// 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/>.
// This file contains the implementation for interacting with the Ledger hardware
// wallets. The wire protocol spec can be found in the Ledger Blue GitHub repo:
// https://raw.githubusercontent.com/LedgerHQ/blue-app-eth/master/doc/ethapp.asc
// +build !ios
package usbwallet
import (
"encoding/binary"
"encoding/hex"
"errors"
"fmt"
"io"
"math/big"
"strconv"
"strings"
"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/logger"
"github.com/ethereum/go-ethereum/logger/glog"
"github.com/ethereum/go-ethereum/rlp"
"github.com/karalabe/gousb/usb"
)
// ledgerDeviceIDs are the known device IDs that Ledger wallets use.
var ledgerDeviceIDs = []deviceID{
{Vendor: 0x2c97, Product: 0x0000}, // Ledger Blue
{Vendor: 0x2c97, Product: 0x0001}, // Ledger Nano S
}
// ledgerDerivationPath is the key derivation parameters used by the wallet.
var ledgerDerivationPath = [4]uint32{0x80000000 + 44, 0x80000000 + 60, 0x80000000 + 0, 0}
// ledgerOpcode is an enumeration encoding the supported Ledger opcodes.
type ledgerOpcode byte
// ledgerParam1 is an enumeration encoding the supported Ledger parameters for
// specific opcodes. The same parameter values may be reused between opcodes.
type ledgerParam1 byte
// ledgerParam2 is an enumeration encoding the supported Ledger parameters for
// specific opcodes. The same parameter values may be reused between opcodes.
type ledgerParam2 byte
const (
ledgerOpRetrieveAddress ledgerOpcode = 0x02 // Returns the public key and Ethereum address for a given BIP 32 path
ledgerOpSignTransaction ledgerOpcode = 0x04 // Signs an Ethereum transaction after having the user validate the parameters
ledgerOpGetConfiguration ledgerOpcode = 0x06 // Returns specific wallet application configuration
ledgerP1DirectlyFetchAddress ledgerParam1 = 0x00 // Return address directly from the wallet
ledgerP1ConfirmFetchAddress ledgerParam1 = 0x01 // Require a user confirmation before returning the address
ledgerP1InitTransactionData ledgerParam1 = 0x00 // First transaction data block for signing
ledgerP1ContTransactionData ledgerParam1 = 0x80 // Subsequent transaction data block for signing
ledgerP2DiscardAddressChainCode ledgerParam2 = 0x00 // Do not return the chain code along with the address
ledgerP2ReturnAddressChainCode ledgerParam2 = 0x01 // Require a user confirmation before returning the address
)
// ledgerWallet represents a live USB Ledger hardware wallet.
type ledgerWallet struct {
device *usb.Device // USB device advertising itself as a Ledger wallet
input usb.Endpoint // Input endpoint to send data to this device
output usb.Endpoint // Output endpoint to receive data from this device
address common.Address // Current address of the wallet (may be zero if Ethereum app offline)
url string // Textual URL uniquely identifying this wallet
version [3]byte // Current version of the Ledger Ethereum app (zero if app is offline)
}
// LedgerHub is a USB hardware wallet interface that can find and handle Ledger
// wallets.
type LedgerHub struct {
ctx *usb.Context // Context interfacing with a libusb instance
wallets map[uint16]*ledgerWallet // Apparent Ledger wallets (some may be inactive)
accounts []accounts.Account // List of active Ledger accounts
index map[common.Address]uint16 // Set of addresses with active wallets
quit chan chan error
lock sync.RWMutex
}
// NewLedgerHub creates a new hardware wallet manager for Ledger devices.
func NewLedgerHub() (*LedgerHub, error) {
// Initialize the USB library to access Ledgers through
ctx, err := usb.NewContext()
if err != nil {
return nil, err
}
// Create the USB hub, start and return it
hub := &LedgerHub{
ctx: ctx,
wallets: make(map[uint16]*ledgerWallet),
index: make(map[common.Address]uint16),
quit: make(chan chan error),
}
go hub.watch()
return hub, nil
}
// Accounts retrieves the live of accounts currently known by the Ledger hub.
