path: root/accounts/account_manager.go

// Copyright 2015 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 implements a private key management facility.
//
// This abstracts part of a user's interaction with an account she controls.
package accounts

// Currently this is pretty much a passthrough to the KeyStore interface,
// and accounts persistence is derived from stored keys' addresses

import (
    "crypto/ecdsa"
    crand "crypto/rand"
    "errors"
    "fmt"
    "os"
    "sync"
    "time"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/crypto"
)

var (
    ErrLocked = errors.New("account is locked")
    ErrNoKeys = errors.New("no keys in store")
)

type Account struct {
    Address common.Address
}

type Manager struct {
    keyStore crypto.KeyStore
    unlocked map[common.Address]*unlocked
    mutex    sync.RWMutex
}

type unlocked struct {
    *crypto.Key
    abort chan struct{}
}

func NewManager(keyStore crypto.KeyStore) *Manager {
    return &Manager{
        keyStore: keyStore,
        unlocked: make(map[common.Address]*unlocked),
    }
}

func (am *Manager) HasAccount(addr common.Address) bool {
    accounts, _ := am.Accounts()
    for _, acct := range accounts {
        if acct.Address == addr {
            return true
        }
    }
    return false
}

func (am *Manager) DeleteAccount(address common.Address, auth string) error {
    return am.keyStore.DeleteKey(address, auth)
}

func (am *Manager) Sign(a Account, toSign []byte) (signature []byte, err error) {
    am.mutex.RLock()
    defer am.mutex.RUnlock()
    unlockedKey, found := am.unlocked[a.Address]
    if !found {
        return nil, ErrLocked
    }
    signature, err = crypto.Sign(toSign, unlockedKey.PrivateKey)
    return signature, err
}

// Unlock unlocks the given account indefinitely.
func (am *Manager) Unlock(addr common.Address, keyAuth string) error {
    return am.TimedUnlock(addr, keyAuth, 0)
}

// TimedUnlock unlocks the account with the given address. The account
// stays unlocked for the duration of timeout. A timeout of 0 unlocks the account
// until the program exits.
//
// If the accout is already unlocked, TimedUnlock extends or shortens
// the active unlock timeout.
func (am *Manager) TimedUnlock(addr common.Address, keyAuth string, timeout time.Duration) error {
    key, err := am.keyStore.GetKey(addr, keyAuth)
    if err != nil {
        return err
    }
    var u *unlocked
    am.mutex.Lock()
    defer am.mutex.Unlock()
    var found bool
    u, found = am.unlocked[addr]
    if found {
        // terminate dropLater for this key to avoid unexpected drops.
        if u.abort != nil {
            close(u.abort)
        }
    }
    if timeout > 0 {
        u = &unlocked{Key: key, abort: make(chan struct{})}
        go am.expire(addr, u, timeout)
    } else {
        u = &unlocked{Key: key}
    }
    am.unlocked[addr] = u
    return nil
}

func (am *Manager) 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:
        am.mutex.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 am.unlocked[addr] == u {
            zeroKey(u.PrivateKey)
            delete(am.unlocked, addr)
        }
        am.mutex.Unlock()
    }
}

func (am *Manager) NewAccount(auth string) (Account, error) {
    key, err := am.keyStore.GenerateNewKey(crand.Reader, auth)
    if err != nil {
        return Account{}, err
    }
    return Account{Address: key.Address}, nil
}

func (am *Manager) AddressByIndex(index int) (addr string, err error) {
    var addrs []common.Address
    addrs, err = am.keyStore.GetKeyAddresses()
    if err != nil {
        return
    }
    if index < 0 || index >= len(addrs) {
        err = fmt.Errorf("index out of range: %d (should be 0-%d)", index, len(addrs)-1)
    } else {
        addr = addrs[index].Hex()
    }
    return
}

func (am *Manager) Accounts() ([]Account, error) {
    addresses, err := am.keyStore.GetKeyAddresses()
    if os.IsNotExist(err) {
        return nil, ErrNoKeys
    } else if err != nil {
        return nil, err
    }
    accounts := make([]Account, len(addresses))
    for i, addr := range addresses {
        accounts[i] = Account{
            Address: addr,
        }
    }
    return accounts, err
}

// zeroKey zeroes a private key in memory.
func zeroKey(k *ecdsa.PrivateKey) {
    b := k.D.Bits()
    for i := range b {
        b[i] = 0
    }
}

// USE WITH CAUTION = this will save an unencrypted private key on disk
// no cli or js interface
func (am *Manager) Export(path string, addr common.Address, keyAuth string) error {
    key, err := am.keyStore.GetKey(addr, keyAuth)
    if err != nil {
        return err
    }
    return crypto.SaveECDSA(path, key.PrivateKey)
}

func (am *Manager) Import(path string, keyAuth string) (Account, error) {
    privateKeyECDSA, err := crypto.LoadECDSA(path)
    if err != nil {
        return Account{}, err
    }
    key := crypto.NewKeyFromECDSA(privateKeyECDSA)
    if err = am.keyStore.StoreKey(key, keyAuth); err != nil {
        return Account{}, err
    }
    return Account{Address: key.Address}, nil
}

func (am *Manager) Update(addr common.Address, authFrom, authTo string) (err error) {
    var key *crypto.Key
    key, err = am.keyStore.GetKey(addr, authFrom)

    if err == nil {
        err = am.keyStore.StoreKey(key, authTo)
        if err == nil {
            am.keyStore.Cleanup(addr)
        }
    }
    return
}

func (am *Manager) ImportPreSaleKey(keyJSON []byte, password string) (acc Account, err error) {
    var key *crypto.Key
    key, err = crypto.ImportPreSaleKey(am.keyStore, keyJSON, password)
    if err != nil {
        return
    }
    return Account{Address: key.Address}, nil
}