diff options
| -rw-r--r-- | changelog.d/6335.bugfix | 1 | ||||
| -rw-r--r-- | synapse/handlers/auth.py | 84 | ||||
| -rw-r--r-- | synapse/rest/client/v1/login.py | 111 |
3 files changed, 126 insertions, 70 deletions
diff --git a/changelog.d/6335.bugfix b/changelog.d/6335.bugfix new file mode 100644 index 0000000000..a95f6b9eec --- /dev/null +++ b/changelog.d/6335.bugfix @@ -0,0 +1 @@ +Fix bug where `rc_login` ratelimiting would prematurely kick in. diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py index c9d0db4823..54a71c49d2 100644 --- a/synapse/handlers/auth.py +++ b/synapse/handlers/auth.py @@ -102,8 +102,9 @@ class AuthHandler(BaseHandler): login_types.append(t) self._supported_login_types = login_types - self._account_ratelimiter = Ratelimiter() - self._failed_attempts_ratelimiter = Ratelimiter() + # Ratelimiter for failed auth during UIA. Uses same ratelimit config + # as per `rc_login.failed_attempts`. + self._failed_uia_attempts_ratelimiter = Ratelimiter() self._clock = self.hs.get_clock() @@ -133,12 +134,38 @@ class AuthHandler(BaseHandler): AuthError if the client has completed a login flow, and it gives a different user to `requester` + + LimitExceededError if the ratelimiter's failed request count for this + user is too high to proceed + """ + user_id = requester.user.to_string() + + # Check if we should be ratelimited due to too many previous failed attempts + self._failed_uia_attempts_ratelimiter.ratelimit( + user_id, + time_now_s=self._clock.time(), + rate_hz=self.hs.config.rc_login_failed_attempts.per_second, + burst_count=self.hs.config.rc_login_failed_attempts.burst_count, + update=False, + ) + # build a list of supported flows flows = [[login_type] for login_type in self._supported_login_types] - result, params, _ = yield self.check_auth(flows, request_body, clientip) + try: + result, params, _ = yield self.check_auth(flows, request_body, clientip) + except LoginError: + # Update the ratelimite to say we failed (`can_do_action` doesn't raise). + self._failed_uia_attempts_ratelimiter.can_do_action( + user_id, + time_now_s=self._clock.time(), + rate_hz=self.hs.config.rc_login_failed_attempts.per_second, + burst_count=self.hs.config.rc_login_failed_attempts.burst_count, + update=True, + ) + raise # find the completed login type for login_type in self._supported_login_types: @@ -501,11 +528,8 @@ class AuthHandler(BaseHandler): multiple matches Raises: - LimitExceededError if the ratelimiter's login requests count for this - user is too high too proceed. UserDeactivatedError if a user is found but is deactivated. """ - self.ratelimit_login_per_account(user_id) res = yield self._find_user_id_and_pwd_hash(user_id) if res is not None: return res[0] @@ -572,8 +596,6 @@ class AuthHandler(BaseHandler): StoreError if there was a problem accessing the database SynapseError if there was a problem with the request LoginError if there was an authentication problem. - LimitExceededError if the ratelimiter's login requests count for this - user is too high too proceed. """ if username.startswith("@"): @@ -581,8 +603,6 @@ class AuthHandler(BaseHandler): else: qualified_user_id = UserID(username, self.hs.hostname).to_string() - self.ratelimit_login_per_account(qualified_user_id) - login_type = login_submission.get("type") known_login_type = False @@ -650,15 +670,6 @@ class AuthHandler(BaseHandler): if not known_login_type: raise SynapseError(400, "Unknown login type %s" % login_type) - # unknown username or invalid password. - self._failed_attempts_ratelimiter.ratelimit( - qualified_user_id.lower(), - time_now_s=self._clock.time(), - rate_hz=self.hs.config.rc_login_failed_attempts.per_second, - burst_count=self.hs.config.rc_login_failed_attempts.burst_count, - update=True, - ) - # We raise a 403 here, but note that if we're doing user-interactive # login, it turns all LoginErrors into a 401 anyway. raise LoginError(403, "Invalid password", errcode=Codes.FORBIDDEN) @@ -710,10 +721,6 @@ class AuthHandler(BaseHandler): Returns: Deferred[unicode] the canonical_user_id, or