Index: lib/ipmi_user.c
===================================================================
RCS file: /cvsroot/ipmitool/ipmitool/lib/ipmi_user.c,v
retrieving revision 1.23
diff -u -r1.23 ipmi_user.c
--- lib/ipmi_user.c	7 Feb 2012 13:14:12 -0000	1.23
+++ lib/ipmi_user.c	17 Apr 2012 19:41:40 -0000
@@ -727,7 +727,7 @@
 				print_user_usage();
 				return -1;
 			}
-			if (str2uchar(argv[2], &user_id) != 0)
+			if (str2uchar(argv[2], &user_id) != 0 || user_id == 0)
 			{
 				lprintf(LOG_ERR, "Invalid user ID: %s", argv[2]);
 				return (-1);