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 $perms = User::getGroupPermissions( array( '*' ) );
  34
  35 // See if this is a public Wiki (no protections)
  36 if ( $wgImgAuthPublicTest && in_array( 'read', $perms, true ) )
  37         wfForbidden('img-auth-accessdenied','img-auth-public');
  38
  39 // Extract path and image information
  40 if( !isset( $_SERVER['PATH_INFO'] ) )
  41         wfForbidden('img-auth-accessdenied','img-auth-nopathinfo');
  42
  43 $path = $_SERVER['PATH_INFO'];
  44 $filename = realpath( $wgUploadDirectory . $_SERVER['PATH_INFO'] );
  45 $realUpload = realpath( $wgUploadDirectory );
  46
  47 // Basic directory traversal check
  48 if( substr( $filename, 0, strlen( $realUpload ) ) != $realUpload )
  49         wfForbidden('img-auth-accessdenied','img-auth-notindir');
  50
  51 // Extract the file name and chop off the size specifier
  52 // (e.g. 120px-Foo.png => Foo.png)
  53 $name = wfBaseName( $path );
  54 if( preg_match( '!\d+px-(.*)!i', $name, $m ) )
  55         $name = $m[1];
  56
  57 // Check to see if the file exists
  58 if( !file_exists( $filename ) )
  59         wfForbidden('img-auth-accessdenied','img-auth-nofile',$filename);
  60
  61 // Check to see if tried to access a directory
  62 if( is_dir( $filename ) )
  63         wfForbidden('img-auth-accessdenied','img-auth-isdir',$filename);
  64
  65
  66 $title = Title::makeTitleSafe( NS_FILE, $name );
  67
  68 // See if could create the title object
  69 if( !$title instanceof Title )
  70         wfForbidden('img-auth-accessdenied','img-auth-badtitle',$name);
  71
  72 // Run hook
  73 if (!wfRunHooks( 'ImgAuthBeforeStream', array( &$title, &$path, &$name, &$result ) ) )
  74         wfForbidden($result[0],$result[1],array_slice($result,2));
  75
  76 //  Check user authorization for this title
  77 //  UserCanRead Checks Whitelist too
  78 if( !$title->userCanRead() )
  79         wfForbidden('img-auth-accessdenied','img-auth-noread',$name);
  80
  81 // Stream the requested file
  82 wfDebugLog( 'img_auth', "Streaming `".$filename."`." );
  83 wfStreamFile( $filename, array( 'Cache-Control: private', 'Vary: Cookie' ) );
  84 wfLogProfilingData();
  85
  86 /**
  87  * Issue a standard HTTP 403 Forbidden header ($msg1-a message index, not a message) and an
  88  * error message ($msg2, also a message index), (both required) then end the script
  89  * subsequent arguments to $msg2 will be passed as parameters only for replacing in $msg2
  90  */
  91 function wfForbidden($msg1,$msg2) {
  92         global $wgImgAuthDetails;
  93         $args = func_get_args();
  94         array_shift( $args );
  95         array_shift( $args );
  96         $MsgHdr = htmlspecialchars(wfMsg($msg1));
  97         $detailMsg = (htmlspecialchars(wfMsg(($wgImgAuthDetails ? $msg2 : 'badaccess-group0'),$args)));
  98         wfDebugLog('img_auth', "wfForbidden Hdr:".wfMsgExt( $msg1, array('language' => 'en'))." Msg: ".
  99                                 wfMsgExt($msg2,array('language' => 'en'),$args));
 100         header( 'HTTP/1.0 403 Forbidden' );
 101         header( 'Cache-Control: no-cache' );
 102         header( 'Content-Type: text/html; charset=utf-8' );
 103         echo <<<ENDS
 104 <html>
 105 <body>
 106 <h1>$MsgHdr</h1>
 107 <p>$detailMsg</p>
 108 </body>
 109 </html>
 110 ENDS;
 111         wfLogProfilingData();
 112         exit();
 113 }