diff options
Diffstat (limited to 'synapse/crypto/keyring.py')
| -rw-r--r-- | synapse/crypto/keyring.py | 405 |
1 files changed, 258 insertions, 147 deletions
diff --git a/synapse/crypto/keyring.py b/synapse/crypto/keyring.py index b2f4cea536..96964b0d50 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, @@ -58,9 +60,9 @@ logger = logging.getLogger(__name__) @attr.s(slots=True, cmp=False) -class VerifyKeyRequest(object): +class VerifyJsonRequest(object): """ - A request for a verify key to verify a JSON object. + A request to verify a JSON object. Attributes: server_name(str): The name of the server to verify against. @@ -70,7 +72,10 @@ class VerifyKeyRequest(object): json_object(dict): The JSON object to verify. - deferred(Deferred[str, str, nacl.signing.VerifyKey]): + minimum_valid_until_ts (int): time at which we require the signing key to + be valid. (0 implies we don't care) + + key_ready (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 logcontext. @@ -80,9 +85,14 @@ class VerifyKeyRequest(object): """ server_name = attr.ib() - key_ids = attr.ib() json_object = attr.ib() - deferred = attr.ib() + minimum_valid_until_ts = attr.ib() + request_name = attr.ib() + key_ids = attr.ib(init=False) + key_ready = attr.ib(default=attr.Factory(defer.Deferred)) + + def __attrs_post_init__(self): + self.key_ids = signature_ids(self.json_object, self.server_name) class KeyLookupError(ValueError): @@ -90,14 +100,16 @@ 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 @@ -106,51 +118,99 @@ class Keyring(object): # These are regular, logcontext-agnostic Deferreds. self.key_downloads = {} - def verify_json_for_server(self, server_name, json_object): - return logcontext.make_deferred_yieldable( - self.verify_json_objects_for_server([(server_name, json_object)])[0] - ) + def verify_json_for_server( + self, server_name, json_object, validity_time, request_name + ): + """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) + + request_name (str): an identifier for this json object (eg, an event id) + for logging. + + Returns: + Deferred[None]: completes if the the object was correctly signed, otherwise + errbacks with an error + """ + req = VerifyJsonRequest(server_name, json_object, validity_time, request_name) + requests = (req,) + return logcontext.make_deferred_yieldable(self._verify_objects(requests)[0]) def verify_json_objects_for_server(self, server_and_json): """Bulk verifies signatures of json objects, bulk fetching keys as necessary. Args: - server_and_json (list): List of pairs of (server_name, json_object) + server_and_json (iterable[Tuple[str, dict, int, str]): + Iterable of (server_name, json_object, validity_time, request_name) + tuples. + + validity_time is a timestamp at which the signing key must be + valid. + + request_name is an identifier for this json object (eg, an event id) + for logging. 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. """ - # a list of VerifyKeyRequests - verify_requests = [] + return self._verify_objects( + VerifyJsonRequest(server_name, json_object, validity_time, request_name) + for server_name, json_object, validity_time, request_name in server_and_json + ) + + def _verify_objects(self, verify_requests): + """Does the work of verify_json_[objects_]for_server + + + Args: + verify_requests (iterable[VerifyJsonRequest]): + Iterable of verification requests. + + Returns: + List<Deferred[None]>: for each input item, 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. + """ + # a list of VerifyJsonRequests which are awaiting a key lookup + key_lookups = [] handle = preserve_fn(_handle_key_deferred) - def process(server_name, json_object): + def process(verify_request): """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. + Adds a key request to key_lookups, and returns a deferred which + will complete or fail (in the sentinel context) when verification completes. """ - key_ids = signature_ids(json_object, server_name) - - if not key_ids: + if not verify_request.key_ids: return defer.fail( SynapseError( - 400, "Not signed by %s" % (server_name,), Codes.UNAUTHORIZED + 400, + "Not signed by %s" % (verify_request.server_name,), + Codes.UNAUTHORIZED, ) ) - logger.debug("Verifying for %s with key_ids %s", server_name, key_ids) + logger.debug( + "Verifying %s for %s with key_ids %s, min_validity %i", + verify_request.request_name, + verify_request.server_name, + verify_request.key_ids, + verify_request.minimum_valid_until_ts, + ) # 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() - ) - verify_requests.append(verify_request) + key_lookups.append(verify_request) # now run _handle_key_deferred, which will wait for the key request # to complete and then do the verification. @@ -159,13 +219,10 @@ class