MatrixSynapse/synapse/handlers/directory.py

519 lines
19 KiB
Python

# Copyright 2014-2016 OpenMarket Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# 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 logging
import string
from typing import TYPE_CHECKING, Iterable, List, Optional
from synapse.api.constants import MAX_ALIAS_LENGTH, EventTypes
from synapse.api.errors import (
AuthError,
CodeMessageException,
Codes,
NotFoundError,
RequestSendFailed,
ShadowBanError,
StoreError,
SynapseError,
)
from synapse.appservice import ApplicationService
from synapse.storage.databases.main.directory import RoomAliasMapping
from synapse.types import JsonDict, Requester, RoomAlias, UserID, get_domain_from_id
if TYPE_CHECKING:
from synapse.server import HomeServer
logger = logging.getLogger(__name__)
class DirectoryHandler:
def __init__(self, hs: "HomeServer"):
self.auth = hs.get_auth()
self.hs = hs
self.state = hs.get_state_handler()
self.appservice_handler = hs.get_application_service_handler()
self.event_creation_handler = hs.get_event_creation_handler()
self.store = hs.get_datastores().main
self.config = hs.config
self.enable_room_list_search = hs.config.roomdirectory.enable_room_list_search
self.require_membership = hs.config.server.require_membership_for_aliases
self.third_party_event_rules = hs.get_third_party_event_rules()
self.server_name = hs.hostname
self.federation = hs.get_federation_client()
hs.get_federation_registry().register_query_handler(
"directory", self.on_directory_query
)
self.spam_checker = hs.get_spam_checker()
async def _create_association(
self,
room_alias: RoomAlias,
room_id: str,
servers: Optional[Iterable[str]] = None,
creator: Optional[str] = None,
) -> None:
# general association creation for both human users and app services
for wchar in string.whitespace:
if wchar in room_alias.localpart:
raise SynapseError(400, "Invalid characters in room alias")
if not self.hs.is_mine(room_alias):
raise SynapseError(400, "Room alias must be local")
# TODO(erikj): Change this.
# TODO(erikj): Add transactions.
# TODO(erikj): Check if there is a current association.
if not servers:
users = await self.store.get_users_in_room(room_id)
servers = {get_domain_from_id(u) for u in users}
if not servers:
raise SynapseError(400, "Failed to get server list")
await self.store.create_room_alias_association(
room_alias, room_id, servers, creator=creator
)
async def create_association(
self,
requester: Requester,
room_alias: RoomAlias,
room_id: str,
servers: Optional[List[str]] = None,
check_membership: bool = True,
) -> None:
"""Attempt to create a new alias
Args:
requester
room_alias
room_id
servers: Iterable of servers that others servers should try and join via
check_membership: Whether to check if the user is in the room
before the alias can be set (if the server's config requires it).
"""
user_id = requester.user.to_string()
room_alias_str = room_alias.to_string()
if len(room_alias_str) > MAX_ALIAS_LENGTH:
raise SynapseError(
400,
"Can't create aliases longer than %s characters" % MAX_ALIAS_LENGTH,
Codes.INVALID_PARAM,
)
service = requester.app_service
if service:
if not service.is_interested_in_alias(room_alias_str):
raise SynapseError(
400,
"This application service has not reserved this kind of alias.",
errcode=Codes.EXCLUSIVE,
)
else:
# Server admins are not subject to the same constraints as normal
# users when creating an alias (e.g. being in the room).
is_admin = await self.auth.is_server_admin(requester.user)
if (self.require_membership and check_membership) and not is_admin:
rooms_for_user = await self.store.get_rooms_for_user(user_id)
if room_id not in rooms_for_user:
raise AuthError(
403, "You must be in the room to create an alias for it"
)
if not await self.spam_checker.user_may_create_room_alias(
user_id, room_alias
):
raise AuthError(403, "This user is not permitted to create this alias")
if not self.config.roomdirectory.is_alias_creation_allowed(
user_id, room_id, room_alias_str
):
# Let's just return a generic message, as there may be all sorts of
# reasons why we said no. TODO: Allow configurable error messages
# per alias creation rule?
raise SynapseError(403, "Not allowed to create alias")
can_create = self.can_modify_alias(room_alias, user_id=user_id)
if not can_create:
raise AuthError(
400,
"This alias is reserved by an application service.",
errcode=Codes.EXCLUSIVE,
)
await self._create_association(room_alias, room_id, servers, creator=user_id)
async def delete_association(
self, requester: Requester, room_alias: RoomAlias
) -> str:
"""Remove an alias from the directory
(this is only meant for human users; AS users should call
delete_appservice_association)
Args:
requester
room_alias
Returns:
room id that the alias used to point to
Raises:
NotFoundError: if the alias doesn't exist
AuthError: if the user doesn't have perms to delete the alias (ie, the user
is neither the creator of the alias, nor a server admin.
