[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>

3 files changed, 16 insertions, 0 deletions

diff --git a/drivers/net/wan/hdlc.c b/drivers/net/wan/hdlc.c
index 65ad2e24caf0..3b57350eacca 100644
--- a/drivers/net/wan/hdlc.c
+++ b/drivers/net/wan/hdlc.c
@@ -36,6 +36,7 @@
 #include <linux/rtnetlink.h>
 #include <linux/notifier.h>
 #include <linux/hdlc.h>
+#include <net/net_namespace.h>
 
 
 static const char* version = "HDLC support module revision 1.21";
@@ -66,6 +67,12 @@ static int hdlc_rcv(struct sk_buff *skb, struct net_device *dev,
                     struct packet_type *p, struct net_device *orig_dev)
 {
         struct hdlc_device_desc *desc = dev_to_desc(dev);
+
+        if (dev->nd_net != &init_net) {
+                kfree_skb(skb);
+                return 0;
+        }
+
         if (desc->netif_rx)
                 return desc->netif_rx(skb);
 
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;
 
diff --git a/drivers/net/wan/syncppp.c b/drivers/net/wan/syncppp.c
index 67fc67cfd452..5c71af6ea3a5 100644
--- a/drivers/net/wan/syncppp.c
+++ b/drivers/net/wan/syncppp.c
@@ -51,6 +51,7 @@
 #include <linux/spinlock.h>
 #include <linux/rcupdate.h>
 
+#include <net/net_namespace.h>
 #include <net/syncppp.h>
 
 #include <asm/byteorder.h>
@@ -1445,6 +1446,11 @@ static void sppp_print_bytes (u_char *p, u16 len)
 
 static int sppp_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *p, struct net_device *orig_dev)
 {
+        if (dev->nd_net != &init_net) {
+                kfree_skb(skb);
+                return 0;
+        }
+
         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
                 return NET_RX_DROP;
         sppp_input(dev,skb);