Merge c01300710e into 3aae60f17b

Per MSC3967, which is now stable, we should not require UIA when
uploading cross-signing keys for the first time.

Fixes: #17227

changelog.d/17154.bugfix

@@ -0,0 +1 @@
+Fixed SQL performance regression introduced in #17044.

changelog.d/17284.feature

@@ -0,0 +1 @@
+Do not require user-interactive authentication for uploading cross-signing keys for the first time, per MSC3967.

synapse/config/experimental.py

@@ -393,9 +393,6 @@ class ExperimentalConfig(Config):
         # MSC3391: Removing account data.
         self.msc3391_enabled = experimental.get("msc3391_enabled", False)
 
-        # MSC3967: Do not require UIA when first uploading cross signing keys
-        self.msc3967_enabled = experimental.get("msc3967_enabled", False)
-
         # MSC3861: Matrix architecture change to delegate authentication via OIDC
         try:
             self.msc3861 = MSC3861(**experimental.get("msc3861", {}))

synapse/rest/admin/experimental_features.py

@@ -41,7 +41,6 @@ class ExperimentalFeature(str, Enum):
 
     MSC3026 = "msc3026"
     MSC3881 = "msc3881"
-    MSC3967 = "msc3967"
 
 
 class ExperimentalFeaturesRestServlet(RestServlet):

synapse/rest/client/keys.py

@@ -382,44 +382,35 @@ class SigningKeyUploadServlet(RestServlet):
             master_key_updatable_without_uia,
         ) = await self.e2e_keys_handler.check_cross_signing_setup(user_id)
 
-        # Before MSC3967 we required UIA both when setting up cross signing for the
-        # first time and when resetting the device signing key. With MSC3967 we only
-        # require UIA when resetting cross-signing, and not when setting up the first
-        # time. Because there is no UIA in MSC3861, for now we throw an error if the
-        # user tries to reset the device signing key when MSC3861 is enabled, but allow
-        # first-time setup.
-        if self.hs.config.experimental.msc3861.enabled:
-            # The auth service has to explicitly mark the master key as replaceable
-            # without UIA to reset the device signing key with MSC3861.
-            if is_cross_signing_setup and not master_key_updatable_without_uia:
-                config = self.hs.config.experimental.msc3861
-                if config.account_management_url is not None:
-                    url = f"{config.account_management_url}?action=org.matrix.cross_signing_reset"
-                else:
-                    url = config.issuer
+        # Resending exactly the same keys should just 200 OK without doing a UIA prompt.
+        keys_are_different = await self.e2e_keys_handler.has_different_keys(
+            user_id, body
+        )
+        if not keys_are_different:
+            return 200, {}
 
-                raise SynapseError(
-                    HTTPStatus.NOT_IMPLEMENTED,
-                    "To reset your end-to-end encryption cross-signing identity, "
-                    f"you first need to approve it at {url} and then try again.",
-                    Codes.UNRECOGNIZED,
-                )
-            # But first-time setup is fine
+        # The keys are different; is x-signing set up? If no, then this is first-time
+        # setup, and that is allowed without UIA, per MSC3967.
+        # If yes, then we need to authenticate the change.
+        if is_cross_signing_setup:
+            # With MSC3861, UIA is not possible. Instead, the auth service has to
+            # explicitly mark the master key as replaceable.
+            if self.hs.config.experimental.msc3861.enabled:
+                if not master_key_updatable_without_uia:
+                    config = self.hs.config.experimental.msc3861
+                    if config.account_management_url is not None:
+                        url = f"{config.account_management_url}?action=org.matrix.cross_signing_reset"
+                    else:
+                        url = config.issuer
 
-        elif self.hs.config.experimental.msc3967_enabled:
-            # MSC3967 allows this endpoint to 200 OK for idempotency. Resending exactly the same
-            # keys should just 200 OK without doing a UIA prompt.
-            keys_are_different = await self.e2e_keys_handler.has_different_keys(
-                user_id, body
-            )
-            if not keys_are_different:
-                # FIXME: we do not fallthrough to upload_signing_keys_for_user because confusingly
-                # if we do, we 500 as it looks like it tries to INSERT the same key twice, causing a
-                # unique key constraint violation. This sounds like a bug?
-                return 200, {}
-            # the keys are different, is x-signing set up? If no, then the keys don't exist which is
-            # why they are different. If yes, then we need to UIA to change them.
-            if is_cross_signing_setup:
+                    raise SynapseError(
+                        HTTPStatus.NOT_IMPLEMENTED,
+                        "To reset your end-to-end encryption cross-signing identity, "
+                        f"you first need to approve it at {url} and then try again.",
+                        Codes.UNRECOGNIZED,
+                    )
+            else:
+                # Without MSC3861, we require UIA.
                 await self.auth_handler.validate_user_via_ui_auth(
                     requester,
                     request,
@@ -428,18 +419,6 @@ class SigningKeyUploadServlet(RestServlet):
                     # Do not allow skipping of UIA auth.
                     can_skip_ui_auth=False,
                 )
-            # Otherwise we don't require UIA since we are setting up cross signing for first time
-        else:
-            # Previous behaviour is to always require UIA but allow it to be skipped
-            await self.auth_handler.validate_user_via_ui_auth(
-                requester,
-                request,
-                body,
-                "add a device signing key to your account",
-                # Allow skipping of UI auth since this is frequently called directly
-                # after login and it is silly to ask users to re-auth immediately.
-                can_skip_ui_auth=True,
-            )
 
