brotkiste / php-auth

Authentication for PHP. Simple, lightweight and secure.

Auth

Authentication for PHP. Simple, lightweight and secure.

Written once, to be used everywhere.

Completely framework-agnostic and database-agnostic.

Why do I need this?

• There are tons of websites with weak authentication systems. Don't build such a site.
• Re-implementing a new authentication system for every PHP project is not a good idea.
• Building your own authentication classes piece by piece, and copying it to every project, is not recommended, either.
• A secure authentication system with an easy-to-use API should be thoroughly designed and planned.
• Peer-review for your critical infrastructure is a must.

Requirements

• PHP 5.6.0+
  • PDO (PHP Data Objects) extension (pdo)
    • MySQL Native Driver (mysqlnd) or SQLite driver (sqlite)
  • OpenSSL extension (openssl)
• MySQL 5.5.3+ or MariaDB 5.5.23+ or SQLite 3.14.1+ or other SQL databases that you create the schema for

Installation

1. Include the library via Composer:

   $ composer require delight-im/auth
   

2. Include the Composer autoloader:

   require __DIR__ . '/vendor/autoload.php';

3. Set up a database and create the required tables:

   • MySQL
   • SQLite

Upgrading

Migrating from an earlier version of this project? See our upgrade guide for help.

Usage

• Creating a new instance
• Registration (sign up)
• Login (sign in)
• Email verification
• Keeping the user logged in
• Password reset ("forgot password")
• Changing the current user's password
• Logout
• Accessing user information
  • Login state
  • User ID
  • Email address
  • Display name
  • Checking whether the user was "remembered"
  • IP address
  • Additional user information
• Administration (managing users)
  • Creating new users
  • Deleting users
• Utilities
  • Creating a random string
  • Creating a UUID v4 as per RFC 4122
• Reading and writing session data

Creating a new instance

// $db = new PDO('mysql:dbname=my-database;host=localhost;charset=utf8mb4', 'my-username', 'my-password');
// or
// $db = new PDO('sqlite:../Databases/my-database.sqlite');

// or

// $db = new \Delight\Db\PdoDsn('mysql:dbname=my-database;host=localhost;charset=utf8mb4', 'my-username', 'my-password');
// or
// $db = new \Delight\Db\PdoDsn('sqlite:../Databases/my-database.sqlite');

$auth = new \Delight\Auth\Auth($db);

If you have an open PDO connection already, just re-use it.

If you do enforce HTTPS on your site, pass true as the second parameter to the constructor. This is optional and the default is false.

Only in the very rare case that you need access to your cookies from JavaScript, pass true as the third argument to the constructor. This is optional and the default is false. There is almost always a better solution than enabling this, however.

If your web server is behind a proxy server and $_SERVER['REMOTE_ADDR'] only contains the proxy's IP address, you must pass the user's real IP address to the constructor in the fourth argument. The default is null.

Registration (sign up)

try {
    $userId = $auth->register($_POST['email'], $_POST['password'], $_POST['username'], function ($selector, $token) {
        // send `$selector` and `$token` to the user (e.g. via email)
    });

    // we have signed up a new user with the ID `$userId`
}
catch (\Delight\Auth\InvalidEmailException $e) {
    // invalid email address
}
catch (\Delight\Auth\InvalidPasswordException $e) {
    // invalid password
}
catch (\Delight\Auth\UserAlreadyExistsException $e) {
    // user already exists
}
catch (\Delight\Auth\TooManyRequestsException $e) {
    // too many requests
}

The username in the third parameter is optional. You can pass null there if you don't want to manage usernames.

If you want to enforce unique usernames, on the other hand, simply call registerWithUniqueUsername instead of register, and be prepared to catch the DuplicateUsernameException.

For email verification, you should build an URL with the selector and token and send it to the user, e.g.:

$url = 'https://www.example.com/verify_email?selector='.urlencode($selector).'&token='.urlencode($token);

If you don't want to perform email verification, just omit the last parameter to Auth#register. The new user will be active immediately, then.

Login (sign in)

try {
    $auth->login($_POST['email'], $_POST['password']);

    // user is logged in
}
catch (\Delight\Auth\InvalidEmailException $e) {
    // wrong email address
}
catch (\Delight\Auth\InvalidPasswordException $e) {
    // wrong password
}
catch (\Delight\Auth\EmailNotVerifiedException $e) {
    // email not verified
}
catch (\Delight\Auth\TooManyRequestsException $e) {
    // too many requests
}

If you want to sign in with usernames on the other hand, either in addition to the login via email address or as a replacement, that's possible as well. Simply call the method loginWithUsername instead of method login. Then, instead of catching InvalidEmailException, make sure to catch both UnknownUsernameException and AmbiguousUsernameException. You may also want to read the notes about the uniqueness of usernames in the section that explains how to sign up new users.

Email verification

Extract the selector and token from the URL that the user clicked on in the verification email.

try {
    $auth->confirmEmail($_GET['selector'], $_GET['token']);

    // email address has been verified
}
catch (\Delight\Auth\InvalidSelectorTokenPairException $e) {
    // invalid token
}
catch (\Delight\Auth\TokenExpiredException $e) {
    // token expired
}
catch (\Delight\Auth\TooManyRequestsException $e) {
    // too many requests
}

Keeping the user logged in

The third parameter to the Auth#login method controls whether the login is persistent with a long-lived cookie. With such a persistent login, users may stay authenticated for a long time, even when the browser session has already been closed and the session cookies have expired. Typically, you'll want to keep the user logged in for weeks or months with this feature, which is known as "remember me" or "keep me logged in". Many users will find this more convenient, but it may be less secure if they leave their devices unattended.

if ($_POST['remember'] == 1) {
    // keep logged in for one year
    $rememberDuration = (int) (60 * 60 * 24 * 365.25);
}
else {
    // do not keep logged in after session ends
    $rememberDuration = null;
}

// ...

$auth->login($_POST['email'], $_POST['password'], $rememberDuration);

// ...

Without the persistent login, which is the default behavior, a user will only stay logged in until they close their browser, or as long as configured via session.cookie_lifetime and session.gc_maxlifetime in PHP.

Omit the third parameter or set it to null to disable the feature. Otherwise, you may ask the user whether they want to enable "remember me". This is usually done with a checkbox in your user interface. Use the input from that checkbox to decide between null and a pre-defined duration in seconds here, e.g. 60 * 60 * 24 * 365.25 for one year.

Password reset ("forgot password")

try {
    $auth->forgotPassword($_POST['email'], function ($selector, $token) {
        // send `$selector` and `$token` to the user (e.g. via email)
    });

    // request has been generated
}
catch (\Delight\Auth\InvalidEmailException $e) {
    // invalid email address
}
catch (\Delight\Auth\EmailNotVerifiedException $e) {
    // email not verified
}
catch (\Delight\Auth\TooManyRequestsException $e) {
    // too many requests
}

You should build an URL with the selector and token and send it to the user, e.g.:

$url = 'https://www.example.com/reset_password?selector='.urlencode($selector).'&token='.urlencode($token);

As the next step, users will click on the link that they received. Extract the selector and token from the URL.

