multi: use prev output fetcher where possible

contractcourt/breacharbiter.go

@@ -1096,11 +1096,15 @@ func (bo *breachedOutput) SignDesc() *input.SignDescriptor {
 // sign descriptor. The method then returns the witness computed by invoking
 // this function on the first and subsequent calls.
 func (bo *breachedOutput) CraftInputScript(signer input.Signer, txn *wire.MsgTx,
-	hashCache *txscript.TxSigHashes, txinIdx int) (*input.Script, error) {
+	hashCache *txscript.TxSigHashes,
+	prevOutputFetcher txscript.PrevOutputFetcher,
+	txinIdx int) (*input.Script, error) {
 
 	// First, we ensure that the witness generation function has been
 	// initialized for this breached output.
-	bo.witnessFunc = bo.witnessType.WitnessGenerator(signer, bo.SignDesc())
+	signDesc := bo.SignDesc()
+	signDesc.PrevOutputFetcher = prevOutputFetcher
+	bo.witnessFunc = bo.witnessType.WitnessGenerator(signer, signDesc)
 
 	// Now that we have ensured that the witness generation function has
 	// been initialized, we can proceed to execute it and generate the
@@ -1397,8 +1401,8 @@ func (b *BreachArbiter) sweepSpendableOutputsTxn(txWeight int64,
 
 	// Compute the total amount contained in the inputs.
 	var totalAmt btcutil.Amount
-	for _, input := range inputs {
+	for _, inp := range inputs {
-		totalAmt += btcutil.Amount(input.SignDesc().Output.Value)
+		totalAmt += btcutil.Amount(inp.SignDesc().Output.Value)
 	}
 
 	// We'll actually attempt to target inclusion within the next two
@@ -1424,10 +1428,10 @@ func (b *BreachArbiter) sweepSpendableOutputsTxn(txWeight int64,
 
 	// Next, we add all of the spendable outputs as inputs to the
 	// transaction.
-	for _, input := range inputs {
+	for _, inp := range inputs {
 		txn.AddTxIn(&wire.TxIn{
-			PreviousOutPoint: *input.OutPoint(),
+			PreviousOutPoint: *inp.OutPoint(),
-			Sequence:         input.BlocksToMaturity(),
+			Sequence:         inp.BlocksToMaturity(),
 		})
 	}
 
@@ -1440,7 +1444,11 @@ func (b *BreachArbiter) sweepSpendableOutputsTxn(txWeight int64,
 
 	// Create a sighash cache to improve the performance of hashing and
 	// signing SigHashAll inputs.
-	hashCache := input.NewTxSigHashesV0Only(txn)
+	prevOutputFetcher, err := input.MultiPrevOutFetcher(inputs)
+	if err != nil {
+		return nil, err
+	}
+	hashCache := txscript.NewTxSigHashes(txn, prevOutputFetcher)
 
 	// Create a closure that encapsulates the process of initializing a
 	// particular output's witness generation function, computing the
@@ -1452,7 +1460,7 @@ func (b *BreachArbiter) sweepSpendableOutputsTxn(txWeight int64,
 		// transaction using the SpendableOutput's witness generation
 		// function.
 		inputScript, err := so.CraftInputScript(
-			b.cfg.Signer, txn, hashCache, idx,
+			b.cfg.Signer, txn, hashCache, prevOutputFetcher, idx,
 		)
 		if err != nil {
 			return err
@@ -1467,8 +1475,8 @@ func (b *BreachArbiter) sweepSpendableOutputsTxn(txWeight int64,
 
 	// Finally, generate a witness for each output and attach it to the
 	// transaction.
-	for i, input := range inputs {
+	for i, inp := range inputs {
-		if err := addWitness(i, input); err != nil {
+		if err := addWitness(i, inp); err != nil {
 			return nil, err
 		}
 	}
@@ -1648,7 +1656,7 @@ func (ret *retributionInfo) Encode(w io.Writer) error {
 	return nil
 }
 
