Modify StoreKeyFetcher to read from server_keys_json. (#15417)

Before this change:

* `PerspectivesKeyFetcher` and `ServerKeyFetcher` write to `server_keys_json`.
* `PerspectivesKeyFetcher` also writes to `server_signature_keys`.
* `StoreKeyFetcher` reads from `server_signature_keys`.

After this change:

* `PerspectivesKeyFetcher` and `ServerKeyFetcher` write to `server_keys_json`.
* `PerspectivesKeyFetcher` also writes to `server_signature_keys`.
* `StoreKeyFetcher` reads from `server_keys_json`.

This results in `StoreKeyFetcher` now using the results from `ServerKeyFetcher`
in addition to those from `PerspectivesKeyFetcher`, i.e. keys which are directly
fetched from a server will now be pulled from the database instead of refetched.

An additional minor change is included to avoid creating a `PerspectivesKeyFetcher`
(and checking it) if no `trusted_key_servers` are configured.

The overall impact of this should be better usage of cached results:

* If a server has no trusted key servers configured then it should reduce how often keys
  are fetched.
* if a server's trusted key server does not have a requested server's keys cached then it
  should reduce how often keys are directly fetched.

4 files changed, 58 insertions, 48 deletions

diff --git a/tests/crypto/test_keyring.py b/tests/crypto/test_keyring.py
index 66102ab934..7c63b2ea4c 100644
--- a/tests/crypto/test_keyring.py
+++ b/tests/crypto/test_keyring.py
@@ -190,10 +190,23 @@ class KeyringTestCase(unittest.HomeserverTestCase):
         kr = keyring.Keyring(self.hs)
 
         key1 = signedjson.key.generate_signing_key("1")
-        r = self.hs.get_datastores().main.store_server_verify_keys(
+        r = self.hs.get_datastores().main.store_server_keys_json(
             "server9",
-            int(time.time() * 1000),
-            {("server9", get_key_id(key1)): FetchKeyResult(get_verify_key(key1), 1000)},
+            get_key_id(key1),
+            from_server="test",
+            ts_now_ms=int(time.time() * 1000),
+            ts_expires_ms=1000,
+            # The entire response gets signed & stored, just include the bits we
+            # care about.
+            key_json_bytes=canonicaljson.encode_canonical_json(
+                {
+                    "verify_keys": {
+                        get_key_id(key1): {
+                            "key": encode_verify_key_base64(get_verify_key(key1))
+                        }
+                    }
+                }
+            ),
         )
         self.get_success(r)
 
@@ -280,17 +293,13 @@ class KeyringTestCase(unittest.HomeserverTestCase):
         mock_fetcher = Mock()
         mock_fetcher.get_keys = Mock(return_value=make_awaitable({}))
 
-        kr = keyring.Keyring(
-            self.hs, key_fetchers=(StoreKeyFetcher(self.hs), mock_fetcher)
-        )
-
         key1 = signedjson.key.generate_signing_key("1")
-        r = self.hs.get_datastores().main.store_server_verify_keys(
+        r = self.hs.get_datastores().main.store_server_signature_keys(
             "server9",
             int(time.time() * 1000),
             # None is not a valid value in FetchKeyResult, but we're abusing this
             # API to insert null values into the database. The nulls get converted
-            # to 0 when fetched in KeyStore.get_server_verify_keys.
+            # to 0 when fetched in KeyStore.get_server_signature_keys.
             {("server9", get_key_id(key1)): FetchKeyResult(get_verify_key(key1), None)},  # type: ignore[arg-type]
         )
         self.get_success(r)
@@ -298,27 +307,12 @@ class KeyringTestCase(unittest.HomeserverTestCase):
         json1: JsonDict = {}
         signedjson.sign.sign_json(json1, "server9", key1)
 
