add option to disable changes to the 3PIDs for an account.

synapse/config/registration.py

@@ -37,6 +37,9 @@ def read_config(self, config):
             "check_is_for_allowed_local_3pids", None
         )
         self.allow_invited_3pids = config.get("allow_invited_3pids", False)
+
+        self.disable_3pid_changes = config.get("disable_3pid_changes", False)
+
         self.registration_shared_secret = config.get("registration_shared_secret")
 
         self.bcrypt_rounds = config.get("bcrypt_rounds", 12)
@@ -89,6 +92,11 @@ def default_config(self, **kwargs):
         #     - medium: msisdn
         #       pattern: "\\+44"
 
+        # If true, stop users from trying to change the 3PIDs associated with
+        # their accounts.
+        #
+        # disable_3pid_changes: False
+
         # If set, allows registration by anyone who also has the shared
         # secret, even if registration is otherwise disabled.
         registration_shared_secret: "%(registration_shared_secret)s"

synapse/rest/client/v2_alpha/account.py

@@ -314,6 +314,9 @@ def on_GET(self, request):
     def on_POST(self, request):
         yield run_on_reactor()
 
+        if self.hs.config.disable_3pid_changes:
+            raise SynapseError(400, "3PID changes disabled on this server")
+
         body = parse_json_object_from_request(request)
 
         threePidCreds = body.get('threePidCreds')
@@ -367,6 +370,9 @@ def __init__(self, hs):
     def on_POST(self, request):
         yield run_on_reactor()
 
+        if self.hs.config.disable_3pid_changes:
+            raise SynapseError(400, "3PID changes disabled on this server")
+
         body = parse_json_object_from_request(request)
 
         required = ['medium', 'address']