wikimedia / mediawiki

img_auth.php

<?php

For compatibility and reusability of your code, PSR1 recommends that a file should introduce either new symbols (like classes, functions, etc.) or have side-effects (like outputting something, or including other files), but not both at the same time. The first symbol is defined on line 40 and the first side effect is on line 41.

/**
 * Image authorisation script
 *
 * To use this, see https://www.mediawiki.org/wiki/Manual:Image_Authorization
 *
 * - Set $wgUploadDirectory to a non-public directory (not web accessible)
 * - Set $wgUploadPath to point to this file
 *
 * Optional Parameters
 *
 * - Set $wgImgAuthDetails = true if you want the reason the access was denied messages to
 *       be displayed instead of just the 403 error (doesn't work on IE anyway),
 *       otherwise it will only appear in error logs
 *
 *  For security reasons, you usually don't want your user to know *why* access was denied,
 *  just that it was. If you want to change this, you can set $wgImgAuthDetails to 'true'
 *  in localsettings.php and it will give the user the reason why access was denied.
 *
 * Your server needs to support PATH_INFO; CGI-based configurations usually don't.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 */

define( 'MW_NO_OUTPUT_COMPRESSION', 1 );
require __DIR__ . '/includes/WebStart.php';

# Set action base paths so that WebRequest::getPathInfo()
# recognizes the "X" as the 'title' in ../img_auth.php/X urls.
$wgArticlePath = false; # Don't let a "/*" article path clober our action path
$wgActionPaths = [ "$wgUploadPath/" ];

wfImageAuthMain();

$mediawiki = new MediaWiki();
$mediawiki->doPostOutputShutdown( 'fast' );

function wfImageAuthMain() {
	global $wgImgAuthUrlPathMap;

	$request = RequestContext::getMain()->getRequest();
	$publicWiki = in_array( 'read', User::getGroupPermissions( [ '*' ] ), true );

	// Get the requested file path (source file or thumbnail)
	$matches = WebRequest::getPathInfo();
	if ( !isset( $matches['title'] ) ) {
		wfForbidden( 'img-auth-accessdenied', 'img-auth-nopathinfo' );
		return;
	}
	$path = $matches['title'];
	if ( $path && $path[0] !== '/' ) {
		// Make sure $path has a leading /
		$path = "/" . $path;
	}

	// Check for bug 28235: QUERY_STRING overriding the correct extension
	$whitelist = [];
	$extension = FileBackend::extensionFromPath( $path, 'rawcase' );
	if ( $extension != '' ) {
		$whitelist[] = $extension;
	}
	if ( !$request->checkUrlExtension( $whitelist ) ) {
		return;
	}

	// 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 = FileBackendGroup::singleton()->backendFromPath( $storageDir );
			$filename = $storageDir . substr( $path, strlen( $prefix ) ); // strip prefix
			// Check basic user authorization
			if ( !RequestContext::getMain()->getUser()->isAllowed( 'read' ) ) {
				wfForbidden( 'img-auth-accessdenied', 'img-auth-noread', $path );
				return;
			}
			if ( $be->fileExists( [ 'src' => $filename ] ) ) {
				wfDebugLog( 'img_auth', "Streaming `" . $filename . "`." );
				$be->streamFile( [ 'src' => $filename ],
					[ 'Cache-Control: private', 'Vary: Cookie' ] );
			} else {
				wfForbidden( 'img-auth-accessdenied', 'img-auth-nofile', $path );
			}
			return;
		}
	}

	// Get the local file repository
	$repo = RepoGroup::singleton()->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 ( substr( $path, 0, 9 ) === '/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

	if ( !$publicWiki ) {
		// For private wikis, run extra auth checks and set cache control headers
		$headers[] = 'Cache-Control: private';
		$headers[] = 'Vary: Cookie';

		$title = Title::makeTitleSafe( NS_FILE, $name );
		if ( !$title instanceof Title ) { // files have valid titles
			wfForbidden( 'img-auth-accessdenied', 'img-auth-badtitle', $name );
			return;
		}

		// Run hook for extension authorization plugins
		/** @var $result array */
		$result = null;
		if ( !Hooks::run( 'ImgAuthBeforeStream', [ &$title, &$path, &$name, &$result ] ) ) {
			wfForbidden( $result[0], $result[1], array_slice( $result, 2 ) );
			return;
		}

		// Check user authorization for this title
		// Checks Whitelist too
		if ( !$title->userCan( 'read' ) ) {
			wfForbidden( 'img-auth-accessdenied', 'img-auth-noread', $name );
			return;
		}
	}

	$options = []; // HTTP header options
	if ( isset( $_SERVER['HTTP_RANGE'] ) ) {
		$options['range'] = $_SERVER['HTTP_RANGE'];
	}
	if ( isset( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
		$options['if-modified-since'] = $_SERVER['HTTP_IF_MODIFIED_SINCE'];
	}

	if ( $request->getCheck( 'download' ) ) {
		$headers[] = 'Content-Disposition: attachment';
	}

	// Stream the requested file
	wfDebugLog( 'img_auth', "Streaming `" . $filename . "`." );
	$repo->streamFile( $filename, $headers, $options );
}

/**
 * Issue a standard HTTP 403 Forbidden header ($msg1-a message index, not a message) and an
 * error message ($msg2, also a message index), (both required) then end the script
 * subsequent arguments to $msg2 will be passed as parameters only for replacing in $msg2
 * @param string $msg1
 * @param string $msg2
 */
function wfForbidden( $msg1, $msg2 ) {
	global $wgImgAuthDetails;

	$args = func_get_args();
	array_shift( $args );
	array_shift( $args );
	$args = ( isset( $args[0] ) && is_array( $args[0] ) ) ? $args[0] : $args;

	$msgHdr = wfMessage( $msg1 )->escaped();
	$detailMsgKey = $wgImgAuthDetails ? $msg2 : 'badaccess-group0';
	$detailMsg = wfMessage( $detailMsgKey, $args )->escaped();

	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' );
	echo <<<ENDS
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8" />
<title>$msgHdr</title>
</head>
<body>
<h1>$msgHdr</h1>
<p>$detailMsg</p>
</body>
</html>
ENDS;
}