Synapse 1.2.1 (2019-07-26)

==========================
 
 Security update
 ---------------
 
 This release includes *four* security fixes:
 
 - Prevent an attack where a federated server could send redactions for arbitrary events in v1 and v2 rooms. ([\#5767](https://github.com/matrix-org/synapse/issues/5767))
 - Prevent a denial-of-service attack where cycles of redaction events would make Synapse spin infinitely. Thanks to `@lrizika:matrix.org` for identifying and responsibly disclosing this issue. ([0f2ecb961](https://github.com/matrix-org/synapse/commit/0f2ecb961))
 - Prevent an attack where users could be joined or parted from public rooms without their consent. Thanks to @Dylanger for identifying and responsibly disclosing this issue. ([\#5744](https://github.com/matrix-org/synapse/issues/5744))
 - Fix a vulnerability where a federated server could spoof read-receipts from
   users on other servers. Thanks to @Dylanger for identifying this issue too. ([\#5743](https://github.com/matrix-org/synapse/issues/5743))
 
 Additionally, the following fix was in Synapse **1.2.0**, but was not correctly
 identified during the original release:
 
 - It was possible for a room moderator to send a redaction for an `m.room.create` event, which would downgrade the room to version 1. Thanks to `/dev/ponies` for identifying and responsibly disclosing this issue! ([\#5701](https://github.com/matrix-org/synapse/issues/5701))
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Merge tag 'v1.2.1' into shhs

Synapse 1.2.1 (2019-07-26)
==========================

Security update
---------------

This release includes *four* security fixes:

- Prevent an attack where a federated server could send redactions for arbitrary events in v1 and v2 rooms. ([\#5767](https://github.com/matrix-org/synapse/issues/5767))
- Prevent a denial-of-service attack where cycles of redaction events would make Synapse spin infinitely. Thanks to `@lrizika:matrix.org` for identifying and responsibly disclosing this issue. ([0f2ecb961](https://github.com/matrix-org/synapse/commit/0f2ecb961))
- Prevent an attack where users could be joined or parted from public rooms without their consent. Thanks to @Dylanger for identifying and responsibly disclosing this issue. ([\#5744](https://github.com/matrix-org/synapse/issues/5744))
- Fix a vulnerability where a federated server could spoof read-receipts from
  users on other servers. Thanks to @Dylanger for identifying this issue too. ([\#5743](https://github.com/matrix-org/synapse/issues/5743))

Additionally, the following fix was in Synapse **1.2.0**, but was not correctly
identified during the original release:

- It was possible for a room moderator to send a redaction for an `m.room.create` event, which would downgrade the room to version 1. Thanks to `/dev/ponies` for identifying and responsibly disclosing this issue! ([\#5701](https://github.com/matrix-org/synapse/issues/5701))

CHANGES.md

@@ -1,3 +1,22 @@
+Synapse 1.2.1 (2019-07-26)
+==========================
+
+Security update
+---------------
+
+This release includes *four* security fixes:
+
+- Prevent an attack where a federated server could send redactions for arbitrary events in v1 and v2 rooms. ([\#5767](https://github.com/matrix-org/synapse/issues/5767))
+- Prevent a denial-of-service attack where cycles of redaction events would make Synapse spin infinitely. Thanks to `@lrizika:matrix.org` for identifying and responsibly disclosing this issue. ([0f2ecb961](https://github.com/matrix-org/synapse/commit/0f2ecb961))
+- Prevent an attack where users could be joined or parted from public rooms without their consent. Thanks to @Dylanger for identifying and responsibly disclosing this issue. ([\#5744](https://github.com/matrix-org/synapse/issues/5744))
+- Fix a vulnerability where a federated server could spoof read-receipts from
+  users on other servers. Thanks to @Dylanger for identifying this issue too. ([\#5743](https://github.com/matrix-org/synapse/issues/5743))
+
+Additionally, the following fix was in Synapse **1.2.0**, but was not correctly
+identified during the original release:
+
+- It was possible for a room moderator to send a redaction for an `m.room.create` event, which would downgrade the room to version 1. Thanks to `/dev/ponies` for identifying and responsibly disclosing this issue! ([\#5701](https://github.com/matrix-org/synapse/issues/5701))
+
 Synapse 1.2.0 (2019-07-25)
 ==========================
 
@@ -16,6 +35,14 @@ Bugfixes
 Synapse 1.2.0rc1 (2019-07-22)
 =============================
 
+Security fixes
+--------------
+
+This update included a security fix which was initially incorrectly flagged as
+a regular bug fix.
+
+- It was possible for a room moderator to send a redaction for an `m.room.create` event, which would downgrade the room to version 1. Thanks to `/dev/ponies` for identifying and responsibly disclosing this issue! ([\#5701](https://github.com/matrix-org/synapse/issues/5701))
+
 Features
 --------
 
@@ -41,7 +68,6 @@ Bugfixes
 - Fix bug in #5626 that prevented the original_event field from actually having the contents of the original event in a call to `/relations`. ([\#5654](https://github.com/matrix-org/synapse/issues/5654))
 - Fix 3PID bind requests being sent to identity servers as `application/x-form-www-urlencoded` data, which is deprecated. ([\#5658](https://github.com/matrix-org/synapse/issues/5658))
 - Fix some problems with authenticating redactions in recent room versions. ([\#5699](https://github.com/matrix-org/synapse/issues/5699), [\#5700](https://github.com/matrix-org/synapse/issues/5700), [\#5707](https://github.com/matrix-org/synapse/issues/5707))
-- Ignore redactions of m.room.create events. ([\#5701](https://github.com/matrix-org/synapse/issues/5701))
 
 
 Updates to the Docker image

debian/changelog

@@ -1,3 +1,9 @@
+matrix-synapse-py3 (1.2.1) stable; urgency=medium
+
+  * New synapse release 1.2.1.
+
+ -- Synapse Packaging team <packages@matrix.org>  Fri, 26 Jul 2019 11:32:47 +0100
+
 matrix-synapse-py3 (1.2.0) stable; urgency=medium
 
   [ Amber Brown ]

synapse/__init__.py

@@ -35,4 +35,4 @@ try:
 except ImportError:
     pass
 
-__version__ = "1.2.0"
+__version__ = "1.2.1"

synapse/federation/federation_server.py

@@ -369,7 +369,7 @@ class FederationServer(FederationBase):
             logger.warn("Room version %s not in %s", room_version, supported_versions)
             raise IncompatibleRoomVersionError(room_version=room_version)
 
-        pdu = yield self.handler.on_make_join_request(room_id, user_id)
+        pdu = yield self.handler.on_make_join_request(origin, room_id, user_id)
         time_now = self._clock.time_msec()
         defer.returnValue(
             {"event": pdu.get_pdu_json(time_now), "room_version": room_version}
@@ -423,7 +423,7 @@ class FederationServer(FederationBase):
     def on_make_leave_request(self, origin, room_id, user_id):
         origin_host, _ = parse_server_name(origin)
         yield self.check_server_matches_acl(origin_host, room_id)
-        pdu = yield self.handler.on_make_leave_request(room_id, user_id)
+        pdu = yield self.handler.on_make_leave_request(origin, room_id, user_id)
 
         room_version = yield self.store.get_room_version(room_id)
 

synapse/handlers/federation.py

@@ -1204,11 +1204,28 @@ class FederationHandler(BaseHandler):
 
     @defer.inlineCallbacks
     @log_function
-    def on_make_join_request(self, room_id, user_id):
+    def on_make_join_request(self, origin, room_id, user_id):
         """ We've received a /make_join/ request, so we create a partial
         join event for the room and return that. We do *not* persist or
         process it until the other server has signed it and sent it back.
+
+        Args:
+            origin (str): The (verified) server name of the requesting server.
+            room_id (str): Room to create join event in
+            user_id (str): The user to create the join for
+
+        Returns:
+            Deferred[FrozenEvent]
         """
+
+        if get_domain_from_id(user_id) != origin:
+            logger.info(
+                "Got /make_join request for user %r from different origin %s, ignoring",
+                user_id,
+                origin,
+            )
+            raise SynapseError(403, "User not from origin", Codes.FORBIDDEN)
+
         event_content = {"membership": Membership.JOIN}
 
         room_version = yield self.store.get_room_version(room_id)
@@ -1411,11 +1428,27 @@ class FederationHandler(BaseHandler):
 
