.. _security-access-control-explanation: How Does the Security access_control Work? ========================================== For each incoming request, Symfony checks each ``access_control`` entry to find *one* that matches the current request. As soon as it finds a matching ``access_control`` entry, it stops - only the **first** matching ``access_control`` is used to enforce access. Each ``access_control`` has several options that configure two different things: #. :ref:`should the incoming request match this access control entry ` #. :ref:`once it matches, should some sort of access restriction be enforced `: .. _security-access-control-matching-options: 1. Matching Options ------------------- Symfony creates an instance of :class:`Symfony\\Component\\HttpFoundation\\RequestMatcher` for each ``access_control`` entry, which determines whether or not a given access control should be used on this request. The following ``access_control`` options are used for matching: * ``path``: a regular expression (without delimiters) * ``ip`` or ``ips``: netmasks are also supported * ``port``: an integer * ``host``: a regular expression * ``methods``: one or many methods Take the following ``access_control`` entries as an example: .. configuration-block:: .. code-block:: yaml # config/packages/security.yaml security: # ... access_control: - { path: '^/admin', roles: ROLE_USER_IP, ip: 127.0.0.1 } - { path: '^/admin', roles: ROLE_USER_PORT, ip: 127.0.0.1, port: 8080 } - { path: '^/admin', roles: ROLE_USER_HOST, host: symfony\.com$ } - { path: '^/admin', roles: ROLE_USER_METHOD, methods: [POST, PUT] } .. code-block:: xml .. code-block:: php // config/packages/security.php $container->loadFromExtension('security', [ // ... 'access_control' => [ [ 'path' => '^/admin', 'roles' => 'ROLE_USER_IP', 'ips' => '127.0.0.1', ], [ 'path' => '^/admin', 'roles' => 'ROLE_USER_PORT', 'ip' => '127.0.0.1', 'port' => '8080', ], [ 'path' => '^/admin', 'rolse' => 'ROLE_USER_HOST', 'host' => 'symfony\.com$', ], [ 'path' => '^/admin', 'roles' => 'ROLE_USER_METHOD', 'methods' => 'POST, PUT', ] ], ]); For each incoming request, Symfony will decide which ``access_control`` to use based on the URI, the client's IP address, the incoming host name, and the request method. Remember, the first rule that matches is used, and if ``ip``, ``port``, ``host`` or ``method`` are not specified for an entry, that ``access_control`` will match any ``ip``, ``port``, ``host`` or ``method``: +-----------------+-------------+-------------+-------------+------------+--------------------------------+-------------------------------------------------------------+ | URI | IP | PORT | HOST | METHOD | ``access_control`` | Why? | +=================+=============+=============+=============+============+================================+=============================================================+ | ``/admin/user`` | 127.0.0.1 | 80 | example.com | GET | rule #1 (``ROLE_USER_IP``) | The URI matches ``path`` and the IP matches ``ip``. | +-----------------+-------------+-------------+-------------+------------+--------------------------------+-------------------------------------------------------------+ | ``/admin/user`` | 127.0.0.1 | 80 | symfony.com | GET | rule #1 (``ROLE_USER_IP``) | The ``path`` and ``ip`` still match. This would also match | | | | | | | | the ``ROLE_USER_HOST`` entry, but *only* the **first** | | | | | | | | ``access_control`` match is used. | +-----------------+-------------+-------------+-------------+------------+--------------------------------+-------------------------------------------------------------+ | ``/admin/user`` | 127.0.0.1 | 8080 | symfony.com | GET | rule #2 (``ROLE_USER_PORT``) | The ``path``, ``ip`` and ``port`` match. | +-----------------+-------------+-------------+-------------+------------+--------------------------------+-------------------------------------------------------------+ | ``/admin/user`` | 168.0.0.1 | 80 | symfony.com | GET | rule #3 (``ROLE_USER_HOST``) | The ``ip`` doesn't match the first rule, so the second | | | | | | | | rule (which matches) is used. | +-----------------+-------------+-------------+-------------+------------+--------------------------------+-------------------------------------------------------------+ | ``/admin/user`` | 168.0.0.1 | 80 | symfony.com | POST | rule #3 (``ROLE_USER_HOST``) | The