forked-synapse/synapse/api/auth.py
2017-01-05 13:50:22 +00:00

1246 lines
46 KiB
Python

# -*- coding: utf-8 -*-
# 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 pymacaroons
from canonicaljson import encode_canonical_json
from signedjson.key import decode_verify_key_bytes
from signedjson.sign import verify_signed_json, SignatureVerifyException
from twisted.internet import defer
from unpaddedbase64 import decode_base64
import synapse.types
from synapse.api.constants import EventTypes, Membership, JoinRules
from synapse.api.errors import AuthError, Codes, SynapseError, EventSizeError
from synapse.types import UserID, get_domain_from_id
from synapse.util.logcontext import preserve_context_over_fn
from synapse.util.logutils import log_function
from synapse.util.metrics import Measure
logger = logging.getLogger(__name__)
AuthEventTypes = (
EventTypes.Create, EventTypes.Member, EventTypes.PowerLevels,
EventTypes.JoinRules, EventTypes.RoomHistoryVisibility,
EventTypes.ThirdPartyInvite,
)
# guests always get this device id.
GUEST_DEVICE_ID = "guest_device"
class Auth(object):
"""
FIXME: This class contains a mix of functions for authenticating users
of our client-server API and authenticating events added to room graphs.
"""
def __init__(self, hs):
self.hs = hs
self.clock = hs.get_clock()
self.store = hs.get_datastore()
self.state = hs.get_state_handler()
self.TOKEN_NOT_FOUND_HTTP_STATUS = 401
@defer.inlineCallbacks
def check_from_context(self, event, context, do_sig_check=True):
auth_events_ids = yield self.compute_auth_events(
event, context.prev_state_ids, for_verification=True,
)
auth_events = yield self.store.get_events(auth_events_ids)
auth_events = {
(e.type, e.state_key): e for e in auth_events.values()
}
self.check(event, auth_events=auth_events, do_sig_check=do_sig_check)
def check(self, event, auth_events, do_sig_check=True):
""" Checks if this event is correctly authed.
Args:
event: the event being checked.
auth_events (dict: event-key -> event): the existing room state.
Returns:
True if the auth checks pass.
"""
with Measure(self.clock, "auth.check"):
self.check_size_limits(event)
if not hasattr(event, "room_id"):
raise AuthError(500, "Event has no room_id: %s" % event)
if do_sig_check:
sender_domain = get_domain_from_id(event.sender)
event_id_domain = get_domain_from_id(event.event_id)
is_invite_via_3pid = (
event.type == EventTypes.Member
and event.membership == Membership.INVITE
and "third_party_invite" in event.content
)
# Check the sender's domain has signed the event
if not event.signatures.get(sender_domain):
# We allow invites via 3pid to have a sender from a different
# HS, as the sender must match the sender of the original
# 3pid invite. This is checked further down with the
# other dedicated membership checks.
if not is_invite_via_3pid:
raise AuthError(403, "Event not signed by sender's server")
# Check the event_id's domain has signed the event
if not event.signatures.get(event_id_domain):
raise AuthError(403, "Event not signed by sending server")
if auth_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 event.type == EventTypes.Create:
room_id_domain = get_domain_from_id(event.room_id)
if room_id_domain != sender_domain:
raise AuthError(
403,
"Creation event's room_id domain does not match sender's"
)
# FIXME
return True
creation_event = auth_events.get((EventTypes.Create, ""), None)
if not creation_event:
raise SynapseError(
403,
"Room %r does not exist" % (event.room_id,)
)
creating_domain = get_domain_from_id(event.room_id)
originating_domain = get_domain_from_id(event.sender)
if creating_domain != originating_domain:
if not self.can_federate(event, auth_events):
raise AuthError(
403,
"This room has been marked as unfederatable."
