PHP form validation and XSS security - php

Question

Am new to php and am taking a web application development to allow come across different skill, problems and find a way to fix them.
Am now creating a registration form and validating the form and protecting it against SQL Injection and XSS. NOTE I understand could have use prepared statement, but for my level of skill i think starting from Mysqli procedural wold be best result for my development until if fill confident enough.
So i just want you the expert to see if there is something i needed to remove or add or use instead (apart from stmt).
Here is my Register page.
<?php
// define mqsqli real escape string function
function _olaskee($escape) {
$escape = htmlspecialchars ($escape, ENT_QUOTES, 'UTF-8');
$escape = trim ($escape, ENT_QUOTES, 'UTF-8');
$escape = stripcslashes ($escape, ENT_QUOTES, 'UTF-8');
return $escape;
}
// start session
session_start();
// include database connection
//require_once('include/connection.php');
// if user type already detected, redirect to index.php
if(isset($_SESSION['user_type'])){
header('Location: index.php');
}
// check if we have submited / if the for as being submitted
if(!empty($_POST['submit'])){
//instantiate
$firstname = _olaskee($con, $_POST['firstname']);
$lastname = _olaskee($con, $_POST['lastname']);
$user_name = _olaskee($con, $_POST['user_name']);
$user_type = _olaskee($con, $_POST['user_type']);
$password = _olaskee($con, $_POST['password']);
$confirm_password = _olaskee($con, $_POST['confirm_password']);
// hash password
$hashed_password = password_hash($password, PASSWORD_BCRYPT, ['cost' => 12]);
// include database connection
require_once('include/errMsg.php');
}
// include page title
$title = 'Registration Page';
// include header layout
require_once('include/header.php');
?>
<div>
<form name="register" action="<?php echo htmlspecialchars($_SERVER['PHP_SELF'], ENT_QUOTES, 'UTF-8'); ?>" method="post">
<table>
<tr>
<td>First Name</td>
<td><input type="text" name="firstname" value='<?php// echo htmlspecialchars ($firstname) ?>'><br><span style='color: red'><?php echo $fnErr ?></span></td>
<?php echo $firstname ; ?>
</tr>
<tr>
<td>Last Name</td>
<td><input type="text" name="lastname" value='<?php echo htmlspecialchars ($lastname) ?>'><br><span style='color: red'><?php echo $lnErr ?></span></td>
</tr>
<tr>
<td>User Name</td>
<td><input type="text" name="user_name" value='<?php echo htmlspecialchars ($user_name) ?>'><br><span style='color: red'><?php echo $unameErr ?></span></td>
</tr>
<tr>
<td>User Type</td>
<td>
<!-- <label for="flavor">Select User Type:</label > -->
<select id="user_type" name='user_type' >
<option value="">Select User Type</option>
<option <?php echo $user_type=='rsw'?'selected':''; ?> >rsw</option>
<option <?php echo $user_type=='sp'?'selected':''; ?> >sp</option>
</select>
<span style='color: red'><?php echo $u_typeErr?></span>
</td>
</tr>
<tr>
<td>Email</td>
<td><input type="email" name="email" value='<?php echo htmlspecialchars ($email) ?>'><br /><span style='color: red'><?php echo $emailErr ?></span></td>
</tr>
<tr>
<td>Password:</td>
<td><input type="password" name="password" id="password"><br /><span style='color: red'><?php echo $passErr ?></span></td></td>
</tr>
<tr>
<td>Confirm Password:</td>
<td><input type="password" name="confirm_password" id="confirm_password"><br /><span style='color: red'><?php echo $cpassErr ?></span></td></td>
</tr>
<tr>
<td></td>
<td><input type="submit" name="submit" value="Register"><a href='index.php'> Login</a></td>
</tr>
</table>
</form>
</div>
<?php
if(is_file('include/footer.php'))
include_once('include/footer.php');
?>
And here is my error message page
<?php
// error handler variable
$fnErr = $lnErr = $unameErr = $u_typeErr = $emailErr = $passErr = $cpassErr = '';
$firstname = $lastname = $user_name = $user_type = $email = $password = $confirm_password = '';
// if submit, then validate
$firstname = ($_POST['firstname']);
// set field validation for first name
if (empty($firstname)){
$fnErr = 'Field empty, please enter your first name';
}else{
if (strlen($firstname) < 3){
$fnErr = 'First Name is too short';
}
}
// check if name only contains letters and whitespace
if (!preg_match("/^[a-zA-Z ]*$/",$firstname)) {
$fnErr = "Only letters and white space allowed";
