Fuzzer `php-fuzz-execute` crashes at `zend_lazy_object_init`

Description

The following code:

<?php
class Test {
    public function __isset($x) { $GLOBALS["obj"] = 24; return true; }
    public function a($x) { }
}
$obj = new Test;
var_dump($obj->$name ?? 12);
?>

Resulted in this crashing call stack by the fuzzing driver php-fuzz-execute:

#6  __GI___assert_fail (assertion=0xdec74d "info", file=0xe24f2e "/src/php-src/Zend/zend_lazy_objects.c", line=110, function=0xe2576a "zend_lazy_object_info *zend_lazy_object_get_info(zend_object *)") at ./assert/assert.c:103
#7  zend_lazy_object_init () at Zend/zend_lazy_objects.c:513
#8  zend_std_read_property () at Zend/zend_object_handlers.c:954
#9   ZEND_FETCH_OBJ_IS_SPEC_CV_CV_HANDLER () at Zend/zend_vm_execute.h:52811
#10 fuzzer_execute_ex () at sapi/fuzzer/fuzzer-execute-common.h:59
#11 zend_execute () at Zend/zend_vm_execute.h:64385
#12 fuzzer_do_request_from_buffer () at sapi/fuzzer/fuzzer-sapi.c:274
#13 LLVMFuzzerTestOneInput () at sapi/fuzzer/fuzzer-execute.c:27

PHP Version

dbabbe180b157eeaac5002276667f1f56f0b4def 2025-06-10 22:35:56+0200

Operating System

Linux

まず、提供されたスクリプトを php-fuzz-execute ドライバーで再現します。Zend/zend_lazy_objects.c の zend_lazy_object_init 周辺を読み、Zend/zend_object_handlers.c を通じてプロパティアクセスを追跡し、その後 sapi/fuzzer/fuzzer-execute-common.h と sapi/fuzzer/fuzzer-sapi.c の fuzzer エントリーポイントを確認します。reproducer が assertion を引き起こさなくなり、適切なテスト場所が特定された場合に回帰テストのカバレッジが追加されていれば完了です。