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[23.128.96.18]) by mx.google.com with ESMTP id l12si12864727edk.328.2020.07.14.11.54.57; Tue, 14 Jul 2020 11:55:20 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=o9sxlssV; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730425AbgGNSvo (ORCPT + 99 others); Tue, 14 Jul 2020 14:51:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:48238 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729986AbgGNSvn (ORCPT ); Tue, 14 Jul 2020 14:51:43 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0201122B2A; Tue, 14 Jul 2020 18:51:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594752702; bh=kTY2Fjn4gqXaQmk4478iYSdk+A5ULQRdbyTB/5xmTzo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=o9sxlssVWti3vjFqBFIMLCfV/JepOOFUZ4wH7EIjXfw5EyetujGrH/2hMh5fwKIIT aFnZICgy5bbvJB4al7ckHPT/cwFAaR1mG3LDpg8oO0r7Cpyxva5yVe/0Ox+LibVoDS 5OZlLOb3S3sSXiBn0YmPDNKHrbTyMSoRCTlukTok= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Pablo Neira Ayuso , Sasha Levin Subject: [PATCH 5.4 047/109] netfilter: conntrack: refetch conntrack after nf_conntrack_update() Date: Tue, 14 Jul 2020 20:43:50 +0200 Message-Id: <20200714184107.774838090@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200714184105.507384017@linuxfoundation.org> References: <20200714184105.507384017@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Pablo Neira Ayuso [ Upstream commit d005fbb855d3b5660d62ee5a6bd2d99c13ff8cf3 ] __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 Signed-off-by: Sasha Levin --- 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 48db4aec02dea..200cdad3ff3ab 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -2012,6 +2012,8 @@ 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); -- 2.25.1