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bpf: fix NULL deref in btf_type_is_resolve_source_only

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Commit 1dc9285184 ("bpf: kernel side support for BTF Var and DataSec")
added invocations of btf_type_is_resolve_source_only before
btf_type_nosize_or_null which checks for the NULL pointer.
Swap the order of btf_type_nosize_or_null and
btf_type_is_resolve_source_only to make sure the do the NULL pointer
check first.

Fixes: 1dc9285184 ("bpf: kernel side support for BTF Var and DataSec")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Stanislav Fomichev
2019-06-19 12:01:05 -07:00
committed by Daniel Borkmann
parent 56f0f84e69
commit e4f0712021
1 changed files with 6 additions and 6 deletions
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12
kernel/bpf/btf.c
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@@ -1928,8 +1928,8 @@ static int btf_array_resolve(struct btf_verifier_env *env,
/* Check array->index_type */ /* Check array->index_type */
index_type_id = array->index_type; index_type_id = array->index_type;
index_type = btf_type_by_id(btf, index_type_id); index_type = btf_type_by_id(btf, index_type_id);
if (btf_type_is_resolve_source_only(index_type) || if (btf_type_nosize_or_null(index_type) ||
btf_type_nosize_or_null(index_type)) { btf_type_is_resolve_source_only(index_type)) {
btf_verifier_log_type(env, v->t, "Invalid index"); btf_verifier_log_type(env, v->t, "Invalid index");
return -EINVAL; return -EINVAL;
} }
@@ -1948,8 +1948,8 @@ static int btf_array_resolve(struct btf_verifier_env *env,
/* Check array->type */ /* Check array->type */
elem_type_id = array->type; elem_type_id = array->type;
elem_type = btf_type_by_id(btf, elem_type_id); elem_type = btf_type_by_id(btf, elem_type_id);
if (btf_type_is_resolve_source_only(elem_type) || if (btf_type_nosize_or_null(elem_type) ||
btf_type_nosize_or_null(elem_type)) { btf_type_is_resolve_source_only(elem_type)) {
btf_verifier_log_type(env, v->t, btf_verifier_log_type(env, v->t,
"Invalid elem"); "Invalid elem");
return -EINVAL; return -EINVAL;
@@ -2170,8 +2170,8 @@ static int btf_struct_resolve(struct btf_verifier_env *env,
const struct btf_type *member_type = btf_type_by_id(env->btf, const struct btf_type *member_type = btf_type_by_id(env->btf,
member_type_id); member_type_id);
if (btf_type_is_resolve_source_only(member_type) || if (btf_type_nosize_or_null(member_type) ||
btf_type_nosize_or_null(member_type)) { btf_type_is_resolve_source_only(member_type)) {
btf_verifier_log_member(env, v->t, member, btf_verifier_log_member(env, v->t, member,
"Invalid member"); "Invalid member");
return -EINVAL; return -EINVAL;