Merge remote-tracking branch 'origin/develop' into matrix-org-hotfixes

changelog.d/6940.doc

@@ -0,0 +1 @@
+Clean up and update docs on setting up federation.

changelog.d/6948.feature

@@ -0,0 +1 @@
+Implement `GET /_matrix/client/r0/rooms/{roomId}/aliases` endpoint as per [MSC2432](https://github.com/matrix-org/matrix-doc/pull/2432).

changelog.d/6949.feature

@@ -0,0 +1 @@
+Implement `GET /_matrix/client/r0/rooms/{roomId}/aliases` endpoint as per [MSC2432](https://github.com/matrix-org/matrix-doc/pull/2432).

changelog.d/6950.misc

@@ -0,0 +1 @@
+Tiny optimisation for incoming HTTP request dispatch.

changelog.d/6951.misc

@@ -0,0 +1 @@
+Revert #6937.

docs/delegate.md

@@ -0,0 +1,94 @@
+# Delegation
+
+By default, other homeservers will expect to be able to reach yours via
+your `server_name`, on port 8448. For example, if you set your `server_name`
+to `example.com` (so that your user names look like `@user:example.com`),
+other servers will try to connect to yours at `https://example.com:8448/`.
+
+Delegation is a Matrix feature allowing a homeserver admin to retain a
+`server_name` of `example.com` so that user IDs, room aliases, etc continue
+to look like `*:example.com`, whilst having federation traffic routed
+to a different server and/or port (e.g. `synapse.example.com:443`).
+
+## .well-known delegation
+
+To use this method, you need to be able to alter the
+`server_name` 's https server to serve the `/.well-known/matrix/server`
+URL. Having an active server (with a valid TLS certificate) serving your
+`server_name` domain is out of the scope of this documentation.
+
+The URL `https://<server_name>/.well-known/matrix/server` should
+return a JSON structure containing the key `m.server` like so:
+
+```json
+{
+    "m.server": "<synapse.server.name>[:<yourport>]"
+}
+```
+
+In our example, this would mean that URL `https://example.com/.well-known/matrix/server`
+should return:
+
+```json
+{
+    "m.server": "synapse.example.com:443"
+}
+```
+
+Note, specifying a port is optional. If no port is specified, then it defaults
+to 8448.
+
+With .well-known delegation, federating servers will check for a valid TLS
+certificate for the delegated hostname (in our example: `synapse.example.com`).
+
+## SRV DNS record delegation
+
+It is also possible to do delegation using a SRV DNS record. However, that is
+considered an advanced topic since it's a bit complex to set up, and `.well-known`
+delegation is already enough in most cases.
+
+However, if you really need it, you can find some documentation on how such a
+record should look like and how Synapse will use it in [the Matrix
+specification](https://matrix.org/docs/spec/server_server/latest#resolving-server-names).
+
+## Delegation FAQ
+
+### When do I need delegation?
+
+If your homeserver's APIs are accessible on the default federation port (8448)
+and the domain your `server_name` points to, you do not need any delegation.
+
+For instance, if you registered `example.com` and pointed its DNS A record at a
+fresh server, you could install Synapse on that host, giving it a `server_name`
+of `example.com`, and once a reverse proxy has been set up to proxy all requests
+sent to the port `8448` and serve TLS certificates for `example.com`, you
+wouldn't need any delegation set up.
+
+**However**, if your homeserver's APIs aren't accessible on port 8448 and on the
+domain `server_name` points to, you will need to let other servers know how to
+find it using delegation.
+
+### Do you still recommend against using a reverse proxy on the federation port?
+
+We no longer actively recommend against using a reverse proxy. Many admins will
+find it easier to direct federation traffic to a reverse proxy and manage their
+own TLS certificates, and this is a supported configuration.
+
+See [reverse_proxy.md](reverse_proxy.md) for information on setting up a
+reverse proxy.
+
+### Do I still need to give my TLS certificates to Synapse if I am using a reverse proxy?
+
+This is no longer necessary. If you are using a reverse proxy for all of your
+TLS traffic, then you can set `no_tls: True` in the Synapse config.
+
+In that case, the only reason Synapse needs the certificate is to populate a legacy
+`tls_fingerprints` field in the federation API. This is ignored by Synapse 0.99.0
+and later, and the only time pre-0.99 Synapses will check it is when attempting to
+fetch the server keys - and generally this is delegated via `matrix.org`, which
+is running a modern version of Synapse.
+
+### Do I need the same certificate for the client and federation port?
+
+No. There is nothing stopping you from using different certificates,
+particularly if you are using a reverse proxy.

