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 // Commit and close up!
  54 $factory = wfGetLBFactory();
  55 $factory->commitMasterChanges();
  56 $factory->shutdown();
  57
  58 function wfImageAuthMain() {
  59         global $wgImgAuthPublicTest, $wgImgAuthUrlPathMap;
  60
  61         $request = RequestContext::getMain()->getRequest();
  62         $publicWiki = in_array( 'read', User::getGroupPermissions( array( '*' ) ), true );
  63
  64         // See if this is a public Wiki (no protections).
  65         if ( $wgImgAuthPublicTest && $publicWiki ) {
  66                 // This is a public wiki, so disable this script (for private wikis only)
  67                 wfForbidden( 'img-auth-accessdenied', 'img-auth-public' );
  68                 return;
  69         }
  70
  71         // Get the requested file path (source file or thumbnail)
  72         $matches = WebRequest::getPathInfo();
  73         if ( !isset( $matches['title'] ) ) {
  74                 wfForbidden( 'img-auth-accessdenied', 'img-auth-nopathinfo' );
  75                 return;
  76         }
  77         $path = $matches['title'];
  78         if ( $path && $path[0] !== '/' ) {
  79                 // Make sure $path has a leading /
  80                 $path = "/" . $path;
  81         }
  82
  83         // Check for bug 28235: QUERY_STRING overriding the correct extension
  84         $whitelist = array();
  85         $extension = FileBackend::extensionFromPath( $path );
  86         if ( $extension != '' ) {
  87                 $whitelist[] = $extension;
  88         }
  89         if ( !$request->checkUrlExtension( $whitelist ) ) {
  90                 return;
  91         }
  92
  93         // Various extensions may have their own backends that need access.
  94         // Check if there is a special backend and storage base path for this file.
  95         foreach ( $wgImgAuthUrlPathMap as $prefix => $storageDir ) {
  96                 $prefix = rtrim( $prefix, '/' ) . '/'; // implicit trailing slash
  97                 if ( strpos( $path, $prefix ) === 0 ) {
  98                         $be = FileBackendGroup::singleton()->backendFromPath( $storageDir );
  99                         $filename = $storageDir . substr( $path, strlen( $prefix ) ); // strip prefix
 100                         // Check basic user authorization
 101                         if ( !RequestContext::getMain()->getUser()->isAllowed( 'read' ) ) {
 102                                 wfForbidden( 'img-auth-accessdenied', 'img-auth-noread', $path );
 103                                 return;
 104                         }
 105                         if ( $be->fileExists( array( 'src' => $filename ) ) ) {
 106                                 wfDebugLog( 'img_auth', "Streaming `" . $filename . "`." );
 107                                 $be->streamFile( array( 'src' => $filename ),
 108                                         array( 'Cache-Control: private', 'Vary: Cookie' ) );
 109                         } else {
 110                                 wfForbidden( 'img-auth-accessdenied', 'img-auth-nofile', $path );
 111                         }
 112                         return;
 113                 }
 114         }
 115
 116         // Get the local file repository
 117         $repo = RepoGroup::singleton()->getRepo( 'local' );
 118
 119         // Get the full file storage path and extract the source file name.
 120         // (e.g. 120px-Foo.png => Foo.png or page2-120px-Foo.png => Foo.png).
 121         // This only applies to thumbnails, and all thumbnails should
 122         // be under a folder that has the source file name.
