From: Jamie Lokier <jamie@shareable.org>
To: Bodo Eggert <7eggert@gmx.de>
Cc: Miklos Szeredi <miklos@szeredi.hu>,
ericvh@gmail.com, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, smfrench@austin.rr.com,
hch@infradead.org
Subject: Re: [RCF] [PATCH] unprivileged mount/umount
Date: Wed, 11 May 2005 22:23:43 +0100 [thread overview]
Message-ID: <20050511212343.GC5093@mail.shareable.org> (raw)
In-Reply-To: <Pine.LNX.4.58.0505112121190.11888@be1.lrz>
Bodo Eggert wrote:
> > > > How about a new clone option "CLONE_NOSUID"?
> > >
> > > IMO, the clone call ist the wrong place to create namespaces. It
> > > should be deprecated by a mkdir/chdir-like interface.
> >
> > And the mkdir/chdir interface already exists, see "cd /proc/NNN/root".
>
> If you want persistent namespaces, this will be a PITA (I don't want a
> keep-the-namespace-open-daemon), and if you don't, it will be racy
> (user a logs in, while his second/nth login expires).
>
> Keeping a list of named namespaces in kernel can be made cheap and secure.
Still easy.
To keep persistent named namespaces in /var/namespaces, thus:
# Just once please!
mount -t tmpfs none /var/namespaces
# Make a named namespace.
NSNAME='fred'
mkdir /var/namespaces/$NSNAME
run_in_new_namespace mount -t bind / /var/namespaces/$NSNAME
# Make a named namespace for the _original_ namespace.
mkdir /var/namespaces/initial
mount -t bind / /var/namespaces/initial
# Access the namespace.
ls /var/namespaces/fred
# Enter the namespace.
chroot /var/namespaces/fred
# Delete a named namespace.
NSNAME='fred'
umount /var/namespaces/$NSNAME
rmdir /var/namespaces/$NSNAME
Some of the above will fail due to security checks in fs/namespace.c,
where it tests against current->namespace. Without those checks,
which seem to have no purpose _other_ than preventing the above usage,
I think the above would all work.
-- Jamie
next prev parent reply other threads:[~2005-05-11 21:24 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <406SQ-5P9-5@gated-at.bofh.it>
[not found] ` <40rNB-6p8-3@gated-at.bofh.it>
[not found] ` <40t37-7ol-5@gated-at.bofh.it>
[not found] ` <42VeB-8hG-3@gated-at.bofh.it>
[not found] ` <42WNo-1eJ-17@gated-at.bofh.it>
2005-05-11 16:41 ` [RCF] [PATCH] unprivileged mount/umount Bodo Eggert <harvested.in.lkml@posting.7eggert.dyndns.org>
2005-05-11 17:07 ` Jamie Lokier
2005-05-11 18:49 ` Miklos Szeredi
2005-05-11 19:05 ` serue
2005-05-11 19:46 ` Bodo Eggert
2005-05-11 20:40 ` Miklos Szeredi
2005-05-11 21:11 ` Jamie Lokier
2005-05-12 3:05 ` serue
2005-05-11 19:35 ` Ram
2005-05-11 20:31 ` Miklos Szeredi
2005-05-11 21:28 ` Jamie Lokier
2005-05-11 22:42 ` Ram
2005-05-11 22:58 ` Eric Van Hensbergen
2005-05-12 1:02 ` Jamie Lokier
2005-05-12 2:18 ` Eric Van Hensbergen
2005-05-12 6:45 ` Jamie Lokier
2005-05-12 13:23 ` Eric Van Hensbergen
2005-05-12 13:47 ` serue
2005-05-12 15:16 ` Jamie Lokier
2005-05-12 12:51 ` serue
2005-05-12 18:51 ` Miklos Szeredi
2005-05-12 19:56 ` Jamie Lokier
2005-05-13 8:55 ` Miklos Szeredi
2005-05-13 1:10 ` Ram
2005-05-13 6:06 ` Miklos Szeredi
2005-05-13 7:25 ` Ram
2005-05-13 8:59 ` Ram
2005-05-13 9:10 ` Miklos Szeredi
2005-05-13 16:53 ` Ram
2005-05-13 17:14 ` Miklos Szeredi
2005-05-13 18:44 ` Alan Cox
2005-05-13 20:56 ` Bryan Henderson
2005-05-12 0:59 ` Jamie Lokier
2005-05-13 6:41 ` Ram
2005-05-11 21:09 ` Jamie Lokier
2005-05-11 21:20 ` Miklos Szeredi
2005-05-11 21:32 ` Jamie Lokier
2005-05-11 19:32 ` Bodo Eggert
2005-05-11 21:23 ` Jamie Lokier [this message]
2005-05-11 21:34 ` Miklos Szeredi
2005-05-11 21:36 ` Jamie Lokier
2005-05-12 3:08 ` serue
2005-05-03 14:31 Miklos Szeredi
2005-05-03 17:30 ` Bill Davidsen
2005-05-04 13:08 ` Eric Van Hensbergen
2005-05-04 14:21 ` Miklos Szeredi
2005-05-04 14:51 ` Eric Van Hensbergen
2005-05-04 15:21 ` Miklos Szeredi
2005-05-11 8:51 ` Christoph Hellwig
2005-05-11 10:31 ` Miklos Szeredi
2005-05-12 21:08 ` Bryan Henderson
2005-05-13 5:47 ` Miklos Szeredi
2005-05-13 7:19 ` Jan Hudec
2005-05-13 8:33 ` Miklos Szeredi
2005-05-13 23:09 ` Bryan Henderson
2005-05-14 6:58 ` Miklos Szeredi
2005-05-16 18:35 ` Bryan Henderson
2005-05-14 11:49 ` Jamie Lokier
2005-05-04 13:47 ` Martin Waitz
2005-05-04 14:34 ` Miklos Szeredi
2005-05-11 8:53 ` Christoph Hellwig
2005-05-11 8:48 ` Christoph Hellwig
2005-05-11 10:20 ` Miklos Szeredi
2005-05-16 9:34 ` Christoph Hellwig
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