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To: ticso@cicely.de
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
In-Reply-To: Your message of "Thu, 03 Mar 2005 13:04:22 +0100."
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Date: Thu, 03 Mar 2005 13:18:45 +0100
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cc: tech-security@NetBSD.org
cc: Roland Dowdeswell <elric@imrryr.org>
cc: hackers@freebsd.org
Subject: Re: FUD about CGD and GBDE 
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In message <20050303120421.GW86348@cicely12.cicely.de>, Bernd Walter writes:

>No matter what disk you take - writes never have been atomic.
>The major difference I see is that you get a read error back in
>the disk failure case, while such a crypto failure produces more or
>less random data without any error.
>Mounting unclean filesystems rw for bg_fsck can be considered
>dangerous with such unexpected data corruption.
>And how would you know that a restore from backup is required for
>a damaged file?

100% true.

The trouble is that it would cost a lot in performance and a doubling
in metadata to protect yourself against this.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.