SynapseError: if the alias belongs to an AS
"""
user_id = requester.user.to_string()
try:
can_delete = await self._user_can_delete_alias(room_alias, user_id)
except StoreError as e:
if e.code == 404:
raise NotFoundError("Unknown room alias")
raise
if not can_delete:
raise AuthError(403, "You don't have permission to delete the alias.")
can_delete = self.can_modify_alias(room_alias, user_id=user_id)
if not can_delete:
raise SynapseError(
400,
"This alias is reserved by an application service.",
errcode=Codes.EXCLUSIVE,
)
room_id = await self._delete_association(room_alias)
if room_id is None:
# It's possible someone else deleted the association after the
# checks above, but before we did the deletion.
raise NotFoundError("Unknown room alias")
try:
await self._update_canonical_alias(requester, user_id, room_id, room_alias)
except ShadowBanError as e:
logger.info("Failed to update alias events due to shadow-ban: %s", e)
except AuthError as e:
logger.info("Failed to update alias events: %s", e)
return room_id
async def delete_appservice_association(
self, service: ApplicationService, room_alias: RoomAlias
) -> None:
if not service.is_interested_in_alias(room_alias.to_string()):
raise SynapseError(
400,
"This application service has not reserved this kind of alias",
errcode=Codes.EXCLUSIVE,
)
await self._delete_association(room_alias)
async def _delete_association(self, room_alias: RoomAlias) -> Optional[str]:
if not self.hs.is_mine(room_alias):
raise SynapseError(400, "Room alias must be local")
room_id = await self.store.delete_room_alias(room_alias)
return room_id
async def get_association(self, room_alias: RoomAlias) -> JsonDict:
room_id = None
if self.hs.is_mine(room_alias):
result: Optional[
RoomAliasMapping
] = await self.get_association_from_room_alias(room_alias)
if result:
room_id = result.room_id
servers = result.servers
else:
try:
fed_result: Optional[JsonDict] = await self.federation.make_query(
destination=room_alias.domain,
query_type="directory",
args={"room_alias": room_alias.to_string()},
retry_on_dns_fail=False,
ignore_backoff=True,
)
except RequestSendFailed:
raise SynapseError(502, "Failed to fetch alias")
except CodeMessageException as e:
logging.warning("Error retrieving alias")
if e.code == 404:
fed_result = None
else:
raise SynapseError(502, "Failed to fetch alias")
if fed_result and "room_id" in fed_result and "servers" in fed_result:
room_id = fed_result["room_id"]
servers = fed_result["servers"]
if not room_id:
raise SynapseError(
404,
"Room alias %s not found" % (room_alias.to_string(),),
Codes.NOT_FOUND,
)
users = await self.store.get_users_in_room(room_id)
extra_servers = {get_domain_from_id(u) for u in users}
servers_set = set(extra_servers) | set(servers)
# If this server is in the list of servers, return it first.
if self.server_name in servers_set:
servers = [self.server_name] + [
s for s in servers_set if s != self.server_name
]
else:
servers = list(servers_set)
return {"room_id": room_id, "servers": servers}
async def on_directory_query(self, args: JsonDict) -> JsonDict:
room_alias = RoomAlias.from_string(args["room_alias"])
if not self.hs.is_mine(room_alias):
raise SynapseError(400, "Room Alias is not hosted on this homeserver")
result = await self.get_association_from_room_alias(room_alias)
if result is not None:
return {"room_id": result.room_id, "servers": result.servers}
else:
raise SynapseError(
404,
"Room alias %r not found" % (room_alias.to_string(),),
Codes.NOT_FOUND,
)
async def _update_canonical_alias(
self, requester: Requester, user_id: str, room_id: str, room_alias: RoomAlias
) -> None:
"""
Send an updated canonical alias event if the removed alias was set as
the canonical alias or listed in the alt_aliases field.
Raises:
ShadowBanError if the requester has been shadow-banned.
"""
alias_event = await self.state.get_current_state(
room_id, EventTypes.CanonicalAlias, ""
)
# There is no canonical alias, nothing to do.
if not alias_event:
return
# Obtain a mutable version of the event content.
content = dict(alias_event.content)
send_update = False
# Remove the alias property if it matches the removed alias.
alias_str = room_alias.to_string()
if alias_event.content.get("alias", "") == alias_str:
send_update = True
content.pop("alias", "")
