ip_tunnel: Do not use stale inner_iph pointer.

While sending packet skb_cow_head() can change skb header which
invalidates inner_iph pointer to skb header. Following patch
avoid using it. Found by code inspection.

This bug was introduced by commit 0e6fbc5b6c6218 (ip_tunnels: extend
iptunnel_xmit()).

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index ac9fabe..d3fbad4 100644 (file)
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -623,6 +623,7 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
                        tunnel->err_count = 0;
        }
 
+       tos = ip_tunnel_ecn_encap(tos, inner_iph, skb);
        ttl = tnl_params->ttl;
        if (ttl == 0) {
                if (skb->protocol == htons(ETH_P_IP))
@@ -651,8 +652,7 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
        }
 
        err = iptunnel_xmit(rt, skb, fl4.saddr, fl4.daddr, protocol,
-                           ip_tunnel_ecn_encap(tos, inner_iph, skb), ttl, df,
-                           !net_eq(tunnel->net, dev_net(dev)));
+                           tos, ttl, df, !net_eq(tunnel->net, dev_net(dev)));
        iptunnel_xmit_stats(err, &dev->stats, dev->tstats);
 
        return;