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tendermint/types/evidence.go

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package types
import (
"bytes"
"errors"
"fmt"
"strings"
"time"
"github.com/tendermint/tendermint/crypto/tmhash"
tmmath "github.com/tendermint/tendermint/libs/math"
amino "github.com/tendermint/go-amino"
"github.com/tendermint/tendermint/crypto"
"github.com/tendermint/tendermint/crypto/merkle"
)
const (
// MaxEvidenceBytes is a maximum size of any evidence (including amino overhead).
MaxEvidenceBytes int64 = 444
// An invalid field in the header from LunaticValidatorEvidence.
// Must be a function of the ABCI application state.
ValidatorsHashField = "ValidatorsHash"
NextValidatorsHashField = "NextValidatorsHash"
ConsensusHashField = "ConsensusHash"
AppHashField = "AppHash"
LastResultsHashField = "LastResultsHash"
)
// ErrEvidenceInvalid wraps a piece of evidence and the error denoting how or why it is invalid.
type ErrEvidenceInvalid struct {
Evidence Evidence
ErrorValue error
}
// NewErrEvidenceInvalid returns a new EvidenceInvalid with the given err.
func NewErrEvidenceInvalid(ev Evidence, err error) *ErrEvidenceInvalid {
return &ErrEvidenceInvalid{ev, err}
}
// Error returns a string representation of the error.
func (err *ErrEvidenceInvalid) Error() string {
return fmt.Sprintf("Invalid evidence: %v. Evidence: %v", err.ErrorValue, err.Evidence)
}
// ErrEvidenceOverflow is for when there is too much evidence in a block.
type ErrEvidenceOverflow struct {
MaxNum int
GotNum int
}
// NewErrEvidenceOverflow returns a new ErrEvidenceOverflow where got > max.
func NewErrEvidenceOverflow(max, got int) *ErrEvidenceOverflow {
return &ErrEvidenceOverflow{max, got}
}
// Error returns a string representation of the error.
func (err *ErrEvidenceOverflow) Error() string {
return fmt.Sprintf("Too much evidence: Max %d, got %d", err.MaxNum, err.GotNum)
}
//-------------------------------------------
// Evidence represents any provable malicious activity by a validator.
type Evidence interface {
Height() int64 // height of the equivocation
Time() time.Time // time of the equivocation
Address() []byte // address of the equivocating validator
Bytes() []byte // bytes which comprise the evidence
Hash() []byte // hash of the evidence
Verify(chainID string, pubKey crypto.PubKey) error // verify the evidence
Equal(Evidence) bool // check equality of evidence
ValidateBasic() error
String() string
}
type CompositeEvidence interface {
VerifyComposite(committedHeader *Header, valSet *ValidatorSet) error
Split(committedHeader *Header, valSet *ValidatorSet, valToLastHeight map[string]int64) []Evidence
}
func RegisterEvidences(cdc *amino.Codec) {
cdc.RegisterInterface((*Evidence)(nil), nil)
cdc.RegisterConcrete(&DuplicateVoteEvidence{}, "tendermint/DuplicateVoteEvidence", nil)
cdc.RegisterConcrete(&ConflictingHeadersEvidence{}, "tendermint/ConflictingHeadersEvidence", nil)
cdc.RegisterConcrete(&PhantomValidatorEvidence{}, "tendermint/PhantomValidatorEvidence", nil)
cdc.RegisterConcrete(&LunaticValidatorEvidence{}, "tendermint/LunaticValidatorEvidence", nil)
cdc.RegisterConcrete(&PotentialAmnesiaEvidence{}, "tendermint/PotentialAmnesiaEvidence", nil)
}
func RegisterMockEvidences(cdc *amino.Codec) {
cdc.RegisterConcrete(MockEvidence{}, "tendermint/MockEvidence", nil)
cdc.RegisterConcrete(MockRandomEvidence{}, "tendermint/MockRandomEvidence", nil)
}
//-------------------------------------------
// DuplicateVoteEvidence contains evidence a validator signed two conflicting
// votes.
type DuplicateVoteEvidence struct {
VoteA *Vote
VoteB *Vote
}
var _ Evidence = &DuplicateVoteEvidence{}
// NewDuplicateVoteEvidence creates DuplicateVoteEvidence with right ordering given
// two conflicting votes. If one of the votes is nil, evidence returned is nil as well
func NewDuplicateVoteEvidence(vote1 *Vote, vote2 *Vote) *DuplicateVoteEvidence {
var voteA, voteB *Vote
if vote1 == nil || vote2 == nil {
return nil
}
if strings.Compare(vote1.BlockID.Key(), vote2.BlockID.Key()) == -1 {
voteA = vote1
voteB = vote2
} else {
voteA = vote2
voteB = vote1
}
return &DuplicateVoteEvidence{
VoteA: voteA,
VoteB: voteB,
}
}
// String returns a string representation of the evidence.
