_xchg_unreleased, struct cgroup *cgrp, const char *path) +{ + struct cgroup *kptr; + struct __cgrps_kfunc_map_value *v; + + v = insert_lookup_cgrp(cgrp); + if (!v) + return 0; + + kptr = bpf_kptr_xchg(&v->cgrp, NULL); + if (!kptr) + return 0; + + /* Kptr retrieved from map is never released. */ + + return 0; +} + +SEC("tp_btf/cgroup_mkdir") +int BPF_PROG(cgrp_kfunc_get_unreleased, struct cgroup *cgrp, const char *path) +{ + struct cgroup *kptr; + struct __cgrps_kfunc_map_value *v; + + v = insert_lookup_cgrp(cgrp); + if (!v) + return 0; + + kptr = bpf_cgroup_kptr_get(&v->cgrp); + if (!kptr) + return 0; + + /* Kptr acquired above is never released. */ + + return 0; +} + +SEC("tp_btf/cgroup_mkdir") +int BPF_PROG(cgrp_kfunc_release_untrusted, struct cgroup *cgrp, const char *path) +{ + struct __cgrps_kfunc_map_value *v; + + v = insert_lookup_cgrp(cgrp); + if (!v) + return 0; + + /* Can't invoke bpf_cgroup_release() on an untrusted pointer. */ + bpf_cgroup_release(v->cgrp); + + return 0; +} + +SEC("tp_btf/cgroup_mkdir") +int BPF_PROG(cgrp_kfunc_release_fp, struct cgroup *cgrp, const char *path) +{ + struct cgroup *acquired = (struct cgroup *)&path; + + /* Cannot release random frame pointer. */ + bpf_cgroup_release(acquired); + + return 0; +} + +SEC("tp_btf/cgroup_mkdir") +int BPF_PROG(cgrp_kfunc_release_null, struct cgroup *cgrp, const char *path) +{ + struct __cgrps_kfunc_map_value local, *v; + long status; + struct cgroup *acquired, *old; + s32 id; + + status = bpf_probe_read_kernel(&id, sizeof(id), &cgrp->self.id); + if (status) + return 0; + + local.cgrp = NULL; + status = bpf_map_update_elem(&__cgrps_kfunc_map, &id, &local, BPF_NOEXIST); + if (status) + return status; + + v = bpf_map_lookup_elem(&__cgrps_kfunc_map, &id); + if (!v) + return -ENOENT; + + acquired = bpf_cgroup_acquire(cgrp); + + old = bpf_kptr_xchg(&v->cgrp, acquired); + + /* old cannot be passed to bpf_cgroup_release() without a NULL check. */ + bpf_cgroup_release(old); + + return 0; +} + +SEC("tp_btf/cgroup_mkdir") +int BPF_PROG(cgrp_kfunc_release_unacquired, struct cgroup *cgrp, const char *path) +{ + /* Cannot release trusted cgroup pointer which was not acquired. */ + bpf_cgroup_release(cgrp); + + return 0; +} diff --git a/tools/testing/selftests/bpf/progs/cgrp_kfunc_success.c b/tools/testing/selftests/bpf/progs/cgrp_kfunc_success.c new file mode 100644 index 000000000000..9f4569f7598b --- /dev/null +++ b/tools/testing/selftests/bpf/progs/cgrp_kfunc_success.c @@ -0,0 +1,125 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ + +#include +#include +#include + +#include "cgrp_kfunc_common.h" + +char _license[] SEC("license") = "GPL"; + +int err, pid, invocations; + +/* Prototype for all of the program trace events below: + * + * TRACE_EVENT(cgroup_mkdir, + * TP_PROTO(struct cgroup *cgrp, const char *path), + * TP_ARGS(cgrp, path) + */ + +static bool is_test_kfunc_task(void) +{ + int cur_pid = bpf_get_current_pid_tgid() >> 32; + bool same = pid == cur_pid; + + if (same) + __sync_fetch_and_add(&invocations, 1); + + return same; +} + +SEC("tp_btf/cgroup_mkdir") +int BPF_PROG(test_cgrp_acquire_release_argument, struct cgroup *cgrp, const char *path) +{ + struct cgroup *acquired; + + if (!is_test_kfunc_task()) + return 0; + + acquired = bpf_cgroup_acquire(cgrp); + bpf_cgroup_release(acquired); + + return 0; +} + +SEC("tp_btf/cgroup_mkdir") +int BPF_PROG(test_cgrp_acquire_leave_in_map, struct cgroup *cgrp, const char *path) +{ + long status; + + if (!is_test_kfunc_task()) + return 0; + + status = cgrps_kfunc_map_insert(cgrp); + if (status) + err = 1; + + return 0; +} + +SEC("tp_btf/cgroup_mkdir") +int BPF_PROG(test_cgrp_xchg_release, struct cgroup *cgrp, const char *path) +{ + struct cgroup *kptr; + struct __cgrps_kfunc_map_value *v; + long status; + + if (!is_test_kfunc_task()) + return 0; + + status = cgrps_kfunc_map_insert(cgrp); + if (status) { + err = 1; + return 0; + } + + v = cgrps_kfunc_map_value_lookup(cgrp); + if (!v) { + err = 2; + return 0; + } + + kptr = bpf_kptr_xchg(&v->cgrp, NULL); + if (!kptr) { + err = 3; + return 0; + } + + bpf_cgroup_release(kptr); + + return 0; +} + +SEC("tp_btf/cgroup_mkdir") +int BPF_PROG(test_cgrp_get_release, struct cgroup *cgrp, const char *path) +{ + struct cgroup *kptr; + struct __cgrps_kfunc_map_value *v; + long status; + + if (!is_test_kfunc_task()) + return 0; + + status = cgrps_kfunc_map_insert(cgrp); + if (status) { + err = 1; + return 0; + } + + v = cgrps_kfunc_map_value_lookup(cgrp); + if (!v) { + err = 2; + return 0; + } + + kptr = bpf_cgroup_kptr_get(&v->cgrp); + if (!kptr) { + err = 3; + return 0; + } + + bpf_cgroup_release(kptr); + + return 0; +} From 5ca7867078296cfa9c100f9a3b2d24be1e139825 Mon Sep 17 00:00:00 2001 From: David Vernet Date: Mon, 21 Nov 2022 23:54:57 -0600 Subject: [PATCH 078/101] bpf: Add bpf_cgroup_ancestor() kfunc struct cgroup * objects have a variably sized struct cgroup *ancestors[] field which stores pointers to their ancestor cgroups. If using a cgroup as a kptr, it can be useful to access these ancestors, but doing so requires variable offset accesses for PTR_TO_BTF_ID, which is currently unsupported. This is a very useful field to access for cgroup kptrs, as programs may wish to walk their ancestor cgroups when determining e.g. their proportional cpu.weight. So as to enable this functionality with cgroup kptrs before var_off is supported for PTR_TO_BTF_ID, this patch adds a bpf_cgroup_ancestor() kfunc which accesses the cgroup node on behalf of the caller, and acquires a reference on it. Once var_off is supported for PTR_TO_BTF_ID, and fields inside a struct can be marked as trusted so they retain the PTR_TRUSTED modifier when walked, this can be removed. Signed-off-by: David Vernet Link: https://lore.kernel.org/r/20221122055458.173143-4-void@manifault.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/helpers.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 420a4251cccc..e4e9db301db5 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1938,6 +1938,25 @@ void bpf_cgroup_release(struct cgroup *cgrp) cgroup_put(cgrp); } + +/** + * bpf_cgroup_ancestor - Perform a lookup on an entry in a cgroup's ancestor + * array. A cgroup returned by this kfunc which is not subsequently stored in a + * map, must be released by calling bpf_cgroup_release(). + * @cgrp: The cgroup for which we're performing a lookup. + * @level: The level of ancestor to look up. + */ +struct cgroup *bpf_cgroup_ancestor(struct cgroup *cgrp, int level) +{ + struct cgroup *ancestor; + + if (level > cgrp->level || level < 0) + return NULL; + + ancestor = cgrp->ancestors[level]; + cgroup_get(ancestor); + return ancestor; +} #endif /* CONFIG_CGROUPS */ void *bpf_cast_to_kern_ctx(void *obj) @@ -1970,6 +1989,7 @@ BTF_ID_FLAGS(func, bpf_task_release, KF_RELEASE) BTF_ID_FLAGS(func, bpf_cgroup_acquire, KF_ACQUIRE | KF_TRUSTED_ARGS) BTF_ID_FLAGS(func, bpf_cgroup_kptr_get, KF_ACQUIRE | KF_KPTR_GET | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_cgroup_release, KF_RELEASE) +BTF_ID_FLAGS(func, bpf_cgroup_ancestor, KF_ACQUIRE | KF_TRUSTED_ARGS | KF_RET_NULL) #endif BTF_SET8_END(generic_btf_ids) From 227a89cf504188759fd3d8933a3a06fc60cca7f2 Mon Sep 17 00:00:00 2001 From: David Vernet Date: Mon, 21 Nov 2022 23:54:58 -0600 Subject: [PATCH 079/101] selftests/bpf: Add selftests for bpf_cgroup_ancestor() kfunc bpf_cgroup_ancestor() allows BPF programs to access the ancestor of a struct cgroup *. This patch adds selftests that validate its expected behavior. Signed-off-by: David Vernet Link: https://lore.kernel.org/r/20221122055458.173143-5-void@manifault.com Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/prog_tests/cgrp_kfunc.c | 1 + .../selftests/bpf/progs/cgrp_kfunc_common.h | 1 + .../selftests/bpf/progs/cgrp_kfunc_success.c | 45 +++++++++++++++++++ 3 files changed, 47 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/cgrp_kfunc.c b/tools/testing/selftests/bpf/prog_tests/cgrp_kfunc.c index a59b166bbcc4..973f0c5af965 100644 --- a/tools/testing/selftests/bpf/prog_tests/cgrp_kfunc.c +++ b/tools/testing/selftests/bpf/prog_tests/cgrp_kfunc.c @@ -86,6 +86,7 @@ static const char * const success_tests[] = { "test_cgrp_acquire_leave_in_map", "test_cgrp_xchg_release", "test_cgrp_get_release", + "test_cgrp_get_ancestors", }; static struct { diff --git a/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h b/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h index 3f18def0e45c..7d30855bfe78 100644 --- a/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h +++ b/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h @@ -23,6 +23,7 @@ struct hash_map { struct cgroup *bpf_cgroup_acquire(struct cgroup *p) __ksym; struct cgroup *bpf_cgroup_kptr_get(struct cgroup **pp) __ksym; void bpf_cgroup_release(struct cgroup *p) __ksym; +struct cgroup *bpf_cgroup_ancestor(struct cgroup *cgrp, int level) __ksym; static inline struct __cgrps_kfunc_map_value *cgrps_kfunc_map_value_lookup(struct cgroup *cgrp) { diff --git a/tools/testing/selftests/bpf/progs/cgrp_kfunc_success.c b/tools/testing/selftests/bpf/progs/cgrp_kfunc_success.c index 9f4569f7598b..0c23ea32df9f 100644 --- a/tools/testing/selftests/bpf/progs/cgrp_kfunc_success.c +++ b/tools/testing/selftests/bpf/progs/cgrp_kfunc_success.c @@ -123,3 +123,48 @@ int BPF_PROG(test_cgrp_get_release, struct cgroup *cgrp, const char *path) return 0; } + +SEC("tp_btf/cgroup_mkdir") +int BPF_PROG(test_cgrp_get_ancestors, struct cgroup *cgrp, const char *path) +{ + struct cgroup *self, *ancestor1, *invalid; + + if (!is_test_kfunc_task()) + return 0; + + self = bpf_cgroup_ancestor(cgrp, cgrp->level); + if (!self) { + err = 1; + return 0; + } + + if (self->self.id != cgrp->self.id) { + bpf_cgroup_release(self); + err = 2; + return 0; + } + bpf_cgroup_release(self); + + ancestor1 = bpf_cgroup_ancestor(cgrp, cgrp->level - 1); + if (!ancestor1) { + err = 3; + return 0; + } + bpf_cgroup_release(ancestor1); + + invalid = bpf_cgroup_ancestor(cgrp, 10000); + if (invalid) { + bpf_cgroup_release(invalid); + err = 4; + return 0; + } + + invalid = bpf_cgroup_ancestor(cgrp, -1); + if (invalid) { + bpf_cgroup_release(invalid); + err = 5; + return 0; + } + + return 0; +} From 2fcc6081a7bf8f7f531cffdc58b630b822e700a1 Mon Sep 17 00:00:00 2001 From: David Vernet Date: Wed, 23 Nov 2022 07:52:53 -0600 Subject: [PATCH 080/101] bpf: Don't use idx variable when registering kfunc dtors In commit fda01efc6160 ("bpf: Enable cgroups to be used as kptrs"), I added an 'int idx' variable to kfunc_init() which was meant to dynamically set the index of the btf id entries of the 'generic_dtor_ids' array. This was done to make the code slightly less brittle as the struct cgroup * kptr kfuncs such as bpf_cgroup_aquire() are compiled out if CONFIG_CGROUPS is not defined. This, however, causes an lkp build warning: >> kernel/bpf/helpers.c:2005:40: warning: multiple unsequenced modifications to 'idx' [-Wunsequenced] .btf_id = generic_dtor_ids[idx++], Fix the warning by just hard-coding the indices. Fixes: fda01efc6160 ("bpf: Enable cgroups to be used as kptrs") Reported-by: kernel test robot Signed-off-by: David Vernet Acked-by: Yonghong Song Link: https://lore.kernel.org/r/20221123135253.637525-1-void@manifault.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/helpers.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index e4e9db301db5..da2681ebb7c3 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -2019,16 +2019,16 @@ static const struct btf_kfunc_id_set common_kfunc_set = { static int __init kfunc_init(void) { - int ret, idx = 0; + int ret; const struct btf_id_dtor_kfunc generic_dtors[] = { { - .btf_id = generic_dtor_ids[idx++], - .kfunc_btf_id = generic_dtor_ids[idx++] + .btf_id = generic_dtor_ids[0], + .kfunc_btf_id = generic_dtor_ids[1] }, #ifdef CONFIG_CGROUPS { - .btf_id = generic_dtor_ids[idx++], - .kfunc_btf_id = generic_dtor_ids[idx++] + .btf_id = generic_dtor_ids[2], + .kfunc_btf_id = generic_dtor_ids[3] }, #endif }; From 8ac88eece8009428e2577c345080a458e4507e2f Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Wed, 23 Nov 2022 12:08:29 -0800 Subject: [PATCH 081/101] selftests/bpf: Mount debugfs in setns_by_fd Jiri reports broken test_progs after recent commit 68f8e3d4b916 ("selftests/bpf: Make sure zero-len skbs aren't redirectable"). Apparently we don't remount debugfs when we switch back networking namespace. Let's explicitly mount /sys/kernel/debug. 0: https://lore.kernel.org/bpf/63b85917-a2ea-8e35-620c-808560910819@meta.com/T/#ma66ca9c92e99eee0a25e40f422489b26ee0171c1 Fixes: a30338840fa5 ("selftests/bpf: Move open_netns() and close_netns() into network_helpers.c") Reported-by: Jiri Olsa Signed-off-by: Stanislav Fomichev Link: https://lore.kernel.org/r/20221123200829.2226254-1-sdf@google.com Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/network_helpers.c | 4 ++++ tools/testing/selftests/bpf/prog_tests/empty_skb.c | 2 +- tools/testing/selftests/bpf/prog_tests/xdp_do_redirect.c | 2 +- tools/testing/selftests/bpf/prog_tests/xdp_synproxy.c | 2 +- 4 files changed, 7 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c index bec15558fd93..1f37adff7632 100644 --- a/tools/testing/selftests/bpf/network_helpers.c +++ b/tools/testing/selftests/bpf/network_helpers.c @@ -426,6 +426,10 @@ static int setns_by_fd(int nsfd) if (!ASSERT_OK(err, "mount /sys/fs/bpf")) return err; + err = mount("debugfs", "/sys/kernel/debug", "debugfs", 0, NULL); + if (!ASSERT_OK(err, "mount /sys/kernel/debug")) + return err; + return 0; } diff --git a/tools/testing/selftests/bpf/prog_tests/empty_skb.c b/tools/testing/selftests/bpf/prog_tests/empty_skb.c index 32dd731e9070..0613f3bb8b5e 100644 --- a/tools/testing/selftests/bpf/prog_tests/empty_skb.c +++ b/tools/testing/selftests/bpf/prog_tests/empty_skb.c @@ -9,7 +9,7 @@ goto out; \ }) -void test_empty_skb(void) +void serial_test_empty_skb(void) { LIBBPF_OPTS(bpf_test_run_opts, tattr); struct empty_skb *bpf_obj = NULL; diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_do_redirect.c b/tools/testing/selftests/bpf/prog_tests/xdp_do_redirect.c index a50971c6cf4a..9ac6f6a268db 100644 --- a/tools/testing/selftests/bpf/prog_tests/xdp_do_redirect.c +++ b/tools/testing/selftests/bpf/prog_tests/xdp_do_redirect.c @@ -85,7 +85,7 @@ static void test_max_pkt_size(int fd) } #define NUM_PKTS 10000 -void test_xdp_do_redirect(void) +void serial_test_xdp_do_redirect(void) { int err, xdp_prog_fd, tc_prog_fd, ifindex_src, ifindex_dst; char data[sizeof(pkt_udp) + sizeof(__u32)]; diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_synproxy.c b/tools/testing/selftests/bpf/prog_tests/xdp_synproxy.c index c72083885b6d..13daa3746064 100644 --- a/tools/testing/selftests/bpf/prog_tests/xdp_synproxy.c +++ b/tools/testing/selftests/bpf/prog_tests/xdp_synproxy.c @@ -174,7 +174,7 @@ out: system("ip netns del synproxy"); } -void test_xdp_synproxy(void) +void serial_test_xdp_synproxy(void) { if (test__start_subtest("xdp")) test_synproxy(true); From beb3d47d1d3d7185bb401af628ad32ee204a9526 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Wed, 23 Nov 2022 07:57:59 -0800 Subject: [PATCH 082/101] bpf: Fix a BTF_ID_LIST bug with CONFIG_DEBUG_INFO_BTF not set With CONFIG_DEBUG_INFO_BTF not set, we hit the following compilation error, /.../kernel/bpf/verifier.c:8196:23: error: array index 6 is past the end of the array (that has type 'u32[5]' (aka 'unsigned int[5]')) [-Werror,-Warray-bounds] if (meta->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx]) ^ ~~~~~~~~~~~~~~~~~~~~~~~ /.../kernel/bpf/verifier.c:8174:1: note: array 'special_kfunc_list' declared here BTF_ID_LIST(special_kfunc_list) ^ /.../include/linux/btf_ids.h:207:27: note: expanded from macro 'BTF_ID_LIST' #define BTF_ID_LIST(name) static u32 __maybe_unused name[5]; ^ /.../kernel/bpf/verifier.c:8443:19: error: array index 5 is past the end of the array (that has type 'u32[5]' (aka 'unsigned int[5]')) [-Werror,-Warray-bounds] btf_id == special_kfunc_list[KF_bpf_list_pop_back]; ^ ~~~~~~~~~~~~~~~~~~~~ /.../kernel/bpf/verifier.c:8174:1: note: array 'special_kfunc_list' declared here BTF_ID_LIST(special_kfunc_list) ^ /.../include/linux/btf_ids.h:207:27: note: expanded from macro 'BTF_ID_LIST' #define BTF_ID_LIST(name) static u32 __maybe_unused name[5]; ... Fix the problem by increase the size of BTF_ID_LIST to 16 to avoid compilation error and also prevent potentially unintended issue due to out-of-bound access. Reported-by: kernel test robot Reported-by: Dan Carpenter Reported-by: Nathan Chancellor Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20221123155759.2669749-1-yhs@fb.com Signed-off-by: Alexei Starovoitov --- include/linux/btf_ids.