From c695136e4d75695178a9fc848a7cf6bfa2b9346c Mon Sep 17 00:00:00 2001
From: plegall <plg@piwigo.org>
Date: Fri, 19 Mar 2010 22:25:39 +0000
Subject: bug 1328: backport the pwg_token on trunk

bug 1329: backport the check_input_parameter on trunk

feature 1026: add pwg_token feature for edit/delete comment. Heavy refactoring
on this feature to make the code simpler and easier to maintain (I hope).

git-svn-id: http://piwigo.org/svn/trunk@5195 68402e56-0260-453c-a942-63ccdbb3a9ee
---
 include/functions.inc.php | 82 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)

(limited to 'include/functions.inc.php')

diff --git a/include/functions.inc.php b/include/functions.inc.php
index 91738090f..092fe15a4 100644
--- a/include/functions.inc.php
+++ b/include/functions.inc.php
@@ -1482,4 +1482,86 @@ function get_icon($date, $is_child_date = false)
 
   return $cache['get_icon'][$date] ? $icon : array();
 }
+
+/**
+ * check token comming from form posted or get params to prevent csrf attacks
+ * if pwg_token is empty action doesn't require token
+ * else pwg_token is compare to server token
+ *
+ * @return void access denied if token given is not equal to server token
+ */
+function check_pwg_token()
+{
+  $valid_token = get_pwg_token();
+  $given_token = null;
+
+  if (!empty($_POST['pwg_token']))
+  {
+    $given_token = $_POST['pwg_token'];
+  }
+  elseif (!empty($_GET['pwg_token']))
+  {
+    $given_token = $_GET['pwg_token'];
+  }
+  if ($given_token != $valid_token)
+  {
+    access_denied();
+  }
+}
+
+function get_pwg_token()
+{
+  global $conf;
+
+  return hash_hmac('md5', session_id(), $conf['secret_key']);
+}
+
+/*
+ * breaks the script execution if the given value doesn't match the given
+ * pattern. This should happen only during hacking attempts.
+ *
+ * @param string param_name
+ * @param array param_array
+ * @param boolean is_array
+ * @param string pattern
+ *
+ * @return void
+ */
+function check_input_parameter($param_name, $param_array, $is_array, $pattern)
+{
+  $param_value = null;
+  if (isset($param_array[$param_name]))
+  {
+    $param_value = $param_array[$param_name];
+  }
+
+  // it's ok if the input parameter is null
+  if (empty($param_value))
+  {
+    return true;
+  }
+
+  if ($is_array)
+  {
+    if (!is_array($param_value))
+    {
+      fatal_error('[Hacking attempt] the input parameter "'.$param_name.'" should be an array');
+    }
+
+    foreach ($param_value as $item_to_check)
+    {
+      if (!preg_match($pattern, $item_to_check))
+      {
+        fatal_error('[Hacking attempt] an item is not valid in input parameter "'.$param_name.'"');
+      }
+    }
+  }
+  else
+  {
+    if (!preg_match($pattern, $param_value))
+    {
+      fatal_error('[Hacking attempt] the input parameter "'.$param_name.'" is not valid');
+    }
+  }
+}
 ?>
\ No newline at end of file
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