lnd/input/size_test.go
Conner Fromknecht c1b9b272cd
input/size: assert witness size constants
This commit introduces a new test case that asserts all of the witness
size constants currently in the codebase. We also reintroduce the
AcceptedHtlcSuccessWitnessSize and OfferedHtlcTimeoutWitnessSize
constants that were recently removed for the sake of completeness.

In asserting the witnes sizes, there were three uncovered discrepancies:
 * OfferedHtlcSuccessWitnessSize overestimated by about 30% because it
   included an extra signature in the calculation.

 * ToLocalPenaltyWitnessSize was underestimated by one byte, because it
   was missing the length byte for the OP_TRUE. This has implications
   the watchtower protocol since the client and server are assumed to
   share the same weight estimates used for signing. This commit keeps
   the current behavior, with the intention of rolling out negotiation
   for which weight estimate to use for a given session.

 * AcceptedHtlcScriptSize was underestimated by one byte because it was
   missing a length byte for the value 32 pushed on the stack when
   asserting the preimage's length. This affects all AcceptedHtlc*
   witness sizes.
2020-04-10 15:34:27 -07:00

848 lines
18 KiB
Go

package input_test
import (
"math/big"
"testing"
"github.com/btcsuite/btcd/blockchain"
"github.com/btcsuite/btcd/btcec"
"github.com/btcsuite/btcd/chaincfg"
"github.com/btcsuite/btcd/txscript"
"github.com/btcsuite/btcd/wire"
"github.com/btcsuite/btcutil"
"github.com/lightningnetwork/lnd/input"
"github.com/lightningnetwork/lnd/keychain"
)
const (
testCSVDelay = (1 << 31) - 1
testCLTVExpiry = 500000000
// maxDERSignatureSize is the largest possible DER-encoded signature
// without the trailing sighash flag.
maxDERSignatureSize = 72
)
var (
testPubkeyBytes = make([]byte, 33)
testHash160 = make([]byte, 20)
testPreimage = make([]byte, 32)
// testPubkey is a pubkey used in script size calculation.
testPubkey = &btcec.PublicKey{
X: &big.Int{},
Y: &big.Int{},
}
testPrivkey, _ = btcec.PrivKeyFromBytes(btcec.S256(), make([]byte, 32))
testTx = wire.NewMsgTx(2)
)
// TestTxWeightEstimator tests that transaction weight estimates are calculated
// correctly by comparing against an actual (though invalid) transaction
// matching the template.
func TestTxWeightEstimator(t *testing.T) {
netParams := &chaincfg.MainNetParams
p2pkhAddr, err := btcutil.NewAddressPubKeyHash(
make([]byte, 20), netParams)
if err != nil {
t.Fatalf("Failed to generate address: %v", err)
}
p2pkhScript, err := txscript.PayToAddrScript(p2pkhAddr)
if err != nil {
t.Fatalf("Failed to generate scriptPubKey: %v", err)
}
p2wkhAddr, err := btcutil.NewAddressWitnessPubKeyHash(
make([]byte, 20), netParams)
if err != nil {
t.Fatalf("Failed to generate address: %v", err)
}
p2wkhScript, err := txscript.PayToAddrScript(p2wkhAddr)
if err != nil {
t.Fatalf("Failed to generate scriptPubKey: %v", err)
}
p2wshAddr, err := btcutil.NewAddressWitnessScriptHash(
make([]byte, 32), netParams)
if err != nil {
t.Fatalf("Failed to generate address: %v", err)
}
p2wshScript, err := txscript.PayToAddrScript(p2wshAddr)
if err != nil {
t.Fatalf("Failed to generate scriptPubKey: %v", err)
}
p2shAddr, err := btcutil.NewAddressScriptHash([]byte{0}, netParams)
if err != nil {
t.Fatalf("Failed to generate address: %v", err)
}
p2shScript, err := txscript.PayToAddrScript(p2shAddr)
if err != nil {
t.Fatalf("Failed to generate scriptPubKey: %v", err)
}
testCases := []struct {
numP2PKHInputs int
numP2WKHInputs int
numP2WSHInputs int
numNestedP2WKHInputs int
numNestedP2WSHInputs int
numP2PKHOutputs int
numP2WKHOutputs int
numP2WSHOutputs int
numP2SHOutputs int
}{
// Assert base txn size.
