diff --git a/changelog.d/10933.bugfix b/changelog.d/10933.bugfix
new file mode 100644
index 0000000000000000000000000000000000000000..e0694fea22f58d9ee6269f12f28c7462c9ececd7
--- /dev/null
+++ b/changelog.d/10933.bugfix
@@ -0,0 +1 @@
+Fix a bug introduced in Synapse v1.40.0 where changing a user's display name or avatar in a restricted room would cause an authentication error.
diff --git a/synapse/api/constants.py b/synapse/api/constants.py
index 39fd9954d507b6736996e35818d8a7d086260bab..a31f037748a3767a4f42eaab8bfe3389b1f7c976 100644
--- a/synapse/api/constants.py
+++ b/synapse/api/constants.py
@@ -217,6 +217,9 @@ class EventContentFields:
# For "marker" events
MSC2716_MARKER_INSERTION = "org.matrix.msc2716.marker.insertion"
+ # The authorising user for joining a restricted room.
+ AUTHORISING_USER = "join_authorised_via_users_server"
+
class RoomTypes:
"""Understood values of the room_type field of m.room.create events."""
diff --git a/synapse/event_auth.py b/synapse/event_auth.py
index fc50a0e71a7dbd2c544a20e66d5b0b68debfa97f..650402836ce6abd061330b67dfca46e11383eaca 100644
--- a/synapse/event_auth.py
+++ b/synapse/event_auth.py
@@ -115,11 +115,11 @@ def check(
is_invite_via_allow_rule = (
event.type == EventTypes.Member
and event.membership == Membership.JOIN
- and "join_authorised_via_users_server" in event.content
+ and EventContentFields.AUTHORISING_USER in event.content
)
if is_invite_via_allow_rule:
authoriser_domain = get_domain_from_id(
- event.content["join_authorised_via_users_server"]
+ event.content[EventContentFields.AUTHORISING_USER]
)
if not event.signatures.get(authoriser_domain):
raise AuthError(403, "Event not signed by authorising server")
@@ -381,7 +381,9 @@ def _is_membership_change_allowed(
# Note that if the caller is in the room or invited, then they do
# not need to meet the allow rules.
if not caller_in_room and not caller_invited:
- authorising_user = event.content.get("join_authorised_via_users_server")
+ authorising_user = event.content.get(
+ EventContentFields.AUTHORISING_USER
+ )
if authorising_user is None:
raise AuthError(403, "Join event is missing authorising user.")
@@ -836,10 +838,10 @@ def auth_types_for_event(
auth_types.add(key)
if room_version.msc3083_join_rules and membership == Membership.JOIN:
- if "join_authorised_via_users_server" in event.content:
+ if EventContentFields.AUTHORISING_USER in event.content:
key = (
EventTypes.Member,
- event.content["join_authorised_via_users_server"],
+ event.content[EventContentFields.AUTHORISING_USER],
)
auth_types.add(key)
diff --git a/synapse/events/utils.py b/synapse/events/utils.py
index f86113a448c3e1275d092fb656db10e58c369776..38fccd1efcf52a3cb8a886eb23fa83863112ada5 100644
--- a/synapse/events/utils.py
+++ b/synapse/events/utils.py
@@ -105,7 +105,7 @@ def prune_event_dict(room_version: RoomVersion, event_dict: dict) -> dict:
if event_type == EventTypes.Member:
add_fields("membership")
if room_version.msc3375_redaction_rules:
- add_fields("join_authorised_via_users_server")
+ add_fields(EventContentFields.AUTHORISING_USER)
elif event_type == EventTypes.Create:
