[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, 4 insertions, 0 deletions

diff --git a/net/llc/llc_input.c b/net/llc/llc_input.c
index 099ed8fec145..c40c9b2a345a 100644
--- a/net/llc/llc_input.c
+++ b/net/llc/llc_input.c
@@ -12,6 +12,7 @@
  * See the GNU General Public License for more details.
  */
 #include <linux/netdevice.h>
+#include <net/net_namespace.h>
 #include <net/llc.h>
 #include <net/llc_pdu.h>
 #include <net/llc_sap.h>
@@ -145,6 +146,9 @@ int llc_rcv(struct sk_buff *skb, struct net_device *dev,
         int (*rcv)(struct sk_buff *, struct net_device *,
                    struct packet_type *, struct net_device *);
 
+        if (dev->nd_net != &init_net)
+                goto drop;
+
         /*
          * When the interface is in promisc. mode, drop all the crap that it
          * receives, do not try to analyse it.