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lnwallet: update the btcwallet Signer interface due to new key derivation

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This commit is contained in:
Olaoluwa Osuntokun 2017-07-30 11:44:48 -07:00
parent c872d94606
commit 5dc0b407f3
No known key found for this signature in database
GPG Key ID: 9CC5B105D03521A2
1 changed files with 45 additions and 7 deletions
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52
lnwallet/btcwallet/signer.go
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@ -90,11 +90,36 @@ func (b *BtcWallet) fetchPrivKey(pub *btcec.PublicKey) (*btcec.PrivateKey, error
return b.wallet.PrivKeyForAddress(addr)
}
// maybeTweakPrivKey examines the single and double tweak parameters on the
// passed sign descriptor and may perform a mapping on the passed private key
// in order to utilize the tweaks, if populated.
func maybeTweakPrivKey(signDesc *lnwallet.SignDescriptor,
privKey *btcec.PrivateKey) (*btcec.PrivateKey, error) {
var retPriv *btcec.PrivateKey
switch {
case signDesc.SingleTweak != nil:
retPriv = lnwallet.TweakPrivKey(privKey,
signDesc.SingleTweak)
case signDesc.DoubleTweak != nil:
retPriv = lnwallet.DeriveRevocationPrivKey(privKey,
signDesc.DoubleTweak)
default:
retPriv = privKey
}
return retPriv, nil
}
// SignOutputRaw generates a signature for the passed transaction according to
// the data within the passed SignDescriptor.
//
// This is a part of the WalletController interface.
func (b *BtcWallet) SignOutputRaw(tx *wire.MsgTx, signDesc *lnwallet.SignDescriptor) ([]byte, error) {
func (b *BtcWallet) SignOutputRaw(tx *wire.MsgTx,
signDesc *lnwallet.SignDescriptor) ([]byte, error) {
witnessScript := signDesc.WitnessScript
// First attempt to fetch the private key which corresponds to the
@ -104,13 +129,16 @@ func (b *BtcWallet) SignOutputRaw(tx *wire.MsgTx, signDesc *lnwallet.SignDescrip
return nil, err
}
// If a tweak is specified, then we'll need to use this tweak to derive
// the final private key to be used for signing this output.
if signDesc.PrivateTweak != nil {
privKey = lnwallet.DeriveRevocationPrivKey(privKey,
signDesc.PrivateTweak)
// If a tweak (single or double) is specified, then we'll need to use
// this tweak to derive the final private key to be used for signing
// this output.
privKey, err = maybeTweakPrivKey(signDesc, privKey)
if err != nil {
return nil, err
}
// TODO(roasbeef): generate sighash midstate if not present?
amt := signDesc.Output.Value
sig, err := txscript.RawTxInWitnessSignature(tx, signDesc.SigHashes,
signDesc.InputIndex, amt, witnessScript, txscript.SigHashAll,
@ -147,9 +175,10 @@ func (b *BtcWallet) ComputeInputScript(tx *wire.MsgTx,
var witnessProgram []byte
inputScript := &lnwallet.InputScript{}
switch {
// If we're spending p2wkh output nested within a p2sh output, then
// we'll need to attach a sigScript in addition to witness data.
switch {
case pka.IsNestedWitness():
pubKey := privKey.PubKey()
pubKeyHash := btcutil.Hash160(pubKey.SerializeCompressed())
@ -176,6 +205,7 @@ func (b *BtcWallet) ComputeInputScript(tx *wire.MsgTx,
}
inputScript.ScriptSig = sigScript
// Otherwise, this is a regular p2wkh output, so we include the
// witness program itself as the subscript to generate the proper
// sighash digest. As part of the new sighash digest algorithm, the
@ -185,6 +215,14 @@ func (b *BtcWallet) ComputeInputScript(tx *wire.MsgTx,
witnessProgram = outputScript
}
// If a tweak (single or double) is specified, then we'll need to use
// this tweak to derive the final private key to be used for signing
// this output.
privKey, err = maybeTweakPrivKey(signDesc, privKey)
if err != nil {
return nil, err
}
// Generate a valid witness stack for the input.
// TODO(roasbeef): adhere to passed HashType
witnessScript, err := txscript.WitnessScript(tx, signDesc.SigHashes,