// 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 Trezor hardware
// wallets. The wire protocol spec can be found on the SatoshiLabs website:
// https://doc.satoshilabs.com/trezor-tech/api-protobuf.html
package usbwallet
import (
"encoding/binary"
"errors"
"fmt"
"io"
"math/big"
"github.com/dexon-foundation/dexon/accounts"
"github.com/dexon-foundation/dexon/accounts/usbwallet/internal/trezor"
"github.com/dexon-foundation/dexon/common"
"github.com/dexon-foundation/dexon/common/hexutil"
"github.com/dexon-foundation/dexon/core/types"
"github.com/dexon-foundation/dexon/log"
"github.com/golang/protobuf/proto"
)
// ErrTrezorPINNeeded is returned if opening the trezor requires a PIN code. In
// this case, the calling application should display a pinpad and send back the
// encoded passphrase.
var ErrTrezorPINNeeded = errors.New("trezor: pin needed")
// errTrezorReplyInvalidHeader is the error message returned by a Trezor data exchange
// if the device replies with a mismatching header. This usually means the device
// is in browser mode.
var errTrezorReplyInvalidHeader = errors.New("trezor: invalid reply header")
// trezorDriver implements the communication with a Trezor hardware wallet.
type trezorDriver struct {
device io.ReadWriter // USB device connection to communicate through
version [3]uint32 // Current version of the Trezor firmware
label string // Current textual label of the Trezor device
pinwait bool // Flags whether the device is waiting for PIN entry
failure error // Any failure that would make the device unusable
log log.Logger // Contextual logger to tag the trezor with its id
}
// newTrezorDriver creates a new instance of a Trezor USB protocol driver.
func newTrezorDriver(logger log.Logger) driver {
return &trezorDriver{
log: logger,
}
}
// Status implements accounts.Wallet, always whether the Trezor is opened, closed
// or whether the Ethereum app was not started on it.
func (w *trezorDriver) Status() (string, error) {
if w.failure != nil {
return fmt.Sprintf("Failed: %v", w.failure), w.failure
}
if w.device == nil {
return "Closed", w.failure
}
if w.pinwait {
return fmt.Sprintf("Trezor v%d.%d.%d '%s' waiting for PIN", w.version[0], w.version[1], w.version[2], w.label), w.failure
}
return fmt.Sprintf("Trezor v%d.%d.%d '%s' online", w.version[0], w.version[1], w.version[2], w.label), w.failure
}
// Open implements usbwallet.driver, attempting to initialize the connection to
// the Trezor hardware wallet. Initializing the Trezor is a two phase operation:
// * The first phase is to initialize the connection and read the wallet's
// features. This phase is invoked is the provided passphrase is empty. The
// device will display the pinpad as a result and will return an appropriate
// error to notify the user that a second open phase is needed.
// * The second phase is to unlock access to the Trezor, which is done by the
// user actually providing a passphrase mapping a keyboard keypad to the pin
// number of the user (shuffled according to the pinpad displayed).
func (w *trezorDriver) Open(device io.ReadWriter, passphrase string) error {
w.device, w.failure = device, nil
// If phase 1 is requested, init the connection and wait for user callback
if passphrase == "" {
// If we're already waiting for a PIN entry, insta-return
if w.pinwait {
return ErrTrezorPINNeeded
}
// Initialize a connection to the device
features := new(trezor.Features)
if _, err := w.trezorExchange(&trezor.Initialize{}, features); err != nil {
return err
}
w.version = [3]uint32{features.GetMajorVersion(), features.GetMinorVersion(), features.GetPatchVersion()}
w.label = features.GetLabel()
// Do a manual ping, forcing the device to ask for its PIN
askPin := true
res, err := w.trezorExchange(&trezor.Ping{PinProtection: &askPin}, new(trezor.PinMatrixRequest), new(trezor.Success))
if err != nil {
return err
}
// Only return the PIN request if the device wasn't unlocked until now
if res == 1 {
return nil // Device responded with trezor.Success
}
w.pinwait = true
return ErrTrezorPINNeeded
}
// Phase 2 requested with actual PIN entry
w.pinwait = false
if _, err := w.trezorExchange(&trezor.PinMatrixAck{Pin: &passphrase}, new(trezor.Success)); err != nil {
w.failure = err
return err
}
return nil
}
// Close implements usbwallet.driver, cleaning up and metadata maintained within
// the Trezor driver.
