diff options
Diffstat (limited to 'includes/upload/UploadBase.php')
| -rw-r--r-- | includes/upload/UploadBase.php | 33 |
1 files changed, 14 insertions, 19 deletions
diff --git a/includes/upload/UploadBase.php b/includes/upload/UploadBase.php index 89ce2b3a..14959c26 100644 --- a/includes/upload/UploadBase.php +++ b/includes/upload/UploadBase.php @@ -1416,27 +1416,22 @@ abstract class UploadBase { } } - # href with embedded svg as target - if ( $stripped == 'href' && preg_match( '!data:[^,]*image/svg[^,]*,!sim', $value ) ) { - wfDebug( __METHOD__ . ": Found href to embedded svg " - . "\"<$strippedElement '$attrib'='$value'...\" in uploaded file.\n" ); - - return true; - } - - # href with embedded (text/xml) svg as target - if ( $stripped == 'href' && preg_match( '!data:[^,]*text/xml[^,]*,!sim', $value ) ) { - wfDebug( __METHOD__ . ": Found href to embedded svg " - . "\"<$strippedElement '$attrib'='$value'...\" in uploaded file.\n" ); - - return true; + # only allow data: targets that should be safe. This prevents vectors like, + # image/svg, text/xml, application/xml, and text/html, which can contain scripts + if ( $stripped == 'href' && strncasecmp( 'data:', $value, 5 ) === 0 ) { + // rfc2397 parameters. This is only slightly slower than (;[\w;]+)*. + $parameters = '(?>;[a-zA-Z0-9\!#$&\'*+.^_`{|}~-]+=(?>[a-zA-Z0-9\!#$&\'*+.^_`{|}~-]+|"(?>[\0-\x0c\x0e-\x21\x23-\x5b\x5d-\x7f]+|\\\\[\0-\x7f])*"))*(?:;base64)?'; + if ( !preg_match( "!^data:\s*image/(gif|jpeg|jpg|png)$parameters,!i", $value ) ) { + wfDebug( __METHOD__ . ": Found href to unwhitelisted data: uri " + . "\"<$strippedElement '$attrib'='$value'...\" in uploaded file.\n" ); + 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' + # Change href with animate from (http://html5sec.org/#137). + if ( $stripped === 'attributename' && $strippedElement === 'animate' - && !preg_match( '!^https?://!im', $value ) + && $this->stripXmlNamespace( $value ) == 'href' ) { wfDebug( __METHOD__ . ": Found animate that might be changing href using from " . "\"<$strippedElement '$attrib'='$value'...\" in uploaded file.\n" ); @@ -1528,7 +1523,7 @@ abstract class UploadBase { private static function checkCssFragment( $value ) { # Forbid external stylesheets, for both reliability and to protect viewer's privacy - if ( strpos( $value, '@import' ) !== false ) { + if ( stripos( $value, '@import' ) !== false ) { return true; } |