Always reallocate a new memory chunk when changing the gateway of a

route entry.

This makes sure we pass the correct size to free(9).

Reproted by and ok dlg@

diff --git a/sys/net/route.c b/sys/net/route.c
index 8a5cbd6..30c8def 100644 (file)
--- a/sys/net/route.c
+++ b/sys/net/route.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: route.c,v 1.372 2018/02/20 12:43:03 mpi Exp $ */
+/*     $OpenBSD: route.c,v 1.373 2018/02/22 08:47:20 mpi Exp $ */
 /*     $NetBSD: route.c,v 1.14 1996/02/13 22:00:46 christos Exp $      */
 
 /*
@@ -1004,11 +1004,14 @@ rt_setgate(struct rtentry *rt, struct sockaddr *gate, u_int rtableid)
        int glen = ROUNDUP(gate->sa_len);
        struct sockaddr *sa;
 
-       if (rt->rt_gateway == NULL || glen > ROUNDUP(rt->rt_gateway->sa_len)) {
+       if (rt->rt_gateway == NULL || glen != ROUNDUP(rt->rt_gateway->sa_len)) {
                sa = malloc(glen, M_RTABLE, M_NOWAIT);
                if (sa == NULL)
                        return (ENOBUFS);
-               free(rt->rt_gateway, M_RTABLE, 0);
+               if (rt->rt_gateway != NULL) {
+                       free(rt->rt_gateway, M_RTABLE,
+                           ROUNDUP(rt->rt_gateway->sa_len));
+               }
                rt->rt_gateway = sa;
        }
        memmove(rt->rt_gateway, gate, glen);