From 0f4e009215bfa3136d334fa557335266637a7585 Mon Sep 17 00:00:00 2001
From: Christopher Smith <chris@jalakai.co.uk>
Date: Wed, 20 Mar 2013 00:06:07 +0000
Subject: add a token to fetch urls requiring image resize/crop to prevent
 external DDOS via fetch

---
 lib/exe/fetch.php | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

(limited to 'lib/exe/fetch.php')

diff --git a/lib/exe/fetch.php b/lib/exe/fetch.php
index a558a3db8..48aa22fe2 100644
--- a/lib/exe/fetch.php
+++ b/lib/exe/fetch.php
@@ -32,7 +32,7 @@ if(!defined('SIMPLE_TEST')) {
     }
 
     // check for permissions, preconditions and cache external files
-    list($STATUS, $STATUSMESSAGE) = checkFileStatus($MEDIA, $FILE, $REV);
+    list($STATUS, $STATUSMESSAGE) = checkFileStatus($MEDIA, $FILE, $REV, $WIDTH, $HEIGHT);
 
     // prepare data for plugin events
     $data = array(
@@ -180,7 +180,7 @@ function sendFile($file, $mime, $dl, $cache, $public = false) {
  * @param $file  reference to the file variable
  * @returns array(STATUS, STATUSMESSAGE)
  */
-function checkFileStatus(&$media, &$file, $rev = '') {
+function checkFileStatus(&$media, &$file, $rev = '', $width=0, $height=0) {
     global $MIME, $EXT, $CACHE, $INPUT;
 
     //media to local file
@@ -200,6 +200,10 @@ function checkFileStatus(&$media, &$file, $rev = '') {
         if(empty($media)) {
             return array(400, 'Bad request');
         }
+        // check token for resized images
+        if (($width || $height) && media_get_token($media, $width, $height) !== $INPUT->str('tok')) {
+            return array(412, 'Precondition Failed');
+        }
 
         //check permissions (namespace only)
         if(auth_quickaclcheck(getNS($media).':X') < AUTH_READ) {
-- 
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