Drop support for calling `/_matrix/client/v3/rooms/{roomId}/invite` without an `id_access_token` (#13241)

Fixes #13206

Signed-off-by: Jacek Kusnierz jacek.kusnierz@tum.de

9 files changed, 81 insertions, 137 deletions

diff --git a/changelog.d/13241.removal b/changelog.d/13241.removal
new file mode 100644
index 0000000000..60b0e7969c
--- /dev/null
+++ b/changelog.d/13241.removal
@@ -0,0 +1 @@
+Drop support for calling `/_matrix/client/v3/rooms/{roomId}/invite` without an `id_access_token`, which was not permitted by the spec. Contributed by @Vetchu.
\ No newline at end of file
diff --git a/synapse/handlers/identity.py b/synapse/handlers/identity.py
index 9571d461c8..93d09e9939 100644
--- a/synapse/handlers/identity.py
+++ b/synapse/handlers/identity.py
@@ -538,11 +538,7 @@ class IdentityHandler:
             raise SynapseError(400, "Error contacting the identity server")
 
     async def lookup_3pid(
-        self,
-        id_server: str,
-        medium: str,
-        address: str,
-        id_access_token: Optional[str] = None,
+        self, id_server: str, medium: str, address: str, id_access_token: str
     ) -> Optional[str]:
         """Looks up a 3pid in the passed identity server.
 
@@ -557,60 +553,15 @@ class IdentityHandler:
         Returns:
             the matrix ID of the 3pid, or None if it is not recognized.
         """
-        if id_access_token is not None:
-            try:
-                results = await self._lookup_3pid_v2(
-                    id_server, id_access_token, medium, address
-                )
-                return results
-
-            except Exception as e:
-                # Catch HttpResponseExcept for a non-200 response code
-                # Check if this identity server does not know about v2 lookups
-                if isinstance(e, HttpResponseException) and e.code == 404:
-                    # This is an old identity server that does not yet support v2 lookups
-                    logger.warning(
-                        "Attempted v2 lookup on v1 identity server %s. Falling "
-                        "back to v1",
-                        id_server,
-                    )
-                else:
-                    logger.warning("Error when looking up hashing details: %s", e)
-                    return None
-
-        return await self._lookup_3pid_v1(id_server, medium, address)
-
-    async def _lookup_3pid_v1(
-        self, id_server: str, medium: str, address: str
-    ) -> Optional[str]:
-        """Looks up a 3pid in the passed identity server using v1 lookup.
 
-        Args:
-            id_server: The server name (including port, if required)
-                of the identity server to use.
-            medium: The type of the third party identifier (e.g. "email").
-            address: The third party identifier (e.g. "foo@example.com").
-
-        Returns:
-            the matrix ID of the 3pid, or None if it is not recognized.
-        """
         try:
-            data = await self.blacklisting_http_client.get_json(
-                "%s%s/_matrix/identity/api/v1/lookup" % (id_server_scheme, id_server),
-                {"medium": medium, "address": address},
+            results = await self._lookup_3pid_v2(
+                id_server, id_access_token, medium, address
             )
-
-            if "mxid" in data:
-                # note: we used to verify the identity server's signature here, but no longer
-                # require or validate it. See the following for context:
-                # https://github.com/matrix-org/synapse/issues/5253#issuecomment-666246950
-                return data["mxid"]
-        except RequestTimedOutError:
-            raise SynapseError(500, "Timed out contacting identity server")
-        except OSError as e:
-            logger.warning("Error from v1 identity server lookup: %s" % (e,))
-
-        return None
+            return results
+        except Exception as e:
+            logger.warning("Error when looking up hashing details: %s", e)
+            return None
 
     async def _lookup_3pid_v2(
         self, id_server: str, id_access_token: str, medium: str, address: str
@@ -739,7 +690,7 @@ class IdentityHandler:
         room_type: Optional[str],
         inviter_display_name: str,
         inviter_avatar_url: str,
-        id_access_token: Optional[str] = None,
+        id_access_token: str,
     ) -> Tuple[str, List[Dict[str, str]], Dict[str, str], str]:
         """
         Asks an identity server for a third party invite.
@@ -760,7 +711,7 @@ class IdentityHandler:
             inviter_display_name: The current display name of the
                 inviter.
             inviter_avatar_url: The URL of the inviter's avatar.
-            id_access_token (str|None): The access token to authenticate to the identity
+            id_access_token (str): The access token to authenticate to the identity
                 server with
 
