Add experimental support for MSC3202: allowing application services to masquerade as specific devices. (#11538)

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reivilibre 2021-12-15 10:40:52 +00:00 committed by GitHub
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5 changed files with 162 additions and 14 deletions

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@ -0,0 +1 @@
Add experimental support for MSC3202: allowing application services to masquerade as specific devices.

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@ -155,7 +155,11 @@ class Auth:
access_token = self.get_access_token_from_request(request)
user_id, app_service = await self._get_appservice_user_id(request)
(
user_id,
device_id,
app_service,
) = await self._get_appservice_user_id_and_device_id(request)
if user_id and app_service:
if ip_addr and self._track_appservice_user_ips:
await self.store.insert_client_ip(
@ -163,16 +167,22 @@ class Auth:
access_token=access_token,
ip=ip_addr,
user_agent=user_agent,
device_id="dummy-device", # stubbed
device_id="dummy-device"
if device_id is None
else device_id, # stubbed
)
requester = create_requester(user_id, app_service=app_service)
requester = create_requester(
user_id, app_service=app_service, device_id=device_id
)
request.requester = user_id
if user_id in self._force_tracing_for_users:
opentracing.force_tracing()
opentracing.set_tag("authenticated_entity", user_id)
opentracing.set_tag("user_id", user_id)
if device_id is not None:
opentracing.set_tag("device_id", device_id)
opentracing.set_tag("appservice_id", app_service.id)
return requester
@ -274,33 +284,81 @@ class Auth:
403, "Application service has not registered this user (%s)" % user_id
)
async def _get_appservice_user_id(
async def _get_appservice_user_id_and_device_id(
self, request: Request
) -> Tuple[Optional[str], Optional[ApplicationService]]:
) -> Tuple[Optional[str], Optional[str], Optional[ApplicationService]]:
"""
Given a request, reads the request parameters to determine:
- whether it's an application service that's making this request
- what user the application service should be treated as controlling
(the user_id URI parameter allows an application service to masquerade
any applicable user in its namespace)
- what device the application service should be treated as controlling
(the device_id[^1] URI parameter allows an application service to masquerade
as any device that exists for the relevant user)
[^1] Unstable and provided by MSC3202.
Must use `org.matrix.msc3202.device_id` in place of `device_id` for now.
Returns:
3-tuple of
(user ID?, device ID?, application service?)
Postconditions:
- If an application service is returned, so is a user ID
- A user ID is never returned without an application service
- A device ID is never returned without a user ID or an application service
- The returned application service, if present, is permitted to control the
returned user ID.
- The returned device ID, if present, has been checked to be a valid device ID
for the returned user ID.
"""
DEVICE_ID_ARG_NAME = b"org.matrix.msc3202.device_id"
app_service = self.store.get_app_service_by_token(
self.get_access_token_from_request(request)
)
if app_service is None:
return None, None
return None, None, None
if app_service.ip_range_whitelist:
ip_address = IPAddress(request.getClientIP())
if ip_address not in app_service.ip_range_whitelist:
return None, None
return None, None, None
# This will always be set by the time Twisted calls us.
assert request.args is not None
if b"user_id" not in request.args:
return app_service.sender, app_service
if b"user_id" in request.args:
effective_user_id = request.args[b"user_id"][0].decode("utf8")
await self.validate_appservice_can_control_user_id(
app_service, effective_user_id
)
else:
effective_user_id = app_service.sender
user_id = request.args[b"user_id"][0].decode("utf8")
await self.validate_appservice_can_control_user_id(app_service, user_id)
effective_device_id: Optional[str] = None
if app_service.sender == user_id:
return app_service.sender, app_service
if (
self.hs.config.experimental.msc3202_device_masquerading_enabled
and DEVICE_ID_ARG_NAME in request.args
):
effective_device_id = request.args[DEVICE_ID_ARG_NAME][0].decode("utf8")
# We only just set this so it can't be None!
assert effective_device_id is not None
device_opt = await self.store.get_device(
effective_user_id, effective_device_id
)
if device_opt is None:
# For now, use 400 M_EXCLUSIVE if the device doesn't exist.
# This is an open thread of discussion on MSC3202 as of 2021-12-09.
raise AuthError(
400,
f"Application service trying to use a device that doesn't exist ('{effective_device_id}' for {effective_user_id})",
Codes.EXCLUSIVE,
)
return user_id, app_service
return effective_user_id, effective_device_id, app_service
async def get_user_by_access_token(
self,

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@ -49,3 +49,8 @@ class ExperimentalConfig(Config):
# MSC3030 (Jump to date API endpoint)
self.msc3030_enabled: bool = experimental.get("msc3030_enabled", False)
# The portion of MSC3202 which is related to device masquerading.
self.msc3202_device_masquerading_enabled: bool = experimental.get(
"msc3202_device_masquerading", False
)

