PDO reads the database, but does not log into system - php

Question

I currently have a login system, which I would like to convert to PDO from Mysqli.
I currently have a website with a database attached with phpMyAdmin/MySQL.
I tried to convert everything and I will now show you the LOGIN.php part of the system since I haven't touched the signup part yet.
This is what I have.
LOGIN.INC.PHP
<?php
require_once 'dbh.inc.php';
try {
$handler = new PDO("mysql:host=$servername;dbname=$dbname",
$username,
$password,
array(PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION));
} catch(PDOException $e){
echo $e->getName();
die();
}
//first we start a session
session_start();
//We then check if the user has clicked the login button
if (isset($_POST['submit'])) {
//Then we require the database connection
//require_once 'dbh.inc.php';
//And we get the data from the login form
$name = $_POST['name'];
$password = $_POST['password'];
//Error handlers
//Error handlers are important to avoid any mistakes the user might have made when filling out the form!
//Check if inputs are empty
if (empty($name) || empty($password)) {
header("Location: ../index.php?login=empty");
exit();
}
} else {
$stmt = $db->prepare("SELECT * FROM users WHERE user_name=:name");
$stmt->bindParam(':name', $name, PDO::PARAM_STR);
if ($stmt->execute()) {
header("location: ../index.php?login=error");
exit();
} else {
if ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
//de-hashing the password
$hashedpasswordCheck = password_verify($password, $row['user_password']);
if ($hashedpasswordCheck == false) {
header("location: ../index.php?login=error");
exit();
} elseif ($hashedpasswordCheck == true) {
//Log in the user here
$_SESSION['u_id'] = $row['user_id'];
$_SESSION['u_name'] = $row['user_name'];
header("location: ../index.php?login=success");
exit();
}
} else {
header("location: ../index.php?login=error");
exit();
}
}
}
DBH.INC.PHP
<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "loginsystem";
try {
$conn = new PDO("mysql:host=$servername;dbname=$dbname",
$username,
$password,
array(PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION));
$stmt = $conn->prepare("SHOW DATABASES;");
$stmt->execute();
$stmt->setFetchMode(PDO::FETCH_ASSOC);
$result = $stmt->fetchAll();
print_r($result);
}
catch(PDOException $e) {
echo $e->getMessage();
}
$conn = null;
When I try to login I get redirected to this url:
http://localhost/php44/includes/login.inc.php
and receive this printed message/error.
Array ( [0] => Array ( [Database] => imgupload ) [1] => Array ( [Database] => information_schema ) [2] => Array ( [Database] => loginsystem ) [3] => Array ( [Database] => mysql ) [4] => Array ( [Database] => performance_schema ) [5] => Array ( [Database] => phpmyadmin ) [6] => Array ( [Database] => test ) )
What should I do to fix this, so that my login works?

Answer 1

Your code is vulnerable to Html Elements Injection and session fixation attack. I have implemented strip_tags() to prevents html element injection attack and have also implemented session_regenerate_id(); to prevent session fixation attack.
Again since you are login, you only need to initialize session as soon as username and password is verified.
As for me, I prefer using PDO array method. Anyway I have provided two solution. I first work on your code and then modify it were appropriate. Ensure that database credentials is okay
Your code
<?php
//db connect starts
$db = new PDO (
'mysql:host=localhost;dbname=loginsystem;charset=utf8',
'root', // username
'' // password
);
//We then check if the user has clicked the login button
if (isset($_POST['submit'])) {
$name = $_POST['name'];
$password = $_POST['password'];
if ($name =='' && $password =='') {
header("Location: ../index.php?login=empty");
exit();
}
$stmt = $db->prepare("SELECT * FROM users WHERE user_name=:name");
$stmt->bindParam(':name', $name, PDO::PARAM_STR);
$stmt->execute();
$count = $stmt->rowCount();
if( $count == 1 ) {
$row = $stmt->fetch();
if(password_verify($password,$row['password'])){
echo "Password verified and ok";
// initialize session if things where ok.
session_start();
//Prevent session fixation attack
session_regenerate_id();
$_SESSION['u_id'] = $row['user_id'];
$_SESSION['u_name'] = $row['user_name'];
header("location: ../index.php?login=success");
exit();
}
else{
echo "Wrong Password details";
}
}
else {
echo "User does not exist";
}
}
?>
my code
<?php
//if (isset($_POST['submit'])) {
if ($_POST['name'] !='' && $_POST['password']) {
//connect
$db = new PDO (
'mysql:host=localhost;dbname=loginsystem;charset=utf8',
'root', // username
'' // password
);
$name = strip_tags($_POST['name']);
$password = strip_tags($_POST['password']);
if ($name == ''){
echo "Username is empty";
exit();
}
if ($password == ''){
echo "password is empty";
exit();
}
$result = $db->prepare('SELECT * FROM users where user_name = :name');
$result->execute(array(
':user_name' => $name));
$count = $result->rowCount();
if( $count == 1 ) {
$row = $result->fetch();
if(password_verify($password,$row['password'])){
echo "Password verified and ok";
// initialize session if things where ok.
session_start();
//Prevent session fixation attack
session_regenerate_id();
$_SESSION['u_id'] = $row['user_id'];
$_SESSION['u_name'] = $row['user_name'];
header("location: ../index.php?login=success");
exit();
}
else{
echo "Wrong Password details";
}
}
else {
echo "User does not exist";
}
}
?>

Answer 2

I've made some fixes and added comments in to explain what changed:
LOGIN.INC.PHP
<?php
//First we start a session
session_start();
//Then we require the database connection
require_once 'dbh.inc.php';
// Removed the extra database connection here.
//We then check if the user has clicked the login button
if (isset($_POST['submit'])) {
//And we get the data from the login form
$name = $_POST['name'];
$password = $_POST['password'];
//Error handlers
//Error handlers are important to avoid any mistakes the user might have made when filling out the form!
//Check if inputs are empty
if (empty($name) || empty($password)) {
header("Location: ../index.php?login=empty");
exit();
}
//Removed extra 'else' here.
$stmt = $conn->prepare("SELECT * FROM users WHERE user_name=:name"); // Changed $db to $conn to use the connection from DBH.INC.PHP
$stmt->bindParam(':name', $name, PDO::PARAM_STR);
if (!$stmt->execute()) { // Added the ! to say "if this doesn't work, redirect to error"
header("location: ../index.php?login=error");
exit();
} else {
if ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
//de-hashing the password
$hashedpasswordCheck = password_verify($password, $row['user_password']);
if ($hashedpasswordCheck == false) {
header("location: ../index.php?login=error");
exit();
} else if ($hashedpasswordCheck == true) {
//Log in the user here
$_SESSION['u_id'] = $row['user_id'];
$_SESSION['u_name'] = $row['user_name'];
header("location: ../index.php?login=success");
exit();
}
} else {
header("location: ../index.php?login=error");
exit();
}
}
}
DB.INC.PHP
<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "loginsystem";
try {
$conn = new PDO("mysql:host=$servername;dbname=$dbname",
$username,
$password,
array(PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION));
// Removed the query and print of the databases
}
catch(PDOException $e) {
echo $e->getMessage();
}
// Removed the $conn=null to keep the connection we just set up.