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 076C64B44A1; Thu, 17 Sep 2026 15:51:56 +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=1789660317; cv=none; b=K6GswUc1MP+z55A4BKylIvp/Q/+4fFLJ/nGCrt2nyK2Gf47qVb5nlEeHqcUcYcxkk/rlXgpakGLp/Q0zBSYfwrKK1R0m1JBsB1Wsw6Wn6BatznjKNZWvi5tiO7kInsEFDTGHl6EemAchVAJpxkZFw6LpExUOYmGU5N1aZ8YS+pM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789660317; c=relaxed/simple; bh=TONYp2G+vQhZLaVYb44f0bMsBbAEOzfjuzdXCi1eINI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KpIzBQqwF3fgZUiol9F0RxupUMZ7UNtX422dKPd/bL8eQoONf9XSjk7v90MBgp9PUuRRYzG9XHAIDOgXKsnxNYuue+zzdVqEnfzTAIRwTAESktlumPzlQfgLuT87vB5Ul94eJLVXB66JhA6jiTobYdP15+o5mx2aNru00OMTLLQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=0nRbLayU; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="0nRbLayU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5E8371F000FF; Thu, 17 Sep 2026 15:51:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789660315; bh=BkQV0Szq2oY+4Dr7FbP6NV9V0HuqRDxKUbEWoxje8v0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=0nRbLayUmXjV5xU/MuSA5YBFDFLBvNH/Flo+9nWyxd26f4jkAJksKtSkxCpKHDwRd JE1T13zjMDY4mtjJgfg7XzJNYjPt/uZwVptOEFDqxYTTpq9NBDDupQoXdThWNiEC2/ 81Yrt9+7fYyf1KrIjyVE9t5kx30qLCAi6XuIADCo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chengfeng Ye , Pablo Neira Ayuso Subject: [PATCH 7.2 552/733] netfilter: cttimeout: prevent UAF during module unload Date: Thu, 17 Sep 2026 16:14:20 +0100 Message-ID: <20260917151406.025162895@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260917151350.597953846@linuxfoundation.org> References: <20260917151350.597953846@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chengfeng Ye commit fec9b1de0d02de8dafa3cc344bcb91cf28660643 upstream. 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: Greg Kroah-Hartman --- net/netfilter/nfnetlink_cttimeout.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/netfilter/nfnetlink_cttimeout.c +++ b/net/netfilter/nfnetlink_cttimeout.c @@ -652,9 +652,9 @@ 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);