Merge branch '4593-18' into 1.8

2 files changed, 48 insertions, 6 deletions

diff --git a/engine/lib/output.php b/engine/lib/output.php
index 0069360f0..352de863b 100644
--- a/engine/lib/output.php
+++ b/engine/lib/output.php
@@ -398,3 +398,45 @@ function elgg_strip_tags($string) {
 
 	return $string;
 }
+
+/**
+ * Apply html_entity_decode() to a string while re-entitising HTML
+ * special char entities to prevent them from being decoded back to their
+ * unsafe original forms.
+ *
+ * This relies on html_entity_decode() not translating entities when
+ * doing so leaves behind another entity, e.g. > if decoded would
+ * create > which is another entity itself. This seems to escape the
+ * usual behaviour where any two paired entities creating a HTML tag are
+ * usually decoded, i.e. a lone > is not decoded, but <foo> would
+ * be decoded to <foo> since it creates a full tag.
+ *
+ * Note: This function is poorly explained in the manual - which is really
+ * bad given its potential for misuse on user input already escaped elsewhere.
+ * Stackoverflow is littered with advice to use this function in the precise
+ * way that would lead to user input being capable of injecting arbitrary HTML.
+ *
+ * @param string $string
+ *
+ * @return string
+ *
+ * @author Pádraic Brady
+ * @copyright Copyright (c) 2010 Pádraic Brady (http://blog.astrumfutura.com)
+ * @license Released under dual-license GPL2/MIT by explicit permission of Pádraic Brady
+ *
+ * @access private
+ */
+function _elgg_html_decode($string) {
+	$string = str_replace(
+		array('&gt;', '&lt;', '&amp;', '&quot;', '&#039;'),
+		array('&amp;gt;', '&amp;lt;', '&amp;amp;', '&amp;quot;', '&amp;#039;'),
+		$string
+	);
+	$string = html_entity_decode($string, ENT_NOQUOTES, 'UTF-8');
+	$string = str_replace(
+		array('&amp;gt;', '&amp;lt;', '&amp;amp;', '&amp;quot;', '&amp;#039;'),
+		array('&gt;', '&lt;', '&amp;', '&quot;', '&#039;'),
+		$string
+	);
+	return $string;
+}
diff --git a/engine/lib/upgrades/2010052601.php b/engine/lib/upgrades/2010052601.php
index 5b477910f..a9cca6dc5 100644
--- a/engine/lib/upgrades/2010052601.php
+++ b/engine/lib/upgrades/2010052601.php
@@ -9,14 +9,14 @@ $params = array('type' => 'group',
 $groups = elgg_get_entities($params);
 if ($groups) {
 	foreach ($groups as $group) {
-		$group->name = html_entity_decode($group->name, ENT_COMPAT, 'UTF-8');
-		$group->description = html_entity_decode($group->description, ENT_COMPAT, 'UTF-8');
-		$group->briefdescription = html_entity_decode($group->briefdescription, ENT_COMPAT, 'UTF-8');
-		$group->website = html_entity_decode($group->website, ENT_COMPAT, 'UTF-8');
+		$group->name = _elgg_html_decode($group->name);
+		$group->description = _elgg_html_decode($group->description);
+		$group->briefdescription = _elgg_html_decode($group->briefdescription);
+		$group->website = _elgg_html_decode($group->website);
 		if ($group->interests) {
 			$tags = $group->interests;
-			foreach ($tags as $index=>$tag) {
-				$tags[$index] = html_entity_decode($tag, ENT_COMPAT, 'UTF-8');
+			foreach ($tags as $index => $tag) {
+				$tags[$index] = _elgg_html_decode($tag);
 			}
 			$group->interests = $tags;
 		}