Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S271289AbTHCVsC (ORCPT ); Sun, 3 Aug 2003 17:48:02 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S271283AbTHCVsC (ORCPT ); Sun, 3 Aug 2003 17:48:02 -0400 Received: from outpost.ds9a.nl ([213.244.168.210]:43139 "EHLO outpost.ds9a.nl") by vger.kernel.org with ESMTP id S271289AbTHCVrj (ORCPT ); Sun, 3 Aug 2003 17:47:39 -0400 Date: Sun, 3 Aug 2003 23:47:38 +0200 From: bert hubert To: David Lang Cc: Andrew Morton , linux-kernel@vger.kernel.org, devik@cdi.cz, aebr@win.tue.nl Subject: Re: [PATCH] Allow /dev/{,k}mem to be disabled to prevent kernel from being modified easily Message-ID: <20030803214738.GA16129@outpost.ds9a.nl> Mail-Followup-To: bert hubert , David Lang , Andrew Morton , linux-kernel@vger.kernel.org, devik@cdi.cz, aebr@win.tue.nl References: <20030803140031.7665546c.akpm@osdl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.3.28i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1432 Lines: 35 On Sun, Aug 03, 2003 at 02:33:01PM -0700, David Lang wrote: > we already have the option to not support modules (as Alan Cox points out > every time that subject comes up it can be bypassed by people who have > access to /dev/*mem) so it would seem that adding the option to bar access > to /dev/*mem as well would make exisitng config options mean what they > appear to mean. This was also on my mind, yes. As Wichert said, not all holes are closed then, there is also /dev/microcode, iopl() and more. However, perhaps we could all sweep them under the "don't allow userspace to touch kernel memory easily" banner? We can leave more finegrained tools to outside patchsets then. I think root will always be able to figure out a way to get into the kernel's innards, but we can raise the bar quite a lot easily without too much infrastructure. As to what Alan said about LSM, I've yet to see how to do that in a reasonable way. But I didn't look too hard. As to what Andries said, how about '/proc/sys/raw_memory_access'? Thanks. -- http://www.PowerDNS.com Open source, database driven DNS Software http://lartc.org Linux Advanced Routing & Traffic Control HOWTO - 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/