Merge pull request #3630 from matrix-org/neilj/mau_sign_in_log_in_limits

Initial impl of capping MAU

11 files changed, 275 insertions, 16 deletions

diff --git a/changelog.d/3630.feature b/changelog.d/3630.feature
new file mode 100644
index 0000000000..8007a04840
--- /dev/null
+++ b/changelog.d/3630.feature
@@ -0,0 +1 @@
+Add ability to limit number of monthly active users on the server
diff --git a/synapse/api/errors.py b/synapse/api/errors.py
index 6074df292f..14f5540280 100644
--- a/synapse/api/errors.py
+++ b/synapse/api/errors.py
@@ -55,6 +55,7 @@ class Codes(object):
     SERVER_NOT_TRUSTED = "M_SERVER_NOT_TRUSTED"
     CONSENT_NOT_GIVEN = "M_CONSENT_NOT_GIVEN"
     CANNOT_LEAVE_SERVER_NOTICE_ROOM = "M_CANNOT_LEAVE_SERVER_NOTICE_ROOM"
+    MAU_LIMIT_EXCEEDED = "M_MAU_LIMIT_EXCEEDED"
 
 
 class CodeMessageException(RuntimeError):
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index 57b815d777..fba51c26e8 100755
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -20,6 +20,8 @@ import sys
 
 from six import iteritems
 
+from prometheus_client import Gauge
+
 from twisted.application import service
 from twisted.internet import defer, reactor
 from twisted.web.resource import EncodingResourceWrapper, NoResource
@@ -300,6 +302,11 @@ class SynapseHomeServer(HomeServer):
             quit_with_error(e.message)
 
 
+# Gauges to expose monthly active user control metrics
+current_mau_gauge = Gauge("synapse_admin_current_mau", "Current MAU")
+max_mau_value_gauge = Gauge("synapse_admin_max_mau_value", "MAU Limit")
+
+
 def setup(config_options):
     """
     Args:
@@ -512,6 +519,18 @@ def run(hs):
     # table will decrease
     clock.looping_call(generate_user_daily_visit_stats, 5 * 60 * 1000)
 
+    @defer.inlineCallbacks
+    def generate_monthly_active_users():
+        count = 0
+        if hs.config.limit_usage_by_mau:
+            count = yield hs.get_datastore().count_monthly_users()
+        current_mau_gauge.set(float(count))
+        max_mau_value_gauge.set(float(hs.config.max_mau_value))
+
+    generate_monthly_active_users()
+    if hs.config.limit_usage_by_mau:
+        clock.looping_call(generate_monthly_active_users, 5 * 60 * 1000)
+
     if hs.config.report_stats:
         logger.info("Scheduling stats reporting for 3 hour intervals")
         clock.looping_call(start_phone_stats_home, 3 * 60 * 60 * 1000)
diff --git a/synapse/config/server.py b/synapse/config/server.py
index 18102656b0..a8014e9c50 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -67,6 +67,14 @@ class ServerConfig(Config):
             "block_non_admin_invites", False,
         )
 
+        # Options to control access by tracking MAU
+        self.limit_usage_by_mau = config.get("limit_usage_by_mau", False)
+        if self.limit_usage_by_mau:
+            self.max_mau_value = config.get(
+                "max_mau_value", 0,
+            )
+        else:
+            self.max_mau_value = 0
         # FIXME: federation_domain_whitelist needs sytests
         self.federation_domain_whitelist = None
         federation_domain_whitelist = config.get(
diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index 5d03bfa5f7..184eef09d0 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -520,6 +520,7 @@ class AuthHandler(BaseHandler):
         """
         logger.info("Logging in user %s on device %s", user_id, device_id)
         access_token = yield self.issue_access_token(user_id, device_id)
+        yield self._check_mau_limits()
 
         # the device *should* have been registered before we got here; however,
         # it's possible we raced against a DELETE operation. The thing we
@@ -731,15 +732,18 @@ class AuthHandler(BaseHandler):
                                                   device_id)
         defer.returnValue(access_token)
 