-// Dencode deserializes a retribution from the passed byte stream.
+// Decode deserializes a retribution from the passed byte stream.
 func (ret *retributionInfo) Decode(r io.Reader) error {
 	var scratch [32]byte
 

contractcourt/breacharbiter_test.go

@@ -1386,8 +1386,11 @@ func getSpendTransactions(signer input.Signer, chanPoint *wire.OutPoint,
 		case input.HtlcAcceptedRevoke:
 			fallthrough
 		case input.HtlcOfferedRevoke:
+			cannedFetcher := txscript.NewCannedPrevOutputFetcher(
+				nil, 0,
+			)
 			inputScript, err := inp.CraftInputScript(
-				signer, htlcSweep, hashCache, 0,
+				signer, htlcSweep, hashCache, cannedFetcher, 0,
 			)
 			if err != nil {
 				return nil, err

input/input.go

@@ -42,6 +42,7 @@ type Input interface {
 	// also nested p2sh outputs.
 	CraftInputScript(signer Signer, txn *wire.MsgTx,
 		hashCache *txscript.TxSigHashes,
+		prevOutputFetcher txscript.PrevOutputFetcher,
 		txinIdx int) (*Script, error)
 
 	// BlocksToMaturity returns the relative timelock, as a number of
@@ -221,9 +222,13 @@ func NewCsvInputWithCltv(outpoint *wire.OutPoint, witnessType WitnessType,
 // txIndex within the passed transaction. The input scripts generated by this
 // method support spending p2wkh, p2wsh, and also nested p2sh outputs.
 func (bi *BaseInput) CraftInputScript(signer Signer, txn *wire.MsgTx,
-	hashCache *txscript.TxSigHashes, txinIdx int) (*Script, error) {
+	hashCache *txscript.TxSigHashes,
+	prevOutputFetcher txscript.PrevOutputFetcher, txinIdx int) (*Script,
+	error) {
 
-	witnessFunc := bi.witnessType.WitnessGenerator(signer, bi.SignDesc())
+	signDesc := bi.SignDesc()
+	signDesc.PrevOutputFetcher = prevOutputFetcher
+	witnessFunc := bi.witnessType.WitnessGenerator(signer, signDesc)
 
 	return witnessFunc(txn, hashCache, txinIdx)
 }
@@ -260,11 +265,14 @@ func MakeHtlcSucceedInput(outpoint *wire.OutPoint,
 // txIndex within the passed transaction. The input scripts generated by this
 // method support spending p2wkh, p2wsh, and also nested p2sh outputs.
 func (h *HtlcSucceedInput) CraftInputScript(signer Signer, txn *wire.MsgTx,
-	hashCache *txscript.TxSigHashes, txinIdx int) (*Script, error) {
+	hashCache *txscript.TxSigHashes,
+	prevOutputFetcher txscript.PrevOutputFetcher, txinIdx int) (*Script,
+	error) {
 
 	desc := h.signDesc
 	desc.SigHashes = hashCache
 	desc.InputIndex = txinIdx
+	desc.PrevOutputFetcher = prevOutputFetcher
 
 	witness, err := SenderHtlcSpendRedeem(
 		signer, &desc, txn, h.preimage,
@@ -291,7 +299,9 @@ type HtlcSecondLevelAnchorInput struct {
 	// createWitness creates a witness allowing the passed transaction to
 	// spend the input.
 	createWitness func(signer Signer, txn *wire.MsgTx,
-		hashCache *txscript.TxSigHashes, txinIdx int) (wire.TxWitness, error)
+		hashCache *txscript.TxSigHashes,
+		prevOutputFetcher txscript.PrevOutputFetcher,
+		txinIdx int) (wire.TxWitness, error)
 }
 
 // RequiredTxOut returns the tx out needed to be present on the sweep tx for
@@ -313,9 +323,12 @@ func (i *HtlcSecondLevelAnchorInput) RequiredLockTime() (uint32, bool) {
 // method support spending p2wkh, p2wsh, and also nested p2sh outputs.
 func (i *HtlcSecondLevelAnchorInput) CraftInputScript(signer Signer,
 	txn *wire.MsgTx, hashCache *txscript.TxSigHashes,
-	txinIdx int) (*Script, error) {
+	prevOutputFetcher txscript.PrevOutputFetcher, txinIdx int) (*Script,
+	error) {
 
-	witness, err := i.createWitness(signer, txn, hashCache, txinIdx)
+	witness, err := i.createWitness(
+		signer, txn, hashCache, prevOutputFetcher, txinIdx,
+	)
 	if err != nil {
 		return nil, err
 	}
@@ -335,11 +348,13 @@ func MakeHtlcSecondLevelTimeoutAnchorInput(signedTx *wire.MsgTx,
 	// 2nd timeout transaction.
 	createWitness := func(signer Signer, txn *wire.MsgTx,
 		hashCache *txscript.TxSigHashes,
+		prevOutputFetcher txscript.PrevOutputFetcher,
 		txinIdx int) (wire.TxWitness, error) {
 
 		desc := signDetails.SignDesc
-		desc.SigHashes = NewTxSigHashesV0Only(txn)
+		desc.SigHashes = txscript.NewTxSigHashes(txn, prevOutputFetcher)
 		desc.InputIndex = txinIdx
+		desc.PrevOutputFetcher = prevOutputFetcher
 
 		return SenderHtlcSpendTimeout(
 			signDetails.PeerSig, signDetails.SigHashType, signer,
@@ -373,11 +388,13 @@ func MakeHtlcSecondLevelSuccessAnchorInput(signedTx *wire.MsgTx,
 	// success transaction.
 	createWitness := func(signer Signer, txn *wire.MsgTx,
 		hashCache *txscript.TxSigHashes,
+		prevOutputFetcher txscript.PrevOutputFetcher,
 		txinIdx int) (wire.TxWitness, error) {
 
 		desc := signDetails.SignDesc
 		desc.SigHashes = hashCache
 		desc.InputIndex = txinIdx
+		desc.PrevOutputFetcher = prevOutputFetcher
 
 		return ReceiverHtlcSpendRedeem(
 			signDetails.PeerSig, signDetails.SigHashType,

input/signdescriptor.go

@@ -74,6 +74,11 @@ type SignDescriptor struct {
 	// generating the final sighash for signing.
 	SigHashes *txscript.TxSigHashes
 
+	// PrevOutputFetcher is an interface that can return the output
+	// information on all UTXOs that are being spent in this transaction.
+	// This MUST be set when spending Taproot outputs.
+	PrevOutputFetcher txscript.PrevOutputFetcher
+
 	// InputIndex is the target input within the transaction that should be
 	// signed.
 	InputIndex int

input/taproot.go

@@ -1,6 +1,8 @@
 package input
 
 import (
+	"fmt"
+
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 )
@@ -18,3 +20,25 @@ func NewTxSigHashesV0Only(tx *wire.MsgTx) *txscript.TxSigHashes {
 	nilFetcher := txscript.NewCannedPrevOutputFetcher(nil, 0)
 	return txscript.NewTxSigHashes(tx, nilFetcher)
 }
+
+// MultiPrevOutFetcher returns a txscript.MultiPrevOutFetcher for the given set
+// of inputs.
+func MultiPrevOutFetcher(inputs []Input) (*txscript.MultiPrevOutFetcher, error) {
+	fetcher := txscript.NewMultiPrevOutFetcher(nil)
+	for _, inp := range inputs {
+		op := inp.OutPoint()
+		desc := inp.SignDesc()
+
+		if op == nil {
+			return nil, fmt.Errorf("missing input outpoint")
+		}
+
+		if desc == nil || desc.Output == nil {
+			return nil, fmt.Errorf("missing input utxo information")
+		}
+
+		fetcher.AddPrevOut(*op, desc.Output)
+	}
+
+	return fetcher, nil
+}

lnwallet/btcwallet/psbt.go

@@ -9,6 +9,7 @@ import (
 	"github.com/btcsuite/btcd/btcutil/psbt"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcwallet/waddrmgr"
+	"github.com/btcsuite/btcwallet/wallet"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwallet/chainfee"
@@ -107,7 +108,8 @@ func (b *BtcWallet) SignPsbt(packet *psbt.Packet) error {
 	// there are inputs that we don't know how to sign, we won't return any
 	// error. So it's possible we're not the final signer.
 	tx := packet.UnsignedTx
-	sigHashes := input.NewTxSigHashesV0Only(tx)
+	prevOutputFetcher := wallet.PsbtPrevOutputFetcher(packet)
+	sigHashes := txscript.NewTxSigHashes(tx, prevOutputFetcher)
 	for idx := range tx.TxIn {
 		in := packet.Inputs[idx]
 

lnwallet/chanfunding/wallet_assembler.go

@@ -107,9 +107,15 @@ func (f *FullIntent) CompileFundingTx(extraInputs []*wire.TxIn,
 
 	// Next, sign all inputs that are ours, collecting the signatures in
 	// order of the inputs.
+	prevOutFetcher := NewSegWitV0DualFundingPrevOutputFetcher(
+		f.coinSource, extraInputs,
+	)
 	signDesc := input.SignDescriptor{
-		HashType:  txscript.SigHashAll,
+		HashType: txscript.SigHashAll,
-		SigHashes: input.NewTxSigHashesV0Only(fundingTx),
+		SigHashes: txscript.NewTxSigHashes(
+			fundingTx, prevOutFetcher,
+		),
+		PrevOutputFetcher: prevOutFetcher,
 	}
 	for i, txIn := range fundingTx.TxIn {
 		// We can only sign this input if it's ours, so we'll ask the
@@ -374,3 +380,55 @@ func (w *WalletAssembler) FundingTxAvailable() {}
 // A compile-time assertion to ensure the WalletAssembler meets the
 // FundingTxAssembler interface.
 var _ FundingTxAssembler = (*WalletAssembler)(nil)
+
+// SegWitV0DualFundingPrevOutputFetcher is a txscript.PrevOutputFetcher that
+// knows about local and remote funding inputs.
+//
+// TODO(guggero): Support dual funding with p2tr inputs, currently only segwit
+// v0 inputs are supported.
+type SegWitV0DualFundingPrevOutputFetcher struct {
+	local  CoinSource
+	remote *txscript.MultiPrevOutFetcher
+}
+
+var _ txscript.PrevOutputFetcher = (*SegWitV0DualFundingPrevOutputFetcher)(nil)
+
+// NewSegWitV0DualFundingPrevOutputFetcher creates a new
+// txscript.PrevOutputFetcher from the given local and remote inputs.
+//
+// NOTE: Since the actual pkScript and amounts aren't passed in, this will just
+// make sure that nothing will panic when creating a SegWit v0 sighash. But this
+// code will NOT WORK for transactions that spend any Taproot inputs!
+func NewSegWitV0DualFundingPrevOutputFetcher(localSource CoinSource,
+	remoteInputs []*wire.TxIn) txscript.PrevOutputFetcher {
+
+	remote := txscript.NewMultiPrevOutFetcher(nil)
+	for _, inp := range remoteInputs {
+		// We add an empty output to prevent the sighash calculation
+		// from panicking. But this will always detect the inputs as
+		// SegWig v0!
+		remote.AddPrevOut(inp.PreviousOutPoint, &wire.TxOut{})
+	}
+	return &SegWitV0DualFundingPrevOutputFetcher{
+		local:  localSource,
+		remote: remote,
+	}
+}
+
+// FetchPrevOutput attempts to fetch the previous output referenced by the
+// passed outpoint.
+//
+// NOTE: This is a part of the txscript.PrevOutputFetcher interface.
+func (d *SegWitV0DualFundingPrevOutputFetcher) FetchPrevOutput(
+	op wire.OutPoint) *wire.TxOut {
+
+	// Try the local source first. This will return nil if our internal
+	// wallet doesn't know the outpoint.
+	coin, err := d.local.CoinFromOutPoint(op)
+	if err == nil && coin != nil {
+		return &coin.TxOut
+	}
+
+	// Fall back to the remote
+	return d.remote.FetchPrevOutput(op)
+}

lnwallet/rpcwallet/rpcwallet.go

@@ -133,9 +133,11 @@ func (r *RPCKeyRing) SendOutputs(outputs []*wire.TxOut,
 
 	// We know at this point that we only have inputs from our own wallet.
 	// So we can just compute the input script using the remote signer.
+	outputFetcher := lnwallet.NewWalletPrevOutputFetcher(r.WalletController)
 	signDesc := input.SignDescriptor{
-		HashType:  txscript.SigHashAll,
+		HashType:          txscript.SigHashAll,
-		SigHashes: input.NewTxSigHashesV0Only(tx),
+		SigHashes:         txscript.NewTxSigHashes(tx, outputFetcher),
+		PrevOutputFetcher: outputFetcher,
 	}
 	for i, txIn := range tx.TxIn {
 		// We can only sign this input if it's ours, so we'll ask the
@@ -579,6 +581,32 @@ func (r *RPCKeyRing) remoteSign(tx *wire.MsgTx, signDesc *input.SignDescriptor,
 		return nil, fmt.Errorf("error converting TX into PSBT: %v", err)
 	}
 