         result = await self.e2e_keys_handler.upload_signing_keys_for_user(user_id, body)
         return 200, result

synapse/storage/databases/main/event_federation.py

@@ -280,16 +280,64 @@ class EventFederationWorkerStore(SignatureWorkerStore, EventsWorkerStore, SQLBas
 
         # Now we look up all links for the chains we have, adding chains that
         # are reachable from any event.
+        #
+        # This query is structured to first get all chain IDs reachable, and
+        # then pull out all links from those chains. This does pull out more
+        # rows than is strictly necessary, however there isn't a way of
+        # structuring the recursive part of query to pull out the links without
+        # also returning large quantities of redundant data (which can make it a
+        # lot slower).
+        sql = """
+            WITH RECURSIVE links(chain_id) AS (
+                SELECT
+                    DISTINCT origin_chain_id
+                FROM event_auth_chain_links WHERE %s
+                UNION
+                SELECT
+                    target_chain_id
+                FROM event_auth_chain_links
+                INNER JOIN links ON (chain_id = origin_chain_id)
+            )
+            SELECT
+                origin_chain_id, origin_sequence_number,
+                target_chain_id, target_sequence_number
+            FROM links
+            INNER JOIN event_auth_chain_links ON (chain_id = origin_chain_id)
+        """
 
         # A map from chain ID to max sequence number *reachable* from any event ID.
         chains: Dict[int, int] = {}
-        for links in self._get_chain_links(txn, set(event_chains.keys())):
+
+        # Add all linked chains reachable from initial set of chains.
+        chains_to_fetch = set(event_chains.keys())
+        while chains_to_fetch:
+            batch2 = tuple(itertools.islice(chains_to_fetch, 1000))
+            chains_to_fetch.difference_update(batch2)
+            clause, args = make_in_list_sql_clause(
+                txn.database_engine, "origin_chain_id", batch2
+            )
+            txn.execute(sql % (clause,), args)
+
+            links: Dict[int, List[Tuple[int, int, int]]] = {}
+
+            for (
+                origin_chain_id,
+                origin_sequence_number,
+                target_chain_id,
+                target_sequence_number,
+            ) in txn:
+                links.setdefault(origin_chain_id, []).append(
+                    (origin_sequence_number, target_chain_id, target_sequence_number)
+                )
+
             for chain_id in links:
                 if chain_id not in event_chains:
                     continue
 
                 _materialize(chain_id, event_chains[chain_id], links, chains)
 
+            chains_to_fetch.difference_update(chains)
+
         # Add the initial set of chains, excluding the sequence corresponding to
         # initial event.
         for chain_id, seq_no in event_chains.items():
@@ -579,9 +627,53 @@ class EventFederationWorkerStore(SignatureWorkerStore, EventsWorkerStore, SQLBas
 
         # Now we look up all links for the chains we have, adding chains that
         # are reachable from any event.
+        #
+        # This query is structured to first get all chain IDs reachable, and
+        # then pull out all links from those chains. This does pull out more
+        # rows than is strictly necessary, however there isn't a way of
+        # structuring the recursive part of query to pull out the links without
+        # also returning large quantities of redundant data (which can make it a
+        # lot slower).
+        sql = """
+            WITH RECURSIVE links(chain_id) AS (
+                SELECT
+                    DISTINCT origin_chain_id
+                FROM event_auth_chain_links WHERE %s
+                UNION
+                SELECT
+                    target_chain_id
+                FROM event_auth_chain_links
+                INNER JOIN links ON (chain_id = origin_chain_id)
+            )
+            SELECT
+                origin_chain_id, origin_sequence_number,
+                target_chain_id, target_sequence_number
+            FROM links
+            INNER JOIN event_auth_chain_links ON (chain_id = origin_chain_id)
+        """
+
+        # (We need to take a copy of `seen_chains` as we want to mutate it in
+        # the loop)
+        chains_to_fetch = set(seen_chains)
+        while chains_to_fetch:
+            batch2 = tuple(itertools.islice(chains_to_fetch, 1000))
+            clause, args = make_in_list_sql_clause(
+                txn.database_engine, "origin_chain_id", batch2
+            )
+            txn.execute(sql % (clause,), args)
+
+            links: Dict[int, List[Tuple[int, int, int]]] = {}
+
+            for (
+                origin_chain_id,
+                origin_sequence_number,
+                target_chain_id,
+                target_sequence_number,
+            ) in txn:
+                links.setdefault(origin_chain_id, []).append(
+                    (origin_sequence_number, target_chain_id, target_sequence_number)
+                )
 