+    @defer.inlineCallbacks
     def validate_short_term_login_token_and_get_user_id(self, login_token):
+        yield self._check_mau_limits()
         auth_api = self.hs.get_auth()
+        user_id = None
         try:
             macaroon = pymacaroons.Macaroon.deserialize(login_token)
             user_id = auth_api.get_user_id_from_macaroon(macaroon)
             auth_api.validate_macaroon(macaroon, "login", True, user_id)
-            return user_id
         except Exception:
             raise AuthError(403, "Invalid token", errcode=Codes.FORBIDDEN)
+        defer.returnValue(user_id)
 
     @defer.inlineCallbacks
     def delete_access_token(self, access_token):
@@ -903,6 +907,19 @@ class AuthHandler(BaseHandler):
         else:
             return defer.succeed(False)
 
+    @defer.inlineCallbacks
+    def _check_mau_limits(self):
+        """
+        Ensure that if mau blocking is enabled that invalid users cannot
+        log in.
+        """
+        if self.hs.config.limit_usage_by_mau is True:
+            current_mau = yield self.store.count_monthly_users()
+            if current_mau >= self.hs.config.max_mau_value:
+                raise AuthError(
+                    403, "MAU Limit Exceeded", errcode=Codes.MAU_LIMIT_EXCEEDED
+                )
+
 
 @attr.s
 class MacaroonGenerator(object):
diff --git a/synapse/handlers/register.py b/synapse/handlers/register.py
index 234f8e8019..289704b241 100644
--- a/synapse/handlers/register.py
+++ b/synapse/handlers/register.py
@@ -45,7 +45,7 @@ class RegistrationHandler(BaseHandler):
             hs (synapse.server.HomeServer):
         """
         super(RegistrationHandler, self).__init__(hs)
-
+        self.hs = hs
         self.auth = hs.get_auth()
         self._auth_handler = hs.get_auth_handler()
         self.profile_handler = hs.get_profile_handler()
@@ -144,6 +144,7 @@ class RegistrationHandler(BaseHandler):
         Raises:
             RegistrationError if there was a problem registering.
         """
+        yield self._check_mau_limits()
         password_hash = None
         if password:
             password_hash = yield self.auth_handler().hash(password)
@@ -288,6 +289,7 @@ class RegistrationHandler(BaseHandler):
                 400,
                 "User ID can only contain characters a-z, 0-9, or '=_-./'",
             )
+        yield self._check_mau_limits()
         user = UserID(localpart, self.hs.hostname)
         user_id = user.to_string()
 
@@ -437,7 +439,7 @@ class RegistrationHandler(BaseHandler):
         """
         if localpart is None:
             raise SynapseError(400, "Request must include user id")
-
+        yield self._check_mau_limits()
         need_register = True
 
         try:
@@ -531,3 +533,16 @@ class RegistrationHandler(BaseHandler):
             remote_room_hosts=remote_room_hosts,
             action="join",
         )
+
+    @defer.inlineCallbacks
+    def _check_mau_limits(self):
+        """
+        Do not accept registrations if monthly active user limits exceeded
+         and limiting is enabled
+        """
+        if self.hs.config.limit_usage_by_mau is True:
+            current_mau = yield self.store.count_monthly_users()
+            if current_mau >= self.hs.config.max_mau_value:
+                raise RegistrationError(
+                    403, "MAU Limit Exceeded", Codes.MAU_LIMIT_EXCEEDED
+                )
diff --git a/synapse/storage/__init__.py b/synapse/storage/__init__.py
index 3bd63cd195..134e4a80f1 100644
--- a/synapse/storage/__init__.py
+++ b/synapse/storage/__init__.py
@@ -94,6 +94,7 @@ class DataStore(RoomMemberStore, RoomStore,
         self._clock = hs.get_clock()
         self.database_engine = hs.database_engine
 
