[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>

1 files changed, 11 insertions, 3 deletions

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 8d157157bf8..318d4674faa 100644
--- a/net/ipv4/af_inet.c
+++ b/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();