From mboxrd@z Thu Jan 1 00:00:00 1970 From: roy.qing.li@gmail.com Subject: [PATCH 2/2] xfrm6: fix a potential use after free in xfrm6_policy.c Date: Mon, 20 Oct 2014 16:49:14 +0800 Message-ID: <1413794954-16967-2-git-send-email-roy.qing.li@gmail.com> References: <1413794954-16967-1-git-send-email-roy.qing.li@gmail.com> Cc: steffen.klassert@secunet.com To: netdev@vger.kernel.org Return-path: Received: from mail-pd0-f181.google.com ([209.85.192.181]:53153 "EHLO mail-pd0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752904AbaJTItY (ORCPT ); Mon, 20 Oct 2014 04:49:24 -0400 Received: by mail-pd0-f181.google.com with SMTP id z10so4597323pdj.12 for ; Mon, 20 Oct 2014 01:49:23 -0700 (PDT) In-Reply-To: <1413794954-16967-1-git-send-email-roy.qing.li@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Li RongQing pskb_may_pull() maybe change skb->data and make nh and exthdr pointer oboslete, so recompute the nd and exthdr Signed-off-by: Li RongQing --- net/ipv6/xfrm6_policy.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c index ac49f84..115fd3b 100644 --- a/net/ipv6/xfrm6_policy.c +++ b/net/ipv6/xfrm6_policy.c @@ -170,8 +170,10 @@ _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse) case IPPROTO_DCCP: if (!onlyproto && (nh + offset + 4 < skb->data || pskb_may_pull(skb, nh + offset + 4 - skb->data))) { - __be16 *ports = (__be16 *)exthdr; + __be16 *ports; + nh = skb_network_header(skb); + ports = (__be16*)(nh + offset); fl6->fl6_sport = ports[!!reverse]; fl6->fl6_dport = ports[!reverse]; } @@ -180,8 +182,10 @@ _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse) case IPPROTO_ICMPV6: if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) { - u8 *icmp = (u8 *)exthdr; + u8 *icmp; + nh = skb_network_header(skb); + icmp = (u8*)(nh + offset); fl6->fl6_icmp_type = icmp[0]; fl6->fl6_icmp_code = icmp[1]; } @@ -192,8 +196,9 @@ _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse) case IPPROTO_MH: if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) { struct ip6_mh *mh; - mh = (struct ip6_mh *)exthdr; + nh = skb_network_header(skb); + mh = (struct ip6_mh*)(nh + offset); fl6->fl6_mh_type = mh->ip6mh_type; } fl6->flowi6_proto = nexthdr; -- 1.7.10.4