         Returns:
@@ -792,71 +743,24 @@ class IdentityHandler:
             invite_config["org.matrix.web_client_location"] = self._web_client_location
 
         # Add the identity service access token to the JSON body and use the v2
-        # Identity Service endpoints if id_access_token is present
+        # Identity Service endpoints
         data = None
-        base_url = "%s%s/_matrix/identity" % (id_server_scheme, id_server)
 
-        if id_access_token:
-            key_validity_url = "%s%s/_matrix/identity/v2/pubkey/isvalid" % (
-                id_server_scheme,
-                id_server,
-            )
+        key_validity_url = "%s%s/_matrix/identity/v2/pubkey/isvalid" % (
+            id_server_scheme,
+            id_server,
+        )
 
-            # Attempt a v2 lookup
-            url = base_url + "/v2/store-invite"
-            try:
-                data = await self.blacklisting_http_client.post_json_get_json(
-                    url,
-                    invite_config,
-                    {"Authorization": create_id_access_token_header(id_access_token)},
-                )
-            except RequestTimedOutError:
-                raise SynapseError(500, "Timed out contacting identity server")
-            except HttpResponseException as e:
-                if e.code != 404:
-                    logger.info("Failed to POST %s with JSON: %s", url, e)
-                    raise e
-
-        if data is None:
-            key_validity_url = "%s%s/_matrix/identity/api/v1/pubkey/isvalid" % (
-                id_server_scheme,
-                id_server,
+        url = "%s%s/_matrix/identity/v2/store-invite" % (id_server_scheme, id_server)
+        try:
+            data = await self.blacklisting_http_client.post_json_get_json(
+                url,
+                invite_config,
+                {"Authorization": create_id_access_token_header(id_access_token)},
             )
-            url = base_url + "/api/v1/store-invite"
-
-            try:
-                data = await self.blacklisting_http_client.post_json_get_json(
-                    url, invite_config
-                )
-            except RequestTimedOutError:
-                raise SynapseError(500, "Timed out contacting identity server")
-            except HttpResponseException as e:
-                logger.warning(
-                    "Error trying to call /store-invite on %s%s: %s",
-                    id_server_scheme,
-                    id_server,
-                    e,
-                )
-
-            if data is None:
-                # Some identity servers may only support application/x-www-form-urlencoded
-                # types. This is especially true with old instances of Sydent, see
-                # https://github.com/matrix-org/sydent/pull/170
-                try:
-                    data = await self.blacklisting_http_client.post_urlencoded_get_json(
-                        url, invite_config
-                    )
-                except HttpResponseException as e:
-                    logger.warning(
-                        "Error calling /store-invite on %s%s with fallback "
-                        "encoding: %s",
-                        id_server_scheme,
-                        id_server,
-                        e,
-                    )
-                    raise e
-
-        # TODO: Check for success
+        except RequestTimedOutError:
+            raise SynapseError(500, "Timed out contacting identity server")
+
         token = data["token"]
         public_keys = data.get("public_keys", [])
         if "public_key" in data:
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index f64a8690a5..33e9a87002 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -19,6 +19,7 @@ import math
 import random
 import string
 from collections import OrderedDict
+from http import HTTPStatus
 from typing import (
     TYPE_CHECKING,
     Any,
@@ -704,8 +705,8 @@ class RoomCreationHandler:
                 was, requested, `room_alias`. Secondly, the stream_id of the
                 last persisted event.
         Raises:
-            SynapseError if the room ID couldn't be stored, or something went
-            horribly wrong.
+            SynapseError if the room ID couldn't be stored, 3pid invitation config
+            validation failed, or something went horribly wrong.
             ResourceLimitError if server is blocked to some resource being
             exceeded
         """
@@ -731,6 +732,19 @@ class RoomCreationHandler:
         invite_3pid_list = config.get("invite_3pid", [])
         invite_list = config.get("invite", [])
 
