As reported in bug #3029, it is not possible to log in as a
user with empty password.

Furthermore, the error message printed in this case is
incorrect.  PAM_pwdb uses the function pwdb_strerror() to
format the error message, but the error code is a PAM code,
not a PWDB code, so the correct function is pam_strerror().

I suggest the following patch:

*** support.-c~ Thu Apr  8 03:19:52 1999
--- support.-c  Mon Jul 26 17:14:17 1999
***************
*** 464,470 ****
            retval = pwdb_run_helper_binary(pamh, p);
        } else {
            retval = PAM_AUTHINFO_UNAVAIL;
!           _log_err(LOG_ALERT, "get passwd; %s",
pwdb_strerror(retval));
        }
        (void) pwdb_delete(&pw);
        p = NULL;
--- 464,470 ----
            retval = pwdb_run_helper_binary(pamh, p);
        } else {
            retval = PAM_AUTHINFO_UNAVAIL;
!           _log_err(LOG_ALERT, "get passwd; %s",
pam_strerror(pamh, retval));
        }
        (void) pwdb_delete(&pw);
        p = NULL;