Add federation_domain_whitelist option (#2820)

Add federation_domain_whitelist

gives a way to restrict which domains your HS is allowed to federate with.
useful mainly for gracefully preventing a private but internet-connected HS from trying to federate to the wider public Matrix network
This commit is contained in:
Matthew Hodgson 2018-01-22 19:11:18 +01:00 committed by GitHub
parent d84f65255e
commit ab9f844aaf
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14 changed files with 146 additions and 7 deletions

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@ -141,6 +141,32 @@ class RegistrationError(SynapseError):
pass
class FederationDeniedError(SynapseError):
"""An error raised when the server tries to federate with a server which
is not on its federation whitelist.
Attributes:
destination (str): The destination which has been denied
"""
def __init__(self, destination):
"""Raised by federation client or server to indicate that we are
are deliberately not attempting to contact a given server because it is
not on our federation whitelist.
Args:
destination (str): the domain in question
"""
self.destination = destination
super(FederationDeniedError, self).__init__(
code=403,
msg="Federation denied with %s." % (self.destination,),
errcode=Codes.FORBIDDEN,
)
class InteractiveAuthIncompleteError(Exception):
"""An error raised when UI auth is not yet complete

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@ -55,6 +55,17 @@ class ServerConfig(Config):
"block_non_admin_invites", False,
)
# FIXME: federation_domain_whitelist needs sytests
self.federation_domain_whitelist = None
federation_domain_whitelist = config.get(
"federation_domain_whitelist", None
)
# turn the whitelist into a hash for speed of lookup
if federation_domain_whitelist is not None:
self.federation_domain_whitelist = {}
for domain in federation_domain_whitelist:
self.federation_domain_whitelist[domain] = True
if self.public_baseurl is not None:
if self.public_baseurl[-1] != '/':
self.public_baseurl += '/'
@ -210,6 +221,17 @@ class ServerConfig(Config):
# (except those sent by local server admins). The default is False.
# block_non_admin_invites: True
# Restrict federation to the following whitelist of domains.
# N.B. we recommend also firewalling your federation listener to limit
# inbound federation traffic as early as possible, rather than relying
# purely on this application-layer restriction. If not specified, the
# default is to whitelist everything.
#
# federation_domain_whitelist:
# - lon.example.com
# - nyc.example.com
# - syd.example.com
# List of ports that Synapse should listen on, their purpose and their
# configuration.
listeners:

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@ -23,7 +23,7 @@ from twisted.internet import defer
from synapse.api.constants import Membership
from synapse.api.errors import (
CodeMessageException, HttpResponseException, SynapseError,
CodeMessageException, HttpResponseException, SynapseError, FederationDeniedError
)
from synapse.events import builder
from synapse.federation.federation_base import (
@ -266,6 +266,9 @@ class FederationClient(FederationBase):
except NotRetryingDestination as e:
logger.info(e.message)
continue
except FederationDeniedError as e:
logger.info(e.message)
continue
except Exception as e:
pdu_attempts[destination] = now

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@ -19,7 +19,7 @@ from twisted.internet import defer
from .persistence import TransactionActions
from .units import Transaction, Edu
from synapse.api.errors import HttpResponseException
from synapse.api.errors import HttpResponseException, FederationDeniedError
from synapse.util import logcontext, PreserveLoggingContext
from synapse.util.async import run_on_reactor
from synapse.util.retryutils import NotRetryingDestination, get_retry_limiter
@ -490,6 +490,8 @@ class TransactionQueue(object):
(e.retry_last_ts + e.retry_interval) / 1000.0
),
)
except FederationDeniedError as e:
logger.info(e)
except Exception as e:
logger.warn(
"TX [%s] Failed to send transaction: %s",

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@ -212,6 +212,9 @@ class TransportLayerClient(object):
Fails with ``NotRetryingDestination`` if we are not yet ready
to retry this server.
Fails with ``FederationDeniedError`` if the remote destination
is not in our federation whitelist
"""
valid_memberships = {Membership.JOIN, Membership.LEAVE}
if membership not in valid_memberships:

