462 lines
16 KiB
Python
462 lines
16 KiB
Python
# -*- coding: utf-8 -*-
|
|
# Copyright 2014, 2015 OpenMarket 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 synapse.crypto.keyclient import fetch_server_key
|
|
from twisted.internet import defer
|
|
from syutil.crypto.jsonsign import (
|
|
verify_signed_json, signature_ids, sign_json, encode_canonical_json
|
|
)
|
|
from syutil.crypto.signing_key import (
|
|
is_signing_algorithm_supported, decode_verify_key_bytes
|
|
)
|
|
from syutil.base64util import decode_base64, encode_base64
|
|
from synapse.api.errors import SynapseError, Codes
|
|
|
|
from synapse.util.retryutils import get_retry_limiter
|
|
|
|
from synapse.util.async import ObservableDeferred
|
|
|
|
from OpenSSL import crypto
|
|
|
|
import urllib
|
|
import hashlib
|
|
import logging
|
|
|
|
|
|
logger = logging.getLogger(__name__)
|
|
|
|
|
|
class Keyring(object):
|
|
def __init__(self, hs):
|
|
self.store = hs.get_datastore()
|
|
self.clock = hs.get_clock()
|
|
self.client = hs.get_http_client()
|
|
self.config = hs.get_config()
|
|
self.perspective_servers = self.config.perspectives
|
|
self.hs = hs
|
|
|
|
self.key_downloads = {}
|
|
|
|
@defer.inlineCallbacks
|
|
def verify_json_for_server(self, server_name, json_object):
|
|
logger.debug("Verifying for %s", server_name)
|
|
key_ids = signature_ids(json_object, server_name)
|
|
if not key_ids:
|
|
raise SynapseError(
|
|
400,
|
|
"Not signed with a supported algorithm",
|
|
Codes.UNAUTHORIZED,
|
|
)
|
|
try:
|
|
verify_key = yield self.get_server_verify_key(server_name, key_ids)
|
|
except IOError as e:
|
|
logger.warn(
|
|
"Got IOError when downloading keys for %s: %s %s",
|
|
server_name, type(e).__name__, str(e.message),
|
|
)
|
|
raise SynapseError(
|
|
502,
|
|
"Error downloading keys for %s" % (server_name,),
|
|
Codes.UNAUTHORIZED,
|
|
)
|
|
except Exception as e:
|
|
logger.warn(
|
|
"Got Exception when downloading keys for %s: %s %s",
|
|
server_name, type(e).__name__, str(e.message),
|
|
)
|
|
raise SynapseError(
|
|
401,
|
|
"No key for %s with id %s" % (server_name, key_ids),
|
|
Codes.UNAUTHORIZED,
|
|
)
|
|
|
|
try:
|
|
verify_signed_json(json_object, server_name, verify_key)
|
|
except:
|
|
raise SynapseError(
|
|
401,
|
|
"Invalid signature for server %s with key %s:%s" % (
|
|
server_name, verify_key.alg, verify_key.version
|
|
),
|
|
Codes.UNAUTHORIZED,
|
|
)
|
|
|
|
@defer.inlineCallbacks
|
|
def get_server_verify_key(self, server_name, key_ids):
|
|
"""Finds a verification key for the server with one of the key ids.
|
|
Trys to fetch the key from a trusted perspective server first.
|
|
Args:
|
|
server_name(str): The name of the server to fetch a key for.
|
|
keys_ids (list of str): The key_ids to check for.
