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: Hyunwoo Kim <v4bel@xxxxxxxxx> Link: https://lore.kernel.org/bpf/20221223094551.GA1439509@ubuntu Fixes: ceb35b666d42 ("bpf/verifier: Use kmalloc_size_roundup() to match ksize() usage") Cc: Alexei Starovoitov <ast@xxxxxxxxxx> Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Cc: John Fastabend <john.fastabend@xxxxxxxxx> Cc: Andrii Nakryiko <andrii@xxxxxxxxxx> Cc: Martin KaFai Lau <martin.lau@xxxxxxxxx> Cc: Song Liu <song@xxxxxxxxxx> Cc: Yonghong Song <yhs@xxxxxx> Cc: KP Singh <kpsingh@xxxxxxxxxx> Cc: Stanislav Fomichev <sdf@xxxxxxxxxx> Cc: Hao Luo <haoluo@xxxxxxxxxx> Cc: Jiri Olsa <jolsa@xxxxxxxxxx> Cc: bpf@xxxxxxxxxxxxxxx Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> --- kernel/bpf/verifier.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index a5255a0dcbb6..969e61bd6d39 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -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)) @@ -1062,11 +1064,11 @@ 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) - return NULL; + alloc_bytes = max(ksize(orig), kmalloc_size_roundup(bytes)); + dst = krealloc(orig, alloc_bytes, flags); + if (!dst) { + kfree(orig); + return NULL; } memcpy(dst, src, bytes); -- 2.34.1
