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 if ( isset( $_SERVER['MW_COMPILED'] ) ) {
  30         require ( 'phase3/includes/WebStart.php' );
  31 } else {
  32         require ( dirname( __FILE__ ) . '/includes/WebStart.php' );
  33 }
  34 wfProfileIn( 'img_auth.php' );
  35
  36 $wgActionPaths[] = $_SERVER['SCRIPT_NAME'];
  37 // See if this is a public Wiki (no protections)
  38 if ( $wgImgAuthPublicTest
  39         && in_array( 'read', User::getGroupPermissions( array( '*' ) ), true ) )
  40 {
  41         wfForbidden('img-auth-accessdenied','img-auth-public');
  42 }
  43
  44 $matches = WebRequest::getPathInfo();
  45 $path = $matches['title'];
  46
  47 // Check for bug 28235: QUERY_STRING overriding the correct extension
  48 $dotPos = strrpos( $path, '.' );
  49 $whitelist = array();
  50 if ( $dotPos !== false ) {
  51         $whitelist[] = substr( $path, $dotPos + 1 );
  52 }
  53 if ( !$wgRequest->checkUrlExtension( $whitelist ) ) {
  54         return;
  55 }
  56
  57 $filename = realpath( $wgUploadDirectory . $path );
  58 $realUpload = realpath( $wgUploadDirectory );
  59
  60 // Basic directory traversal check
  61 if( substr( $filename, 0, strlen( $realUpload ) ) != $realUpload ) {
  62         wfForbidden('img-auth-accessdenied','img-auth-notindir');
  63 }
  64
  65 // Extract the file name and chop off the size specifier
  66 // (e.g. 120px-Foo.png => Foo.png)
  67 $name = wfBaseName( $path );
  68 if( preg_match( '!\d+px-(.*)!i', $name, $m ) ) {
  69         $name = $m[1];
  70 }
  71
  72 // Check to see if the file exists
  73 if( !file_exists( $filename ) ) {
  74         wfForbidden('img-auth-accessdenied','img-auth-nofile',$filename);
  75 }
  76
  77 // Check to see if tried to access a directory
  78 if( is_dir( $filename ) ) {
  79         wfForbidden('img-auth-accessdenied','img-auth-isdir',$filename);
  80 }
  81
  82 $title = Title::makeTitleSafe( NS_FILE, $name );
  83
  84 // See if could create the title object
  85 if( !$title instanceof Title ) {
  86         wfForbidden('img-auth-accessdenied','img-auth-badtitle',$name);
  87 }
  88
  89 // Run hook
  90 if (!wfRunHooks( 'ImgAuthBeforeStream', array( &$title, &$path, &$name, &$result ) ) ) {
  91         wfForbidden($result[0],$result[1],array_slice($result,2));
  92 }
  93
  94 //  Check user authorization for this title
  95 //  UserCanRead Checks Whitelist too
  96 if( !$title->userCanRead() ) {
  97         wfForbidden('img-auth-accessdenied','img-auth-noread',$name);
  98 }
  99
 100 // Stream the requested file
 101 wfDebugLog( 'img_auth', "Streaming `".$filename."`." );
 102 StreamFile::stream( $filename, array( 'Cache-Control: private', 'Vary: Cookie' ) );
 103 wfLogProfilingData();
 104
 105 /**
 106  * Issue a standard HTTP 403 Forbidden header ($msg1-a message index, not a message) and an
 107  * error message ($msg2, also a message index), (both required) then end the script
 108  * subsequent arguments to $msg2 will be passed as parameters only for replacing in $msg2
 109  * @param $msg1
 110  * @param $msg2
 111  */
 112 function wfForbidden( $msg1, $msg2 ) {
 113         global $wgImgAuthDetails;
 114         $args = func_get_args();
 115         array_shift( $args );
 116         array_shift( $args );
 117         $MsgHdr = htmlspecialchars( wfMsg( $msg1 ) );
 118         $detailMsg = ( htmlspecialchars( wfMsg( ( $wgImgAuthDetails ? $msg2 : 'badaccess-group0' ), $args ) ) );
 119         wfDebugLog('img_auth', "wfForbidden Hdr:".wfMsgExt( $msg1, array( 'language' => 'en' ) )." Msg: ".
 120                 wfMsgExt( $msg2, array('language' => 'en' ), $args ) );
 121         header( 'HTTP/1.0 403 Forbidden' );
 122         header( 'Cache-Control: no-cache' );
 123         header( 'Content-Type: text/html; charset=utf-8' );
 124         echo <<<ENDS
 125 <html>
 126 <body>
 127 <h1>$MsgHdr</h1>
 128 <p>$detailMsg</p>
 129 </body>
 130 </html>
 131 ENDS;
 132         wfLogProfilingData();
 133         exit();
 134 }