Questions[gdmgreeting](server)

I would like to run a script after a user login. This script, using his kerberos tickets, will mount an SMB share.

Under RedHat 7 I could simply call the script from /etc/gdm/PreSession/Default and it would run fine. It would even preserve the $KRB5CCNAME when running the script while elevated (this variable is kept via a Defaults env_keep += "KRB5CCNAME" under sudoers.d.

Under Ubuntu 18.04 we use a service under /etc/systemd/user, which would use the ticket whenever there is a ticket.

With other words, under RHEL7 and Ubuntu, we could use the tickets even when elevated via sudo, either by running a user service or by calling the script from /etc/gdm/PreSession/Default.

Under RHEL8 we can't see the variable, neither when running the user service, nor when running it when calling it from /etc/gdm/PreSession/Default. When I log in as the user, I can see the variable, even when using sudo, so the environment variable is kept, but somehow it isn't available for the service nor for that script.

Could anyone help me how to fix this? I think I read somewhere that this might have something to do with how gdm is started under rhel8, but I'm not sure if that's the problem.

UPDATE: I see now that the scripts under /etc/gdm/PreSession/Default execute as root. I had the impression that they were executed as the user.

UPDATE2: It seems that I can use tickets anyway. I was assuming that they were not there, just because the $KRB5CCNAME was unset. But running a command that required the tickets worked anyway.

I'd like to customize the login screen on CentOS to limit the number of users displayed? I know how to disable the user's list by customizing the dconf gdm db but I wonder if I can set a limit value...

I have a RHEL 5 machine here which is a Dell Precision T3500.

I'm an Ubuntu guy, but I'm having a heck of a time with this machine.

After processing its first security update, we cannot log in via the gdm greeter. A new kernel was installed; then I installed the nVidia drivers for our Quadro NVS 295.

I know the X configuration is valid because the gdm greeter does display; however, upon login all we can get is a blank, black screen with a cursor.

I thought perhaps our python installation was corrupted but a reinstall via yum has not helped.

I have searched & googled extensively for a potential fix for this and can find nothing.

Below are outputs from uname, a tail of an error in /var/log/messages, and the Xorg.conf.

Can anyone suggest a course of action?

[sean@cheetah ~]$ uname -a
Linux cheetah.*.* 2.6.18-308.8.1.el5 #1 SMP Fri May 4 16:43:02 EDT 2012 x86_64 x86_64 x86_64 GNU/Linux

[sean@cheetah ~]$ sudo tail /var/log/messages
Jun  5 15:03:04 cheetah gconfd (sean-4592): Resolved address "xml:readonly:/etc/gconf/gconf.xml.defaults" to a read-only configuration source at position 2
Jun  5 15:03:05 cheetah hcid[3855]: Default passkey agent (:1.8, /org/bluez/applet) registered
Jun  5 15:03:05 cheetah pcscd: winscard.c:304:SCardConnect() Reader E-Gate 0 0 Not Found
Jun  5 15:03:05 cheetah last message repeated 2 times
Jun  5 15:03:06 cheetah gconfd (sean-4592): Resolved address "xml:readwrite:/home/sean/.gconf" to a writable configuration source at position 0
Jun  5 15:03:06 cheetah setroubleshoot: [program.ERROR] exception ImportError: /usr/lib/libatk-1.0.so.0: undefined symbol: g_assertion_message_expr Traceback (most recent call last):   File "/usr/bin/sealert", line 952, in ?     from setroubleshoot.gui_utils import *   File "/usr/lib/python2.4/site-packages/setroubleshoot/gui_utils.py", line 26, in ?     import gtk   File "/usr/lib64/python2.4/site-packages/gtk-2.0/gtk/__init__.py", line 48, in ?     from gtk import _gtk ImportError: /usr/lib/libatk-1.0.so.0: undefined symbol: g_assertion_message_expr
Jun  5 15:03:07 cheetah setroubleshoot: [program.ERROR] exception ImportError: /usr/lib/libatk-1.0.so.0: undefined symbol: g_assertion_message_expr Traceback (most recent call last):   File "/usr/bin/sealert", line 952, in ?     from setroubleshoot.gui_utils import *   File "/usr/lib/python2.4/site-packages/setroubleshoot/gui_utils.py", line 26, in ?     import gtk   File "/usr/lib64/python2.4/site-packages/gtk-2.0/gtk/__init__.py", line 48, in ?     from gtk import _gtk ImportError: /usr/lib/libatk-1.0.so.0: undefined symbol: g_assertion_message_expr
Jun  5 15:03:08 cheetah pcscd: winscard.c:304:SCardConnect() Reader E-Gate 0 0 Not Found
Jun  5 15:07:01 cheetah ntpd[4114]: synchronized to 64.16.211.38, stratum 3
Jun  5 15:07:01 cheetah ntpd[4114]: kernel time sync enabled 0001


