bridge: Partially disable netpoll support

The new netpoll code in bridging contains use-after-free bugs
that are non-trivial to fix.

This patch fixes this by removing the code that uses skbs after
they're freed.

As a consequence, this means that we can no longer call bridge
from the netpoll path, so this patch also removes the controller
function in order to disable netpoll.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Thanks,
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 1 insertions, 31 deletions

diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index eedf2c94820e..753fc4221f3c 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -217,14 +217,6 @@ static bool br_devices_support_netpoll(struct net_bridge *br)
         return count != 0 && ret;
 }
 
-static void br_poll_controller(struct net_device *br_dev)
-{
-        struct netpoll *np = br_dev->npinfo->netpoll;
-
-        if (np->real_dev != br_dev)
-                netpoll_poll_dev(np->real_dev);
-}
-
 void br_netpoll_cleanup(struct net_device *dev)
 {
         struct net_bridge *br = netdev_priv(dev);
@@ -295,7 +287,6 @@ static const struct net_device_ops br_netdev_ops = {
         .ndo_do_ioctl            = br_dev_ioctl,
 #ifdef CONFIG_NET_POLL_CONTROLLER
         .ndo_netpoll_cleanup     = br_netpoll_cleanup,
-        .ndo_poll_controller     = br_poll_controller,
 #endif
 };
 
diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
index a4e72a89e4ff..595da45f9088 100644
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -50,14 +50,7 @@ int br_dev_queue_push_xmit(struct sk_buff *skb)
                         kfree_skb(skb);
                 else {
                         skb_push(skb, ETH_HLEN);
-
-#ifdef CONFIG_NET_POLL_CONTROLLER
-                        if (unlikely(skb->dev->priv_flags & IFF_IN_NETPOLL)) {
-                                netpoll_send_skb(skb->dev->npinfo->netpoll, skb);
-                                skb->dev->priv_flags &= ~IFF_IN_NETPOLL;
-                        } else
-#endif
-                                dev_queue_xmit(skb);
+                        dev_queue_xmit(skb);
                 }
         }
 
@@ -73,23 +66,9 @@ int br_forward_finish(struct sk_buff *skb)
 
 static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
 {
-#ifdef CONFIG_NET_POLL_CONTROLLER
-        struct net_bridge *br = to->br;
-        if (unlikely(br->dev->priv_flags & IFF_IN_NETPOLL)) {
-                struct netpoll *np;
-                to->dev->npinfo = skb->dev->npinfo;
-                np = skb->dev->npinfo->netpoll;
-                np->real_dev = np->dev = to->dev;
-                to->dev->priv_flags |= IFF_IN_NETPOLL;
-        }
-#endif
         skb->dev = to->dev;
         NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
                 br_forward_finish);
-#ifdef CONFIG_NET_POLL_CONTROLLER
-        if (skb->dev->npinfo)
-                skb->dev->npinfo->netpoll->dev = br->dev;
-#endif
 }
 
 static void __br_forward(const struct net_bridge_port *to, struct sk_buff *skb)