Skip site navigation (1)Skip section navigation (2)
Date:      Sat, 23 Sep 2006 14:39:02 +0200
From:      Jeremie Le Hen <jeremie@le-hen.org>
To:        freebsd-questions@FreeBSD.org
Cc:        jeremie@le-hen.org
Subject:   Re: [fbsd] chrooted named in a jail
Message-ID:  <20060923123902.GV15761@obiwan.tataz.chchile.org>
In-Reply-To: <20060921193110.GL15761@obiwan.tataz.chchile.org>
References:  <20060921193110.GL15761@obiwan.tataz.chchile.org>

next in thread | previous in thread | raw e-mail | index | archive | help
Hi list,

On Thu, Sep 21, 2006 at 09:31:10PM +0200, Jeremie Le Hen wrote:
> Hi list,
> 
> please Cc: me in your replies, I am not subscribed to this list.
> 
> I have a jail in which named(8) runs.  In order to make a possible bug
> exploitation still more difficult, I would like to use the named_chrootdir
> variable for rc.conf(5).
> 
> Unfortunately, rc.d/named tries to mount devfs in the named_chrootdir,
> which is obviously not possible inside a jail.  I could hack the jail
> startup bit in order to mount devfs in $jaildir/$named_chrootdir/dev,
> but I find this a bit overkill and I am looking for a neater way to
> achieve this.  I thought of using $jail_fstab and $jail_mount_enable
> in order to mount_nullfs(8) $jaildir/dev onto $jaildir/$named_chrootdir/dev
> but I am not sure this is allowed by the kernel (I'm scared to panic my
> production box).
> 
> Any clue, idea ?

For your information, I achieved to run a chrooted named(8) inside
a jail with two small patches I submitted in the following PRs:

http://www.freebsd.org/cgi/query-pr.cgi?pr=103486
http://www.freebsd.org/cgi/query-pr.cgi?pr=103489

The second PR prevents rc.d/named from doing devfs stuff inside a
jail, using the security.jail.jailed sysctl.

The first PR makes rc.d/jail mount jail's devfs before jail's fstab.
This way, I can use /etc/fstab.<jname> to null-mount $jail_rootdir/dev
onto $jail_rootdir/$named_chrootdir/dev.

Regards,
-- 
Jeremie Le Hen
< jeremie at le-hen dot org >< ttz at chchile dot org >



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20060923123902.GV15761>