feat(rln-relay): ensure execution order for pubsub validators

examples/chat2/exec.go

@@ -43,7 +43,7 @@ func execute(options Options) {
 	}
 
 	if options.RLNRelay.Enable {
-		spamHandler := func(message *pb.WakuMessage) error {
+		spamHandler := func(message *pb.WakuMessage, topic string) error {
 			return nil
 		}
 

waku/v2/node/wakunode2.go

@@ -10,7 +10,6 @@ import (
 	backoffv4 "github.com/cenkalti/backoff/v4"
 	golog "github.com/ipfs/go-log/v2"
 	"github.com/libp2p/go-libp2p"
-	pubsub "github.com/libp2p/go-libp2p-pubsub"
 	"go.uber.org/zap"
 
 	"github.com/ethereum/go-ethereum/crypto"
@@ -66,13 +65,13 @@ type IdentityCredential = struct {
 	IDCommitment byte32 `json:"idCommitment"`
 }
 
-type SpamHandler = func(message *pb.WakuMessage) error
+type SpamHandler = func(message *pb.WakuMessage, topic string) error
 
 type RLNRelay interface {
 	IdentityCredential() (IdentityCredential, error)
 	MembershipIndex() uint
 	AppendRLNProof(msg *pb.WakuMessage, senderEpochTime time.Time) error
-	Validator(spamHandler SpamHandler) func(ctx context.Context, peerID peer.ID, message *pubsub.Message) bool
+	Validator(spamHandler SpamHandler) func(ctx context.Context, message *pb.WakuMessage, topic string) bool
 	Start(ctx context.Context) error
 	Stop() error
 }

waku/v2/node/wakunode2_rln.go

@@ -8,7 +8,6 @@ import (
 	"context"
 	"errors"
 
-	pubsub "github.com/libp2p/go-libp2p-pubsub"
 	"github.com/waku-org/go-waku/waku/v2/protocol/rln"
 	"github.com/waku-org/go-waku/waku/v2/protocol/rln/group_manager"
 	"github.com/waku-org/go-waku/waku/v2/protocol/rln/group_manager/dynamic"
@@ -29,6 +28,10 @@ func (w *WakuNode) setupRLNRelay() error {
 		return nil
 	}
 
+	if !w.opts.enableRelay {
+		return errors.New("rln requires relay")
+	}
+
 	var groupManager group_manager.GroupManager
 
 	rlnInstance, rootTracker, err := rln.GetRLNInstanceAndRootTracker(w.opts.rlnTreePath)
@@ -85,8 +88,7 @@ func (w *WakuNode) setupRLNRelay() error {
 
 	w.rlnRelay = rlnRelay
 
-	// Adding RLN as a default validator
-	w.opts.pubsubOpts = append(w.opts.pubsubOpts, pubsub.WithDefaultValidator(rlnRelay.Validator(w.opts.rlnSpamHandler)))
+	w.Relay().RegisterDefaultValidator(w.rlnRelay.Validator(w.opts.rlnSpamHandler))
 
 	return nil
 }

waku/v2/node/wakuoptions.go

@@ -96,7 +96,7 @@ type WakuNodeParameters struct {
 	enableRLN                    bool
 	rlnRelayMemIndex             *uint
 	rlnRelayDynamic              bool
-	rlnSpamHandler               func(message *pb.WakuMessage) error
+	rlnSpamHandler               func(message *pb.WakuMessage, topic string) error
 	rlnETHClientAddress          string
 	keystorePath                 string
 	keystorePassword             string

waku/v2/protocol/envelope.go

@@ -20,12 +20,12 @@ type Envelope struct {
 // as well as generating a hash based on the bytes that compose the message
 func NewEnvelope(msg *wpb.WakuMessage, receiverTime int64, pubSubTopic string) *Envelope {
 	messageHash := msg.Hash(pubSubTopic)
-	hash := hash.SHA256([]byte(msg.ContentTopic), msg.Payload)
+	digest := hash.SHA256([]byte(msg.ContentTopic), msg.Payload)
 	return &Envelope{
 		msg:  msg,
 		hash: messageHash,
 		index: &pb.Index{
-			Digest:       hash[:],
+			Digest:       digest[:],
 			ReceiverTime: receiverTime,
 			SenderTime:   msg.Timestamp,
 			PubsubTopic:  pubSubTopic,

