img_auth.php

   1 <?php
   2
   3 /**
   4  * Image authorisation script
   5  *
   6  * To use this, see http://www.mediawiki.org/wiki/Manual:Image_Authorization
   7  *
   8  * - Set $wgUploadDirectory to a non-public directory (not web accessible)
   9  * - Set $wgUploadPath to point to this file
  10  *
  11  * Optional Parameters
  12  *
  13  * - Set $wgImgAuthDetails = true if you want the reason the access was denied messages to be displayed
  14  *       instead of just the 403 error (doesn't work on IE anyway),  otherwise will only appear in error logs
  15  * - Set $wgImgAuthPublicTest false if you don't want to just check and see if all are public
  16  *       must be set to false if using specific restrictions such as LockDown or NSFileRepo
  17  *
  18  *  For security reasons, you usually don't want your user to know *why* access was denied, just that it was.
  19  *  If you want to change this, you can set $wgImgAuthDetails to 'true' in localsettings.php and it will give the user the reason
  20  *  why access was denied.
  21  *
  22  * Your server needs to support PATH_INFO; CGI-based configurations usually don't.
  23  *
  24  * @file
  25  *
  26  **/
  27
  28 define( 'MW_NO_OUTPUT_COMPRESSION', 1 );
  29 require_once( dirname( __FILE__ ) . '/includes/WebStart.php' );
  30 wfProfileIn( 'img_auth.php' );
  31 require_once( dirname( __FILE__ ) . '/includes/StreamFile.php' );
  32
  33 // See if this is a public Wiki (no protections)
  34 if ( $wgImgAuthPublicTest
  35         && in_array( 'read', User::getGroupPermissions( array( '*' ) ), true ) )
  36 {
  37         wfForbidden('img-auth-accessdenied','img-auth-public');
  38 }
  39
  40 // Extract path and image information
  41 if( !isset( $_SERVER['PATH_INFO'] ) ) {
  42         if( isset( $_GET['path'] ) ) $path = $_GET['path'];
  43         else wfForbidden('img-auth-accessdenied','img-auth-nopathinfo');
  44 } else {
  45         $path = $_SERVER['PATH_INFO'];
  46 }
  47
  48 $filename = realpath( $wgUploadDirectory . '/' . $path );
  49 $realUpload = realpath( $wgUploadDirectory );
  50
  51 // Basic directory traversal check
  52 if( substr( $filename, 0, strlen( $realUpload ) ) != $realUpload )
  53         wfForbidden('img-auth-accessdenied','img-auth-notindir');
  54
  55 // Extract the file name and chop off the size specifier
  56 // (e.g. 120px-Foo.png => Foo.png)
  57 $name = wfBaseName( $path );
  58 if( preg_match( '!\d+px-(.*)!i', $name, $m ) )
  59         $name = $m[1];
  60
  61 // Check to see if the file exists
  62 if( !file_exists( $filename ) )
  63         wfForbidden('img-auth-accessdenied','img-auth-nofile',$filename);
  64
  65 // Check to see if tried to access a directory
  66 if( is_dir( $filename ) )
  67         wfForbidden('img-auth-accessdenied','img-auth-isdir',$filename);
  68
  69
  70 $title = Title::makeTitleSafe( NS_FILE, $name );
  71
  72 // See if could create the title object
  73 if( !$title instanceof Title )
  74         wfForbidden('img-auth-accessdenied','img-auth-badtitle',$name);
  75
  76 // Run hook
  77 if (!wfRunHooks( 'ImgAuthBeforeStream', array( &$title, &$path, &$name, &$result ) ) )
  78         wfForbidden($result[0],$result[1],array_slice($result,2));
  79
  80 //  Check user authorization for this title
  81 //  UserCanRead Checks Whitelist too
  82 if( !$title->userCanRead() )
  83         wfForbidden('img-auth-accessdenied','img-auth-noread',$name);
  84
  85 // Stream the requested file
  86 wfDebugLog( 'img_auth', "Streaming `".$filename."`." );
  87 wfStreamFile( $filename, array( 'Cache-Control: private', 'Vary: Cookie' ) );
  88 wfLogProfilingData();
  89
  90 /**
  91  * Issue a standard HTTP 403 Forbidden header ($msg1-a message index, not a message) and an
  92  * error message ($msg2, also a message index), (both required) then end the script
  93  * subsequent arguments to $msg2 will be passed as parameters only for replacing in $msg2
  94  */
  95 function wfForbidden($msg1,$msg2) {
  96         global $wgImgAuthDetails;
  97         $args = func_get_args();
  98         array_shift( $args );
  99         array_shift( $args );
 100         $MsgHdr = htmlspecialchars(wfMsg($msg1));
 101         $detailMsg = (htmlspecialchars(wfMsg(($wgImgAuthDetails ? $msg2 : 'badaccess-group0'),$args)));
 102         wfDebugLog('img_auth', "wfForbidden Hdr:".wfMsgExt( $msg1, array('language' => 'en'))." Msg: ".
 103                                 wfMsgExt($msg2,array('language' => 'en'),$args));
 104         header( 'HTTP/1.0 403 Forbidden' );
 105         header( 'Cache-Control: no-cache' );
 106         header( 'Content-Type: text/html; charset=utf-8' );
 107         echo <<<ENDS
 108 <html>
 109 <body>
 110 <h1>$MsgHdr</h1>
 111 <p>$detailMsg</p>
 112 </body>
 113 </html>
 114 ENDS;
 115         wfLogProfilingData();
 116         exit();
 117 }