func (dve *DuplicateVoteEvidence) String() string {
return fmt.Sprintf("DuplicateVoteEvidence{VoteA: %v, VoteB: %v}", dve.VoteA, dve.VoteB)
}
// Height returns the height this evidence refers to.
func (dve *DuplicateVoteEvidence) Height() int64 {
return dve.VoteA.Height
}
// Time returns the time the evidence was created.
func (dve *DuplicateVoteEvidence) Time() time.Time {
return dve.VoteA.Timestamp
}
// Address returns the address of the validator.
func (dve *DuplicateVoteEvidence) Address() []byte {
return dve.VoteA.ValidatorAddress
}
// Hash returns the hash of the evidence.
func (dve *DuplicateVoteEvidence) Bytes() []byte {
return cdcEncode(dve)
}
// Hash returns the hash of the evidence.
func (dve *DuplicateVoteEvidence) Hash() []byte {
return tmhash.Sum(cdcEncode(dve))
}
// Verify returns an error if the two votes aren't conflicting.
//
// To be conflicting, they must be from the same validator, for the same H/R/S,
// but for different blocks.
func (dve *DuplicateVoteEvidence) Verify(chainID string, pubKey crypto.PubKey) error {
// H/R/S must be the same
if dve.VoteA.Height != dve.VoteB.Height ||
dve.VoteA.Round != dve.VoteB.Round ||
dve.VoteA.Type != dve.VoteB.Type {
return fmt.Errorf("h/r/s does not match: %d/%d/%v vs %d/%d/%v",
dve.VoteA.Height, dve.VoteA.Round, dve.VoteA.Type,
dve.VoteB.Height, dve.VoteB.Round, dve.VoteB.Type)
}
// Address must be the same
if !bytes.Equal(dve.VoteA.ValidatorAddress, dve.VoteB.ValidatorAddress) {
return fmt.Errorf("validator addresses do not match: %X vs %X",
dve.VoteA.ValidatorAddress,
dve.VoteB.ValidatorAddress,
)
}
// Index must be the same
if dve.VoteA.ValidatorIndex != dve.VoteB.ValidatorIndex {
return fmt.Errorf(
"validator indices do not match: %d and %d",
dve.VoteA.ValidatorIndex,
dve.VoteB.ValidatorIndex,
)
}
// BlockIDs must be different
if dve.VoteA.BlockID.Equals(dve.VoteB.BlockID) {
return fmt.Errorf(
"block IDs are the same (%v) - not a real duplicate vote",
dve.VoteA.BlockID,
)
}
// pubkey must match address (this should already be true, sanity check)
addr := dve.VoteA.ValidatorAddress
if !bytes.Equal(pubKey.Address(), addr) {
return fmt.Errorf("address (%X) doesn't match pubkey (%v - %X)",
addr, pubKey, pubKey.Address())
}
// Signatures must be valid
if !pubKey.VerifyBytes(dve.VoteA.SignBytes(chainID), dve.VoteA.Signature) {
return fmt.Errorf("verifying VoteA: %w", ErrVoteInvalidSignature)
}
if !pubKey.VerifyBytes(dve.VoteB.SignBytes(chainID), dve.VoteB.Signature) {
return fmt.Errorf("verifying VoteB: %w", ErrVoteInvalidSignature)
}
return nil
}
// Equal checks if two pieces of evidence are equal.
func (dve *DuplicateVoteEvidence) Equal(ev Evidence) bool {
if _, ok := ev.(*DuplicateVoteEvidence); !ok {
return false
}
// just check their hashes
dveHash := tmhash.Sum(cdcEncode(dve))
evHash := tmhash.Sum(cdcEncode(ev))
return bytes.Equal(dveHash, evHash)
}
// ValidateBasic performs basic validation.
func (dve *DuplicateVoteEvidence) ValidateBasic() error {
if dve.VoteA == nil || dve.VoteB == nil {
return fmt.Errorf("one or both of the votes are empty %v, %v", dve.VoteA, dve.VoteB)
}
if err := dve.VoteA.ValidateBasic(); err != nil {
return fmt.Errorf("invalid VoteA: %w", err)
}
if err := dve.VoteB.ValidateBasic(); err != nil {
return fmt.Errorf("invalid VoteB: %w", err)
}
// Enforce Votes are lexicographically sorted on blockID
if strings.Compare(dve.VoteA.BlockID.Key(), dve.VoteB.BlockID.Key()) >= 0 {
return errors.New("duplicate votes in invalid order")
}
return nil
}
//-------------------------------------------
// EvidenceList is a list of Evidence. Evidences is not a word.
type EvidenceList []Evidence
// Hash returns the simple merkle root hash of the EvidenceList.
func (evl EvidenceList) Hash() []byte {
// These allocations are required because Evidence is not of type Bytes, and
// golang slices can't be typed cast. This shouldn't be a performance problem since
// the Evidence size is capped.
