anonymousland-synapse/synapse/api/auth.py
Erik Johnston 4a1597f295 Fix bug in redaction auth.
This caused a 500 when sending a redaction due to a typo in a method
invocation.
2014-10-31 09:48:59 +00:00

524 lines
17 KiB
Python

# -*- coding: utf-8 -*-
# Copyright 2014 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.
"""This module contains classes for authenticating the user."""
from twisted.internet import defer
from synapse.api.constants import Membership, JoinRules
from synapse.api.errors import AuthError, StoreError, Codes, SynapseError
from synapse.api.events.room import (
RoomMemberEvent, RoomPowerLevelsEvent, RoomRedactionEvent,
RoomJoinRulesEvent, RoomOpsPowerLevelsEvent, InviteJoinEvent,
RoomCreateEvent,
)
from synapse.util.logutils import log_function
import logging
logger = logging.getLogger(__name__)
class Auth(object):
def __init__(self, hs):
self.hs = hs
self.store = hs.get_datastore()
@defer.inlineCallbacks
def check(self, event, snapshot, raises=False):
""" Checks if this event is correctly authed.
Returns:
True if the auth checks pass.
Raises:
AuthError if there was a problem authorising this event. This will
be raised only if raises=True.
"""
try:
if hasattr(event, "room_id"):
if event.old_state_events is None:
# Oh, we don't know what the state of the room was, so we
# are trusting that this is allowed (at least for now)
defer.returnValue(True)
if hasattr(event, "outlier") and event.outlier is True:
# TODO (erikj): Auth for outliers is done differently.
defer.returnValue(True)
is_state = hasattr(event, "state_key")
if event.type == RoomCreateEvent.TYPE:
# FIXME
defer.returnValue(True)
if event.type == RoomMemberEvent.TYPE:
self._can_replace_state(event)
allowed = self.is_membership_change_allowed(event)
if allowed:
logger.debug("Allowing! %s", event)
else:
logger.debug("Denying! %s", event)
defer.returnValue(allowed)
return
if not event.type == InviteJoinEvent.TYPE:
self.check_event_sender_in_room(event)
if is_state:
# TODO (erikj): This really only should be called for *new*
# state
yield self._can_add_state(event)
self._can_replace_state(event)
else:
yield self._can_send_event(event)
if event.type == RoomPowerLevelsEvent.TYPE:
self._check_power_levels(event)
if event.type == RoomRedactionEvent.TYPE:
self._check_redaction(event)
logger.debug("Allowing! %s", event)
defer.returnValue(True)
else:
raise AuthError(500, "Unknown event: %s" % event)
except AuthError as e:
logger.info("Event auth check failed on event %s with msg: %s",
event, e.msg)
logger.info("Denying! %s", event)
if raises:
raise e
defer.returnValue(False)
@defer.inlineCallbacks
def check_joined_room(self, room_id, user_id):
try:
member = yield self.store.get_room_member(
room_id=room_id,
user_id=user_id
)
self._check_joined_room(member, user_id, room_id)
defer.returnValue(member)
except AttributeError:
pass
defer.returnValue(None)
def check_event_sender_in_room(self, event):
key = (RoomMemberEvent.TYPE, event.user_id, )
member_event = event.state_events.get(key)
return self._check_joined_room(
member_event,
event.user_id,
event.room_id
)
def _check_joined_room(self, member, user_id, room_id):
if not member or member.membership != Membership.JOIN:
raise AuthError(403, "User %s not in room %s (%s)" % (
user_id, room_id, repr(member)
))
@log_function
def is_membership_change_allowed(self, event):
target_user_id = event.state_key
# get info about the caller
key = (RoomMemberEvent.TYPE, event.user_id, )
caller = event.old_state_events.get(key)
caller_in_room = caller and caller.membership == "join"
# get info about the target
key = (RoomMemberEvent.TYPE, target_user_id, )
target = event.old_state_events.get(key)
target_in_room = target and target.membership == "join"
membership = event.content["membership"]
key = (RoomJoinRulesEvent.TYPE, "", )
join_rule_event = event.old_state_events.get(key)
if join_rule_event:
join_rule = join_rule_event.content.get(
"join_rule", JoinRules.INVITE
)
else:
join_rule = JoinRules.INVITE
user_level = self._get_power_level_from_event_state(
event,
event.user_id,
)
ban_level, kick_level, redact_level = (
self._get_ops_level_from_event_state(
event
)
)
logger.debug(
"is_membership_change_allowed: %s",
{
"caller_in_room": caller_in_room,
"target_in_room": target_in_room,
"membership": membership,
"join_rule": join_rule,
"target_user_id": target_user_id,
"event.user_id": event.user_id,
}
)
if Membership.INVITE == membership:
