Abstract shared SSO code. (#8765)

De-duplicates code between the SAML and OIDC implementations.

1 files changed, 23 insertions, 54 deletions

diff --git a/synapse/handlers/saml_handler.py b/synapse/handlers/saml_handler.py
index fd6c5e9ea8..aee772239a 100644
--- a/synapse/handlers/saml_handler.py
+++ b/synapse/handlers/saml_handler.py
@@ -24,7 +24,8 @@ from saml2.client import Saml2Client
 from synapse.api.errors import SynapseError
 from synapse.config import ConfigError
 from synapse.config.saml2_config import SamlAttributeRequirement
-from synapse.http.server import respond_with_html
+from synapse.handlers._base import BaseHandler
+from synapse.handlers.sso import MappingException
 from synapse.http.servlet import parse_string
 from synapse.http.site import SynapseRequest
 from synapse.module_api import ModuleApi
@@ -42,10 +43,6 @@ if TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
-class MappingException(Exception):
-    """Used to catch errors when mapping the SAML2 response to a user."""
-
-
 @attr.s(slots=True)
 class Saml2SessionData:
     """Data we track about SAML2 sessions"""
@@ -57,17 +54,13 @@ class Saml2SessionData:
     ui_auth_session_id = attr.ib(type=Optional[str], default=None)
 
 
-class SamlHandler:
+class SamlHandler(BaseHandler):
     def __init__(self, hs: "synapse.server.HomeServer"):
-        self.hs = hs
+        super().__init__(hs)
         self._saml_client = Saml2Client(hs.config.saml2_sp_config)
-        self._auth = hs.get_auth()
         self._auth_handler = hs.get_auth_handler()
         self._registration_handler = hs.get_registration_handler()
 
-        self._clock = hs.get_clock()
-        self._datastore = hs.get_datastore()
-        self._hostname = hs.hostname
         self._saml2_session_lifetime = hs.config.saml2_session_lifetime
         self._grandfathered_mxid_source_attribute = (
             hs.config.saml2_grandfathered_mxid_source_attribute
@@ -88,26 +81,9 @@ class SamlHandler:
         self._outstanding_requests_dict = {}  # type: Dict[str, Saml2SessionData]
 
         # a lock on the mappings
-        self._mapping_lock = Linearizer(name="saml_mapping", clock=self._clock)
-
-    def _render_error(
-        self, request, error: str, error_description: Optional[str] = None
-    ) -> None:
-        """Render the error template and respond to the request with it.
+        self._mapping_lock = Linearizer(name="saml_mapping", clock=self.clock)
 
-        This is used to show errors to the user. The template of this page can
-        be found under `synapse/res/templates/sso_error.html`.
-
-        Args:
-            request: The incoming request from the browser.
-                We'll respond with an HTML page describing the error.
-            error: A technical identifier for this error.
-            error_description: A human-readable description of the error.
-        """
-        html = self._error_template.render(
-            error=error, error_description=error_description
-        )
-        respond_with_html(request, 400, html)
+        self._sso_handler = hs.get_sso_handler()
 
     def handle_redirect_request(
         self, client_redirect_url: bytes, ui_auth_session_id: Optional[str] = None
@@ -130,7 +106,7 @@ class SamlHandler:
         # Since SAML sessions timeout it is useful to log when they were created.
         logger.info("Initiating a new SAML session: %s" % (reqid,))
 
-        now = self._clock.time_msec()
+        now = self.clock.time_msec()
         self._outstanding_requests_dict[reqid] = Saml2SessionData(
             creation_time=now, ui_auth_session_id=ui_auth_session_id,
         )
@@ -171,12 +147,12 @@ class SamlHandler:
             # in the (user-visible) exception message, so let's log the exception here
             # so we can track down the session IDs later.
             logger.warning(str(e))
-            self._render_error(
+            self._sso_handler.render_error(
                 request, "unsolicited_response", "Unexpected SAML2 login."
             )
             return
         except Exception as e:
-            self._render_error(
+            self._sso_handler.render_error(
                 request,
                 "invalid_response",
                 "Unable to parse SAML2 response: %s." % (e,),
@@ -184,7 +160,7 @@ class SamlHandler:
             return
 