evidenceBzs := make([][]byte, len(evl))
for i := 0; i < len(evl); i++ {
evidenceBzs[i] = evl[i].Bytes()
}
return merkle.SimpleHashFromByteSlices(evidenceBzs)
}
func (evl EvidenceList) String() string {
s := ""
for _, e := range evl {
s += fmt.Sprintf("%s\t\t", e)
}
return s
}
// Has returns true if the evidence is in the EvidenceList.
func (evl EvidenceList) Has(evidence Evidence) bool {
for _, ev := range evl {
if ev.Equal(evidence) {
return true
}
}
return false
}
//-------------------------------------------
// ConflictingHeadersEvidence is primarily used by the light client when it
// observes two conflicting headers, both having 1/3+ of the voting power of
// the currently trusted validator set.
type ConflictingHeadersEvidence struct {
H1 *SignedHeader `json:"h_1"`
H2 *SignedHeader `json:"h_2"`
}
var _ Evidence = &ConflictingHeadersEvidence{}
var _ CompositeEvidence = &ConflictingHeadersEvidence{}
var _ Evidence = ConflictingHeadersEvidence{}
var _ CompositeEvidence = ConflictingHeadersEvidence{}
// Split breaks up eviddence into smaller chunks (one per validator except for
// PotentialAmnesiaEvidence): PhantomValidatorEvidence,
// LunaticValidatorEvidence, DuplicateVoteEvidence and
// PotentialAmnesiaEvidence.
//
// committedHeader - header at height H1.Height == H2.Height
// valSet - validator set at height H1.Height == H2.Height
// valToLastHeight - map between active validators and respective last heights
func (ev ConflictingHeadersEvidence) Split(committedHeader *Header, valSet *ValidatorSet,
valToLastHeight map[string]int64) []Evidence {
evList := make([]Evidence, 0)
var alternativeHeader *SignedHeader
if bytes.Equal(committedHeader.Hash(), ev.H1.Hash()) {
alternativeHeader = ev.H2
} else {
alternativeHeader = ev.H1
}
// If there are signers(alternativeHeader) that are not part of
// validators(committedHeader), they misbehaved as they are signing protocol
// messages in heights they are not validators => immediately slashable
// (#F4).
for i, sig := range alternativeHeader.Commit.Signatures {
if sig.Absent() {
continue
}
lastHeightValidatorWasInSet, ok := valToLastHeight[string(sig.ValidatorAddress)]
if !ok {
continue
}
if !valSet.HasAddress(sig.ValidatorAddress) {
evList = append(evList, &PhantomValidatorEvidence{
Header: alternativeHeader.Header,
Vote: alternativeHeader.Commit.GetVote(i),
LastHeightValidatorWasInSet: lastHeightValidatorWasInSet,
})
}
}
// If ValidatorsHash, NextValidatorsHash, ConsensusHash, AppHash, and
// LastResultsHash in alternativeHeader are different (incorrect application
// state transition), then it is a lunatic misbehavior => immediately
// slashable (#F5).
var invalidField string
switch {
case !bytes.Equal(committedHeader.ValidatorsHash, alternativeHeader.ValidatorsHash):
invalidField = "ValidatorsHash"
case !bytes.Equal(committedHeader.NextValidatorsHash, alternativeHeader.NextValidatorsHash):
invalidField = "NextValidatorsHash"
case !bytes.Equal(committedHeader.ConsensusHash, alternativeHeader.ConsensusHash):
invalidField = "ConsensusHash"
case !bytes.Equal(committedHeader.AppHash, alternativeHeader.AppHash):
invalidField = "AppHash"
case !bytes.Equal(committedHeader.LastResultsHash, alternativeHeader.LastResultsHash):
invalidField = "LastResultsHash"
}
if invalidField != "" {
for i, sig := range alternativeHeader.Commit.Signatures {
if sig.Absent() {
continue
}
evList = append(evList, &LunaticValidatorEvidence{
Header: alternativeHeader.Header,
Vote: alternativeHeader.Commit.GetVote(i),
InvalidHeaderField: invalidField,
})
}
return evList
}
// Use the fact that signatures are sorted by ValidatorAddress.
var (
i = 0
j = 0
)
OUTER_LOOP:
for i < len(ev.H1.Commit.Signatures) {
sigA := ev.H1.Commit.Signatures[i]
if sigA.Absent() {
i++
continue
}
// FIXME: Replace with HasAddress once DuplicateVoteEvidence#PubKey is
// removed.
