Using the new Authenticator-based Security

New in version 5.1: Authenticator-based security was introduced as an experimental feature in Symfony 5.1.

In Symfony 5.1, a new authentication system was introduced. This system changes the internals of Symfony Security, to make it more extensible and more understandable.

Enabling the System

The authenticator-based system can be enabled using the enable_authenticator_manager setting:

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    # config/packages/security.yaml
security:
    enable_authenticator_manager: true
    # ...
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    <!-- config/packages/security.xml -->
<?xml version="1.0" encoding="UTF-8"?>
<srv:container xmlns="http://symfony.com/schema/dic/security"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:srv="http://symfony.com/schema/dic/services"
    xsi:schemaLocation="http://symfony.com/schema/dic/services
        https://symfony.com/schema/dic/services/services-1.0.xsd
        http://symfony.com/schema/dic/security
        https://symfony.com/schema/dic/security/security-1.0.xsd">

    <config enable-authenticator-manager="true">
        <!-- ... -->
    </config>
</srv:container>
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    // config/packages/security.php
$container->loadFromExtension('security', [
    'enable_authenticator_manager' => true,
    // ...
]);

The new system is backwards compatible with the current authentication system, with some exceptions that will be explained in this article:

Adding Support for Unsecured Access (i.e. Anonymous Users)

In Symfony, visitors that haven’t yet logged in to your website were called anonymous users. The new system no longer has anonymous authentication. Instead, these sessions are now treated as unauthenticated (i.e. there is no security token). When using isGranted(), the result will always be false (i.e. denied) as this session is handled as a user without any privileges.

In the access_control configuration, you can use the new PUBLIC_ACCESS security attribute to whitelist some routes for unauthenticated access (e.g. the login page):

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    # config/packages/security.yaml
security:
    enable_authenticator_manager: true

    # ...
    access_control:
        # allow unauthenticated users to access the login form
        - { path: ^/admin/login, roles: PUBLIC_ACCESS }

        # but require authentication for all other admin routes
        - { path: ^/admin, roles: ROLE_ADMIN }
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    <!-- config/packages/security.xml -->
<?xml version="1.0" encoding="UTF-8"?>
<srv:container xmlns="http://symfony.com/schema/dic/security"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:srv="http://symfony.com/schema/dic/services"
    xsi:schemaLocation="http://symfony.com/schema/dic/services
        https://symfony.com/schema/dic/services/services-1.0.xsd
        http://symfony.com/schema/dic/security
        https://symfony.com/schema/dic/security/security-1.0.xsd">

    <config enable-authenticator-manager="true">
        <!-- ... -->

        <access-control>
            <!-- allow unauthenticated users to access the login form -->
            <rule path="^/admin/login" role="PUBLIC_ACCESS"/>

            <!-- but require authentication for all other admin routes -->
            <rule path="^/admin" role="ROLE_ADMIN"/>
        </access-control>
    </config>
</srv:container>
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    // config/packages/security.php
use Symfony\Component\Security\Http\Firewall\AccessListener;

$container->loadFromExtension('security', [
    'enable_authenticator_manager' => true,

    // ...
    'access_control' => [
        // allow unauthenticated users to access the login form
        ['path' => '^/admin/login', 'roles' => AccessListener::PUBLIC_ACCESS],

        // but require authentication for all other admin routes
        ['path' => '^/admin', 'roles' => 'ROLE_ADMIN'],
    ],
]);

Configuring the Authentication Entry Point

Sometimes, one firewall has multiple ways to authenticate (e.g. both a form login and an API token authentication). In these cases, it is now required to configure the authentication entry point. The entry point is used to generate a response when the user is not yet authenticated but tries to access a page that requires authentication. This can be used for instance to redirect the user to the login page.

You can configure this using the entry_point setting:

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    # config/packages/security.yaml
security:
    enable_authenticator_manager: true

    # ...
    firewalls:
        main:
            # allow authentication using a form or HTTP basic
            form_login: ~
            http_basic: ~

            # configure the form authentication as the entry point for unauthenticated users
            entry_point: form_login
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    <!-- config/packages/security.xml -->
<?xml version="1.0" encoding="UTF-8"?>
<srv:container xmlns="http://symfony.com/schema/dic/security"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:srv="http://symfony.com/schema/dic/services"
    xsi:schemaLocation="http://symfony.com/schema/dic/services
        https://symfony.com/schema/dic/services/services-1.0.xsd
        http://symfony.com/schema/dic/security
        https://symfony.com/schema/dic/security/security-1.0.xsd">

