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Commit 638c8339 authored by Cong Wang's avatar Cong Wang Committed by Greg Kroah-Hartman
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tun: call dev_get_valid_name() before register_netdevice() 




[ Upstream commit 0ad646c81b2182f7fa67ec0c8c825e0ee165696d ]

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: 96442e42 ("tuntap: choose the txq based on rxq")
Reported-by: default avatarDmitry Alexeev <avekceeb@gmail.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Signed-off-by: default avatarCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a5bec3f1

drivers/net/tun.c

+3 −0
Original line number Diff line number Diff line
@@ -1656,6 +1656,9 @@ 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;

include/linux/netdevice.h

+3 −0
Original line number Diff line number Diff line
@@ -3245,6 +3245,9 @@ 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)

net/core/dev.c

+3 −3
Original line number Diff line number Diff line
@@ -1059,8 +1059,7 @@ static int dev_alloc_name_ns(struct net *net, 
	return ret;

}



static int dev_get_valid_name(struct net *net,

			      struct net_device *dev,

int dev_get_valid_name(struct net *net, struct net_device *dev,

		       const char *name)

{

	BUG_ON(!net);
@@ -1077,6 +1076,7 @@ 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