docs/federate.md

@@ -1,163 +1,41 @@
-Setting up Federation
+Setting up federation
 =====================
 
 Federation is the process by which users on different servers can participate
 in the same room. For this to work, those other servers must be able to contact
 yours to send messages.
 
-The ``server_name`` configured in the Synapse configuration file (often
+The `server_name` configured in the Synapse configuration file (often
-``homeserver.yaml``) defines how resources (users, rooms, etc.) will be
+`homeserver.yaml`) defines how resources (users, rooms, etc.) will be
-identified (eg: ``@user:example.com``, ``#room:example.com``). By
+identified (eg: `@user:example.com`, `#room:example.com`). By default,
-default, it is also the domain that other servers will use to
+it is also the domain that other servers will use to try to reach your
-try to reach your server (via port 8448). This is easy to set
+server (via port 8448). This is easy to set up and will work provided
-up and will work provided you set the ``server_name`` to match your
+you set the `server_name` to match your machine's public DNS hostname.
-machine's public DNS hostname, and provide Synapse with a TLS certificate
+
-which is valid for your ``server_name``.
+For this default configuration to work, you will need to listen for TLS
+connections on port 8448. The preferred way to do that is by using a
+reverse proxy: see [reverse_proxy.md](<reverse_proxy.md>) for instructions
+on how to correctly set one up.
+
+In some cases you might not want to run Synapse on the machine that has
+the `server_name` as its public DNS hostname, or you might want federation
+traffic to use a different port than 8448. For example, you might want to
+have your user names look like `@user:example.com`, but you want to run
+Synapse on `synapse.example.com` on port 443. This can be done using
+delegation, which allows an admin to control where federation traffic should
+be sent. See [delegate.md](delegate.md) for instructions on how to set this up.
 
 Once federation has been configured, you should be able to join a room over
-federation. A good place to start is ``#synapse:matrix.org`` - a room for
+federation. A good place to start is `#synapse:matrix.org` - a room for
 Synapse admins.
 
-
-## Delegation
-
-For a more flexible configuration, you can have ``server_name``
-resources (eg: ``@user:example.com``) served by a different host and
-port (eg: ``synapse.example.com:443``). There are two ways to do this:
-
-- adding a ``/.well-known/matrix/server`` URL served on ``https://example.com``.
-- adding a DNS ``SRV`` record in the DNS zone of domain
-  ``example.com``.
-
-Without configuring delegation, the matrix federation will
-expect to find your server via ``example.com:8448``. The following methods
-allow you retain a `server_name` of `example.com` so that your user IDs, room
-aliases, etc continue to look like `*:example.com`, whilst having your
-federation traffic routed to a different server.
-
-### .well-known delegation
-
-To use this method, you need to be able to alter the
-``server_name`` 's https server to serve the ``/.well-known/matrix/server``
-URL. Having an active server (with a valid TLS certificate) serving your
-``server_name`` domain is out of the scope of this documentation.
-
-The URL ``https://<server_name>/.well-known/matrix/server`` should
-return a JSON structure containing the key ``m.server`` like so:
-
-    {
-	    "m.server": "<synapse.server.name>[:<yourport>]"
-    }
-
-In our example, this would mean that URL ``https://example.com/.well-known/matrix/server``
-should return:
-
-    {
-	    "m.server": "synapse.example.com:443"
-    }
-
-Note, specifying a port is optional. If a port is not specified an SRV lookup
-is performed, as described below. If the target of the
-delegation does not have an SRV record, then the port defaults to 8448.
-
-Most installations will not need to configure .well-known. However, it can be
-useful in cases where the admin is hosting on behalf of someone else and
-therefore cannot gain access to the necessary certificate. With .well-known,
-federation servers will check for a valid TLS certificate for the delegated
-hostname (in our example: ``synapse.example.com``).
-
-### DNS SRV delegation
-
-To use this delegation method, you need to have write access to your
-``server_name`` 's domain zone DNS records (in our example it would be
-``example.com`` DNS zone).
-
-This method requires the target server to provide a
-valid TLS certificate for the original ``server_name``.
-
-You need to add a SRV record in your ``server_name`` 's DNS zone with
-this format:
-
-     _matrix._tcp.<yourdomain.com> <ttl> IN SRV <priority> <weight> <port> <synapse.server.name>
-
-In our example, we would need to add this SRV record in the
-``example.com`` DNS zone:
-
-     _matrix._tcp.example.com. 3600 IN SRV 10 5 443 synapse.example.com.
-
-Once done and set up, you can check the DNS record with ``dig -t srv
-_matrix._tcp.<server_name>``. In our example, we would expect this:
-
-    $ dig -t srv _matrix._tcp.example.com
-    _matrix._tcp.example.com. 3600    IN      SRV     10 0 443 synapse.example.com.
-
-Note that the target of a SRV record cannot be an alias (CNAME record): it has to point
-directly to the server hosting the synapse instance.
-
-### Delegation FAQ
-#### When do I need a SRV record or .well-known URI?
-
-If your homeserver listens on the default federation port (8448), and your
-`server_name` points to the host that your homeserver runs on, you do not need an SRV
-record or `.well-known/matrix/server` URI.
-
-For instance, if you registered `example.com` and pointed its DNS A record at a
-fresh server, you could install Synapse on that host,
-giving it a `server_name` of `example.com`, and once [ACME](acme.md) support is enabled,
-it would automatically generate a valid TLS certificate for you via Let's Encrypt
-and no SRV record or .well-known URI would be needed.
-
-**However**, if your server does not listen on port 8448, or if your `server_name`
-does not point to the host that your homeserver runs on, you will need to let
-other servers know how to find it. The way to do this is via .well-known or an
-SRV record.
-
-#### I have created a .well-known URI. Do I also need an SRV record?
-
-No. You can use either `.well-known` delegation or use an SRV record for delegation. You
-do not need to use both to delegate to the same location.
-
-#### Can I manage my own certificates rather than having Synapse renew certificates itself?
-
-Yes, you are welcome to manage your certificates yourself. Synapse will only
-attempt to obtain certificates from Let's Encrypt if you configure it to do
-so.The only requirement is that there is a valid TLS cert present for
-federation end points.
-
-#### Do you still recommend against using a reverse proxy on the federation port?
-
-We no longer actively recommend against using a reverse proxy. Many admins will
-find it easier to direct federation traffic to a reverse proxy and manage their
-own TLS certificates, and this is a supported configuration.
-
-See [reverse_proxy.md](reverse_proxy.md) for information on setting up a
-reverse proxy.
-
-#### Do I still need to give my TLS certificates to Synapse if I am using a reverse proxy?
-
-Practically speaking, this is no longer necessary.
-
-If you are using a reverse proxy for all of your TLS traffic, then you can set
-`no_tls: True` in the Synapse config. In that case, the only reason Synapse
-needs the certificate is to populate a legacy `tls_fingerprints` field in the
-federation API. This is ignored by Synapse 0.99.0 and later, and the only time
-pre-0.99 Synapses will check it is when attempting to fetch the server keys -
-and generally this is delegated via `matrix.org`, which will be running a modern
-version of Synapse.
-
-#### Do I need the same certificate for the client and federation port?
-
-No. There is nothing stopping you from using different certificates,
-particularly if you are using a reverse proxy. However, Synapse will use the
-same certificate on any ports where TLS is configured.
-
 ## Troubleshooting
 
-You can use the [federation tester](
+You can use the [federation tester](https://matrix.org/federationtester)
-<https://matrix.org/federationtester>) to check if your homeserver is
+to check if your homeserver is configured correctly. Alternatively try the
-configured correctly. Alternatively try the [JSON API used by the federation tester](https://matrix.org/federationtester/api/report?server_name=DOMAIN).
+[JSON API used by the federation tester](https://matrix.org/federationtester/api/report?server_name=DOMAIN).
-Note that you'll have to modify this URL to replace ``DOMAIN`` with your
+Note that you'll have to modify this URL to replace `DOMAIN` with your
-``server_name``. Hitting the API directly provides extra detail.
+`server_name`. Hitting the API directly provides extra detail.
 
