diff --git a/ChangeLog b/ChangeLog
index 68be0800..97a5e4ff 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -4,6 +4,8 @@
 	* src/login.c: Copy the name of the user authenticated by PAM to
 	username. This simplify later logging (avoid USE_PAM
 	conditional).
+	* src/login.c: Check that no username is specified with -r.
+	* src/login.c: Make sure a username is specified with -f.
 
 2008-09-20  Nicolas François  <nicolas.francois@centraliens.net>
 
diff --git a/src/login.c b/src/login.c
index 60964d3d..5d31df0c 100644
--- a/src/login.c
+++ b/src/login.c
@@ -339,6 +339,15 @@ static void process_flags (int argc, char *const *argv)
 		++optind;
 	}
 
+#ifdef	RLOGIN
+	if (rflg && (NULL != username)) {
+		usage ();
+	}
+#endif				/* RLOGIN */
+	if (fflg && (NULL == username)) {
+		usage ();
+	}
+
 }