From owner-freebsd-chat Wed Oct 15 23:19:29 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id XAA08202 for chat-outgoing; Wed, 15 Oct 1997 23:19:29 -0700 (PDT) (envelope-from owner-freebsd-chat) Received: from obie.softweyr.ml.org ([199.104.124.49]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id XAA08197 for ; Wed, 15 Oct 1997 23:19:26 -0700 (PDT) (envelope-from wes@xmission.com) Received: (from wes@localhost) by obie.softweyr.ml.org (8.7.5/8.6.12) id AAA12395; Thu, 16 Oct 1997 00:24:51 -0600 (MDT) Date: Thu, 16 Oct 1997 00:24:51 -0600 (MDT) Message-Id: <199710160624.AAA12395@obie.softweyr.ml.org> From: Wes Peters To: Mike Smith CC: chat@freebsd.org Subject: Re: C2 Trusted FreeBSD? In-Reply-To: <199710150140.LAA00804@word.smith.net.au> References: <199710150140.LAA00804@word.smith.net.au> Sender: owner-freebsd-chat@freebsd.org X-Loop: FreeBSD.org Precedence: bulk Mike Smith writes: > Please note that I am *not* questioning whether, given analog access to > the storage device, previous data state(s) can be recovered; this is a > given. > > What I *am* questioning is why this is a requirement in a purely > software environment, where it is not possible via software to > determine anything other than the current value of a given storage > location. > > The only methods for obtaining the previous contents of a storage > location involve physical analog access to the hardware, and if you > have this then system security has already been compromised because you > could have recorded the original value when it was current. Not according to the crowd of ex-Iomega engineers I work with. With access to the head controls and the data splitter (i.e. poking around behaving like a device driver) you can do some pretty mysterious things to a disk drive. With more modern devices like IDE and SCSI, where the controller is embedded on the drive and you have limited access to the data stream, this is probably not quite so true, but still dangerous enough you're not going to convince the US gummint to change their collective mind (sic). -- "Where am I, and what am I doing in this handbasket?" Wes Peters Softweyr LLC http://www.xmission.com/~softweyr softweyr@xmission.com