From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752529Ab2IPMRz (ORCPT ); Sun, 16 Sep 2012 08:17:55 -0400 Received: from out02.mta.xmission.com ([166.70.13.232]:49167 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752439Ab2IPMRx (ORCPT ); Sun, 16 Sep 2012 08:17:53 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Alan Cox Cc: "Serge E. Hallyn" , Aristeu Rozanski , Neil Horman , "Serge E. Hallyn" , containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Michal Hocko , Thomas Graf , Paul Mackerras , "Aneesh Kumar K.V" , Arnaldo Carvalho de Melo , Johannes Weiner , Tejun Heo , cgroups@vger.kernel.org, Paul Turner , Ingo Molnar References: <20120913205827.GO7677@google.com> <20120914183641.GA2191@cathedrallabs.org> <20120915022037.GA6438@mail.hallyn.com> <87wqzv7i08.fsf_-_@xmission.com> <20120915220520.GA11364@mail.hallyn.com> <87y5kazuez.fsf@xmission.com> <20120916122112.3f16178d@pyramind.ukuu.org.uk> <87sjaiuqp5.fsf@xmission.com> Date: Sun, 16 Sep 2012 05:17:44 -0700 In-Reply-To: <87sjaiuqp5.fsf@xmission.com> (Eric W. Biederman's message of "Sun, 16 Sep 2012 04:56:06 -0700") Message-ID: <87d31mupp3.fsf@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=;;;mid=;;;hst=in02.mta.xmission.com;;;ip=98.207.153.68;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX18UOX72LY7y8vnYzetT6Cio9EqFVd98L/c= X-SA-Exim-Connect-IP: 98.207.153.68 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.0 T_TM2_M_HEADER_IN_MSG BODY: T_TM2_M_HEADER_IN_MSG * -3.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% * [score: 0.0003] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa01 1397; Body=1 Fuz1=1 Fuz2=1] X-Spam-DCC: XMission; sa01 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Alan Cox X-Spam-Relay-Country: Subject: Re: Controlling devices and device namespaces X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Fri, 06 Aug 2010 16:31:04 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ebiederm@xmission.com (Eric W. Biederman) writes: > Alan Cox writes: > >>> One piece of the puzzle is that we should be able to allow unprivileged >>> device node creation and access for any device on any filesystem >>> for which it unprivileged access is safe. >> >> Which devices are "safe" is policy for all interesting and useful cases, >> as are file permissions, security tags, chroot considerations and the >> like. >> >> It's a complete non starter. Come to think of it mknod is completely unnecessary. Without mknod. Without being able to mount filesystems containing device nodes. The mount namespace is sufficient to prevent all of the cases that the device control group prevents (open and mknod on device nodes). So I honestly think the device control group is superflous, and it is probably wise to deprecate it and move to a model where it does not exist. Eric