Revert "Merge pull request #3431 from matrix-org/rav/erasure_visibility"

This reverts commit ce0d911156b355c5bf452120bfb08653dad96497, reversing
changes made to b4a5d767a94f1680d07edfd583aae54ce422573e.

8 files changed, 26 insertions, 214 deletions

diff --git a/synapse/handlers/deactivate_account.py b/synapse/handlers/deactivate_account.py
index 404b662469..8ec5ba2012 100644
--- a/synapse/handlers/deactivate_account.py
+++ b/synapse/handlers/deactivate_account.py
@@ -42,7 +42,7 @@ class DeactivateAccountHandler(BaseHandler):
         reactor.callWhenRunning(self._start_user_parting)
 
     @defer.inlineCallbacks
-    def deactivate_account(self, user_id, erase_data):
+    def deactivate_account(self, user_id):
         """Deactivate a user's account
 
         Args:
@@ -92,11 +92,6 @@ class DeactivateAccountHandler(BaseHandler):
         # delete from user directory
         yield self.user_directory_handler.handle_user_deactivated(user_id)
 
-        # Mark the user as erased, if they asked for that
-        if erase_data:
-            logger.info("Marking %s as erased", user_id)
-            yield self.store.mark_user_erased(user_id)
-
         # Now start the process that goes through that list and
         # parts users from rooms (if it isn't already running)
         self._start_user_parting()
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 1ca56c2c97..2571758284 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -495,20 +495,7 @@ class FederationHandler(BaseHandler):
             for e_id, key_to_eid in event_to_state_ids.iteritems()
         }
 
-        erased_senders = yield self.store.are_users_erased(
-            e.sender for e in events,
-        )
-
         def redact_disallowed(event, state):
-            # if the sender has been gdpr17ed, always return a redacted
-            # copy of the event.
-            if erased_senders[event.sender]:
-                logger.info(
-                    "Sender of %s has been erased, redacting",
-                    event.event_id,
-                )
-                return prune_event(event)
-
             if not state:
                 return event
 
diff --git a/synapse/rest/client/v1/admin.py b/synapse/rest/client/v1/admin.py
index ddaedb2a8c..b8665a45eb 100644
--- a/synapse/rest/client/v1/admin.py
+++ b/synapse/rest/client/v1/admin.py
@@ -254,9 +254,7 @@ class DeactivateAccountRestServlet(ClientV1RestServlet):
         if not is_admin:
             raise AuthError(403, "You are not a server admin")
 
-        yield self._deactivate_account_handler.deactivate_account(
-            target_user_id, False,
-        )
+        yield self._deactivate_account_handler.deactivate_account(target_user_id)
         defer.returnValue((200, {}))
 
 
diff --git a/synapse/rest/client/v2_alpha/account.py b/synapse/rest/client/v2_alpha/account.py
index 80dbc3c92e..e1281cfbb6 100644
--- a/synapse/rest/client/v2_alpha/account.py
+++ b/synapse/rest/client/v2_alpha/account.py
@@ -1,7 +1,6 @@
 # -*- coding: utf-8 -*-
 # Copyright 2015, 2016 OpenMarket Ltd
 # Copyright 2017 Vector Creations Ltd
-# Copyright 2018 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.
@@ -16,7 +15,6 @@
 # limitations under the License.
 import logging
 
-from six.moves import http_client
 from twisted.internet import defer
 
 from synapse.api.auth import has_access_token
@@ -188,20 +186,13 @@ class DeactivateAccountRestServlet(RestServlet):
     @defer.inlineCallbacks
     def on_POST(self, request):
         body = parse_json_object_from_request(request)
-        erase = body.get("erase", False)
-        if not isinstance(erase, bool):
-            raise SynapseError(
-                http_client.BAD_REQUEST,
-                "Param 'erase' must be a boolean, if given",
-                Codes.BAD_JSON,
-            )
 
         requester = yield self.auth.get_user_by_req(request)
 
         # allow ASes to dectivate their own users
         if requester.app_service:
             yield self._deactivate_account_handler.deactivate_account(
-                requester.user.to_string(), erase,
+                requester.user.to_string()
             )
             defer.returnValue((200, {}))
 