If the selector/token pair is valid, let the user choose a new password:

if ($auth->canResetPassword($_POST['selector'], $_POST['token'])) {
    // put the selector into a `hidden` field (or keep it in the URL)
    // put the token into a `hidden` field (or keep it in the URL)

    // ask the user for their new password
}

Now when you have the new password for the user (and still have the other two pieces of information), you can reset the password:

try {
    $auth->resetPassword($_POST['selector'], $_POST['token'], $_POST['password']);

    // password has been reset
}
catch (\Delight\Auth\InvalidSelectorTokenPairException $e) {
    // invalid token
}
catch (\Delight\Auth\TokenExpiredException $e) {
    // token expired
}
catch (\Delight\Auth\InvalidPasswordException $e) {
    // invalid password
}
catch (\Delight\Auth\TooManyRequestsException $e) {
    // too many requests
}

Changing the current user's password

If a user is currently logged in, they may change their password.

try {
    $auth->changePassword($_POST['oldPassword'], $_POST['newPassword']);

    // password has been changed
}
catch (\Delight\Auth\NotLoggedInException $e) {
    // not logged in
}
catch (\Delight\Auth\InvalidPasswordException $e) {
    // invalid password(s)
}

Logout

$auth->logout();

// user has been signed out

Accessing user information

Login state

if ($auth->isLoggedIn()) {
    // user is signed in
}
else {
    // user is *not* signed in yet
}

A shorthand/alias for this method is $auth->check().

User ID

$id = $auth->getUserId();

If the user is not currently signed in, this returns null.

A shorthand/alias for this method is $auth->id().

Email address

$email = $auth->getEmail();

If the user is not currently signed in, this returns null.

Display name

$email = $auth->getUsername();

Remember that usernames are optional and there is only a username if you supplied it during registration.

If the user is not currently signed in, this returns null.

Status information

if ($auth->isNormal()) {
    // user is in default state
}

if ($auth->isArchived()) {
    // user has been archived
}

if ($auth->isBanned()) {
    // user has been banned
}

if ($auth->isLocked()) {
    // user has been locked
}

if ($auth->isPendingReview()) {
    // user is pending review
}

if ($auth->isSuspended()) {
    // user has been suspended
}

Checking whether the user was "remembered"

if ($auth->isRemembered()) {
    // user did not sign in but was logged in through their long-lived cookie
}
else {
    // user signed in manually
}

If the user is not currently signed in, this returns null.

IP address

$ip = $auth->getIpAddress();

Additional user information

In order to preserve this library's suitability for all purposes as well as its full re-usability, it doesn't come with additional bundled columns for user information. But you don't have to do without additional user information, of course:

Here's how to use this library with your own tables for custom user information in a maintainable and re-usable way:

1. Add any number of custom database tables where you store custom user information, e.g. a table named profiles.

2. Whenever you call the register method (which returns the new user's ID), add your own logic afterwards that fills your custom database tables.

3. If you need the custom user information only rarely, you may just retrieve it as needed. If you need it more frequently, however, you'd probably want to have it in your session data. The following method is how you can load and access your data in a reliable way:

   function getUserInfo(\Delight\Auth\Auth $auth) {
       if (!$auth->isLoggedIn()) {
           return null;
       }
   
       if (!isset($_SESSION['_internal_user_info'])) {
           // TODO: load your custom user information and assign it to the session variable below
           // $_SESSION['_internal_user_info'] = ...
       }
   
       return $_SESSION['_internal_user_info'];
   }

Administration (managing users)

The administrative interface is available via $auth->admin(). You can call various method on this interface, as documented below.

Do not forget to implement secure access control before exposing access to this interface. For example, you may provide access to this interface to logged in users with the administrator role only, or use the interface in private scripts only.

Creating new users

try {
    $userId = $auth->admin()->createUser($_POST['email'], $_POST['password'], $_POST['username']);

    // we have signed up a new user with the ID `$userId`
}
catch (\Delight\Auth\InvalidEmailException $e) {
    // invalid email address
}
catch (\Delight\Auth\InvalidPasswordException $e) {
    // invalid password
}
catch (\Delight\Auth\UserAlreadyExistsException $e) {
    // user already exists
}

The username in the third parameter is optional. You can pass null there if you don't want to manage usernames.

If you want to enforce unique usernames, on the other hand, simply call createUserWithUniqueUsername instead of createUser, and be prepared to catch the DuplicateUsernameException.

