file.go
package privval
import (
"bytes"
"errors"
"fmt"
"io/ioutil"
"time"
"github.com/tendermint/tendermint/crypto"
"github.com/tendermint/tendermint/crypto/ed25519"
cmn "github.com/tendermint/tendermint/libs/common"
"github.com/tendermint/tendermint/types"
tmtime "github.com/tendermint/tendermint/types/time"
)
// TODO: type ?
const (
stepNone int8 = 0 // Used to distinguish the initial state
stepPropose int8 = 1
stepPrevote int8 = 2
stepPrecommit int8 = 3
)
// A vote is either stepPrevote or stepPrecommit.
func voteToStep(vote *types.Vote) int8 {
switch vote.Type {
case types.PrevoteType:
return stepPrevote
case types.PrecommitType:
return stepPrecommit
default:
panic("Unknown vote type")
}
}
//-------------------------------------------------------------------------------
// FilePVKey stores the immutable part of PrivValidator.
type FilePVKey struct {
Address types.Address `json:"address"`
PubKey crypto.PubKey `json:"pub_key"`
PrivKey crypto.PrivKey `json:"priv_key"`
filePath string
}
// Save persists the FilePVKey to its filePath.
func (pvKey FilePVKey) Save() {
outFile := pvKey.filePath
if outFile == "" {
panic("cannot save PrivValidator key: filePath not set")
}
jsonBytes, err := cdc.MarshalJSONIndent(pvKey, "", " ")
if err != nil {
panic(err)
}
err = cmn.WriteFileAtomic(outFile, jsonBytes, 0600)
if err != nil {
panic(err)
}
}
//-------------------------------------------------------------------------------
// FilePVLastSignState stores the mutable part of PrivValidator.
type FilePVLastSignState struct {
Height int64 `json:"height"`
Round int `json:"round"`
Step int8 `json:"step"`
Signature []byte `json:"signature,omitempty"`
SignBytes cmn.HexBytes `json:"signbytes,omitempty"`
filePath string
}
// CheckHRS checks the given height, round, step (HRS) against that of the
// FilePVLastSignState. It returns an error if the arguments constitute a regression,
// or if they match but the SignBytes are empty.
// The returned boolean indicates whether the last Signature should be reused -
// it returns true if the HRS matches the arguments and the SignBytes are not empty (indicating
// we have already signed for this HRS, and can reuse the existing signature).
// It panics if the HRS matches the arguments, there's a SignBytes, but no Signature.
func (lss *FilePVLastSignState) CheckHRS(height int64, round int, step int8) (bool, error) {
if lss.Height > height {
return false, fmt.Errorf("height regression. Got %v, last height %v", height, lss.Height)
}
if lss.Height == height {
if lss.Round > round {
return false, fmt.Errorf("round regression at height %v. Got %v, last round %v", height, round, lss.Round)
}
if lss.Round == round {
if lss.Step > step {
return false, fmt.Errorf("step regression at height %v round %v. Got %v, last step %v", height, round, step, lss.Step)
} else if lss.Step == step {
if lss.SignBytes != nil {
if lss.Signature == nil {
panic("pv: Signature is nil but SignBytes is not!")
}
return true, nil
}
return false, errors.New("no SignBytes found")
}
}
}
return false, nil
}
// Save persists the FilePvLastSignState to its filePath.
func (lss *FilePVLastSignState) Save() {
outFile := lss.filePath
if outFile == "" {
panic("cannot save FilePVLastSignState: filePath not set")
}
jsonBytes, err := cdc.MarshalJSONIndent(lss, "", " ")
if err != nil {
panic(err)
}
err = cmn.WriteFileAtomic(outFile, jsonBytes, 0600)
if err != nil {
panic(err)
}
}
//-------------------------------------------------------------------------------
// FilePV implements PrivValidator using data persisted to disk
// to prevent double signing.
// NOTE: the directories containing pv.Key.filePath and pv.LastSignState.filePath must already exist.
// It includes the LastSignature and LastSignBytes so we don't lose the signature
// if the process crashes after signing but before the resulting consensus message is processed.
type FilePV struct {
Key FilePVKey
LastSignState FilePVLastSignState
}
// GenFilePV generates a new validator with randomly generated private key
// and sets the filePaths, but does not call Save().
func GenFilePV(keyFilePath, stateFilePath string) *FilePV {
privKey := ed25519.GenPrivKey()
return &FilePV{
Key: FilePVKey{
Address: privKey.PubKey().Address(),
PubKey: privKey.PubKey(),
PrivKey: privKey,
filePath: keyFilePath,
},
LastSignState: FilePVLastSignState{
Step: stepNone,
filePath: stateFilePath,
},
}
}
// LoadFilePV loads a FilePV from the filePaths. The FilePV handles double
// signing prevention by persisting data to the stateFilePath. If either file path
// does not exist, the program will exit.
func LoadFilePV(keyFilePath, stateFilePath string) *FilePV {
return loadFilePV(keyFilePath, stateFilePath, true)
}
// LoadFilePVEmptyState loads a FilePV from the given keyFilePath, with an empty LastSignState.
