Fix "route add 0.0.0.0/0 <gateway>" to work properly. Shift count

beyonds the integer width results undefined behavior in C spec.
Actually the count is masked by 0x1f on amd64.  Found by asou at
soum.co.jp

ok claudio kn schwarze

diff --git a/sbin/route/route.c b/sbin/route/route.c
index 8f18e27..e255fd6 100644 (file)
--- a/sbin/route/route.c
+++ b/sbin/route/route.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: route.c,v 1.224 2018/08/09 19:48:44 schwarze Exp $    */
+/*     $OpenBSD: route.c,v 1.225 2018/08/30 01:32:53 yasuoka Exp $     */
 /*     $NetBSD: route.c,v 1.16 1996/04/15 18:27:05 cgd Exp $   */
 
 /*
@@ -763,10 +763,14 @@ inet_makenetandmask(u_int32_t net, struct sockaddr_in *sin, int bits)
        char *cp;
 
        rtm_addrs |= RTA_NETMASK;
-       if (bits == 0 && net != 0)
-               bits = 32;
-       mask = 0xffffffff << (32 - bits);
-       net &= mask;
+       if (bits == 0 && net == 0)
+               mask = 0;
+       else {
+               if (bits == 0)
+                       bits = 32;
+               mask = 0xffffffff << (32 - bits);
+               net &= mask;
+       }
        sin->sin_addr.s_addr = htonl(net);
        sin = &so_mask.sin;
        sin->sin_addr.s_addr = htonl(mask);