+        # validate each entry for correctness
+        for invite_3pid in invite_3pid_list:
+            if not all(
+                key in invite_3pid
+                for key in ("medium", "address", "id_server", "id_access_token")
+            ):
+                raise SynapseError(
+                    HTTPStatus.BAD_REQUEST,
+                    "all of `medium`, `address`, `id_server` and `id_access_token` "
+                    "are required when making a 3pid invite",
+                    Codes.MISSING_PARAM,
+                )
+
         if not is_requester_admin:
             spam_check = await self.spam_checker.user_may_create_room(user_id)
             if spam_check != NOT_SPAM:
@@ -978,7 +992,7 @@ class RoomCreationHandler:
 
         for invite_3pid in invite_3pid_list:
             id_server = invite_3pid["id_server"]
-            id_access_token = invite_3pid.get("id_access_token")  # optional
+            id_access_token = invite_3pid["id_access_token"]
             address = invite_3pid["address"]
             medium = invite_3pid["medium"]
             # Note that do_3pid_invite can raise a  ShadowBanError, but this was
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index e726997d83..5d4adf5bfd 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -1382,7 +1382,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
         id_server: str,
         requester: Requester,
         txn_id: Optional[str],
-        id_access_token: Optional[str] = None,
+        id_access_token: str,
         prev_event_ids: Optional[List[str]] = None,
         depth: Optional[int] = None,
     ) -> Tuple[str, int]:
@@ -1397,7 +1397,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
             requester: The user making the request.
             txn_id: The transaction ID this is part of, or None if this is not
                 part of a transaction.
-            id_access_token: The optional identity server access token.
+            id_access_token: Identity server access token.
             depth: Override the depth used to order the event in the DAG.
             prev_event_ids: The event IDs to use as the prev events
                 Should normally be set to None, which will cause the depth to be calculated
@@ -1494,7 +1494,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
         room_id: str,
         user: UserID,
         txn_id: Optional[str],
-        id_access_token: Optional[str] = None,
+        id_access_token: str,
         prev_event_ids: Optional[List[str]] = None,
         depth: Optional[int] = None,
     ) -> Tuple[EventBase, int]:
diff --git a/synapse/rest/client/room.py b/synapse/rest/client/room.py
index 0e2834008e..0bca012535 100644
--- a/synapse/rest/client/room.py
+++ b/synapse/rest/client/room.py
@@ -17,6 +17,7 @@
 import logging
 import re
 from enum import Enum
+from http import HTTPStatus
 from typing import TYPE_CHECKING, Awaitable, Dict, List, Optional, Tuple
 from urllib import parse as urlparse
 
@@ -947,7 +948,16 @@ class RoomMembershipRestServlet(TransactionRestServlet):
             # cheekily send invalid bodies.
             content = {}
 
-        if membership_action == "invite" and self._has_3pid_invite_keys(content):
+        if membership_action == "invite" and all(
+            key in content for key in ("medium", "address")
+        ):
+            if not all(key in content for key in ("id_server", "id_access_token")):
+                raise SynapseError(
+                    HTTPStatus.BAD_REQUEST,
+                    "`id_server` and `id_access_token` are required when doing 3pid invite",
+                    Codes.MISSING_PARAM,
+                )
+
             try:
                 await self.room_member_handler.do_3pid_invite(
                     room_id,
@@ -957,7 +967,7 @@ class RoomMembershipRestServlet(TransactionRestServlet):
                     content["id_server"],
                     requester,
                     txn_id,
-                    content.get("id_access_token"),
+                    content["id_access_token"],
                 )
             except ShadowBanError:
                 # Pretend the request succeeded.
@@ -994,12 +1004,6 @@ class RoomMembershipRestServlet(TransactionRestServlet):
 