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h index c9744efd202f..93397711a68c 100644 --- a/include/linux/btf_ids.h +++ b/include/linux/btf_ids.h @@ -204,7 +204,7 @@ extern struct btf_id_set8 name; #else -#define BTF_ID_LIST(name) static u32 __maybe_unused name[5]; +#define BTF_ID_LIST(name) static u32 __maybe_unused name[16]; #define BTF_ID(prefix, name) #define BTF_ID_FLAGS(prefix, name, ...) #define BTF_ID_UNUSED From c742cb7c3ebdeb358794b9c76d93d8be7b631b9a Mon Sep 17 00:00:00 2001 From: Donald Hunter Date: Mon, 21 Nov 2022 12:17:34 +0000 Subject: [PATCH 083/101] docs/bpf: Add table of BPF program types to libbpf docs Extend the libbpf documentation with a table of program types, attach points and ELF section names. Signed-off-by: Donald Hunter Signed-off-by: Andrii Nakryiko Reviewed-by: Bagas Sanjaya Acked-by: David Vernet Link: https://lore.kernel.org/bpf/20221121121734.98329-1-donald.hunter@gmail.com --- Documentation/bpf/libbpf/index.rst | 3 + Documentation/bpf/libbpf/program_types.rst | 203 +++++++++++++++++++++ Documentation/bpf/programs.rst | 3 + 3 files changed, 209 insertions(+) create mode 100644 Documentation/bpf/libbpf/program_types.rst diff --git a/Documentation/bpf/libbpf/index.rst b/Documentation/bpf/libbpf/index.rst index 3722537d1384..f9b3b252e28f 100644 --- a/Documentation/bpf/libbpf/index.rst +++ b/Documentation/bpf/libbpf/index.rst @@ -1,5 +1,7 @@ .. SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) +.. _libbpf: + libbpf ====== @@ -7,6 +9,7 @@ libbpf :maxdepth: 1 API Documentation + program_types libbpf_naming_convention libbpf_build diff --git a/Documentation/bpf/libbpf/program_types.rst b/Documentation/bpf/libbpf/program_types.rst new file mode 100644 index 000000000000..ad4d4d5eecb0 --- /dev/null +++ b/Documentation/bpf/libbpf/program_types.rst @@ -0,0 +1,203 @@ +.. SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) + +.. _program_types_and_elf: + +Program Types and ELF Sections +============================== + +The table below lists the program types, their attach types where relevant and the ELF section +names supported by libbpf for them. The ELF section names follow these rules: + +- ``type`` is an exact match, e.g. ``SEC("socket")`` +- ``type+`` means it can be either exact ``SEC("type")`` or well-formed ``SEC("type/extras")`` + with a '``/``' separator between ``type`` and ``extras``. + +When ``extras`` are specified, they provide details of how to auto-attach the BPF program. The +format of ``extras`` depends on the program type, e.g. ``SEC("tracepoint//")`` +for tracepoints or ``SEC("usdt/::")`` for USDT probes. The extras are +described in more detail in the footnotes. + + ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| Program Type | Attach Type | ELF Section Name | Sleepable | ++===========================================+========================================+==================================+===========+ +| ``BPF_PROG_TYPE_CGROUP_DEVICE`` | ``BPF_CGROUP_DEVICE`` | ``cgroup/dev`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_CGROUP_SKB`` | | ``cgroup/skb`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_CGROUP_INET_EGRESS`` | ``cgroup_skb/egress`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_CGROUP_INET_INGRESS`` | ``cgroup_skb/ingress`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_CGROUP_SOCKOPT`` | ``BPF_CGROUP_GETSOCKOPT`` | ``cgroup/getsockopt`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_CGROUP_SETSOCKOPT`` | ``cgroup/setsockopt`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_CGROUP_SOCK_ADDR`` | ``BPF_CGROUP_INET4_BIND`` | ``cgroup/bind4`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_CGROUP_INET4_CONNECT`` | ``cgroup/connect4`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_CGROUP_INET4_GETPEERNAME`` | ``cgroup/getpeername4`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_CGROUP_INET4_GETSOCKNAME`` | ``cgroup/getsockname4`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_CGROUP_INET6_BIND`` | ``cgroup/bind6`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_CGROUP_INET6_CONNECT`` | ``cgroup/connect6`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_CGROUP_INET6_GETPEERNAME`` | ``cgroup/getpeername6`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_CGROUP_INET6_GETSOCKNAME`` | ``cgroup/getsockname6`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_CGROUP_UDP4_RECVMSG`` | ``cgroup/recvmsg4`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_CGROUP_UDP4_SENDMSG`` | ``cgroup/sendmsg4`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_CGROUP_UDP6_RECVMSG`` | ``cgroup/recvmsg6`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_CGROUP_UDP6_SENDMSG`` | ``cgroup/sendmsg6`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_CGROUP_SOCK`` | ``BPF_CGROUP_INET4_POST_BIND`` | ``cgroup/post_bind4`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_CGROUP_INET6_POST_BIND`` | ``cgroup/post_bind6`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_CGROUP_INET_SOCK_CREATE`` | ``cgroup/sock_create`` | | ++ + +----------------------------------+-----------+ +| | | ``cgroup/sock`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_CGROUP_INET_SOCK_RELEASE`` | ``cgroup/sock_release`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_CGROUP_SYSCTL`` | ``BPF_CGROUP_SYSCTL`` | ``cgroup/sysctl`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_EXT`` | | ``freplace+`` [#fentry]_ | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_FLOW_DISSECTOR`` | ``BPF_FLOW_DISSECTOR`` | ``flow_dissector`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_KPROBE`` | | ``kprobe+`` [#kprobe]_ | | ++ + +----------------------------------+-----------+ +| | | ``kretprobe+`` [#kprobe]_ | | ++ + +----------------------------------+-----------+ +| | | ``ksyscall+`` [#ksyscall]_ | | ++ + +----------------------------------+-----------+ +| | | ``kretsyscall+`` [#ksyscall]_ | | ++ + +----------------------------------+-----------+ +| | | ``uprobe+`` [#uprobe]_ | | ++ + +----------------------------------+-----------+ +| | | ``uprobe.s+`` [#uprobe]_ | Yes | ++ + +----------------------------------+-----------+ +| | | ``uretprobe+`` [#uprobe]_ | | ++ + +----------------------------------+-----------+ +| | | ``uretprobe.s+`` [#uprobe]_ | Yes | ++ + +----------------------------------+-----------+ +| | | ``usdt+`` [#usdt]_ | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_TRACE_KPROBE_MULTI`` | ``kprobe.multi+`` [#kpmulti]_ | | ++ + +----------------------------------+-----------+ +| | | ``kretprobe.multi+`` [#kpmulti]_ | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_LIRC_MODE2`` | ``BPF_LIRC_MODE2`` | ``lirc_mode2`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_LSM`` | ``BPF_LSM_CGROUP`` | ``lsm_cgroup+`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_LSM_MAC`` | ``lsm+`` [#lsm]_ | | ++ + +----------------------------------+-----------+ +| | | ``lsm.s+`` [#lsm]_ | Yes | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_LWT_IN`` | | ``lwt_in`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_LWT_OUT`` | | ``lwt_out`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_LWT_SEG6LOCAL`` | | ``lwt_seg6local`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_LWT_XMIT`` | | ``lwt_xmit`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_PERF_EVENT`` | | ``perf_event`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE`` | | ``raw_tp.w+`` [#rawtp]_ | | ++ + +----------------------------------+-----------+ +| | | ``raw_tracepoint.w+`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_RAW_TRACEPOINT`` | | ``raw_tp+`` [#rawtp]_ | | ++ + +----------------------------------+-----------+ +| | | ``raw_tracepoint+`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_SCHED_ACT`` | | ``action`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_SCHED_CLS`` | | ``classifier`` | | ++ + +----------------------------------+-----------+ +| | | ``tc`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_SK_LOOKUP`` | ``BPF_SK_LOOKUP`` | ``sk_lookup`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_SK_MSG`` | ``BPF_SK_MSG_VERDICT`` | ``sk_msg`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_SK_REUSEPORT`` | ``BPF_SK_REUSEPORT_SELECT_OR_MIGRATE`` | ``sk_reuseport/migrate`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_SK_REUSEPORT_SELECT`` | ``sk_reuseport`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_SK_SKB`` | | ``sk_skb`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_SK_SKB_STREAM_PARSER`` | ``sk_skb/stream_parser`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_SK_SKB_STREAM_VERDICT`` | ``sk_skb/stream_verdict`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_SOCKET_FILTER`` | | ``socket`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_SOCK_OPS`` | ``BPF_CGROUP_SOCK_OPS`` | ``sockops`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_STRUCT_OPS`` | | ``struct_ops+`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_SYSCALL`` | | ``syscall`` | Yes | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_TRACEPOINT`` | | ``tp+`` [#tp]_ | | ++ + +----------------------------------+-----------+ +| | | ``tracepoint+`` [#tp]_ | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_TRACING`` | ``BPF_MODIFY_RETURN`` | ``fmod_ret+`` [#fentry]_ | | ++ + +----------------------------------+-----------+ +| | | ``fmod_ret.s+`` [#fentry]_ | Yes | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_TRACE_FENTRY`` | ``fentry+`` [#fentry]_ | | ++ + +----------------------------------+-----------+ +| | | ``fentry.s+`` [#fentry]_ | Yes | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_TRACE_FEXIT`` | ``fexit+`` [#fentry]_ | | ++ + +----------------------------------+-----------+ +| | | ``fexit.s+`` [#fentry]_ | Yes | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_TRACE_ITER`` | ``iter+`` [#iter]_ | | ++ + +----------------------------------+-----------+ +| | | ``iter.s+`` [#iter]_ | Yes | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_TRACE_RAW_TP`` | ``tp_btf+`` [#fentry]_ | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ +| ``BPF_PROG_TYPE_XDP`` | ``BPF_XDP_CPUMAP`` | ``xdp.frags/cpumap`` | | ++ + +----------------------------------+-----------+ +| | | ``xdp/cpumap`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_XDP_DEVMAP`` | ``xdp.frags/devmap`` | | ++ + +----------------------------------+-----------+ +| | | ``xdp/devmap`` | | ++ +----------------------------------------+----------------------------------+-----------+ +| | ``BPF_XDP`` | ``xdp.frags`` | | ++ + +----------------------------------+-----------+ +| | | ``xdp`` | | ++-------------------------------------------+----------------------------------------+----------------------------------+-----------+ + + +.. rubric:: Footnotes + +.. [#fentry] The ``fentry`` attach format is ``fentry[.s]/``. +.. [#kprobe] The ``kprobe`` attach format is ``kprobe/[+]``. Valid + characters for ``function`` are ``a-zA-Z0-9_.`` and ``offset`` must be a valid + non-negative integer. +.. [#ksyscall] The ``ksyscall`` attach format is ``ksyscall/``. +.. [#uprobe] The ``uprobe`` attach format is ``uprobe[.s]/:[+]``. +.. [#usdt] The ``usdt`` attach format is ``usdt/::``. +.. [#kpmulti] The ``kprobe.multi`` attach format is ``kprobe.multi/`` where ``pattern`` + supports ``*`` and ``?`` wildcards. Valid characters for pattern are + ``a-zA-Z0-9_.*?