// If the keyFilePath does not exist, the program will exit.
func LoadFilePVEmptyState(keyFilePath, stateFilePath string) *FilePV {
return loadFilePV(keyFilePath, stateFilePath, false)
}
// If loadState is true, we load from the stateFilePath. Otherwise, we use an empty LastSignState.
func loadFilePV(keyFilePath, stateFilePath string, loadState bool) *FilePV {
keyJSONBytes, err := ioutil.ReadFile(keyFilePath)
if err != nil {
cmn.Exit(err.Error())
}
pvKey := FilePVKey{}
err = cdc.UnmarshalJSON(keyJSONBytes, &pvKey)
if err != nil {
cmn.Exit(fmt.Sprintf("Error reading PrivValidator key from %v: %v\n", keyFilePath, err))
}
// overwrite pubkey and address for convenience
pvKey.PubKey = pvKey.PrivKey.PubKey()
pvKey.Address = pvKey.PubKey.Address()
pvKey.filePath = keyFilePath
pvState := FilePVLastSignState{}
if loadState {
stateJSONBytes, err := ioutil.ReadFile(stateFilePath)
if err != nil {
cmn.Exit(err.Error())
}
err = cdc.UnmarshalJSON(stateJSONBytes, &pvState)
if err != nil {
cmn.Exit(fmt.Sprintf("Error reading PrivValidator state from %v: %v\n", stateFilePath, err))
}
}
pvState.filePath = stateFilePath
return &FilePV{
Key: pvKey,
LastSignState: pvState,
}
}
// LoadOrGenFilePV loads a FilePV from the given filePaths
// or else generates a new one and saves it to the filePaths.
func LoadOrGenFilePV(keyFilePath, stateFilePath string) *FilePV {
var pv *FilePV
if cmn.FileExists(keyFilePath) {
pv = LoadFilePV(keyFilePath, stateFilePath)
} else {
pv = GenFilePV(keyFilePath, stateFilePath)
pv.Save()
}
return pv
}
// GetAddress returns the address of the validator.
// Implements PrivValidator.
func (pv *FilePV) GetAddress() types.Address {
return pv.Key.Address
}
// GetPubKey returns the public key of the validator.
// Implements PrivValidator.
func (pv *FilePV) GetPubKey() crypto.PubKey {
return pv.Key.PubKey
}
// SignVote signs a canonical representation of the vote, along with the
// chainID. Implements PrivValidator.
func (pv *FilePV) SignVote(chainID string, vote *types.Vote) error {
if err := pv.signVote(chainID, vote); err != nil {
return fmt.Errorf("error signing vote: %v", err)
}
return nil
}
// SignProposal signs a canonical representation of the proposal, along with
// the chainID. Implements PrivValidator.
func (pv *FilePV) SignProposal(chainID string, proposal *types.Proposal) error {
if err := pv.signProposal(chainID, proposal); err != nil {
return fmt.Errorf("error signing proposal: %v", err)
}
return nil
}
// Save persists the FilePV to disk.
func (pv *FilePV) Save() {
pv.Key.Save()
pv.LastSignState.Save()
}
// Reset resets all fields in the FilePV.
// NOTE: Unsafe!
func (pv *FilePV) Reset() {
var sig []byte
pv.LastSignState.Height = 0
pv.LastSignState.Round = 0
pv.LastSignState.Step = 0
pv.LastSignState.Signature = sig
pv.LastSignState.SignBytes = nil
pv.Save()
}
// String returns a string representation of the FilePV.
func (pv *FilePV) String() string {
return fmt.Sprintf("PrivValidator{%v LH:%v, LR:%v, LS:%v}", pv.GetAddress(), pv.LastSignState.Height, pv.LastSignState.Round, pv.LastSignState.Step)
}
//------------------------------------------------------------------------------------
// signVote checks if the vote is good to sign and sets the vote signature.
// It may need to set the timestamp as well if the vote is otherwise the same as
// a previously signed vote (ie. we crashed after signing but before the vote hit the WAL).
func (pv *FilePV) signVote(chainID string, vote *types.Vote) error {
height, round, step := vote.Height, vote.Round, voteToStep(vote)
lss := pv.LastSignState
sameHRS, err := lss.CheckHRS(height, round, step)
if err != nil {
return err
}
signBytes := vote.SignBytes(chainID)
// We might crash before writing to the wal,
// causing us to try to re-sign for the same HRS.
// If signbytes are the same, use the last signature.
