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Factor out KeyFetchers from KeyRing 

Rather than have three methods which have to have the same interface,
factor out a separate interface which is provided by three implementations.

I find it easier to grok the code this way.
This commit is contained in:
Richard van der Hoff 2019-04-09 18:28:17 +01:00
parent b75537beaf
commit 895b79ac2e
3 changed files with 276 additions and 218 deletions
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1
changelog.d/5244.misc Normal file
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@ -0,0 +1 @@
Refactor synapse.crypto.keyring to use a KeyFetcher interface.

459
synapse/crypto/keyring.py
View File

@ -80,12 +80,13 @@ class KeyLookupError(ValueError):
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_fetchers = (
StoreKeyFetcher(hs),
PerspectivesKeyFetcher(hs),
ServerKeyFetcher(hs),
)
# map from server name to Deferred. Has an entry for each server with
# an ongoing key download; the Deferred completes once the download
@ -271,13 +272,6 @@ class Keyring(object):
verify_requests (list[VerifyKeyRequest]): list of verify requests
"""
# These are functions that produce keys given a list of key ids
key_fetch_fns = (
self.get_keys_from_store, # First try the local store
self.get_keys_from_perspectives, # Then try via perspectives
self.get_keys_from_server, # Then try directly
)
@defer.inlineCallbacks
def do_iterations():
with Measure(self.clock, "get_server_verify_keys"):
@ -288,8 +282,8 @@ class Keyring(object):
verify_request.key_ids
)
for fn in key_fetch_fns:
results = yield fn(missing_keys.items())
for f in self._key_fetchers:
results = yield f.get_keys(missing_keys.items())
# We now need to figure out which verify requests we have keys
# for and which we don't
@ -348,8 +342,9 @@ class Keyring(object):
run_in_background(do_iterations).addErrback(on_err)
@defer.inlineCallbacks
def get_keys_from_store(self, server_name_and_key_ids):
class KeyFetcher(object):
def get_keys(self, server_name_and_key_ids):
"""
Args:
server_name_and_key_ids (iterable[Tuple[str, iterable[str]]]):
@ -359,6 +354,18 @@ class Keyring(object):
Deferred[dict[str, dict[str, synapse.storage.keys.FetchKeyResult|None]]]:
map from server_name -> key_id -> FetchKeyResult
"""
raise NotImplementedError
class StoreKeyFetcher(KeyFetcher):
"""KeyFetcher impl which fetches keys from our data store"""
def __init__(self, hs):
self.store = hs.get_datastore()
@defer.inlineCallbacks
def get_keys(self, server_name_and_key_ids):
"""see KeyFetcher.get_keys"""
keys_to_fetch = (
(server_name, key_id)
for server_name, key_ids in server_name_and_key_ids
@ -370,203 +377,11 @@ class Keyring(object):
keys.setdefault(server_name, {})[key_id] = key
defer.returnValue(keys)
@defer.inlineCallbacks
def get_keys_from_perspectives(self, server_name_and_key_ids):
@defer.inlineCallbacks
def get_key(perspective_name, perspective_keys):
try:
result = yield self.get_server_verify_key_v2_indirect(
server_name_and_key_ids, perspective_name, perspective_keys
)
defer.returnValue(result)
except KeyLookupError as e:
logger.warning("Key lookup failed from %r: %s", perspective_name, e)
except Exception as e:
logger.exception(
"Unable to get key from %r: %s %s",
perspective_name,
type(e).__name__,
str(e),
)
defer.returnValue({})
results = yield logcontext.make_deferred_yieldable(
defer.gatherResults(
[
run_in_background(get_key, p_name, p_keys)
for p_name, p_keys in self.perspective_servers.items()
],
consumeErrors=True,
).addErrback(unwrapFirstError)
)
union_of_keys = {}
for result in results:
for server_name, keys in result.items():
union_of_keys.setdefault(server_name, {}).update(keys)
defer.returnValue(union_of_keys)
@defer.inlineCallbacks
def get_keys_from_server(self, server_name_and_key_ids):
results = yield logcontext.make_deferred_yieldable(
defer.gatherResults(
[
run_in_background(
self.get_server_verify_key_v2_direct, server_name, key_ids
)
for server_name, key_ids in server_name_and_key_ids
],
consumeErrors=True,
).addErrback(unwrapFirstError)
)
merged = {}
for result in results:
merged.update(result)
defer.returnValue(
{server_name: keys for server_name, keys in merged.items() if keys}
)
@defer.inlineCallbacks
def get_server_verify_key_v2_indirect(
self, server_names_and_key_ids, perspective_name, perspective_keys
):
"""
Args:
server_names_and_key_ids (iterable[Tuple[str, iterable[str]]]):
list of (server_name, iterable[key_id]) tuples to fetch keys for
perspective_name (str): name of the notary server to query for the keys
perspective_keys (dict[str, VerifyKey]): map of key_id->key for the
notary server
Returns:
Deferred[dict[str, dict[str, synapse.storage.keys.FetchKeyResult]]]: map
from server_name -> key_id -> FetchKeyResult
"""
