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ext/dom: Use-after-free with namespace nodes from XSLTProcessor::regi… #22623

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6 changes: 3 additions & 3 deletions ext/dom/xpath_callbacks.c
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Original file line number Diff line number Diff line change
Expand Up @@ -347,15 +347,15 @@ static zval *php_dom_xpath_callback_fetch_args(xmlXPathParserContextPtr ctxt, ui
xmlNodePtr node = obj->nodesetval->nodeTab[j];
zval child;
if (UNEXPECTED(node->type == XML_NAMESPACE_DECL)) {
xmlNodePtr nsparent = node->_private;
xmlNsPtr original = (xmlNsPtr) node;

/* Make sure parent dom object exists, so we can take an extra reference. */
zval parent_zval; /* don't destroy me, my lifetime is transferred to the fake namespace decl */
php_dom_create_object(nsparent, &parent_zval, intern);
proxy_factory(node->_private, &parent_zval, intern, ctxt);
dom_object *parent_intern = Z_DOMOBJ_P(&parent_zval);
xmlNodePtr parent = dom_object_get_node(parent_intern);

php_dom_create_fake_namespace_decl(nsparent, original, &child, parent_intern);
php_dom_create_fake_namespace_decl(parent, original, &child, parent_intern);
} else {
proxy_factory(node, &child, intern, ctxt);
}
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63 changes: 63 additions & 0 deletions ext/xsl/tests/gh22621.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,63 @@
--TEST--
GH-22621 (UAF via XSLTProcessor::registerPHPFunctions() retaining namespace nodes from an external document)
--EXTENSIONS--
dom
xsl
--CREDITS--
ExPatch-LLC
--FILE--
<?php
$cDIR = __DIR__;
file_put_contents($cDIR . '/gh22621_external.xml', '<root xmlns:custom="urn:custom"><data>secret</data></root>');
$uri = 'file:///' . ltrim(str_replace('\\', '/', $cDIR), '/') . '/gh22621_external.xml';

$stored_ns = null;

function capture_ns($nodes) {
global $stored_ns;
foreach ($nodes as $node) {
if ($node instanceof DOMNameSpaceNode) {
$stored_ns = $node;
}
}
return "captured";
}

$xsl = new DOMDocument();
$xsl->loadXML(<<<XSL
<?xml version="1.0"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:php="http://php.net/xsl">
<xsl:template match="/">
<result>
<xsl:value-of select="php:function('capture_ns', document('$uri')/*/namespace::*)"/>
</result>
</xsl:template>
</xsl:stylesheet>
XSL);

$doc = new DOMDocument();
$doc->loadXML('<input/>');

$proc = new XSLTProcessor();
$proc->registerPHPFunctions();
$proc->importStylesheet($xsl);
echo $proc->transformToXml($doc);

var_dump($stored_ns->localName);
var_dump($stored_ns->namespaceURI);
var_dump($stored_ns->parentNode->localName);
var_dump($stored_ns->ownerDocument instanceof DOMDocument);
?>
--CLEAN--
<?php
@unlink(__DIR__ . '/gh22621_external.xml');
?>
--EXPECTF--
<?xml version="1.0"?>
<result xmlns:php="http://php.net/xsl">captured</result>
string(6) "custom"
string(10) "urn:custom"
string(4) "root"
bool(true)
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