A note on GDM

[Haukur Hreinsson <hawk gagarin is>]

I have a Debian system and am using shadow passwords. GDM would fail to
authenticate me, sending this to syslog:

Mar  6 15:16:09 celine gdm[20988]: gdm_config_parse: Invalid server line
in config file. Ignoring!
Mar  6 15:16:10 celine gdm[20989]: gdm_auth_secure_display: Could not
unlink /opt/gnome/var/gdm/:0.xauth file: No such file or directory
Mar  6 15:16:13 celine gdmgreeter[20996]: No default session link found.
Using Xsession. 
Mar  6 15:16:20 celine gdm[20993]: PAM unable to
dlopen(/lib/security/pam_pwdb.so)
Mar  6 15:16:20 celine gdm[20993]: PAM [dlerror:
/lib/security/pam_pwdb.so: cannot open shared object file: No such file
or directory]
Mar  6 15:16:20 celine gdm[20993]: PAM adding faulty module:
/lib/security/pam_pwdb.so
Mar  6 15:16:20 celine gdm[20993]: PAM unable to
dlopen(/lib/security/pam_cracklib.so)
Mar  6 15:16:20 celine gdm[20993]: PAM [dlerror:
/lib/security/pam_cracklib.so: cannot open shared object file: No such
file or directory]
Mar  6 15:16:20 celine gdm[20993]: PAM adding faulty module:
/lib/security/pam_cracklib.so
Mar  6 15:16:21 celine gdm[20993]: Couldn't authenticate hawk

I had some PAM stuff installed at the time, but not some parts that gdm
obviously needs. I installed the Debian packages libpam-pwdb and
libpam-cracklib and all was well. Perhaps this will help those other
people who've been having trouble getting gdm to authenticate them.