|
|
"""
|
|
cached = yield self.store.get_server_verify_keys(server_name, key_ids)
|
|
|
|
if cached:
|
|
defer.returnValue(cached[0])
|
|
return
|
|
|
|
download = self.key_downloads.get(server_name)
|
|
|
|
if download is None:
|
|
download = self._get_server_verify_key_impl(server_name, key_ids)
|
|
download = ObservableDeferred(
|
|
download,
|
|
consumeErrors=True
|
|
)
|
|
self.key_downloads[server_name] = download
|
|
|
|
@download.addBoth
|
|
def callback(ret):
|
|
del self.key_downloads[server_name]
|
|
return ret
|
|
|
|
r = yield download.observe()
|
|
defer.returnValue(r)
|
|
|
|
@defer.inlineCallbacks
|
|
def _get_server_verify_key_impl(self, server_name, key_ids):
|
|
keys = None
|
|
|
|
perspective_results = []
|
|
for perspective_name, perspective_keys in self.perspective_servers.items():
|
|
@defer.inlineCallbacks
|
|
def get_key():
|
|
try:
|
|
result = yield self.get_server_verify_key_v2_indirect(
|
|
server_name, key_ids, perspective_name, perspective_keys
|
|
)
|
|
defer.returnValue(result)
|
|
except:
|
|
logging.info(
|
|
"Unable to getting key %r for %r from %r",
|
|
key_ids, server_name, perspective_name,
|
|
)
|
|
perspective_results.append(get_key())
|
|
|
|
perspective_results = yield defer.gatherResults(perspective_results)
|
|
|
|
for results in perspective_results:
|
|
if results is not None:
|
|
keys = results
|
|
|
|
limiter = yield get_retry_limiter(
|
|
server_name,
|
|
self.clock,
|
|
self.store,
|
|
)
|
|
|
|
with limiter:
|
|
if keys is None:
|
|
try:
|
|
keys = yield self.get_server_verify_key_v2_direct(
|
|
server_name, key_ids
|
|
)
|
|
except:
|
|
pass
|
|
|
|
keys = yield self.get_server_verify_key_v1_direct(
|
|
server_name, key_ids
|
|
)
|
|
|
|
for key_id in key_ids:
|
|
if key_id in keys:
|
|
defer.returnValue(keys[key_id])
|
|
return
|
|
raise ValueError("No verification key found for given key ids")
|
|
|
|
@defer.inlineCallbacks
|
|
def get_server_verify_key_v2_indirect(self, server_name, key_ids,
|
|
perspective_name,
|
|
perspective_keys):
|
|
limiter = yield get_retry_limiter(
|
|
perspective_name, self.clock, self.store
|
|
)
|
|
|
|
with limiter:
|
|
# TODO(mark): Set the minimum_valid_until_ts to that needed by
|
|
# the events being validated or the current time if validating
|
|
# an incoming request.
|
|
responses = yield self.client.post_json(
|
|
destination=perspective_name,
|
|
path=b"/_matrix/key/v2/query",
|
|
data={
|
|
u"server_keys": {
|
|
server_name: {
|
|
key_id: {
|
|
u"minimum_valid_until_ts": 0
|
|
} for key_id in key_ids
|
|
}
|
|
}
|
|
},
|
|
)
|
|
|
|
keys = {}
|
|
|
|
for response in responses:
|
|
if (u"signatures" not in response
|
|
or perspective_name not in response[u"signatures"]):
|
|
raise ValueError(
|
|
"Key response not signed by perspective server"
|
|
" %r" % (perspective_name,)
|
|
)
|
|
|
|
verified = False
|
|
for key_id in response[u"signatures"][perspective_name]:
|
|
if key_id in perspective_keys:
|
|
verify_signed_json(
|
|
response,
|
|
perspective_name,
|
|
perspective_keys[key_id]
|
|
)
|
|
verified = True
|
|
|
|
if not verified:
|
|
logging.info(
|
|
"Response from perspective server %r not signed with a"
|
|
" known key, signed with: %r, known keys: %r",
|
|
perspective_name,
|
|
list(response[u"signatures"][perspective_name]),
|
|
list(perspective_keys)
|
|
)
|
|
raise ValueError(
|
|
"Response not signed with a known key for perspective"
|
|
" server %r" % (perspective_name,)
|
|
)
|
|
|
|
response_keys = yield self.process_v2_response(
|
|
server_name, perspective_name, response
|
|
)
|
|
|
|
keys.update(response_keys)
|
|
|
|
yield self.store_keys(
|
|
server_name=server_name,
|
|
from_server=perspective_name,
|
|
verify_keys=keys,
|
|
)
|
|
|
|
defer.returnValue(keys)
|
|
|
|
@defer.inlineCallbacks
|
|
def get_server_verify_key_v2_direct(self, server_name, key_ids):
|
|
|
|
keys = {}
|
|
|