    <config enable-authenticator-manager="true">
        <!-- ... -->

        <!-- entry-point: configure the form authentication as the entry
                          point for unauthenticated users -->
        <firewall name="main"
            entry-point="form_login"
        >
            <!-- allow authentication using a form or HTTP basic -->
            <form-login/>
            <http-basic/>
    </config>
</srv:container>
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    // config/packages/security.php
use Symfony\Component\Security\Http\Firewall\AccessListener;

$container->loadFromExtension('security', [
    'enable_authenticator_manager' => true,

    // ...
    'firewalls' => [
        'main' => [
            // allow authentication using a form or HTTP basic
            'form_login' => null,
            'http_basic' => null,

            // configure the form authentication as the entry point for unauthenticated users
            'entry_point' => 'form_login'
        ],
    ],
]);

Note

You can also create your own authentication entry point by creating a class that implements AuthenticationEntryPointInterface. You can then set entry_point to the service id (e.g. entry_point: App\Security\CustomEntryPoint)

Creating a Custom Authenticator

Security traditionally could be extended by writing custom authentication providers. The authenticator-based system dropped support for these providers and introduced a new authenticator interface as a base for custom authentication methods.

Tip

Guard authenticators are still supported in the authenticator-based system. It is however recommended to also update these when you’re refactoring your application to the new system. The new authenticator interface has many similarities with the guard authenticator interface, making the rewrite easier.

Authenticators should implement the AuthenticatorInterface. You can also extend AbstractAuthenticator, which has a default implementation for the createAuthenticatedToken() method that fits most use-cases:

// src/Security/ApiKeyAuthenticator.php
namespace App\Security;

use App\Entity\User;
use Doctrine\ORM\EntityManagerInterface;
use Symfony\Component\HttpFoundation\JsonResponse;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\Security\Core\Authentication\Token\TokenInterface;
use Symfony\Component\Security\Core\Exception\AuthenticationException;
use Symfony\Component\Security\Core\Exception\CustomUserMessageAuthenticationException;
use Symfony\Component\Security\Core\Exception\UsernameNotFoundException;
use Symfony\Component\Security\Http\Authenticator\AbstractAuthenticator;
use Symfony\Component\Security\Http\Authenticator\Passport\PassportInterface;
use Symfony\Component\Security\Http\Authenticator\Passport\SelfValidatingPassport;

class ApiKeyAuthenticator extends AbstractAuthenticator
{
    private $entityManager;

    public function __construct(EntityManagerInterface $entityManager)
    {
        $this->entityManager = $entityManager;
    }

    /**
     * Called on every request to decide if this authenticator should be
     * used for the request. Returning `false` will cause this authenticator
     * to be skipped.
     */
    public function supports(Request $request): ?bool
    {
        return $request->headers->has('X-AUTH-TOKEN');
    }

    public function authenticate(Request $request): PassportInterface
    {
        $apiToken = $request->headers->get('X-AUTH-TOKEN');
        if (null === $apiToken) {
            // The token header was empty, authentication fails with HTTP Status
            // Code 401 "Unauthorized"
            throw new CustomUserMessageAuthenticationException('No API token provided');
        }

        $user = $this->entityManager->getRepository(User::class)
            ->findOneBy(['apiToken' => $apiToken])
        ;
        if (null === $user) {
            throw new UsernameNotFoundException();
        }

        return new SelfValidatingPassport($user);
    }

    public function onAuthenticationSuccess(Request $request, TokenInterface $token, string $firewallName): ?Response
    {
        // on success, let the request continue
        return null;
    }

    public function onAuthenticationFailure(Request $request, AuthenticationException $exception): ?Response
    {
        $data = [
            // you may want to customize or obfuscate the message first
            'message' => strtr($exception->getMessageKey(), $exception->getMessageData())

            // or to translate this message
            // $this->translator->trans($exception->getMessageKey(), $exception->getMessageData())
        ];

        return new JsonResponse($data, Response::HTTP_UNAUTHORIZED);
    }
}

The authenticator can be enabled using the custom_authenticators setting:

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    # config/packages/security.yaml
security:
    enable_authenticator_manager: true

    # ...
    firewalls:
        main:
            custom_authenticators:
                - App\Security\ApiKeyAuthenticator

            # don't forget to also configure the entry_point if the
            # authenticator implements AuthenticatorEntryPointInterface
            # entry_point: App\Security\CustomFormLoginAuthenticator
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    <!-- config/packages/security.xml -->
<?xml version="1.0" encoding="UTF-8"?>
<srv:container xmlns="http://symfony.com/schema/dic/security"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:srv="http://symfony.com/schema/dic/services"
    xsi:schemaLocation="http://symfony.com/schema/dic/services
        https://symfony.com/schema/dic/services/services-1.0.xsd
        http://symfony.com/schema/dic/security
        https://symfony.com/schema/dic/security/security-1.0.xsd">

