[systemd-devel] Permissions adjustments for a greeter session

[Yves-Alexis Perez]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

Hey there,

I'm writing here as the Debian LightDM maintainer following a bug opened
against it (https://bugs.debian.org/1095999)

The reporter has issues with the greeter not showing on their install,
apparently because the lightdm-gtk-greeter process (runing as the lightdm
user) doesn't have permissions to access the /dev/dri/renderD128 node (and
it's apparently required for their mali gpu, and others).

Nowadays, afaict, the permissions on device nodes are usually handled by a
combination of udev and logind. For example on my graphical session the above
node has RW ACLs for my users, following (I guess) rules from
/lib/udev/rules.d/70-uaccess.rules

It seems that the greeter process doesn't have the same permissions (no ACLs)
and I'm not too sure why. In loginctl it's shown as a session of type
'greeter' so maybe it's related? Or maybe something else?

In any case, any help / pointer would be appreciated in order to properly fix
this issue for our users.

Thanks in advance, and if you need more information please ask!

Regards,
- -- 
Yves-Alexis
-----BEGIN PGP SIGNATURE-----

iQEzBAEBCAAdFiEE8vi34Qgfo83x35gF3rYcyPpXRFsFAmewqmsACgkQ3rYcyPpX
RFsY1ggAjdcUxyQ2N11XDmvvwKjkp6z3ncqjbDoDl23vbgLL2iroZoKR5Yao/M55
sIFfr4mWHST4ypg9CR2GtsDSZSBBvPX2fjjosKJP/7uCz5DhKhd47j67H+VtrQuh
MRafbSaE7gAY9yvmHcnuZwGtUJyipjrBv7O5XdOqmASJeqPD7LbSEC3QXcUJdxCM
UKzY5Vs0n1T+LmTyxnncIjuRO5S3PyLapLaSD5SnUjsRRdsxYIfbXwJWeoW8qeab
GdZMCWgP03gcdg4AtGZcle6qV5Vi/AgZYL7XAkowTXYvolk7RGekPRL7qHHtjSri
ImWtJYkQOC5BrxU+gWiWgLdPNwdqKQ==
=QCLN
-----END PGP SIGNATURE-----