{},
// Assert single input/output sizes.
{
numP2PKHInputs: 1,
},
{
numP2WKHInputs: 1,
},
{
numP2WSHInputs: 1,
},
{
numNestedP2WKHInputs: 1,
},
{
numNestedP2WSHInputs: 1,
},
{
numP2WKHOutputs: 1,
},
{
numP2PKHOutputs: 1,
},
{
numP2WSHOutputs: 1,
},
{
numP2SHOutputs: 1,
},
// Assert each input/output increments input/output counts.
{
numP2PKHInputs: 253,
},
{
numP2WKHInputs: 253,
},
{
numP2WSHInputs: 253,
},
{
numNestedP2WKHInputs: 253,
},
{
numNestedP2WSHInputs: 253,
},
{
numP2WKHOutputs: 253,
},
{
numP2PKHOutputs: 253,
},
{
numP2WSHOutputs: 253,
},
{
numP2SHOutputs: 253,
},
// Assert basic combinations of inputs and outputs.
{
numP2PKHInputs: 1,
numP2PKHOutputs: 2,
},
{
numP2PKHInputs: 1,
numP2WKHInputs: 1,
numP2WKHOutputs: 1,
numP2WSHOutputs: 1,
},
{
numP2WKHInputs: 1,
numP2WKHOutputs: 1,
numP2WSHOutputs: 1,
},
{
numP2WKHInputs: 2,
numP2WKHOutputs: 1,
numP2WSHOutputs: 1,
},
{
numP2WSHInputs: 1,
numP2WKHOutputs: 1,
},
{
numP2PKHInputs: 1,
numP2SHOutputs: 1,
},
{
numNestedP2WKHInputs: 1,
numP2WKHOutputs: 1,
},
{
numNestedP2WSHInputs: 1,
numP2WKHOutputs: 1,
},
// Assert disparate input/output types increment total
// input/output counts.
{
numP2PKHInputs: 50,
numP2WKHInputs: 50,
numP2WSHInputs: 51,
numNestedP2WKHInputs: 51,
numNestedP2WSHInputs: 51,
numP2WKHOutputs: 1,
},
{
numP2WKHInputs: 1,
numP2WKHOutputs: 63,
numP2PKHOutputs: 63,
numP2WSHOutputs: 63,
numP2SHOutputs: 64,
},
{
numP2PKHInputs: 50,
numP2WKHInputs: 50,
numP2WSHInputs: 51,
numNestedP2WKHInputs: 51,
numNestedP2WSHInputs: 51,
numP2WKHOutputs: 63,
numP2PKHOutputs: 63,
numP2WSHOutputs: 63,
numP2SHOutputs: 64,
},
}
for i, test := range testCases {
var weightEstimate input.TxWeightEstimator
tx := wire.NewMsgTx(1)
for j := 0; j < test.numP2PKHInputs; j++ {
weightEstimate.AddP2PKHInput()
signature := make([]byte, maxDERSignatureSize+1)
compressedPubKey := make([]byte, 33)
scriptSig, err := txscript.NewScriptBuilder().AddData(signature).