    <config enable-authenticator-manager="true">
        <!-- ... -->

        <!-- don't forget to also configure the entry-point if the
             authenticator implements AuthenticatorEntryPointInterface
        <firewall name="main"
            entry-point="App\Security\CustomFormLoginAuthenticator"> -->

        <firewall name="main">
            <custom-authenticator>App\Security\ApiKeyAuthenticator</custom-authenticator>
        </firewall>
    </config>
</srv:container>
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    // config/packages/security.php
use App\Security\ApiKeyAuthenticator;
use Symfony\Component\Security\Http\Firewall\AccessListener;

$container->loadFromExtension('security', [
    'enable_authenticator_manager' => true,

    // ...
    'firewalls' => [
        'main' => [
            'custom_authenticators' => [
                ApiKeyAuthenticator::class,
            ],

            // don't forget to also configure the entry_point if the
            // authenticator implements AuthenticatorEntryPointInterface
            // 'entry_point' => [App\Security\CustomFormLoginAuthenticator::class],
        ],
    ],
]);

The authenticate() method is the most important method of the authenticator. Its job is to extract credentials (e.g. username & password, or API tokens) from the Request object and transform these into a security Passport.

Tip

If you want to customize the login form, you can also extend from the AbstractLoginFormAuthenticator class instead.

Security Passports

A passport is an object that contains the user that will be authenticated as well as other pieces of information, like whether a password should be checked or if “remember me” functionality should be enabled.

The default Passport. requires a user object and credentials. The following credential classes are supported by default:

PasswordCredentials
This requires a plaintext $password, which is validated using the password encoder configured for the user.
CustomCredentials

Allows a custom closure to check credentials:

// ...
return new Passport($user, new CustomCredentials(
    // If this function returns anything else than `true`, the credentials
    // are marked as invalid.
    // The $credentials parameter is equal to the next argument of this class
    function ($credentials, UserInterface $user) {
        return $user->getApiToken() === $credentials;
    },

    // The custom credentials
    $apiToken
));

Note

If you don’t need any credentials to be checked (e.g. a JWT token), you can use the SelfValidatingPassport. This class only requires a user and optionally Passport Badges.

Passport Badges

The Passport also optionally allows you to add security badges. Badges attach more data to the passport (to extend security). By default, the following badges are supported:

RememberMeBadge
When this badge is added to the passport, the authenticator indicates remember me is supported. Whether remember me is actually used depends on special remember_me configuration. Read How to Add “Remember Me” Login Functionality for more information.
PasswordUpgradeBadge
This is used to automatically upgrade the password to a new hash upon successful login. This badge requires the plaintext password and a password upgrader (e.g. the user repository). See How to Migrate a Password Hash.
CsrfTokenBadge
Automatically validates CSRF tokens for this authenticator during authentication. The constructor requires a token ID (unique per form) and CSRF token (unique per request). See How to Implement CSRF Protection.
PreAuthenticatedUserBadge
Indicates that this user was pre-authenticated (i.e. before Symfony was initiated). This skips the pre-authentication user checker.

For instance, if you want to add CSRF and password migration to your custom authenticator, you would initialize the passport like this:

// ...
use Symfony\Component\Security\Http\Authenticator\AbstractAuthenticator;
use Symfony\Component\Security\Http\Authenticator\Passport\Badge\CsrfTokenBadge;
use Symfony\Component\Security\Http\Authenticator\Passport\Badge\PasswordUpgradeBadge;
use Symfony\Component\Security\Http\Authenticator\Passport\Passport;
use Symfony\Component\Security\Http\Authenticator\Passport\PassportInterface;

class LoginAuthenticator extends AbstractAuthenticator
{
    public function authenticate(Request $request): PassportInterface
    {
        $password = $request->request->get('password');
        $username = $request->request->get('username');
        $csrfToken = $request->request->get('csrf_token');

        // ... get the $user from the $username and validate no
        // parameter is empty

        return new Passport($user, new PasswordCredentials($password), [
            // $this->userRepository must implement PasswordUpgraderInterface
            new PasswordUpgradeBadge($password, $this->userRepository),
            new CsrfTokenBadge('login', $csrfToken);
        ]);
    }
}