lnd.xprv/watchtower/blob/justice_kit_test.go

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package blob_test
import (
"bytes"
"crypto/rand"
"encoding/binary"
"io"
"reflect"
"testing"
"github.com/btcsuite/btcd/btcec"
"github.com/btcsuite/btcd/txscript"
"github.com/lightningnetwork/lnd/input"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/lightningnetwork/lnd/watchtower/blob"
)
func makePubKey(i uint64) blob.PubKey {
var pk blob.PubKey
pk[0] = 0x02
if i%2 == 1 {
pk[0] |= 0x01
}
binary.BigEndian.PutUint64(pk[1:9], i)
return pk
}
func makeSig(i int) lnwire.Sig {
var sig lnwire.Sig
binary.BigEndian.PutUint64(sig[:8], uint64(i))
return sig
}
func makeAddr(size int) []byte {
addr := make([]byte, size)
if _, err := io.ReadFull(rand.Reader, addr); err != nil {
panic("unable to create addr")
}
return addr
}
type descriptorTest struct {
name string
encVersion blob.Type
decVersion blob.Type
sweepAddr []byte
revPubKey blob.PubKey
delayPubKey blob.PubKey
csvDelay uint32
commitToLocalSig lnwire.Sig
hasCommitToRemote bool
commitToRemotePubKey blob.PubKey
commitToRemoteSig lnwire.Sig
encErr error
decErr error
}
var descriptorTests = []descriptorTest{
{
name: "to-local only",
encVersion: blob.TypeAltruistCommit,
decVersion: blob.TypeAltruistCommit,
sweepAddr: makeAddr(22),
revPubKey: makePubKey(0),
delayPubKey: makePubKey(1),
csvDelay: 144,
commitToLocalSig: makeSig(1),
},
{
name: "to-local and p2wkh",
encVersion: blob.TypeRewardCommit,
decVersion: blob.TypeRewardCommit,
sweepAddr: makeAddr(22),
revPubKey: makePubKey(0),
delayPubKey: makePubKey(1),
csvDelay: 144,
commitToLocalSig: makeSig(1),
hasCommitToRemote: true,
commitToRemotePubKey: makePubKey(2),
commitToRemoteSig: makeSig(2),
},
{
name: "unknown encrypt version",
encVersion: 0,
decVersion: blob.TypeAltruistCommit,
sweepAddr: makeAddr(34),
revPubKey: makePubKey(0),
delayPubKey: makePubKey(1),
csvDelay: 144,
commitToLocalSig: makeSig(1),
encErr: blob.ErrUnknownBlobType,
},
{
name: "unknown decrypt version",
encVersion: blob.TypeAltruistCommit,
decVersion: 0,
sweepAddr: makeAddr(34),
revPubKey: makePubKey(0),
delayPubKey: makePubKey(1),
csvDelay: 144,
commitToLocalSig: makeSig(1),
decErr: blob.ErrUnknownBlobType,
},
{
name: "sweep addr length zero",
encVersion: blob.TypeAltruistCommit,
decVersion: blob.TypeAltruistCommit,
sweepAddr: makeAddr(0),
revPubKey: makePubKey(0),
delayPubKey: makePubKey(1),
csvDelay: 144,
commitToLocalSig: makeSig(1),
},
{
name: "sweep addr max size",
encVersion: blob.TypeAltruistCommit,
decVersion: blob.TypeAltruistCommit,
sweepAddr: makeAddr(blob.MaxSweepAddrSize),
revPubKey: makePubKey(0),
delayPubKey: makePubKey(1),
csvDelay: 144,
commitToLocalSig: makeSig(1),
},
{
name: "sweep addr too long",
encVersion: blob.TypeAltruistCommit,
decVersion: blob.TypeAltruistCommit,
sweepAddr: makeAddr(blob.MaxSweepAddrSize + 1),
revPubKey: makePubKey(0),
delayPubKey: makePubKey(1),
csvDelay: 144,
commitToLocalSig: makeSig(1),
encErr: blob.ErrSweepAddressToLong,
},
}
// TestBlobJusticeKitEncryptDecrypt asserts that encrypting and decrypting a
// plaintext blob produces the original. The tests include negative assertions
// when passed invalid combinations, and that all successfully encrypted blobs
// are of constant size.
func TestBlobJusticeKitEncryptDecrypt(t *testing.T) {
for _, test := range descriptorTests {
t.Run(test.name, func(t *testing.T) {
testBlobJusticeKitEncryptDecrypt(t, test)
})
}
}
func testBlobJusticeKitEncryptDecrypt(t *testing.T, test descriptorTest) {
boj := &blob.JusticeKit{
SweepAddress: test.sweepAddr,
RevocationPubKey: test.revPubKey,
LocalDelayPubKey: test.delayPubKey,
CSVDelay: test.csvDelay,
CommitToLocalSig: test.commitToLocalSig,
CommitToRemotePubKey: test.commitToRemotePubKey,
CommitToRemoteSig: test.commitToRemoteSig,
}
// Generate a random encryption key for the blob. The key is
// sized at 32 byte, as in practice we will be using the remote
// party's commitment txid as the key.