``. +.. [#lsm] The ``lsm`` attachment format is ``lsm[.s]/``. +.. [#rawtp] The ``raw_tp`` attach format is ``raw_tracepoint[.w]/``. +.. [#tp] The ``tracepoint`` attach format is ``tracepoint//``. +.. [#iter] The ``iter`` attach format is ``iter[.s]/``. diff --git a/Documentation/bpf/programs.rst b/Documentation/bpf/programs.rst index 620eb667ac7a..c99000ab6d9b 100644 --- a/Documentation/bpf/programs.rst +++ b/Documentation/bpf/programs.rst @@ -7,3 +7,6 @@ Program Types :glob: prog_* + +For a list of all program types, see :ref:`program_types_and_elf` in +the :ref:`libbpf` documentation. From 3685b0dc0d02ad89a36893d9d6be1675dd40a5fd Mon Sep 17 00:00:00 2001 From: Maryam Tahhan Date: Wed, 23 Nov 2022 09:23:20 +0000 Subject: [PATCH 084/101] docs/bpf: Fix sphinx warnings for cpumap Sphinx version >=3.1 warns about duplicate function declarations in the CPUMAP documentation. This is because the function name is the same for kernel and user space BPF progs but the parameters and return types they take is what differs. This patch moves from using the ``c:function::`` directive to using the ``code-block:: c`` directive. The patches also fix the indentation for the text associated with the "new" code block delcarations. The missing support of c:namespace-push:: and c:namespace-pop:: directives by helper scripts for kernel documentation prevents using the ``c:function::`` directive with proper namespacing. Signed-off-by: Maryam Tahhan Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20221123092321.88558-2-mtahhan@redhat.com --- Documentation/bpf/map_cpumap.rst | 56 +++++++++++++++++++------------- 1 file changed, 34 insertions(+), 22 deletions(-) diff --git a/Documentation/bpf/map_cpumap.rst b/Documentation/bpf/map_cpumap.rst index 61a797a86342..923cfc8ab51f 100644 --- a/Documentation/bpf/map_cpumap.rst +++ b/Documentation/bpf/map_cpumap.rst @@ -30,29 +30,35 @@ Usage Kernel BPF ---------- -.. c:function:: +bpf_redirect_map() +^^^^^^^^^^^^^^^^^^ +.. code-block:: c + long bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags) - Redirect the packet to the endpoint referenced by ``map`` at index ``key``. - For ``BPF_MAP_TYPE_CPUMAP`` this map contains references to CPUs. +Redirect the packet to the endpoint referenced by ``map`` at index ``key``. +For ``BPF_MAP_TYPE_CPUMAP`` this map contains references to CPUs. - The lower two bits of ``flags`` are used as the return code if the map lookup - fails. This is so that the return value can be one of the XDP program return - codes up to ``XDP_TX``, as chosen by the caller. +The lower two bits of ``flags`` are used as the return code if the map lookup +fails. This is so that the return value can be one of the XDP program return +codes up to ``XDP_TX``, as chosen by the caller. -Userspace ---------- +User space +---------- .. note:: CPUMAP entries can only be updated/looked up/deleted from user space and not from an eBPF program. Trying to call these functions from a kernel eBPF program will result in the program failing to load and a verifier warning. -.. c:function:: +bpf_map_update_elem() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + int bpf_map_update_elem(int fd, const void *key, const void *value, __u64 flags); - CPU entries can be added or updated using the ``bpf_map_update_elem()`` - helper. This helper replaces existing elements atomically. The ``value`` parameter - can be ``struct bpf_cpumap_val``. +CPU entries can be added or updated using the ``bpf_map_update_elem()`` +helper. This helper replaces existing elements atomically. The ``value`` parameter +can be ``struct bpf_cpumap_val``. .. code-block:: c @@ -64,23 +70,29 @@ Userspace } bpf_prog; }; - The flags argument can be one of the following: +The flags argument can be one of the following: - BPF_ANY: Create a new element or update an existing element. - BPF_NOEXIST: Create a new element only if it did not exist. - BPF_EXIST: Update an existing element. -.. c:function:: +bpf_map_lookup_elem() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + int bpf_map_lookup_elem(int fd, const void *key, void *value); - CPU entries can be retrieved using the ``bpf_map_lookup_elem()`` - helper. +CPU entries can be retrieved using the ``bpf_map_lookup_elem()`` +helper. + +bpf_map_delete_elem() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c -.. c:function:: int bpf_map_delete_elem(int fd, const void *key); - CPU entries can be deleted using the ``bpf_map_delete_elem()`` - helper. This helper will return 0 on success, or negative error in case of - failure. +CPU entries can be deleted using the ``bpf_map_delete_elem()`` +helper. This helper will return 0 on success, or negative error in case of +failure. Examples ======== @@ -141,8 +153,8 @@ The following code snippet shows how to declare a ``BPF_MAP_TYPE_CPUMAP`` called return bpf_redirect_map(&cpu_map, cpu_dest, 0); } -Userspace ---------- +User space +---------- The following code snippet shows how to dynamically set the max_entries for a CPUMAP to the max number of cpus available on the system. From c645eee4d35b58bffc90ee086f7a087fa942fd52 Mon Sep 17 00:00:00 2001 From: Maryam Tahhan Date: Wed, 23 Nov 2022 09:23:21 +0000 Subject: [PATCH 085/101] docs/bpf: Fix sphinx warnings for devmap Sphinx version >=3.1 warns about duplicate function declarations in the DEVMAP documentation. This is because the function name is the same for kernel and user space BPF progs but the parameters and return types they take is what differs. This patch moves from using the ``c:function::`` directive to using the ``code-block:: c`` directive. The patches also fix the indentation for the text associated with the "new" code block delcarations. The missing support of c:namespace-push:: and c:namespace-pop:: directives by helper scripts for kernel documentation prevents using the ``c:function::`` directive with proper namespacing. Signed-off-by: Maryam Tahhan Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20221123092321.88558-3-mtahhan@redhat.com --- Documentation/bpf/map_devmap.rst | 68 ++++++++++++++++++++------------ 1 file changed, 42 insertions(+), 26 deletions(-) diff --git a/Documentation/bpf/map_devmap.rst b/Documentation/bpf/map_devmap.rst index f64da348dbfe..927312c7b8c8 100644 --- a/Documentation/bpf/map_devmap.rst +++ b/Documentation/bpf/map_devmap.rst @@ -29,8 +29,11 @@ Usage ===== Kernel BPF ---------- -.. c:function:: - long bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags) +bpf_redirect_map() +^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + long bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags) Redirect the packet to the endpoint referenced by ``map`` at index ``key``. For ``BPF_MAP_TYPE_DEVMAP`` and ``BPF_MAP_TYPE_DEVMAP_HASH`` this map contains @@ -56,26 +59,32 @@ lower bits of the ``flags`` argument if the map lookup fails. More information about redirection can be found :doc:`redirect` -.. c:function:: +bpf_map_lookup_elem() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + void *bpf_map_lookup_elem(struct bpf_map *map, const void *key) Net device entries can be retrieved using the ``bpf_map_lookup_elem()`` helper. -Userspace ---------- +User space +---------- .. note:: DEVMAP entries can only be updated/deleted from user space and not from an eBPF program. Trying to call these functions from a kernel eBPF program will result in the program failing to load and a verifier warning. -.. c:function:: +bpf_map_update_elem() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + int bpf_map_update_elem(int fd, const void *key, const void *value, __u64 flags); - Net device entries can be added or updated using the ``bpf_map_update_elem()`` - helper. This helper replaces existing elements atomically. The ``value`` parameter - can be ``struct bpf_devmap_val`` or a simple ``int ifindex`` for backwards - compatibility. +Net device entries can be added or updated using the ``bpf_map_update_elem()`` +helper. This helper replaces existing elements atomically. The ``value`` parameter +can be ``struct bpf_devmap_val`` or a simple ``int ifindex`` for backwards +compatibility. .. code-block:: c @@ -87,35 +96,42 @@ Userspace } bpf_prog; }; - The ``flags`` argument can be one of the following: - +The ``flags`` argument can be one of the following: - ``BPF_ANY``: Create a new element or update an existing element. - ``BPF_NOEXIST``: Create a new element only if it did not exist. - ``BPF_EXIST``: Update an existing element. - DEVMAPs can associate a program with a device entry by adding a ``bpf_prog.fd`` - to ``struct bpf_devmap_val``. Programs are run after ``XDP_REDIRECT`` and have - access to both Rx device and Tx device. The program associated with the ``fd`` - must have type XDP with expected attach type ``xdp_devmap``. - When a program is associated with a device index, the program is run on an - ``XDP_REDIRECT`` and before the buffer is added to the per-cpu queue. Examples - of how to attach/use xdp_devmap progs can be found in the kernel selftests: +DEVMAPs can associate a program with a device entry by adding a ``bpf_prog.fd`` +to ``struct bpf_devmap_val``. Programs are run after ``XDP_REDIRECT`` and have +access to both Rx device and Tx device. The program associated with the ``fd`` +must have type XDP with expected attach type ``xdp_devmap``. +When a program is associated with a device index, the program is run on an +``XDP_REDIRECT`` and before the buffer is added to the per-cpu queue. Examples +of how to attach/use xdp_devmap progs can be found in the kernel selftests: - - ``tools/testing/selftests/bpf/prog_tests/xdp_devmap_attach.c`` - - ``tools/testing/selftests/bpf/progs/test_xdp_with_devmap_helpers.c`` +- ``tools/testing/selftests/bpf/prog_tests/xdp_devmap_attach.c`` +- ``tools/testing/selftests/bpf/progs/test_xdp_with_devmap_helpers.c`` + +bpf_map_lookup_elem() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c .. c:function:: int bpf_map_lookup_elem(int fd, const void *key, void *value); - Net device entries can be retrieved using the ``bpf_map_lookup_elem()`` - helper. +Net device entries can be retrieved using the ``bpf_map_lookup_elem()`` +helper. + +bpf_map_delete_elem() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c .. c:function:: int bpf_map_delete_elem(int fd, const void *key); - Net device entries can be deleted using the ``bpf_map_delete_elem()`` - helper. This helper will return 0 on success, or negative error in case of - failure. +Net device entries can be deleted using the ``bpf_map_delete_elem()`` +helper. This helper will return 0 on success, or negative error in case of +failure. Examples ======== From 264c21867a0e1b9a820732ba7c0cf19c6784e5fe Mon Sep 17 00:00:00 2001 From: Donald Hunter Date: Wed, 23 Nov 2022 14:11:51 +0000 Subject: [PATCH 086/101] docs/bpf: Document BPF_MAP_TYPE_BLOOM_FILTER Add documentation for BPF_MAP_TYPE_BLOOM_FILTER including kernel BPF helper usage, userspace usage and examples. Signed-off-by: Donald Hunter Signed-off-by: Daniel Borkmann Acked-by: Joanne Koong Link: https://lore.kernel.org/bpf/20221123141151.54556-1-donald.hunter@gmail.com --- Documentation/bpf/map_bloom_filter.rst | 174 +++++++++++++++++++++++++ 1 file changed, 174 insertions(+) create mode 100644 Documentation/bpf/map_bloom_filter.rst diff --git a/Documentation/bpf/map_bloom_filter.rst b/Documentation/bpf/map_bloom_filter.rst new file mode 100644 index 000000000000..c82487f2fe0d --- /dev/null +++ b/Documentation/bpf/map_bloom_filter.rst @@ -0,0 +1,174 @@ +.. SPDX-License-Identifier: GPL-2.0-only +.. Copyright (C) 2022 Red Hat, Inc. + +========================= +BPF_MAP_TYPE_BLOOM_FILTER +========================= + +.. note:: + - ``BPF_MAP_TYPE_BLOOM_FILTER`` was introduced in kernel version 5.16 + +``BPF_MAP_TYPE_BLOOM_FILTER`` provides a BPF bloom filter map. Bloom +filters are a space-efficient probabilistic data structure used to +quickly test whether an element exists in a set. In a bloom filter, +false positives are possible whereas false negatives are not. + +The bloom filter map does not have keys, only values. When the bloom +filter map is created, it must be created with a ``key_size`` of 0. The +bloom filter map supports two operations: + +- push: adding an element to the map +- peek: determining whether an element is present in the map + +BPF programs must use ``bpf_map_push_elem`` to add an element to the +bloom filter map and ``bpf_map_peek_elem`` to query the map. These +operations are exposed to userspace applications using the existing +``bpf`` syscall in the following way: + +- ``BPF_MAP_UPDATE_ELEM`` -> push +- ``BPF_MAP_LOOKUP_ELEM`` -> peek + +The ``max_entries`` size that is specified at map creation time is used +to approximate a reasonable bitmap size for the bloom filter, and is not +otherwise strictly enforced. If the user wishes to insert more entries +into the bloom filter than ``max_entries``, this may lead to a higher +false positive rate. + +The number of hashes to use for the bloom filter is configurable using +the lower 4 bits of ``map_extra`` in ``union bpf_attr`` at map creation +time. If no number is specified, the default used will be 5 hash +functions. In general, using more hashes decreases both the false +positive rate and the speed of a lookup. + +It is not possible to delete elements from a bloom filter map. A bloom +filter map may be used as an inner map. The user is responsible for +synchronising concurrent updates and lookups to ensure no false negative +lookups occur. + +Usage +===== + +Kernel BPF +---------- + +bpf_map_push_elem() +~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + + long bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags) + +A ``value`` can be added to a bloom filter using the +``bpf_map_push_elem()`` helper. The ``flags`` parameter must be set to +``BPF_ANY`` when adding an entry to the bloom filter. This helper +returns ``0`` on success, or negative error in case of failure. + +bpf_map_peek_elem() +~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + + long bpf_map_peek_elem(struct bpf_map *map, void *value) + +The ``bpf_map_peek_elem()`` helper is used to determine whether +``value`` is present in the bloom filter map. This helper returns ``0`` +if ``value`` is probably present in the map, or ``-ENOENT`` if ``value`` +is definitely not present in the map. + +Userspace +--------- + +bpf_map_update_elem() +~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + + int bpf_map_update_elem (int fd, const void *key, const void *value, __u64 flags) + +A userspace program can add a ``value`` to a bloom filter using libbpf's +``bpf_map_update_elem`` function. The ``key`` parameter must be set to +``NULL`` and ``flags`` must be set to ``BPF_ANY``. Returns ``0`` on +success, or negative error in case of failure. + +bpf_map_lookup_elem() +~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + + int bpf_map_lookup_elem (int fd, const void *key, void *value) + +A userspace program can determine the presence of ``value`` in a bloom +filter using libbpf's ``bpf_map_lookup_elem`` function. The ``key`` +parameter must be set to ``NULL``. Returns ``0`` if ``value`` is +probably present in the map, or ``-ENOENT`` if ``value`` is definitely +not present in the map. + +Examples +======== + +Kernel BPF +---------- + +This snippet shows how to declare a bloom filter in a BPF program: + +.. code-block:: c + + struct { + __uint(type, BPF_MAP_TYPE_BLOOM_FILTER); + __type(value, __u32); + __uint(max_entries, 1000); + __uint(map_extra, 3); + } bloom_filter SEC(".maps"); + +This snippet shows how to determine presence of a value in a bloom +filter in a BPF program: + +.. code-block:: c + + void *lookup(__u32 key) + { + if (bpf_map_peek_elem(&bloom_filter, &key) == 0) { + /* Verify not a false positive and fetch an associated + * value using a secondary lookup, e.g. in a hash table + */ + return bpf_map_lookup_elem(&hash_table, &key); + } + return 0; + } + +Userspace +--------- + +This snippet shows how to use libbpf to create a bloom filter map from +userspace: + +.. code-block:: c + + int create_bloom() + { + LIBBPF_OPTS(bpf_map_create_opts, opts, + .map_extra = 3); /* number of hashes */ + + return bpf_map_create(BPF_MAP_TYPE_BLOOM_FILTER, + "ipv6_bloom", /* name */ + 0, /* key size, must be zero */ + sizeof(ipv6_addr), /* value size */ + 10000, /* max entries */ + &opts); /* create options */ + } + +This snippet shows how to add an element to a bloom filter from +userspace: + +.. code-block:: c + + int add_element(struct bpf_map *bloom_map, __u32 value) + { + int bloom_fd = bpf_map__fd(bloom_map); + return bpf_map_update_elem(bloom_fd, NULL, &value, BPF_ANY); + } + +References +========== + +https://lwn.net/ml/bpf/20210831225005.2762202-1-joannekoong@fb.com/ From f17472d4599697d701aa239b4c475a506bccfd19 Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Tue, 22 Nov 2022 19:54:22 -0800 Subject: [PATCH 087/101] bpf: Prevent decl_tag from being referenced in func_proto arg Syzkaller managed to hit another decl_tag issue: btf_func_proto_check kernel/bpf/btf.c:4506 [inline] btf_check_all_types kernel/bpf/btf.c:4734 [inline] btf_parse_type_sec+0x1175/0x1980 kernel/bpf/btf.c:4763 btf_parse kernel/bpf/btf.c:5042 [inline] btf_new_fd+0x65a/0xb00 kernel/bpf/btf.c:6709 bpf_btf_load+0x6f/0x90 kernel/bpf/syscall.c:4342 __sys_bpf+0x50a/0x6c0 kernel/bpf/syscall.c:5034 __do_sys_bpf kernel/bpf/syscall.c:5093 [inline] __se_sys_bpf kernel/bpf/syscall.c:5091 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5091 do_syscall_64+0x54/0x70 arch/x86/entry/common.c:48 This seems similar to commit ea68376c8bed ("bpf: prevent decl_tag from being referenced in func_proto") but for the argument. Reported-by: syzbot+8dd0551dda6020944c5d@syzkaller.appspotmail.com Signed-off-by: Stanislav Fomichev Signed-off-by: Daniel Borkmann Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20221123035422.872531-2-sdf@google.com --- kernel/bpf/btf.