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// Copyright 2017 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
// Package keystore implements encrypted storage of secp256k1 private keys.
//
// Keys are stored as encrypted JSON files according to the Web3 Secret Storage specification.
// See https://github.com/ethereum/wiki/wiki/Web3-Secret-Storage-Definition for more information.
package keystore
import (
"crypto/ecdsa"
crand "crypto/rand"
"errors"
"fmt"
"math/big"
"os"
"path/filepath"
"reflect"
"runtime"
"sync"
"time"
"github.com/ethereum/go-ethereum/accounts"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/event"
)
var (
ErrLocked = accounts.NewAuthNeededError("password or unlock")
ErrNoMatch = errors.New("no key for given address or file")
ErrDecrypt = errors.New("could not decrypt key with given passphrase")
)
// KeyStoreType is the reflect type of a keystore backend.
var KeyStoreType = reflect.TypeOf(&KeyStore{})
// KeyStoreScheme is the protocol scheme prefixing account and wallet URLs.
const KeyStoreScheme = "keystore"
// Maximum time between wallet refreshes (if filesystem notifications don't work).
const walletRefreshCycle = 3 * time.Second
// KeyStore manages a key storage directory on disk.
type KeyStore struct {
storage keyStore // Storage backend, might be cleartext or encrypted
cache *accountCache // In-memory account cache over the filesystem storage
changes chan struct{} // Channel receiving change notifications from the cache
unlocked map[common.Address]*unlocked // Currently unlocked account (decrypted private keys)
wallets []accounts.Wallet // Wallet wrappers around the individual key files
updateFeed event.Feed // Event feed to notify wallet additions/removals
updateScope event.SubscriptionScope // Subscription scope tracking current live listeners
updating bool // Whether the event notification loop is running
mu sync.RWMutex
}
type unlocked struct {
*Key
abort chan struct{}
}
// NewKeyStore creates a keystore for the given directory.
func NewKeyStore(keydir string, scryptN, scryptP int) *KeyStore {
keydir, _ = filepath.Abs(keydir)
ks := &KeyStore{storage: &keyStorePassphrase{keydir, scryptN, scryptP, false}}
ks.init(keydir)
return ks
}
// NewPlaintextKeyStore creates a keystore for the given directory.
// Deprecated: Use NewKeyStore.
func NewPlaintextKeyStore(keydir string) *KeyStore {
keydir, _ = filepath.Abs(keydir)
ks := &KeyStore{storage: &keyStorePlain{keydir}}
ks.init(keydir)
return ks
}
func (ks *KeyStore) init(keydir string) {
// Lock the mutex since the account cache might call back with events
ks.mu.Lock()
defer ks.mu.Unlock()
// Initialize the set of unlocked keys and the account cache
ks.unlocked = make(map[common.Address]*unlocked)
ks.cache, ks.changes = newAccountCache(keydir)
// TODO: In order for this finalizer to work, there must be no references
// to ks. addressCache doesn't keep a reference but unlocked keys do,
// so the finalizer will not trigger until all timed unlocks have expired.
runtime.SetFinalizer(ks, func(m *KeyStore) {
m.cache.close()
})
// Create the initial list of wallets from the cache
accs := ks.cache.accounts()
ks.wallets = make([]accounts.Wallet, len(accs))
for i := 0; i < len(accs); i++ {
ks.wallets[i] = &keystoreWallet{account: accs[i], keystore: ks}
}
}
// Wallets implements accounts.Backend, returning all single-key wallets from the
// keystore directory.
func (ks *KeyStore) Wallets() []accounts.Wallet {
// Make sure the list of wallets is in sync with the account cache
ks.refreshWallets()
ks.mu.RLock()
defer ks.mu.RUnlock()
cpy := make([]accounts.Wallet, len(ks.wallets))
copy(cpy, ks.wallets)
return cpy
}
// refreshWallets retrieves the current account list and based on that does any
// necessary wallet refreshes.
func (ks *KeyStore) refreshWallets() {
// Retrieve the current list of accounts
ks.mu.Lock()
accs := ks.cache.accounts()
// Transform the current list of wallets into the new one
wallets := make([]accounts.Wallet, 0, len(accs))
events := []accounts.WalletEvent{}
for _, account := range accs {
// Drop wallets while they were in front of the next account
for len(ks.wallets) > 0 && ks.wallets[0].URL().Cmp(account.URL) < 0 {
events = append(events, accounts.WalletEvent{Wallet: ks.wallets[0], Kind: accounts.WalletDropped})
ks.wallets = ks.wallets[1:]
}
// If there are no more wallets or the account is before the next, wrap new wallet
if len(ks.wallets) == 0 || ks.wallets[0].URL().Cmp(account.URL) > 0 {
wallet := &keystoreWallet{account: account, keystore: ks}
events = append(events, accounts.WalletEvent{Wallet: wallet, Kind: accounts.WalletArrived})
wallets = append(wallets, wallet)
continue
}
// If the account is the same as the first wallet, keep it
if ks.wallets[0].Accounts()[0] == account {
wallets = append(wallets, ks.wallets[0])
ks.wallets = ks.wallets[1:]
continue
}
}
// Drop any leftover wallets and set the new batch
for _, wallet := range ks.wallets {
events = append(events, accounts.WalletEvent{Wallet: wallet, Kind: accounts.WalletDropped})
}
ks.wallets = wallets
ks.mu.Unlock()
// Fire all wallet events and return
for _, event := range events {
ks.updateFeed.Send(event)
}
}
// Subscribe implements accounts.Backend, creating an async subscription to
// receive notifications on the addition or removal of keystore wallets.
func (ks *KeyStore) Subscribe(sink chan<- accounts.WalletEvent) event.Subscription {
// We need the mutex to reliably start/stop the update loop
ks.mu.Lock()
defer ks.mu.Unlock()
// Subscribe the caller and track the subscriber count
sub := ks.updateScope.Track(ks.updateFeed.Subscribe(sink))
// Subscribers require an active notification loop, start it
if !ks.updating {
ks.updating = true
go ks.updater()
}
return sub
}
// updater is responsible for maintaining an up-to-date list of wallets stored in
// the keystore, and for firing wallet addition/removal events. It listens for
// account change events from the underlying account cache, and also periodically
// forces a manual refresh (only triggers for systems where the filesystem notifier
// is not running).
func (ks *KeyStore) updater() {
for {
// Wait for an account update or a refresh timeout
select {
case <-ks.changes:
case <-time.After(walletRefreshCycle):
}
// Run the wallet refresher
ks.refreshWallets()
// If all our subscribers left, stop the updater
ks.mu.Lock()
if ks.updateScope.Count() == 0 {
ks.updating = false
ks.mu.Unlock()
return
}
ks.mu.Unlock()
}
}
// HasAddress reports whether a key with the given address is present.
func (ks *KeyStore) HasAddress(addr common.Address) bool {
return ks.cache.hasAddress(addr)
}
// Accounts returns all key files present in the directory.
func (ks *KeyStore) Accounts() []accounts.Account {
return ks.cache.accounts()
}
// Delete deletes the key matched by account if the passphrase is correct.
// If the account contains no filename, the address must match a unique key.
func (ks *KeyStore) Delete(a accounts.Account, passphrase string) error {
// Decrypting the key isn't really necessary, but we do
// it anyway to check the password and zero out the key
// immediately afterwards.
a, key, err := ks.getDecryptedKey(a, passphrase)
if key != nil {
zeroKey(key.PrivateKey)
}
if err != nil {
return err
}
// The order is crucial here. The key is dropped from the
// cache after the file is gone so that a reload happening in
// between won't insert it into the cache again.
err = os.Remove(a.URL.Path)
if err == nil {
ks.cache.delete(a)
ks.refreshWallets()
}
return err
}
// SignHash calculates a ECDSA signature for the given hash. The produced
// signature is in the [R || S || V] format where V is 0 or 1.
func (ks *KeyStore) SignHash(a accounts.Account, hash []byte) ([]byte, error) {
// Look up the key to sign with and abort if it cannot be found
ks.mu.RLock()
defer ks.mu.RUnlock()
unlockedKey, found := ks.unlocked[a.Address]
if !found {
return nil, ErrLocked
}
// Sign the hash using plain ECDSA operations
return crypto.Sign(hash, unlockedKey.PrivateKey)
}
// SignTx signs the given transaction with the requested account.
