From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D7D8F4F7999 for ; Wed, 16 Sep 2026 23:53:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789602818; cv=none; b=IGGEWf6nynXmbq/ofBPhHdPeo9O2Gm6yBf0K4WZBSTiDyOrOgI7XgsUMm7TfjTpPyPh+DiWEdDktuZEdP/TqSupkG9kQm/40r3vn2kToGzfxVf3wBg1iofwQPLgMffWlPgT+yiqiPVG5dvUTWKJaTz+MklF12ZhhKrUePmaulrM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789602818; c=relaxed/simple; bh=30S8JeDTCSEux9rjlvKGEClxOXHJc2VTlTVg1dxpWRs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KXIYWpuKT0+jmoO2+l2dFg904DHp2jFL77pcLnOUjiZB4zemtTAgTZHInSw6x7psDbY/7jWSnszifVhjy3N+V79ERs1pbJ1lndey5L/EhFuIt1TastIbwQmMPl9yMtwjPkUvI7yPLQEZyqViDceiyBpGiNm1ki86BuLDX6yIl5A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dxDgNJUb; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="dxDgNJUb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 450441F00898; Wed, 16 Sep 2026 23:53:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789602816; bh=bSeg/O6ST1HIPqGZIETlLguwr9OGwvCUvjwwUvJQXcE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=dxDgNJUbsSt+IkkYl4/GMn6vSDyAeoNwyIqKIsLrS+IBJkb/bxbrgMzYxaYct5vMS LI0MKCQI14cPqVUGuJw/qFkE3N3iD/JFo7+FiFhGxJMIM4QM82BjHR9QsPm2hWDgbL 4X7Bb8acl6Z8/CS21ZwPyZ6K6Z8QkhLKkIOBL6GdwtfqYCH3EEuj3w11EKjDvB4tXt 4Sft/msyWD7USZgtNbozB+NcVL/Fl2Ms+dvhzepGchycoZ3mxeFfhEtSH4wpRzjURK JQdMNitzAjD55OSoCKW3eLTAAmP5ATjrP2/pyoBg3TwM0sKSnvyxDJbUUQRTtAitVe YKgCt5/tEtO/A== From: Sasha Levin To: stable@vger.kernel.org Cc: Chengfeng Ye , Pablo Neira Ayuso , Sasha Levin Subject: [PATCH 6.12.y 2/2] netfilter: cttimeout: prevent UAF during module unload Date: Wed, 16 Sep 2026 19:53:34 -0400 Message-ID: <20260916235334.3313362-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260916235334.3313362-1-sashal@kernel.org> References: <2026091641-overpower-cameo-f985@gregkh> <20260916235334.3313362-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Chengfeng Ye [ Upstream commit fec9b1de0d02de8dafa3cc344bcb91cf28660643 ] nf_ct_set_timeout() protects the timeout hook dereference and policy lookup with rcu_read_lock(). cttimeout_exit(), however, unregisters the per-net operations before it clears the hook. This allows the following interleaving: CPU 0 CPU 1 cttimeout_exit() nf_ct_set_timeout() unregister_pernet_subsys() rcu_read_lock() kfree(pernet) h = nf_ct_timeout_hook h->timeout_find_get() nfct_timeout_pernet() The hook still points to ctnl_timeout_find_get() when CPU 1 looks up the already freed per-net timeout list. KASAN reported: BUG: KASAN: slab-use-after-free in ctnl_timeout_find_get Read of size 8 by task poc/90 Call Trace: ctnl_timeout_find_get+0x271/0x2a0 [nfnetlink_cttimeout] nf_ct_set_timeout+0x7b/0x3c0 xt_ct_tg_check+0x724/0xb20 xt_check_target+0x234/0xa90 do_ipt_set_ctl+0x570/0x1270 Allocated by task 89: __kmalloc_noprof+0x16e/0x460 ops_init+0x6d/0x420 register_pernet_operations+0x2f6/0x670 Freed by task 91: kfree+0x131/0x390 ops_undo_list+0x3d4/0x730 unregister_pernet_operations+0x232/0x490 unregister_pernet_subsys+0x1c/0x30 cttimeout_exit+0x52/0x970 [nfnetlink_cttimeout] Clear the hook and wait for existing readers before unregistering the per-net operations. This blocks new policy lookups and ensures readers that observed the hook finish before the per-net storage is freed. Fixes: ebfbe67568a7 ("netfilter: cttimeout: use net_generic infra") Cc: stable@vger.kernel.org Signed-off-by: Chengfeng Ye Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin --- net/netfilter/nfnetlink_cttimeout.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/netfilter/nfnetlink_cttimeout.c b/net/netfilter/nfnetlink_cttimeout.c index 12648d7d02ac6..639b1d4efd7ac 100644 --- a/net/netfilter/nfnetlink_cttimeout.c +++ b/net/netfilter/nfnetlink_cttimeout.c @@ -659,9 +659,9 @@ static void __exit cttimeout_exit(void) { nfnetlink_subsys_unregister(&cttimeout_subsys); - unregister_pernet_subsys(&cttimeout_ops); RCU_INIT_POINTER(nf_ct_timeout_hook, NULL); synchronize_net(); + unregister_pernet_subsys(&cttimeout_ops); } module_init(cttimeout_init); -- 2.53.0