var key blob.BreachKey
_, err := rand.Read(key[:])
if err != nil {
t.Fatalf("unable to generate blob encryption key: %v", err)
}
// Encrypt the blob plaintext using the generated key and
// target version for this test.
ctxt, err := boj.Encrypt(key, test.encVersion)
if err != test.encErr {
t.Fatalf("unable to encrypt blob: %v", err)
} else if test.encErr != nil {
// If the test expected an encryption failure, we can
// continue to the next test.
return
}
// Ensure that all encrypted blobs are padded out to the same
// size: 282 bytes for version 0.
if len(ctxt) != blob.Size(test.encVersion) {
t.Fatalf("expected blob to have size %d, got %d instead",
blob.Size(test.encVersion), len(ctxt))
}
// Decrypt the encrypted blob, reconstructing the original
// blob plaintext from the decrypted contents. We use the target
// decryption version specified by this test case.
boj2, err := blob.Decrypt(key, ctxt, test.decVersion)
if err != test.decErr {
t.Fatalf("unable to decrypt blob: %v", err)
} else if test.decErr != nil {
// If the test expected an decryption failure, we can
// continue to the next test.
return
}
// Check that the decrypted blob properly reports whether it has
// a to-remote output or not.
if boj2.HasCommitToRemoteOutput() != test.hasCommitToRemote {
t.Fatalf("expected blob has_to_remote to be %v, got %v",
test.hasCommitToRemote, boj2.HasCommitToRemoteOutput())
}
// Check that the original blob plaintext matches the
// one reconstructed from the encrypted blob.
if !reflect.DeepEqual(boj, boj2) {
t.Fatalf("decrypted plaintext does not match original, "+
"want: %v, got %v", boj, boj2)
}
}
// TestJusticeKitRemoteWitnessConstruction tests that a JusticeKit returns the
// proper to-remote witnes script and to-remote witness stack. This should be
// equivalent to p2wkh spend.
func TestJusticeKitRemoteWitnessConstruction(t *testing.T) {
// Generate the to-remote pubkey.
toRemotePrivKey, err := btcec.NewPrivateKey(btcec.S256())
if err != nil {
t.Fatalf("unable to generate to-remote priv key: %v", err)
}
// Copy the to-remote pubkey into the format expected by our justice
// kit.
var toRemotePubKey blob.PubKey
copy(toRemotePubKey[:], toRemotePrivKey.PubKey().SerializeCompressed())
// Sign a message using the to-remote private key. The exact message
// doesn't matter as we won't be validating the signature's validity.
digest := bytes.Repeat([]byte("a"), 32)
rawToRemoteSig, err := toRemotePrivKey.Sign(digest)
if err != nil {
t.Fatalf("unable to generate to-remote signature: %v", err)
}
// Convert the DER-encoded signature into a fixed-size sig.
commitToRemoteSig, err := lnwire.NewSigFromSignature(rawToRemoteSig)
if err != nil {
t.Fatalf("unable to convert raw to-remote signature to "+
"Sig: %v", err)
}
// Populate the justice kit fields relevant to the to-remote output.
justiceKit := &blob.JusticeKit{
CommitToRemotePubKey: toRemotePubKey,
CommitToRemoteSig: commitToRemoteSig,
}
// Now, compute the to-remote witness script returned by the justice
// kit.
toRemoteScript, err := justiceKit.CommitToRemoteWitnessScript()
if err != nil {
t.Fatalf("unable to compute to-remote witness script: %v", err)
}
// Assert this is exactly the to-remote, compressed pubkey.
if !bytes.Equal(toRemoteScript, toRemotePubKey[:]) {
t.Fatalf("to-remote witness script should be equal to "+
"to-remote pubkey, want: %x, got %x",
toRemotePubKey[:], toRemoteScript)
}
// Next, compute the to-remote witness stack, which should be a p2wkh
// witness stack consisting solely of a signature.
toRemoteWitnessStack, err := justiceKit.CommitToRemoteWitnessStack()
if err != nil {
t.Fatalf("unable to compute to-remote witness stack: %v", err)
}
// Assert that the witness stack only has one element.
if len(toRemoteWitnessStack) != 1 {
t.Fatalf("to-remote witness stack should be of length 1, is %d",
len(toRemoteWitnessStack))
}
// Compute the expected first element, by appending a sighash all byte
// to our raw DER-encoded signature.
rawToRemoteSigWithSigHash := append(
rawToRemoteSig.Serialize(), byte(txscript.SigHashAll),
)
// Assert that the expected signature matches the first element in the
// witness stack.
if !bytes.Equal(rawToRemoteSigWithSigHash, toRemoteWitnessStack[0]) {
t.Fatalf("mismatched sig in to-remote witness stack, want: %v, "+
"got: %v", rawToRemoteSigWithSigHash,
toRemoteWitnessStack[0])
}
// Finally, set the CommitToRemotePubKey to be a blank value.
justiceKit.CommitToRemotePubKey = blob.PubKey{}
// When trying to compute the witness script, this should now return
// ErrNoCommitToRemoteOutput since a valid pubkey could not be parsed
// from CommitToRemotePubKey.
