From 854c26a2a30cbba2cb9b734662aaf41876a42556 Mon Sep 17 00:00:00 2001
From: Kenji ITO <mystralkk@gmail.com>
Date: Thu, 23 Nov 2017 20:41:43 +0900
Subject: [PATCH] Added another security check to cached files

---
 system/classes/Cache/FileSystem.php | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/system/classes/Cache/FileSystem.php b/system/classes/Cache/FileSystem.php
index bb6f61d61..3031c5967 100644
--- a/system/classes/Cache/FileSystem.php
+++ b/system/classes/Cache/FileSystem.php
@@ -11,6 +11,8 @@
  */
 class FileSystem implements CacheInterface
 {
+    const SECURITY_HEADER = "<?php if (!defined('VERSION')) { die('This file cannot be used on its own!'); } ?>\n";
+
     /**
      * @var string
      */
@@ -120,6 +122,8 @@ public function get($key, $defaultValue = null)
             return $defaultValue;
         }
 
+        // Remove security header
+        $temp = str_replace(self::SECURITY_HEADER, '', $temp);
         $data = @unserialize($temp);
 
         if ($data === false) {
@@ -157,8 +161,9 @@ public function set($key, $data, $ttl = 0)
             'ttl'     => (int) $ttl,
             'hash'    => $this->getHash($data),
         );
+        $serialized = self::SECURITY_HEADER . serialize($item);
 
-        return (@file_put_contents($fileName, serialize($item)) !== false);
+        return (@file_put_contents($fileName, $serialized) !== false);
     }
 
     /**