AddData(compressedPubKey).Script()
if err != nil {
t.Fatalf("Failed to generate scriptSig: %v", err)
}
tx.AddTxIn(&wire.TxIn{SignatureScript: scriptSig})
}
for j := 0; j < test.numP2WKHInputs; j++ {
weightEstimate.AddP2WKHInput()
signature := make([]byte, maxDERSignatureSize+1)
compressedPubKey := make([]byte, 33)
witness := wire.TxWitness{signature, compressedPubKey}
tx.AddTxIn(&wire.TxIn{Witness: witness})
}
for j := 0; j < test.numP2WSHInputs; j++ {
weightEstimate.AddWitnessInput(42)
witnessScript := make([]byte, 40)
witness := wire.TxWitness{witnessScript}
tx.AddTxIn(&wire.TxIn{Witness: witness})
}
for j := 0; j < test.numNestedP2WKHInputs; j++ {
weightEstimate.AddNestedP2WKHInput()
signature := make([]byte, maxDERSignatureSize+1)
compressedPubKey := make([]byte, 33)
witness := wire.TxWitness{signature, compressedPubKey}
scriptSig, err := txscript.NewScriptBuilder().AddData(p2wkhScript).
Script()
if err != nil {
t.Fatalf("Failed to generate scriptSig: %v", err)
}
tx.AddTxIn(&wire.TxIn{SignatureScript: scriptSig, Witness: witness})
}
for j := 0; j < test.numNestedP2WSHInputs; j++ {
weightEstimate.AddNestedP2WSHInput(42)
witnessScript := make([]byte, 40)
witness := wire.TxWitness{witnessScript}
scriptSig, err := txscript.NewScriptBuilder().AddData(p2wshScript).
Script()
if err != nil {
t.Fatalf("Failed to generate scriptSig: %v", err)
}
tx.AddTxIn(&wire.TxIn{SignatureScript: scriptSig, Witness: witness})
}
for j := 0; j < test.numP2PKHOutputs; j++ {
weightEstimate.AddP2PKHOutput()
tx.AddTxOut(&wire.TxOut{PkScript: p2pkhScript})
}
for j := 0; j < test.numP2WKHOutputs; j++ {
weightEstimate.AddP2WKHOutput()
tx.AddTxOut(&wire.TxOut{PkScript: p2wkhScript})
}
for j := 0; j < test.numP2WSHOutputs; j++ {
weightEstimate.AddP2WSHOutput()
tx.AddTxOut(&wire.TxOut{PkScript: p2wshScript})
}
for j := 0; j < test.numP2SHOutputs; j++ {
weightEstimate.AddP2SHOutput()
tx.AddTxOut(&wire.TxOut{PkScript: p2shScript})
}
expectedWeight := blockchain.GetTransactionWeight(btcutil.NewTx(tx))
if weightEstimate.Weight() != int(expectedWeight) {
t.Errorf("Case %d: Got wrong weight: expected %d, got %d",
i, expectedWeight, weightEstimate.Weight())
}
}
}
type maxDERSignature struct{}
func (s *maxDERSignature) Serialize() []byte {
// Always return worst-case signature length, excluding the one byte
// sighash flag.
return make([]byte, maxDERSignatureSize)
}
func (s *maxDERSignature) Verify(_ []byte, _ *btcec.PublicKey) bool {
return true
}
// dummySigner is a fake signer used for size (upper bound) calculations.
type dummySigner struct {
input.Signer
}
// SignOutputRaw generates a signature for the passed transaction according to
// the data within the passed SignDescriptor.
