From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.33) id 1CWaLR-0001JV-MG for qemu-devel@nongnu.org; Tue, 23 Nov 2004 08:04:33 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.33) id 1CWaKv-000177-Ur for qemu-devel@nongnu.org; Tue, 23 Nov 2004 08:04:04 -0500 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.33) id 1CWaKu-000165-JZ for qemu-devel@nongnu.org; Tue, 23 Nov 2004 08:04:01 -0500 Received: from [65.74.133.9] (helo=mail.codesourcery.com) by monty-python.gnu.org with esmtp (TLSv1:DES-CBC3-SHA:168) (Exim 4.34) id 1CWaBm-0004ZY-RZ for qemu-devel@nongnu.org; Tue, 23 Nov 2004 07:54:35 -0500 From: Paul Brook Subject: Re: [Qemu-devel] building a virus-proof PC with Qemu Date: Tue, 23 Nov 2004 12:54:31 +0000 References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200411231254.31623.paul@codesourcery.com> Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, Piotras On Tuesday 23 November 2004 12:31, Piotras wrote: > Hi! > > Imagine that with every byte stored on disk image, the emulated > memory and CPU registers we associate a flag indicating if the > byte come from "trusted" source. This information would propagate > with every memory/disk access (data-flow tracking). > > Before Qemu would translate a block of code the trusted bits could > be checked to see if the code is "trusted". Of course there are > issues with dynamic loaders, dynamic compilers, etc. And it's not > going to work well with scripted code. I'd expect you could do most of this on real hardware with the NX bit. You're going to need OS support in either case, so AFAICS all your qemu hack gives you is finer granularity (per-byte rather than per-page). Paul