Date: Thu, 20 May 1999 16:42:18 +1000 (EST) From: Darren Reed <darrenr@reed.wattle.id.au> To: wes@softweyr.com (Wes Peters) Cc: imp@harmony.village.org, ilmar@ints.ru, posix1e@cyrus.watson.org, freebsd-security@FreeBSD.ORG Subject: Re: secure deletion Message-ID: <199905200642.QAA11368@avalon.reed.wattle.id.au> In-Reply-To: <37438E4C.4B95B937@softweyr.com> from Wes Peters at "May 19, 99 10:23:40 pm"
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In some email I received from Wes Peters, sie wrote: > Warner Losh wrote: > > > > In message <Pine.BSF.4.05.9905191535110.7728-100000@ws-ilmar.ints.ru> "Ilmar S. Habibulin" writes: > > : May be it's an freebsd-fs@ question, but i think that it belings here to. > > : I heard that some linux fs (maybe extfs2?) have some secure deletion flag, > > : which being set on inode(file or dir) cause content of this file to be > > : wiped before deletion, so even if somebody manage to restore file, its > > : content would be unusable. I think, that it is nice feature, and i would > > : like to see it in freebsd. What would you say? > > : > > : PS. I have implementation of this feature for freebsd-2.2.5. May be i can > > : port it to 3.x. > > > > Does it doe the DoD recommended patter of deletion? That is overwrite > > the blocks with sever different series of bit patterns to make it > > impossible to recover using the usual techniques, or is it just a > > bzero of the blocks in question? The former is secure deletion, the > > latter is too insecure for most people that want this feature... > > The standard used to be 100 overwrites of 0xe5 then 0x5e, but they > changed the standard just as I was leaving the defense industry in > 1991. Does Posix or SUS have anything to say about this? I'd worry about this sort of thing when and if FreeBSD is ever used for storing of (officially) classified/confidential material and even then, the solution is likely to be to take a hammer or drill to the disks. For normal users, who are very unlikely to have any worries about someone doing an in-depth magnetic scan of their disk, a singal overwrite will be just as effect as 100. Lets try being a little realistic, eh ? Darren To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message
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