php和mysql登录脚本错误

Question

I've made a php login script and it just not works.

my code :

<?php

function clean($str) { /* sanatize strings for databases & security */
  $str = trim($str);
    if(get_magic_quotes_gpc()) {
        $str = stripslashes($str);
    }
    return mysql_real_escape_string($str);
}

if (!empty($_POST['login_admin'])) {

    $username = clean($_POST['name']);
    $password = clean($_POST['password']);

      try {
        $dbh = new PDO('mysql:host=localhost;dbname=imedia', "imedia", "imedia");

        $statement = $dbh->prepare("SELECT * FROM administratori WHERE username =:username AND parola =:password");
        $statement->execute(array(":username" => $username, ":password" => md5($password)));
        $row = $statement->fetch();
        if ($row) {
            session_start("imedia_admin");
            $_SESSION['imedia_admin']['logname'] = $row['username'];
            $_SESSION['imedia_admin']['password'] = $row['password'];
            echo json_encode("success");
        } else {
            echo json_encode("error");
        }

        $dbh = null;
    } catch (PDOException $e) {
        print "Error!: " . $e->getMessage() . "<br/>";
        die();
    }
}
?>

problem is in clean function, if a do not use it, my code works, can anybody explain me what i am doing wrong please ?

Answer 1

PDO will take care of it (it automatically escapes single quotes or sanitizes it for you). don't pass the variable with your own clean function.

Here's what's going on.

• let's say you have this string hello world's day
• passing to you function clean makes it hello world''s day
• then on PDO it escapes it again making it hello world''''s day
• causing (mismatched) hello world's day not equal to hello world''s day