_, val := valSet.GetByAddress(sigA.ValidatorAddress)
if val == nil {
i++
continue
}
for j < len(ev.H2.Commit.Signatures) {
sigB := ev.H2.Commit.Signatures[j]
if sigB.Absent() {
j++
continue
}
switch bytes.Compare(sigA.ValidatorAddress, sigB.ValidatorAddress) {
case 0:
// if H1.Round == H2.Round, and some signers signed different precommit
// messages in both commits, then it is an equivocation misbehavior =>
// immediately slashable (#F1).
if ev.H1.Commit.Round == ev.H2.Commit.Round {
evList = append(evList, &DuplicateVoteEvidence{
VoteA: ev.H1.Commit.GetVote(i),
VoteB: ev.H2.Commit.GetVote(j),
})
} else {
// if H1.Round != H2.Round we need to run full detection procedure => not
// immediately slashable.
evList = append(evList, &PotentialAmnesiaEvidence{
VoteA: ev.H1.Commit.GetVote(i),
VoteB: ev.H2.Commit.GetVote(j),
})
}
i++
j++
continue OUTER_LOOP
case 1:
i++
continue OUTER_LOOP
case -1:
j++
}
}
}
return evList
}
func (ev ConflictingHeadersEvidence) Height() int64 { return ev.H1.Height }
// XXX: this is not the time of equivocation
func (ev ConflictingHeadersEvidence) Time() time.Time { return ev.H1.Time }
func (ev ConflictingHeadersEvidence) Address() []byte {
panic("use ConflictingHeadersEvidence#Split to split evidence into individual pieces")
}
func (ev ConflictingHeadersEvidence) Bytes() []byte {
return cdcEncode(ev)
}
func (ev ConflictingHeadersEvidence) Hash() []byte {
bz := make([]byte, tmhash.Size*2)
copy(bz[:tmhash.Size-1], ev.H1.Hash().Bytes())
copy(bz[tmhash.Size:], ev.H2.Hash().Bytes())
return tmhash.Sum(bz)
}
func (ev ConflictingHeadersEvidence) Verify(chainID string, _ crypto.PubKey) error {
panic("use ConflictingHeadersEvidence#VerifyComposite to verify composite evidence")
}
// VerifyComposite verifies that both headers belong to the same chain, same
// height and signed by 1/3+ of validators at height H1.Height == H2.Height.
func (ev ConflictingHeadersEvidence) VerifyComposite(committedHeader *Header, valSet *ValidatorSet) error {
var alternativeHeader *SignedHeader
switch {
case bytes.Equal(committedHeader.Hash(), ev.H1.Hash()):
alternativeHeader = ev.H2
case bytes.Equal(committedHeader.Hash(), ev.H2.Hash()):
alternativeHeader = ev.H1
default:
return errors.New("none of the headers are committed from this node's perspective")
}
// ChainID must be the same
if committedHeader.ChainID != alternativeHeader.ChainID {
return errors.New("alt header is from a different chain")
}
// Height must be the same
if committedHeader.Height != alternativeHeader.Height {
return errors.New("alt header is from a different height")
}
// Limit the number of signatures to avoid DoS attacks where a header
// contains too many signatures.
//
// Validator set size = 100 [node]
// Max validator set size = 100 * 2 = 200 [fork?]
maxNumValidators := valSet.Size() * 2
if len(alternativeHeader.Commit.Signatures) > maxNumValidators {
return fmt.Errorf("alt commit contains too many signatures: %d, expected no more than %d",
len(alternativeHeader.Commit.Signatures),
maxNumValidators)
}
// Header must be signed by at least 1/3+ of voting power of currently
// trusted validator set.
if err := valSet.VerifyCommitTrusting(
alternativeHeader.ChainID,
alternativeHeader.Commit,
tmmath.Fraction{Numerator: 1, Denominator: 3}); err != nil {
return fmt.Errorf("alt header does not have 1/3+ of voting power of our validator set: %w", err)
}
return nil
}
func (ev ConflictingHeadersEvidence) Equal(ev2 Evidence) bool {
switch e2 := ev2.(type) {
case ConflictingHeadersEvidence:
return bytes.Equal(ev.H1.Hash(), e2.H1.Hash()) && bytes.Equal(ev.H2.Hash(), e2.H2.Hash())
case *ConflictingHeadersEvidence:
return bytes.Equal(ev.H1.Hash(), e2.H1.Hash()) && bytes.Equal(ev.H2.Hash(), e2.H2.Hash())
default:
return false
}
}
func (ev ConflictingHeadersEvidence) ValidateBasic() error {
if ev.H1 == nil {
return errors.New("first header is missing")
}
if ev.H2 == nil {
return errors.New("second header is missing")
}
if err := ev.H1.ValidateBasic(ev.H1.ChainID); err != nil {
return fmt.Errorf("h1: %w", err)
}
