From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161951Ab3LFW3d (ORCPT ); Fri, 6 Dec 2013 17:29:33 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:60674 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161075Ab3LFVxD (ORCPT ); Fri, 6 Dec 2013 16:53:03 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Meelis Roos , Steffen Klassert Subject: [PATCH 3.12 60/83] xfrm: Fix null pointer dereference when decoding sessions Date: Fri, 6 Dec 2013 13:51:50 -0800 Message-Id: <20131206214645.634826443@linuxfoundation.org> X-Mailer: git-send-email 1.8.5.1.67.gb00d244 In-Reply-To: <20131206214640.002320724@linuxfoundation.org> References: <20131206214640.002320724@linuxfoundation.org> User-Agent: quilt/0.60-8.1.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Steffen Klassert [ Upstream commit 84502b5ef9849a9694673b15c31bd3ac693010ae ] On some codepaths the skb does not have a dst entry when xfrm_decode_session() is called. So check for a valid skb_dst() before dereferencing the device interface index. We use 0 as the device index if there is no valid skb_dst(), or at reverse decoding we use skb_iif as device interface index. Bug was introduced with git commit bafd4bd4dc ("xfrm: Decode sessions with output interface."). Reported-by: Meelis Roos Tested-by: Meelis Roos Signed-off-by: Steffen Klassert Signed-off-by: Greg Kroah-Hartman --- net/ipv4/xfrm4_policy.c | 6 +++++- net/ipv6/xfrm6_policy.c | 6 +++++- 2 files changed, 10 insertions(+), 2 deletions(-) --- a/net/ipv4/xfrm4_policy.c +++ b/net/ipv4/xfrm4_policy.c @@ -104,10 +104,14 @@ _decode_session4(struct sk_buff *skb, st const struct iphdr *iph = ip_hdr(skb); u8 *xprth = skb_network_header(skb) + iph->ihl * 4; struct flowi4 *fl4 = &fl->u.ip4; + int oif = 0; + + if (skb_dst(skb)) + oif = skb_dst(skb)->dev->ifindex; memset(fl4, 0, sizeof(struct flowi4)); fl4->flowi4_mark = skb->mark; - fl4->flowi4_oif = skb_dst(skb)->dev->ifindex; + fl4->flowi4_oif = reverse ? skb->skb_iif : oif; if (!ip_is_fragment(iph)) { switch (iph->protocol) { --- a/net/ipv6/xfrm6_policy.c +++ b/net/ipv6/xfrm6_policy.c @@ -135,10 +135,14 @@ _decode_session6(struct sk_buff *skb, st struct ipv6_opt_hdr *exthdr; const unsigned char *nh = skb_network_header(skb); u8 nexthdr = nh[IP6CB(skb)->nhoff]; + int oif = 0; + + if (skb_dst(skb)) + oif = skb_dst(skb)->dev->ifindex; memset(fl6, 0, sizeof(struct flowi6)); fl6->flowi6_mark = skb->mark; - fl6->flowi6_oif = skb_dst(skb)->dev->ifindex; + fl6->flowi6_oif = reverse ? skb->skb_iif : oif; fl6->daddr = reverse ? hdr->saddr : hdr->daddr; fl6->saddr = reverse ? hdr->daddr : hdr->saddr;