(legacy) regression services_upnp.php

(cherry picked from commit 1ffc2f54)

src/www/services_upnp.php

@@ -83,6 +83,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
     if (!empty($pconfig['enable']) && (empty($pconfig['enable_upnp']) && empty($pconfig['enable_natpmp']))) {
         $input_errors[] = gettext('At least one of \'UPnP\' or \'NAT-PMP\' must be allowed');
     }
+    if (!empty($pconfig['iface_array'])) {
         foreach($pconfig['iface_array'] as $iface) {
             if ($iface == 'wan') {
                 $input_errors[] = gettext('It is a security risk to specify WAN in the \'Interface\' field');
@@ -90,6 +91,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
                 $input_errors[] = gettext('You cannot select the external interface as an internal interface.');
             }
         }
+    }
     if (!empty($pconfig['overridewanip']) && !is_ipaddr($pconfig['overridewanip'])) {
         $input_errors[] = gettext('You must specify a valid ip address in the \'Override WAN address\' field');
     }
@@ -225,12 +227,12 @@ include("head.inc");
                       <td><a id="help_for_iface_array" href="#" class="showhelp"><i class="fa fa-info-circle"></i></a> <?=gettext("Interfaces (generally LAN)");?></td>
                       <td>
                        <select class="selectpicker" name="iface_array[]" multiple="multiple">
-                         <option value="lo0" <?=in_array('lo0', $pconfig['iface_array']) ? "selected=\"selected\"" : "";?>>
+                         <option value="lo0" <?=!empty($pconfig['iface_array']) && in_array('lo0', $pconfig['iface_array']) ? "selected=\"selected\"" : "";?>>
                            <?=gettext("Localhost");?>
                          </option>
 <?php
                         foreach (get_configured_interface_with_descr() as $iface => $ifacename):?>
-                          <option value="<?=$iface;?>" <?=in_array($iface, $pconfig['iface_array']) ? "selected=\"selected\"" : "";?>>
+                          <option value="<?=$iface;?>" <?=!empty($pconfig['iface_array']) && in_array($iface, $pconfig['iface_array']) ? "selected=\"selected\"" : "";?>>
                             <?=htmlspecialchars($ifacename);?>
                           </option>
 <?php