 The typical failure mode for federation is that when the server tries to join
 a room, it is rejected with "401: Unauthorized". Generally this means that other
@@ -169,8 +47,8 @@ you invite them to. This can be caused by an incorrectly-configured reverse
 proxy: see [reverse_proxy.md](<reverse_proxy.md>) for instructions on how to correctly
 configure a reverse proxy.
 
-## Running a Demo Federation of Synapses
+## Running a demo federation of Synapses
 
 If you want to get up and running quickly with a trio of homeservers in a
-private federation, there is a script in the ``demo`` directory. This is mainly
+private federation, there is a script in the `demo` directory. This is mainly
 useful just for development purposes. See [demo/README](<../demo/README>).

docs/reverse_proxy.md

@@ -18,9 +18,10 @@ When setting up a reverse proxy, remember that Matrix clients and other
 Matrix servers do not necessarily need to connect to your server via the
 same server name or port. Indeed, clients will use port 443 by default,
 whereas servers default to port 8448. Where these are different, we
-refer to the 'client port' and the \'federation port\'. See [Setting
+refer to the 'client port' and the \'federation port\'. See [the Matrix
-up federation](federate.md) for more details of the algorithm used for
+specification](https://matrix.org/docs/spec/server_server/latest#resolving-server-names)
-federation connections.
+for more details of the algorithm used for federation connections, and
+[delegate.md](<delegate.md>) for instructions on setting up delegation.
 
 Let's assume that we expect clients to connect to our server at
 `https://matrix.example.com`, and other servers to connect at

synapse/api/auth.py

@@ -14,6 +14,7 @@
 # limitations under the License.
 
 import logging
+from typing import Optional
 
 from six import itervalues
 
@@ -35,6 +36,7 @@ from synapse.api.errors import (
 )
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS
 from synapse.config.server import is_threepid_reserved
+from synapse.events import EventBase
 from synapse.types import StateMap, UserID
 from synapse.util.caches import CACHE_SIZE_FACTOR, register_cache
 from synapse.util.caches.lrucache import LruCache
@@ -92,20 +94,34 @@ class Auth(object):
         )
 
     @defer.inlineCallbacks
-    def check_joined_room(self, room_id, user_id, current_state=None):
+    def check_user_in_room(
-        """Check if the user is currently joined in the room
+        self,
+        room_id: str,
+        user_id: str,
+        current_state: Optional[StateMap[EventBase]] = None,
+        allow_departed_users: bool = False,
+    ):
+        """Check if the user is in the room, or was at some point.
         Args:
-            room_id(str): The room to check.
+            room_id: The room to check.
-            user_id(str): The user to check.
+
-            current_state(dict): Optional map of the current state of the room.
+            user_id: The user to check.
+
+            current_state: Optional map of the current state of the room.
                 If provided then that map is used to check whether they are a
                 member of the room. Otherwise the current membership is
                 loaded from the database.
+
+            allow_departed_users: if True, accept users that were previously
+                members but have now departed.
+
         Raises:
-            AuthError if the user is not in the room.
+            AuthError if the user is/was not in the room.
         Returns:
-            A deferred membership event for the user if the user is in
+            Deferred[Optional[EventBase]]:
-            the room.
+                Membership event for the user if the user was in the
+                room. This will be the join event if they are currently joined to
+                the room. This will be the leave event if they have left the room.
         """
         if current_state:
             member = current_state.get((EventTypes.Member, user_id), None)
@@ -113,37 +129,19 @@ class Auth(object):
             member = yield self.state.get_current_state(
                 room_id=room_id, event_type=EventTypes.Member, state_key=user_id
             )
-
-        self._check_joined_room(member, user_id, room_id)
-        return member
-
-    @defer.inlineCallbacks
-    def check_user_was_in_room(self, room_id, user_id):
-        """Check if the user was in the room at some point.
-        Args:
-            room_id(str): The room to check.
-            user_id(str): The user to check.
-        Raises:
-            AuthError if the user was never in the room.
-        Returns:
-            A deferred membership event for the user if the user was in the
-            room. This will be the join event if they are currently joined to
-            the room. This will be the leave event if they have left the room.
-        """
-        member = yield self.state.get_current_state(
-            room_id=room_id, event_type=EventTypes.Member, state_key=user_id
-        )
         membership = member.membership if member else None
 
