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Merge branch 'btf-check-name'

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Yonghong Song says:

====================
This patch set added name checking for PTR, ARRAY, VOLATILE, TYPEDEF,
CONST, RESTRICT, STRUCT, UNION, ENUM and FWD types. Such a strict
name checking makes BTF more sound in the kernel and future
BTF-to-header-file converesion ([1]) less fragile.

Patch #1 implemented btf_name_valid_identifier() for name checking
which will be used in Patch #2.
Patch #2 checked name validity for the above mentioned types.
Patch #3 fixed two existing test_btf unit tests exposed by the strict
name checking.
Patch #4 added additional test cases.

This patch set is against bpf tree.

Patch #1 has been implemented in bpf-next commit
Commit 2667a2626f4d ("bpf: btf: Add BTF_KIND_FUNC
and BTF_KIND_FUNC_PROTO"), so there is no need to apply this
patch to bpf-next. In case this patch is applied to bpf-next,
there will be a minor conflict like
  diff --cc kernel/bpf/btf.c
  index a09b2f94ab25,93c233ab2db6..000000000000
  --- a/kernel/bpf/btf.c
  +++ b/kernel/bpf/btf.c
  @@@ -474,7 -451,7 +474,11 @@@ static bool btf_name_valid_identifier(c
          return !*src;
    }

  ++<<<<<<< HEAD
   +const char *btf_name_by_offset(const struct btf *btf, u32 offset)
  ++=======
  + static const char *btf_name_by_offset(const struct btf *btf, u32 offset)
  ++>>>>>>> fa9566b0847d... bpf: btf: implement btf_name_valid_identifier()
    {
          if (!offset)
                  return "(anon)";
Just resolve the conflict by taking the "const char ..." line.

Patches #2, #3 and #4 can be applied to bpf-next without conflict.

[1]: http://vger.kernel.org/lpc-bpf2018.html#session-2
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Alexei Starovoitov 2018-11-28 16:03:05 -08:00
commit c2209c6d18
2 changed files with 450 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

82
kernel/bpf/btf.c
View File

@ -5,6 +5,7 @@
#include <uapi/linux/types.h>
#include <linux/seq_file.h>
#include <linux/compiler.h>
#include <linux/ctype.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/anon_inodes.h>
@ -426,6 +427,30 @@ static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
offset < btf->hdr.str_len;
}
/* Only C-style identifier is permitted. This can be relaxed if
* necessary.
*/
static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
{
/* offset must be valid */
const char *src = &btf->strings[offset];
const char *src_limit;
if (!isalpha(*src) && *src != '_')
return false;
/* set a limit on identifier length */
src_limit = src + KSYM_NAME_LEN;
src++;
while (*src && src < src_limit) {
if (!isalnum(*src) && *src != '_')
return false;
src++;
}
return !*src;
}
static const char *btf_name_by_offset(const struct btf *btf, u32 offset)
{
if (!offset)
@ -1143,6 +1168,22 @@ static int btf_ref_type_check_meta(struct btf_verifier_env *env,
return -EINVAL;
}
/* typedef type must have a valid name, and other ref types,
* volatile, const, restrict, should have a null name.
*/
if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
if (!t->name_off ||
!btf_name_valid_identifier(env->btf, t->name_off)) {
btf_verifier_log_type(env, t, "Invalid name");
return -EINVAL;
}
} else {
if (t->name_off) {
btf_verifier_log_type(env, t, "Invalid name");
return -EINVAL;
}
}
btf_verifier_log_type(env, t, NULL);
return 0;
@ -1300,6 +1341,13 @@ static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
return -EINVAL;
}
/* fwd type must have a valid name */
if (!t->name_off ||
!btf_name_valid_identifier(env->btf, t->name_off)) {
btf_verifier_log_type(env, t, "Invalid name");
return -EINVAL;
}
btf_verifier_log_type(env, t, NULL);
return 0;
@ -1356,6 +1404,12 @@ static s32 btf_array_check_meta(struct btf_verifier_env *env,
return -EINVAL;
}
/* array type should not have a name */
if (t->name_off) {
btf_verifier_log_type(env, t, "Invalid name");
return -EINVAL;
}
if (btf_type_vlen(t)) {
btf_verifier_log_type(env, t, "vlen != 0");
return -EINVAL;
@ -1532,6 +1586,13 @@ static s32 btf_struct_check_meta(struct btf_verifier_env *env,
return -EINVAL;
}
/* struct type either no name or a valid one */
if (t->name_off &&
!btf_name_valid_identifier(env->btf, t->name_off)) {
btf_verifier_log_type(env, t, "Invalid name");
return -EINVAL;
}
btf_verifier_log_type(env, t, NULL);
last_offset = 0;
@ -1543,6 +1604,12 @@ static s32 btf_struct_check_meta(struct btf_verifier_env *env,
return -EINVAL;
}
/* struct member either no name or a valid one */
if (member->name_off &&
!btf_name_valid_identifier(btf, member->name_off)) {
btf_verifier_log_member(env, t, member, "Invalid name");
return -EINVAL;
}
/* A member cannot be in type void */
if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
btf_verifier_log_member(env, t, member,
@ -1730,6 +1797,13 @@ static s32 btf_enum_check_meta(struct btf_verifier_env *env,
return -EINVAL;
}
/* enum type either no name or a valid one */
if (t->name_off &&
!btf_name_valid_identifier(env->btf, t->name_off)) {
btf_verifier_log_type(env, t, "Invalid name");
return -EINVAL;
}
btf_verifier_log_type(env, t, NULL);
for (i = 0; i < nr_enums; i++) {
@ -1739,6 +1813,14 @@ static s32 btf_enum_check_meta(struct btf_verifier_env *env,
return -EINVAL;
}
/* enum member must have a valid name */
if (!enums[i].name_off ||
!btf_name_valid_identifier(btf, enums[i].name_off)) {
btf_verifier_log_type(env, t, "Invalid name");
return -EINVAL;
}
btf_verifier_log(env, "\t%s val=%d\n",
btf_name_by_offset(btf, enums[i].name_off),
enums[i].val);