# TODO (erikj): We should probably handle this more intelligently
# PRIVATE join rules.
# Invites are valid iff caller is in the room and target isn't.
if not caller_in_room: # caller isn't joined
raise AuthError(403, "You are not in room %s." % event.room_id)
elif target_in_room: # the target is already in the room.
raise AuthError(403, "%s is already in the room." %
target_user_id)
elif Membership.JOIN == membership:
# Joins are valid iff caller == target and they were:
# invited: They are accepting the invitation
# joined: It's a NOOP
if event.user_id != target_user_id:
raise AuthError(403, "Cannot force another user to join.")
elif join_rule == JoinRules.PUBLIC:
pass
elif join_rule == JoinRules.INVITE:
if not caller_in_room:
raise AuthError(403, "You are not invited to this room.")
else:
# TODO (erikj): may_join list
# TODO (erikj): private rooms
raise AuthError(403, "You are not allowed to join this room")
elif Membership.LEAVE == membership:
# TODO (erikj): Implement kicks.
if not caller_in_room: # trying to leave a room you aren't joined
raise AuthError(403, "You are not in room %s." % event.room_id)
elif target_user_id != event.user_id:
if kick_level:
kick_level = int(kick_level)
else:
kick_level = 50 # FIXME (erikj): What should we do here?
if user_level < kick_level:
raise AuthError(
403, "You cannot kick user %s." % target_user_id
)
elif Membership.BAN == membership:
if ban_level:
ban_level = int(ban_level)
else:
ban_level = 50 # FIXME (erikj): What should we do here?
if user_level < ban_level:
raise AuthError(403, "You don't have permission to ban")
else:
raise AuthError(500, "Unknown membership %s" % membership)
return True
def _get_power_level_from_event_state(self, event, user_id):
key = (RoomPowerLevelsEvent.TYPE, "", )
power_level_event = event.old_state_events.get(key)
level = None
if power_level_event:
level = power_level_event.content.get(user_id)
if not level:
level = power_level_event.content.get("default", 0)
return level
def _get_ops_level_from_event_state(self, event):
key = (RoomOpsPowerLevelsEvent.TYPE, "", )
ops_event = event.old_state_events.get(key)
if ops_event:
return (
ops_event.content.get("ban_level"),
ops_event.content.get("kick_level"),
ops_event.content.get("redact_level"),
)
return None, None, None,
@defer.inlineCallbacks
def get_user_by_req(self, request):
""" Get a registered user's ID.
Args:
request - An HTTP request with an access_token query parameter.
Returns:
UserID : User ID object of the user making the request
Raises:
AuthError if no user by that token exists or the token is invalid.
"""
# Can optionally look elsewhere in the request (e.g. headers)
try:
access_token = request.args["access_token"][0]
user_info = yield self.get_user_by_token(access_token)
user = user_info["user"]
ip_addr = self.hs.get_ip_from_request(request)
user_agent = request.requestHeaders.getRawHeaders(
"User-Agent",
default=[""]
)[0]
if user and access_token and ip_addr:
self.store.insert_client_ip(
user=user,
access_token=access_token,
device_id=user_info["device_id"],
ip=ip_addr,
user_agent=user_agent
)
defer.returnValue(user)
except KeyError:
raise AuthError(403, "Missing access token.")
@defer.inlineCallbacks
def get_user_by_token(self, token):
""" Get a registered user's ID.
Args:
token (str): The access token to get the user by.
Returns:
dict : dict that includes the user, device_id, and whether the
user is a server admin.
Raises:
AuthError if no user by that token exists or the token is invalid.
