ip6_tunnel: Return an error when adding an existing tunnel.

ip6_tnl_locate() should not return an existing tunnel if
create is true. Otherwise it is possible to add the same
tunnel multiple times without getting an error.

So return NULL if the tunnel that should be created already
exists.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index f9de5a69507252a12cbf1efffbf416721d9c871a..69a84b464009cc3192d42acc8a2c4d1e8419ca61 100644 (file)
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -364,8 +364,12 @@ static struct ip6_tnl *ip6_tnl_locate(struct net *net,
             (t = rtnl_dereference(*tp)) != NULL;
             tp = &t->next) {
                if (ipv6_addr_equal(local, &t->parms.laddr) &&
-                   ipv6_addr_equal(remote, &t->parms.raddr))
+                   ipv6_addr_equal(remote, &t->parms.raddr)) {
+                       if (create)
+                               return NULL;
+
                        return t;
+               }
        }
        if (!create)
                return NULL;