[INET]: Don't create tunnels with '%' in name.

Four tunnel drivers (ip_gre, ipip, ip6_tunnel and sit) can receive a
pre-defined name for a device from the userspace.  Since these drivers
call the register_netdevice() (rtnl_lock, is held), which does _not_
generate the device's name, this name may contain a '%' character.

Not sure how bad is this to have a device with a '%' in its name, but
all the other places either use the register_netdev(), which call the
dev_alloc_name(), or explicitly call the dev_alloc_name() before
registering, i.e. do not allow for such names.

This had to be prior to the commit 34cc7b, but I forgot to number the
patches and this one got lost, sorry.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 4 deletions

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 2a124e9a1b2..78f43888092 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -238,17 +238,24 @@ static struct ip6_tnl *ip6_tnl_create(struct ip6_tnl_parm *p)
 	if (dev == NULL)
 		goto failed;
 
+	if (strchr(name, '%')) {
+		if (dev_alloc_name(dev, name) < 0)
+			goto failed_free;
+	}
+
 	t = netdev_priv(dev);
 	dev->init = ip6_tnl_dev_init;
 	t->parms = *p;
 
-	if ((err = register_netdevice(dev)) < 0) {
-		free_netdev(dev);
-		goto failed;
-	}
+	if ((err = register_netdevice(dev)) < 0)
+		goto failed_free;
+
 	dev_hold(dev);
 	ip6_tnl_link(t);
 	return t;
+
+failed_free:
+	free_netdev(dev);
 failed:
 	return NULL;
 }