[sean@cheetah ~]$ cat /etc/X11/xorg.conf
# nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig:  version 295.53  ([email protected])  Sat May 12 00:34:20 PDT 2012

# Xorg configuration created by system-config-display

Section "ServerLayout"
    Identifier     "single head configuration"
    Screen      0  "Screen0" 0 0
    InputDevice    "Mouse0" "CorePointer"
    InputDevice    "Keyboard0" "CoreKeyboard"
EndSection

Section "InputDevice"

    # generated from default
    Identifier     "Mouse0"
    Driver         "mouse"
    Option         "Protocol" "auto"
    Option         "Device" "/dev/input/mice"
    Option         "Emulate3Buttons" "no"
    Option         "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"
    Identifier     "Keyboard0"
    Driver         "kbd"
    Option         "XkbModel" "pc105"
    Option         "XkbLayout" "us"
EndSection

Section "Monitor"

 ### Comment all HorizSync and VertSync values to use DDC:
 ### Comment all HorizSync and VertSync values to use DDC:
    Identifier     "Monitor0"
    ModelName      "LCD Panel 1600x1200"
    HorizSync       31.5 - 74.7
    VertRefresh     56.0 - 65.0
    Option         "dpms"
EndSection

Section "Device"
    Identifier     "Videocard0"
    Driver         "nvidia"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Videocard0"
    Monitor        "Monitor0"
    DefaultDepth    24
    SubSection     "Display"
        Viewport    0 0
        Depth       24
    EndSubSection
EndSection

Update: Switching to the nv driver (which is installed) in xorg.conf resulted in no solution. I don't think that this is an X issue anymore.

Since there is a setroubleshoot error, I'm going to set SELinux to permissive and see if that helps.

Update: That didn't help. Anyone?

Update: Here's a more comprehensive tail of the messages log. You can see I tail'd it then went an logged in to the machine at 10:44, and this output is clearly the problem.

