coap_split_uri: Check if port number is in valid range

This change is made to resolve the failed URI parser test
t_parse_uri5()

src/uri.c

@@ -133,6 +133,12 @@ coap_split_uri(unsigned char *str_var, size_t len, coap_uri_t *uri) {
       while (p < q)
 	uri_port = uri_port * 10 + (*p++ - '0');
 
+      /* check if port number is in allowed range */
+      if (uri_port > 65535) {
+	res = -4;
+	goto error;
+      }
+
       uri->port = uri_port;
     } 
   }