if err := ev.H2.ValidateBasic(ev.H2.ChainID); err != nil {
return fmt.Errorf("h2: %w", err)
}
return nil
}
func (ev ConflictingHeadersEvidence) String() string {
return fmt.Sprintf("ConflictingHeadersEvidence{H1: %d#%X, H2: %d#%X}",
ev.H1.Height, ev.H1.Hash(),
ev.H2.Height, ev.H2.Hash())
}
//-------------------------------------------
type PhantomValidatorEvidence struct {
Header *Header `json:"header"`
Vote *Vote `json:"vote"`
LastHeightValidatorWasInSet int64 `json:"last_height_validator_was_in_set"`
}
var _ Evidence = &PhantomValidatorEvidence{}
var _ Evidence = PhantomValidatorEvidence{}
func (e PhantomValidatorEvidence) Height() int64 {
return e.Header.Height
}
func (e PhantomValidatorEvidence) Time() time.Time {
return e.Header.Time
}
func (e PhantomValidatorEvidence) Address() []byte {
return e.Vote.ValidatorAddress
}
func (e PhantomValidatorEvidence) Hash() []byte {
bz := make([]byte, tmhash.Size+crypto.AddressSize)
copy(bz[:tmhash.Size-1], e.Header.Hash().Bytes())
copy(bz[tmhash.Size:], e.Vote.ValidatorAddress.Bytes())
return tmhash.Sum(bz)
}
func (e PhantomValidatorEvidence) Bytes() []byte {
return cdcEncode(e)
}
func (e PhantomValidatorEvidence) Verify(chainID string, pubKey crypto.PubKey) error {
// chainID must be the same
if chainID != e.Header.ChainID {
return fmt.Errorf("chainID do not match: %s vs %s",
chainID,
e.Header.ChainID,
)
}
if !pubKey.VerifyBytes(e.Vote.SignBytes(chainID), e.Vote.Signature) {
return errors.New("invalid signature")
}
return nil
}
func (e PhantomValidatorEvidence) Equal(ev Evidence) bool {
switch e2 := ev.(type) {
case PhantomValidatorEvidence:
return bytes.Equal(e.Header.Hash(), e2.Header.Hash()) &&
bytes.Equal(e.Vote.ValidatorAddress, e2.Vote.ValidatorAddress)
case *PhantomValidatorEvidence:
return bytes.Equal(e.Header.Hash(), e2.Header.Hash()) &&
bytes.Equal(e.Vote.ValidatorAddress, e2.Vote.ValidatorAddress)
default:
return false
}
}
func (e PhantomValidatorEvidence) ValidateBasic() error {
if e.Header == nil {
return errors.New("empty header")
}
if e.Vote == nil {
return errors.New("empty vote")
}
if err := e.Header.ValidateBasic(); err != nil {
return fmt.Errorf("invalid header: %v", err)
}
if err := e.Vote.ValidateBasic(); err != nil {
return fmt.Errorf("invalid signature: %v", err)
}
if !e.Vote.BlockID.IsComplete() {
return errors.New("expected vote for block")
}
if e.Header.Height != e.Vote.Height {
return fmt.Errorf("header and vote have different heights: %d vs %d",
e.Header.Height,
e.Vote.Height,
)
}
if e.LastHeightValidatorWasInSet <= 0 {
return errors.New("negative or zero LastHeightValidatorWasInSet")
}
return nil
}
func (e PhantomValidatorEvidence) String() string {
return fmt.Sprintf("PhantomValidatorEvidence{%X voted for %d/%X}",
e.Vote.ValidatorAddress, e.Header.Height, e.Header.Hash())
}
//-------------------------------------------
type LunaticValidatorEvidence struct {
Header *Header `json:"header"`
Vote *Vote `json:"vote"`
InvalidHeaderField string `json:"invalid_header_field"`
}
var _ Evidence = &LunaticValidatorEvidence{}
var _ Evidence = LunaticValidatorEvidence{}
func (e LunaticValidatorEvidence) Height() int64 {
return e.Header.Height
}
func (e LunaticValidatorEvidence) Time() time.Time {
return e.Header.Time
}
func (e LunaticValidatorEvidence) Address() []byte {
return e.Vote.ValidatorAddress
}
func (e LunaticValidatorEvidence) Hash() []byte {
bz := make([]byte, tmhash.Size+crypto.AddressSize)
copy(bz[:tmhash.Size-1], e.Header.Hash().Bytes())
copy(bz[tmhash.Size:], e.Vote.ValidatorAddress.Bytes())
return tmhash.Sum(bz)
}
func (e LunaticValidatorEvidence) Bytes() []byte {
return cdcEncode(e)
}
func (e LunaticValidatorEvidence) Verify(chainID string, pubKey crypto.PubKey) error {
// chainID must be the same
if chainID != e.Header.ChainID {
return fmt.Errorf("chainID do not match: %s vs %s",
chainID,
e.Header.ChainID,
)
}
if !pubKey.VerifyBytes(e.Vote.SignBytes(chainID), e.Vote.Signature) {
return errors.New("invalid signature")
}
return nil
}
func (e LunaticValidatorEvidence) Equal(ev Evidence) bool {
switch e2 := ev.(type) {