-        if membership not in (Membership.JOIN, Membership.LEAVE):
+        if membership == Membership.JOIN:
-            raise AuthError(403, "User %s not in room %s" % (user_id, room_id))
+            return member
 
-        if membership == Membership.LEAVE:
+        # XXX this looks totally bogus. Why do we not allow users who have been banned,
+        # or those who were members previously and have been re-invited?
+        if allow_departed_users and membership == Membership.LEAVE:
             forgot = yield self.store.did_forget(user_id, room_id)
-            if forgot:
+            if not forgot:
-                raise AuthError(403, "User %s not in room %s" % (user_id, room_id))
+                return member
 
-        return member
+        raise AuthError(403, "User %s not in room %s" % (user_id, room_id))
 
     @defer.inlineCallbacks
     def check_host_in_room(self, room_id, host):
@@ -151,12 +149,6 @@ class Auth(object):
             latest_event_ids = yield self.store.is_host_joined(room_id, host)
             return latest_event_ids
 
-    def _check_joined_room(self, member, user_id, room_id):
-        if not member or member.membership != Membership.JOIN:
-            raise AuthError(
-                403, "User %s not in room %s (%s)" % (user_id, room_id, repr(member))
-            )
-
     def can_federate(self, event, auth_events):
         creation_event = auth_events.get((EventTypes.Create, ""))
 
@@ -560,7 +552,7 @@ class Auth(object):
             return True
 
         user_id = user.to_string()
-        yield self.check_joined_room(room_id, user_id)
+        yield self.check_user_in_room(room_id, user_id)
 
         # We currently require the user is a "moderator" in the room. We do this
         # by checking if they would (theoretically) be able to change the
@@ -633,10 +625,18 @@ class Auth(object):
             return query_params[0].decode("ascii")
 
     @defer.inlineCallbacks
-    def check_in_room_or_world_readable(self, room_id, user_id):
+    def check_user_in_room_or_world_readable(
+        self, room_id: str, user_id: str, allow_departed_users: bool = False
+    ):
         """Checks that the user is or was in the room or the room is world
         readable. If it isn't then an exception is raised.
 
+        Args:
+            room_id: room to check
+            user_id: user to check
+            allow_departed_users: if True, accept users that were previously
+                members but have now departed
+
         Returns:
             Deferred[tuple[str, str|None]]: Resolves to the current membership of
                 the user in the room and the membership event ID of the user. If
@@ -645,12 +645,14 @@ class Auth(object):
         """
 
         try:
-            # check_user_was_in_room will return the most recent membership
+            # check_user_in_room will return the most recent membership
             # event for the user if:
             #  * The user is a non-guest user, and was ever in the room
             #  * The user is a guest user, and has joined the room
             # else it will throw.
-            member_event = yield self.check_user_was_in_room(room_id, user_id)
+            member_event = yield self.check_user_in_room(
+                room_id, user_id, allow_departed_users=allow_departed_users
+            )
             return member_event.membership, member_event.event_id
         except AuthError:
             visibility = yield self.state.get_current_state(
@@ -662,7 +664,9 @@ class Auth(object):
             ):
                 return Membership.JOIN, None
             raise AuthError(
-                403, "Guest access not allowed", errcode=Codes.GUEST_ACCESS_FORBIDDEN
+                403,
+                "User %s not in room %s, and room previews are disabled"
+                % (user_id, room_id),
             )
 
