p2p: Use a single ed25519 key for event signing/verifying and p2p peer IDs (#885)

* Pass in the private key seed to NewP2PLocalNode to use the same key for p2p

* Extract the ed25519 key from the server name and use it for event checks

This allows HSes which no longer exist to still have events verified for
them. This means that new members can join rooms that has missing servers.

* Remove no-op ipfs uri which we don't use anymore

cmd/dendritejs/keyfetcher.go

@@ -0,0 +1,84 @@
+// Copyright 2020 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.
+
+// +build wasm
+
+package main
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/libp2p/go-libp2p-core/peer"
+	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/matrix-org/util"
+)
+
+const libp2pMatrixKeyID = "ed25519:libp2p-dendrite"
+
+type libp2pKeyFetcher struct {
+}
+
+// FetchKeys looks up a batch of public keys.
+// Takes a map from (server name, key ID) pairs to timestamp.
+// The timestamp is when the keys need to be vaild up to.
+// Returns a map from (server name, key ID) pairs to server key objects for
+// that server name containing that key ID
+// The result may have fewer (server name, key ID) pairs than were in the request.
+// The result may have more (server name, key ID) pairs than were in the request.
+// Returns an error if there was a problem fetching the keys.
+func (f *libp2pKeyFetcher) FetchKeys(
+	ctx context.Context,
+	requests map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.Timestamp,
+) (map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.PublicKeyLookupResult, error) {
+	res := make(map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.PublicKeyLookupResult)
+	for req := range requests {
+		if req.KeyID != libp2pMatrixKeyID {
+			return nil, fmt.Errorf("FetchKeys: cannot fetch key with ID %s, should be %s", req.KeyID, libp2pMatrixKeyID)
+		}
+
+		// The server name is a libp2p peer ID
+		peerIDStr := string(req.ServerName)
+		peerID, err := peer.Decode(peerIDStr)
+		if err != nil {
+			return nil, fmt.Errorf("Failed to decode peer ID from server name '%s': %s", peerIDStr, err)
+		}
+		pubKey, err := peerID.ExtractPublicKey()
+		if err != nil {
+			return nil, fmt.Errorf("Failed to extract public key from peer ID: %s", err)
+		}
+		pubKeyBytes, err := pubKey.Raw()
+		if err != nil {
+			return nil, fmt.Errorf("Failed to extract raw bytes from public key: %s", err)
+		}
+		util.GetLogger(ctx).Info("libp2pKeyFetcher.FetchKeys: Using public key %v for server name %s", pubKeyBytes, req.ServerName)
+
+		b64Key := gomatrixserverlib.Base64String(pubKeyBytes)
+		res[req] = gomatrixserverlib.PublicKeyLookupResult{
+			VerifyKey: gomatrixserverlib.VerifyKey{
+				Key: b64Key,
+			},
+			ExpiredTS:    gomatrixserverlib.PublicKeyNotExpired,
+			ValidUntilTS: gomatrixserverlib.AsTimestamp(time.Now().Add(24 * time.Hour * 365)),
+		}
+	}
+	return res, nil
+}
+
+// FetcherName returns the name of this fetcher, which can then be used for
+// logging errors etc.
+func (f *libp2pKeyFetcher) FetcherName() string {
+	return "libp2pKeyFetcher"
+}

cmd/dendritejs/main.go

@@ -26,7 +26,6 @@ import (
 	"github.com/matrix-org/dendrite/common"
 	"github.com/matrix-org/dendrite/common/basecomponent"
 	"github.com/matrix-org/dendrite/common/config"
-	"github.com/matrix-org/dendrite/common/keydb"
 	"github.com/matrix-org/dendrite/common/transactions"
 	"github.com/matrix-org/dendrite/federationapi"
 	"github.com/matrix-org/dendrite/federationsender"
@@ -69,10 +68,9 @@ func createFederationClient(cfg *config.Dendrite, node *go_http_js_libp2p.P2pLoc
 	return fed
 }
 
-func createP2PNode() (serverName string, node *go_http_js_libp2p.P2pLocalNode) {
-	hosted := "/dns4/ws-star.discovery.libp2p.io/tcp/443/wss/p2p-websocket-star"
-	_ = "/ip4/127.0.0.1/tcp/9090/ws/p2p-websocket-star/"
-	node = go_http_js_libp2p.NewP2pLocalNode("org.matrix.p2p.experiment", []string{hosted})
+func createP2PNode(privKey ed25519.PrivateKey) (serverName string, node *go_http_js_libp2p.P2pLocalNode) {
+	hosted := "/ip4/127.0.0.1/tcp/9090/ws/p2p-websocket-star/"
+	node = go_http_js_libp2p.NewP2pLocalNode("org.matrix.p2p.experiment", privKey.Seed(), []string{hosted})
 	serverName = node.Id
 	fmt.Println("p2p assigned ServerName: ", serverName)
 	return
@@ -95,10 +93,10 @@ func main() {
 	cfg.Matrix.TrustedIDServers = []string{
 		"matrix.org", "vector.im",
 	}
-	cfg.Matrix.KeyID = "ed25519:1337"
+	cfg.Matrix.KeyID = libp2pMatrixKeyID
 	cfg.Matrix.PrivateKey = generateKey()
 
-	serverName, node := createP2PNode()
+	serverName, node := createP2PNode(cfg.Matrix.PrivateKey)
 	cfg.Matrix.ServerName = gomatrixserverlib.ServerName(serverName)
 
 	if err := cfg.Derive(); err != nil {
@@ -111,7 +109,12 @@ func main() {
 	deviceDB := base.CreateDeviceDB()
 	keyDB := base.CreateKeyDB()
 	federation := createFederationClient(cfg, node)
-	keyRing := keydb.CreateKeyRing(federation.Client, keyDB)
+	keyRing := gomatrixserverlib.KeyRing{
+		KeyFetchers: []gomatrixserverlib.KeyFetcher{
+			&libp2pKeyFetcher{},
+		},
+		KeyDatabase: keyDB,
+	}
 
 	alias, input, query := roomserver.SetupRoomServerComponent(base)
 	typingInputAPI := typingserver.SetupTypingServerComponent(base, cache.NewTypingCache())