func (hub *LedgerHub) Accounts() []accounts.Account {
hub.lock.RLock()
defer hub.lock.RUnlock()
cpy := make([]accounts.Account, len(hub.accounts))
copy(cpy, hub.accounts)
return cpy
}
// HasAddress reports whether an account with the given address is present.
func (hub *LedgerHub) HasAddress(addr common.Address) bool {
hub.lock.RLock()
defer hub.lock.RUnlock()
_, known := hub.index[addr]
return known
}
// SignHash is not supported for Ledger wallets, so this method will always
// return an error.
func (hub *LedgerHub) SignHash(acc accounts.Account, hash []byte) ([]byte, error) {
return nil, accounts.ErrNotSupported
}
// SignTx sends the transaction over to the Ledger wallet to request a confirmation
// from the user. It returns either the signed transaction or a failure if the user
// denied the transaction.
//
// Note, if the version of the Ethereum application running on the Ledger wallet is
// too old to sign EIP-155 transactions, but such is requested nonetheless, an error
// will be returned opposed to silently signing in Homestead mode.
func (hub *LedgerHub) SignTx(acc accounts.Account, tx *types.Transaction, chainID *big.Int) (*types.Transaction, error) {
hub.lock.RLock()
defer hub.lock.RUnlock()
// If the account contains the device URL, flatten it to make sure
var id uint16
if acc.URL != "" {
if parts := strings.Split(acc.URL, "."); len(parts) == 2 {
bus, busErr := strconv.Atoi(parts[0])
addr, addrErr := strconv.Atoi(parts[1])
if busErr == nil && addrErr == nil {
id = uint16(bus)<<8 + uint16(addr)
}
}
}
// If the id is still zero, URL is either missing or bad, resolve
if id == 0 {
var ok bool
if id, ok = hub.index[acc.Address]; !ok {
return nil, accounts.ErrUnknownAccount
}
}
// Retrieve the wallet associated with the URL
wallet, ok := hub.wallets[id]
if !ok {
return nil, accounts.ErrUnknownAccount
}
// Ensure the wallet is capable of signing the given transaction
if chainID != nil && wallet.version[0] <= 1 && wallet.version[1] <= 0 && wallet.version[2] <= 2 {
return nil, fmt.Errorf("Ledger v%d.%d.%d doesn't support signing this transaction, please update to v1.0.3 at least",
wallet.version[0], wallet.version[1], wallet.version[2])
}
return wallet.sign(tx, chainID)
}
// SignHashWithPassphrase is not supported for Ledger wallets, so this method
// will always return an error.
func (hub *LedgerHub) SignHashWithPassphrase(acc accounts.Account, passphrase string, hash []byte) ([]byte, error) {
return nil, accounts.ErrNotSupported
}
// SignTxWithPassphrase requests the backend to sign the given transaction, with the
// given passphrase as extra authentication information. Since the Ledger does not
// support this feature, it will just silently ignore the passphrase.
func (hub *LedgerHub) SignTxWithPassphrase(acc accounts.Account, passphrase string, tx *types.Transaction, chainID *big.Int) (*types.Transaction, error) {
return hub.SignTx(acc, tx, chainID)
}
// Close terminates the usb watching for Ledger wallets and returns when it
// successfully terminated.
func (hub *LedgerHub) Close() error {
// Terminate the USB scanner
errc := make(chan error)
hub.quit <- errc
err := <-errc
// Release the USB interface and return
hub.ctx.Close()
return err
}
// watch starts watching the local machine's USB ports for the connection or
// disconnection of Ledger devices.
func (hub *LedgerHub) watch() {
for {
// Rescan the USB ports for devices newly added or removed
hub.rescan()
// Sleep for a certain amount of time or until terminated
select {
case errc := <-hub.quit:
errc <- nil
return
case <-time.After(time.Second):
}
}
}
// rescan searches the USB ports for attached Ledger hardware wallets.