         if saml2_auth.not_signed:
-            self._render_error(
+            self._sso_handler.render_error(
                 request, "unsigned_respond", "SAML2 response was not signed."
             )
             return
@@ -210,7 +186,7 @@ class SamlHandler:
         # attributes.
         for requirement in self._saml2_attribute_requirements:
             if not _check_attribute_requirement(saml2_auth.ava, requirement):
-                self._render_error(
+                self._sso_handler.render_error(
                     request, "unauthorised", "You are not authorised to log in here."
                 )
                 return
@@ -226,7 +202,7 @@ class SamlHandler:
             )
         except MappingException as e:
             logger.exception("Could not map user")
-            self._render_error(request, "mapping_error", str(e))
+            self._sso_handler.render_error(request, "mapping_error", str(e))
             return
 
         # Complete the interactive auth session or the login.
@@ -274,17 +250,11 @@ class SamlHandler:
 
         with (await self._mapping_lock.queue(self._auth_provider_id)):
             # first of all, check if we already have a mapping for this user
-            logger.info(
-                "Looking for existing mapping for user %s:%s",
-                self._auth_provider_id,
-                remote_user_id,
+            previously_registered_user_id = await self._sso_handler.get_sso_user_by_remote_user_id(
+                self._auth_provider_id, remote_user_id,
             )
-            registered_user_id = await self._datastore.get_user_by_external_id(
-                self._auth_provider_id, remote_user_id
-            )
-            if registered_user_id is not None:
-                logger.info("Found existing mapping %s", registered_user_id)
-                return registered_user_id
+            if previously_registered_user_id:
+                return previously_registered_user_id
 
             # backwards-compatibility hack: see if there is an existing user with a
             # suitable mapping from the uid
@@ -294,7 +264,7 @@ class SamlHandler:
             ):
                 attrval = saml2_auth.ava[self._grandfathered_mxid_source_attribute][0]
                 user_id = UserID(
-                    map_username_to_mxid_localpart(attrval), self._hostname
+                    map_username_to_mxid_localpart(attrval), self.server_name
                 ).to_string()
                 logger.info(
                     "Looking for existing account based on mapped %s %s",
@@ -302,11 +272,11 @@ class SamlHandler:
                     user_id,
                 )
 
-                users = await self._datastore.get_users_by_id_case_insensitive(user_id)
+                users = await self.store.get_users_by_id_case_insensitive(user_id)
                 if users:
                     registered_user_id = list(users.keys())[0]
                     logger.info("Grandfathering mapping to %s", registered_user_id)
-                    await self._datastore.record_user_external_id(
+                    await self.store.record_user_external_id(
                         self._auth_provider_id, remote_user_id, registered_user_id
                     )
                     return registered_user_id
@@ -335,8 +305,8 @@ class SamlHandler:
                 emails = attribute_dict.get("emails", [])
 
                 # Check if this mxid already exists
-                if not await self._datastore.get_users_by_id_case_insensitive(
-                    UserID(localpart, self._hostname).to_string()
+                if not await self.store.get_users_by_id_case_insensitive(
+                    UserID(localpart, self.server_name).to_string()
                 ):
                     # This mxid is free
                     break
@@ -348,7 +318,6 @@ class SamlHandler:
                 )
 
             logger.info("Mapped SAML user to local part %s", localpart)
-
             registered_user_id = await self._registration_handler.register_user(
                 localpart=localpart,
                 default_display_name=displayname,
@@ -356,13 +325,13 @@ class SamlHandler:
                 user_agent_ips=(user_agent, ip_address),
             )
 
-            await self._datastore.record_user_external_id(
+            await self.store.record_user_external_id(
                 self._auth_provider_id, remote_user_id, registered_user_id
             )
             return registered_user_id
 
     def expire_sessions(self):
-        expire_before = self._clock.time_msec() - self._saml2_session_lifetime
+        expire_before = self.clock.time_msec() - self._saml2_session_lifetime
         to_expire = set()
         for reqid, data in self._outstanding_requests_dict.items():
             if data.creation_time < expire_before: