Merge pull request #2459 from matrix-org/rav/keyring_cleanups

Clean up Keyring code

synapse/crypto/keyring.py

@@ -18,7 +18,7 @@ from synapse.crypto.keyclient import fetch_server_key
 from synapse.api.errors import SynapseError, Codes
 from synapse.util import unwrapFirstError, logcontext
 from synapse.util.logcontext import (
-    preserve_context_over_fn, PreserveLoggingContext,
+    PreserveLoggingContext,
     preserve_fn
 )
 from synapse.util.metrics import Measure
@@ -57,7 +57,8 @@ Attributes:
     json_object(dict): The JSON object to verify.
     deferred(twisted.internet.defer.Deferred):
         A deferred (server_name, key_id, verify_key) tuple that resolves when
-        a verify key has been fetched
+        a verify key has been fetched. The deferreds' callbacks are run with no
+        logcontext.
 """
 
 
@@ -82,9 +83,11 @@ class Keyring(object):
         self.key_downloads = {}
 
     def verify_json_for_server(self, server_name, json_object):
-        return self.verify_json_objects_for_server(
+        return logcontext.make_deferred_yieldable(
+            self.verify_json_objects_for_server(
                 [(server_name, json_object)]
             )[0]
+        )
 
     def verify_json_objects_for_server(self, server_and_json):
         """Bulk verifies signatures of json objects, bulk fetching keys as
@@ -94,8 +97,10 @@ class Keyring(object):
             server_and_json (list): List of pairs of (server_name, json_object)
 
         Returns:
-            list of deferreds indicating success or failure to verify each
+            List<Deferred>: for each input pair, a deferred indicating success
-            json object's signature for the given server_name.
+                or failure to verify each json object's signature for the given
+                server_name. The deferreds run their callbacks in the sentinel
+                logcontext.
         """
         verify_requests = []
 
@@ -122,73 +127,59 @@ class Keyring(object):
 
             verify_requests.append(verify_request)
 
+        preserve_fn(self._start_key_lookups)(verify_requests)
+
+        # Pass those keys to handle_key_deferred so that the json object
+        # signatures can be verified
+        handle = preserve_fn(_handle_key_deferred)
+        return [
+            handle(rq) for rq in verify_requests
+        ]
+
     @defer.inlineCallbacks
-        def handle_key_deferred(verify_request):
+    def _start_key_lookups(self, verify_requests):
-            server_name = verify_request.server_name
+        """Sets off the key fetches for each verify request
-            try:
-                _, key_id, verify_key = yield verify_request.deferred
-            except IOError as e:
-                logger.warn(
-                    "Got IOError when downloading keys for %s: %s %s",
-                    server_name, type(e).__name__, str(e.message),
-                )
-                raise SynapseError(
-                    502,
-                    "Error downloading keys for %s" % (server_name,),
-                    Codes.UNAUTHORIZED,
-                )
-            except Exception as e:
-                logger.exception(
-                    "Got Exception when downloading keys for %s: %s %s",
-                    server_name, type(e).__name__, str(e.message),
-                )
-                raise SynapseError(
-                    401,
-                    "No key for %s with id %s" % (server_name, key_ids),
-                    Codes.UNAUTHORIZED,
-                )
 
-            json_object = verify_request.json_object
+        Once each fetch completes, verify_request.deferred will be resolved.
 
-            logger.debug("Got key %s %s:%s for server %s, verifying" % (
+        Args:
-                key_id, verify_key.alg, verify_key.version, server_name,
+            verify_requests (List[VerifyKeyRequest]):
-            ))
+        """
-            try:
-                verify_signed_json(json_object, server_name, verify_key)
-            except:
-                raise SynapseError(
-                    401,
-                    "Invalid signature for server %s with key %s:%s" % (
-                        server_name, verify_key.alg, verify_key.version
-                    ),
-                    Codes.UNAUTHORIZED,
-                )
 
+        # create a deferred for each server we're going to look up the keys
+        # for; we'll resolve them once we have completed our lookups.
+        # These will be passed into wait_for_previous_lookups to block
+        # any other lookups until we have finished.
+        # The deferreds are called with no logcontext.
         server_to_deferred = {
-            server_name: defer.Deferred()
+            rq.server_name: defer.Deferred()
-            for server_name, _ in server_and_json
+            for rq in verify_requests
         }
 
-        with PreserveLoggingContext():
-
         # We want to wait for any previous lookups to complete before
         # proceeding.
-            wait_on_deferred = self.wait_for_previous_lookups(
+        yield self.wait_for_previous_lookups(
-                [server_name for server_name, _ in server_and_json],
+            [rq.server_name for rq in verify_requests],
             server_to_deferred,
         )
 
         # Actually start fetching keys.
-            wait_on_deferred.addBoth(
+        self._get_server_verify_keys(verify_requests)
-                lambda _: self.get_server_verify_keys(verify_requests)
-            )
 
         # When we've finished fetching all the keys for a given server_name,
         # resolve the deferred passed to `wait_for_previous_lookups` so that
         # any lookups waiting will proceed.
+        #
+        # map from server name to a set of request ids
         server_to_request_ids = {}
 
-            def remove_deferreds(res, server_name, verify_request):
+        for verify_request in verify_requests:
+            server_name = verify_request.server_name
+            request_id = id(verify_request)
+            server_to_request_ids.setdefault(server_name, set()).add(request_id)
+
+        def remove_deferreds(res, verify_request):
+            server_name = verify_request.server_name
             request_id = id(verify_request)
             server_to_request_ids[server_name].discard(request_id)
             if not server_to_request_ids[server_name]:
@@ -198,20 +189,10 @@ class Keyring(object):
             return res
 
         for verify_request in verify_requests:
-                server_name = verify_request.server_name
-                request_id = id(verify_request)
-                server_to_request_ids.setdefault(server_name, set()).add(request_id)
             verify_request.deferred.addBoth(
-                    remove_deferreds, server_name, verify_request,
+                remove_deferreds, verify_request,
             )
 
-        # Pass those keys to handle_key_deferred so that the json object
-        # signatures can be verified
-        return [
-            preserve_context_over_fn(handle_key_deferred, verify_request)
-            for verify_request in verify_requests
-        ]
-
     @defer.inlineCallbacks
     def wait_for_previous_lookups(self, server_names, server_to_deferred):
         """Waits for any previous key lookups for the given servers to finish.
@@ -247,7 +228,7 @@ class Keyring(object):
             self.key_downloads[server_name] = deferred
             deferred.addBoth(rm, server_name)
 
-    def get_server_verify_keys(self, verify_requests):
+    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
@@ -316,6 +297,7 @@ class Keyring(object):
                     if not missing_keys:
                         break
 
+                with PreserveLoggingContext():
                     for verify_request in requests_missing_keys.values():
                         verify_request.deferred.errback(SynapseError(
                             401,
@@ -326,11 +308,12 @@ class Keyring(object):
                         ))
 
         def on_err(err):
+            with PreserveLoggingContext():
                 for verify_request in verify_requests:
                     if not verify_request.deferred.called:
                         verify_request.deferred.errback(err)
 
-        do_iterations().addErrback(on_err)
+        preserve_fn(do_iterations)().addErrback(on_err)
 
