img_auth.php

   1 <?php
   2 /**
   3  * Image authorisation script
   4  *
   5  * To use this, see https://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  *
  16  *  For security reasons, you usually don't want your user to know *why* access was denied,
  17  *  just that it was. If you want to change this, you can set $wgImgAuthDetails to 'true'
  18  *  in localsettings.php and it will give the user the reason why access was denied.
  19  *
  20  * Your server needs to support REQUEST_URI or PATH_INFO; CGI-based
  21  * configurations sometimes don't.
  22  *
  23  * This program is free software; you can redistribute it and/or modify
  24  * it under the terms of the GNU General Public License as published by
  25  * the Free Software Foundation; either version 2 of the License, or
  26  * (at your option) any later version.
  27  *
  28  * This program is distributed in the hope that it will be useful,
  29  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  30  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  31  * GNU General Public License for more details.
  32  *
  33  * You should have received a copy of the GNU General Public License along
  34  * with this program; if not, write to the Free Software Foundation, Inc.,
  35  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  36  * http://www.gnu.org/copyleft/gpl.html
  37  *
  38  * @file
  39  */
  40
  41 define( 'MW_NO_OUTPUT_COMPRESSION', 1 );
  42 require __DIR__ . '/includes/WebStart.php';
  43
  44 # Set action base paths so that WebRequest::getPathInfo()
  45 # recognizes the "X" as the 'title' in ../img_auth.php/X urls.
  46 $wgArticlePath = false; # Don't let a "/*" article path clober our action path
  47 $wgActionPaths = [ "$wgUploadPath/" ];
  48
  49 wfImageAuthMain();
  50
  51 $mediawiki = new MediaWiki();
  52 $mediawiki->doPostOutputShutdown( 'fast' );
  53
  54 function wfImageAuthMain() {
  55         global $wgImgAuthUrlPathMap;
  56
  57         $request = RequestContext::getMain()->getRequest();
  58         $publicWiki = in_array( 'read', User::getGroupPermissions( [ '*' ] ), true );
  59
  60         // Get the requested file path (source file or thumbnail)
  61         $matches = WebRequest::getPathInfo();
  62         if ( !isset( $matches['title'] ) ) {
  63                 wfForbidden( 'img-auth-accessdenied', 'img-auth-nopathinfo' );
  64                 return;
  65         }
  66         $path = $matches['title'];
  67         if ( $path && $path[0] !== '/' ) {
  68                 // Make sure $path has a leading /
  69                 $path = "/" . $path;
  70         }
  71
  72         // Check for T30235: QUERY_STRING overriding the correct extension
  73         $whitelist = [];
  74         $extension = FileBackend::extensionFromPath( $path, 'rawcase' );
  75         if ( $extension != '' ) {
  76                 $whitelist[] = $extension;
  77         }
  78         if ( !$request->checkUrlExtension( $whitelist ) ) {
  79                 return;
  80         }
  81
  82         $user = RequestContext::getMain()->getUser();
  83
  84         // Various extensions may have their own backends that need access.
  85         // Check if there is a special backend and storage base path for this file.
  86         foreach ( $wgImgAuthUrlPathMap as $prefix => $storageDir ) {
  87                 $prefix = rtrim( $prefix, '/' ) . '/'; // implicit trailing slash
  88                 if ( strpos( $path, $prefix ) === 0 ) {
  89                         $be = FileBackendGroup::singleton()->backendFromPath( $storageDir );
  90                         $filename = $storageDir . substr( $path, strlen( $prefix ) ); // strip prefix
  91                         // Check basic user authorization
  92                         if ( !$user->isAllowed( 'read' ) ) {
  93                                 wfForbidden( 'img-auth-accessdenied', 'img-auth-noread', $path );
  94                                 return;
  95                         }
  96                         if ( $be->fileExists( [ 'src' => $filename ] ) ) {
  97                                 wfDebugLog( 'img_auth', "Streaming `" . $filename . "`." );
  98                                 $be->streamFile( [ 'src' => $filename ],
  99                                         [ 'Cache-Control: private', 'Vary: Cookie' ] );
 100                         } else {
 101                                 wfForbidden( 'img-auth-accessdenied', 'img-auth-nofile', $path );
 102                         }
 103                         return;
 104                 }
 105         }
 106
 107         // Get the local file repository
 108         $repo = RepoGroup::singleton()->getRepo( 'local' );
 109         $zone = strstr( ltrim( $path, '/' ), '/', true );
 110
 111         // Get the full file storage path and extract the source file name.
 112         // (e.g. 120px-Foo.png => Foo.png or page2-120px-Foo.png => Foo.png).
 113         // This only applies to thumbnails/transcoded, and each of them should
 114         // be under a folder that has the source file name.
