From 33f469ba19586bbafa0cf2c7d7c35463bdab87eb Mon Sep 17 00:00:00 2001 From: Richard van der Hoff Date: Tue, 1 May 2018 16:19:39 +0100 Subject: [PATCH 1/2] Apply some limits to depth to counter abuse * When creating a new event, cap its depth to 2^63 - 1 * When receiving events, reject any without a sensible depth As per https://docs.google.com/document/d/1I3fi2S-XnpO45qrpCsowZv8P8dHcNZ4fsBsbOW7KABI --- synapse/api/constants.py | 3 +++ synapse/federation/federation_base.py | 21 ++++++++++++++++++--- synapse/handlers/message.py | 6 +++++- 3 files changed, 26 insertions(+), 4 deletions(-) diff --git a/synapse/api/constants.py b/synapse/api/constants.py index 489efb7f8..5baba4396 100644 --- a/synapse/api/constants.py +++ b/synapse/api/constants.py @@ -16,6 +16,9 @@ """Contains constants from the specification.""" +# the "depth" field on events is limited to 2**63 - 1 +MAX_DEPTH = 2**63 - 1 + class Membership(object): diff --git a/synapse/federation/federation_base.py b/synapse/federation/federation_base.py index 79eaa3103..4cc98a3fe 100644 --- a/synapse/federation/federation_base.py +++ b/synapse/federation/federation_base.py @@ -14,7 +14,10 @@ # limitations under the License. import logging -from synapse.api.errors import SynapseError +import six + +from synapse.api.constants import MAX_DEPTH +from synapse.api.errors import SynapseError, Codes from synapse.crypto.event_signing import check_event_content_hash from synapse.events import FrozenEvent from synapse.events.utils import prune_event @@ -190,11 +193,23 @@ def event_from_pdu_json(pdu_json, outlier=False): FrozenEvent Raises: - SynapseError: if the pdu is missing required fields + SynapseError: if the pdu is missing required fields or is otherwise + not a valid matrix event """ # we could probably enforce a bunch of other fields here (room_id, sender, # origin, etc etc) - assert_params_in_request(pdu_json, ('event_id', 'type')) + assert_params_in_request(pdu_json, ('event_id', 'type', 'depth')) + + depth = pdu_json['depth'] + if not isinstance(depth, six.integer_types): + raise SynapseError(400, "Depth %r not an intger" % (depth, ), + Codes.BAD_JSON) + + if depth < 0: + raise SynapseError(400, "Depth too small", Codes.BAD_JSON) + elif depth > MAX_DEPTH: + raise SynapseError(400, "Depth too large", Codes.BAD_JSON) + event = FrozenEvent( pdu_json ) diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py index 21628a854..53beb2b9a 100644 --- a/synapse/handlers/message.py +++ b/synapse/handlers/message.py @@ -16,7 +16,7 @@ from twisted.internet import defer, reactor from twisted.python.failure import Failure -from synapse.api.constants import EventTypes, Membership +from synapse.api.constants import EventTypes, Membership, MAX_DEPTH from synapse.api.errors import AuthError, Codes, SynapseError from synapse.crypto.event_signing import add_hashes_and_signatures from synapse.events.utils import serialize_event @@ -624,6 +624,10 @@ class EventCreationHandler(object): if prev_events_and_hashes: depth = max([d for _, _, d in prev_events_and_hashes]) + 1 + # we cap depth of generated events, to ensure that they are not + # rejected by other servers (and so that they can be persisted in + # the db) + depth = min(depth, MAX_DEPTH) else: depth = 1 From d858f3bd4e0513bea2fae43b23250b979b971407 Mon Sep 17 00:00:00 2001 From: Richard van der Hoff Date: Thu, 26 Apr 2018 12:34:40 +0100 Subject: [PATCH 2/2] Miscellaneous fixes to python_dependencies * add some doc about wtf this thing does * pin Twisted to < 18.4 * add explicit dep on six (fixes #3089) --- synapse/python_dependencies.py | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/synapse/python_dependencies.py b/synapse/python_dependencies.py index 5cabf7dab..711cbb6c5 100644 --- a/synapse/python_dependencies.py +++ b/synapse/python_dependencies.py @@ -1,5 +1,6 @@ # Copyright 2015, 2016 OpenMarket Ltd # Copyright 2017 Vector Creations Ltd +# 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. @@ -18,6 +19,18 @@ from distutils.version import LooseVersion logger = logging.getLogger(__name__) +# this dict maps from python package name to a list of modules we expect it to +# provide. +# +# the key is a "requirement specifier", as used as a parameter to `pip +# install`[1], or an `install_requires` argument to `setuptools.setup` [2]. +# +# the value is a sequence of strings; each entry should be the name of the +# python module, optionally followed by a version assertion which can be either +# ">=" or "==". +# +# [1] https://pip.pypa.io/en/stable/reference/pip_install/#requirement-specifiers. +# [2] https://setuptools.readthedocs.io/en/latest/setuptools.html#declaring-dependencies REQUIREMENTS = { "jsonschema>=2.5.1": ["jsonschema>=2.5.1"], "frozendict>=0.4": ["frozendict"], @@ -26,7 +39,11 @@ REQUIREMENTS = { "signedjson>=1.0.0": ["signedjson>=1.0.0"], "pynacl>=1.2.1": ["nacl>=1.2.1", "nacl.bindings"], "service_identity>=1.0.0": ["service_identity>=1.0.0"], - "Twisted>=16.0.0": ["twisted>=16.0.0"], + + # we break under Twisted 18.4 + # (https://github.com/matrix-org/synapse/issues/3135) + "Twisted>=16.0.0,<18.4": ["twisted>=16.0.0"], + "pyopenssl>=0.14": ["OpenSSL>=0.14"], "pyyaml": ["yaml"], "pyasn1": ["pyasn1"], @@ -39,6 +56,7 @@ REQUIREMENTS = { "pymacaroons-pynacl": ["pymacaroons"], "msgpack-python>=0.3.0": ["msgpack"], "phonenumbers>=8.2.0": ["phonenumbers"], + "six": ["six"], } CONDITIONAL_REQUIREMENTS = { "web_client": {