         return 200, return_value
 
-    def _has_3pid_invite_keys(self, content: JsonDict) -> bool:
-        for key in {"id_server", "medium", "address"}:
-            if key not in content:
-                return False
-        return True
-
     def on_PUT(
         self, request: SynapseRequest, room_id: str, membership_action: str, txn_id: str
     ) -> Awaitable[Tuple[int, JsonDict]]:
diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index 7435fd9130..9dd3c8d4bb 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -64,7 +64,6 @@ if TYPE_CHECKING:
 
 logger = logging.getLogger(__name__)
 
-
 # How often to run the background job to update the "recently accessed"
 # attribute of local and remote media.
 UPDATE_RECENTLY_ACCESSED_TS = 60 * 1000  # 1 minute
diff --git a/tests/rest/client/test_identity.py b/tests/rest/client/test_identity.py
index dc17c9d113..b0c8215744 100644
--- a/tests/rest/client/test_identity.py
+++ b/tests/rest/client/test_identity.py
@@ -25,7 +25,6 @@ from tests import unittest
 
 
 class IdentityTestCase(unittest.HomeserverTestCase):
-
     servlets = [
         synapse.rest.admin.register_servlets_for_client_rest_resource,
         room.register_servlets,
@@ -33,7 +32,6 @@ class IdentityTestCase(unittest.HomeserverTestCase):
     ]
 
     def make_homeserver(self, reactor: MemoryReactor, clock: Clock) -> HomeServer:
-
         config = self.default_config()
         config["enable_3pid_lookup"] = False
         self.hs = self.setup_test_homeserver(config=config)
@@ -54,6 +52,7 @@ class IdentityTestCase(unittest.HomeserverTestCase):
             "id_server": "testis",
             "medium": "email",
             "address": "test@example.com",
+            "id_access_token": tok,
         }
         request_url = ("/rooms/%s/invite" % (room_id)).encode("ascii")
         channel = self.make_request(
diff --git a/tests/rest/client/test_rooms.py b/tests/rest/client/test_rooms.py
index aa2f578441..c7eb88d33f 100644
--- a/tests/rest/client/test_rooms.py
+++ b/tests/rest/client/test_rooms.py
@@ -3461,3 +3461,21 @@ class ThreepidInviteTestCase(unittest.HomeserverTestCase):
 
         # Also check that it stopped before calling _make_and_store_3pid_invite.
         make_invite_mock.assert_called_once()
+
+    def test_400_missing_param_without_id_access_token(self) -> None:
+        """
+        Test that a 3pid invite request returns 400 M_MISSING_PARAM
+        if we do not include id_access_token.
+        """
+        channel = self.make_request(
+            method="POST",
+            path="/rooms/" + self.room_id + "/invite",
+            content={
+                "id_server": "example.com",
+                "medium": "email",
+                "address": "teresa@example.com",
+            },
+            access_token=self.tok,
+        )
+        self.assertEqual(channel.code, 400)
+        self.assertEqual(channel.json_body["errcode"], "M_MISSING_PARAM")
diff --git a/tests/rest/client/test_shadow_banned.py b/tests/rest/client/test_shadow_banned.py
index c50f034b34..c807a37bc2 100644
--- a/tests/rest/client/test_shadow_banned.py
+++ b/tests/rest/client/test_shadow_banned.py
@@ -97,7 +97,12 @@ class RoomTestCase(_ShadowBannedBase):
         channel = self.make_request(
             "POST",
             "/rooms/%s/invite" % (room_id,),
-            {"id_server": "test", "medium": "email", "address": "test@test.test"},
+            {
+                "id_server": "test",
+                "medium": "email",
+                "address": "test@test.test",
+                "id_access_token": "anytoken",
+            },
             access_token=self.banned_access_token,
         )
         self.assertEqual(200, channel.code, channel.result)