The core protocol of WoopChain
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woop/staking/slash/double-sign.go

525 lines
16 KiB

package slash
import (
"encoding/hex"
"encoding/json"
"math/big"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/rlp"
"github.com/harmony-one/bls/ffi/go/bls"
consensus_sig "github.com/harmony-one/harmony/consensus/signature"
"github.com/harmony-one/harmony/consensus/votepower"
"github.com/harmony-one/harmony/core/state"
"github.com/harmony-one/harmony/core/types"
"github.com/harmony-one/harmony/crypto/hash"
common2 "github.com/harmony-one/harmony/internal/common"
"github.com/harmony-one/harmony/internal/params"
"github.com/harmony-one/harmony/internal/utils"
"github.com/harmony-one/harmony/numeric"
"github.com/harmony-one/harmony/shard"
"github.com/harmony-one/harmony/staking/effective"
staking "github.com/harmony-one/harmony/staking/types"
"github.com/pkg/errors"
)
// invariant assumes snapshot, current can be rlp.EncodeToBytes
func payDebt(
snapshot, current *staking.ValidatorWrapper,
slashDebt, payment *big.Int,
slashDiff *Application,
) error {
utils.Logger().Info().
RawJSON("snapshot", []byte(snapshot.String())).
RawJSON("current", []byte(current.String())).
Uint64("slash-debt", slashDebt.Uint64()).
Uint64("payment", payment.Uint64()).
RawJSON("slash-track", []byte(slashDiff.String())).
Msg("slash debt payment before application")
slashDiff.TotalSlashed.Add(slashDiff.TotalSlashed, payment)
slashDebt.Sub(slashDebt, payment)
if slashDebt.Cmp(common.Big0) == -1 {
x1, _ := rlp.EncodeToBytes(snapshot)
x2, _ := rlp.EncodeToBytes(current)
utils.Logger().Info().
Str("snapshot-rlp", hex.EncodeToString(x1)).
Str("current-rlp", hex.EncodeToString(x2)).
Msg("slashdebt balance cannot go below zero")
return errSlashDebtCannotBeNegative
}
return nil
}
// Moment ..
type Moment struct {
Epoch *big.Int `json:"epoch"`
ShardID uint32 `json:"shard-id"`
Height uint64 `json:"height"`
ViewID uint64 `json:"view-id"`
}
// Evidence ..
type Evidence struct {
Moment
ConflictingVotes
Offender common.Address `json:"offender"`
}
// ConflictingVotes ..
type ConflictingVotes struct {
FirstVote Vote `json:"first-vote"`
SecondVote Vote `json:"second-vote"`
}
// Vote is the vote of the double signer
type Vote struct {
SignerPubKey shard.BLSPublicKey `json:"bls-public-key"`
BlockHeaderHash common.Hash `json:"block-header-hash"`
Signature []byte `json:"bls-signature"`
}
// Record is an proof of a slashing made by a witness of a double-signing event
type Record struct {
// the reporter who will get rewarded
Evidence Evidence `json:"evidence"`
Reporter common.Address `json:"reporter"`
}
// Application tracks the slash application to state
type Application struct {
TotalSlashed *big.Int `json:"total-slashed"`
TotalSnitchReward *big.Int `json:"total-snitch-reward"`
}
func (a *Application) String() string {
s, _ := json.Marshal(a)
return string(s)
}
// MarshalJSON ..
func (e Evidence) MarshalJSON() ([]byte, error) {
return json.Marshal(struct {
Moment
ConflictingVotes
}{e.Moment, e.ConflictingVotes})
}
// Records ..
type Records []Record
func (r Records) String() string {
s, _ := json.Marshal(r)
return string(s)
}
var (
errBallotSignerKeysNotSame = errors.New("conflicting ballots must have same signer key")
errReporterAndOffenderSame = errors.New("reporter and offender cannot be same")
errAlreadyBannedValidator = errors.New("cannot slash on already banned validator")
errSignerKeyNotRightSize = errors.New("bls keys from slash candidate not right side")
errSlashFromFutureEpoch = errors.New("cannot have slash from future epoch")
errSlashBlockNoConflict = errors.New("cannot slash for signing on non-conflicting blocks")
)
// MarshalJSON ..
