Implement MSC1915 - 3PID unbind APIs

changelog.d/4982.misc

@@ -0,0 +1 @@
+Track which identity server is used when binding a threepid and use that for unbinding, as per MSC1915.

synapse/handlers/auth.py

@@ -912,14 +912,18 @@ def add_threepid(self, user_id, medium, address, validated_at):
         )
 
     @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.
 
         Args:
             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 @@ def delete_threepid(self, user_id, medium, address):
             {
                 'medium': medium,
                 'address': address,
+                'id_server': id_server,
             },
         )
 

synapse/handlers/deactivate_account.py

@@ -43,12 +43,15 @@ def __init__(self, hs):
         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
@@ -74,6 +77,7 @@ def deactivate_account(self, user_id, erase_data):
                     {
                         'medium': threepid['medium'],
                         'address': threepid['address'],
+                        'id_server': id_server,
                     },
                 )
                 identity_server_supports_unbinding &= result

synapse/handlers/identity.py

@@ -132,6 +132,14 @@ def bind_threepid(self, creds, mxid):
                 }
             )
             logger.debug("bound threepid %r to %s", creds, mxid)
+
+            # Remember where we bound the threepid
+            yield self.store.add_user_bound_threepid(
+                user_id=mxid,
+                medium=data["medium"],
+                address=data["address"],
+                id_server=id_server,
+            )
         except CodeMessageException as e:
             data = json.loads(e.msg)  # XXX WAT?
         defer.returnValue(data)
@@ -142,30 +150,61 @@ def try_unbind_threepid(self, mxid, threepid):
 
         Args:
             mxid (str): Matrix user ID of binding to be removed
-            threepid (dict): Dict with medium & address of binding to be removed
+            threepid (dict): Dict with medium & address of binding to be
+                removed, and an optional id_server.
 
         Raises:
             SynapseError: If we failed to contact the identity server
 
         Returns:
             Deferred[bool]: True on success, otherwise False if the identity
-            server doesn't support unbinding
+            server doesn't support unbinding (or no identity server found to
+            contact).
         """
-        logger.debug("unbinding threepid %r from %s", threepid, mxid)
-        if not self.trusted_id_servers:
-            logger.warn("Can't unbind threepid: no trusted ID servers set in config")
+        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:
             defer.returnValue(False)
 
-        # We don't track what ID server we added 3pids on (perhaps we ought to)
-        # but we assume that any of the servers in the trusted list are in the
-        # same ID server federation, so we can pick any one of them to send the
-        # deletion request to.
-        id_server = next(iter(self.trusted_id_servers))
+        changed = True
+        for id_server in id_servers:
+            changed &= yield self.try_unbind_threepid_with_id_server(
+                mxid, threepid, id_server,
+            )
+
+        defer.returnValue(changed)
+
+    @defer.inlineCallbacks
+    def try_unbind_threepid_with_id_server(self, mxid, threepid, id_server):
+        """Removes a binding from an identity server
 
+        Args:
+            mxid (str): Matrix user ID of binding to be removed
+            threepid (dict): Dict with medium & address of binding to be removed
+            id_server (str): Identity server to unbind from
+
+        Raises:
+            SynapseError: If we failed to contact the identity server
+
+        Returns:
+            Deferred[bool]: True on success, otherwise False if the identity
+            server doesn't support unbinding
+        """
         url = "https://%s/_matrix/identity/api/v1/3pid/unbind" % (id_server,)
         content = {
             "mxid": mxid,
-            "threepid": threepid,
+            "threepid": {
+                "medium": threepid["medium"],
+                "address": threepid["address"],
+            },
         }
 
         # we abuse the federation http client to sign the request, but we have to send it
@@ -188,16 +227,24 @@ def try_unbind_threepid(self, mxid, threepid):
                 content,
                 headers,
             )
+            changed = True
         except HttpResponseException as e:
+            changed = False
             if e.code in (400, 404, 501,):
                 # The remote server probably doesn't support unbinding (yet)
                 logger.warn("Received %d response while unbinding threepid", e.code)
-                defer.returnValue(False)
             else:
                 logger.error("Failed to unbind threepid on identity server: %s", e)
                 raise SynapseError(502, "Failed to contact identity server")
 
-        defer.returnValue(True)
+        yield self.store.remove_user_bound_threepid(
+            user_id=mxid,
+            medium=threepid["medium"],
+            address=threepid["address"],
+            id_server=id_server,
+        )
+
+        defer.returnValue(changed)
 
     @defer.inlineCallbacks
     def requestEmailToken(self, id_server, email, client_secret, send_attempt, **kwargs):

synapse/rest/client/v2_alpha/account.py

@@ -215,6 +215,7 @@ def on_POST(self, request):
         )
         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"
@@ -363,7 +364,7 @@ def on_POST(self, request):
 
 
 class ThreepidDeleteRestServlet(RestServlet):
-    PATTERNS = client_v2_patterns("/account/3pid/delete$", releases=())
+    PATTERNS = client_v2_patterns("/account/3pid/delete$")
 
     def __init__(self, hs):
         super(ThreepidDeleteRestServlet, self).__init__()
@@ -380,7 +381,7 @@ def on_POST(self, request):
 
