img_auth.php

<?php

/**
 * Image authorisation script
 *
 * To use this, see http://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
 * - Set $wgImgAuthPublicTest false if you don't want to just check and see if all are public
 *       must be set to false if using specific restrictions such as LockDown or NSFileRepo
 *
 *  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.
 *
 * @file
 *
 **/

define( 'MW_NO_OUTPUT_COMPRESSION', 1 );
if ( isset( $_SERVER['MW_COMPILED'] ) ) {
    require ( 'phase3/includes/WebStart.php' );
} else {
    require ( dirname( __FILE__ ) . '/includes/WebStart.php' );
}
wfProfileIn( 'img_auth.php' );

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

wfImageAuthMain();
wfLogProfilingData();

function wfImageAuthMain() {
    global $wgImgAuthPublicTest, $wgRequest, $wgUploadDirectory;

    // See if this is a public Wiki (no protections).
    if ( $wgImgAuthPublicTest
        && in_array( 'read', User::getGroupPermissions( array( '*' ) ), true ) )
    {
        // This is a public wiki, so disable this script (for private wikis only)
        wfForbidden( 'img-auth-accessdenied', 'img-auth-public' );
        return;
    }

    // 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 = array();
    $dotPos = strrpos( $path, '.' );
    if ( $dotPos !== false ) {
        $whitelist[] = substr( $path, $dotPos + 1 );
    }
    if ( !$wgRequest->checkUrlExtension( $whitelist ) ) {
        return;
    }

    // Get the local file repository
    $repo = RepoGroup::singleton()->getRepo( 'local' );

    // 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, and all thumbnails should
    // be under a folder that has the source file name.
    if ( strpos( $path, '/thumb/' ) === 0 ) {
        $name = wfBaseName( dirname( $path ) ); // file is a thumbnail
        $filename = $repo->getZonePath( 'thumb' ) . substr( $path, 6 ); // strip "/thumb"
    } else {
        $name = wfBaseName( $path ); // file is a source file
        $filename = $repo->getZonePath( 'public' ) . $path;
    }

    // Check to see if the file exists
    if ( !$repo->fileExists( $filename, FileRepo::FILES_ONLY ) ) {
        wfForbidden( 'img-auth-accessdenied','img-auth-nofile', $filename );
        return;
    }

    $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
    if ( !wfRunHooks( 'ImgAuthBeforeStream', array( &$title, &$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;
    }

    // Stream the requested file
    wfDebugLog( 'img_auth', "Streaming `".$filename."`." );
    $repo->streamFile( $filename, array( 'Cache-Control: private', 'Vary: Cookie' ) );
}

/**
 * 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 $msg1
 * @param $msg2
 */
function wfForbidden( $msg1, $msg2 ) {
    global $wgImgAuthDetails;

    $args = func_get_args();
    array_shift( $args );
    array_shift( $args );

    $msgHdr = htmlspecialchars( wfMsg( $msg1 ) );
    $detailMsgKey = $wgImgAuthDetails ? $msg2 : 'badaccess-group0';
    $detailMsg = htmlspecialchars( wfMsg( $detailMsgKey, $args ) );

    wfDebugLog( 'img_auth',
        "wfForbidden Hdr:" . wfMsgExt( $msg1, array( 'language' => 'en' ) ). " Msg: ".
        wfMsgExt( $msg2, array( 'language' => 'en' ), $args )
    );

    header( 'HTTP/1.0 403 Forbidden' );
    header( 'Cache-Control: no-cache' );
    header( 'Content-Type: text/html; charset=utf-8' );
    echo <<<ENDS
<html>
<body>
<h1>$msgHdr</h1>
<p>$detailMsg</p>
</body>
</html>
ENDS;
}