     @defer.inlineCallbacks
     def get_keys_from_store(self, server_name_and_key_ids):
@@ -740,3 +723,47 @@ class Keyring(object):
             ],
             consumeErrors=True,
         ).addErrback(unwrapFirstError))
+
+
+@defer.inlineCallbacks
+def _handle_key_deferred(verify_request):
+    server_name = verify_request.server_name
+    try:
+        with PreserveLoggingContext():
+            _, key_id, verify_key = yield verify_request.deferred
+    except IOError as e:
+        logger.warn(
+            "Got IOError when downloading keys for %s: %s %s",
+            server_name, type(e).__name__, str(e.message),
+        )
+        raise SynapseError(
+            502,
+            "Error downloading keys for %s" % (server_name,),
+            Codes.UNAUTHORIZED,
+        )
+    except Exception as e:
+        logger.exception(
+            "Got Exception when downloading keys for %s: %s %s",
+            server_name, type(e).__name__, str(e.message),
+        )
+        raise SynapseError(
+            401,
+            "No key for %s with id %s" % (server_name, verify_request.key_ids),
+            Codes.UNAUTHORIZED,
+        )
+
+    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:
+        raise SynapseError(
+            401,
+            "Invalid signature for server %s with key %s:%s" % (
+                server_name, verify_key.alg, verify_key.version
+            ),
+            Codes.UNAUTHORIZED,
+        )

synapse/federation/federation_base.py

@@ -18,8 +18,7 @@ from synapse.api.errors import SynapseError
 from synapse.crypto.event_signing import check_event_content_hash
 from synapse.events import spamcheck
 from synapse.events.utils import prune_event
-from synapse.util import unwrapFirstError
+from synapse.util import unwrapFirstError, logcontext
-from synapse.util.logcontext import preserve_context_over_deferred, preserve_fn
 from twisted.internet import defer
 
 logger = logging.getLogger(__name__)
@@ -51,56 +50,52 @@ class FederationBase(object):
         """
         deferreds = self._check_sigs_and_hashes(pdus)
 
-        def callback(pdu):
+        @defer.inlineCallbacks
-            return pdu
+        def handle_check_result(pdu, deferred):
+            try:
+                res = yield logcontext.make_deferred_yieldable(deferred)
+            except SynapseError:
+                res = None
 
-        def errback(failure, pdu):
-            failure.trap(SynapseError)
-            return None
-
-        def try_local_db(res, pdu):
             if not res:
                 # Check local db.
-                return self.store.get_event(
+                res = yield self.store.get_event(
                     pdu.event_id,
                     allow_rejected=True,
                     allow_none=True,
                 )
-            return res
 
-        def try_remote(res, pdu):
             if not res and pdu.origin != origin:
-                return self.get_pdu(
+                try:
+                    res = yield self.get_pdu(
                         destinations=[pdu.origin],
                         event_id=pdu.event_id,
                         outlier=outlier,
                         timeout=10000,
-                ).addErrback(lambda e: None)
+                    )
-            return res
+                except SynapseError:
+                    pass
 
-        def warn(res, pdu):
             if not res:
                 logger.warn(
                     "Failed to find copy of %s with valid signature",
                     pdu.event_id,
                 )
-            return res
 
-        for pdu, deferred in zip(pdus, deferreds):
+            defer.returnValue(res)
-            deferred.addCallbacks(
+
-                callback, errback, errbackArgs=[pdu]
+        handle = logcontext.preserve_fn(handle_check_result)
-            ).addCallback(
+        deferreds2 = [
-                try_local_db, pdu
+            handle(pdu, deferred)
-            ).addCallback(
+            for pdu, deferred in zip(pdus, deferreds)
-                try_remote, pdu
+        ]
-            ).addCallback(
+
-                warn, pdu
+        valid_pdus = yield logcontext.make_deferred_yieldable(
+            defer.gatherResults(
+                deferreds2,
+                consumeErrors=True,
             )
-
+        ).addErrback(unwrapFirstError)
-        valid_pdus = yield preserve_context_over_deferred(defer.gatherResults(
-            deferreds,
-            consumeErrors=True
-        )).addErrback(unwrapFirstError)
 
         if include_none:
             defer.returnValue(valid_pdus)
@@ -108,7 +103,9 @@ class FederationBase(object):
             defer.returnValue([p for p in valid_pdus if p])
 
     def _check_sigs_and_hash(self, pdu):
-        return self._check_sigs_and_hashes([pdu])[0]
+        return logcontext.make_deferred_yieldable(
+            self._check_sigs_and_hashes([pdu])[0],
+        )
 
     def _check_sigs_and_hashes(self, pdus):
         """Checks that each of the received events is correctly signed by the
@@ -123,6 +120,7 @@ class FederationBase(object):
               * returns a redacted version of the event (if the signature
                 matched but the hash did not)
               * throws a SynapseError if the signature check failed.
+            The deferreds run their callbacks in the sentinel logcontext.
         """
 
         redacted_pdus = [
@@ -130,12 +128,15 @@ class FederationBase(object):
             for pdu in pdus
         ]
 
