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Commit 4c75431a authored by Alexander Y. Fomichev's avatar Alexander Y. Fomichev Committed by David S. Miller
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net: prevent of emerging cross-namespace symlinks 



Code manipulating sysfs symlinks on adjacent net_devices(s)
currently doesn't take into account that devices potentially
belong to different namespaces.

This patch trying to fix an issue as follows:
- check for net_ns before creating / deleting symlink.
  for now only netdev_adjacent_rename_links and
  __netdev_adjacent_dev_remove are affected, afaics
  __netdev_adjacent_dev_insert implies both net_devs
  belong to the same namespace.
- Drop all existing symlinks to / from all adj_devs before
  switching namespace and recreate them just after.

Signed-off-by: default avatarAlexander Y. Fomichev <git.user@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a45e92a5

net/core/dev.c

+60 −1
Original line number Diff line number Diff line
@@ -4889,7 +4889,8 @@ static void __netdev_adjacent_dev_remove(struct net_device *dev, 
	if (adj->master)

		sysfs_remove_link(&(dev->dev.kobj), "master");



	if (netdev_adjacent_is_neigh_list(dev, dev_list))

	if (netdev_adjacent_is_neigh_list(dev, dev_list) &&

	    net_eq(dev_net(dev),dev_net(adj_dev)))

		netdev_adjacent_sysfs_del(dev, adj_dev->name, dev_list);



	list_del_rcu(&adj->list);
@@ -5159,11 +5160,65 @@ void netdev_upper_dev_unlink(struct net_device *dev, 
}

EXPORT_SYMBOL(netdev_upper_dev_unlink);



void netdev_adjacent_add_links(struct net_device *dev)

{

	struct netdev_adjacent *iter;



	struct net *net = dev_net(dev);



	list_for_each_entry(iter, &dev->adj_list.upper, list) {

		if (!net_eq(net,dev_net(iter->dev)))

			continue;

		netdev_adjacent_sysfs_add(iter->dev, dev,

					  &iter->dev->adj_list.lower);

		netdev_adjacent_sysfs_add(dev, iter->dev,

					  &dev->adj_list.upper);

	}



	list_for_each_entry(iter, &dev->adj_list.lower, list) {

		if (!net_eq(net,dev_net(iter->dev)))

			continue;

		netdev_adjacent_sysfs_add(iter->dev, dev,

					  &iter->dev->adj_list.upper);

		netdev_adjacent_sysfs_add(dev, iter->dev,

					  &dev->adj_list.lower);

	}

}



void netdev_adjacent_del_links(struct net_device *dev)

{

	struct netdev_adjacent *iter;



	struct net *net = dev_net(dev);



	list_for_each_entry(iter, &dev->adj_list.upper, list) {

		if (!net_eq(net,dev_net(iter->dev)))

			continue;

		netdev_adjacent_sysfs_del(iter->dev, dev->name,

					  &iter->dev->adj_list.lower);

		netdev_adjacent_sysfs_del(dev, iter->dev->name,

					  &dev->adj_list.upper);

	}



	list_for_each_entry(iter, &dev->adj_list.lower, list) {

		if (!net_eq(net,dev_net(iter->dev)))

			continue;

		netdev_adjacent_sysfs_del(iter->dev, dev->name,

					  &iter->dev->adj_list.upper);

		netdev_adjacent_sysfs_del(dev, iter->dev->name,

					  &dev->adj_list.lower);

	}

}



void netdev_adjacent_rename_links(struct net_device *dev, char *oldname)

{

	struct netdev_adjacent *iter;



	struct net *net = dev_net(dev);



	list_for_each_entry(iter, &dev->adj_list.upper, list) {

		if (!net_eq(net,dev_net(iter->dev)))

			continue;

		netdev_adjacent_sysfs_del(iter->dev, oldname,

					  &iter->dev->adj_list.lower);

		netdev_adjacent_sysfs_add(iter->dev, dev,
@@ -5171,6 +5226,8 @@ void netdev_adjacent_rename_links(struct net_device *dev, char *oldname) 
	}



	list_for_each_entry(iter, &dev->adj_list.lower, list) {

		if (!net_eq(net,dev_net(iter->dev)))

			continue;

		netdev_adjacent_sysfs_del(iter->dev, oldname,

					  &iter->dev->adj_list.upper);

		netdev_adjacent_sysfs_add(iter->dev, dev,
@@ -6773,6 +6830,7 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char 


	/* Send a netdev-removed uevent to the old namespace */

	kobject_uevent(&dev->dev.kobj, KOBJ_REMOVE);

	netdev_adjacent_del_links(dev);



	/* Actually switch the network namespace */

	dev_net_set(dev, net);
@@ -6787,6 +6845,7 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char 


	/* Send a netdev-add uevent to the new namespace */

	kobject_uevent(&dev->dev.kobj, KOBJ_ADD);

	netdev_adjacent_add_links(dev);



	/* Fixup kobjects */

	err = device_rename(&dev->dev, dev->name);