From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 55B5EC433E0 for ; Sat, 4 Jul 2020 00:14:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3E32420739 for ; Sat, 4 Jul 2020 00:14:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726877AbgGDAOP (ORCPT ); Fri, 3 Jul 2020 20:14:15 -0400 Received: from correo.us.es ([193.147.175.20]:56778 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726787AbgGDAON (ORCPT ); Fri, 3 Jul 2020 20:14:13 -0400 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id 66D91ED5BE for ; Sat, 4 Jul 2020 02:14:11 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 59B0FDA73F for ; Sat, 4 Jul 2020 02:14:11 +0200 (CEST) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id 584DADA72F; Sat, 4 Jul 2020 02:14:11 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id BB69EDA73F; Sat, 4 Jul 2020 02:14:08 +0200 (CEST) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Sat, 04 Jul 2020 02:14:08 +0200 (CEST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/antivirus1-rhel7.int) Received: from localhost.localdomain (unknown [90.77.255.23]) (Authenticated sender: pneira@us.es) by entrada.int (Postfix) with ESMTPA id 8E71642EF532; Sat, 4 Jul 2020 02:14:08 +0200 (CEST) X-SMTPAUTHUS: auth mail.us.es From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org Subject: [PATCH 2/2] netfilter: conntrack: refetch conntrack after nf_conntrack_update() Date: Sat, 4 Jul 2020 02:13:59 +0200 Message-Id: <20200704001359.1304-3-pablo@netfilter.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200704001359.1304-1-pablo@netfilter.org> References: <20200704001359.1304-1-pablo@netfilter.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Virus-Scanned: ClamAV using ClamSMTP Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org __nf_conntrack_update() might refresh the conntrack object that is attached to the skbuff. Otherwise, this triggers UAF. [ 633.200434] ================================================================== [ 633.200472] BUG: KASAN: use-after-free in nf_conntrack_update+0x34e/0x770 [nf_conntrack] [ 633.200478] Read of size 1 at addr ffff888370804c00 by task nfqnl_test/6769 [ 633.200487] CPU: 1 PID: 6769 Comm: nfqnl_test Not tainted 5.8.0-rc2+ #388 [ 633.200490] Hardware name: LENOVO 23259H1/23259H1, BIOS G2ET32WW (1.12 ) 05/30/2012 [ 633.200491] Call Trace: [ 633.200499] dump_stack+0x7c/0xb0 [ 633.200526] ? nf_conntrack_update+0x34e/0x770 [nf_conntrack] [ 633.200532] print_address_description.constprop.6+0x1a/0x200 [ 633.200539] ? _raw_write_lock_irqsave+0xc0/0xc0 [ 633.200568] ? nf_conntrack_update+0x34e/0x770 [nf_conntrack] [ 633.200594] ? nf_conntrack_update+0x34e/0x770 [nf_conntrack] [ 633.200598] kasan_report.cold.9+0x1f/0x42 [ 633.200604] ? call_rcu+0x2c0/0x390 [ 633.200633] ? nf_conntrack_update+0x34e/0x770 [nf_conntrack] [ 633.200659] nf_conntrack_update+0x34e/0x770 [nf_conntrack] [ 633.200687] ? nf_conntrack_find_get+0x30/0x30 [nf_conntrack] Closes: https://bugzilla.netfilter.org/show_bug.cgi?id=1436 Fixes: ee04805ff54a ("netfilter: conntrack: make conntrack userspace helpers work again") Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 79cd9dde457b..f33d72c5b06e 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -2158,6 +2158,8 @@ static int nf_conntrack_update(struct net *net, struct sk_buff *skb) err = __nf_conntrack_update(net, skb, ct, ctinfo); if (err < 0) return err; + + ct = nf_ct_get(skb, &ctinfo); } return nf_confirm_cthelper(skb, ct, ctinfo); -- 2.20.1