net: fix creation adjacent device symlinks

__netdev_adjacent_dev_insert may add adjust device of different net
namespace, without proper check it leads to emergence of broken
sysfs links from/to devices in another namespace.
Fix: rewrite netdev_adjacent_is_neigh_list macro as a function,
     move net_eq check into netdev_adjacent_is_neigh_list.
     (thanks David)
     related to: 4c75431ac3520631f1d9e74aa88407e6374dbbc4

Signed-off-by: Alexander Fomichev <git.user@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/dev.c b/net/core/dev.c
index ab9a165..cf8a95f 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4809,9 +4809,14 @@ static void netdev_adjacent_sysfs_del(struct net_device *dev,
        sysfs_remove_link(&(dev->dev.kobj), linkname);
 }
 
-#define netdev_adjacent_is_neigh_list(dev, dev_list) \
-               (dev_list == &dev->adj_list.upper || \
-                dev_list == &dev->adj_list.lower)
+static inline bool netdev_adjacent_is_neigh_list(struct net_device *dev,
+                                                struct net_device *adj_dev,
+                                                struct list_head *dev_list)
+{
+       return (dev_list == &dev->adj_list.upper ||
+               dev_list == &dev->adj_list.lower) &&
+               net_eq(dev_net(dev), dev_net(adj_dev));
+}
 
 static int __netdev_adjacent_dev_insert(struct net_device *dev,
                                        struct net_device *adj_dev,
@@ -4841,7 +4846,7 @@ static int __netdev_adjacent_dev_insert(struct net_device *dev,
        pr_debug("dev_hold for %s, because of link added from %s to %s\n",
                 adj_dev->name, dev->name, adj_dev->name);
 
-       if (netdev_adjacent_is_neigh_list(dev, dev_list)) {
+       if (netdev_adjacent_is_neigh_list(dev, adj_dev, dev_list)) {
                ret = netdev_adjacent_sysfs_add(dev, adj_dev, dev_list);
                if (ret)
                        goto free_adj;
@@ -4862,7 +4867,7 @@ static int __netdev_adjacent_dev_insert(struct net_device *dev,
        return 0;
 
 remove_symlinks:
-       if (netdev_adjacent_is_neigh_list(dev, dev_list))
+       if (netdev_adjacent_is_neigh_list(dev, adj_dev, dev_list))
                netdev_adjacent_sysfs_del(dev, adj_dev->name, dev_list);
 free_adj:
        kfree(adj);
@@ -4895,8 +4900,7 @@ 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) &&
-           net_eq(dev_net(dev),dev_net(adj_dev)))
+       if (netdev_adjacent_is_neigh_list(dev, adj_dev, dev_list))
                netdev_adjacent_sysfs_del(dev, adj_dev->name, dev_list);
 
        list_del_rcu(&adj->list);