case LunaticValidatorEvidence:
return bytes.Equal(e.Header.Hash(), e2.Header.Hash()) &&
bytes.Equal(e.Vote.ValidatorAddress, e2.Vote.ValidatorAddress)
case *LunaticValidatorEvidence:
return bytes.Equal(e.Header.Hash(), e2.Header.Hash()) &&
bytes.Equal(e.Vote.ValidatorAddress, e2.Vote.ValidatorAddress)
default:
return false
}
}
func (e LunaticValidatorEvidence) ValidateBasic() error {
if e.Header == nil {
return errors.New("empty header")
}
if e.Vote == nil {
return errors.New("empty vote")
}
if err := e.Header.ValidateBasic(); err != nil {
return fmt.Errorf("invalid header: %v", err)
}
if err := e.Vote.ValidateBasic(); err != nil {
return fmt.Errorf("invalid signature: %v", err)
}
if !e.Vote.BlockID.IsComplete() {
return errors.New("expected vote for block")
}
if e.Header.Height != e.Vote.Height {
return fmt.Errorf("header and vote have different heights: %d vs %d",
e.Header.Height,
e.Vote.Height,
)
}
switch e.InvalidHeaderField {
case "ValidatorsHash", "NextValidatorsHash", "ConsensusHash", "AppHash", "LastResultsHash":
return nil
default:
return errors.New("unknown invalid header field")
}
}
func (e LunaticValidatorEvidence) String() string {
return fmt.Sprintf("LunaticValidatorEvidence{%X voted for %d/%X, which contains invalid %s}",
e.Vote.ValidatorAddress, e.Header.Height, e.Header.Hash(), e.InvalidHeaderField)
}
func (e LunaticValidatorEvidence) VerifyHeader(committedHeader *Header) error {
matchErr := func(field string) error {
return fmt.Errorf("%s matches committed hash", field)
}
switch e.InvalidHeaderField {
case ValidatorsHashField:
if bytes.Equal(committedHeader.ValidatorsHash, e.Header.ValidatorsHash) {
return matchErr(ValidatorsHashField)
}
case NextValidatorsHashField:
if bytes.Equal(committedHeader.NextValidatorsHash, e.Header.NextValidatorsHash) {
return matchErr(NextValidatorsHashField)
}
case ConsensusHashField:
if bytes.Equal(committedHeader.ConsensusHash, e.Header.ConsensusHash) {
return matchErr(ConsensusHashField)
}
case AppHashField:
if bytes.Equal(committedHeader.AppHash, e.Header.AppHash) {
return matchErr(AppHashField)
}
case LastResultsHashField:
if bytes.Equal(committedHeader.LastResultsHash, e.Header.LastResultsHash) {
return matchErr(LastResultsHashField)
}
default:
return errors.New("unknown InvalidHeaderField")
}
return nil
}
//-------------------------------------------
type PotentialAmnesiaEvidence struct {
VoteA *Vote `json:"vote_a"`
VoteB *Vote `json:"vote_b"`
}
var _ Evidence = &PotentialAmnesiaEvidence{}
var _ Evidence = PotentialAmnesiaEvidence{}
func (e PotentialAmnesiaEvidence) Height() int64 {
return e.VoteA.Height
}
func (e PotentialAmnesiaEvidence) Time() time.Time {
if e.VoteA.Timestamp.Before(e.VoteB.Timestamp) {
return e.VoteA.Timestamp
}
return e.VoteB.Timestamp
}
func (e PotentialAmnesiaEvidence) Address() []byte {
return e.VoteA.ValidatorAddress
}
func (e PotentialAmnesiaEvidence) Hash() []byte {
return tmhash.Sum(cdcEncode(e))
}
func (e PotentialAmnesiaEvidence) Bytes() []byte {
return cdcEncode(e)
}
func (e PotentialAmnesiaEvidence) Verify(chainID string, pubKey crypto.PubKey) error {
// pubkey must match address (this should already be true, sanity check)
addr := e.VoteA.ValidatorAddress
if !bytes.Equal(pubKey.Address(), addr) {
return fmt.Errorf("address (%X) doesn't match pubkey (%v - %X)",
addr, pubKey, pubKey.Address())
}
// Signatures must be valid
if !pubKey.VerifyBytes(e.VoteA.SignBytes(chainID), e.VoteA.Signature) {
return fmt.Errorf("verifying VoteA: %w", ErrVoteInvalidSignature)
}
if !pubKey.VerifyBytes(e.VoteB.SignBytes(chainID), e.VoteB.Signature) {
return fmt.Errorf("verifying VoteB: %w", ErrVoteInvalidSignature)
}
return nil
}
func (e PotentialAmnesiaEvidence) Equal(ev Evidence) bool {
switch e2 := ev.(type) {
case PotentialAmnesiaEvidence:
return bytes.Equal(e.Hash(), e2.Hash())
case *PotentialAmnesiaEvidence:
return bytes.Equal(e.Hash(), e2.Hash())
default:
return false
}
}
func (e PotentialAmnesiaEvidence) ValidateBasic() error {
if e.VoteA == nil || e.VoteB == nil {
return fmt.Errorf("one or both of the votes are empty %v, %v", e.VoteA, e.VoteB)
