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Allow denying or shadow banning registrations via the spam checker (#8034)

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Patrick Cloke 2020-08-20 15:42:58 -04:00 committed by GitHub
parent e259d63f73
commit 3f91638da6
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14 changed files with 258 additions and 18 deletions
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1
changelog.d/8034.feature Normal file
View file

@ -0,0 +1 @@
Add support for shadow-banning users (ignoring any message send requests).

35
synapse/events/spamcheck.py
View file

@ -15,9 +15,10 @@
# limitations under the License.
import inspect
from typing import Any, Dict, List
from typing import Any, Dict, List, Optional, Tuple
from synapse.spam_checker_api import SpamCheckerApi
from synapse.spam_checker_api import RegistrationBehaviour, SpamCheckerApi
from synapse.types import Collection
MYPY = False
if MYPY:
@ -160,3 +161,33 @@ class SpamChecker(object):
return True
return False
def check_registration_for_spam(
self,
email_threepid: Optional[dict],
username: Optional[str],
request_info: Collection[Tuple[str, str]],
) -> RegistrationBehaviour:
"""Checks if we should allow the given registration request.
Args:
email_threepid: The email threepid used for registering, if any
username: The request user name, if any
request_info: List of tuples of user agent and IP that
were used during the registration process.
Returns:
Enum for how the request should be handled
"""
for spam_checker in self.spam_checkers:
# For backwards compatibility, only run if the method exists on the
# spam checker
checker = getattr(spam_checker, "check_registration_for_spam", None)
if checker:
behaviour = checker(email_threepid, username, request_info)
assert isinstance(behaviour, RegistrationBehaviour)
if behaviour != RegistrationBehaviour.ALLOW:
return behaviour
return RegistrationBehaviour.ALLOW

8
synapse/handlers/auth.py
View file

@ -364,6 +364,14 @@ class AuthHandler(BaseHandler):
# authentication flow.
await self.store.set_ui_auth_clientdict(sid, clientdict)
user_agent = request.requestHeaders.getRawHeaders(b"User-Agent", default=[b""])[
0
].decode("ascii", "surrogateescape")
await self.store.add_user_agent_ip_to_ui_auth_session(
session.session_id, user_agent, clientip
)
if not authdict:
raise InteractiveAuthIncompleteError(
session.session_id, self._auth_dict_for_flows(flows, session.session_id)

11
synapse/handlers/cas_handler.py
View file

@ -35,6 +35,7 @@ class CasHandler:
"""
def __init__(self, hs):
self.hs = hs
self._hostname = hs.hostname
self._auth_handler = hs.get_auth_handler()
self._registration_handler = hs.get_registration_handler()
@ -210,8 +211,16 @@ class CasHandler:
else:
if not registered_user_id:
# Pull out the user-agent and IP from the request.
user_agent = request.requestHeaders.getRawHeaders(
b"User-Agent", default=[b""]
)[0].decode("ascii", "surrogateescape")
ip_address = self.hs.get_ip_from_request(request)
registered_user_id = await self._registration_handler.register_user(
localpart=localpart, default_display_name=user_display_name
localpart=localpart,
default_display_name=user_display_name,
user_agent_ips=(user_agent, ip_address),
)
await self._auth_handler.complete_sso_login(

21
synapse/handlers/oidc_handler.py
View file

@ -93,6 +93,7 @@ class OidcHandler:
"""
def __init__(self, hs: "HomeServer"):
self.hs = hs
self._callback_url = hs.config.oidc_callback_url # type: str
self._scopes = hs.config.oidc_scopes # type: List[str]
self._client_auth = ClientAuth(
@ -689,9 +690,17 @@ class OidcHandler:
self._render_error(request, "invalid_token", str(e))
return
# Pull out the user-agent and IP from the request.
user_agent = request.requestHeaders.getRawHeaders(b"User-Agent", default=[b""])[
0
].decode("ascii", "surrogateescape")
ip_address = self.hs.get_ip_from_request(request)
# Call the mapper to register/login the user
try:
user_id = await self._map_userinfo_to_user(userinfo, token)
user_id = await self._map_userinfo_to_user(
userinfo, token, user_agent, ip_address
)
except MappingException as e:
logger.exception("Could not map user")
self._render_error(request, "mapping_error", str(e))
@ -828,7 +837,9 @@ class OidcHandler:
now = self._clock.time_msec()
return now < expiry
async def _map_userinfo_to_user(self, userinfo: UserInfo, token: Token) -> str:
async def _map_userinfo_to_user(
self, userinfo: UserInfo, token: Token, user_agent: str, ip_address: str
) -> str:
"""Maps a UserInfo object to a mxid.
UserInfo should have a claim that uniquely identifies users. This claim
@ -843,6 +854,8 @@ class OidcHandler:
Args:
userinfo: an object representing the user
token: a dict with the tokens obtained from the provider
user_agent: The user agent of the client making the request.
ip_address: The IP address of the client making the request.
Raises:
MappingException: if there was an error while mapping some properties
@ -899,7 +912,9 @@ class OidcHandler:
# It's the first time this user is logging in and the mapped mxid was
# not taken, register the user
registered_user_id = await self._registration_handler.register_user(
localpart=localpart, default_display_name=attributes["display_name"],
localpart=localpart,
default_display_name=attributes["display_name"],
user_agent_ips=(user_agent, ip_address),
)
await self._datastore.record_user_external_id(

