Re: Code sharing between system and home services (was Re: On the naming of System and Home services modules.)

[Ludovic Courtès]

Maxime Devos <maximedevos@telenet.be> skribis:

> Ludovic Courtès schreef op za 02-10-2021 om 16:27 [+0200]:
>> Maxime Devos <maximedevos@telenet.be> skribis:
>> 
>> > Ludovic Courtès schreef op di 28-09-2021 om 14:21 [+0200]:
>> > > Hi,
>> > > 
>> > > Joshua Branson <jbranso@dismail.de> skribis:
>> > > 
>> > > > Apologies if I'm speaking for something I know very little
>> > > > about...Wouldn't it be nice if guix home services would accept a user
>> > > > and a group field?  For the syncthing service, perhaps the user wants 
>> > > > to
>> > > > limit Syncthing's runtime permissions.  So instead of running as the
>> > > > user, the user would run synthing as a different user with less 
>> > > > permissions?
>> > > 
>> > > That’s not possible unless the calling user is root, since you’d need
>> > > the ability to switch users somehow.
>> > 
>> > On Debian, a user has a list of ‘subordinate user IDs’ which can be 
>> > switched
>> > to without root: 
>> > <https://manpages.debian.org/buster/uidmap/newuidmap.1.en.html>;.
>> > 
>> > Maybe "guix home" could use that mechanism, and this mechanism could be 
>> > implemented
>> > on Guix System as well?
>> 
>> Yes but that requires unprivileged user namespaces, which may or may not
>> be supported—e.g., likely unsupported when using Home on a foreign
>> distro.
>
> I don't recall newuidmap requiring unprivileged user namespaces -- it's a 
> setuid binary.

Ah right.  But we’re not call do (system* "/usr/sbin/newuidmap") in
service code, so that’s still a problem, no?

Thanks,
Ludo’.