add ability to read cookie secret from config

docs/configuration.rst

@@ -50,6 +50,7 @@ Base authorization settings. ``OAuth`` provider requires ``aioauth-client`` libr
 * ``allow_read_only`` - allow requesting status APIs without authorization, boolean, required.
 * ``client_id`` - OAuth2 application client ID, string, required in case if ``oauth`` is used.
 * ``client_secret`` - OAuth2 application client secret key, string, required in case if ``oauth`` is used.
+* ``cookie_secret_key`` - secret key which will be used for cookies encryption, string, optional. It must be 32 url-safe base64-encoded bytes and can be generated as following ``base64.urlsafe_b64encode(os.urandom(32)).decode("utf8")``. If not set, it will be generated automatically; note, however, that in this case, all sessions will be automatically expired during restart.
 * ``max_age`` - parameter which controls both cookie expiration and token expiration inside the service, integer, optional, default is 7 days.
 * ``oauth_provider`` - OAuth2 provider class name as is in ``aioauth-client`` (e.g. ``GoogleClient``, ``GithubClient`` etc), string, required in case if ``oauth`` is used.
 * ``oauth_scopes`` - scopes list for OAuth2 provider, which will allow retrieving user email (which is used for checking user permissions), e.g. ``https://www.googleapis.com/auth/userinfo.email`` for ``GoogleClient`` or ``user:email`` for ``GithubClient``, space separated list of strings, required in case if ``oauth`` is used.

src/ahriman/core/configuration/schema.py

@@ -109,6 +109,9 @@ CONFIGURATION_SCHEMA: ConfigurationSchema = {
             "client_secret": {
                 "type": "string",
             },
+            "cookie_secret_key": {
+                "type": "string",
+            },
             "max_age": {
                 "type": "integer",
                 "coerce": "integer",

src/ahriman/web/middlewares/auth_handler.py

@@ -18,7 +18,6 @@
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 #
 import aiohttp_security  # type: ignore
-import base64
 import socket
 import types
 
@@ -32,12 +31,13 @@ from cryptography import fernet
 from typing import Optional
 
 from ahriman.core.auth import Auth
+from ahriman.core.configuration import Configuration
 from ahriman.models.user_access import UserAccess
 from ahriman.models.user_identity import UserIdentity
 from ahriman.web.middlewares import HandlerType, MiddlewareType
 
 
-__all__ = ["AuthorizationPolicy", "auth_handler", "setup_auth"]
+__all__ = ["AuthorizationPolicy", "auth_handler", "cookie_secret_key", "setup_auth"]
 
 
 class AuthorizationPolicy(aiohttp_security.AbstractAuthorizationPolicy):  # type: ignore
@@ -125,19 +125,36 @@ def auth_handler(allow_read_only: bool) -> MiddlewareType:
     return handle
 
 
-def setup_auth(application: web.Application, validator: Auth) -> web.Application:
+def cookie_secret_key(configuration: Configuration) -> fernet.Fernet:
+    """
+    extract cookie secret key from configuration if set or generate new one
+
+    Args:
+        configuration(Configuration): configuration instance
+
+    Returns:
+        fernet.Fernet: fernet key instance
+    """
+    if (secret_key := configuration.get("auth", "cookie_secret_key", fallback=None)) is not None:
+        return fernet.Fernet(secret_key)
+
+    secret_key = fernet.Fernet.generate_key()
+    return fernet.Fernet(secret_key)
+
+
+def setup_auth(application: web.Application, configuration: Configuration, validator: Auth) -> web.Application:
     """
     setup authorization policies for the application
 
     Args:
         application(web.Application): web application instance
+        configuration(Configuration): configuration instance
         validator(Auth): authorization module instance
 
     Returns:
         web.Application: configured web application
     """
-    fernet_key = fernet.Fernet.generate_key()
-    secret_key = base64.urlsafe_b64decode(fernet_key)
+    secret_key = cookie_secret_key(configuration)
     storage = EncryptedCookieStorage(secret_key, cookie_name="API_SESSION", max_age=validator.max_age)
     setup_session(application, storage)
 

src/ahriman/web/web.py

@@ -168,6 +168,6 @@ def setup_service(architecture: str, configuration: Configuration, spawner: Spaw
     validator = application["validator"] = Auth.load(configuration, database)
     if validator.enabled:
         from ahriman.web.middlewares.auth_handler import setup_auth
-        setup_auth(application, validator)
+        setup_auth(application, configuration, validator)
 
     return application

tests/ahriman/web/middlewares/test_auth_handler.py

@@ -3,14 +3,16 @@ import socket
 
 from aiohttp import web
 from aiohttp.test_utils import TestClient
+from cryptography import fernet
 from pytest_mock import MockerFixture
 from unittest.mock import AsyncMock
 
 from ahriman.core.auth import Auth
+from ahriman.core.configuration import Configuration
 from ahriman.models.user import User
 from ahriman.models.user_access import UserAccess
 from ahriman.models.user_identity import UserIdentity
-from ahriman.web.middlewares.auth_handler import auth_handler, AuthorizationPolicy, setup_auth
+from ahriman.web.middlewares.auth_handler import AuthorizationPolicy, auth_handler, cookie_secret_key, setup_auth
 
 
 def _identity(username: str) -> str:
@@ -175,11 +177,28 @@ async def test_auth_handler_write(mocker: MockerFixture) -> None:
         check_permission_mock.assert_called_once_with(aiohttp_request, UserAccess.Full, aiohttp_request.path)
 
 
-def test_setup_auth(application_with_auth: web.Application, auth: Auth, mocker: MockerFixture) -> None:
+def test_cookie_secret_key(configuration: Configuration) -> None:
+    """
+    must generate fernet key
+    """
+    secret_key = cookie_secret_key(configuration)
+    assert isinstance(secret_key, fernet.Fernet)
+
+
+def test_cookie_secret_key_cached(configuration: Configuration) -> None:
+    """
+    must use cookie key as set by configuration
+    """
+    configuration.set_option("auth", "cookie_secret_key", fernet.Fernet.generate_key().decode("utf8"))
+    assert cookie_secret_key(configuration) is not None
+
+
+def test_setup_auth(application_with_auth: web.Application, configuration: Configuration, auth: Auth,
+                    mocker: MockerFixture) -> None:
     """
     must set up authorization
     """
     setup_mock = mocker.patch("aiohttp_security.setup")
-    application = setup_auth(application_with_auth, auth)
+    application = setup_auth(application_with_auth, configuration, auth)
     assert application.get("validator") is not None
     setup_mock.assert_called_once_with(application_with_auth, pytest.helpers.anyvar(int), pytest.helpers.anyvar(int))