-        # (We need to take a copy of `seen_chains` as the function mutates it)
-        for links in self._get_chain_links(txn, set(seen_chains)):
             for chains in set_to_chain:
                 for chain_id in links:
                     if chain_id not in chains:
@@ -589,6 +681,7 @@ class EventFederationWorkerStore(SignatureWorkerStore, EventsWorkerStore, SQLBas
 
                     _materialize(chain_id, chains[chain_id], links, chains)
 
+                chains_to_fetch.difference_update(chains)
                 seen_chains.update(chains)
 
         # Now for each chain we figure out the maximum sequence number reachable

tests/handlers/test_oauth_delegation.py

@@ -541,6 +541,8 @@ class MSC3861OAuthDelegation(HomeserverTestCase):
 
         self.assertEqual(channel.code, 200, channel.json_body)
 
+        # Try uploading *different* keys; it should cause a 501 error.
+        keys_upload_body = self.make_device_keys(USER_ID, DEVICE)
         channel = self.make_request(
             "POST",
             "/_matrix/client/v3/keys/device_signing/upload",

tests/rest/admin/test_admin.py

@@ -435,10 +435,6 @@ class ExperimentalFeaturesTestCase(unittest.HomeserverTestCase):
             True,
             channel.json_body["features"]["msc3881"],
         )
-        self.assertEqual(
-            False,
-            channel.json_body["features"]["msc3967"],
-        )
 
         # test nothing blows up if you try to disable a feature that isn't already enabled
         url = f"{self.url}/{self.other_user}"

tests/rest/client/test_keys.py

@@ -155,71 +155,6 @@ class KeyQueryTestCase(unittest.HomeserverTestCase):
         }
 
     def test_device_signing_with_uia(self) -> None:
-        """Device signing key upload requires UIA."""
-        password = "wonderland"
-        device_id = "ABCDEFGHI"
-        alice_id = self.register_user("alice", password)
-        alice_token = self.login("alice", password, device_id=device_id)
-
-        content = self.make_device_keys(alice_id, device_id)
-
-        channel = self.make_request(
-            "POST",
-            "/_matrix/client/v3/keys/device_signing/upload",
-            content,
-            alice_token,
-        )
-
-        self.assertEqual(channel.code, HTTPStatus.UNAUTHORIZED, channel.result)
-        # Grab the session
-        session = channel.json_body["session"]
-        # Ensure that flows are what is expected.
-        self.assertIn({"stages": ["m.login.password"]}, channel.json_body["flows"])
-
-        # add UI auth
-        content["auth"] = {
-            "type": "m.login.password",
-            "identifier": {"type": "m.id.user", "user": alice_id},
-            "password": password,
-            "session": session,
-        }
-
-        channel = self.make_request(
-            "POST",
-            "/_matrix/client/v3/keys/device_signing/upload",
-            content,
-            alice_token,
-        )
-
-        self.assertEqual(channel.code, HTTPStatus.OK, channel.result)
-
-    @override_config({"ui_auth": {"session_timeout": "15m"}})
-    def test_device_signing_with_uia_session_timeout(self) -> None:
-        """Device signing key upload requires UIA buy passes with grace period."""
-        password = "wonderland"
-        device_id = "ABCDEFGHI"
-        alice_id = self.register_user("alice", password)
-        alice_token = self.login("alice", password, device_id=device_id)
-
-        content = self.make_device_keys(alice_id, device_id)
-
-        channel = self.make_request(
-            "POST",
-            "/_matrix/client/v3/keys/device_signing/upload",
-            content,
-            alice_token,
-        )
-
-        self.assertEqual(channel.code, HTTPStatus.OK, channel.result)
-
-    @override_config(
-        {
-            "experimental_features": {"msc3967_enabled": True},
-            "ui_auth": {"session_timeout": "15s"},
-        }
-    )
-    def test_device_signing_with_msc3967(self) -> None:
-        """Device signing key follows MSC3967 behaviour when enabled."""
         password = "wonderland"
         device_id = "ABCDEFGHI"
         alice_id = self.register_user("alice", password)