lua: more fixes

Author: rsmarples

src/plugins/lua.c

@@ -286,6 +286,18 @@ lua_run_lookup_addr(struct plugin *p, struct srv_ctx *sctx, const void *data,
 	size_t hostname_len;
 	char hostname[DHCP_HOSTNAME_LEN];
 	char chaddr[sizeof(((struct bootp *)0)->chaddr) * 3];
+	struct sockaddr_in sin = {
+		.sin_family = AF_INET,
+#ifdef BSD
+		.sin_len = sizeof(sin),
+#endif
+	};
+	struct sockaddr *sa = (struct sockaddr *)&sin;
+	uint32_t ltime = 0;
+	struct iovec iov[] = {
+		{ .iov_base = &ltime, .iov_len = sizeof(ltime) },
+		{ .iov_base = &sin, .iov_len = sizeof(sin) },
+	};
 
 	if (len < sizeof(hostname_len)) {
 		errno = EINVAL;
@@ -295,31 +307,26 @@ lua_run_lookup_addr(struct plugin *p, struct srv_ctx *sctx, const void *data,
 	datap += sizeof(hostname_len);
 	len -= sizeof(hostname_len);
 
-	if (len < hostname_len) {
+	if (hostname_len != 0) {
+		if (len < hostname_len) {
+			errno = EINVAL;
+			goto out;
+		}
+		memcpy(hostname, datap, hostname_len);
+		datap += hostname_len;
+		len -= hostname_len;
+	} else
+		hostname[0] = '\0';
+
+	if (len < sizeof(*l->l_req)) {
 		errno = EINVAL;
 		goto out;
 	}
-	memcpy(hostname, datap, hostname_len);
-	datap += hostname_len;
-	len -= hostname_len;
-
 	/* Aligns bootp */
 	memmove(UNCONST(data), datap, len);
 
 	l->l_req = data;
 	l->l_reqlen = len;
-	struct sockaddr_in sin = {
-		.sin_family = AF_INET,
-#ifdef BSD
-		.sin_len = sizeof(sin),
-#endif
-	};
-	struct sockaddr *sa = (struct sockaddr *)&sin;
-	uint32_t ltime = 0;
-	struct iovec iov[] = {
-		{ .iov_base = &ltime, .iov_len = sizeof(ltime) },
-		{ .iov_base = &sin, .iov_len = sizeof(sin) },
-	};
 
 	lua_pop(L, lua_gettop(L));