Add support for MSC3823 - Account Suspension Part 2 (#17255)

9 files changed, 287 insertions, 0 deletions

diff --git a/changelog.d/17255.feature b/changelog.d/17255.feature
new file mode 100644
index 0000000000..4093de1146
--- /dev/null
+++ b/changelog.d/17255.feature
@@ -0,0 +1 @@
+Add support for [MSC823](https://github.com/matrix-org/matrix-spec-proposals/pull/3823) - Account suspension.
\ No newline at end of file
diff --git a/synapse/config/experimental.py b/synapse/config/experimental.py
index 23e96da6a3..1b72727b75 100644
--- a/synapse/config/experimental.py
+++ b/synapse/config/experimental.py
@@ -433,6 +433,10 @@ class ExperimentalConfig(Config):
                 ("experimental", "msc4108_delegation_endpoint"),
             )
 
+        self.msc3823_account_suspension = experimental.get(
+            "msc3823_account_suspension", False
+        )
+
         self.msc3916_authenticated_media_enabled = experimental.get(
             "msc3916_authenticated_media_enabled", False
         )
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 16d01efc67..5aa48230ec 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -642,6 +642,17 @@ class EventCreationHandler:
         """
         await self.auth_blocking.check_auth_blocking(requester=requester)
 
+        if event_dict["type"] == EventTypes.Message:
+            requester_suspended = await self.store.get_user_suspended_status(
+                requester.user.to_string()
+            )
+            if requester_suspended:
+                raise SynapseError(
+                    403,
+                    "Sending messages while account is suspended is not allowed.",
+                    Codes.USER_ACCOUNT_SUSPENDED,
+                )
+
         if event_dict["type"] == EventTypes.Create and event_dict["state_key"] == "":
             room_version_id = event_dict["content"]["room_version"]
             maybe_room_version_obj = KNOWN_ROOM_VERSIONS.get(room_version_id)
diff --git a/synapse/rest/admin/__init__.py b/synapse/rest/admin/__init__.py
index 6da1d79168..cdaee17451 100644
--- a/synapse/rest/admin/__init__.py
+++ b/synapse/rest/admin/__init__.py
@@ -101,6 +101,7 @@ from synapse.rest.admin.users import (
     ResetPasswordRestServlet,
     SearchUsersRestServlet,
     ShadowBanRestServlet,
+    SuspendAccountRestServlet,
     UserAdminServlet,
     UserByExternalId,
     UserByThreePid,
@@ -327,6 +328,8 @@ def register_servlets(hs: "HomeServer", http_server: HttpServer) -> None:
     BackgroundUpdateRestServlet(hs).register(http_server)
     BackgroundUpdateStartJobRestServlet(hs).register(http_server)
     ExperimentalFeaturesRestServlet(hs).register(http_server)
+    if hs.config.experimental.msc3823_account_suspension:
+        SuspendAccountRestServlet(hs).register(http_server)
 
 
 def register_servlets_for_client_rest_resource(
diff --git a/synapse/rest/admin/users.py b/synapse/rest/admin/users.py
index f7cb9e02cc..ad515bd5a3 100644
--- a/synapse/rest/admin/users.py
+++ b/synapse/rest/admin/users.py
@@ -27,11 +27,13 @@ from typing import TYPE_CHECKING, Dict, List, Optional, Tuple, Union
 
 import attr
 
+from synapse._pydantic_compat import HAS_PYDANTIC_V2
 from synapse.api.constants import Direction, UserTypes
 from synapse.api.errors import Codes, NotFoundError, SynapseError
 from synapse.http.servlet import (
     RestServlet,
     assert_params_in_dict,
+    parse_and_validate_json_object_from_request,
     parse_boolean,
     parse_enum,
     parse_integer,
@@ -49,10 +51,17 @@ from synapse.rest.client._base import client_patterns
 from synapse.storage.databases.main.registration import ExternalIDReuseException
 from synapse.storage.databases.main.stats import UserSortOrder
 from synapse.types import JsonDict, JsonMapping, UserID
+from synapse.types.rest import RequestBodyModel
 
 if TYPE_CHECKING:
     from synapse.server import HomeServer
 
+if TYPE_CHECKING or HAS_PYDANTIC_V2:
+    from pydantic.v1 import StrictBool
+else:
+    from pydantic import StrictBool
+
+
 logger = logging.getLogger(__name__)
 