)
# FIXME: Temp hack
if event.type == EventTypes.Aliases:
if not event.is_state():
raise AuthError(
403,
"Alias event must be a state event",
)
if not event.state_key:
raise AuthError(
403,
"Alias event must have non-empty state_key"
)
sender_domain = get_domain_from_id(event.sender)
if event.state_key != sender_domain:
raise AuthError(
403,
"Alias event's state_key does not match sender's domain"
)
return True
logger.debug(
"Auth events: %s",
[a.event_id for a in auth_events.values()]
)
if event.type == EventTypes.Member:
allowed = self.is_membership_change_allowed(
event, auth_events
)
if allowed:
logger.debug("Allowing! %s", event)
else:
logger.debug("Denying! %s", event)
return allowed
self.check_event_sender_in_room(event, auth_events)
# Special case to allow m.room.third_party_invite events wherever
# a user is allowed to issue invites. Fixes
# https://github.com/vector-im/vector-web/issues/1208 hopefully
if event.type == EventTypes.ThirdPartyInvite:
user_level = self._get_user_power_level(event.user_id, auth_events)
invite_level = self._get_named_level(auth_events, "invite", 0)
if user_level < invite_level:
raise AuthError(
403, (
"You cannot issue a third party invite for %s." %
(event.content.display_name,)
)
)
else:
return True
self._can_send_event(event, auth_events)
if event.type == EventTypes.PowerLevels:
self._check_power_levels(event, auth_events)
if event.type == EventTypes.Redaction:
self.check_redaction(event, auth_events)
logger.debug("Allowing! %s", event)
def check_size_limits(self, event):
def too_big(field):
raise EventSizeError("%s too large" % (field,))
if len(event.user_id) > 255:
too_big("user_id")
if len(event.room_id) > 255:
too_big("room_id")
if event.is_state() and len(event.state_key) > 255:
too_big("state_key")
if len(event.type) > 255:
too_big("type")
if len(event.event_id) > 255:
too_big("event_id")
if len(encode_canonical_json(event.get_pdu_json())) > 65536:
too_big("event")
@defer.inlineCallbacks
def check_joined_room(self, room_id, user_id, current_state=None):
"""Check if the user is currently joined in the room
Args:
room_id(str): The room to check.
user_id(str): The user to check.
current_state(dict): Optional map of the current state of the room.
If provided then that map is used to check whether they are a
member of the room. Otherwise the current membership is
loaded from the database.
Raises:
AuthError if the user is not in the room.
Returns:
A deferred membership event for the user if the user is in
the room.
"""
if current_state:
member = current_state.get(
(EventTypes.Member, user_id),
None
)
else:
member = yield self.state.get_current_state(
room_id=room_id,
event_type=EventTypes.Member,
state_key=user_id
)
self._check_joined_room(member, user_id, room_id)
defer.returnValue(member)
@defer.inlineCallbacks
def check_user_was_in_room(self, room_id, user_id):
"""Check if the user was in the room at some point.
Args:
room_id(str): The room to check.
user_id(str): The user to check.
Raises:
AuthError if the user was never in the room.
Returns:
A deferred membership event for the user if the user was in the
room. This will be the join event if they are currently joined to
the room. This will be the leave event if they have left the room.
"""
member = yield self.state.get_current_state(
room_id=room_id,
event_type=EventTypes.Member,
state_key=user_id
)
membership = member.membership if member else None
if membership not in (Membership.JOIN, Membership.LEAVE):
raise AuthError(403, "User %s not in room %s" % (
user_id, room_id
))
if membership == Membership.LEAVE:
forgot = yield self.store.did_forget(user_id, room_id)
if forgot:
raise AuthError(403, "User %s not in room %s" % (
user_id, room_id
))
defer.returnValue(member)
@defer.inlineCallbacks
def check_host_in_room(self, room_id, host):
with Measure(self.clock, "check_host_in_room"):
latest_event_ids = yield self.store.get_latest_event_ids_in_room(room_id)
logger.info("calling resolve_state_groups from check_host_in_room")
entry = yield self.state.resolve_state_groups(
room_id, latest_event_ids
)
ret = yield self.store.is_host_joined(
room_id, host, entry.state_group, entry.state
)
defer.returnValue(ret)
def check_event_sender_in_room(self, event, auth_events):
key = (EventTypes.Member, event.user_id, )
member_event = auth_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)
))
def can_federate(self, event, auth_events):
creation_event = auth_events.get((EventTypes.Create, ""))
return creation_event.content.get("m.federate", True) is True
@log_function
def is_membership_change_allowed(self, event, auth_events):
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 = (EventTypes.Create, "", )
create = auth_events.get(key)
if create and event.prev_events[0][0] == create.event_id:
if create.content["creator"] == event.state_key:
return True
target_user_id = event.state_key
creating_domain = get_domain_from_id(event.room_id)
target_domain = get_domain_from_id(target_user_id)
if creating_domain != target_domain:
if not self.can_federate(event, auth_events):
raise AuthError(
403,
"This room has been marked as unfederatable."
