# -*- 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, RoomCreateEvent, RoomAliasesEvent,
)
from synapse.util.logutils import log_function
from syutil.base64util import encode_base64
import logging
logger = logging.getLogger(__name__)
class Auth(object):
def __init__(self, hs):
self.hs = hs
self.store = hs.get_datastore()
self.state = hs.get_state_handler()
def check(self, event, 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)
logger.warn("Trusting event: %s", event.event_id)
return True
if hasattr(event, "outlier") and event.outlier is True:
# TODO (erikj): Auth for outliers is done differently.
return True
if event.type == RoomCreateEvent.TYPE:
# FIXME
return True
# FIXME: Temp hack
if event.type == RoomAliasesEvent.TYPE:
return True
if event.type == RoomMemberEvent.TYPE:
allowed = self.is_membership_change_allowed(event)
if allowed:
logger.debug("Allowing! %s", event)
else:
logger.debug("Denying! %s", event)
return allowed
self.check_event_sender_in_room(event)
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)
return 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
return 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)
@defer.inlineCallbacks
def check_host_in_room(self, room_id, host):
curr_state = yield self.state.get_current_state(room_id)
for event in curr_state:
if event.type == RoomMemberEvent.TYPE:
try:
if self.hs.parse_userid(event.state_key).domain != host:
continue
except:
logger.warn("state_key not user_id: %s", event.state_key)
continue
if event.content["membership"] == Membership.JOIN:
defer.returnValue(True)
defer.returnValue(False)
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):
membership = event.content["membership"]
# Check if this is the room creator joining:
if len(event.prev_events) == 1 and Membership.JOIN == membership:
# Get room creation event:
key = (RoomCreateEvent.TYPE, "", )
create = event.old_state_events.get(key)
if event.prev_events[0][0] == create.event_id:
if create.content["creator"] == event.state_key:
return True
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 == Membership.JOIN
caller_invited = caller and caller.membership == Membership.INVITE
# 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 == Membership.JOIN
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,
"caller_invited": caller_invited,
"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 and not caller_invited:
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("users", {}).get(user_id)
if not level:
level = power_level_event.content.get("users_default", 0)
else:
key = (RoomCreateEvent.TYPE, "", )
create_event = event.old_state_events.get(key)
if (create_event is not None and
create_event.content["creator"] == user_id):
return 100
return level
def _get_ops_level_from_event_state(self, event):
key = (RoomPowerLevelsEvent.TYPE, "", )
power_level_event = event.old_state_events.get(key)
if power_level_event:
return (
power_level_event.content.get("ban", 50),
power_level_event.content.get("kick", 50),
power_level_event.content.get("redact", 50),
)
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:
yield 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
def add_auth_events(self, event):
if event.type == RoomCreateEvent.TYPE:
event.auth_events = []
return
auth_events = []
key = (RoomPowerLevelsEvent.TYPE, "", )
power_level_event = event.old_state_events.get(key)
if power_level_event:
auth_events.append(power_level_event.event_id)
key = (RoomJoinRulesEvent.TYPE, "", )
join_rule_event = event.old_state_events.get(key)
key = (RoomMemberEvent.TYPE, event.user_id, )
member_event = event.old_state_events.get(key)
if join_rule_event:
join_rule = join_rule_event.content.get("join_rule")
is_public = join_rule == JoinRules.PUBLIC if join_rule else False
else:
is_public = False
if event.type == RoomMemberEvent.TYPE:
e_type = event.content["membership"]
if e_type in [Membership.JOIN, Membership.INVITE]:
if join_rule_event:
auth_events.append(join_rule_event.event_id)
if member_event and not is_public:
auth_events.append(member_event.event_id)
elif member_event:
if member_event.content["membership"] == Membership.JOIN:
auth_events.append(member_event.event_id)
hashes = yield self.store.get_event_reference_hashes(
auth_events
)
hashes = [
{
k: encode_base64(v) for k, v in h.items()
if k == "sha256"
}
for h in hashes
]
event.auth_events = zip(auth_events, hashes)
@log_function
def _can_send_event(self, event):
key = (RoomPowerLevelsEvent.TYPE, "", )
send_level_event = event.old_state_events.get(key)
send_level = None
if send_level_event:
send_level = send_level_event.content.get("events", {}).get(
event.type
)
if not send_level:
if hasattr(event, "state_key"):
send_level = send_level_event.content.get(
"state_default", 50
)
else:
send_level = send_level_event.content.get(
"events_default", 0
)
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 that to the room. " +
"user_level (%d) < send_level (%d)" % (user_level, send_level)
)
# Check state_key
if hasattr(event, "state_key"):
if not event.state_key.startswith("_"):
if event.state_key.startswith("@"):
if event.state_key != event.user_id:
raise AuthError(
403,
"You are not allowed to set others state"
)
else:
sender_domain = self.hs.parse_userid(
event.user_id
).domain
if sender_domain != event.state_key:
raise AuthError(
403,
"You are not allowed to set others state"
)
return True
def _check_redaction(self, event):
user_level = self._get_power_level_from_event_state(
event,
event.user_id,
)
_, _, redact_level = self._get_ops_level_from_event_state(
event
)
if user_level < redact_level:
raise AuthError(
403,
"You don't have permission to redact events"
)
def _check_power_levels(self, event):
user_list = event.content.get("users", {})
# Validate users
for k, v in user_list.items():
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
user_level = self._get_power_level_from_event_state(
event,
event.user_id,
)
# Check other levels:
levels_to_check = [
("users_default", []),
("events_default", []),
("ban", []),
("redact", []),
("kick", []),
]
old_list = current_state.content.get("users")
for user in set(old_list.keys() + user_list.keys()):
levels_to_check.append(
(user, ["users"])
)
old_list = current_state.content.get("events")
new_list = event.content.get("events")
for ev_id in set(old_list.keys() + new_list.keys()):
levels_to_check.append(
(ev_id, ["events"])
)
old_state = current_state.content
new_state = event.content
for level_to_check, dir in levels_to_check:
old_loc = old_state
for d in dir:
old_loc = old_loc.get(d, {})
new_loc = new_state
for d in dir:
new_loc = new_loc.get(d, {})
if level_to_check in old_loc:
old_level = int(old_loc[level_to_check])
else:
old_level = None
if level_to_check in new_loc:
new_level = int(new_loc[level_to_check])
else:
new_level = None
if new_level is not None and old_level is not None:
if new_level == old_level:
continue
if old_level > user_level or new_level > user_level:
raise AuthError(
403,
"You don't have permission to add ops level greater "
"than your own"
)