From da4e30ec9d9729903c9c438fd76ef0fad303d1bc Mon Sep 17 00:00:00 2001 From: Brian Wolff Date: Sun, 24 Sep 2017 00:57:05 +0000 Subject: [PATCH] SECURITY: Ensure Message::rawParams can't lead to XSS If you used wfMessage( 'foo' )->rawParams( 'bar"baz' ) there's a possibility of leading to xss, if the foo message has a $1 in an attribute, as the quote characters may end the attribute. To prevent that, we convert $1 to $'"1 for after parameters, so if any of them end up in attributes, the attribute escaping will break the parameter name, preventing substitution. This would of course break if someone intentionally inserted a raw parameter into an attribute, but that's silly and I don't think we should allow that. This is similar to the parser strip marker issue. Bug: T176247 Change-Id: If83aec01b20e414f9c92be894f145d7df2974866 --- includes/Message.php | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) diff --git a/includes/Message.php b/includes/Message.php index 303a4b954e..d0f3e78358 100644 --- a/includes/Message.php +++ b/includes/Message.php @@ -1064,11 +1064,29 @@ class Message implements MessageSpecifier, Serializable { * @return string */ protected function replaceParameters( $message, $type = 'before' ) { + // A temporary marker for $1 parameters that is only valid + // in non-attribute contexts. However if the entire message is escaped + // then we don't want to use it because it will be mangled in all contexts + // and its unnessary as ->escaped() messages aren't html. + $marker = $format === self::FORMAT_ESCAPED ? '$' : '$\'"'; $replacementKeys = []; foreach ( $this->parameters as $n => $param ) { list( $paramType, $value ) = $this->extractParam( $param ); - if ( $type === $paramType ) { - $replacementKeys['$' . ( $n + 1 )] = $value; + if ( $type === 'before' ) { + if ( $paramType === 'before' ) { + $replacementKeys['$' . ( $n + 1 )] = $value; + } else /* $paramType === 'after' */ { + // To protect against XSS from replacing parameters + // inside html attributes, we convert $1 to $'"1. + // In the event that one of the parameters ends up + // in an attribute, either the ' or the " will be + // escaped, breaking the replacement and avoiding XSS. + $replacementKeys['$' . ( $n + 1 )] = $marker . ( $n + 1 ); + } + } else { + if ( $paramType === 'after' ) { + $replacementKeys[$marker . ( $n + 1 )] = $value; + } } } $message = strtr( $message, $replacementKeys ); -- 2.14.1