Deferred[None] if unknown user/bad password - - Raises: - LimitExceededError if the ratelimiter's login requests count for this - user is too high too proceed. """ lookupres = yield self._find_user_id_and_pwd_hash(user_id) if not lookupres: @@ -742,7 +749,7 @@ class AuthHandler(BaseHandler): auth_api.validate_macaroon(macaroon, "login", user_id) except Exception: raise AuthError(403, "Invalid token", errcode=Codes.FORBIDDEN) - self.ratelimit_login_per_account(user_id) + yield self.auth.check_auth_blocking(user_id) return user_id @@ -912,35 +919,6 @@ class AuthHandler(BaseHandler): else: return defer.succeed(False) - def ratelimit_login_per_account(self, user_id): - """Checks whether the process must be stopped because of ratelimiting. - - Checks against two ratelimiters: the generic one for login attempts per - account and the one specific to failed attempts. - - Args: - user_id (unicode): complete @user:id - - Raises: - LimitExceededError if one of the ratelimiters' login requests count - for this user is too high too proceed. - """ - self._failed_attempts_ratelimiter.ratelimit( - user_id.lower(), - time_now_s=self._clock.time(), - rate_hz=self.hs.config.rc_login_failed_attempts.per_second, - burst_count=self.hs.config.rc_login_failed_attempts.burst_count, - update=False, - ) - - self._account_ratelimiter.ratelimit( - user_id.lower(), - time_now_s=self._clock.time(), - rate_hz=self.hs.config.rc_login_account.per_second, - burst_count=self.hs.config.rc_login_account.burst_count, - update=True, - ) - @attr.s class MacaroonGenerator(object): diff --git a/synapse/rest/client/v1/login.py b/synapse/rest/client/v1/login.py index 24a0ce74f2..19eb15003d 100644 --- a/synapse/rest/client/v1/login.py +++ b/synapse/rest/client/v1/login.py @@ -92,8 +92,11 @@ class LoginRestServlet(RestServlet): self.auth_handler = self.hs.get_auth_handler() self.registration_handler = hs.get_registration_handler() self.handlers = hs.get_handlers() + self._clock = hs.get_clock() self._well_known_builder = WellKnownBuilder(hs) self._address_ratelimiter = Ratelimiter() + self._account_ratelimiter = Ratelimiter() + self._failed_attempts_ratelimiter = Ratelimiter() def on_GET(self, request): flows = [] @@ -202,6 +205,16 @@ class LoginRestServlet(RestServlet): # (See add_threepid in synapse/handlers/auth.py) address = address.lower() + # We also apply account rate limiting using the 3PID as a key, as + # otherwise using 3PID bypasses the ratelimiting based on user ID. + self._failed_attempts_ratelimiter.ratelimit( + (medium, address), + time_now_s=self._clock.time(), + rate_hz=self.hs.config.rc_login_failed_attempts.per_second, + burst_count=self.hs.config.rc_login_failed_attempts.burst_count, + update=False, + ) + # Check for login providers that support 3pid login types ( canonical_user_id, @@ -211,7 +224,8 @@ class LoginRestServlet(RestServlet): ) if canonical_user_id: # Authentication through password provider and 3pid succeeded - result = yield self._register_device_with_callback( + + result = yield self._complete_login( canonical_user_id, login_submission, callback_3pid ) return result @@ -225,6 +239,21 @@ class LoginRestServlet(RestServlet): logger.warning( "unknown 3pid identifier medium %s, address %r", medium, address ) + # We mark that we've failed to log in here, as + # `check_password_provider_3pid` might have returned `None` due + # to an incorrect password, rather than the account not + # existing. + # + # If it returned None but the 3PID was bound then we won't hit + # this code path, which is fine as then the per-user ratelimit + # will kick in below. + self._failed_attempts_ratelimiter.can_do_action( + (medium, address), + time_now_s=self._clock.time(), + rate_hz=self.hs.config.rc_login_failed_attempts.per_second, + burst_count=self.hs.config.rc_login_failed_attempts.burst_count, + update=True, + ) raise LoginError(403, "", errcode=Codes.FORBIDDEN) identifier = {"type": "m.id.user", "user": user_id} @@ -236,29 +265,84 @@ class LoginRestServlet(RestServlet): if "user" not in identifier: raise SynapseError(400, "User