Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755837AbXJCFNP (ORCPT ); Wed, 3 Oct 2007 01:13:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751438AbXJCFNA (ORCPT ); Wed, 3 Oct 2007 01:13:00 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:34753 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751046AbXJCFM7 (ORCPT ); Wed, 3 Oct 2007 01:12:59 -0400 Date: Wed, 3 Oct 2007 06:12:54 +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: <20071003051254.GH8181@ftp.linux.org.uk> References: <47031E76.6020801@schaufler-ca.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <47031E76.6020801@schaufler-ca.com> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1884 Lines: 37 On Tue, Oct 02, 2007 at 09:45:42PM -0700, Casey Schaufler wrote: > > From: Casey Schaufler > > Smack is the Simplified Mandatory Access Control Kernel. > > Smack implements mandatory access control (MAC) using labels > attached to tasks and data containers, including files, SVIPC, > and other tasks. Smack is a kernel based scheme that requires > an absolute minimum of application support and a very small > amount of configuration data. I _really_ don't like what you are doing with these symlinks. For one thing, you have no exclusion between reading the list entries and modifying them. For another... WTF is filesystem making assumptions about the locations where the things are mounted? Hell, even if you override your tmp symlink, what happens if we want it in two chroot jails with different layouts? I really don't get it; why not simply have something like /smack/tmp.link resolve to tmp/ and have userland bind or mount whatever you bloody like on /smack/tmp? No problems with absolute paths, can be used in chroot jails with whatever layouts, ditto for namespaces, etc. and both symlink and directory get created at the same time (by one name). Hell, if you keep a reference to dentry of directory in the data associated with symlink, you can simply switch nd->dentry to that, drop the old one and grab the reference to page containing label and return it via nd_set_link(). No need to play with allocations, strcat, yadda, yadda. readlink() can stuff the ->d_name of the same dentry plus / plus label directly into user buffer; again, no allocations needed and works fine anywhere. - 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/