# 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.
try:
query_response = yield self.client.post_json(
destination=perspective_name,
path="/_matrix/key/v2/query",
data={
u"server_keys": {
server_name: {
key_id: {u"minimum_valid_until_ts": 0} for key_id in key_ids
}
for server_name, key_ids in server_names_and_key_ids
}
},
long_retries=True,
)
except (NotRetryingDestination, RequestSendFailed) as e:
raise_from(KeyLookupError("Failed to connect to remote server"), e)
except HttpResponseException as e:
raise_from(KeyLookupError("Remote server returned an error"), e)
keys = {}
added_keys = []
time_now_ms = self.clock.time_msec()
for response in query_response["server_keys"]:
if (
u"signatures" not in response
or perspective_name not in response[u"signatures"]
):
raise KeyLookupError(
"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 KeyLookupError(
"Response not signed with a known key for perspective"
" server %r" % (perspective_name,)
)
processed_response = yield self.process_v2_response(
perspective_name, response, time_added_ms=time_now_ms
)
server_name = response["server_name"]
added_keys.extend(
(server_name, key_id, key) for key_id, key in processed_response.items()
)
keys.setdefault(server_name, {}).update(processed_response)
yield self.store.store_server_verify_keys(
perspective_name, time_now_ms, added_keys
)
defer.returnValue(keys)
@defer.inlineCallbacks
def get_server_verify_key_v2_direct(self, server_name, key_ids):
keys = {} # type: dict[str, FetchKeyResult]
for requested_key_id in key_ids:
if requested_key_id in keys:
continue
time_now_ms = self.clock.time_msec()
try:
response = yield self.client.get_json(
destination=server_name,
path="/_matrix/key/v2/server/"
+ urllib.parse.quote(requested_key_id),
ignore_backoff=True,
)
except (NotRetryingDestination, RequestSendFailed) as e:
raise_from(KeyLookupError("Failed to connect to remote server"), e)
except HttpResponseException as e:
raise_from(KeyLookupError("Remote server returned an error"), e)
if (
u"signatures" not in response
or server_name not in response[u"signatures"]
):
raise KeyLookupError("Key response not signed by remote server")
if response["server_name"] != server_name:
raise KeyLookupError(
"Expected a response for server %r not %r"
% (server_name, response["server_name"])
)
response_keys = yield self.process_v2_response(
from_server=server_name,
requested_ids=[requested_key_id],
response_json=response,
time_added_ms=time_now_ms,
)
yield self.store.store_server_verify_keys(
server_name,
time_now_ms,
((server_name, key_id, key) for key_id, key in response_keys.items()),
)
keys.update(response_keys)
defer.returnValue({server_name: keys})
class BaseV2KeyFetcher(object):
def __init__(self, hs):
self.store = hs.get_datastore()
self.config = hs.get_config()
@defer.inlineCallbacks
def process_v2_response(
@ -670,6 +485,226 @@ class Keyring(object):
defer.returnValue(verify_keys)
class PerspectivesKeyFetcher(BaseV2KeyFetcher):
"""KeyFetcher impl which fetches keys from the "perspectives" servers"""
def __init__(self, hs):
super(PerspectivesKeyFetcher, self).__init__(hs)
self.clock = hs.get_clock()
self.client = hs.get_http_client()
self.perspective_servers = self.config.perspectives
@defer.inlineCallbacks
def get_keys(self, server_name_and_key_ids):
"""see KeyFetcher.get_keys"""
@defer.inlineCallbacks
def get_key(perspective_name, perspective_keys):
try:
result = yield self.get_server_verify_key_v2_indirect(
server_name_and_key_ids, perspective_name, perspective_keys
)
defer.returnValue(result)
except KeyLookupError as e:
logger.warning("Key lookup failed from %r: %s", perspective_name, e)
except Exception as e:
logger.exception(
"Unable to get key from %r: %s %s",
perspective_name,
type(e).__name__,
str(e),
)
defer.returnValue({})
