synapse-product/synapse/api/auth.py

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# -*- coding: utf-8 -*-
# Copyright 2014 OpenMarket Ltd
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#
# 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.
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"""This module contains classes for authenticating the user."""
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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
from synapse.util.logutils import log_function
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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):
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""" 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"):
is_state = hasattr(event, "state_key")
if event.type == RoomMemberEvent.TYPE:
yield self._can_replace_state(event)
allowed = yield self.is_membership_change_allowed(event)
defer.returnValue(allowed)
return
self._check_joined_room(
member=snapshot.membership_state,
user_id=snapshot.user_id,
room_id=snapshot.room_id,
)
if is_state:
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# TODO (erikj): This really only should be called for *new*
# state
yield self._can_add_state(event)
yield self._can_replace_state(event)
else:
yield self._can_send_event(event)
if event.type == RoomPowerLevelsEvent.TYPE:
yield self._check_power_levels(event)
defer.returnValue(True)
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else:
raise AuthError(500, "Unknown event: %s" % event)
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except AuthError as e:
logger.info("Event auth check failed on event %s with msg: %s",
event, e.msg)
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)
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defer.returnValue(member)
except AttributeError:
pass
defer.returnValue(None)
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)
))
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@defer.inlineCallbacks
def is_membership_change_allowed(self, event):
target_user_id = event.state_key
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# does this room even exist
room = yield self.store.get_room(event.room_id)
if not room:
raise AuthError(403, "Room does not exist")
# get info about the caller
try:
caller = yield self.store.get_room_member(
user_id=event.user_id,
room_id=event.room_id)
except:
caller = None
caller_in_room = caller and caller.membership == "join"
# get info about the target
try:
target = yield self.store.get_room_member(
user_id=target_user_id,
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room_id=event.room_id)
except:
target = None
target_in_room = target and target.membership == "join"
membership = event.content["membership"]
join_rule = yield self.store.get_room_join_rule(event.room_id)
if not join_rule:
join_rule = JoinRules.INVITE
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if Membership.INVITE == membership:
# TODO (erikj): We should probably handle this more intelligently
# PRIVATE join rules.
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# 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)
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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:
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raise AuthError(403, "Cannot force another user to join.")
elif join_rule == JoinRules.PUBLIC or room.is_public:
pass
elif join_rule == JoinRules.INVITE:
if (
not caller or caller.membership not in
[Membership.INVITE, Membership.JOIN]
):
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")
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elif Membership.LEAVE == membership:
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# TODO (erikj): Implement kicks.
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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:
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user_level = yield self.store.get_power_level(
event.room_id,
event.user_id,
)
_, kick_level = yield self.store.get_ops_levels(event.room_id)
if kick_level:
kick_level = int(kick_level)
else:
kick_level = 50
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if user_level < kick_level:
raise AuthError(
403, "You cannot kick user %s." % target_user_id
)
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elif Membership.BAN == membership:
user_level = yield self.store.get_power_level(
event.room_id,
event.user_id,
)
ban_level, _ = yield self.store.get_ops_levels(event.room_id)
if ban_level:
ban_level = int(ban_level)
else:
ban_level = 50 # FIXME (erikj): What should we do here?
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if user_level < ban_level:
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raise AuthError(403, "You don't have permission to ban")
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else:
raise AuthError(500, "Unknown membership %s" % membership)
defer.returnValue(True)
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:
return self.get_user_by_token(request.args["access_token"][0])
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:
UserID : User ID object of the user who has that access token.
Raises:
AuthError if no user by that token exists or the token is invalid.
"""
try:
user_id = yield self.store.get_user_by_token(token=token)
if not user_id:
raise StoreError()
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defer.returnValue(self.hs.parse_userid(user_id))
except StoreError:
raise AuthError(403, "Unrecognised access token.",
errcode=Codes.UNKNOWN_TOKEN)
@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 = yield self.store.get_power_level(
event.room_id,
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 = yield self.store.get_power_level(
event.room_id,
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)
@defer.inlineCallbacks
def _can_replace_state(self, event):
current_state = yield self.store.get_current_state(
event.room_id,
event.type,
event.state_key,
)
if current_state:
current_state = current_state[0]
user_level = yield self.store.get_power_level(
event.room_id,
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
)
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"
)
@defer.inlineCallbacks
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,))
current_state = yield self.store.get_current_state(
event.room_id,
event.type,
event.state_key,
)
if not current_state:
return
else:
current_state = current_state[0]
user_level = yield self.store.get_power_level(
event.room_id,
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(old_people.keys()) - set(new_people.keys())
same = set(old_people.keys()) & set(new_people.keys())
for r in removed:
if int(old_list.content[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"
)