func (hub *LedgerHub) rescan() {
hub.lock.Lock()
defer hub.lock.Unlock()
// Iterate over all connected Ledger devices and do a heartbeat test
for id, wallet := range hub.wallets {
// If the device doesn't respond (io error on Windows, no device on Linux), drop
if err := wallet.resolveVersion(); err == usb.ERROR_IO || err == usb.ERROR_NO_DEVICE {
// Wallet disconnected or at least in a useless state
if wallet.address == (common.Address{}) {
glog.V(logger.Info).Infof("ledger wallet [%03d.%03d] disconnected", wallet.device.Bus, wallet.device.Address)
} else {
// A live account disconnected, remove it from the tracked accounts
for i, account := range hub.accounts {
if account.Address == wallet.address && account.URL == wallet.url {
hub.accounts = append(hub.accounts[:i], hub.accounts[i+1:]...)
break
}
}
delete(hub.index, wallet.address)
glog.V(logger.Info).Infof("ledger wallet [%03d.%03d] v%d.%d.%d disconnected: %s", wallet.device.Bus, wallet.device.Address,
wallet.version[0], wallet.version[1], wallet.version[2], wallet.address.Hex())
}
delete(hub.wallets, id)
wallet.device.Close()
}
}
// Iterate over all attached devices and fetch those seemingly Ledger
devices, _ := hub.ctx.ListDevices(func(desc *usb.Descriptor) bool {
// Discard all devices not advertizing as Ledger
ledger := false
for _, id := range ledgerDeviceIDs {
if desc.Vendor == id.Vendor && desc.Product == id.Product {
ledger = true
}
}
if !ledger {
return false
}
// If we have an already known Ledger, skip opening it
id := uint16(desc.Bus)<<8 + uint16(desc.Address)
if _, known := hub.wallets[id]; known {
return false
}
// New Ledger device, open it for communication
return true
})
// Start tracking all wallets which newly appeared
var err error
for _, device := range devices {
// Make sure the alleged device has the correct IO endpoints
wallet := &ledgerWallet{
device: device,
url: fmt.Sprintf("%03d.%03d", device.Bus, device.Address),
}
var invalid string
switch {
case len(device.Descriptor.Configs) == 0:
invalid = "no endpoint config available"
case len(device.Descriptor.Configs[0].Interfaces) == 0:
invalid = "no endpoint interface available"
case len(device.Descriptor.Configs[0].Interfaces[0].Setups) == 0:
invalid = "no endpoint setup available"
case len(device.Descriptor.Configs[0].Interfaces[0].Setups[0].Endpoints) < 2:
invalid = "not enough IO endpoints available"
}
if invalid != "" {
glog.V(logger.Debug).Infof("ledger wallet [%s] deemed invalid: %s", wallet.url, invalid)
device.Close()
continue
}
// Open the input and output endpoints to the device
wallet.input, err = device.OpenEndpoint(
device.Descriptor.Configs[0].Config,
device.Descriptor.Configs[0].Interfaces[0].Number,
device.Descriptor.Configs[0].Interfaces[0].Setups[0].Number,
device.Descriptor.Configs[0].Interfaces[0].Setups[0].Endpoints[1].Address,
)
if err != nil {
glog.V(logger.Debug).Infof("ledger wallet [%s] input open failed: %v", wallet.url, err)
device.Close()
continue
}
wallet.output, err = device.OpenEndpoint(
device.Descriptor.Configs[0].Config,
device.Descriptor.Configs[0].Interfaces[0].Number,
device.Descriptor.Configs[0].Interfaces[0].Setups[0].Number,
device.Descriptor.Configs[0].Interfaces[0].Setups[0].Endpoints[0].Address,
)
if err != nil {
glog.V(logger.Debug).Infof("ledger wallet [%s] output open failed: %v", wallet.url, err)
device.Close()
continue
}
// Start tracking the device as a probably Ledger wallet
id := uint16(device.Bus)<<8 + uint16(device.Address)
hub.wallets[id] = wallet
if wallet.resolveAddress() != nil {
glog.V(logger.Info).Infof("ledger wallet [%s] connected, Ethereum app not started", wallet.url)
} else {
// Try to resolve the Ethereum app's version, will fail prior to v1.0.2
if wallet.resolveVersion() != nil {
wallet.version = [3]byte{1, 0, 0} // Assume worst case, can't verify if v1.0.0 or v1.0.1
}
hub.accounts = append(hub.accounts, accounts.Account{
Address: wallet.address,
URL: wallet.url,
})
hub.index[wallet.address] = id
glog.V(logger.Info).Infof("ledger wallet [%s] v%d.%d.%d connected: %s", wallet.url,
wallet.version[0], wallet.version[1], wallet.version[2], wallet.address.Hex())
}
}
}
// resolveVersion retrieves the current version of the Ethereum wallet app running
// on the Ledger wallet and caches it for future reference.
