From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755487AbcEQBYj (ORCPT ); Mon, 16 May 2016 21:24:39 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:34344 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755437AbcEQBYd (ORCPT ); Mon, 16 May 2016 21:24:33 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jiri Benc , "David S. Miller" Subject: [PATCH 4.5 025/101] gre: do not pull header in ICMP error processing Date: Mon, 16 May 2016 18:20:30 -0700 Message-Id: <20160517011507.296222821@linuxfoundation.org> X-Mailer: git-send-email 2.8.2 In-Reply-To: <20160517011506.359924439@linuxfoundation.org> References: <20160517011506.359924439@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiri Benc [ Upstream commit b7f8fe251e4609e2a437bd2c2dea01e61db6849c ] iptunnel_pull_header expects that IP header was already pulled; with this expectation, it pulls the tunnel header. This is not true in gre_err. Furthermore, ipv4_update_pmtu and ipv4_redirect expect that skb->data points to the IP header. We cannot pull the tunnel header in this path. It's just a matter of not calling iptunnel_pull_header - we don't need any of its effects. Fixes: bda7bb463436 ("gre: Allow multiple protocol listener for gre protocol.") Signed-off-by: Jiri Benc Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/ip_gre.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) --- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -179,6 +179,7 @@ static __be16 tnl_flags_to_gre_flags(__b return flags; } +/* Fills in tpi and returns header length to be pulled. */ static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi, bool *csum_err) { @@ -238,7 +239,7 @@ static int parse_gre_header(struct sk_bu return -EINVAL; } } - return iptunnel_pull_header(skb, hdr_len, tpi->proto); + return hdr_len; } static void ipgre_err(struct sk_buff *skb, u32 info, @@ -341,7 +342,7 @@ static void gre_err(struct sk_buff *skb, struct tnl_ptk_info tpi; bool csum_err = false; - if (parse_gre_header(skb, &tpi, &csum_err)) { + if (parse_gre_header(skb, &tpi, &csum_err) < 0) { if (!csum_err) /* ignore csum errors. */ return; } @@ -419,6 +420,7 @@ static int gre_rcv(struct sk_buff *skb) { struct tnl_ptk_info tpi; bool csum_err = false; + int hdr_len; #ifdef CONFIG_NET_IPGRE_BROADCAST if (ipv4_is_multicast(ip_hdr(skb)->daddr)) { @@ -428,7 +430,10 @@ static int gre_rcv(struct sk_buff *skb) } #endif - if (parse_gre_header(skb, &tpi, &csum_err) < 0) + hdr_len = parse_gre_header(skb, &tpi, &csum_err); + if (hdr_len < 0) + goto drop; + if (iptunnel_pull_header(skb, hdr_len, tpi.proto) < 0) goto drop; if (ipgre_rcv(skb, &tpi) == PACKET_RCVD)