pallectrum/electrum/plugins/ledger/ledger.py

from struct import pack, unpack
import hashlib
import sys
import traceback
from typing import Optional, Tuple

from electrum import ecc
from electrum import bip32
from electrum.crypto import hash_160
from electrum.bitcoin import int_to_hex, var_int, is_segwit_script_type
from electrum.bip32 import BIP32Node, convert_bip32_intpath_to_strpath
from electrum.i18n import _
from electrum.keystore import Hardware_KeyStore
from electrum.transaction import Transaction, PartialTransaction, PartialTxInput, PartialTxOutput
from electrum.wallet import Standard_Wallet
from electrum.util import bfh, bh2u, versiontuple, UserFacingException
from electrum.base_wizard import ScriptTypeNotSupported
from electrum.logging import get_logger

from ..hw_wallet import HW_PluginBase, HardwareClientBase
from ..hw_wallet.plugin import is_any_tx_output_on_change_branch, validate_op_return_output, LibraryFoundButUnusable


_logger = get_logger(__name__)


try:
    import hid
    from btchip.btchipComm import HIDDongleHIDAPI, DongleWait
    from btchip.btchip import btchip
    from btchip.btchipUtils import compress_public_key,format_transaction, get_regular_input_script, get_p2sh_input_script
    from btchip.bitcoinTransaction import bitcoinTransaction
    from btchip.btchipFirmwareWizard import checkFirmware, updateFirmware
    from btchip.btchipException import BTChipException
    BTCHIP = True
    BTCHIP_DEBUG = False
except ImportError:
    BTCHIP = False

MSG_NEEDS_FW_UPDATE_GENERIC = _('Firmware version too old. Please update at') + \
                      ' https://www.ledgerwallet.com'
MSG_NEEDS_FW_UPDATE_SEGWIT = _('Firmware version (or "Bitcoin" app) too old for Segwit support. Please update at') + \
                      ' https://www.ledgerwallet.com'
MULTI_OUTPUT_SUPPORT = '1.1.4'
SEGWIT_SUPPORT = '1.1.10'
SEGWIT_SUPPORT_SPECIAL = '1.0.4'
SEGWIT_TRUSTEDINPUTS = '1.4.0'


def test_pin_unlocked(func):
    """Function decorator to test the Ledger for being unlocked, and if not,
    raise a human-readable exception.
    """
    def catch_exception(self, *args, **kwargs):
        try:
            return func(self, *args, **kwargs)
        except BTChipException as e:
            if e.sw == 0x6982:
                raise UserFacingException(_('Your Ledger is locked. Please unlock it.'))
            else:
                raise
    return catch_exception


class Ledger_Client(HardwareClientBase):
    def __init__(self, hidDevice, *, product_key: Tuple[int, int],
                 plugin: HW_PluginBase):
        HardwareClientBase.__init__(self, plugin=plugin)
        self.dongleObject = btchip(hidDevice)
        self.preflightDone = False
        self._product_key = product_key
        self._soft_device_id = None

    def is_pairable(self):
        return True

    def close(self):
        with self.device_manager().hid_lock:
            self.dongleObject.dongle.close()

    def timeout(self, cutoff):
        pass

    def is_initialized(self):
        return True

    def get_soft_device_id(self):
        if self._soft_device_id is None:
            # modern ledger can provide xpub without user interaction
            # (hw1 would prompt for PIN)
            if not self.is_hw1():
                self._soft_device_id = self.request_root_fingerprint_from_device()
        return self._soft_device_id

    def is_hw1(self) -> bool:
        return self._product_key[0] == 0x2581

    def device_model_name(self):
        if self.is_hw1():
            return "Ledger HW.1"
        if self._product_key == (0x2c97, 0x0000):
            return "Ledger Blue"
        if self._product_key == (0x2c97, 0x0001):
            return "Ledger Nano S"
        if self._product_key == (0x2c97, 0x0004):
            return "Ledger Nano X"
        return None

    def has_usable_connection_with_device(self):
        try:
            self.dongleObject.getFirmwareVersion()
        except BaseException:
            return False
        return True

