1 files changed, 31 insertions, 0 deletions
diff --git a/synapse/handlers/sso.py b/synapse/handlers/sso.py
index 740df7e4a0..d096e0b091 100644
--- a/synapse/handlers/sso.py
+++ b/synapse/handlers/sso.py
@@ -167,6 +167,37 @@ class SsoHandler:
         """Get the configured identity providers"""
         return self._identity_providers
 
+    async def get_identity_providers_for_user(
+        self, user_id: str
+    ) -> Mapping[str, SsoIdentityProvider]:
+        """Get the SsoIdentityProviders which a user has used
+
+        Given a user id, get the identity providers that that user has used to log in
+        with in the past (and thus could use to re-identify themselves for UI Auth).
+
+        Args:
+            user_id: MXID of user to look up
+
+        Raises:
+            a map of idp_id to SsoIdentityProvider
+        """
+        external_ids = await self._store.get_external_ids_by_user(user_id)
+
+        valid_idps = {}
+        for idp_id, _ in external_ids:
+            idp = self._identity_providers.get(idp_id)
+            if not idp:
+                logger.warning(
+                    "User %r has an SSO mapping for IdP %r, but this is no longer "
+                    "configured.",
+                    user_id,
+                    idp_id,
+                )
+            else:
+                valid_idps[idp_id] = idp
+
+        return valid_idps
+
     def render_error(
         self,
         request: Request,