func (s *dummySigner) SignOutputRaw(tx *wire.MsgTx,
signDesc *input.SignDescriptor) (input.Signature, error) {
return &maxDERSignature{}, nil
}
type witnessSizeTest struct {
name string
expSize int
genWitness func(t *testing.T) wire.TxWitness
}
var witnessSizeTests = []witnessSizeTest{
{
name: "funding",
expSize: input.MultiSigWitnessSize,
genWitness: func(t *testing.T) wire.TxWitness {
witnessScript, _, err := input.GenFundingPkScript(
testPubkeyBytes, testPubkeyBytes, 1,
)
if err != nil {
t.Fatal(err)
}
return input.SpendMultiSig(
witnessScript,
testPubkeyBytes, &maxDERSignature{},
testPubkeyBytes, &maxDERSignature{},
)
},
},
{
name: "to local timeout",
expSize: input.ToLocalTimeoutWitnessSize,
genWitness: func(t *testing.T) wire.TxWitness {
witnessScript, err := input.CommitScriptToSelf(
testCSVDelay, testPubkey, testPubkey,
)
if err != nil {
t.Fatal(err)
}
signDesc := &input.SignDescriptor{
WitnessScript: witnessScript,
}
witness, err := input.CommitSpendTimeout(
&dummySigner{}, signDesc, testTx,
)
if err != nil {
t.Fatal(err)
}
return witness
},
},
{
name: "to local revoke",
expSize: input.ToLocalPenaltyWitnessSize,
genWitness: func(t *testing.T) wire.TxWitness {
witnessScript, err := input.CommitScriptToSelf(
testCSVDelay, testPubkey, testPubkey,
)
if err != nil {
t.Fatal(err)
}
signDesc := &input.SignDescriptor{
WitnessScript: witnessScript,
}
witness, err := input.CommitSpendRevoke(
&dummySigner{}, signDesc, testTx,
)
if err != nil {
t.Fatal(err)
}
return witness
},
},
{
name: "to remote confirmed",
expSize: input.ToRemoteConfirmedWitnessSize,
genWitness: func(t *testing.T) wire.TxWitness {
witScript, err := input.CommitScriptToRemoteConfirmed(
testPubkey,
)
if err != nil {
t.Fatal(err)
}
signDesc := &input.SignDescriptor{
WitnessScript: witScript,
KeyDesc: keychain.KeyDescriptor{
PubKey: testPubkey,
},
}
witness, err := input.CommitSpendToRemoteConfirmed(
&dummySigner{}, signDesc, testTx,
)
if err != nil {
t.Fatal(err)
}
return witness
},
},
{
name: "anchor",
expSize: input.AnchorWitnessSize,
genWitness: func(t *testing.T) wire.TxWitness {
witScript, err := input.CommitScriptAnchor(
testPubkey,
)
if err != nil {
t.Fatal(err)
}
signDesc := &input.SignDescriptor{
WitnessScript: witScript,
KeyDesc: keychain.KeyDescriptor{
PubKey: testPubkey,
},
}
witness, err := input.CommitSpendAnchor(
&dummySigner{}, signDesc, testTx,
)
if err != nil {
t.Fatal(err)
}
return witness
},
},
{
name: "anchor anyone",
expSize: 43,
genWitness: func(t *testing.T) wire.TxWitness {
witScript, err := input.CommitScriptAnchor(
testPubkey,
)
if err != nil {
t.Fatal(err)
}
witness, _ := input.CommitSpendAnchorAnyone(witScript)
return witness
},
},
{
name: "offered htlc revoke",
expSize: input.OfferedHtlcPenaltyWitnessSize - 3,
genWitness: func(t *testing.T) wire.TxWitness {
witScript, err := input.SenderHTLCScript(
testPubkey, testPubkey, testPubkey,
testHash160, false,
)
if err != nil {
t.Fatal(err)
}
signDesc := &input.SignDescriptor{
WitnessScript: witScript,
KeyDesc: keychain.KeyDescriptor{
PubKey: testPubkey,
},
DoubleTweak: testPrivkey,
}
witness, err := input.SenderHtlcSpendRevoke(
&dummySigner{}, signDesc, testTx,
)
if err != nil {
t.Fatal(err)
}
return witness
},
},
{