         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

synapse/storage/registration.py

@@ -328,6 +328,83 @@ def user_delete_threepid(self, user_id, medium, address):
             desc="user_delete_threepids",
         )
 
+    def add_user_bound_threepid(self, user_id, medium, address, id_server):
+        """The server proxied a bind request to the given identity server on
+        behalf of the given user. We need to remember this in case the user
+        asks us to unbind the threepid.
+
+        Args:
+            user_id (str)
+            medium (str)
+            address (str)
+            id_server (str)
+
+        Returns:
+            Deferred
+        """
+        # We need to use an upsert, in case they user had already bound the
+        # threepid
+        return self._simple_upsert(
+            table="user_threepid_id_server",
+            keyvalues={
+                "user_id": user_id,
+                "medium": medium,
+                "address": address,
+                "id_server": id_server,
+            },
+            values={},
+            insertion_values={},
+            desc="add_user_bound_threepid",
+        )
+
+    def remove_user_bound_threepid(self, user_id, medium, address, id_server):
+        """The server proxied an unbind request to the given identity server on
+        behalf of the given user, so we remove the mapping of threepid to
+        identity server.
+
+        Args:
+            user_id (str)
+            medium (str)
+            address (str)
+            id_server (str)
+
+        Returns:
+            Deferred
+        """
+        return self._simple_delete(
+            table="user_threepid_id_server",
+            keyvalues={
+                "user_id": user_id,
+                "medium": medium,
+                "address": address,
+                "id_server": id_server,
+            },
+            desc="remove_user_bound_threepid",
+        )
+
+    def get_id_servers_user_bound(self, user_id, medium, address):
+        """Get the list of identity servers that the server proxied bind
+        requests to for given user and threepid
+
+        Args:
+            user_id (str)
+            medium (str)
+            address (str)
+
+        Returns:
+            Deferred[list[str]]: Resolves to a list of identity servers
+        """
+        return self._simple_select_onecol(
+            table="user_threepid_id_server",
+            keyvalues={
+                "user_id": user_id,
+                "medium": medium,
+                "address": address,
+            },
+            retcol="id_server",
+            desc="get_id_servers_user_bound",
+        )
+
 
 class RegistrationStore(RegistrationWorkerStore,
                         background_updates.BackgroundUpdateStore):
@@ -356,6 +433,10 @@ def __init__(self, db_conn, hs):
         # clear the background update.
         self.register_noop_background_update("refresh_tokens_device_index")
 
+        self.register_background_update_handler(
+            "user_threepids_grandfather", self._bg_user_threepids_grandfather,
+        )
+
     @defer.inlineCallbacks
     def add_access_token_to_user(self, user_id, token, device_id=None):
         """Adds an access token for the given user.
@@ -738,3 +819,34 @@ def get_user_pending_deactivation(self):
             allow_none=True,
             desc="get_users_pending_deactivation",
         )
+
+    @defer.inlineCallbacks
+    def _bg_user_threepids_grandfather(self, progress, batch_size):
+        """We now track which identity servers a user binds their 3PID to, so
+        we need to handle the case of existing bindings where we didn't track
+        this.
+
+        We do this by grandfathering in existing user threepids assuming that
+        they used one of the server configured trusted identity servers.
+        """
+
+        id_servers = set(self.config.trusted_third_party_id_servers)
+
+        def _bg_user_threepids_grandfather_txn(txn):
+            sql = """
+                INSERT INTO user_threepid_id_server
+                    (user_id, medium, address, id_server)
+                SELECT user_id, medium, address, ?
+                FROM user_threepids
+            """
+
+            txn.executemany(sql, [(id_server,) for id_server in id_servers])
+
+        if id_servers:
+            yield self.runInteraction(
+                "_bg_user_threepids_grandfather", _bg_user_threepids_grandfather_txn,
+            )
+
+        yield self._end_background_update("user_threepids_grandfather")
+
+        defer.returnValue(1)

synapse/storage/schema/delta/53/user_threepid_id.sql

@@ -0,0 +1,29 @@
+/* Copyright 2019 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+-- Tracks which identity server a user bound their threepid via.
+CREATE TABLE user_threepid_id_server (
+    user_id TEXT NOT NULL,
+    medium TEXT NOT NULL,
+    address TEXT NOT NULL,
+    id_server TEXT NOT NULL
+);
+
+CREATE UNIQUE INDEX user_threepid_id_server_idx ON user_threepid_id_server(
+    user_id, medium, address, id_server
+);
+
+INSERT INTO background_updates (update_name, progress_json) VALUES
+  ('user_threepids_grandfather', '{}');