 
@@ -732,6 +741,36 @@ class DeactivateAccountRestServlet(RestServlet):
         return HTTPStatus.OK, {"id_server_unbind_result": id_server_unbind_result}
 
 
+class SuspendAccountRestServlet(RestServlet):
+    PATTERNS = admin_patterns("/suspend/(?P<target_user_id>[^/]*)$")
+
+    def __init__(self, hs: "HomeServer"):
+        self.auth = hs.get_auth()
+        self.is_mine = hs.is_mine
+        self.store = hs.get_datastores().main
+
+    class PutBody(RequestBodyModel):
+        suspend: StrictBool
+
+    async def on_PUT(
+        self, request: SynapseRequest, target_user_id: str
+    ) -> Tuple[int, JsonDict]:
+        requester = await self.auth.get_user_by_req(request)
+        await assert_user_is_admin(self.auth, requester)
+
+        if not self.is_mine(UserID.from_string(target_user_id)):
+            raise SynapseError(HTTPStatus.BAD_REQUEST, "Can only suspend local users")
+
+        if not await self.store.get_user_by_id(target_user_id):
+            raise NotFoundError("User not found")
+
+        body = parse_and_validate_json_object_from_request(request, self.PutBody)
+        suspend = body.suspend
+        await self.store.set_user_suspended_status(target_user_id, suspend)
+
+        return HTTPStatus.OK, {f"user_{target_user_id}_suspended": suspend}
+
+
 class AccountValidityRenewServlet(RestServlet):
     PATTERNS = admin_patterns("/account_validity/validity$")
 
diff --git a/synapse/rest/client/profile.py b/synapse/rest/client/profile.py
index 0323f6afa1..c1a80c5c3d 100644
--- a/synapse/rest/client/profile.py
+++ b/synapse/rest/client/profile.py
@@ -108,6 +108,19 @@ class ProfileDisplaynameRestServlet(RestServlet):
 
         propagate = _read_propagate(self.hs, request)
 
+        requester_suspended = (
+            await self.hs.get_datastores().main.get_user_suspended_status(
+                requester.user.to_string()
+            )
+        )
+
+        if requester_suspended:
+            raise SynapseError(
+                403,
+                "Updating displayname while account is suspended is not allowed.",
+                Codes.USER_ACCOUNT_SUSPENDED,
+            )
+
         await self.profile_handler.set_displayname(
             user, requester, new_name, is_admin, propagate=propagate
         )
@@ -167,6 +180,19 @@ class ProfileAvatarURLRestServlet(RestServlet):
 
         propagate = _read_propagate(self.hs, request)
 
+        requester_suspended = (
+            await self.hs.get_datastores().main.get_user_suspended_status(
+                requester.user.to_string()
+            )
+        )
+
+        if requester_suspended:
+            raise SynapseError(
+                403,
+                "Updating avatar URL while account is suspended is not allowed.",
+                Codes.USER_ACCOUNT_SUSPENDED,
+            )
+
         await self.profile_handler.set_avatar_url(
             user, requester, new_avatar_url, is_admin, propagate=propagate
         )
diff --git a/synapse/rest/client/room.py b/synapse/rest/client/room.py
index bd65cf4b83..903c74f6d8 100644
--- a/synapse/rest/client/room.py
+++ b/synapse/rest/client/room.py
@@ -1120,6 +1120,20 @@ class RoomRedactEventRestServlet(TransactionRestServlet):
     ) -> Tuple[int, JsonDict]:
         content = parse_json_object_from_request(request)
 
