make ifindex2ifnet growing code more correct. (found by iij seil team)

1 files changed, 7 insertions, 4 deletions

diff --git a/sys/net/if.c b/sys/net/if.c
index ba44bcec1aa..451d530d1da 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if.c,v 1.70 2003/08/27 00:33:34 henric Exp $	*/
+/*	$OpenBSD: if.c,v 1.71 2003/10/01 05:06:06 itojun Exp $	*/
 /*	$NetBSD: if.c,v 1.35 1996/05/07 05:26:04 thorpej Exp $	*/
 
 /*
@@ -160,28 +160,31 @@ if_attachsetup(ifp)
 	 *	struct ifnet **ifindex2ifnet
 	 */
 	if (ifnet_addrs == 0 || ifindex2ifnet == 0 || if_index >= if_indexlim) {
-		size_t n;
+		size_t m, n, oldlim;
 		caddr_t q;
 		
+		oldlim = if_indexlim;
 		while (if_index >= if_indexlim)
 			if_indexlim <<= 1;
 
 		/* grow ifnet_addrs */
+		m = oldlim * sizeof(ifa);
 		n = if_indexlim * sizeof(ifa);
 		q = (caddr_t)malloc(n, M_IFADDR, M_WAITOK);
 		bzero(q, n);
 		if (ifnet_addrs) {
-			bcopy((caddr_t)ifnet_addrs, q, n/2);
+			bcopy((caddr_t)ifnet_addrs, q, m);
 			free((caddr_t)ifnet_addrs, M_IFADDR);
 		}
 		ifnet_addrs = (struct ifaddr **)q;
 
 		/* grow ifindex2ifnet */
+		m = oldlim * sizeof(struct ifnet *);
 		n = if_indexlim * sizeof(struct ifnet *);
 		q = (caddr_t)malloc(n, M_IFADDR, M_WAITOK);
 		bzero(q, n);
 		if (ifindex2ifnet) {
-			bcopy((caddr_t)ifindex2ifnet, q, n/2);
+			bcopy((caddr_t)ifindex2ifnet, q, m);
 			free((caddr_t)ifindex2ifnet, M_IFADDR);
 		}
 		ifindex2ifnet = (struct ifnet **)q;