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| author | Kees Cook <keescook@chromium.org> | 2022-12-23 10:28:44 -0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2022-12-28 14:54:53 -0800 |
| commit | 45435d8da71f9f3e6860e6e6ea9667b6ec17ec64 (patch) | |
| tree | ad5100a0fd034d3ea7a5aeee2bac6c81cf0ee277 /kernel | |
| parent | f90dd663c492124b53bb28db6ff85b50c80ccc32 (diff) | |
| download | lwn-45435d8da71f9f3e6860e6e6ea9667b6ec17ec64.tar.gz lwn-45435d8da71f9f3e6860e6e6ea9667b6ec17ec64.zip | |
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: 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>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/verifier.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 243d06ce6842..85f96c1e9f62 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); |