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 wfProfileIn( 'img_auth.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 $wgActionPaths = array( "$wgUploadPath/" );
  48
  49 wfImageAuthMain();
  50 wfLogProfilingData();
  51 // Commit and close up!
  52 $factory = wfGetLBFactory();
  53 $factory->commitMasterChanges();
  54 $factory->shutdown();
  55
  56 function wfImageAuthMain() {
  57         global $wgImgAuthUrlPathMap;
  58
  59         $request = RequestContext::getMain()->getRequest();
  60         $publicWiki = in_array( 'read', User::getGroupPermissions( array( '*' ) ), true );
  61
  62         // Get the requested file path (source file or thumbnail)
  63         $matches = WebRequest::getPathInfo();
  64         if ( !isset( $matches['title'] ) ) {
  65                 wfForbidden( 'img-auth-accessdenied', 'img-auth-nopathinfo' );
  66                 return;
  67         }
  68         $path = $matches['title'];
  69         if ( $path && $path[0] !== '/' ) {
  70                 // Make sure $path has a leading /
  71                 $path = "/" . $path;
  72         }
  73
  74         // Check for bug 28235: QUERY_STRING overriding the correct extension
  75         $whitelist = array();
  76         $extension = FileBackend::extensionFromPath( $path, 'rawcase' );
  77         if ( $extension != '' ) {
  78                 $whitelist[] = $extension;
  79         }
  80         if ( !$request->checkUrlExtension( $whitelist ) ) {
  81                 return;
  82         }
  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 ( !RequestContext::getMain()->getUser()->isAllowed( 'read' ) ) {
  93                                 wfForbidden( 'img-auth-accessdenied', 'img-auth-noread', $path );
  94                                 return;
  95                         }
  96                         if ( $be->fileExists( array( 'src' => $filename ) ) ) {
  97                                 wfDebugLog( 'img_auth', "Streaming `" . $filename . "`." );
  98                                 $be->streamFile( array( 'src' => $filename ),
  99                                         array( '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         $headers = array(); // extra HTTP headers to send
 140
 141         if ( !$publicWiki ) {
 142                 // For private wikis, run extra auth checks and set cache control headers
 143                 $headers[] = 'Cache-Control: private';
 144                 $headers[] = 'Vary: Cookie';
 145
 146                 $title = Title::makeTitleSafe( NS_FILE, $name );
 147                 if ( !$title instanceof Title ) { // files have valid titles
 148                         wfForbidden( 'img-auth-accessdenied', 'img-auth-badtitle', $name );
 149                         return;
 150                 }
 151
 152                 // Run hook for extension authorization plugins
 153                 /** @var $result array */
 154                 $result = null;
 155                 if ( !wfRunHooks( 'ImgAuthBeforeStream', array( &$title, &$path, &$name, &$result ) ) ) {
 156                         wfForbidden( $result[0], $result[1], array_slice( $result, 2 ) );
 157                         return;
 158                 }
 159
 160                 // Check user authorization for this title
 161                 // Checks Whitelist too
 162                 if ( !$title->userCan( 'read' ) ) {
 163                         wfForbidden( 'img-auth-accessdenied', 'img-auth-noread', $name );
 164                         return;
 165                 }
 166         }
 167
 168         if ( $request->getCheck( 'download' ) ) {
 169                 $headers[] = 'Content-Disposition: attachment';
 170         }
 171
 172         // Stream the requested file
 173         wfDebugLog( 'img_auth', "Streaming `" . $filename . "`." );
 174         $repo->streamFile( $filename, $headers );
 175 }
 176
 177 /**
 178  * Issue a standard HTTP 403 Forbidden header ($msg1-a message index, not a message) and an
 179  * error message ($msg2, also a message index), (both required) then end the script
 180  * subsequent arguments to $msg2 will be passed as parameters only for replacing in $msg2
 181  * @param string $msg1
 182  * @param string $msg2
 183  */
 184 function wfForbidden( $msg1, $msg2 ) {
 185         global $wgImgAuthDetails;
 186
 187         $args = func_get_args();
 188         array_shift( $args );
 189         array_shift( $args );
 190         $args = ( isset( $args[0] ) && is_array( $args[0] ) ) ? $args[0] : $args;
 191
 192         $msgHdr = wfMessage( $msg1 )->escaped();
 193         $detailMsgKey = $wgImgAuthDetails ? $msg2 : 'badaccess-group0';
 194         $detailMsg = wfMessage( $detailMsgKey, $args )->escaped();
 195
 196         wfDebugLog( 'img_auth',
 197                 "wfForbidden Hdr: " . wfMessage( $msg1 )->inLanguage( 'en' )->text() . " Msg: " .
 198                         wfMessage( $msg2, $args )->inLanguage( 'en' )->text()
 199         );
 200
 201         header( 'HTTP/1.0 403 Forbidden' );
 202         header( 'Cache-Control: no-cache' );
 203         header( 'Content-Type: text/html; charset=utf-8' );
 204         echo <<<ENDS
 205 <html>
 206 <body>
 207 <h1>$msgHdr</h1>
 208 <p>$detailMsg</p>
 209 </body>
 210 </html>
 211 ENDS;
 212 }