lnd/watchtower/lookout/justice_descriptor_test.go
Oliver Gugger 7dfe4018ce
multi: use btcd's btcec/v2 and btcutil modules
This commit was previously split into the following parts to ease
review:
 - 2d746f68: replace imports
 - 4008f0fd: use ecdsa.Signature
 - 849e33d1: remove btcec.S256()
 - b8f6ebbd: use v2 library correctly
 - fa80bca9: bump go modules
2022-03-09 19:02:37 +01:00

371 lines
11 KiB
Go

package lookout_test
import (
"testing"
"time"
"github.com/btcsuite/btcd/blockchain"
"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/input"
"github.com/lightningnetwork/lnd/keychain"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/lightningnetwork/lnd/watchtower/blob"
"github.com/lightningnetwork/lnd/watchtower/lookout"
"github.com/lightningnetwork/lnd/watchtower/wtdb"
"github.com/lightningnetwork/lnd/watchtower/wtmock"
"github.com/lightningnetwork/lnd/watchtower/wtpolicy"
"github.com/stretchr/testify/require"
)
const csvDelay uint32 = 144
var (
revPrivBytes = []byte{
0x8f, 0x4b, 0x51, 0x83, 0xa9, 0x34, 0xbd, 0x5f,
0x74, 0x6c, 0x9d, 0x5c, 0xae, 0x88, 0x2d, 0x31,
0x06, 0x90, 0xdd, 0x8c, 0x9b, 0x31, 0xbc, 0xd1,
0x78, 0x91, 0x88, 0x2a, 0xf9, 0x74, 0xa0, 0xef,
}
toLocalPrivBytes = []byte{
0xde, 0x17, 0xc1, 0x2f, 0xdc, 0x1b, 0xc0, 0xc6,
0x59, 0x5d, 0xf9, 0xc1, 0x3e, 0x89, 0xbc, 0x6f,
0x01, 0x85, 0x45, 0x76, 0x26, 0xce, 0x9c, 0x55,
0x3b, 0xc9, 0xec, 0x3d, 0xd8, 0x8b, 0xac, 0xa8,
}
toRemotePrivBytes = []byte{
0x28, 0x59, 0x6f, 0x36, 0xb8, 0x9f, 0x19, 0x5d,
0xcb, 0x07, 0x48, 0x8a, 0xe5, 0x89, 0x71, 0x74,
0x70, 0x4c, 0xff, 0x1e, 0x9c, 0x00, 0x93, 0xbe,
0xe2, 0x2e, 0x68, 0x08, 0x4c, 0xb4, 0x0f, 0x4f,
}
rewardCommitType = blob.TypeFromFlags(
blob.FlagReward, blob.FlagCommitOutputs,
)
altruistCommitType = blob.FlagCommitOutputs.Type()
altruistAnchorCommitType = blob.TypeAltruistAnchorCommit
)
// TestJusticeDescriptor asserts that a JusticeDescriptor is able to produce the
// correct justice transaction for different blob types.
func TestJusticeDescriptor(t *testing.T) {
tests := []struct {
name string
blobType blob.Type
}{
{
name: "reward and commit type",
blobType: rewardCommitType,
},
{
name: "altruist and commit type",
blobType: altruistCommitType,
},
{
name: "altruist anchor commit type",
blobType: altruistAnchorCommitType,
},
}
for _, test := range tests {
t.Run(test.name, func(t *testing.T) {
testJusticeDescriptor(t, test.blobType)
})
}
}
func testJusticeDescriptor(t *testing.T, blobType blob.Type) {
isAnchorChannel := blobType.IsAnchorChannel()
const (
localAmount = btcutil.Amount(100000)
remoteAmount = btcutil.Amount(200000)
totalAmount = localAmount + remoteAmount
)
// Parse the key pairs for all keys used in the test.
revSK, revPK := btcec.PrivKeyFromBytes(
revPrivBytes,
)
_, toLocalPK := btcec.PrivKeyFromBytes(
toLocalPrivBytes,
)
toRemoteSK, toRemotePK := btcec.PrivKeyFromBytes(
toRemotePrivBytes,
)
// Create the signer, and add the revocation and to-remote privkeys.
signer := wtmock.NewMockSigner()
var (
revKeyLoc = signer.AddPrivKey(revSK)
toRemoteKeyLoc = signer.AddPrivKey(toRemoteSK)
)
// Construct the to-local witness script.
toLocalScript, err := input.CommitScriptToSelf(
csvDelay, toLocalPK, revPK,
)
require.Nil(t, err)
// Compute the to-local witness script hash.
toLocalScriptHash, err := input.WitnessScriptHash(toLocalScript)
require.Nil(t, err)
// Compute the to-remote redeem script, witness script hash, and
// sequence numbers.
