Bug#932047: lightdm: greeter session support for elogind

[Mark Hindley <mark@hindley.org.uk>]

Yves-Alexis,

On Sun, Oct 09, 2022 at 01:46:56PM +0200, Yves-Alexis Perez wrote:
> for some reason it seems I never actually replied to this bug, sorry.

No worries.

> I might have replied on different bugs, but I'm not really keen on modifying
> pam files, especially for specific / non-default stuff.

Yes, I remember that from our previous discussions.

> Do you know what are the opinion of PAM people and systemd-logind people on
> that?

Added to CC:

Dear Steve and Sam as PAM maintainers,

I am wanting to add libpam-elogind support to lightdm-greeter. Currently
/etc/pam.d/lightdm-greeter hooks logind directly with

  session   optional pam_systemd.so

I have proposed two patches: either to add

 session   optional pam_elogind.so

or replace both with

 @include common-session

Yves-Alexis is understandably cautious about changing the PAM configuration.  Do
you have any thoughts, advice or comments on which might be the most appropriate?

Thanks

> It might be nice to have them chime in. Also not sure how this thing is
> handled on other DM, any idea?

A quick look shows most use '@include common-session'. AFAICS that is the case for

 gdm3: /etc/pam.d/gdm-password 
 sddm: /etc/pam.d/sddm-greeter
 xdm: /etc/pam.d/xdm
 slim: /etc/pam.d/slim (although it doesn't use logind interfaces)

AFAICS lxdm doesn't use logind at all.

HTH.

Best wishes

Mark