[Precise/Quantal][PATCH] bridge: Pull ip header into skb->data before looking into ip header.

[Jesse Sung]

From: Sarveshwar Bandi <sarveshwar.bandi at emulex.com>

BugLink: https://launchpad.net/bugs/1065150

If lower layer driver leaves the ip header in the skb fragment, it needs to
be first pulled into skb->data before inspecting ip header length or ip version
number.

Signed-off-by: Sarveshwar Bandi <sarveshwar.bandi at emulex.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(cherry picked from commit 6caab7b0544e83e6c160b5e80f5a4a7dd69545c7 net.git)

Signed-off-by: Wen-chien Jesse Sung <jesse.sung at canonical.com>
---
 net/bridge/br_netfilter.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
index 577ea5d..7c1745d 100644
--- a/net/bridge/br_netfilter.c
+++ b/net/bridge/br_netfilter.c
@@ -245,6 +245,9 @@ static int br_parse_ip_options(struct sk_buff *skb)
 	struct net_device *dev = skb->dev;
 	u32 len;
 
+	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
+		goto inhdr_error;
+
 	iph = ip_hdr(skb);
 	opt = &(IPCB(skb)->opt);
 
-- 
1.7.9.5