ip6_vti: Return an error when adding an existing tunnel.

vti6_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_vti.c b/net/ipv6/ip6_vti.c
index 7f52fd9fa7b0d694dfa35f6246133d379f8ea710..5833a2244467325caff4f75f5740adc809db235b 100644 (file)
--- a/net/ipv6/ip6_vti.c
+++ b/net/ipv6/ip6_vti.c
@@ -253,8 +253,12 @@ static struct ip6_tnl *vti6_locate(struct net *net, struct __ip6_tnl_parm *p,
             (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;