return null;
}
+ /** @var UploadBase $handler */
$handler = new $className;
$handler->initializeFromRequest( $request );
}
/**
- * Verify the mime type.
+ * Verify the MIME type.
*
- * @note Only checks that it is not an evil mime. The does it have
- * correct extension given its mime type check is in verifyFile.
- * @param string $mime Representing the mime
+ * @note Only checks that it is not an evil MIME. The "does it have
+ * correct extension given its MIME type?" check is in verifyFile.
+ * in `verifyFile()` that MIME type and file extension correlate.
+ * @param string $mime Representing the MIME
* @return mixed True if the file is verified, an array otherwise
*/
protected function verifyMimeType( $mime ) {
return array( 'filetype-badmime', $mime );
}
- # Check IE type
+ # Check what Internet Explorer would detect
$fp = fopen( $this->mTempPath, 'rb' );
$chunk = fread( $fp, 256 );
fclose( $fp );
$this->mFileProps = FSFile::getPropsFromPath( $this->mTempPath, $this->mFinalExtension );
- # check mime type, if desired
+ # check MIME type, if desired
$mime = $this->mFileProps['file-mime'];
$status = $this->verifyMimeType( $mime );
if ( $status !== true ) {
/**
* Return the local file and initializes if necessary.
*
- * @return LocalFile|null
+ * @return LocalFile|UploadStashFile|null
*/
public function getLocalFile() {
if ( is_null( $this->mLocalFile ) ) {
}
/**
- * Checks if the mime type of the uploaded file matches the file extension.
+ * Checks if the MIME type of the uploaded file matches the file extension.
*
- * @param string $mime The mime type of the uploaded file
+ * @param string $mime The MIME type of the uploaded file
* @param string $extension The filename extension that the file is to be served with
* @return bool
*/
* positives in some situations.
*
* @param string $file Pathname to the temporary upload file
- * @param string $mime The mime type of the file
+ * @param string $mime The MIME type of the file
* @param string $extension The extension of the file
* @return bool True if the file contains something looking like embedded scripts
*/
* @param array $attribs
* @return bool
*/
- public function checkSvgScriptCallback( $element, $attribs ) {
+ public function checkSvgScriptCallback( $element, $attribs, $data = null ) {
+
list( $namespace, $strippedElement ) = $this->splitXmlNamespace( $element );
// We specifically don't include:
return true;
}
+ # Check <style> css
+ if ( $strippedElement == 'style'
+ && self::checkCssFragment( Sanitizer::normalizeCss( $data ) )
+ ) {
+ wfDebug( __METHOD__ . ": hostile css in style element.\n" );
+ return true;
+ }
+
foreach ( $attribs as $attrib => $value ) {
$stripped = $this->stripXmlNamespace( $attrib );
$value = strtolower( $value );
return true;
}
+ # Change href with animate from (http://html5sec.org/#137). This doesn't seem
+ # possible without embedding the svg, but filter here in case.
+ if ( $stripped == 'from'
+ && $strippedElement === 'animate'
+ && !preg_match( '!^https?://!im', $value )
+ ) {
+ wfDebug( __METHOD__ . ": Found animate that might be changing href using from "
+ . "\"<$strippedElement '$attrib'='$value'...\" in uploaded file.\n" );
+
+ return true;
+ }
+
# use set/animate to add event-handler attribute to parent
if ( ( $strippedElement == 'set' || $strippedElement == 'animate' )
&& $stripped == 'attributename'
}
# use CSS styles to bring in remote code
- # catch url("http:..., url('http:..., url(http:..., but not url("#..., url('#..., url(#....