)
# get info about the caller
key = (EventTypes.Member, event.user_id, )
caller = auth_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 = (EventTypes.Member, target_user_id, )
target = auth_events.get(key)
target_in_room = target and target.membership == Membership.JOIN
target_banned = target and target.membership == Membership.BAN
key = (EventTypes.JoinRules, "", )
join_rule_event = auth_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_user_power_level(event.user_id, auth_events)
target_level = self._get_user_power_level(
target_user_id, auth_events
)
# FIXME (erikj): What should we do here as the default?
ban_level = self._get_named_level(auth_events, "ban", 50)
logger.debug(
"is_membership_change_allowed: %s",
{
"caller_in_room": caller_in_room,
"caller_invited": caller_invited,
"target_banned": target_banned,
"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 and "third_party_invite" in event.content:
if not self._verify_third_party_invite(event, auth_events):
raise AuthError(403, "You are not invited to this room.")
if target_banned:
raise AuthError(
403, "%s is banned from the room" % (target_user_id,)
)
return True
if Membership.JOIN != membership:
if (caller_invited
and Membership.LEAVE == membership
and target_user_id == event.user_id):
return True
if not caller_in_room: # caller isn't joined
raise AuthError(
403,
"%s not in room %s." % (event.user_id, event.room_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 target_banned:
raise AuthError(
403, "%s is banned from the room" % (target_user_id,)
)
elif target_in_room: # the target is already in the room.
raise AuthError(403, "%s is already in the room." %
target_user_id)
else:
invite_level = self._get_named_level(auth_events, "invite", 0)
if user_level < invite_level:
raise AuthError(
403, "You cannot invite user %s." % 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 target_banned:
raise AuthError(403, "You are banned from this room")
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 target_banned and user_level < ban_level:
raise AuthError(
403, "You cannot unban user &s." % (target_user_id,)
)
elif target_user_id != event.user_id:
kick_level = self._get_named_level(auth_events, "kick", 50)
if user_level < kick_level or user_level <= target_level:
raise AuthError(
403, "You cannot kick user %s." % target_user_id
)
elif Membership.BAN == membership:
if user_level < ban_level or user_level <= target_level:
raise AuthError(403, "You don't have permission to ban")
else:
raise AuthError(500, "Unknown membership %s" % membership)
return True
def _verify_third_party_invite(self, event, auth_events):
"""
Validates that the invite event is authorized by a previous third-party invite.
Checks that the public key, and keyserver, match those in the third party invite,
and that the invite event has a signature issued using that public key.
Args:
event: The m.room.member join event being validated.
auth_events: All relevant previous context events which may be used
for authorization decisions.
Return:
True if the event fulfills the expectations of a previous third party
invite event.
"""
if "third_party_invite" not in event.content:
return False
if "signed" not in event.content["third_party_invite"]:
return False
signed = event.content["third_party_invite"]["signed"]
for key in {"mxid", "token"}:
if key not in signed:
return False
token = signed["token"]
invite_event = auth_events.get(
(EventTypes.ThirdPartyInvite, token,)
)
if not invite_event:
return False
if invite_event.sender != event.sender:
return False
if event.user_id != invite_event.user_id:
return False
if signed["mxid"] != event.state_key:
return False
if signed["token"] != token:
return False
for public_key_object in self.get_public_keys(invite_event):
public_key = public_key_object["public_key"]
try:
for server, signature_block in signed["signatures"].items():
for key_name, encoded_signature in signature_block.items():
if not key_name.startswith("ed25519:"):
continue
verify_key = decode_verify_key_bytes(
key_name,
decode_base64(public_key)
)
verify_signed_json(signed, server, verify_key)