26
synapse/handlers/register.py
View file

@ -26,6 +26,7 @@ from synapse.replication.http.register import (
ReplicationPostRegisterActionsServlet,
ReplicationRegisterServlet,
)
from synapse.spam_checker_api import RegistrationBehaviour
from synapse.storage.state import StateFilter
from synapse.types import RoomAlias, UserID, create_requester
@ -52,6 +53,8 @@ class RegistrationHandler(BaseHandler):
self.macaroon_gen = hs.get_macaroon_generator()
self._server_notices_mxid = hs.config.server_notices_mxid
self.spam_checker = hs.get_spam_checker()
if hs.config.worker_app:
self._register_client = ReplicationRegisterServlet.make_client(hs)
self._register_device_client = RegisterDeviceReplicationServlet.make_client(
@ -144,7 +147,7 @@ class RegistrationHandler(BaseHandler):
address=None,
bind_emails=[],
by_admin=False,
shadow_banned=False,
user_agent_ips=None,
):
"""Registers a new client on the server.
@ -162,7 +165,8 @@ class RegistrationHandler(BaseHandler):
bind_emails (List[str]): list of emails to bind to this account.
by_admin (bool): True if this registration is being made via the
admin api, otherwise False.
shadow_banned (bool): Shadow-ban the created user.
user_agent_ips (List[(str, str)]): Tuples of IP addresses and user-agents used
during the registration process.
Returns:
str: user_id
Raises:
@ -170,6 +174,24 @@ class RegistrationHandler(BaseHandler):
"""
self.check_registration_ratelimit(address)
result = self.spam_checker.check_registration_for_spam(
threepid, localpart, user_agent_ips or [],
)
if result == RegistrationBehaviour.DENY:
logger.info(
"Blocked registration of %r", localpart,
)
# We return a 429 to make it not obvious that they've been
# denied.
raise SynapseError(429, "Rate limited")
shadow_banned = result == RegistrationBehaviour.SHADOW_BAN
if shadow_banned:
logger.info(
"Shadow banning registration of %r", localpart,
)
# do not check_auth_blocking if the call is coming through the Admin API
if not by_admin:
await self.auth.check_auth_blocking(threepid=threepid)

18
synapse/handlers/saml_handler.py
View file

@ -54,6 +54,7 @@ class Saml2SessionData:
class SamlHandler:
def __init__(self, hs: "synapse.server.HomeServer"):
self.hs = hs
self._saml_client = Saml2Client(hs.config.saml2_sp_config)
self._auth = hs.get_auth()
self._auth_handler = hs.get_auth_handler()
@ -133,8 +134,14 @@ class SamlHandler:
# the dict.
self.expire_sessions()
# Pull out the user-agent and IP from the request.
user_agent = request.requestHeaders.getRawHeaders(b"User-Agent", default=[b""])[
0
].decode("ascii", "surrogateescape")
ip_address = self.hs.get_ip_from_request(request)
user_id, current_session = await self._map_saml_response_to_user(
resp_bytes, relay_state
resp_bytes, relay_state, user_agent, ip_address
)
# Complete the interactive auth session or the login.
@ -147,7 +154,11 @@ class SamlHandler:
await self._auth_handler.complete_sso_login(user_id, request, relay_state)
async def _map_saml_response_to_user(
self, resp_bytes: str, client_redirect_url: str
self,
resp_bytes: str,
client_redirect_url: str,
user_agent: str,
ip_address: str,
) -> Tuple[str, Optional[Saml2SessionData]]:
"""
Given a sample response, retrieve the cached session and user for it.
@ -155,6 +166,8 @@ class SamlHandler:
Args:
resp_bytes: The SAML response.
client_redirect_url: The redirect URL passed in by the client.
user_agent: The user agent of the client making the request.
ip_address: The IP address of the client making the request.
Returns:
Tuple of the user ID and SAML session associated with this response.
@ -291,6 +304,7 @@ class SamlHandler:
localpart=localpart,
default_display_name=displayname,
bind_emails=emails,
user_agent_ips=(user_agent, ip_address),
)
await self._datastore.record_user_external_id(

