net: feed /dev/random with the MAC address when registering a device

Cc: David Miller <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org

net/core/dev.c

@@ -1172,6 +1172,7 @@ static int __dev_open(struct net_device *dev)
 		net_dmaengine_get();
 		dev_set_rx_mode(dev);
 		dev_activate(dev);
+		add_device_randomness(dev->dev_addr, dev->addr_len);
 	}
 
 	return ret;
@@ -4763,6 +4764,7 @@ int dev_set_mac_address(struct net_device *dev, struct sockaddr *sa)
 	err = ops->ndo_set_mac_address(dev, sa);
 	if (!err)
 		call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
+	add_device_randomness(dev->dev_addr, dev->addr_len);
 	return err;
 }
 EXPORT_SYMBOL(dev_set_mac_address);
@@ -5541,6 +5543,7 @@ int register_netdevice(struct net_device *dev)
 	dev_init_scheduler(dev);
 	dev_hold(dev);
 	list_netdevice(dev);
+	add_device_randomness(dev->dev_addr, dev->addr_len);
 
 	/* Notify protocols, that a new device appeared. */
 	ret = call_netdevice_notifiers(NETDEV_REGISTER, dev);

net/core/rtnetlink.c

@@ -1378,6 +1378,7 @@ static int do_setlink(struct net_device *dev, struct ifinfomsg *ifm,
 			goto errout;
 		send_addr_notify = 1;
 		modified = 1;
+		add_device_randomness(dev->dev_addr, dev->addr_len);
 	}
 
 	if (tb[IFLA_MTU]) {