Subject: Re: FUD about CGD and GBDE
To: None <>
From: Poul-Henning Kamp <>
List: tech-security
Date: 03/03/2005 13:18:45
In message <>, 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.