From: Yonghong Song <yonghong.song@linux.dev>
To: Daniel Borkmann <daniel@iogearbox.net>, bpf@vger.kernel.org
Cc: malin89@huawei.com, ast@kernel.org
Subject: Re: [PATCH bpf-next 1/2] bpf: Tighten cgroup storage cookie checks for prog arrays
Date: Wed, 10 Jun 2026 13:14:15 -0700 [thread overview]
Message-ID: <dc831f88-1477-4dcc-9ccd-febea540d725@linux.dev> (raw)
In-Reply-To: <20260610105539.705887-1-daniel@iogearbox.net>
On 6/10/26 3:55 AM, Daniel Borkmann wrote:
> The fix in commit abad3d0bad72 ("bpf: Fix oob access in cgroup local
> storage") is still incomplete. The prog-array compatibility check
> treats a program with no cgroup storage as compatible with any stored
> storage cookie. This allows a storage-less program to bridge a tail
> call chain between an entry program and a storage-using callee even
> though cgroup local storage at runtime still follows the caller's
> context, that is, A -> B(no storage) -> C(storage) path.
>
> Requiring exact cookie equality would break the legitimate case of a
> storage-less leaf program being tail called from a storage-using one.
> Instead, only accept a zero storage cookie if the program cannot
> perform tail calls itself. This keeps A -> B(no storage) working
> while rejecting the A -> B(no storage) -> C(storage) bridge.
>
> Fixes: abad3d0bad72 ("bpf: Fix oob access in cgroup local storage")
> Reported-by: Lin Ma <malin89@huawei.com>
> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
next prev parent reply other threads:[~2026-06-10 20:14 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-10 10:55 [PATCH bpf-next 1/2] bpf: Tighten cgroup storage cookie checks for prog arrays Daniel Borkmann
2026-06-10 10:55 ` [PATCH bpf-next 2/2] selftests/bpf: Cover tail-call cgroup storage prog-array checks Daniel Borkmann
2026-06-10 20:15 ` Yonghong Song
2026-06-10 20:14 ` Yonghong Song [this message]
2026-06-10 23:20 ` [PATCH bpf-next 1/2] bpf: Tighten cgroup storage cookie checks for prog arrays 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=dc831f88-1477-4dcc-9ccd-febea540d725@linux.dev \
--to=yonghong.song@linux.dev \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=malin89@huawei.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox