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https://github.com/muun/recovery.git
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Release v0.3.0
This commit is contained in:
Manu Herrera
278
vendor/github.com/muun/libwallet/incoming_swap.go
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vendored
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278
vendor/github.com/muun/libwallet/incoming_swap.go
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vendored
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@@ -0,0 +1,278 @@
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package libwallet
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import (
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"bytes"
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"crypto/sha256"
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"fmt"
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"github.com/btcsuite/btcd/chaincfg"
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"github.com/btcsuite/btcd/txscript"
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"github.com/btcsuite/btcd/wire"
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"github.com/btcsuite/btcutil"
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"github.com/lightningnetwork/lnd/lnwire"
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"github.com/muun/libwallet/hdpath"
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"github.com/muun/libwallet/sphinx"
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"github.com/pkg/errors"
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)
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type coinIncomingSwap struct {
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Network *chaincfg.Params
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MuunSignature []byte
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Sphinx []byte
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HtlcTx []byte
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PaymentHash256 []byte
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SwapServerPublicKey []byte
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ExpirationHeight int64
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VerifyOutputAmount bool // used only for fulfilling swaps through IncomingSwap
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}
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func (c *coinIncomingSwap) SignInput(index int, tx *wire.MsgTx, userKey *HDPrivateKey, muunKey *HDPublicKey) error {
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// Deserialize the HTLC transaction
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htlcTx := wire.MsgTx{}
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err := htlcTx.Deserialize(bytes.NewReader(c.HtlcTx))
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if err != nil {
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return fmt.Errorf("could not deserialize htlc tx: %w", err)
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}
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// Lookup invoice data matching this HTLC using the payment hash
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db, err := openDB()
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if err != nil {
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return err
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}
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defer db.Close()
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secrets, err := db.FindByPaymentHash(c.PaymentHash256)
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if err != nil {
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return fmt.Errorf("could not find invoice data for payment hash: %w", err)
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}
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// Recreate the HTLC script to verify it matches the transaction. For this
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// we must derive the keys used in the HTLC script
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htlcKeyPath := hdpath.MustParse(secrets.KeyPath).Child(htlcKeyChildIndex)
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// Derive first the private key, which we are going to use for signing later
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userPrivateKey, err := userKey.DeriveTo(htlcKeyPath.String())
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if err != nil {
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return err
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}
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userPublicKey := userPrivateKey.PublicKey()
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muunPublicKey, err := muunKey.DeriveTo(htlcKeyPath.String())
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if err != nil {
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return err
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}
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htlcScript, err := c.createHtlcScript(userPublicKey, muunPublicKey)
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if err != nil {
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return fmt.Errorf("could not create htlc script: %w", err)
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}
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// Try to find the script we just built inside the HTLC output scripts
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htlcOutputIndex, err := c.findHtlcOutputIndex(&htlcTx, htlcScript)
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if err != nil {
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return err
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}
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// Next, we must validate the sphinx data. We derive the client identity
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// key used by this invoice with the key path stored in the db.
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identityKeyPath := hdpath.MustParse(secrets.KeyPath).Child(identityKeyChildIndex)
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nodeHDKey, err := userKey.DeriveTo(identityKeyPath.String())
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if err != nil {
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return err
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}
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nodeKey, err := nodeHDKey.key.ECPrivKey()
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if err != nil {
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return err
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}
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txInput := tx.TxIn[index]
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if txInput.PreviousOutPoint.Hash != htlcTx.TxHash() {
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return fmt.Errorf("expected fulfillment tx input to point to htlc tx")
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}
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if txInput.PreviousOutPoint.Index != uint32(htlcOutputIndex) {
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return fmt.Errorf("expected fulfillment tx input to point to correct htlc output")
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}
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sigHashes := txscript.NewTxSigHashes(tx)
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muunSigKey, err := muunPublicKey.key.ECPubKey()
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if err != nil {
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return err
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}
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// Verify Muun signature
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htlcOutputAmount := htlcTx.TxOut[htlcOutputIndex].Value
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err = verifyTxWitnessSignature(
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tx,
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sigHashes,
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index,
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htlcOutputAmount,
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htlcScript,
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c.MuunSignature,
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muunSigKey,
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)
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if err != nil {
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return fmt.Errorf("could not verify Muun signature for htlc: %w", err)
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}
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var outputAmount lnwire.MilliSatoshi
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if c.VerifyOutputAmount {
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outputAmount = lnwire.MilliSatoshi(tx.TxOut[0].Value * 1000)
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}
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// Now check the information we have against the sphinx created by the payer
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if len(c.Sphinx) > 0 {
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err = sphinx.Validate(
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c.Sphinx,
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c.PaymentHash256,
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secrets.PaymentSecret,
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nodeKey,
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uint32(c.ExpirationHeight),
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outputAmount,
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c.Network,
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)
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if err != nil {
