php realpath() returns 空字符串

Question

受此指导 post Preventing Directory Traversal in PHP but allowing paths 我试图阻止目录遍历，但我遇到了一些奇怪的事情，首先是 realpath returns 一个好的路径

        $fPath = $path.$parent.'/'.$name;
//$name (the user input) in this sample is "fff", $parent is an empty string        

        //make sure user didn't try to traverse backwards on the basepath           
        $basepath = $path;
        $realBase = realpath($basepath);
echo $realBase."<br/>";
//gives: /Users/me/Documents/www/gallery/php_sample/uploadedImages

        $userpath = $fPath;
echo $userpath."<br/>";
//gives: /Users/me/Documents/www/gallery/php_sample/uploadedImages/fff

        $realUserPath = realpath($userpath);
echo $realUserPath."<br/>";
//gives blank (an empty string).

有什么想法吗？

Answer 1

正如 AbraCadaver 在评论中所说，"This only works if the dir exists. To validate/sanitize the user supplied dir you will need some rules and clean it or reject it."

php realpath() returns 空字符串

php realpath() returns a blank string

php

filesystems

directory

traversal