|
for requested_key_id in key_ids:
|
|
if requested_key_id in keys:
|
|
continue
|
|
|
|
(response, tls_certificate) = yield fetch_server_key(
|
|
server_name, self.hs.tls_context_factory,
|
|
path=(b"/_matrix/key/v2/server/%s" % (
|
|
urllib.quote(requested_key_id),
|
|
)).encode("ascii"),
|
|
)
|
|
|
|
if (u"signatures" not in response
|
|
or server_name not in response[u"signatures"]):
|
|
raise ValueError("Key response not signed by remote server")
|
|
|
|
if "tls_fingerprints" not in response:
|
|
raise ValueError("Key response missing TLS fingerprints")
|
|
|
|
certificate_bytes = crypto.dump_certificate(
|
|
crypto.FILETYPE_ASN1, tls_certificate
|
|
)
|
|
sha256_fingerprint = hashlib.sha256(certificate_bytes).digest()
|
|
sha256_fingerprint_b64 = encode_base64(sha256_fingerprint)
|
|
|
|
response_sha256_fingerprints = set()
|
|
for fingerprint in response[u"tls_fingerprints"]:
|
|
if u"sha256" in fingerprint:
|
|
response_sha256_fingerprints.add(fingerprint[u"sha256"])
|
|
|
|
if sha256_fingerprint_b64 not in response_sha256_fingerprints:
|
|
raise ValueError("TLS certificate not allowed by fingerprints")
|
|
|
|
response_keys = yield self.process_v2_response(
|
|
server_name=server_name,
|
|
from_server=server_name,
|
|
requested_id=requested_key_id,
|
|
response_json=response,
|
|
)
|
|
|
|
keys.update(response_keys)
|
|
|
|
yield self.store_keys(
|
|
server_name=server_name,
|
|
from_server=server_name,
|
|
verify_keys=keys,
|
|
)
|
|
|
|
defer.returnValue(keys)
|
|
|
|
@defer.inlineCallbacks
|
|
def process_v2_response(self, server_name, from_server, response_json,
|
|
requested_id=None):
|
|
time_now_ms = self.clock.time_msec()
|
|
response_keys = {}
|
|
verify_keys = {}
|
|
for key_id, key_data in response_json["verify_keys"].items():
|
|
if is_signing_algorithm_supported(key_id):
|
|
key_base64 = key_data["key"]
|
|
key_bytes = decode_base64(key_base64)
|
|
verify_key = decode_verify_key_bytes(key_id, key_bytes)
|
|
verify_key.time_added = time_now_ms
|
|
verify_keys[key_id] = verify_key
|
|
|
|
old_verify_keys = {}
|
|
for key_id, key_data in response_json["old_verify_keys"].items():
|
|
if is_signing_algorithm_supported(key_id):
|
|
key_base64 = key_data["key"]
|
|
key_bytes = decode_base64(key_base64)
|
|
verify_key = decode_verify_key_bytes(key_id, key_bytes)
|
|
verify_key.expired = key_data["expired_ts"]
|
|
verify_key.time_added = time_now_ms
|
|
old_verify_keys[key_id] = verify_key
|
|
|
|
for key_id in response_json["signatures"][server_name]:
|
|
if key_id not in response_json["verify_keys"]:
|
|
raise ValueError(
|
|
"Key response must include verification keys for all"
|
|
" signatures"
|
|
)
|
|
if key_id in verify_keys:
|
|
verify_signed_json(
|
|
response_json,
|
|
server_name,
|
|
verify_keys[key_id]
|
|
)
|
|
|
|
signed_key_json = sign_json(
|
|
response_json,
|
|
self.config.server_name,
|
|
self.config.signing_key[0],
|
|
)
|
|
|
|
signed_key_json_bytes = encode_canonical_json(signed_key_json)
|
|
ts_valid_until_ms = signed_key_json[u"valid_until_ts"]
|
|
|
|
updated_key_ids = set()
|
|
if requested_id is not None:
|
|
updated_key_ids.add(requested_id)
|
|
updated_key_ids.update(verify_keys)
|
|
updated_key_ids.update(old_verify_keys)
|
|
|
|
response_keys.update(verify_keys)
|
|
response_keys.update(old_verify_keys)
|
|
|
|
for key_id in updated_key_ids:
|
|
yield self.store.store_server_keys_json(
|
|
server_name=server_name,
|
|
key_id=key_id,
|
|
from_server=server_name,
|
|
ts_now_ms=time_now_ms,
|
|
ts_expires_ms=ts_valid_until_ms,
|
|
key_json_bytes=signed_key_json_bytes,
|
|
)
|
|
|
|
defer.returnValue(response_keys)
|
|
|
|
raise ValueError("No verification key found for given key ids")
|
|
|
|
@defer.inlineCallbacks
|
|
def get_server_verify_key_v1_direct(self, server_name, key_ids):
|
|
"""Finds a verification key for the server with one of the key ids.