Keyring(object): # wrap it with preserve_fn (aka run_in_background) return handle(verify_request) - results = [ - process(server_name, json_object) - for server_name, json_object in server_and_json - ] + results = [process(r) for r in verify_requests] - if verify_requests: - run_in_background(self._start_key_lookups, verify_requests) + if key_lookups: + run_in_background(self._start_key_lookups, key_lookups) return results @@ -173,10 +230,10 @@ class Keyring(object): def _start_key_lookups(self, verify_requests): """Sets off the key fetches for each verify request - Once each fetch completes, verify_request.deferred will be resolved. + Once each fetch completes, verify_request.key_ready will be resolved. Args: - verify_requests (List[VerifyKeyRequest]): + verify_requests (List[VerifyJsonRequest]): """ try: @@ -219,7 +276,7 @@ class Keyring(object): return res for verify_request in verify_requests: - verify_request.deferred.addBoth(remove_deferreds, verify_request) + verify_request.key_ready.addBoth(remove_deferreds, verify_request) except Exception: logger.exception("Error starting key lookups") @@ -272,16 +329,16 @@ class Keyring(object): def _get_server_verify_keys(self, verify_requests): """Tries to find at least one key for each verify request - For each verify_request, verify_request.deferred is called back with + For each verify_request, verify_request.key_ready is called back with params (server_name, key_id, VerifyKey) if a key is found, or errbacked with a SynapseError if none of the keys are found. Args: - verify_requests (list[VerifyKeyRequest]): list of verify requests + verify_requests (list[VerifyJsonRequest]): list of verify requests """ remaining_requests = set( - (rq for rq in verify_requests if not rq.deferred.called) + (rq for rq in verify_requests if not rq.key_ready.called) ) @defer.inlineCallbacks @@ -295,11 +352,15 @@ class Keyring(object): # look for any requests which weren't satisfied with PreserveLoggingContext(): for verify_request in remaining_requests: - verify_request.deferred.errback( + verify_request.key_ready.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, ) ) @@ -311,8 +372,8 @@ class Keyring(object): logger.error("Unexpected error in _get_server_verify_keys: %s", err) with PreserveLoggingContext(): for verify_request in remaining_requests: - if not verify_request.deferred.called: - verify_request.deferred.errback(err) + if not verify_request.key_ready.called: + verify_request.key_ready.errback(err) run_in_background(do_iterations).addErrback(on_err) @@ -322,47 +383,66 @@ 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. + remaining_requests (set[VerifyJsonRequest]): outstanding key requests. + 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 - ) + assert not verify_request.key_ready.called + keys_for_server = missing_keys[verify_request.server_name] + + 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.items()) + results = yield fetcher.get_keys(missing_keys) completed = list() for verify_request in remaining_requests: server_name = verify_request.server_name # see if any of the keys we got this time are sufficient to - # complete this VerifyKeyRequest. + # complete this VerifyJsonRequest. 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.key_ready.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 +458,15 @@ 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(): @@ -398,9 +480,7 @@ class BaseV2KeyFetcher(object): self.config = hs.get_config() @defer.inlineCallbacks - def process_v2_response( - self, from_server, response_json, time_added_ms - ): + def process_v2_response(self, from_server, response_json, time_added_ms): """Parse a 'Server Keys' structure from the result of a /key request This is used to parse either the entirety of the response from @@ -505,25 +585,27 @@ class PerspectivesKeyFetcher(BaseV2KeyFetcher): super(PerspectivesKeyFetcher, self).__init__(hs) self.clock = hs.get_clock() self.client = hs.get_http_client() - self.perspective_servers = self.config.perspectives + self.key_servers = self.config.key_servers @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): + def get_key(key_server): try: result = yield self.get_server_verify_key_v2_indirect( - server_name_and_key_ids, perspective_name, perspective_keys + keys_to_fetch, key_server ) defer.returnValue(result) except KeyLookupError as e: - logger.warning("Key lookup failed from %r: %s", perspective_name, e) + logger.warning( + "Key lookup failed from %r: %s", key_server.server_name, e + ) except Exception as e: logger.exception( "Unable to get key from %r: %s %s", - perspective_name, + key_server.server_name, type(e).