Fix display issues with RTL control characters in post names, subjects, and filenames.

2 files changed, 34 insertions, 0 deletions

diff --git a/inc/display.php b/inc/display.php
index 57110224..ab96eb26 100644
--- a/inc/display.php
+++ b/inc/display.php
@@ -213,6 +213,39 @@ function truncate($body, $url, $max_lines = false, $max_chars = false) {
 	return $body;
 }
 
+function bidi_cleanup($str){
+	# Closes all embedded RTL and LTR unicode formatting blocks in a string so that
+	# it can be used inside another without controlling its direction.
+	# More info: http://www.iamcal.com/understanding-bidirectional-text/
+	#
+	# LRE - U+202A - 0xE2 0x80 0xAA
+	# RLE - U+202B - 0xE2 0x80 0xAB
+	# LRO - U+202D - 0xE2 0x80 0xAD
+	# RLO - U+202E - 0xE2 0x80 0xAE
+	#
+	# PDF - U+202C - 0xE2 0x80 0xAC
+	#
+	$explicits	= '\xE2\x80\xAA|\xE2\x80\xAB|\xE2\x80\xAD|\xE2\x80\xAE';
+	$pdf		= '\xE2\x80\xAC';
+
+	$stack = 0;
+	$str = preg_replace_callback("!(?<explicits>$explicits)|(?<pdf>$pdf)!", function($match) use (&$stack) {
+		if (isset($match['explicits']) && $match['explicits']) {
+			$stack++;
+		} else {
+			if ($stack)
+				$stack--;
+			else
+				return '';
+		}
+		return $match[0];
+	}, $str);
+	for ($i=0; $i<$stack; $i++){
+		$str .= "\xE2\x80\xAC";
+	}
+	return $str;
+}
+
 function secure_link_confirm($text, $title, $confirm_message, $href) {
 	global $config;
 
diff --git a/inc/lib/Twig/Extensions/Extension/Tinyboard.php b/inc/lib/Twig/Extensions/Extension/Tinyboard.php
index 0a128e7b..7592d1b4 100644
--- a/inc/lib/Twig/Extensions/Extension/Tinyboard.php
+++ b/inc/lib/Twig/Extensions/Extension/Tinyboard.php
@@ -25,6 +25,7 @@ class Twig_Extensions_Extension_Tinyboard extends Twig_Extension
 			'until' => new Twig_Filter_Function('until'),
 			'split' => new Twig_Filter_Function('twig_split_filter'),
 			'push' => new Twig_Filter_Function('twig_push_filter'),
+			'bidi_cleanup' => new Twig_Filter_Function('bidi_cleanup'),
 			'addslashes' => new Twig_Filter_Function('addslashes')
 		);
 	}