[Patch net-next] ipip: fix a regression in ioctl

[Cong Wang <amwang@redhat.com>]

From: Cong Wang <amwang@redhat.com>

This is a regression introduced by 
commit fd58156e456d9f68fe0448 (IPIP: Use ip-tunneling code.)

Similar to GRE tunnel, previously we only check the parameters
for SIOCADDTUNNEL and SIOCCHGTUNNEL, after that commit, the
check is moved for all commands.

So, just check for SIOCADDTUNNEL and SIOCCHGTUNNEL.

Also, the check for i_key, o_key etc. is suspicious too,
which did not exist before.

Cc: Pravin B Shelar <pshelar@nicira.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>

---
diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c
index e6905fb..9d6ca81 100644
--- a/net/ipv4/ipip.c
+++ b/net/ipv4/ipip.c
@@ -244,11 +244,11 @@ ipip_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 	if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 		return -EFAULT;
 
-	if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP ||
-			p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
-		return -EINVAL;
-	if (p.i_key || p.o_key || p.i_flags || p.o_flags)
-		return -EINVAL;
+	if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) {
+		if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP ||
+		    p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
+			return -EINVAL;
+	}
 	if (p.iph.ttl)
 		p.iph.frag_off |= htons(IP_DF);