func (w *trezorDriver) Close() error {
w.version, w.label, w.pinwait = [3]uint32{}, "", false
return nil
}
// Heartbeat implements usbwallet.driver, performing a sanity check against the
// Trezor to see if it's still online.
func (w *trezorDriver) Heartbeat() error {
if _, err := w.trezorExchange(&trezor.Ping{}, new(trezor.Success)); err != nil {
w.failure = err
return err
}
return nil
}
// Derive implements usbwallet.driver, sending a derivation request to the Trezor
// and returning the Ethereum address located on that derivation path.
func (w *trezorDriver) Derive(path accounts.DerivationPath) (common.Address, error) {
return w.trezorDerive(path)
}
// SignTx implements usbwallet.driver, sending the transaction to the Trezor and
// waiting for the user to confirm or deny the transaction.
func (w *trezorDriver) SignTx(path accounts.DerivationPath, tx *types.Transaction, chainID *big.Int) (common.Address, *types.Transaction, error) {
if w.device == nil {
return common.Address{}, nil, accounts.ErrWalletClosed
}
return w.trezorSign(path, tx, chainID)
}
// trezorDerive sends a derivation request to the Trezor device and returns the
// Ethereum address located on that path.
func (w *trezorDriver) trezorDerive(derivationPath []uint32) (common.Address, error) {
address := new(trezor.EthereumAddress)
if _, err := w.trezorExchange(&trezor.EthereumGetAddress{AddressN: derivationPath}, address); err != nil {
return common.Address{}, err
}
return common.BytesToAddress(address.GetAddress()), nil
}
// trezorSign sends the transaction to the Trezor wallet, and waits for the user
// to confirm or deny the transaction.
func (w *trezorDriver) trezorSign(derivationPath []uint32, tx *types.Transaction, chainID *big.Int) (common.Address, *types.Transaction, error) {
// Create the transaction initiation message
data := tx.Data()
length := uint32(len(data))
request := &trezor.EthereumSignTx{
AddressN: derivationPath,
Nonce: new(big.Int).SetUint64(tx.Nonce()).Bytes(),
GasPrice: tx.GasPrice().Bytes(),
GasLimit: new(big.Int).SetUint64(tx.Gas()).Bytes(),
Value: tx.Value().Bytes(),
DataLength: &length,
}
if to := tx.To(); to != nil {
request.To = (*to)[:] // Non contract deploy, set recipient explicitly
}
if length > 1024 { // Send the data chunked if that was requested
request.DataInitialChunk, data = data[:1024], data[1024:]
} else {
request.DataInitialChunk, data = data, nil
}
if chainID != nil { // EIP-155 transaction, set chain ID explicitly (only 32 bit is supported!?)
