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Fix use-after-free in property coercion with __toString() #14971

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Fix use-after-free in property coercion with __toString() #14971

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47 changes: 47 additions & 0 deletions Zend/tests/gh14969.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,47 @@
--TEST--
GH-14969: Crash on coercion with throwing __toString()
--FILE--
<?php

class C {
public function __toString() {
global $c;
$c = [];
throw new Exception(__METHOD__);
}
}

class D {
public string $prop;
}

$c = new C();
$d = new D();
try {
$d->prop = $c;
} catch (Throwable $e) {
echo $e->getMessage(), "\n";
}
var_dump($d);

$c = new C();
$d->prop = 'foo';
try {
$d->prop = $c;
} catch (Throwable $e) {
echo $e->getMessage(), "\n";
}
var_dump($d);

?>
--EXPECTF--
C::__toString
object(D)#%d (0) {
["prop"]=>
uninitialized(string)
}
C::__toString
object(D)#2 (1) {
["prop"]=>
string(3) "foo"
}
4 changes: 2 additions & 2 deletions Zend/zend_object_handlers.c
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Original file line number Diff line number Diff line change
Expand Up @@ -819,7 +819,7 @@ ZEND_API zval *zend_std_write_property(zend_object *zobj, zend_string *name, zva

ZVAL_COPY_VALUE(&tmp, value);
if (UNEXPECTED(!zend_verify_property_type(prop_info, &tmp, property_uses_strict_types()))) {
Z_TRY_DELREF_P(value);
zval_ptr_dtor(&tmp);
variable_ptr = &EG(error_zval);
goto exit;
}
Expand Down Expand Up @@ -890,7 +890,7 @@ ZEND_API zval *zend_std_write_property(zend_object *zobj, zend_string *name, zva

ZVAL_COPY_VALUE(&tmp, value);
if (UNEXPECTED(!zend_verify_property_type(prop_info, &tmp, property_uses_strict_types()))) {
zval_ptr_dtor(value);
zval_ptr_dtor(&tmp);
goto exit;
}
value = &tmp;
Expand Down