diff options
Diffstat (limited to 'synapse/crypto/keyring.py')
| -rw-r--r-- | synapse/crypto/keyring.py | 239 |
1 files changed, 164 insertions, 75 deletions
diff --git a/synapse/crypto/keyring.py b/synapse/crypto/keyring.py index b2f4cea536..0fd15287e7 100644 --- a/synapse/crypto/keyring.py +++ b/synapse/crypto/keyring.py @@ -15,6 +15,7 @@ # limitations under the License. import logging +from collections import defaultdict import six from six import raise_from @@ -45,6 +46,7 @@ from synapse.api.errors import ( ) from synapse.storage.keys import FetchKeyResult from synapse.util import logcontext, unwrapFirstError +from synapse.util.async_helpers import yieldable_gather_results from synapse.util.logcontext import ( LoggingContext, PreserveLoggingContext, @@ -70,6 +72,9 @@ class VerifyKeyRequest(object): json_object(dict): The JSON object to verify. + minimum_valid_until_ts (int): time at which we require the signing key to + be valid. (0 implies we don't care) + deferred(Deferred[str, str, nacl.signing.VerifyKey]): A deferred (server_name, key_id, verify_key) tuple that resolves when a verify key has been fetched. The deferreds' callbacks are run with no @@ -82,7 +87,8 @@ class VerifyKeyRequest(object): server_name = attr.ib() key_ids = attr.ib() json_object = attr.ib() - deferred = attr.ib() + minimum_valid_until_ts = attr.ib() + deferred = attr.ib(default=attr.Factory(defer.Deferred)) class KeyLookupError(ValueError): @@ -90,14 +96,16 @@ class KeyLookupError(ValueError): class Keyring(object): - def __init__(self, hs): + def __init__(self, hs, key_fetchers=None): self.clock = hs.get_clock() - self._key_fetchers = ( - StoreKeyFetcher(hs), - PerspectivesKeyFetcher(hs), - ServerKeyFetcher(hs), - ) + if key_fetchers is None: + key_fetchers = ( + StoreKeyFetcher(hs), + PerspectivesKeyFetcher(hs), + ServerKeyFetcher(hs), + ) + self._key_fetchers = key_fetchers # map from server name to Deferred. Has an entry for each server with # an ongoing key download; the Deferred completes once the download @@ -106,9 +114,25 @@ class Keyring(object): # These are regular, logcontext-agnostic Deferreds. self.key_downloads = {} - def verify_json_for_server(self, server_name, json_object): + def verify_json_for_server(self, server_name, json_object, validity_time): + """Verify that a JSON object has been signed by a given server + + Args: + server_name (str): name of the server which must have signed this object + + json_object (dict): object to be checked + + validity_time (int): timestamp at which we require the signing key to + be valid. (0 implies we don't care) + + Returns: + Deferred[None]: completes if the the object was correctly signed, otherwise + errbacks with an error + """ + req = server_name, json_object, validity_time + return logcontext.make_deferred_yieldable( - self.verify_json_objects_for_server([(server_name, json_object)])[0] + self.verify_json_objects_for_server((req,))[0] ) def verify_json_objects_for_server(self, server_and_json): @@ -116,10 +140,12 @@ class Keyring(object): necessary. Args: - server_and_json (list): List of pairs of (server_name, json_object) + server_and_json (iterable[Tuple[str, dict, int]): + Iterable of triplets of (server_name, json_object, validity_time) + validity_time is a timestamp at which the signing key must be valid. Returns: - List<Deferred>: for each input pair, a deferred indicating success + List<Deferred[None]>: for each input triplet, a deferred indicating success or failure to verify each json object's signature for the given server_name. The deferreds run their callbacks in the sentinel logcontext. @@ -128,12 +154,12 @@ class Keyring(object): verify_requests = [] handle = preserve_fn(_handle_key_deferred) - def process(server_name, json_object): + def process(server_name, json_object, validity_time): """Process an entry in the request list - Given a (server_name, json_object) pair from the request list, - adds a key request to verify_requests, and returns a deferred which will - complete or fail (in the sentinel context) when verification completes. + Given a (server_name, json_object, validity_time) triplet from the request + list, adds a key request to verify_requests, and returns a deferred which + will complete or fail (in the sentinel context) when verification completes. """ key_ids = signature_ids(json_object, server_name) @@ -144,11 +170,16 @@ class Keyring(object): ) ) - logger.debug("Verifying for %s with key_ids %s", server_name, key_ids) + logger.debug( + "Verifying for %s with key_ids %s, min_validity %i", + server_name, + key_ids, + validity_time, + ) # add the key request to the queue, but don't start it off yet. verify_request = VerifyKeyRequest( - server_name, key_ids, json_object, defer.Deferred() + server_name, key_ids, json_object, validity_time ) verify_requests.append(verify_request) @@ -160,8 +191,8 @@ class Keyring(object): return handle(verify_request) results = [ - process(server_name, json_object) - for server_name, json_object in server_and_json + process(server_name, json_object, validity_time) + for server_name, json_object, validity_time in server_and_json ] if verify_requests: @@ -298,8 +329,12 @@ class Keyring(object): verify_request.deferred.errback( SynapseError( 401, - "No key for %s with id %s" - % (verify_request.server_name, verify_request.key_ids), + "No key for %s with ids in %s (min_validity %i)" + % ( + verify_request.server_name, + verify_request.key_ids, + verify_request.minimum_valid_until_ts, + ), Codes.UNAUTHORIZED, ) ) @@ -323,18 +358,28 @@ class Keyring(object): Args: fetcher (KeyFetcher): fetcher to use to fetch the keys remaining_requests (set[VerifyKeyRequest]): outstanding key requests. - Any successfully-completed requests will be reomved from the list. + Any successfully-completed requests will be removed from the list. """ - # dict[str, set(str)]: keys to fetch for each server - missing_keys = {} + # dict[str, dict[str, int]]: keys to fetch. + # server_name -> key_id -> min_valid_ts + missing_keys = defaultdict(dict) + for verify_request in remaining_requests: # any completed requests should already have been removed assert not verify_request.deferred.called - missing_keys.setdefault(verify_request.server_name, set()).update( - verify_request.key_ids - ) + keys_for_server = missing_keys[verify_request.server_name] - results = yield fetcher.get_keys(missing_keys.items()) + for key_id in verify_request.key_ids: + # If we have several requests for the same key, then we only need to + # request that key once, but we should do so with the greatest + # min_valid_until_ts of the requests, so that we can satisfy all of + # the requests. + keys_for_server[key_id] = max( + keys_for_server.get(key_id, -1), + verify_request.minimum_valid_until_ts + ) + + results = yield fetcher.get_keys(missing_keys) completed = list() for verify_request in remaining_requests: @@ -344,25 +389,34 @@ class Keyring(object): # complete this VerifyKeyRequest. result_keys = results.get(server_name, {}) for key_id in verify_request.key_ids: - key = result_keys.get(key_id) - if key: - with PreserveLoggingContext(): - verify_request.deferred.callback( - (server_name, key_id, key.verify_key) - ) - completed.append(verify_request) - break + fetch_key_result = result_keys.get(key_id) + if not fetch_key_result: + # we didn't get a result for this key + continue + + if ( + fetch_key_result.valid_until_ts + < verify_request.minimum_valid_until_ts + ): + # key was not valid at this point + continue + + with PreserveLoggingContext(): + verify_request.deferred.callback( + (server_name, key_id, fetch_key_result.verify_key) + ) + completed.append(verify_request) + break remaining_requests.difference_update(completed) class KeyFetcher(object): - def get_keys(self, server_name_and_key_ids): + def get_keys(self, keys_to_fetch): """ Args: - server_name_and_key_ids (iterable[Tuple[str, iterable[str]]]): - list of (server_name, iterable[key_id]) tuples to fetch keys for - Note that the iterables may be iterated more than once. + keys_to_fetch (dict[str, dict[str, int]]): + the keys to be fetched. server_name -> key_id -> min_valid_ts Returns: Deferred[dict[str, dict[str, synapse.storage.keys.FetchKeyResult|None]]]: @@ -378,13 +432,15 @@ class StoreKeyFetcher(KeyFetcher): self.store = hs.get_datastore() @defer.inlineCallbacks - def get_keys(self, server_name_and_key_ids): + def get_keys(self, keys_to_fetch): """see KeyFetcher.get_keys""" + keys_to_fetch = ( (server_name, key_id) - for server_name, key_ids in server_name_and_key_ids - for key_id in key_ids + for server_name, keys_for_server in keys_to_fetch.items() + for key_id in keys_for_server.keys() ) + res = yield