file_check_location

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Definition

file_check_location($source, $directory = '')
includes/file.inc, line 278

Description

Check if a file is really located inside $directory. Should be used to make sure a file specified is really located within the directory to prevent exploits.

<?php

// Returns FALSE:
  file_check_location('/www/example.com/files/../../../etc/passwd', '/www/example.com/files');

?>

Parameters

$source A string set to the file to check.

$directory A string where the file should be located.

Return value

0 for invalid path or the real path of the source.

Related topics

Name	Description
File interface	Common file handling functions.

Code

<?php
function file_check_location($source, $directory = '') {
  $check = realpath($source);
  if ($check) {
    $source = $check;
  }
  else {
    // This file does not yet exist
    $source = realpath(dirname($source)) .'/'. basename($source);
  }
  $directory = realpath($directory);
  if ($directory && strpos($source, $directory) !== 0) {
    return 0;
  }
  return $source;
}
?>