prysm-pulse/beacon-chain/core/blocks/attester_slashing.go
terence tsao 8219af46e4
Move slot epoch from core to time pkg (#9714)
* Move slot epoch from core to time pkg

* Fix fuzz

Co-authored-by: prylabs-bulldozer[bot] <58059840+prylabs-bulldozer[bot]@users.noreply.github.com>
2021-09-30 19:00:14 +00:00

143 lines
5.6 KiB
Go

package blocks
import (
"context"
"sort"
"github.com/pkg/errors"
types "github.com/prysmaticlabs/eth2-types"
"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
"github.com/prysmaticlabs/prysm/beacon-chain/core/time"
"github.com/prysmaticlabs/prysm/beacon-chain/state"
"github.com/prysmaticlabs/prysm/config/params"
"github.com/prysmaticlabs/prysm/container/slice"
ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/attestation"
"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/slashings"
"github.com/prysmaticlabs/prysm/runtime/version"
)
// ProcessAttesterSlashings is one of the operations performed
// on each processed beacon block to slash attesters based on
// Casper FFG slashing conditions if any slashable events occurred.
//
// Spec pseudocode definition:
// def process_attester_slashing(state: BeaconState, attester_slashing: AttesterSlashing) -> None:
// attestation_1 = attester_slashing.attestation_1
// attestation_2 = attester_slashing.attestation_2
// assert is_slashable_attestation_data(attestation_1.data, attestation_2.data)
// assert is_valid_indexed_attestation(state, attestation_1)
// assert is_valid_indexed_attestation(state, attestation_2)
//
// slashed_any = False
// indices = set(attestation_1.attesting_indices).intersection(attestation_2.attesting_indices)
// for index in sorted(indices):
// if is_slashable_validator(state.validators[index], get_current_epoch(state)):
// slash_validator(state, index)
// slashed_any = True
// assert slashed_any
func ProcessAttesterSlashings(
ctx context.Context,
beaconState state.BeaconState,
slashings []*ethpb.AttesterSlashing,
slashFunc slashValidatorFunc,
) (state.BeaconState, error) {
for idx, slashing := range slashings {
if err := VerifyAttesterSlashing(ctx, beaconState, slashing); err != nil {
return nil, errors.Wrapf(err, "could not verify attester slashing %d", idx)
}
slashableIndices := slashableAttesterIndices(slashing)
sort.SliceStable(slashableIndices, func(i, j int) bool {
return slashableIndices[i] < slashableIndices[j]
})
currentEpoch := time.SlotToEpoch(beaconState.Slot())
var err error
var slashedAny bool
var val state.ReadOnlyValidator
for _, validatorIndex := range slashableIndices {
val, err = beaconState.ValidatorAtIndexReadOnly(types.ValidatorIndex(validatorIndex))
if err != nil {
return nil, err
}
if helpers.IsSlashableValidator(val.ActivationEpoch(), val.WithdrawableEpoch(), val.Slashed(), currentEpoch) {
cfg := params.BeaconConfig()
slashingQuotient := cfg.MinSlashingPenaltyQuotient
if beaconState.Version() == version.Altair {
slashingQuotient = cfg.MinSlashingPenaltyQuotientAltair
}
beaconState, err = slashFunc(ctx, beaconState, types.ValidatorIndex(validatorIndex), slashingQuotient, cfg.ProposerRewardQuotient)
if err != nil {
return nil, errors.Wrapf(err, "could not slash validator index %d",
validatorIndex)
}
slashedAny = true
}
}
if !slashedAny {
return nil, errors.New("unable to slash any validator despite confirmed attester slashing")
}
}
return beaconState, nil
}
// VerifyAttesterSlashing validates the attestation data in both attestations in the slashing object.
func VerifyAttesterSlashing(ctx context.Context, beaconState state.ReadOnlyBeaconState, slashing *ethpb.AttesterSlashing) error {
if slashing == nil {
return errors.New("nil slashing")
}
if slashing.Attestation_1 == nil || slashing.Attestation_2 == nil {
return errors.New("nil attestation")
}
if slashing.Attestation_1.Data == nil || slashing.Attestation_2.Data == nil {
return errors.New("nil attestation data")
}
att1 := slashing.Attestation_1
att2 := slashing.Attestation_2
data1 := att1.Data
data2 := att2.Data
if !IsSlashableAttestationData(data1, data2) {
return errors.New("attestations are not slashable")
}
if err := VerifyIndexedAttestation(ctx, beaconState, att1); err != nil {
return errors.Wrap(err, "could not validate indexed attestation")
}
if err := VerifyIndexedAttestation(ctx, beaconState, att2); err != nil {
return errors.Wrap(err, "could not validate indexed attestation")
}
return nil
}
// IsSlashableAttestationData verifies a slashing against the Casper Proof of Stake FFG rules.
//
// Spec pseudocode definition:
// def is_slashable_attestation_data(data_1: AttestationData, data_2: AttestationData) -> bool:
// """
// Check if ``data_1`` and ``data_2`` are slashable according to Casper FFG rules.
// """
// return (
// # Double vote
// (data_1 != data_2 and data_1.target.epoch == data_2.target.epoch) or
// # Surround vote
// (data_1.source.epoch < data_2.source.epoch and data_2.target.epoch < data_1.target.epoch)
// )
func IsSlashableAttestationData(data1, data2 *ethpb.AttestationData) bool {
if data1 == nil || data2 == nil || data1.Target == nil || data2.Target == nil || data1.Source == nil || data2.Source == nil {
return false
}
isDoubleVote := !attestation.AttDataIsEqual(data1, data2) && data1.Target.Epoch == data2.Target.Epoch
att1 := &ethpb.IndexedAttestation{Data: data1}
att2 := &ethpb.IndexedAttestation{Data: data2}
// Check if att1 is surrounding att2.
isSurroundVote := slashings.IsSurround(att1, att2)
return isDoubleVote || isSurroundVote
}
func slashableAttesterIndices(slashing *ethpb.AttesterSlashing) []uint64 {
if slashing == nil || slashing.Attestation_1 == nil || slashing.Attestation_2 == nil {
return nil
}
indices1 := slashing.Attestation_1.AttestingIndices
indices2 := slashing.Attestation_2.AttestingIndices
return slice.IntersectionUint64(indices1, indices2)
}