    @test_pin_unlocked
    def get_xpub(self, bip32_path, xtype):
        self.checkDevice()
        # bip32_path is of the form 44'/0'/1'
        # S-L-O-W - we don't handle the fingerprint directly, so compute
        # it manually from the previous node
        # This only happens once so it's bearable
        #self.get_client() # prompt for the PIN before displaying the dialog if necessary
        #self.handler.show_message("Computing master public key")
        if xtype in ['p2wpkh', 'p2wsh'] and not self.supports_native_segwit():
            raise UserFacingException(MSG_NEEDS_FW_UPDATE_SEGWIT)
        if xtype in ['p2wpkh-p2sh', 'p2wsh-p2sh'] and not self.supports_segwit():
            raise UserFacingException(MSG_NEEDS_FW_UPDATE_SEGWIT)
        bip32_path = bip32.normalize_bip32_derivation(bip32_path)
        bip32_intpath = bip32.convert_bip32_path_to_list_of_uint32(bip32_path)
        bip32_path = bip32_path[2:]  # cut off "m/"
        if len(bip32_intpath) >= 1:
            prevPath = bip32.convert_bip32_intpath_to_strpath(bip32_intpath[:-1])[2:]
            nodeData = self.dongleObject.getWalletPublicKey(prevPath)
            publicKey = compress_public_key(nodeData['publicKey'])
            fingerprint_bytes = hash_160(publicKey)[0:4]
            childnum_bytes = bip32_intpath[-1].to_bytes(length=4, byteorder="big")
        else:
            fingerprint_bytes = bytes(4)
            childnum_bytes = bytes(4)
        nodeData = self.dongleObject.getWalletPublicKey(bip32_path)
        publicKey = compress_public_key(nodeData['publicKey'])
        depth = len(bip32_intpath)
        return BIP32Node(xtype=xtype,
                         eckey=ecc.ECPubkey(bytes(publicKey)),
                         chaincode=nodeData['chainCode'],
                         depth=depth,
                         fingerprint=fingerprint_bytes,
                         child_number=childnum_bytes).to_xpub()

    def has_detached_pin_support(self, client):
        try:
            client.getVerifyPinRemainingAttempts()
            return True
        except BTChipException as e:
            if e.sw == 0x6d00:
                return False
            raise e

    def is_pin_validated(self, client):
        try:
            # Invalid SET OPERATION MODE to verify the PIN status
            client.dongle.exchange(bytearray([0xe0, 0x26, 0x00, 0x00, 0x01, 0xAB]))
        except BTChipException as e:
            if (e.sw == 0x6982):
                return False
            if (e.sw == 0x6A80):
                return True
            raise e

    def supports_multi_output(self):
        return self.multiOutputSupported

    def supports_segwit(self):
        return self.segwitSupported

    def supports_native_segwit(self):
        return self.nativeSegwitSupported

    def supports_segwit_trustedInputs(self):
        return self.segwitTrustedInputs

    def perform_hw1_preflight(self):
        try:
            firmwareInfo = self.dongleObject.getFirmwareVersion()
            firmware = firmwareInfo['version']
            self.multiOutputSupported = versiontuple(firmware) >= versiontuple(MULTI_OUTPUT_SUPPORT)
            self.nativeSegwitSupported = versiontuple(firmware) >= versiontuple(SEGWIT_SUPPORT)
            self.segwitSupported = self.nativeSegwitSupported or (firmwareInfo['specialVersion'] == 0x20 and versiontuple(firmware) >= versiontuple(SEGWIT_SUPPORT_SPECIAL))
            self.segwitTrustedInputs = versiontuple(firmware) >= versiontuple(SEGWIT_TRUSTEDINPUTS)

            if not checkFirmware(firmwareInfo):
                self.close()
                raise UserFacingException(MSG_NEEDS_FW_UPDATE_GENERIC)
            try:
                self.dongleObject.getOperationMode()
            except BTChipException as e:
                if (e.sw == 0x6985):
                    self.close()
                    self.handler.get_setup( )
                    # Acquire the new client on the next run
                else:
                    raise e
            if self.has_detached_pin_support(self.dongleObject) and not self.is_pin_validated(self.dongleObject):
                assert self.handler, "no handler for client"
                remaining_attempts = self.dongleObject.getVerifyPinRemainingAttempts()
                if remaining_attempts != 1:
                    msg = "Enter your Ledger PIN - remaining attempts : " + str(remaining_attempts)
                else:
                    msg = "Enter your Ledger PIN - WARNING : LAST ATTEMPT. If the PIN is not correct, the dongle will be wiped."
                confirmed, p, pin = self.password_dialog(msg)
                if not confirmed:
                    raise UserFacingException('Aborted by user - please unplug the dongle and plug it again before retrying')
                pin = pin.encode()
                self.dongleObject.verifyPin(pin)
        except BTChipException as e:
            if (e.sw == 0x6faa):
                raise UserFacingException("Dongle is temporarily locked - please unplug it and replug it again")
            if ((e.sw & 0xFFF0) == 0x63c0):
                raise UserFacingException("Invalid PIN - please unplug the dongle and plug it again before retrying")
            if e.sw == 0x6f00 and e.message == 'Invalid channel':
                # based on docs 0x6f00 might be a more general error, hence we also compare message to be sure
                raise UserFacingException("Invalid channel.\n"
                                          "Please make sure that 'Browser support' is disabled on your device.")
            raise e

