Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757961AbXIFPGh (ORCPT ); Thu, 6 Sep 2007 11:06:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754947AbXIFPGa (ORCPT ); Thu, 6 Sep 2007 11:06:30 -0400 Received: from mail.fieldses.org ([66.93.2.214]:56528 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754108AbXIFPG3 (ORCPT ); Thu, 6 Sep 2007 11:06:29 -0400 Date: Thu, 6 Sep 2007 11:06:16 -0400 To: Satyam Sharma Cc: Trond Myklebust , Jan Engelhardt , Linux Kernel Mailing List Subject: Re: NFS4 authentification / fsuid Message-ID: <20070906150616.GA28565@fieldses.org> References: <1188484155.6755.38.camel@heimdal.trondhjem.org> <1188484337.6755.41.camel@heimdal.trondhjem.org> <1188486240.6755.51.camel@heimdal.trondhjem.org> <20070830214431.GF10808@fieldses.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.16 (2007-06-11) From: "J. Bruce Fields" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1064 Lines: 24 On Thu, Sep 06, 2007 at 01:44:05PM +0530, Satyam Sharma wrote: > /dev/kmem was just an example -- IMHO differentiating between kernel and > userspace from a security p.o.v. is always tricky. The things that come to mind are /dev/kmem and module-loading. What else is there? And what is it that makes this inherently difficult? > Like Trond said, there are very high number of ways in which > privileged userspace can compromise a running kernel if it really > wants to do that, root-is-God has always been *the* major problem with > Unix :-) > > The only _real_ way a kernel can lock itself completely against > malicious userspace involves trusted tamperproof hardware, The question of how to protect against someone with *physical* access certainly is more difficult, but surely that's a separate problem. --b. - 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/