results = yield logcontext.make_deferred_yieldable(
defer.gatherResults(
[
run_in_background(get_key, p_name, p_keys)
for p_name, p_keys in self.perspective_servers.items()
],
consumeErrors=True,
).addErrback(unwrapFirstError)
)
union_of_keys = {}
for result in results:
for server_name, keys in result.items():
union_of_keys.setdefault(server_name, {}).update(keys)
defer.returnValue(union_of_keys)
@defer.inlineCallbacks
def get_server_verify_key_v2_indirect(
self, server_names_and_key_ids, perspective_name, perspective_keys
):
"""
Args:
server_names_and_key_ids (iterable[Tuple[str, iterable[str]]]):
list of (server_name, iterable[key_id]) tuples to fetch keys for
perspective_name (str): name of the notary server to query for the keys
perspective_keys (dict[str, VerifyKey]): map of key_id->key for the
notary server
Returns:
Deferred[dict[str, dict[str, synapse.storage.keys.FetchKeyResult]]]: map
from server_name -> key_id -> FetchKeyResult
"""
# 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.
try:
query_response = yield self.client.post_json(
destination=perspective_name,
path="/_matrix/key/v2/query",
data={
u"server_keys": {
server_name: {
key_id: {u"minimum_valid_until_ts": 0} for key_id in key_ids
}
for server_name, key_ids in server_names_and_key_ids
}
},
long_retries=True,
)
except (NotRetryingDestination, RequestSendFailed) as e:
raise_from(KeyLookupError("Failed to connect to remote server"), e)
except HttpResponseException as e:
raise_from(KeyLookupError("Remote server returned an error"), e)
keys = {}
added_keys = []
time_now_ms = self.clock.time_msec()
for response in query_response["server_keys"]:
if (
u"signatures" not in response
or perspective_name not in response[u"signatures"]
):
raise KeyLookupError(
"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 KeyLookupError(
"Response not signed with a known key for perspective"
" server %r" % (perspective_name,)
)
processed_response = yield self.process_v2_response(
perspective_name, response, time_added_ms=time_now_ms
)
server_name = response["server_name"]
added_keys.extend(
(server_name, key_id, key) for key_id, key in processed_response.items()
)
keys.setdefault(server_name, {}).update(processed_response)
yield self.store.store_server_verify_keys(
perspective_name, time_now_ms, added_keys
)
defer.returnValue(keys)
class ServerKeyFetcher(BaseV2KeyFetcher):
"""KeyFetcher impl which fetches keys from the origin servers"""
def __init__(self, hs):
super(ServerKeyFetcher, self).__init__(hs)
self.clock = hs.get_clock()
self.client = hs.get_http_client()
@defer.inlineCallbacks
def get_keys(self, server_name_and_key_ids):
"""see KeyFetcher.get_keys"""
results = yield logcontext.make_deferred_yieldable(
defer.gatherResults(
[
run_in_background(
self.get_server_verify_key_v2_direct, server_name, key_ids
)
for server_name, key_ids in server_name_and_key_ids
],
consumeErrors=True,
).addErrback(unwrapFirstError)
)
merged = {}
for result in results:
merged.update(result)
defer.returnValue(
{server_name: keys for server_name, keys in merged.items() if keys}
)
@defer.inlineCallbacks
def get_server_verify_key_v2_direct(self, server_name, key_ids):
keys = {} # type: dict[str, FetchKeyResult]
for requested_key_id in key_ids:
if requested_key_id in keys:
continue
time_now_ms = self.clock.time_msec()
try:
response = yield self.client.get_json(
destination=server_name,
path="/_matrix/key/v2/server/"
+ urllib.parse.quote(requested_key_id),
ignore_backoff=True,
)
except (NotRetryingDestination, RequestSendFailed) as e:
raise_from(KeyLookupError("Failed to connect to remote server"), e)
except HttpResponseException as e:
raise_from(KeyLookupError("Remote server returned an error"), e)
if (
u"signatures" not in response
or server_name not in response[u"signatures"]
):
