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Merge pull request #2439 from cfromknecht/wtpolicy-blob-type

Browse Source 
wtpolicy: migrate to using wtpolicy.Policy + blob bitvector flags
This commit is contained in:
Olaoluwa Osuntokun 2019-01-15 19:30:56 -08:00 committed by GitHub
commit 53a181ce49
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
14 changed files with 677 additions and 92 deletions
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46
watchtower/blob/justice_kit.go
View File

@ -17,12 +17,6 @@ import (
)
const (
// MinVersion is the minimum blob version supported by this package.
MinVersion = 0
// MaxVersion is the maximumm blob version supported by this package.
MaxVersion = 0
// NonceSize is the length of a chacha20poly1305 nonce, 24 bytes.
NonceSize = chacha20poly1305.NonceSizeX
@ -53,14 +47,14 @@ const (
// nonce: 24 bytes
// enciphered plaintext: n bytes
// MAC: 16 bytes
func Size(ver uint16) int {
return NonceSize + PlaintextSize(ver) + CiphertextExpansion
func Size(blobType Type) int {
return NonceSize + PlaintextSize(blobType) + CiphertextExpansion
}
// PlaintextSize returns the size of the encoded-but-unencrypted blob in bytes.
func PlaintextSize(ver uint16) int {
switch ver {
case 0:
func PlaintextSize(blobType Type) int {
switch {
case blobType.Has(FlagCommitOutputs):
return V0PlaintextSize
default:
return 0
@ -71,9 +65,9 @@ var (
// byteOrder specifies a big-endian encoding of all integer values.
byteOrder = binary.BigEndian
// ErrUnknownBlobVersion signals that we don't understand the requested
// ErrUnknownBlobType signals that we don't understand the requested
// blob encoding scheme.
ErrUnknownBlobVersion = errors.New("unknown blob version")
ErrUnknownBlobType = errors.New("unknown blob type")
// ErrCiphertextTooSmall is a decryption error signaling that the
// ciphertext is smaller than the ciphertext expansion factor.
@ -229,7 +223,7 @@ func (b *JusticeKit) CommitToRemoteWitnessStack() ([][]byte, error) {
//
// NOTE: It is the caller's responsibility to ensure that this method is only
// called once for a given (nonce, key) pair.
func (b *JusticeKit) Encrypt(key []byte, version uint16) ([]byte, error) {
func (b *JusticeKit) Encrypt(key []byte, blobType Type) ([]byte, error) {
// Fail if the nonce is not 32-bytes.
if len(key) != KeySize {
return nil, ErrKeySize
@ -238,7 +232,7 @@ func (b *JusticeKit) Encrypt(key []byte, version uint16) ([]byte, error) {
// Encode the plaintext using the provided version, to obtain the
// plaintext bytes.
var ptxtBuf bytes.Buffer
err := b.encode(&ptxtBuf, version)
err := b.encode(&ptxtBuf, blobType)
if err != nil {
return nil, err
}
@ -252,7 +246,7 @@ func (b *JusticeKit) Encrypt(key []byte, version uint16) ([]byte, error) {
// Allocate the ciphertext, which will contain the nonce, encrypted
// plaintext and MAC.
plaintext := ptxtBuf.Bytes()
ciphertext := make([]byte, Size(version))
ciphertext := make([]byte, Size(blobType))
// Generate a random 24-byte nonce in the ciphertext's prefix.
nonce := ciphertext[:NonceSize]
@ -270,7 +264,7 @@ func (b *JusticeKit) Encrypt(key []byte, version uint16) ([]byte, error) {
// Decrypt unenciphers a blob of justice by decrypting the ciphertext using
// chacha20poly1305 with the chosen (nonce, key) pair. The internal plaintext is
// then deserialized using the given encoding version.
func Decrypt(key, ciphertext []byte, version uint16) (*JusticeKit, error) {
func Decrypt(key, ciphertext []byte, blobType Type) (*JusticeKit, error) {
switch {
// Fail if the blob's overall length is less than required for the nonce
@ -305,7 +299,7 @@ func Decrypt(key, ciphertext []byte, version uint16) (*JusticeKit, error) {
// If decryption succeeded, we will then decode the plaintext bytes
// using the specified blob version.
boj := &JusticeKit{}
err = boj.decode(bytes.NewReader(plaintext), version)
err = boj.decode(bytes.NewReader(plaintext), blobType)
if err != nil {
return nil, err
}
@ -315,23 +309,23 @@ func Decrypt(key, ciphertext []byte, version uint16) (*JusticeKit, error) {
// encode serializes the JusticeKit according to the version, returning an
// error if the version is unknown.
func (b *JusticeKit) encode(w io.Writer, ver uint16) error {
switch ver {
case 0:
func (b *JusticeKit) encode(w io.Writer, blobType Type) error {
switch {
case blobType.Has(FlagCommitOutputs):
return b.encodeV0(w)
default:
return ErrUnknownBlobVersion
return ErrUnknownBlobType
}
}
// decode deserializes the JusticeKit according to the version, returning an
// error if the version is unknown.
func (b *JusticeKit) decode(r io.Reader, ver uint16) error {
switch ver {
case 0:
func (b *JusticeKit) decode(r io.Reader, blobType Type) error {
switch {
case blobType.Has(FlagCommitOutputs):
return b.decodeV0(r)
default:
return ErrUnknownBlobVersion
return ErrUnknownBlobType
}
}