id := uint32(chainID.Int64())
request.ChainId = &id
}
// Send the initiation message and stream content until a signature is returned
response := new(trezor.EthereumTxRequest)
if _, err := w.trezorExchange(request, response); err != nil {
return common.Address{}, nil, err
}
for response.DataLength != nil && int(*response.DataLength) <= len(data) {
chunk := data[:*response.DataLength]
data = data[*response.DataLength:]
if _, err := w.trezorExchange(&trezor.EthereumTxAck{DataChunk: chunk}, response); err != nil {
return common.Address{}, nil, err
}
}
// Extract the Ethereum signature and do a sanity validation
if len(response.GetSignatureR()) == 0 || len(response.GetSignatureS()) == 0 || response.GetSignatureV() == 0 {
return common.Address{}, nil, errors.New("reply lacks signature")
}
signature := append(append(response.GetSignatureR(), response.GetSignatureS()...), byte(response.GetSignatureV()))
// 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] -= byte(chainID.Uint64()*2 + 35)
}
// Inject the final signature into the transaction and sanity check the sender
signed, err := tx.WithSignature(signer, signature)
if err != nil {
return common.Address{}, nil, err
}
sender, err := types.Sender(signer, signed)
if err != nil {
return common.Address{}, nil, err
}
return sender, signed, nil
}
// trezorExchange performs a data exchange with the Trezor wallet, sending it a
// message and retrieving the response. If multiple responses are possible, the
// method will also return the index of the destination object used.
func (w *trezorDriver) trezorExchange(req proto.Message, results ...proto.Message) (int, error) {
// Construct the original message payload to chunk up
data, err := proto.Marshal(req)
if err != nil {
return 0, err
}
payload := make([]byte, 8+len(data))
copy(payload, []byte{0x23, 0x23})
binary.BigEndian.PutUint16(payload[2:], trezor.Type(req))
binary.BigEndian.PutUint32(payload[4:], uint32(len(data)))
copy(payload[8:], data)
// Stream all the chunks to the device
chunk := make([]byte, 64)
chunk[0] = 0x3f // Report ID magic number
for len(payload) > 0 {
// Construct the new message to stream, padding with zeroes if needed
if len(payload) > 63 {
copy(chunk[1:], payload[:63])
payload = payload[63:]
} else {
copy(chunk[1:], payload)
copy(chunk[1+len(payload):], make([]byte, 63-len(payload)))
payload = nil
}
// Send over to the device
w.log.Trace("Data chunk sent to the Trezor", "chunk", hexutil.Bytes(chunk))
if _, err := w.device.Write(chunk); err != nil {
return 0, err
}
}
// Stream the reply back from the wallet in 64 byte chunks
var (
kind uint16
reply []byte
)
for {
// Read the next chunk from the Trezor wallet
if _, err := io.ReadFull(w.device, chunk); err != nil {
return 0, err
}
w.log.Trace("Data chunk received from the Trezor", "chunk", hexutil.Bytes(chunk))
// Make sure the transport header matches
if chunk[0] != 0x3f || (len(reply) == 0 && (chunk[1] != 0x23 || chunk[2] != 0x23)) {
return 0, errTrezorReplyInvalidHeader
}
// If it's the first chunk, retrieve the reply message type and total message length
var payload []byte
if len(reply) == 0 {
kind = binary.BigEndian.Uint16(chunk[3:5])
reply = make([]byte, 0, int(binary.BigEndian.Uint32(chunk[5:9])))
payload = chunk[9:]
} else {
payload = chunk[1:]
}
// Append to the reply and stop when filled up
if left := cap(reply) - len(reply); left > len(payload) {
reply = append(reply, payload...)
} else {
reply = append(reply, payload[:left]...)
break
}
}
// Try to parse the reply into the requested reply message
if kind == uint16(trezor.MessageType_MessageType_Failure) {
// Trezor returned a failure, extract and return the message
failure := new(trezor.Failure)
if err := proto.Unmarshal(reply, failure); err != nil {
return 0, err
}
return 0, errors.New("trezor: " + failure.GetMessage())
}
if kind == uint16(trezor.MessageType_MessageType_ButtonRequest) {
// Trezor is waiting for user confirmation, ack and wait for the next message
return w.trezorExchange(&trezor.ButtonAck{}, results...)
}
for i, res := range results {
if trezor.Type(res) == kind {
return i, proto.Unmarshal(reply, res)
}
}
expected := make([]string, len(results))
for i, res := range results {
expected[i] = trezor.Name(trezor.Type(res))
}
return 0, fmt.Errorf("trezor: expected reply types %s, got %s", expected, trezor.Name(kind))
}
