Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755345AbXL3Dob (ORCPT ); Sat, 29 Dec 2007 22:44:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753086AbXL3DoW (ORCPT ); Sat, 29 Dec 2007 22:44:22 -0500 Received: from turing-police.cc.vt.edu ([128.173.14.107]:37720 "EHLO turing-police.cc.vt.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752911AbXL3DoV (ORCPT ); Sat, 29 Dec 2007 22:44:21 -0500 X-Mailer: exmh version 2.7.2 01/07/2005 with nmh-1.2 To: dean gaudet Cc: David Newall , Mark Lord , Al Viro , Alexander Viro , Andrew Morton , Linux Kernel Subject: Re: RFC: permit link(2) to work across --bind mounts ? In-Reply-To: Your message of "Sat, 29 Dec 2007 12:40:47 PST." From: Valdis.Kletnieks@vt.edu References: <47684DBD.6030502@rtr.ca> <20071218230016.GF8181@ftp.linux.org.uk> <20071218231404.GG8181@ftp.linux.org.uk> <47689608.3030503@rtr.ca> <4768973C.8020909@davidnewall.com> <47760578.2090305@davidnewall.com> <4776AF82.6010808@davidnewall.com> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_1198986232_3779P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Date: Sat, 29 Dec 2007 22:43:52 -0500 Message-ID: <25388.1198986232@turing-police.cc.vt.edu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2122 Lines: 55 --==_Exmh_1198986232_3779P Content-Type: text/plain; charset=us-ascii On Sat, 29 Dec 2007 12:40:47 PST, dean gaudet said: > > See, this is where you show that you don't understand the system. I'll > > explain it, just once. /var/home contains home directories. /var/log and > > /var/home are on the same filesystem. So /var/log/* can be linked to > > /var/home/malicious, and that's just one of your basic misunderstandings. > > yes you are on crack. > > i told you i understand this exactly. it's right there in the message > sent. So... You understand that if /var/home and /var/log are on one file system, you can hard-link, and you set your system up knowing that, and then you're *surprised* that: > the main worry i have is some user maliciously hardlinks everything > under /var/log somewhere else and slowly fills up the file system with > old rotated logs. "Doctor, it hurts when I do this.." "Well, don't do that then". I think the first time I saw the recommendation "Put /home on its own filesystem and don't give users directly writable directories on /var (except via set-uid helpers) so they can't play hardlink games" back in 1983 or so. I know that when SunOS 3.1 came out, that was already well-understood basic sysadmining. Sometimes, there's actual good reasons behind 20-year-old voodoo.. ;) You sure you don't want to redesign your filesystem layout so you don't have to worry about your malicious users hardlinking stuff? Might be a lot easier than trying to get the kernel to do what you want in this case.... --==_Exmh_1198986232_3779P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.8 (GNU/Linux) Comment: Exmh version 2.5 07/13/2001 iD8DBQFHdxP4cC3lWbTT17ARAnI+AKDy+I+wnx4dqqy+xHmBEa501qjWtQCgsWt4 vyEFBWgrsadb6aXHQ8JQY30= =QkUe -----END PGP SIGNATURE----- --==_Exmh_1198986232_3779P-- -- 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/