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Fix UAF when setAttributeNS() frees a wrapped attribute child #23348

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Fix UAF when setAttributeNS() frees a wrapped attribute child #23348

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2 changes: 2 additions & 0 deletions NEWS
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,8 @@ PHP NEWS
- DOM:
. Fixed a use-after-free when cloning a DOMNameSpaceNode after
DOMDocument::xinclude(). (iliaal)
. Fixed a use-after-free when Dom\Element::setAttributeNS() replaces the
value of an attribute whose child still has a live wrapper. (iliaal)

- Intl:
. Fixed a double-free when IntlGregorianCalendar construction fails after
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4 changes: 4 additions & 0 deletions ext/dom/element.c
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Expand Up @@ -1030,6 +1030,10 @@ static void dom_set_attribute_ns_modern(dom_object *intern, xmlNodePtr elemp, ze
if (errorcode == 0) {
php_dom_libxml_ns_mapper *ns_mapper = php_dom_get_ns_mapper(intern);
xmlNsPtr ns = php_dom_libxml_ns_mapper_get_ns_raw_prefix_string(ns_mapper, prefix, xmlStrlen(prefix), uri);
xmlNodePtr existing = (xmlNodePtr) xmlHasNsProp(elemp, localname, ns == NULL ? NULL : ns->href);
if (existing != NULL && existing->type != XML_ATTRIBUTE_DECL) {
node_list_unlink(existing->children);
}
xmlAttrPtr attr = xmlSetNsProp(elemp, ns, localname, BAD_CAST value);
if (UNEXPECTED(attr == NULL)) {
php_dom_throw_error(INVALID_STATE_ERR, /* strict */ true);
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37 changes: 37 additions & 0 deletions ext/dom/tests/modern/common/Element_setAttributeNS_live_child.phpt
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@@ -0,0 +1,37 @@
--TEST--
setAttributeNS() keeps an attribute child that still has a live wrapper
--EXTENSIONS--
dom
--FILE--
<?php

$doc = Dom\XMLDocument::createFromString('<root xmlns:p="urn:x" p:attr="old"/>');
$el = $doc->documentElement;
$text = $el->getAttributeNodeNS('urn:x', 'attr')->firstChild;
$el->setAttributeNS('urn:x', 'p:attr', 'new');
echo "prefixed, detached: ";
var_dump($text->parentNode === null);
echo "prefixed, text: ";
var_dump($text->textContent);
echo "prefixed, new value: ";
var_dump($el->getAttributeNS('urn:x', 'attr'));

$doc = Dom\XMLDocument::createFromString('<root attr="old"/>');
$el = $doc->documentElement;
$text = $el->getAttributeNode('attr')->firstChild;
$el->setAttributeNS(null, 'attr', 'new');
echo "no namespace, detached: ";
var_dump($text->parentNode === null);
echo "no namespace, text: ";
var_dump($text->textContent);
echo "no namespace, new value: ";
var_dump($el->getAttribute('attr'));

?>
--EXPECT--
prefixed, detached: bool(true)
prefixed, text: string(3) "old"
prefixed, new value: string(3) "new"
no namespace, detached: bool(true)
no namespace, text: string(3) "old"
no namespace, new value: string(3) "new"
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