<?php

class LinuxAuth {
    /** @author Marcus Brasizza
     *
     * @version 1.0.0
     */
    private $pathShadow = '/etc/shadow';
    private $pathPasswd = '/etc/passwd';
    private $authConfig = '/etc/sysconfig/authconfig';
    private $authConfigTMP = '/tmp/authconfig';
    private $content = null;
    private $useType = null;


    /**
     *  Constructor
     */
    function __construct() {
        exec('sudo cp  ' . $this->authConfig . ' /tmp/');
        exec('chmod 777 -R  ' . $this->authConfigTMP);
        $authCon = file_get_contents($this->authConfigTMP);
        $strFind = 'USESHADOW';
        $tamFind = strlen($strFind);
        $posShadow = strpos($authCon, $strFind);
        if ($posShadow !== false) {
            $useFind = trim(substr($authCon, ($posShadow + $tamFind + 1), 3));

            if ($useFind == 'yes') {
                $this->useType = 'shadow';
                exec('sudo cp /etc/shadow  /tmp/');
                exec('sudo chmod 777 -R /tmp/shadow');
                $file = file('/tmp/shadow');
                $this->content = $file;
                unlink('/tmp/shadow');
            } else {
                $this->useType = 'passwd';
                exec('sudo cp /etc/passwd  /tmp/');
                exec('sudo chmod 777 -R /tmp/passwd');
                $file = file('/tmp/passwd');
                $this->content = $file;
                unlink('/tmp/passwd');
            }
        }
    }



    final private function getUserInfo($username) {
        if (isset($this->content)) {
            foreach ($this->content as $line) {
                $data = explode(':', $line);
                $user = trim($data[0]);
                if ($user == $username) {
                    $pass = trim($data[1]);
                    $info = new stdClass();
                    $info->username = $user;
                    $info->password = $pass;
                    return $info;
                }
            }
        }
        return false;
    }

    /**
     * Username Access
     * @param Username $username
     * @param Password $password
     * @return boolean true if the user is in the password file system
     * @access public
     * @uses $myauth->authUser('myUsername','mypasswordBased64');
     */
    public function authUser($username,$password){
        $myInfo = $this->getUserInfo($username);
        if($myInfo != false){
            $password = base64_decode($password);
            $passHashed = crypt($password, $myInfo->password);
            return trim($passHashed) ===  trim($myInfo->password);
        }
        return false;

    }

}
?>





<?php

//Como utilizar

$lin = new LinuxAuth();
$myPass = base64_encode('myPassword');
$myUser = 'root';
if($lin->authUser($myUser,$myPass)){
    echo " AUTENTICADO";
}else{
    echo " NAO AUTENTICADO";
}

?>