diff --git a/synapse/api/constants.py b/synapse/api/constants.py
index 0860b75905..8547a63535 100644
--- a/synapse/api/constants.py
+++ b/synapse/api/constants.py
@@ -20,6 +20,9 @@
# the "depth" field on events is limited to 2**63 - 1
MAX_DEPTH = 2**63 - 1
+# the maximum length for a room alias is 255 characters
+MAX_ALIAS_LENGTH = 255
+
class Membership(object):
diff --git a/synapse/events/snapshot.py b/synapse/events/snapshot.py
index 368b5f6ae4..fa09c132a0 100644
--- a/synapse/events/snapshot.py
+++ b/synapse/events/snapshot.py
@@ -187,7 +187,9 @@ class EventContext(object):
Returns:
Deferred[dict[(str, str), str]|None]: Returns None if state_group
- is None, which happens when the associated event is an outlier.
+ is None, which happens when the associated event is an outlier.
+ Maps a (type, state_key) to the event ID of the state event matching
+ this tuple.
"""
if not self._fetching_state_deferred:
@@ -205,7 +207,9 @@ class EventContext(object):
Returns:
Deferred[dict[(str, str), str]|None]: Returns None if state_group
- is None, which happens when the associated event is an outlier.
+ is None, which happens when the associated event is an outlier.
+ Maps a (type, state_key) to the event ID of the state event matching
+ this tuple.
"""
if not self._fetching_state_deferred:
diff --git a/synapse/events/validator.py b/synapse/events/validator.py
index 514273c792..711af512b2 100644
--- a/synapse/events/validator.py
+++ b/synapse/events/validator.py
@@ -15,8 +15,8 @@
from six import string_types
-from synapse.api.constants import EventTypes, Membership
-from synapse.api.errors import SynapseError
+from synapse.api.constants import MAX_ALIAS_LENGTH, EventTypes, Membership
+from synapse.api.errors import Codes, SynapseError
from synapse.api.room_versions import EventFormatVersions
from synapse.types import EventID, RoomID, UserID
@@ -56,6 +56,17 @@ class EventValidator(object):
if not isinstance(getattr(event, s), string_types):
raise SynapseError(400, "'%s' not a string type" % (s,))
+ if event.type == EventTypes.Aliases:
+ if "aliases" in event.content:
+ for alias in event.content["aliases"]:
+ if len(alias) > MAX_ALIAS_LENGTH:
+ raise SynapseError(
+ 400,
+ ("Can't create aliases longer than"
+ " %d characters" % (MAX_ALIAS_LENGTH,)),
+ Codes.INVALID_PARAM,
+ )
+
def validate_builder(self, event):
"""Validates that the builder/event has roughly the right format. Only
checks values that we expect a proto event to have, rather than all the
diff --git a/synapse/handlers/directory.py b/synapse/handlers/directory.py
index 50c587aa61..a12f9508d8 100644
--- a/synapse/handlers/directory.py
+++ b/synapse/handlers/directory.py
@@ -19,7 +19,7 @@ import string
from twisted.internet import defer
-from synapse.api.constants import EventTypes
+from synapse.api.constants import MAX_ALIAS_LENGTH, EventTypes
from synapse.api.errors import (
AuthError,
CodeMessageException,
@@ -36,7 +36,6 @@ logger = logging.getLogger(__name__)
class DirectoryHandler(BaseHandler):
- MAX_ALIAS_LENGTH = 255
def __init__(self, hs):
super(DirectoryHandler, self).__init__(hs)
@@ -105,10 +104,10 @@ class DirectoryHandler(BaseHandler):
user_id = requester.user.to_string()
- if len(room_alias.to_string()) > self.MAX_ALIAS_LENGTH:
+ if len(room_alias.to_string()) > MAX_ALIAS_LENGTH:
raise SynapseError(
400,
- "Can't create aliases longer than %s characters" % self.MAX_ALIAS_LENGTH,
+ "Can't create aliases longer than %s characters" % MAX_ALIAS_LENGTH,
Codes.INVALID_PARAM,
)
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 224d34ef3a..e5afeadf68 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -228,6 +228,7 @@ class EventCreationHandler(object):
self.ratelimiter = hs.get_ratelimiter()
self.notifier = hs.get_notifier()
self.config = hs.config
+ self.require_membership_for_aliases = hs.config.require_membership_for_aliases
self.send_event_to_master = ReplicationSendEventRestServlet.make_client(hs)
@@ -336,6 +337,35 @@ class EventCreationHandler(object):
prev_events_and_hashes=prev_events_and_hashes,
)
+ # In an ideal world we wouldn't need the second part of this condition. However,
+ # this behaviour isn't spec'd yet, meaning we should be able to deactivate this
+ # behaviour. Another reason is that this code is also evaluated each time a new
+ # m.room.aliases event is created, which includes hitting a /directory route.
+ # Therefore not including this condition here would render the similar one in
+ # synapse.handlers.directory pointless.
+ if builder.type == EventTypes.Aliases and self.require_membership_for_aliases:
+ # Ideally we'd do the membership check in event_auth.check(), which
+ # describes a spec'd algorithm for authenticating events received over
+ # federation as well as those created locally. As of room v3, aliases events
+ # can be created by users that are not in the room, therefore we have to
+ # tolerate them in event_auth.check().
+ prev_state_ids = yield context.get_prev_state_ids(self.store)
+ prev_event_id = prev_state_ids.get((EventTypes.Member, event.sender))
+ prev_event = yield self.store.get_event(prev_event_id, allow_none=True)
+ if not prev_event or prev_event.membership != Membership.JOIN:
+ logger.warning(
+ ("Attempt to send `m.room.aliases` in room %s by user %s but"
+ " membership is %s"),
+ event.room_id,
+ event.sender,
+ prev_event.membership if prev_event else None,
+ )
+
+ raise AuthError(
+ 403,
+ "You must be in the room to create an alias for it",
+ )
+
self.validator.validate_new(event)
defer.returnValue((event, context))
|
