Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030641AbWKOQTI (ORCPT ); Wed, 15 Nov 2006 11:19:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030632AbWKOQTH (ORCPT ); Wed, 15 Nov 2006 11:19:07 -0500 Received: from mail1.sea5.speakeasy.net ([69.17.117.3]:41124 "EHLO mail1.sea5.speakeasy.net") by vger.kernel.org with ESMTP id S1030641AbWKOQTE (ORCPT ); Wed, 15 Nov 2006 11:19:04 -0500 Date: Wed, 15 Nov 2006 11:19:00 -0500 (EST) From: James Morris X-X-Sender: jmorris@d.namei To: David Howells cc: Linus Torvalds , Andrew Morton , Stephen Smalley , trond.myklebust@fys.uio.no, selinux@tycho.nsa.gov, linux-kernel@vger.kernel.org, aviro@redhat.com, steved@redhat.com Subject: Re: [PATCH 12/19] CacheFiles: Permit a process's create SID to be overridden In-Reply-To: <15153.1163593562@redhat.com> Message-ID: References: <20061114200621.12943.18023.stgit@warthog.cambridge.redhat.com> <20061114200647.12943.39802.stgit@warthog.cambridge.redhat.com> <15153.1163593562@redhat.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1275 Lines: 37 On Wed, 15 Nov 2006, David Howells wrote: > James Morris wrote: > > > > +static u32 selinux_set_fscreate_secid(u32 secid) > > ... > > The ability to set this needs to be mediated via MAC policy. > > There could a problem with that... Is it possible for there to be a race? Well, the value can be changed at any time, so you could be using a temporary fscreate value, or your new value could be overwritten immediately by writing to /proc/$$/attr/fscreate I think we need to add a separate field for this purpose, which can only be written to via the in-kernel API and overrides fscreate. > I have to call the function twice per cache op: once to set the file > creation security ID and once to restore it back to what it was. > > However, what happens if I can't restore the original security ID (perhaps the > rules changed between the two invocations)? I can't let the task continue as > it's now running with the wrong security... Kill the task? - James -- James Morris - 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/