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 7f52fd9..5833a22 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;