From: Eduard Zingerman <eddyz87@gmail.com>
To: Kohei Enju <enjuk@amazon.com>,
bpf@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
John Fastabend <john.fastabend@gmail.com>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@fomichev.me>,
Hao Luo <haoluo@google.com>, Jiri Olsa <jolsa@kernel.org>,
Peilin Ye <yepeilin@google.com>,
Ilya Leoshkevich <iii@linux.ibm.com>,
Kuniyuki Iwashima <kuniyu@amazon.com>,
kohei.enju@gmail.com,
syzbot+a5964227adc0f904549c@syzkaller.appspotmail.com
Subject: Re: [PATCH v2 bpf-next 1/2] bpf: Fix out-of-bounds read in check_atomic_load/store()
Date: Fri, 21 Mar 2025 15:16:43 -0700 [thread overview]
Message-ID: <44d4adae6a5398dcd97afbe2c922f8c9a71598f2.camel@gmail.com> (raw)
In-Reply-To: <20250321110010.95217-5-enjuk@amazon.com>
On Fri, 2025-03-21 at 19:59 +0900, Kohei Enju wrote:
> syzbot reported the following splat [0].
>
> In check_atomic_load/store(), register validity is not checked before
> atomic_ptr_type_ok(). This causes the out-of-bounds read in is_ctx_reg()
> called from atomic_ptr_type_ok() when the register number is MAX_BPF_REG
> or greater.
>
> Let's call check_load_mem()/check_store_reg() before atomic_ptr_type_ok()
> to avoid the OOB read.
[...]
> Memory state around the buggy address:
> ffff888141b0d580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ffff888141b0d600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> >ffff888141b0d680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ^
> ffff888141b0d700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ffff888141b0d780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>
> Reported-by: syzbot+a5964227adc0f904549c@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=a5964227adc0f904549c
> Tested-by: syzbot+a5964227adc0f904549c@syzkaller.appspotmail.com
> Fixes: e24bbad29a8d ("bpf: Introduce load-acquire and store-release instructions")
> Fixes: ff3afe5da998 ("selftests/bpf: Add selftests for load-acquire and store-release instructions")
> Signed-off-by: Kohei Enju <enjuk@amazon.com>
> ---
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
[...]
next prev parent reply other threads:[~2025-03-21 22:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-21 10:59 [PATCH v2 bpf-next 0/2] bpf: Fix OOB read and add tests for load-acquire/store-release Kohei Enju
2025-03-21 10:59 ` [PATCH v2 bpf-next 1/2] bpf: Fix out-of-bounds read in check_atomic_load/store() Kohei Enju
2025-03-21 22:16 ` Eduard Zingerman [this message]
2025-03-21 10:59 ` [PATCH v2 bpf-next 2/2] selftests/bpf: Add selftests for load-acquire/store-release when register number is invalid Kohei Enju
2025-03-21 22:24 ` Eduard Zingerman
2025-03-22 2:48 ` Kohei Enju
2025-03-22 3:17 ` Eduard Zingerman
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