Commit 576b7cd2 authored Apr 03, 2015 by Nicolas Dichtel Committed by David S. Miller Apr 03, 2015

netns: don't allocate an id for dead netns



First, let's explain the problem.
Suppose you have an ipip interface that stands in the netns foo and its link
part in the netns bar (so the netns bar has an nsid into the netns foo).
Now, you remove the netns bar:
 - the bar nsid into the netns foo is removed
 - the netns exit method of ipip is called, thus our ipip iface is removed:
   => a netlink message is built in the netns foo to advertise this deletion
   => this netlink message requests an nsid for bar, thus a new nsid is
      allocated for bar and never removed.

This patch adds a check in peernet2id() so that an id cannot be allocated for
a netns which is currently destroyed.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 6d458f5b

net/core/net_namespace.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -198,8 +198,10 @@ static int __peernet2id(struct net net, struct net peer, bool alloc)
		*/
		int peernet2id(struct net net, struct net peer)
		{
		int id = __peernet2id(net, peer, true);
		bool alloc = atomic_read(&peer->count) == 0 ? false : true;
		int id;

		id = __peernet2id(net, peer, alloc);
		return id >= 0 ? id : NETNSA_NSID_NOT_ASSIGNED;
		}
		EXPORT_SYMBOL(peernet2id);

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