     @defer.inlineCallbacks

synapse/handlers/directory.py

@@ -463,7 +463,9 @@ class DirectoryHandler(BaseHandler):
         # allow access to server admins and current members of the room
         is_admin = await self.auth.is_server_admin(requester.user)
         if not is_admin:
-            await self.auth.check_joined_room(room_id, requester.user.to_string())
+            await self.auth.check_user_in_room_or_world_readable(
+                room_id, requester.user.to_string()
+            )
 
         aliases = await self.store.get_aliases_for_room(room_id)
         return aliases

synapse/handlers/initial_sync.py

@@ -18,7 +18,7 @@ import logging
 from twisted.internet import defer
 
 from synapse.api.constants import EventTypes, Membership
-from synapse.api.errors import AuthError, Codes, SynapseError
+from synapse.api.errors import SynapseError
 from synapse.events.validator import EventValidator
 from synapse.handlers.presence import format_user_presence_state
 from synapse.logging.context import make_deferred_yieldable, run_in_background
@@ -274,8 +274,11 @@ class InitialSyncHandler(BaseHandler):
 
         user_id = requester.user.to_string()
 
-        membership, member_event_id = await self._check_in_room_or_world_readable(
+        (
-            room_id, user_id
+            membership,
+            member_event_id,
+        ) = await self.auth.check_user_in_room_or_world_readable(
+            room_id, user_id, allow_departed_users=True,
         )
         is_peeking = member_event_id is None
 
@@ -433,25 +436,3 @@ class InitialSyncHandler(BaseHandler):
             ret["membership"] = membership
 
         return ret
-
-    async def _check_in_room_or_world_readable(self, room_id, user_id):
-        try:
-            # check_user_was_in_room will return the most recent membership
-            # event for the user if:
-            #  * The user is a non-guest user, and was ever in the room
-            #  * The user is a guest user, and has joined the room
-            # else it will throw.
-            member_event = await self.auth.check_user_was_in_room(room_id, user_id)
-            return member_event.membership, member_event.event_id
-        except AuthError:
-            visibility = await self.state_handler.get_current_state(
-                room_id, EventTypes.RoomHistoryVisibility, ""
-            )
-            if (
-                visibility
-                and visibility.content["history_visibility"] == "world_readable"
-            ):
-                return Membership.JOIN, None
-            raise AuthError(
-                403, "Guest access not allowed", errcode=Codes.GUEST_ACCESS_FORBIDDEN
-            )

synapse/handlers/message.py

@@ -99,7 +99,9 @@ class MessageHandler(object):
         (
             membership,
             membership_event_id,
-        ) = yield self.auth.check_in_room_or_world_readable(room_id, user_id)
+        ) = yield self.auth.check_user_in_room_or_world_readable(
+            room_id, user_id, allow_departed_users=True
+        )
 
         if membership == Membership.JOIN:
             data = yield self.state.get_current_state(room_id, event_type, state_key)
@@ -177,7 +179,9 @@ class MessageHandler(object):
             (
                 membership,
                 membership_event_id,
-            ) = yield self.auth.check_in_room_or_world_readable(room_id, user_id)
+            ) = yield self.auth.check_user_in_room_or_world_readable(
+                room_id, user_id, allow_departed_users=True
+            )
 
             if membership == Membership.JOIN:
                 state_ids = yield self.store.get_filtered_current_state_ids(
@@ -216,8 +220,8 @@ class MessageHandler(object):
         if not requester.app_service:
             # We check AS auth after fetching the room membership, as it
             # requires us to pull out all joined members anyway.
-            membership, _ = yield self.auth.check_in_room_or_world_readable(
+            membership, _ = yield self.auth.check_user_in_room_or_world_readable(
-                room_id, user_id
+                room_id, user_id, allow_departed_users=True
             )
             if membership != Membership.JOIN:
                 raise NotImplementedError(

synapse/handlers/pagination.py

@@ -335,7 +335,9 @@ class PaginationHandler(object):
             (
                 membership,
                 member_event_id,
-            ) = await self.auth.check_in_room_or_world_readable(room_id, user_id)
+            ) = await self.auth.check_user_in_room_or_world_readable(
+                room_id, user_id, allow_departed_users=True
+            )
 
             if source_config.direction == "b":
                 # if we're going backwards, we might need to backfill. This

synapse/handlers/typing.py

@@ -125,7 +125,7 @@ class TypingHandler(object):
         if target_user_id != auth_user_id:
             raise AuthError(400, "Cannot set another user's typing state")
 
-        yield self.auth.check_joined_room(room_id, target_user_id)
+        yield self.auth.check_user_in_room(room_id, target_user_id)
 
         logger.debug("%s has started typing in %s", target_user_id, room_id)
 