+        self.db_conn = db_conn
         self._stream_id_gen = StreamIdGenerator(
             db_conn, "events", "stream_ordering",
             extra_tables=[("local_invites", "stream_id")]
@@ -266,6 +267,31 @@ class DataStore(RoomMemberStore, RoomStore,
 
         return self.runInteraction("count_users", _count_users)
 
+    def count_monthly_users(self):
+        """Counts the number of users who used this homeserver in the last 30 days
+
+        This method should be refactored with count_daily_users - the only
+        reason not to is waiting on definition of mau
+
+        Returns:
+            Defered[int]
+        """
+        def _count_monthly_users(txn):
+            thirty_days_ago = int(self._clock.time_msec()) - (1000 * 60 * 60 * 24 * 30)
+            sql = """
+                SELECT COALESCE(count(*), 0) FROM (
+                    SELECT user_id FROM user_ips
+                    WHERE last_seen > ?
+                    GROUP BY user_id
+                ) u
+            """
+
+            txn.execute(sql, (thirty_days_ago,))
+            count, = txn.fetchone()
+            return count
+
+        return self.runInteraction("count_monthly_users", _count_monthly_users)
+
     def count_r30_users(self):
         """
         Counts the number of 30 day retained users, defined as:-
diff --git a/synapse/storage/schema/delta/50/make_event_content_nullable.py b/synapse/storage/schema/delta/50/make_event_content_nullable.py
index 7d27342e39..6dd467b6c5 100644
--- a/synapse/storage/schema/delta/50/make_event_content_nullable.py
+++ b/synapse/storage/schema/delta/50/make_event_content_nullable.py
@@ -88,5 +88,5 @@ def run_upgrade(cur, database_engine, *args, **kwargs):
         "UPDATE sqlite_master SET sql=? WHERE tbl_name='events' AND type='table'",
         (sql, ),
     )
-    cur.execute("PRAGMA schema_version=%i" % (oldver+1,))
+    cur.execute("PRAGMA schema_version=%i" % (oldver + 1,))
     cur.execute("PRAGMA writable_schema=OFF")
diff --git a/tests/handlers/test_auth.py b/tests/handlers/test_auth.py
index 2e5e8e4dec..55eab9e9cf 100644
--- a/tests/handlers/test_auth.py
+++ b/tests/handlers/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 mock import Mock
 
 import pymacaroons
 
@@ -19,6 +20,7 @@ from twisted.internet import defer
 
 import synapse
 import synapse.api.errors
+from synapse.api.errors import AuthError
 from synapse.handlers.auth import AuthHandler
 
 from tests import unittest
@@ -37,6 +39,10 @@ class AuthTestCase(unittest.TestCase):
         self.hs.handlers = AuthHandlers(self.hs)
         self.auth_handler = self.hs.handlers.auth_handler
         self.macaroon_generator = self.hs.get_macaroon_generator()
+        # MAU tests
+        self.hs.config.max_mau_value = 50
+        self.small_number_of_users = 1
+        self.large_number_of_users = 100
 
     def test_token_is_a_macaroon(self):
         token = self.macaroon_generator.generate_access_token("some_user")
@@ -71,38 +77,37 @@ class AuthTestCase(unittest.TestCase):
         v.satisfy_general(verify_nonce)
         v.verify(macaroon, self.hs.config.macaroon_secret_key)
 
+    @defer.inlineCallbacks
     def test_short_term_login_token_gives_user_id(self):
         self.hs.clock.now = 1000
 
         token = self.macaroon_generator.generate_short_term_login_token(
             "a_user", 5000
         )
-
-        self.assertEqual(
-            "a_user",
-            self.auth_handler.validate_short_term_login_token_and_get_user_id(
-                token
-            )
+        user_id = yield self.auth_handler.validate_short_term_login_token_and_get_user_id(
+            token
         )
+        self.assertEqual("a_user", user_id)
 