@@ -209,7 +200,7 @@ class DeactivateAccountRestServlet(RestServlet):
             requester, body, self.hs.get_ip_from_request(request),
         )
         yield self._deactivate_account_handler.deactivate_account(
-            requester.user.to_string(), erase,
+            requester.user.to_string(),
         )
         defer.returnValue((200, {}))
 
diff --git a/synapse/storage/__init__.py b/synapse/storage/__init__.py
index e843b702b9..979fa22438 100644
--- a/synapse/storage/__init__.py
+++ b/synapse/storage/__init__.py
@@ -20,7 +20,6 @@ import time
 import logging
 
 from synapse.storage.devices import DeviceStore
-from synapse.storage.user_erasure_store import UserErasureStore
 from .appservice import (
     ApplicationServiceStore, ApplicationServiceTransactionStore
 )
@@ -89,7 +88,6 @@ class DataStore(RoomMemberStore, RoomStore,
                 DeviceInboxStore,
                 UserDirectoryStore,
                 GroupServerStore,
-                UserErasureStore,
                 ):
 
     def __init__(self, db_conn, hs):
diff --git a/synapse/storage/schema/delta/50/erasure_store.sql b/synapse/storage/schema/delta/50/erasure_store.sql
deleted file mode 100644
index 5d8641a9ab..0000000000
--- a/synapse/storage/schema/delta/50/erasure_store.sql
+++ /dev/null
@@ -1,21 +0,0 @@
-/* Copyright 2018 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.
- */
-
--- a table of users who have requested that their details be erased
-CREATE TABLE erased_users (
-    user_id TEXT NOT NULL
-);
-
-CREATE UNIQUE INDEX erased_users_user ON erased_users(user_id);
diff --git a/synapse/storage/user_erasure_store.py b/synapse/storage/user_erasure_store.py
deleted file mode 100644
index 47bfc01e84..0000000000
--- a/synapse/storage/user_erasure_store.py
+++ /dev/null
@@ -1,103 +0,0 @@
-# -*- coding: utf-8 -*-
-# Copyright 2018 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.
-import operator
-
-from twisted.internet import defer
-
-from synapse.storage._base import SQLBaseStore
-from synapse.util.caches.descriptors import cachedList, cached
-
-
-class UserErasureWorkerStore(SQLBaseStore):
-    @cached()
-    def is_user_erased(self, user_id):
-        """
-        Check if the given user id has requested erasure
-
-        Args:
-            user_id (str): full user id to check
-
-        Returns:
-            Deferred[bool]: True if the user has requested erasure
-        """
-        return self._simple_select_onecol(
-            table="erased_users",
-            keyvalues={"user_id": user_id},
-            retcol="1",
-            desc="is_user_erased",
-        ).addCallback(operator.truth)
-
-    @cachedList(
-        cached_method_name="is_user_erased",
-        list_name="user_ids",
-        inlineCallbacks=True,
-    )
-    def are_users_erased(self, user_ids):
-        """
-        Checks which users in a list have requested erasure
-
-        Args:
-            user_ids (iterable[str]): full user id to check
-
-        Returns:
-            Deferred[dict[str, bool]]:
-                for each user, whether the user has requested erasure.
-        """
-        # this serves the dual purpose of (a) making sure we can do len and
-        # iterate it multiple times, and (b) avoiding duplicates.
-        user_ids = tuple(set(user_ids))
-
-        def _get_erased_users(txn):
-            txn.execute(
-                "SELECT user_id FROM erased_users WHERE user_id IN (%s)" % (
-                    ",".join("?" * len(user_ids))
-                ),
-                user_ids,
-            )
-            return set(r[0] for r in txn)
-
-        erased_users = yield self.runInteraction(
-            "are_users_erased", _get_erased_users,
-        )
-        res = dict((u, u in erased_users) for u in user_ids)
-        defer.returnValue(res)
-
-
-class UserErasureStore(UserErasureWorkerStore):
-    def mark_user_erased(self, user_id):
-        """Indicate that user_id wishes their message history to be erased.
-
-        Args:
-            user_id (str): full user_id to be erased
-        """
-        def f(txn):
-            # first check if they are already in the list
-            txn.execute(
-                "SELECT 1 FROM erased_users WHERE user_id = ?",
-                (user_id, )
-            )
-            if txn.fetchone():
-                return
-
-            # they are not already there: do the insert.
-            txn.execute(
-                "INSERT INTO erased_users (user_id) VALUES (?)",
-                (user_id, )
-            )
-
-            self._invalidate_cache_and_stream(
-                txn, self.is_user_erased, (user_id,)
-            )
-        return self.runInteraction("mark_user_erased", f)
diff --git a/synapse/visibility.py b/synapse/visibility.py
index 65d79cf0d0..aef4953c1d 100644
--- a/synapse/visibility.py
+++ b/synapse/visibility.py
@@ -12,17 +12,15 @@
 # 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.
-import itertools
+
 import logging
-import operator
 
