Bugfix/freemodbus fix dereferencing to freed element issue

freemodbus/common/esp_modbus_slave.c

@@ -69,7 +69,7 @@ static void mbc_slave_free_descriptors(void) {
     mb_slave_options_t* mbs_opts = &slave_interface_ptr->opts;
 
     for (int descr_type = 0; descr_type < MB_PARAM_COUNT; descr_type++) {
-        for (it = LIST_FIRST(&mbs_opts->mbs_area_descriptors[descr_type]); it != NULL; it = LIST_NEXT(it, entries)) {
+        while ((it = LIST_FIRST(&mbs_opts->mbs_area_descriptors[descr_type]))) {
             LIST_REMOVE(it, entries);
             free(it);
         }

freemodbus/tcp_slave/port/port_tcp_slave.c

@@ -205,6 +205,10 @@ static int xMBTCPPortAcceptConnection(int xListenSockId, char** pcIPAddr)
             inet6_ntoa_r(((struct sockaddr_in6 *)&xSrcAddr)->sin6_addr, cAddrStr, sizeof(cAddrStr) - 1);
         }
 #endif
+        else {
+            // Make sure ss_family is valid
+            abort();
+        }
         ESP_LOGI(TAG, "Socket (#%d), accept client connection from address: %s", xSockId, cAddrStr);
         pcStr = calloc(1, strlen(cAddrStr) + 1);
         if (pcStr && pcIPAddr) {