func (r Record) MarshalJSON() ([]byte, error) {
reporter, offender :=
common2.MustAddressToBech32(r.Reporter),
common2.MustAddressToBech32(r.Evidence.Offender)
return json.Marshal(struct {
Evidence Evidence `json:"evidence"`
Beneficiary string `json:"beneficiary"`
AddressForBLSKey string `json:"offender"`
}{r.Evidence, reporter, offender})
}
func (e Evidence) String() string {
s, _ := json.Marshal(e)
return string(s)
}
func (r Record) String() string {
s, _ := json.Marshal(r)
return string(s)
}
// CommitteeReader ..
type CommitteeReader interface {
Config() *params.ChainConfig
ReadShardState(epoch *big.Int) (*shard.State, error)
CurrentBlock() *types.Block
}
// Verify checks that the slash is valid
func Verify(
chain CommitteeReader,
state *state.DB,
candidate *Record,
) error {
wrapper, err := state.ValidatorWrapper(candidate.Evidence.Offender)
if err != nil {
return err
}
if wrapper.Status == effective.Banned {
return errAlreadyBannedValidator
}
if candidate.Evidence.Offender == candidate.Reporter {
return errReporterAndOffenderSame
}
first, second :=
candidate.Evidence.FirstVote,
candidate.Evidence.SecondVote
k1, k2 := len(first.SignerPubKey), len(second.SignerPubKey)
if k1 != shard.PublicKeySizeInBytes ||
k2 != shard.PublicKeySizeInBytes {
return errors.Wrapf(
errSignerKeyNotRightSize, "cast key %d double-signed key %d", k1, k2,
)
}
if first.BlockHeaderHash == second.BlockHeaderHash {
return errors.Wrapf(errSlashBlockNoConflict, "first %v+ second %v+", first, second)
}
if shard.CompareBLSPublicKey(first.SignerPubKey, second.SignerPubKey) != 0 {
k1, k2 := first.SignerPubKey.Hex(), second.SignerPubKey.Hex()
return errors.Wrapf(
errBallotSignerKeysNotSame, "%s %s", k1, k2,
)
}
currentEpoch := chain.CurrentBlock().Epoch()
// the slash can't come from the future (shard chain's epoch can't be larger than beacon chain's)
if candidate.Evidence.Epoch.Cmp(currentEpoch) == 1 {
return errors.Wrapf(
errSlashFromFutureEpoch, "current-epoch %v", currentEpoch,
)
}
superCommittee, err := chain.ReadShardState(candidate.Evidence.Epoch)
if err != nil {
return err
}
subCommittee, err := superCommittee.FindCommitteeByID(
candidate.Evidence.ShardID,
)
if err != nil {
return errors.Wrapf(
err, "given shardID %d", candidate.Evidence.ShardID,
)
}
if addr, err := subCommittee.AddressForBLSKey(
second.SignerPubKey,
); err != nil {
return err
} else if *addr != candidate.Evidence.Offender {
return errors.Errorf("offender address (%x) does not match the signer's address (%x)", candidate.Evidence.Offender, addr)
}
// last ditch check
if hash.FromRLPNew256(
candidate.Evidence.FirstVote,
) == hash.FromRLPNew256(
candidate.Evidence.SecondVote,
) {
return errors.Wrapf(
errBallotsNotDiff,
"%s %s",
candidate.Evidence.FirstVote.SignerPubKey.Hex(),
candidate.Evidence.SecondVote.SignerPubKey.Hex(),
)
}
for _, ballot := range [...]Vote{
candidate.Evidence.FirstVote,
candidate.Evidence.SecondVote,
} {
// now the only real assurance, cryptography
signature := &bls.Sign{}
publicKey := &bls.PublicKey{}
if err := signature.Deserialize(ballot.Signature); err != nil {
return err
}
if err := ballot.SignerPubKey.ToLibBLSPublicKey(publicKey); err != nil {
return err
}
// slash verification only happens in staking era, therefore want commit payload for staking epoch
commitPayload := consensus_sig.ConstructCommitPayload(chain,
chain.Config().StakingEpoch, ballot.BlockHeaderHash, candidate.Evidence.Height, candidate.Evidence.ViewID)
utils.Logger().Debug().
Uint64("epoch", chain.Config().StakingEpoch.Uint64()).
Uint64("block-number", candidate.Evidence.Height).
Uint64("view-id", candidate.Evidence.ViewID).
