Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760826AbXIYRJc (ORCPT ); Tue, 25 Sep 2007 13:09:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759875AbXIYRJQ (ORCPT ); Tue, 25 Sep 2007 13:09:16 -0400 Received: from h90-m1.hosting90.cz ([81.0.225.70]:38803 "EHLO h90-m1.hosting90.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759068AbXIYRJO (ORCPT ); Tue, 25 Sep 2007 13:09:14 -0400 Message-ID: <46F940B9.8060006@prepere.com> Date: Tue, 25 Sep 2007 19:09:13 +0200 From: Miloslav Semler User-Agent: IceDove 1.5.0.12 (X11/20070607) MIME-Version: 1.0 To: Jan Engelhardt CC: serge@hallyn.com, davidsen@tmr.com, philipp@marek.priv.at, 7eggert@gmx.de, alan@lxorguk.ukuu.org.uk, linux-kernel@vger.kernel.org Subject: Re: Chroot bug References: <56705.193.171.152.61.1190289559.squirrel@webmail.marek.priv.at> <46F29A9A.4070806@davidnewall.com> <200709201817.17282@x5> <46F2B59F.8090709@davidnewall.com> <46F2DDD0.3030500@tmr.com> <46F380E4.4040606@davidnewall.com> <20070924213215.GA32716@vino.hallyn.com> <46F83474.5040503@davidnewall.com> <20070924230008.GA3160@vino.hallyn.com> <46F8BC8A.7080006@davidnewall.com> <20070925114947.GA9721@vino.hallyn.com> <46F91417.9050600@davidnewall.com> <46F924E3.50205@davidnewall.com> <46F92C17.3060405@davidnewall.com> <46F9351D.8020906@prepere.com> <46F93EAF.20706@prepere.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1312 Lines: 39 Jan Engelhardt napsal(a): > On Sep 25 2007 19:00, Miloslav Semler wrote: > >>>> This does not help. Let's try: >>>> chroot somewhere >>>> mkdir foo >>>> fd = open / >>>> chroot foo >>>> >>>> >>> ('fd' implicitly closed and chdir to /foo) >>> >>> >> Really? Try it. I am sure, that this works. You can create directory in chroot >> and break chroot by this. fd is not closed, because linux doesn't close >> descriptors by chroot syscall. this can be done every time if you have >> CAP_SYS_CHROOT. >> > > In case you have not followed my earlier email, I'll repost: > > |>> So what? Just do this: chdir into the root after chroot. > |> > |> I don't think so. His exploit just got me all the way out of a > |> chroot within a chroot within a chroot, inclusive of lots of > |> chdirs. > |> > | > |Close all fds that point to directories outside the root ;-) > > Perhaps that was formulated a bit sloppy. It of course means > "On chroot(2), implicitly close all FDs that point outside." > yes, but I can use fds from chroot ;-) .... - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/