//
// The version retrieval protocol is defined as follows:
//
// CLA | INS | P1 | P2 | Lc | Le
// ----+-----+----+----+----+---
// E0 | 06 | 00 | 00 | 00 | 04
//
// With no input data, and the output data being:
//
// Description | Length
// ---------------------------------------------------+--------
// Flags 01: arbitrary data signature enabled by user | 1 byte
// Application major version | 1 byte
// Application minor version | 1 byte
// Application patch version | 1 byte
func (wallet *ledgerWallet) resolveVersion() error {
// Send the request and wait for the response
reply, err := wallet.exchange(ledgerOpGetConfiguration, 0, 0, nil)
if err != nil {
return err
}
if len(reply) != 4 {
return errors.New("reply not of correct size")
}
// Cache the version for future reference
copy(wallet.version[:], reply[1:])
return nil
}
// resolveAddress retrieves the currently active Ethereum address from a Ledger
// wallet and caches it for future reference.
//
// The address derivation protocol is defined as follows:
//
// CLA | INS | P1 | P2 | Lc | Le
// ----+-----+----+----+-----+---
// E0 | 02 | 00 return address
// 01 display address and confirm before returning
// | 00: do not return the chain code
// | 01: return the chain code
// | var | 00
//
// Where the input data is:
//
// Description | Length
// -------------------------------------------------+--------
// Number of BIP 32 derivations to perform (max 10) | 1 byte
// First derivation index (big endian) | 4 bytes
// ... | 4 bytes
// Last derivation index (big endian) | 4 bytes
//
// And the output data is:
//
// Description | Length
// ------------------------+-------------------
// Public Key length | 1 byte
// Uncompressed Public Key | arbitrary
// Ethereum address length | 1 byte
// Ethereum address | 40 bytes hex ascii
// Chain code if requested | 32 bytes
func (wallet *ledgerWallet) resolveAddress() error {
// Flatten the derivation path into the Ledger request
path := make([]byte, 1+4*len(ledgerDerivationPath))
path[0] = byte(len(ledgerDerivationPath))
for i, component := range ledgerDerivationPath {
binary.BigEndian.PutUint32(path[1+4*i:], component)
}
// Send the request and wait for the response
reply, err := wallet.exchange(ledgerOpRetrieveAddress, ledgerP1DirectlyFetchAddress, ledgerP2DiscardAddressChainCode, path)
if err != nil {
return err
}
// Discard the public key, we don't need that for now
if len(reply) < 1 || len(reply) < 1+int(reply[0]) {
return errors.New("reply lacks public key entry")
}
reply = reply[1+int(reply[0]):]
// Extract the Ethereum hex address string
if len(reply) < 1 || len(reply) < 1+int(reply[0]) {
return errors.New("reply lacks address entry")
}
hexstr := reply[1 : 1+int(reply[0])]
// Decode the hex sting into an Ethereum address and return
hex.Decode(wallet.address[:], hexstr)
return nil
}
// sign sends the transaction to the Ledger wallet, and waits for the user to
// confirm or deny the transaction.
