ip_tunnel: Add missing validation of encap type to ip_tunnel_encap_setup()

The encap->type comes straight from Netlink. Validate it against
max supported encap types just like ip_encap_hlen() already does.

Fixes: a8c5f9 ("ip_tunnel: Ops registration for secondary encap (fou, gue)")
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index 2f498f87e3d8..d3e447936720 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -573,6 +573,9 @@ int ip_tunnel_encap(struct sk_buff *skb, struct ip_tunnel *t,
         if (t->encap.type == TUNNEL_ENCAP_NONE)
                 return 0;
 
+        if (t->encap.type >= MAX_IPTUN_ENCAP_OPS)
+                return -EINVAL;
+
         rcu_read_lock();
         ops = rcu_dereference(iptun_encaps[t->encap.type]);
         if (likely(ops && ops->build_header))