Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934050Ab1ETPSD (ORCPT ); Fri, 20 May 2011 11:18:03 -0400 Received: from smtp.outflux.net ([198.145.64.163]:48319 "EHLO smtp.outflux.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933917Ab1ETPSC (ORCPT ); Fri, 20 May 2011 11:18:02 -0400 Date: Fri, 20 May 2011 08:17:31 -0700 From: Kees Cook To: Greg KH Cc: Vasiliy Kulikov , linux-kernel@vger.kernel.org, Eugene Teo Subject: Re: [RFC] add mount options to sysfs Message-ID: <20110520151731.GT25448@outflux.net> References: <20110518163951.GA24143@suse.de> <20110518170545.GA4435@albatros> <20110518191727.GA26741@suse.de> <20110519062622.GA4418@albatros> <20110519171227.GB22019@suse.de> <20110520095920.GA4489@albatros> <20110520133044.GC10225@suse.de> <20110520133451.GA8112@albatros> <20110520133615.GB8112@albatros> <20110520135424.GA10878@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110520135424.GA10878@suse.de> Organization: Canonical X-HELO: www.outflux.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1249 Lines: 33 Hi Greg, On Fri, May 20, 2011 at 06:54:24AM -0700, Greg KH wrote: > That's the question for you, we would be changing the kernel/user api > here, and odds are, something will break. I feel like this is going in circles. :) Adding this feature (with no changes to the defaults) will: - not break anything in the standard case - allow a system owner to locally choose the DAC perms on the mounts The question is about providing a temporal buffer between when a flaw is found in sysfs or debugfs and when the fix for it gets to the system owner. This, of course, presupposes that flaws are even publicly discovered in the first place. It gives paranoid system owners the option to lock down sysfs and debugfs from non-root users while still having them mounted without needing to make rather non-standard changes to boot time scripts beyond changing the fstab. Given that things like tmpfs support these options, it seems only sane to suppor them here too. -Kees -- Kees Cook Ubuntu Security Team -- 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/