@@ -155,7 +155,7 @@ class TypingHandler(object):
         if target_user_id != auth_user_id:
             raise AuthError(400, "Cannot set another user's typing state")
 
-        yield self.auth.check_joined_room(room_id, target_user_id)
+        yield self.auth.check_user_in_room(room_id, target_user_id)
 
         logger.debug("%s has stopped typing in %s", target_user_id, room_id)
 

synapse/http/server.py

@@ -353,10 +353,12 @@ class JsonResource(HttpServer, resource.Resource):
         if request.method == b"OPTIONS":
             return _options_handler, "options_request_handler", {}
 
+        request_path = request.path.decode("ascii")
+
         # Loop through all the registered callbacks to check if the method
         # and path regex match
         for path_entry in self.path_regexs.get(request.method, []):
-            m = path_entry.pattern.match(request.path.decode("ascii"))
+            m = path_entry.pattern.match(request_path)
             if m:
                 # We found a match!
                 return path_entry.callback, path_entry.servlet_classname, m.groupdict()

synapse/rest/client/v1/room.py

@@ -16,6 +16,7 @@
 
 """ This module contains REST servlets to do with rooms: /rooms/<paths> """
 import logging
+import re
 from typing import List, Optional
 
 from six.moves.urllib import parse as urlparse
@@ -848,7 +849,12 @@ class RoomTypingRestServlet(RestServlet):
 
 
 class RoomAliasListServlet(RestServlet):
-    PATTERNS = client_patterns("/rooms/(?P<room_id>[^/]*)/aliases", unstable=False)
+    PATTERNS = [
+        re.compile(
+            r"^/_matrix/client/unstable/org\.matrix\.msc2432"
+            r"/rooms/(?P<room_id>[^/]*)/aliases"
+        ),
+    ]
 
     def __init__(self, hs: "synapse.server.HomeServer"):
         super().__init__()

synapse/rest/client/v2_alpha/relations.py

@@ -142,8 +142,8 @@ class RelationPaginationServlet(RestServlet):
     ):
         requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
-        await self.auth.check_in_room_or_world_readable(
+        await self.auth.check_user_in_room_or_world_readable(
-            room_id, requester.user.to_string()
+            room_id, requester.user.to_string(), allow_departed_users=True
         )
 
         # This gets the original event and checks that a) the event exists and
@@ -235,8 +235,8 @@ class RelationAggregationPaginationServlet(RestServlet):
     ):
         requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
-        await self.auth.check_in_room_or_world_readable(
+        await self.auth.check_user_in_room_or_world_readable(
-            room_id, requester.user.to_string()
+            room_id, requester.user.to_string(), allow_departed_users=True,
         )
 
         # This checks that a) the event exists and b) the user is allowed to
@@ -313,8 +313,8 @@ class RelationAggregationGroupPaginationServlet(RestServlet):
     async def on_GET(self, request, room_id, parent_id, relation_type, event_type, key):
         requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
-        await self.auth.check_in_room_or_world_readable(
+        await self.auth.check_user_in_room_or_world_readable(
-            room_id, requester.user.to_string()
+            room_id, requester.user.to_string(), allow_departed_users=True,
         )
 
         # This checks that a) the event exists and b) the user is allowed to

synapse/rest/client/versions.py

@@ -72,6 +72,8 @@ class VersionsRestServlet(RestServlet):
                     "org.matrix.label_based_filtering": True,
                     # Implements support for cross signing as described in MSC1756
                     "org.matrix.e2e_cross_signing": True,
+                    # Implements additional endpoints as described in MSC2432
+                    "org.matrix.msc2432": True,
                 },
             },
         )

synapse/storage/data_stores/main/event_federation.py

@@ -26,7 +26,6 @@ from synapse.storage._base import SQLBaseStore, make_in_list_sql_clause
 from synapse.storage.data_stores.main.events_worker import EventsWorkerStore
 from synapse.storage.data_stores.main.signatures import SignatureWorkerStore
 from synapse.storage.database import Database
-from synapse.storage.engines import PostgresEngine
 from synapse.util.caches.descriptors import cached
 
 logger = logging.getLogger(__name__)
@@ -67,33 +66,6 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
         else:
             results = set()
 