func (ks *KeyStore) SignTx(a accounts.Account, tx *types.Transaction, chainID *big.Int) (*types.Transaction, error) {
// Look up the key to sign with and abort if it cannot be found
ks.mu.RLock()
defer ks.mu.RUnlock()
unlockedKey, found := ks.unlocked[a.Address]
if !found {
return nil, ErrLocked
}
// Depending on the presence of the chain ID, sign with EIP155 or homestead
if chainID != nil {
return types.SignTx(tx, types.NewEIP155Signer(chainID), unlockedKey.PrivateKey)
}
return types.SignTx(tx, types.HomesteadSigner{}, unlockedKey.PrivateKey)
}
// SignHashWithPassphrase signs hash if the private key matching the given address
// can be decrypted with the given passphrase. The produced signature is in the
// [R || S || V] format where V is 0 or 1.
func (ks *KeyStore) SignHashWithPassphrase(a accounts.Account, passphrase string, hash []byte) (signature []byte, err error) {
_, key, err := ks.getDecryptedKey(a, passphrase)
if err != nil {
return nil, err
}
defer zeroKey(key.PrivateKey)
return crypto.Sign(hash, key.PrivateKey)
}
// SignTxWithPassphrase signs the transaction if the private key matching the
// given address can be decrypted with the given passphrase.
func (ks *KeyStore) SignTxWithPassphrase(a accounts.Account, passphrase string, tx *types.Transaction, chainID *big.Int) (*types.Transaction, error) {
_, key, err := ks.getDecryptedKey(a, passphrase)
if err != nil {
return nil, err
}
defer zeroKey(key.PrivateKey)
// Depending on the presence of the chain ID, sign with EIP155 or homestead
if chainID != nil {
return types.SignTx(tx, types.NewEIP155Signer(chainID), key.PrivateKey)
}
return types.SignTx(tx, types.HomesteadSigner{}, key.PrivateKey)
}
// Unlock unlocks the given account indefinitely.
func (ks *KeyStore) Unlock(a accounts.Account, passphrase string) error {
return ks.TimedUnlock(a, passphrase, 0)
}
// Lock removes the private key with the given address from memory.
func (ks *KeyStore) Lock(addr common.Address) error {
ks.mu.Lock()
if unl, found := ks.unlocked[addr]; found {
ks.mu.Unlock()
ks.expire(addr, unl, time.Duration(0)*time.Nanosecond)
} else {
ks.mu.Unlock()
}
return nil
}
// TimedUnlock unlocks the given account with the passphrase. The account
// stays unlocked for the duration of timeout. A timeout of 0 unlocks the account
// until the program exits. The account must match a unique key file.
//
// If the account address is already unlocked for a duration, TimedUnlock extends or
// shortens the active unlock timeout. If the address was previously unlocked
// indefinitely the timeout is not altered.
func (ks *KeyStore) TimedUnlock(a accounts.Account, passphrase string, timeout time.Duration) error {
a, key, err := ks.getDecryptedKey(a, passphrase)
if err != nil {
return err
}
ks.mu.Lock()
defer ks.mu.Unlock()
u, found := ks.unlocked[a.Address]
if found {
if u.abort == nil {
// The address was unlocked indefinitely, so unlocking
// it with a timeout would be confusing.
zeroKey(key.PrivateKey)
return nil
}
// Terminate the expire goroutine and replace it below.
close(u.abort)
}
if timeout > 0 {
u = &unlocked{Key: key, abort: make(chan struct{})}
go ks.expire(a.Address, u, timeout)
} else {
u = &unlocked{Key: key}
}
ks.unlocked[a.Address] = u
return nil
}
// Find resolves the given account into a unique entry in the keystore.
