[RFC PATCH] udp: don't rereference dst_entry dev pointer on rcv

Tom Parkin
2013-03-07T22:36:45Z

When a fragmented IP packet is queued during device teardown, it is possible
for the reassembled packet to hit the UDP rcv path with a NULL dst_entry dev
pointer. Drop such packets to prevent an oops.
---
net/ipv4/udp.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 0a073a2..c38a4b1 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1700,6 +1700,9 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
return __udp4_lib_mcast_deliver(net, skb, uh,
saddr, daddr, udptable);

+ if (skb_dst(skb)->dev == NULL)
+ goto drop;
+
sk = __udp4_lib_lookup_skb(skb, uh->source, uh->dest, udptable);

if (sk != NULL) {
--
1.7.9.5