-        deferreds = preserve_fn(self.keyring.verify_json_objects_for_server)([
+        deferreds = self.keyring.verify_json_objects_for_server([
             (p.origin, p.get_pdu_json())
             for p in redacted_pdus
         ])
 
+        ctx = logcontext.LoggingContext.current_context()
+
         def callback(_, pdu, redacted):
+            with logcontext.PreserveLoggingContext(ctx):
                 if not check_event_content_hash(pdu):
                     logger.warn(
                         "Event content has been tampered, redacting %s: %s",
@@ -154,6 +155,7 @@ class FederationBase(object):
 
         def errback(failure, pdu):
             failure.trap(SynapseError)
+            with logcontext.PreserveLoggingContext(ctx):
                 logger.warn(
                     "Signature check failed for %s",
                     pdu.event_id,

synapse/federation/federation_client.py

@@ -22,7 +22,7 @@ from synapse.api.constants import Membership
 from synapse.api.errors import (
     CodeMessageException, HttpResponseException, SynapseError,
 )
-from synapse.util import unwrapFirstError
+from synapse.util import unwrapFirstError, logcontext
 from synapse.util.caches.expiringcache import ExpiringCache
 from synapse.util.logutils import log_function
 from synapse.util.logcontext import preserve_fn, preserve_context_over_deferred
@@ -189,10 +189,10 @@ class FederationClient(FederationBase):
         ]
 
         # FIXME: We should handle signature failures more gracefully.
-        pdus[:] = yield preserve_context_over_deferred(defer.gatherResults(
+        pdus[:] = yield logcontext.make_deferred_yieldable(defer.gatherResults(
             self._check_sigs_and_hashes(pdus),
             consumeErrors=True,
-        )).addErrback(unwrapFirstError)
+        ).addErrback(unwrapFirstError))
 
         defer.returnValue(pdus)
 
@@ -252,7 +252,7 @@ class FederationClient(FederationBase):
                     pdu = pdu_list[0]
 
                     # Check signatures are correct.
-                    signed_pdu = yield self._check_sigs_and_hashes([pdu])[0]
+                    signed_pdu = yield self._check_sigs_and_hash(pdu)
 
                     break
 

synapse/storage/keys.py

@@ -113,30 +113,37 @@ class KeyStore(SQLBaseStore):
                 keys[key_id] = key
         defer.returnValue(keys)
 
-    @defer.inlineCallbacks
     def store_server_verify_key(self, server_name, from_server, time_now_ms,
                                 verify_key):
         """Stores a NACL verification key for the given server.
         Args:
             server_name (str): The name of the server.
-            key_id (str): The version of the key for the server.
             from_server (str): Where the verification key was looked up
-            ts_now_ms (int): The time now in milliseconds
+            time_now_ms (int): The time now in milliseconds
-            verification_key (VerifyKey): The NACL verify key.
+            verify_key (nacl.signing.VerifyKey): The NACL verify key.
         """
-        yield self._simple_upsert(
+        key_id = "%s:%s" % (verify_key.alg, verify_key.version)
+
+        def _txn(txn):
+            self._simple_upsert_txn(
+                txn,
                 table="server_signature_keys",
                 keyvalues={
                     "server_name": server_name,
-                "key_id": "%s:%s" % (verify_key.alg, verify_key.version),
+                    "key_id": key_id,
                 },
                 values={
                     "from_server": from_server,
                     "ts_added_ms": time_now_ms,
                     "verify_key": buffer(verify_key.encode()),
                 },
-            desc="store_server_verify_key",
             )
+            txn.call_after(
+                self._get_server_verify_key.invalidate,
+                (server_name, key_id)
+            )
+
+        return self.runInteraction("store_server_verify_key", _txn)
 
