Subject: Re: bug#43421: Encoding issue in exported archive signatures
From: Ludovic Courtès <[email-masked]>
To: [email-masked]
Date: Tue, 15 Sep 2020 17:42:24 +0200
List-Id: <debbugs-submit.debbugs.gnu.org>

Hi,

Ludovic Courtès <[email-masked]> skribis:

> Following the ‘guix authenticate’ in commit
> 64cf660f872fb7aaf0d2b463e45b4c756297f743¹, I’m observing encoding
> issues:
>
>   guix archive --export \
>     /gnu/store/3p5wcw2a0844rbcmlrqfjx8bx7b7gq34-r-rvest-0.3.6-guile-builder
>
> yield an archive with this signature:
>
> (signature
>  (data
>   (flags rfc6979)
>   (hash sha256 #1DEE0418AF5FD8A05D2142290BA03735176FA27BB68B3A02977C774EA3DBDAEC#)
>   )
>  (sig-val
>   (ecdsa
>    (r #072B8E5C6B84D4ED469EC2CF63103621602E9AF3902E454CAD49CFA6BDE2FBF0#)
>    (s "~%*Øw2%YZ»+yvc*¤Ì44C;RM\t3EQIp<ü")
>    )
>   )
>  (public-key
>   (ecc
>    (curve Ed25519)
>    (q #8D156F295D24B0D9A86FA5741A840FF2D24F60F7B6C4134814AD55625971B394#)
>    )
>   )
>  )
>
> Notice the ‘s’ field of the signature.
>
> The problem does not occur systematically: it depends on the byte string
> (libgcrypt encodes Latin-1ish strings as strings and other strings as
> hex sequences.)  The problem is similar to <https://issues.guix.gnu.org/17312>.

Fixed in b911d6547444b5f8d17b224bafa5ee1b5aafaff5!

> The interesting bit is that this archive can be correctly ingested by a
> new daemon, but it fails signature verification with an older daemon.

This is because when using the new daemon on both sides, we were
encoding/decoding strings as UTF-8, which made no sense but worked
well.  Older implementations rightfully expect “raw strings”
aka. ISO-8859-1.

Ludo’.