//
// The transaction signing protocol is defined as follows:
//
// CLA | INS | P1 | P2 | Lc | Le
// ----+-----+----+----+-----+---
// E0 | 04 | 00: first transaction data block
// 80: subsequent transaction data block
// | 00 | variable | variable
//
// Where the input for the first transaction block (first 255 bytes) is:
//
// Description | Length
// -------------------------------------------------+----------
// Number of BIP 32 derivations to perform (max 10) | 1 byte
// First derivation index (big endian) | 4 bytes
// ... | 4 bytes
// Last derivation index (big endian) | 4 bytes
// RLP transaction chunk | arbitrary
//
// And the input for subsequent transaction blocks (first 255 bytes) are:
//
// Description | Length
// ----------------------+----------
// RLP transaction chunk | arbitrary
//
// And the output data is:
//
// Description | Length
// ------------+---------
// signature V | 1 byte
// signature R | 32 bytes
// signature S | 32 bytes
func (wallet *ledgerWallet) sign(tx *types.Transaction, chainID *big.Int) (*types.Transaction, error) {
// We need to modify the timeouts to account for user feedback
defer func(old time.Duration) { wallet.device.ReadTimeout = old }(wallet.device.ReadTimeout)
wallet.device.ReadTimeout = time.Minute
// Flatten the derivation path into the Ledger request
path := make([]byte, 1+4*len(ledgerDerivationPath))
path[0] = byte(len(ledgerDerivationPath))
for i, component := range ledgerDerivationPath {
binary.BigEndian.PutUint32(path[1+4*i:], component)
}
// Create the transaction RLP based on whether legacy or EIP155 signing was requeste
var (
txrlp []byte
err error
)
if chainID == nil {
if txrlp, err = rlp.EncodeToBytes([]interface{}{tx.Nonce(), tx.GasPrice(), tx.Gas(), tx.To(), tx.Value(), tx.Data()}); err != nil {
return nil, err
}
} else {
if txrlp, err = rlp.EncodeToBytes([]interface{}{tx.Nonce(), tx.GasPrice(), tx.Gas(), tx.To(), tx.Value(), tx.Data(), chainID, big.NewInt(0), big.NewInt(0)}); err != nil {
return nil, err
}
}
payload := append(path, txrlp...)
// Send the request and wait for the response
var (
op = ledgerP1InitTransactionData
reply []byte
)
for len(payload) > 0 {
// Calculate the size of the next data chunk
chunk := 255
if chunk > len(payload) {
chunk = len(payload)
}
// Send the chunk over, ensuring it's processed correctly
reply, err = wallet.exchange(ledgerOpSignTransaction, op, 0, payload[:chunk])
if err != nil {
return nil, err
}
// Shift the payload and ensure subsequent chunks are marked as such
payload = payload[chunk:]
op = ledgerP1ContTransactionData
}
// Extract the Ethereum signature and do a sanity validation
if len(reply) != 65 {
return nil, errors.New("reply lacks signature")
}
signature := append(reply[1:], reply[0])
// Create the correct signer and signature transform based on the chain ID
var signer types.Signer
if chainID == nil {
signer = new(types.HomesteadSigner)
} else {
signer = types.NewEIP155Signer(chainID)
signature[64] = (signature[64]-34)/2 - byte(chainID.Uint64())
}
// Inject the final signature into the transaction and sanity check the sender
signed, err := tx.WithSignature(signer, signature)
if err != nil {
return nil, err
}
sender, err := types.Sender(signer, signed)
if err != nil {
return nil, err
}
if sender != wallet.address {
glog.V(logger.Error).Infof("Ledger signer mismatch: expected %s, got %s", wallet.address.Hex(), sender.Hex())
return nil, fmt.Errorf("signer mismatch: expected %s, got %s", wallet.address.Hex(), sender.Hex())
}
return signed, nil
}
// exchange performs a data exchange with the Ledger wallet, sending it a message
// and retrieving the response.