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@ -128,6 +128,26 @@ class DeviceWorkerStore(SQLBaseStore):
allow_none=True,
)
async def get_device_opt(
self, user_id: str, device_id: str
) -> Optional[Dict[str, Any]]:
"""Retrieve a device. Only returns devices that are not marked as
hidden.
Args:
user_id: The ID of the user which owns the device
device_id: The ID of the device to retrieve
Returns:
A dict containing the device information, or None if the device does not exist.
"""
return await self.db_pool.simple_select_one(
table="devices",
keyvalues={"user_id": user_id, "device_id": device_id, "hidden": False},
retcols=("user_id", "device_id", "display_name"),
desc="get_device",
allow_none=True,
)
async def get_devices_by_user(self, user_id: str) -> Dict[str, Dict[str, str]]:
"""Retrieve all of a user's registered devices. Only returns devices
that are not marked as hidden.

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@ -31,6 +31,7 @@ from synapse.types import Requester
from tests import unittest
from tests.test_utils import simple_async_mock
from tests.unittest import override_config
from tests.utils import mock_getRawHeaders
@ -210,6 +211,69 @@ class AuthTestCase(unittest.HomeserverTestCase):
request.requestHeaders.getRawHeaders = mock_getRawHeaders()
self.get_failure(self.auth.get_user_by_req(request), AuthError)
@override_config({"experimental_features": {"msc3202_device_masquerading": True}})
def test_get_user_by_req_appservice_valid_token_valid_device_id(self):
"""
Tests that when an application service passes the device_id URL parameter
with the ID of a valid device for the user in question,
the requester instance tracks that device ID.
"""
masquerading_user_id = b"@doppelganger:matrix.org"
masquerading_device_id = b"DOPPELDEVICE"
app_service = Mock(
token="foobar", url="a_url", sender=self.test_user, ip_range_whitelist=None
)
app_service.is_interested_in_user = Mock(return_value=True)
self.store.get_app_service_by_token = Mock(return_value=app_service)
# This just needs to return a truth-y value.
self.store.get_user_by_id = simple_async_mock({"is_guest": False})
self.store.get_user_by_access_token = simple_async_mock(None)
# This also needs to just return a truth-y value
self.store.get_device = simple_async_mock({"hidden": False})
request = Mock(args={})
request.getClientIP.return_value = "127.0.0.1"
request.args[b"access_token"] = [self.test_token]
request.args[b"user_id"] = [masquerading_user_id]
request.args[b"org.matrix.msc3202.device_id"] = [masquerading_device_id]
request.requestHeaders.getRawHeaders = mock_getRawHeaders()
requester = self.get_success(self.auth.get_user_by_req(request))
self.assertEquals(
requester.user.to_string(), masquerading_user_id.decode("utf8")
)
self.assertEquals(requester.device_id, masquerading_device_id.decode("utf8"))
@override_config({"experimental_features": {"msc3202_device_masquerading": True}})
def test_get_user_by_req_appservice_valid_token_invalid_device_id(self):
"""
Tests that when an application service passes the device_id URL parameter
with an ID that is not a valid device ID for the user in question,
the request fails with the appropriate error code.
"""
masquerading_user_id = b"@doppelganger:matrix.org"
masquerading_device_id = b"NOT_A_REAL_DEVICE_ID"
app_service = Mock(
token="foobar", url="a_url", sender=self.test_user, ip_range_whitelist=None
)
app_service.is_interested_in_user = Mock(return_value=True)
self.store.get_app_service_by_token = Mock(return_value=app_service)
# This just needs to return a truth-y value.
self.store.get_user_by_id = simple_async_mock({"is_guest": False})
self.store.get_user_by_access_token = simple_async_mock(None)
# This also needs to just return a falsey value
self.store.get_device = simple_async_mock(None)
request = Mock(args={})
request.getClientIP.return_value = "127.0.0.1"
request.args[b"access_token"] = [self.test_token]
request.args[b"user_id"] = [masquerading_user_id]
request.args[b"org.matrix.msc3202.device_id"] = [masquerading_device_id]
request.requestHeaders.getRawHeaders = mock_getRawHeaders()
failure = self.get_failure(self.auth.get_user_by_req(request), AuthError)
self.assertEquals(failure.value.code, 400)
self.assertEquals(failure.value.errcode, Codes.EXCLUSIVE)
def test_get_user_from_macaroon(self):
self.store.get_user_by_access_token = simple_async_mock(
TokenLookupResult(user_id="@baldrick:matrix.org", device_id="device")