//
// NOTE: This is pretty subtle.
//
// The actual redeem script for a p2wkh output is just the pubkey, but
// the witness sighash calculation injects the classic p2kh script:
// OP_DUP OP_HASH160 <pubkey-hash160> OP_EQUALVERIFY OP_CHECKSIG. When
// signing for p2wkh we don't pass the raw pubkey as the witness script
// to the sign descriptor (since that's also not a valid script).
// Instead we give it the _pkscript_ of the form OP_0 <pubkey-hash160>
// from which pubkey-hash160 is extracted during sighash calculation.
//
// On the other hand, signing for the anchor p2wsh to-remote outputs
// requires the sign descriptor to contain the redeem script ver batim.
// This difference in behavior forces us to use a distinct
// toRemoteSigningScript to handle both cases.
var (
toRemoteSequence uint32
toRemoteRedeemScript []byte
toRemoteScriptHash []byte
toRemoteSigningScript []byte
)
if isAnchorChannel {
toRemoteSequence = 1
toRemoteRedeemScript, err = input.CommitScriptToRemoteConfirmed(
toRemotePK,
)
require.Nil(t, err)
toRemoteScriptHash, err = input.WitnessScriptHash(
toRemoteRedeemScript,
)
require.Nil(t, err)
// As it should be.
toRemoteSigningScript = toRemoteRedeemScript
} else {
toRemoteRedeemScript = toRemotePK.SerializeCompressed()
toRemoteScriptHash, err = input.CommitScriptUnencumbered(
toRemotePK,
)
require.Nil(t, err)
// NOTE: This is the _pkscript_.
toRemoteSigningScript = toRemoteScriptHash
}
// Construct the breaching commitment txn, containing the to-local and
// to-remote outputs. We don't need any inputs for this test.
breachTxn := &wire.MsgTx{
Version: 2,
TxIn: []*wire.TxIn{},
TxOut: []*wire.TxOut{
{
Value: int64(localAmount),
PkScript: toLocalScriptHash,
},
{
Value: int64(remoteAmount),
PkScript: toRemoteScriptHash,
},
},
}
breachTxID := breachTxn.TxHash()
// Compute the weight estimate for our justice transaction.
var weightEstimate input.TxWeightEstimator
// An older ToLocalPenaltyWitnessSize constant used to underestimate the
// size by one byte. The diferrence in weight can cause different output
// values on the sweep transaction, so we mimic the original bug and
// create signatures using the original weight estimate. For anchor
// channels we fix this and use the correct witness size.
if isAnchorChannel {
weightEstimate.AddWitnessInput(input.ToLocalPenaltyWitnessSize)
} else {
weightEstimate.AddWitnessInput(input.ToLocalPenaltyWitnessSize - 1)
}
if isAnchorChannel {
weightEstimate.AddWitnessInput(input.ToRemoteConfirmedWitnessSize)
} else {
weightEstimate.AddWitnessInput(input.P2WKHWitnessSize)
}
weightEstimate.AddP2WKHOutput()
if blobType.Has(blob.FlagReward) {
weightEstimate.AddP2WKHOutput()
}
txWeight := weightEstimate.Weight()
// Create a session info so that simulate agreement of the sweep
// parameters that should be used in constructing the justice
// transaction.
policy := wtpolicy.Policy{
TxPolicy: wtpolicy.TxPolicy{
BlobType: blobType,
SweepFeeRate: 2000,
RewardRate: 900000,
},
}
sessionInfo := &wtdb.SessionInfo{
Policy: policy,
RewardAddress: makeAddrSlice(22),
}
// Begin to assemble the justice kit, starting with the sweep address,
// pubkeys, and csv delay.
justiceKit := &blob.JusticeKit{
BlobType: blobType,
SweepAddress: makeAddrSlice(22),
CSVDelay: csvDelay,
}
copy(justiceKit.RevocationPubKey[:], revPK.SerializeCompressed())
copy(justiceKit.LocalDelayPubKey[:], toLocalPK.SerializeCompressed())
copy(justiceKit.CommitToRemotePubKey[:], toRemotePK.SerializeCompressed())
// Create a transaction spending from the outputs of the breach
// transaction created earlier. The inputs are always ordered w/
// to-local and then to-remote. The outputs are always added as the
// sweep address then reward address.
