[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>
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 8044587..f6a2d92 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2170,8 +2170,19 @@
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;