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accounts, cmd, internal, node: implement HD wallet self-derivation

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This commit is contained in:
Péter Szilágyi
2017-02-08 20:25:52 +02:00
parent c5215fdd48
commit 205ea95802
9 changed files with 383 additions and 136 deletions
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154
accounts/usbwallet/ledger_wallet.go
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@ -29,11 +29,10 @@ import (
"fmt"
"io"
"math/big"
"strconv"
"strings"
"sync"
"time"
ethereum "github.com/ethereum/go-ethereum"
"github.com/ethereum/go-ethereum/accounts"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
@ -41,10 +40,15 @@ import (
"github.com/ethereum/go-ethereum/logger/glog"
"github.com/ethereum/go-ethereum/rlp"
"github.com/karalabe/gousb/usb"
"golang.org/x/net/context"
)
// ledgerDerivationPath is the base derivation parameters used by the wallet.
var ledgerDerivationPath = []uint32{0x80000000 + 44, 0x80000000 + 60, 0x80000000 + 0, 0}
// Maximum time between wallet health checks to detect USB unplugs.
const ledgerHeartbeatCycle = time.Second
// Minimum time to wait between self derivation attempts, even it the user is
// requesting accounts like crazy.
const ledgerSelfDeriveThrottling = time.Second
// ledgerOpcode is an enumeration encoding the supported Ledger opcodes.
type ledgerOpcode byte
@ -82,9 +86,15 @@ type ledgerWallet struct {
output usb.Endpoint // Output endpoint to receive data from this device
failure error // Any failure that would make the device unusable
version [3]byte // Current version of the Ledger Ethereum app (zero if app is offline)
accounts []accounts.Account // List of derive accounts pinned on the Ledger
paths map[common.Address][]uint32 // Known derivation paths for signing operations
version [3]byte // Current version of the Ledger Ethereum app (zero if app is offline)
accounts []accounts.Account // List of derive accounts pinned on the Ledger
paths map[common.Address]accounts.DerivationPath // Known derivation paths for signing operations
selfDeriveNextPath accounts.DerivationPath // Next derivation path for account auto-discovery
selfDeriveNextAddr common.Address // Next derived account address for auto-discovery
selfDerivePrevZero common.Address // Last zero-address where auto-discovery stopped
selfDeriveChain ethereum.ChainStateReader // Blockchain state reader to discover used account with
selfDeriveTime time.Time // Timestamp of the last self-derivation to avoid thrashing
quit chan chan error
lock sync.RWMutex
@ -107,12 +117,17 @@ func (w *ledgerWallet) Status() string {
if w.device == nil {
return "Closed"
}
if w.version == [3]byte{0, 0, 0} {
if w.offline() {
return "Ethereum app offline"
}
return fmt.Sprintf("Ethereum app v%d.%d.%d online", w.version[0], w.version[1], w.version[2])
}
// offline returns whether the wallet and the Ethereum app is offline or not.
func (w *ledgerWallet) offline() bool {
return w.version == [3]byte{0, 0, 0}
}
// Open implements accounts.Wallet, attempting to open a USB connection to the
// Ledger hardware wallet. The Ledger does not require a user passphrase so that
// is silently discarded.
@ -176,13 +191,13 @@ func (w *ledgerWallet) Open(passphrase string) error {
// Wallet seems to be successfully opened, guess if the Ethereum app is running
w.device, w.input, w.output = device, input, output
w.paths = make(map[common.Address][]uint32)
w.paths = make(map[common.Address]accounts.DerivationPath)
w.quit = make(chan chan error)
defer func() {
go w.heartbeat()
}()
if _, err := w.deriveAddress(ledgerDerivationPath); err != nil {
if _, err := w.deriveAddress(accounts.DefaultBaseDerivationPath); err != nil {
// Ethereum app is not running, nothing more to do, return
return nil
}
@ -209,7 +224,7 @@ func (w *ledgerWallet) heartbeat() {
case errc = <-w.quit:
// Termination requested
continue
case <-time.After(time.Second):
case <-time.After(ledgerHeartbeatCycle):
// Heartbeat time
}
// Execute a tiny data exchange to see responsiveness
@ -242,16 +257,86 @@ func (w *ledgerWallet) Close() error {
return err
}
w.device, w.input, w.output, w.paths, w.quit = nil, nil, nil, nil, nil
w.version = [3]byte{}
return herr // If all went well, return any health-check errors
}
// Accounts implements accounts.Wallet, returning the list of accounts pinned to
// the Ledger hardware wallet.
