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  * - 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;
  56
  57         $request = RequestContext::getMain()->getRequest();
  58         $publicWiki = in_array( 'read', User::getGroupPermissions( array( '*' ) ), true );
  59
  60         // See if this is a public Wiki (no protections).
  61         if ( $wgImgAuthPublicTest && $publicWiki ) {
  62                 // This is a public wiki, so disable this script (for private wikis only)
  63                 wfForbidden( 'img-auth-accessdenied', 'img-auth-public' );
  64                 return;
  65         }
  66
  67         // Get the requested file path (source file or thumbnail)
  68         $matches = WebRequest::getPathInfo();
  69         if ( !isset( $matches['title'] ) ) {
  70                 wfForbidden( 'img-auth-accessdenied', 'img-auth-nopathinfo' );
  71                 return;
  72         }
  73         $path = $matches['title'];
  74         if ( $path && $path[0] !== '/' ) {
  75                 // Make sure $path has a leading /
  76                 $path = "/" . $path;
  77         }
  78
  79         // Check for bug 28235: QUERY_STRING overriding the correct extension
  80         $whitelist = array();
  81         $extension = FileBackend::extensionFromPath( $path );
  82         if ( $extension != '' ) {
  83                 $whitelist[] = $extension;
  84         }
  85         if ( !$request->checkUrlExtension( $whitelist ) ) {
  86                 return;
  87         }
  88
  89         // Various extensions may have their own backends that need access.
  90         // Check if there is a special backend and storage base path for this file.
  91         foreach ( $wgImgAuthUrlPathMap as $prefix => $storageDir ) {
  92                 $prefix = rtrim( $prefix, '/' ) . '/'; // implicit trailing slash
  93                 if ( strpos( $path, $prefix ) === 0 ) {
  94                         $be = FileBackendGroup::singleton()->backendFromPath( $storageDir );
  95                         $filename = $storageDir . substr( $path, strlen( $prefix ) ); // strip prefix
  96                         // Check basic user authorization
  97                         if ( !RequestContext::getMain()->getUser()->isAllowed( 'read' ) ) {
  98                                 wfForbidden( 'img-auth-accessdenied', 'img-auth-noread', $path );
  99                                 return;
 100                         }
 101                         if ( $be->fileExists( array( 'src' => $filename ) ) ) {
 102                                 wfDebugLog( 'img_auth', "Streaming `" . $filename . "`." );
 103                                 $be->streamFile( array( 'src' => $filename ),
 104                                         array( 'Cache-Control: private', 'Vary: Cookie' ) );
 105                         } else {
 106                                 wfForbidden( 'img-auth-accessdenied', 'img-auth-nofile', $path );
 107                         }
 108                         return;
 109                 }
 110         }
 111
 112         // Get the local file repository
 113         $repo = RepoGroup::singleton()->getRepo( 'local' );
 114
 115         // Get the full file storage path and extract the source file name.
 116         // (e.g. 120px-Foo.png => Foo.png or page2-120px-Foo.png => Foo.png).
 117         // This only applies to thumbnails, and all thumbnails should
 118         // be under a folder that has the source file name.
 119         if ( strpos( $path, '/thumb/' ) === 0 ) {
 120                 $name = wfBaseName( dirname( $path ) ); // file is a thumbnail
 121                 $filename = $repo->getZonePath( 'thumb' ) . substr( $path, 6 ); // strip "/thumb"
 122                 // Check to see if the file exists
 123                 if ( !$repo->fileExists( $filename ) ) {
 124                         wfForbidden( 'img-auth-accessdenied', 'img-auth-nofile', $filename );
 125                         return;
 126                 }
 127         } else {
 128                 $name = wfBaseName( $path ); // file is a source file
 129                 $filename = $repo->getZonePath( 'public' ) . $path;
 130                 // Check to see if the file exists and is not deleted
 131                 $bits = explode( '!', $name, 2 );
 132                 if ( substr( $path, 0, 9 ) === '/archive/' && count( $bits ) == 2 ) {
 133                         $file = $repo->newFromArchiveName( $bits[1], $name );
 134                 } else {
 135                         $file = $repo->newFile( $name );
 136                 }
 137                 if ( !$file->exists() || $file->isDeleted( File::DELETED_FILE ) ) {
 138                         wfForbidden( 'img-auth-accessdenied', 'img-auth-nofile', $filename );
 139                         return;
 140                 }
 141         }
 142
 143         $headers = array(); // extra HTTP headers to send
 144
 145         if ( !$publicWiki ) {
 146                 // For private wikis, run extra auth checks and set cache control headers
 147                 $headers[] = 'Cache-Control: private';
 148                 $headers[] = 'Vary: Cookie';
 149
 150                 $title = Title::makeTitleSafe( NS_FILE, $name );
 151                 if ( !$title instanceof Title ) { // files have valid titles
 152                         wfForbidden( 'img-auth-accessdenied', 'img-auth-badtitle', $name );
 153                         return;
 154                 }
 155
 156                 // Run hook for extension authorization plugins
 157                 /** @var $result array */
 158                 $result = null;
 159                 if ( !wfRunHooks( 'ImgAuthBeforeStream', array( &$title, &$path, &$name, &$result ) ) ) {
 160                         wfForbidden( $result[0], $result[1], array_slice( $result, 2 ) );
 161                         return;
 162                 }
 163
 164                 // Check user authorization for this title
 165                 // Checks Whitelist too
 166                 if ( !$title->userCan( 'read' ) ) {
 167                         wfForbidden( 'img-auth-accessdenied', 'img-auth-noread', $name );
 168                         return;
 169                 }
 170         }
 171
 172         if ( $request->getCheck( 'download' ) ) {
 173                 $headers[] = 'Content-Disposition: attachment';
 174         }
 175
 176         // Stream the requested file
 177         wfDebugLog( 'img_auth', "Streaming `" . $filename . "`." );
 178         $repo->streamFile( $filename, $headers );
 179 }
 180
 181 /**
 182  * Issue a standard HTTP 403 Forbidden header ($msg1-a message index, not a message) and an
 183  * error message ($msg2, also a message index), (both required) then end the script
 184  * subsequent arguments to $msg2 will be passed as parameters only for replacing in $msg2
 185  * @param string $msg1
 186  * @param string $msg2
 187  */
 188 function wfForbidden( $msg1, $msg2 ) {
 189         global $wgImgAuthDetails;
 190
 191         $args = func_get_args();
 192         array_shift( $args );
 193         array_shift( $args );
 194         $args = ( isset( $args[0] ) && is_array( $args[0] ) ) ? $args[0] : $args;
 195
 196         $msgHdr = wfMessage( $msg1 )->escaped();
 197         $detailMsgKey = $wgImgAuthDetails ? $msg2 : 'badaccess-group0';
 198         $detailMsg = wfMessage( $detailMsgKey, $args )->escaped();
 199
 200         wfDebugLog( 'img_auth',
 201                 "wfForbidden Hdr: " . wfMessage( $msg1 )->inLanguage( 'en' )->text() . " Msg: " .
 202                         wfMessage( $msg2, $args )->inLanguage( 'en' )->text()
 203         );
 204
 205         header( 'HTTP/1.0 403 Forbidden' );
 206         header( 'Cache-Control: no-cache' );
 207         header( 'Content-Type: text/html; charset=utf-8' );
 208         echo <<<ENDS
 209 <html>
 210 <body>
 211 <h1>$msgHdr</h1>
 212 <p>$detailMsg</p>
 213 </body>
 214 </html>
 215 ENDS;
 216 }