vlan: fail early when creating netdev named config

Similarly, vlan will create  /proc/net/vlan/<dev>, so when we
create dev with name "config", it will confict with
/proc/net/vlan/config.

Reported-by: Stephane Chazelas <stephane.chazelas@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 15 insertions, 8 deletions

diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
index cba9c212a730..64c6bed4a3d3 100644
--- a/net/8021q/vlan.c
+++ b/net/8021q/vlan.c
@@ -325,23 +325,24 @@ static void vlan_transfer_features(struct net_device *dev,
         netdev_update_features(vlandev);
 }
 
-static void __vlan_device_event(struct net_device *dev, unsigned long event)
+static int __vlan_device_event(struct net_device *dev, unsigned long event)
 {
+        int err = 0;
+
         switch (event) {
         case NETDEV_CHANGENAME:
                 vlan_proc_rem_dev(dev);
-                if (vlan_proc_add_dev(dev) < 0)
-                        pr_warn("failed to change proc name for %s\n",
-                                dev->name);
+                err = vlan_proc_add_dev(dev);
                 break;
         case NETDEV_REGISTER:
-                if (vlan_proc_add_dev(dev) < 0)
-                        pr_warn("failed to add proc entry for %s\n", dev->name);
+                err = vlan_proc_add_dev(dev);
                 break;
         case NETDEV_UNREGISTER:
                 vlan_proc_rem_dev(dev);
                 break;
         }
+
+        return err;
 }
 
 static int vlan_device_event(struct notifier_block *unused, unsigned long event,
@@ -356,8 +357,12 @@ static int vlan_device_event(struct notifier_block *unused, unsigned long event,
         bool last = false;
         LIST_HEAD(list);
 
-        if (is_vlan_dev(dev))
-                __vlan_device_event(dev, event);
+        if (is_vlan_dev(dev)) {
+                int err = __vlan_device_event(dev, event);
+
+                if (err)
+                        return notifier_from_errno(err);
+        }
 
         if ((event == NETDEV_UP) &&
             (dev->features & NETIF_F_HW_VLAN_CTAG_FILTER)) {
diff --git a/net/8021q/vlanproc.c b/net/8021q/vlanproc.c
index 1d0e89213a28..ae63cf72a953 100644
--- a/net/8021q/vlanproc.c
+++ b/net/8021q/vlanproc.c
@@ -171,6 +171,8 @@ int vlan_proc_add_dev(struct net_device *vlandev)
         struct vlan_dev_priv *vlan = vlan_dev_priv(vlandev);
         struct vlan_net *vn = net_generic(dev_net(vlandev), vlan_net_id);
 
+        if (!strcmp(vlandev->name, name_conf))
+                return -EINVAL;
         vlan->dent =
                 proc_create_data(vlandev->name, S_IFREG|S_IRUSR|S_IWUSR,
                                  vn->proc_vlan_dir, &vlandev_fops, vlandev);