375
tools/testing/selftests/bpf/test_btf.c
View File

@ -432,11 +432,11 @@ static struct btf_raw_test raw_tests[] = {
/* const void* */ /* [3] */
BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 2),
/* typedef const void * const_void_ptr */
BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 3),
/* struct A { */ /* [4] */
BTF_TYPEDEF_ENC(NAME_TBD, 3), /* [4] */
/* struct A { */ /* [5] */
BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), sizeof(void *)),
/* const_void_ptr m; */
BTF_MEMBER_ENC(NAME_TBD, 3, 0),
BTF_MEMBER_ENC(NAME_TBD, 4, 0),
/* } */
BTF_END_RAW,
},
@ -494,10 +494,10 @@ static struct btf_raw_test raw_tests[] = {
BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_CONST, 0, 0), 0),
/* const void* */ /* [3] */
BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 2),
/* typedef const void * const_void_ptr */ /* [4] */
BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 3),
/* const_void_ptr[4] */ /* [5] */
BTF_TYPE_ARRAY_ENC(3, 1, 4),
/* typedef const void * const_void_ptr */
BTF_TYPEDEF_ENC(NAME_TBD, 3), /* [4] */
/* const_void_ptr[4] */
BTF_TYPE_ARRAY_ENC(4, 1, 4), /* [5] */
BTF_END_RAW,
},
.str_sec = "\0const_void_ptr",
@ -1292,6 +1292,367 @@ static struct btf_raw_test raw_tests[] = {
.err_str = "type != 0",
},
{
.descr = "typedef (invalid name, name_off = 0)",
.raw_types = {
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
BTF_TYPEDEF_ENC(0, 1), /* [2] */
BTF_END_RAW,
},
.str_sec = "\0__int",
.str_sec_size = sizeof("\0__int"),
.map_type = BPF_MAP_TYPE_ARRAY,
.map_name = "typedef_check_btf",
.key_size = sizeof(int),
.value_size = sizeof(int),
.key_type_id = 1,
.value_type_id = 1,
.max_entries = 4,
.btf_load_err = true,
.err_str = "Invalid name",
},
{
.descr = "typedef (invalid name, invalid identifier)",
.raw_types = {
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
BTF_TYPEDEF_ENC(NAME_TBD, 1), /* [2] */
BTF_END_RAW,
},
.str_sec = "\0__!int",
.str_sec_size = sizeof("\0__!int"),
.map_type = BPF_MAP_TYPE_ARRAY,
.map_name = "typedef_check_btf",
.key_size = sizeof(int),
.value_size = sizeof(int),
.key_type_id = 1,
.value_type_id = 1,
.max_entries = 4,
.btf_load_err = true,
.err_str = "Invalid name",
},
{
.descr = "ptr type (invalid name, name_off <> 0)",
.raw_types = {
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
BTF_TYPE_ENC(NAME_TBD,
BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 1), /* [2] */
BTF_END_RAW,
},
.str_sec = "\0__int",
.str_sec_size = sizeof("\0__int"),
.map_type = BPF_MAP_TYPE_ARRAY,
.map_name = "ptr_type_check_btf",
.key_size = sizeof(int),
.value_size = sizeof(int),
.key_type_id = 1,
.value_type_id = 1,
.max_entries = 4,
.btf_load_err = true,
.err_str = "Invalid name",
},
{
.descr = "volatile type (invalid name, name_off <> 0)",
.raw_types = {
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
BTF_TYPE_ENC(NAME_TBD,
BTF_INFO_ENC(BTF_KIND_VOLATILE, 0, 0), 1), /* [2] */
BTF_END_RAW,
},
.str_sec = "\0__int",
.str_sec_size = sizeof("\0__int"),
.map_type = BPF_MAP_TYPE_ARRAY,
.map_name = "volatile_type_check_btf",
.key_size = sizeof(int),
.value_size = sizeof(int),
.key_type_id = 1,
.value_type_id = 1,
.max_entries = 4,
.btf_load_err = true,
.err_str = "Invalid name",
},
{
.descr = "const type (invalid name, name_off <> 0)",
.raw_types = {
