diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 1e3b0fbfb7..8111b34428 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -14,15 +14,20 @@
# limitations under the License.
"""This module contains classes for authenticating the user."""
+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 synapse.api.constants import EventTypes, Membership, JoinRules
-from synapse.api.errors import AuthError, Codes, SynapseError
+from synapse.api.errors import AuthError, Codes, SynapseError, EventSizeError
+from synapse.types import RoomID, UserID, EventID
from synapse.util.logutils import log_function
-from synapse.types import UserID, ClientInfo
+from unpaddedbase64 import decode_base64
import logging
+import pymacaroons
logger = logging.getLogger(__name__)
@@ -30,6 +35,7 @@ logger = logging.getLogger(__name__)
AuthEventTypes = (
EventTypes.Create, EventTypes.Member, EventTypes.PowerLevels,
EventTypes.JoinRules, EventTypes.RoomHistoryVisibility,
+ EventTypes.ThirdPartyInvite,
)
@@ -40,6 +46,13 @@ class Auth(object):
self.store = hs.get_datastore()
self.state = hs.get_state_handler()
self.TOKEN_NOT_FOUND_HTTP_STATUS = 401
+ self._KNOWN_CAVEAT_PREFIXES = set([
+ "gen = ",
+ "guest = ",
+ "type = ",
+ "time < ",
+ "user_id = ",
+ ])
def check(self, event, auth_events):
""" Checks if this event is correctly authed.
@@ -52,6 +65,8 @@ class Auth(object):
Returns:
True if the auth checks pass.
"""
+ self.check_size_limits(event)
+
try:
if not hasattr(event, "room_id"):
raise AuthError(500, "Event has no room_id: %s" % event)
@@ -65,6 +80,23 @@ class Auth(object):
# 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 = RoomID.from_string(event.room_id).domain
+ originating_domain = UserID.from_string(event.sender).domain
+ 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:
return True
@@ -91,7 +123,7 @@ class Auth(object):
self._check_power_levels(event, auth_events)
if event.type == EventTypes.Redaction:
- self._check_redaction(event, auth_events)
+ self.check_redaction(event, auth_events)
logger.debug("Allowing! %s", event)
except AuthError as e:
@@ -102,8 +134,39 @@ class Auth(object):
logger.info("Denying! %s", event)
raise
+ 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),
@@ -120,6 +183,33 @@ class Auth(object):
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
+ ))
+
+ defer.returnValue(member)
+
+ @defer.inlineCallbacks
def check_host_in_room(self, room_id, host):
curr_state = yield self.state.get_current_state(room_id)
@@ -153,6 +243,11 @@ class Auth(object):
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"]
@@ -168,6 +263,15 @@ class Auth(object):
target_user_id = event.state_key
+ creating_domain = RoomID.from_string(event.room_id).domain
+ target_domain = UserID.from_string(target_user_id).domain
+ 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)
@@ -213,8 +317,17 @@ class Auth(object):
}
)
+ 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.")
+ return True
+
if Membership.JOIN != membership:
- # JOIN is the only action you can perform if you're not in the room
+ 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,
@@ -278,6 +391,66 @@ class Auth(object):
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 event.user_id != invite_event.user_id:
+ return False
+ try:
+ public_key = invite_event.content["public_key"]
+ if signed["mxid"] != event.state_key:
+ return False
+ if signed["token"] != token:
+ return False
+ for server, signature_block in signed["signatures"].items():
+ for key_name, encoded_signature in signature_block.items():
+ if not key_name.startswith("ed25519:"):
+ return False
+ 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
+ return False
+ except (KeyError, SignatureVerifyException,):
+ return False
+
def _get_power_level_event(self, auth_events):
key = (EventTypes.PowerLevels, "", )
return auth_events.get(key)
@@ -316,15 +489,15 @@ class Auth(object):
return default
@defer.inlineCallbacks
- def get_user_by_req(self, request):
+ def get_user_by_req(self, request, allow_guest=False):
""" Get a registered user's ID.
Args:
request - An HTTP request with an access_token query parameter.
Returns:
- tuple : of UserID and device string:
- User ID object of the user making the request
- ClientInfo object of the client instance the user is using
+ tuple of:
+ UserID (str)
+ Access token ID (str)
Raises:
AuthError if no user by that token exists or the token is invalid.
"""
@@ -354,17 +527,15 @@ class Auth(object):
request.authenticated_entity = user_id
- defer.returnValue(
- (UserID.from_string(user_id), ClientInfo("", ""))
- )
+ defer.returnValue((UserID.from_string(user_id), "", False))
return
except KeyError:
pass # normal users won't have the user_id query parameter set.
