Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757482AbZLDWZc (ORCPT ); Fri, 4 Dec 2009 17:25:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755328AbZLDWZ2 (ORCPT ); Fri, 4 Dec 2009 17:25:28 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:39945 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754446AbZLDWZZ (ORCPT ); Fri, 4 Dec 2009 17:25:25 -0500 Date: Fri, 4 Dec 2009 23:25:24 +0100 From: Pavel Machek To: "H. Peter Anvin" Cc: Andi Kleen , "Cihula, Joseph" , "Wang, Shane" , "Rafael J. Wysocki" , "linux-kernel@vger.kernel.org" , Ingo Molnar , "arjan@linux.intel.com" , "chrisw@sous-sol.org" , "jmorris@namei.org" , "jbeulich@novell.com" , "peterm@redhat.com" Subject: Re: [PATCH] intel_txt: add s3 userspace memory integrity verification Message-ID: <20091204222524.GF32314@elf.ucw.cz> References: <4A9CE0B2.5060608@intel.com> <4ABF2B50.6070106@intel.com> <20091004185801.GC1378@ucw.cz> <037F493892196B458CD3E193E8EBAD4F01F03277DF@pdsmsx502.ccr.corp.intel.com> <20091204081933.GE1540@ucw.cz> <4F65016F6CB04E49BFFA15D4F7B798D9AEDDD4C5@orsmsx506.amr.corp.intel.com> <20091204171333.GS18989@one.firstfloor.org> <4B194CA1.3070106@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4B194CA1.3070106@zytor.com> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1341 Lines: 30 On Fri 2009-12-04 09:53:37, H. Peter Anvin wrote: > On 12/04/2009 09:13 AM, Andi Kleen wrote: > >>> > >>> So no, you did not audit do_suspend_lowlevel to make sure it does not > >>> follow function pointers. Bad. > >> > >> We aren't aware of any code or data used by the resume path that is outside of the tboot-MAC'ed regions above--if you can point out any then we will gladly address them. > > > > Code coverage is not enough, you need data coverage too. If someone > > modifies kernel data it's typically easy to subvert code as a next step. > > > > The only function pointers that are invoked on the do_suspend_lowlevel > path are some paravirt_crap pointers, but those are located inside > kernel static data. What guarantees kernel static data are below 4GB? What prevents me from booting with funny memmap where first 1MB is mapped, and then memory above 4GB? What prevents Chinese company to ship machine with such funny memmap? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- 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/