Treat '' in SSIDs param of DBus Scan as a request for Broadcast scan.

wpa_supplicant/dbus/dbus_new_handlers.c

 /*
  * WPA Supplicant / dbus-based control interface
  * Copyright (c) 2006, Dan Williams <dcbw@redhat.com> and Red Hat, Inc.
  * Copyright (c) 2009-2010, Witold Sowa <witold.sowa@gmail.com>
  * Copyright (c) 2009, Jouni Malinen <j@w1.fi>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
@@ skipping 977 matching lines @@
                                    "call");
                         *reply = wpas_dbus_error_invalid_args(
                                 message, "Too many ssids specified. Specify "
                                 "at most four");
                         return -1;
                 }
 
                 dbus_message_iter_recurse(&array_iter, &sub_array_iter);
 
                 dbus_message_iter_get_fixed_array(&sub_array_iter, &val, &len);
-                if (len == 0) {
-                        dbus_message_iter_next(&array_iter);
-                        continue;
+
+                if (len != 0) {
+                        ssid = os_malloc(len);
+                        if (ssid == NULL) {
+                                wpa_printf(MSG_DEBUG,
+                                           "wpas_dbus_handler_scan[dbus]: "
+                                           "out of memory. Cannot allocate "
+                                           "memory for SSID");
+                                *reply = dbus_message_new_error(
+                                                message, DBUS_ERROR_NO_MEMORY,
+                                                NULL);
+                                return -1;
+                        }
+                        os_memcpy(ssid, val, len);
+                } else {
+                        /* Allow zero-length SSIDs */
+                        ssid = NULL;
                 }
 
-                ssid = os_malloc(len);
-                if (ssid == NULL) {
-                        wpa_printf(MSG_DEBUG, "wpas_dbus_handler_scan[dbus]: "
-                                   "out of memory. Cannot allocate memory for "
-                                   "SSID");
-                        *reply = dbus_message_new_error(
-                                message, DBUS_ERROR_NO_MEMORY, NULL);
-                        return -1;
-                }
-                os_memcpy(ssid, val, len);
                 ssids[ssids_num].ssid = ssid;
                 ssids[ssids_num].ssid_len = len;
 
                 dbus_message_iter_next(&array_iter);
                 ssids_num++;
         }
 
         params->num_ssids = ssids_num;
         return 0;
 }
@@ skipping 1987 matching lines @@
         dbus_message_iter_recurse(&iter, &variant_iter);
 
         reply = set_network_properties(message, net->wpa_s, ssid,
                                        &variant_iter);
         if (reply)
                 wpa_printf(MSG_DEBUG, "dbus control interface couldn't set "
                            "network properties");
 
         return reply;
 }