}
if err := e.VoteA.ValidateBasic(); err != nil {
return fmt.Errorf("invalid VoteA: %v", err)
}
if err := e.VoteB.ValidateBasic(); err != nil {
return fmt.Errorf("invalid VoteB: %v", err)
}
// Enforce Votes are lexicographically sorted on blockID
if strings.Compare(e.VoteA.BlockID.Key(), e.VoteB.BlockID.Key()) >= 0 {
return errors.New("amnesia votes in invalid order")
}
// H/S must be the same
if e.VoteA.Height != e.VoteB.Height ||
e.VoteA.Type != e.VoteB.Type {
return fmt.Errorf("h/s do not match: %d/%v vs %d/%v",
e.VoteA.Height, e.VoteA.Type, e.VoteB.Height, e.VoteB.Type)
}
// R must be different
if e.VoteA.Round == e.VoteB.Round {
return fmt.Errorf("expected votes from different rounds, got %d", e.VoteA.Round)
}
// Address must be the same
if !bytes.Equal(e.VoteA.ValidatorAddress, e.VoteB.ValidatorAddress) {
return fmt.Errorf("validator addresses do not match: %X vs %X",
e.VoteA.ValidatorAddress,
e.VoteB.ValidatorAddress,
)
}
// Index must be the same
// https://github.com/tendermint/tendermint/issues/4619
if e.VoteA.ValidatorIndex != e.VoteB.ValidatorIndex {
return fmt.Errorf(
"duplicateVoteEvidence Error: Validator indices do not match. Got %d and %d",
e.VoteA.ValidatorIndex,
e.VoteB.ValidatorIndex,
)
}
// BlockIDs must be different
if e.VoteA.BlockID.Equals(e.VoteB.BlockID) {
return fmt.Errorf(
"block IDs are the same (%v) - not a real duplicate vote",
e.VoteA.BlockID,
)
}
return nil
}
func (e PotentialAmnesiaEvidence) String() string {
return fmt.Sprintf("PotentialAmnesiaEvidence{VoteA: %v, VoteB: %v}", e.VoteA, e.VoteB)
}
// ProofOfLockChange (POLC) proves that a node followed the consensus protocol and voted for a precommit in two
// different rounds because the node received a majority of votes for a different block in the latter round. In cases of
// amnesia evidence, a suspected node will need ProofOfLockChange to prove that the node did not break protocol.
type ProofOfLockChange struct {
Votes []Vote `json:"votes"`
PubKey crypto.PubKey `json:"pubkey"`
}
// MakePOLCFromVoteSet can be used when a majority of prevotes or precommits for a block is seen
// that the node has itself not yet voted for in order to process the vote set into a proof of lock change
func MakePOLCFromVoteSet(voteSet *VoteSet, pubKey crypto.PubKey, blockID BlockID) (ProofOfLockChange, error) {
polc := makePOLCFromVoteSet(voteSet, pubKey, blockID)
return polc, polc.ValidateBasic()
}
func makePOLCFromVoteSet(voteSet *VoteSet, pubKey crypto.PubKey, blockID BlockID) ProofOfLockChange {
var votes []Vote
valSetSize := voteSet.Size()
for valIdx := 0; valIdx < valSetSize; valIdx++ {
vote := voteSet.GetByIndex(valIdx)
if vote != nil && vote.BlockID.Equals(blockID) {
votes = append(votes, *vote)
}
}
return ProofOfLockChange{
Votes: votes,
PubKey: pubKey,
}
}
func (e ProofOfLockChange) Height() int64 {
return e.Votes[0].Height
}
// returns the time of the last vote
func (e ProofOfLockChange) Time() time.Time {
latest := e.Votes[0].Timestamp
for _, vote := range e.Votes {
if vote.Timestamp.After(latest) {
latest = vote.Timestamp
}
}
return latest
}
func (e ProofOfLockChange) Round() int {
return e.Votes[0].Round
}
func (e ProofOfLockChange) Address() []byte {
return e.PubKey.Address()
}
func (e ProofOfLockChange) BlockID() BlockID {
return e.Votes[0].BlockID
}
// In order for a ProofOfLockChange to be valid, a validator must have received +2/3 majority of votes
// MajorityOfVotes checks that there were sufficient votes in order to change locks
func (e ProofOfLockChange) MajorityOfVotes(valSet *ValidatorSet) bool {
talliedVotingPower := int64(0)
votingPowerNeeded := valSet.TotalVotingPower() * 2 / 3
for _, validator := range valSet.Validators {
for _, vote := range e.Votes {
if bytes.Equal(validator.Address, vote.ValidatorAddress) {
talliedVotingPower += validator.VotingPower
if talliedVotingPower > votingPowerNeeded {
return true
}
}
}
}
return false
}
func (e ProofOfLockChange) Equal(e2 ProofOfLockChange) bool {
return bytes.Equal(e.Address(), e2.Address()) && e.Height() == e2.Height() &&
