From: Kees Cook keescook@chromium.org
[ Upstream commit 45435d8da71f9f3e6860e6e6ea9667b6ec17ec64 ]
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@theori.io 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@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: Kees Cook keescook@chromium.org Link: https://lore.kernel.org/r/20221223182836.never.866-kees@kernel.org Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 242fe307032f..b4d5b343c191 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1000,6 +1000,8 @@ 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)) @@ -1008,11 +1010,11 @@ 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);