[IFB]: Fix crash on input device removal

The input_device pointer is not refcounted, which means the device may
disappear while packets are queued, causing a crash when ifb passes packets
with a stale skb->dev pointer to netif_rx().

Fix by storing the interface index instead and do a lookup where neccessary.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Acked-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 2 deletions

diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h
index b902d24a3256..02647fe3d74b 100644
--- a/include/net/pkt_cls.h
+++ b/include/net/pkt_cls.h
@@ -352,10 +352,13 @@ tcf_change_indev(struct tcf_proto *tp, char *indev, struct rtattr *indev_tlv)
 static inline int
 tcf_match_indev(struct sk_buff *skb, char *indev)
 {
+        struct net_device *dev;
+
         if (indev[0]) {
-                if  (!skb->input_dev)
+                if  (!skb->iif)
                         return 0;
-                if (strcmp(indev, skb->input_dev->name))
+                dev = __dev_get_by_index(skb->iif);
+                if (!dev || strcmp(indev, dev->name))
                         return 0;
         }