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@ -16,7 +16,7 @@
from twisted.internet import defer
from synapse.api.urls import FEDERATION_PREFIX as PREFIX
from synapse.api.errors import Codes, SynapseError
from synapse.api.errors import Codes, SynapseError, FederationDeniedError
from synapse.http.server import JsonResource
from synapse.http.servlet import (
parse_json_object_from_request, parse_integer_from_args, parse_string_from_args,
@ -81,6 +81,7 @@ class Authenticator(object):
self.keyring = hs.get_keyring()
self.server_name = hs.hostname
self.store = hs.get_datastore()
self.federation_domain_whitelist = hs.config.federation_domain_whitelist
# A method just so we can pass 'self' as the authenticator to the Servlets
@defer.inlineCallbacks
@ -92,6 +93,12 @@ class Authenticator(object):
"signatures": {},
}
if (
self.federation_domain_whitelist is not None and
self.server_name not in self.federation_domain_whitelist
):
raise FederationDeniedError(self.server_name)
if content is not None:
json_request["content"] = content

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@ -14,6 +14,7 @@
# limitations under the License.
from synapse.api import errors
from synapse.api.constants import EventTypes
from synapse.api.errors import FederationDeniedError
from synapse.util import stringutils
from synapse.util.async import Linearizer
from synapse.util.caches.expiringcache import ExpiringCache
@ -513,6 +514,9 @@ class DeviceListEduUpdater(object):
# This makes it more likely that the device lists will
# eventually become consistent.
return
except FederationDeniedError as e:
logger.info(e)
return
except Exception:
# TODO: Remember that we are now out of sync and try again
# later

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@ -19,7 +19,9 @@ import logging
from canonicaljson import encode_canonical_json
from twisted.internet import defer
from synapse.api.errors import SynapseError, CodeMessageException
from synapse.api.errors import (
SynapseError, CodeMessageException, FederationDeniedError,
)
from synapse.types import get_domain_from_id, UserID
from synapse.util.logcontext import preserve_fn, make_deferred_yieldable
from synapse.util.retryutils import NotRetryingDestination
@ -140,6 +142,10 @@ class E2eKeysHandler(object):
failures[destination] = {
"status": 503, "message": "Not ready for retry",
}
except FederationDeniedError as e:
failures[destination] = {
"status": 403, "message": "Federation Denied",
}
except Exception as e:
# include ConnectionRefused and other errors
failures[destination] = {

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@ -22,6 +22,7 @@ from ._base import BaseHandler
from synapse.api.errors import (
AuthError, FederationError, StoreError, CodeMessageException, SynapseError,
FederationDeniedError,
)
from synapse.api.constants import EventTypes, Membership, RejectedReason
from synapse.events.validator import EventValidator
@ -782,6 +783,9 @@ class FederationHandler(BaseHandler):
except NotRetryingDestination as e:
logger.info(e.message)
continue
except FederationDeniedError as e:
logger.info(e)
continue
except Exception as e:
logger.exception(
"Failed to backfill from %s because %s",

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@ -27,7 +27,7 @@ import synapse.metrics
from canonicaljson import encode_canonical_json
from synapse.api.errors import (
SynapseError, Codes, HttpResponseException,
SynapseError, Codes, HttpResponseException, FederationDeniedError,
)
from signedjson.sign import sign_json
@ -123,11 +123,22 @@ class MatrixFederationHttpClient(object):
Fails with ``HTTPRequestException``: if we get an HTTP response
code >= 300.
Fails with ``NotRetryingDestination`` if we are not yet ready
to retry this server.
Fails with ``FederationDeniedError`` if this destination
is not on our federation whitelist
(May also fail with plenty of other Exceptions for things like DNS
failures, connection failures, SSL failures.)
"""
if (
self.hs.config.federation_domain_whitelist and
destination not in self.hs.config.federation_domain_whitelist
):
raise FederationDeniedError(destination)
limiter = yield synapse.util.retryutils.get_retry_limiter(
destination,
self.clock,
@ -308,6 +319,9 @@ class MatrixFederationHttpClient(object):
Fails with ``NotRetryingDestination`` if we are not yet ready
to retry this server.
Fails with ``FederationDeniedError`` if this destination
is not on our federation whitelist
"""
if not json_data_callback:
@ -368,6 +382,9 @@ class MatrixFederationHttpClient(object):
Fails with ``NotRetryingDestination`` if we are not yet ready
to retry this server.
Fails with ``FederationDeniedError`` if this destination
is not on our federation whitelist
"""
def body_callback(method, url_bytes, headers_dict):
@ -422,6 +439,9 @@ class MatrixFederationHttpClient(object):
Fails with ``NotRetryingDestination`` if we are not yet ready
to retry this server.
Fails with ``FederationDeniedError`` if this destination
is not on our federation whitelist
"""
logger.debug("get_json args: %s", args)
@ -475,6 +495,9 @@ class MatrixFederationHttpClient(object):
Fails with ``NotRetryingDestination`` if we are not yet ready
to retry this server.
Fails with ``FederationDeniedError`` if this destination
is not on our federation whitelist
"""
response = yield self._request(
@ -518,6 +541,9 @@ class MatrixFederationHttpClient(object):
Fails with ``NotRetryingDestination`` if we are not yet ready
to retry this server.
Fails with ``FederationDeniedError`` if this destination
is not on our federation whitelist
"""
encoded_args = {}

