Allowing specifying IS to use in unbind API.

By default the homeserver will use the identity server used during the
binding of the 3PID to unbind the 3PID. However, we need to allow
clients to explicitly ask the homeserver to unbind via a particular
identity server, for the case where the 3PID was bound out of band from
the homeserver.

Implements MSC915.

4 files changed, 20 insertions, 8 deletions

diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index 4544de821d..aa5d89a9ac 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -912,7 +912,7 @@ class AuthHandler(BaseHandler):
         )
 
     @defer.inlineCallbacks
-    def delete_threepid(self, user_id, medium, address):
+    def delete_threepid(self, user_id, medium, address, id_server=None):
         """Attempts to unbind the 3pid on the identity servers and deletes it
         from the local database.
 
@@ -920,6 +920,10 @@ class AuthHandler(BaseHandler):
             user_id (str)
             medium (str)
             address (str)
+            id_server (str|None): Use the given identity server when unbinding
+                any threepids. If None then will attempt to unbind using the
+                identity server specified when binding (if known).
+
 
         Returns:
             Deferred[bool]: Returns True if successfully unbound the 3pid on
@@ -937,6 +941,7 @@ class AuthHandler(BaseHandler):
             {
                 'medium': medium,
                 'address': address,
+                'id_server': id_server,
             },
         )
 
diff --git a/synapse/handlers/deactivate_account.py b/synapse/handlers/deactivate_account.py
index 97d3f31d98..101879f89f 100644
--- a/synapse/handlers/deactivate_account.py
+++ b/synapse/handlers/deactivate_account.py
@@ -43,12 +43,15 @@ class DeactivateAccountHandler(BaseHandler):
         hs.get_reactor().callWhenRunning(self._start_user_parting)
 
     @defer.inlineCallbacks
-    def deactivate_account(self, user_id, erase_data):
+    def deactivate_account(self, user_id, erase_data, id_server=None):
         """Deactivate a user's account
 
         Args:
             user_id (str): ID of user to be deactivated
             erase_data (bool): whether to GDPR-erase the user's data
+            id_server (str|None): Use the given identity server when unbinding
+                any threepids. If None then will attempt to unbind using the
+                identity server specified when binding (if known).
 
         Returns:
             Deferred[bool]: True if identity server supports removing
diff --git a/synapse/handlers/identity.py b/synapse/handlers/identity.py
index 765b16d1d9..4c127ba125 100644
--- a/synapse/handlers/identity.py
+++ b/synapse/handlers/identity.py
@@ -159,11 +159,14 @@ class IdentityHandler(BaseHandler):
             Deferred[bool]: True on success, otherwise False if the identity
             server doesn't support unbinding
         """
-        id_servers = yield self.store.get_id_servers_user_bound(
-            user_id=mxid,
-            medium=threepid["medium"],
-            address=threepid["address"],
-        )
+        if threepid.get("id_server"):
+            id_servers = [threepid["id_server"]]
+        else:
+            id_servers = yield self.store.get_id_servers_user_bound(
+                user_id=mxid,
+                medium=threepid["medium"],
+                address=threepid["address"],
+            )
 
         # We don't know where to unbind, so we don't have a choice but to return
         if not id_servers:
diff --git a/synapse/rest/client/v2_alpha/account.py b/synapse/rest/client/v2_alpha/account.py
index 37b32dd37b..50a434a507 100644
--- a/synapse/rest/client/v2_alpha/account.py
+++ b/synapse/rest/client/v2_alpha/account.py
@@ -215,6 +215,7 @@ class DeactivateAccountRestServlet(RestServlet):
         )
         result = yield self._deactivate_account_handler.deactivate_account(
             requester.user.to_string(), erase,
+            id_server=body.get("id_server"),
         )
         if result:
             id_server_unbind_result = "success"
@@ -380,7 +381,7 @@ class ThreepidDeleteRestServlet(RestServlet):
 
         try:
             ret = yield self.auth_handler.delete_threepid(
-                user_id, body['medium'], body['address']
+                user_id, body['medium'], body['address'], body.get("id_server"),
             )
         except Exception:
             # NB. This endpoint should succeed if there is nothing to