Intermittent data corruption in gpg 1.2.0

Werner Koch
Tue Dec 17 12:17:02 2002

On Tue, 17 Dec 2002 08:11:07 +0000, judy m down said:

> $ find /var/lib/dpkg/available /var/lib/dpkg/available |
> 	afio -oz -Z -U \
> 			-P gpg \
> 			-Q --batch \
> 			-Q --no-options \
> 			-Q --homedir -Q $homedir \
> 			-Q --always-trust \
> 			-Q --no-auto-check-trustdb \
> 			-Q --recipient -Q "${qid:?}" \
> 			-Q --debug-all -Q -vv \
> 			-Q -e \
> 			-3 0 \
> 			"$qofile"

It is too long ago that I hacked on afio, but there might be a problem
with the double compression.  gpg already compresses; you might want
to add "-Q z -Q 0", so that gpg does not compress the data - however,
this has the disadvantage that afio won't be able to do any compression
(there is not much to compress in encrypted data).  So the better
solution is to drop the "-Z" option.

Of course there is still a bug somewhere:

> afio: "/var/lib/dpkg/available.z": Error zipping file, written damaged copy
> to archive.

I am not sure whether afio still pipes through gzip; maybe there is a
problem running 2 filters on the data.  Another thing to look into is
what happens if the compressedn data gets largers than the input -
this is very likely when trying to compress encrypted data.