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@ -93,6 +93,7 @@ class RemoteKey(Resource):
self.store = hs.get_datastore()
self.version_string = hs.version_string
self.clock = hs.get_clock()
self.federation_domain_whitelist = hs.config.federation_domain_whitelist
def render_GET(self, request):
self.async_render_GET(request)
@ -137,6 +138,13 @@ class RemoteKey(Resource):
logger.info("Handling query for keys %r", query)
store_queries = []
for server_name, key_ids in query.items():
if (
self.federation_domain_whitelist is not None and
server_name not in self.federation_domain_whitelist
):
logger.debug("Federation denied with %s", server_name)
continue
if not key_ids:
key_ids = (None,)
for key_id in key_ids:

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@ -32,8 +32,9 @@ from .media_storage import MediaStorage
from synapse.http.matrixfederationclient import MatrixFederationHttpClient
from synapse.util.stringutils import random_string
from synapse.api.errors import SynapseError, HttpResponseException, \
NotFoundError
from synapse.api.errors import (
SynapseError, HttpResponseException, NotFoundError, FederationDeniedError,
)
from synapse.util.async import Linearizer
from synapse.util.stringutils import is_ascii
@ -75,6 +76,8 @@ class MediaRepository(object):
self.recently_accessed_remotes = set()
self.recently_accessed_locals = set()
self.federation_domain_whitelist = hs.config.federation_domain_whitelist
# List of StorageProviders where we should search for media and
# potentially upload to.
storage_providers = []
@ -216,6 +219,12 @@ class MediaRepository(object):
Deferred: Resolves once a response has successfully been written
to request
"""
if (
self.federation_domain_whitelist is not None and
server_name not in self.federation_domain_whitelist
):
raise FederationDeniedError(server_name)
self.mark_recently_accessed(server_name, media_id)
# We linearize here to ensure that we don't try and download remote
@ -250,6 +259,12 @@ class MediaRepository(object):
Returns:
Deferred[dict]: The media_info of the file
"""
if (
self.federation_domain_whitelist is not None and
server_name not in self.federation_domain_whitelist
):
raise FederationDeniedError(server_name)
# We linearize here to ensure that we don't try and download remote
# media multiple times concurrently
key = (server_name, media_id)

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@ -26,6 +26,18 @@ logger = logging.getLogger(__name__)
class NotRetryingDestination(Exception):
def __init__(self, retry_last_ts, retry_interval, destination):
"""Raised by the limiter (and federation client) to indicate that we are
are deliberately not attempting to contact a given server.
Args:
retry_last_ts (int): the unix ts in milliseconds of our last attempt
to contact the server. 0 indicates that the last attempt was
successful or that we've never actually attempted to connect.
retry_interval (int): the time in milliseconds to wait until the next
attempt.
destination (str): the domain in question
"""
msg = "Not retrying server %s." % (destination,)
super(NotRetryingDestination, self).__init__(msg)

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@ -57,6 +57,7 @@ def setup_test_homeserver(name="test", datastore=None, config=None, **kargs):
config.worker_app = None
config.email_enable_notifs = False
config.block_non_admin_invites = False
config.federation_domain_whitelist = None
# disable user directory updates, because they get done in the
# background, which upsets the test runner.