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Commit e4f07120 authored by Stanislav Fomichev's avatar Stanislav Fomichev Committed by Daniel Borkmann
Browse files

bpf: fix NULL deref in btf_type_is_resolve_source_only 



Commit 1dc92851 ("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: 1dc92851 ("bpf: kernel side support for BTF Var and DataSec")
Reported-by: default avatarsyzbot <syzkaller@googlegroups.com>
Signed-off-by: default avatarStanislav Fomichev <sdf@google.com>
Acked-by: default avatarAndrii Nakryiko <andriin@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 56f0f84e

kernel/bpf/btf.c

+6 −6
Original line number Diff line number Diff line
@@ -1928,8 +1928,8 @@ static int btf_array_resolve(struct btf_verifier_env *env, 
	/* Check array->index_type */

	index_type_id = array->index_type;

	index_type = btf_type_by_id(btf, index_type_id);

	if (btf_type_is_resolve_source_only(index_type) ||

	    btf_type_nosize_or_null(index_type)) {

	if (btf_type_nosize_or_null(index_type) ||

	    btf_type_is_resolve_source_only(index_type)) {

		btf_verifier_log_type(env, v->t, "Invalid index");

		return -EINVAL;

	}
@@ -1948,8 +1948,8 @@ static int btf_array_resolve(struct btf_verifier_env *env, 
	/* Check array->type */

	elem_type_id = array->type;

	elem_type = btf_type_by_id(btf, elem_type_id);

	if (btf_type_is_resolve_source_only(elem_type) ||

	    btf_type_nosize_or_null(elem_type)) {

	if (btf_type_nosize_or_null(elem_type) ||

	    btf_type_is_resolve_source_only(elem_type)) {

		btf_verifier_log_type(env, v->t,

				      "Invalid elem");

		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,

								member_type_id);



		if (btf_type_is_resolve_source_only(member_type) ||

		    btf_type_nosize_or_null(member_type)) {

		if (btf_type_nosize_or_null(member_type) ||

		    btf_type_is_resolve_source_only(member_type)) {

			btf_verifier_log_member(env, v->t, member,

						"Invalid member");

			return -EINVAL;