    def checkDevice(self):
        if not self.preflightDone:
            try:
                self.perform_hw1_preflight()
            except BTChipException as e:
                if (e.sw == 0x6d00 or e.sw == 0x6700):
                    raise UserFacingException(_("Device not in Bitcoin mode")) from e
                raise e
            self.preflightDone = True

    def password_dialog(self, msg=None):
        response = self.handler.get_word(msg)
        if response is None:
            return False, None, None
        return True, response, response


class Ledger_KeyStore(Hardware_KeyStore):
    hw_type = 'ledger'
    device = 'Ledger'

    plugin: 'LedgerPlugin'

    def __init__(self, d):
        Hardware_KeyStore.__init__(self, d)
        # Errors and other user interaction is done through the wallet's
        # handler.  The handler is per-window and preserved across
        # device reconnects
        self.force_watching_only = False
        self.signing = False
        self.cfg = d.get('cfg', {'mode': 0})
        self.cfg = dict(self.cfg)  # convert to dict from StoredDict (see #6066)

    def dump(self):
        obj = Hardware_KeyStore.dump(self)
        obj['cfg'] = self.cfg
        return obj

    def get_client(self):
        return self.plugin.get_client(self).dongleObject

    def get_client_electrum(self) -> Optional[Ledger_Client]:
        return self.plugin.get_client(self)

    def give_error(self, message, clear_client = False):
        _logger.info(message)
        if not self.signing:
            self.handler.show_error(message)
        else:
            self.signing = False
        if clear_client:
            self.client = None
        raise UserFacingException(message)

    def set_and_unset_signing(func):
        """Function decorator to set and unset self.signing."""
        def wrapper(self, *args, **kwargs):
            try:
                self.signing = True
                return func(self, *args, **kwargs)
            finally:
                self.signing = False
        return wrapper

    def decrypt_message(self, pubkey, message, password):
        raise UserFacingException(_('Encryption and decryption are currently not supported for {}').format(self.device))

    @test_pin_unlocked
    @set_and_unset_signing
    def sign_message(self, sequence, message, password):
        message = message.encode('utf8')
        message_hash = hashlib.sha256(message).hexdigest().upper()
        # prompt for the PIN before displaying the dialog if necessary
        client = self.get_client()
        address_path = self.get_derivation_prefix()[2:] + "/%d/%d"%sequence
        self.handler.show_message("Signing message ...\r\nMessage hash: "+message_hash)
        try:
            info = self.get_client().signMessagePrepare(address_path, message)
            pin = ""
            if info['confirmationNeeded']:
                pin = self.handler.get_auth( info ) # does the authenticate dialog and returns pin
                if not pin:
                    raise UserWarning(_('Cancelled by user'))
                pin = str(pin).encode()
            signature = self.get_client().signMessageSign(pin)
        except BTChipException as e:
            if e.sw == 0x6a80:
                self.give_error("Unfortunately, this message cannot be signed by the Ledger wallet. Only alphanumerical messages shorter than 140 characters are supported. Please remove any extra characters (tab, carriage return) and retry.")
            elif e.sw == 0x6985:  # cancelled by user
                return b''
            elif e.sw == 0x6982:
                raise  # pin lock. decorator will catch it
            else:
                self.give_error(e, True)
        except UserWarning:
            self.handler.show_error(_('Cancelled by user'))
            return b''
        except Exception as e:
            self.give_error(e, True)
        finally:
            self.handler.finished()
        # Parse the ASN.1 signature
        rLength = signature[3]
        r = signature[4 : 4 + rLength]
        sLength = signature[4 + rLength + 1]
        s = signature[4 + rLength + 2:]
        if rLength == 33:
            r = r[1:]
        if sLength == 33:
            s = s[1:]
        # And convert it
        return bytes([27 + 4 + (signature[0] & 0x01)]) + r + s

