From: Matthieu Buffet <matthieu@buffet.re>
To: Bryam Vargas <hexlabsecurity@proton.me>
Cc: "Mickaël Salaün" <mic@digikod.net>,
"Günther Noack" <gnoack@google.com>,
linux-security-module@vger.kernel.org,
"Mikhail Ivanov" <ivanov.mikhail1@huawei-partners.com>,
"Paul Moore" <paul@paul-moore.com>,
"Eric Dumazet" <edumazet@google.com>,
"Neal Cardwell" <ncardwell@google.com>,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
"Matthieu Buffet" <matthieu@buffet.re>
Subject: Re: Landlock: LANDLOCK_ACCESS_NET_CONNECT_TCP bypass via TCP Fast Open
Date: Wed, 17 Jun 2026 20:05:22 +0200 [thread overview]
Message-ID: <20260617180526.15627-1-matthieu@buffet.re> (raw)
In-Reply-To: <20260617.eemahv8ui7Ee@digikod.net>
Hi,
On 6/17/2026 4:22 PM, Mickaël Salaün wrote:
> Thanks for the report. This was previously identified by Mikhail and
> Matthieu, see the related issue:
> https://github.com/landlock-lsm/linux/issues/41
(I worked on a v0 patch for that issue after I first reported it to
Mickaël, missing the fact that it was already documented as a github
issue. Then tried a more generic approach that failed. Here's the v0,
rebased on the beggining of -next to ease backporting, it might be a
good start. For instance, someone with more performance/benchmarking
background might want to add an unlikely() around the MSG_FASTOPEN
condition in the hot code path?)
Have a nice day!
Matthieu Buffet (2):
landlock: fix TCP Fast Open connection bypass
selftests/landlock: Add test for TCP fast open
security/landlock/net.c | 17 +++
tools/testing/selftests/landlock/net_test.c | 155 ++++++++++++++++++++
2 files changed, 172 insertions(+)
base-commit: 0ce4243509d1580349dd0d50624036d6b097e958
--
2.47.3
next prev parent reply other threads:[~2026-06-17 18:05 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-16 20:16 Landlock: LANDLOCK_ACCESS_NET_CONNECT_TCP bypass via TCP Fast Open Bryam Vargas
2026-06-17 14:22 ` Mickaël Salaün
2026-06-17 18:05 ` Matthieu Buffet [this message]
2026-06-17 18:05 ` [RFC PATCH 1/2] landlock: fix TCP Fast Open connection bypass Matthieu Buffet
2026-06-17 18:05 ` [RFC PATCH 2/2] selftests/landlock: Add test for TCP fast open Matthieu Buffet
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