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 1a59cc7ad730..cb43cb842e16 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -4792,6 +4792,11 @@ static int btf_func_proto_check(struct btf_verifier_env *env, break; } + if (btf_type_is_resolve_source_only(arg_type)) { + btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1); + return -EINVAL; + } + if (args[i].name_off && (!btf_name_offset_valid(btf, args[i].name_off) || !btf_name_valid_identifier(btf, args[i].name_off))) { From 8e898aaa733eca61393fc036c8a4b5834fee5dd3 Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Tue, 22 Nov 2022 19:54:21 -0800 Subject: [PATCH 088/101] selftests/bpf: Add reproducer for decl_tag in func_proto argument It should trigger a WARN_ON_ONCE in btf_type_id_size: RIP: 0010:btf_type_id_size+0x8bd/0x940 kernel/bpf/btf.c:1952 btf_func_proto_check kernel/bpf/btf.c:4506 [inline] btf_check_all_types kernel/bpf/btf.c:4734 [inline] btf_parse_type_sec+0x1175/0x1980 kernel/bpf/btf.c:4763 btf_parse kernel/bpf/btf.c:5042 [inline] btf_new_fd+0x65a/0xb00 kernel/bpf/btf.c:6709 bpf_btf_load+0x6f/0x90 kernel/bpf/syscall.c:4342 __sys_bpf+0x50a/0x6c0 kernel/bpf/syscall.c:5034 __do_sys_bpf kernel/bpf/syscall.c:5093 [inline] __se_sys_bpf kernel/bpf/syscall.c:5091 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5091 do_syscall_64+0x54/0x70 arch/x86/entry/common.c:48 Signed-off-by: Stanislav Fomichev Signed-off-by: Daniel Borkmann Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20221123035422.872531-1-sdf@google.com --- tools/testing/selftests/bpf/prog_tests/btf.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/btf.c b/tools/testing/selftests/bpf/prog_tests/btf.c index 95a2b80f0d17..de1b5b9eb93a 100644 --- a/tools/testing/selftests/bpf/prog_tests/btf.c +++ b/tools/testing/selftests/bpf/prog_tests/btf.c @@ -3948,6 +3948,20 @@ static struct btf_raw_test raw_tests[] = { .btf_load_err = true, .err_str = "Invalid return type", }, +{ + .descr = "decl_tag test #17, func proto, argument", + .raw_types = { + BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_DECL_TAG, 0, 0), 4), (-1), /* [1] */ + BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 0), /* [2] */ + BTF_FUNC_PROTO_ENC(0, 1), /* [3] */ + BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 1), + BTF_VAR_ENC(NAME_TBD, 2, 0), /* [4] */ + BTF_END_RAW, + }, + BTF_STR_SEC("\0local\0tag1\0var"), + .btf_load_err = true, + .err_str = "Invalid arg#1", +}, { .descr = "type_tag test #1", .raw_types = { From 539886a32a6a4601241d928dc8b776b052c04ed0 Mon Sep 17 00:00:00 2001 From: Donald Hunter Date: Tue, 22 Nov 2022 14:39:33 +0000 Subject: [PATCH 089/101] docs/bpf: Fix sphinx warnings in BPF map docs Fix duplicate C declaration warnings when using sphinx >= 3.1. Reported-by: Akira Yokosawa Signed-off-by: Donald Hunter Signed-off-by: Daniel Borkmann Reviewed-by: Akira Yokosawa Link: https://lore.kernel.org/bpf/ed4dac84-1b12-5c58-e4de-93ab9ac67c09@gmail.com Link: https://lore.kernel.org/bpf/20221122143933.91321-1-donald.hunter@gmail.com --- Documentation/bpf/map_array.rst | 20 ++++++++++++--- Documentation/bpf/map_hash.rst | 33 ++++++++++++++++++++---- Documentation/bpf/map_lpm_trie.rst | 24 +++++++++++++++--- Documentation/bpf/map_of_maps.rst | 6 ++++- Documentation/bpf/map_queue_stack.rst | 36 ++++++++++++++++++++++----- 5 files changed, 99 insertions(+), 20 deletions(-) diff --git a/Documentation/bpf/map_array.rst b/Documentation/bpf/map_array.rst index 97bb80333254..f2f51a53e8ae 100644 --- a/Documentation/bpf/map_array.rst +++ b/Documentation/bpf/map_array.rst @@ -32,7 +32,11 @@ Usage Kernel BPF ---------- -.. c:function:: +bpf_map_lookup_elem() +~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + void *bpf_map_lookup_elem(struct bpf_map *map, const void *key) Array elements can be retrieved using the ``bpf_map_lookup_elem()`` helper. @@ -40,7 +44,11 @@ This helper returns a pointer into the array element, so to avoid data races with userspace reading the value, the user must use primitives like ``__sync_fetch_and_add()`` when updating the value in-place. -.. c:function:: +bpf_map_update_elem() +~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + long bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags) Array elements can be updated using the ``bpf_map_update_elem()`` helper. @@ -53,7 +61,7 @@ To clear an array element, you may use ``bpf_map_update_elem()`` to insert a zero value to that index. Per CPU Array -~~~~~~~~~~~~~ +------------- Values stored in ``BPF_MAP_TYPE_ARRAY`` can be accessed by multiple programs across different CPUs. To restrict storage to a single CPU, you may use a @@ -63,7 +71,11 @@ When using a ``BPF_MAP_TYPE_PERCPU_ARRAY`` the ``bpf_map_update_elem()`` and ``bpf_map_lookup_elem()`` helpers automatically access the slot for the current CPU. -.. c:function:: +bpf_map_lookup_percpu_elem() +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + void *bpf_map_lookup_percpu_elem(struct bpf_map *map, const void *key, u32 cpu) The ``bpf_map_lookup_percpu_elem()`` helper can be used to lookup the array diff --git a/Documentation/bpf/map_hash.rst b/Documentation/bpf/map_hash.rst index e85120878b27..8669426264c6 100644 --- a/Documentation/bpf/map_hash.rst +++ b/Documentation/bpf/map_hash.rst @@ -34,7 +34,14 @@ the ``BPF_F_NO_COMMON_LRU`` flag when calling ``bpf_map_create``. Usage ===== -.. c:function:: +Kernel BPF +---------- + +bpf_map_update_elem() +~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + long bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags) Hash entries can be added or updated using the ``bpf_map_update_elem()`` @@ -49,14 +56,22 @@ parameter can be used to control the update behaviour: ``bpf_map_update_elem()`` returns 0 on success, or negative error in case of failure. -.. c:function:: +bpf_map_lookup_elem() +~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + void *bpf_map_lookup_elem(struct bpf_map *map, const void *key) Hash entries can be retrieved using the ``bpf_map_lookup_elem()`` helper. This helper returns a pointer to the value associated with ``key``, or ``NULL`` if no entry was found. -.. c:function:: +bpf_map_delete_elem() +~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + long bpf_map_delete_elem(struct bpf_map *map, const void *key) Hash entries can be deleted using the ``bpf_map_delete_elem()`` @@ -70,7 +85,11 @@ For ``BPF_MAP_TYPE_PERCPU_HASH`` and ``BPF_MAP_TYPE_LRU_PERCPU_HASH`` the ``bpf_map_update_elem()`` and ``bpf_map_lookup_elem()`` helpers automatically access the hash slot for the current CPU. -.. c:function:: +bpf_map_lookup_percpu_elem() +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + void *bpf_map_lookup_percpu_elem(struct bpf_map *map, const void *key, u32 cpu) The ``bpf_map_lookup_percpu_elem()`` helper can be used to lookup the @@ -89,7 +108,11 @@ See ``tools/testing/selftests/bpf/progs/test_spin_lock.c``. Userspace --------- -.. c:function:: +bpf_map_get_next_key() +~~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + int bpf_map_get_next_key(int fd, const void *cur_key, void *next_key) In userspace, it is possible to iterate through the keys of a hash using diff --git a/Documentation/bpf/map_lpm_trie.rst b/Documentation/bpf/map_lpm_trie.rst index 31be1aa7ba2c..74d64a30f500 100644 --- a/Documentation/bpf/map_lpm_trie.rst +++ b/Documentation/bpf/map_lpm_trie.rst @@ -35,7 +35,11 @@ Usage Kernel BPF ---------- -.. c:function:: +bpf_map_lookup_elem() +~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + void *bpf_map_lookup_elem(struct bpf_map *map, const void *key) The longest prefix entry for a given data value can be found using the @@ -48,7 +52,11 @@ performing longest prefix lookups. For example, when searching for the longest prefix match for an IPv4 address, ``prefixlen`` should be set to ``32``. -.. c:function:: +bpf_map_update_elem() +~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + long bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags) Prefix entries can be added or updated using the ``bpf_map_update_elem()`` @@ -61,7 +69,11 @@ case of failure. The flags parameter must be one of BPF_ANY, BPF_NOEXIST or BPF_EXIST, but the value is ignored, giving BPF_ANY semantics. -.. c:function:: +bpf_map_delete_elem() +~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + long bpf_map_delete_elem(struct bpf_map *map, const void *key) Prefix entries can be deleted using the ``bpf_map_delete_elem()`` @@ -74,7 +86,11 @@ Userspace Access from userspace uses libbpf APIs with the same names as above, with the map identified by ``fd``. -.. c:function:: +bpf_map_get_next_key() +~~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + int bpf_map_get_next_key (int fd, const void *cur_key, void *next_key) A userspace program can iterate through the entries in an LPM trie using diff --git a/Documentation/bpf/map_of_maps.rst b/Documentation/bpf/map_of_maps.rst index 07212b9227a9..7b5617c2d017 100644 --- a/Documentation/bpf/map_of_maps.rst +++ b/Documentation/bpf/map_of_maps.rst @@ -45,7 +45,11 @@ Usage Kernel BPF Helper ----------------- -.. c:function:: +bpf_map_lookup_elem() +~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + void *bpf_map_lookup_elem(struct bpf_map *map, const void *key) Inner maps can be retrieved using the ``bpf_map_lookup_elem()`` helper. This diff --git a/Documentation/bpf/map_queue_stack.rst b/Documentation/bpf/map_queue_stack.rst index f20e31a647b9..8d14ed49d6e1 100644 --- a/Documentation/bpf/map_queue_stack.rst +++ b/Documentation/bpf/map_queue_stack.rst @@ -28,7 +28,11 @@ Usage Kernel BPF ---------- -.. c:function:: +bpf_map_push_elem() +~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + long bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags) An element ``value`` can be added to a queue or stack using the @@ -38,14 +42,22 @@ when the queue or stack is full, the oldest element will be removed to make room for ``value`` to be added. Returns ``0`` on success, or negative error in case of failure. -.. c:function:: +bpf_map_peek_elem() +~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + long bpf_map_peek_elem(struct bpf_map *map, void *value) This helper fetches an element ``value`` from a queue or stack without removing it. Returns ``0`` on success, or negative error in case of failure. -.. c:function:: +bpf_map_pop_elem() +~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + long bpf_map_pop_elem(struct bpf_map *map, void *value) This helper removes an element into ``value`` from a queue or @@ -55,7 +67,11 @@ stack. Returns ``0`` on success, or negative error in case of failure. Userspace --------- -.. c:function:: +bpf_map_update_elem() +~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + int bpf_map_update_elem (int fd, const void *key, const void *value, __u64 flags) A userspace program can push ``value`` onto a queue or stack using libbpf's @@ -64,7 +80,11 @@ A userspace program can push ``value`` onto a queue or stack using libbpf's same semantics as the ``bpf_map_push_elem`` kernel helper. Returns ``0`` on success, or negative error in case of failure. -.. c:function:: +bpf_map_lookup_elem() +~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + int bpf_map_lookup_elem (int fd, const void *key, void *value) A userspace program can peek at the ``value`` at the head of a queue or stack @@ -72,7 +92,11 @@ using the libbpf ``bpf_map_lookup_elem`` function. The ``key`` parameter must be set to ``NULL``. Returns ``0`` on success, or negative error in case of failure. -.. c:function:: +bpf_map_lookup_and_delete_elem() +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + int bpf_map_lookup_and_delete_elem (int fd, const void *key, void *value) A userspace program can pop a ``value`` from the head of a queue or stack using From 72b43bde38de4aa05e6a7fa12d7965f48180deb6 Mon Sep 17 00:00:00 2001 From: Ji Rongfeng Date: Fri, 18 Nov 2022 16:18:18 +0800 Subject: [PATCH 090/101] bpf: Update bpf_{g,s}etsockopt() documentation * append missing optnames to the end * simplify bpf_getsockopt()'s doc Signed-off-by: Ji Rongfeng Link: https://lore.kernel.org/r/DU0P192MB15479B86200B1216EC90E162D6099@DU0P192MB1547.EURP192.PROD.OUTLOOK.COM Signed-off-by: Martin KaFai Lau --- include/uapi/linux/bpf.h | 21 ++++++++++++--------- tools/include/uapi/linux/bpf.h | 23 +++++++++++++---------- 2 files changed, 25 insertions(+), 19 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index ab86145df760..f89de51a45db 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -2584,14 +2584,19 @@ union bpf_attr { * * **SOL_SOCKET**, which supports the following *optname*\ s: * **SO_RCVBUF**, **SO_SNDBUF**, **SO_MAX_PACING_RATE**, * **SO_PRIORITY**, **SO_RCVLOWAT**, **SO_MARK**, - * **SO_BINDTODEVICE**, **SO_KEEPALIVE**. + * **SO_BINDTODEVICE**, **SO_KEEPALIVE**, **SO_REUSEADDR**, + * **SO_REUSEPORT**, **SO_BINDTOIFINDEX**, **SO_TXREHASH**. * * **IPPROTO_TCP**, which supports the following *optname*\ s: * **TCP_CONGESTION**, **TCP_BPF_IW**, * **TCP_BPF_SNDCWND_CLAMP**, **TCP_SAVE_SYN**, * **TCP_KEEPIDLE**, **TCP_KEEPINTVL**, **TCP_KEEPCNT**, - * **TCP_SYNCNT**, **TCP_USER_TIMEOUT**, **TCP_NOTSENT_LOWAT**. + * **TCP_SYNCNT**, **TCP_USER_TIMEOUT**, **TCP_NOTSENT_LOWAT**, + * **TCP_NODELAY**, **TCP_MAXSEG**, **TCP_WINDOW_CLAMP**, + * **TCP_THIN_LINEAR_TIMEOUTS**, **TCP_BPF_DELACK_MAX**, + * **TCP_BPF_RTO_MIN**. * * **IPPROTO_IP**, which supports *optname* **IP_TOS**. - * * **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**. + * * **IPPROTO_IPV6**, which supports the following *optname*\ s: + * **IPV6_TCLASS**, **IPV6_AUTOFLOWLABEL**. * Return * 0 on success, or a negative error in case of failure. * @@ -2808,12 +2813,10 @@ union bpf_attr { * and **BPF_CGROUP_INET6_CONNECT**. * * This helper actually implements a subset of **getsockopt()**. - * It supports the following *level*\ s: - * - * * **IPPROTO_TCP**, which supports *optname* - * **TCP_CONGESTION**. - * * **IPPROTO_IP**, which supports *optname* **IP_TOS**. - * * **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**. + * It supports the same set of *optname*\ s that is supported by + * the **bpf_setsockopt**\ () helper. The exceptions are + * **TCP_BPF_*** is **bpf_setsockopt**\ () only and + * **TCP_SAVED_SYN** is **bpf_getsockopt**\ () only. * Return * 0 on success, or a negative error in case of failure. * diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 6580448e9f77..f89de51a45db 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -2584,14 +2584,19 @@ union bpf_attr { * * **SOL_SOCKET**, which supports the following *optname*\ s: * **SO_RCVBUF**, **SO_SNDBUF**, **SO_MAX_PACING_RATE**, * **SO_PRIORITY**, **SO_RCVLOWAT**, **SO_MARK**, - * **SO_BINDTODEVICE**, **SO_KEEPALIVE**. + * **SO_BINDTODEVICE**, **SO_KEEPALIVE**, **SO_REUSEADDR**, + * **SO_REUSEPORT**, **SO_BINDTOIFINDEX**, **SO_TXREHASH**. * * **IPPROTO_TCP**, which supports the following *optname*\ s: * **TCP_CONGESTION**, **TCP_BPF_IW**, * **TCP_BPF_SNDCWND_CLAMP**, **TCP_SAVE_SYN**, * **TCP_KEEPIDLE**, **TCP_KEEPINTVL**, **TCP_KEEPCNT**, - * **TCP_SYNCNT**, **TCP_USER_TIMEOUT**, **TCP_NOTSENT_LOWAT**. + * **TCP_SYNCNT**, **TCP_USER_TIMEOUT**, **TCP_NOTSENT_LOWAT**, + * **TCP_NODELAY**, **TCP_MAXSEG**, **TCP_WINDOW_CLAMP**, + * **TCP_THIN_LINEAR_TIMEOUTS**, **TCP_BPF_DELACK_MAX**, + * **TCP_BPF_RTO_MIN**. * * **IPPROTO_IP**, which supports *optname* **IP_TOS**. - * * **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**. + * * **IPPROTO_IPV6**, which supports the following *optname*\ s: + * **IPV6_TCLASS**, **IPV6_AUTOFLOWLABEL**. * Return * 0 on success, or a negative error in case of failure. * @@ -2647,7 +2652,7 @@ union bpf_attr { * Return * 0 on success, or a negative error in case of failure. * - * long bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags) + * long bpf_redirect_map(struct bpf_map *map, u64 key, u64 flags) * Description * Redirect the packet to the endpoint referenced by *map* at * index *key*. Depending on its type, this *map* can contain @@ -2808,12 +2813,10 @@ union bpf_attr { * and **BPF_CGROUP_INET6_CONNECT**. * * This helper actually implements a subset of **getsockopt()**. - * It supports the following *level*\ s: - * - * * **IPPROTO_TCP**, which supports *optname* - * **TCP_CONGESTION**. - * * **IPPROTO_IP**, which supports *optname* **IP_TOS**. - * * **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**. + * It supports the same set of *optname*\ s that is supported by + * the **bpf_setsockopt**\ () helper. The exceptions are + * **TCP_BPF_*** is **bpf_setsockopt**\ () only and + * **TCP_SAVED_SYN** is **bpf_getsockopt**\ () only. * Return * 0 on success, or a negative error in case of failure. * From 5bad3587b7a292148cea10185cd8770baaeb7445 Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Wed, 23 Nov 2022 16:28:38 -0800 Subject: [PATCH 091/101] bpf: Unify and simplify btf_func_proto_check error handling Replace 'err = x; break;' with 'return x;'. Suggested-by: Daniel Borkmann Signed-off-by: Stanislav Fomichev Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20221124002838.2700179-1-sdf@google.com --- kernel/bpf/btf.c | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index cb43cb842e16..9dbfda2b5c6c 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -4779,7 +4779,6 @@ static int btf_func_proto_check(struct btf_verifier_env *env, nr_args--; } - err = 0; for (i = 0; i < nr_args; i++) { const struct btf_type *arg_type; u32 arg_type_id; @@ -4788,8 +4787,7 @@ static int btf_func_proto_check(struct btf_verifier_env *env, arg_type = btf_type_by_id(btf, arg_type_id); if (!arg_type) { btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1); - err = -EINVAL; - break; + return -EINVAL; } if (btf_type_is_resolve_source_only(arg_type)) { @@ -4802,25 +4800,23 @@ static int btf_func_proto_check(struct btf_verifier_env *env, !btf_name_valid_identifier(btf, args[i].name_off))) { btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1); - err = -EINVAL; - break; + return -EINVAL; } if (btf_type_needs_resolve(arg_type) && !env_type_is_resolved(env, arg_type_id)) { err = btf_resolve(env, arg_type, arg_type_id); if (err) - break; + return err; } if (!btf_type_id_size(btf, &arg_type_id, NULL)) { btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1); - err = -EINVAL; - break; + return -EINVAL; } } - return err; + return 0; } static int btf_func_check(struct btf_verifier_env *env, From 3f0e6f2b41d35d4446160c745e8f09037447dd8f Mon Sep 17 00:00:00 2001 From: David Vernet Date: Tue, 22 Nov 2022 08:52:59 -0600 Subject: [PATCH 092/101] bpf: Add bpf_task_from_pid() kfunc Callers can currently store tasks as kptrs using bpf_task_acquire(), bpf_task_kptr_get(), and bpf_task_release(). These are useful if a caller already has a struct task_struct *, but there may be some callers who only have a pid, and want to look up the associated struct task_struct * from that to e.g. find task->comm. This patch therefore adds a new bpf_task_from_pid() kfunc which allows BPF programs to get a struct task_struct * kptr from a pid. Signed-off-by: David Vernet Link: https://lore.kernel.org/r/20221122145300.251210-2-void@manifault.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/helpers.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index da2681ebb7c3..2299bb0d89e5 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1959,6 +1959,25 @@ struct cgroup *bpf_cgroup_ancestor(struct cgroup *cgrp, int level) } #endif /* CONFIG_CGROUPS */ +/** + * bpf_task_from_pid - Find a struct task_struct from its pid by looking it up + * in the root pid namespace idr. If a task is returned, it must either be + * stored in a map, or released with bpf_task_release(). + * @pid: The pid of the task being looked up. + */ +struct task_struct *bpf_task_from_pid(s32 pid) +{ + struct task_struct *p; + + rcu_read_lock(); + p = find_task_by_pid_ns(pid, &init_pid_ns); + if (p) + bpf_task_acquire(p); + rcu_read_unlock(); + + return p; +} + void *bpf_cast_to_kern_ctx(void *obj) { return obj; @@ -1984,13 +2003,13 @@ BTF_ID_FLAGS(func, bpf_list_pop_back, KF_ACQUIRE | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_task_acquire, KF_ACQUIRE | KF_TRUSTED_ARGS) BTF_ID_FLAGS(func, bpf_task_kptr_get, KF_ACQUIRE | KF_KPTR_GET | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_task_release, KF_RELEASE) - #ifdef CONFIG_CGROUPS BTF_ID_FLAGS(func, bpf_cgroup_acquire, KF_ACQUIRE | KF_TRUSTED_ARGS) BTF_ID_FLAGS(func, bpf_cgroup_kptr_get, KF_ACQUIRE | KF_KPTR_GET | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_cgroup_release, KF_RELEASE) BTF_ID_FLAGS(func, bpf_cgroup_ancestor, KF_ACQUIRE | KF_TRUSTED_ARGS | KF_RET_NULL) #endif +BTF_ID_FLAGS(func, bpf_task_from_pid, KF_ACQUIRE | KF_RET_NULL) BTF_SET8_END(generic_btf_ids) static const struct btf_kfunc_id_set generic_kfunc_set = { From f471748b7fe5ab7ec6de4cbadffabfa7bb5b6240 Mon Sep 17 00:00:00 2001 From: David Vernet Date: Tue, 22 Nov 2022 08:53:00 -0600 Subject: [PATCH 093/101] selftests/bpf: Add selftests for bpf_task_from_pid() Add some selftest testcases that validate the expected behavior of the bpf_task_from_pid() kfunc that was added in the prior patch. Signed-off-by: David Vernet Link: https://lore.kernel.org/r/20221122145300.251210-3-void@manifault.com Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/prog_tests/task_kfunc.c | 4 + .../selftests/bpf/progs/task_kfunc_common.h | 1 + .../selftests/bpf/progs/task_kfunc_failure.c | 13 ++++ .../selftests/bpf/progs/task_kfunc_success.c | 73 +++++++++++++++++++ 4 files changed, 91 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/task_kfunc.c b/tools/testing/selftests/bpf/prog_tests/task_kfunc.c index 4994fe6092cc..ffd8ef4303c8 100644 --- a/tools/testing/selftests/bpf/prog_tests/task_kfunc.c +++ b/tools/testing/selftests/bpf/prog_tests/task_kfunc.c @@ -78,6 +78,9 @@ static const char * const success_tests[] = { "test_task_xchg_release", "test_task_get_release", "test_task_current_acquire_release", + "test_task_from_pid_arg", + "test_task_from_pid_current", + "test_task_from_pid_invalid", }; static struct { @@ -99,6 +102,7 @@ static struct { {"task_kfunc_release_fp", "arg#0 pointer type STRUCT task_struct must point"}, {"task_kfunc_release_null", "arg#0 is ptr_or_null_ expected ptr_ or socket"}, {"task_kfunc_release_unacquired", "release kernel function bpf_task_release expects"}, + {"task_kfunc_from_pid_no_null_check", "arg#0 is ptr_or_null_ expected ptr_ or socket"}, }; static void verify_fail(const char *prog_name, const char *expected_err_msg) diff --git a/tools/testing/selftests/bpf/progs/task_kfunc_common.h b/tools/testing/selftests/bpf/progs/task_kfunc_common.h index 160d6dde00be..c0ffd171743e 100644 --- a/tools/testing/selftests/bpf/progs/task_kfunc_common.h +++ b/tools/testing/selftests/bpf/progs/task_kfunc_common.h @@ -23,6 +23,7 @@ struct hash_map { struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym; struct task_struct *bpf_task_kptr_get(struct task_struct **pp) __ksym; void bpf_task_release(struct task_struct *p) __ksym; +struct task_struct *bpf_task_from_pid(s32 pid) __ksym; static inline struct __tasks_kfunc_map_value *tasks_kfunc_map_value_lookup(struct task_struct *p) { diff --git a/tools/testing/selftests/bpf/progs/task_kfunc_failure.c b/tools/testing/selftests/bpf/progs/task_kfunc_failure.c index 93e934ddfcb6..e310473190d5 100644 --- a/tools/testing/selftests/bpf/progs/task_kfunc_failure.c +++ b/tools/testing/selftests/bpf/progs/task_kfunc_failure.c @@ -258,3 +258,16 @@ int BPF_PROG(task_kfunc_release_unacquired, struct task_struct *task, u64 clone_ return 0; } + +SEC("tp_btf/task_newtask") +int BPF_PROG(task_kfunc_from_pid_no_null_check, struct task_struct *task, u64 clone_flags) +{ + struct task_struct *acquired; + + acquired = bpf_task_from_pid(task->pid); + + /* Releasing bpf_task_from_pid() lookup without a NULL check. */ + bpf_task_release(acquired); + + return 0; +} diff --git a/tools/testing/selftests/bpf/progs/task_kfunc_success.c b/tools/testing/selftests/bpf/progs/task_kfunc_success.c index be4534b5ba2e..60c7ead41cfc 100644 --- a/tools/testing/selftests/bpf/progs/task_kfunc_success.c +++ b/tools/testing/selftests/bpf/progs/task_kfunc_success.c @@ -147,3 +147,76 @@ int BPF_PROG(test_task_current_acquire_release, struct task_struct *task, u64 cl return 0; } + +static void lookup_compare_pid(const struct task_struct *p) +{ + struct task_struct *acquired; + + acquired = bpf_task_from_pid(p->pid); + if (!acquired) { + err = 1; + return; + } + + if (acquired->pid != p->pid) + err = 2; + bpf_task_release(acquired); +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(test_task_from_pid_arg, struct task_struct *task, u64 clone_flags) +{ + struct task_struct *acquired; + + if (!is_test_kfunc_task()) + return 0; + + lookup_compare_pid(task); + return 0; +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(test_task_from_pid_current, struct task_struct *task, u64 clone_flags) +{ + struct task_struct *current, *acquired; + + if (!is_test_kfunc_task()) + return 0; + + lookup_compare_pid(bpf_get_current_task_btf()); + return 0; +} + +static int is_pid_lookup_valid(s32 pid) +{ + struct task_struct *acquired; + + acquired = bpf_task_from_pid(pid); + if (acquired) { + bpf_task_release(acquired); + return 1; + } + + return 0; +} + +SEC("tp_btf/task_newtask") +int BPF_PROG(test_task_from_pid_invalid, struct task_struct *task, u64 clone_flags) +{ + struct task_struct *acquired; + + if (!is_test_kfunc_task()) + return 0; + + if (is_pid_lookup_valid(-1)) { + err = 1; + return 0; + } + + if (is_pid_lookup_valid(0xcafef00d)) { + err = 2; + return 0; + } + + return 0; +} From 5a0f663f0189cf9e031e444f97c029717a99548d Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Wed, 23 Nov 2022 21:32:06 -0800 Subject: [PATCH 094/101] compiler_types: Define __rcu as __attribute__((btf_type_tag("rcu"))) Currently, without rcu attribute info in BTF, the verifier treats rcu tagged pointer as a normal pointer. This might be a problem for sleepable program where rcu_read_lock()/unlock() is not available. For example, for a sleepable fentry program, if rcu protected memory access is interleaved with a sleepable helper/kfunc, it is possible the memory access after the sleepable helper/kfunc might be invalid since the object might have been freed then. To prevent such cases, introducing rcu tagging for memory accesses in verifier can help to reject such programs. To enable rcu tagging in BTF, during kernel compilation, define __rcu as attribute btf_type_tag("rcu") so __rcu information can be preserved in dwarf and btf, and later can be used for bpf prog verification. Acked-by: KP Singh Acked-by: Martin KaFai Lau Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20221124053206.2373141-1-yhs@fb.com Signed-off-by: Alexei Starovoitov --- include/linux/compiler_types.