From b87fb39e399137257a6db3224ea854117e9486e9 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 19 Aug 2012 03:47:30 +0000 Subject: [PATCH] ipv6: gre: fix ip6gre_err() ip6gre_err() miscomputes grehlen (sizeof(ipv6h) is 4 or 8, not 40 as expected), and should take into account 'offset' parameter. Also uses pskb_may_pull() to cope with some fragged skbs Signed-off-by: Eric Dumazet Cc: Dmitry Kozlov Signed-off-by: David S. Miller --- net/ipv6/ip6_gre.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c index a84ad5dc4fcf..424d11a4e7ff 100644 --- a/net/ipv6/ip6_gre.c +++ b/net/ipv6/ip6_gre.c @@ -415,8 +415,8 @@ static void ip6gre_err(struct sk_buff *skb, struct inet6_skb_parm *opt, u8 type, u8 code, int offset, __be32 info) { const struct ipv6hdr *ipv6h = (const struct ipv6hdr *)skb->data; - __be16 *p = (__be16 *)(ipv6h + 1); - int grehlen = sizeof(ipv6h) + 4; + __be16 *p = (__be16 *)(skb->data + offset); + int grehlen = offset + 4; struct ip6_tnl *t; __be16 flags; @@ -432,8 +432,10 @@ static void ip6gre_err(struct sk_buff *skb, struct inet6_skb_parm *opt, } /* If only 8 bytes returned, keyed message will be dropped here */ - if (skb_headlen(skb) < grehlen) + if (!pskb_may_pull(skb, grehlen)) return; + ipv6h = (const struct ipv6hdr *)skb->data; + p = (__be16 *)(skb->data + offset); rcu_read_lock(); -- 2.39.5