236
watchtower/blob/justice_kit_test.go
View File

@ -1,12 +1,16 @@
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/lnwallet"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/lightningnetwork/lnd/watchtower/blob"
)
@ -38,8 +42,8 @@ func makeAddr(size int) []byte {
type descriptorTest struct {
name string
encVersion uint16
decVersion uint16
encVersion blob.Type
decVersion blob.Type
sweepAddr []byte
revPubKey blob.PubKey
delayPubKey blob.PubKey
@ -52,11 +56,15 @@ type descriptorTest struct {
decErr error
}
var rewardAndCommitType = blob.TypeFromFlags(
blob.FlagReward, blob.FlagCommitOutputs,
)
var descriptorTests = []descriptorTest{
{
name: "to-local only",
encVersion: 0,
decVersion: 0,
encVersion: blob.TypeDefault,
decVersion: blob.TypeDefault,
sweepAddr: makeAddr(22),
revPubKey: makePubKey(0),
delayPubKey: makePubKey(1),
@ -65,8 +73,8 @@ var descriptorTests = []descriptorTest{
},
{
name: "to-local and p2wkh",
encVersion: 0,
decVersion: 0,
encVersion: rewardAndCommitType,
decVersion: rewardAndCommitType,
sweepAddr: makeAddr(22),
revPubKey: makePubKey(0),
delayPubKey: makePubKey(1),
@ -78,30 +86,30 @@ var descriptorTests = []descriptorTest{
},
{
name: "unknown encrypt version",
encVersion: 1,
decVersion: 0,
encVersion: 0,
decVersion: blob.TypeDefault,
sweepAddr: makeAddr(34),
revPubKey: makePubKey(0),
delayPubKey: makePubKey(1),
csvDelay: 144,
commitToLocalSig: makeSig(1),
encErr: blob.ErrUnknownBlobVersion,
encErr: blob.ErrUnknownBlobType,
},
{
name: "unknown decrypt version",
encVersion: 0,
decVersion: 1,
encVersion: blob.TypeDefault,
decVersion: 0,
sweepAddr: makeAddr(34),
revPubKey: makePubKey(0),
delayPubKey: makePubKey(1),
csvDelay: 144,
commitToLocalSig: makeSig(1),
decErr: blob.ErrUnknownBlobVersion,
decErr: blob.ErrUnknownBlobType,
},
{
name: "sweep addr length zero",
encVersion: 0,
decVersion: 0,
encVersion: blob.TypeDefault,
decVersion: blob.TypeDefault,
sweepAddr: makeAddr(0),
revPubKey: makePubKey(0),
delayPubKey: makePubKey(1),
@ -110,8 +118,8 @@ var descriptorTests = []descriptorTest{
},
{
name: "sweep addr max size",
encVersion: 0,
decVersion: 0,
encVersion: blob.TypeDefault,
decVersion: blob.TypeDefault,
sweepAddr: makeAddr(blob.MaxSweepAddrSize),
revPubKey: makePubKey(0),
delayPubKey: makePubKey(1),
@ -120,8 +128,8 @@ var descriptorTests = []descriptorTest{
},
{
name: "sweep addr too long",
encVersion: 0,
decVersion: 0,
encVersion: blob.TypeDefault,
decVersion: blob.TypeDefault,
sweepAddr: makeAddr(blob.MaxSweepAddrSize + 1),
revPubKey: makePubKey(0),
delayPubKey: makePubKey(1),
@ -208,3 +216,195 @@ func testBlobJusticeKitEncryptDecrypt(t *testing.T, test descriptorTest) {
"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 := lnwallet.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])
}
}

