Record the SSO Auth Provider in the login token (#9510)

This great big stack of commits is a a whole load of hoop-jumping to make it easier to store additional values in login tokens, and then to actually store the SSO Identity Provider in the login token. (Making use of that data will follow in a subsequent PR.)

synapse/api/auth.py

@@ -39,6 +39,7 @@ from synapse.logging import opentracing as opentracing
 from synapse.storage.databases.main.registration import TokenLookupResult
 from synapse.types import StateMap, UserID
 from synapse.util.caches.lrucache import LruCache
+from synapse.util.macaroons import get_value_from_macaroon, satisfy_expiry
 from synapse.util.metrics import Measure
 
 logger = logging.getLogger(__name__)
@@ -408,7 +409,7 @@ class Auth:
             raise _InvalidMacaroonException()
 
         try:
-            user_id = self.get_user_id_from_macaroon(macaroon)
+            user_id = get_value_from_macaroon(macaroon, "user_id")
 
             guest = False
             for caveat in macaroon.caveats:
@@ -416,7 +417,12 @@ class Auth:
                     guest = True
 
             self.validate_macaroon(macaroon, rights, user_id=user_id)
-        except (pymacaroons.exceptions.MacaroonException, TypeError, ValueError):
+        except (
+            pymacaroons.exceptions.MacaroonException,
+            KeyError,
+            TypeError,
+            ValueError,
+        ):
             raise InvalidClientTokenError("Invalid macaroon passed.")
 
         if rights == "access":
@@ -424,27 +430,6 @@ class Auth:
 
         return user_id, guest
 
-    def get_user_id_from_macaroon(self, macaroon):
-        """Retrieve the user_id given by the caveats on the macaroon.
-
-        Does *not* validate the macaroon.
-
-        Args:
-            macaroon (pymacaroons.Macaroon): The macaroon to validate
-
-        Returns:
-            (str) user id
-
-        Raises:
-            InvalidClientCredentialsError if there is no user_id caveat in the
-                macaroon
-        """
-        user_prefix = "user_id = "
-        for caveat in macaroon.caveats:
-            if caveat.caveat_id.startswith(user_prefix):
-                return caveat.caveat_id[len(user_prefix) :]
-        raise InvalidClientTokenError("No user caveat in macaroon")
-
     def validate_macaroon(self, macaroon, type_string, user_id):
         """
         validate that a Macaroon is understood by and was signed by this server.
@@ -465,21 +450,13 @@ class Auth:
         v.satisfy_exact("type = " + type_string)
         v.satisfy_exact("user_id = %s" % user_id)
         v.satisfy_exact("guest = true")
-        v.satisfy_general(self._verify_expiry)
+        satisfy_expiry(v, self.clock.time_msec)
 
         # access_tokens include a nonce for uniqueness: any value is acceptable
         v.satisfy_general(lambda c: c.startswith("nonce = "))
 
         v.verify(macaroon, self._macaroon_secret_key)
 
-    def _verify_expiry(self, caveat):
-        prefix = "time < "
-        if not caveat.startswith(prefix):
-            return False
-        expiry = int(caveat[len(prefix) :])
-        now = self.hs.get_clock().time_msec()
-        return now < expiry
-
     def get_appservice_by_req(self, request: SynapseRequest) -> ApplicationService:
         token = self.get_access_token_from_request(request)
         service = self.store.get_app_service_by_token(token)