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Fix GH-19098: libxml<2.13 segmentation fault caused by php_libxml_node_free #19186

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Fix GH-19098: libxml<2.13 segmentation fault caused by php_libxml_node_free #19186

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27 changes: 20 additions & 7 deletions ext/libxml/libxml.c
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Original file line number Diff line number Diff line change
Expand Up @@ -331,13 +331,26 @@ PHP_LIBXML_API void php_libxml_node_free_list(xmlNodePtr node)
if (curnode->type == XML_ELEMENT_NODE) {
/* This ensures that namespace references in this subtree are defined within this subtree,
* otherwise a use-after-free would be possible when the original namespace holder gets freed. */
#if 0
xmlDOMWrapCtxt dummy_ctxt = {0};
xmlDOMWrapReconcileNamespaces(&dummy_ctxt, curnode, /* options */ 0);
#else
/* See php_dom.c */
xmlReconciliateNs(curnode->doc, curnode);
#endif
if (LIBXML_VERSION < 21300 && UNEXPECTED(curnode->doc == NULL)) {
/* xmlReconciliateNs() in these versions just uses the document for xmlNewReconciledNs(),
* which can create an oldNs xml namespace declaration via xmlSearchNs() -> xmlTreeEnsureXMLDecl(). */
xmlDoc dummy;
memset(&dummy, 0, sizeof(dummy));
dummy.type = XML_DOCUMENT_NODE;
curnode->doc = &dummy;
xmlReconciliateNs(curnode->doc, curnode);
curnode->doc = NULL;

/* Append oldNs to current node's nsDef, which can be at most one node. */
if (dummy.oldNs) {
ZEND_ASSERT(dummy.oldNs->next == NULL);
xmlNsPtr old = curnode->nsDef;
curnode->nsDef = dummy.oldNs;
dummy.oldNs->next = old;
}
} else {
xmlReconciliateNs(curnode->doc, curnode);
}
}
/* Skip freeing */
curnode = next;
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44 changes: 44 additions & 0 deletions ext/xmlreader/tests/gh19098.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,44 @@
--TEST--
GH-19098 (libxml<2.13 segmentation fault caused by php_libxml_node_free)
--EXTENSIONS--
xmlreader
dom
--FILE--
<?php

$xml_reader = \XMLReader::XML('
<sparql xmlns="http://www.w3.org/2005/sparql-results#">
<results>
<result><binding xml:id="foo" xmlns:custom="urn:custom" custom:foo="bar" name="s"><uri/></binding></result>
</results>
</sparql>');

$success = $xml_reader->next("sparql");

$success = $xml_reader->read();
$success = $xml_reader->next("results");

while ($xml_reader->read()) {
if ($xml_reader->next("result")) {
$result_as_dom_node = $xml_reader->expand();
$child = $result_as_dom_node->firstChild;
unset($result_as_dom_node);
var_dump($child->namespaceURI);
foreach ($child->attributes as $attr) {
var_dump($attr->namespaceURI);
}
$doc = new DOMDocument;
$doc->adoptNode($child);
echo $doc->saveXML($child), "\n";
unset($child);
break;
}
}

?>
--EXPECT--
string(38) "http://www.w3.org/2005/sparql-results#"
string(36) "http://www.w3.org/XML/1998/namespace"
string(10) "urn:custom"
NULL
<default:binding xmlns:custom="urn:custom" xmlns:default="http://www.w3.org/2005/sparql-results#" xml:id="foo" custom:foo="bar" name="s"><default:uri/></default:binding>
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