-        # should fail immediately on an unsigned object
-        d = kr.verify_json_for_server("server9", {}, 0)
-        self.get_failure(d, SynapseError)
-
-        # should fail on a signed object with a non-zero minimum_valid_until_ms,
-        # as it tries to refetch the keys and fails.
-        d = kr.verify_json_for_server("server9", json1, 500)
-        self.get_failure(d, SynapseError)
-
-        # We expect the keyring tried to refetch the key once.
-        mock_fetcher.get_keys.assert_called_once_with(
-            "server9", [get_key_id(key1)], 500
-        )
-
         # should succeed on a signed object with a 0 minimum_valid_until_ms
-        d = kr.verify_json_for_server(
-            "server9",
-            json1,
-            0,
+        d = self.hs.get_datastores().main.get_server_signature_keys(
+            [("server9", get_key_id(key1))]
         )
-        self.get_success(d)
+        result = self.get_success(d)
+        self.assertEquals(result[("server9", get_key_id(key1))].valid_until_ts, 0)
 
     def test_verify_json_dedupes_key_requests(self) -> None:
         """Two requests for the same key should be deduped."""
@@ -464,7 +458,9 @@ class ServerKeyFetcherTestCase(unittest.HomeserverTestCase):
         # check that the perspectives store is correctly updated
         lookup_triplet = (SERVER_NAME, testverifykey_id, None)
         key_json = self.get_success(
-            self.hs.get_datastores().main.get_server_keys_json([lookup_triplet])
+            self.hs.get_datastores().main.get_server_keys_json_for_remote(
+                [lookup_triplet]
+            )
         )
         res_keys = key_json[lookup_triplet]
         self.assertEqual(len(res_keys), 1)
@@ -582,7 +578,9 @@ class PerspectivesKeyFetcherTestCase(unittest.HomeserverTestCase):
         # check that the perspectives store is correctly updated
         lookup_triplet = (SERVER_NAME, testverifykey_id, None)
         key_json = self.get_success(
-            self.hs.get_datastores().main.get_server_keys_json([lookup_triplet])
+            self.hs.get_datastores().main.get_server_keys_json_for_remote(
+                [lookup_triplet]
+            )
         )
         res_keys = key_json[lookup_triplet]
         self.assertEqual(len(res_keys), 1)
@@ -703,7 +701,9 @@ class PerspectivesKeyFetcherTestCase(unittest.HomeserverTestCase):
         # check that the perspectives store is correctly updated
         lookup_triplet = (SERVER_NAME, testverifykey_id, None)
         key_json = self.get_success(
-            self.hs.get_datastores().main.get_server_keys_json([lookup_triplet])
+            self.hs.get_datastores().main.get_server_keys_json_for_remote(
+                [lookup_triplet]
+            )
         )
         res_keys = key_json[lookup_triplet]
         self.assertEqual(len(res_keys), 1)
diff --git a/tests/storage/test_keys.py b/tests/storage/test_keys.py
index 5901d80f26..5d7c13e6d0 100644
--- a/tests/storage/test_keys.py
+++ b/tests/storage/test_keys.py
@@ -37,13 +37,13 @@ KEY_2 = decode_verify_key_base64(
 
 
 class KeyStoreTestCase(tests.unittest.HomeserverTestCase):
-    def test_get_server_verify_keys(self) -> None:
+    def test_get_server_signature_keys(self) -> None:
         store = self.hs.get_datastores().main
 
         key_id_1 = "ed25519:key1"
         key_id_2 = "ed25519:KEY_ID_2"
         self.get_success(
-            store.store_server_verify_keys(
+            store.store_server_signature_keys(
                 "from_server",
                 10,
                 {
@@ -54,7 +54,7 @@ class KeyStoreTestCase(tests.unittest.HomeserverTestCase):
         )
 
         res = self.get_success(
-            store.get_server_verify_keys(
+            store.get_server_signature_keys(
                 [
                     ("server1", key_id_1),
                     ("server1", key_id_2),
@@ -87,7 +87,7 @@ class KeyStoreTestCase(tests.unittest.HomeserverTestCase):
         key_id_2 = "ed25519:key2"
 
         self.get_success(
-            store.store_server_verify_keys(
+            store.store_server_signature_keys(
                 "from_server",
                 0,
                 {
@@ -98,7 +98,7 @@ class KeyStoreTestCase(tests.unittest.HomeserverTestCase):
         )
 
         res = self.get_success(
-            store.get_server_verify_keys([("srv1", key_id_1), ("srv1", key_id_2)])
+            store.get_server_signature_keys([("srv1", key_id_1), ("srv1", key_id_2)])
         )
         self.assertEqual(len(res.keys()), 2)
 
