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         $path = $wgRequest->getText( 'path' );
  43         if( !$path ) {
  44         wfForbidden( 'img-auth-accessdenied', 'img-auth-nopathinfo' );
  45         }
  46 } else {
  47         $path = $_SERVER['PATH_INFO'];
  48 }
  49
  50 $filename = realpath( $wgUploadDirectory . '/' . $path );
  51 $realUpload = realpath( $wgUploadDirectory );
  52
  53 // Basic directory traversal check
  54 if( substr( $filename, 0, strlen( $realUpload ) ) != $realUpload )
  55         wfForbidden('img-auth-accessdenied','img-auth-notindir');
  56
  57 // Extract the file name and chop off the size specifier
  58 // (e.g. 120px-Foo.png => Foo.png)
  59 $name = wfBaseName( $path );
  60 if( preg_match( '!\d+px-(.*)!i', $name, $m ) )
  61         $name = $m[1];
  62
  63 // Check to see if the file exists
  64 if( !file_exists( $filename ) )
  65         wfForbidden('img-auth-accessdenied','img-auth-nofile',$filename);
  66
  67 // Check to see if tried to access a directory
  68 if( is_dir( $filename ) )
  69         wfForbidden('img-auth-accessdenied','img-auth-isdir',$filename);
  70
  71
  72 $title = Title::makeTitleSafe( NS_FILE, $name );
  73
  74 // See if could create the title object
  75 if( !$title instanceof Title )
  76         wfForbidden('img-auth-accessdenied','img-auth-badtitle',$name);
  77
  78 // Run hook
  79 if (!wfRunHooks( 'ImgAuthBeforeStream', array( &$title, &$path, &$name, &$result ) ) )
  80         wfForbidden($result[0],$result[1],array_slice($result,2));
  81
  82 //  Check user authorization for this title
  83 //  UserCanRead Checks Whitelist too
  84 if( !$title->userCanRead() )
  85         wfForbidden('img-auth-accessdenied','img-auth-noread',$name);
  86
  87 // Stream the requested file
  88 wfDebugLog( 'img_auth', "Streaming `".$filename."`." );
  89 wfStreamFile( $filename, array( 'Cache-Control: private', 'Vary: Cookie' ) );
  90 wfLogProfilingData();
  91
  92 /**
  93  * Issue a standard HTTP 403 Forbidden header ($msg1-a message index, not a message) and an
  94  * error message ($msg2, also a message index), (both required) then end the script
  95  * subsequent arguments to $msg2 will be passed as parameters only for replacing in $msg2
  96  */
  97 function wfForbidden($msg1,$msg2) {
  98         global $wgImgAuthDetails;
  99         $args = func_get_args();
 100         array_shift( $args );
 101         array_shift( $args );
 102         $MsgHdr = htmlspecialchars(wfMsg($msg1));
 103         $detailMsg = (htmlspecialchars(wfMsg(($wgImgAuthDetails ? $msg2 : 'badaccess-group0'),$args)));
 104         wfDebugLog('img_auth', "wfForbidden Hdr:".wfMsgExt( $msg1, array('language' => 'en'))." Msg: ".
 105                                 wfMsgExt($msg2,array('language' => 'en'),$args));
 106         header( 'HTTP/1.0 403 Forbidden' );
 107         header( 'Cache-Control: no-cache' );
 108         header( 'Content-Type: text/html; charset=utf-8' );
 109         echo <<<ENDS
 110 <html>
 111 <body>
 112 <h1>$MsgHdr</h1>
 113 <p>$detailMsg</p>
 114 </body>
 115 </html>
 116 ENDS;
 117         wfLogProfilingData();
 118         exit();
 119 }