    [sean@cheetah ~]$ sudo tail -f /var/log/messages
Jun 27 10:17:05 cheetah smartd[4362]: Device /dev/sdb: using '-d sat' for ATA disk behind SAT layer. 
Jun 27 10:17:05 cheetah smartd[4362]: Device: /dev/sdb, opened 
Jun 27 10:17:06 cheetah smartd[4362]: Device: /dev/sdb, found in smartd database. 
Jun 27 10:17:06 cheetah smartd[4362]: Device: /dev/sdb, is SMART capable. Adding to "monitor" list. 
Jun 27 10:17:06 cheetah smartd[4362]: Monitoring 0 ATA and 2 SCSI devices 
Jun 27 10:17:06 cheetah smartd[4392]: smartd has fork()ed into background mode. New PID=4392. 
Jun 27 10:17:08 cheetah pcscd: winscard.c:304:SCardConnect() Reader E-Gate 0 0 Not Found
Jun 27 10:17:08 cheetah last message repeated 3 times
Jun 27 10:21:16 cheetah ntpd[4109]: synchronized to 46.166.138.172, stratum 2
Jun 27 10:21:16 cheetah ntpd[4109]: kernel time sync enabled 0001
Jun 27 10:44:49 cheetah gconfd (sean-4757): starting (version 2.14.0), pid 4757 user 'sean'
Jun 27 10:44:49 cheetah gconfd (sean-4757): Resolved address "xml:readonly:/etc/gconf/gconf.xml.mandatory" to a read-only configuration source at position 0
Jun 27 10:44:49 cheetah gconfd (sean-4757): Resolved address "xml:readwrite:/home/sean/.gconf" to a writable configuration source at position 1
Jun 27 10:44:49 cheetah gconfd (sean-4757): Resolved address "xml:readonly:/etc/gconf/gconf.xml.defaults" to a read-only configuration source at position 2
Jun 27 10:44:50 cheetah hcid[3851]: Default passkey agent (:1.8, /org/bluez/applet) registered
Jun 27 10:44:50 cheetah kernel: nm-applet[4821]: segfault at 0000000000000000 rip 0000000000000000 rsp 00007fff668d1d68 error 14
Jun 27 10:44:51 cheetah pcscd: winscard.c:304:SCardConnect() Reader E-Gate 0 0 Not Found
Jun 27 10:44:51 cheetah last message repeated 2 times
Jun 27 10:44:51 cheetah gconfd (sean-4757): Resolved address "xml:readwrite:/home/sean/.gconf" to a writable configuration source at position 0
Jun 27 10:44:51 cheetah setroubleshoot: [program.ERROR] exception ImportError: /usr/lib/libatk-1.0.so.0: undefined symbol: g_assertion_message_expr Traceback (most recent call last):   File "/usr/bin/sealert", line 952, in ?     from setroubleshoot.gui_utils import *   File "/usr/lib/python2.4/site-packages/setroubleshoot/gui_utils.py", line 26, in ?     import gtk   File "/usr/lib64/python2.4/site-packages/gtk-2.0/gtk/__init__.py", line 48, in ?     from gtk import _gtk ImportError: /usr/lib/libatk-1.0.so.0: undefined symbol: g_assertion_message_expr
Jun 27 10:44:52 cheetah setroubleshoot: [program.ERROR] exception ImportError: /usr/lib/libatk-1.0.so.0: undefined symbol: g_assertion_message_expr Traceback (most recent call last):   File "/usr/bin/sealert", line 952, in ?     from setroubleshoot.gui_utils import *   File "/usr/lib/python2.4/site-packages/setroubleshoot/gui_utils.py", line 26, in ?     import gtk   File "/usr/lib64/python2.4/site-packages/gtk-2.0/gtk/__init__.py", line 48, in ?     from gtk import _gtk ImportError: /usr/lib/libatk-1.0.so.0: undefined symbol: g_assertion_message_expr
Jun 27 10:44:54 cheetah pcscd: winscard.c:304:SCardConnect() Reader E-Gate 0 0 Not Found

I have to briefly describe the situation. We are planning to make a computer classroom with workstations running Ubuntu 10.04. Since making accounts for each student has not been considered reasonable, we decided to make accounts for each student group. We don't want students to share their passwords between groups so the solution would be not to give them passwords at all, but let the teacher log them in instead. Obviously he shouldn't go from one machine to another typing in credentials by hand, so we need some script that will connect to a remote machine by ssh and make GDM (or probably any other login manager if GDM cannot serve this purpose) log in specified user. I couldn't find any solutions, as well as I haven't noticed anybody in similar situation asking for help, so my question will be: can the scheme described be realized and if yes, then how? Thanks in advance.

I would like to disable the "gdmgreeting" application that is a graphical frontend, as I only want console interfaces. This application runs on vt7 and restarts every time after I manually kill it. I have no desktop environment installed (gnome, kde), so this app just uses memory and CPU for nothing.

What can I do? I couldn't find any initscript or something like that that runs it.

The following processes are causing it to appear: /usr/bin/Xorg : 0 -br -audit 0 -auth /var/gdm/:0.Xauth -nolisten tcp vt7

/usr/libexec/gdmgreeter

Removing the full graphical frontend is a better solution (x11?).

Thanks!