// 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/ava-labs/coreth/accounts" "github.com/ava-labs/coreth/core/types" "github.com/ava-labs/go-ethereum/common" "github.com/ava-labs/go-ethereum/crypto" "github.com/ava-labs/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 password") ) // 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 var ( 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 } }