StreamFile.php

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<?php
 
use MediaWiki\MediaWikiServices;
 
class StreamFile {
    // Do not send any HTTP headers unless requested by caller (e.g. body only)
    public const STREAM_HEADLESS = HTTPFileStreamer::STREAM_HEADLESS;
    // Do not try to tear down any PHP output buffers
    public const STREAM_ALLOW_OB = HTTPFileStreamer::STREAM_ALLOW_OB;
 
    public static function stream(
        $fname, $headers = [], $sendErrors = true, $optHeaders = [], $flags = 0
    ) {
        if ( FileBackend::isStoragePath( $fname ) ) {
            throw new InvalidArgumentException( __FUNCTION__ . " given storage path '$fname'." );
        }
 
        $streamer = new HTTPFileStreamer(
            $fname,
            [
                'obResetFunc' => 'wfResetOutputBuffers',
                'streamMimeFunc' => [ __CLASS__, 'contentTypeFromPath' ]
            ]
        );
 
        return $streamer->stream( $headers, $sendErrors, $optHeaders, $flags );
    }
 
    public static function contentTypeFromPath( $filename, $safe = true ) {
        $trivialMimeDetection = MediaWikiServices::getInstance()->getMainConfig()->get( 'TrivialMimeDetection' );
 
        $ext = strrchr( $filename, '.' );
        $ext = $ext ? strtolower( substr( $ext, 1 ) ) : '';
 
        # trivial detection by file extension,
        # used for thumbnails (thumb.php)
        if ( $trivialMimeDetection ) {
            switch ( $ext ) {
                case 'gif':
                    return 'image/gif';
                case 'png':
                    return 'image/png';
                case 'jpg':
                case 'jpeg':
                    return 'image/jpeg';
            }
 
            return 'unknown/unknown';
        }
 
        $magic = MediaWikiServices::getInstance()->getMimeAnalyzer();
        // Use the extension only, rather than magic numbers, to avoid opening
        // up vulnerabilities due to uploads of files with allowed extensions
        // but disallowed types.
        $type = $magic->getMimeTypeFromExtensionOrNull( $ext );
 
        if ( $safe ) {
            $mainConfig = MediaWikiServices::getInstance()->getMainConfig();
            $prohibitedFileExtensions = $mainConfig->get( 'ProhibitedFileExtensions' );
            $checkFileExtensions = $mainConfig->get( 'CheckFileExtensions' );
            $strictFileExtensions = $mainConfig->get( 'StrictFileExtensions' );
            $fileExtensions = $mainConfig->get( 'FileExtensions' );
            $verifyMimeType = $mainConfig->get( 'VerifyMimeType' );
            $mimeTypeExclusions = $mainConfig->get( 'MimeTypeExclusions' );
            list( , $extList ) = UploadBase::splitExtensions( $filename );
            if ( UploadBase::checkFileExtensionList( $extList, $prohibitedFileExtensions ) ) {
                return 'unknown/unknown';
            }
            if ( $checkFileExtensions && $strictFileExtensions
                && !UploadBase::checkFileExtensionList( $extList, $fileExtensions )
            ) {
                return 'unknown/unknown';
            }
            if ( $verifyMimeType && in_array( strtolower( $type ), $mimeTypeExclusions ) ) {
                return 'unknown/unknown';
            }
        }
        return $type;
    }
}