 115         if ( $zone === 'thumb' || $zone === 'transcoded' ) {
 116                 $name = wfBaseName( dirname( $path ) );
 117                 $filename = $repo->getZonePath( $zone ) . substr( $path, strlen( "/" . $zone ) );
 118                 // Check to see if the file exists
 119                 if ( !$repo->fileExists( $filename ) ) {
 120                         wfForbidden( 'img-auth-accessdenied', 'img-auth-nofile', $filename );
 121                         return;
 122                 }
 123         } else {
 124                 $name = wfBaseName( $path ); // file is a source file
 125                 $filename = $repo->getZonePath( 'public' ) . $path;
 126                 // Check to see if the file exists and is not deleted
 127                 $bits = explode( '!', $name, 2 );
 128                 if ( substr( $path, 0, 9 ) === '/archive/' && count( $bits ) == 2 ) {
 129                         $file = $repo->newFromArchiveName( $bits[1], $name );
 130                 } else {
 131                         $file = $repo->newFile( $name );
 132                 }
 133                 if ( !$file->exists() || $file->isDeleted( File::DELETED_FILE ) ) {
 134                         wfForbidden( 'img-auth-accessdenied', 'img-auth-nofile', $filename );
 135                         return;
 136                 }
 137         }
 138
 139         $headers = []; // extra HTTP headers to send
 140
 141         $title = Title::makeTitleSafe( NS_FILE, $name );
 142
 143         if ( !$publicWiki ) {
 144                 // For private wikis, run extra auth checks and set cache control headers
 145                 $headers['Cache-Control'] = 'private';
 146                 $headers['Vary'] = 'Cookie';
 147
 148                 if ( !$title instanceof Title ) { // files have valid titles
 149                         wfForbidden( 'img-auth-accessdenied', 'img-auth-badtitle', $name );
 150                         return;
 151                 }
 152
 153                 // Run hook for extension authorization plugins
 154                 /** @var array $result */
 155                 $result = null;
 156                 if ( !Hooks::run( 'ImgAuthBeforeStream', [ &$title, &$path, &$name, &$result ] ) ) {
 157                         wfForbidden( $result[0], $result[1], array_slice( $result, 2 ) );
 158                         return;
 159                 }
 160
 161                 // Check user authorization for this title
 162                 // Checks Whitelist too
 163                 $permissionManager = \MediaWiki\MediaWikiServices::getInstance()->getPermissionManager();
 164
 165                 if ( !$permissionManager->userCan( 'read', $user, $title ) ) {
 166                         wfForbidden( 'img-auth-accessdenied', 'img-auth-noread', $name );
 167                         return;
 168                 }
 169         }
 170
 171         if ( isset( $_SERVER['HTTP_RANGE'] ) ) {
 172                 $headers['Range'] = $_SERVER['HTTP_RANGE'];
 173         }
 174         if ( isset( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
 175                 $headers['If-Modified-Since'] = $_SERVER['HTTP_IF_MODIFIED_SINCE'];
 176         }
 177
 178         if ( $request->getCheck( 'download' ) ) {
 179                 $headers['Content-Disposition'] = 'attachment';
 180         }
 181
 182         // Allow modification of headers before streaming a file
 183         Hooks::run( 'ImgAuthModifyHeaders', [ $title->getTitleValue(), &$headers ] );
 184
 185         // Stream the requested file
 186         list( $headers, $options ) = HTTPFileStreamer::preprocessHeaders( $headers );
 187         wfDebugLog( 'img_auth', "Streaming `" . $filename . "`." );
 188         $repo->streamFileWithStatus( $filename, $headers, $options );
 189 }
 190
 191 /**
 192  * Issue a standard HTTP 403 Forbidden header ($msg1-a message index, not a message) and an
 193  * error message ($msg2, also a message index), (both required) then end the script
 194  * subsequent arguments to $msg2 will be passed as parameters only for replacing in $msg2
 195  * @param string $msg1
 196  * @param string $msg2
 197  * @param mixed ...$args To pass as params to wfMessage() with $msg2. Either variadic, or a single
 198  *   array argument.
 199  */
 200 function wfForbidden( $msg1, $msg2, ...$args ) {
 201         global $wgImgAuthDetails;
 202
 203         $args = ( isset( $args[0] ) && is_array( $args[0] ) ) ? $args[0] : $args;
 204
 205         $msgHdr = wfMessage( $msg1 )->escaped();
 206         $detailMsgKey = $wgImgAuthDetails ? $msg2 : 'badaccess-group0';
 207         $detailMsg = wfMessage( $detailMsgKey, $args )->escaped();
 208
 209         wfDebugLog( 'img_auth',
 210                 "wfForbidden Hdr: " . wfMessage( $msg1 )->inLanguage( 'en' )->text() . " Msg: " .
 211                         wfMessage( $msg2, $args )->inLanguage( 'en' )->text()
 212         );
 213
 214         HttpStatus::header( 403 );
 215         header( 'Cache-Control: no-cache' );
 216         header( 'Content-Type: text/html; charset=utf-8' );
 217         echo <<<ENDS
 218 <!DOCTYPE html>
 219 <html>
 220 <head>
 221 <meta charset="UTF-8" />
 222 <title>$msgHdr</title>
 223 </head>
 224 <body>
 225 <h1>$msgHdr</h1>
 226 <p>$detailMsg</p>
 227 </body>
 228 </html>
 229 ENDS;
 230 }