Merge pull request #5001 from matrix-org/rav/keyring_cleanups

Cleanups in the Keyring

4 files changed, 181 insertions, 33 deletions

diff --git a/changelog.d/5001.misc b/changelog.d/5001.misc
new file mode 100644
index 0000000000..bf590a016d
--- /dev/null
+++ b/changelog.d/5001.misc
@@ -0,0 +1 @@
+Clean up some code in the server-key Keyring.
\ No newline at end of file
diff --git a/synapse/crypto/keyring.py b/synapse/crypto/keyring.py
index 0207cd989a..54af60d711 100644
--- a/synapse/crypto/keyring.py
+++ b/synapse/crypto/keyring.py
@@ -20,6 +20,7 @@ from collections import namedtuple
 from six import raise_from
 from six.moves import urllib
 
+import nacl.signing
 from signedjson.key import (
     decode_verify_key_bytes,
     encode_verify_key_base64,
@@ -494,11 +495,11 @@ class Keyring(object):
                 )
 
             processed_response = yield self.process_v2_response(
-                perspective_name, response, only_from_server=False
+                perspective_name, response
             )
+            server_name = response["server_name"]
 
-            for server_name, response_keys in processed_response.items():
-                keys.setdefault(server_name, {}).update(response_keys)
+            keys.setdefault(server_name, {}).update(processed_response)
 
         yield logcontext.make_deferred_yieldable(defer.gatherResults(
             [
@@ -517,7 +518,7 @@ class Keyring(object):
 
     @defer.inlineCallbacks
     def get_server_verify_key_v2_direct(self, server_name, key_ids):
-        keys = {}
+        keys = {}  # type: dict[str, nacl.signing.VerifyKey]
 
         for requested_key_id in key_ids:
             if requested_key_id in keys:
@@ -542,6 +543,11 @@ class Keyring(object):
                     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],
@@ -550,24 +556,45 @@ class Keyring(object):
 
             keys.update(response_keys)
 
-        yield logcontext.make_deferred_yieldable(defer.gatherResults(
-            [
-                run_in_background(
-                    self.store_keys,
-                    server_name=key_server_name,
-                    from_server=server_name,
-                    verify_keys=verify_keys,
-                )
-                for key_server_name, verify_keys in keys.items()
-            ],
-            consumeErrors=True
-        ).addErrback(unwrapFirstError))
-
-        defer.returnValue(keys)
+        yield self.store_keys(
+            server_name=server_name,
+            from_server=server_name,
+            verify_keys=keys,
+        )
+        defer.returnValue({server_name: keys})
 
     @defer.inlineCallbacks
-    def process_v2_response(self, from_server, response_json,
-                            requested_ids=[], only_from_server=True):
+    def process_v2_response(
+        self, from_server, response_json, requested_ids=[],
+    ):
+        """Parse a 'Server Keys' structure from the result of a /key request
+
+        This is used to parse either the entirety of the response from
+        GET /_matrix/key/v2/server, or a single entry from the list returned by
+        POST /_matrix/key/v2/query.
+
+        Checks that each signature in the response that claims to come from the origin
+        server is valid. (Does not check that there actually is such a signature, for
+        some reason.)
+
+        Stores the json in server_keys_json so that it can be used for future responses
+        to /_matrix/key/v2/query.
+
+        Args:
+            from_server (str): the name of the server producing this result: either
+                the origin server for a /_matrix/key/v2/server request, or the notary
+                for a /_matrix/key/v2/query.
+
+            response_json (dict): the json-decoded Server Keys response object
+
+            requested_ids (iterable[str]): a list of the key IDs that were requested.
+                We will store the json for these key ids as well as any that are
+                actually in the response
+
+        Returns:
+            Deferred[dict[str, nacl.signing.VerifyKey]]:
+                map from key_id to key object
+        """
         time_now_ms = self.clock.time_msec()
         response_keys = {}
         verify_keys = {}
@@ -589,15 +616,7 @@ class Keyring(object):
                 verify_key.time_added = time_now_ms
                 old_verify_keys[key_id] = verify_key
 
-        results = {}
         server_name = response_json["server_name"]
-        if only_from_server:
-            if server_name != from_server:
-                raise KeyLookupError(
-                    "Expected a response for server %r not %r" % (
-                        from_server, server_name
-                    )
-                )
         for key_id in response_json["signatures"].get(server_name, {}):
             if key_id not in response_json["verify_keys"]:
                 raise KeyLookupError(
@@ -643,9 +662,7 @@ class Keyring(object):
             consumeErrors=True,
         ).addErrback(unwrapFirstError))
 
