ipv4: ip_tunnel: use net namespace from rtable not socket

The socket parameter might legally be NULL, thus sock_net is sometimes
causing a NULL pointer dereference. Using net_device pointer in dst_entry
is more reliable.

Fixes: b6a7719aedd7e5c ("ipv4: hash net ptr into fragmentation bucket selection")
Reported-by: Rick Jones <rick.jones2@hp.com>
Cc: Rick Jones <rick.jones2@hp.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
index 8c4dcc46acd2932e062faf546331c938b160b0d1..ce63ab21b6cda87f8caea29967a4651b7f78c909 100644 (file)
--- a/net/ipv4/ip_tunnel_core.c
+++ b/net/ipv4/ip_tunnel_core.c
@@ -74,7 +74,8 @@ int iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
        iph->daddr      =       dst;
        iph->saddr      =       src;
        iph->ttl        =       ttl;
-       __ip_select_ident(sock_net(sk), iph, skb_shinfo(skb)->gso_segs ?: 1);
+       __ip_select_ident(dev_net(rt->dst.dev), iph,
+                         skb_shinfo(skb)->gso_segs ?: 1);
 
        err = ip_local_out_sk(sk, skb);
        if (unlikely(net_xmit_eval(err)))