@@ -111,20 +111,20 @@ class KeyStoreTestCase(tests.unittest.HomeserverTestCase):
         self.assertEqual(res2.valid_until_ts, 200)
 
         # we should be able to look up the same thing again without a db hit
-        res = self.get_success(store.get_server_verify_keys([("srv1", key_id_1)]))
+        res = self.get_success(store.get_server_signature_keys([("srv1", key_id_1)]))
         self.assertEqual(len(res.keys()), 1)
         self.assertEqual(res[("srv1", key_id_1)].verify_key, KEY_1)
 
         new_key_2 = signedjson.key.get_verify_key(
             signedjson.key.generate_signing_key("key2")
         )
-        d = store.store_server_verify_keys(
+        d = store.store_server_signature_keys(
             "from_server", 10, {("srv1", key_id_2): FetchKeyResult(new_key_2, 300)}
         )
         self.get_success(d)
 
         res = self.get_success(
-            store.get_server_verify_keys([("srv1", key_id_1), ("srv1", key_id_2)])
+            store.get_server_signature_keys([("srv1", key_id_1), ("srv1", key_id_2)])
         )
         self.assertEqual(len(res.keys()), 2)
 
diff --git a/tests/unittest.py b/tests/unittest.py
index 96ae8fca67..ee2f78ab01 100644
--- a/tests/unittest.py
+++ b/tests/unittest.py
@@ -69,7 +69,6 @@ from synapse.logging.context import (
 )
 from synapse.rest import RegisterServletsFunc
 from synapse.server import HomeServer
-from synapse.storage.keys import FetchKeyResult
 from synapse.types import JsonDict, Requester, UserID, create_requester
 from synapse.util import Clock
 from synapse.util.httpresourcetree import create_resource_tree
@@ -848,15 +847,23 @@ class FederatingHomeserverTestCase(HomeserverTestCase):
         verify_key_id = "%s:%s" % (verify_key.alg, verify_key.version)
 
         self.get_success(
-            hs.get_datastores().main.store_server_verify_keys(
+            hs.get_datastores().main.store_server_keys_json(
+                self.OTHER_SERVER_NAME,
+                verify_key_id,
                 from_server=self.OTHER_SERVER_NAME,
-                ts_added_ms=clock.time_msec(),
-                verify_keys={
-                    (self.OTHER_SERVER_NAME, verify_key_id): FetchKeyResult(
-                        verify_key=verify_key,
-                        valid_until_ts=clock.time_msec() + 10000,
-                    ),
-                },
+                ts_now_ms=clock.time_msec(),
+                ts_expires_ms=clock.time_msec() + 10000,
+                key_json_bytes=canonicaljson.encode_canonical_json(
+                    {
+                        "verify_keys": {
+                            verify_key_id: {
+                                "key": signedjson.key.encode_verify_key_base64(
+                                    verify_key
+                                )
+                            }
+                        }
+                    }
+                ),
             )
         )
 
diff --git a/tests/utils.py b/tests/utils.py
index a0ac11bc5c..e73b46944b 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -131,6 +131,9 @@ def default_config(
         # the test signing key is just an arbitrary ed25519 key to keep the config
         # parser happy
         "signing_key": "ed25519 a_lPym qvioDNmfExFBRPgdTU+wtFYKq4JfwFRv7sYVgWvmgJg",
+        # Disable trusted key servers, otherwise unit tests might try to actually
+        # reach out to matrix.org.
+        "trusted_key_servers": [],
         "event_cache_size": 1,
         "enable_registration": True,
         "enable_registration_captcha": False,