Msgf("[COMMIT-PAYLOAD] doubleSignVerify %v", hex.EncodeToString(commitPayload))
if !signature.VerifyHash(publicKey, commitPayload) {
return errFailVerifySlash
}
}
return nil
}
var (
errSlashDebtCannotBeNegative = errors.New("slash debt cannot be negative")
errValidatorNotFoundDuringSlash = errors.New("validator not found")
errFailVerifySlash = errors.New("could not verify bls key signature on slash")
errBallotsNotDiff = errors.New("ballots submitted must be different")
oneDoubleSignerRate = numeric.MustNewDecFromStr("0.02")
)
// applySlashRate returns (amountPostSlash, amountOfReduction, amountOfReduction / 2)
func applySlashRate(amount *big.Int, rate numeric.Dec) *big.Int {
return numeric.NewDecFromBigInt(
amount,
).Mul(rate).TruncateInt()
}
// Hash is a New256 hash of an RLP encoded Record
func (r Record) Hash() common.Hash {
return hash.FromRLPNew256(r)
}
// SetDifference returns all the records that are in ys but not in r
func (r Records) SetDifference(ys Records) Records {
diff, set := Records{}, map[common.Hash]struct{}{}
for i := range r {
h := r[i].Hash()
if _, ok := set[h]; !ok {
set[h] = struct{}{}
}
}
for i := range ys {
h := ys[i].Hash()
if _, ok := set[h]; !ok {
diff = append(diff, ys[i])
}
}
return diff
}
func payDownAsMuchAsCan(
snapshot, current *staking.ValidatorWrapper,
slashDebt, nowAmt *big.Int,
slashDiff *Application,
) error {
if nowAmt.Cmp(common.Big0) == 1 && slashDebt.Cmp(common.Big0) == 1 {
// 0.50_amount > 0.06_debt => slash == 0.0, nowAmt == 0.44
if nowAmt.Cmp(slashDebt) >= 0 {
nowAmt.Sub(nowAmt, slashDebt)
if err := payDebt(
snapshot, current, slashDebt, slashDebt, slashDiff,
); err != nil {
return err
}
} else {
// 0.50_amount < 2.4_debt =>, slash == 1.9, nowAmt == 0.0
if err := payDebt(
snapshot, current, slashDebt, nowAmt, slashDiff,
); err != nil {
return err
}
nowAmt.Sub(nowAmt, nowAmt)
}
}
return nil
}
func delegatorSlashApply(
snapshot, current *staking.ValidatorWrapper,
rate numeric.Dec,
state *state.DB,
reporter common.Address,
doubleSignEpoch *big.Int,
slashTrack *Application,
) error {
for _, delegationSnapshot := range snapshot.Delegations {
slashDebt := applySlashRate(delegationSnapshot.Amount, rate)
slashDiff := &Application{big.NewInt(0), big.NewInt(0)}
snapshotAddr := delegationSnapshot.DelegatorAddress
for i := range current.Delegations {
delegationNow := current.Delegations[i]
if nowAmt := delegationNow.Amount; delegationNow.DelegatorAddress == snapshotAddr {
utils.Logger().Info().
RawJSON("delegation-snapshot", []byte(delegationSnapshot.String())).
RawJSON("delegation-current", []byte(delegationNow.String())).
Uint64("initial-slash-debt", slashDebt.Uint64()).
Str("rate", rate.String()).
Msg("attempt to apply slashing based on snapshot amount to current state")
// Current delegation has some money and slashdebt is still not paid off
// so contribute as much as can with current delegation amount
if err := payDownAsMuchAsCan(
snapshot, current, slashDebt, nowAmt, slashDiff,
); err != nil {
return err
}
// NOTE Assume did as much as could above, now check the undelegations
for i := range delegationNow.Undelegations {
undelegate := delegationNow.Undelegations[i]
// the epoch matters, only those undelegation
// such that epoch>= doubleSignEpoch should be slashable
if undelegate.Epoch.Cmp(doubleSignEpoch) >= 0 {
if slashDebt.Cmp(common.Big0) <= 0 {
utils.Logger().Info().
RawJSON("delegation-snapshot", []byte(delegationSnapshot.String())).
RawJSON("delegation-current", []byte(delegationNow.String())).
Msg("paid off the slash debt")
break
}
nowAmt := undelegate.Amount
if err := payDownAsMuchAsCan(
snapshot, current, slashDebt, nowAmt, slashDiff,
); err != nil {
return err
}
if nowAmt.Cmp(common.Big0) == 0 {
utils.Logger().Info().
RawJSON("delegation-snapshot", []byte(delegationSnapshot.String())).
RawJSON("delegation-current", []byte(delegationNow.String())).