134
watchtower/blob/type.go Normal file
View File

@ -0,0 +1,134 @@
package blob
import (
"fmt"
"strings"
)
// Flag represents a specify option that can be present in a Type.
type Flag uint16
const (
// FlagReward signals that the justice transaction should contain an
// additional output for itself. Signatures sent by the client should
// include the reward script negotiated during session creation. Without
// the flag, there is only one output sweeping clients funds back to
// them solely.
FlagReward Flag = 1 << iota
// FlagCommitOutputs signals that the blob contains the information
// required to sweep commitment outputs.
FlagCommitOutputs
)
// Type returns a Type consisting solely of this flag enabled.
func (f Flag) Type() Type {
return Type(f)
}
// String returns the name of the flag.
func (f Flag) String() string {
switch f {
case FlagReward:
return "FlagReward"
case FlagCommitOutputs:
return "FlagCommitOutputs"
default:
return "FlagUnknown"
}
}
// Type is a bit vector composed of Flags that govern various aspects of
// reconstructing the justice transaction from an encrypted blob. The flags can
// be used to signal behaviors such as which inputs are being swept, which
// outputs should be added to the justice transaction, or modify serialization
// of the blob itself.
type Type uint16
// TypeDefault sweeps only commitment outputs to a sweep address controlled by
// the user, and does not give the tower a reward.
const TypeDefault = Type(FlagCommitOutputs)
// Has returns true if the Type has the passed flag enabled.
func (t Type) Has(flag Flag) bool {
return Flag(t)&flag == flag
}
// TypeFromFlags creates a single Type from an arbitrary list of flags.
func TypeFromFlags(flags ...Flag) Type {
var typ Type
for _, flag := range flags {
typ |= Type(flag)
}
return typ
}
// knownFlags maps the supported flags to their name.
var knownFlags = map[Flag]struct{}{
FlagReward: {},
FlagCommitOutputs: {},
}
// String returns a human readable description of a Type.
func (t Type) String() string {
var (
hrPieces []string
hasUnknownFlags bool
)
// Iterate through the possible flags from highest to lowest. This will
// ensure that the human readable names will be in the same order as the
// bits (left to right) if the type were to be printed in big-endian
// byte order.
for f := Flag(1 << 15); f != 0; f >>= 1 {
// If this flag is known, we'll add a human-readable name or its
// inverse depending on whether the type has this flag set.
if _, ok := knownFlags[f]; ok {
if t.Has(f) {
hrPieces = append(hrPieces, f.String())
} else {
hrPieces = append(hrPieces, "No-"+f.String())
}
} else {
// Make note of any unknown flags that this type has
// set. If any are present, we'll prepend the bit-wise
// representation of the type in the final string.
if t.Has(f) {
hasUnknownFlags = true
}
}
}
// If there were no unknown flags, we'll simply return the list of human
// readable pieces.
if !hasUnknownFlags {
return fmt.Sprintf("[%s]", strings.Join(hrPieces, "|"))
}
// Otherwise, we'll prepend the bit-wise representation to the human
// readable names.
return fmt.Sprintf("%016b[%s]", t, strings.Join(hrPieces, "|"))
}
// supportedTypes is the set of all configurations known to be supported by the
// package.
var supportedTypes = map[Type]struct{}{
FlagCommitOutputs.Type(): {},
(FlagCommitOutputs | FlagReward).Type(): {},
}
// IsSupportedType returns true if the given type is supported by the package.
func IsSupportedType(blobType Type) bool {
_, ok := supportedTypes[blobType]
return ok
}
// SupportedTypes returns a list of all supported blob types.
func SupportedTypes() []Type {
supported := make([]Type, 0, len(supportedTypes))
for t := range supportedTypes {
supported = append(supported, t)
}
return supported
}

