[PPP] L2TP: Disallow non-UDP datagram sockets

With the addition of UDP-Lite we need to refine the socket check so
that only genuine UDP sockets are allowed through.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/pppol2tp.c b/drivers/net/pppol2tp.c
index 266e8b38fe10004366e78f3bce482add5037b407..ed8ead432d7770b6e209fdfeb2bd336e8dbcf227 100644 (file)
--- a/drivers/net/pppol2tp.c
+++ b/drivers/net/pppol2tp.c
@@ -1326,12 +1326,14 @@ static struct sock *pppol2tp_prepare_tunnel_socket(int fd, u16 tunnel_id,
                goto err;
        }
 
+       sk = sock->sk;
+
        /* Quick sanity checks */
-       err = -ESOCKTNOSUPPORT;
-       if (sock->type != SOCK_DGRAM) {
+       err = -EPROTONOSUPPORT;
+       if (sk->sk_protocol != IPPROTO_UDP) {
                PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
-                      "tunl %hu: fd %d wrong type, got %d, expected %d\n",
-                      tunnel_id, fd, sock->type, SOCK_DGRAM);
+                      "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
+                      tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
                goto err;
        }
        err = -EAFNOSUPPORT;
@@ -1343,7 +1345,6 @@ static struct sock *pppol2tp_prepare_tunnel_socket(int fd, u16 tunnel_id,
        }
 
        err = -ENOTCONN;
-       sk = sock->sk;
 
        /* Check if this socket has already been prepped */
        tunnel = (struct pppol2tp_tunnel *)sk->sk_user_data;