-        results[server_name] = response_keys
-
-        defer.returnValue(results)
+        defer.returnValue(response_keys)
 
     def store_keys(self, server_name, from_server, verify_keys):
         """Store a collection of verify keys for a given server
diff --git a/synapse/storage/keys.py b/synapse/storage/keys.py
index 030cd1e5a3..f24ab3eedd 100644
--- a/synapse/storage/keys.py
+++ b/synapse/storage/keys.py
@@ -188,8 +188,8 @@ class KeyStore(SQLBaseStore):
         Args:
             server_keys (list): List of (server_name, key_id, source) triplets.
         Returns:
-            Dict mapping (server_name, key_id, source) triplets to dicts with
-            "ts_valid_until_ms" and "key_json" keys.
+            Deferred[dict[Tuple[str, str, str|None], list[dict]]]:
+                Dict mapping (server_name, key_id, source) triplets to lists of dicts
         """
 
         def _get_server_keys_json_txn(txn):
diff --git a/tests/crypto/test_keyring.py b/tests/crypto/test_keyring.py
index c30a1a69e7..b224fdb23a 100644
--- a/tests/crypto/test_keyring.py
+++ b/tests/crypto/test_keyring.py
@@ -16,6 +16,7 @@ import time
 
 from mock import Mock
 
+import canonicaljson
 import signedjson.key
 import signedjson.sign
 
@@ -23,6 +24,7 @@ from twisted.internet import defer
 
 from synapse.api.errors import SynapseError
 from synapse.crypto import keyring
+from synapse.crypto.keyring import KeyLookupError
 from synapse.util import logcontext
 from synapse.util.logcontext import LoggingContext
 
@@ -48,6 +50,9 @@ class MockPerspectiveServer(object):
                 key_id: {"key": signedjson.key.encode_verify_key_base64(verify_key)}
             },
         }
+        return self.get_signed_response(res)
+
+    def get_signed_response(self, res):
         signedjson.sign.sign_json(res, self.server_name, self.key)
         return res
 
@@ -202,6 +207,131 @@ class KeyringTestCase(unittest.HomeserverTestCase):
         self.assertFalse(d.called)
         self.get_success(d)
 
+    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)
+        testkey = signedjson.key.generate_signing_key("ver1")
+        testverifykey = signedjson.key.get_verify_key(testkey)
+        testverifykey_id = "ed25519:ver1"
+        VALID_UNTIL_TS = 1000
+
+        # valid response
+        response = {
+            "server_name": SERVER_NAME,
+            "old_verify_keys": {},
+            "valid_until_ts": VALID_UNTIL_TS,
+            "verify_keys": {
+                testverifykey_id: {
+                    "key": signedjson.key.encode_verify_key_base64(testverifykey)
+                }
+            },
+        }
+        signedjson.sign.sign_json(response, SERVER_NAME, testkey)
+
+        def get_json(destination, path, **kwargs):
+            self.assertEqual(destination, SERVER_NAME)
+            self.assertEqual(path, "/_matrix/key/v2/server/key1")
+            return response
+
+        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))
+        k = keys[SERVER_NAME][testverifykey_id]
+        self.assertEqual(k, testverifykey)
+        self.assertEqual(k.alg, "ed25519")
+        self.assertEqual(k.version, "ver1")
+
+        # check that the perspectives store is correctly updated
+        lookup_triplet = (SERVER_NAME, testverifykey_id, None)
+        key_json = self.get_success(
+            self.hs.get_datastore().get_server_keys_json([lookup_triplet])
+        )
+        res = key_json[lookup_triplet]
+        self.assertEqual(len(res), 1)
+        res = res[0]
+        self.assertEqual(res["key_id"], testverifykey_id)
+        self.assertEqual(res["from_server"], SERVER_NAME)
+        self.assertEqual(res["ts_added_ms"], self.reactor.seconds() * 1000)
+        self.assertEqual(res["ts_valid_until_ms"], VALID_UNTIL_TS)
+
+        # we expect it to be encoded as canonical json *before* it hits the db
+        self.assertEqual(
+            bytes(res["key_json"]), canonicaljson.encode_canonical_json(response)
+        )
+
+        # 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
+        )
+
+    def test_get_keys_from_perspectives(self):
+        # arbitrarily advance the clock a bit
+        self.reactor.advance(100)
+
+        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"
+        VALID_UNTIL_TS = 200 * 1000
+
+        # valid response
+        response = {
+            "server_name": SERVER_NAME,
+            "old_verify_keys": {},
+            "valid_until_ts": VALID_UNTIL_TS,
+            "verify_keys": {
+                testverifykey_id: {
+                    "key": signedjson.key.encode_verify_key_base64(testverifykey)
+                }
+            },
+        }
+
+        persp_resp = {
+            "server_keys": [self.mock_perspective_server.get_signed_response(response)]
+        }
+
+        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 key
+            q = data["server_keys"]
+            self.assertEqual(list(q[SERVER_NAME].keys()), ["key1"])
+            return persp_resp
+
+        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))
+        self.assertIn(SERVER_NAME, keys)
+        k = keys[SERVER_NAME][testverifykey_id]
+        self.assertEqual(k, testverifykey)
+        self.assertEqual(k.alg, "ed25519")
+        self.assertEqual(k.version, "ver1")
+
+        # check that the perspectives store is correctly updated
+        lookup_triplet = (SERVER_NAME, testverifykey_id, None)
+        key_json = self.get_success(
+            self.hs.get_datastore().get_server_keys_json([lookup_triplet])
+        )
+        res = key_json[lookup_triplet]
+        self.assertEqual(len(res), 1)
+        res = res[0]
+        self.assertEqual(res["key_id"], testverifykey_id)
+        self.assertEqual(res["ts_added_ms"], self.reactor.seconds() * 1000)
+        self.assertEqual(res["ts_valid_until_ms"], VALID_UNTIL_TS)
+
+        self.assertEqual(
+            bytes(res["key_json"]),
+            canonicaljson.encode_canonical_json(persp_resp["server_keys"][0]),
+        )
+
 
 @defer.inlineCallbacks
 def run_in_context(f, *args, **kwargs):