|
|
Args:
|
|
server_name (str): The name of the server to fetch a key for.
|
|
keys_ids (list of str): The key_ids to check for.
|
|
"""
|
|
|
|
# Try to fetch the key from the remote server.
|
|
|
|
(response, tls_certificate) = yield fetch_server_key(
|
|
server_name, self.hs.tls_context_factory
|
|
)
|
|
|
|
# Check the response.
|
|
|
|
x509_certificate_bytes = crypto.dump_certificate(
|
|
crypto.FILETYPE_ASN1, tls_certificate
|
|
)
|
|
|
|
if ("signatures" not in response
|
|
or server_name not in response["signatures"]):
|
|
raise ValueError("Key response not signed by remote server")
|
|
|
|
if "tls_certificate" not in response:
|
|
raise ValueError("Key response missing TLS certificate")
|
|
|
|
tls_certificate_b64 = response["tls_certificate"]
|
|
|
|
if encode_base64(x509_certificate_bytes) != tls_certificate_b64:
|
|
raise ValueError("TLS certificate doesn't match")
|
|
|
|
# Cache the result in the datastore.
|
|
|
|
time_now_ms = self.clock.time_msec()
|
|
|
|
verify_keys = {}
|
|
for key_id, key_base64 in response["verify_keys"].items():
|
|
if is_signing_algorithm_supported(key_id):
|
|
key_bytes = decode_base64(key_base64)
|
|
verify_key = decode_verify_key_bytes(key_id, key_bytes)
|
|
verify_key.time_added = time_now_ms
|
|
verify_keys[key_id] = verify_key
|
|
|
|
for key_id in response["signatures"][server_name]:
|
|
if key_id not in response["verify_keys"]:
|
|
raise ValueError(
|
|
"Key response must include verification keys for all"
|
|
" signatures"
|
|
)
|
|
if key_id in verify_keys:
|
|
verify_signed_json(
|
|
response,
|
|
server_name,
|
|
verify_keys[key_id]
|
|
)
|
|
|
|
yield self.store.store_server_certificate(
|
|
server_name,
|
|
server_name,
|
|
time_now_ms,
|
|
tls_certificate,
|
|
)
|
|
|
|
yield self.store_keys(
|
|
server_name=server_name,
|
|
from_server=server_name,
|
|
verify_keys=verify_keys,
|
|
)
|
|
|
|
defer.returnValue(verify_keys)
|
|
|
|
@defer.inlineCallbacks
|
|
def store_keys(self, server_name, from_server, verify_keys):
|
|
"""Store a collection of verify keys for a given server
|
|
Args:
|
|
server_name(str): The name of the server the keys are for.
|
|
from_server(str): The server the keys were downloaded from.
|
|
verify_keys(dict): A mapping of key_id to VerifyKey.
|
|
Returns:
|
|
A deferred that completes when the keys are stored.
|
|
"""
|
|
for key_id, key in verify_keys.items():
|
|
# TODO(markjh): Store whether the keys have expired.
|
|
yield self.store.store_server_verify_key(
|
|
server_name, server_name, key.time_added, key
|
|
)
|