second rule still matches. This would also match the | | | | | | | | third rule (``ROLE_USER_METHOD``), but only the **first** | | | | | | | | matched ``access_control`` is used. | +-----------------+-------------+-------------+-------------+------------+--------------------------------+-------------------------------------------------------------+ | ``/admin/user`` | 168.0.0.1 | 80 | example.com | POST | rule #4 (``ROLE_USER_METHOD``) | The ``ip`` and ``host`` don't match the first two entries, | | | | | | | | but the third - ``ROLE_USER_METHOD`` - matches and is used. | +-----------------+-------------+-------------+-------------+------------+--------------------------------+-------------------------------------------------------------+ | ``/foo`` | 127.0.0.1 | 80 | symfony.com | POST | matches no entries | This doesn't match any ``access_control`` rules, since its | | | | | | | | URI doesn't match any of the ``path`` values. | +-----------------+-------------+-------------+-------------+------------+--------------------------------+-------------------------------------------------------------+ .. caution:: Matching the URI is done without ``$_GET`` parameters. :ref:`Deny access in PHP code ` if you want to disallow access based on ``$_GET`` parameter values. .. _security-access-control-enforcement-options: 2. Access Enforcement --------------------- Once Symfony has decided which ``access_control`` entry matches (if any), it then *enforces* access restrictions based on the ``roles``, ``allow_if`` and ``requires_channel`` options: * ``roles`` If the user does not have the given role, then access is denied (internally, an :class:`Symfony\\Component\\Security\\Core\\Exception\\AccessDeniedException` is thrown). If this value is an array of multiple roles, the user must have at least one of them. * ``allow_if`` If the expression returns false, then access is denied; * ``requires_channel`` If the incoming request's channel (e.g. ``http``) does not match this value (e.g. ``https``), the user will be redirected (e.g. redirected from ``http`` to ``https``, or vice versa). .. tip:: Behind the scenes, the array value of ``roles`` is passed as the ``$attributes`` argument to each voter in the application with the :class:`Symfony\\Component\\HttpFoundation\\Request` as ``$subject``. You can learn how to use your custom attributes by reading :ref:`security/custom-voter`. .. caution:: If you define both ``roles`` and ``allow_if``, and your Access Decision Strategy is the default one (``affirmative``), then the user will be granted access if there's at least one valid condition. If this behavior doesn't fit your needs, :ref:`change the Access Decision Strategy `. .. tip:: If access is denied, the system will try to authenticate the user if not already (e.g. redirect the user to the login page). If the user is already logged in, the 403 "access denied" error page will be shown. See :doc:`/controller/error_pages` for more information. Matching access_control By IP ----------------------------- Certain situations may arise when you need to have an ``access_control`` entry that *only* matches requests coming from some IP address or range. For example, this *could* be used to deny access to a URL pattern to all requests *except* those from a trusted, internal server. .. caution:: As you'll read in the explanation below the example, the ``ips`` option does not restrict to a specific IP address. Instead, using the ``ips`` key means that the ``access_control`` entry will only match this IP address, and users accessing it from a different IP address will continue down the ``access_control`` list. Here is an example of how you configure some example ``/internal*`` URL pattern so that it is only accessible by requests from the local server itself: .. configuration-block:: .. code-block:: yaml # config/packages/security.yaml security: # ... access_control: # # the 'ips' option supports IP addresses and subnet masks - { path: '^/internal', roles: IS_AUTHENTICATED_ANONYMOUSLY, ips: [127.0.0.1, ::1, 192.168.0.1/24] } - { path: '^/internal', roles: ROLE_NO_ACCESS } .. code-block:: xml 127.0.0.1 ::1 .. code-block:: php // config/packages/security.php $container->loadFromExtension('security', [ // ... 