1 files changed, 16 insertions, 0 deletions
diff --git a/synapse/config/registration.py b/synapse/config/registration.py
index b895c4e9f4..34cb11468c 100644
--- a/synapse/config/registration.py
+++ b/synapse/config/registration.py
@@ -84,6 +84,11 @@ class RegistrationConfig(Config):
             "disable_msisdn_registration", False
         )
 
+        session_lifetime = config.get("session_lifetime")
+        if session_lifetime is not None:
+            session_lifetime = self.parse_duration(session_lifetime)
+        self.session_lifetime = session_lifetime
+
     def generate_config_section(self, generate_secrets=False, **kwargs):
         if generate_secrets:
             registration_shared_secret = 'registration_shared_secret: "%s"' % (
@@ -141,6 +146,17 @@ class RegistrationConfig(Config):
         #  renew_at: 1w
         #  renew_email_subject: "Renew your %%(app)s account"
 
+        # Time that a user's session remains valid for, after they log in.
+        #
+        # Note that this is not currently compatible with guest logins.
+        #
+        # Note also that this is calculated at login time: changes are not applied
+        # retrospectively to users who have already logged in.
+        #
+        # By default, this is infinite.
+        #
+        #session_lifetime: 24h
+
         # The user must provide all of the below types of 3PID when registering.
         #
         #registrations_require_3pid: