From 1d8b80b3346b31a297668e093fb813d9ce7a1b48 Mon Sep 17 00:00:00 2001 From: reivilibre Date: Fri, 26 Nov 2021 14:27:14 +0000 Subject: [PATCH] Support expiry of refresh tokens and expiry of the overall session when refresh tokens are in use. (#11425) --- changelog.d/11425.feature | 1 + synapse/config/registration.py | 24 +--- synapse/handlers/auth.py | 90 +++++++++++-- synapse/handlers/register.py | 44 ++++-- synapse/rest/client/login.py | 52 +++++--- .../storage/databases/main/registration.py | 28 +++- .../delta/65/10_expirable_refresh_tokens.sql | 28 ++++ tests/rest/client/test_auth.py | 125 +++++++++++++++++- 8 files changed, 338 insertions(+), 54 deletions(-) create mode 100644 changelog.d/11425.feature create mode 100644 synapse/storage/schema/main/delta/65/10_expirable_refresh_tokens.sql diff --git a/changelog.d/11425.feature b/changelog.d/11425.feature new file mode 100644 index 000000000..806dd5d91 --- /dev/null +++ b/changelog.d/11425.feature @@ -0,0 +1 @@ +Support expiry of refresh tokens and expiry of the overall session when refresh tokens are in use. \ No newline at end of file diff --git a/synapse/config/registration.py b/synapse/config/registration.py index 61e569d41..5e2154806 100644 --- a/synapse/config/registration.py +++ b/synapse/config/registration.py @@ -113,14 +113,11 @@ class RegistrationConfig(Config): self.session_lifetime = session_lifetime # The `refreshable_access_token_lifetime` applies for tokens that can be renewed - # using a refresh token, as per MSC2918. If it is `None`, the refresh - # token mechanism is disabled. - # - # Since it is incompatible with the `session_lifetime` mechanism, it is set to - # `None` by default if a `session_lifetime` is set. + # using a refresh token, as per MSC2918. + # If it is `None`, the refresh token mechanism is disabled. refreshable_access_token_lifetime = config.get( "refreshable_access_token_lifetime", - "5m" if session_lifetime is None else None, + "5m", ) if refreshable_access_token_lifetime is not None: refreshable_access_token_lifetime = self.parse_duration( @@ -128,17 +125,10 @@ class RegistrationConfig(Config): ) self.refreshable_access_token_lifetime = refreshable_access_token_lifetime - if ( - session_lifetime is not None - and refreshable_access_token_lifetime is not None - ): - raise ConfigError( - "The refresh token mechanism is incompatible with the " - "`session_lifetime` option. Consider disabling the " - "`session_lifetime` option or disabling the refresh token " - "mechanism by removing the `refreshable_access_token_lifetime` " - "option." - ) + refresh_token_lifetime = config.get("refresh_token_lifetime") + if refresh_token_lifetime is not None: + refresh_token_lifetime = self.parse_duration(refresh_token_lifetime) + self.refresh_token_lifetime = refresh_token_lifetime # The fallback template used for authenticating using a registration token self.registration_token_template = self.read_template("registration_token.html") diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py index 4b66a9862..4d9c4e583 100644 --- a/synapse/handlers/auth.py +++ b/synapse/handlers/auth.py @@ -18,6 +18,7 @@ import time import unicodedata import urllib.parse from binascii import crc32 +from http import HTTPStatus from typing import ( TYPE_CHECKING, Any, @@ -756,53 +757,109 @@ class AuthHandler: async def refresh_token( self, refresh_token: str, - valid_until_ms: Optional[int], - ) -> Tuple[str, str]: + access_token_valid_until_ms: Optional[int], + refresh_token_valid_until_ms: Optional[int], + ) -> Tuple[str, str, Optional[int]]: """ Consumes a refresh token and generate both a new access token and a new refresh token from it. The consumed refresh token is considered invalid after the first use of the new access token or the new refresh token. + The lifetime of both the access token and refresh