e.Round() == e2.Round()
}
func (e ProofOfLockChange) ValidateBasic() error {
if e.PubKey == nil {
return errors.New("missing public key")
}
// validate basic doesn't count the number of votes and their voting power, this is to be done by VerifyEvidence
if e.Votes == nil {
return errors.New("missing votes")
}
// height, round and vote type must be the same for all votes
height := e.Height()
round := e.Round()
if round == 0 {
return errors.New("can't have a polc for the first round")
}
voteType := e.Votes[0].Type
for idx, vote := range e.Votes {
if err := vote.ValidateBasic(); err != nil {
return fmt.Errorf("invalid vote#%d: %w", idx, err)
}
if vote.Height != height {
return fmt.Errorf("invalid height for vote#%d: %d instead of %d", idx, vote.Height, height)
}
if vote.Round != round {
return fmt.Errorf("invalid round for vote#%d: %d instead of %d", idx, vote.Round, round)
}
if vote.Type != voteType {
return fmt.Errorf("invalid vote type for vote#%d: %d instead of %d", idx, vote.Type, voteType)
}
if !vote.BlockID.Equals(e.BlockID()) {
return fmt.Errorf("vote must be for the same block id: %v instead of %v", e.BlockID(), vote.BlockID)
}
if bytes.Equal(vote.ValidatorAddress.Bytes(), e.PubKey.Address().Bytes()) {
return fmt.Errorf("vote validator address cannot be the same as the public key address: %X all votes %v",
vote.ValidatorAddress.Bytes(), e.Votes)
}
for i := idx + 1; i < len(e.Votes); i++ {
if bytes.Equal(vote.ValidatorAddress.Bytes(), e.Votes[i].ValidatorAddress.Bytes()) {
return fmt.Errorf("duplicate votes: %v", vote)
}
}
}
return nil
}
func (e ProofOfLockChange) String() string {
return fmt.Sprintf("ProofOfLockChange {Address: %X, Height: %d, Round: %d", e.Address(), e.Height(),
e.Votes[0].Round)
}
//-----------------------------------------------------------------
// UNSTABLE
type MockRandomEvidence struct {
MockEvidence
randBytes []byte
}
var _ Evidence = &MockRandomEvidence{}
// UNSTABLE
func NewMockRandomEvidence(height int64, eTime time.Time, address []byte, randBytes []byte) MockRandomEvidence {
return MockRandomEvidence{
MockEvidence{
EvidenceHeight: height,
EvidenceTime: eTime,
EvidenceAddress: address}, randBytes,
}
}
func (e MockRandomEvidence) Hash() []byte {
return []byte(fmt.Sprintf("%d-%x", e.EvidenceHeight, e.randBytes))
}
func (e MockRandomEvidence) Equal(ev Evidence) bool { return false }
// UNSTABLE
type MockEvidence struct {
EvidenceHeight int64
EvidenceTime time.Time
EvidenceAddress []byte
}
var _ Evidence = &MockEvidence{}
// UNSTABLE
func NewMockEvidence(height int64, eTime time.Time, address []byte) MockEvidence {
return MockEvidence{
EvidenceHeight: height,
EvidenceTime: eTime,
EvidenceAddress: address}
}
func (e MockEvidence) Height() int64 { return e.EvidenceHeight }
func (e MockEvidence) Time() time.Time { return e.EvidenceTime }
func (e MockEvidence) Address() []byte { return e.EvidenceAddress }
func (e MockEvidence) Hash() []byte {
return []byte(fmt.Sprintf("%d-%x-%s",
e.EvidenceHeight, e.EvidenceAddress, e.EvidenceTime))
}
func (e MockEvidence) Bytes() []byte {
return []byte(fmt.Sprintf("%d-%x-%s",
e.EvidenceHeight, e.EvidenceAddress, e.EvidenceTime))
}
func (e MockEvidence) Verify(chainID string, pubKey crypto.PubKey) error { return nil }
func (e MockEvidence) Equal(ev Evidence) bool {
return e.EvidenceHeight == ev.Height() &&
bytes.Equal(e.EvidenceAddress, ev.Address())
}
func (e MockEvidence) ValidateBasic() error { return nil }
func (e MockEvidence) String() string {
return fmt.Sprintf("Evidence: %d/%s/%s", e.EvidenceHeight, e.Time(), e.EvidenceAddress)
}
// mock polc - fails validate basic, not stable
func NewMockPOLC(height int64, time time.Time, pubKey crypto.PubKey) ProofOfLockChange {
voteVal := NewMockPV()
pKey, _ := voteVal.GetPubKey()
vote := Vote{Type: PrecommitType, Height: height, Round: 1, BlockID: BlockID{},
Timestamp: time, ValidatorAddress: pKey.Address(), ValidatorIndex: 1, Signature: []byte{}}
_ = voteVal.SignVote("mock-chain-id", &vote)
return ProofOfLockChange{
Votes: []Vote{vote},
PubKey: pubKey,
}
}