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return fmt.Errorf("could not verify sphinx blob: %w", err)
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}
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}
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// Sign the fulfillment tx
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sig, err := signNativeSegwitInput(
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index,
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tx,
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userPrivateKey,
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htlcScript,
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btcutil.Amount(htlcOutputAmount),
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)
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if err != nil {
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return fmt.Errorf("could not sign fulfillment tx: %w", err)
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}
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txInput.Witness = wire.TxWitness{
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secrets.Preimage,
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sig,
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c.MuunSignature,
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htlcScript,
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}
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return nil
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}
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func (c *coinIncomingSwap) FullySignInput(index int, tx *wire.MsgTx, userKey, muunKey *HDPrivateKey) error {
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// Lookup invoice data matching this HTLC using the payment hash
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db, err := openDB()
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if err != nil {
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return err
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}
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defer db.Close()
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secrets, err := db.FindByPaymentHash(c.PaymentHash256)
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if err != nil {
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return fmt.Errorf("could not find invoice data for payment hash: %w", err)
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}
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derivedMuunKey, err := muunKey.DeriveTo(secrets.KeyPath)
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if err != nil {
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return errors.Wrapf(err, "failed to derive muun key")
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}
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muunSignature, err := c.signature(index, tx, userKey.PublicKey(), derivedMuunKey.PublicKey(), derivedMuunKey)
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if err != nil {
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return err
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}
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c.MuunSignature = muunSignature
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return c.SignInput(index, tx, userKey, muunKey.PublicKey())
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}
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func (c *coinIncomingSwap) createHtlcScript(userPublicKey, muunPublicKey *HDPublicKey) ([]byte, error) {
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return createHtlcScript(
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userPublicKey.Raw(),
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muunPublicKey.Raw(),
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c.SwapServerPublicKey,
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c.ExpirationHeight,
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c.PaymentHash256,
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)
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}
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func (c *coinIncomingSwap) signature(index int, tx *wire.MsgTx, userKey *HDPublicKey, muunKey *HDPublicKey,
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signingKey *HDPrivateKey) ([]byte, error) {
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htlcTx := wire.MsgTx{}
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err := htlcTx.Deserialize(bytes.NewReader(c.HtlcTx))
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if err != nil {
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return nil, fmt.Errorf("could not deserialize htlc tx: %w", err)
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}
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htlcScript, err := c.createHtlcScript(userKey, muunKey)
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if err != nil {
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return nil, fmt.Errorf("could not create htlc script: %w", err)
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}
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htlcOutputIndex, err := c.findHtlcOutputIndex(&htlcTx, htlcScript)
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if err != nil {
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return nil, err
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}
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prevOutAmount := htlcTx.TxOut[htlcOutputIndex].Value
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sig, err := signNativeSegwitInput(
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index,
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tx,
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signingKey,
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htlcScript,
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btcutil.Amount(prevOutAmount),
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)
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if err != nil {
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return nil, fmt.Errorf("could not sign fulfillment tx: %w", err)
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}
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return sig, nil
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}
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func (c *coinIncomingSwap) findHtlcOutputIndex(htlcTx *wire.MsgTx, htlcScript []byte) (int, error) {
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witnessHash := sha256.Sum256(htlcScript)
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address, err := btcutil.NewAddressWitnessScriptHash(witnessHash[:], c.Network)
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if err != nil {
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return 0, fmt.Errorf("could not create htlc address: %w", err)
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}
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pkScript, err := txscript.PayToAddrScript(address)
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if err != nil {
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return 0, fmt.Errorf("could not create pk script: %w", err)
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}
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// Try to find the script we just built inside the HTLC output scripts
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for i, out := range htlcTx.TxOut {
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if bytes.Equal(pkScript, out.PkScript) {
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return i, nil
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}
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}
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return 0, errors.New("could not find valid htlc output in htlc tx")
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}
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func createHtlcScript(userPublicKey, muunPublicKey, swapServerPublicKey []byte, expiry int64, paymentHash []byte) ([]byte, error) {
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sb := txscript.NewScriptBuilder()
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sb.AddData(muunPublicKey)
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sb.AddOp(txscript.OP_CHECKSIG)
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sb.AddOp(txscript.OP_NOTIF)
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sb.AddOp(txscript.OP_DUP)
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sb.AddOp(txscript.OP_HASH160)
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sb.AddData(btcutil.Hash160(swapServerPublicKey))
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sb.AddOp(txscript.OP_EQUALVERIFY)
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sb.AddOp(txscript.OP_CHECKSIGVERIFY)
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sb.AddInt64(expiry)
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sb.AddOp(txscript.OP_CHECKLOCKTIMEVERIFY)
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sb.AddOp(txscript.OP_ELSE)
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sb.AddData(userPublicKey)
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sb.AddOp(txscript.OP_CHECKSIGVERIFY)
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sb.AddOp(txscript.OP_SIZE)
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sb.AddInt64(32)
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sb.AddOp(txscript.OP_EQUALVERIFY)
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sb.AddOp(txscript.OP_HASH160)
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sb.AddData(ripemd160(paymentHash))
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sb.AddOp(txscript.OP_EQUAL)
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sb.AddOp(txscript.OP_ENDIF)
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return sb.Script()
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}
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