[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>

2 files changed, 18 insertions, 10 deletions

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 906cb1ada4c3..e7821ba7a9a0 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -266,20 +266,24 @@ static struct ip_tunnel * ipgre_tunnel_locate(struct ip_tunnel_parm *parms, int
         if (!dev)
           return NULL;
 
+        if (strchr(name, '%')) {
+                if (dev_alloc_name(dev, name) < 0)
+                        goto failed_free;
+        }
+
         dev->init = ipgre_tunnel_init;
         nt = netdev_priv(dev);
         nt->parms = *parms;
 
-        if (register_netdevice(dev) < 0) {
-                free_netdev(dev);
-                goto failed;
-        }
+        if (register_netdevice(dev) < 0)
+                goto failed_free;
 
         dev_hold(dev);
         ipgre_tunnel_link(nt);
         return nt;
 
-failed:
+failed_free:
+        free_netdev(dev);
         return NULL;
 }
 
diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c
index e77e3b855834..dbaed69de06a 100644
--- a/net/ipv4/ipip.c
+++ b/net/ipv4/ipip.c
@@ -228,20 +228,24 @@ static struct ip_tunnel * ipip_tunnel_locate(struct ip_tunnel_parm *parms, int c
         if (dev == NULL)
                 return NULL;
 
+        if (strchr(name, '%')) {
+                if (dev_alloc_name(dev, name) < 0)
+                        goto failed_free;
+        }
+
         nt = netdev_priv(dev);
         dev->init = ipip_tunnel_init;
         nt->parms = *parms;
 
-        if (register_netdevice(dev) < 0) {
-                free_netdev(dev);
-                goto failed;
-        }
+        if (register_netdevice(dev) < 0)
+                goto failed_free;
 
         dev_hold(dev);
         ipip_tunnel_link(nt);
         return nt;
 
-failed:
+failed_free:
+        free_netdev(dev);
         return NULL;
 }