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From: Pavel Emelyanov <xemul@openvz.org>
To: Andrew Morton <akpm@linux-foundation.org>,
	David Miller <davem@davemloft.net>
Cc: Alexey Dobriyan <adobriyan@openvz.org>,
	Linux Netdev List <netdev@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"Eric W. Biederman" <ebiederm@xmission.com>
Subject: [PATCH 0/2] Fix /proc/net in presence of net namespaces
Date: Thu, 28 Feb 2008 18:46:11 +0300	[thread overview]
Message-ID: <47C6D743.1050802@openvz.org> (raw)

Current /proc/net is done with so called "shadows", but current
implementation is broken and has little chances to get fixed.

The problem is that dentries subtree of /proc/net directory has
fancy revalidation rules to make processes living in different
net namespaces see different entries in /proc/net subtree, but
currently, tasks see in the /proc/net subdir the contents of any
other namespace, depending on who opened the file first.

The proposed fix is to turn /proc/net into a symlink, which behaves
similar to /proc/self link - it points to .netns/<id> directory 
where the <id> is the id of net namespace, current task lives in.

# ls -l /proc/net
lrwxrwxrwx  1 root root 8 Feb 28 18:38 /proc/net -> .netns/0

The /proc/.netns dir contains subtrees for all the namespaces in 
the system:

# ls -l /proc/.netns/
total 0
dr-xr-xr-x  5 root root 0 Feb 28 18:39 0
dr-xr-xr-x  3 root root 0 Feb 28 18:39 1

To provide some security each /proc/.netns/<id> directory allows
access to tasks that live in the owning namespace only (with the
exception, that init_net tasks can see everything).

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>

             reply	other threads:[~2008-02-28 15:47 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-28 15:46 Pavel Emelyanov [this message]
2008-02-28 15:49 ` [PATCH 1/2] Add an id to struct net Pavel Emelyanov
2008-02-28 15:51 ` [PATCH 2/2] Make /proc/net a symlink and drop proc shadows Pavel Emelyanov
2008-02-28 19:31 ` [PATCH 0/2] Fix /proc/net in presence of net namespaces Eric W. Biederman
2008-02-28 21:17   ` serge
2008-02-28 22:39     ` Eric W. Biederman
2008-02-29  3:17       ` serge
2008-02-29  8:16         ` Pavel Emelyanov
2008-02-29 15:38           ` serge
2008-02-29  7:58       ` Pavel Emelyanov
2008-03-02  2:03         ` Eric W. Biederman
2008-03-02  2:17         ` Eric W. Biederman
2008-03-03  9:07           ` Pavel Emelyanov
2008-03-04 22:49             ` Eric W. Biederman
2008-03-05  9:43               ` Pavel Emelyanov
2008-02-29  7:44     ` Pavel Emelyanov
2008-02-29  7:42   ` Pavel Emelyanov
2008-03-02  2:29     ` Eric W. Biederman
2008-03-03  8:52       ` Pavel Emelyanov
2008-03-04 22:23         ` Eric W. Biederman

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