Descrption: Check input argument
Author: Michael Meskes <meskes@debian.org>

--- bsdmainutils/usr.bin/ncal/ncal.c.orig	2020-08-04 14:11:01.299820849 +0200
+++ bsdmainutils/usr.bin/ncal/ncal.c	2020-08-04 14:12:15.812172154 +0200
@@ -425,7 +425,9 @@
 		break;
 	case 0:
 		if (flag_today != NULL) {
			y = strtol(flag_today, NULL, 10);
+			if (y < 1 || y > 9999)
+				errx(EX_USAGE, "year `%d' not in range 1..9999", y);
 			m = strtol(flag_today + 5, NULL, 10);
 		} else {
 			time_t t;