5
synapse/rest/client/v2_alpha/register.py
View file

@ -591,12 +591,17 @@ class RegisterRestServlet(RestServlet):
Codes.THREEPID_IN_USE,
)
entries = await self.store.get_user_agents_ips_to_ui_auth_session(
session_id
)
registered_user_id = await self.registration_handler.register_user(
localpart=desired_username,
password_hash=password_hash,
guest_access_token=guest_access_token,
threepid=threepid,
address=client_addr,
user_agent_ips=entries,
)
# Necessary due to auth checks prior to the threepid being
# written to the db

11
synapse/spam_checker_api/__init__.py
View file

@ -13,6 +13,7 @@
# See the License for the specific language governing permissions and
# limitations under the License.
import logging
from enum import Enum
from twisted.internet import defer
@ -25,6 +26,16 @@ if MYPY:
logger = logging.getLogger(__name__)
class RegistrationBehaviour(Enum):
"""
Enum to define whether a registration request should allowed, denied, or shadow-banned.
"""
ALLOW = "allow"
SHADOW_BAN = "shadow_ban"
DENY = "deny"
class SpamCheckerApi(object):
"""A proxy object that gets passed to spam checkers so they can get
access to rooms and other relevant information.

25
synapse/storage/databases/main/schema/delta/58/07persist_ui_auth_ips.sql Normal file
View file

@ -0,0 +1,25 @@
/* Copyright 2020 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.
*/
-- A table of the IP address and user-agent used to complete each step of a
-- user-interactive authentication session.
CREATE TABLE IF NOT EXISTS ui_auth_sessions_ips(
session_id TEXT NOT NULL,
ip TEXT NOT NULL,
user_agent TEXT NOT NULL,
UNIQUE (session_id, ip, user_agent),
FOREIGN KEY (session_id)
REFERENCES ui_auth_sessions (session_id)
);

39
synapse/storage/databases/main/ui_auth.py
View file

@ -12,7 +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 typing import Any, Dict, Optional, Union
from typing import Any, Dict, List, Optional, Tuple, Union
import attr
@ -260,6 +260,34 @@ class UIAuthWorkerStore(SQLBaseStore):
return serverdict.get(key, default)
async def add_user_agent_ip_to_ui_auth_session(
self, session_id: str, user_agent: str, ip: str,
):
"""Add the given user agent / IP to the tracking table
"""
await self.db_pool.simple_upsert(
table="ui_auth_sessions_ips",
keyvalues={"session_id": session_id, "user_agent": user_agent, "ip": ip},
values={},
desc="add_user_agent_ip_to_ui_auth_session",
)
async def get_user_agents_ips_to_ui_auth_session(
self, session_id: str,
) -> List[Tuple[str, str]]:
"""Get the given user agents / IPs used during the ui auth process
Returns:
List of user_agent/ip pairs
"""
rows = await self.db_pool.simple_select_list(
table="ui_auth_sessions_ips",
keyvalues={"session_id": session_id},
retcols=("user_agent", "ip"),
desc="get_user_agents_ips_to_ui_auth_session",
)
return [(row["user_agent"], row["ip"]) for row in rows]
class UIAuthStore(UIAuthWorkerStore):
def delete_old_ui_auth_sessions(self, expiration_time: int):
@ -285,6 +313,15 @@ class UIAuthStore(UIAuthWorkerStore):
txn.execute(sql, [expiration_time])
session_ids = [r[0] for r in txn.fetchall()]
# Delete the corresponding IP/user agents.
self.db_pool.simple_delete_many_txn(
txn,
table="ui_auth_sessions_ips",
column="session_id",
iterable=session_ids,
keyvalues={},
)
# Delete the corresponding completed credentials.
self.db_pool.simple_delete_many_txn(
txn,