135
watchtower/blob/type_test.go Normal file
View File

@ -0,0 +1,135 @@
package blob_test
import (
"testing"
"github.com/lightningnetwork/lnd/watchtower/blob"
)
var unknownFlag = blob.Flag(16)
type typeStringTest struct {
name string
typ blob.Type
expStr string
}
var typeStringTests = []typeStringTest{
{
name: "commit no-reward",
typ: blob.TypeDefault,
expStr: "[FlagCommitOutputs|No-FlagReward]",
},
{
name: "commit reward",
typ: (blob.FlagCommitOutputs | blob.FlagReward).Type(),
expStr: "[FlagCommitOutputs|FlagReward]",
},
{
name: "unknown flag",
typ: unknownFlag.Type(),
expStr: "0000000000010000[No-FlagCommitOutputs|No-FlagReward]",
},
}
// TestTypeStrings asserts that the proper human-readable string is returned for
// various blob.Types
func TestTypeStrings(t *testing.T) {
for _, test := range typeStringTests {
t.Run(test.name, func(t *testing.T) {
typeStr := test.typ.String()
if typeStr != test.expStr {
t.Fatalf("mismatched type string, want: %v, "+
"got %v", test.expStr, typeStr)
}
})
}
}
// TestUnknownFlagString asserts that the proper string is returned from
// unallocated flags.
func TestUnknownFlagString(t *testing.T) {
if unknownFlag.String() != "FlagUnknown" {
t.Fatalf("unknown flags should return FlagUnknown, instead "+
"got: %v", unknownFlag.String())
}
}
type typeFromFlagTest struct {
name string
flags []blob.Flag
expType blob.Type
}
var typeFromFlagTests = []typeFromFlagTest{
{
name: "no flags",
flags: nil,
expType: blob.Type(0),
},
{
name: "single flag",
flags: []blob.Flag{blob.FlagReward},
expType: blob.Type(blob.FlagReward),
},
{
name: "multiple flags",
flags: []blob.Flag{blob.FlagReward, blob.FlagCommitOutputs},
expType: blob.Type(blob.FlagReward | blob.FlagCommitOutputs),
},
{
name: "duplicate flag",
flags: []blob.Flag{blob.FlagReward, blob.FlagReward},
expType: blob.Type(blob.FlagReward),
},
}
// TestTypeFromFlags asserts that blob.Types constructed using
// blob.TypeFromFlags are correct, and properly deduplicate flags. We also
// assert that Has returns true for the generated blob.Type for all of the flags
// that were used to create it.
func TestTypeFromFlags(t *testing.T) {
for _, test := range typeFromFlagTests {
t.Run(test.name, func(t *testing.T) {
blobType := blob.TypeFromFlags(test.flags...)
// Assert that the constructed type matches our
// expectation.
if blobType != test.expType {
t.Fatalf("mismatch, expected blob type %s, "+
"got %s", test.expType, blobType)
}
// Assert that Has returns true for all flags used to
// construct the type.
for _, flag := range test.flags {
if blobType.Has(flag) {
continue
}
t.Fatalf("expected type to have flag %s, "+
"but didn't", flag)
}
})
}
}
// TestSupportedTypes verifies that blob.IsSupported returns true for all
// blob.Types returned from blob.SupportedTypes. It also asserts that the
// blob.DefaultType returns true.
func TestSupportedTypes(t *testing.T) {
// Assert that the package's default type is supported.
if !blob.IsSupportedType(blob.TypeDefault) {
t.Fatalf("default type %s is not supported", blob.TypeDefault)
}
// Assert that all claimed supported types are actually supported.
for _, supType := range blob.SupportedTypes() {
if blob.IsSupportedType(supType) {
continue
}
t.Fatalf("supposedly supported type %s is not supported",
supType)
}
}

7
watchtower/lookout/justice_descriptor_test.go
View File

@ -19,6 +19,7 @@ import (
"github.com/lightningnetwork/lnd/watchtower/blob"
"github.com/lightningnetwork/lnd/watchtower/lookout"
"github.com/lightningnetwork/lnd/watchtower/wtdb"
"github.com/lightningnetwork/lnd/watchtower/wtpolicy"
)
const csvDelay uint32 = 144
@ -170,8 +171,10 @@ func TestJusticeDescriptor(t *testing.T) {
// parameters that should be used in constructing the justice
// transaction.
sessionInfo := &wtdb.SessionInfo{
SweepFeeRate: 2000,
RewardRate: 900000,
Policy: wtpolicy.Policy{
SweepFeeRate: 2000,
RewardRate: 900000,
},
RewardAddress: makeAddrSlice(22),
}

2
watchtower/lookout/lookout.go
View File

@ -210,7 +210,7 @@ func (l *Lookout) processEpoch(epoch *chainntnfs.BlockEpoch,
// sweep the breached commitment outputs.
justiceKit, err := blob.Decrypt(
commitTxID[:], match.EncryptedBlob,
match.SessionInfo.Version,
match.SessionInfo.Policy.BlobType,
)
if err != nil {
// If the decryption fails, this implies either that the

