openvswitch: Scrub skb between namespaces

If OVS receives a packet from another namespace, then the packet should
be scrubbed. However, people have already begun to rely on the behaviour
that skb->mark is preserved across namespaces, so retain this one field.

This is mainly to address information leakage between namespaces when
using OVS internal ports, but by placing it in ovs_vport_receive() it is
more generally applicable, meaning it should not be overlooked if other
port types are allowed to be moved into namespaces in future.

Signed-off-by: Joe Stringer <joestringer@nicira.com>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/openvswitch/vport.c b/net/openvswitch/vport.c
index fc5c0b9ccfe9985d5dbb8c91cd8e5fcf225b786d..12a36ac21edaaeddf50442408a1ea27aca975fa0 100644 (file)
--- a/net/openvswitch/vport.c
+++ b/net/openvswitch/vport.c
@@ -444,6 +444,15 @@ int ovs_vport_receive(struct vport *vport, struct sk_buff *skb,
 
        OVS_CB(skb)->input_vport = vport;
        OVS_CB(skb)->mru = 0;
+       if (unlikely(dev_net(skb->dev) != ovs_dp_get_net(vport->dp))) {
+               u32 mark;
+
+               mark = skb->mark;
+               skb_scrub_packet(skb, true);
+               skb->mark = mark;
+               tun_info = NULL;
+       }
+
        /* Extract flow from 'skb' into 'key'. */
        error = ovs_flow_key_extract(tun_info, skb, &key);
        if (unlikely(error)) {