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bpf: Rename MEM_ALLOC to MEM_RINGBUF

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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 <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221114191547.1694267-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Kumar Kartikeya Dwivedi 2022-11-15 00:45:27 +05:30 committed by Alexei Starovoitov
parent 2de2669b4e
commit 894f2a8b16
6 changed files with 17 additions and 20 deletions
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11
include/linux/bpf.h
View File

@ -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,

6
kernel/bpf/ringbuf.c
View File

@ -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,
};

14
kernel/bpf/verifier.c
View File

@ -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

2
tools/testing/selftests/bpf/prog_tests/dynptr.c
View File

@ -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"},

2
tools/testing/selftests/bpf/verifier/ringbuf.c
View File

@ -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",

2
tools/testing/selftests/bpf/verifier/spill_fill.c
View File

@ -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",