From 71f9966f2790c6b24281bb9f109bff28ff05d962 Mon Sep 17 00:00:00 2001 From: Richard van der Hoff <1389908+richvdh@users.noreply.github.com> Date: Mon, 1 Nov 2021 15:10:16 +0000 Subject: [PATCH] Support for serving server well-known files (#11211) Fixes https://github.com/matrix-org/synapse/issues/8308 --- changelog.d/11211.feature | 1 + docs/delegate.md | 82 +++++++++++++++++++---------------- docs/sample_config.yaml | 18 ++++++++ synapse/app/generic_worker.py | 3 ++ synapse/app/homeserver.py | 4 +- synapse/config/server.py | 19 ++++++++ synapse/rest/well_known.py | 47 +++++++++++++++++++- tests/rest/test_well_known.py | 32 +++++++++++--- 8 files changed, 159 insertions(+), 47 deletions(-) create mode 100644 changelog.d/11211.feature diff --git a/changelog.d/11211.feature b/changelog.d/11211.feature new file mode 100644 index 000000000..feeb0cf08 --- /dev/null +++ b/changelog.d/11211.feature @@ -0,0 +1 @@ +Add support for serving `/.well-known/matrix/server` files, to redirect federation traffic to port 443. diff --git a/docs/delegate.md b/docs/delegate.md index f3f89075d..ee9cbb3b1 100644 --- a/docs/delegate.md +++ b/docs/delegate.md @@ -1,4 +1,8 @@ -# Delegation +# Delegation of incoming federation traffic + +In the following documentation, we use the term `server_name` to refer to that setting +in your homeserver configuration file. It appears at the ends of user ids, and tells +other homeservers where they can find your server. 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` @@ -12,13 +16,21 @@ 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. +To use this method, you need to be able to configure the server at +`https://` to serve a file at +`https:///.well-known/matrix/server`. There are two ways to do this, shown below. -The URL `https:///.well-known/matrix/server` should -return a JSON structure containing the key `m.server` like so: +Note that the `.well-known` file is hosted on the default port for `https` (port 443). + +### External server + +For maximum flexibility, you need to configure an external server such as nginx, Apache +or HAProxy to serve the `https:///.well-known/matrix/server` file. Setting +up such a server is out of the scope of this documentation, but note that it is often +possible to configure your [reverse proxy](reverse_proxy.md) for this. + +The URL `https:///.well-known/matrix/server` should be configured +return a JSON structure containing the key `m.server` like this: ```json { @@ -26,8 +38,9 @@ return a JSON structure containing the key `m.server` like so: } ``` -In our example, this would mean that URL `https://example.com/.well-known/matrix/server` -should return: +In our example (where we want federation traffic to be routed to +`https://synapse.example.com`, on port 443), this would mean that +`https://example.com/.well-known/matrix/server` should return: ```json { @@ -38,16 +51,29 @@ should return: 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`). +### Serving a `.well-known/matrix/server` file with Synapse + +If you are able to set up your domain so that `https://` is routed to +Synapse (i.e., the only change needed is to direct federation traffic to port 443 +instead of port 8448), then it is possible to configure Synapse to serve a suitable +`.well-known/matrix/server` file. To do so, add the following to your `homeserver.yaml` +file: + +```yaml +serve_server_wellknown: true +``` + +**Note**: this *only* works if `https://` is routed to Synapse, so is +generally not suitable if Synapse is hosted at a subdomain such as +`https://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. +It is also possible to do delegation using a SRV DNS record. However, that is generally +not recommended, as it can be difficult to configure the TLS certificates correctly in +this case, and it offers little advantage over `.well-known` delegation. -However, if you really need it, you can find some documentation on how such a +However, if you really need it, you can find some documentation on what 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). @@ -68,27 +94,9 @@ wouldn't need any delegation set up. 