waku/v2/protocol/relay/validators.go

@@ -10,14 +10,14 @@ import (
 
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/crypto/secp256k1"
-
 	pubsub "github.com/libp2p/go-libp2p-pubsub"
 	"github.com/libp2p/go-libp2p/core/peer"
+	proto "google.golang.org/protobuf/proto"
+
 	"github.com/waku-org/go-waku/waku/v2/hash"
 	"github.com/waku-org/go-waku/waku/v2/protocol/pb"
 	"github.com/waku-org/go-waku/waku/v2/timesource"
 	"go.uber.org/zap"
-	proto "google.golang.org/protobuf/proto"
 )
 
 func msgHash(pubSubTopic string, msg *pb.WakuMessage) []byte {
@@ -38,54 +38,60 @@ func msgHash(pubSubTopic string, msg *pb.WakuMessage) []byte {
 	)
 }
 
-const messageWindowDuration = time.Minute * 5
+type validatorFn = func(ctx context.Context, msg *pb.WakuMessage, topic string) bool
 
-func withinTimeWindow(t timesource.Timesource, msg *pb.WakuMessage) bool {
-	if msg.Timestamp == 0 {
-		return false
-	}
+func (w *WakuRelay) RegisterDefaultValidator(fn validatorFn) {
+	w.topicValidatorMutex.Lock()
+	defer w.topicValidatorMutex.Unlock()
+	w.defaultTopicValidators = append(w.defaultTopicValidators, fn)
+}
 
-	now := t.Now()
-	msgTime := time.Unix(0, msg.Timestamp)
+func (w *WakuRelay) RegisterTopicValidator(topic string, fn validatorFn) {
+	w.topicValidatorMutex.Lock()
+	defer w.topicValidatorMutex.Unlock()
 
-	return now.Sub(msgTime).Abs() <= messageWindowDuration
+	w.topicValidators[topic] = append(w.topicValidators[topic], fn)
 }
 
-type validatorFn = func(ctx context.Context, peerID peer.ID, message *pubsub.Message) bool
+func (w *WakuRelay) RemoveTopicValidator(topic string) {
+	w.topicValidatorMutex.Lock()
+	defer w.topicValidatorMutex.Unlock()
 
-func validatorFnBuilder(t timesource.Timesource, topic string, publicKey *ecdsa.PublicKey) (validatorFn, error) {
-	publicKeyBytes := crypto.FromECDSAPub(publicKey)
+	delete(w.topicValidators, topic)
+}
+
+func (w *WakuRelay) topicValidator(topic string) func(ctx context.Context, peerID peer.ID, message *pubsub.Message) bool {
 	return func(ctx context.Context, peerID peer.ID, message *pubsub.Message) bool {
 		msg := new(pb.WakuMessage)
 		err := proto.Unmarshal(message.Data, msg)
 		if err != nil {
 			return false
 		}
 
-		if !withinTimeWindow(t, msg) {
-			return false
+		w.topicValidatorMutex.RLock()
+		validators, exists := w.topicValidators[topic]
+		validators = append(validators, w.defaultTopicValidators...)
+		w.topicValidatorMutex.RUnlock()
+
+		if exists {
+			for _, v := range validators {
+				if !v(ctx, msg, topic) {
+					return false
+				}
+			}
 		}
 
-		msgHash := msgHash(topic, msg)
-		signature := msg.Meta
-
-		return secp256k1.VerifySignature(publicKeyBytes, msgHash, signature)
-	}, nil
+		return true
+	}
 }
 
 // AddSignedTopicValidator registers a gossipsub validator for a topic which will check that messages Meta field contains a valid ECDSA signature for the specified pubsub topic. This is used as a DoS prevention mechanism
 func (w *WakuRelay) AddSignedTopicValidator(topic string, publicKey *ecdsa.PublicKey) error {
 	w.log.Info("adding validator to signed topic", zap.String("topic", topic), zap.String("publicKey", hex.EncodeToString(elliptic.Marshal(publicKey.Curve, publicKey.X, publicKey.Y))))
 
-	fn, err := validatorFnBuilder(w.timesource, topic, publicKey)
-	if err != nil {
-		return err
-	}
+	fn := signedTopicBuilder(w.timesource, publicKey)
 
-	err = w.pubsub.RegisterTopicValidator(topic, fn)
-	if err != nil {
-		return err
-	}
+	w.RegisterTopicValidator(topic, fn)
 
 	if !w.IsSubscribed(topic) {
 		w.log.Warn("relay is not subscribed to signed topic", zap.String("topic", topic))
@@ -94,6 +100,33 @@ func (w *WakuRelay) AddSignedTopicValidator(topic string, publicKey *ecdsa.Publi
 	return nil
 }
 