token will be capped so that they + do not exceed the session's ultimate expiry time, if applicable. + Args: refresh_token: The token to consume. - valid_until_ms: The expiration timestamp of the new access token. - + access_token_valid_until_ms: The expiration timestamp of the new access token. + None if the access token does not expire. + refresh_token_valid_until_ms: The expiration timestamp of the new refresh token. + None if the refresh token does not expire. Returns: - A tuple containing the new access token and refresh token + A tuple containing: + - the new access token + - the new refresh token + - the actual expiry time of the access token, which may be earlier than + `access_token_valid_until_ms`. """ # Verify the token signature first before looking up the token if not self._verify_refresh_token(refresh_token): - raise SynapseError(401, "invalid refresh token", Codes.UNKNOWN_TOKEN) + raise SynapseError( + HTTPStatus.UNAUTHORIZED, "invalid refresh token", Codes.UNKNOWN_TOKEN + ) existing_token = await self.store.lookup_refresh_token(refresh_token) if existing_token is None: - raise SynapseError(401, "refresh token does not exist", Codes.UNKNOWN_TOKEN) + raise SynapseError( + HTTPStatus.UNAUTHORIZED, + "refresh token does not exist", + Codes.UNKNOWN_TOKEN, + ) if ( existing_token.has_next_access_token_been_used or existing_token.has_next_refresh_token_been_refreshed ): raise SynapseError( - 403, "refresh token isn't valid anymore", Codes.FORBIDDEN + HTTPStatus.FORBIDDEN, + "refresh token isn't valid anymore", + Codes.FORBIDDEN, ) + now_ms = self._clock.time_msec() + + if existing_token.expiry_ts is not None and existing_token.expiry_ts < now_ms: + + raise SynapseError( + HTTPStatus.FORBIDDEN, + "The supplied refresh token has expired", + Codes.FORBIDDEN, + ) + + if existing_token.ultimate_session_expiry_ts is not None: + # This session has a bounded lifetime, even across refreshes. + + if access_token_valid_until_ms is not None: + access_token_valid_until_ms = min( + access_token_valid_until_ms, + existing_token.ultimate_session_expiry_ts, + ) + else: + access_token_valid_until_ms = existing_token.ultimate_session_expiry_ts + + if refresh_token_valid_until_ms is not None: + refresh_token_valid_until_ms = min( + refresh_token_valid_until_ms, + existing_token.ultimate_session_expiry_ts, + ) + else: + refresh_token_valid_until_ms = existing_token.ultimate_session_expiry_ts + if existing_token.ultimate_session_expiry_ts < now_ms: + raise SynapseError( + HTTPStatus.FORBIDDEN, + "The session has expired and can no longer be refreshed", + Codes.FORBIDDEN, + ) + ( new_refresh_token, new_refresh_token_id, ) = await self.create_refresh_token_for_user_id( - user_id=existing_token.user_id, device_id=existing_token.device_id + user_id=existing_token.user_id, + device_id=existing_token.device_id, + expiry_ts=refresh_token_valid_until_ms, + ultimate_session_expiry_ts=existing_token.ultimate_session_expiry_ts, ) access_token = await self.create_access_token_for_user_id( user_id=existing_token.user_id, device_id=existing_token.device_id, - valid_until_ms=valid_until_ms, + valid_until_ms=access_token_valid_until_ms, refresh_token_id=new_refresh_token_id, ) await self.store.replace_refresh_token( existing_token.token_id, new_refresh_token_id ) - return access_token, new_refresh_token + return access_token, new_refresh_token, access_token_valid_until_ms def _verify_refresh_token(self, token: str) -> bool: """ @@ -836,6 +893,8 @@ class AuthHandler: self, user_id: str, device_id: str, + expiry_ts: Optional[int], + ultimate_session_expiry_ts: Optional[int], ) -> Tuple[str, int]: """ Creates a new refresh token for the user with the given user ID. @@ -843,6 +902,13 @@ class AuthHandler: Args: user_id: canonical user ID device_id: the device ID to associate with the token. + expiry_ts (milliseconds since the epoch): Time after which the + refresh token cannot be used. + If None, the refresh token never expires until it has been used. + ultimate_session_expiry_ts (milliseconds since the epoch): + Time at which the session will end and can not be extended any + further. + If None, the session can be refreshed indefinitely. Returns: The newly created refresh token and its ID in the database @@ -852,6 +918,8 @@ class AuthHandler: user_id=user_id, token=refresh_token, device_id=device_id, + expiry_ts=expiry_ts, + ultimate_session_expiry_ts=ultimate_session_expiry_ts, ) return refresh_token, refresh_token_id diff --git a/synapse/handlers/register.py b/synapse/handlers/register.py index 448a36108..8136ae264 100644 --- a/synapse/handlers/register.py +++ b/synapse/handlers/register.py @@ -119,6 +119,7 @@ class RegistrationHandler: self.refreshable_access_token_lifetime = ( hs.config.registration.refreshable_access_token_lifetime ) + self.refresh_token_lifetime = hs.config.registration.refresh_token_lifetime init_counters_for_auth_provider("") @@ -793,13 +794,13 @@ class RegistrationHandler: class and RegisterDeviceReplicationServlet. """ assert not self.hs.config.worker.worker_app - valid_until_ms = None + access_token_expiry = None if self.session_lifetime is not None: if is_guest: raise Exception( "session_lifetime is not currently implemented for guest access" ) - valid_until_ms = self.clock.time_msec() + self.session_lifetime + access_token_expiry = self.clock.time_msec() + self.session_lifetime refresh_token = None refresh_token_id = None @@ -808,25 +809,52 @@ class RegistrationHandler: user_id, device_id, initial_display_name ) if is_guest: - assert valid_until_ms is None + assert access_token_expiry is None access_token = self.macaroon_gen.generate_guest_access_token(user_id) else: if should_issue_refresh_token: + now_ms = self.clock.time_msec() + + # Set the expiry time of the refreshable access token + access_token_expiry = now_ms + self.refreshable_access_token_lifetime + + # Set the refresh token expiry time (if configured) + refresh_token_expiry = None + if self.refresh_token_lifetime is not None: + refresh_token_expiry = now_ms + self.refresh_token_lifetime + + # Set an ultimate session expiry time (if configured) + ultimate_session_expiry_ts = None + if self.session_lifetime is not None: + ultimate_session_expiry_ts = now_ms + self.session_lifetime + + # Also ensure that the issued tokens don't outlive the + # session. + # (It would be weird to configure a homeserver with a shorter + # session lifetime than token lifetime, but may as well handle + # it.) + access_token_expiry = min( + access_token_expiry, ultimate_session_expiry_ts + ) + if refresh_token_expiry is not None: + refresh_token_expiry = min( + refresh_token_expiry, ultimate_session_expiry_ts + ) + ( refresh_token, refresh_token_id, ) = await self._auth_handler.create_refresh_token_for_user_id( user_id, device_id=registered_device_id, - ) - valid_until_ms = ( - self.clock.time_msec() + self.refreshable_access_token_lifetime + expiry_ts=refresh_token_expiry, + ultimate_session_expiry_ts=ultimate_session_expiry_ts, ) access_token = await self._auth_handler.create_access_token_for_user_id( user_id, device_id=registered_device_id, - valid_until_ms=valid_until_ms, + valid_until_ms=access_token_expiry, is_appservice_ghost=is_appservice_ghost, refresh_token_id=refresh_token_id, ) @@ -834,7 +862,7 @@ class RegistrationHandler: return { "device_id": registered_device_id, "access_token": access_token, - "valid_until_ms": valid_until_ms, + "valid_until_ms": access_token_expiry, "refresh_token": refresh_token, } diff --git a/synapse/rest/client/login.py b/synapse/rest/client/login.py index 67e03dca0..c982e5415 100644 --- a/synapse/rest/client/login.py +++ b/synapse/rest/client/login.py @@ -14,7 +14,17 @@ import logging import re -from typing import TYPE_CHECKING, Any, Awaitable, Callable, Dict, List, Optional, Tuple +from typing import ( + TYPE_CHECKING, + Any, + Awaitable, + Callable, + Dict, + List, + Optional, + Tuple, + Union, +) from typing_extensions import TypedDict @@ -458,6 +468,7 @@ class RefreshTokenServlet(RestServlet): self.refreshable_access_token_lifetime = ( hs.config.registration.refreshable_access_token_lifetime ) + self.refresh_token_lifetime = hs.config.registration.refresh_token_lifetime async def on_POST(self, request: SynapseRequest) -> Tuple[int, JsonDict]: refresh_submission = parse_json_object_from_request(request) @@ -467,22 +478,33 @@ class RefreshTokenServlet(RestServlet): if not isinstance(token, str): raise SynapseError(400, "Invalid param: refresh_token", Codes.INVALID_PARAM) - valid_until_ms = ( - self._clock.time_msec() + self.refreshable_access_token_lifetime - ) - access_token, refresh_token = await self._auth_handler.refresh_token( - token, valid_until_ms - ) - expires_in_ms = valid_until_ms - self._clock.time_msec() - return ( - 200, - { - "access_token": access_token, - "refresh_token": refresh_token, - "expires_in_ms": expires_in_ms, - }, + now = self._clock.time_msec() + access_valid_until_ms = None + if self.refreshable_access_token_lifetime is not None: + access_valid_until_ms = now + self.refreshable_access_token_lifetime + refresh_valid_until_ms = None + if self.refresh_token_lifetime is not None: + refresh_valid_until_ms = now + self.refresh_token_lifetime + + ( + access_token, + refresh_token, + actual_access_token_expiry, + ) = await self._auth_handler.refresh_token( + token, access_valid_until_ms, refresh_valid_until_ms ) + response: Dict[str, Union[str, int]] = { + "access_token": access_token, + "refresh_token": refresh_token, + } + + # expires_in_ms is only present if the token expires + if actual_access_token_expiry is not None: + response["expires_in_ms"] = actual_access_token_expiry - now + + return 200, response + class SsoRedirectServlet(RestServlet): PATTERNS = list(client_patterns("/login/(cas|sso)/redirect$", v1=True)) + [ diff --git a/synapse/storage/databases/main/registration.py b/synapse/storage/databases/main/registration.py index 0e8c16866..e1ddf0691 100644 --- a/synapse/storage/databases/main/registration.py +++ b/synapse/storage/databases/main/registration.py @@ -106,6 +106,15 @@ class RefreshTokenLookupResult: has_next_access_token_been_used: bool """True if the next access token was already used at least once.""" + expiry_ts: Optional[int] + """The time at which the refresh token expires and can not be used. + If None, the refresh token doesn't expire.""" + + ultimate_session_expiry_ts: Optional[int] + """The time at which the session comes to an end and can no longer be + refreshed. + If None, the session can be refreshed indefinitely.""" + class RegistrationWorkerStore(CacheInvalidationWorkerStore): def __init__( @@ -1626,8 +1635,10 @@ class RegistrationWorkerStore(CacheInvalidationWorkerStore): rt.user_id, rt.device_id, rt.next_token_id, - (nrt.next_token_id IS NOT NULL) has_next_refresh_token_been_refreshed, - at.used has_next_access_token_been_used + (nrt.next_token_id IS NOT NULL) AS has_next_refresh_token_been_refreshed, + at.used AS has_next_access_token_been_used, + rt.expiry_ts, + rt.ultimate_session_expiry_ts FROM refresh_tokens rt LEFT JOIN refresh_tokens nrt ON rt.next_token_id = nrt.id LEFT JOIN access_tokens at ON at.refresh_token_id = nrt.id @@ -1648,6 +1659,8 @@ class RegistrationWorkerStore(CacheInvalidationWorkerStore): has_next_refresh_token_been_refreshed=row[4], # This column is nullable, ensure it's a boolean has_next_access_token_been_used=(row[5] or False), + expiry_ts=row[6], + ultimate_session_expiry_ts=row[7], ) return await self.db_pool.runInteraction( @@ -1915,6 +1928,8 @@ class RegistrationStore(StatsStore, RegistrationBackgroundUpdateStore): user_id: str, token: str, device_id: Optional[str], + expiry_ts: Optional[int], + ultimate_session_expiry_ts: Optional[int], ) -> int: """Adds a refresh token for the given user. @@ -1922,6 +1937,13 @@ class RegistrationStore(StatsStore, RegistrationBackgroundUpdateStore): user_id: The user ID. token: The new access token to add. device_id: ID of the device to associate with the refresh token. + expiry_ts (milliseconds since the epoch): Time after which the + refresh token cannot be used. + If None, the refresh token never expires until it has been used. + ultimate_session_expiry_ts (milliseconds since the epoch): + Time at which the session will end and can not be extended any + further. + If None, the session can be refreshed indefinitely. Raises: StoreError if there was a problem adding this. Returns: @@ -1937,6 +1959,8 @@ class RegistrationStore(StatsStore, RegistrationBackgroundUpdateStore): "device_id": device_id, "token": token, "next_token_id": None, + "expiry_ts": expiry_ts, + "ultimate_session_expiry_ts": ultimate_session_expiry_ts, }, desc="add_refresh_token_to_user", ) diff --git a/synapse/storage/schema/main/delta/65/10_expirable_refresh_tokens.sql b/synapse/storage/schema/main/delta/65/10_expirable_refresh_tokens.sql new file mode 100644 index 000000000..bdc491c81 --- /dev/null +++ b/synapse/storage/schema/main/delta/65/10_expirable_refresh_tokens.sql @@ -0,0 +1,28 @@ +/* Copyright 2021 The Matrix.org Foundation C.I.C + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + + +ALTER TABLE refresh_tokens + -- We add an expiry_ts column (in milliseconds since the Epoch) to refresh tokens. + -- They may not be used after they have expired. + -- If null, then the refresh token's lifetime is unlimited. + ADD COLUMN expiry_ts BIGINT DEFAULT NULL; + +ALTER TABLE refresh_tokens + -- We also add an ultimate session expiry time (in milliseconds since the Epoch). + -- No matter how much the access and refresh tokens are refreshed, they cannot + -- be extended past this time. + -- If null, then the session length is unlimited. + ADD COLUMN ultimate_session_expiry_ts BIGINT DEFAULT NULL; diff --git a/tests/rest/client/test_auth.py b/tests/rest/client/test_auth.py index 855267143..8045b7f76 100644 --- a/tests/rest/client/test_auth.py +++ b/tests/rest/client/test_auth.py @@ -12,6 +12,7 @@ # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. +from http import HTTPStatus from typing import Optional, Union from twisted.internet.defer import succeed @@ -513,6 +514,16 @@ class RefreshAuthTests(unittest.HomeserverTestCase): self.user_pass = "pass" self.user = self.register_user("test", self.user_pass) + def use_refresh_token(self, refresh_token: str) -> FakeChannel: + """ + Helper that makes a request to use a refresh token. + """ + return self.make_request( + "POST", + "/_matrix/client/unstable/org.matrix.msc2918.refresh_token/refresh", + {"refresh_token": refresh_token}, + ) + def test_login_issue_refresh_token(self): """ A login response should include a refresh_token only if asked. @@ -599,7 +610,7 @@ class RefreshAuthTests(unittest.HomeserverTestCase): ) @override_config({"refreshable_access_token_lifetime": "1m"}) - def test_refresh_token_expiration(self): + def test_refreshable_access_token_expiration(self): """ The access token should have some time as specified in the config. """ @@ -623,6 +634,118 @@ class RefreshAuthTests(unittest.HomeserverTestCase): self.assertApproximates( refresh_response.json_body["expires_in_ms"], 60 * 1000, 100 ) + access_token = refresh_response.json_body["access_token"] + + # Advance 59 seconds in the future (just shy of 1 minute, the time of expiry) + self.reactor.advance(59.0) + # Check that our token is valid + self.assertEqual( + self.make_request( + "GET", "/_matrix/client/v3/account/whoami", access_token=access_token + ).code, + HTTPStatus.OK, + ) + + # Advance 2 more seconds (just past the time of expiry) + self.reactor.advance(2.0) + # Check that our token is invalid + self.assertEqual( + self.make_request( + "GET", "/_matrix/client/v3/account/whoami", access_token=access_token + ).code, + HTTPStatus.UNAUTHORIZED, + ) + + @override_config( + {"refreshable_access_token_lifetime": "1m", "refresh_token_lifetime": "2m"} + ) + def test_refresh_token_expiry(self): + """ + The refresh token can be configured to have a limited lifetime. + When that lifetime has ended, the refresh token can no longer be used to + refresh the session. + """ + + body = {"type": "m.login.password", "user": "test", "password": self.user_pass} + login_response = self.make_request( + "POST", + "/_matrix/client/r0/login?org.matrix.msc2918.refresh_token=true", + body, + ) + self.assertEqual(login_response.code, HTTPStatus.OK, login_response.result) + refresh_token1 = login_response.json_body["refresh_token"] + + # Advance 119 seconds in the future (just shy of 2 minutes) + self.reactor.advance(119.0) + + # Refresh our session. The refresh token should still JUST be valid right now. + # By doing so, we get a new access token and a new refresh token. + refresh_response = self.use_refresh_token(refresh_token1) + self.assertEqual(refresh_response.code, HTTPStatus.OK, refresh_response.result) + self.assertIn( + "refresh_token", + refresh_response.json_body, + "No new refresh token returned after refresh.", + ) + refresh_token2 = refresh_response.json_body["refresh_token"] + + # Advance 121 seconds in the future (just a bit more than 2 minutes) + self.reactor.advance(121.0) + + # Try to refresh our session, but instead notice that the refresh token is + # not valid (it just expired). + refresh_response = self.use_refresh_token(refresh_token2) + self.assertEqual( + refresh_response.code, HTTPStatus.FORBIDDEN, refresh_response.result + ) + + @override_config( + { + "refreshable_access_token_lifetime": "2m", + "refresh_token_lifetime": "2m", + "session_lifetime": "3m", + } + ) + def test_ultimate_session_expiry(self): + """ + The session can be configured to have an ultimate, limited lifetime. + """ + + body = {"type": "m.login.password", "user": "test", "password": self.user_pass} + login_response = self.make_request( + "POST", + "/_matrix/client/r0/login?org.matrix.msc2918.refresh_token=true", + body, + ) + self.assertEqual(login_response.code, 200, login_response.result) + refresh_token = login_response.json_body["refresh_token"] + + # Advance shy of 2 minutes into the future + self.reactor.advance(119.0) + + # Refresh our session. The refresh token should still be valid right now. + refresh_response = self.use_refresh_token(refresh_token) + self.assertEqual(refresh_response.code, 200, refresh_response.result) + self.assertIn( + "refresh_token", + refresh_response.json_body, + "No new refresh token returned after refresh.", + ) + # Notice that our access token lifetime has been diminished to match the + # session lifetime. + # 3 minutes - 119 seconds = 61 seconds. + self.assertEqual(refresh_response.json_body["expires_in_ms"], 61_000) + refresh_token = refresh_response.json_body["refresh_token"] + + # Advance 61 seconds into the future. Our session should have expired + # now, because we've had our 3 minutes. + self.reactor.advance(61.0) + + # Try to issue a new, refreshed, access token. + # This should fail because the refresh token's lifetime has also been + # diminished as our session expired. + refresh_response = self.use_refresh_token(refresh_token) + self.assertEqual(refresh_response.code, 403, refresh_response.result) def test_refresh_token_invalidation(self): """Refresh tokens are invalidated after first use of the next token.