name: "offered htlc revoke confirmed",
expSize: input.OfferedHtlcPenaltyWitnessSize,
genWitness: func(t *testing.T) wire.TxWitness {
hash := make([]byte, 20)
witScript, err := input.SenderHTLCScript(
testPubkey, testPubkey, testPubkey,
hash, true,
)
if err != nil {
t.Fatal(err)
}
signDesc := &input.SignDescriptor{
WitnessScript: witScript,
KeyDesc: keychain.KeyDescriptor{
PubKey: testPubkey,
},
DoubleTweak: testPrivkey,
}
witness, err := input.SenderHtlcSpendRevoke(
&dummySigner{}, signDesc, testTx,
)
if err != nil {
t.Fatal(err)
}
return witness
},
},
{
name: "offered htlc timeout",
expSize: input.OfferedHtlcTimeoutWitnessSize - 3,
genWitness: func(t *testing.T) wire.TxWitness {
witScript, err := input.SenderHTLCScript(
testPubkey, testPubkey, testPubkey,
testHash160, false,
)
if err != nil {
t.Fatal(err)
}
signDesc := &input.SignDescriptor{
WitnessScript: witScript,
}
witness, err := input.SenderHtlcSpendTimeout(
&maxDERSignature{}, txscript.SigHashAll,
&dummySigner{}, signDesc, testTx,
)
if err != nil {
t.Fatal(err)
}
return witness
},
},
{
name: "offered htlc timeout confirmed",
expSize: input.OfferedHtlcTimeoutWitnessSize,
genWitness: func(t *testing.T) wire.TxWitness {
witScript, err := input.SenderHTLCScript(
testPubkey, testPubkey, testPubkey,
testHash160, true,
)
if err != nil {
t.Fatal(err)
}
signDesc := &input.SignDescriptor{
WitnessScript: witScript,
}
witness, err := input.SenderHtlcSpendTimeout(
&maxDERSignature{}, txscript.SigHashAll,
&dummySigner{}, signDesc, testTx,
)
if err != nil {
t.Fatal(err)
}
return witness
},
},
{
name: "offered htlc success",
expSize: input.OfferedHtlcSuccessWitnessSize - 3,
genWitness: func(t *testing.T) wire.TxWitness {
witScript, err := input.SenderHTLCScript(
testPubkey, testPubkey, testPubkey,
testHash160, false,
)
if err != nil {
t.Fatal(err)
}
signDesc := &input.SignDescriptor{
WitnessScript: witScript,
}
witness, err := input.SenderHtlcSpendRedeem(
&dummySigner{}, signDesc, testTx, testPreimage,
)
if err != nil {
t.Fatal(err)
}
return witness
},
},
{
name: "offered htlc success confirmed",
expSize: input.OfferedHtlcSuccessWitnessSize,
genWitness: func(t *testing.T) wire.TxWitness {
witScript, err := input.SenderHTLCScript(
testPubkey, testPubkey, testPubkey,
testHash160, true,
)
if err != nil {
t.Fatal(err)
}
signDesc := &input.SignDescriptor{
WitnessScript: witScript,
}
witness, err := input.SenderHtlcSpendRedeem(
&dummySigner{}, signDesc, testTx, testPreimage,
)
if err != nil {
t.Fatal(err)
}
return witness
},
},
{
name: "accepted htlc revoke",
expSize: input.AcceptedHtlcPenaltyWitnessSize - 3,
genWitness: func(t *testing.T) wire.TxWitness {
witScript, err := input.ReceiverHTLCScript(
testCLTVExpiry, testPubkey, testPubkey,
testPubkey, testHash160, false,
)
if err != nil {
t.Fatal(err)
}
signDesc := &input.SignDescriptor{
WitnessScript: witScript,
KeyDesc: keychain.KeyDescriptor{
PubKey: testPubkey,
},
DoubleTweak: testPrivkey,
}
witness, err := input.ReceiverHtlcSpendRevoke(
&dummySigner{}, signDesc, testTx,
)
if err != nil {
t.Fatal(err)
}
return witness
},
},
{
name: "accepted htlc revoke confirmed",
expSize: input.AcceptedHtlcPenaltyWitnessSize,
genWitness: func(t *testing.T) wire.TxWitness {
witScript, err := input.ReceiverHTLCScript(
