From owner-freebsd-current@FreeBSD.ORG Thu Jul 22 08:39:01 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id F1C9B16A4CE; Thu, 22 Jul 2004 08:39:01 +0000 (GMT) Received: from itchy.rabson.org (mailgate.nlsystems.com [80.177.232.242]) by mx1.FreeBSD.org (Postfix) with ESMTP id C550143D46; Thu, 22 Jul 2004 08:39:00 +0000 (GMT) (envelope-from dfr@nlsystems.com) Received: from ns0.nlsystems.com (ns0.nlsystems.com [80.177.232.243]) by itchy.rabson.org (8.12.11/8.12.11) with ESMTP id i6M8cj1G087146; Thu, 22 Jul 2004 09:38:46 +0100 (BST) (envelope-from dfr@nlsystems.com) From: Doug Rabson To: Hidetoshi Shimokawa Date: Thu, 22 Jul 2004 09:38:40 +0100 User-Agent: KMail/1.6.1 References: <16634.47272.768935.436137@grasshopper.cs.duke.edu> <1090421941.7114.26.camel@builder02.qubesoft.com> <87u0w1ni2i.wl@tora.nunu.org> In-Reply-To: <87u0w1ni2i.wl@tora.nunu.org> MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <200407220938.40393.dfr@nlsystems.com> X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.63 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on itchy.rabson.org X-Virus-Scanned: clamd / ClamAV version 0.71, clamav-milter version 0.71 X-Virus-Status: Clean cc: simokawa@freebsd.org cc: freebsd-current@freebsd.org cc: Andrew Gallatin Subject: Re: Excellent job on the firewire support! X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 22 Jul 2004 08:39:02 -0000 On Wednesday 21 July 2004 22:53, Hidetoshi Shimokawa wrote: > At Wed, 21 Jul 2004 15:59:01 +0100, > > Doug Rabson wrote: > > > If no, assuming I had a Windows or Linux box on the firewire bus, > > > would it be possible to access physical memory from a different > > > OS? > > > > Windows XP has some kind of firewire debug driver that you might > > have to load (I haven't read the docs on that). I don't think the > > linux driver enables physical access by default but it would be > > easy to hack it in (just write all ones to the right fwohci > > register). > > The physical access is usually used for SBP-2 initiator mode. > Without physical access, the performance of SBP-2 should be > poorer and we see more load on CPU. > > The physical access can be restricted by two way. You can > restrict it per node-id and by physical memory range(upper bound). My vague plan was for the SBP driver to enable physical access from the SBP node. This could be done on a transaction basis so that we enable it before posting a transaction and disabled it when all current transactions have completed. > > As far as I have tried, WindowsXP seems not to allow physical access > of usual nodes. But I think you can easily cheat it by a node with > sbp target mode(use sbp_targ(4) ;-). If you can avoid enabling access for drives that you are not actually using, this might not be that bad. Defaulting to auto-login means that an attacker would have plenty of opportunity though. > > In my opinion, it's hard to ensure security with current OHCI > specification. In practice, any attacker is likely to be only a few meters away so the best defense is probably to just reach over and hit them :-)