From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753507AbXDCQDb (ORCPT ); Tue, 3 Apr 2007 12:03:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753509AbXDCQDb (ORCPT ); Tue, 3 Apr 2007 12:03:31 -0400 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:2696 "EHLO spitz.ucw.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753507AbXDCQDa (ORCPT ); Tue, 3 Apr 2007 12:03:30 -0400 Date: Tue, 3 Apr 2007 16:03:07 +0000 From: Pavel Machek To: Tasos Parisinos Cc: Andi Kleen , herbert@gondor.apana.org.au, linux-kernel@vger.kernel.org, randy.dunlap@oracle.com, indan@nul.nu Subject: Re: [PATCH resend][CRYPTO]: RSA algorithm patch Message-ID: <20070403160307.GA5266@ucw.cz> References: <4610D25F.7080005@ceid.upatras.gr> <4610EDF9.9000601@sciensis.com> <20070402132820.GA28983@one.firstfloor.org> <46111D03.5020905@sciensis.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <46111D03.5020905@sciensis.com> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > >>The best environment to deploy such functionality is > >>in updating by remote, > >>executable code (programs, libs and modules) on > >>embedded devices running > >>Linux, that have some form of kernel physical > >>security, so one can't > > > >How would that physical security look like? Would it > >include DMA > >protection? > > > >For example to do any useful form of graphics you need > >user controllable DMA, which can normally touch > >everything. > >There are various other similar "backdoors" for root. > > > >I'm somewhat sceptical because all kernels will need > >access > >to the direct mapping to operate and there are also > >various > >interfaces that can be as root (ab)used to change it. > > > >And when you can do that they can change function > >pointers > >and jump to arbitary code or change the kernel page > >tables > >and map arbitary code. > > > >Disallowing all this would probably end up with a quite > >useless kernel. > > > > > >>There are already some systems that implement and > >>utilize such functionality that > >>use windows platforms, and other Linux distros that > >>use userland > > > >Yes, at least the Vista variant was just broken. And > >its designers spent > >a lot of effort on it, but it didn't help. > > > Please read the thread i gave you for some details for > things you ask > > Have in thought that we mostly talk here about embedded > devices > that run Linux in a very restricted environment where > only specific > applications are allowed to exist and run, there are no > user logons > and these applications need to be updated by remote once > in a while > over public networks. These applications need not be > tampered with What kind of applications are we talking about here? I'd like to hack hardware I own. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html