__name__, str(e), ) @@ -533,8 +615,8 @@ class PerspectivesKeyFetcher(BaseV2KeyFetcher): 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() + run_in_background(get_key, server) + for server in self.key_servers ], consumeErrors=True, ).addErrback(unwrapFirstError) @@ -549,15 +631,15 @@ 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, key_server ): """ 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 + keys_to_fetch (dict[str, dict[str, int]]): + the keys to be fetched. server_name -> key_id -> min_valid_ts + + key_server (synapse.config.key.TrustedKeyServer): notary server to query for + the keys Returns: Deferred[dict[str, dict[str, synapse.storage.keys.FetchKeyResult]]]: map @@ -567,14 +649,13 @@ class PerspectivesKeyFetcher(BaseV2KeyFetcher): KeyLookupError if there was an error processing the entire response from the server """ + perspective_name = key_server.server_name 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 +663,12 @@ 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) @@ -609,11 +690,13 @@ class PerspectivesKeyFetcher(BaseV2KeyFetcher): ) try: - processed_response = yield self._process_perspectives_response( - perspective_name, - perspective_keys, + self._validate_perspectives_response( + key_server, response, - time_added_ms=time_now_ms, + ) + + processed_response = yield self.process_v2_response( + perspective_name, response, time_added_ms=time_now_ms ) except KeyLookupError as e: logger.warning( @@ -637,28 +720,24 @@ class PerspectivesKeyFetcher(BaseV2KeyFetcher): defer.returnValue(keys) - def _process_perspectives_response( - self, perspective_name, perspective_keys, response, time_added_ms + def _validate_perspectives_response( + self, key_server, response, ): - """Parse a 'Server Keys' structure from the result of a /key/query request - - Checks that the entry is correctly signed by the perspectives server, and then - passes over to process_v2_response + """Optionally check the signature on the result of a /key/query request Args: - perspective_name (str): the name of the notary server that produced this - result - - perspective_keys (dict[str, VerifyKey]): map of key_id->key for the - notary server + key_server (synapse.config.key.TrustedKeyServer): the notary server that + produced this result response (dict): the json-decoded Server Keys response object + """ + perspective_name = key_server.server_name + perspective_keys = key_server.verify_keys - time_added_ms (int): the timestamp to record in server_keys_json + if perspective_keys is None: + # signature checking is disabled on this server + return - Returns: - Deferred[dict[str, FetchKeyResult]]: map from key_id to result object - """ if ( u"signatures" not in response or perspective_name not in response[u"signatures"] @@ -671,6 +750,13 @@ class PerspectivesKeyFetcher(BaseV2KeyFetcher): verify_signed_json(response, perspective_name, perspective_keys[key_id]) verified = True + if perspective_name == "matrix.org" and key_id == "ed25519:auto": + logger.warning( + "Trusting trusted_key_server responses signed by the " + "compromised matrix.org signing key 'ed25519:auto'. " + "This is a placebo." + ) + if not verified: raise KeyLookupError( "Response not signed with a known key: signed with: %r, known keys: %r" @@ -680,10 +766,6 @@ class PerspectivesKeyFetcher(BaseV2KeyFetcher): ) ) - return self.process_v2_response( - perspective_name, response, time_added_ms=time_added_ms - ) - class ServerKeyFetcher(BaseV2KeyFetcher): """KeyFetcher impl which fetches keys from the origin servers""" @@ -693,34 +775,54 @@ 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.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) - defer.returnValue( - {server_name: keys for server_name, keys in merged.items() if keys} + 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 +833,19 @@ 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 +870,7 @@ class ServerKeyFetcher(BaseV2KeyFetcher): ) keys.update(response_keys) - defer.returnValue({server_name: keys}) + defer.returnValue(keys) @defer.inlineCallbacks @@ -763,7 +878,7 @@ def _handle_key_deferred(verify_request): """Waits for the key to become available, and then performs a verification Args: - verify_request (VerifyKeyRequest): + verify_request (VerifyJsonRequest): Returns: Deferred[None] @@ -773,14 +888,10 @@ def _handle_key_deferred(verify_request): """ server_name = verify_request.server_name with PreserveLoggingContext(): - _, key_id, verify_key = yield verify_request.deferred + _, key_id, verify_key = yield verify_request.key_ready json_object = verify_request.json_object - logger.debug( - "Got key %s %s:%s for server %s, verifying" - % (key_id, verify_key.alg, verify_key.version, server_name) - ) try: verify_signed_json(json_object, server_name, verify_key) except SignatureVerifyException as e: |