From: Jiri Pirko <jpirko@redhat.com>
Date: Thu, 14 Aug 2008 16:40:29 +0200
Subject: [net] pppoe: fix skb_unshare_check call position
Message-id: 20080814164029.00299eae@psychotron.englab.brq.redhat.com
O-Subject: [RHEL5.3 patch] BZ459062 pppoe: Fix skb_unshare_check call position [rhel-5.3]
Bugzilla: 459062
RH-Acked-by: David S. Miller <davem@redhat.com>
RH-Acked-by: Thomas Graf <tgraf@redhat.com>

BZ459062

Description:
The skb_unshare_check call needs to be made before pskb_may_pull, not after. Similar like BZ457018.

Upstream status:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=31bac44468257986484703cc09da8a9dcae88a36

Brew build:
http://brewweb.devel.redhat.com/brew/taskinfo?taskID=1431158

Test status:
Booted on x86_64.

Jirka

diff --git a/drivers/net/pppoe.c b/drivers/net/pppoe.c
index 8b21b72..e2cacb4 100644
--- a/drivers/net/pppoe.c
+++ b/drivers/net/pppoe.c
@@ -383,12 +383,12 @@ static int pppoe_rcv(struct sk_buff *skb,
 	struct pppoe_hdr *ph;
 	struct pppox_sock *po;
 
-	if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
-		goto drop;
-
 	if (!(skb = skb_share_check(skb, GFP_ATOMIC))) 
 		goto out;
 
+	if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
+		goto drop;
+
 	ph = (struct pppoe_hdr *) skb->nh.raw;
 
 	po = get_item((unsigned long) ph->sid, eth_hdr(skb)->h_source);