Avoid overflow by writing x = (y * 7) / 8 as x = y - (y / 8); ok florian

diff --git a/sbin/dhcpleased/engine.c b/sbin/dhcpleased/engine.c
index 7fda133..a98dc3d 100644 (file)
--- a/sbin/dhcpleased/engine.c
+++ b/sbin/dhcpleased/engine.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: engine.c,v 1.10 2021/03/16 17:40:28 florian Exp $     */
+/*     $OpenBSD: engine.c,v 1.11 2021/03/22 15:34:07 otto Exp $        */
 
 /*
  * Copyright (c) 2017, 2021 Florian Obser <florian@openbsd.org>
@@ -975,7 +975,7 @@ parse_dhcp(struct dhcpleased_iface *iface, struct imsg_dhcp *dhcp)
                if(renewal_time == 0)
                        renewal_time = lease_time / 2;
                if (rebinding_time == 0)
-                       rebinding_time = (lease_time * 7) / 8;
+                       rebinding_time = lease_time - (lease_time / 8);
 
                if (renewal_time >= rebinding_time) {
                        log_warnx("%s: renewal_time >= rebinding_time "