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? +### Should I use a reverse proxy for federation traffic? -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 [the reverse proxy documentation](reverse_proxy.md) for information on setting up a +Generally, using a reverse proxy for both the federation and client traffic is a good +idea, since it saves handling TLS traffic in Synapse. See +[the reverse proxy documentation](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. diff --git a/docs/sample_config.yaml b/docs/sample_config.yaml index b90ed62d6..c3a4148f7 100644 --- a/docs/sample_config.yaml +++ b/docs/sample_config.yaml @@ -93,6 +93,24 @@ pid_file: DATADIR/homeserver.pid # #public_baseurl: https://example.com/ +# Uncomment the following to tell other servers to send federation traffic on +# port 443. +# +# By default, other servers will try to reach our server on port 8448, which can +# be inconvenient in some environments. +# +# Provided 'https:///' on port 443 is routed to Synapse, this +# option configures Synapse to serve a file at +# 'https:///.well-known/matrix/server'. This will tell other +# servers to send traffic to port 443 instead. +# +# See https://matrix-org.github.io/synapse/latest/delegate.html for more +# information. +# +# Defaults to 'false'. +# +#serve_server_wellknown: true + # Set the soft limit on the number of file descriptors synapse can use # Zero is used to indicate synapse should set the soft limit to the # hard limit. diff --git a/synapse/app/generic_worker.py b/synapse/app/generic_worker.py index 51eadf122..218826741 100644 --- a/synapse/app/generic_worker.py +++ b/synapse/app/generic_worker.py @@ -100,6 +100,7 @@ from synapse.rest.client.register import ( from synapse.rest.health import HealthResource from synapse.rest.key.v2 import KeyApiV2Resource from synapse.rest.synapse.client import build_synapse_client_resource_tree +from synapse.rest.well_known import well_known_resource from synapse.server import HomeServer from synapse.storage.databases.main.censor_events import CensorEventsStore from synapse.storage.databases.main.client_ips import ClientIpWorkerStore @@ -318,6 +319,8 @@ class GenericWorkerServer(HomeServer): resources.update({CLIENT_API_PREFIX: resource}) resources.update(build_synapse_client_resource_tree(self)) + resources.update({"/.well-known": well_known_resource(self)}) + elif name == "federation": resources.update({FEDERATION_PREFIX: TransportLayerServer(self)}) elif name == "media": diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py index 93e229926..336c279a4 100644 --- a/synapse/app/homeserver.py +++ b/synapse/app/homeserver.py @@ -66,7 +66,7 @@ from synapse.rest.admin import AdminRestResource from synapse.rest.health import HealthResource from synapse.rest.key.v2 import KeyApiV2Resource from synapse.rest.synapse.client import build_synapse_client_resource_tree -from synapse.rest.well_known import WellKnownResource +from synapse.rest.well_known import well_known_resource from synapse.server import HomeServer from synapse.storage import DataStore from synapse.util.httpresourcetree import create_resource_tree @@ -189,7 +189,7 @@ class SynapseHomeServer(HomeServer): "/_matrix/client/unstable": client_resource, "/_matrix/client/v2_alpha": client_resource, "/_matrix/client/versions": client_resource, - "/.well-known/matrix/client": WellKnownResource(self), + "/.well-known": well_known_resource(self), "/_synapse/admin": AdminRestResource(self), **build_synapse_client_resource_tree(self), } diff --git a/synapse/config/server.py b/synapse/config/server.py index ed094bdc4..a387fd931 100644 --- a/synapse/config/server.py +++ b/synapse/config/server.py @@ -262,6 +262,7 @@ class ServerConfig(Config): self.print_pidfile = config.get("print_pidfile") self.user_agent_suffix = config.get("user_agent_suffix") self.use_frozen_dicts = config.get("use_frozen_dicts", False) + self.serve_server_wellknown = config.get("serve_server_wellknown", False) self.public_baseurl = config.get("public_baseurl") if self.public_baseurl is not None: @@ -774,6 +775,24 @@ class ServerConfig(Config): # #public_baseurl: https://example.com/ + # Uncomment the following to tell other servers to send federation traffic on + # port 443. + # + # By default, other servers will try to reach our server on port 8448, which can + # be inconvenient in some environments. + # + # Provided 'https:///' on port 443 is routed to Synapse, this + # option configures Synapse to serve a file at + # 'https:///.well-known/matrix/server'. This will tell other + # servers to send traffic to port 443 instead. + # + # See