Bug#1107934: gdm3: disable-user-list=true stopped working after upgrade from bookworm to trixie

[Jeremy Bícha]

On Tue, Jun 17, 2025 at 3:01 PM Jeremy Bícha <jeremy.bicha at canonical.com> wrote:
>
> On Tue, Jun 17, 2025 at 2:11 PM Robert Jaeschke <robert-j at gmx.de> wrote:
> > in bookworm I had successfully disabled the user list in the gdm login screen
> > by following those instructions: https://help.gnome.org/admin/system-admin-
> > guide/stable/login-userlist-disable.html.en
> >
> > After upgrading to trixie this no longer works.
>
> I don't believe those instructions can work as is. Debian has named
> the system user Debian-gdm instead of gdm so I think you may need to
> substitute Debian-gdm for gdm every time gdm is mentioned on that
> page.

There is this changelog entry from gdm3  45.0.1-1 so yes, your
previous configuration no longer works after upgrading from bookworm
to trixie.

  * d/gdm3.links: Create a dconf profile named for the Debian-gdm user.
    In upstream and Ubuntu gdm, the system username used for the greeter
    is "gdm", but in Debian, for historical reasons it is "Debian-gdm".
    Before version 45, the dconf profile name "gdm" was hard-coded,
    but since version 45 it uses a profile name that matches the system
    username (to allow gnome-initial-setup to have its own profile).
    This resulted in the gdm greeter trying to use the ordinary
    gnome.session instead of gnome-login.session, which caused login to
    fail when the gnome-session package was not installed, and caused
    settings in /etc/gdm3/greeter.dconf-defaults to be ineffective. Other
    differences between gnome.session and gnome-login.session, potentially
    including security hardening for the greeter, would also not have
    been effective.
    (Closes: #1052374, #1051671, #1051993)

Thank you,
Jeremy Bícha