 123         if ( strpos( $path, '/thumb/' ) === 0 ) {
 124                 $name = wfBaseName( dirname( $path ) ); // file is a thumbnail
 125                 $filename = $repo->getZonePath( 'thumb' ) . substr( $path, 6 ); // strip "/thumb"
 126                 // Check to see if the file exists
 127                 if ( !$repo->fileExists( $filename ) ) {
 128                         wfForbidden( 'img-auth-accessdenied', 'img-auth-nofile', $filename );
 129                         return;
 130                 }
 131         } else {
 132                 $name = wfBaseName( $path ); // file is a source file
 133                 $filename = $repo->getZonePath( 'public' ) . $path;
 134                 // Check to see if the file exists and is not deleted
 135                 $bits = explode( '!', $name, 2 );
 136                 if ( substr( $path, 0, 9 ) === '/archive/' && count( $bits ) == 2 ) {
 137                         $file = $repo->newFromArchiveName( $bits[1], $name );
 138                 } else {
 139                         $file = $repo->newFile( $name );
 140                 }
 141                 if ( !$file->exists() || $file->isDeleted( File::DELETED_FILE ) ) {
 142                         wfForbidden( 'img-auth-accessdenied', 'img-auth-nofile', $filename );
 143                         return;
 144                 }
 145         }
 146
 147         $headers = array(); // extra HTTP headers to send
 148
 149         if ( !$publicWiki ) {
 150                 // For private wikis, run extra auth checks and set cache control headers
 151                 $headers[] = 'Cache-Control: private';
 152                 $headers[] = 'Vary: Cookie';
 153
 154                 $title = Title::makeTitleSafe( NS_FILE, $name );
 155                 if ( !$title instanceof Title ) { // files have valid titles
 156                         wfForbidden( 'img-auth-accessdenied', 'img-auth-badtitle', $name );
 157                         return;
 158                 }
 159
 160                 // Run hook for extension authorization plugins
 161                 /** @var $result array */
 162                 $result = null;
 163                 if ( !wfRunHooks( 'ImgAuthBeforeStream', array( &$title, &$path, &$name, &$result ) ) ) {
 164                         wfForbidden( $result[0], $result[1], array_slice( $result, 2 ) );
 165                         return;
 166                 }
 167
 168                 // Check user authorization for this title
 169                 // Checks Whitelist too
 170                 if ( !$title->userCan( 'read' ) ) {
 171                         wfForbidden( 'img-auth-accessdenied', 'img-auth-noread', $name );
 172                         return;
 173                 }
 174         }
 175
 176         if ( $request->getCheck( 'download' ) ) {
 177                 $headers[] = 'Content-Disposition: attachment';
 178         }
 179
 180         // Stream the requested file
 181         wfDebugLog( 'img_auth', "Streaming `" . $filename . "`." );
 182         $repo->streamFile( $filename, $headers );
 183 }
 184
 185 /**
 186  * Issue a standard HTTP 403 Forbidden header ($msg1-a message index, not a message) and an
 187  * error message ($msg2, also a message index), (both required) then end the script
 188  * subsequent arguments to $msg2 will be passed as parameters only for replacing in $msg2
 189  * @param string $msg1
 190  * @param string $msg2
 191  */
 192 function wfForbidden( $msg1, $msg2 ) {
 193         global $wgImgAuthDetails;
 194
 195         $args = func_get_args();
 196         array_shift( $args );
 197         array_shift( $args );
 198         $args = ( isset( $args[0] ) && is_array( $args[0] ) ) ? $args[0] : $args;
 199
 200         $msgHdr = wfMessage( $msg1 )->escaped();
 201         $detailMsgKey = $wgImgAuthDetails ? $msg2 : 'badaccess-group0';
 202         $detailMsg = wfMessage( $detailMsgKey, $args )->escaped();
 203
 204         wfDebugLog( 'img_auth',
 205                 "wfForbidden Hdr: " . wfMessage( $msg1 )->inLanguage( 'en' )->text() . " Msg: " .
 206                         wfMessage( $msg2, $args )->inLanguage( 'en' )->text()
 207         );
 208
 209         header( 'HTTP/1.0 403 Forbidden' );
 210         header( 'Cache-Control: no-cache' );
 211         header( 'Content-Type: text/html; charset=utf-8' );
 212         echo <<<ENDS
 213 <html>
 214 <body>
 215 <h1>$msgHdr</h1>
 216 <p>$detailMsg</p>
 217 </body>
 218 </html>
 219 ENDS;
 220 }