bug#40115: [PATCH] download: Use correct system and guile in 'url-fetch/tarbomb' and 'url-fetch/zipbomb'.

[Ludovic Courtès]

Hi Diego,

Diego Nicola Barbato <address@hidden> skribis:

>>From 85594ce40c98ac5763b8295e2358567c6920188e Mon Sep 17 00:00:00 2001
> From: Diego Nicola Barbato <address@hidden>
> Date: Mon, 16 Mar 2020 18:43:20 +0100
> Subject: [PATCH] download: Use correct system and guile in 'url-fetch/tarbomb'
>  and 'url-fetch/zipbomb'.
>
> Previously the result of `guix build -s $system $package' would depend on the
> system Guix was built for if $package or one of its dependencies used
> 'url-fetch/tarbomb' or 'url-fetch/zipbomb' as the origin method of its
> source (e.g. `guix build -s i686-linux ffmpeg' on i686-linux would build a
> different derivation than on x86_64-linux).
>
> This patch fixes this by explicitly passing the correct system and guile to
> 'gexp->derivation'.
>
> * guix/download.scm (url-fetch/tarbomb): Pass #:system system and
>   #:guile-for-build guile to 'gexp->derivation', where guile is the derivation
>   of guile for system.
>   (url-fetch/zipbomb): Likewise.

Good catch, pushed as c1d81df93d4b67671fc4a8e0a80c0f02c5821663!

>> builds a different derivation on i686-linux than on x86_64-linux.  This
>> doesn't just affect ffmpeg but a whole class of packages which use or
>> depend on a package that uses 'url-fetch/tarbomb' or 'url-fetch/zipbomb'
>> as the origin method of its source.  That's around 334 packages, among
>> them diffoscope, enlightenment, gnome, ungoogled-chromium, and wine.
>
> The number (348 for commit 151f3d4) and full list of affected packages
> can be computed by loading the attached script [0] into `guix repl' and
> running `(show-affected-packages)'.

Terrible that ci. has been building useless substitutes for these
packages and that users of non-x86_64 platforms were not getting
substitutes.

Thanks a lot for the patch and detailed analysis!

Ludo’.