From 5310808d3bebd17275355ecd474bc013e8c7462d Mon Sep 17 00:00:00 2001 From: Richard van der Hoff Date: Tue, 12 Jan 2021 18:19:42 +0000 Subject: [PATCH] Give the user a better error when they present bad SSO creds If a user tries to do UI Auth via SSO, but uses the wrong account on the SSO IdP, try to give them a better error. Previously, the UIA would claim to be successful, but then the operation in question would simply fail with "auth fail". Instead, serve up an error page which explains the failure. --- changelog.d/9091.feature | 1 + docs/sample_config.yaml | 8 +++++ synapse/config/sso.py | 10 ++++++ synapse/handlers/sso.py | 33 +++++++++++++++++--- synapse/res/templates/sso_auth_bad_user.html | 18 +++++++++++ 5 files changed, 65 insertions(+), 5 deletions(-) create mode 100644 changelog.d/9091.feature create mode 100644 synapse/res/templates/sso_auth_bad_user.html diff --git a/changelog.d/9091.feature b/changelog.d/9091.feature new file mode 100644 index 0000000000..79fcd701f8 --- /dev/null +++ b/changelog.d/9091.feature @@ -0,0 +1 @@ +During user-interactive authentication via single-sign-on, give a better error if the user uses the wrong account on the SSO IdP. diff --git a/docs/sample_config.yaml b/docs/sample_config.yaml index c8ae46d1b3..9da351f9f3 100644 --- a/docs/sample_config.yaml +++ b/docs/sample_config.yaml @@ -1969,6 +1969,14 @@ sso: # # This template has no additional variables. # + # * HTML page shown after a user-interactive authentication session which + # does not map correctly onto the expected user: 'sso_auth_bad_user.html'. + # + # When rendering, this template is given the following variables: + # * server_name: the homeserver's name. + # * user_id_to_verify: the MXID of the user that we are trying to + # validate. + # # * HTML page shown during single sign-on if a deactivated user (according to Synapse's database) # attempts to login: 'sso_account_deactivated.html'. # diff --git a/synapse/config/sso.py b/synapse/config/sso.py index 1aeb1c5c92..366f0d4698 100644 --- a/synapse/config/sso.py +++ b/synapse/config/sso.py @@ -37,6 +37,7 @@ class SSOConfig(Config): self.sso_error_template, sso_account_deactivated_template, sso_auth_success_template, + self.sso_auth_bad_user_template, ) = self.read_templates( [ "sso_login_idp_picker.html", @@ -45,6 +46,7 @@ class SSOConfig(Config): "sso_error.html", "sso_account_deactivated.html", "sso_auth_success.html", + "sso_auth_bad_user.html", ], template_dir, ) @@ -160,6 +162,14 @@ class SSOConfig(Config): # # This template has no additional variables. # + # * HTML page shown after a user-interactive authentication session which + # does not map correctly onto the expected user: 'sso_auth_bad_user.html'. + # + # When rendering, this template is given the following variables: + # * server_name: the homeserver's name. + # * user_id_to_verify: the MXID of the user that we are trying to + # validate. + # # * HTML page shown during single sign-on if a deactivated user (according to Synapse's database) # attempts to login: 'sso_account_deactivated.html'. # diff --git a/synapse/handlers/sso.py b/synapse/handlers/sso.py index d096e0b091..69ffc9d9c2 100644 --- a/synapse/handlers/sso.py +++ b/synapse/handlers/sso.py @@ -23,6 +23,7 @@ from typing_extensions import NoReturn, Protocol from twisted.web.http import Request from synapse.api.errors import Codes, RedirectException, SynapseError +from synapse.handlers.ui_auth import UIAuthSessionDataConstants from synapse.http import get_request_user_agent from synapse.http.server import respond_with_html from synapse.http.site import SynapseRequest @@ -147,6 +148,7 @@ class SsoHandler: self._server_name = hs.hostname self._registration_handler = hs.get_registration_handler() self._error_template = hs.config.sso_error_template + self._bad_user_template = hs.config.sso_auth_bad_user_template self._auth_handler = hs.get_auth_handler() # a lock on the mappings @@ -577,20 +579,41 @@ class SsoHandler: auth_provider_id, remote_user_id, ) + user_id_to_verify = await self._auth_handler.get_session_data( + ui_auth_session_id, UIAuthSessionDataConstants.REQUEST_USER_ID + ) # type: str + if not user_id: logger.warning( "Remote user %s/%s has not previously logged in here: UIA will fail", auth_provider_id, remote_user_id, ) - # Let the UIA flow handle this the same as if they presented creds for a - # different user. - user_id = "" + elif user_id != user_id_to_verify: + logger.warning( + "Remote user %s/%s mapped onto incorrect user %s: UIA will fail", + auth_provider_id, + remote_user_id, + user_id, + ) + else: + # success! + await self._auth_handler.complete_sso_ui_auth( + user_id, ui_auth_session_id, request + ) + return - await self._auth_handler.complete_sso_ui_auth( - user_id, ui_auth_session_id, request + # the user_id didn't match: mark the stage of the authentication as unsuccessful + await self._store.mark_ui_auth_stage_complete( + ui_auth_session_id, LoginType.SSO, "" ) + # render an error page. + html = self._bad_user_template.render( + server_name=self._server_name, user_id_to_verify=user_id_to_verify, + ) + respond_with_html(request, 200, html) + async def check_username_availability( self, localpart: str, session_id: str, ) -> bool: diff --git a/synapse/res/templates/sso_auth_bad_user.html b/synapse/res/templates/sso_auth_bad_user.html new file mode 100644 index 0000000000..3611191bf9 --- /dev/null +++ b/synapse/res/templates/sso_auth_bad_user.html @@ -0,0 +1,18 @@ + + + Authentication Failed + + +
+

+ We were unable to validate your {{server_name | e}} account via + single-sign-on (SSO), because the SSO Identity Provider returned + different details than when you logged in. +

+

+ Try the operation again, and ensure that you use the same details on + the Identity Provider as when you log into your account. +

+
+ +