GDM asks for password twice during login

[Brian Croom]

Binary package hint: gdm

Running the latest Intrepid packages (gdm=2.20.7-0ubuntu4, GDM always displays the password prompt twice after I enter a username. The progression is: username->password->password->logged in. The string entered for the first password prompt seems to be ignored altogether. I can input my actual password, a different string, or a null string with no effect; the second password prompt behaves as expected.

- This behavior is the same regardless of the current GDM theme
- Logging into virtual terminals works as expected

[Sebastien Bacher (seb128)]

thank you for your bug report, you seem to be the only one to have the issue, did you start getting it after an upgrade or a configuration change, do you anything specific to your configuration?

[Brian Croom (aikoniv)]

I have been running Intrepid since Alpha 1 and keep the system up to date. This first started occurring several weeks ago, I neglected to report it then, assuming it was a wider-spread issue and would be quickly resolved. Unfortunately that means that I have no leads on what specific update caused the problem.

I'm not aware of having made any config changes, and I just tried reinstalling a number of packages to try to restore default configs, but there was no change.

Any ideas for further debugging?

[Sebastien Bacher (seb128)]

no real idea for debugging no, do you have anything in the auth.log, message and syslog log?

[Peter Adamka (malmo)]

I got same isuue.
Real problem is not the GDM, but changes in pam.d as any application, which required authentication, requested entering password twice.

Sollution is to add in /etc/pam.d/common-auth clausule 'try_first_pass':
auth requisite pam_unix.so nullok_secure try_first_pass

I'm not sure, which package messed it up.

[Sebastien Bacher (seb128)]

reassigning to pam that doesn't look like a gdm issue, Steve do you have any idea about that one?

[Steve Langasek (vorlon)]

Peter, Brian, please post the contents of your /etc/pam.d/common-auth files when this error happens.

[Brian Croom (aikoniv)]

Sorry for the late reply,

Firstly, I'm not sure I'm seeing the same thing as Peter. I haven't had any other application ask for the password twice (e.g. any of the 'unlock' buttons in GNOME, or gksu[do]).

Secondly, here are the non-comment lines from my /etc/pam.d/common-auth:

auth [success=1 default=ignore] pam_unix.so nullok_secure
auth requisite pam_deny.so
auth required pam_permit.so
auth optional pam_smbpass.so migrate

[Steve Langasek (vorlon)]

Hi Brian,

There is only one module listed here in your common-auth file that will prompt for a password. Do you have other password-prompting modules configured directly in /etc/pam.d/gdm?

[Brian Croom (aikoniv)]

Ah, figured it out. Turns out a 3rd party package (not in the Ubuntu repos) had added a line for its own PAM module into the configuration, but with incorrect arguments. Now that's cleared up and things are working normally.

And now I have a clue about how PAM works, yay!