Re: [PATCH net 0/2] netns: audit netdevice creation with IFLA_NET_NS_[PID|FD]

[Alexander Aring <alex.aring@gmail.com>]

On Tue, Jan 27, 2015 at 01:23:40PM +0100, Alexander Aring wrote:
...
> Summarize:
> 
> I would add the dev->features |= NETIF_F_NETNS_LOCAL; while wpan
> interface generation and add only the !net_eq(src_net, &init_net) check
> above. I suppose that src_net is the net namespace from "underlaying"
> interface wpan by calling:
> 
> $ ip link add link wpan0 name lowpan0 type lowpan
> 

should look something like:

diff --git a/net/ieee802154/6lowpan/core.c b/net/ieee802154/6lowpan/core.c
index 055fbb7..a44963c 100644
--- a/net/ieee802154/6lowpan/core.c
+++ b/net/ieee802154/6lowpan/core.c
@@ -148,10 +148,11 @@ static int lowpan_newlink(struct net *src_net, struct net_device *dev,
 
        pr_debug("adding new link\n");
 
-       if (!tb[IFLA_LINK])
+       if (!tb[IFLA_LINK] |
+           !net_eq(src_net, &init_net))
                return -EINVAL;
        /* find and hold real wpan device */
-       real_dev = dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
+       real_dev = dev_get_by_index(&init_net, nla_get_u32(tb[IFLA_LINK]));
        if (!real_dev)
                return -ENODEV;
        if (real_dev->type != ARPHRD_IEEE802154) {
diff --git a/net/ieee802154/core.c b/net/ieee802154/core.c
index 18bc7e7..161f0e5 100644
--- a/net/ieee802154/core.c
+++ b/net/ieee802154/core.c
@@ -229,6 +229,8 @@ static int cfg802154_netdev_notifier_call(struct notifier_block *nb,
                list_add_rcu(&wpan_dev->list, &rdev->wpan_dev_list);
                rdev->devlist_generation++;
 
+               /* can only change netns with wpan_phy */
+               dev->features |= NETIF_F_NETNS_LOCAL;
                wpan_dev->netdev = dev;
                break;
        case NETDEV_DOWN:
--


In ieee802154/core.c we set (like wireless it also does) the
dev->features |= NETIF_F_NETNS_LOCAL; for wpan interface.


In net/ieee802154/6lowpan/core.c, we only check if the wpan interface
belongs to !net_eq(src_net, &init_net).


On 6LoWPAN 802.15.4 interfaces it should be still possible to change
the net namespace.

- Alex