https://matrix-org.github.io/synapse/latest/delegate.html for more + # information. + # + # Defaults to 'false'. + # + #serve_server_wellknown: true + # Set the soft limit on the number of file descriptors synapse can use # Zero is used to indicate synapse should set the soft limit to the # hard limit. diff --git a/synapse/rest/well_known.py b/synapse/rest/well_known.py index 7ac01faab..edbf5ce5d 100644 --- a/synapse/rest/well_known.py +++ b/synapse/rest/well_known.py @@ -21,6 +21,7 @@ from twisted.web.server import Request from synapse.http.server import set_cors_headers from synapse.types import JsonDict from synapse.util import json_encoder +from synapse.util.stringutils import parse_server_name if TYPE_CHECKING: from synapse.server import HomeServer @@ -47,8 +48,8 @@ class WellKnownBuilder: return result -class WellKnownResource(Resource): - """A Twisted web resource which renders the .well-known file""" +class ClientWellKnownResource(Resource): + """A Twisted web resource which renders the .well-known/matrix/client file""" isLeaf = 1 @@ -67,3 +68,45 @@ class WellKnownResource(Resource): logger.debug("returning: %s", r) request.setHeader(b"Content-Type", b"application/json") return json_encoder.encode(r).encode("utf-8") + + +class ServerWellKnownResource(Resource): + """Resource for .well-known/matrix/server, redirecting to port 443""" + + isLeaf = 1 + + def __init__(self, hs: "HomeServer"): + super().__init__() + self._serve_server_wellknown = hs.config.server.serve_server_wellknown + + host, port = parse_server_name(hs.config.server.server_name) + + # If we've got this far, then https:/// must route to us, so + # we just redirect the traffic to port 443 instead of 8448. + if port is None: + port = 443 + + self._response = json_encoder.encode({"m.server": f"{host}:{port}"}).encode( + "utf-8" + ) + + def render_GET(self, request: Request) -> bytes: + if not self._serve_server_wellknown: + request.setResponseCode(404) + request.setHeader(b"Content-Type", b"text/plain") + return b"404. Is anything ever truly *well* known?\n" + + request.setHeader(b"Content-Type", b"application/json") + return self._response + + +def well_known_resource(hs: "HomeServer") -> Resource: + """Returns a Twisted web resource which handles '.well-known' requests""" + res = Resource() + matrix_resource = Resource() + res.putChild(b"matrix", matrix_resource) + + matrix_resource.putChild(b"server", ServerWellKnownResource(hs)) + matrix_resource.putChild(b"client", ClientWellKnownResource(hs)) + + return res diff --git a/tests/rest/test_well_known.py b/tests/rest/test_well_known.py index b2c0279ba..118aa93a3 100644 --- a/tests/rest/test_well_known.py +++ b/tests/rest/test_well_known.py @@ -11,17 +11,19 @@ # 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. +from twisted.web.resource import Resource - -from synapse.rest.well_known import WellKnownResource +from synapse.rest.well_known import well_known_resource from tests import unittest class WellKnownTests(unittest.HomeserverTestCase): def create_test_resource(self): - # replace the JsonResource with a WellKnownResource - return WellKnownResource(self.hs) + # replace the JsonResource with a Resource wrapping the WellKnownResource + res = Resource() + res.putChild(b".well-known", well_known_resource(self.hs)) + return res @unittest.override_config( { @@ -29,7 +31,7 @@ class WellKnownTests(unittest.HomeserverTestCase): "default_identity_server": "https://testis", } ) - def test_well_known(self): + def test_client_well_known(self): channel = self.make_request( "GET", "/.well-known/matrix/client", shorthand=False ) @@ -48,9 +50,27 @@ class WellKnownTests(unittest.HomeserverTestCase): "public_baseurl": None, } ) - def test_well_known_no_public_baseurl(self): + def test_client_well_known_no_public_baseurl(self): channel = self.make_request( "GET", "/.well-known/matrix/client", shorthand=False ) self.assertEqual(channel.code, 404) + + @unittest.override_config({"serve_server_wellknown": True}) + def test_server_well_known(self): + channel = self.make_request( + "GET", "/.well-known/matrix/server", shorthand=False + ) + + self.assertEqual(channel.code, 200) + self.assertEqual( + channel.json_body, + {"m.server": "test:443"}, + ) + + def test_server_well_known_disabled(self): + channel = self.make_request( + "GET", "/.well-known/matrix/server", shorthand=False + ) + self.assertEqual(channel.code, 404)