[NET]: Verify gso_type too in gso_segment

We don't want nasty Xen guests to pass a TCPv6 packet in with gso_type set
to TCPv4 or even UDP (or a packet that's both TCP and UDP).
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/af_inet.c

@@ -1106,7 +1106,15 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb, int features)
 	int ihl;
 	int id;
 
-	if (!pskb_may_pull(skb, sizeof(*iph)))
+	if (unlikely(skb_shinfo(skb)->gso_type &
+		     ~(SKB_GSO_TCPV4 |
+		       SKB_GSO_UDP |
+		       SKB_GSO_DODGY |
+		       SKB_GSO_TCP_ECN |
+		       0)))
+		goto out;
+
+	if (unlikely(!pskb_may_pull(skb, sizeof(*iph))))
 		goto out;
 
 	iph = skb->nh.iph;
@@ -1114,7 +1122,7 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb, int features)
 	if (ihl < sizeof(*iph))
 		goto out;
 
-	if (!pskb_may_pull(skb, ihl))
+	if (unlikely(!pskb_may_pull(skb, ihl)))
 		goto out;
 
 	skb->h.raw = __skb_pull(skb, ihl);
@@ -1125,7 +1133,7 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb, int features)
 
 	rcu_read_lock();
 	ops = rcu_dereference(inet_protos[proto]);
-	if (ops && ops->gso_segment)
+	if (likely(ops && ops->gso_segment))
 		segs = ops->gso_segment(skb, features);
 	rcu_read_unlock();
 

net/ipv4/tcp.c

@@ -2170,8 +2170,19 @@ struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
 
 	if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
 		/* Packet is from an untrusted source, reset gso_segs. */
-		int mss = skb_shinfo(skb)->gso_size;
+		int type = skb_shinfo(skb)->gso_type;
+		int mss;
+
+		if (unlikely(type &
+			     ~(SKB_GSO_TCPV4 |
+			       SKB_GSO_DODGY |
+			       SKB_GSO_TCP_ECN |
+			       SKB_GSO_TCPV6 |
+			       0) ||
+			     !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
+			goto out;
 
+		mss = skb_shinfo(skb)->gso_size;
 		skb_shinfo(skb)->gso_segs = (skb->len + mss - 1) / mss;
 
 		segs = NULL;

net/ipv6/ipv6_sockglue.c

@@ -64,6 +64,14 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, int features)
 	struct inet6_protocol *ops;
 	int proto;
 
+	if (unlikely(skb_shinfo(skb)->gso_type &
+		     ~(SKB_GSO_UDP |
+		       SKB_GSO_DODGY |
+		       SKB_GSO_TCP_ECN |
+		       SKB_GSO_TCPV6 |
+		       0)))
+		goto out;
+
 	if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
 		goto out;