"""
try:
ret = yield self.store.get_user_by_token(token=token)
if not ret:
raise StoreError()
user_info = {
"admin": bool(ret.get("admin", False)),
"device_id": ret.get("device_id"),
"user": self.hs.parse_userid(ret.get("name")),
}
defer.returnValue(user_info)
except StoreError:
raise AuthError(403, "Unrecognised access token.",
errcode=Codes.UNKNOWN_TOKEN)
def is_server_admin(self, user):
return self.store.is_server_admin(user)
@defer.inlineCallbacks
@log_function
def _can_send_event(self, event):
send_level = yield self.store.get_send_event_level(event.room_id)
if send_level:
send_level = int(send_level)
else:
send_level = 0
user_level = self._get_power_level_from_event_state(
event,
event.user_id,
)
if user_level:
user_level = int(user_level)
else:
user_level = 0
if user_level < send_level:
raise AuthError(
403, "You don't have permission to post to the room"
)
defer.returnValue(True)
@defer.inlineCallbacks
def _can_add_state(self, event):
add_level = yield self.store.get_add_state_level(event.room_id)
if not add_level:
defer.returnValue(True)
add_level = int(add_level)
user_level = self._get_power_level_from_event_state(
event,
event.user_id,
)
user_level = int(user_level)
if user_level < add_level:
raise AuthError(
403, "You don't have permission to add state to the room"
)
defer.returnValue(True)
def _can_replace_state(self, event):
user_level = self._get_power_level_from_event_state(
event,
event.user_id,
)
if user_level:
user_level = int(user_level)
else:
user_level = 0
logger.debug(
"Checking power level for %s, %s", event.user_id, user_level
)
key = (event.type, event.state_key, )
current_state = event.old_state_events.get(key)
if current_state and hasattr(current_state, "required_power_level"):
req = current_state.required_power_level
logger.debug("Checked power level for %s, %s", event.user_id, req)
if user_level < req:
raise AuthError(
403,
"You don't have permission to change that state"
)
def _check_redaction(self, event):
user_level = self._get_power_level_from_event_state(
event,
event.user_id,
)
if user_level:
user_level = int(user_level)
else:
user_level = 0
_, _, redact_level = self._get_ops_level_from_event_state(
event
)
if not redact_level:
redact_level = 50
if user_level < redact_level:
raise AuthError(
403,
"You don't have permission to redact events"
)
def _check_power_levels(self, event):
for k, v in event.content.items():
if k == "default":
continue
# FIXME (erikj): We don't want hsob_Ts in content.
if k == "hsob_ts":
continue
try:
self.hs.parse_userid(k)
except:
raise SynapseError(400, "Not a valid user_id: %s" % (k,))
try:
int(v)
except:
raise SynapseError(400, "Not a valid power level: %s" % (v,))
key = (event.type, event.state_key, )
current_state = event.old_state_events.get(key)
if not current_state:
return
else:
current_state = current_state[0]
user_level = self._get_power_level_from_event_state(
event,
event.user_id,
)
if user_level:
user_level = int(user_level)
else:
user_level = 0
old_list = current_state.content
# FIXME (erikj)
old_people = {k: v for k, v in old_list.items() if k.startswith("@")}
new_people = {
k: v for k, v in event.content.items()
if k.startswith("@")
}
removed = set(old_people.keys()) - set(new_people.keys())
added = set(new_people.keys()) - set(old_people.keys())
same = set(old_people.keys()) & set(new_people.keys())
for r in removed:
if int(old_list[r]) > user_level:
raise AuthError(
403,
"You don't have permission to remove user: %s" % (r, )
)
for n in added:
if int(event.content[n]) > user_level:
raise AuthError(
403,
"You don't have permission to add ops level greater "
"than your own"
)
for s in same:
if int(event.content[s]) != int(old_list[s]):
if int(event.content[s]) > user_level:
raise AuthError(
403,
"You don't have permission to add ops level greater "
"than your own"
)
if "default" in old_list:
old_default = int(old_list["default"])
if old_default > user_level:
raise AuthError(
403,
"You don't have permission to add ops level greater than "
"your own"
)
if "default" in event.content:
new_default = int(event.content["default"])
if new_default > user_level:
raise AuthError(
403,
"You don't have permission to add ops level greater "
"than your own"
)