18
tests/handlers/test_oidc.py
View file

@ -374,12 +374,16 @@ class OidcHandlerTestCase(HomeserverTestCase):
self.handler._fetch_userinfo = simple_async_mock(return_value=userinfo)
self.handler._map_userinfo_to_user = simple_async_mock(return_value=user_id)
self.handler._auth_handler.complete_sso_login = simple_async_mock()
request = Mock(spec=["args", "getCookie", "addCookie"])
request = Mock(
spec=["args", "getCookie", "addCookie", "requestHeaders", "getClientIP"]
)
code = "code"
state = "state"
nonce = "nonce"
client_redirect_url = "http://client/redirect"
user_agent = "Browser"
ip_address = "10.0.0.1"
session = self.handler._generate_oidc_session_token(
state=state,
nonce=nonce,
@ -392,6 +396,10 @@ class OidcHandlerTestCase(HomeserverTestCase):
request.args[b"code"] = [code.encode("utf-8")]
request.args[b"state"] = [state.encode("utf-8")]
request.requestHeaders = Mock(spec=["getRawHeaders"])
request.requestHeaders.getRawHeaders.return_value = [user_agent.encode("ascii")]
request.getClientIP.return_value = ip_address
yield defer.ensureDeferred(self.handler.handle_oidc_callback(request))
self.handler._auth_handler.complete_sso_login.assert_called_once_with(
@ -399,7 +407,9 @@ class OidcHandlerTestCase(HomeserverTestCase):
)
self.handler._exchange_code.assert_called_once_with(code)
self.handler._parse_id_token.assert_called_once_with(token, nonce=nonce)
self.handler._map_userinfo_to_user.assert_called_once_with(userinfo, token)
self.handler._map_userinfo_to_user.assert_called_once_with(
userinfo, token, user_agent, ip_address
)
self.handler._fetch_userinfo.assert_not_called()
self.handler._render_error.assert_not_called()
@ -431,7 +441,9 @@ class OidcHandlerTestCase(HomeserverTestCase):
)
self.handler._exchange_code.assert_called_once_with(code)
self.handler._parse_id_token.assert_not_called()
self.handler._map_userinfo_to_user.assert_called_once_with(userinfo, token)
self.handler._map_userinfo_to_user.assert_called_once_with(
userinfo, token, user_agent, ip_address
)
self.handler._fetch_userinfo.assert_called_once_with(token)
self.handler._render_error.assert_not_called()

52
tests/handlers/test_register.py
View file

@ -17,18 +17,21 @@ from mock import Mock
from twisted.internet import defer
from synapse.api.auth import Auth
from synapse.api.constants import UserTypes
from synapse.api.errors import Codes, ResourceLimitError, SynapseError
from synapse.handlers.register import RegistrationHandler
from synapse.spam_checker_api import RegistrationBehaviour
from synapse.types import RoomAlias, UserID, create_requester
from tests.test_utils import make_awaitable
from tests.unittest import override_config
from tests.utils import mock_getRawHeaders
from .. import unittest
class RegistrationHandlers(object):
class RegistrationHandlers:
def __init__(self, hs):
self.registration_handler = RegistrationHandler(hs)
@ -475,6 +478,53 @@ class RegistrationTestCase(unittest.HomeserverTestCase):
self.handler.register_user(localpart=invalid_user_id), SynapseError
)
def test_spam_checker_deny(self):
"""A spam checker can deny registration, which results in an error."""
class DenyAll:
def check_registration_for_spam(
self, email_threepid, username, request_info
):
return RegistrationBehaviour.DENY
# Configure a spam checker that denies all users.
spam_checker = self.hs.get_spam_checker()
spam_checker.spam_checkers = [DenyAll()]
self.get_failure(self.handler.register_user(localpart="user"), SynapseError)
def test_spam_checker_shadow_ban(self):
"""A spam checker can choose to shadow-ban a user, which allows registration to succeed."""
class BanAll:
def check_registration_for_spam(
self, email_threepid, username, request_info
):
return RegistrationBehaviour.SHADOW_BAN
# Configure a spam checker that denies all users.
spam_checker = self.hs.get_spam_checker()
spam_checker.spam_checkers = [BanAll()]
user_id = self.get_success(self.handler.register_user(localpart="user"))
# Get an access token.
token = self.macaroon_generator.generate_access_token(user_id)
self.get_success(
self.store.add_access_token_to_user(
user_id=user_id, token=token, device_id=None, valid_until_ms=None
)
)
# Ensure the user was marked as shadow-banned.
request = Mock(args={})
request.args[b"access_token"] = [token.encode("ascii")]
request.requestHeaders.getRawHeaders = mock_getRawHeaders()
auth = Auth(self.hs)
requester = self.get_success(auth.get_user_by_req(request))
self.assertTrue(requester.shadow_banned)
async def get_or_create_user(
self, requester, localpart, displayname, password_hash=None
):

6
tests/handlers/test_user_directory.py
View file

@ -238,7 +238,7 @@ class UserDirectoryTestCase(unittest.HomeserverTestCase):
def test_spam_checker(self):
"""
A user which fails to the spam checks will not appear in search results.
A user which fails the spam checks will not appear in search results.
"""
u1 = self.register_user("user1", "pass")
u1_token = self.login(u1, "pass")
@ -269,7 +269,7 @@ class UserDirectoryTestCase(unittest.HomeserverTestCase):
# Configure a spam checker that does not filter any users.
spam_checker = self.hs.get_spam_checker()
class AllowAll(object):
class AllowAll:
def check_username_for_spam(self, user_profile):
# Allow all users.
return False
@ -282,7 +282,7 @@ class UserDirectoryTestCase(unittest.HomeserverTestCase):
self.assertEqual(len(s["results"]), 1)
# Configure a spam checker that filters all users.
class BlockAll(object):
class BlockAll:
def check_username_for_spam(self, user_profile):
# All users are spammy.
return True