send CSRF token in a response header,

update the page's CSRF tokens with the new token
from the response header,
verify csrf token in ajax endpoints,
initialize a session for every endpoint

ajax/bandwidth/get_bandwidth.php

@@ -1,8 +1,10 @@
 <?php
+
+require('includes/csrf.php');
+
 require_once '../../includes/config.php';
 require_once RASPI_CONFIG.'/raspap.php';
 
-session_start();
 header('X-Frame-Options: DENY');
 header("Content-Security-Policy: default-src 'none'; connect-src 'self'");
 require_once '../../includes/authenticate.php';

ajax/bandwidth/get_bandwidth_hourly.php

@@ -1,4 +1,7 @@
 <?php 
+
+require('includes/csrf.php');
+
 if (filter_input(INPUT_GET, 'tu') == 'h') {
 
 	header('X-Content-Type-Options: nosniff');

ajax/networking/gen_int_config.php

@@ -1,5 +1,7 @@
 <?php
-session_start();
+
+require('includes/csrf.php');
+
 include_once('../../includes/config.php');
 include_once('../../includes/functions.php');
 

ajax/networking/get_all_interfaces.php

@@ -1,4 +1,7 @@
 <?php
+
+    require('includes/csrf.php');
+
     exec("ls /sys/class/net | grep -v lo", $interfaces);
     echo json_encode($interfaces);
 ?>

ajax/networking/get_int_config.php

@@ -1,5 +1,7 @@
 <?php
-session_start();
+
+require('includes/csrf.php');
+
 include_once('../../includes/config.php');
 include_once('../../includes/functions.php');
 

ajax/networking/get_ip_summary.php

@@ -1,5 +1,7 @@
 <?php
-session_start();
+
+require('includes/csrf.php');
+
 include_once('../../includes/functions.php');
 
 if(isset($_POST['interface'])) {

ajax/networking/save_int_config.php

@@ -1,5 +1,7 @@
 <?php
-    session_start();
+
+    require('includes/csrf.php');
+
     include_once('../../includes/config.php');
     include_once('../../includes/functions.php');
     if(isset($_POST['interface'])) {

includes/csrf.php

@@ -0,0 +1,11 @@
+<?php
+
+include_once('includes/functions.php');
+include_once('includes/session.php');
+
+if (csrfValidateRequest() && !CSRFValidate()) {
+  handleInvalidCSRFToken();
+}
+
+ensureCSRFSessionToken();
+header('X-CSRF-Token', $_SESSION['csrf_token']);

includes/session.php

@@ -0,0 +1,5 @@
+<?php
+
+if (session_status() == PHP_SESSION_NONE) {
+  session_start();
+}

index.php

@@ -18,7 +18,7 @@
  * @see        http://sirlagz.net/2013/02/08/raspap-webgui/
  */
 
-session_start();
+require('includes/csrf.php');
 
 include_once('includes/config.php');
 include_once(RASPI_CONFIG.'/raspap.php');
@@ -39,12 +39,6 @@ include_once('includes/about.php');
 $output = $return = 0;
 $page = $_GET['page'];
 
-if (csrfValidateRequest() && !CSRFValidate()) {
-  handleInvalidCSRFToken();
-}
-
-ensureCSRFSessionToken();
-
 if (!isset($_COOKIE['theme'])) {
     $theme = "custom.css";
 } else {

js/custom.js

@@ -160,13 +160,22 @@ function setupBtns() {
     });
 }
 
+function updateCSRFToken(xhr, settings) {
+    var newToken = xhr.getResponseHeader("X-CSRF-Token");
+    if (newToken) {
+        $('meta[name=csrf_token]').attr('content', newToken);
+        $('[name=csrf_token]:input').attr('value', newToken);
+    }
+}
+
 $.ajaxSetup({
     beforeSend: function(xhr, settings) {
         var csrfToken = $('meta[name=csrf_token]').attr('content');
         if (/^(POST|PATCH|PUT|DELETE)$/i.test(settings.type)) {
             xhr.setRequestHeader("X-CSRF-Token", csrfToken);
         }
-    }
+    },
+    ajaxComplete: updateCSRFToken
 });
 
 $().ready(function(){