Commit 45435d8d authored by Kees Cook's avatar Kees Cook Committed by Alexei Starovoitov
Browse files

bpf: Always use maximal size for copy_array() 



Instead of counting on prior allocations to have sized allocations to
the next kmalloc bucket size, always perform a krealloc that is at least
ksize(dst) in size (which is a no-op), so the size can be correctly
tracked by all the various allocation size trackers (KASAN,
__alloc_size, etc).

Reported-by: default avatarHyunwoo Kim <v4bel@theori.io>
Link: https://lore.kernel.org/bpf/20221223094551.GA1439509@ubuntu


Fixes: ceb35b66 ("bpf/verifier: Use kmalloc_size_roundup() to match ksize() usage")
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Song Liu <song@kernel.org>
Cc: Yonghong Song <yhs@fb.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Stanislav Fomichev <sdf@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: bpf@vger.kernel.org
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221223182836.never.866-kees@kernel.org


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent f90dd663

kernel/bpf/verifier.c

+7 −5
Original line number Diff line number Diff line
@@ -1054,6 +1054,8 @@ static void print_insn_state(struct bpf_verifier_env *env, 
 */

static void *copy_array(void *dst, const void *src, size_t n, size_t size, gfp_t flags)

{

	size_t alloc_bytes;

	void *orig = dst;

	size_t bytes;



	if (ZERO_OR_NULL_PTR(src))
@@ -1062,10 +1064,10 @@ static void *copy_array(void *dst, const void *src, size_t n, size_t size, gfp_t 
	if (unlikely(check_mul_overflow(n, size, &bytes)))

		return NULL;



	if (ksize(dst) < ksize(src)) {

		kfree(dst);

		dst = kmalloc_track_caller(kmalloc_size_roundup(bytes), flags);

		if (!dst)

	alloc_bytes = max(ksize(orig), kmalloc_size_roundup(bytes));

	dst = krealloc(orig, alloc_bytes, flags);

	if (!dst) {

		kfree(orig);

		return NULL;

	}