Index: dispatch.c
===================================================================
RCS file: /cvs/src/usr.sbin/dhcpd/dispatch.c,v
retrieving revision 1.43
diff -u -p -r1.43 dispatch.c
--- dispatch.c	12 Apr 2017 19:17:30 -0000	1.43
+++ dispatch.c	15 Nov 2021 03:50:46 -0000
@@ -47,6 +47,7 @@
 #include <net/if.h>
 #include <net/if_dl.h>
 #include <net/if_media.h>
+#include <net/if_types.h>
 
 #include <netinet/in.h>
 
@@ -112,14 +113,10 @@ discover_interfaces(int *rdomain)
 	for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
 		/*
 		 * See if this is the sort of interface we want to
-		 * deal with.  Skip loopback, point-to-point and down
-		 * interfaces, except don't skip down interfaces if we're
-		 * trying to get a list of configurable interfaces.
+		 * deal with, which is basically Ethernet.
 		 */
 		if ((ifa->ifa_flags & IFF_LOOPBACK) ||
-		    (ifa->ifa_flags & IFF_POINTOPOINT) ||
-		    (!(ifa->ifa_flags & IFF_UP)) ||
-		    (!(ifa->ifa_flags & IFF_BROADCAST)))
+		    (ifa->ifa_flags & IFF_POINTOPOINT))
 			continue;
 
 		/* See if we've seen an interface that matches this one. */
@@ -156,11 +153,27 @@ discover_interfaces(int *rdomain)
 		/* If we have the capability, extract link information
 		   and record it in a linked list. */
 		if (ifa->ifa_addr->sa_family == AF_LINK) {
-			struct sockaddr_dl *sdl =
-			    ((struct sockaddr_dl *)(ifa->ifa_addr));
+			struct if_data *ifi;
+			struct sockaddr_dl *sdl;
+
+			ifi = (struct if_data *)ifa->ifa_data;
+			if (ifi->ifi_type != IFT_ETHER &&
+			    ifi->ifi_type != IFT_CARP) {
+				/* this interface will be cleaned up later */
+				continue;
+			}
+
+			sdl = ((struct sockaddr_dl *)(ifa->ifa_addr));
+			if (sdl->sdl_alen > sizeof(tmp->hw_address.haddr)) {
+				log_warnx("interface %s long hardware address",
+				    tmp->name);
+				/* this interface will be cleaned up later */
+				continue;
+			}
+
 			tmp->index = sdl->sdl_index;
 			tmp->hw_address.hlen = sdl->sdl_alen;
-			tmp->hw_address.htype = HTYPE_ETHER; /* XXX */
+			tmp->hw_address.htype = HTYPE_ETHER;
 			memcpy(tmp->hw_address.haddr,
 			    LLADDR(sdl), sdl->sdl_alen);
 		} else if (ifa->ifa_addr->sa_family == AF_INET) {
@@ -236,6 +249,17 @@ discover_interfaces(int *rdomain)
 	last = NULL;
 	for (tmp = interfaces; tmp; tmp = next) {
 		next = tmp->next;
+
+		if (tmp->index == 0) {
+			log_warnx("Can't listen on %s - wrong interface type",
+			    tmp->name);
+			/* Remove tmp from the list of interfaces. */
+			if (!last)
+				interfaces = interfaces->next;
+			else
+				last->next = tmp->next;
+			continue;
+		}
 
 		if (!tmp->ifp) {
 			log_warnx("Can't listen on %s - it has no IP address.",