econet: Fix crash in aun_incoming().

Unconditional use of skb->dev won't work here,
try to fetch the econet device via skb_dst()->dev
instead.

Suggested by Eric Dumazet.

Reported-by: Nelson Elhage <nelhage@ksplice.com>
Tested-by: Nelson Elhage <nelhage@ksplice.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 1 deletions

diff --git a/net/econet/af_econet.c b/net/econet/af_econet.c
index f180371fa415..15dcc1a586b4 100644
--- a/net/econet/af_econet.c
+++ b/net/econet/af_econet.c
@@ -851,9 +851,13 @@ static void aun_incoming(struct sk_buff *skb, struct aunhdr *ah, size_t len)
 {
         struct iphdr *ip = ip_hdr(skb);
         unsigned char stn = ntohl(ip->saddr) & 0xff;
+        struct dst_entry *dst = skb_dst(skb);
+        struct ec_device *edev = NULL;
         struct sock *sk = NULL;
         struct sk_buff *newskb;
-        struct ec_device *edev = skb->dev->ec_ptr;
+
+        if (dst)
+                edev = dst->dev->ec_ptr;
 
         if (! edev)
                 goto bad;