ext/dom: use-after-free via DOMNameSpaceNode after DOMDocument::xinclude().

Fix #22624

Author: devnexen

ext/dom/node.c

@@ -245,11 +245,21 @@ zend_result dom_node_node_type_read(dom_object *obj, zval *retval)
 
 /* }}} */
 
+static xmlNodePtr dom_node_get_parent(dom_object *obj, xmlNodePtr nodep)
+{
+	if (nodep->type == XML_NAMESPACE_DECL) {
+		dom_object_namespace_node *ns = php_dom_namespace_node_obj_from_obj(&obj->std);
+		return ns->parent_intern ? dom_object_get_node(ns->parent_intern) : NULL;
+	}
+	return nodep->parent;
+}
+
+
 static zend_result dom_node_parent_get(dom_object *obj, zval *retval, bool only_element)
 {
 	DOM_PROP_NODE(xmlNodePtr, nodep, obj);
 
-	xmlNodePtr nodeparent = nodep->parent;
+	xmlNodePtr nodeparent = dom_node_get_parent(obj, nodep);
 	if (!nodeparent || (only_element && nodeparent->type != XML_ELEMENT_NODE)) {
 		ZVAL_NULL(retval);
 		return SUCCESS;
@@ -457,7 +467,12 @@ URL: https://dom.spec.whatwg.org/#dom-node-isconnected
 zend_result dom_node_is_connected_read(dom_object *obj, zval *retval)
 {
 	DOM_PROP_NODE(xmlNodePtr, nodep, obj);
-	ZVAL_BOOL(retval, php_dom_is_node_connected(nodep));
+	if (nodep->type == XML_NAMESPACE_DECL) {
+		xmlNodePtr parent = dom_node_get_parent(obj, nodep);
+		ZVAL_BOOL(retval, parent && php_dom_is_node_connected(parent));
+	} else {
+		ZVAL_BOOL(retval, php_dom_is_node_connected(nodep));
+	}
 	return SUCCESS;
 }
 /* }}} */

ext/dom/tests/gh22624.phpt

@@ -0,0 +1,41 @@
+--TEST--
+GH-22624 (Use-after-free via DOMNameSpaceNode after DOMDocument::xinclude())
+--CREDITS--
+ExPatch-LLC
+--EXTENSIONS--
+dom
+--SKIPIF--
+<?php
+if (!function_exists('libxml_set_external_entity_loader')) die('skip xinclude not available');
+?>
+--FILE--
+<?php
+$included = __DIR__ . '/gh22624_included.xml';
+file_put_contents($included, '<?xml version="1.0"?><included/>');
+$href = 'file:///' . ltrim(str_replace('\\', '/', $included), '/');
+
+$doc = new DOMDocument();
+$doc->loadXML('<?xml version="1.0"?>
+<root xmlns:xi="http://www.w3.org/2001/XInclude">
+  <xi:include href="' . $href . '" xmlns:local="urn:test"/>
+</root>');
+
+$xpath = new DOMXPath($doc);
+$xpath->registerNamespace('xi', 'http://www.w3.org/2001/XInclude');
+$xi = $xpath->query('//xi:include')->item(0);
+$ns = $xpath->query('namespace::local', $xi)->item(0); // DOMNameSpaceNode
+
+$doc->xinclude(); // frees the xi:include element
+
+var_dump($ns->parentNode);
+var_dump($ns->parentElement);
+var_dump($ns->isConnected);
+?>
+--CLEAN--
+<?php
+@unlink(__DIR__ . '/gh22624_included.xml');
+?>
+--EXPECT--
+NULL
+NULL
+bool(false)