     def store_server_keys_json(self, server_name, key_id, from_server,
                                ts_now_ms, ts_expires_ms, key_json_bytes):

tests/crypto/test_keyring.py

@@ -12,39 +12,72 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import signedjson
+import time
+
+import signedjson.key
+import signedjson.sign
 from mock import Mock
 from synapse.api.errors import SynapseError
 from synapse.crypto import keyring
-from synapse.util import async
+from synapse.util import async, logcontext
 from synapse.util.logcontext import LoggingContext
 from tests import unittest, utils
 from twisted.internet import defer
 
 
+class MockPerspectiveServer(object):
+    def __init__(self):
+        self.server_name = "mock_server"
+        self.key = signedjson.key.generate_signing_key(0)
+
+    def get_verify_keys(self):
+        vk = signedjson.key.get_verify_key(self.key)
+        return {
+            "%s:%s" % (vk.alg, vk.version): vk,
+        }
+
+    def get_signed_key(self, server_name, verify_key):
+        key_id = "%s:%s" % (verify_key.alg, verify_key.version)
+        res = {
+            "server_name": server_name,
+            "old_verify_keys": {},
+            "valid_until_ts": time.time() * 1000 + 3600,
+            "verify_keys": {
+                key_id: {
+                    "key": signedjson.key.encode_verify_key_base64(verify_key)
+                }
+            }
+        }
+        signedjson.sign.sign_json(res, self.server_name, self.key)
+        return res
+
+
 class KeyringTestCase(unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
+        self.mock_perspective_server = MockPerspectiveServer()
         self.http_client = Mock()
         self.hs = yield utils.setup_test_homeserver(
             handlers=None,
             http_client=self.http_client,
         )
         self.hs.config.perspectives = {
-            "persp_server": {"k": "v"}
+            self.mock_perspective_server.server_name:
+                self.mock_perspective_server.get_verify_keys()
         }
 
+    def check_context(self, _, expected):
+        self.assertEquals(
+            getattr(LoggingContext.current_context(), "test_key", None),
+            expected
+        )
+
     @defer.inlineCallbacks
     def test_wait_for_previous_lookups(self):
         sentinel_context = LoggingContext.current_context()
 
         kr = keyring.Keyring(self.hs)
 
-        def check_context(_, expected):
-            self.assertEquals(
-                LoggingContext.current_context().test_key, expected
-            )
-
         lookup_1_deferred = defer.Deferred()
         lookup_2_deferred = defer.Deferred()
 
@@ -60,7 +93,7 @@ class KeyringTestCase(unittest.TestCase):
             self.assertTrue(wait_1_deferred.called)
             # ... so we should have preserved the LoggingContext.
             self.assertIs(LoggingContext.current_context(), context_one)
-            wait_1_deferred.addBoth(check_context, "one")
+            wait_1_deferred.addBoth(self.check_context, "one")
 
         with LoggingContext("two") as context_two:
             context_two.test_key = "two"
@@ -74,7 +107,7 @@ class KeyringTestCase(unittest.TestCase):
             self.assertFalse(wait_2_deferred.called)
             # ... so we should have reset the LoggingContext.
             self.assertIs(LoggingContext.current_context(), sentinel_context)
-            wait_2_deferred.addBoth(check_context, "two")
+            wait_2_deferred.addBoth(self.check_context, "two")
 
             # let the first lookup complete (in the sentinel context)
             lookup_1_deferred.callback(None)
@@ -89,18 +122,40 @@ class KeyringTestCase(unittest.TestCase):
 
         kr = keyring.Keyring(self.hs)
         json1 = {}
-        signedjson.sign.sign_json(json1, "server1", key1)
+        signedjson.sign.sign_json(json1, "server10", key1)
 