# We got the public key from the invite, so we know that the
# correct server signed the signed bundle.
# The caller is responsible for checking that the signing
# server has not revoked that public key.
return True
except (KeyError, SignatureVerifyException,):
continue
return False
def get_public_keys(self, invite_event):
public_keys = []
if "public_key" in invite_event.content:
o = {
"public_key": invite_event.content["public_key"],
}
if "key_validity_url" in invite_event.content:
o["key_validity_url"] = invite_event.content["key_validity_url"]
public_keys.append(o)
public_keys.extend(invite_event.content.get("public_keys", []))
return public_keys
def _get_power_level_event(self, auth_events):
key = (EventTypes.PowerLevels, "", )
return auth_events.get(key)
def _get_user_power_level(self, user_id, auth_events):
power_level_event = self._get_power_level_event(auth_events)
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)
if level is None:
return 0
else:
return int(level)
else:
key = (EventTypes.Create, "", )
create_event = auth_events.get(key)
if (create_event is not None and
create_event.content["creator"] == user_id):
return 100
else:
return 0
def _get_named_level(self, auth_events, name, default):
power_level_event = self._get_power_level_event(auth_events)
if not power_level_event:
return default
level = power_level_event.content.get(name, None)
if level is not None:
return int(level)
else:
return default
@defer.inlineCallbacks
def get_user_by_req(self, request, allow_guest=False, rights="access"):
""" Get a registered user's ID.
Args:
request - An HTTP request with an access_token query parameter.
Returns:
defer.Deferred: resolves to a ``synapse.types.Requester`` object
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:
user_id, app_service = yield self._get_appservice_user_id(request)
if user_id:
request.authenticated_entity = user_id
defer.returnValue(
synapse.types.create_requester(user_id, app_service=app_service)
)
access_token = get_access_token_from_request(
request, self.TOKEN_NOT_FOUND_HTTP_STATUS
)
user_info = yield self.get_user_by_access_token(access_token, rights)
user = user_info["user"]
token_id = user_info["token_id"]
is_guest = user_info["is_guest"]
# device_id may not be present if get_user_by_access_token has been
# stubbed out.
device_id = user_info.get("device_id")
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:
preserve_context_over_fn(
self.store.insert_client_ip,
user=user,
access_token=access_token,
ip=ip_addr,
user_agent=user_agent,
device_id=device_id,
)
if is_guest and not allow_guest:
raise AuthError(
403, "Guest access not allowed", errcode=Codes.GUEST_ACCESS_FORBIDDEN
)
request.authenticated_entity = user.to_string()
defer.returnValue(synapse.types.create_requester(
user, token_id, is_guest, device_id, app_service=app_service)
)
except KeyError:
raise AuthError(
self.TOKEN_NOT_FOUND_HTTP_STATUS, "Missing access token.",
errcode=Codes.MISSING_TOKEN
)
@defer.inlineCallbacks
def _get_appservice_user_id(self, request):
app_service = self.store.get_app_service_by_token(
get_access_token_from_request(
request, self.TOKEN_NOT_FOUND_HTTP_STATUS
)
)
if app_service is None:
defer.returnValue((None, None))
if "user_id" not in request.args:
defer.returnValue((app_service.sender, app_service))
user_id = request.args["user_id"][0]
if app_service.sender == user_id:
defer.returnValue((app_service.sender, app_service))
if not app_service.is_interested_in_user(user_id):
raise AuthError(
403,
"Application service cannot masquerade as this user."
)
if not (yield self.store.get_user_by_id(user_id)):
raise AuthError(
403,
"Application service has not registered this user"
)
defer.returnValue((user_id, app_service))
@defer.inlineCallbacks
def get_user_by_access_token(self, token, rights="access"):
""" Validate access token and get user_id from it
Args:
token (str): The access token to get the user by.
rights (str): The operation being performed; the access token must
allow this.
Returns:
dict : dict that includes the user and the ID of their access token.
Raises:
AuthError if no user by that token exists or the token is invalid.
"""
try:
macaroon = pymacaroons.Macaroon.deserialize(token)
except Exception: # deserialize can throw more-or-less anything
# doesn't look like a macaroon: treat it as an opaque token which
# must be in the database.
# TODO: it would be nice to get rid of this, but apparently some
# people use access tokens which aren't macaroons
r = yield self._look_up_user_by_access_token(token)
defer.returnValue(r)
try:
user_id = self.get_user_id_from_macaroon(macaroon)
user = UserID.from_string(user_id)
self.validate_macaroon(
macaroon, rights, self.hs.config.expire_access_token,
user_id=user_id,
)
guest = False
for caveat in macaroon.caveats:
if caveat.caveat_id == "guest = true":
guest = True
if guest:
