Implement stable support for MSC3882 to allow an existing device/session to generate a login token for use on a new device/session (#15388)

Implements stable support for MSC3882; this involves updating Synapse's support to
match the MSC / the spec says.

Continue to support the unstable version to allow clients to transition.

1 files changed, 10 insertions, 0 deletions

diff --git a/synapse/config/auth.py b/synapse/config/auth.py

index 12e853980e..c7ab428f28 100644
--- a/synapse/config/auth.py
+++ b/synapse/config/auth.py
@@ -60,3 +60,13 @@ class AuthConfig(Config):
         self.ui_auth_session_timeout = self.parse_duration(
             ui_auth.get("session_timeout", 0)
         )
+
+        # Logging in with an existing session.
+        login_via_existing = config.get("login_via_existing_session", {})
+        self.login_via_existing_enabled = login_via_existing.get("enabled", False)
+        self.login_via_existing_require_ui_auth = login_via_existing.get(
+            "require_ui_auth", True
+        )
+        self.login_via_existing_token_timeout = self.parse_duration(
+            login_via_existing.get("token_timeout", "5m")
+        )