img_auth.php

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<?php
use MediaWiki\HookContainer\HookRunner;
use MediaWiki\Html\TemplateParser;
use MediaWiki\Request\WebRequest;
use MediaWiki\Title\Title;
 
define( 'MW_NO_OUTPUT_COMPRESSION', 1 );
define( 'MW_ENTRY_POINT', 'img_auth' );
require __DIR__ . '/includes/WebStart.php';
 
wfImageAuthMain();
 
$mediawiki = new MediaWiki();
$mediawiki->doPostOutputShutdown();
 
function wfImageAuthMain() {
    global $wgImgAuthUrlPathMap, $wgScriptPath, $wgImgAuthPath;
 
    $services = \MediaWiki\MediaWikiServices::getInstance();
    $permissionManager = $services->getPermissionManager();
 
    $request = RequestContext::getMain()->getRequest();
    $publicWiki = $services->getGroupPermissionsLookup()->groupHasPermission( '*', 'read' );
 
    // Find the path assuming the request URL is relative to the local public zone URL
    $baseUrl = $services->getRepoGroup()->getLocalRepo()->getZoneUrl( 'public' );
    if ( $baseUrl[0] === '/' ) {
        $basePath = $baseUrl;
    } else {
        $basePath = parse_url( $baseUrl, PHP_URL_PATH );
    }
    $path = WebRequest::getRequestPathSuffix( $basePath );
 
    if ( $path === false ) {
        // Try instead assuming img_auth.php is the base path
        $basePath = $wgImgAuthPath ?: "$wgScriptPath/img_auth.php";
        $path = WebRequest::getRequestPathSuffix( $basePath );
    }
 
    if ( $path === false ) {
        wfForbidden( 'img-auth-accessdenied', 'img-auth-notindir' );
        return;
    }
 
    if ( $path === '' || $path[0] !== '/' ) {
        // Make sure $path has a leading /
        $path = "/" . $path;
    }
 
    $user = RequestContext::getMain()->getUser();
 
    // Various extensions may have their own backends that need access.
    // Check if there is a special backend and storage base path for this file.
    foreach ( $wgImgAuthUrlPathMap as $prefix => $storageDir ) {
        $prefix = rtrim( $prefix, '/' ) . '/'; // implicit trailing slash
        if ( strpos( $path, $prefix ) === 0 ) {
            $be = $services->getFileBackendGroup()->backendFromPath( $storageDir );
            $filename = $storageDir . substr( $path, strlen( $prefix ) ); // strip prefix
            // Check basic user authorization
            $isAllowedUser = $permissionManager->userHasRight( $user, 'read' );
            if ( !$isAllowedUser ) {
                wfForbidden( 'img-auth-accessdenied', 'img-auth-noread', $path );
                return;
            }
            if ( $be->fileExists( [ 'src' => $filename ] ) ) {
                wfDebugLog( 'img_auth', "Streaming `" . $filename . "`." );
                $be->streamFile( [
                    'src' => $filename,
                    'headers' => [ 'Cache-Control: private', 'Vary: Cookie' ]
                ] );
            } else {
                wfForbidden( 'img-auth-accessdenied', 'img-auth-nofile', $path );
            }
            return;
        }
    }
 
    // Get the local file repository
    $repo = $services->getRepoGroup()->getRepo( 'local' );
    $zone = strstr( ltrim( $path, '/' ), '/', true );
 
    // Get the full file storage path and extract the source file name.
    // (e.g. 120px-Foo.png => Foo.png or page2-120px-Foo.png => Foo.png).
    // This only applies to thumbnails/transcoded, and each of them should
    // be under a folder that has the source file name.
    if ( $zone === 'thumb' || $zone === 'transcoded' ) {
        $name = wfBaseName( dirname( $path ) );
        $filename = $repo->getZonePath( $zone ) . substr( $path, strlen( "/" . $zone ) );
        // Check to see if the file exists
        if ( !$repo->fileExists( $filename ) ) {
            wfForbidden( 'img-auth-accessdenied', 'img-auth-nofile', $filename );
            return;
        }
    } else {
        $name = wfBaseName( $path ); // file is a source file
        $filename = $repo->getZonePath( 'public' ) . $path;
        // Check to see if the file exists and is not deleted
        $bits = explode( '!', $name, 2 );
        if ( str_starts_with( $path, '/archive/' ) && count( $bits ) == 2 ) {
            $file = $repo->newFromArchiveName( $bits[1], $name );
        } else {
            $file = $repo->newFile( $name );
        }
        if ( !$file->exists() || $file->isDeleted( File::DELETED_FILE ) ) {
            wfForbidden( 'img-auth-accessdenied', 'img-auth-nofile', $filename );
            return;
        }
    }
 
    $headers = []; // extra HTTP headers to send
 
    $title = Title::makeTitleSafe( NS_FILE, $name );
 
    $hookRunner = new HookRunner( $services->getHookContainer() );
    if ( !$publicWiki ) {
        // For private wikis, run extra auth checks and set cache control headers
        $headers['Cache-Control'] = 'private';
        $headers['Vary'] = 'Cookie';
 
        if ( !$title instanceof Title ) { // files have valid titles
            wfForbidden( 'img-auth-accessdenied', 'img-auth-badtitle', $name );
            return;
        }
 
        // Run hook for extension authorization plugins
        $result = null;
        if ( !$hookRunner->onImgAuthBeforeStream( $title, $path, $name, $result ) ) {
            wfForbidden( $result[0], $result[1], array_slice( $result, 2 ) );
            return;
        }
 
        // Check user authorization for this title
        // Checks Whitelist too
 
        if ( !$permissionManager->userCan( 'read', $user, $title ) ) {
            wfForbidden( 'img-auth-accessdenied', 'img-auth-noread', $name );
            return;
        }
    }
 
    if ( isset( $_SERVER['HTTP_RANGE'] ) ) {
        $headers['Range'] = $_SERVER['HTTP_RANGE'];
    }
    if ( isset( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
        $headers['If-Modified-Since'] = $_SERVER['HTTP_IF_MODIFIED_SINCE'];
    }
 
    if ( $request->getCheck( 'download' ) ) {
        $headers['Content-Disposition'] = 'attachment';
    }
 
    // Allow modification of headers before streaming a file
    $hookRunner->onImgAuthModifyHeaders( $title->getTitleValue(), $headers );
 
    // Stream the requested file
    [ $headers, $options ] = HTTPFileStreamer::preprocessHeaders( $headers );
    wfDebugLog( 'img_auth', "Streaming `" . $filename . "`." );
    $repo->streamFileWithStatus( $filename, $headers, $options );
}
 
function wfForbidden( $msg1, $msg2, ...$args ) {
    global $wgImgAuthDetails;
 
    $args = ( isset( $args[0] ) && is_array( $args[0] ) ) ? $args[0] : $args;
 
    $msgHdr = wfMessage( $msg1 )->text();
    $detailMsgKey = $wgImgAuthDetails ? $msg2 : 'badaccess-group0';
    $detailMsg = wfMessage( $detailMsgKey, $args )->text();
 
    wfDebugLog( 'img_auth',
        "wfForbidden Hdr: " . wfMessage( $msg1 )->inLanguage( 'en' )->text() . " Msg: " .
            wfMessage( $msg2, $args )->inLanguage( 'en' )->text()
    );
 
    HttpStatus::header( 403 );
    header( 'Cache-Control: no-cache' );
    header( 'Content-Type: text/html; charset=utf-8' );
    $templateParser = new TemplateParser();
    echo $templateParser->processTemplate( 'ImageAuthForbidden', [
        'msgHdr' => $msgHdr,
        'detailMsg' => $detailMsg,
    ] );
}