# Guest access tokens are not stored in the database (there can
# only be one access token per guest, anyway).
#
# In order to prevent guest access tokens being used as regular
# user access tokens (and hence getting around the invalidation
# process), we look up the user id and check that it is indeed
# a guest user.
#
# It would of course be much easier to store guest access
# tokens in the database as well, but that would break existing
# guest tokens.
stored_user = yield self.store.get_user_by_id(user_id)
if not stored_user:
raise AuthError(
self.TOKEN_NOT_FOUND_HTTP_STATUS,
"Unknown user_id %s" % user_id,
errcode=Codes.UNKNOWN_TOKEN
)
if not stored_user["is_guest"]:
raise AuthError(
self.TOKEN_NOT_FOUND_HTTP_STATUS,
"Guest access token used for regular user",
errcode=Codes.UNKNOWN_TOKEN
)
ret = {
"user": user,
"is_guest": True,
"token_id": None,
# all guests get the same device id
"device_id": GUEST_DEVICE_ID,
}
elif rights == "delete_pusher":
# We don't store these tokens in the database
ret = {
"user": user,
"is_guest": False,
"token_id": None,
"device_id": None,
}
else:
# This codepath exists for several reasons:
# * so that we can actually return a token ID, which is used
# in some parts of the schema (where we probably ought to
# use device IDs instead)
# * the only way we currently have to invalidate an
# access_token is by removing it from the database, so we
# have to check here that it is still in the db
# * some attributes (notably device_id) aren't stored in the
# macaroon. They probably should be.
# TODO: build the dictionary from the macaroon once the
# above are fixed
ret = yield self._look_up_user_by_access_token(token)
if ret["user"] != user:
logger.error(
"Macaroon user (%s) != DB user (%s)",
user,
ret["user"]
)
raise AuthError(
self.TOKEN_NOT_FOUND_HTTP_STATUS,
"User mismatch in macaroon",
errcode=Codes.UNKNOWN_TOKEN
)
defer.returnValue(ret)
except (pymacaroons.exceptions.MacaroonException, TypeError, ValueError):
raise AuthError(
self.TOKEN_NOT_FOUND_HTTP_STATUS, "Invalid macaroon passed.",
errcode=Codes.UNKNOWN_TOKEN
)
def get_user_id_from_macaroon(self, macaroon):
"""Retrieve the user_id given by the caveats on the macaroon.
Does *not* validate the macaroon.
Args:
macaroon (pymacaroons.Macaroon): The macaroon to validate
Returns:
(str) user id
Raises:
AuthError if there is no user_id caveat in the macaroon
"""
user_prefix = "user_id = "
for caveat in macaroon.caveats:
if caveat.caveat_id.startswith(user_prefix):
return caveat.caveat_id[len(user_prefix):]
raise AuthError(
self.TOKEN_NOT_FOUND_HTTP_STATUS, "No user caveat in macaroon",
errcode=Codes.UNKNOWN_TOKEN
)
def validate_macaroon(self, macaroon, type_string, verify_expiry, user_id):
"""
validate that a Macaroon is understood by and was signed by this server.
Args:
macaroon(pymacaroons.Macaroon): The macaroon to validate
type_string(str): The kind of token required (e.g. "access",
"delete_pusher")
verify_expiry(bool): Whether to verify whether the macaroon has expired.
user_id (str): The user_id required
"""
v = pymacaroons.Verifier()
# the verifier runs a test for every caveat on the macaroon, to check
# that it is met for the current request. Each caveat must match at
# least one of the predicates specified by satisfy_exact or
# specify_general.
v.satisfy_exact("gen = 1")
v.satisfy_exact("type = " + type_string)
v.satisfy_exact("user_id = %s" % user_id)
v.satisfy_exact("guest = true")
