From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 12 May 2002 12:42:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 12 May 2002 12:42:05 -0400 Received: from unthought.net ([212.97.129.24]:32151 "HELO mail.unthought.net") by vger.kernel.org with SMTP id ; Sun, 12 May 2002 12:42:05 -0400 Date: Sun, 12 May 2002 18:42:04 +0200 From: =?iso-8859-1?Q?Jakob_=D8stergaard?= To: Kasper Dupont Cc: Linux-Kernel Subject: Re: [RFC] ext2 and ext3 block reservations can be bypassed Message-ID: <20020512184204.A17334@unthought.net> Mail-Followup-To: =?iso-8859-1?Q?Jakob_=D8stergaard?= , Kasper Dupont , Linux-Kernel In-Reply-To: <3CDE96F9.8443C446@daimi.au.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit User-Agent: Mutt/1.2i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, May 12, 2002 at 06:23:21PM +0200, Kasper Dupont wrote: > Usually the last 5% of the diskspace on ext2 and ext3 > filesystems are reserved for root. But I just realized > that they can be bypassed by redirecting the output > from a suid root program to a file. > > This command will keep writing beyond the 95% limit: > while true ; do mount ; done >filename Hej Kasper, Sure you were not running the shell as root ? :) The redirection is handled by your shell, mount doesn't have anything to do with the '>filename' part. Actually, the more fun test is to mount > /etc/passwd or mount > /dev/hda But this won't work either, unless your shell (and therefore you as a user, suid programs or not) have the permissions as required. In short: I don't think you are seeing what you think you are seeing ;) -- ................................................................ : jakob@unthought.net : And I see the elder races, : :.........................: putrid forms of man : : Jakob Østergaard : See him rise and claim the earth, : : OZ9ABN : his downfall is at hand. : :.........................:............{Konkhra}...............: