* [PATCH] bpf: Always use maximal size for copy_array()
@ 2022-12-23 18:28 Kees Cook
2022-12-28 23:20 ` patchwork-bot+netdevbpf
0 siblings, 1 reply; 2+ messages in thread
From: Kees Cook @ 2022-12-23 18:28 UTC (permalink / raw)
To: Alexei Starovoitov
Cc: Kees Cook, Hyunwoo Kim, Daniel Borkmann, John Fastabend,
Andrii Nakryiko, Martin KaFai Lau, Song Liu, Yonghong Song,
KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa, bpf,
syzbot+b1e1f7feb407b56d0355, linux-kernel, linux-hardening
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>
---
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
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] bpf: Always use maximal size for copy_array()
2022-12-23 18:28 [PATCH] bpf: Always use maximal size for copy_array() Kees Cook
@ 2022-12-28 23:20 ` patchwork-bot+netdevbpf
0 siblings, 0 replies; 2+ messages in thread
From: patchwork-bot+netdevbpf @ 2022-12-28 23:20 UTC (permalink / raw)
To: Kees Cook
Cc: ast, v4bel, daniel, john.fastabend, andrii, martin.lau, song,
yhs, kpsingh, sdf, haoluo, jolsa, bpf,
syzbot+b1e1f7feb407b56d0355, linux-kernel, linux-hardening
Hello:
This patch was applied to bpf/bpf.git (master)
by Alexei Starovoitov <ast@kernel.org>:
On Fri, 23 Dec 2022 10:28:44 -0800 you wrote:
> 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>
>
> [...]
Here is the summary with links:
- bpf: Always use maximal size for copy_array()
https://git.kernel.org/bpf/bpf/c/45435d8da71f
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
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2022-12-23 18:28 [PATCH] bpf: Always use maximal size for copy_array() Kees Cook
2022-12-28 23:20 ` patchwork-bot+netdevbpf
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