# MSC2176 rules state that create events cannot be redacted.
if room_version.msc2176_redaction_rules:
diff --git a/synapse/federation/federation_base.py b/synapse/federation/federation_base.py
index 024e440ff4013abfabaaabcf6a755fdf44279c60..0cd424e12aa153dda77d26624f377db1caeece34 100644
--- a/synapse/federation/federation_base.py
+++ b/synapse/federation/federation_base.py
@@ -15,7 +15,7 @@
import logging
from collections import namedtuple
-from synapse.api.constants import MAX_DEPTH, EventTypes, Membership
+from synapse.api.constants import MAX_DEPTH, EventContentFields, EventTypes, Membership
from synapse.api.errors import Codes, SynapseError
from synapse.api.room_versions import EventFormatVersions, RoomVersion
from synapse.crypto.event_signing import check_event_content_hash
@@ -184,10 +184,10 @@ async def _check_sigs_on_pdu(
room_version.msc3083_join_rules
and pdu.type == EventTypes.Member
and pdu.membership == Membership.JOIN
- and "join_authorised_via_users_server" in pdu.content
+ and EventContentFields.AUTHORISING_USER in pdu.content
):
authorising_server = get_domain_from_id(
- pdu.content["join_authorised_via_users_server"]
+ pdu.content[EventContentFields.AUTHORISING_USER]
)
try:
await keyring.verify_event_for_server(
diff --git a/synapse/federation/federation_client.py b/synapse/federation/federation_client.py
index 584836c04ad19639f67d90c11919bbadc0850da0..2ab4dec88fe692167a677081430418961a287445 100644
--- a/synapse/federation/federation_client.py
+++ b/synapse/federation/federation_client.py
@@ -37,7 +37,7 @@ from typing import (
import attr
from prometheus_client import Counter
-from synapse.api.constants import EventTypes, Membership
+from synapse.api.constants import EventContentFields, EventTypes, Membership
from synapse.api.errors import (
CodeMessageException,
Codes,
@@ -875,9 +875,9 @@ class FederationClient(FederationBase):
# If the join is being authorised via allow rules, we need to send
# the /send_join back to the same server that was originally used
# with /make_join.
- if "join_authorised_via_users_server" in pdu.content:
+ if EventContentFields.AUTHORISING_USER in pdu.content:
destinations = [
- get_domain_from_id(pdu.content["join_authorised_via_users_server"])
+ get_domain_from_id(pdu.content[EventContentFields.AUTHORISING_USER])
]
return await self._try_destination_list(
diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index 638959cbecdbc4f4966c1849a141c2758dabab75..5f4383eebcd3c70acc35980e71b69aaa9cbd17f1 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -34,7 +34,7 @@ from twisted.internet import defer
from twisted.internet.abstract import isIPAddress
from twisted.python import failure
-from synapse.api.constants import EduTypes, EventTypes, Membership
+from synapse.api.constants import EduTypes, EventContentFields, EventTypes, Membership
from synapse.api.errors import (
AuthError,
Codes,
@@ -765,11 +765,11 @@ class FederationServer(FederationBase):
if (
room_version.msc3083_join_rules
and event.membership == Membership.JOIN
- and "join_authorised_via_users_server" in event.content
+ and EventContentFields.AUTHORISING_USER in event.content
):
# We can only authorise our own users.
authorising_server = get_domain_from_id(
- event.content["join_authorised_via_users_server"]
+ event.content[EventContentFields.AUTHORISING_USER]
)
if authorising_server != self.server_name:
raise SynapseError(
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index b17ef2a9a1044789b98da4b97a8b55598696ac32..adbd150e46e57b33302b521940c9450336e1c937 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -27,7 +27,12 @@ from unpaddedbase64 import decode_base64
from twisted.internet import defer
from synapse import event_auth
-from synapse.api.constants import EventTypes, Membership, RejectedReason
+from synapse.api.constants import (
+ EventContentFields,
+ EventTypes,
+ Membership,
+ RejectedReason,
+)
from synapse.api.errors import (
AuthError,
CodeMessageException,
@@ -712,7 +717,7 @@ class FederationHandler(BaseHandler):
if include_auth_user_id:
event_content[
- "join_authorised_via_users_server"
+ EventContentFields.AUTHORISING_USER
] = await self._event_auth_handler.get_user_which_could_invite(
room_id,
state_ids,
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 1a56c82fbd9e2cdb60d774333e71d02341629f92..afa7e4727dc487b2326c6700426bd3bad100979e 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -573,6 +573,14 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
errcode=Codes.BAD_JSON,
)
+ # The event content should *not* include the authorising user as
+ # it won't be properly signed. Strip it out since it might come
+ # back from a client updating a display name / avatar.
