Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751403AbWHVRgh (ORCPT ); Tue, 22 Aug 2006 13:36:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751408AbWHVRgh (ORCPT ); Tue, 22 Aug 2006 13:36:37 -0400 Received: from mailout1.vmware.com ([65.113.40.130]:7899 "EHLO mailout1.vmware.com") by vger.kernel.org with ESMTP id S1751403AbWHVRgg (ORCPT ); Tue, 22 Aug 2006 13:36:36 -0400 Message-ID: <44EB40A3.50700@vmware.com> Date: Tue, 22 Aug 2006 10:36:35 -0700 From: Zachary Amsden User-Agent: Thunderbird 1.5.0.5 (X11/20060719) MIME-Version: 1.0 To: Andi Kleen Cc: virtualization@lists.osdl.org, Adrian Bunk , Andrew Morton , Chris Wright , Linux Kernel Mailing List , Alan Cox , Arjan van de Ven Subject: Re: [PATCH] paravirt.h References: <1155202505.18420.5.camel@localhost.localdomain> <200608221550.57603.ak@muc.de> <20060822142519.GX11651@stusta.de> <200608221654.10558.ak@muc.de> In-Reply-To: <200608221654.10558.ak@muc.de> 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: 1813 Lines: 45 Andi Kleen wrote: > On Tuesday 22 August 2006 16:25, Adrian Bunk wrote: > >> On Tue, Aug 22, 2006 at 03:50:57PM +0200, Andi Kleen wrote: >> >>>> this would need a "const after boot" section; which is really not hard >>>> to make and probably useful for a lot more things.... todo++ >>>> >>> except for anything that needs tlb entries in user space. And it only gives you >>> false sense of security. --todo >>> >> What's the alternative? >> > > The alternative is to not protect it, since protecting it doesn't > offer any significant additional security over not protecting it. > Didn't someone point out yet that if you are vulnerable to someone loading a kernel module of their choosing, you lose, plain and simple? You don't need paravirt-ops to implement a rootkit, and it doesn't make it any easier, and write protecting it is totally useless. How do you think VMware runs on Linux? It takes over the hardware entirely, loads a hypervisor, and starts running in a completely different world. And it doesn't even need to use a single _GPL'd export to do that. Write protection is great as a debug option to find accidental memory corruptions. It is useless as a technique to prevent subversion. Um hello, you're already at CPL-0. Just rewrite the page tables already. >> Change it from a struct to a compile time choice? >> > > One of the design goals of paravirt-ops was to allow single binaries > that run on both native hardware and on hypervisors. So that would > be a non starter. Strongly agree. Zach - 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/