-        if isinstance(self.database_engine, PostgresEngine):
-            # For efficiency we make the database do this if we can.
-
-            # We need to be a little careful with querying large amounts at
-            # once, for some reason postgres really doesn't like it. We do this
-            # by only asking for auth chain of 500 events at a time.
-            event_ids = list(event_ids)
-            chunks = [event_ids[x : x + 500] for x in range(0, len(event_ids), 500)]
-            for chunk in chunks:
-                sql = """
-                    WITH RECURSIVE auth_chain(event_id) AS (
-                        SELECT auth_id FROM event_auth WHERE event_id = ANY(?)
-                        UNION
-                        SELECT auth_id FROM event_auth
-                        INNER JOIN auth_chain USING (event_id)
-                    )
-                    SELECT event_id FROM auth_chain
-                """
-                txn.execute(sql, (chunk,))
-
-                results.update(event_id for event_id, in txn)
-
-            return list(results)
-
-        # Database doesn't necessarily support recursive CTE, so we fall
-        # back to do doing it manually.
-
         base_sql = "SELECT auth_id FROM event_auth WHERE "
 
         front = set(event_ids)

tests/handlers/test_typing.py

@@ -122,11 +122,11 @@ class TypingNotificationsTestCase(unittest.HomeserverTestCase):
 
         self.room_members = []
 
-        def check_joined_room(room_id, user_id):
+        def check_user_in_room(room_id, user_id):
             if user_id not in [u.to_string() for u in self.room_members]:
                 raise AuthError(401, "User is not in the room")
 
-        hs.get_auth().check_joined_room = check_joined_room
+        hs.get_auth().check_user_in_room = check_user_in_room
 
         def get_joined_hosts_for_room(room_id):
             return set(member.domain for member in self.room_members)

tests/rest/client/v1/test_rooms.py

@@ -1729,8 +1729,7 @@ class ContextTestCase(unittest.HomeserverTestCase):
         self.assertEqual(events_after[1].get("content"), {}, events_after[1])
 
 
-class DirectoryTestCase(unittest.HomeserverTestCase):
+class RoomAliasListTestCase(unittest.HomeserverTestCase):
-
     servlets = [
         synapse.rest.admin.register_servlets_for_client_rest_resource,
         directory.register_servlets,
@@ -1756,6 +1755,16 @@ class DirectoryTestCase(unittest.HomeserverTestCase):
         res = self._get_aliases(user_tok, expected_code=403)
         self.assertEqual(res["errcode"], "M_FORBIDDEN")
 
+    def test_admin_user(self):
+        alias1 = self._random_alias()
+        self._set_alias_via_directory(alias1)
+
+        self.register_user("user", "test", admin=True)
+        user_tok = self.login("user", "test")
+
+        res = self._get_aliases(user_tok)
+        self.assertEqual(res["aliases"], [alias1])
+
     def test_with_aliases(self):
         alias1 = self._random_alias()
         alias2 = self._random_alias()
@@ -1766,11 +1775,29 @@ class DirectoryTestCase(unittest.HomeserverTestCase):
         res = self._get_aliases(self.room_owner_tok)
         self.assertEqual(set(res["aliases"]), {alias1, alias2})
 
+    def test_peekable_room(self):
+        alias1 = self._random_alias()
+        self._set_alias_via_directory(alias1)
+
+        self.helper.send_state(
+            self.room_id,
+            EventTypes.RoomHistoryVisibility,
+            body={"history_visibility": "world_readable"},
+            tok=self.room_owner_tok,
+        )
+
+        self.register_user("user", "test")
+        user_tok = self.login("user", "test")
+
+        res = self._get_aliases(user_tok)
+        self.assertEqual(res["aliases"], [alias1])
+
     def _get_aliases(self, access_token: str, expected_code: int = 200) -> JsonDict:
         """Calls the endpoint under test. returns the json response object."""
         request, channel = self.make_request(
             "GET",
-            "/_matrix/client/r0/rooms/%s/aliases" % (self.room_id,),
+            "/_matrix/client/unstable/org.matrix.msc2432/rooms/%s/aliases"
+            % (self.room_id,),
             access_token=access_token,
         )
         self.render(request)