multi: refactor SignMessage to specify hashing

funding/manager.go

@@ -327,7 +327,7 @@ type Config struct {
 	// TODO(roasbeef): should instead pass on this responsibility to a
 	// distinct sub-system?
 	SignMessage func(keyLoc keychain.KeyLocator,
-		msg []byte) (*btcec.Signature, error)
+		msg []byte, doubleHash bool) (*btcec.Signature, error)
 
 	// CurrentNodeAnnouncement should return the latest, fully signed node
 	// announcement from the backing Lightning Network node.
@@ -2911,7 +2911,7 @@ func (f *Manager) newChanAnnouncement(localPubKey,
 	if err != nil {
 		return nil, err
 	}
-	sig, err := f.cfg.SignMessage(f.cfg.IDKeyLoc, chanUpdateMsg)
+	sig, err := f.cfg.SignMessage(f.cfg.IDKeyLoc, chanUpdateMsg, true)
 	if err != nil {
 		return nil, errors.Errorf("unable to generate channel "+
 			"update announcement signature: %v", err)
@@ -2933,13 +2933,13 @@ func (f *Manager) newChanAnnouncement(localPubKey,
 	if err != nil {
 		return nil, err
 	}
-	nodeSig, err := f.cfg.SignMessage(f.cfg.IDKeyLoc, chanAnnMsg)
+	nodeSig, err := f.cfg.SignMessage(f.cfg.IDKeyLoc, chanAnnMsg, true)
 	if err != nil {
 		return nil, errors.Errorf("unable to generate node "+
 			"signature for channel announcement: %v", err)
 	}
 	bitcoinSig, err := f.cfg.SignMessage(
-		localFundingKey.KeyLocator, chanAnnMsg,
+		localFundingKey.KeyLocator, chanAnnMsg, true,
 	)
 	if err != nil {
 		return nil, errors.Errorf("unable to generate bitcoin "+

funding/manager_test.go

@@ -362,7 +362,7 @@ func createTestFundingManager(t *testing.T, privKey *btcec.PrivateKey,
 		Notifier:     chainNotifier,
 		FeeEstimator: estimator,
 		SignMessage: func(_ keychain.KeyLocator,
-			_ []byte) (*btcec.Signature, error) {
+			_ []byte, _ bool) (*btcec.Signature, error) {
 
 			return testSig, nil
 		},
@@ -510,7 +510,7 @@ func recreateAliceFundingManager(t *testing.T, alice *testNode) {
 		Notifier:     oldCfg.Notifier,
 		FeeEstimator: oldCfg.FeeEstimator,
 		SignMessage: func(_ keychain.KeyLocator,
-			_ []byte) (*btcec.Signature, error) {
+			_ []byte, _ bool) (*btcec.Signature, error) {
 
 			return testSig, nil
 		},

lntest/mock/signer.go

@@ -116,7 +116,7 @@ func (s *SingleSigner) ComputeInputScript(tx *wire.MsgTx,
 // SignMessage takes a public key and a message and only signs the message
 // with the stored private key if the public key matches the private key.
 func (s *SingleSigner) SignMessage(keyLoc keychain.KeyLocator,
-	msg []byte) (*btcec.Signature, error) {
+	msg []byte, doubleHash bool) (*btcec.Signature, error) {
 
 	mockKeyLoc := s.KeyLoc
 	if s.KeyLoc.IsEmpty() {
@@ -127,7 +127,12 @@ func (s *SingleSigner) SignMessage(keyLoc keychain.KeyLocator,
 		return nil, fmt.Errorf("unknown public key")
 	}
 
-	digest := chainhash.DoubleHashB(msg)
+	var digest []byte
+	if doubleHash {
+		digest = chainhash.DoubleHashB(msg)
+	} else {
+		digest = chainhash.HashB(msg)
+	}
 	sign, err := s.Privkey.Sign(digest)
 	if err != nil {
 		return nil, fmt.Errorf("can't sign the message: %v", err)

lnwallet/btcwallet/signer.go

@@ -267,7 +267,7 @@ var _ input.Signer = (*BtcWallet)(nil)
 //
 // NOTE: This is a part of the MessageSigner interface.
 func (b *BtcWallet) SignMessage(keyLoc keychain.KeyLocator,
-	msg []byte) (*btcec.Signature, error) {
+	msg []byte, doubleHash bool) (*btcec.Signature, error) {
 
 	// First attempt to fetch the private key which corresponds to the
 	// specified public key.
@@ -279,7 +279,12 @@ func (b *BtcWallet) SignMessage(keyLoc keychain.KeyLocator,
 	}
 
 	// Double hash and sign the data.
-	msgDigest := chainhash.DoubleHashB(msg)
+	var msgDigest []byte
+	if doubleHash {
+		msgDigest = chainhash.DoubleHashB(msg)
+	} else {
+		msgDigest = chainhash.HashB(msg)
+	}
 	sign, err := privKey.Sign(msgDigest)
 	if err != nil {
 		return nil, errors.Errorf("unable sign the message: %v", err)

lnwallet/interface.go

@@ -442,9 +442,9 @@ type MessageSigner interface {
 	// SignMessage attempts to sign a target message with the private key
 	// described in the key locator. If the target private key is unable to
 	// be found, then an error will be returned. The actual digest signed is
-	// the double SHA-256 of the passed message.
-	SignMessage(keyLoc keychain.KeyLocator, msg []byte) (*btcec.Signature,
-		error)
+	// the single or double SHA-256 of the passed message.
+	SignMessage(keyLoc keychain.KeyLocator, msg []byte,
+		doubleHash bool) (*btcec.Signature, error)
 }
 
 // WalletDriver represents a "driver" for a particular concrete

netann/channel_update_test.go

@@ -18,7 +18,7 @@ type mockSigner struct {
 }
 
 func (m *mockSigner) SignMessage(_ keychain.KeyLocator,
-	_ []byte) (*btcec.Signature, error) {
+	_ []byte, _ bool) (*btcec.Signature, error) {
 
 	if m.err != nil {
 		return nil, m.err

netann/node_signer.go

@@ -26,7 +26,7 @@ func NewNodeSigner(keySigner keychain.SingleKeyMessageSigner) *NodeSigner {
 // resident node's private key described in the key locator. If the target key
 // locator is _not_ the node's private key, then an error will be returned.
 func (n *NodeSigner) SignMessage(keyLoc keychain.KeyLocator,
-	msg []byte) (*btcec.Signature, error) {
+	msg []byte, doubleHash bool) (*btcec.Signature, error) {
 
 	// If this isn't our identity public key, then we'll exit early with an
 	// error as we can't sign with this key.
@@ -35,7 +35,7 @@ func (n *NodeSigner) SignMessage(keyLoc keychain.KeyLocator,
 	}
 
 	// Otherwise, we'll sign the double-sha256 of the target message.
-	sig, err := n.keySigner.SignMessage(msg, true)
+	sig, err := n.keySigner.SignMessage(msg, doubleHash)
 	if err != nil {
 		return nil, fmt.Errorf("can't sign the message: %v", err)
 	}

netann/sign.go

@@ -33,5 +33,5 @@ func SignAnnouncement(signer lnwallet.MessageSigner, keyLoc keychain.KeyLocator,
 		return nil, fmt.Errorf("unable to get data to sign: %v", err)
 	}
 
-	return signer.SignMessage(keyLoc, data)
+	return signer.SignMessage(keyLoc, data, true)
 }