 from twisted.internet import defer
 
-from synapse.api.constants import EventTypes, Membership
-from synapse.events.utils import prune_event
-from synapse.util.logcontext import (
-    make_deferred_yieldable, preserve_fn,
-)
+from synapse.api.constants import Membership, EventTypes
+
+from synapse.util.logcontext import make_deferred_yieldable, preserve_fn
+
 
 logger = logging.getLogger(__name__)
 
@@ -97,27 +95,16 @@ def filter_events_for_client(store, user_id, events, is_peeking=False,
         if ignore_dict_content else []
     )
 
-    erased_senders = yield store.are_users_erased((e.sender for e in events))
-
     def allowed(event):
         """
         Args:
             event (synapse.events.EventBase): event to check
-
-        Returns:
-            None|EventBase:
-               None if the user cannot see this event at all
-
-               a redacted copy of the event if they can only see a redacted
-               version
-
-               the original event if they can see it as normal.
         """
         if not event.is_state() and event.sender in ignore_list:
-            return None
+            return False
 
         if event.event_id in always_include_ids:
-            return event
+            return True
 
         state = event_id_to_state[event.event_id]
 
@@ -131,6 +118,10 @@ def filter_events_for_client(store, user_id, events, is_peeking=False,
         if visibility not in VISIBILITY_PRIORITY:
             visibility = "shared"
 
+        # if it was world_readable, it's easy: everyone can read it
+        if visibility == "world_readable":
+            return True
+
         # Always allow history visibility events on boundaries. This is done
         # by setting the effective visibility to the least restrictive
         # of the old vs new.
@@ -164,7 +155,7 @@ def filter_events_for_client(store, user_id, events, is_peeking=False,
             if membership == "leave" and (
                 prev_membership == "join" or prev_membership == "invite"
             ):
-                return event
+                return True
 
             new_priority = MEMBERSHIP_PRIORITY.index(membership)
             old_priority = MEMBERSHIP_PRIORITY.index(prev_membership)
@@ -175,55 +166,31 @@ def filter_events_for_client(store, user_id, events, is_peeking=False,
         if membership is None:
             membership_event = state.get((EventTypes.Member, user_id), None)
             if membership_event:
-                # XXX why do we do this?
-                # https://github.com/matrix-org/synapse/issues/3350
                 if membership_event.event_id not in event_id_forgotten:
                     membership = membership_event.membership
 
         # if the user was a member of the room at the time of the event,
         # they can see it.
         if membership == Membership.JOIN:
-            return event
-
-        # otherwise, it depends on the room visibility.
+            return True
 
         if visibility == "joined":
             # we weren't a member at the time of the event, so we can't
             # see this event.
-            return None
+            return False
 
         elif visibility == "invited":
             # user can also see the event if they were *invited* at the time
             # of the event.
-            return (
-                event if membership == Membership.INVITE else None
-            )
-
-        elif visibility == "shared" and is_peeking:
-            # if the visibility is shared, users cannot see the event unless
-            # they have *subequently* joined the room (or were members at the
-            # time, of course)
+            return membership == Membership.INVITE
+
+        else:
+            # visibility is shared: user can also see the event if they have
+            # become a member since the event
             #
             # XXX: if the user has subsequently joined and then left again,
             # ideally we would share history up to the point they left. But
-            # we don't know when they left. We just treat it as though they
-            # never joined, and restrict access.
-            return None
-
-        # the visibility is either shared or world_readable, and the user was
-        # not a member at the time. We allow it, provided the original sender
-        # has not requested their data to be erased, in which case, we return
-        # a redacted version.
-        if erased_senders[event.sender]:
-            return prune_event(event)
-
-        return event
-
-    # check each event: gives an iterable[None|EventBase]
-    filtered_events = itertools.imap(allowed, events)
-
-    # remove the None entries
-    filtered_events = filter(operator.truth, filtered_events)
+            # we don't know when they left.
+            return not is_peeking
 
-    # we turn it into a list before returning it.
-    defer.returnValue(list(filtered_events))
+    defer.returnValue(list(filter(allowed, events)))