img_auth.php

   1 <?php
   2 /**
   3  * Image authorisation script
   4  *
   5  * To use this, see http://www.mediawiki.org/wiki/Manual:Image_Authorization
   6  *
   7  * - Set $wgUploadDirectory to a non-public directory (not web accessible)
   8  * - Set $wgUploadPath to point to this file
   9  *
  10  * Optional Parameters
  11  *
  12  * - Set $wgImgAuthDetails = true if you want the reason the access was denied messages to
  13  *       be displayed instead of just the 403 error (doesn't work on IE anyway),
  14  *       otherwise it 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,
  19  *  just that it was. If you want to change this, you can set $wgImgAuthDetails to 'true'
  20  *  in localsettings.php and it will give the user the reason why access was denied.
  21  *
  22  * Your server needs to support PATH_INFO; CGI-based configurations usually don't.
  23  *
  24  * This program is free software; you can redistribute it and/or modify
  25  * it under the terms of the GNU General Public License as published by
  26  * the Free Software Foundation; either version 2 of the License, or
  27  * (at your option) any later version.
  28  *
  29  * This program is distributed in the hope that it will be useful,
  30  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  31  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  32  * GNU General Public License for more details.
  33  *
  34  * You should have received a copy of the GNU General Public License along
  35  * with this program; if not, write to the Free Software Foundation, Inc.,
  36  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  37  * http://www.gnu.org/copyleft/gpl.html
  38  *
  39  * @file
  40  */
  41
  42 define( 'MW_NO_OUTPUT_COMPRESSION', 1 );
  43 require __DIR__ . '/includes/WebStart.php';
  44 wfProfileIn( 'img_auth.php' );
  45
  46 # Set action base paths so that WebRequest::getPathInfo()
  47 # recognizes the "X" as the 'title' in ../img_auth.php/X urls.
  48 $wgArticlePath = false; # Don't let a "/*" article path clober our action path
  49 $wgActionPaths = array( "$wgUploadPath/" );
  50
  51 wfImageAuthMain();
  52 wfLogProfilingData();
  53
  54 function wfImageAuthMain() {
  55         global $wgImgAuthPublicTest, $wgImgAuthUrlPathMap, $wgRequest;
  56
  57         // See if this is a public Wiki (no protections).
  58         if ( $wgImgAuthPublicTest
  59                 && in_array( 'read', User::getGroupPermissions( array( '*' ) ), true )
  60         ) {
  61                 // This is a public wiki, so disable this script (for private wikis only)
  62                 wfForbidden( 'img-auth-accessdenied', 'img-auth-public' );
  63                 return;
  64         }
  65
  66         // Get the requested file path (source file or thumbnail)
  67         $matches = WebRequest::getPathInfo();
  68         if ( !isset( $matches['title'] ) ) {
  69                 wfForbidden( 'img-auth-accessdenied', 'img-auth-nopathinfo' );
  70                 return;
  71         }
  72         $path = $matches['title'];
  73         if ( $path && $path[0] !== '/' ) {
  74                 // Make sure $path has a leading /
  75                 $path = "/" . $path;
  76         }
  77
  78         // Check for bug 28235: QUERY_STRING overriding the correct extension
  79         $whitelist = array();
  80         $extension = FileBackend::extensionFromPath( $path );
  81         if ( $extension != '' ) {
  82                 $whitelist[] = $extension;
  83         }
  84         if ( !$wgRequest->checkUrlExtension( $whitelist ) ) {
  85                 return;
  86         }
  87
  88         // Various extensions may have their own backends that need access.
  89         // Check if there is a special backend and storage base path for this file.
  90         foreach ( $wgImgAuthUrlPathMap as $prefix => $storageDir ) {
  91                 $prefix = rtrim( $prefix, '/' ) . '/'; // implicit trailing slash
  92                 if ( strpos( $path, $prefix ) === 0 ) {
  93                         $be = FileBackendGroup::singleton()->backendFromPath( $storageDir );
  94                         $filename = $storageDir . substr( $path, strlen( $prefix ) ); // strip prefix
  95                         if ( $be->fileExists( array( 'src' => $filename ) ) ) {
  96                                 wfDebugLog( 'img_auth', "Streaming `" . $filename . "`." );
  97                                 $be->streamFile( array( 'src' => $filename ),
  98                                         array( 'Cache-Control: private', 'Vary: Cookie' ) );
  99                         } else {
 100                                 wfForbidden( 'img-auth-accessdenied', 'img-auth-nofile', $filename );
 101                         }
 102                         return;
 103                 }
 104         }
 105
 106         // Get the local file repository
 107         $repo = RepoGroup::singleton()->getRepo( 'local' );
 108
 109         // Get the full file storage path and extract the source file name.