# verify_expiry should really always be True, but there exist access
# tokens in the wild which expire when they should not, so we can't
# enforce expiry yet (so we have to allow any caveat starting with
# 'time < ' in access tokens).
#
# On the other hand, short-term login tokens (as used by CAS login, for
# example) have an expiry time which we do want to enforce.
if verify_expiry:
v.satisfy_general(self._verify_expiry)
else:
v.satisfy_general(lambda c: c.startswith("time < "))
# access_tokens include a nonce for uniqueness: any value is acceptable
v.satisfy_general(lambda c: c.startswith("nonce = "))
v.verify(macaroon, self.hs.config.macaroon_secret_key)
def _verify_expiry(self, caveat):
prefix = "time < "
if not caveat.startswith(prefix):
return False
expiry = int(caveat[len(prefix):])
now = self.hs.get_clock().time_msec()
return now < expiry
@defer.inlineCallbacks
def _look_up_user_by_access_token(self, token):
ret = yield self.store.get_user_by_access_token(token)
if not ret:
logger.warn("Unrecognised access token - not in store: %s" % (token,))
raise AuthError(
self.TOKEN_NOT_FOUND_HTTP_STATUS, "Unrecognised access token.",
errcode=Codes.UNKNOWN_TOKEN
)
# we use ret.get() below because *lots* of unit tests stub out
# get_user_by_access_token in a way where it only returns a couple of
# the fields.
user_info = {
"user": UserID.from_string(ret.get("name")),
"token_id": ret.get("token_id", None),
"is_guest": False,
"device_id": ret.get("device_id"),
}
defer.returnValue(user_info)
def get_appservice_by_req(self, request):
try:
token = get_access_token_from_request(
request, self.TOKEN_NOT_FOUND_HTTP_STATUS
)
service = self.store.get_app_service_by_token(token)
if not service:
logger.warn("Unrecognised appservice access token: %s" % (token,))
raise AuthError(
self.TOKEN_NOT_FOUND_HTTP_STATUS,
"Unrecognised access token.",
errcode=Codes.UNKNOWN_TOKEN
)
request.authenticated_entity = service.sender
return defer.succeed(service)
except KeyError:
raise AuthError(
self.TOKEN_NOT_FOUND_HTTP_STATUS, "Missing access token."
)
def is_server_admin(self, user):
return self.store.is_server_admin(user)
@defer.inlineCallbacks
def add_auth_events(self, builder, context):
auth_ids = yield self.compute_auth_events(builder, context.prev_state_ids)
auth_events_entries = yield self.store.add_event_hashes(
auth_ids
)
builder.auth_events = auth_events_entries
@defer.inlineCallbacks
def compute_auth_events(self, event, current_state_ids, for_verification=False):
if event.type == EventTypes.Create:
defer.returnValue([])
auth_ids = []
key = (EventTypes.PowerLevels, "", )
power_level_event_id = current_state_ids.get(key)
if power_level_event_id:
auth_ids.append(power_level_event_id)
key = (EventTypes.JoinRules, "", )
join_rule_event_id = current_state_ids.get(key)
key = (EventTypes.Member, event.user_id, )
member_event_id = current_state_ids.get(key)
key = (EventTypes.Create, "", )
create_event_id = current_state_ids.get(key)
if create_event_id:
auth_ids.append(create_event_id)
if join_rule_event_id:
join_rule_event = yield self.store.get_event(join_rule_event_id)
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 == EventTypes.Member:
e_type = event.content["membership"]
if e_type in [Membership.JOIN, Membership.INVITE]:
if join_rule_event_id:
auth_ids.append(join_rule_event_id)
if e_type == Membership.JOIN:
if member_event_id and not is_public:
auth_ids.append(member_event_id)
else:
if member_event_id:
auth_ids.append(member_event_id)
if for_verification:
key = (EventTypes.Member, event.state_key, )
existing_event_id = current_state_ids.get(key)
if existing_event_id:
auth_ids.append(existing_event_id)
if e_type == Membership.INVITE:
if "third_party_invite" in event.content:
key = (
EventTypes.ThirdPartyInvite,
event.content["third_party_invite"]["signed"]["token"]
)
third_party_invite_id = current_state_ids.get(key)
if third_party_invite_id:
auth_ids.append(third_party_invite_id)
elif member_event_id:
member_event = yield self.store.get_event(member_event_id)
if member_event.content["membership"] == Membership.JOIN:
auth_ids.append(member_event.event_id)
defer.returnValue(auth_ids)
def _get_send_level(self, etype, state_key, auth_events):
key = (EventTypes.PowerLevels, "", )
send_level_event = auth_events.get(key)
send_level = None
if send_level_event:
send_level = send_level_event.content.get("events", {}).get(
etype
)
if send_level is None:
if state_key is not None:
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
return send_level
@log_function
def _can_send_event(self, event, auth_events):
send_level = self._get_send_level(
event.type, event.get("state_key", None), auth_events
)
user_level = self._get_user_power_level(event.user_id, auth_events)
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 event.state_key.startswith("@"):
if event.state_key != event.user_id:
raise AuthError(
403,
"You are not allowed to set others state"
)
return True
def check_redaction(self, event, auth_events):
"""Check whether the event sender is allowed to redact the target event.