self.store.get_server_verify_keys(keys_to_fetch) keys = {} for (server_name, key_id), key in res.items(): @@ -508,14 +564,14 @@ class PerspectivesKeyFetcher(BaseV2KeyFetcher): self.perspective_servers = self.config.perspectives @defer.inlineCallbacks - def get_keys(self, server_name_and_key_ids): + def get_keys(self, keys_to_fetch): """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 + keys_to_fetch, perspective_name, perspective_keys ) defer.returnValue(result) except KeyLookupError as e: @@ -549,13 +605,15 @@ class PerspectivesKeyFetcher(BaseV2KeyFetcher): @defer.inlineCallbacks def get_server_verify_key_v2_indirect( - self, server_names_and_key_ids, perspective_name, perspective_keys + self, keys_to_fetch, 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 + keys_to_fetch (dict[str, dict[str, int]]): + the keys to be fetched. server_name -> key_id -> min_valid_ts + 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 @@ -569,12 +627,10 @@ class PerspectivesKeyFetcher(BaseV2KeyFetcher): """ logger.info( "Requesting keys %s from notary server %s", - server_names_and_key_ids, + keys_to_fetch.items(), perspective_name, ) - # 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, @@ -582,12 +638,12 @@ class PerspectivesKeyFetcher(BaseV2KeyFetcher): data={ u"server_keys": { server_name: { - key_id: {u"minimum_valid_until_ts": 0} for key_id in key_ids + key_id: {u"minimum_valid_until_ts": min_valid_ts} + for key_id, min_valid_ts in server_keys.items() } - for server_name, key_ids in server_names_and_key_ids + for server_name, server_keys in keys_to_fetch.items() } }, - long_retries=True, ) except (NotRetryingDestination, RequestSendFailed) as e: raise_from(KeyLookupError("Failed to connect to remote server"), e) @@ -693,34 +749,54 @@ class ServerKeyFetcher(BaseV2KeyFetcher): 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) - ) + def get_keys(self, keys_to_fetch): + """ + Args: + keys_to_fetch (dict[str, iterable[str]]): + the keys to be fetched. server_name -> key_ids - merged = {} - for result in results: - merged.update(result) + Returns: + Deferred[dict[str, dict[str, synapse.storage.keys.FetchKeyResult|None]]]: + map from server_name -> key_id -> FetchKeyResult + """ + + results = {} - defer.returnValue( - {server_name: keys for server_name, keys in merged.items() if keys} + @defer.inlineCallbacks + def get_key(key_to_fetch_item): + server_name, key_ids = key_to_fetch_item + try: + keys = yield self.get_server_verify_key_v2_direct(server_name, key_ids) + results[server_name] = keys + except KeyLookupError as e: + logger.warning( + "Error looking up keys %s from %s: %s", key_ids, server_name, e + ) + except Exception: + logger.exception("Error getting keys %s from %s", key_ids, server_name) + + return yieldable_gather_results(get_key, keys_to_fetch.items()).addCallback( + lambda _: results ) @defer.inlineCallbacks def get_server_verify_key_v2_direct(self, server_name, key_ids): + """ + + Args: + server_name (str): + key_ids (iterable[str]): + + Returns: + Deferred[dict[str, FetchKeyResult]]: map from key ID to lookup result + + Raises: + KeyLookupError if there was a problem making the lookup + """ keys = {} # type: dict[str, FetchKeyResult] for requested_key_id in key_ids: + # we may have found this key as a side-effect of asking for another. if requested_key_id in keys: continue @@ -731,6 +807,19 @@ class ServerKeyFetcher(BaseV2KeyFetcher): path="/_matrix/key/v2/server/" + urllib.parse.quote(requested_key_id), ignore_backoff=True, + + # we only give the remote server 10s to respond. It should be an + # easy request to handle, so if it doesn't reply within 10s, it's + # probably not going to. + # + # Furthermore, when we are acting as a notary server, we cannot + # wait all day for all of the origin servers, as the requesting + # server will otherwise time out before we can respond. + # + # (Note that get_json may make 4 attempts, so this can still take + # almost 45 seconds to fetch the headers, plus up to another 60s to + # read the response). + timeout=10000, ) except (NotRetryingDestination, RequestSendFailed) as e: raise_from(KeyLookupError("Failed to connect to remote server"), e) @@ -755,7 +844,7 @@ class ServerKeyFetcher(BaseV2KeyFetcher): ) keys.update(response_keys) - defer.returnValue({server_name: keys}) + defer.returnValue(keys) @defer.inlineCallbacks |