sit: Fix ipip6_tunnel_lookup device matching criteria

[ Upstream commit bc8fc7b8f825ef17a0fb9e68c18ce94fa66ab337 ]

As of 4fddbf5d78 ("sit: strictly restrict incoming traffic to tunnel link device"),
when looking up a tunnel, tunnel's underlying interface (t->parms.link)
is verified to match incoming traffic's ingress device.

However the comparison was incorrectly based on skb->dev->iflink.

Instead, dev->ifindex should be used, which correctly represents the
interface from which the IP stack hands the ipip6 packets.

This allows setting up sit tunnels bound to vlan interfaces (otherwise
incoming ipip6 traffic on the vlan interface was dropped due to
ipip6_tunnel_lookup match failure).

Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index e46fcde5a79b846ac2e96fbdbe6464feb11f4725..ebdf18bbcc02f974d441e030aee12a9a89e1f8a1 100644 (file)
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -101,19 +101,19 @@ static struct ip_tunnel *ipip6_tunnel_lookup(struct net *net,
        for_each_ip_tunnel_rcu(t, sitn->tunnels_r_l[h0 ^ h1]) {
                if (local == t->parms.iph.saddr &&
                    remote == t->parms.iph.daddr &&
-                   (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
+                   (!dev || !t->parms.link || dev->ifindex == t->parms.link) &&
                    (t->dev->flags & IFF_UP))
                        return t;
        }
        for_each_ip_tunnel_rcu(t, sitn->tunnels_r[h0]) {
                if (remote == t->parms.iph.daddr &&
-                   (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
+                   (!dev || !t->parms.link || dev->ifindex == t->parms.link) &&
                    (t->dev->flags & IFF_UP))
                        return t;
        }
        for_each_ip_tunnel_rcu(t, sitn->tunnels_l[h1]) {
                if (local == t->parms.iph.saddr &&
-                   (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
+                   (!dev || !t->parms.link || dev->ifindex == t->parms.link) &&
                    (t->dev->flags & IFF_UP))
                        return t;
        }