Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263133AbVBCVt4 (ORCPT ); Thu, 3 Feb 2005 16:49:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263120AbVBCVtz (ORCPT ); Thu, 3 Feb 2005 16:49:55 -0500 Received: from gizmo06bw.bigpond.com ([144.140.70.41]:26787 "HELO gizmo06bw.bigpond.com") by vger.kernel.org with SMTP id S263397AbVBCVs1 (ORCPT ); Thu, 3 Feb 2005 16:48:27 -0500 Message-ID: <42029C23.1000300@bigpond.net.au> Date: Fri, 04 Feb 2005 08:48:19 +1100 From: Peter Williams User-Agent: Mozilla Thunderbird 0.9 (X11/20041127) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Paul Davis CC: "Bill Huey (hui)" , Ingo Molnar , "Jack O'Quin" , Nick Piggin , Con Kolivas , linux , rlrevell@joe-job.com, CK Kernel , utz , Andrew Morton , alexn@dsv.su.se, Rui Nuno Capela , Chris Wright , Arjan van de Ven Subject: Re: [patch, 2.6.11-rc2] sched: RLIMIT_RT_CPU_RATIO feature References: <200502031420.j13EKwFx005545@localhost.localdomain> In-Reply-To: <200502031420.j13EKwFx005545@localhost.localdomain> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1675 Lines: 36 Paul Davis wrote: > > There are several kernel-side attributes that would make JACK better from > my perspective: > > * better ways to acquire and release RT scheduling I'm no expert on the topic but it would seem to me that the mechanisms associated with the capable() function are intended to provide a consistent and extensible interface to the control of privileged operations with possible finer grained control than "root 'yes' and everybody else 'no'". Maybe the way to solve this problem is to modify the interpretation of capable(CAP_SYS_NICE) so that it returns true when invoked by a task setuid to a nominated uid in addition to zero? By default, this additional uid would be set to zero (i.e. not change to current capabilities) but a mechanism to allow a suitable privileged user to change it could be provided. Programs which the sysadmin wishes to be allowed to acquire RT scheduling even when used by ordinary users could be setuid to this "RT user". If the account for the "RT user" was properly configured (e.g. not allowed to log in, no home directory, etc.) then the damage that could be done by tasks run as setuid "RT user" would be limited. Peter PS Maybe SELinux already provides this functionality or something better? -- Peter Williams pwil3058@bigpond.net.au "Learning, n. The kind of ignorance distinguishing the studious." -- Ambrose Bierce - 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/