黑名單過濾，同時(shí)不能進(jìn)行雙寫，大小寫，特殊可解析后綴，.htaccess,都不能。點(diǎn)擊提示發(fā)現(xiàn)：

禁止上傳所有可解析后綴，抓包試試：

抓包加空格發(fā)現(xiàn)也不能繞過，看源碼分析吧：

$is_upload = false;
$msg = null;
if (isset($_POST['submit'])) {if (file_exists(UPLOAD_PATH)) {$deny_ext = array(".php",".php5",".php4",".php3",".php2",".html",".htm",".phtml",".pht",".pHp",".pHp5",".pHp4",".pHp3",".pHp2",".Html",".Htm",".pHtml",".jsp",".jspa",".jspx",".jsw",".jsv",".jspf",".jtml",".jSp",".jSpx",".jSpa",".jSw",".jSv",".jSpf",".jHtml",".asp",".aspx",".asa",".asax",".ascx",".ashx",".asmx",".cer",".aSp",".aSpx",".aSa",".aSax",".aScx",".aShx",".aSmx",".cEr",".sWf",".swf",".htaccess",".ini");$file_name = trim($_FILES['upload_file']['name']);$file_ext = strrchr($file_name, '.');$file_ext = strtolower($file_ext); //轉(zhuǎn)換為小寫$file_ext = str_ireplace('::$DATA', '', $file_ext);//去除字符串::$DATA$file_ext = trim($file_ext); //首尾去空if (!in_array($file_ext, $deny_ext)) {$temp_file = $_FILES['upload_file']['tmp_name'];$img_path = UPLOAD_PATH.'/'.$file_name;if (move_uploaded_file($temp_file, $img_path)) {$is_upload = true;} else {$msg = '上傳出錯(cuò)！';}} else {$msg = '此文件類型不允許上傳！';}} else {$msg = UPLOAD_PATH . '文件夾不存在,請(qǐng)手工創(chuàng)建！';}
}

?可以看到，相比前一關(guān)，這里多了一個(gè)前后空格的去除，因此這里用加點(diǎn)繞過：

1. $file_ext = strrchr($file_name, '.'); 這行代碼使用strrchr函數(shù)獲取文件名中的最后一個(gè)點(diǎn)（.）之后的部分，即文件擴(kuò)展名。而不會(huì)去除我們加的.。但是在Windows下，這個(gè)點(diǎn)和空格一樣，都會(huì)被忽略。

上傳成功，試試：