path: root/accounts/usbwallet/trezor.go

// 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/ava-labs/coreth/accounts"
	"github.com/ava-labs/coreth/accounts/usbwallet/trezor"
	"github.com/ava-labs/coreth/core/types"
	"github.com/ava-labs/go-ethereum/common"
	"github.com/ava-labs/go-ethereum/common/hexutil"
	"github.com/ava-labs/go-ethereum/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")

// ErrTrezorPassphraseNeeded is returned if opening the trezor requires a passphrase
var ErrTrezorPassphraseNeeded = errors.New("trezor: passphrase 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
	passphrasewait bool          // Flags whether the device is waiting for passphrase 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 or three phase operation:
//  * The first phase is to initialize the connection and read the wallet's
//    features. This phase is invoked if 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).
//  * If needed the device will ask for passphrase which will require calling
//    open again with the actual passphrase (3rd phase)
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 == "" && !w.passphrasewait {
		// 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 and Passphrase
		askPin := true
		askPassphrase := true
		res, err := w.trezorExchange(&trezor.Ping{PinProtection: &askPin, PassphraseProtection: &askPassphrase}, new(trezor.PinMatrixRequest), new(trezor.PassphraseRequest), new(trezor.Success))
		if err != nil {
			return err
		}
		// Only return the PIN request if the device wasn't unlocked until now
		switch res {
		case 0:
			w.pinwait = true
			return ErrTrezorPINNeeded
		case 1:
			w.pinwait = false
			w.passphrasewait = true
			return ErrTrezorPassphraseNeeded
		case 2:
			return nil // responded with trezor.Success
		}
	}
	// Phase 2 requested with actual PIN entry
	if w.pinwait {
		w.pinwait = false
		res, err := w.trezorExchange(&trezor.PinMatrixAck{Pin: &passphrase}, new(trezor.Success), new(trezor.PassphraseRequest))
		if err != nil {
			w.failure = err
			return err
		}
		if res == 1 {
			w.passphrasewait = true
			return ErrTrezorPassphraseNeeded
		}
	} else if w.passphrasewait {
		w.passphrasewait = false
		if _, err := w.trezorExchange(&trezor.PassphraseAck{Passphrase: &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
	}
	if addr := address.GetAddressBin(); len(addr) > 0 { // Older firmwares use binary fomats
		return common.BytesToAddress(addr), nil
	}
	if addr := address.GetAddressHex(); len(addr) > 0 { // Newer firmwares use hexadecimal fomats
		return common.HexToAddress(addr), nil
	}
	return common.Address{}, errors.New("missing derived address")
}

// 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 {
		// Non contract deploy, set recipient explicitly
		hex := to.Hex()
		request.ToHex = &hex     // Newer firmwares (old will ignore)
		request.ToBin = (*to)[:] // Older firmwares (new will ignore)
	}
	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 !=