From: David S. Miller <davem@davemloft.net>
Date: Thu, 9 Dec 2010 02:42:23 +0000 (-0800)
Subject: econet: Fix crash in aun_incoming().
X-Git-Tag: firefly_0821_release~9833^2~71^2^2~82
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=b5703e91bc18c166d8b97ee39902d6b9427f8cd1;p=firefly-linux-kernel-4.4.55.git

econet: Fix crash in aun_incoming().

[ Upstream commit 4e085e76cbe558b79b54cbab772f61185879bc64 ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/net/econet/af_econet.c b/net/econet/af_econet.c
index 10d404132c49..172a6a91a214 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;