- user_info = yield self.get_user_by_token(access_token)
+ user_info = yield self._get_user_by_access_token(access_token)
user = user_info["user"]
- device_id = user_info["device_id"]
token_id = user_info["token_id"]
+ is_guest = user_info["is_guest"]
ip_addr = self.hs.get_ip_from_request(request)
user_agent = request.requestHeaders.getRawHeaders(
@@ -375,14 +546,18 @@ class Auth(object):
self.store.insert_client_ip(
user=user,
access_token=access_token,
- device_id=user_info["device_id"],
ip=ip_addr,
user_agent=user_agent
)
+ 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((user, ClientInfo(device_id, token_id)))
+ defer.returnValue((user, token_id, is_guest,))
except KeyError:
raise AuthError(
self.TOKEN_NOT_FOUND_HTTP_STATUS, "Missing access token.",
@@ -390,30 +565,124 @@ class Auth(object):
)
@defer.inlineCallbacks
- def get_user_by_token(self, token):
+ def _get_user_by_access_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.
+ 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.
"""
- ret = yield self.store.get_user_by_token(token)
+ try:
+ ret = yield self._get_user_from_macaroon(token)
+ except AuthError:
+ # TODO(daniel): Remove this fallback when all existing access tokens
+ # have been re-issued as macaroons.
+ ret = yield self._look_up_user_by_access_token(token)
+ defer.returnValue(ret)
+
+ @defer.inlineCallbacks
+ def _get_user_from_macaroon(self, macaroon_str):
+ try:
+ macaroon = pymacaroons.Macaroon.deserialize(macaroon_str)
+ self.validate_macaroon(
+ macaroon, "access",
+ [lambda c: c.startswith("time < ")]
+ )
+
+ user_prefix = "user_id = "
+ user = None
+ guest = False
+ for caveat in macaroon.caveats:
+ if caveat.caveat_id.startswith(user_prefix):
+ user = UserID.from_string(caveat.caveat_id[len(user_prefix):])
+ elif caveat.caveat_id == "guest = true":
+ guest = True
+
+ if user is None:
+ raise AuthError(
+ self.TOKEN_NOT_FOUND_HTTP_STATUS, "No user caveat in macaroon",
+ errcode=Codes.UNKNOWN_TOKEN
+ )
+
+ if guest:
+ ret = {
+ "user": user,
+ "is_guest": True,
+ "token_id": None,
+ }
+ else:
+ # This codepath exists so that we can actually return a
+ # token ID, because we use token IDs in place of device
+ # identifiers throughout the codebase.
+ # TODO(daniel): Remove this fallback when device IDs are
+ # properly implemented.
+ ret = yield self._look_up_user_by_access_token(macaroon_str)
+ 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 validate_macaroon(self, macaroon, type_string, additional_validation_functions):
+ v = pymacaroons.Verifier()
+ v.satisfy_exact("gen = 1")
+ v.satisfy_exact("type = " + type_string)
+ v.satisfy_general(lambda c: c.startswith("user_id = "))
+ v.satisfy_exact("guest = true")
+
+ for validation_function in additional_validation_functions:
+ v.satisfy_general(validation_function)
+ v.verify(macaroon, self.hs.config.macaroon_secret_key)
+
+ v = pymacaroons.Verifier()
+ v.satisfy_general(self._verify_recognizes_caveats)
+ 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
+
+ def _verify_recognizes_caveats(self, caveat):
+ first_space = caveat.find(" ")
+ if first_space < 0:
+ return False
+ second_space = caveat.find(" ", first_space + 1)
+ if second_space < 0:
+ return False
+ return caveat[:second_space + 1] in self._KNOWN_CAVEAT_PREFIXES
+
+ @defer.inlineCallbacks
+ def _look_up_user_by_access_token(self, token):
+ ret = yield self.store.get_user_by_access_token(token)
if not ret:
raise AuthError(
self.TOKEN_NOT_FOUND_HTTP_STATUS, "Unrecognised access token.",
errcode=Codes.UNKNOWN_TOKEN
)
user_info = {
- "admin": bool(ret.get("admin", False)),
- "device_id": ret.get("device_id"),
"user": UserID.from_string(ret.get("name")),
"token_id": ret.get("token_id", None),
+ "is_guest": False,
}
-
defer.returnValue(user_info)
@defer.inlineCallbacks
@@ -488,6 +757,16 @@ class Auth(object):
else:
if member_event:
auth_ids.append(member_event.event_id)
+
+ if e_type == Membership.INVITE:
+ if "third_party_invite" in event.content:
+ key = (
+ EventTypes.ThirdPartyInvite,
+ event.content["third_party_invite"]["token"]
+ )
+ third_party_invite = current_state.get(key)
+ if third_party_invite:
+ auth_ids.append(third_party_invite.event_id)
elif member_event:
if member_event.content["membership"] == Membership.JOIN:
auth_ids.append(member_event.event_id)
@@ -548,16 +827,35 @@ class Auth(object):
return True
- def _check_redaction(self, event, auth_events):
+ 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:
- raise AuthError(
- 403,
- "You don't have permission to redact events"
- )
+ if user_level > redact_level:
+ return False
+
+ redacter_domain = EventID.from_string(event.event_id).domain
+ redactee_domain = EventID.from_string(event.redacts).domain
+ 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", {})
|
