Bug 1886611

Summary:	lightdm creates extra, unwanted wtmp entries
Product:	[Fedora] Fedora EPEL	Reporter:	crxssi <crxssi>
Component:	lightdm	Assignee:	Alternative GTK desktop environments <alt-gtk-de-sig>
Status:	NEW ---	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	epel8	CC:	alt-gtk-de-sig, gp, leigh123linux, raveit65.sun, rdieter
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Hardware:	x86_64
OS:	Linux
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Embargoed:

Description crxssi 2020-10-08 21:44:44 UTC

I have lightdm-1.30.0-6.el8.x86_64 installed on CentOS 8.2 and set up to use XDMCP for my thin clients (and the greeter is lightdm-gtk-greeter).

The problem is that I am getting an extra, incomplete wtmp entry for each login when using lightdm that don't occur when I use gdm.  So "last" will look similar to this for every login/out:

# last user | head -2
user                  172.16.6.3:3     Thu Oct  8 15:19    gone - no logout
user     172.16.6.3:3                  Thu Oct  8 15:19 - 15:19  (00:00)

The second line is valid/complete, although it is missing data in the second column.  I believe it is being put in wtmp through this line in /etc/pam.d/lightdm:

session    optional    pam_lastlog.so silent

The first line is an extra, useless login entry that is not complete.  It is added regardless of what session type is selected by the user.  I have no idea where it is coming from or why it is there.  I spent many hours combing the 'net and config files and I just can't find it.

If I log into the CONSOLE (instead of through zephyr or a thin client), there are still two entries (which is not desired), but at least they are both complete:

user     tty1         :0               Thu Oct  8 14:27 - 14:27  (00:00)
user     :0                            Thu Oct  8 14:27 - 14:27  (00:00)

Since the only changes to the stock lightdm I made were:

[Seat:*]
greeter-hide-users=true
greeter-allow-guest=false
greeter-show-manual-login=true
allow-guest=false
[XDMCPServer]
enabled=true

I have to conclude that something about the packaging or operation of lightdm from EPEL under CentOS/RHEL 8.2 is not correct.  Thanks

Comment 1 crxssi 2020-10-09 14:17:44 UTC

I should clarify that for some reason, although lightdm is in EPEL, no greeter was provided or even available in EPEL (or other CentOS8 third-party repos).  Worse, I believe the EPEL package has a dependency on lightdm-gtk-greeter, so it can't even be installed without the default greeter.  To satisfy this, I was forced to install:

lightdm-gtk-2.0.5-1.fc28.x86_64
lightdm-gtk-greeter-settings-1.2.2-3.fc28.noarch

from Fedora 28.  I am pretty confident that the greeter is not responsible for anything related to wtmp entries (the purpose of this bug report), but I can't know that for sure.