- $tagsList = "font|clip-path|fill|filter|marker|marker-end|marker-mid|marker-start|mask|stroke";
if ( $stripped == 'style'
- && preg_match_all(
- '!((?:' . $tagsList . ')\s*:\s*url\s*\(\s*["\']?\s*[^#]+.*?\))!sim',
- $value,
- $matches
- )
+ && self::checkCssFragment( Sanitizer::normalizeCss( $value ) )
) {
- foreach ( $matches[1] as $match ) {
- if ( !preg_match( '!(?:' . $tagsList . ')\s*:\s*url\s*\(\s*(#|\'#|"#)!sim', $match ) ) {
- wfDebug( __METHOD__ . ": Found svg setting a style with "
- . "remote url '$attrib'='$value' in uploaded file.\n" );
+ wfDebug( __METHOD__ . ": Found svg setting a style with "
+ . "remote url '$attrib'='$value' in uploaded file.\n" );
+ return true;
+ }
- return true;
- }
- }
+ # Several attributes can include css, css character escaping isn't allowed
+ $cssAttrs = array( 'font', 'clip-path', 'fill', 'filter', 'marker',
+ 'marker-end', 'marker-mid', 'marker-start', 'mask', 'stroke' );
+ if ( in_array( $stripped, $cssAttrs )
+ && self::checkCssFragment( $value )
+ ) {
+ wfDebug( __METHOD__ . ": Found svg setting a style with "
+ . "remote url '$attrib'='$value' in uploaded file.\n" );
+ return true;
}
# image filters can pull in url, which could be svg that executes scripts
return false; //No scripts detected
}
+ /**
+ * Check a block of CSS or CSS fragment for anything that looks like
+ * it is bringing in remote code.
+ * @param string $value a string of CSS
+ * @param bool $propOnly only check css properties (start regex with :)
+ * @return bool true if the CSS contains an illegal string, false if otherwise
+ */
+ private static function checkCssFragment( $value ) {
+
+ # Forbid external stylesheets, for both reliability and to protect viewer's privacy
+ if ( strpos( $value, '@import' ) !== false ) {
+ return true;
+ }
+
+ # We allow @font-face to embed fonts with data: urls, so we snip the string
+ # 'url' out so this case won't match when we check for urls below
+ $pattern = '!(@font-face\s*{[^}]*src:)url(\("data:;base64,)!im';
+ $value = preg_replace( $pattern, '$1$2', $value );
+
+ # Check for remote and executable CSS. Unlike in Sanitizer::checkCss, the CSS
+ # properties filter and accelerator don't seem to be useful for xss in SVG files.
+ # Expression and -o-link don't seem to work either, but filtering them here in case.
+ # Additionally, we catch remote urls like url("http:..., url('http:..., url(http:...,
+ # but not local ones such as url("#..., url('#..., url(#....
+ if ( preg_match( '!expression
+ | -o-link\s*:
+ | -o-link-source\s*:
+ | -o-replace\s*:!imx', $value ) ) {
+ return true;
+ }
+
+ if ( preg_match_all(
+ "!(\s*(url|image|image-set)\s*\(\s*[\"']?\s*[^#]+.*?\))!sim",
+ $value,
+ $matches
+ ) !== 0
+ ) {
+ # TODO: redo this in one regex. Until then, url("#whatever") matches the first
+ foreach ( $matches[1] as $match ) {
+ if ( !preg_match( "!\s*(url|image|image-set)\s*\(\s*(#|'#|\"#)!im", $match ) ) {
+ return true;
+ }
+ }
+ }
+
+ if ( preg_match( '/[\000-\010\013\016-\037\177]/', $value ) ) {
+ return true;
+ }
+
+ return false;
+ }
+
/**
* Divide the element name passed by the xml parser to the callback into URI and prifix.
- * @param string $name
+ * @param string $element
* @return array Containing the namespace URI and prefix
*/
private static function splitXmlNamespace( $element ) {
* Get the current status of a chunked upload (used for polling).
* The status will be read from the *current* user session.
* @param string $statusKey
- * @return array|bool
+ * @return Status[]|bool
*/
public static function getSessionStatus( $statusKey ) {
return isset( $_SESSION[self::SESSION_STATUS_KEY][$statusKey] )