23
watchtower/lookout/lookout_test.go
View File

@ -15,6 +15,7 @@ import (
"github.com/lightningnetwork/lnd/watchtower/blob"
"github.com/lightningnetwork/lnd/watchtower/lookout"
"github.com/lightningnetwork/lnd/watchtower/wtdb"
"github.com/lightningnetwork/lnd/watchtower/wtpolicy"
)
type mockPunisher struct {
@ -86,15 +87,25 @@ func TestLookoutBreachMatching(t *testing.T) {
t.Fatalf("unable to start watcher: %v", err)
}
rewardAndCommitType := blob.TypeFromFlags(
blob.FlagReward, blob.FlagCommitOutputs,
)
// Create two sessions, representing two distinct clients.
sessionInfo1 := &wtdb.SessionInfo{
ID: makeArray33(1),
MaxUpdates: 10,
ID: makeArray33(1),
Policy: wtpolicy.Policy{
BlobType: rewardAndCommitType,
MaxUpdates: 10,
},
RewardAddress: makeAddrSlice(22),
}
sessionInfo2 := &wtdb.SessionInfo{
ID: makeArray33(2),
MaxUpdates: 10,
ID: makeArray33(2),
Policy: wtpolicy.Policy{
BlobType: rewardAndCommitType,
MaxUpdates: 10,
},
RewardAddress: makeAddrSlice(22),
}
@ -137,13 +148,13 @@ func TestLookoutBreachMatching(t *testing.T) {
}
// Encrypt the first justice kit under the txid of the first txn.
encBlob1, err := blob1.Encrypt(hash1[:], 0)
encBlob1, err := blob1.Encrypt(hash1[:], blob.FlagCommitOutputs.Type())
if err != nil {
t.Fatalf("unable to encrypt sweep detail 1: %v", err)
}
// Encrypt the second justice kit under the txid of the second txn.
encBlob2, err := blob2.Encrypt(hash2[:], 0)
encBlob2, err := blob2.Encrypt(hash2[:], blob.FlagCommitOutputs.Type())
if err != nil {
t.Fatalf("unable to encrypt sweep detail 2: %v", err)
}

25
watchtower/wtdb/session_info.go
View File

@ -4,7 +4,7 @@ import (
"errors"
"github.com/btcsuite/btcutil"
"github.com/lightningnetwork/lnd/lnwallet"
"github.com/lightningnetwork/lnd/watchtower/wtpolicy"
)
var (
@ -49,12 +49,8 @@ type SessionInfo struct {
// ID is the remote public key of the watchtower client.
ID SessionID
// Version specifies the plaintext blob encoding of all state updates.
Version uint16
// MaxUpdates is the total number of updates the client can send for
// this session.
MaxUpdates uint16
// Policy holds the negotiated session parameters.
Policy wtpolicy.Policy
// LastApplied the sequence number of the last successful state update.
LastApplied uint16
@ -62,14 +58,6 @@ type SessionInfo struct {
// ClientLastApplied the last last-applied the client has echoed back.
ClientLastApplied uint16
// RewardRate the fraction of the swept amount that goes to the tower,
// expressed in millionths of the swept balance.
RewardRate uint32
// SweepFeeRate is the agreed upon fee rate used to sign any sweep
// transactions.
SweepFeeRate lnwallet.SatPerKWeight
// RewardAddress the address that the tower's reward will be deposited
// to if a sweep transaction confirms.
RewardAddress []byte
@ -96,7 +84,7 @@ func (s *SessionInfo) AcceptUpdateSequence(seqNum, lastApplied uint16) error {
return ErrLastAppliedReversion
// Client update exceeds capacity of session.
case seqNum > s.MaxUpdates:
case seqNum > s.Policy.MaxUpdates:
return ErrSessionConsumed
// Client update does not match our expected next seqnum.
@ -117,7 +105,7 @@ func (s *SessionInfo) AcceptUpdateSequence(seqNum, lastApplied uint16) error {
func (s *SessionInfo) ComputeSweepOutputs(totalAmt btcutil.Amount,
txVSize int64) (btcutil.Amount, btcutil.Amount, error) {
txFee := s.SweepFeeRate.FeeForWeight(txVSize)
txFee := s.Policy.SweepFeeRate.FeeForWeight(txVSize)
if txFee > totalAmt {
return 0, 0, ErrFeeExceedsInputs
}
@ -126,7 +114,8 @@ func (s *SessionInfo) ComputeSweepOutputs(totalAmt btcutil.Amount,
// Apply the reward rate to the remaining total, specified in millionths
// of the available balance.
rewardAmt := (totalAmt*btcutil.Amount(s.RewardRate) + 999999) / 1000000
rewardRate := btcutil.Amount(s.Policy.RewardRate)
rewardAmt := (totalAmt*rewardRate + 999999) / 1000000
sweepAmt := totalAmt - rewardAmt
// TODO(conner): check dustiness

