From: Yonghong Song <yonghong.song@linux.dev>
To: Paul Chaignon <paul.chaignon@gmail.com>, bpf@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Eduard Zingerman <eddyz87@gmail.com>,
Martin KaFai Lau <martin.lau@linux.dev>,
netfilter-devel@vger.kernel.org,
Pablo Neira Ayuso <pablo@netfilter.org>,
Jozsef Kadlecsik <kadlec@netfilter.org>,
Petar Penkov <ppenkov@google.com>,
Florian Westphal <fw@strlen.de>
Subject: Re: [PATCH bpf 1/4] bpf: Check flow_dissector ctx accesses are aligned
Date: Fri, 1 Aug 2025 08:52:48 -0700 [thread overview]
Message-ID: <a8e756ca-e9f7-4c56-bd39-3f71e4be9528@linux.dev> (raw)
In-Reply-To: <cc1b036be484c99be45eddf48bd78cc6f72839b1.1754039605.git.paul.chaignon@gmail.com>
On 8/1/25 2:47 AM, Paul Chaignon wrote:
> flow_dissector_is_valid_access doesn't check that the context access is
> aligned. As a consequence, an unaligned access within one of the exposed
> field is considered valid and later rejected by
> flow_dissector_convert_ctx_access when we try to convert it.
>
> The later rejection is problematic because it's reported as a verifier
> bug with a kernel warning and doesn't point to the right instruction in
> verifier logs.
>
> Fixes: d58e468b1112 ("flow_dissector: implements flow dissector BPF hook")
> Reported-by: syzbot+ccac90e482b2a81d74aa@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=ccac90e482b2a81d74aa
> Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
next prev parent reply other threads:[~2025-08-01 15:53 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-01 9:47 [PATCH bpf 1/4] bpf: Check flow_dissector ctx accesses are aligned Paul Chaignon
2025-08-01 9:48 ` [PATCH bpf 2/4] bpf: Check netfilter " Paul Chaignon
2025-08-01 15:54 ` Yonghong Song
2025-08-01 16:06 ` Eduard Zingerman
2025-08-01 9:49 ` [PATCH bpf 3/4] bpf: Improve ctx access verifier error message Paul Chaignon
2025-08-01 16:09 ` Eduard Zingerman
2025-08-01 16:19 ` Paul Chaignon
2025-08-01 16:24 ` Eduard Zingerman
2025-08-01 16:30 ` Yonghong Song
2025-08-01 21:47 ` Alexei Starovoitov
2025-08-02 0:00 ` Yonghong Song
2025-08-01 9:49 ` [PATCH bpf 4/4] selftests/bpf: Test for unaligned flow_dissector ctx access Paul Chaignon
2025-08-01 16:17 ` Eduard Zingerman
2025-08-01 16:33 ` Yonghong Song
2025-08-01 15:52 ` Yonghong Song [this message]
2025-08-01 16:04 ` [PATCH bpf 1/4] bpf: Check flow_dissector ctx accesses are aligned Eduard Zingerman
2025-08-01 16:30 ` patchwork-bot+netdevbpf
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=a8e756ca-e9f7-4c56-bd39-3f71e4be9528@linux.dev \
--to=yonghong.song@linux.dev \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=eddyz87@gmail.com \
--cc=fw@strlen.de \
--cc=kadlec@netfilter.org \
--cc=martin.lau@linux.dev \
--cc=netfilter-devel@vger.kernel.org \
--cc=pablo@netfilter.org \
--cc=paul.chaignon@gmail.com \
--cc=ppenkov@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.