+const messageWindowDuration = time.Minute * 5
+
+func withinTimeWindow(t timesource.Timesource, msg *pb.WakuMessage) bool {
+	if msg.Timestamp == 0 {
+		return false
+	}
+
+	now := t.Now()
+	msgTime := time.Unix(0, msg.Timestamp)
+
+	return now.Sub(msgTime).Abs() <= messageWindowDuration
+}
+
+func signedTopicBuilder(t timesource.Timesource, publicKey *ecdsa.PublicKey) validatorFn {
+	publicKeyBytes := crypto.FromECDSAPub(publicKey)
+	return func(ctx context.Context, msg *pb.WakuMessage, topic string) bool {
+		if !withinTimeWindow(t, msg) {
+			return false
+		}
+
+		msgHash := msgHash(topic, msg)
+		signature := msg.Meta
+
+		return secp256k1.VerifySignature(publicKeyBytes, msgHash, signature)
+	}
+}
+
 // SignMessage adds an ECDSA signature to a WakuMessage as an opt-in mechanism for DoS prevention
 func SignMessage(privKey *ecdsa.PrivateKey, msg *pb.WakuMessage, pubsubTopic string) error {
 	msgHash := msgHash(pubsubTopic, msg)

waku/v2/protocol/relay/validators_test.go

@@ -7,11 +7,8 @@ import (
 	"time"
 
 	"github.com/ethereum/go-ethereum/crypto"
-	pubsub "github.com/libp2p/go-libp2p-pubsub"
-	pubsub_pb "github.com/libp2p/go-libp2p-pubsub/pb"
 	"github.com/stretchr/testify/require"
 	"github.com/waku-org/go-waku/waku/v2/protocol/pb"
-	"google.golang.org/protobuf/proto"
 )
 
 type FakeTimesource struct {
@@ -59,39 +56,23 @@ func TestMsgHash(t *testing.T) {
 	//	expectedSignature, _ := hex.DecodeString("127FA211B2514F0E974A055392946DC1A14052182A6ABEFB8A6CD7C51DA1BF2E40595D28EF1A9488797C297EED3AAC45430005FB3A7F037BDD9FC4BD99F59E63")
 	//	require.True(t, bytes.Equal(expectedSignature, msg.Meta))
 
-	msgData, _ := proto.Marshal(msg)
-
 	//expectedMessageHash, _ := hex.DecodeString("662F8C20A335F170BD60ABC1F02AD66F0C6A6EE285DA2A53C95259E7937C0AE9")
 	//messageHash := MsgHash(pubsubTopic, msg)
 	//require.True(t, bytes.Equal(expectedMessageHash, messageHash))
 
-	myValidator, err := validatorFnBuilder(NewFakeTimesource(timestamp), protectedPubSubTopic, &prvKey.PublicKey)
-	require.NoError(t, err)
-	result := myValidator(context.Background(), "", &pubsub.Message{
-		Message: &pubsub_pb.Message{
-			Data: msgData,
-		},
-	})
+	myValidator := signedTopicBuilder(NewFakeTimesource(timestamp), &prvKey.PublicKey)
+	result := myValidator(context.Background(), msg, protectedPubSubTopic)
 	require.True(t, result)
 
 	// Exceed 5m window in both directions
 	now5m1sInPast := timestamp.Add(-5 * time.Minute).Add(-1 * time.Second)
-	myValidator, err = validatorFnBuilder(NewFakeTimesource(now5m1sInPast), protectedPubSubTopic, &prvKey.PublicKey)
+	myValidator = signedTopicBuilder(NewFakeTimesource(now5m1sInPast), &prvKey.PublicKey)
 	require.NoError(t, err)
-	result = myValidator(context.Background(), "", &pubsub.Message{
-		Message: &pubsub_pb.Message{
-			Data: msgData,
-		},
-	})
+	result = myValidator(context.Background(), msg, protectedPubSubTopic)
 	require.False(t, result)
 
 	now5m1sInFuture := timestamp.Add(5 * time.Minute).Add(1 * time.Second)
-	myValidator, err = validatorFnBuilder(NewFakeTimesource(now5m1sInFuture), protectedPubSubTopic, &prvKey.PublicKey)
-	require.NoError(t, err)
-	result = myValidator(context.Background(), "", &pubsub.Message{
-		Message: &pubsub_pb.Message{
-			Data: msgData,
-		},
-	})
+	myValidator = signedTopicBuilder(NewFakeTimesource(now5m1sInFuture), &prvKey.PublicKey)
+	result = myValidator(context.Background(), msg, protectedPubSubTopic)
 	require.False(t, result)
 }

