From 4c9ed1333f0cdecf4ecccfb47caf11c18795eaf7 Mon Sep 17 00:00:00 2001
From: Till Faelligen <2353100+S7evinK@users.noreply.github.com>
Date: Wed, 7 Sep 2022 09:21:45 +0200
Subject: [PATCH] Add SigningKeyUpdateConsumer

---
 keyserver/consumers/signingkeyupdate.go | 110 ++++++++++++++++++++++++
 keyserver/keyserver.go                  |  10 ++-
 2 files changed, 119 insertions(+), 1 deletion(-)
 create mode 100644 keyserver/consumers/signingkeyupdate.go

diff --git a/keyserver/consumers/signingkeyupdate.go b/keyserver/consumers/signingkeyupdate.go
new file mode 100644
index 000000000..366e259b4
--- /dev/null
+++ b/keyserver/consumers/signingkeyupdate.go
@@ -0,0 +1,110 @@
+// Copyright 2022 The Matrix.org Foundation C.I.C.
+//
+// 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.
+
+package consumers
+
+import (
+	"context"
+	"encoding/json"
+
+	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/nats-io/nats.go"
+	"github.com/sirupsen/logrus"
+
+	keyapi "github.com/matrix-org/dendrite/keyserver/api"
+	"github.com/matrix-org/dendrite/keyserver/internal"
+	"github.com/matrix-org/dendrite/setup/config"
+	"github.com/matrix-org/dendrite/setup/jetstream"
+	"github.com/matrix-org/dendrite/setup/process"
+)
+
+// SigningKeyUpdateConsumer consumes signing key updates that came in over federation.
+type SigningKeyUpdateConsumer struct {
+	ctx       context.Context
+	jetstream nats.JetStreamContext
+	durable   string
+	topic     string
+	keyAPI    *internal.KeyInternalAPI
+	cfg       *config.KeyServer
+}
+
+// NewSigningKeyUpdateConsumer creates a new SigningKeyUpdateConsumer. Call Start() to begin consuming from key servers.
+func NewSigningKeyUpdateConsumer(
+	process *process.ProcessContext,
+	cfg *config.KeyServer,
+	js nats.JetStreamContext,
+	keyAPI *internal.KeyInternalAPI,
+) *SigningKeyUpdateConsumer {
+	return &SigningKeyUpdateConsumer{
+		ctx:       process.Context(),
+		jetstream: js,
+		durable:   cfg.Matrix.JetStream.Prefixed("KeyServerSigningKeyConsumer"),
+		topic:     cfg.Matrix.JetStream.Prefixed(jetstream.InputSigningKeyUpdate),
+		keyAPI:    keyAPI,
+		cfg:       cfg,
+	}
+}
+
+// Start consuming from key servers
+func (t *SigningKeyUpdateConsumer) Start() error {
+	return jetstream.JetStreamConsumer(
+		t.ctx, t.jetstream, t.topic, t.durable, 1,
+		t.onMessage, nats.DeliverAll(), nats.ManualAck(),
+	)
+}
+
+// onMessage is called in response to a message received on the
+// signing key update events topic from the key server.
+func (t *SigningKeyUpdateConsumer) onMessage(ctx context.Context, msgs []*nats.Msg) bool {
+	msg := msgs[0] // Guaranteed to exist if onMessage is called
+	var updatePayload keyapi.CrossSigningKeyUpdate
+	if err := json.Unmarshal(msg.Data, &updatePayload); err != nil {
+		logrus.WithError(err).Errorf("Failed to read from signing key update input topic")
+		return true
+	}
+	origin := gomatrixserverlib.ServerName(msg.Header.Get("origin"))
+	if _, serverName, err := gomatrixserverlib.SplitID('@', updatePayload.UserID); err != nil {
+		logrus.WithError(err).Error("failed to split user id")
+		return true
+	} else if serverName == t.cfg.Matrix.ServerName {
+		logrus.Warn("dropping device key update from ourself")
+		return true
+	} else if serverName != origin {
+		logrus.Warnf("dropping device key update, %s != %s", serverName, origin)
+		return true
+	}
+
+	keys := gomatrixserverlib.CrossSigningKeys{}
+	if updatePayload.MasterKey != nil {
+		keys.MasterKey = *updatePayload.MasterKey
+	}
+	if updatePayload.SelfSigningKey != nil {
+		keys.SelfSigningKey = *updatePayload.SelfSigningKey
+	}
+	uploadReq := &keyapi.PerformUploadDeviceKeysRequest{
+		CrossSigningKeys: keys,
+		UserID:           updatePayload.UserID,
+	}
+	uploadRes := &keyapi.PerformUploadDeviceKeysResponse{}
+	if err := t.keyAPI.PerformUploadDeviceKeys(ctx, uploadReq, uploadRes); err != nil {
+		logrus.WithError(err).Error("failed to upload device keys")
+		return false
+	}
+	if uploadRes.Error != nil {
+		logrus.WithError(uploadRes.Error).Error("failed to upload device keys")
+		return true
+	}
+
+	return true
+}
diff --git a/keyserver/keyserver.go b/keyserver/keyserver.go
index 75cdaedb4..5124b777e 100644
--- a/keyserver/keyserver.go
+++ b/keyserver/keyserver.go
@@ -16,6 +16,8 @@ package keyserver
 
 import (
 	"github.com/gorilla/mux"
+	"github.com/sirupsen/logrus"
+
 	fedsenderapi "github.com/matrix-org/dendrite/federationapi/api"
 	"github.com/matrix-org/dendrite/keyserver/api"
 	"github.com/matrix-org/dendrite/keyserver/consumers"
@@ -26,7 +28,6 @@ import (
 	"github.com/matrix-org/dendrite/setup/base"
 	"github.com/matrix-org/dendrite/setup/config"
 	"github.com/matrix-org/dendrite/setup/jetstream"
-	"github.com/sirupsen/logrus"
 )
 
 // AddInternalRoutes registers HTTP handlers for the internal API. Invokes functions
@@ -72,5 +73,12 @@ func NewInternalAPI(
 		logrus.WithError(err).Panic("failed to start device list consumer")
 	}
 
+	sigConsumer := consumers.NewSigningKeyUpdateConsumer(
+		base.ProcessContext, cfg, js, ap,
+	)
+	if err := sigConsumer.Start(); err != nil {
+		logrus.WithError(err).Panic("failed to start signing key consumer")
+	}
+
 	return ap
 }