-        self.http_client.post_json.return_value = defer.Deferred()
+        persp_resp = {
+            "server_keys": [
+                self.mock_perspective_server.get_signed_key(
+                    "server10",
+                    signedjson.key.get_verify_key(key1)
+                ),
+            ]
+        }
+        persp_deferred = defer.Deferred()
+
+        @defer.inlineCallbacks
+        def get_perspectives(**kwargs):
+            self.assertEquals(
+                LoggingContext.current_context().test_key, "11",
+            )
+            with logcontext.PreserveLoggingContext():
+                yield persp_deferred
+            defer.returnValue(persp_resp)
+        self.http_client.post_json.side_effect = get_perspectives
+
+        with LoggingContext("11") as context_11:
+            context_11.test_key = "11"
 
             # start off a first set of lookups
             res_deferreds = kr.verify_json_objects_for_server(
-            [("server1", json1),
+                [("server10", json1),
-             ("server2", {})
+                 ("server11", {})
                  ]
             )
 
             # the unsigned json should be rejected pretty quickly
+            self.assertTrue(res_deferreds[1].called)
             try:
                 yield res_deferreds[1]
                 self.assertFalse("unsigned json didn't cause a failure")
@@ -108,19 +163,67 @@ class KeyringTestCase(unittest.TestCase):
                 pass
 
             self.assertFalse(res_deferreds[0].called)
+            res_deferreds[0].addBoth(self.check_context, None)
 
             # wait a tick for it to send the request to the perspectives server
             # (it first tries the datastore)
             yield async.sleep(0.005)
             self.http_client.post_json.assert_called_once()
 
-        # a second request for a server with outstanding requests should
+            self.assertIs(LoggingContext.current_context(), context_11)
-        # block rather than start a second call
+
+            context_12 = LoggingContext("12")
+            context_12.test_key = "12"
+            with logcontext.PreserveLoggingContext(context_12):
+                # a second request for a server with outstanding requests
+                # should block rather than start a second call
                 self.http_client.post_json.reset_mock()
                 self.http_client.post_json.return_value = defer.Deferred()
 
-        kr.verify_json_objects_for_server(
+                res_deferreds_2 = kr.verify_json_objects_for_server(
-            [("server1", json1)],
+                    [("server10", json1)],
                 )
                 yield async.sleep(0.005)
                 self.http_client.post_json.assert_not_called()
+                res_deferreds_2[0].addBoth(self.check_context, None)
+
+            # complete the first request
+            with logcontext.PreserveLoggingContext():
+                persp_deferred.callback(persp_resp)
+            self.assertIs(LoggingContext.current_context(), context_11)
+
+            with logcontext.PreserveLoggingContext():
+                yield res_deferreds[0]
+                yield res_deferreds_2[0]
+
+    @defer.inlineCallbacks
+    def test_verify_json_for_server(self):
+        kr = keyring.Keyring(self.hs)
+
+        key1 = signedjson.key.generate_signing_key(1)
+        yield self.hs.datastore.store_server_verify_key(
+            "server9", "", time.time() * 1000,
+            signedjson.key.get_verify_key(key1),
+        )
+        json1 = {}
+        signedjson.sign.sign_json(json1, "server9", key1)
+
+        sentinel_context = LoggingContext.current_context()
+
+        with LoggingContext("one") as context_one:
+            context_one.test_key = "one"
+
+            defer = kr.verify_json_for_server("server9", {})
+            try:
+                yield defer
+                self.fail("should fail on unsigned json")
+            except SynapseError:
+                pass
+            self.assertIs(LoggingContext.current_context(), context_one)
+
+            defer = kr.verify_json_for_server("server9", json1)
+            self.assertFalse(defer.called)
+            self.assertIs(LoggingContext.current_context(), sentinel_context)
+            yield defer
+
+            self.assertIs(LoggingContext.current_context(), context_one)