From: Jakub Kicinski <kuba@kernel.org>
To: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: netdev@vger.kernel.org, stable@vger.kernel.org, vega@nebusec.ai,
Victor Nogueira <victor@mojatatu.com>,
Davide Caratti <dcaratti@redhat.com>,
Jiri Pirko <jiri@resnulli.us>,
"David S . Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>, Simon Horman <horms@kernel.org>
Subject: Re: [PATCH net] net/sched: act_api: fix TOCTOU NULL deref on a->goto_chain
Date: Mon, 10 Aug 2026 16:45:36 -0700 [thread overview]
Message-ID: <20260810164536.6ecf043d@kernel.org> (raw)
In-Reply-To: <20260809090928.868186-1-jhs@mojatatu.com>
On Sun, 9 Aug 2026 05:09:28 -0400 Jamal Hadi Salim wrote:
> tcf_action_exec() handles TC_ACT_GOTO_CHAIN by first checking
> rcu_access_pointer(a->goto_chain) and then calling
> tcf_action_goto_chain_exec(), which does a second, independent
> rcu_dereference_bh(a->goto_chain) read and immediately dereferences
> chain->filter_chain. A concurrent tcf_action_set_ctrlact() (e.g. the gact
> replace path) can clear a->goto_chain between the two reads, so the second
> read returns NULL and tcf_action_goto_chain_exec() dereferences NULL.
FWIW *shiko suggests another tweak but looks orthogonal, LMK if you
disagree:
https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260809090928.868186-1-jhs@mojatatu.com
(the patch is "too fresh" for me to apply right now anyway)
next prev parent reply other threads:[~2026-08-10 23:45 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-09 9:09 [PATCH net] net/sched: act_api: fix TOCTOU NULL deref on a->goto_chain Jamal Hadi Salim
2026-08-10 7:57 ` Davide Caratti
2026-08-10 23:45 ` Jakub Kicinski [this message]
-- strict thread matches above, loose matches on Subject: below --
2026-08-09 9:07 Jamal Hadi Salim
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