From: Miloslav Semler <majkls@prepere.com>
To: Jan Engelhardt <jengelh@computergmbh.de>
Cc: serge@hallyn.com, davidsen@tmr.com, philipp@marek.priv.at,
7eggert@gmx.de, alan@lxorguk.ukuu.org.uk, bunk@fs.tum.de,
linux-kernel@vger.kernel.org
Subject: Re: Chroot bug
Date: Tue, 25 Sep 2007 17:39:19 +0200 [thread overview]
Message-ID: <46F92BA7.8030304@prepere.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0709251715390.945@fbirervta.pbzchgretzou.qr>
> On Sep 26 2007 00:40, David Newall wrote:
>
>> Miloslav Semler pointed out that a root process can chdir("..") out of its
>> chroot. Although this is documented in the man page, it conflicts with the
>> essential function, which is to change the root directory of the process. In
>> addition to any creative uses, for example Philipp Marek's loading dynamic
>> libraries, it seems clear that the prime purpose of chroot is to aid security.
>> Being able to cd your way out is handy for the bad guys, but the good guys
>> don't need it; there are a thousand better, safer solutions.
>>
>
> So what? Just do this: chdir into the root after chroot.
>
> It won't conform to SVR4/4.4BSD anymore, but hey, let Linux set some
> sane standard ain't bad either. I doubt anyone really relies on the
> fact that after chroot, your cwd might be outside the root.
>
so then you corrupt pwd. I think that working directory should be set
only if it is necessary. Fn directory_is_out is not big performace loss.
And also you can break this fix with fchdir.
Miloslav
next prev parent reply other threads:[~2007-09-25 15:46 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <952DN-83o-31@gated-at.bofh.it>
[not found] ` <954cl-29C-3@gated-at.bofh.it>
[not found] ` <95ctn-74b-15@gated-at.bofh.it>
[not found] ` <95cMH-7um-19@gated-at.bofh.it>
[not found] ` <95gdA-4OZ-7@gated-at.bofh.it>
2007-09-20 11:13 ` sys_chroot+sys_fchdir Fix Bodo Eggert
2007-09-20 11:59 ` Philipp Marek
2007-09-20 12:52 ` majkls
2007-09-20 16:06 ` David Newall
2007-09-20 16:17 ` Philipp Marek
2007-09-20 18:02 ` David Newall
2007-09-20 20:53 ` Bill Davidsen
2007-09-21 8:29 ` David Newall
2007-09-24 21:32 ` Serge E. Hallyn
2007-09-24 22:04 ` David Newall
2007-09-24 23:00 ` Serge E. Hallyn
2007-09-25 7:45 ` David Newall
2007-09-25 11:49 ` Serge E. Hallyn
2007-09-25 13:58 ` David Newall
2007-09-25 15:10 ` Chroot bug (was: sys_chroot+sys_fchdir Fix) David Newall
2007-09-25 15:20 ` Jan Engelhardt
2007-09-25 15:39 ` Miloslav Semler [this message]
2007-09-25 15:41 ` Chroot bug David Newall
2007-09-25 15:48 ` Jan Engelhardt
2007-09-25 16:19 ` Miloslav Semler
2007-09-25 16:52 ` Jan Engelhardt
2007-09-25 17:00 ` Miloslav Semler
2007-09-25 17:05 ` Jan Engelhardt
2007-09-25 17:09 ` Miloslav Semler
2007-09-25 17:09 ` Al Viro
2007-09-25 17:19 ` Miloslav Semler
2007-09-25 16:53 ` Serge E. Hallyn
2007-09-25 20:51 ` David Newall
2007-09-25 15:30 ` Chroot bug (was: sys_chroot+sys_fchdir Fix) Alan Cox
2007-09-25 15:35 ` Chroot bug David Newall
2007-09-25 15:48 ` Alan Cox
2007-09-25 15:47 ` Jan Engelhardt
2007-09-25 23:50 ` David Newall
2007-09-26 0:18 ` Alan Cox
2007-09-26 10:24 ` David Newall
2007-09-26 10:47 ` Alan Cox
2007-09-26 11:06 ` David Newall
2007-09-26 11:20 ` Alan Cox
[not found] ` <46FA41B4.9040104@prepere.com>
[not found] ` <20070926123522.54ffd56f@the-village.bc.nu>
2007-09-26 11:34 ` Miloslav Semler
2007-09-26 14:09 ` Alan Cox
2007-09-26 13:13 ` Bongani Hlope
2007-09-26 0:55 ` Adrian Bunk
2007-09-26 5:21 ` Kyle Moffett
2007-09-26 5:25 ` Willy Tarreau
2007-09-26 10:27 ` David Newall
2007-09-26 10:45 ` Olivier Galibert
2007-09-26 11:13 ` David Newall
2007-09-26 13:18 ` linux-os (Dick Johnson)
2007-09-26 15:02 ` Olivier Galibert
2007-09-26 12:54 ` Kyle Moffett
2007-09-26 13:11 ` Miloslav Semler
2007-09-26 13:42 ` Al Viro
2007-09-26 14:51 ` Miloslav Semler
2007-09-26 14:02 ` Kyle Moffett
2007-09-26 15:01 ` Miloslav Semler
2007-09-27 13:49 ` Jiri Kosina
2007-09-25 16:33 ` Arjan van de Ven
2007-09-25 15:32 ` Chroot bug (was: sys_chroot+sys_fchdir Fix) Adrian Bunk
2007-09-25 15:43 ` Chroot bug Miloslav Semler
2007-09-25 16:02 ` Adrian Bunk
2007-09-26 19:23 ` Chroot bug (was: sys_chroot+sys_fchdir Fix) Bodo Eggert
2007-09-24 23:02 ` sys_chroot+sys_fchdir Fix Serge E. Hallyn
[not found] ` <95UE2-1oR-19@gated-at.bofh.it>
[not found] ` <95V72-2ly-17@gated-at.bofh.it>
[not found] ` <97pG8-3B5-47@gated-at.bofh.it>
[not found] ` <97sX2-p1-3@gated-at.bofh.it>
2007-09-26 9:38 ` Nick Craig-Wood
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=46F92BA7.8030304@prepere.com \
--to=majkls@prepere.com \
--cc=7eggert@gmx.de \
--cc=alan@lxorguk.ukuu.org.uk \
--cc=bunk@fs.tum.de \
--cc=davidsen@tmr.com \
--cc=jengelh@computergmbh.de \
--cc=linux-kernel@vger.kernel.org \
--cc=philipp@marek.priv.at \
--cc=serge@hallyn.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.