     @defer.inlineCallbacks
     @log_function
-    def on_make_leave_request(self, room_id, user_id):
+    def on_make_leave_request(self, origin, room_id, user_id):
         """ We've received a /make_leave/ request, so we create a partial
         leave event for the room and return that. We do *not* persist or
         process it until the other server has signed it and sent it back.
+
+        Args:
+            origin (str): The (verified) server name of the requesting server.
+            room_id (str): Room to create leave event in
+            user_id (str): The user to create the leave for
+
+        Returns:
+            Deferred[FrozenEvent]
         """
+        if get_domain_from_id(user_id) != origin:
+            logger.info(
+                "Got /make_leave request for user %r from different origin %s, ignoring",
+                user_id,
+                origin,
+            )
+            raise SynapseError(403, "User not from origin", Codes.FORBIDDEN)
+
         room_version = yield self.store.get_room_version(room_id)
         builder = self.event_builder_factory.new(
             room_version,

synapse/handlers/receipts.py

@@ -17,7 +17,7 @@ import logging
 from twisted.internet import defer
 
 from synapse.handlers._base import BaseHandler
-from synapse.types import ReadReceipt
+from synapse.types import ReadReceipt, get_domain_from_id
 
 logger = logging.getLogger(__name__)
 
@@ -40,7 +40,19 @@ class ReceiptsHandler(BaseHandler):
     def _received_remote_receipt(self, origin, content):
         """Called when we receive an EDU of type m.receipt from a remote HS.
         """
-        receipts = [
+        receipts = []
+        for room_id, room_values in content.items():
+            for receipt_type, users in room_values.items():
+                for user_id, user_values in users.items():
+                    if get_domain_from_id(user_id) != origin:
+                        logger.info(
+                            "Received receipt for user %r from server %s, ignoring",
+                            user_id,
+                            origin,
+                        )
+                        continue
+
+                    receipts.append(
                         ReadReceipt(
                             room_id=room_id,
                             receipt_type=receipt_type,
@@ -48,10 +60,7 @@ class ReceiptsHandler(BaseHandler):
                             event_ids=user_values["event_ids"],
                             data=user_values.get("data", {}),
                         )
-            for room_id, room_values in content.items()
+                    )
-            for receipt_type, users in room_values.items()
-            for user_id, user_values in users.items()
-        ]
 
         yield self._handle_new_receipts(receipts)
 

synapse/storage/events_worker.py

@@ -268,6 +268,14 @@ class EventsWorkerStore(SQLBaseStore):
                     )
                     continue
 
+                if original_event.room_id != entry.event.room_id:
+                    logger.info(
+                        "Withholding redaction %s of event %s from a different room",
+                        event_id,
+                        redacted_event_id,
+                    )
+                    continue
+
                 if entry.event.internal_metadata.need_to_check_redaction():
                     original_domain = get_domain_from_id(original_event.sender)
                     redaction_domain = get_domain_from_id(entry.event.sender)
@@ -629,6 +637,10 @@ class EventsWorkerStore(SQLBaseStore):
             # we choose to ignore redactions of m.room.create events.
             return None
 
+        if original_ev.type == "m.room.redaction":
+            # ... and redaction events
+            return None
+
         redaction_map = yield self._get_events_from_cache_or_db(redactions)
 
         for redaction_id in redactions:
@@ -636,9 +648,21 @@ class EventsWorkerStore(SQLBaseStore):
             if not redaction_entry:
                 # we don't have the redaction event, or the redaction event was not
                 # authorized.
+                logger.debug(
+                    "%s was redacted by %s but redaction not found/authed",
+                    original_ev.event_id,
+                    redaction_id,
+                )
                 continue
 
             redaction_event = redaction_entry.event
+            if redaction_event.room_id != original_ev.room_id:
+                logger.debug(
+                    "%s was redacted by %s but redaction was in a different room!",
+                    original_ev.event_id,
+                    redaction_id,
+                )
+                continue
 
             # Starting in room version v3, some redactions need to be
             # rechecked if we didn't have the redacted event at the
@@ -650,8 +674,15 @@ class EventsWorkerStore(SQLBaseStore):
                     redaction_event.internal_metadata.recheck_redaction = False
                 else:
                     # Senders don't match, so the event isn't actually redacted
+                    logger.debug(
+                        "%s was redacted by %s but the senders don't match",
+                        original_ev.event_id,
+                        redaction_id,
+                    )
                     continue
 
+            logger.debug("Redacting %s due to %s", original_ev.event_id, redaction_id)
+
             # we found a good redaction event. Redact!
             redacted_event = prune_event(original_ev)
             redacted_event.unsigned["redacted_by"] = redaction_id