[69/74] econet: Fix crash in aun_incoming().

From: Greg KH
Date: Wed Apr 13 2011 - 11:56:33 EST

2.6.32-longterm review patch. If anyone has any objections, please let us know.


From: David S. Miller <davem@xxxxxxxxxxxxx>

commit 4e085e76cbe558b79b54cbab772f61185879bc64 upstream.

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

Suggested by Eric Dumazet.

Reported-by: Nelson Elhage <nelhage@xxxxxxxxxxx>
Tested-by: Nelson Elhage <nelhage@xxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Moritz Muehlenhoff <jmm@xxxxxxxxxx>
[jmm: Slightly adapted for 2.6.32]
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

net/econet/af_econet.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

--- a/net/econet/af_econet.c
+++ b/net/econet/af_econet.c
@@ -843,9 +843,13 @@ static void aun_incoming(struct sk_buff
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;
struct sk_buff *newskb;
- struct ec_device *edev = skb->dev->ec_ptr;
+ if (dst)
+ edev = dst->dev->ec_ptr;

if (! edev)
goto bad;

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