// If they only differ by timestamp, use last timestamp and signature
// Otherwise, return error
if sameHRS {
if bytes.Equal(signBytes, lss.SignBytes) {
vote.Signature = lss.Signature
} else if timestamp, ok := checkVotesOnlyDifferByTimestamp(lss.SignBytes, signBytes); ok {
vote.Timestamp = timestamp
vote.Signature = lss.Signature
} else {
err = fmt.Errorf("conflicting data")
}
return err
}
// It passed the checks. Sign the vote
sig, err := pv.Key.PrivKey.Sign(signBytes)
if err != nil {
return err
}
pv.saveSigned(height, round, step, signBytes, sig)
vote.Signature = sig
return nil
}
// signProposal checks if the proposal is good to sign and sets the proposal signature.
// It may need to set the timestamp as well if the proposal is otherwise the same as
// a previously signed proposal ie. we crashed after signing but before the proposal hit the WAL).
func (pv *FilePV) signProposal(chainID string, proposal *types.Proposal) error {
height, round, step := proposal.Height, proposal.Round, stepPropose
lss := pv.LastSignState
sameHRS, err := lss.CheckHRS(height, round, step)
if err != nil {
return err
}
signBytes := proposal.SignBytes(chainID)
// We might crash before writing to the wal,
// causing us to try to re-sign for the same HRS.
// If signbytes are the same, use the last signature.
// If they only differ by timestamp, use last timestamp and signature
// Otherwise, return error
if sameHRS {
if bytes.Equal(signBytes, lss.SignBytes) {
proposal.Signature = lss.Signature
} else if timestamp, ok := checkProposalsOnlyDifferByTimestamp(lss.SignBytes, signBytes); ok {
proposal.Timestamp = timestamp
proposal.Signature = lss.Signature
} else {
err = fmt.Errorf("conflicting data")
}
return err
}
// It passed the checks. Sign the proposal
sig, err := pv.Key.PrivKey.Sign(signBytes)
if err != nil {
return err
}
pv.saveSigned(height, round, step, signBytes, sig)
proposal.Signature = sig
return nil
}
// Persist height/round/step and signature
func (pv *FilePV) saveSigned(height int64, round int, step int8,
signBytes []byte, sig []byte) {
pv.LastSignState.Height = height
pv.LastSignState.Round = round
pv.LastSignState.Step = step
pv.LastSignState.Signature = sig
pv.LastSignState.SignBytes = signBytes
pv.LastSignState.Save()
}
//-----------------------------------------------------------------------------------------
// returns the timestamp from the lastSignBytes.
// returns true if the only difference in the votes is their timestamp.
func checkVotesOnlyDifferByTimestamp(lastSignBytes, newSignBytes []byte) (time.Time, bool) {
var lastVote, newVote types.CanonicalVote
if err := cdc.UnmarshalBinaryLengthPrefixed(lastSignBytes, &lastVote); err != nil {
panic(fmt.Sprintf("LastSignBytes cannot be unmarshalled into vote: %v", err))
}
if err := cdc.UnmarshalBinaryLengthPrefixed(newSignBytes, &newVote); err != nil {
panic(fmt.Sprintf("signBytes cannot be unmarshalled into vote: %v", err))
}
lastTime := lastVote.Timestamp
// set the times to the same value and check equality
now := tmtime.Now()
lastVote.Timestamp = now
newVote.Timestamp = now
lastVoteBytes, _ := cdc.MarshalJSON(lastVote)
newVoteBytes, _ := cdc.MarshalJSON(newVote)
return lastTime, bytes.Equal(newVoteBytes, lastVoteBytes)
}
// returns the timestamp from the lastSignBytes.
// returns true if the only difference in the proposals is their timestamp
func checkProposalsOnlyDifferByTimestamp(lastSignBytes, newSignBytes []byte) (time.Time, bool) {
var lastProposal, newProposal types.CanonicalProposal
if err := cdc.UnmarshalBinaryLengthPrefixed(lastSignBytes, &lastProposal); err != nil {
panic(fmt.Sprintf("LastSignBytes cannot be unmarshalled into proposal: %v", err))
}
if err := cdc.UnmarshalBinaryLengthPrefixed(newSignBytes, &newProposal); err != nil {
panic(fmt.Sprintf("signBytes cannot be unmarshalled into proposal: %v", err))
}
lastTime := lastProposal.Timestamp
// set the times to the same value and check equality
now := tmtime.Now()
lastProposal.Timestamp = now
newProposal.Timestamp = now
lastProposalBytes, _ := cdc.MarshalBinaryLengthPrefixed(lastProposal)
newProposalBytes, _ := cdc.MarshalBinaryLengthPrefixed(newProposal)
return lastTime, bytes.Equal(newProposalBytes, lastProposalBytes)
}