_, err = justiceKit.CommitToRemoteWitnessScript()
if err != blob.ErrNoCommitToRemoteOutput {
t.Fatalf("expected ErrNoCommitToRemoteOutput, got: %v", err)
}
}
// TestJusticeKitToLocalWitnessConstruction tests that a JusticeKit returns the
// proper to-local witness script and to-local witness stack for spending the
// revocation path.
func TestJusticeKitToLocalWitnessConstruction(t *testing.T) {
csvDelay := uint32(144)
// Generate the revocation and delay private keys.
revPrivKey, err := btcec.NewPrivateKey(btcec.S256())
if err != nil {
t.Fatalf("unable to generate revocation priv key: %v", err)
}
delayPrivKey, err := btcec.NewPrivateKey(btcec.S256())
if err != nil {
t.Fatalf("unable to generate delay priv key: %v", err)
}
// Copy the revocation and delay pubkeys into the format expected by our
// justice kit.
var revPubKey blob.PubKey
copy(revPubKey[:], revPrivKey.PubKey().SerializeCompressed())
var delayPubKey blob.PubKey
copy(delayPubKey[:], delayPrivKey.PubKey().SerializeCompressed())
// Sign a message using the revocation private key. The exact message
// doesn't matter as we won't be validating the signature's validity.
digest := bytes.Repeat([]byte("a"), 32)
rawRevSig, err := revPrivKey.Sign(digest)
if err != nil {
t.Fatalf("unable to generate revocation signature: %v", err)
}
// Convert the DER-encoded signature into a fixed-size sig.
commitToLocalSig, err := lnwire.NewSigFromSignature(rawRevSig)
if err != nil {
t.Fatalf("unable to convert raw revocation signature to "+
"Sig: %v", err)
}
// Populate the justice kit with fields relevant to the to-local output.
justiceKit := &blob.JusticeKit{
CSVDelay: csvDelay,
RevocationPubKey: revPubKey,
LocalDelayPubKey: delayPubKey,
CommitToLocalSig: commitToLocalSig,
}
// Compute the expected to-local script, which is a function of the CSV
// delay, revocation pubkey and delay pubkey.
expToLocalScript, err := input.CommitScriptToSelf(
csvDelay, delayPrivKey.PubKey(), revPrivKey.PubKey(),
)
if err != nil {
t.Fatalf("unable to generate expected to-local script: %v", err)
}
// Compute the to-local script that is returned by the justice kit.
toLocalScript, err := justiceKit.CommitToLocalWitnessScript()
if err != nil {
t.Fatalf("unable to compute to-local witness script: %v", err)
}
// Assert that the expected to-local script matches the actual script.
if !bytes.Equal(expToLocalScript, toLocalScript) {
t.Fatalf("mismatched to-local witness script, want: %v, got %v",
expToLocalScript, toLocalScript)
}
// Next, compute the to-local witness stack returned by the justice kit.
toLocalWitnessStack, err := justiceKit.CommitToLocalRevokeWitnessStack()
if err != nil {
t.Fatalf("unable to compute to-local witness stack: %v", err)
}
// A valid witness that spends the revocation path should have exactly
// two elements on the stack.
if len(toLocalWitnessStack) != 2 {
t.Fatalf("to-local witness stack should be of length 2, is %d",
len(toLocalWitnessStack))
}
// First, we'll verify that the top element is 0x01, which triggers the
// revocation path within the to-local witness script.
if !bytes.Equal(toLocalWitnessStack[1], []byte{0x01}) {
t.Fatalf("top item on witness stack should be 0x01, found: %v",
toLocalWitnessStack[1])
}
// Next, compute the expected signature in the bottom element of the
// stack, by appending a sighash all flag to the raw DER signature.
rawRevSigWithSigHash := append(
rawRevSig.Serialize(), byte(txscript.SigHashAll),
)
// Assert that the second element on the stack matches our expected
// signature under the revocation pubkey.
if !bytes.Equal(rawRevSigWithSigHash, toLocalWitnessStack[0]) {
t.Fatalf("mismatched sig in to-local witness stack, want: %v, "+
"got: %v", rawRevSigWithSigHash, toLocalWitnessStack[0])
}
}