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/auth.py b/synapse/handlers/auth.py index 4f881a439a..18cd2b62f0 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 d096e0b091..dcc85e9871 100644 --- a/synapse/handlers/sso.py +++ b/synapse/handlers/sso.py @@ -22,7 +22,9 @@ 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 from synapse.http.server import respond_with_html from synapse.http.site import SynapseRequest @@ -146,8 +148,13 @@ class SsoHandler: self._store = hs.get_datastore() self._server_name = hs.hostname self._registration_handler = hs.get_registration_handler() - self._error_template = hs.config.sso_error_template 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 + + # 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()) @@ -577,20 +584,46 @@ 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! + # Mark the stage of the authentication as successful. + await self._store.mark_ui_auth_stage_complete( + ui_auth_session_id, LoginType.SSO, user_id + ) - await self._auth_handler.complete_sso_ui_auth( - user_id, ui_auth_session_id, request + # 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 + 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. +

+
+ + diff --git a/tests/rest/client/v2_alpha/test_auth.py b/tests/rest/client/v2_alpha/test_auth.py index 5f6ca23b06..50630106ad 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}} + )