+ #
+ # This only applies to restricted rooms, but there should be no reason
+ # for a client to include it. Unconditionally remove it.
+ content.pop(EventContentFields.AUTHORISING_USER, None)
+
effective_membership_state = action
if action in ["kick", "unban"]:
effective_membership_state = "leave"
@@ -939,7 +947,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
# be included in the event content in order to efficiently validate
# the event.
content[
- "join_authorised_via_users_server"
+ EventContentFields.AUTHORISING_USER
] = await self.event_auth_handler.get_user_which_could_invite(
room_id,
current_state_ids,
diff --git a/tests/events/test_utils.py b/tests/events/test_utils.py
index 5446fda5e7a3d8c9d3785bacae82062d03d9a5dd..1dea09e4800d59171e3d8b12d52f7d83ab6d3346 100644
--- a/tests/events/test_utils.py
+++ b/tests/events/test_utils.py
@@ -12,6 +12,7 @@
# See the License for the specific language governing permissions and
# limitations under the License.
+from synapse.api.constants import EventContentFields
from synapse.api.room_versions import RoomVersions
from synapse.events import make_event_from_dict
from synapse.events.utils import (
@@ -352,7 +353,7 @@ class PruneEventTestCase(unittest.TestCase):
"event_id": "$test:domain",
"content": {
"membership": "join",
- "join_authorised_via_users_server": "@user:domain",
+ EventContentFields.AUTHORISING_USER: "@user:domain",
"other_key": "stripped",
},
},
@@ -372,7 +373,7 @@ class PruneEventTestCase(unittest.TestCase):
"type": "m.room.member",
"content": {
"membership": "join",
- "join_authorised_via_users_server": "@user:domain",
+ EventContentFields.AUTHORISING_USER: "@user:domain",
"other_key": "stripped",
},
},
@@ -380,7 +381,7 @@ class PruneEventTestCase(unittest.TestCase):
"type": "m.room.member",
"content": {
"membership": "join",
- "join_authorised_via_users_server": "@user:domain",
+ EventContentFields.AUTHORISING_USER: "@user:domain",
},
"signatures": {},
"unsigned": {},
diff --git a/tests/test_event_auth.py b/tests/test_event_auth.py
index 6ebd01bcbe781d95c1d85c05b598c6335118c3e2..1a4d078780ecef9558f1a9505cfbfac3ba4e8fbf 100644
--- a/tests/test_event_auth.py
+++ b/tests/test_event_auth.py
@@ -16,6 +16,7 @@ import unittest
from typing import Optional
from synapse import event_auth
+from synapse.api.constants import EventContentFields
from synapse.api.errors import AuthError
from synapse.api.room_versions import RoomVersions
from synapse.events import EventBase, make_event_from_dict
@@ -380,7 +381,7 @@ class EventAuthTestCase(unittest.TestCase):
authorised_join_event = _join_event(
pleb,
additional_content={
- "join_authorised_via_users_server": "@creator:example.com"
+ EventContentFields.AUTHORISING_USER: "@creator:example.com"
},
)
event_auth.check(
@@ -404,7 +405,7 @@ class EventAuthTestCase(unittest.TestCase):
_join_event(
pleb,
additional_content={
- "join_authorised_via_users_server": "@inviter:foo.test"
+ EventContentFields.AUTHORISING_USER: "@inviter:foo.test"
},
),
pl_auth_events,
@@ -431,7 +432,7 @@ class EventAuthTestCase(unittest.TestCase):
_join_event(
pleb,
additional_content={
- "join_authorised_via_users_server": "@other:example.com"
+ EventContentFields.AUTHORISING_USER: "@other:example.com"
},
),
auth_events,
@@ -448,7 +449,7 @@ class EventAuthTestCase(unittest.TestCase):
"join",
sender=creator,
additional_content={
- "join_authorised_via_users_server": "@inviter:foo.test"
+ EventContentFields.AUTHORISING_USER: "@inviter:foo.test"
},
),
auth_events,