// the Ledger hardware wallet. If self derivation was enabled, the account list
// is periodically expanded based on current chain state.
func (w *ledgerWallet) Accounts() []accounts.Account {
w.lock.RLock()
defer w.lock.RUnlock()
w.lock.Lock()
defer w.lock.Unlock()
// If the wallet is offline, there are no accounts to return
if w.offline() {
return nil
}
// If no self derivation is done (or throttled), return the current accounts
if w.selfDeriveChain == nil || time.Since(w.selfDeriveTime) < ledgerSelfDeriveThrottling {
cpy := make([]accounts.Account, len(w.accounts))
copy(cpy, w.accounts)
return cpy
}
// Self derivation requested, try to expand our account list
ctx := context.Background()
for empty := false; !empty; {
// Retrieve the next derived Ethereum account
var err error
if w.selfDeriveNextAddr == (common.Address{}) {
w.selfDeriveNextAddr, err = w.deriveAddress(w.selfDeriveNextPath)
if err != nil {
// Derivation failed, disable auto discovery
glog.V(logger.Warn).Infof("self-derivation failed: %v", err)
w.selfDeriveChain = nil
break
}
}
// Check the account's status against the current chain state
balance, err := w.selfDeriveChain.BalanceAt(ctx, w.selfDeriveNextAddr, nil)
if err != nil {
glog.V(logger.Warn).Infof("self-derivation balance retrieval failed: %v", err)
w.selfDeriveChain = nil
break
}
nonce, err := w.selfDeriveChain.NonceAt(ctx, w.selfDeriveNextAddr, nil)
if err != nil {
glog.V(logger.Warn).Infof("self-derivation nonce retrieval failed: %v", err)
w.selfDeriveChain = nil
break
}
// If the next account is empty, stop self-derivation, but add it nonetheless
if balance.BitLen() == 0 && nonce == 0 {
w.selfDerivePrevZero = w.selfDeriveNextAddr
empty = true
}
// We've just self-derived a new non-zero account, start tracking it
path := make(accounts.DerivationPath, len(w.selfDeriveNextPath))
copy(path[:], w.selfDeriveNextPath[:])
account := accounts.Account{
Address: w.selfDeriveNextAddr,
URL: accounts.URL{Scheme: w.url.Scheme, Path: fmt.Sprintf("%s/%s", w.url.Path, path)},
}
_, known := w.paths[w.selfDeriveNextAddr]
if !known || (!empty && w.selfDeriveNextAddr == w.selfDerivePrevZero) {
// Either fully new account, or previous zero. Report discovery either way
glog.V(logger.Info).Infof("%s discovered %s (balance %d, nonce %d) at %s", w.url.String(), w.selfDeriveNextAddr.Hex(), balance, nonce, path)
}
if !known {
w.accounts = append(w.accounts, account)
w.paths[w.selfDeriveNextAddr] = path
}
// Fetch the next potential account
if !empty {
w.selfDeriveNextAddr = common.Address{}
w.selfDeriveNextPath[len(w.selfDeriveNextPath)-1]++
}
}
w.selfDeriveTime = time.Now()
// Return whatever account list we ended up with
cpy := make([]accounts.Account, len(w.accounts))
copy(cpy, w.accounts)
return cpy
@ -271,34 +356,16 @@ func (w *ledgerWallet) Contains(account accounts.Account) bool {
// Derive implements accounts.Wallet, deriving a new account at the specific
// derivation path. If pin is set to true, the account will be added to the list
// of tracked accounts.
func (w *ledgerWallet) Derive(path string, pin bool) (accounts.Account, error) {
func (w *ledgerWallet) Derive(path accounts.DerivationPath, pin bool) (accounts.Account, error) {
w.lock.Lock()
defer w.lock.Unlock()
// If the wallet is closed, or the Ethereum app doesn't run, abort
if w.device == nil || w.version == [3]byte{0, 0, 0} {
if w.device == nil || w.offline() {
return accounts.Account{}, accounts.ErrWalletClosed
}
// All seems fine, convert the user derivation path to Ledger representation
path = strings.TrimPrefix(path, "/")
parts := strings.Split(path, "/")
lpath := make([]uint32, len(parts))
for i, part := range parts {
// Handle hardened paths
if strings.HasSuffix(part, "'") {
lpath[i] = 0x80000000
part = strings.TrimSuffix(part, "'")
}
// Handle the non hardened component
val, err := strconv.Atoi(part)
if err != nil {
return accounts.Account{}, fmt.Errorf("path element %d: %v", i, err)
}
lpath[i] += uint32(val)
}
// Try to derive the actual account and update it's URL if succeeful
address, err := w.deriveAddress(lpath)
address, err := w.deriveAddress(path)
if err != nil {
return accounts.Account{}, err
}
@ -310,12 +377,27 @@ func (w *ledgerWallet) Derive(path string, pin bool) (accounts.Account, error) {
if pin {
if _, ok := w.paths[address]; !ok {
w.accounts = append(w.accounts, account)
w.paths[address] = lpath
w.paths[address] = path
}
}
return account, nil
}
// SelfDerive implements accounts.Wallet, trying to discover accounts that the
// user used previously (based on the chain state), but ones that he/she did not
// explicitly pin to the wallet manually. To avoid chain head monitoring, self
// derivation only runs during account listing (and even then throttled).
func (w *ledgerWallet) SelfDerive(base accounts.DerivationPath, chain ethereum.ChainStateReader) {
w.lock.Lock()
defer w.lock.Unlock()
w.selfDeriveNextPath = make(accounts.DerivationPath, len(base))
copy(w.selfDeriveNextPath[:], base[:])
w.selfDeriveNextAddr = common.Address{}
w.selfDeriveChain = chain
}
// SignHash implements accounts.Wallet, however signing arbitrary data is not
// supported for Ledger wallets, so this method will always return an error.
func (w *ledgerWallet) SignHash(acc accounts.Account, hash []byte) ([]byte, error) {