Msg("delegation amount after paying slash debt is 0")
}
}
}
// if we still have a slashdebt
// even after taking away from delegation amount
// and even after taking away from undelegate,
// then we need to take from their pending rewards
if slashDebt.Cmp(common.Big0) == 1 {
nowAmt := delegationNow.Reward
utils.Logger().Info().
RawJSON("delegation-snapshot", []byte(delegationSnapshot.String())).
RawJSON("delegation-current", []byte(delegationNow.String())).
Uint64("slash-debt", slashDebt.Uint64()).
Uint64("now-amount-reward", nowAmt.Uint64()).
Msg("needed to dig into reward to pay off slash debt")
if err := payDownAsMuchAsCan(
snapshot, current, slashDebt, nowAmt, slashDiff,
); err != nil {
return err
}
}
// NOTE only need to pay snitch here,
// they only get half of what was actually dispersed
halfOfSlashDebt := new(big.Int).Div(slashDiff.TotalSlashed, common.Big2)
slashDiff.TotalSnitchReward.Add(slashDiff.TotalSnitchReward, halfOfSlashDebt)
utils.Logger().Info().
RawJSON("delegation-snapshot", []byte(delegationSnapshot.String())).
RawJSON("delegation-current", []byte(delegationNow.String())).
Uint64("reporter-reward", halfOfSlashDebt.Uint64()).
RawJSON("application", []byte(slashDiff.String())).
Msg("completed an application of slashing")
state.AddBalance(reporter, halfOfSlashDebt)
slashTrack.TotalSnitchReward.Add(
slashTrack.TotalSnitchReward, slashDiff.TotalSnitchReward,
)
slashTrack.TotalSlashed.Add(
slashTrack.TotalSlashed, slashDiff.TotalSlashed,
)
}
}
// after the loops, paid off as much as could
if slashDebt.Cmp(common.Big0) == -1 {
x1, _ := rlp.EncodeToBytes(snapshot)
x2, _ := rlp.EncodeToBytes(current)
utils.Logger().Error().Str("slash-rate", rate.String()).
Str("snapshot-rlp", hex.EncodeToString(x1)).
Str("current-rlp", hex.EncodeToString(x2)).
Msg("slash debt not paid off")
return errors.Wrapf(errSlashDebtCannotBeNegative, "amt %v", slashDebt)
}
}
return nil
}
// Apply ..
func Apply(
chain staking.ValidatorSnapshotReader, state *state.DB,
slashes Records, rate numeric.Dec,
) (*Application, error) {
slashDiff := &Application{big.NewInt(0), big.NewInt(0)}
for _, slash := range slashes {
snapshot, err := chain.ReadValidatorSnapshotAtEpoch(
slash.Evidence.Epoch,
slash.Evidence.Offender,
)
if err != nil {
return nil, errors.Errorf(
"could not find validator %s",
common2.MustAddressToBech32(slash.Evidence.Offender),
)
}
current, err := state.ValidatorWrapper(slash.Evidence.Offender)
if err != nil {
return nil, errors.Wrapf(
errValidatorNotFoundDuringSlash, " %s ", err.Error(),
)
}
// NOTE invariant: first delegation is the validators own
// stake, rest are external delegations.
// Bottom line: everyone will be slashed under the same rule.
if err := delegatorSlashApply(
snapshot.Validator, current, rate, state,
slash.Reporter, slash.Evidence.Epoch, slashDiff,
); err != nil {
return nil, err
}
// finally, kick them off forever
current.Status = effective.Banned
utils.Logger().Info().
RawJSON("delegation-current", []byte(current.String())).
RawJSON("slash", []byte(slash.String())).
Msg("about to update staking info for a validator after a slash")
if err := current.SanityCheck(staking.DoNotEnforceMaxBLS); err != nil {
return nil, err
}
}
return slashDiff, nil
}
// IsBanned ..
func IsBanned(wrapper *staking.ValidatorWrapper) bool {
return wrapper.Status == effective.Banned
}
// Rate is the slashing % rate
func Rate(votingPower *votepower.Roster, records Records) numeric.Dec {
rate := numeric.ZeroDec()
for i := range records {
key := records[i].Evidence.SecondVote.SignerPubKey
if card, exists := votingPower.Voters[key]; exists {
rate = rate.Add(card.GroupPercent)
} else {
utils.Logger().Debug().
RawJSON("roster", []byte(votingPower.String())).
RawJSON("double-sign-record", []byte(records[i].String())).
Msg("did not have offenders voter card in roster as expected")
}
}
if rate.LT(oneDoubleSignerRate) {
rate = oneDoubleSignerRate
}
return rate
}