Bug#1051785: gdm3 won't allow logins when a smartcard/yubikey is plugged

[Marco Trevisan]

On giu 12 2025, at 4:40 pm, Simon McVittie <smcv at debian.org> wrote:

> On Thu, 12 Jun 2025 at 16:12:15 +0200, Marco Trevisan wrote:
>> On giu 12 2025, at 3:18 pm, Simon McVittie <smcv at debian.org> wrote:
>> In debian we actually have the `gdm-auth-config` that should allow to
>> manage this without having to handle this, it also allows to use distro
>> scripts (I did put one in our gdm's debian/* folder) that should handle
>> things, but it may need tunings since my testing was quite in the past
>> compared to when it landed upstream.
>> 
>> So... I feel that such tool should be instead used to setup things,
>> while it can be used by sysadmins quickly, in theory, to enable it back
> 
> Are you aware of the issue reported as #1051785?

I think a similar thing was reported in ubuntu too, but I had not enough
time to fully handle it, however IIRC another option may be to use use 
update-alternatives --config gdm-smartcard pointing to
/etc/pam.d/gdm-smartcard-sssd-or-password instead?

That would control the PAM service that is used by gdm by default, we
could also add a NULL value to it to disable it completely instead