[NET]: Make packet reception network namespace safe

This patch modifies every packet receive function
registered with dev_add_pack() to drop packets if they
are not from the initial network namespace.

This should ensure that the various network stacks do
not receive packets in a anything but the initial network
namespace until the code has been converted and is ready
for them.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/net/wan/lapbether.c b/drivers/net/wan/lapbether.c
index 6c302e9dbca2..ca8b3c3cb931 100644
--- a/drivers/net/wan/lapbether.c
+++ b/drivers/net/wan/lapbether.c
@@ -91,6 +91,9 @@ static int lapbeth_rcv(struct sk_buff *skb, struct net_device *dev, struct packe
         int len, err;
         struct lapbethdev *lapbeth;
 
+        if (dev->nd_net != &init_net)
+                goto drop;
+
         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
                 return NET_RX_DROP;