diff options
| author | Kui-Feng Lee <thinker.li@gmail.com> | 2024-05-23 10:41:59 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2024-06-03 20:52:42 -0700 |
| commit | f19caf57d80f4432acea61d858d45ce194444389 (patch) | |
| tree | 3c3ae664d5c0edac1fedef8d4989d440830107fe /kernel | |
| parent | 64e8ee814819f21beeeda00d4119221443d77992 (diff) | |
bpf: limit the number of levels of a nested struct type.
Limit the number of levels looking into struct types to avoid running out
of stack space.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
Link: https://lore.kernel.org/r/20240523174202.461236-7-thinker.li@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/btf.c | 30 |
1 files changed, 19 insertions, 11 deletions
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 5e2b231a9af4..7928d920056f 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -3536,7 +3536,8 @@ static int btf_repeat_fields(struct btf_field_info *info, static int btf_find_struct_field(const struct btf *btf, const struct btf_type *t, u32 field_mask, - struct btf_field_info *info, int info_cnt); + struct btf_field_info *info, int info_cnt, + u32 level); /* Find special fields in the struct type of a field. * @@ -3547,11 +3548,15 @@ static int btf_find_struct_field(const struct btf *btf, static int btf_find_nested_struct(const struct btf *btf, const struct btf_type *t, u32 off, u32 nelems, u32 field_mask, struct btf_field_info *info, - int info_cnt) + int info_cnt, u32 level) { int ret, err, i; - ret = btf_find_struct_field(btf, t, field_mask, info, info_cnt); + level++; + if (level >= MAX_RESOLVE_DEPTH) + return -E2BIG; + + ret = btf_find_struct_field(btf, t, field_mask, info, info_cnt, level); if (ret <= 0) return ret; @@ -3579,7 +3584,8 @@ static int btf_find_field_one(const struct btf *btf, int var_idx, u32 off, u32 expected_size, u32 field_mask, u32 *seen_mask, - struct btf_field_info *info, int info_cnt) + struct btf_field_info *info, int info_cnt, + u32 level) { int ret, align, sz, field_type; struct btf_field_info tmp; @@ -3607,7 +3613,7 @@ static int btf_find_field_one(const struct btf *btf, if (expected_size && expected_size != sz * nelems) return 0; ret = btf_find_nested_struct(btf, var_type, off, nelems, field_mask, - &info[0], info_cnt); + &info[0], info_cnt, level); return ret; } @@ -3668,7 +3674,8 @@ static int btf_find_field_one(const struct btf *btf, static int btf_find_struct_field(const struct btf *btf, const struct btf_type *t, u32 field_mask, - struct btf_field_info *info, int info_cnt) + struct btf_field_info *info, int info_cnt, + u32 level) { int ret, idx = 0; const struct btf_member *member; @@ -3687,7 +3694,7 @@ static int btf_find_struct_field(const struct btf *btf, ret = btf_find_field_one(btf, t, member_type, i, off, 0, field_mask, &seen_mask, - &info[idx], info_cnt - idx); + &info[idx], info_cnt - idx, level); if (ret < 0) return ret; idx += ret; @@ -3697,7 +3704,7 @@ static int btf_find_struct_field(const struct btf *btf, static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t, u32 field_mask, struct btf_field_info *info, - int info_cnt) + int info_cnt, u32 level) { int ret, idx = 0; const struct btf_var_secinfo *vsi; @@ -3710,7 +3717,8 @@ static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t, off = vsi->offset; ret = btf_find_field_one(btf, var, var_type, -1, off, vsi->size, field_mask, &seen_mask, - &info[idx], info_cnt - idx); + &info[idx], info_cnt - idx, + level); if (ret < 0) return ret; idx += ret; @@ -3723,9 +3731,9 @@ static int btf_find_field(const struct btf *btf, const struct btf_type *t, int info_cnt) { if (__btf_type_is_struct(t)) - return btf_find_struct_field(btf, t, field_mask, info, info_cnt); + return btf_find_struct_field(btf, t, field_mask, info, info_cnt, 0); else if (btf_type_is_datasec(t)) - return btf_find_datasec_var(btf, t, field_mask, info, info_cnt); + return btf_find_datasec_var(btf, t, field_mask, info, info_cnt, 0); return -EINVAL; } |