Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750762AbWAJMCD (ORCPT ); Tue, 10 Jan 2006 07:02:03 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751079AbWAJMCD (ORCPT ); Tue, 10 Jan 2006 07:02:03 -0500 Received: from boogie.lpds.sztaki.hu ([193.225.12.226]:42983 "EHLO boogie.lpds.sztaki.hu") by vger.kernel.org with ESMTP id S1750762AbWAJMCC (ORCPT ); Tue, 10 Jan 2006 07:02:02 -0500 Date: Tue, 10 Jan 2006 13:01:52 +0100 From: Gabor Gombas To: Matthew Garrett Cc: Andreas Gruenbacher , Matthew Garrett , Andrew Morton , linux-kernel@vger.kernel.org, Linus Torvalds Subject: Re: [patch 0/2] Tmpfs acls Message-ID: <20060110120152.GA27480@boogie.lpds.sztaki.hu> References: <200601090023.16956.agruen@suse.de> <200601100059.47317.agruen@suse.de> <20060110000758.GA22399@srcf.ucam.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060110000758.GA22399@srcf.ucam.org> X-Copyright: Forwarding or publishing without permission is prohibited. Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1295 Lines: 28 On Tue, Jan 10, 2006 at 12:07:58AM +0000, Matthew Garrett wrote: > Handwavy problem scenario - user A logs in, is given access to the > soundcard. Starts running a program that when given appropriate signals > will record from the system microphone. Logs out. Waits for user B, who > he suspects is having an affair with his wife, and then monitors any > conversations that user B has. ACLs on their own don't seem to solve > this any more than just statically assigning group membership to users. This scenario is not a permission but a locking problem. User B should just claim the microphone exclusively and that should fail if user A keeps an fd open. For the generic case maybe a new lock type would be useful, that would fail iff a process with a different effective UID keeps the device open. Gabor -- --------------------------------------------------------- MTA SZTAKI Computer and Automation Research Institute Hungarian Academy of Sciences --------------------------------------------------------- - 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/