 110         // (e.g. 120px-Foo.png => Foo.png or page2-120px-Foo.png => Foo.png).
 111         // This only applies to thumbnails, and all thumbnails should
 112         // be under a folder that has the source file name.
 113         if ( strpos( $path, '/thumb/' ) === 0 ) {
 114                 $name = wfBaseName( dirname( $path ) ); // file is a thumbnail
 115                 $filename = $repo->getZonePath( 'thumb' ) . substr( $path, 6 ); // strip "/thumb"
 116         } else {
 117                 $name = wfBaseName( $path ); // file is a source file
 118                 $filename = $repo->getZonePath( 'public' ) . $path;
 119         }
 120
 121         // Check to see if the file exists
 122         if ( !$repo->fileExists( $filename ) ) {
 123                 wfForbidden( 'img-auth-accessdenied', 'img-auth-nofile', $filename );
 124                 return;
 125         }
 126
 127         $title = Title::makeTitleSafe( NS_FILE, $name );
 128         if ( !$title instanceof Title ) { // files have valid titles
 129                 wfForbidden( 'img-auth-accessdenied', 'img-auth-badtitle', $name );
 130                 return;
 131         }
 132
 133         // Run hook for extension authorization plugins
 134         /** @var $result array */
 135         $result = null;
 136         if ( !wfRunHooks( 'ImgAuthBeforeStream', array( &$title, &$path, &$name, &$result ) ) ) {
 137                 wfForbidden( $result[0], $result[1], array_slice( $result, 2 ) );
 138                 return;
 139         }
 140
 141         // Check user authorization for this title
 142         // Checks Whitelist too
 143         if ( !$title->userCan( 'read' ) ) {
 144                 wfForbidden( 'img-auth-accessdenied', 'img-auth-noread', $name );
 145                 return;
 146         }
 147
 148         // Stream the requested file
 149         wfDebugLog( 'img_auth', "Streaming `" . $filename . "`." );
 150         $repo->streamFile( $filename, array( 'Cache-Control: private', 'Vary: Cookie' ) );
 151 }
 152
 153 /**
 154  * Issue a standard HTTP 403 Forbidden header ($msg1-a message index, not a message) and an
 155  * error message ($msg2, also a message index), (both required) then end the script
 156  * subsequent arguments to $msg2 will be passed as parameters only for replacing in $msg2
 157  * @param $msg1
 158  * @param $msg2
 159  */
 160 function wfForbidden( $msg1, $msg2 ) {
 161         global $wgImgAuthDetails;
 162
 163         $args = func_get_args();
 164         array_shift( $args );
 165         array_shift( $args );
 166         $args = ( isset( $args[0] ) && is_array( $args[0] ) ) ? $args[0] : $args;
 167
 168         $msgHdr = wfMessage( $msg1 )->escaped();
 169         $detailMsgKey = $wgImgAuthDetails ? $msg2 : 'badaccess-group0';
 170         $detailMsg = wfMessage( $detailMsgKey, $args )->escaped();
 171
 172         wfDebugLog( 'img_auth',
 173                 "wfForbidden Hdr: " . wfMessage( $msg1 )->inLanguage( 'en' )->text() . " Msg: " .
 174                         wfMessage( $msg2, $args )->inLanguage( 'en' )->text()
 175         );
 176
 177         header( 'HTTP/1.0 403 Forbidden' );
 178         header( 'Cache-Control: no-cache' );
 179         header( 'Content-Type: text/html; charset=utf-8' );
 180         echo <<<ENDS
 181 <html>
 182 <body>
 183 <h1>$msgHdr</h1>
 184 <p>$detailMsg</p>
 185 </body>
 186 </html>
 187 ENDS;
 188 }