From: Kui-Feng Lee <thinker.li@gmail.com>
To: bpf@vger.kernel.org, ast@kernel.org, martin.lau@linux.dev,
song@kernel.org, kernel-team@meta.com, andrii@kernel.org
Cc: sinquersw@gmail.com, kuifeng@meta.com,
Kui-Feng Lee <thinker.li@gmail.com>
Subject: [PATCH bpf-next v4 6/9] bpf: limit the number of levels of a nested struct type.
Date: Tue, 7 May 2024 23:32:15 -0700 [thread overview]
Message-ID: <20240508063218.2806447-7-thinker.li@gmail.com> (raw)
In-Reply-To: <20240508063218.2806447-1-thinker.li@gmail.com>
Limit the number of levels looking into struct types to avoid running out
of stack space.
Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
---
kernel/bpf/btf.c | 30 +++++++++++++++++++-----------
1 file changed, 19 insertions(+), 11 deletions(-)
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index bbda24299be2..b4d6a6959b21 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -3534,7 +3534,8 @@ 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.
*
@@ -3545,11 +3546,15 @@ 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;
@@ -3577,7 +3582,8 @@ 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;
@@ -3604,7 +3610,7 @@ 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;
}
@@ -3665,7 +3671,8 @@ 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;
@@ -3684,7 +3691,7 @@ 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;
@@ -3694,7 +3701,7 @@ 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;
@@ -3707,7 +3714,8 @@ 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;
@@ -3720,9 +3728,9 @@ 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;
}
--
2.34.1
next prev parent reply other threads:[~2024-05-08 6:32 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-08 6:32 [PATCH bpf-next v4 0/9] Enable BPF programs to declare arrays of kptr, bpf_rb_root, and bpf_list_head Kui-Feng Lee
2024-05-08 6:32 ` [PATCH bpf-next v4 1/9] bpf: Remove unnecessary checks on the offset of btf_field Kui-Feng Lee
2024-05-08 6:32 ` [PATCH bpf-next v4 2/9] bpf: Remove unnecessary call to btf_field_type_size() Kui-Feng Lee
2024-05-08 6:32 ` [PATCH bpf-next v4 3/9] bpf: refactor btf_find_struct_field() and btf_find_datasec_var() Kui-Feng Lee
2024-05-09 21:25 ` Eduard Zingerman
2024-05-08 6:32 ` [PATCH bpf-next v4 4/9] bpf: create repeated fields for arrays Kui-Feng Lee
2024-05-09 23:13 ` Eduard Zingerman
2024-05-10 0:09 ` Kui-Feng Lee
2024-05-08 6:32 ` [PATCH bpf-next v4 5/9] bpf: look into the types of the fields of a struct type recursively Kui-Feng Lee
2024-05-10 2:36 ` Eduard Zingerman
2024-05-08 6:32 ` Kui-Feng Lee [this message]
2024-05-08 6:32 ` [PATCH bpf-next v4 7/9] selftests/bpf: Test kptr arrays and kptrs in nested struct fields Kui-Feng Lee
2024-05-08 6:32 ` [PATCH bpf-next v4 8/9] selftests/bpf: Test global bpf_rb_root arrays and fields in nested struct types Kui-Feng Lee
2024-05-08 6:32 ` [PATCH bpf-next v4 9/9] selftests/bpf: Test global bpf_list_head arrays Kui-Feng Lee
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