68
watchtower/wtpolicy/policy.go Normal file
View File

@ -0,0 +1,68 @@
package wtpolicy
import (
"fmt"
"github.com/lightningnetwork/lnd/lnwallet"
"github.com/lightningnetwork/lnd/watchtower/blob"
)
const (
// DefaultMaxUpdates specifies the number of encrypted blobs a client
// can send to the tower in a single session.
DefaultMaxUpdates = 1024
// DefaultRewardRate specifies the fraction of the channel that the
// tower takes if it successfully sweeps a breach. The value is
// expressed in millionths of the channel capacity.
DefaultRewardRate = 10000
// DefaultSweepFeeRate specifies the fee rate used to construct justice
// transactions. The value is expressed in satoshis per kilo-weight.
DefaultSweepFeeRate = 3000
)
// DefaultPolicy returns a Policy containing the default parameters that can be
// used by clients or servers.
func DefaultPolicy() Policy {
return Policy{
BlobType: blob.TypeDefault,
MaxUpdates: DefaultMaxUpdates,
RewardRate: DefaultRewardRate,
SweepFeeRate: lnwallet.SatPerKWeight(
DefaultSweepFeeRate,
),
}
}
// Policy defines the negotiated parameters for a session between a client and
// server. The parameters specify the format of encrypted blobs sent to the
// tower, the reward schedule for the tower, and the number of encrypted blobs a
// client can send in one session.
type Policy struct {
// BlobType specifies the blob format that must be used by all updates sent
// under the session key used to negotiate this session.
BlobType blob.Type
// MaxUpdates is the maximum number of updates the watchtower will honor
// for this session.
MaxUpdates uint16
// RewardRate is the fraction of the total balance of the revoked
// commitment that the watchtower is entitled to. This value is
// expressed in millionths of the total balance.
RewardRate uint32
// SweepFeeRate expresses the intended fee rate to be used when
// constructing the justice transaction. All sweep transactions created
// for this session must use this value during construction, and the
// signatures must implicitly commit to the resulting output values.
SweepFeeRate lnwallet.SatPerKWeight
}
// String returns a human-readable description of the current policy.
func (p Policy) String() string {
return fmt.Sprintf("(blob-type=%b max-updates=%d reward-rate=%d "+
"sweep-fee-rate=%d)", p.BlobType, p.MaxUpdates, p.RewardRate,
p.SweepFeeRate)
}

27
watchtower/wtserver/server.go
View File

@ -13,7 +13,9 @@ import (
"github.com/btcsuite/btcd/connmgr"
"github.com/btcsuite/btcutil"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/lightningnetwork/lnd/watchtower/blob"
"github.com/lightningnetwork/lnd/watchtower/wtdb"
"github.com/lightningnetwork/lnd/watchtower/wtpolicy"
"github.com/lightningnetwork/lnd/watchtower/wtwire"
)
@ -246,14 +248,14 @@ func (s *Server) handleClient(peer Peer) {
log.Infof("Received CreateSession from %s, "+
"version=%d nupdates=%d rewardrate=%d "+
"sweepfeerate=%d", id, msg.BlobVersion,
"sweepfeerate=%d", id, msg.BlobType,
msg.MaxUpdates, msg.RewardRate,
msg.SweepFeeRate)
// Attempt to open a new session for this client.
err := s.handleCreateSession(peer, &id, msg)
if err != nil {
log.Errorf("unable to handle CreateSession "+
log.Errorf("Unable to handle CreateSession "+
"from %s: %v", id, err)
}
@ -327,7 +329,7 @@ func (s *Server) handleInit(localInit, remoteInit *wtwire.Init) error {
// session info is known about the session id. If an existing session is found,
// the reward address is returned in case the client lost our reply.
func (s *Server) handleCreateSession(peer Peer, id *wtdb.SessionID,
init *wtwire.CreateSession) error {
req *wtwire.CreateSession) error {
// TODO(conner): validate accept against policy
@ -369,17 +371,28 @@ func (s *Server) handleCreateSession(peer Peer, id *wtdb.SessionID,
rewardAddrBytes := rewardAddress.ScriptAddress()
// Ensure that the requested blob type is supported by our tower.
if !blob.IsSupportedType(req.BlobType) {
log.Debugf("Rejecting CreateSession from %s, unsupported blob "+
"type %s", id, req.BlobType)
return s.replyCreateSession(
peer, id, wtwire.CreateSessionCodeRejectBlobType, nil,
)
}
// TODO(conner): create invoice for upfront payment
// Assemble the session info using the agreed upon parameters, reward
// address, and session id.
info := wtdb.SessionInfo{
ID: *id,
Version: init.BlobVersion,
MaxUpdates: init.MaxUpdates,
RewardRate: init.RewardRate,
SweepFeeRate: init.SweepFeeRate,
RewardAddress: rewardAddrBytes,
Policy: wtpolicy.Policy{
BlobType: req.BlobType,
MaxUpdates: req.MaxUpdates,
RewardRate: req.RewardRate,
SweepFeeRate: req.SweepFeeRate,
},
}
// Insert the session info into the watchtower's database. If