identifier is missing 'user' key") - canonical_user_id, callback = yield self.auth_handler.validate_login( - identifier["user"], login_submission + if identifier["user"].startswith("@"): + qualified_user_id = identifier["user"] + else: + qualified_user_id = UserID(identifier["user"], self.hs.hostname).to_string() + + # Check if we've hit the failed ratelimit (but don't update it) + self._failed_attempts_ratelimiter.ratelimit( + qualified_user_id.lower(), + time_now_s=self._clock.time(), + rate_hz=self.hs.config.rc_login_failed_attempts.per_second, + burst_count=self.hs.config.rc_login_failed_attempts.burst_count, + update=False, ) - result = yield self._register_device_with_callback( + try: + canonical_user_id, callback = yield self.auth_handler.validate_login( + identifier["user"], login_submission + ) + except LoginError: + # The user has failed to log in, so we need to update the rate + # limiter. Using `can_do_action` avoids us raising a ratelimit + # exception and masking the LoginError. The actual ratelimiting + # should have happened above. + self._failed_attempts_ratelimiter.can_do_action( + qualified_user_id.lower(), + time_now_s=self._clock.time(), + rate_hz=self.hs.config.rc_login_failed_attempts.per_second, + burst_count=self.hs.config.rc_login_failed_attempts.burst_count, + update=True, + ) + raise + + result = yield self._complete_login( canonical_user_id, login_submission, callback ) return result @defer.inlineCallbacks - def _register_device_with_callback(self, user_id, login_submission, callback=None): - """ Registers a device with a given user_id. Optionally run a callback - function after registration has completed. + def _complete_login( + self, user_id, login_submission, callback=None, create_non_existant_users=False + ): + """Called when we've successfully authed the user and now need to + actually login them in (e.g. create devices). This gets called on + all succesful logins. + + Applies the ratelimiting for succesful login attempts against an + account. Args: user_id (str): ID of the user to register. login_submission (dict): Dictionary of login information. callback (func|None): Callback function to run after registration. + create_non_existant_users (bool): Whether to create the user if + they don't exist. Defaults to False. Returns: result (Dict[str,str]): Dictionary of account information after successful registration. """ + + # Before we actually log them in we check if they've already logged in + # too often. This happens here rather than before as we don't + # necessarily know the user before now. + self._account_ratelimiter.ratelimit( + user_id.lower(), + time_now_s=self._clock.time(), + rate_hz=self.hs.config.rc_login_account.per_second, + burst_count=self.hs.config.rc_login_account.burst_count, + update=True, + ) + + if create_non_existant_users: + user_id = yield self.auth_handler.check_user_exists(user_id) + if not user_id: + user_id = yield self.registration_handler.register_user( + localpart=UserID.from_string(user_id).localpart + ) + device_id = login_submission.get("device_id") initial_display_name = login_submission.get("initial_device_display_name") device_id, access_token = yield self.registration_handler.register_device( @@ -285,7 +369,7 @@ class LoginRestServlet(RestServlet): token ) - result = yield self._register_device_with_callback(user_id, login_submission) + result = yield self._complete_login(user_id, login_submission) return result @defer.inlineCallbacks @@ -313,15 +397,8 @@ class LoginRestServlet(RestServlet): raise LoginError(401, "Invalid JWT", errcode=Codes.UNAUTHORIZED) user_id = UserID(user, self.hs.hostname).to_string() - - registered_user_id = yield self.auth_handler.check_user_exists(user_id) - if not registered_user_id: - registered_user_id = yield self.registration_handler.register_user( - localpart=user - ) - - result = yield self._register_device_with_callback( - registered_user_id, login_submission + result = yield self._complete_login( + user_id, login_submission, create_non_existant_users=True ) return result |