Re: [gdm-list] gdm-list Digest, Vol 120, Issue 1

[anonymous <johnandsara2 cox net>]

You can edit re-compile GDM if you have the skill and installation to do so.  If you cannot then have someone 
who can walk you through it.  It should be the easiest way to get what you want and teach you how to get what 
you want with *any* other such situation.

You can insure only one user can log-in to GDM.  There are a variety of strategies to do so.  The strategy 
*not* to use is to edit anything the the $HOME directory, since the user can edit these after login.

I’m unsure if you want to prevent *any* log-out (common for, say, a store “pos” point of sale terminal) or 
just prevent a sign-in as user you don’t list as a gdm user.

The lock screen “login as another user” likely just uses “log out” and then gdm login right? (if so, gdm 
configuration files are used in the process).

You may be able to edit gdm configuration files to tell it /home is say, /home2/, and then only users in 
/home2 can login to gdm.  That may help but not if gdm reads /etc/passwd to determine where a user’s home is. 
 Homeless users may cause login to fail.  On the other hand if it does, then you have a screen that is 
waiting for login.

One strange strategy is to edit /etc/passwd to not use /bin/sh as the user shell but a script which fails if 
a GDM login is being attempted.  However you should be aware that anyone with a root password OR ANYONE who 
can run chsh(1) (which runs as root) can simple change that entry.  It’s issues like this which should lead 
you back to saying “hey - it wont be too hard - i’ll just edit a few lines of gdm(1) and whala - it will do 
what i told it to do”.


> On Oct 4, 2016, at 8:00 AM, gdm-list-request gnome org wrote:
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> Today's Topics:
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>   1.  Disable User Switching on lockscreen (Laverne Schrock)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 3 Oct 2016 18:26:40 -0500
> From: Laverne Schrock <schr1230 morris umn edu>
> To: gdm-list gnome org
> Subject: [gdm-list] Disable User Switching on lockscreen
> Message-ID:
>       <CABMX+7RzgGQZcJN47XeFmCAuAQ1i4MqAajQtFMtq7ay1ET6qRQ mail gmail com>
> Content-Type: text/plain; charset=UTF-8
>
> Hi,
>
> I have a Fedora 24 system on which I would like to disable user switching.
> By following the steps listed here:
> https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Desktop_Migration_and_Administration_Guide/lockdown-logout.html
> I can remove the "Switch User" button from the system menu. However,
> the user can still lock the screen and then click "Log in as another user"
> right in GDM which defeats the purpose.
>
> So here is the question. Is there a way to enable screen locking and disable
> user switching on modern GDM?
>
> Thanks,
> Laverne Schrock
>
>
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> End of gdm-list Digest, Vol 120, Issue 1
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