From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754547AbbCEHaG (ORCPT ); Thu, 5 Mar 2015 02:30:06 -0500 Received: from mail-la0-f47.google.com ([209.85.215.47]:39291 "EHLO mail-la0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754442AbbCEHaE (ORCPT ); Thu, 5 Mar 2015 02:30:04 -0500 From: Alexander Drozdov To: "David S. Miller" , Alexey Kuznetsov , James Morris , Hideaki YOSHIFUJI , Patrick McHardy Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Alexander Drozdov Subject: [PATCH] ipv4: ip_check_defrag should not assume that skb_network_offset is zero Date: Thu, 5 Mar 2015 10:29:39 +0300 Message-Id: <1425540579-27464-1-git-send-email-al.drozdov@gmail.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ip_check_defrag() may be used by af_packet to defragment outgoing packets. skb_network_offset() of af_packet's outgoing packets is not zero. Signed-off-by: Alexander Drozdov --- net/ipv4/ip_fragment.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c index 2c8d98e..145a50c 100644 --- a/net/ipv4/ip_fragment.c +++ b/net/ipv4/ip_fragment.c @@ -659,27 +659,30 @@ EXPORT_SYMBOL(ip_defrag); struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user) { struct iphdr iph; + int netoff; u32 len; if (skb->protocol != htons(ETH_P_IP)) return skb; - if (skb_copy_bits(skb, 0, &iph, sizeof(iph)) < 0) + netoff = skb_network_offset(skb); + + if (skb_copy_bits(skb, netoff, &iph, sizeof(iph)) < 0) return skb; if (iph.ihl < 5 || iph.version != 4) return skb; len = ntohs(iph.tot_len); - if (skb->len < len || len < (iph.ihl * 4)) + if (skb->len < netoff + len || len < (iph.ihl * 4)) return skb; if (ip_is_fragment(&iph)) { skb = skb_share_check(skb, GFP_ATOMIC); if (skb) { - if (!pskb_may_pull(skb, iph.ihl*4)) + if (!pskb_may_pull(skb, netoff + iph.ihl * 4)) return skb; - if (pskb_trim_rcsum(skb, len)) + if (pskb_trim_rcsum(skb, netoff + len)) return skb; memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); if (ip_defrag(skb, user)) -- 1.9.1