raise KeyLookupError("Key response not signed by remote server")
if response["server_name"] != server_name:
raise KeyLookupError(
"Expected a response for server %r not %r"
% (server_name, response["server_name"])
)
response_keys = yield self.process_v2_response(
from_server=server_name,
requested_ids=[requested_key_id],
response_json=response,
time_added_ms=time_now_ms,
)
yield self.store.store_server_verify_keys(
server_name,
time_now_ms,
((server_name, key_id, key) for key_id, key in response_keys.items()),
)
keys.update(response_keys)
defer.returnValue({server_name: keys})
@defer.inlineCallbacks
def _handle_key_deferred(verify_request):
"""Waits for the key to become available, and then performs a verification

34
tests/crypto/test_keyring.py
View File

@ -24,7 +24,11 @@ from twisted.internet import defer
from synapse.api.errors import SynapseError
from synapse.crypto import keyring
from synapse.crypto.keyring import KeyLookupError
from synapse.crypto.keyring import (
KeyLookupError,
PerspectivesKeyFetcher,
ServerKeyFetcher,
)
from synapse.storage.keys import FetchKeyResult
from synapse.util import logcontext
from synapse.util.logcontext import LoggingContext
@ -218,12 +222,19 @@ class KeyringTestCase(unittest.HomeserverTestCase):
self.assertFalse(d.called)
self.get_success(d)
class ServerKeyFetcherTestCase(unittest.HomeserverTestCase):
def make_homeserver(self, reactor, clock):
self.http_client = Mock()
hs = self.setup_test_homeserver(handlers=None, http_client=self.http_client)
return hs
def test_get_keys_from_server(self):
# arbitrarily advance the clock a bit
self.reactor.advance(100)
SERVER_NAME = "server2"
kr = keyring.Keyring(self.hs)
fetcher = ServerKeyFetcher(self.hs)
testkey = signedjson.key.generate_signing_key("ver1")
testverifykey = signedjson.key.get_verify_key(testkey)
testverifykey_id = "ed25519:ver1"
@ -250,7 +261,7 @@ class KeyringTestCase(unittest.HomeserverTestCase):
self.http_client.get_json.side_effect = get_json
server_name_and_key_ids = [(SERVER_NAME, ("key1",))]
keys = self.get_success(kr.get_keys_from_server(server_name_and_key_ids))
keys = self.get_success(fetcher.get_keys(server_name_and_key_ids))
k = keys[SERVER_NAME][testverifykey_id]
self.assertEqual(k.valid_until_ts, VALID_UNTIL_TS)
self.assertEqual(k.verify_key, testverifykey)
@ -278,15 +289,26 @@ class KeyringTestCase(unittest.HomeserverTestCase):
# change the server name: it should cause a rejection
response["server_name"] = "OTHER_SERVER"
self.get_failure(
kr.get_keys_from_server(server_name_and_key_ids), KeyLookupError
fetcher.get_keys(server_name_and_key_ids), KeyLookupError
)
class PerspectivesKeyFetcherTestCase(unittest.HomeserverTestCase):
def make_homeserver(self, reactor, clock):
self.mock_perspective_server = MockPerspectiveServer()
self.http_client = Mock()
hs = self.setup_test_homeserver(handlers=None, http_client=self.http_client)
keys = self.mock_perspective_server.get_verify_keys()
hs.config.perspectives = {self.mock_perspective_server.server_name: keys}
return hs
def test_get_keys_from_perspectives(self):
# arbitrarily advance the clock a bit
self.reactor.advance(100)
fetcher = PerspectivesKeyFetcher(self.hs)
SERVER_NAME = "server2"
kr = keyring.Keyring(self.hs)
testkey = signedjson.key.generate_signing_key("ver1")
testverifykey = signedjson.key.get_verify_key(testkey)
testverifykey_id = "ed25519:ver1"
@ -320,7 +342,7 @@ class KeyringTestCase(unittest.HomeserverTestCase):
self.http_client.post_json.side_effect = post_json
server_name_and_key_ids = [(SERVER_NAME, ("key1",))]
keys = self.get_success(kr.get_keys_from_perspectives(server_name_and_key_ids))
keys = self.get_success(fetcher.get_keys(server_name_and_key_ids))
self.assertIn(SERVER_NAME, keys)
k = keys[SERVER_NAME][testverifykey_id]
self.assertEqual(k.valid_until_ts, VALID_UNTIL_TS)