36
watchtower/wtserver/server_test.go
View File

@ -12,6 +12,7 @@ import (
"github.com/btcsuite/btcd/chaincfg"
"github.com/btcsuite/btcutil"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/lightningnetwork/lnd/watchtower/blob"
"github.com/lightningnetwork/lnd/watchtower/wtdb"
"github.com/lightningnetwork/lnd/watchtower/wtserver"
"github.com/lightningnetwork/lnd/watchtower/wtwire"
@ -155,7 +156,7 @@ var createSessionTests = []createSessionTestCase{
lnwire.NewRawFeatureVector(),
),
createMsg: &wtwire.CreateSession{
BlobVersion: 0,
BlobType: blob.TypeDefault,
MaxUpdates: 1000,
RewardRate: 0,
SweepFeeRate: 1,
@ -169,6 +170,23 @@ var createSessionTests = []createSessionTestCase{
Data: []byte(addr.ScriptAddress()),
},
},
{
name: "reject unsupported blob type",
initMsg: wtwire.NewInitMessage(
lnwire.NewRawFeatureVector(),
lnwire.NewRawFeatureVector(),
),
createMsg: &wtwire.CreateSession{
BlobType: 0,
MaxUpdates: 1000,
RewardRate: 0,
SweepFeeRate: 1,
},
expReply: &wtwire.CreateSessionReply{
Code: wtwire.CreateSessionCodeRejectBlobType,
Data: []byte{},
},
},
// TODO(conner): add policy rejection tests
}
@ -258,7 +276,7 @@ var stateUpdateTests = []stateUpdateTestCase{
GlobalFeatures: lnwire.NewRawFeatureVector(),
}},
createMsg: &wtwire.CreateSession{
BlobVersion: 0,
BlobType: blob.TypeDefault,
MaxUpdates: 3,
RewardRate: 0,
SweepFeeRate: 1,
@ -287,7 +305,7 @@ var stateUpdateTests = []stateUpdateTestCase{
GlobalFeatures: lnwire.NewRawFeatureVector(),
}},
createMsg: &wtwire.CreateSession{
BlobVersion: 0,
BlobType: blob.TypeDefault,
MaxUpdates: 4,
RewardRate: 0,
SweepFeeRate: 1,
@ -310,7 +328,7 @@ var stateUpdateTests = []stateUpdateTestCase{
GlobalFeatures: lnwire.NewRawFeatureVector(),
}},
createMsg: &wtwire.CreateSession{
BlobVersion: 0,
BlobType: blob.TypeDefault,
MaxUpdates: 4,
RewardRate: 0,
SweepFeeRate: 1,
@ -337,7 +355,7 @@ var stateUpdateTests = []stateUpdateTestCase{
GlobalFeatures: lnwire.NewRawFeatureVector(),
}},
createMsg: &wtwire.CreateSession{
BlobVersion: 0,
BlobType: blob.TypeDefault,
MaxUpdates: 4,
RewardRate: 0,
SweepFeeRate: 1,
@ -364,7 +382,7 @@ var stateUpdateTests = []stateUpdateTestCase{
GlobalFeatures: lnwire.NewRawFeatureVector(),
}},
createMsg: &wtwire.CreateSession{
BlobVersion: 0,
BlobType: blob.TypeDefault,
MaxUpdates: 4,
RewardRate: 0,
SweepFeeRate: 1,
@ -393,7 +411,7 @@ var stateUpdateTests = []stateUpdateTestCase{
GlobalFeatures: lnwire.NewRawFeatureVector(),
}},
createMsg: &wtwire.CreateSession{
BlobVersion: 0,
BlobType: blob.TypeDefault,
MaxUpdates: 4,
RewardRate: 0,
SweepFeeRate: 1,
@ -421,7 +439,7 @@ var stateUpdateTests = []stateUpdateTestCase{
GlobalFeatures: lnwire.NewRawFeatureVector(),
}},
createMsg: &wtwire.CreateSession{
BlobVersion: 0,
BlobType: blob.TypeDefault,
MaxUpdates: 3,
RewardRate: 0,
SweepFeeRate: 1,
@ -450,7 +468,7 @@ var stateUpdateTests = []stateUpdateTestCase{
GlobalFeatures: lnwire.NewRawFeatureVector(),
}},
createMsg: &wtwire.CreateSession{
BlobVersion: 0,
BlobType: blob.TypeDefault,
MaxUpdates: 3,
RewardRate: 0,
SweepFeeRate: 1,

