Be paranoid about non-zero netmasks being associated with INET addresses

of 0.0.0.0.

The OpenBSD PF_ROUTE/NET_RT_DUMP sysctl is sending back routes with
RTAX_NETMASK set, but the corresponding sockaddr being 4 zero bytes
(with an address family of zero).  ppp was getting confused by this
and ending up interpreting it as a 0.0.0.0/32 routing table
destination and subsequently failing to do anything with the route.

Specifically, after this fix, ppp under OpenBSD can successfully
change and delete the default route again !

2 files changed, 20 insertions, 5 deletions

diff --git a/usr.sbin/ppp/ncpaddr.c b/usr.sbin/ppp/ncpaddr.c
index aa99bda..943db3d 100644
--- a/usr.sbin/ppp/ncpaddr.c
+++ b/usr.sbin/ppp/ncpaddr.c
@@ -591,8 +591,13 @@ ncprange_sethost(struct ncprange *range, const struct ncpaddr *from)
   case AF_INET:
     range->ncprange_family = AF_INET;
     range->ncprange_ip4addr = from->ncpaddr_ip4addr;
-    range->ncprange_ip4mask.s_addr = INADDR_BROADCAST;
-    range->ncprange_ip4width = 32;
+    if (from->ncpaddr_ip4addr.s_addr == INADDR_ANY) {
+      range->ncprange_ip4mask.s_addr = INADDR_ANY;
+      range->ncprange_ip4width = 0;
+    } else {
+      range->ncprange_ip4mask.s_addr = INADDR_BROADCAST;
+      range->ncprange_ip4width = 32;
+    }
     break;
 
 #ifndef NOINET6
@@ -654,8 +659,13 @@ ncprange_setip4host(struct ncprange *range, struct in_addr from)
 {
   range->ncprange_family = AF_INET;
   range->ncprange_ip4addr = from;
-  range->ncprange_ip4mask.s_addr = INADDR_BROADCAST;
-  range->ncprange_ip4width = 32;
+  if (from.s_addr == INADDR_ANY) {
+    range->ncprange_ip4mask.s_addr = INADDR_ANY;
+    range->ncprange_ip4width = 0;
+  } else {
+    range->ncprange_ip4mask.s_addr = INADDR_BROADCAST;
+    range->ncprange_ip4width = 32;
+  }
 }
 
 void
@@ -693,7 +703,10 @@ ncprange_setsa(struct ncprange *range, const struct sockaddr *host,
   case AF_INET:
     range->ncprange_family = AF_INET;
     range->ncprange_ip4addr = host4->sin_addr;
-    if (mask4) {
+    if (host4->sin_addr.s_addr == INADDR_ANY) {
+      range->ncprange_ip4mask.s_addr = INADDR_ANY;
+      range->ncprange_ip4width = 0;
+    } else if (mask4 && mask4->sin_family == AF_INET) {
       range->ncprange_ip4mask.s_addr = mask4->sin_addr.s_addr;
       range->ncprange_ip4width = mask42bits(mask4->sin_addr);
     } else {
diff --git a/usr.sbin/ppp/route.c b/usr.sbin/ppp/route.c
index 2ff5ee3..76ae24e 100644
--- a/usr.sbin/ppp/route.c
+++ b/usr.sbin/ppp/route.c
@@ -317,6 +317,8 @@ route_ParseHdr(struct rt_msghdr *rtm, struct sockaddr *sa[RTAX_MAX])
     if (rtm->rtm_addrs & (1 << rtax)) {
       sa[rtax] = (struct sockaddr *)wp;
       wp += ROUNDUP(sa[rtax]->sa_len);
+      if (sa[rtax]->sa_family == 0)
+        sa[rtax] = NULL;	/* ??? */
     } else
       sa[rtax] = NULL;
 }