act_nat: fix wild pointer

pskb_may_pull() may change skb pointers, so adjust icmph after pskb_may_pull().

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 0 deletions

diff --git a/net/sched/act_nat.c b/net/sched/act_nat.c
index 724553e8ed7b..ea008f57fc83 100644
--- a/net/sched/act_nat.c
+++ b/net/sched/act_nat.c
@@ -218,6 +218,7 @@ static int tcf_nat(struct sk_buff *skb, struct tc_action *a,
                 if (!pskb_may_pull(skb, ihl + sizeof(*icmph) + sizeof(*iph)))
                         goto drop;
 
+                icmph = (void *)(skb_network_header(skb) + ihl);
                 iph = (void *)(icmph + 1);
                 if (egress)
                         addr = iph->daddr;