vti: don't allow to add the same tunnel twice

[ Upstream commit 8d89dcdf80d88007647945a753821a06eb6cc5a5 ]

Before the patch, it was possible to add two times the same tunnel:
ip l a vti1 type vti remote 10.16.0.121 local 10.16.0.249 key 41
ip l a vti2 type vti remote 10.16.0.121 local 10.16.0.249 key 41

It was possible, because ip_tunnel_newlink() calls ip_tunnel_find() with the
argument dev->type, which was set only later (when calling ndo_init handler
in register_netdevice()). Let's set this type in the setup handler, which is
called before newlink handler.

Introduced by commit b9959fd3b0fa ("vti: switch to new ip tunnel code").

CC: Cong Wang <amwang@redhat.com>
CC: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c
index feb19db62359ea30dead79f2a1afaed2e1d926d1..4ec34275160b7b6185ba0152fdbf972e4e72cbc7 100644 (file)
--- a/net/ipv4/ip_vti.c
+++ b/net/ipv4/ip_vti.c
@@ -579,9 +579,9 @@ static void vti_dev_free(struct net_device *dev)
 static void vti_tunnel_setup(struct net_device *dev)
 {
        dev->netdev_ops         = &vti_netdev_ops;
+       dev->type               = ARPHRD_TUNNEL;
        dev->destructor         = vti_dev_free;
 
-       dev->type               = ARPHRD_TUNNEL;
        dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
        dev->mtu                = ETH_DATA_LEN;
        dev->flags              = IFF_NOARP;