Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757999AbXJCU5W (ORCPT ); Wed, 3 Oct 2007 16:57:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752441AbXJCU5K (ORCPT ); Wed, 3 Oct 2007 16:57:10 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:49459 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752415AbXJCU5I (ORCPT ); Wed, 3 Oct 2007 16:57:08 -0400 Date: Wed, 3 Oct 2007 21:57:03 +0100 From: Al Viro To: Casey Schaufler Cc: torvalds@osdl.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, akpm@osdl.org, paul.moore@hp.com Subject: Re: [PATCH] Version 4 (2.6.23-rc8-mm2) Smack: Simplified Mandatory Access Control Kernel Message-ID: <20071003205703.GM8181@ftp.linux.org.uk> References: <20071003175237.GK8181@ftp.linux.org.uk> <975177.66265.qm@web36601.mail.mud.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <975177.66265.qm@web36601.mail.mud.yahoo.com> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2253 Lines: 48 On Wed, Oct 03, 2007 at 12:51:08PM -0700, Casey Schaufler wrote: > > > Because you throw "simple" out the window when you require userland > > > assistance to perform this function. > > > > Any more than having /tmp replaced with a symlink? > > Yes. By the way, there's nothing that really requires that you > use a /smack symlink if you don't want to. /tmp can still be a > real directory, a mount point, a symlink to /var/tmp, or whatever > else you want it to be if that suits your needs better. For the > simplest scenarios /tmp -> /smack/tmp -> /moldy/ has every > other scheme I've seen throughly beaten. And your point is? If you don't use it, you get exact same complexity in both setups. > > _What_ userland intervention? Mounting stuff under /smack/tmp and not under > > your /moldy? > > Who said anything about mounting under /moldy? I never did. Sigh... So put the binding into fstab and be done with that. > > Having /tmp replaced with symlink to /smack/tmp.link instead > > of replacing it with a symlink to /smack/tmp? > > > > Absolute paths in that kind of thing are _wrong_. You know where the things > > are on your fs. You don't know if anything else will be visible, let alone > > whether it will be at the same place in all chroots or namespaces. And no, > > you _can't_ make sure that fs is visible only in one place. No fs can or > > has any business even trying. > > Is the objection that there is a default value coded in? Right now the main objection is about your lack of ability to read. Which part of "it can be mounted in different chroots/namespaces, therefore having absolute paths doesn't work" is too hard to understand? No, it's not about having a default. It's about keeping an absolute pathname in virtual fs, having all instances autosoddingmatically sharing it _and_ having change attempt in any instance automatically affect all of them. If you have that kind of sharing, don't pretend that your mechanism really allows absolute pathnames. - 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/