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Fix various document ref pointer mismanagements #16345

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Fix various document ref pointer mismanagements #16345

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5 changes: 2 additions & 3 deletions ext/dom/element.c
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Original file line number Diff line number Diff line change
Expand Up @@ -642,9 +642,8 @@ PHP_METHOD(DOMElement, setAttributeNode)
xmlUnlinkNode((xmlNodePtr) attrp);
}

if (attrp->doc == NULL && nodep->doc != NULL) {
attrobj->document = intern->document;
php_libxml_increment_doc_ref((php_libxml_node_object *)attrobj, NULL);
if (attrp->doc == NULL && nodep->doc != NULL && intern->document != NULL) {
dom_set_document_ref_pointers_attr(attrp, intern->document);
}

xmlAddChild(nodep, (xmlNodePtr) attrp);
Expand Down
53 changes: 42 additions & 11 deletions ext/dom/node.c
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Expand Up @@ -820,25 +820,56 @@ int dom_node_text_content_write(dom_object *obj, zval *newval)

/* }}} */

/* Returns true if the node was changed, false otherwise. */
static bool dom_set_document_ref_obj_single(xmlNodePtr node, xmlDocPtr doc, php_libxml_ref_obj *document)
/* Returns true if the node had the same document reference, false otherwise. */
static bool dom_set_document_ref_obj_single(xmlNodePtr node, php_libxml_ref_obj *document)
{
dom_object *childobj = php_dom_object_get_data(node);
if (childobj && !childobj->document) {
if (!childobj) {
return true;
}
if (!childobj->document) {
childobj->document = document;
document->refcount++;
return true;
}
return false;
}

void dom_set_document_ref_pointers_attr(xmlAttrPtr attr, php_libxml_ref_obj *document)
{
ZEND_ASSERT(document != NULL);

dom_set_document_ref_obj_single((xmlNodePtr) attr, document);
for (xmlNodePtr attr_child = attr->children; attr_child; attr_child = attr_child->next) {
dom_set_document_ref_obj_single(attr_child, document);
}
}

static bool dom_set_document_ref_pointers_node(xmlNodePtr node, php_libxml_ref_obj *document)
{
ZEND_ASSERT(document != NULL);

if (!dom_set_document_ref_obj_single(node, document)) {
return false;
}

if (node->type == XML_ELEMENT_NODE) {
for (xmlAttrPtr attr = node->properties; attr; attr = attr->next) {
dom_set_document_ref_pointers_attr(attr, document);
}
}

return true;
}

/* TODO: on 8.4 replace the loop with the tree walk helper function. */
static void dom_set_document_pointers(xmlNodePtr node, xmlDocPtr doc, php_libxml_ref_obj *document)
void dom_set_document_ref_pointers(xmlNodePtr node, php_libxml_ref_obj *document)
{
/* Applies the document to the entire subtree. */
xmlSetTreeDoc(node, doc);
if (!document) {
return;
}

if (!dom_set_document_ref_obj_single(node, doc, document)) {
if (!dom_set_document_ref_pointers_node(node, document)) {
return;
}

Expand All @@ -847,7 +878,7 @@ static void dom_set_document_pointers(xmlNodePtr node, xmlDocPtr doc, php_libxml
while (node != NULL) {
ZEND_ASSERT(node != base);

if (!dom_set_document_ref_obj_single(node, doc, document)) {
if (!dom_set_document_ref_pointers_node(node, document)) {
break;
}

Expand Down Expand Up @@ -974,7 +1005,7 @@ PHP_METHOD(DOMNode, insertBefore)
}

if (child->doc == NULL && parentp->doc != NULL) {
dom_set_document_pointers(child, parentp->doc, intern->document);
dom_set_document_ref_pointers(child, intern->document);
}

php_libxml_invalidate_node_list_cache(intern->document);
Expand Down Expand Up @@ -1149,7 +1180,7 @@ PHP_METHOD(DOMNode, replaceChild)
}

if (newchild->doc == NULL && nodep->doc != NULL) {
dom_set_document_pointers(newchild, nodep->doc, intern->document);
dom_set_document_ref_pointers(newchild, intern->document);
}

if (newchild->type == XML_DOCUMENT_FRAG_NODE) {
Expand Down Expand Up @@ -1252,7 +1283,7 @@ PHP_METHOD(DOMNode, appendChild)
}

if (child->doc == NULL && nodep->doc != NULL) {
dom_set_document_pointers(child, nodep->doc, intern->document);
dom_set_document_ref_pointers(child, intern->document);
}

if (child->parent != NULL){
Expand Down
2 changes: 2 additions & 0 deletions ext/dom/php_dom.h
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Original file line number Diff line number Diff line change
Expand Up @@ -154,6 +154,8 @@ bool php_dom_is_node_connected(const xmlNode *node);
bool php_dom_adopt_node(xmlNodePtr nodep, dom_object *dom_object_new_document, xmlDocPtr new_document);
xmlNsPtr dom_get_ns_resolve_prefix_conflict(xmlNodePtr tree, const char *uri);
xmlEntityPtr dom_entity_reference_fetch_and_sync_declaration(xmlNodePtr reference);
void dom_set_document_ref_pointers(xmlNodePtr node, php_libxml_ref_obj *document);
void dom_set_document_ref_pointers_attr(xmlAttrPtr attr, php_libxml_ref_obj *document);

/* parentnode */
void dom_parent_node_prepend(dom_object *context, zval *nodes, uint32_t nodesc);
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18 changes: 18 additions & 0 deletions ext/dom/tests/gh16336_1.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,18 @@
--TEST--
GH-16336 (Attribute intern document mismanagement)
--EXTENSIONS--
dom
--FILE--
<?php

$doc = new DOMDocument();
$elem = new DOMElement("g");
$attr = new DOMAttr("iF", "j");

$doc->appendChild($elem);
$elem->setAttributeNode($attr);
echo $attr->firstChild->textContent;

?>
--EXPECT--
j
18 changes: 18 additions & 0 deletions ext/dom/tests/gh16336_2.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,18 @@
--TEST--
GH-16336 (Attribute intern document mismanagement)
--EXTENSIONS--
dom
--FILE--
<?php

$doc = new DOMDocument();
$elem = new DOMElement("g");
$attr = new DOMAttr("iF", "j");

$elem->setAttributeNode($attr);
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it took consulting an external tool (https://www.diffchecker.com/) to figure out that the difference between the _1 and _2 tests was the order of these two statements - suggest adding a comment to make it clearer to the next person that passes along

$doc->appendChild($elem);
echo $attr->firstChild->textContent;

?>
--EXPECT--
j
27 changes: 27 additions & 0 deletions ext/dom/tests/gh16338.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,27 @@
--TEST--
GH-16338 (Null-dereference in ext/dom/node.c)
--EXTENSIONS--
dom
--CREDITS--
chibinz
--FILE--
<?php
$ref = new DOMEntityReference("G");
$com = new DOMComment();
$doc = new DOMDocument();
$elem = new DOMElement("Rj", "o");
$com2 = new DOMComment();
$elem2 = new DOMElement("kx", null, "r");

$elem2->prepend($com);
$com->before("Z");
$com->before($com2);
$com2->after($elem);
$doc->insertBefore($elem2);
$elem->insertBefore($ref);

echo $doc->saveXML();
?>
--EXPECT--
<?xml version="1.0"?>
<kx xmlns="r">Z<Rj>o&G;</Rj></kx>
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