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
BTF_TYPE_ENC(NAME_TBD,
BTF_INFO_ENC(BTF_KIND_CONST, 0, 0), 1), /* [2] */
BTF_END_RAW,
},
.str_sec = "\0__int",
.str_sec_size = sizeof("\0__int"),
.map_type = BPF_MAP_TYPE_ARRAY,
.map_name = "const_type_check_btf",
.key_size = sizeof(int),
.value_size = sizeof(int),
.key_type_id = 1,
.value_type_id = 1,
.max_entries = 4,
.btf_load_err = true,
.err_str = "Invalid name",
},
{
.descr = "restrict type (invalid name, name_off <> 0)",
.raw_types = {
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 1), /* [2] */
BTF_TYPE_ENC(NAME_TBD,
BTF_INFO_ENC(BTF_KIND_RESTRICT, 0, 0), 2), /* [3] */
BTF_END_RAW,
},
.str_sec = "\0__int",
.str_sec_size = sizeof("\0__int"),
.map_type = BPF_MAP_TYPE_ARRAY,
.map_name = "restrict_type_check_btf",
.key_size = sizeof(int),
.value_size = sizeof(int),
.key_type_id = 1,
.value_type_id = 1,
.max_entries = 4,
.btf_load_err = true,
.err_str = "Invalid name",
},
{
.descr = "fwd type (invalid name, name_off = 0)",
.raw_types = {
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FWD, 0, 0), 0), /* [2] */
BTF_END_RAW,
},
.str_sec = "\0__skb",
.str_sec_size = sizeof("\0__skb"),
.map_type = BPF_MAP_TYPE_ARRAY,
.map_name = "fwd_type_check_btf",
.key_size = sizeof(int),
.value_size = sizeof(int),
.key_type_id = 1,
.value_type_id = 1,
.max_entries = 4,
.btf_load_err = true,
.err_str = "Invalid name",
},
{
.descr = "fwd type (invalid name, invalid identifier)",
.raw_types = {
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
BTF_TYPE_ENC(NAME_TBD,
BTF_INFO_ENC(BTF_KIND_FWD, 0, 0), 0), /* [2] */
BTF_END_RAW,
},
.str_sec = "\0__!skb",
.str_sec_size = sizeof("\0__!skb"),
.map_type = BPF_MAP_TYPE_ARRAY,
.map_name = "fwd_type_check_btf",
.key_size = sizeof(int),
.value_size = sizeof(int),
.key_type_id = 1,
.value_type_id = 1,
.max_entries = 4,
.btf_load_err = true,
.err_str = "Invalid name",
},
{
.descr = "array type (invalid name, name_off <> 0)",
.raw_types = {
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
BTF_TYPE_ENC(NAME_TBD,
BTF_INFO_ENC(BTF_KIND_ARRAY, 0, 0), 0), /* [2] */
BTF_ARRAY_ENC(1, 1, 4),
BTF_END_RAW,
},
.str_sec = "\0__skb",
.str_sec_size = sizeof("\0__skb"),
.map_type = BPF_MAP_TYPE_ARRAY,
.map_name = "array_type_check_btf",
.key_size = sizeof(int),
.value_size = sizeof(int),
.key_type_id = 1,
.value_type_id = 1,
.max_entries = 4,
.btf_load_err = true,
.err_str = "Invalid name",
},
{
.descr = "struct type (name_off = 0)",
.raw_types = {
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
BTF_TYPE_ENC(0,
BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), 4), /* [2] */
BTF_MEMBER_ENC(NAME_TBD, 1, 0),
BTF_END_RAW,
},
.str_sec = "\0A",
.str_sec_size = sizeof("\0A"),
.map_type = BPF_MAP_TYPE_ARRAY,
.map_name = "struct_type_check_btf",
.key_size = sizeof(int),
.value_size = sizeof(int),
.key_type_id = 1,
.value_type_id = 1,
.max_entries = 4,
},
{
.descr = "struct type (invalid name, invalid identifier)",
.raw_types = {
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
BTF_TYPE_ENC(NAME_TBD,
BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), 4), /* [2] */
BTF_MEMBER_ENC(NAME_TBD, 1, 0),
BTF_END_RAW,
},
.str_sec = "\0A!\0B",
.str_sec_size = sizeof("\0A!\0B"),
.map_type = BPF_MAP_TYPE_ARRAY,
.map_name = "struct_type_check_btf",