+        requester_suspended = await self._store.get_user_suspended_status(
+            requester.user.to_string()
+        )
+
+        if requester_suspended:
+            event = await self._store.get_event(event_id, allow_none=True)
+            if event:
+                if event.sender != requester.user.to_string():
+                    raise SynapseError(
+                        403,
+                        "You can only redact your own events while account is suspended.",
+                        Codes.USER_ACCOUNT_SUSPENDED,
+                    )
+
         # Ensure the redacts property in the content matches the one provided in
         # the URL.
         room_version = await self._store.get_room_version(room_id)
diff --git a/tests/rest/admin/test_user.py b/tests/rest/admin/test_user.py
index c5da1e9686..16bb4349f5 100644
--- a/tests/rest/admin/test_user.py
+++ b/tests/rest/admin/test_user.py
@@ -37,6 +37,7 @@ from synapse.api.constants import ApprovalNoticeMedium, LoginType, UserTypes
 from synapse.api.errors import Codes, HttpResponseException, ResourceLimitError
 from synapse.api.room_versions import RoomVersions
 from synapse.media.filepath import MediaFilePaths
+from synapse.rest import admin
 from synapse.rest.client import (
     devices,
     login,
@@ -5005,3 +5006,86 @@ class AllowCrossSigningReplacementTestCase(unittest.HomeserverTestCase):
         )
         assert timestamp is not None
         self.assertGreater(timestamp, self.clock.time_msec())
+
+
+class UserSuspensionTestCase(unittest.HomeserverTestCase):
+    servlets = [
+        synapse.rest.admin.register_servlets,
+        login.register_servlets,
+        admin.register_servlets,
+    ]
+
+    def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
+        self.admin = self.register_user("thomas", "hackme", True)
+        self.admin_tok = self.login("thomas", "hackme")
+
+        self.bad_user = self.register_user("teresa", "hackme")
+        self.bad_user_tok = self.login("teresa", "hackme")
+
+        self.store = hs.get_datastores().main
+
+    @override_config({"experimental_features": {"msc3823_account_suspension": True}})
+    def test_suspend_user(self) -> None:
+        # test that suspending user works
+        channel = self.make_request(
+            "PUT",
+            f"/_synapse/admin/v1/suspend/{self.bad_user}",
+            {"suspend": True},
+            access_token=self.admin_tok,
+        )
+        self.assertEqual(channel.code, 200)
+        self.assertEqual(channel.json_body, {f"user_{self.bad_user}_suspended": True})
+
+        res = self.get_success(self.store.get_user_suspended_status(self.bad_user))
+        self.assertEqual(True, res)
+
+        # test that un-suspending user works
+        channel2 = self.make_request(
+            "PUT",
+            f"/_synapse/admin/v1/suspend/{self.bad_user}",
+            {"suspend": False},
+            access_token=self.admin_tok,
+        )
+        self.assertEqual(channel2.code, 200)
+        self.assertEqual(channel2.json_body, {f"user_{self.bad_user}_suspended": False})
+
+        res2 = self.get_success(self.store.get_user_suspended_status(self.bad_user))
+        self.assertEqual(False, res2)
+
+        # test that trying to un-suspend user who isn't suspended doesn't cause problems
+        channel3 = self.make_request(
+            "PUT",
+            f"/_synapse/admin/v1/suspend/{self.bad_user}",
+            {"suspend": False},
+            access_token=self.admin_tok,
+        )
+        self.assertEqual(channel3.code, 200)
+        self.assertEqual(channel3.json_body, {f"user_{self.bad_user}_suspended": False})
+
+        res3 = self.get_success(self.store.get_user_suspended_status(self.bad_user))
+        self.assertEqual(False, res3)
+
+        # test that trying to suspend user who is already suspended doesn't cause problems
+        channel4 = self.make_request(
+            "PUT",
+            f"/_synapse/admin/v1/suspend/{self.bad_user}",
+            {"suspend": True},
+            access_token=self.admin_tok,
+        )
+        self.assertEqual(channel4.code, 200)
+        self.assertEqual(channel4.json_body, {f"user_{self.bad_user}_suspended": True})
+
+        res4 = self.get_success(self.store.get_user_suspended_status(self.bad_user))
+        self.assertEqual(True, res4)
+
+        channel5 = self.make_request(
+            "PUT",
+            f"/_synapse/admin/v1/suspend/{self.bad_user}",
+            {"suspend": True},
+            access_token=self.admin_tok,
+        )
+        self.assertEqual(channel5.code, 200)
+        self.assertEqual(channel5.json_body, {f"user_{self.bad_user}_suspended": True})
+
+        res5 = self.get_success(self.store.get_user_suspended_status(self.bad_user))
+        self.assertEqual(True, res5)
diff --git a/tests/rest/client/test_rooms.py b/tests/rest/client/test_rooms.py
index d398cead1c..c559dfda83 100644
--- a/tests/rest/client/test_rooms.py
+++ b/tests/rest/client/test_rooms.py
@@ -3819,3 +3819,108 @@ class TimestampLookupTestCase(unittest.HomeserverTestCase):
 