testCLTVExpiry, testPubkey, testPubkey,
testPubkey, testHash160, true,
)
if err != nil {
t.Fatal(err)
}
signDesc := &input.SignDescriptor{
WitnessScript: witScript,
KeyDesc: keychain.KeyDescriptor{
PubKey: testPubkey,
},
DoubleTweak: testPrivkey,
}
witness, err := input.ReceiverHtlcSpendRevoke(
&dummySigner{}, signDesc, testTx,
)
if err != nil {
t.Fatal(err)
}
return witness
},
},
{
name: "accepted htlc timeout",
expSize: input.AcceptedHtlcTimeoutWitnessSize - 3,
genWitness: func(t *testing.T) wire.TxWitness {
witScript, err := input.ReceiverHTLCScript(
testCLTVExpiry, testPubkey, testPubkey,
testPubkey, testHash160, false,
)
if err != nil {
t.Fatal(err)
}
signDesc := &input.SignDescriptor{
WitnessScript: witScript,
}
witness, err := input.ReceiverHtlcSpendTimeout(
&dummySigner{}, signDesc, testTx,
testCLTVExpiry,
)
if err != nil {
t.Fatal(err)
}
return witness
},
},
{
name: "accepted htlc timeout confirmed",
expSize: input.AcceptedHtlcTimeoutWitnessSize,
genWitness: func(t *testing.T) wire.TxWitness {
witScript, err := input.ReceiverHTLCScript(
testCLTVExpiry, testPubkey, testPubkey,
testPubkey, testHash160, true,
)
if err != nil {
t.Fatal(err)
}
signDesc := &input.SignDescriptor{
WitnessScript: witScript,
}
witness, err := input.ReceiverHtlcSpendTimeout(
&dummySigner{}, signDesc, testTx,
testCLTVExpiry,
)
if err != nil {
t.Fatal(err)
}
return witness
},
},
{
name: "accepted htlc success",
expSize: input.AcceptedHtlcSuccessWitnessSize - 3,
genWitness: func(t *testing.T) wire.TxWitness {
witScript, err := input.ReceiverHTLCScript(
testCLTVExpiry, testPubkey, testPubkey,
testPubkey, testHash160, false,
)
if err != nil {
t.Fatal(err)
}
signDesc := &input.SignDescriptor{
WitnessScript: witScript,
KeyDesc: keychain.KeyDescriptor{
PubKey: testPubkey,
},
}
witness, err := input.ReceiverHtlcSpendRedeem(
&maxDERSignature{}, txscript.SigHashAll,
testPreimage, &dummySigner{}, signDesc, testTx,
)
if err != nil {
t.Fatal(err)
}
return witness
},
},
{
name: "accepted htlc success confirmed",
expSize: input.AcceptedHtlcSuccessWitnessSize,
genWitness: func(t *testing.T) wire.TxWitness {
witScript, err := input.ReceiverHTLCScript(
testCLTVExpiry, testPubkey, testPubkey,
testPubkey, testHash160, true,
)
if err != nil {
t.Fatal(err)
}
signDesc := &input.SignDescriptor{
WitnessScript: witScript,
KeyDesc: keychain.KeyDescriptor{
PubKey: testPubkey,
},
}
witness, err := input.ReceiverHtlcSpendRedeem(
&maxDERSignature{}, txscript.SigHashAll,
testPreimage, &dummySigner{}, signDesc, testTx,
)
if err != nil {
t.Fatal(err)
}
return witness
},
},
}
// TestWitnessSizes asserts the correctness of our magic witness constants.
// Witnesses involving signatures will have maxDERSignatures injected so that we
// can determine upper bounds for the witness sizes. These constants are
// predominately used for fee estimation, so we want to be certain that we
// aren't under estimating or our transactions could get stuck.
func TestWitnessSizes(t *testing.T) {
for _, test := range witnessSizeTests {
test := test
t.Run(test.name, func(t *testing.T) {
size := test.genWitness(t).SerializeSize()
if size != test.expSize {
t.Fatalf("size mismatch, want: %v, got: %v",
test.expSize, size)
}
})
}
}