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 PATH_INFO; CGI-based configurations usually don't.
  21  *
  22  * This program is free software; you can redistribute it and/or modify
  23  * it under the terms of the GNU General Public License as published by
  24  * the Free Software Foundation; either version 2 of the License, or
  25  * (at your option) any later version.
  26  *
  27  * This program is distributed in the hope that it will be useful,
  28  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  29  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  30  * GNU General Public License for more details.
  31  *
  32  * You should have received a copy of the GNU General Public License along
  33  * with this program; if not, write to the Free Software Foundation, Inc.,
  34  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  35  * http://www.gnu.org/copyleft/gpl.html
  36  *
  37  * @file
  38  */
  39
  40 define( 'MW_NO_OUTPUT_COMPRESSION', 1 );
  41 require __DIR__ . '/includes/WebStart.php';
  42
  43 # Set action base paths so that WebRequest::getPathInfo()
  44 # recognizes the "X" as the 'title' in ../img_auth.php/X urls.
  45 $wgArticlePath = false; # Don't let a "/*" article path clober our action path
  46 $wgActionPaths = [ "$wgUploadPath/" ];
  47
  48 wfImageAuthMain();
  49
  50 $mediawiki = new MediaWiki();
  51 $mediawiki->doPostOutputShutdown( 'fast' );
  52
  53 function wfImageAuthMain() {
  54         global $wgImgAuthUrlPathMap;
  55
  56         $request = RequestContext::getMain()->getRequest();
  57         $publicWiki = in_array( 'read', User::getGroupPermissions( [ '*' ] ), true );
  58
  59         // Get the requested file path (source file or thumbnail)
  60         $matches = WebRequest::getPathInfo();
  61         if ( !isset( $matches['title'] ) ) {
  62                 wfForbidden( 'img-auth-accessdenied', 'img-auth-nopathinfo' );
  63                 return;
  64         }
  65         $path = $matches['title'];
  66         if ( $path && $path[0] !== '/' ) {
  67                 // Make sure $path has a leading /
  68                 $path = "/" . $path;
  69         }
  70
  71         // Check for bug 28235: QUERY_STRING overriding the correct extension
  72         $whitelist = [];
  73         $extension = FileBackend::extensionFromPath( $path, 'rawcase' );
  74         if ( $extension != '' ) {
  75                 $whitelist[] = $extension;
  76         }
  77         if ( !$request->checkUrlExtension( $whitelist ) ) {
  78                 return;
  79         }
  80
  81         // Various extensions may have their own backends that need access.
  82         // Check if there is a special backend and storage base path for this file.
  83         foreach ( $wgImgAuthUrlPathMap as $prefix => $storageDir ) {
  84                 $prefix = rtrim( $prefix, '/' ) . '/'; // implicit trailing slash
  85                 if ( strpos( $path, $prefix ) === 0 ) {
  86                         $be = FileBackendGroup::singleton()->backendFromPath( $storageDir );
  87                         $filename = $storageDir . substr( $path, strlen( $prefix ) ); // strip prefix
  88                         // Check basic user authorization
  89                         if ( !RequestContext::getMain()->getUser()->isAllowed( 'read' ) ) {
  90                                 wfForbidden( 'img-auth-accessdenied', 'img-auth-noread', $path );
  91                                 return;
  92                         }
  93                         if ( $be->fileExists( [ 'src' => $filename ] ) ) {
  94                                 wfDebugLog( 'img_auth', "Streaming `" . $filename . "`." );
  95                                 $be->streamFile( [ 'src' => $filename ],
  96                                         [ 'Cache-Control: private', 'Vary: Cookie' ] );
  97                         } else {
  98                                 wfForbidden( 'img-auth-accessdenied', 'img-auth-nofile', $path );
  99                         }
 100                         return;
 101                 }
 102         }
 103
 104         // Get the local file repository
 105         $repo = RepoGroup::singleton()->getRepo( 'local' );
 106         $zone = strstr( ltrim( $path, '/' ), '/', true );
 107
 108         // Get the full file storage path and extract the source file name.
 109         // (e.g. 120px-Foo.png => Foo.png or page2-120px-Foo.png => Foo.png).
 110         // This only applies to thumbnails/transcoded, and each of them should
 111         // be under a folder that has the source file name.
