From patchwork Wed Nov 1 18:48:12 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pablo Neira Ayuso X-Patchwork-Id: 833086 X-Patchwork-Delegate: pablo@netfilter.org Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netfilter-devel-owner@vger.kernel.org; receiver=) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3yRy2728ZNz9t2V for ; Thu, 2 Nov 2017 05:49:51 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932685AbdKASs1 (ORCPT ); Wed, 1 Nov 2017 14:48:27 -0400 Received: from mail.us.es ([193.147.175.20]:46498 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933135AbdKASsY (ORCPT ); Wed, 1 Nov 2017 14:48:24 -0400 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id BFA8453AA29 for ; Wed, 1 Nov 2017 19:48:22 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id B11A2DA38E for ; Wed, 1 Nov 2017 19:48:22 +0100 (CET) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id B096BDA38F; Wed, 1 Nov 2017 19:48:22 +0100 (CET) X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on antivirus1-rhel7.int X-Spam-Level: X-Spam-Status: No, score=-108.2 required=7.5 tests=ALL_TRUSTED,BAYES_50, SMTPAUTH_US2,USER_IN_WHITELIST autolearn=disabled version=3.4.1 Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 69A5DDA38E; Wed, 1 Nov 2017 19:48:20 +0100 (CET) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Wed, 01 Nov 2017 19:48:20 +0100 (CET) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/antivirus1-rhel7.int) Received: from salvia.here (129.166.216.87.static.jazztel.es [87.216.166.129]) (Authenticated sender: pneira@us.es) by entrada.int (Postfix) with ESMTPA id 10894402E2EB; Wed, 1 Nov 2017 19:48:19 +0100 (CET) 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: nf_reject_ipv4: Fix use-after-free in send_reset Date: Wed, 1 Nov 2017 19:48:12 +0100 Message-Id: <20171101184812.4813-3-pablo@netfilter.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20171101184812.4813-1-pablo@netfilter.org> References: <20171101184812.4813-1-pablo@netfilter.org> X-Virus-Scanned: ClamAV using ClamSMTP Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org From: Tejaswi Tanikella niph is not updated after pskb_expand_head changes the skb head. It still points to the freed data, which is then used to update tot_len and checksum. This could cause use-after-free poison crash. Update niph, if ip_route_me_harder does not fail. This only affects the interaction with REJECT targets and br_netfilter. Signed-off-by: Tejaswi Tanikella Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/nf_reject_ipv4.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/ipv4/netfilter/nf_reject_ipv4.c b/net/ipv4/netfilter/nf_reject_ipv4.c index eeacbdaf7cdf..5cd06ba3535d 100644 --- a/net/ipv4/netfilter/nf_reject_ipv4.c +++ b/net/ipv4/netfilter/nf_reject_ipv4.c @@ -132,6 +132,8 @@ void nf_send_reset(struct net *net, struct sk_buff *oldskb, int hook) if (ip_route_me_harder(net, nskb, RTN_UNSPEC)) goto free_nskb; + niph = ip_hdr(nskb); + /* "Never happens" */ if (nskb->len > dst_mtu(skb_dst(nskb))) goto free_nskb;