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ext/xml: reject changing handlers while parsing #23818

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Merged
Girgias merged 1 commit into from
Sep 21, 2026
+54 −0
Merged

ext/xml: reject changing handlers while parsing #23818

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43 changes: 43 additions & 0 deletions ext/xml/tests/xml_set_handler_reentrancy.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,43 @@
--TEST--
GH-23818 (Changing XML handlers while parsing is rejected)
--EXTENSIONS--
xml
--FILE--
<?php

$startHandler = static function (XMLParser $parser): void {
$replacement = static function () {};

try {
xml_set_element_handler($parser, $replacement, $replacement);
} catch (Error $error) {
echo 'xml_set_element_handler: ', $error->getMessage(), "\n";
}

try {
xml_set_character_data_handler($parser, $replacement);
} catch (Error $error) {
echo 'xml_set_character_data_handler: ', $error->getMessage(), "\n";
}
};

$parser = xml_parser_create();
xml_set_element_handler($parser, $startHandler, static function () {
echo "end\n";
});
xml_set_character_data_handler($parser, static function (XMLParser $parser, string $data) {
echo $data, "\n";
});

var_dump(xml_parse($parser, '<root>text</root>', true));
var_dump(xml_set_element_handler($parser, null, null));
var_dump(xml_set_character_data_handler($parser, null));
?>
--EXPECT--
xml_set_element_handler: Cannot change handlers while parsing
xml_set_character_data_handler: Cannot change handlers while parsing
text
end
int(1)
bool(true)
bool(true)
11 changes: 11 additions & 0 deletions ext/xml/xml.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1308,6 +1308,12 @@ PHP_FUNCTION(xml_set_element_handler)
}

set_handlers:
if (parser->isparsing) {
zend_release_fcall_info_cache(&start_fcc);
zend_release_fcall_info_cache(&end_fcc);
zend_throw_error(NULL, "Cannot change handlers while parsing");
RETURN_THROWS();
}
xml_set_handler(&parser->startElementHandler, &start_fcc);
xml_set_handler(&parser->endElementHandler, &end_fcc);
XML_SetElementHandler(parser->parser, xml_startElementHandler, xml_endElementHandler);
Expand Down Expand Up @@ -1361,6 +1367,11 @@ static void php_xml_set_handler_parse_callable(
php_xml_set_handler_parse_callable(INTERNAL_FUNCTION_PARAM_PASSTHRU, &parser, &handler_fcc); \
if (EG(exception)) { return; } \
ZEND_ASSERT(parser); \
if (parser->isparsing) { \
zend_release_fcall_info_cache(&handler_fcc); \
zend_throw_error(NULL, "Cannot change handlers while parsing"); \
RETURN_THROWS(); \
} \
xml_set_handler(&parser->parser_handler_name, &handler_fcc); \
parse_function(parser->parser, c_function); \
RETURN_TRUE; \
Expand Down
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