waku/v2/protocol/relay/waku_relay.go

@@ -49,6 +49,10 @@ type WakuRelay struct {
 
 	minPeersToPublish int
 
+	topicValidatorMutex    sync.RWMutex
+	topicValidators        map[string][]validatorFn
+	defaultTopicValidators []validatorFn
+
 	// TODO: convert to concurrent maps
 	topicsMutex     sync.Mutex
 	wakuRelayTopics map[string]*pubsub.Topic
@@ -83,6 +87,7 @@ func NewWakuRelay(bcaster Broadcaster, minPeersToPublish int, timesource timesou
 	w.timesource = timesource
 	w.wakuRelayTopics = make(map[string]*pubsub.Topic)
 	w.relaySubs = make(map[string]*pubsub.Subscription)
+	w.topicValidators = make(map[string][]validatorFn)
 	w.bcaster = bcaster
 	w.minPeersToPublish = minPeersToPublish
 	w.CommonService = waku_proto.NewCommonService()
@@ -177,12 +182,6 @@ func NewWakuRelay(bcaster Broadcaster, minPeersToPublish int, timesource timesou
 		pubsub.WithSeenMessagesTTL(2 * time.Minute),
 		pubsub.WithPeerScore(w.peerScoreParams, w.peerScoreThresholds),
 		pubsub.WithPeerScoreInspect(w.peerScoreInspector, 6*time.Second),
-		// TODO: to improve - setup default validator only if no default validator has been set.
-		pubsub.WithDefaultValidator(func(ctx context.Context, peerID peer.ID, message *pubsub.Message) bool {
-			msg := new(pb.WakuMessage)
-			err := proto.Unmarshal(message.Data, msg)
-			return err == nil
-		}),
 	}, opts...)
 
 	return w
@@ -270,6 +269,11 @@ func (w *WakuRelay) upsertTopic(topic string) (*pubsub.Topic, error) {
 
 	pubSubTopic, ok := w.wakuRelayTopics[topic]
 	if !ok { // Joins topic if node hasn't joined yet
+		err := w.pubsub.RegisterTopicValidator(topic, w.topicValidator(topic))
+		if err != nil {
+			return nil, err
+		}
+
 		newTopic, err := w.pubsub.Join(string(topic))
 		if err != nil {
 			return nil, err
@@ -419,6 +423,8 @@ func (w *WakuRelay) Unsubscribe(ctx context.Context, topic string) error {
 	}
 	delete(w.wakuRelayTopics, topic)
 
+	w.RemoveTopicValidator(topic)
+
 	err = w.emitters.EvtRelayUnsubscribed.Emit(EvtRelayUnsubscribed{topic})
 	if err != nil {
 		return err

waku/v2/protocol/relay/waku_relay_test.go

@@ -79,10 +79,6 @@ func TestGossipsubScore(t *testing.T) {
 	relay := make([]*WakuRelay, 5)
 	for i := 0; i < 5; i++ {
 		hosts[i], relay[i] = createRelayNode(t)
-		if i == 0 {
-			// This is a hack to remove the default validator from the list of default options
-			relay[i].opts = relay[i].opts[:len(relay[i].opts)-1]
-		}
 		err := relay[i].Start(context.Background())
 		require.NoError(t, err)
 	}
@@ -119,6 +115,11 @@ func TestGossipsubScore(t *testing.T) {
 	// We obtain the go-libp2p topic directly because we normally can't publish anything other than WakuMessages
 	pubsubTopic, err := relay[0].upsertTopic(testTopic)
 	require.NoError(t, err)
+
+	// Removing validator from relayer0 to allow it to send invalid messages
+	err = relay[0].pubsub.UnregisterTopicValidator(testTopic)
+	require.NoError(t, err)
+
 	for i := 0; i < 50; i++ {
 		buf := make([]byte, 1000)
 		_, err := rand.Read(buf)

waku/v2/protocol/rln/common.go

@@ -26,7 +26,7 @@ const acceptableRootWindowSize = 5
 
 type RegistrationHandler = func(tx *types.Transaction)
 
-type SpamHandler = func(message *pb.WakuMessage) error
+type SpamHandler = func(msg *pb.WakuMessage, topic string) error
 
 func toRLNSignal(wakuMessage *pb.WakuMessage) []byte {
 	if wakuMessage == nil {