diff options
Diffstat (limited to 'synapse/api')
| -rw-r--r-- | synapse/api/auth.py | 135 |
1 files changed, 124 insertions, 11 deletions
diff --git a/synapse/api/auth.py b/synapse/api/auth.py index 65ee1452ce..df788230fa 100644 --- a/synapse/api/auth.py +++ b/synapse/api/auth.py @@ -20,9 +20,10 @@ from twisted.internet import defer from synapse.api.constants import EventTypes, Membership, JoinRules from synapse.api.errors import AuthError, Codes, SynapseError from synapse.util.logutils import log_function -from synapse.types import UserID +from synapse.types import UserID, EventID import logging +import pymacaroons logger = logging.getLogger(__name__) @@ -40,6 +41,12 @@ 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 = ", + "type = ", + "time < ", + "user_id = ", + ]) def check(self, event, auth_events): """ Checks if this event is correctly authed. @@ -65,6 +72,14 @@ 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,) + ) + # FIXME: Temp hack if event.type == EventTypes.Aliases: return True @@ -91,7 +106,7 @@ 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: @@ -359,7 +374,7 @@ class Auth(object): except KeyError: pass # normal users won't have the user_id query parameter set. - user_info = yield self.get_user_by_access_token(access_token) + user_info = yield self._get_user_by_access_token(access_token) user = user_info["user"] token_id = user_info["token_id"] @@ -386,7 +401,7 @@ class Auth(object): ) @defer.inlineCallbacks - def get_user_by_access_token(self, token): + def _get_user_by_access_token(self, token): """ Get a registered user's ID. Args: @@ -396,6 +411,86 @@ class Auth(object): Raises: AuthError if no user by that token exists or the token is invalid. """ + 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) + + user_prefix = "user_id = " + for caveat in macaroon.caveats: + if caveat.caveat_id.startswith(user_prefix): + user = UserID.from_string(caveat.caveat_id[len(user_prefix):]) + # 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) + raise AuthError( + self.TOKEN_NOT_FOUND_HTTP_STATUS, "No user caveat in macaroon", + errcode=Codes.UNKNOWN_TOKEN + ) + 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): + v = pymacaroons.Verifier() + v.satisfy_exact("gen = 1") + v.satisfy_exact("type = access") + v.satisfy_general(lambda c: c.startswith("user_id = ")) + v.satisfy_general(self._verify_expiry) + 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 + # TODO(daniel): Enable expiry check when clients actually know how to + # refresh tokens. (And remember to enable the tests) + return True + 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( @@ -406,7 +501,6 @@ class Auth(object): "user": UserID.from_string(ret.get("name")), "token_id": ret.get("token_id", None), } - defer.returnValue(user_info) @defer.inlineCallbacks @@ -541,16 +635,35 @@ 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", {}) |