}
// set field validation for last name
$lastname = ($_POST['lastname']);
if (empty($lastname)){
$lnErr = 'Field empty, please enter your last name';
}else{
if (strlen($lastname) < 3){
$lnErr = 'Last Name is too short';
}
}
// check if name only contains letters and whitespace
if (!preg_match("/^[a-zA-Z ]*$/",$lastname)) {
$lnErr = "Only letters and white space allowed";
}
// set field validation for user name
$user_name = ($_POST['user_name']);
if (empty($user_name)){
$unameErr = 'Field empty, please enter user name';
}else{
if (strlen($user_name) < 6){
$unameErr = 'Password is too short';
}else{
if (strlen($user_name) > 15){
$unameErr = 'Password is too long';
}
}
}
// check if name only contains letters and whitespace
if (!preg_match("#.*^(?=.*[a-z])(?=.*[A-Z]).*$#",$user_name)) {
$unameErr = "At least one CAPS, letters and white space allow";
}
// check if user select user type from list
$user_type = ($_POST['user_type']);
if (empty($user_type)){
$u_typeErr = 'Please select user type from list';
}
// set email filter validation
$email = ($_POST['email']);
if (empty($email)){
$emailErr = 'Field empty, please enter your last name';
}else{
// check if e-mail address is well-formed
if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
$emailErr = "Invalid email format";
}
}
// set field validation for password
$password = ($_POST['password']);
if (empty($password)){
$passErr = 'Field empty, please create a password';
}else{
if (strlen($password) < 6){
$passErr = 'Password is too short';
}else{
if (strlen($password) > 15){
$passErr = 'Password is too long';
}
}
}
if( !preg_match("#[A-Z]+#", $password) ) {
$passErr = "Password must include at least one CAPS! ";
}else{
if( !preg_match("#[0-9]+#", $password) ) {
$passErr = "Password must include at least one NUMBER! ";
}
}
// // // check if name only contains letters and whitespace
// if (preg_match("#.*^(?=.*[a-z])(?=.*[A-Z])(?=.*[0-9]).*$#", $password)) {
// $passErr = "Try again... Password must contain NUMBER, LETTER and CAPS";
// }
// set field validation for confirm password
$confirm_password = ($_POST['confirm_password']);
if (empty($confirm_password)){
$cpassErr = 'Field empty, please confirm your password';
}else{
if ($password != $confirm_password) {
$cpassErr = 'Error... Passwords do not match';
}
}
// // define mqsqli real escape string function
// function _olaskee($escape) {
// $escape = htmlspecialchars ($escape, ENT_QUOTES, 'UTF-8');
// $escape = trim ($escape, ENT_QUOTES, 'UTF-8');
// $escape = stripcslashes ($escape, ENT_QUOTES, 'UTF-8');
// return $escape;
// }
?>
NOTE have commented out some lines in both pages.
Also in the register page have include the security function at the top of the session unsure if that's right.
Also have used the password hashing, but i haven't test in on database yet, but (have i used it right?)
Please just have a look and give me your expert opinion
Best Regards

Answer 1

I am not an expert but I can give you some notes. In your sanitizing function _olaskee, I think you need to understand what these functions does and how to use it
You don't need stripcslashes here. This function removes the slashes why are you putting it here?
You don't need to sanitize the password. You will be hashing it before using it and hashing will replace any injected code
For sanitizing against SQL Injection you need to use mysqli_real_escape_string It will take care of sanitizing strings.
Take a look at filter_var function. You will find it very useful in sanitizing and validating your inputs. This function allows you to validate against a specified length, allow some HTML tags in certain inputs (like textarea) and so on
To understand how to protect yourself from attacks you need to know first how the attacks are made. Read about SQL Injections and see if you can hack your database through vulnerable code.
You may try also try ZAP tool. You can use automatic scan by just passing the URL of your site and it will automatically scan your web app and report any vulnerabilities it finds
It is good to learn how to make a login system. But for real world applications, it is not advised to make your own login system. Always rely on tested and approved software or you will be creating systems full of vulnerabilities. Good luck!