         # Make sure the outlier event is not returned
         self.assertNotEqual(channel.json_body["event_id"], outlier_event.event_id)
+
+
+class UserSuspensionTests(unittest.HomeserverTestCase):
+    servlets = [
+        admin.register_servlets,
+        login.register_servlets,
+        room.register_servlets,
+        profile.register_servlets,
+    ]
+
+    def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
+        self.user1 = self.register_user("thomas", "hackme")
+        self.tok1 = self.login("thomas", "hackme")
+
+        self.user2 = self.register_user("teresa", "hackme")
+        self.tok2 = self.login("teresa", "hackme")
+
+        self.room1 = self.helper.create_room_as(room_creator=self.user1, tok=self.tok1)
+        self.store = hs.get_datastores().main
+
+    def test_suspended_user_cannot_send_message_to_room(self) -> None:
+        # set the user as suspended
+        self.get_success(self.store.set_user_suspended_status(self.user1, True))
+
+        channel = self.make_request(
+            "PUT",
+            f"/rooms/{self.room1}/send/m.room.message/1",
+            access_token=self.tok1,
+            content={"body": "hello", "msgtype": "m.text"},
+        )
+        self.assertEqual(
+            channel.json_body["errcode"], "ORG.MATRIX.MSC3823.USER_ACCOUNT_SUSPENDED"
+        )
+
+    def test_suspended_user_cannot_change_profile_data(self) -> None:
+        # set the user as suspended
+        self.get_success(self.store.set_user_suspended_status(self.user1, True))
+
+        channel = self.make_request(
+            "PUT",
+            f"/_matrix/client/v3/profile/{self.user1}/avatar_url",
+            access_token=self.tok1,
+            content={"avatar_url": "mxc://matrix.org/wefh34uihSDRGhw34"},
+            shorthand=False,
+        )
+        self.assertEqual(
+            channel.json_body["errcode"], "ORG.MATRIX.MSC3823.USER_ACCOUNT_SUSPENDED"
+        )
+
+        channel2 = self.make_request(
+            "PUT",
+            f"/_matrix/client/v3/profile/{self.user1}/displayname",
+            access_token=self.tok1,
+            content={"displayname": "something offensive"},
+            shorthand=False,
+        )
+        self.assertEqual(
+            channel2.json_body["errcode"], "ORG.MATRIX.MSC3823.USER_ACCOUNT_SUSPENDED"
+        )
+
+    def test_suspended_user_cannot_redact_messages_other_than_their_own(self) -> None:
+        # first user sends message
+        self.make_request("POST", f"/rooms/{self.room1}/join", access_token=self.tok2)
+        res = self.helper.send_event(
+            self.room1,
+            "m.room.message",
+            {"body": "hello", "msgtype": "m.text"},
+            tok=self.tok2,
+        )
+        event_id = res["event_id"]
+
+        # second user sends message
+        self.make_request("POST", f"/rooms/{self.room1}/join", access_token=self.tok1)
+        res2 = self.helper.send_event(
+            self.room1,
+            "m.room.message",
+            {"body": "bad_message", "msgtype": "m.text"},
+            tok=self.tok1,
+        )
+        event_id2 = res2["event_id"]
+
+        # set the second user as suspended
+        self.get_success(self.store.set_user_suspended_status(self.user1, True))
+
+        # second user can't redact first user's message
+        channel = self.make_request(
+            "PUT",
+            f"/_matrix/client/v3/rooms/{self.room1}/redact/{event_id}/1",
+            access_token=self.tok1,
+            content={"reason": "bogus"},
+            shorthand=False,
+        )
+        self.assertEqual(
+            channel.json_body["errcode"], "ORG.MATRIX.MSC3823.USER_ACCOUNT_SUSPENDED"
+        )
+
+        # but can redact their own
+        channel = self.make_request(
+            "PUT",
+            f"/_matrix/client/v3/rooms/{self.room1}/redact/{event_id2}/1",
+            access_token=self.tok1,
+            content={"reason": "bogus"},
+            shorthand=False,
+        )
+        self.assertEqual(channel.code, 200)