diff -r 2b7e90a4d3ce libpam/pam_google_authenticator.c
--- a/libpam/pam_google_authenticator.c	Wed Feb 23 16:29:42 2011 -0800
+++ b/libpam/pam_google_authenticator.c	Mon Feb 28 16:22:32 2011 +0000
@@ -568,6 +568,15 @@
     // If nothing matched, display an error message
     if (rc != PAM_SUCCESS) {
       log_message(LOG_ERR, pamh, "Invalid verification code");
+      rc = PAM_PERM_DENIED;
+    }
+  } else {
+    if (username) {
+      if (fd<0) {
+      	rc = PAM_CRED_UNAVAIL;
+      } else if (buf==NULL || secret==NULL) {
+        rc = PAM_AUTHTOK_ERR;
+      }
     }
   }