linux-kernel - Re: sys_chroot+sys

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Date:	Wed, 19 Sep 2007 14:27:22 -0400
From:	Bill Davidsen <davidsen@....com>
To:	Alan Cox <alan@...rguk.ukuu.org.uk>
CC:	majkls <majkls@...pere.com>, bunk@...tum.de,
	linux-kernel@...r.kernel.org
Subject: Re: sys_chroot+sys_fchdir Fix

Alan Cox wrote:
> On Wed, 19 Sep 2007 09:19:50 +0200
> majkls <majkls@...pere.com> wrote:
> 
>> Hello,
>> here is an fix to an exploit (obtained somewhere in internet). This 
>> exploit can workaround chroot with CAP_SYS_CHROOT. It is also possible 
>> (with sufficient filedescriptor (if there is na directory fd opened in 
>> root) workaround chroot with sys_fchdir. This patch fixes it.
> 
> 
> If you have the ability to use chroot() you are root. If you are root you
> can walk happily out of any chroot by a thousand other means.
> 
I thought this was to prevent breaking out of chroot as a normal user.
	ie. chroot /var/myjail /bin/su - guest
or similar.

-- 
Bill Davidsen <davidsen@....com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot
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