//
// The common transport header is defined as follows:
//
// Description | Length
// --------------------------------------+----------
// Communication channel ID (big endian) | 2 bytes
// Command tag | 1 byte
// Packet sequence index (big endian) | 2 bytes
// Payload | arbitrary
//
// The Communication channel ID allows commands multiplexing over the same
// physical link. It is not used for the time being, and should be set to 0101
// to avoid compatibility issues with implementations ignoring a leading 00 byte.
//
// The Command tag describes the message content. Use TAG_APDU (0x05) for standard
// APDU payloads, or TAG_PING (0x02) for a simple link test.
//
// The Packet sequence index describes the current sequence for fragmented payloads.
// The first fragment index is 0x00.
//
// APDU Command payloads are encoded as follows:
//
// Description | Length
// -----------------------------------
// APDU length (big endian) | 2 bytes
// APDU CLA | 1 byte
// APDU INS | 1 byte
// APDU P1 | 1 byte
// APDU P2 | 1 byte
// APDU length | 1 byte
// Optional APDU data | arbitrary
func (wallet *ledgerWallet) exchange(opcode ledgerOpcode, p1 ledgerParam1, p2 ledgerParam2, data []byte) ([]byte, error) {
// Construct the message payload, possibly split into multiple chunks
var chunks [][]byte
for left := data; len(left) > 0 || len(chunks) == 0; {
// Create the chunk header
var chunk []byte
if len(chunks) == 0 {
// The first chunk encodes the length and all the opcodes
chunk = []byte{0x00, 0x00, 0xe0, byte(opcode), byte(p1), byte(p2), byte(len(data))}
binary.BigEndian.PutUint16(chunk, uint16(5+len(data)))
}
// Append the data blob to the end of the chunk
space := 64 - len(chunk) - 5 // 5 == header size
if len(left) > space {
chunks, left = append(chunks, append(chunk, left[:space]...)), left[space:]
continue
}
chunks, left = append(chunks, append(chunk, left...)), nil
}
// Stream all the chunks to the device
for i, chunk := range chunks {
// Construct the new message to stream
header := []byte{0x01, 0x01, 0x05, 0x00, 0x00} // Channel ID and command tag appended
binary.BigEndian.PutUint16(header[3:], uint16(i))
msg := append(header, chunk...)
// Send over to the device
if glog.V(logger.Core) {
glog.Infof("-> %03d.%03d: %x", wallet.device.Bus, wallet.device.Address, msg)
}
if _, err := wallet.input.Write(msg); err != nil {
return nil, err
}
}
// Stream the reply back from the wallet in 64 byte chunks
var reply []byte
for {
// Read the next chunk from the Ledger wallet
chunk := make([]byte, 64)
if _, err := io.ReadFull(wallet.output, chunk); err != nil {
return nil, err
}
if glog.V(logger.Core) {
glog.Infof("<- %03d.%03d: %x", wallet.device.Bus, wallet.device.Address, chunk)
}
// Make sure the transport header matches
if chunk[0] != 0x01 || chunk[1] != 0x01 || chunk[2] != 0x05 {
return nil, fmt.Errorf("invalid reply header: %x", chunk[:3])
}
// If it's the first chunk, retrieve the total message length
if chunk[3] == 0x00 && chunk[4] == 0x00 {
reply = make([]byte, 0, int(binary.BigEndian.Uint16(chunk[5:7])))
chunk = chunk[7:]
} else {
chunk = chunk[5:]
}
// Append to the reply and stop when filled up
if left := cap(reply) - len(reply); left > len(chunk) {
reply = append(reply, chunk...)
} else {
reply = append(reply, chunk[:left]...)
break
}
}
return reply[:len(reply)-2], nil
}
