go-waku/waku/v2/protocol/relay/validators.go

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package relay
import (
"context"
"crypto/ecdsa"
"crypto/elliptic"
"encoding/hex"
"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"
"github.com/waku-org/go-waku/waku/v2/hash"
"github.com/waku-org/go-waku/waku/v2/protocol/pb"
"go.uber.org/zap"
proto "google.golang.org/protobuf/proto"
)
// Application level message hash
func MsgHash(pubSubTopic string, msg *pb.WakuMessage) []byte {
// TODO: Other fields?
return hash.SHA256([]byte(pubSubTopic), msg.Payload, []byte(msg.ContentTopic))
}
type validatorFn = func(ctx context.Context, peerID peer.ID, message *pubsub.Message) bool
func validatorFnBuilder(topic string, publicKey *ecdsa.PublicKey) validatorFn {
pubkBytes := crypto.FromECDSAPub(publicKey)
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
}
msgHash := MsgHash(topic, msg)
signature := msg.Meta
return secp256k1.VerifySignature(pubkBytes, msgHash, signature)
}
}
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))))
err := w.pubsub.RegisterTopicValidator(topic, validatorFnBuilder(topic, publicKey))
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if err != nil {
return err
}
if !w.IsSubscribed(topic) {
w.log.Warn("relay is not subscribed to signed topic", zap.String("topic", topic))
}
return nil
}
func SignMessage(privKey *ecdsa.PrivateKey, topic string, msg *pb.WakuMessage) error {
msgHash := MsgHash(topic, msg)
sign, err := secp256k1.Sign(msgHash, crypto.FromECDSA(privKey))
if err != nil {
return err
}
msg.Meta = sign[0:64] // Drop the V in R||S||V
return nil
}