Returns:
True if the the sender is allowed to redact the target event if the
target event was created by them.
False if the sender is allowed to redact the target event with no
further checks.
Raises:
AuthError if the event sender is definitely not allowed to redact
the target event.
"""
user_level = self._get_user_power_level(event.user_id, auth_events)
redact_level = self._get_named_level(auth_events, "redact", 50)
if user_level >= redact_level:
return False
redacter_domain = get_domain_from_id(event.event_id)
redactee_domain = get_domain_from_id(event.redacts)
if redacter_domain == redactee_domain:
return True
raise AuthError(
403,
"You don't have permission to redact events"
)
def _check_power_levels(self, event, auth_events):
user_list = event.content.get("users", {})
# Validate users
for k, v in user_list.items():
try:
UserID.from_string(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 = auth_events.get(key)
if not current_state:
return
user_level = self._get_user_power_level(event.user_id, auth_events)
# Check other levels:
levels_to_check = [
("users_default", None),
("events_default", None),
("state_default", None),
("ban", None),
("redact", None),
("kick", None),
("invite", None),
]
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
new_loc = new_state
if dir:
old_loc = old_loc.get(dir, {})
new_loc = new_loc.get(dir, {})
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 dir == "users" and level_to_check != event.user_id:
if old_level == user_level:
raise AuthError(
403,
"You don't have permission to remove ops level equal "
"to your own"
)
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"
)
@defer.inlineCallbacks
def check_can_change_room_list(self, room_id, user):
"""Check if the user is allowed to edit the room's entry in the
published room list.
Args:
room_id (str)
user (UserID)
"""
is_admin = yield self.is_server_admin(user)
if is_admin:
defer.returnValue(True)
user_id = user.to_string()
yield self.check_joined_room(room_id, user_id)
# We currently require the user is a "moderator" in the room. We do this
# by checking if they would (theoretically) be able to change the
# m.room.aliases events
power_level_event = yield self.state.get_current_state(
room_id, EventTypes.PowerLevels, ""
)
auth_events = {}
if power_level_event:
auth_events[(EventTypes.PowerLevels, "")] = power_level_event
send_level = self._get_send_level(
EventTypes.Aliases, "", auth_events
)
user_level = self._get_user_power_level(user_id, auth_events)
if user_level < send_level:
raise AuthError(
403,
"This server requires you to be a moderator in the room to"
" edit its room list entry"
)
def has_access_token(request):
"""Checks if the request has an access_token.
Returns:
bool: False if no access_token was given, True otherwise.
"""
query_params = request.args.get("access_token")
auth_headers = request.requestHeaders.getRawHeaders("Authorization")
return bool(query_params) or bool(auth_headers)
def get_access_token_from_request(request, token_not_found_http_status=401):
"""Extracts the access_token from the request.
Args:
request: The http request.
token_not_found_http_status(int): The HTTP status code to set in the
AuthError if the token isn't found. This is used in some of the
legacy APIs to change the status code to 403 from the default of
401 since some of the old clients depended on auth errors returning
403.
Returns:
str: The access_token
Raises:
AuthError: If there isn't an access_token in the request.
"""
auth_headers = request.requestHeaders.getRawHeaders("Authorization")
query_params = request.args.get("access_token")
if auth_headers:
# Try the get the access_token from a "Authorization: Bearer"
# header
if query_params is not None:
raise AuthError(
token_not_found_http_status,
"Mixing Authorization headers and access_token query parameters.",
errcode=Codes.MISSING_TOKEN,
)
if len(auth_headers) > 1:
raise AuthError(
token_not_found_http_status,
"Too many Authorization headers.",
errcode=Codes.MISSING_TOKEN,
)
parts = auth_headers[0].split(" ")
if parts[0] == "Bearer" and len(parts) == 2:
return parts[1]
else:
raise AuthError(
token_not_found_http_status,
"Invalid Authorization header.",
errcode=Codes.MISSING_TOKEN,
)
else:
# Try to get the access_token from the query params.
if not query_params:
raise AuthError(
token_not_found_http_status,
"Missing access token.",
errcode=Codes.MISSING_TOKEN
)
return query_params[0]