func (ks *KeyStore) Find(a accounts.Account) (accounts.Account, error) {
ks.cache.maybeReload()
ks.cache.mu.Lock()
a, err := ks.cache.find(a)
ks.cache.mu.Unlock()
return a, err
}
func (ks *KeyStore) getDecryptedKey(a accounts.Account, auth string) (accounts.Account, *Key, error) {
a, err := ks.Find(a)
if err != nil {
return a, nil, err
}
key, err := ks.storage.GetKey(a.Address, a.URL.Path, auth)
return a, key, err
}
func (ks *KeyStore) expire(addr common.Address, u *unlocked, timeout time.Duration) {
t := time.NewTimer(timeout)
defer t.Stop()
select {
case <-u.abort:
// just quit
case <-t.C:
ks.mu.Lock()
// only drop if it's still the same key instance that dropLater
// was launched with. we can check that using pointer equality
// because the map stores a new pointer every time the key is
// unlocked.
if ks.unlocked[addr] == u {
zeroKey(u.PrivateKey)
delete(ks.unlocked, addr)
}
ks.mu.Unlock()
}
}
// NewAccount generates a new key and stores it into the key directory,
// encrypting it with the passphrase.
func (ks *KeyStore) NewAccount(passphrase string) (accounts.Account, error) {
_, account, err := storeNewKey(ks.storage, crand.Reader, passphrase)
if err != nil {
return accounts.Account{}, err
}
// Add the account to the cache immediately rather
// than waiting for file system notifications to pick it up.
ks.cache.add(account)
ks.refreshWallets()
return account, nil
}
// Export exports as a JSON key, encrypted with newPassphrase.
func (ks *KeyStore) Export(a accounts.Account, passphrase, newPassphrase string) (keyJSON []byte, err error) {
_, key, err := ks.getDecryptedKey(a, passphrase)
if err != nil {
return nil, err
}
var N, P int
if store, ok := ks.storage.(*keyStorePassphrase); ok {
N, P = store.scryptN, store.scryptP
} else {
N, P = StandardScryptN, StandardScryptP
}
return EncryptKey(key, newPassphrase, N, P)
}
// Import stores the given encrypted JSON key into the key directory.
func (ks *KeyStore) Import(keyJSON []byte, passphrase, newPassphrase string) (accounts.Account, error) {
key, err := DecryptKey(keyJSON, passphrase)
if key != nil && key.PrivateKey != nil {
defer zeroKey(key.PrivateKey)
}
if err != nil {
return accounts.Account{}, err
}
return ks.importKey(key, newPassphrase)
}
// ImportECDSA stores the given key into the key directory, encrypting it with the passphrase.
func (ks *KeyStore) ImportECDSA(priv *ecdsa.PrivateKey, passphrase string) (accounts.Account, error) {
key := newKeyFromECDSA(priv)
if ks.cache.hasAddress(key.Address) {
return accounts.Account{}, fmt.Errorf("account already exists")
}
return ks.importKey(key, passphrase)
}
func (ks *KeyStore) importKey(key *Key, passphrase string) (accounts.Account, error) {
a := accounts.Account{Address: key.Address, URL: accounts.URL{Scheme: KeyStoreScheme, Path: ks.storage.JoinPath(keyFileName(key.Address))}}
if err := ks.storage.StoreKey(a.URL.Path, key, passphrase); err != nil {
return accounts.Account{}, err
}
ks.cache.add(a)
ks.refreshWallets()
return a, nil
}
// Update changes the passphrase of an existing account.
func (ks *KeyStore) Update(a accounts.Account, passphrase, newPassphrase string) error {
a, key, err := ks.getDecryptedKey(a, passphrase)
if err != nil {
return err
}
return ks.storage.StoreKey(a.URL.Path, key, newPassphrase)
}
// ImportPreSaleKey decrypts the given Ethereum presale wallet and stores
// a key file in the key directory. The key file is encrypted with the same passphrase.
func (ks *KeyStore) ImportPreSaleKey(keyJSON []byte, passphrase string) (accounts.Account, error) {
a, _, err := importPreSaleKey(ks.storage, keyJSON, passphrase)
if err != nil {
return a, err
}
ks.cache.add(a)
ks.refreshWallets()
return a, nil
}
// zeroKey zeroes a private key in memory.
func zeroKey(k *ecdsa.PrivateKey) {
b := k.D.Bits()
for i := range b {
b[i] = 0
}
}