My login form returns invalid username/password even if it is correct

Question

I'm creating a simple user registration and login system. The registration works fine and it stores the users in DB. But when i try to login even if i get the username/password correct it still returns that It's not correct. I can't seem to find the problem here is the code. Login form:

<form method="post" action = 'plogin.php'>
            <h2 class="sr-only">Login Form</h2>
            <div class="illustration"><i class="icon ion-ios-navigate"></i></div>
            <div class="form-group"><input class="form-control" type="email" name="email" placeholder="Е-маил"></div>
            <div class="form-group"><input class="form-control" type="password" name="password" placeholder="Лозинка"></div>
            <div class="form-group"><button class="btn btn-primary btn-block" type="submit">Најава</button></div><a href="#" class="forgot">Ја заборавивте лозинката? Кликнете овде.</a></form>

Validation and checking if username and password exists:

<?php
session_start();

if(!empty($_POST)) {
    include('includes/general.php');
    if(!$connection){
        die("Failed to connect to database ".mysqli_connect_error());
    }
    $email = mysqli_real_escape_string($connection, $_POST['email']);
    $password = mysqli_real_escape_string($connection, $_POST['password']);
    $hashedPassword = hash('SHA256', $password);
    $query = "SELECT * FROM users WHERE email = '$email' AND password = '$password'";
    $result = mysqli_query($connection, $query) or die (mysqli_error($connection));
    if(mysqli_num_rows($result) > 0) {
        $_SESSION = mysqli_fetch_array($result);
        echo "<script>window.location.href = 'user.php';</script>";
    } else {
        echo "<script>alert('invalid username/password');
            window.location.href= 'login.php';</script>";

    }
} else {
    echo "<script>window.location.href = 'index.php';</script>";
}

Answer 1

You've mixed your variables. I guess your password is stored as hash, but you're comparing it to the unhashed value.

try instead

$password = mysqli_real_escape_string($connection, $_POST['password']);
$hashedPassword = hash('SHA256', $password);
$query = "SELECT * FROM users WHERE email = '$email' AND password = '$hashedPassword'";

Even though I wonder why you try to put the full result into $_SESSION. I wouldn't do that, if you need to have some values in your session (eg userId, email and username or similiar) I would just store those instead of all columns from the row. Also doing a query without specification of columns you want to retrieve is not best practice, see this topic for explaination.

You maybe want to check PHP-reference for password_hash and password_verify to improve your concept.

Answer 2

did you mean

$query = "SELECT * FROM users WHERE email = '$email' AND password = '$hashedDassword'"; 

?

and also, I Highly advise AGAINST writing your own registration and sign up form, unless this is for an exercise.

Answer 3

嘿，不要对 PHP 变量使用单引号，请使用 string con cat (.) 运算符

$query = "SELECT * FROM users WHERE email = '".$email."' AND password = '".$password."'";