'access_control' => [ [ 'path' => '^/internal', 'roles' => 'IS_AUTHENTICATED_ANONYMOUSLY', // the 'ips' option supports IP addresses and subnet masks 'ips' => ['127.0.0.1', '::1'], ], [ 'path' => '^/internal', 'roles' => 'ROLE_NO_ACCESS', ], ], ]); Here is how it works when the path is ``/internal/something`` coming from the external IP address ``10.0.0.1``: * The first access control rule is ignored as the ``path`` matches but the IP address does not match either of the IPs listed; * The second access control rule is enabled (the only restriction being the ``path``) and so it matches. If you make sure that no users ever have ``ROLE_NO_ACCESS``, then access is denied (``ROLE_NO_ACCESS`` can be anything that does not match an existing role, it just serves as a trick to always deny access). But if the same request comes from ``127.0.0.1`` or ``::1`` (the IPv6 loopback address): * Now, the first access control rule is enabled as both the ``path`` and the ``ip`` match: access is allowed as the user always has the ``IS_AUTHENTICATED_ANONYMOUSLY`` role. * The second access rule is not examined as the first rule matched. .. _security-allow-if: Securing by an Expression ~~~~~~~~~~~~~~~~~~~~~~~~~ Once an ``access_control`` entry is matched, you can deny access via the ``roles`` key or use more complex logic with an expression in the ``allow_if`` key: .. configuration-block:: .. code-block:: yaml # config/packages/security.yaml security: # ... access_control: - path: ^/_internal/secure # the 'role' and 'allow-if' options work like an OR expression, so # access is granted if the expression is TRUE or the user has ROLE_ADMIN roles: 'ROLE_ADMIN' allow_if: "'127.0.0.1' == request.getClientIp() or request.headers.has('X-Secure-Access')" .. code-block:: xml .. code-block:: php // config/packages/security.php $container->loadFromExtension('security', [ // ... 'access_control' => [ [ 'path' => '^/_internal/secure', // the 'role' and 'allow-if' options work like an OR expression, so // access is granted if the expression is TRUE or the user has ROLE_ADMIN 'roles' => 'ROLE_ADMIN', 'allow_if' => '"127.0.0.1" == request.getClientIp() or request.headers.has('X-Secure-Access')', ], ], ]); In this case, when the user tries to access any URL starting with ``/_internal/secure``, they will only be granted access if the IP address is ``127.0.0.1`` or a secure header, or if the user has the ``ROLE_ADMIN`` role. .. note:: Internally ``allow_if`` triggers the built-in :class:`Symfony\\Component\\Security\\Core\\Authorization\\Voter\\ExpressionVoter` as like it was part of the attributes defined in the ``roles`` option. Inside the expression, you have access to a number of different variables and functions including ``request``, which is the Symfony :class:`Symfony\\Component\\HttpFoundation\\Request` object (see :ref:`component-http-foundation-request`). For a list of the other functions and variables, see :ref:`functions and variables `. .. tip:: The ``allow_if`` expressions can also contain custom functions registered with :ref:`expression providers `. Restrict to a port ------------------ Add the ``port`` option to any ``access_control`` entries to require users to access those URLs via a specific port. This could be useful for example for ``localhost:8080``. .. configuration-block:: .. code-block:: yaml # config/packages/security.yaml security: # ... access_control: - { path: ^/cart/checkout, roles: IS_AUTHENTICATED_ANONYMOUSLY, port: 8080 } .. code-block:: xml .. code-block:: php // config/packages/security.php $container->loadFromExtension('security', [ // ... 'access_control' => [ [ 'path' => '^/cart/checkout', 'role' => 'IS_AUTHENTICATED_ANONYMOUSLY', 'port' => '8080', ], ], ]); Forcing a Channel (http, https) ------------------------------- You can also require a user to access a URL via SSL; use the ``requires_channel`` argument in any ``access_control`` entries. If this ``access_control`` is matched and the request is using the ``http`` channel, the user will be redirected to ``https``: .. configuration-block:: .. code-block:: yaml # config/packages/security.yaml security: # ... access_control: - { path: ^/cart/checkout, roles: IS_AUTHENTICATED_ANONYMOUSLY, requires_channel: https } .. code-block:: xml .. code-block:: php // config/packages/security.php $container->loadFromExtension('security', [ // ... 'access_control' => [ [ 'path' => '^/cart/checkout', 'roles' => 'IS_AUTHENTICATED_ANONYMOUSLY', 'requires_channel' => 'https', ], ], ]);