Redirect to specific user page - php

Question

I committed a HUGE sin and did some copy and paste programming. I know, I know. BAD programmer! Unfortunately, I am not well versed in PHP and MySQL (although I have enrolled in several Udemy classes to remedy that), and I needed a log in system right away. So, I used the tut found here. Now, it works great, but I need the page to redirect to a user specific page on log in, instead of to a single static page as found in the tut.
I added a column to my database at the end called page and populated it with the full URL I want for each user, and tried to change the code to get the value of the page column along with several other solutions from my little knowledge of PHP and things I found online and on SO, but I cannot seem to get the value from the database column "page" for the redirect. It just shows a blank page.
Here is the code that seems to be relevant:
<?php
include_once 'db_connect.php';
include_once 'functions.php';
sec_session_start();
if (isset($_POST['email'], $_POST['p'])) {
$email = $_POST['email'];
$password = $_POST['p'];
if (login($email, $password, $mysqli) == true) {
// Login success
header('Location: ../selection.php');
exit();
} else {
// Login failed
header('Location: ../error.php?error=1');
}
} else {
// The correct POST variables were not sent to this page.
echo 'Invalid Request';
}
and (I am not actually sure if this is relevant, but I didn't want anyone to have to go to the tutorial if I could prevent it)
<?php
include_once 'psl-config.php';
function sec_session_start() {
$session_name = 'sec_session_id'; // Set a custom session name
$secure = SECURE;
// This stops JavaScript being able to access the session id.
$httponly = true;
// Forces sessions to only use cookies.
if (ini_set('session.use_only_cookies', 1) === FALSE) {
header("Location: ../error.php?err=Could not initiate a safe session (ini_set)");
exit();
}
// Gets current cookies params.
$cookieParams = session_get_cookie_params();
session_set_cookie_params($cookieParams["lifetime"],
$cookieParams["path"],
$cookieParams["domain"],
$secure,
$httponly);
// Sets the session name to the one set above.
session_name($session_name);
session_start(); // Start the PHP session
session_regenerate_id(); // regenerated the session, delete the old one.
}
function login($email, $password, $mysqli) {
// Using prepared statements means that SQL injection is not possible.
if ($stmt = $mysqli->prepare("SELECT id, username, password, salt
FROM members
WHERE email = ?
LIMIT 1")) {
$stmt->bind_param('s', $email); // Bind "$email" to parameter.
$stmt->execute(); // Execute the prepared query.
$stmt->store_result();
// get variables from result.
$stmt->bind_result($user_id, $username, $db_password, $salt);
$stmt->fetch();
// hash the password with the unique salt.
$password = hash('sha512', $password . $salt);
if ($stmt->num_rows == 1) {
// If the user exists we check if the account is locked
// from too many login attempts
if (checkbrute($user_id, $mysqli) == true) {
// Account is locked
// Send an email to user saying their account is locked
return false;
} else {
// Check if the password in the database matches
// the password the user submitted.
if ($db_password == $password) {
// Password is correct!
// Get the user-agent string of the user.
$user_browser = $_SERVER['HTTP_USER_AGENT'];
// XSS protection as we might print this value
$user_id = preg_replace("/[^0-9]+/", "", $user_id);
$_SESSION['user_id'] = $user_id;
// XSS protection as we might print this value
$username = preg_replace("/[^a-zA-Z0-9_\-]+/",
"",
$username);
$_SESSION['username'] = $username;
$_SESSION['login_string'] = hash('sha512',
$password . $user_browser);
// Login successful.
return true;
} else {
// Password is not correct
// We record this attempt in the database
$now = time();
$mysqli->query("INSERT INTO login_attempts(user_id, time)
VALUES ('$user_id', '$now')");
return false;
}
}
} else {
// No user exists.
return false;
}
}
}
function checkbrute($user_id, $mysqli) {
// Get timestamp of current time
$now = time();
// All login attempts are counted from the past 2 hours.
$valid_attempts = $now - (2 * 60 * 60);
if ($stmt = $mysqli->prepare("SELECT time
FROM login_attempts
WHERE user_id = ?
AND time > '$valid_attempts'")) {
$stmt->bind_param('i', $user_id);
// Execute the prepared query.
$stmt->execute();
$stmt->store_result();
// If there have been more than 5 failed logins
if ($stmt->num_rows > 5) {
return true;
} else {
return false;
}
}
}
function login_check($mysqli) {
// Check if all session variables are set
if (isset($_SESSION['user_id'],
$_SESSION['username'],
$_SESSION['login_string'])) {
$user_id = $_SESSION['user_id'];
$login_string = $_SESSION['login_string'];
$username = $_SESSION['username'];
// Get the user-agent string of the user.
$user_browser = $_SERVER['HTTP_USER_AGENT'];
if ($stmt = $mysqli->prepare("SELECT password
FROM members
WHERE id = ? LIMIT 1")) {
// Bind "$user_id" to parameter.
$stmt->bind_param('i', $user_id);
$stmt->execute(); // Execute the prepared query.
$stmt->store_result();
if ($stmt->num_rows == 1) {
// If the user exists get variables from result.
$stmt->bind_result($password);
$stmt->fetch();
$login_check = hash('sha512', $password . $user_browser);
if ($login_check == $login_string) {
// Logged In!!!!
return true;
} else {
// Not logged in
return false;
}
} else {
// Not logged in
return false;
}
} else {
// Not logged in
return false;
}
} else {
// Not logged in
return false;
}
}
function esc_url($url) {
if ('' == $url) {
return $url;
}
$url = preg_replace('|[^a-z0-9-~+_.?#=!&;,/:%#$\|*\'()\\x80-\\xff]|i', '', $url);
$strip = array('%0d', '%0a', '%0D', '%0A');
$url = (string) $url;
$count = 1;
while ($count) {
$url = str_replace($strip, '', $url, $count);
}
$url = str_replace(';//', '://', $url);
$url = htmlentities($url);
$url = str_replace('&', '&', $url);
$url = str_replace("'", ''', $url);
if ($url[0] !== '/') {
// We're only interested in relative links from $_SERVER['PHP_SELF']
return '';
} else {
return $url;
}
}
I looked at the PHP.net docs, and have tried several solutions I found online, but nothing I have found seems to be working. Do I need to create a function for this? I know I need a better fundamental knowledge of PHP and MySQL for sure.
Let me know if you need more info on this.
Thanks!

Answer 1

Change your login function to also get the page-column (SELECT id, ..., page FROM ...)
Next, change the bind_result: add a parameter after $salt: ..., $salt, $page
Change the return true to return $page;
Now back in your script that calls the login function, change
if (login($email, $password, $mysqli) == true) {
// Login success
header('Location: ../selection.php');
to
$page = login($email, $password, $mysqli);
if ($page !== false) {
// Login success
header('Location: '. $page);
Make sure that your page-column contains valid values at all times though.