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

From: Pavel Emelyanov <[email-masked]>
Date: Thu, 21 Feb 2008 15:05:27 +0300

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() after this 
(rtnl_lock is held), the device's 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(),
or explicitly call dev_alloc_name() before registering, i.e. 
do not allow for such names.

Signed-off-by: Pavel Emelyanov <[email-masked]>

---

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 63f6917..6b9744f 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -274,19 +274,24 @@ 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_free:
+	free_netdev(dev);
 failed:
 	return NULL;
 }
diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c
index da28158..118e7d9 100644
--- a/net/ipv4/ipip.c
+++ b/net/ipv4/ipip.c
@@ -236,19 +236,24 @@ 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_free:
+	free_netdev(dev);
 failed:
 	return NULL;
 }
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index cd94064..fa83d70 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -245,17 +245,24 @@ 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;
 }
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index e77239d..a09a6b0 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -179,6 +179,11 @@ static struct ip_tunnel * ipip6_tunnel_locate(struct ip_tunnel_parm *parms, int
 	if (dev == NULL)
 		return NULL;
 
+	if (strchr(name, '%')) {
+		if (dev_alloc_name(dev, name) < 0)
+			goto failed_free;
+	}
+
 	nt = netdev_priv(dev);
 	dev->init = ipip6_tunnel_init;
 	nt->parms = *parms;
@@ -186,16 +191,16 @@ static struct ip_tunnel * ipip6_tunnel_locate(struct ip_tunnel_parm *parms, int
 	if (parms->i_flags & SIT_ISATAP)
 		dev->priv_flags |= IFF_ISATAP;
 
-	if (register_netdevice(dev) < 0) {
-		free_netdev(dev);
-		goto failed;
-	}
+	if (register_netdevice(dev) < 0)
+		goto failed_free;
 
 	dev_hold(dev);
 
 	ipip6_tunnel_link(nt);
 	return nt;
 
+failed_free:
+	free_netdev(dev);
 failed:
 	return NULL;
 }