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 $wgArticlePath = false; # Don't let a "/*" article path clober our action path
  40 $wgActionPaths = array( "$wgUploadPath/" );
  41
  42 wfImageAuthMain();
  43 wfLogProfilingData();
  44
  45 function wfImageAuthMain() {
  46         global $wgImgAuthPublicTest, $wgRequest, $wgUploadDirectory;
  47
  48         // See if this is a public Wiki (no protections).
  49         if ( $wgImgAuthPublicTest
  50                 && in_array( 'read', User::getGroupPermissions( array( '*' ) ), true ) )
  51         {
  52                 // This is a public wiki, so disable this script (for private wikis only)
  53                 wfForbidden( 'img-auth-accessdenied', 'img-auth-public' );
  54                 return;
  55         }
  56
  57         // Get the requested file path (source file or thumbnail)
  58         $matches = WebRequest::getPathInfo();
  59         $path = $matches['title'];
  60         if ( $path && $path[0] !== '/' ) {
  61                 // Make sure $path has a leading /
  62                 $path = "/" . $path;
  63         }
  64
  65         // Check for bug 28235: QUERY_STRING overriding the correct extension
  66         $whitelist = array();
  67         $dotPos = strrpos( $path, '.' );
  68         if ( $dotPos !== false ) {
  69                 $whitelist[] = substr( $path, $dotPos + 1 );
  70         }
  71         if ( !$wgRequest->checkUrlExtension( $whitelist ) ) {
  72                 return;
  73         }
  74
  75         // Get the full file path
  76         $filename = realpath( $wgUploadDirectory . $path );
  77         $realUpload = realpath( $wgUploadDirectory );
  78
  79         // Basic directory traversal check
  80         if ( substr( $filename, 0, strlen( $realUpload ) ) != $realUpload ) {
  81                 wfForbidden( 'img-auth-accessdenied', 'img-auth-notindir' );
  82                 return;
  83         }
  84
  85         // Check to see if the file exists
  86         if ( !file_exists( $filename ) ) {
  87                 wfForbidden( 'img-auth-accessdenied','img-auth-nofile', $filename );
  88                 return;
  89         }
  90
  91         // Check to see if tried to access a directory
  92         if ( is_dir( $filename ) ) {
  93                 wfForbidden( 'img-auth-accessdenied','img-auth-isdir', $filename );
  94                 return;
  95         }
  96
  97         // Extract the file name and chop off the size specifier.
  98         // (e.g. 120px-Foo.png => Foo.png or page2-120px-Foo.png => Foo.png).
  99         // This only applies to thumbnails, and all thumbnails should
 100         // be under a folder that has the source file name.
 101         $name = wfBaseName( $path );
 102         if ( strpos( $path, '/thumb/' ) === 0 ) {
 103                 $name = wfBaseName( dirname( $path ) ); // this file is a thumbnail
 104         }
 105
 106         $title = Title::makeTitleSafe( NS_FILE, $name );
 107         if ( !$title instanceof Title ) { // files have valid titles
 108                 wfForbidden( 'img-auth-accessdenied', 'img-auth-badtitle', $name );
 109                 return;
 110         }
 111
 112         // Run hook for extension authorization plugins
 113         if ( !wfRunHooks( 'ImgAuthBeforeStream', array( &$title, &$path, &$name, &$result ) ) ) {
 114                 wfForbidden( $result[0], $result[1], array_slice( $result, 2 ) );
 115                 return;
 116         }
 117
 118         // Check user authorization for this title
 119         // Checks Whitelist too
 120         if ( !$title->userCan( 'read' ) ) {
 121                 wfForbidden( 'img-auth-accessdenied', 'img-auth-noread', $name );
 122                 return;
 123         }
 124
 125         // Stream the requested file
 126         wfDebugLog( 'img_auth', "Streaming `".$filename."`." );
 127         StreamFile::stream( $filename, array( 'Cache-Control: private', 'Vary: Cookie' ) );
 128 }
 129
 130 /**
 131  * Issue a standard HTTP 403 Forbidden header ($msg1-a message index, not a message) and an
 132  * error message ($msg2, also a message index), (both required) then end the script
 133  * subsequent arguments to $msg2 will be passed as parameters only for replacing in $msg2
 134  * @param $msg1
 135  * @param $msg2
 136  */
 137 function wfForbidden( $msg1, $msg2 ) {
 138         global $wgImgAuthDetails;
 139
 140         $args = func_get_args();
 141         array_shift( $args );
 142         array_shift( $args );
 143
 144         $msgHdr = htmlspecialchars( wfMsg( $msg1 ) );
 145         $detailMsgKey = $wgImgAuthDetails ? $msg2 : 'badaccess-group0';
 146         $detailMsg = htmlspecialchars( wfMsg( $detailMsgKey, $args ) );
 147
 148         wfDebugLog( 'img_auth',
 149                 "wfForbidden Hdr:" . wfMsgExt( $msg1, array( 'language' => 'en' ) ). " Msg: ".
 150                 wfMsgExt( $msg2, array( 'language' => 'en' ), $args )
 151         );
 152
 153         header( 'HTTP/1.0 403 Forbidden' );
 154         header( 'Cache-Control: no-cache' );
 155         header( 'Content-Type: text/html; charset=utf-8' );
 156         echo <<<ENDS
 157 <html>
 158 <body>
 159 <h1>$msgHdr</h1>
 160 <p>$detailMsg</p>
 161 </body>
 162 </html>
 163 ENDS;
 164 }