From: Isaku Yamahata <yamahata@valinux.co.jp>
Date: Thu, 20 Dec 2012 15:12:52 +0000 (+0000)
Subject: ip_gre: make ipgre_tunnel_xmit() not parse network header as IP unconditionally
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=412ed94744d16806fbec3bd250fd94e71cde5a1f;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git

ip_gre: make ipgre_tunnel_xmit() not parse network header as IP unconditionally

ipgre_tunnel_xmit() parses network header as IP unconditionally.
But transmitting packets are not always IP packet. For example such packet
can be sent by packet socket with sockaddr_ll.sll_protocol set.
So make the function check if skb->protocol is IP.

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index a85ae2f7a21c..8fcf0ed76548 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -760,7 +760,10 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
 
 	if (dev->header_ops && dev->type == ARPHRD_IPGRE) {
 		gre_hlen = 0;
-		tiph = (const struct iphdr *)skb->data;
+		if (skb->protocol == htons(ETH_P_IP))
+			tiph = (const struct iphdr *)skb->data;
+		else
+			tiph = &tunnel->parms.iph;
 	} else {
 		gre_hlen = tunnel->hlen;
 		tiph = &tunnel->parms.iph;