.key_size = sizeof(int),
.value_size = sizeof(int),
.key_type_id = 1,
.value_type_id = 1,
.max_entries = 4,
.btf_load_err = true,
.err_str = "Invalid name",
},
{
.descr = "struct member (name_off = 0)",
.raw_types = {
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
BTF_TYPE_ENC(0,
BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), 4), /* [2] */
BTF_MEMBER_ENC(NAME_TBD, 1, 0),
BTF_END_RAW,
},
.str_sec = "\0A",
.str_sec_size = sizeof("\0A"),
.map_type = BPF_MAP_TYPE_ARRAY,
.map_name = "struct_type_check_btf",
.key_size = sizeof(int),
.value_size = sizeof(int),
.key_type_id = 1,
.value_type_id = 1,
.max_entries = 4,
},
{
.descr = "struct member (invalid name, invalid identifier)",
.raw_types = {
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
BTF_TYPE_ENC(NAME_TBD,
BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), 4), /* [2] */
BTF_MEMBER_ENC(NAME_TBD, 1, 0),
BTF_END_RAW,
},
.str_sec = "\0A\0B*",
.str_sec_size = sizeof("\0A\0B*"),
.map_type = BPF_MAP_TYPE_ARRAY,
.map_name = "struct_type_check_btf",
.key_size = sizeof(int),
.value_size = sizeof(int),
.key_type_id = 1,
.value_type_id = 1,
.max_entries = 4,
.btf_load_err = true,
.err_str = "Invalid name",
},
{
.descr = "enum type (name_off = 0)",
.raw_types = {
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
BTF_TYPE_ENC(0,
BTF_INFO_ENC(BTF_KIND_ENUM, 0, 1),
sizeof(int)), /* [2] */
BTF_ENUM_ENC(NAME_TBD, 0),
BTF_END_RAW,
},
.str_sec = "\0A\0B",
.str_sec_size = sizeof("\0A\0B"),
.map_type = BPF_MAP_TYPE_ARRAY,
.map_name = "enum_type_check_btf",
.key_size = sizeof(int),
.value_size = sizeof(int),
.key_type_id = 1,
.value_type_id = 1,
.max_entries = 4,
},
{
.descr = "enum type (invalid name, invalid identifier)",
.raw_types = {
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
BTF_TYPE_ENC(NAME_TBD,
BTF_INFO_ENC(BTF_KIND_ENUM, 0, 1),
sizeof(int)), /* [2] */
BTF_ENUM_ENC(NAME_TBD, 0),
BTF_END_RAW,
},
.str_sec = "\0A!\0B",
.str_sec_size = sizeof("\0A!\0B"),
.map_type = BPF_MAP_TYPE_ARRAY,
.map_name = "enum_type_check_btf",
.key_size = sizeof(int),
.value_size = sizeof(int),
.key_type_id = 1,
.value_type_id = 1,
.max_entries = 4,
.btf_load_err = true,
.err_str = "Invalid name",
},
{
.descr = "enum member (invalid name, name_off = 0)",
.raw_types = {
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
BTF_TYPE_ENC(0,
BTF_INFO_ENC(BTF_KIND_ENUM, 0, 1),
sizeof(int)), /* [2] */
BTF_ENUM_ENC(0, 0),
BTF_END_RAW,
},
.str_sec = "",
.str_sec_size = sizeof(""),
.map_type = BPF_MAP_TYPE_ARRAY,
.map_name = "enum_type_check_btf",
.key_size = sizeof(int),
.value_size = sizeof(int),
.key_type_id = 1,
.value_type_id = 1,
.max_entries = 4,
.btf_load_err = true,
.err_str = "Invalid name",
},
{
.descr = "enum member (invalid name, invalid identifier)",
.raw_types = {
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
BTF_TYPE_ENC(0,
BTF_INFO_ENC(BTF_KIND_ENUM, 0, 1),
sizeof(int)), /* [2] */
BTF_ENUM_ENC(NAME_TBD, 0),
BTF_END_RAW,
},
.str_sec = "\0A!",
.str_sec_size = sizeof("\0A!"),
.map_type = BPF_MAP_TYPE_ARRAY,
.map_name = "enum_type_check_btf",
.key_size = sizeof(int),
.value_size = sizeof(int),
.key_type_id = 1,
.value_type_id = 1,
.max_entries = 4,
.btf_load_err = true,
.err_str = "Invalid name",
},
{
.descr = "arraymap invalid btf key (a bit field)",
.raw_types = {