+	// We need to add witness information for all inputs! Otherwise, we'll
+	// have a problem when attempting to sign a taproot input!
+	for idx := range packet.Inputs {
+		// Skip the input we're signing for, that will get a special
+		// treatment later on.
+		if idx == signDesc.InputIndex {
+			continue
+		}
+
+		txIn := tx.TxIn[idx]
+		info, err := r.WalletController.FetchInputInfo(
+			&txIn.PreviousOutPoint,
+		)
+		if err != nil {
+			log.Warnf("No UTXO info found for index %d "+
+				"(prev_outpoint=%v), won't be able to sign "+
+				"for taproot output!", idx,
+				txIn.PreviousOutPoint)
+			continue
+		}
+		packet.Inputs[idx].WitnessUtxo = &wire.TxOut{
+			Value:    int64(info.Value),
+			PkScript: info.PkScript,
+		}
+	}
+
 	// Catch incorrect signing input index, just in case.
 	if signDesc.InputIndex < 0 || signDesc.InputIndex >= len(packet.Inputs) {
 		return nil, fmt.Errorf("invalid input index in sign descriptor")

lnwallet/wallet.go

@@ -2266,3 +2266,36 @@ func validateUpfrontShutdown(shutdown lnwire.DeliveryAddress,
 		return false
 	}
 }
+
+// WalletPrevOutputFetcher is a txscript.PrevOutputFetcher that can fetch
+// outputs from a given wallet controller.
+type WalletPrevOutputFetcher struct {
+	wc WalletController
+}
+
+// A compile time assertion that WalletPrevOutputFetcher implements the
+// txscript.PrevOutputFetcher interface.
+var _ txscript.PrevOutputFetcher = (*WalletPrevOutputFetcher)(nil)
+
+// NewWalletPrevOutputFetcher creates a new WalletPrevOutputFetcher that fetches
+// previous outputs from the given wallet controller.
+func NewWalletPrevOutputFetcher(wc WalletController) *WalletPrevOutputFetcher {
+	return &WalletPrevOutputFetcher{
+		wc: wc,
+	}
+}
+
+// FetchPrevOutput attempts to fetch the previous output referenced by the
+// passed outpoint. A nil value will be returned if the passed outpoint doesn't
+// exist.
+func (w *WalletPrevOutputFetcher) FetchPrevOutput(op wire.OutPoint) *wire.TxOut {
+	utxo, err := w.wc.FetchInputInfo(&op)
+	if err != nil {
+		return nil
+	}
+
+	return &wire.TxOut{
+		Value:    int64(utxo.Value),
+		PkScript: utxo.PkScript,
+	}
+}

sweep/sweeper_test.go

@@ -1623,7 +1623,9 @@ func (i *testInput) RequiredTxOut() *wire.TxOut {
 // encode the spending outpoint and the tx input index as part of the returned
 // witness.
 func (i *testInput) CraftInputScript(_ input.Signer, txn *wire.MsgTx,
-	hashCache *txscript.TxSigHashes, txinIdx int) (*input.Script, error) {
+	hashCache *txscript.TxSigHashes,
+	prevOutputFetcher txscript.PrevOutputFetcher,
+	txinIdx int) (*input.Script, error) {
 
 	// We'll encode the outpoint in the witness, so we can assert that the
 	// expected input was signed at the correct index.

sweep/txgenerator.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/btcsuite/btcd/blockchain"
 	"github.com/btcsuite/btcd/btcutil"
+	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwallet"
@@ -263,13 +264,18 @@ func createSweepTx(inputs []input.Input, outputs []*wire.TxOut,
 		return nil, err
 	}
 
-	hashCache := input.NewTxSigHashesV0Only(sweepTx)
+	prevInputFetcher, err := input.MultiPrevOutFetcher(inputs)
+	if err != nil {
+		return nil, fmt.Errorf("error creating prev input fetcher "+
+			"for hash cache: %v", err)
+	}
+	hashCache := txscript.NewTxSigHashes(sweepTx, prevInputFetcher)
 
 	// With all the inputs in place, use each output's unique input script
 	// function to generate the final witness required for spending.
 	addInputScript := func(idx int, tso input.Input) error {
 		inputScript, err := tso.CraftInputScript(
-			signer, sweepTx, hashCache, idx,
+			signer, sweepTx, hashCache, prevInputFetcher, idx,
 		)
 		if err != nil {
 			return err

watchtower/lookout/justice_descriptor.go

@@ -2,6 +2,7 @@ package lookout
 
 import (
 	"errors"
+	"fmt"
 
 	"github.com/btcsuite/btcd/blockchain"
 	"github.com/btcsuite/btcd/btcec/v2"
@@ -177,11 +178,11 @@ func (p *JusticeDescriptor) assembleJusticeTxn(txWeight int64,
 	// First, construct add the breached inputs to our justice transaction
 	// and compute the total amount that will be swept.
 	var totalAmt btcutil.Amount
-	for _, input := range inputs {
+	for _, inp := range inputs {
-		totalAmt += btcutil.Amount(input.txOut.Value)
+		totalAmt += btcutil.Amount(inp.txOut.Value)
 		justiceTxn.AddTxIn(&wire.TxIn{
-			PreviousOutPoint: input.outPoint,
+			PreviousOutPoint: inp.outPoint,
-			Sequence:         input.sequence,
+			Sequence:         inp.sequence,
 		})
 	}
 
@@ -217,20 +218,22 @@ func (p *JusticeDescriptor) assembleJusticeTxn(txWeight int64,
 	}
 
 	// Attach each of the provided witnesses to the transaction.
-	for _, input := range inputs {
+	prevOutFetcher, err := prevOutFetcher(inputs)
+	if err != nil {
+		return nil, fmt.Errorf("error creating previous output "+
+			"fetcher: %v", err)
+	}
+	for _, inp := range inputs {
 		// Lookup the input's new post-sort position.
-		i := inputIndex[input.outPoint]
+		i := inputIndex[inp.outPoint]
-		justiceTxn.TxIn[i].Witness = input.witness
+		justiceTxn.TxIn[i].Witness = inp.witness
 
 		// Validate the reconstructed witnesses to ensure they are valid
 		// for the breached inputs.
 		vm, err := txscript.NewEngine(
-			input.txOut.PkScript, justiceTxn, i,
+			inp.txOut.PkScript, justiceTxn, i,
 			txscript.StandardVerifyFlags,
-			nil, nil, input.txOut.Value,
+			nil, nil, inp.txOut.Value, prevOutFetcher,
-			txscript.NewCannedPrevOutputFetcher(
-				input.txOut.PkScript, input.txOut.Value,
-			),
 		)
 		if err != nil {
 			return nil, err
@@ -345,3 +348,20 @@ func buildWitness(witnessStack [][]byte, witnessScript []byte) [][]byte {
 
 	return witness
 }
+
+// prevOutFetcher returns a txscript.MultiPrevOutFetcher for the given set
+// of inputs.
+func prevOutFetcher(inputs []*breachedInput) (*txscript.MultiPrevOutFetcher,
+	error) {
+
+	fetcher := txscript.NewMultiPrevOutFetcher(nil)
+	for _, inp := range inputs {
+		if inp.txOut == nil {
+			return nil, fmt.Errorf("missing input utxo information")
+		}
+
+		fetcher.AddPrevOut(inp.outPoint, inp.txOut)
+	}
+
+	return fetcher, nil
+}

watchtower/wtclient/backup_task.go

@@ -7,6 +7,7 @@ import (
 	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/btcutil/txsort"
+	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/input"
@@ -262,10 +263,14 @@ func (t *backupTask) craftSessionPayload(
 	// information. This will either be contain both the to-local and
 	// to-remote outputs, or only be the to-local output.
 	inputs := t.inputs()
-	for prevOutPoint, input := range inputs {
+	prevOutputFetcher := txscript.NewMultiPrevOutFetcher(nil)
+	for prevOutPoint, inp := range inputs {
+		prevOutputFetcher.AddPrevOut(
+			prevOutPoint, inp.SignDesc().Output,
+		)
 		justiceTxn.AddTxIn(&wire.TxIn{
 			PreviousOutPoint: prevOutPoint,
-			Sequence:         input.BlocksToMaturity(),
+			Sequence:         inp.BlocksToMaturity(),
 		})
 	}
 
@@ -284,7 +289,7 @@ func (t *backupTask) craftSessionPayload(
 	}
 
 	// Construct a sighash cache to improve signing performance.
-	hashCache := input.NewTxSigHashesV0Only(justiceTxn)
+	hashCache := txscript.NewTxSigHashes(justiceTxn, prevOutputFetcher)
 
 	// Since the transaction inputs could have been reordered as a result of
 	// the BIP69 sort, create an index mapping each prevout to it's new
@@ -303,7 +308,7 @@ func (t *backupTask) craftSessionPayload(
 
 		// Construct the full witness required to spend this input.
 		inputScript, err := inp.CraftInputScript(
-			signer, justiceTxn, hashCache, i,
+			signer, justiceTxn, hashCache, prevOutputFetcher, i,
 		)
 		if err != nil {
 			return hint, nil, err