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 1/3] 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 000000000..79fcd701f --- /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 c8ae46d1b..9da351f9f 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 1aeb1c5c9..366f0d469 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 d096e0b09..69ffc9d9c 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 000000000..3611191bf --- /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. +

+
+ + From 420031906a04f7b5462347bf47730d4bc6cc8870 Mon Sep 17 00:00:00 2001 From: Richard van der Hoff Date: Wed, 13 Jan 2021 11:12:28 +0000 Subject: [PATCH 2/3] Move `complete_sso_ui_auth` into SSOHandler since we're hacking on this code anyway, may as well move it out of the cluttered AuthHandler. --- synapse/handlers/auth.py | 25 ------------------------- synapse/handlers/sso.py | 16 +++++++++++++--- 2 files changed, 13 insertions(+), 28 deletions(-) diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py index 4f881a439..18cd2b62f 100644 --- a/synapse/handlers/auth.py +++ b/synapse/handlers/auth.py @@ -263,10 +263,6 @@ class AuthHandler(BaseHandler): # authenticating for an operation to occur on their account. self._sso_auth_confirm_template = hs.config.sso_auth_confirm_template - # The following template is shown after a successful user interactive - # authentication session. It tells the user they can close the window. - self._sso_auth_success_template = hs.config.sso_auth_success_template - # The following template is shown during the SSO authentication process if # the account is deactivated. self._sso_account_deactivated_template = ( @@ -1394,27 +1390,6 @@ class AuthHandler(BaseHandler): description=session.description, redirect_url=redirect_url, ) - async def complete_sso_ui_auth( - self, registered_user_id: str, session_id: str, request: Request, - ): - """Having figured out a mxid for this user, complete the HTTP request - - Args: - registered_user_id: The registered user ID to complete SSO login for. - session_id: The ID of the user-interactive auth session. - request: The request to complete. - """ - # Mark the stage of the authentication as successful. - # Save the user who authenticated with SSO, this will be used to ensure - # that the account be modified is also the person who logged in. - await self.store.mark_ui_auth_stage_complete( - session_id, LoginType.SSO, registered_user_id - ) - - # Render the HTML and return. - html = self._sso_auth_success_template - respond_with_html(request, 200, html) - async def complete_sso_login( self, registered_user_id: str, diff --git a/synapse/handlers/sso.py b/synapse/handlers/sso.py index 69ffc9d9c..dcc85e987 100644 --- a/synapse/handlers/sso.py +++ b/synapse/handlers/sso.py @@ -22,6 +22,7 @@ from typing_extensions import NoReturn, Protocol from twisted.web.http import Request +from synapse.api.constants import LoginType from synapse.api.errors import Codes, RedirectException, SynapseError from synapse.handlers.ui_auth import UIAuthSessionDataConstants from synapse.http import get_request_user_agent @@ -147,9 +148,13 @@ class SsoHandler: self._store = hs.get_datastore() self._server_name = hs.hostname self._registration_handler = hs.get_registration_handler() + self._auth_handler = hs.get_auth_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() + + # The following template is shown after a successful user interactive + # authentication session. It tells the user they can close the window. + self._sso_auth_success_template = hs.config.sso_auth_success_template # a lock on the mappings self._mapping_lock = Linearizer(name="sso_user_mapping", clock=hs.get_clock()) @@ -598,9 +603,14 @@ class SsoHandler: ) else: # success! - await self._auth_handler.complete_sso_ui_auth( - user_id, ui_auth_session_id, request + # Mark the stage of the authentication as successful. + await self._store.mark_ui_auth_stage_complete( + ui_auth_session_id, LoginType.SSO, user_id ) + + # Render the HTML confirmation page and return. + html = self._sso_auth_success_template + respond_with_html(request, 200, html) return # the user_id didn't match: mark the stage of the authentication as unsuccessful From 26d10331e5fa33507b680b45c44641e660a3adeb Mon Sep 17 00:00:00 2001 From: Richard van der Hoff Date: Wed, 13 Jan 2021 12:35:23 +0000 Subject: [PATCH 3/3] Add a test for wrong user returned by SSO --- tests/rest/client/v2_alpha/test_auth.py | 27 +++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/tests/rest/client/v2_alpha/test_auth.py b/tests/rest/client/v2_alpha/test_auth.py index 5f6ca23b0..50630106a 100644 --- a/tests/rest/client/v2_alpha/test_auth.py +++ b/tests/rest/client/v2_alpha/test_auth.py @@ -457,3 +457,30 @@ class UIAuthTests(unittest.HomeserverTestCase): self.assertIn({"stages": ["m.login.password"]}, flows) self.assertIn({"stages": ["m.login.sso"]}, flows) self.assertEqual(len(flows), 2) + + @skip_unless(HAS_OIDC, "requires OIDC") + @override_config({"oidc_config": TEST_OIDC_CONFIG}) + def test_ui_auth_fails_for_incorrect_sso_user(self): + """If the user tries to authenticate with the wrong SSO user, they get an error + """ + # log the user in + login_resp = self.helper.login_via_oidc(UserID.from_string(self.user).localpart) + self.assertEqual(login_resp["user_id"], self.user) + + # start a UI Auth flow by attempting to delete a device + channel = self.delete_device(self.user_tok, self.device_id, 401) + + flows = channel.json_body["flows"] + self.assertIn({"stages": ["m.login.sso"]}, flows) + session_id = channel.json_body["session"] + + # do the OIDC auth, but auth as the wrong user + channel = self.helper.auth_via_oidc("wrong_user", ui_auth_session_id=session_id) + + # that should return a failure message + self.assertSubstring("We were unable to validate", channel.text_body) + + # ... and the delete op should now fail with a 403 + self.delete_device( + self.user_tok, self.device_id, 403, body={"auth": {"session": session_id}} + )