justiceTxn := &wire.MsgTx{
Version: 2,
TxIn: []*wire.TxIn{
{
PreviousOutPoint: wire.OutPoint{
Hash: breachTxID,
Index: 0,
},
},
{
PreviousOutPoint: wire.OutPoint{
Hash: breachTxID,
Index: 1,
},
Sequence: toRemoteSequence,
},
},
}
outputs, err := policy.ComputeJusticeTxOuts(
totalAmount, int64(txWeight), justiceKit.SweepAddress,
sessionInfo.RewardAddress,
)
require.Nil(t, err)
// Attach the txouts and BIP69 sort the resulting transaction.
justiceTxn.TxOut = outputs
txsort.InPlaceSort(justiceTxn)
hashCache := txscript.NewTxSigHashes(justiceTxn)
// Create the sign descriptor used to sign for the to-local input.
toLocalSignDesc := &input.SignDescriptor{
KeyDesc: keychain.KeyDescriptor{
KeyLocator: revKeyLoc,
},
WitnessScript: toLocalScript,
Output: breachTxn.TxOut[0],
SigHashes: hashCache,
InputIndex: 0,
HashType: txscript.SigHashAll,
}
// Create the sign descriptor used to sign for the to-remote input.
toRemoteSignDesc := &input.SignDescriptor{
KeyDesc: keychain.KeyDescriptor{
KeyLocator: toRemoteKeyLoc,
PubKey: toRemotePK,
},
WitnessScript: toRemoteSigningScript,
Output: breachTxn.TxOut[1],
SigHashes: hashCache,
InputIndex: 1,
HashType: txscript.SigHashAll,
}
// Verify that our test justice transaction is sane.
btx := btcutil.NewTx(justiceTxn)
err = blockchain.CheckTransactionSanity(btx)
require.Nil(t, err)
// Compute a DER-encoded signature for the to-local input.
toLocalSigRaw, err := signer.SignOutputRaw(justiceTxn, toLocalSignDesc)
require.Nil(t, err)
// Compute the witness for the to-remote input. The first element is a
// DER-encoded signature under the to-remote pubkey. The sighash flag is
// also present, so we trim it.
toRemoteSigRaw, err := signer.SignOutputRaw(justiceTxn, toRemoteSignDesc)
require.Nil(t, err)
// Convert the DER to-local sig into a fixed-size signature.
toLocalSig, err := lnwire.NewSigFromSignature(toLocalSigRaw)
require.Nil(t, err)
// Convert the DER to-remote sig into a fixed-size signature.
toRemoteSig, err := lnwire.NewSigFromSignature(toRemoteSigRaw)
require.Nil(t, err)
// Complete our justice kit by copying the signatures into the payload.
copy(justiceKit.CommitToLocalSig[:], toLocalSig[:])
copy(justiceKit.CommitToRemoteSig[:], toRemoteSig[:])
justiceDesc := &lookout.JusticeDescriptor{
BreachedCommitTx: breachTxn,
SessionInfo: sessionInfo,
JusticeKit: justiceKit,
}
// Construct a breach punisher that will feed published transactions
// over the buffered channel.
publications := make(chan *wire.MsgTx, 1)
punisher := lookout.NewBreachPunisher(&lookout.PunisherConfig{
PublishTx: func(tx *wire.MsgTx, _ string) error {
publications <- tx
return nil
},
})
// Exact retribution on the offender. If no error is returned, we expect
// the justice transaction to be published via the channel.
err = punisher.Punish(justiceDesc, nil)
require.Nil(t, err)
// Retrieve the published justice transaction.
var wtJusticeTxn *wire.MsgTx
select {
case wtJusticeTxn = <-publications:
case <-time.After(50 * time.Millisecond):
t.Fatalf("punisher did not publish justice txn")
}
// Construct the test's to-local witness.
justiceTxn.TxIn[0].Witness = make([][]byte, 3)
justiceTxn.TxIn[0].Witness[0] = append(toLocalSigRaw.Serialize(),
byte(txscript.SigHashAll))
justiceTxn.TxIn[0].Witness[1] = []byte{1}
justiceTxn.TxIn[0].Witness[2] = toLocalScript
// Construct the test's to-remote witness.
justiceTxn.TxIn[1].Witness = make([][]byte, 2)
justiceTxn.TxIn[1].Witness[0] = append(toRemoteSigRaw.Serialize(),
byte(txscript.SigHashAll))
justiceTxn.TxIn[1].Witness[1] = toRemoteRedeemScript
// Assert that the watchtower derives the same justice txn.
require.Equal(t, justiceTxn, wtJusticeTxn)
}