tun: call dev_get_valid_name() before register_netdevice()

register_netdevice() could fail early when we have an invalid
dev name, in which case ->ndo_uninit() is not called. For tun
device, this is a problem because a timer etc. are already
initialized and it expects ->ndo_uninit() to clean them up.

We could move these initializations into a ->ndo_init() so
that register_netdevice() knows better, however this is still
complicated due to the logic in tun_detach().

Therefore, I choose to just call dev_get_valid_name() before
register_netdevice(), which is quicker and much easier to audit.
And for this specific case, it is already enough.

Fixes: 96442e42429e ("tuntap: choose the txq based on rxq")
Reported-by: Dmitry Alexeev <avekceeb@gmail.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 5ce580f413b93f01cdfb80ab8c3d90fec0ad897d..e21bf90b819f8f77e4886a6d1ff7c7b5ca12bad0 100644 (file)
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -2027,6 +2027,9 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 
                if (!dev)
                        return -ENOMEM;
+               err = dev_get_valid_name(net, dev, name);
+               if (err)
+                       goto err_free_dev;
 
                dev_net_set(dev, net);
                dev->rtnl_link_ops = &tun_link_ops;

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index f535779d9dc1dfe36934c2abba4e43d053ac5d6f..2eaac7d75af4f1bbdaf876acc55b4bd0d37a7f36 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3694,6 +3694,9 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
                                    unsigned char name_assign_type,
                                    void (*setup)(struct net_device *),
                                    unsigned int txqs, unsigned int rxqs);
+int dev_get_valid_name(struct net *net, struct net_device *dev,
+                      const char *name);
+
 #define alloc_netdev(sizeof_priv, name, name_assign_type, setup) \
        alloc_netdev_mqs(sizeof_priv, name, name_assign_type, setup, 1, 1)
 

diff --git a/net/core/dev.c b/net/core/dev.c
index 588b473194a8a8ce23bde368b2b0350a3317db8b..11596a302a265212cb5dfe40f51b5b01fb20d0ce 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1147,9 +1147,8 @@ static int dev_alloc_name_ns(struct net *net,
        return ret;
 }
 
-static int dev_get_valid_name(struct net *net,
-                             struct net_device *dev,
-                             const char *name)
+int dev_get_valid_name(struct net *net, struct net_device *dev,
+                      const char *name)
 {
        BUG_ON(!net);
 
@@ -1165,6 +1164,7 @@ static int dev_get_valid_name(struct net *net,
 
        return 0;
 }
+EXPORT_SYMBOL(dev_get_valid_name);
 
 /**
  *     dev_change_name - change name of a device