Red Hat Bugzilla – Bug 1315342
XDMCP gnome session unlock screen fails
Last modified: 2018-03-06 04:40:30 EST
Created attachment 1133788 [details]
journalctl output of gdm with debuglevel
Description of problem:
remote xdmcp session can't unlock the screen
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. install gnome desktop (yum install gnome-desktop)
2. add tcp listener to gdm by adding DisallowTCP=false to /etc/gdm/custom.conf
3. restart gdm (systemctl restart gdm.service)
4. access machine using xdmcp (on a linux workstation: Xephyr :1 -ac -br -screen 1024x768 -reset -terminate -query server.example.com)
5. log into gdm (using the gnome classic session)
6. see gnome desktop, so far so good.
7. lock the remote screen using the system menu in the top right corner of the gnome shell, lock icon (or wait till the automatic lock kicks in)
8. the gnome curtain displays.
9. hit enter, password prompt shows
10. enter password. Password prompt shows again. no error message.
can't unlock a remote gnome lock screen.
unlock and desktop shows again.
Unlocking the session using loginctl works.
A locally (as in sitting in front of the servers keyboard) logged in user can lock and unlock the screen.
Running gdm with debug enabled here is a shortened version of journalctl, a longer version is attached
gdm: GdmSessionWorker: state AUTHENTICATED
gdm: GdmSessionWorker: state AUTHORIZED
gdm: GdmSessionWorker: state ACCREDITED
gdm: GdmCommon: process (pid:18514) done (status:0)
gdm: GdmSession: Emitting 'reauthenticated' signal
gdm: GLib: g_variant_new_string: assertion 'string != NULL' failed
gdm: GdmManager: logind 'ActivateSessionOnSeat' org.freedesktop.login1.NoSuchSeat raised:
gdm: GDBus.Error:org.freedesktop.login1.NoSuchSeat: No seat '[Invalid UTF-8]' known
gdm: GdmManager: unable to activate session: 26
The glib error and the invalid utf8 look suspicious.
Created attachment 1186452 [details]
don't try to change vts on an xdmcp session
Following the steps in the description I was able to successfully log in/out/in of a XDMCP gnome session on gdm-3.14.2-18.el7.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.