[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>

2 files changed, 23 insertions, 4 deletions

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 8d157157bf8e..318d4674faa1 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();
 
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 804458712d88..f6a2d9223d07 100644
--- a/net/ipv4/tcp.c
+++ b/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;