[PATCH 4.9 192/310] sit: reload iphdr in ipip6_rcv

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Haishuang Yan <yanhaishuang@xxxxxxxxxxxxxxxxxxxx>


[ Upstream commit b699d0035836f6712917a41e7ae58d84359b8ff9 ]

Since iptunnel_pull_header() can call pskb_may_pull(),
we must reload any pointer that was related to skb->head.

Fixes: a09a4c8dd1ec ("tunnels: Remove encapsulation offloads on decap")
Signed-off-by: Haishuang Yan <yanhaishuang@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/ipv6/sit.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -657,6 +657,7 @@ static int ipip6_rcv(struct sk_buff *skb
 		if (iptunnel_pull_header(skb, 0, htons(ETH_P_IPV6),
 		    !net_eq(tunnel->net, dev_net(tunnel->dev))))
 			goto out;
+		iph = ip_hdr(skb);
 
 		err = IP_ECN_decapsulate(iph, skb);
 		if (unlikely(err)) {