Question

I have a very simple login/user registration script that stores passwords using sha1 and salt. I have the passwords and user creation working fine and storing everything in the database just fine, but when I try to log in with the credentials, it doesn’t work. I can’t seem to find anything upon searching this topic.

Here is my add user form:

session_start();
include("includes/resume.config.php");

// make sure form fields have a value and strip them
function check_input($data, $problem='')
{
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
if ($problem && strlen($data) == 0)
{
    die($problem);
}
    return $data;
}

// get form values, escape them and apply the check_input function
$name = $link->real_escape_string(check_input($_POST['name'], "Please enter a name!"));
$email = $link->real_escape_string(check_input($_POST['email'], "Please enter an email!"));
$password = $link->real_escape_string(check_input($_POST['password'], "Please enter a password!"));

// generate a random salt for converting passwords into MD5
$salt = bin2hex(mcrypt_create_iv(32, MCRYPT_DEV_URANDOM));
$saltedPW =  $password . $salt;
$hashedPW = sha1($saltedPW);

mysqli_connect($db_host, $db_user, $db_pass) OR DIE (mysqli_error());
// select the db
mysqli_select_db ($link, $db_name) OR DIE ("Unable to select db".mysqli_error($db_name));

 // our sql query
$sql = "INSERT INTO admins (name, email, password, salt) VALUES ('$name', '$email', '$hashedPW', '$salt');";

//save the updated information to the database          
mysqli_query($link, $sql) or die("Error in Query: " . mysqli_error($link));

if (!mysqli_error($link)) 
{
    header("Location: file_insert.php");
}   

And here is my login script: This is what is not working

function check_input($data, $problem='')
{
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
if ($problem && strlen($data) == 0)
{
    die($problem);
}
    return $data;
}

if(isset($_POST['submitLogin'])) { //form submitted?

// get form values, escape them and apply the check_input function
$name = $link->real_escape_string(check_input($_POST['name'], "Please enter a name!"));
$password = $link->real_escape_string(check_input($_POST['password'], "Please enter a password!"));

$saltQuery = $link->query('SELECT salt FROM admins WHERE name = "'.$name.'"');

$salt = mysqli_fetch_assoc($saltQuery);
$saltedPW =  $password . $salt;
$hashedPW = sha1($saltedPW);

mysqli_connect($db_host, $db_user, $db_pass) OR DIE (mysqli_error());
// select the db
mysqli_select_db ($link, $db_name) OR DIE ("Unable to select db".mysqli_error($db_name));

$validate_user = $link->query('SELECT id, name, password FROM admins WHERE name = "'.$name.'" AND password = "'.$hashedPW.'"');

if ($validate_user->num_rows == 1) {
    $row = $validate_user->fetch_assoc();
    $_SESSION['id'] = $row['id'];
    $_SESSION['loggedin'] = TRUE;
    Header('Location: file_insert.php');
} else {
    print "<center><p style='margin-top: 200px; font-weight: bold;'>Invalid Login Information</p>";
    print "<a href='admin-login.php'>Click here</a> to return to the login page.</center>";
}
}

Answer 1

There may be more going on, but certainly one reason it isn’t working is because mysqli_fetch_assoc returns an array, and you are using it like a string.

PHP would complain about an array to string conversion when you call $password . $salt since at this point $salt is an array. The result is that you get the word Array appended to the password which results in an incorrect hash. If you have display_errors off and/or error_reporting set to hide notices in php.ini then you wont see this message.

If you change:

$saltedPW =  $password . $salt;

to:

$saltedPW =  $password . $salt['salt'];

then it should work.

In addition, you should escape $salt before you insert it into the database because its possible it could contain null, unprintable, or single/double quotes since its randomly generated.