From a6f7f845702c56dd7d1e7dfabd3f50a71f245cc1 Mon Sep 17 00:00:00 2001 From: Richard van der Hoff <1389908+richvdh@users.noreply.github.com> Date: Fri, 19 Nov 2021 10:55:09 +0000 Subject: Fix verification of objects signed with old local keys (#11379) Fixes a bug introduced in #11129: objects signed by the local server, but with keys other than the current one, could not be successfully verified. We need to check the key id in the signature, and track down the right key. --- synapse/crypto/keyring.py | 69 ++++++++++++++++++++++++++++------------------- 1 file changed, 41 insertions(+), 28 deletions(-) (limited to 'synapse/crypto/keyring.py') diff --git a/synapse/crypto/keyring.py b/synapse/crypto/keyring.py index f641ab7ef5..4cda439ad9 100644 --- a/synapse/crypto/keyring.py +++ b/synapse/crypto/keyring.py @@ -1,5 +1,4 @@ -# Copyright 2014-2016 OpenMarket Ltd -# Copyright 2017, 2018 New Vector Ltd +# Copyright 2014-2021 The Matrix.org Foundation C.I.C. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. @@ -120,16 +119,6 @@ class VerifyJsonRequest: key_ids=key_ids, ) - def to_fetch_key_request(self) -> "_FetchKeyRequest": - """Create a key fetch request for all keys needed to satisfy the - verification request. - """ - return _FetchKeyRequest( - server_name=self.server_name, - minimum_valid_until_ts=self.minimum_valid_until_ts, - key_ids=self.key_ids, - ) - class KeyLookupError(ValueError): pass @@ -179,8 +168,22 @@ class Keyring: clock=hs.get_clock(), process_batch_callback=self._inner_fetch_key_requests, ) - self.verify_key = get_verify_key(hs.signing_key) - self.hostname = hs.hostname + + self._hostname = hs.hostname + + # build a FetchKeyResult for each of our own keys, to shortcircuit the + # fetcher. + self._local_verify_keys: Dict[str, FetchKeyResult] = {} + for key_id, key in hs.config.key.old_signing_keys.items(): + self._local_verify_keys[key_id] = FetchKeyResult( + verify_key=key, valid_until_ts=key.expired_ts + ) + + vk = get_verify_key(hs.signing_key) + self._local_verify_keys[f"{vk.alg}:{vk.version}"] = FetchKeyResult( + verify_key=vk, + valid_until_ts=2 ** 63, # fake future timestamp + ) async def verify_json_for_server( self, @@ -267,22 +270,32 @@ class Keyring: Codes.UNAUTHORIZED, ) - # If we are the originating server don't fetch verify key for self over federation - if verify_request.server_name == self.hostname: - await self._process_json(self.verify_key, verify_request) - return + found_keys: Dict[str, FetchKeyResult] = {} - # Add the keys we need to verify to the queue for retrieval. We queue - # up requests for the same server so we don't end up with many in flight - # requests for the same keys. - key_request = verify_request.to_fetch_key_request() - found_keys_by_server = await self._server_queue.add_to_queue( - key_request, key=verify_request.server_name - ) + # If we are the originating server, short-circuit the key-fetch for any keys + # we already have + if verify_request.server_name == self._hostname: + for key_id in verify_request.key_ids: + if key_id in self._local_verify_keys: + found_keys[key_id] = self._local_verify_keys[key_id] + + key_ids_to_find = set(verify_request.key_ids) - found_keys.keys() + if key_ids_to_find: + # Add the keys we need to verify to the queue for retrieval. We queue + # up requests for the same server so we don't end up with many in flight + # requests for the same keys. + key_request = _FetchKeyRequest( + server_name=verify_request.server_name, + minimum_valid_until_ts=verify_request.minimum_valid_until_ts, + key_ids=list(key_ids_to_find), + ) + found_keys_by_server = await self._server_queue.add_to_queue( + key_request, key=verify_request.server_name + ) - # Since we batch up requests the returned set of keys may contain keys - # from other servers, so we pull out only the ones we care about.s - found_keys = found_keys_by_server.get(verify_request.server_name, {}) + # Since we batch up requests the returned set of keys may contain keys + # from other servers, so we pull out only the ones we care about. + found_keys.update(found_keys_by_server.get(verify_request.server_name, {})) # Verify each signature we got valid keys for, raising if we can't # verify any of them. -- cgit 1.5.1 From 9cd13c5f63d6cdcb46dcbe4e103d3b5c12f1ce9d Mon Sep 17 00:00:00 2001 From: Richard van der Hoff <1389908+richvdh@users.noreply.github.com> Date: Mon, 29 Nov 2021 13:15:36 +0000 Subject: Fix perspectives requests for multiple keys for the same server (#11440) If we tried to request multiple keys for the same server, we would end up dropping some of those requests. --- changelog.d/11440.bugfix | 1 + synapse/crypto/keyring.py | 30 ++++++++++++------- tests/crypto/test_keyring.py | 71 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 91 insertions(+), 11 deletions(-) create mode 100644 changelog.d/11440.bugfix (limited to 'synapse/crypto/keyring.py') diff --git a/changelog.d/11440.bugfix b/changelog.d/11440.bugfix new file mode 100644 index 0000000000..02ce2e428f --- /dev/null +++ b/changelog.d/11440.bugfix @@ -0,0 +1 @@ +Fix a bug introduced in Synapse 1.36 which could cause problems fetching event-signing keys from trusted key servers. diff --git a/synapse/crypto/keyring.py b/synapse/crypto/keyring.py index 4cda439ad9..993b04099e 100644 --- a/synapse/crypto/keyring.py +++ b/synapse/crypto/keyring.py @@ -667,21 +667,25 @@ class PerspectivesKeyFetcher(BaseV2KeyFetcher): perspective_name, ) + request: JsonDict = {} + for queue_value in keys_to_fetch: + # there may be multiple requests for each server, so we have to merge + # them intelligently. + request_for_server = { + key_id: { + "minimum_valid_until_ts": queue_value.minimum_valid_until_ts, + } + for key_id in queue_value.key_ids + } + request.setdefault(queue_value.server_name, {}).update(request_for_server) + + logger.debug("Request to notary server %s: %s", perspective_name, request) + try: query_response = await self.client.post_json( destination=perspective_name, path="/_matrix/key/v2/query", - data={ - "server_keys": { - queue_value.server_name: { - key_id: { - "minimum_valid_until_ts": queue_value.minimum_valid_until_ts, - } - for key_id in queue_value.key_ids - } - for queue_value in keys_to_fetch - } - }, + data={"server_keys": request}, ) except (NotRetryingDestination, RequestSendFailed) as e: # these both have str() representations which we can't really improve upon @@ -689,6 +693,10 @@ class PerspectivesKeyFetcher(BaseV2KeyFetcher): except HttpResponseException as e: raise KeyLookupError("Remote server returned an error: %s" % (e,)) + logger.debug( + "Response from notary server %s: %s", perspective_name, query_response + ) + keys: Dict[str, Dict[str, FetchKeyResult]] = {} added_keys: List[Tuple[str, str, FetchKeyResult]] = [] diff --git a/tests/crypto/test_keyring.py b/tests/crypto/test_keyring.py index 4d1e154578..17a9fb63a1 100644 --- a/tests/crypto/test_keyring.py +++ b/tests/crypto/test_keyring.py @@ -22,6 +22,7 @@ import signedjson.sign from nacl.signing import SigningKey from signedjson.key import encode_verify_key_base64, get_verify_key +from twisted.internet import defer from twisted.internet.defer import Deferred, ensureDeferred from synapse.api.errors import SynapseError @@ -577,6 +578,76 @@ class PerspectivesKeyFetcherTestCase(unittest.HomeserverTestCase): bytes(res["key_json"]), canonicaljson.encode_canonical_json(response) ) + def test_get_multiple_keys_from_perspectives(self): + """Check that we can correctly request multiple keys for the same server""" + + fetcher = PerspectivesKeyFetcher(self.hs) + + SERVER_NAME = "server2" + + testkey1 = signedjson.key.generate_signing_key("ver1") + testverifykey1 = signedjson.key.get_verify_key(testkey1) + testverifykey1_id = "ed25519:ver1" + + testkey2 = signedjson.key.generate_signing_key("ver2") + testverifykey2 = signedjson.key.get_verify_key(testkey2) + testverifykey2_id = "ed25519:ver2" + + VALID_UNTIL_TS = 200 * 1000 + + response1 = self.build_perspectives_response( + SERVER_NAME, + testkey1, + VALID_UNTIL_TS, + ) + response2 = self.build_perspectives_response( + SERVER_NAME, + testkey2, + VALID_UNTIL_TS, + ) + + async def post_json(destination, path, data, **kwargs): + self.assertEqual(destination, self.mock_perspective_server.server_name) + self.assertEqual(path, "/_matrix/key/v2/query") + + # check that the request is for the expected keys + q = data["server_keys"] + + self.assertEqual( + list(q[SERVER_NAME].keys()), [testverifykey1_id, testverifykey2_id] + ) + return {"server_keys": [response1, response2]} + + self.http_client.post_json.side_effect = post_json + + # fire off two separate requests; they should get merged together into a + # single HTTP hit. + request1_d = defer.ensureDeferred( + fetcher.get_keys(SERVER_NAME, [testverifykey1_id], 0) + ) + request2_d = defer.ensureDeferred( + fetcher.get_keys(SERVER_NAME, [testverifykey2_id], 0) + ) + + keys1 = self.get_success(request1_d) + self.assertIn(testverifykey1_id, keys1) + k = keys1[testverifykey1_id] + self.assertEqual(k.valid_until_ts, VALID_UNTIL_TS) + self.assertEqual(k.verify_key, testverifykey1) + self.assertEqual(k.verify_key.alg, "ed25519") + self.assertEqual(k.verify_key.version, "ver1") + + keys2 = self.get_success(request2_d) + self.assertIn(testverifykey2_id, keys2) + k = keys2[testverifykey2_id] + self.assertEqual(k.valid_until_ts, VALID_UNTIL_TS) + self.assertEqual(k.verify_key, testverifykey2) + self.assertEqual(k.verify_key.alg, "ed25519") + self.assertEqual(k.verify_key.version, "ver2") + + # finally, ensure that only one request was sent + self.assertEqual(self.http_client.post_json.call_count, 1) + def test_get_perspectives_own_key(self): """Check that we can get the perspectives server's own keys -- cgit 1.5.1