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index eb0466236661..7c1afe0f4129 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -49,7 +49,8 @@ static inline void __chk_io_ptr(const volatile void __iomem *ptr) { } # endif # define __iomem # define __percpu BTF_TYPE_TAG(percpu) -# define __rcu +# define __rcu BTF_TYPE_TAG(rcu) + # define __chk_user_ptr(x) (void)0 # define __chk_io_ptr(x) (void)0 /* context/locking */ From 01685c5bddaa6df3d662c8afed5e5289fcc68e5a Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Wed, 23 Nov 2022 21:32:11 -0800 Subject: [PATCH 095/101] bpf: Introduce might_sleep field in bpf_func_proto Introduce bpf_func_proto->might_sleep to indicate a particular helper might sleep. This will make later check whether a helper might be sleepable or not easier. Acked-by: Martin KaFai Lau Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20221124053211.2373553-1-yhs@fb.com Signed-off-by: Alexei Starovoitov --- include/linux/bpf.h | 1 + kernel/bpf/bpf_lsm.c | 6 ++++-- kernel/bpf/helpers.c | 2 ++ kernel/bpf/verifier.c | 5 +++++ kernel/trace/bpf_trace.c | 4 ++-- 5 files changed, 14 insertions(+), 4 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index c9eafa67f2a2..43fd7eeeeabb 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -682,6 +682,7 @@ struct bpf_func_proto { u64 (*func)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); bool gpl_only; bool pkt_access; + bool might_sleep; enum bpf_return_type ret_type; union { struct { diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c index d6c9b3705f24..ae0267f150b5 100644 --- a/kernel/bpf/bpf_lsm.c +++ b/kernel/bpf/bpf_lsm.c @@ -151,6 +151,7 @@ BTF_ID_LIST_SINGLE(bpf_ima_inode_hash_btf_ids, struct, inode) static const struct bpf_func_proto bpf_ima_inode_hash_proto = { .func = bpf_ima_inode_hash, .gpl_only = false, + .might_sleep = true, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_BTF_ID, .arg1_btf_id = &bpf_ima_inode_hash_btf_ids[0], @@ -169,6 +170,7 @@ BTF_ID_LIST_SINGLE(bpf_ima_file_hash_btf_ids, struct, file) static const struct bpf_func_proto bpf_ima_file_hash_proto = { .func = bpf_ima_file_hash, .gpl_only = false, + .might_sleep = true, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_BTF_ID, .arg1_btf_id = &bpf_ima_file_hash_btf_ids[0], @@ -221,9 +223,9 @@ bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) case BPF_FUNC_bprm_opts_set: return &bpf_bprm_opts_set_proto; case BPF_FUNC_ima_inode_hash: - return prog->aux->sleepable ? &bpf_ima_inode_hash_proto : NULL; + return &bpf_ima_inode_hash_proto; case BPF_FUNC_ima_file_hash: - return prog->aux->sleepable ? &bpf_ima_file_hash_proto : NULL; + return &bpf_ima_file_hash_proto; case BPF_FUNC_get_attach_cookie: return bpf_prog_has_trampoline(prog) ? &bpf_get_attach_cookie_proto : NULL; #ifdef CONFIG_NET diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 2299bb0d89e5..9296b654dbd7 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -661,6 +661,7 @@ BPF_CALL_3(bpf_copy_from_user, void *, dst, u32, size, const struct bpf_func_proto bpf_copy_from_user_proto = { .func = bpf_copy_from_user, .gpl_only = false, + .might_sleep = true, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_UNINIT_MEM, .arg2_type = ARG_CONST_SIZE_OR_ZERO, @@ -691,6 +692,7 @@ BPF_CALL_5(bpf_copy_from_user_task, void *, dst, u32, size, const struct bpf_func_proto bpf_copy_from_user_task_proto = { .func = bpf_copy_from_user_task, .gpl_only = true, + .might_sleep = true, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_UNINIT_MEM, .arg2_type = ARG_CONST_SIZE_OR_ZERO, diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 9528a066cfa5..068cc885903c 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -7516,6 +7516,11 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn return -EINVAL; } + if (!env->prog->aux->sleepable && fn->might_sleep) { + verbose(env, "helper call might sleep in a non-sleepable prog\n"); + return -EINVAL; + } + /* With LD_ABS/IND some JITs save/restore skb from r1. */ changes_data = bpf_helper_changes_pkt_data(fn->func); if (changes_data && fn->arg1_type != ARG_PTR_TO_CTX) { diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 5b9008bc597b..3bbd3f0c810c 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1485,9 +1485,9 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) case BPF_FUNC_get_task_stack: return &bpf_get_task_stack_proto; case BPF_FUNC_copy_from_user: - return prog->aux->sleepable ? &bpf_copy_from_user_proto : NULL; + return &bpf_copy_from_user_proto; case BPF_FUNC_copy_from_user_task: - return prog->aux->sleepable ? &bpf_copy_from_user_task_proto : NULL; + return &bpf_copy_from_user_task_proto; case BPF_FUNC_snprintf_btf: return &bpf_snprintf_btf_proto; case BPF_FUNC_per_cpu_ptr: From 9bb00b2895cbfe0ad410457b605d0a72524168c1 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Wed, 23 Nov 2022 21:32:17 -0800 Subject: [PATCH 096/101] bpf: Add kfunc bpf_rcu_read_lock/unlock() Add two kfunc's bpf_rcu_read_lock() and bpf_rcu_read_unlock(). These two kfunc's can be used for all program types. The following is an example about how rcu pointer are used w.r.t. bpf_rcu_read_lock()/bpf_rcu_read_unlock(). struct task_struct { ... struct task_struct *last_wakee; struct task_struct __rcu *real_parent; ... }; Let us say prog does 'task = bpf_get_current_task_btf()' to get a 'task' pointer. The basic rules are: - 'real_parent = task->real_parent' should be inside bpf_rcu_read_lock region. This is to simulate rcu_dereference() operation. The 'real_parent' is marked as MEM_RCU only if (1). task->real_parent is inside bpf_rcu_read_lock region, and (2). task is a trusted ptr. So MEM_RCU marked ptr can be 'trusted' inside the bpf_rcu_read_lock region. - 'last_wakee = real_parent->last_wakee' should be inside bpf_rcu_read_lock region since it tries to access rcu protected memory. - the ptr 'last_wakee' will be marked as PTR_UNTRUSTED since in general it is not clear whether the object pointed by 'last_wakee' is valid or not even inside bpf_rcu_read_lock region. The verifier will reset all rcu pointer register states to untrusted at bpf_rcu_read_unlock() kfunc call site, so any such rcu pointer won't be trusted any more outside the bpf_rcu_read_lock() region. The current implementation does not support nested rcu read lock region in the prog. Acked-by: Martin KaFai Lau Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20221124053217.2373910-1-yhs@fb.com Signed-off-by: Alexei Starovoitov --- include/linux/bpf.h | 3 + include/linux/bpf_verifier.h | 5 +- kernel/bpf/btf.c | 3 + kernel/bpf/helpers.c | 12 +++ kernel/bpf/verifier.c | 162 ++++++++++++++++++++++++++++------- 5 files changed, 155 insertions(+), 30 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 43fd7eeeeabb..c6aa6912ea16 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -572,6 +572,9 @@ enum bpf_type_flag { */ PTR_TRUSTED = BIT(12 + BPF_BASE_TYPE_BITS), + /* MEM is tagged with rcu and memory access needs rcu_read_lock protection. */ + MEM_RCU = BIT(13 + BPF_BASE_TYPE_BITS), + __BPF_TYPE_FLAG_MAX, __BPF_TYPE_LAST_FLAG = __BPF_TYPE_FLAG_MAX - 1, }; diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 545152ac136c..c05aa6e1f6f5 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -344,6 +344,7 @@ struct bpf_verifier_state { u32 id; } active_lock; bool speculative; + bool active_rcu_lock; /* first and last insn idx of this verifier state */ u32 first_insn_idx; @@ -445,6 +446,7 @@ struct bpf_insn_aux_data { u32 seen; /* this insn was processed by the verifier at env->pass_cnt */ bool sanitize_stack_spill; /* subject to Spectre v4 sanitation */ bool zext_dst; /* this insn zero extends dst reg */ + bool storage_get_func_atomic; /* bpf_*_storage_get() with atomic memory alloc */ u8 alu_state; /* used in combination with alu_limit */ /* below fields are initialized once */ @@ -534,6 +536,7 @@ struct bpf_verifier_env { bool bypass_spec_v1; bool bypass_spec_v4; bool seen_direct_write; + bool rcu_tag_supported; struct bpf_insn_aux_data *insn_aux_data; /* array of per-insn state */ const struct bpf_line_info *prev_linfo; struct bpf_verifier_log log; @@ -680,7 +683,7 @@ static inline bool bpf_prog_check_recur(const struct bpf_prog *prog) } } -#define BPF_REG_TRUSTED_MODIFIERS (MEM_ALLOC | PTR_TRUSTED) +#define BPF_REG_TRUSTED_MODIFIERS (MEM_ALLOC | MEM_RCU | PTR_TRUSTED) static inline bool bpf_type_has_unsafe_modifiers(u32 type) { diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 9dbfda2b5c6c..bd3369100239 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -6238,6 +6238,9 @@ error: /* check __percpu tag */ if (strcmp(tag_value, "percpu") == 0) tmp_flag = MEM_PERCPU; + /* check __rcu tag */ + if (strcmp(tag_value, "rcu") == 0) + tmp_flag = MEM_RCU; } stype = btf_type_skip_modifiers(btf, mtype->type, &id); diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 9296b654dbd7..a5a511430f2a 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1990,6 +1990,16 @@ void *bpf_rdonly_cast(void *obj__ign, u32 btf_id__k) return obj__ign; } +void bpf_rcu_read_lock(void) +{ + rcu_read_lock(); +} + +void bpf_rcu_read_unlock(void) +{ + rcu_read_unlock(); +} + __diag_pop(); BTF_SET8_START(generic_btf_ids) @@ -2031,6 +2041,8 @@ BTF_ID(func, bpf_cgroup_release) BTF_SET8_START(common_btf_ids) BTF_ID_FLAGS(func, bpf_cast_to_kern_ctx) BTF_ID_FLAGS(func, bpf_rdonly_cast) +BTF_ID_FLAGS(func, bpf_rcu_read_lock) +BTF_ID_FLAGS(func, bpf_rcu_read_unlock) BTF_SET8_END(common_btf_ids) static const struct btf_kfunc_id_set common_kfunc_set = { diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 068cc885903c..f4500479f1c2 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -527,6 +527,14 @@ static bool is_callback_calling_function(enum bpf_func_id func_id) func_id == BPF_FUNC_user_ringbuf_drain; } +static bool is_storage_get_function(enum bpf_func_id func_id) +{ + return func_id == BPF_FUNC_sk_storage_get || + func_id == BPF_FUNC_inode_storage_get || + func_id == BPF_FUNC_task_storage_get || + func_id == BPF_FUNC_cgrp_storage_get; +} + static bool helper_multiple_ref_obj_use(enum bpf_func_id func_id, const struct bpf_map *map) { @@ -589,11 +597,12 @@ static const char *reg_type_str(struct bpf_verifier_env *env, strncpy(postfix, "_or_null", 16); } - snprintf(prefix, sizeof(prefix), "%s%s%s%s%s%s", + snprintf(prefix, sizeof(prefix), "%s%s%s%s%s%s%s", type & MEM_RDONLY ? "rdonly_" : "", type & MEM_RINGBUF ? "ringbuf_" : "", type & MEM_USER ? "user_" : "", type & MEM_PERCPU ? "percpu_" : "", + type & MEM_RCU ? "rcu_" : "", type & PTR_UNTRUSTED ? "untrusted_" : "", type & PTR_TRUSTED ? "trusted_" : "" ); @@ -1220,6 +1229,7 @@ static int copy_verifier_state(struct bpf_verifier_state *dst_state, dst_state->frame[i] = NULL; } dst_state->speculative = src->speculative; + dst_state->active_rcu_lock = src->active_rcu_lock; dst_state->curframe = src->curframe; dst_state->active_lock.ptr = src->active_lock.ptr; dst_state->active_lock.id = src->active_lock.id; @@ -4258,6 +4268,25 @@ static bool is_flow_key_reg(struct bpf_verifier_env *env, int regno) return reg->type == PTR_TO_FLOW_KEYS; } +static bool is_trusted_reg(const struct bpf_reg_state *reg) +{ + /* A referenced register is always trusted. */ + if (reg->ref_obj_id) + return true; + + /* If a register is not referenced, it is trusted if it has the + * MEM_ALLOC, MEM_RCU or PTR_TRUSTED type modifiers, and no others. Some of the + * other type modifiers may be safe, but we elect to take an opt-in + * approach here as some (e.g. PTR_UNTRUSTED and PTR_MAYBE_NULL) are + * not. + * + * Eventually, we should make PTR_TRUSTED the single source of truth + * for whether a register is trusted. + */ + return type_flag(reg->type) & BPF_REG_TRUSTED_MODIFIERS && + !bpf_type_has_unsafe_modifiers(reg->type); +} + static int check_pkt_ptr_alignment(struct bpf_verifier_env *env, const struct bpf_reg_state *reg, int off, int size, bool strict) @@ -4737,9 +4766,28 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env, if (type_flag(reg->type) & PTR_UNTRUSTED) flag |= PTR_UNTRUSTED; - /* Any pointer obtained from walking a trusted pointer is no longer trusted. */ + /* By default any pointer obtained from walking a trusted pointer is + * no longer trusted except the rcu case below. + */ flag &= ~PTR_TRUSTED; + if (flag & MEM_RCU) { + /* Mark value register as MEM_RCU only if it is protected by + * bpf_rcu_read_lock() and the ptr reg is trusted. MEM_RCU + * itself can already indicate trustedness inside the rcu + * read lock region. Also mark it as PTR_TRUSTED. + */ + if (!env->cur_state->active_rcu_lock || !is_trusted_reg(reg)) + flag &= ~MEM_RCU; + else + flag |= PTR_TRUSTED; + } else if (reg->type & MEM_RCU) { + /* ptr (reg) is marked as MEM_RCU, but the struct field is not tagged + * with __rcu. Mark the flag as PTR_UNTRUSTED conservatively. + */ + flag |= PTR_UNTRUSTED; + } + if (atype == BPF_READ && value_regno >= 0) mark_btf_ld_reg(env, regs, value_regno, ret, reg->btf, btf_id, flag); @@ -5897,6 +5945,7 @@ static const struct bpf_reg_types btf_ptr_types = { .types = { PTR_TO_BTF_ID, PTR_TO_BTF_ID | PTR_TRUSTED, + PTR_TO_BTF_ID | MEM_RCU | PTR_TRUSTED, }, }; static const struct bpf_reg_types percpu_btf_ptr_types = { @@ -6075,6 +6124,7 @@ int check_func_arg_reg_off(struct bpf_verifier_env *env, case PTR_TO_BTF_ID: case PTR_TO_BTF_ID | MEM_ALLOC: case PTR_TO_BTF_ID | PTR_TRUSTED: + case PTR_TO_BTF_ID | MEM_RCU | PTR_TRUSTED: case PTR_TO_BTF_ID | MEM_ALLOC | PTR_TRUSTED: /* When referenced PTR_TO_BTF_ID is passed to release function, * it's fixed offset must be 0. In the other cases, fixed offset @@ -7539,6 +7589,17 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn return err; } + if (env->cur_state->active_rcu_lock) { + if (fn->might_sleep) { + verbose(env, "sleepable helper %s#%d in rcu_read_lock region\n", + func_id_name(func_id), func_id); + return -EINVAL; + } + + if (env->prog->aux->sleepable && is_storage_get_function(func_id)) + env->insn_aux_data[insn_idx].storage_get_func_atomic = true; + } + meta.func_id = func_id; /* check args */ for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) { @@ -7966,25 +8027,6 @@ static bool is_kfunc_arg_kptr_get(struct bpf_kfunc_call_arg_meta *meta, int arg) return arg == 0 && (meta->kfunc_flags & KF_KPTR_GET); } -static bool is_trusted_reg(const struct bpf_reg_state *reg) -{ - /* A referenced register is always trusted. */ - if (reg->ref_obj_id) - return true; - - /* If a register is not referenced, it is trusted if it has either the - * MEM_ALLOC or PTR_TRUSTED type modifiers, and no others. Some of the - * other type modifiers may be safe, but we elect to take an opt-in - * approach here as some (e.g. PTR_UNTRUSTED and PTR_MAYBE_NULL) are - * not. - * - * Eventually, we should make PTR_TRUSTED the single source of truth - * for whether a register is trusted. - */ - return type_flag(reg->type) & BPF_REG_TRUSTED_MODIFIERS && - !bpf_type_has_unsafe_modifiers(reg->type); -} - static bool __kfunc_param_match_suffix(const struct btf *btf, const struct btf_param *arg, const char *suffix) @@ -8163,6 +8205,8 @@ enum special_kfunc_type { KF_bpf_list_pop_back, KF_bpf_cast_to_kern_ctx, KF_bpf_rdonly_cast, + KF_bpf_rcu_read_lock, + KF_bpf_rcu_read_unlock, }; BTF_SET_START(special_kfunc_set) @@ -8185,6 +8229,18 @@ BTF_ID(func, bpf_list_pop_front) BTF_ID(func, bpf_list_pop_back) BTF_ID(func, bpf_cast_to_kern_ctx) BTF_ID(func, bpf_rdonly_cast) +BTF_ID(func, bpf_rcu_read_lock) +BTF_ID(func, bpf_rcu_read_unlock) + +static bool is_kfunc_bpf_rcu_read_lock(struct bpf_kfunc_call_arg_meta *meta) +{ + return meta->func_id == special_kfunc_list[KF_bpf_rcu_read_lock]; +} + +static bool is_kfunc_bpf_rcu_read_unlock(struct bpf_kfunc_call_arg_meta *meta) +{ + return meta->func_id == special_kfunc_list[KF_bpf_rcu_read_unlock]; +} static enum kfunc_ptr_arg_type get_kfunc_ptr_arg_type(struct bpf_verifier_env *env, @@ -8817,6 +8873,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, const struct btf_type *t, *func, *func_proto, *ptr_type; struct bpf_reg_state *regs = cur_regs(env); const char *func_name, *ptr_type_name; + bool sleepable, rcu_lock, rcu_unlock; struct bpf_kfunc_call_arg_meta meta; u32 i, nargs, func_id, ptr_type_id; int err, insn_idx = *insn_idx_p; @@ -8858,11 +8915,45 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, return -EACCES; } - if (is_kfunc_sleepable(&meta) && !env->prog->aux->sleepable) { + sleepable = is_kfunc_sleepable(&meta); + if (sleepable && !env->prog->aux->sleepable) { verbose(env, "program must be sleepable to call sleepable kfunc %s\n", func_name); return -EACCES; } + rcu_lock = is_kfunc_bpf_rcu_read_lock(&meta); + rcu_unlock = is_kfunc_bpf_rcu_read_unlock(&meta); + if ((rcu_lock || rcu_unlock) && !env->rcu_tag_supported) { + verbose(env, "no vmlinux btf rcu tag support for kfunc %s\n", func_name); + return -EACCES; + } + + if (env->cur_state->active_rcu_lock) { + struct bpf_func_state *state; + struct bpf_reg_state *reg; + + if (rcu_lock) { + verbose(env, "nested rcu read lock (kernel function %s)\n", func_name); + return -EINVAL; + } else if (rcu_unlock) { + bpf_for_each_reg_in_vstate(env->cur_state, state, reg, ({ + if (reg->type & MEM_RCU) { + reg->type &= ~(MEM_RCU | PTR_TRUSTED); + reg->type |= PTR_UNTRUSTED; + } + })); + env->cur_state->active_rcu_lock = false; + } else if (sleepable) { + verbose(env, "kernel func %s is sleepable within rcu_read_lock region\n", func_name); + return -EACCES; + } + } else if (rcu_lock) { + env->cur_state->active_rcu_lock = true; + } else if (rcu_unlock) { + verbose(env, "unmatched rcu read unlock (kernel function %s)\n", func_name); + return -EINVAL; + } + /* Check the arguments */ err = check_kfunc_args(env, &meta); if (err < 0) @@ -11754,6 +11845,11 @@ static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn) return -EINVAL; } + if (env->cur_state->active_rcu_lock) { + verbose(env, "BPF_LD_[ABS|IND] cannot be used inside bpf_rcu_read_lock-ed region\n"); + return -EINVAL; + } + if (regs[ctx_reg].type != PTR_TO_CTX) { verbose(env, "at the time of BPF_LD_ABS|IND R6 != pointer to skb\n"); @@ -13019,6 +13115,9 @@ static bool states_equal(struct bpf_verifier_env *env, old->active_lock.id != cur->active_lock.id) return false; + if (old->active_rcu_lock != cur->active_rcu_lock) + return false; + /* for states to be equal callsites have to be the same * and all frame states need to be equivalent */ @@ -13706,6 +13805,11 @@ static int do_check(struct bpf_verifier_env *env) return -EINVAL; } + if (env->cur_state->active_rcu_lock) { + verbose(env, "bpf_rcu_read_unlock is missing\n"); + return -EINVAL; + } + /* We must do check_reference_leak here before * prepare_func_exit to handle the case when * state->curframe > 0, it may be a callback @@ -15494,14 +15598,12 @@ static int do_misc_fixups(struct bpf_verifier_env *env) goto patch_call_imm; } - if (insn->imm == BPF_FUNC_task_storage_get || - insn->imm == BPF_FUNC_sk_storage_get || - insn->imm == BPF_FUNC_inode_storage_get || - insn->imm == BPF_FUNC_cgrp_storage_get) { - if (env->prog->aux->sleepable) - insn_buf[0] = BPF_MOV64_IMM(BPF_REG_5, (__force __s32)GFP_KERNEL); - else + if (is_storage_get_function(insn->imm)) { + if (!env->prog->aux->sleepable || + env->insn_aux_data[i + delta].storage_get_func_atomic) insn_buf[0] = BPF_MOV64_IMM(BPF_REG_5, (__force __s32)GFP_ATOMIC); + else + insn_buf[0] = BPF_MOV64_IMM(BPF_REG_5, (__force __s32)GFP_KERNEL); insn_buf[1] = *insn; cnt = 2; @@ -16580,6 +16682,8 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr) env->bypass_spec_v1 = bpf_bypass_spec_v1(); env->bypass_spec_v4 = bpf_bypass_spec_v4(); env->bpf_capable = bpf_capable(); + env->rcu_tag_supported = btf_vmlinux && + btf_find_by_name_kind(btf_vmlinux, "rcu", BTF_KIND_TYPE_TAG) > 0; if (is_priv) env->test_state_freq = attr->prog_flags & BPF_F_TEST_STATE_FREQ; From 48671232fcb81b76be13c11b0df7089b16baea57 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Wed, 23 Nov 2022 21:32:22 -0800 Subject: [PATCH 097/101] selftests/bpf: Add tests for bpf_rcu_read_lock() Add a few positive/negative tests to test bpf_rcu_read_lock() and its corresponding verifier support. The new test will fail on s390x and aarch64, so an entry is added to each of their respective deny lists. Acked-by: Martin KaFai Lau Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20221124053222.2374650-1-yhs@fb.com Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/DENYLIST.aarch64 | 1 + tools/testing/selftests/bpf/DENYLIST.s390x | 1 + .../selftests/bpf/prog_tests/rcu_read_lock.c | 158 ++++++++++ .../selftests/bpf/progs/rcu_read_lock.c | 290 ++++++++++++++++++ 4 files changed, 450 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/rcu_read_lock.c create mode 100644 tools/testing/selftests/bpf/progs/rcu_read_lock.c diff --git a/tools/testing/selftests/bpf/DENYLIST.aarch64 b/tools/testing/selftests/bpf/DENYLIST.aarch64 index affc5aebbf0f..8e77515d56f6 100644 --- a/tools/testing/selftests/bpf/DENYLIST.aarch64 +++ b/tools/testing/selftests/bpf/DENYLIST.aarch64 @@ -45,6 +45,7 @@ modify_return # modify_return__attach failed module_attach # skel_attach skeleton attach failed: -524 mptcp/base # run_test mptcp unexpected error: -524 (errno 524) netcnt # packets unexpected packets: actual 10001 != expected 10000 +rcu_read_lock # failed to attach: ERROR: strerror_r(-524)=22 recursion # skel_attach unexpected error: -524 (errno 524) ringbuf # skel_attach skeleton attachment failed: -1 setget_sockopt # attach_cgroup unexpected error: -524 diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x index b9a3d80204c6..648a8a1b6b78 100644 --- a/tools/testing/selftests/bpf/DENYLIST.s390x +++ b/tools/testing/selftests/bpf/DENYLIST.s390x @@ -43,6 +43,7 @@ module_attach # skel_attach skeleton attach failed: - mptcp netcnt # failed to load BPF skeleton 'netcnt_prog': -7 (?) probe_user # check_kprobe_res wrong kprobe res from probe read (?) +rcu_read_lock # failed to find kernel BTF type ID of '__x64_sys_getpgid': -3 (?) recursion # skel_attach unexpected error: -524 (trampoline) ringbuf # skel_load skeleton load failed (?) select_reuseport # intermittently fails on new s390x setup diff --git a/tools/testing/selftests/bpf/prog_tests/rcu_read_lock.c b/tools/testing/selftests/bpf/prog_tests/rcu_read_lock.c new file mode 100644 index 000000000000..447d8560ecb6 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/rcu_read_lock.c @@ -0,0 +1,158 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates.*/ + +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include "rcu_read_lock.skel.h" +#include "cgroup_helpers.h" + +static unsigned long long cgroup_id; + +static void test_success(void) +{ + struct rcu_read_lock *skel; + int err; + + skel = rcu_read_lock__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + skel->bss->target_pid = syscall(SYS_gettid); + + bpf_program__set_autoload(skel->progs.get_cgroup_id, true); + bpf_program__set_autoload(skel->progs.task_succ, true); + bpf_program__set_autoload(skel->progs.no_lock, true); + bpf_program__set_autoload(skel->progs.two_regions, true); + bpf_program__set_autoload(skel->progs.non_sleepable_1, true); + bpf_program__set_autoload(skel->progs.non_sleepable_2, true); + err = rcu_read_lock__load(skel); + if (!ASSERT_OK(err, "skel_load")) + goto out; + + err = rcu_read_lock__attach(skel); + if (!ASSERT_OK(err, "skel_attach")) + goto out; + + syscall(SYS_getpgid); + + ASSERT_EQ(skel->bss->task_storage_val, 2, "task_storage_val"); + ASSERT_EQ(skel->bss->cgroup_id, cgroup_id, "cgroup_id"); +out: + rcu_read_lock__destroy(skel); +} + +static void test_rcuptr_acquire(void) +{ + struct rcu_read_lock *skel; + int err; + + skel = rcu_read_lock__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + skel->bss->target_pid = syscall(SYS_gettid); + + bpf_program__set_autoload(skel->progs.task_acquire, true); + err = rcu_read_lock__load(skel); + if (!ASSERT_OK(err, "skel_load")) + goto out; + + err = rcu_read_lock__attach(skel); + ASSERT_OK(err, "skel_attach"); +out: + rcu_read_lock__destroy(skel); +} + +static const char * const inproper_region_tests[] = { + "miss_lock", + "miss_unlock", + "non_sleepable_rcu_mismatch", + "inproper_sleepable_helper", + "inproper_sleepable_kfunc", + "nested_rcu_region", +}; + +static void test_inproper_region(void) +{ + struct rcu_read_lock *skel; + struct bpf_program *prog; + int i, err; + + for (i = 0; i < ARRAY_SIZE(inproper_region_tests); i++) { + skel = rcu_read_lock__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + prog = bpf_object__find_program_by_name(skel->obj, inproper_region_tests[i]); + if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name")) + goto out; + bpf_program__set_autoload(prog, true); + err = rcu_read_lock__load(skel); + ASSERT_ERR(err, "skel_load"); +out: + rcu_read_lock__destroy(skel); + } +} + +static const char * const rcuptr_misuse_tests[] = { + "task_untrusted_non_rcuptr", + "task_untrusted_rcuptr", + "cross_rcu_region", +}; + +static void test_rcuptr_misuse(void) +{ + struct rcu_read_lock *skel; + struct bpf_program *prog; + int i, err; + + for (i = 0; i < ARRAY_SIZE(rcuptr_misuse_tests); i++) { + skel = rcu_read_lock__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + prog = bpf_object__find_program_by_name(skel->obj, rcuptr_misuse_tests[i]); + if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name")) + goto out; + bpf_program__set_autoload(prog, true); + err = rcu_read_lock__load(skel); + ASSERT_ERR(err, "skel_load"); +out: + rcu_read_lock__destroy(skel); + } +} + +void test_rcu_read_lock(void) +{ + struct btf *vmlinux_btf; + int cgroup_fd; + + vmlinux_btf = btf__load_vmlinux_btf(); + if (!ASSERT_OK_PTR(vmlinux_btf, "could not load vmlinux BTF")) + return; + if (btf__find_by_name_kind(vmlinux_btf, "rcu", BTF_KIND_TYPE_TAG) < 0) { + test__skip(); + goto out; + } + + cgroup_fd = test__join_cgroup("/rcu_read_lock"); + if (!ASSERT_GE(cgroup_fd, 0, "join_cgroup /rcu_read_lock")) + goto out; + + cgroup_id = get_cgroup_id("/rcu_read_lock"); + if (test__start_subtest("success")) + test_success(); + if (test__start_subtest("rcuptr_acquire")) + test_rcuptr_acquire(); + if (test__start_subtest("negative_tests_inproper_region")) + test_inproper_region(); + if (test__start_subtest("negative_tests_rcuptr_misuse")) + test_rcuptr_misuse(); + close(cgroup_fd); +out: + btf__free(vmlinux_btf); +} diff --git a/tools/testing/selftests/bpf/progs/rcu_read_lock.c b/tools/testing/selftests/bpf/progs/rcu_read_lock.c new file mode 100644 index 000000000000..94a970076b98 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/rcu_read_lock.c @@ -0,0 +1,290 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ + +#include "vmlinux.h" +#include +#include +#include "bpf_tracing_net.h" +#include "bpf_misc.h" + +char _license[] SEC("license") = "GPL"; + +struct { + __uint(type, BPF_MAP_TYPE_TASK_STORAGE); + __uint(map_flags, BPF_F_NO_PREALLOC); + __type(key, int); + __type(value, long); +} map_a SEC(".maps"); + +__u32 user_data, key_serial, target_pid; +__u64 flags, task_storage_val, cgroup_id; + +struct bpf_key *bpf_lookup_user_key(__u32 serial, __u64 flags) __ksym; +void bpf_key_put(struct bpf_key *key) __ksym; +void bpf_rcu_read_lock(void) __ksym; +void bpf_rcu_read_unlock(void) __ksym; +struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym; +void bpf_task_release(struct task_struct *p) __ksym; + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int get_cgroup_id(void *ctx) +{ + struct task_struct *task; + + task = bpf_get_current_task_btf(); + if (task->pid != target_pid) + return 0; + + /* simulate bpf_get_current_cgroup_id() helper */ + bpf_rcu_read_lock(); + cgroup_id = task->cgroups->dfl_cgrp->kn->id; + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int task_succ(void *ctx) +{ + struct task_struct *task, *real_parent; + long init_val = 2; + long *ptr; + + task = bpf_get_current_task_btf(); + if (task->pid != target_pid) + return 0; + + bpf_rcu_read_lock(); + /* region including helper using rcu ptr real_parent */ + real_parent = task->real_parent; + ptr = bpf_task_storage_get(&map_a, real_parent, &init_val, + BPF_LOCAL_STORAGE_GET_F_CREATE); + if (!ptr) + goto out; + ptr = bpf_task_storage_get(&map_a, real_parent, 0, 0); + if (!ptr) + goto out; + task_storage_val = *ptr; +out: + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") +int no_lock(void *ctx) +{ + struct task_struct *task, *real_parent; + + /* no bpf_rcu_read_lock(), old code still works */ + task = bpf_get_current_task_btf(); + real_parent = task->real_parent; + (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") +int two_regions(void *ctx) +{ + struct task_struct *task, *real_parent; + + /* two regions */ + task = bpf_get_current_task_btf(); + bpf_rcu_read_lock(); + bpf_rcu_read_unlock(); + bpf_rcu_read_lock(); + real_parent = task->real_parent; + (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry/" SYS_PREFIX "sys_getpgid") +int non_sleepable_1(void *ctx) +{ + struct task_struct *task, *real_parent; + + task = bpf_get_current_task_btf(); + bpf_rcu_read_lock(); + real_parent = task->real_parent; + (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry/" SYS_PREFIX "sys_getpgid") +int non_sleepable_2(void *ctx) +{ + struct task_struct *task, *real_parent; + + bpf_rcu_read_lock(); + task = bpf_get_current_task_btf(); + bpf_rcu_read_unlock(); + + bpf_rcu_read_lock(); + real_parent = task->real_parent; + (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") +int task_acquire(void *ctx) +{ + struct task_struct *task, *real_parent; + + task = bpf_get_current_task_btf(); + bpf_rcu_read_lock(); + real_parent = task->real_parent; + /* acquire a reference which can be used outside rcu read lock region */ + real_parent = bpf_task_acquire(real_parent); + bpf_rcu_read_unlock(); + (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); + bpf_task_release(real_parent); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int miss_lock(void *ctx) +{ + struct task_struct *task; + struct css_set *cgroups; + struct cgroup *dfl_cgrp; + + /* missing bpf_rcu_read_lock() */ + task = bpf_get_current_task_btf(); + bpf_rcu_read_lock(); + (void)bpf_task_storage_get(&map_a, task, 0, 0); + bpf_rcu_read_unlock(); + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int miss_unlock(void *ctx) +{ + struct task_struct *task; + struct css_set *cgroups; + struct cgroup *dfl_cgrp; + + /* missing bpf_rcu_read_unlock() */ + task = bpf_get_current_task_btf(); + bpf_rcu_read_lock(); + (void)bpf_task_storage_get(&map_a, task, 0, 0); + return 0; +} + +SEC("?fentry/" SYS_PREFIX "sys_getpgid") +int non_sleepable_rcu_mismatch(void *ctx) +{ + struct task_struct *task, *real_parent; + + task = bpf_get_current_task_btf(); + /* non-sleepable: missing bpf_rcu_read_unlock() in one path */ + bpf_rcu_read_lock(); + real_parent = task->real_parent; + (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); + if (real_parent) + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int inproper_sleepable_helper(void *ctx) +{ + struct task_struct *task, *real_parent; + struct pt_regs *regs; + __u32 value = 0; + void *ptr; + + task = bpf_get_current_task_btf(); + /* sleepable helper in rcu read lock region */ + bpf_rcu_read_lock(); + real_parent = task->real_parent; + regs = (struct pt_regs *)bpf_task_pt_regs(real_parent); + if (!regs) { + bpf_rcu_read_unlock(); + return 0; + } + + ptr = (void *)PT_REGS_IP(regs); + (void)bpf_copy_from_user_task(&value, sizeof(uint32_t), ptr, task, 0); + user_data = value; + (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?lsm.s/bpf") +int BPF_PROG(inproper_sleepable_kfunc, int cmd, union bpf_attr *attr, unsigned int size) +{ + struct bpf_key *bkey; + + /* sleepable kfunc in rcu read lock region */ + bpf_rcu_read_lock(); + bkey = bpf_lookup_user_key(key_serial, flags); + bpf_rcu_read_unlock(); + if (!bkey) + return -1; + bpf_key_put(bkey); + + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") +int nested_rcu_region(void *ctx) +{ + struct task_struct *task, *real_parent; + + /* nested rcu read lock regions */ + task = bpf_get_current_task_btf(); + bpf_rcu_read_lock(); + bpf_rcu_read_lock(); + real_parent = task->real_parent; + (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); + bpf_rcu_read_unlock(); + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int task_untrusted_non_rcuptr(void *ctx) +{ + struct task_struct *task, *last_wakee; + + task = bpf_get_current_task_btf(); + bpf_rcu_read_lock(); + /* the pointer last_wakee marked as untrusted */ + last_wakee = task->real_parent->last_wakee; + (void)bpf_task_storage_get(&map_a, last_wakee, 0, 0); + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int task_untrusted_rcuptr(void *ctx) +{ + struct task_struct *task, *real_parent; + + task = bpf_get_current_task_btf(); + bpf_rcu_read_lock(); + real_parent = task->real_parent; + bpf_rcu_read_unlock(); + /* helper use of rcu ptr outside the rcu read lock region */ + (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") +int cross_rcu_region(void *ctx) +{ + struct task_struct *task, *real_parent; + + /* rcu ptr define/use in different regions */ + task = bpf_get_current_task_btf(); + bpf_rcu_read_lock(); + real_parent = task->real_parent; + bpf_rcu_read_unlock(); + bpf_rcu_read_lock(); + (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); + bpf_rcu_read_unlock(); + return 0; +} From c6b0337f01205decb31ed5e90e5aa760ac2d5b41 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Thu, 24 Nov 2022 13:53:14 -0800 Subject: [PATCH 098/101] bpf: Don't mark arguments to fentry/fexit programs as trusted. The PTR_TRUSTED flag should only be applied to pointers where the verifier can guarantee that such pointers are valid. The fentry/fexit/fmod_ret programs are not in this category. Only arguments of SEC("tp_btf") and SEC("iter") programs are trusted (which have BPF_TRACE_RAW_TP and BPF_TRACE_ITER attach_type correspondingly) This bug was masked because convert_ctx_accesses() was converting trusted loads into BPF_PROBE_MEM loads. Fix it as well. The loads from trusted pointers don't need exception handling. Fixes: 3f00c5239344 ("bpf: Allow trusted pointers to be passed to KF_TRUSTED_ARGS kfuncs") Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20221124215314.55890-1-alexei.starovoitov@gmail.com --- kernel/bpf/btf.c | 16 +++++++++++++--- kernel/bpf/verifier.c | 3 --- 2 files changed, 13 insertions(+), 6 deletions(-) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index bd3369100239..d11cbf8cece7 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -5821,9 +5821,19 @@ static u32 get_ctx_arg_idx(struct btf *btf, const struct btf_type *func_proto, return nr_args + 1; } -static bool prog_type_args_trusted(enum bpf_prog_type prog_type) +static bool prog_args_trusted(const struct bpf_prog *prog) { - return prog_type == BPF_PROG_TYPE_TRACING || prog_type == BPF_PROG_TYPE_STRUCT_OPS; + enum bpf_attach_type atype = prog->expected_attach_type; + + switch (prog->type) { + case BPF_PROG_TYPE_TRACING: + return atype == BPF_TRACE_RAW_TP || atype == BPF_TRACE_ITER; + case BPF_PROG_TYPE_LSM: + case BPF_PROG_TYPE_STRUCT_OPS: + return true; + default: + return false; + } } bool btf_ctx_access(int off, int size, enum bpf_access_type type, @@ -5969,7 +5979,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, } info->reg_type = PTR_TO_BTF_ID; - if (prog_type_args_trusted(prog->type)) + if (prog_args_trusted(prog)) info->reg_type |= PTR_TRUSTED; if (tgt_prog) { diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index f4500479f1c2..6599d25dae38 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -14905,7 +14905,6 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) break; case PTR_TO_BTF_ID: case PTR_TO_BTF_ID | PTR_UNTRUSTED: - case PTR_TO_BTF_ID | PTR_TRUSTED: /* PTR_TO_BTF_ID | MEM_ALLOC always has a valid lifetime, unlike * PTR_TO_BTF_ID, and an active ref_obj_id, but the same cannot * be said once it is marked PTR_UNTRUSTED, hence we must handle @@ -14913,8 +14912,6 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) * for this case. */ case PTR_TO_BTF_ID | MEM_ALLOC | PTR_UNTRUSTED: - case PTR_TO_BTF_ID | PTR_UNTRUSTED | PTR_TRUSTED: - case PTR_TO_BTF_ID | PTR_UNTRUSTED | MEM_ALLOC | PTR_TRUSTED: if (type == BPF_READ) { insn->code = BPF_LDX | BPF_PROBE_MEM | BPF_SIZE((insn)->code); From b74344cbede22fdfc1366348b3d576eac0131380 Mon Sep 17 00:00:00 2001 From: Rong Tao Date: Tue, 22 Nov 2022 08:50:42 +0800 Subject: [PATCH 099/101] docs/bpf: Update btf selftests program and add link Commit c64779e24e88("selftests/bpf: Merge most of test_btf into test_progs") renamed the BTF selftest from 'test_btf.c' to 'prog_tests/btf.c'. Signed-off-by: Rong Tao Signed-off-by: Daniel Borkmann Acked-by: David Vernet Link: https://lore.kernel.org/bpf/tencent_1FA6904156E8E599CAE4ABDBE80F22830106@qq.com --- Documentation/bpf/btf.rst | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/Documentation/bpf/btf.rst b/Documentation/bpf/btf.rst index cf8722f96090..7cd7c5415a99 100644 --- a/Documentation/bpf/btf.rst +++ b/Documentation/bpf/btf.rst @@ -1062,4 +1062,9 @@ format.:: 7. Testing ========== -Kernel bpf selftest `test_btf.c` provides extensive set of BTF-related tests. +The kernel BPF selftest `tools/testing/selftests/bpf/prog_tests/btf.c`_ +provides an extensive set of BTF-related tests. + +.. Links +.. _tools/testing/selftests/bpf/prog_tests/btf.c: + https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/tools/testing/selftests/bpf/prog_tests/btf.c From 19a2bdbaaddc71405494bd35fa034d9cf582b05e Mon Sep 17 00:00:00 2001 From: Rong Tao Date: Tue, 22 Nov 2022 10:32:56 +0800 Subject: [PATCH 100/101] samples/bpf: Fix wrong allocation size in xdp_router_ipv4_user prefix_key->data allocates three bytes using alloca(), but four bytes are actually accessed in the program. Signed-off-by: Rong Tao Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/tencent_F9E2E81922B0C181D05B96DAE5AB0ACE6B06@qq.com --- samples/bpf/xdp_router_ipv4_user.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/samples/bpf/xdp_router_ipv4_user.c b/samples/bpf/xdp_router_ipv4_user.c index 683913bbf279..9d41db09c480 100644 --- a/samples/bpf/xdp_router_ipv4_user.c +++ b/samples/bpf/xdp_router_ipv4_user.c @@ -162,7 +162,7 @@ static void read_route(struct nlmsghdr *nh, int nll) __be32 gw; } *prefix_value; - prefix_key = alloca(sizeof(*prefix_key) + 3); + prefix_key = alloca(sizeof(*prefix_key) + 4); prefix_value = alloca(sizeof(*prefix_value)); prefix_key->prefixlen = 32; From 2b3e8f6f5b939ceeb2e097339bf78ebaaf11dfe9 Mon Sep 17 00:00:00 2001 From: Maryam Tahhan Date: Wed, 23 Nov 2022 09:00:43 +0000 Subject: [PATCH 101/101] docs/bpf: Add BPF_MAP_TYPE_XSKMAP documentation Add documentation for BPF_MAP_TYPE_XSKMAP including kernel version introduced, usage and examples. Signed-off-by: Maryam Tahhan Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20221123090043.83945-1-mtahhan@redhat.com --- Documentation/bpf/map_xskmap.rst | 192 +++++++++++++++++++++++++++++++ 1 file changed, 192 insertions(+) create mode 100644 Documentation/bpf/map_xskmap.rst diff --git a/Documentation/bpf/map_xskmap.rst b/Documentation/bpf/map_xskmap.rst new file mode 100644 index 000000000000..7093b8208451 --- /dev/null +++ b/Documentation/bpf/map_xskmap.rst @@ -0,0 +1,192 @@ +.. SPDX-License-Identifier: GPL-2.0-only +.. Copyright (C) 2022 Red Hat, Inc. + +=================== +BPF_MAP_TYPE_XSKMAP +=================== + +.. note:: + - ``BPF_MAP_TYPE_XSKMAP`` was introduced in kernel version 4.18 + +The ``BPF_MAP_TYPE_XSKMAP`` is used as a backend map for XDP BPF helper +call ``bpf_redirect_map()`` and ``XDP_REDIRECT`` action, like 'devmap' and 'cpumap'. +This map type redirects raw XDP frames to `AF_XDP`_ sockets (XSKs), a new type of +address family in the kernel that allows redirection of frames from a driver to +user space without having to traverse the full network stack. An AF_XDP socket +binds to a single netdev queue. A mapping of XSKs to queues is shown below: + +.. code-block:: none + + +---------------------------------------------------+ + | xsk A | xsk B | xsk C |<---+ User space + =========================================================|========== + | Queue 0 | Queue 1 | Queue 2 | | Kernel + +---------------------------------------------------+ | + | Netdev eth0 | | + +---------------------------------------------------+ | + | +=============+ | | + | | key | xsk | | | + | +---------+ +=============+ | | + | | | | 0 | xsk A | | | + | | | +-------------+ | | + | | | | 1 | xsk B | | | + | | BPF |-- redirect -->+-------------+-------------+ + | | prog | | 2 | xsk C | | + | | | +-------------+ | + | | | | + | | | | + | +---------+ | + | | + +---------------------------------------------------+ + +.. note:: + An AF_XDP socket that is bound to a certain will *only* + accept XDP frames from that . If an XDP program tries to redirect + from a other than what the socket is bound to, the frame will + not be received on the socket. + +Typically an XSKMAP is created per netdev. This map contains an array of XSK File +Descriptors (FDs). The number of array elements is typically set or adjusted using +the ``max_entries`` map parameter. For AF_XDP ``max_entries`` is equal to the number +of queues supported by the netdev. + +.. note:: + Both the map key and map value size must be 4 bytes. + +Usage +===== + +Kernel BPF +---------- +bpf_redirect_map() +^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + long bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags) + +Redirect the packet to the endpoint referenced by ``map`` at index ``key``. +For ``BPF_MAP_TYPE_XSKMAP`` this map contains references to XSK FDs +for sockets attached to a netdev's queues. + +.. note:: + If the map is empty at an index, the packet is dropped. This means that it is + necessary to have an XDP program loaded with at least one XSK in the + XSKMAP to be able to get any traffic to user space through the socket. + +bpf_map_lookup_elem() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + void *bpf_map_lookup_elem(struct bpf_map *map, const void *key) + +XSK entry references of type ``struct xdp_sock *`` can be retrieved using the +``bpf_map_lookup_elem()`` helper. + +User space +---------- +.. note:: + XSK entries can only be updated/deleted from user space and not from + a BPF program. Trying to call these functions from a kernel BPF program will + result in the program failing to load and a verifier warning. + +bpf_map_update_elem() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + int bpf_map_update_elem(int fd, const void *key, const void *value, __u64 flags) + +XSK entries can be added or updated using the ``bpf_map_update_elem()`` +helper. The ``key`` parameter is equal to the queue_id of the queue the XSK +is attaching to. And the ``value`` parameter is the FD value of that socket. + +Under the hood, the XSKMAP update function uses the XSK FD value to retrieve the +associated ``struct xdp_sock`` instance. + +The flags argument can be one of the following: + +- BPF_ANY: Create a new element or update an existing element. +- BPF_NOEXIST: Create a new element only if it did not exist. +- BPF_EXIST: Update an existing element. + +bpf_map_lookup_elem() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + int bpf_map_lookup_elem(int fd, const void *key, void *value) + +Returns ``struct xdp_sock *`` or negative error in case of failure. + +bpf_map_delete_elem() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + int bpf_map_delete_elem(int fd, const void *key) + +XSK entries can be deleted using the ``bpf_map_delete_elem()`` +helper. This helper will return 0 on success, or negative error in case of +failure. + +.. note:: + When `libxdp`_ deletes an XSK it also removes the associated socket + entry from the XSKMAP. + +Examples +======== +Kernel +------ + +The following code snippet shows how to declare a ``BPF_MAP_TYPE_XSKMAP`` called +``xsks_map`` and how to redirect packets to an XSK. + +.. code-block:: c + + struct { + __uint(type, BPF_MAP_TYPE_XSKMAP); + __type(key, __u32); + __type(value, __u32); + __uint(max_entries, 64); + } xsks_map SEC(".maps"); + + + SEC("xdp") + int xsk_redir_prog(struct xdp_md *ctx) + { + __u32 index = ctx->rx_queue_index; + + if (bpf_map_lookup_elem(&xsks_map, &index)) + return bpf_redirect_map(&xsks_map, index, 0); + return XDP_PASS; + } + +User space +---------- + +The following code snippet shows how to update an XSKMAP with an XSK entry. + +.. code-block:: c + + int update_xsks_map(struct bpf_map *xsks_map, int queue_id, int xsk_fd) + { + int ret; + + ret = bpf_map_update_elem(bpf_map__fd(xsks_map), &queue_id, &xsk_fd, 0); + if (ret < 0) + fprintf(stderr, "Failed to update xsks_map: %s\n", strerror(errno)); + + return ret; + } + +For an example on how create AF_XDP sockets, please see the AF_XDP-example and +AF_XDP-forwarding programs in the `bpf-examples`_ directory in the `libxdp`_ repository. +For a detailed explaination of the AF_XDP interface please see: + +- `libxdp-readme`_. +- `AF_XDP`_ kernel documentation. + +.. note:: + The most comprehensive resource for using XSKMAPs and AF_XDP is `libxdp`_. + +.. _libxdp: https://github.com/xdp-project/xdp-tools/tree/master/lib/libxdp +.. _AF_XDP: https://www.kernel.org/doc/html/latest/networking/af_xdp.html +.. _bpf-examples: https://github.com/xdp-project/bpf-examples +.. _libxdp-readme: https://github.com/xdp-project/xdp-tools/tree/master/lib/libxdp#using-af_xdp-sockets