         # when we advance the clock, the token should be rejected
         self.hs.clock.now = 6000
         with self.assertRaises(synapse.api.errors.AuthError):
-            self.auth_handler.validate_short_term_login_token_and_get_user_id(
+            yield self.auth_handler.validate_short_term_login_token_and_get_user_id(
                 token
             )
 
+    @defer.inlineCallbacks
     def test_short_term_login_token_cannot_replace_user_id(self):
         token = self.macaroon_generator.generate_short_term_login_token(
             "a_user", 5000
         )
         macaroon = pymacaroons.Macaroon.deserialize(token)
 
+        user_id = yield self.auth_handler.validate_short_term_login_token_and_get_user_id(
+            macaroon.serialize()
+        )
         self.assertEqual(
-            "a_user",
-            self.auth_handler.validate_short_term_login_token_and_get_user_id(
-                macaroon.serialize()
-            )
+            "a_user", user_id
         )
 
         # add another "user_id" caveat, which might allow us to override the
@@ -110,6 +115,57 @@ class AuthTestCase(unittest.TestCase):
         macaroon.add_first_party_caveat("user_id = b_user")
 
         with self.assertRaises(synapse.api.errors.AuthError):
-            self.auth_handler.validate_short_term_login_token_and_get_user_id(
+            yield self.auth_handler.validate_short_term_login_token_and_get_user_id(
                 macaroon.serialize()
             )
+
+    @defer.inlineCallbacks
+    def test_mau_limits_disabled(self):
+        self.hs.config.limit_usage_by_mau = False
+        # Ensure does not throw exception
+        yield self.auth_handler.get_access_token_for_user_id('user_a')
+
+        yield self.auth_handler.validate_short_term_login_token_and_get_user_id(
+            self._get_macaroon().serialize()
+        )
+
+    @defer.inlineCallbacks
+    def test_mau_limits_exceeded(self):
+        self.hs.config.limit_usage_by_mau = True
+        self.hs.get_datastore().count_monthly_users = Mock(
+            return_value=defer.succeed(self.large_number_of_users)
+        )
+
+        with self.assertRaises(AuthError):
+            yield self.auth_handler.get_access_token_for_user_id('user_a')
+
+        self.hs.get_datastore().count_monthly_users = Mock(
+            return_value=defer.succeed(self.large_number_of_users)
+        )
+        with self.assertRaises(AuthError):
+            yield self.auth_handler.validate_short_term_login_token_and_get_user_id(
+                self._get_macaroon().serialize()
+            )
+
+    @defer.inlineCallbacks
+    def test_mau_limits_not_exceeded(self):
+        self.hs.config.limit_usage_by_mau = True
+
+        self.hs.get_datastore().count_monthly_users = Mock(
+            return_value=defer.succeed(self.small_number_of_users)
+        )
+        # Ensure does not raise exception
+        yield self.auth_handler.get_access_token_for_user_id('user_a')
+
+        self.hs.get_datastore().count_monthly_users = Mock(
+            return_value=defer.succeed(self.small_number_of_users)
+        )
+        yield self.auth_handler.validate_short_term_login_token_and_get_user_id(
+            self._get_macaroon().serialize()
+        )
+
+    def _get_macaroon(self):
+        token = self.macaroon_generator.generate_short_term_login_token(
+            "user_a", 5000
+        )
+        return pymacaroons.Macaroon.deserialize(token)
diff --git a/tests/handlers/test_register.py b/tests/handlers/test_register.py
index 025fa1be81..0937d71cf6 100644
--- a/tests/handlers/test_register.py
+++ b/tests/handlers/test_register.py
@@ -17,6 +17,7 @@ from mock import Mock
 
 from twisted.internet import defer
 
+from synapse.api.errors import RegistrationError
 from synapse.handlers.register import RegistrationHandler
 from synapse.types import UserID, create_requester
 
