pam_canonicalize_user.so
This PAM module uses the name of the user obtained via pam_get_user(3) as a key to query the password database, and replaces PAM_USER with the pw_name value that has been returned.
The user name was set successfully.
The user was not found.
The application did not supply neither a user name nor a conversation method.
The conversation method supplied by the application is waiting for an event.
The conversation method supplied by the application failed to obtain the user name.
Error resuming an old conversation.
Memory buffer error.
Prepend the PAM auth stack with the following line to canonicalize the user name before the authentication:
auth required pam_canonicalize_user.so