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
  14  *       be displayed instead of just the 403 error (doesn't work on IE anyway),
  15  *       otherwise it will only appear in error logs
  16  * - Set $wgImgAuthPublicTest false if you don't want to just check and see if all are public
  17  *       must be set to false if using specific restrictions such as LockDown or NSFileRepo
  18  *
  19  *  For security reasons, you usually don't want your user to know *why* access was denied,
  20  *  just that it was. If you want to change this, you can set $wgImgAuthDetails to 'true'
  21  *  in localsettings.php and it will give the user the reason why access was denied.
  22  *
  23  * Your server needs to support PATH_INFO; CGI-based configurations usually don't.
  24  *
  25  * @file
  26  *
  27  **/
  28
  29 define( 'MW_NO_OUTPUT_COMPRESSION', 1 );
  30 if ( isset( $_SERVER['MW_COMPILED'] ) ) {
  31         require ( 'phase3/includes/WebStart.php' );
  32 } else {
  33         require ( dirname( __FILE__ ) . '/includes/WebStart.php' );
  34 }
  35 wfProfileIn( 'img_auth.php' );
  36
  37 # Set action base paths so that WebRequest::getPathInfo()
  38 # recognizes the "X" as the 'title' in ../image_auth/X urls.
  39 $wgActionPaths[] = $_SERVER['SCRIPT_NAME'];
  40
  41 wfImageAuthMain();
  42 wfLogProfilingData();
  43
  44 function wfImageAuthMain() {
  45         global $wgImgAuthPublicTest, $wgRequest, $wgUploadDirectory;
  46
  47         // See if this is a public Wiki (no protections).
  48         if ( $wgImgAuthPublicTest
  49                 && in_array( 'read', User::getGroupPermissions( array( '*' ) ), true ) )
  50         {
  51                 // This is a public wiki, so disable this script (for private wikis only)
  52                 wfForbidden( 'img-auth-accessdenied', 'img-auth-public' );
  53                 return;
  54         }
  55
  56         // Get the requested file path (source file or thumbnail)
  57         $matches = WebRequest::getPathInfo();
  58         $path = $matches['title']; // path with leading '/'
  59
  60         // Check for bug 28235: QUERY_STRING overriding the correct extension
  61         $whitelist = array();
  62         $dotPos = strrpos( $path, '.' );
  63         if ( $dotPos !== false ) {
  64                 $whitelist[] = substr( $path, $dotPos + 1 );
  65         }
  66         if ( !$wgRequest->checkUrlExtension( $whitelist ) ) {
  67                 return;
  68         }
  69
  70         // Get the full file path
  71         $filename = realpath( $wgUploadDirectory . $path );
  72         $realUpload = realpath( $wgUploadDirectory );
  73
  74         // Basic directory traversal check
  75         if ( substr( $filename, 0, strlen( $realUpload ) ) != $realUpload ) {
  76                 wfForbidden( 'img-auth-accessdenied', 'img-auth-notindir' );
  77                 return;
  78         }
  79
  80         // Check to see if the file exists
  81         if ( !file_exists( $filename ) ) {
  82                 wfForbidden( 'img-auth-accessdenied','img-auth-nofile', $filename );
  83                 return;
  84         }
  85
  86         // Check to see if tried to access a directory
  87         if ( is_dir( $filename ) ) {
  88                 wfForbidden( 'img-auth-accessdenied','img-auth-isdir', $filename );
  89                 return;
  90         }
  91
  92         // Extract the file name and chop off the size specifier
  93         // (e.g. 120px-Foo.png => Foo.png or page2-120px-Foo.png => Foo.png).
  94         // This only applies to thumbnails, and all thumbnails have a -px specifier.
  95         $name = wfBaseName( $path );
  96         if ( preg_match( '!(?:[^-]*-)*?\d+px-(.*)!i', $name, $m ) ) {
  97                 $name = $m[1]; // this file is a thumbnail
  98         }
  99
 100         $title = Title::makeTitleSafe( NS_FILE, $name );
 101         if ( !$title instanceof Title ) { // files have valid titles
 102                 wfForbidden( 'img-auth-accessdenied', 'img-auth-badtitle', $name );
 103                 return;
 104         }
 105
 106         // Run hook for extension authorization plugins
 107         if ( !wfRunHooks( 'ImgAuthBeforeStream', array( &$title, &$path, &$name, &$result ) ) ) {
 108                 wfForbidden( $result[0], $result[1], array_slice( $result, 2 ) );
 109                 return;
 110         }
 111
 112         // Check user authorization for this title
 113         // UserCanRead Checks Whitelist too
 114         if( !$title->userCanRead() ) {
 115                 wfForbidden( 'img-auth-accessdenied', 'img-auth-noread', $name );
 116                 return;
 117         }
 118
 119         // Stream the requested file
 120         wfDebugLog( 'img_auth', "Streaming `".$filename."`." );
 121         StreamFile::stream( $filename, array( 'Cache-Control: private', 'Vary: Cookie' ) );
 122 }
 123
 124 /**
 125  * Issue a standard HTTP 403 Forbidden header ($msg1-a message index, not a message) and an
 126  * error message ($msg2, also a message index), (both required) then end the script
 127  * subsequent arguments to $msg2 will be passed as parameters only for replacing in $msg2
 128  * @param $msg1
 129  * @param $msg2
 130  */
 131 function wfForbidden( $msg1, $msg2 ) {
 132         global $wgImgAuthDetails;
 133
 134         $args = func_get_args();
 135         array_shift( $args );
 136         array_shift( $args );
 137
 138         $msgHdr = htmlspecialchars( wfMsg( $msg1 ) );
 139         $detailMsgKey = $wgImgAuthDetails ? $msg2 : 'badaccess-group0';
 140         $detailMsg = htmlspecialchars( wfMsg( $detailMsgKey, $args ) );
 141
 142         wfDebugLog( 'img_auth',
 143                 "wfForbidden Hdr:" . wfMsgExt( $msg1, array( 'language' => 'en' ) ). " Msg: ".
 144                 wfMsgExt( $msg2, array( 'language' => 'en' ), $args )
 145         );
 146
 147         header( 'HTTP/1.0 403 Forbidden' );
 148         header( 'Cache-Control: no-cache' );
 149         header( 'Content-Type: text/html; charset=utf-8' );
 150         echo <<<ENDS
 151 <html>
 152 <body>
 153 <h1>$msgHdr</h1>
 154 <p>$detailMsg</p>
 155 </body>
 156 </html>
 157 ENDS;
 158 }