Updated gdm packages that fix several bugs are now available for Red Hat Enterprise Linux 6.
The GNOME Display Manager (GDM) provides the graphical login screen, shown shortly after boot up, log out, and when user-switching.
- Logging into the system with GNOME installed while having set KDE Display Manager (KDM) as the default display manager could sometimes cause the user-switch applet to abort. Consequently, switching the user was impossible unless the applet was reloaded. The underlying code has been modified to prevent interference of multiple queued loads of user information so the user-switch applet is now more resilient to crash in this scenario.
- GDM previously did not forward X Display Manager Control Protocol (XDMCP) indirect queries to the correct port of the appropriate machine. Consequently, the GDM host chooser did not work correctly and XDMCP connection could not be established. With this update, GDM now uses the correct port when redirecting XCDMCP queries and XDMCP connections can be established with the chosen remote host as expected.
- BZ#785775, BZ#865832
- Previously, GDM displayed login messages for an insufficiently short period of time so that some users were not able to read the messages. This update increases the duration of the time period for which is a message displayed at login time to a minimum of 3 seconds.
- GDM previously did not consult content of the "~/.dmrc" file before reading the cached copy of the drmc file in the "/var/cache/gdm/$USERNAME/" directory. This behavior could lead to incorrect or inconsistent users environment settings, such as the default graphical desktop session or language, in environments using network-mounted home directories. This happened because changes to "~/.dmrc" had no effect on machines to which the users logged in and out before modifying the "~/.dmrc" file. With this update, GDM reads "~/.dmrc" before "/var/cache/gdm/$USERNAME/dmrc" so that updates to the user's environment configuration can take effect.
- When the user switched to the already active session, GDM attempted to clean up temporary internal resources twice. This resulted in spurious error messages being logged in the system log. The underlying code has been fixed so that GDM now cleans up those resources correctly.
- When the PreSession shell script fails, the user is expected to be denied login to the system. GDM previously ignored PreSession failures so that the users were able to proceed with an unauthorized login to the system. This update corrects this behavior so that GDM now fails the login process upon the PreSession script failure.
- GDM adjusted the width of the login window in accordance with the length of the authentication message. If an authentication message was very long, the login window became unreasonably wide, resulting in text being displayed out of the visible screen. With this update, long authentication messages are automatically wrapped so the login window retains the expected size, and the message is displayed properly.
- When the user logged out of the system or switched runlevel, the gdm-smartcard-worker extension was terminated unexpectedly with a segmentation fault. This update modifies GDM to ensure that gdm-smartcard-worker is brought down gracefully.
- The GDM default greeter did not set the LANG environment variable in canonical form. Consequently, in mixed environment deployments, such as networks containing Mac OS X machines, the LANG encoding was not correctly recognized by non-Linux systems. This update ensures that GDM sets environment variables are in canonical form.
- The gdm-smartcard-worker extension terminated unexpectedly with a segmentation fault upon startup if the system was started without smart card support. The respective code in gdm-smartcard-worker has been modified so this GDM extension no longer crashes in this scenario.
- When using the smart card authentication method with the "disable_user_list=True" option set, entering an incorrect PIN disabled all further smart card logins until the user successfully logged in using a different authentication method. This update properly resets the dialog window in this situation and allows users to repeat smart card authentication attempts.
- When booting to runlevel 5 on IBM S/390 systems, GDM emitted a warning messages about not being able to start the X server, which were harmless but could confuse the user. The underlying GDM code has been modified to no longer attempt to start the X server on IBM S/390 systems, and the messages are no longer logged to the system logs.
Users of gdm are advised to upgrade to these updated packages, which fix these bugs. GDM must be restarted for this update to take effect. Rebooting achieves this, but changing the runlevel from 5 to 3 and back to 5 also restarts GDM.