Deleting users

Deleting users by their ID:

try {
    $auth->admin()->deleteUserById($_POST['id']);
}
catch (\Delight\Auth\UnknownIdException $e) {
    // unknown ID
}

Deleting users by their email address:

try {
    $auth->admin()->deleteUserByEmail($_POST['email']);
}
catch (\Delight\Auth\InvalidEmailException $e) {
    // unknown email address
}

Deleting users by their username:

try {
    $auth->admin()->deleteUserByUsername($_POST['username']);
}
catch (\Delight\Auth\UnknownUsernameException $e) {
    // unknown username
}
catch (\Delight\Auth\AmbiguousUsernameException $e) {
    // ambiguous username
}

Utilities

Creating a random string

$length = 24;
$randomStr = \Delight\Auth\Auth::createRandomString($length);

Creating a UUID v4 as per RFC 4122

$uuid = \Delight\Auth\Auth::createUuid();

Reading and writing session data

For detailed information on how to read and write session data conveniently, please refer to the documentation of the session library, which is included by default.

Frequently asked questions

What about password hashing?

Any password or authentication token is automatically hashed using the "bcrypt" function, which is based on the "Blowfish" cipher and (still) considered one of the strongest password hash functions today. "bcrypt" is used with 1,024 iterations, i.e. a "cost" factor of 10. A random "salt" is applied automatically as well.

You can verify this configuration by looking at the hashes in your database table users. If the above is true with your setup, all password hashes in your users table should start with the prefix $2$10$, $2a$10$ or $2y$10$.

When new algorithms (such as Argon2) may be introduced in the future, this library will automatically take care of "upgrading" your existing password hashes whenever a user signs in or changes their password.

How can I implement custom password requirements?

Enforcing a minimum length for passwords is usually a good idea. Apart from that, you may want to look up whether a potential password is in some blacklist, which you could manage in a database or in a file, in order to prevent dictionary words or commonly used passwords from being used in your application.

To allow for maximum flexibility and ease of use, this library has been designed so that it does not contain any further checks for password requirements itself, but instead allows you to wrap your own checks around the relevant calls to library methods. Example:

function isPasswordAllowed($password) {
    if (strlen($password) < 8) {
        return false;
    }

    $blacklist = [ 'password1', '123456', 'qwerty' ];

    if (in_array($password, $blacklist)) {
        return false;
    }

    return true;
}

if (isPasswordAllowed($password)) {
    $auth->register($email, $password);
}

Exceptions

This library throws two types of exceptions to indicate problems:

• AuthException and its subclasses are thrown whenever a method does not complete successfully. You should always catch these exceptions as they carry the normal error responses that you must react to.
• AuthError and its subclasses are thrown whenever there is an internal problem or the library has not been installed correctly. You should not catch these exceptions.

General advice

• Serve all pages over HTTPS only, i.e. using SSL/TLS for every single request.
• You should enforce a minimum length for passwords, e.g. 10 characters, but never any maximum length, at least not anywhere below 100 characters. Moreover, you should not restrict the set of allowed characters.
• Whenever a user was remembered through the "remember me" feature enabled or disabled during sign in, which means that they did not log in by typing their password, you should require re-authentication for critical features.
• Encourage users to use passphrases, i.e. combinations of words or even full sentences, instead of single passwords.
• Do not prevent users' password managers from working correctly. Thus, use the standard form fields only and do not prevent copy and paste.
• Before executing sensitive account operations (e.g. changing a user's email address, deleting a user's account), you should always require re-authentication, i.e. require the user to verify their login credentials once more.
• You should not offer an online password reset feature ("forgot password") for high-security applications.
• For high-security applications, you should not use email addresses as identifiers. Instead, choose identifiers that are specific to the application and secret, e.g. an internal customer number.

Contributing

All contributions are welcome! If you wish to contribute, please create an issue first so that your feature, problem or question can be discussed.

License

This project is licensed under the terms of the MIT License.