# Filter the alt_aliases property for the removed alias. Note that the
# value is not modified if alt_aliases is of an unexpected form.
alt_aliases = content.get("alt_aliases")
if isinstance(alt_aliases, (list, tuple)) and alias_str in alt_aliases:
send_update = True
alt_aliases = [alias for alias in alt_aliases if alias != alias_str]
if alt_aliases:
content["alt_aliases"] = alt_aliases
else:
del content["alt_aliases"]
if send_update:
await self.event_creation_handler.create_and_send_nonmember_event(
requester,
{
"type": EventTypes.CanonicalAlias,
"state_key": "",
"room_id": room_id,
"sender": user_id,
"content": content,
},
ratelimit=False,
)
async def get_association_from_room_alias(
self, room_alias: RoomAlias
) -> Optional[RoomAliasMapping]:
result = await self.store.get_association_from_room_alias(room_alias)
if not result:
# Query AS to see if it exists
as_handler = self.appservice_handler
result = await as_handler.query_room_alias_exists(room_alias)
return result
def can_modify_alias(self, alias: RoomAlias, user_id: Optional[str] = None) -> bool:
# Any application service "interested" in an alias they are regexing on
# can modify the alias.
# Users can only modify the alias if ALL the interested services have
# non-exclusive locks on the alias (or there are no interested services)
services = self.store.get_app_services()
interested_services = [
s for s in services if s.is_interested_in_alias(alias.to_string())
]
for service in interested_services:
if user_id == service.sender:
# this user IS the app service so they can do whatever they like
return True
elif service.is_exclusive_alias(alias.to_string()):
# another service has an exclusive lock on this alias.
return False
# either no interested services, or no service with an exclusive lock
return True
async def _user_can_delete_alias(self, alias: RoomAlias, user_id: str) -> bool:
"""Determine whether a user can delete an alias.
One of the following must be true:
1. The user created the alias.
2. The user is a server administrator.
3. The user has a power-level sufficient to send a canonical alias event
for the current room.
"""
creator = await self.store.get_room_alias_creator(alias.to_string())
if creator == user_id:
return True
# Resolve the alias to the corresponding room.
room_mapping = await self.get_association(alias)
room_id = room_mapping["room_id"]
if not room_id:
return False
return await self.auth.check_can_change_room_list(
room_id, UserID.from_string(user_id)
)
async def edit_published_room_list(
self, requester: Requester, room_id: str, visibility: str
) -> None:
"""Edit the entry of the room in the published room list.
requester
room_id
visibility: "public" or "private"
"""
user_id = requester.user.to_string()
if not await self.spam_checker.user_may_publish_room(user_id, room_id):
raise AuthError(
403, "This user is not permitted to publish rooms to the room list"
)
if requester.is_guest:
raise AuthError(403, "Guests cannot edit the published room list")
if visibility not in ["public", "private"]:
raise SynapseError(400, "Invalid visibility setting")
if visibility == "public" and not self.enable_room_list_search:
# The room list has been disabled.
raise AuthError(
403, "This user is not permitted to publish rooms to the room list"
)
room = await self.store.get_room(room_id)
if room is None:
raise SynapseError(400, "Unknown room")
can_change_room_list = await self.auth.check_can_change_room_list(
room_id, requester.user
)
if not can_change_room_list:
raise AuthError(
403,
"This server requires you to be a moderator in the room to"
" edit its room list entry",
)
making_public = visibility == "public"
if making_public:
room_aliases = await self.store.get_aliases_for_room(room_id)
canonical_alias = await self.store.get_canonical_alias_for_room(room_id)
if canonical_alias:
room_aliases.append(canonical_alias)
if not self.config.roomdirectory.is_publishing_room_allowed(
user_id, room_id, room_aliases
):
# Let's just return a generic message, as there may be all sorts of
# reasons why we said no. TODO: Allow configurable error messages
# per alias creation rule?
raise SynapseError(403, "Not allowed to publish room")
# Check if publishing is blocked by a third party module
allowed_by_third_party_rules = await (
self.third_party_event_rules.check_visibility_can_be_modified(
room_id, visibility
)
)
if not allowed_by_third_party_rules:
raise SynapseError(403, "Not allowed to publish room")
await self.store.set_room_is_public(room_id, making_public)
async def edit_published_appservice_room_list(
self, appservice_id: str, network_id: str, room_id: str, visibility: str
) -> None:
"""Add or remove a room from the appservice/network specific public
room list.
Args:
appservice_id: ID of the appservice that owns the list
network_id: The ID of the network the list is associated with
room_id
visibility: either "public" or "private"
"""
if visibility not in ["public", "private"]:
raise SynapseError(400, "Invalid visibility setting")
await self.store.set_room_is_public_appservice(
room_id, appservice_id, network_id, visibility == "public"
)
async def get_aliases_for_room(
self, requester: Requester, room_id: str
) -> List[str]:
"""
Get a list of the aliases that currently point to this room on this server
"""
# allow access to server admins and current members of the room
is_admin = await self.auth.is_server_admin(requester.user)
if not is_admin:
await self.auth.check_user_in_room_or_world_readable(
room_id, requester.user.to_string()
)
return await self.store.get_aliases_for_room(room_id)