11
watchtower/wtwire/create_session.go
View File

@ -4,6 +4,7 @@ import (
"io"
"github.com/lightningnetwork/lnd/lnwallet"
"github.com/lightningnetwork/lnd/watchtower/blob"
)
// CreateSession is sent from a client to tower when to negotiate a session, which
@ -11,9 +12,9 @@ import (
// An update is consumed by uploading an encrypted blob that contains
// information required to sweep a revoked commitment transaction.
type CreateSession struct {
// BlobVersion specifies the blob format that must be used by all
// updates sent under the session key used to negotiate this session.
BlobVersion uint16
// BlobType specifies the blob format that must be used by all updates sent
// under the session key used to negotiate this session.
BlobType blob.Type
// MaxUpdates is the maximum number of updates the watchtower will honor
// for this session.
@ -41,7 +42,7 @@ var _ Message = (*CreateSession)(nil)
// This is part of the wtwire.Message interface.
func (m *CreateSession) Decode(r io.Reader, pver uint32) error {
return ReadElements(r,
&m.BlobVersion,
&m.BlobType,
&m.MaxUpdates,
&m.RewardRate,
&m.SweepFeeRate,
@ -54,7 +55,7 @@ func (m *CreateSession) Decode(r io.Reader, pver uint32) error {
// This is part of the wtwire.Message interface.
func (m *CreateSession) Encode(w io.Writer, pver uint32) error {
return WriteElements(w,
m.BlobVersion,
m.BlobType,
m.MaxUpdates,
m.RewardRate,
m.SweepFeeRate,

4
watchtower/wtwire/create_session_reply.go
View File

@ -25,6 +25,10 @@ const (
// CreateSessionCodeRejectSweepFeeRate the tower rejected the sweep fee
// rate proposed by the client.
CreateSessionCodeRejectSweepFeeRate CreateSessionCode = 63
// CreateSessionCodeRejectBlobType is returned when the tower does not
// support the proposed blob type.
CreateSessionCodeRejectBlobType CreateSessionCode = 64
)
// MaxCreateSessionReplyDataLength is the maximum size of the Data payload

15
watchtower/wtwire/wtwire.go
View File

@ -8,6 +8,7 @@ import (
"github.com/btcsuite/btcd/btcec"
"github.com/btcsuite/btcd/wire"
"github.com/lightningnetwork/lnd/lnwallet"
"github.com/lightningnetwork/lnd/watchtower/blob"
)
// WriteElement is a one-stop shop to write the big endian representation of
@ -30,6 +31,13 @@ func WriteElement(w io.Writer, element interface{}) error {
return err
}
case blob.Type:
var b [2]byte
binary.BigEndian.PutUint16(b[:], uint16(e))
if _, err := w.Write(b[:]); err != nil {
return err
}
case uint32:
var b [4]byte
binary.BigEndian.PutUint32(b[:], e)
@ -127,6 +135,13 @@ func ReadElement(r io.Reader, element interface{}) error {
}
*e = binary.BigEndian.Uint16(b[:])
case *blob.Type:
var b [2]byte
if _, err := io.ReadFull(r, b[:]); err != nil {
return err
}
*e = blob.Type(binary.BigEndian.Uint16(b[:]))
case *uint32:
var b [4]byte
if _, err := io.ReadFull(r, b[:]); err != nil {