@@ -77,3 +78,53 @@ class RegistrationTestCase(unittest.TestCase):
             requester, local_part, display_name)
         self.assertEquals(result_user_id, user_id)
         self.assertEquals(result_token, 'secret')
+
+    @defer.inlineCallbacks
+    def test_cannot_register_when_mau_limits_exceeded(self):
+        local_part = "someone"
+        display_name = "someone"
+        requester = create_requester("@as:test")
+        store = self.hs.get_datastore()
+        self.hs.config.limit_usage_by_mau = False
+        self.hs.config.max_mau_value = 50
+        lots_of_users = 100
+        small_number_users = 1
+
+        store.count_monthly_users = Mock(return_value=defer.succeed(lots_of_users))
+
+        # Ensure does not throw exception
+        yield self.handler.get_or_create_user(requester, 'a', display_name)
+
+        self.hs.config.limit_usage_by_mau = True
+
+        with self.assertRaises(RegistrationError):
+            yield self.handler.get_or_create_user(requester, 'b', display_name)
+
+        store.count_monthly_users = Mock(return_value=defer.succeed(small_number_users))
+
+        self._macaroon_mock_generator("another_secret")
+
+        # Ensure does not throw exception
+        yield self.handler.get_or_create_user("@neil:matrix.org", 'c', "Neil")
+
+        self._macaroon_mock_generator("another another secret")
+        store.count_monthly_users = Mock(return_value=defer.succeed(lots_of_users))
+
+        with self.assertRaises(RegistrationError):
+            yield self.handler.register(localpart=local_part)
+
+        self._macaroon_mock_generator("another another secret")
+        store.count_monthly_users = Mock(return_value=defer.succeed(lots_of_users))
+
+        with self.assertRaises(RegistrationError):
+            yield self.handler.register_saml2(local_part)
+
+    def _macaroon_mock_generator(self, secret):
+        """
+        Reset macaroon generator in the case where the test creates multiple users
+        """
+        macaroon_generator = Mock(
+            generate_access_token=Mock(return_value=secret))
+        self.hs.get_macaroon_generator = Mock(return_value=macaroon_generator)
+        self.hs.handlers = RegistrationHandlers(self.hs)
+        self.handler = self.hs.get_handlers().registration_handler
diff --git a/tests/storage/test__init__.py b/tests/storage/test__init__.py
new file mode 100644
index 0000000000..f19cb1265c
--- /dev/null
+++ b/tests/storage/test__init__.py
@@ -0,0 +1,65 @@
+# -*- coding: utf-8 -*-
+# Copyright 2018 New Vector Ltd
+#
+# 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.
+
+from twisted.internet import defer
+
+import tests.utils
+
+
+class InitTestCase(tests.unittest.TestCase):
+    def __init__(self, *args, **kwargs):
+        super(InitTestCase, self).__init__(*args, **kwargs)
+        self.store = None  # type: synapse.storage.DataStore
+
+    @defer.inlineCallbacks
+    def setUp(self):
+        hs = yield tests.utils.setup_test_homeserver()
+
+        hs.config.max_mau_value = 50
+        hs.config.limit_usage_by_mau = True
+        self.store = hs.get_datastore()
+        self.clock = hs.get_clock()
+
+    @defer.inlineCallbacks
+    def test_count_monthly_users(self):
+        count = yield self.store.count_monthly_users()
+        self.assertEqual(0, count)
+
+        yield self._insert_user_ips("@user:server1")
+        yield self._insert_user_ips("@user:server2")
+
+        count = yield self.store.count_monthly_users()
+        self.assertEqual(2, count)
+
+    @defer.inlineCallbacks
+    def _insert_user_ips(self, user):
+        """
+        Helper function to populate user_ips without using batch insertion infra
+        args:
+            user (str):  specify username i.e. @user:server.com
+        """
+        yield self.store._simple_upsert(
+            table="user_ips",
+            keyvalues={
+                "user_id": user,
+                "access_token": "access_token",
+                "ip": "ip",
+                "user_agent": "user_agent",
+                "device_id": "device_id",
+            },
+            values={
+                "last_seen": self.clock.time_msec(),
+            }
+        )