 112         if ( $zone === 'thumb' || $zone === 'transcoded' ) {
 113                 $name = wfBaseName( dirname( $path ) );
 114                 $filename = $repo->getZonePath( $zone ) . substr( $path, strlen( "/" . $zone ) );
 115                 // Check to see if the file exists
 116                 if ( !$repo->fileExists( $filename ) ) {
 117                         wfForbidden( 'img-auth-accessdenied', 'img-auth-nofile', $filename );
 118                         return;
 119                 }
 120         } else {
 121                 $name = wfBaseName( $path ); // file is a source file
 122                 $filename = $repo->getZonePath( 'public' ) . $path;
 123                 // Check to see if the file exists and is not deleted
 124                 $bits = explode( '!', $name, 2 );
 125                 if ( substr( $path, 0, 9 ) === '/archive/' && count( $bits ) == 2 ) {
 126                         $file = $repo->newFromArchiveName( $bits[1], $name );
 127                 } else {
 128                         $file = $repo->newFile( $name );
 129                 }
 130                 if ( !$file->exists() || $file->isDeleted( File::DELETED_FILE ) ) {
 131                         wfForbidden( 'img-auth-accessdenied', 'img-auth-nofile', $filename );
 132                         return;
 133                 }
 134         }
 135
 136         $headers = []; // extra HTTP headers to send
 137
 138         if ( !$publicWiki ) {
 139                 // For private wikis, run extra auth checks and set cache control headers
 140                 $headers[] = 'Cache-Control: private';
 141                 $headers[] = 'Vary: Cookie';
 142
 143                 $title = Title::makeTitleSafe( NS_FILE, $name );
 144                 if ( !$title instanceof Title ) { // files have valid titles
 145                         wfForbidden( 'img-auth-accessdenied', 'img-auth-badtitle', $name );
 146                         return;
 147                 }
 148
 149                 // Run hook for extension authorization plugins
 150                 /** @var $result array */
 151                 $result = null;
 152                 if ( !Hooks::run( 'ImgAuthBeforeStream', [ &$title, &$path, &$name, &$result ] ) ) {
 153                         wfForbidden( $result[0], $result[1], array_slice( $result, 2 ) );
 154                         return;
 155                 }
 156
 157                 // Check user authorization for this title
 158                 // Checks Whitelist too
 159                 if ( !$title->userCan( 'read' ) ) {
 160                         wfForbidden( 'img-auth-accessdenied', 'img-auth-noread', $name );
 161                         return;
 162                 }
 163         }
 164
 165         if ( $request->getCheck( 'download' ) ) {
 166                 $headers[] = 'Content-Disposition: attachment';
 167         }
 168
 169         // Stream the requested file
 170         wfDebugLog( 'img_auth', "Streaming `" . $filename . "`." );
 171         $repo->streamFile( $filename, $headers );
 172 }
 173
 174 /**
 175  * Issue a standard HTTP 403 Forbidden header ($msg1-a message index, not a message) and an
 176  * error message ($msg2, also a message index), (both required) then end the script
 177  * subsequent arguments to $msg2 will be passed as parameters only for replacing in $msg2
 178  * @param string $msg1
 179  * @param string $msg2
 180  */
 181 function wfForbidden( $msg1, $msg2 ) {
 182         global $wgImgAuthDetails;
 183
 184         $args = func_get_args();
 185         array_shift( $args );
 186         array_shift( $args );
 187         $args = ( isset( $args[0] ) && is_array( $args[0] ) ) ? $args[0] : $args;
 188
 189         $msgHdr = wfMessage( $msg1 )->escaped();
 190         $detailMsgKey = $wgImgAuthDetails ? $msg2 : 'badaccess-group0';
 191         $detailMsg = wfMessage( $detailMsgKey, $args )->escaped();
 192
 193         wfDebugLog( 'img_auth',
 194                 "wfForbidden Hdr: " . wfMessage( $msg1 )->inLanguage( 'en' )->text() . " Msg: " .
 195                         wfMessage( $msg2, $args )->inLanguage( 'en' )->text()
 196         );
 197
 198         HttpStatus::header( 403 );
 199         header( 'Cache-Control: no-cache' );
 200         header( 'Content-Type: text/html; charset=utf-8' );
 201         echo <<<ENDS
 202 <!DOCTYPE html>
 203 <html>
 204 <head>
 205 <meta charset="UTF-8" />
 206 <title>$msgHdr</title>
 207 </head>
 208 <body>
 209 <h1>$msgHdr</h1>
 210 <p>$detailMsg</p>
 211 </body>
 212 </html>
 213 ENDS;
 214 }