    @test_pin_unlocked
    @set_and_unset_signing
    def sign_transaction(self, tx, password):
        if tx.is_complete():
            return
        inputs = []
        inputsPaths = []
        chipInputs = []
        redeemScripts = []
        changePath = ""
        output = None
        p2shTransaction = False
        segwitTransaction = False
        pin = ""
        client_ledger = self.get_client() # prompt for the PIN before displaying the dialog if necessary
        client_electrum = self.get_client_electrum()
        assert client_electrum

        # Fetch inputs of the transaction to sign
        for txin in tx.inputs():
            if txin.is_coinbase_input():
                self.give_error("Coinbase not supported")     # should never happen

            if txin.script_type in ['p2sh']:
                p2shTransaction = True

            if txin.script_type in ['p2wpkh-p2sh', 'p2wsh-p2sh']:
                if not client_electrum.supports_segwit():
                    self.give_error(MSG_NEEDS_FW_UPDATE_SEGWIT)
                segwitTransaction = True

            if txin.script_type in ['p2wpkh', 'p2wsh']:
                if not client_electrum.supports_native_segwit():
                    self.give_error(MSG_NEEDS_FW_UPDATE_SEGWIT)
                segwitTransaction = True

            my_pubkey, full_path = self.find_my_pubkey_in_txinout(txin)
            if not full_path:
                self.give_error("No matching pubkey for sign_transaction")  # should never happen
            full_path = convert_bip32_intpath_to_strpath(full_path)[2:]

            redeemScript = Transaction.get_preimage_script(txin)
            txin_prev_tx = txin.utxo
            if txin_prev_tx is None and not Transaction.is_segwit_input(txin):
                raise UserFacingException(_('Missing previous tx for legacy input.'))
            txin_prev_tx_raw = txin_prev_tx.serialize() if txin_prev_tx else None
            inputs.append([txin_prev_tx_raw,
                           txin.prevout.out_idx,
                           redeemScript,
                           txin.prevout.txid.hex(),
                           my_pubkey,
                           txin.nsequence,
                           txin.value_sats()])
            inputsPaths.append(full_path)

        # Sanity check
        if p2shTransaction:
            for txin in tx.inputs():
                if txin.script_type != 'p2sh':
                    self.give_error("P2SH / regular input mixed in same transaction not supported") # should never happen

        txOutput = var_int(len(tx.outputs()))
        for o in tx.outputs():
            txOutput += int_to_hex(o.value, 8)
            script = o.scriptpubkey.hex()
            txOutput += var_int(len(script)//2)
            txOutput += script
        txOutput = bfh(txOutput)

        if not client_electrum.supports_multi_output():
            if len(tx.outputs()) > 2:
                self.give_error("Transaction with more than 2 outputs not supported")
        for txout in tx.outputs():
            if not txout.address:
                if client_electrum.is_hw1():
                    self.give_error(_("Only address outputs are supported by {}").format(self.device))
                # note: max_size based on https://github.com/LedgerHQ/ledger-app-btc/commit/3a78dee9c0484821df58975803e40d58fbfc2c38#diff-c61ccd96a6d8b54d48f54a3bc4dfa7e2R26
                validate_op_return_output(txout, max_size=190)

        # Output "change" detection
        # - only one output and one change is authorized (for hw.1 and nano)
        # - at most one output can bypass confirmation (~change) (for all)
        if not p2shTransaction:
            has_change = False
            any_output_on_change_branch = is_any_tx_output_on_change_branch(tx)
            for txout in tx.outputs():
                if txout.is_mine and len(tx.outputs()) > 1 \
                        and not has_change:
                    # prioritise hiding outputs on the 'change' branch from user
                    # because no more than one change address allowed
                    if txout.is_change == any_output_on_change_branch:
                        my_pubkey, changePath = self.find_my_pubkey_in_txinout(txout)
                        assert changePath
                        changePath = convert_bip32_intpath_to_strpath(changePath)[2:]
                        has_change = True
                    else:
                        output = txout.address
                else:
                    output = txout.address

        self.handler.show_message(_("Confirm Transaction on your Ledger device..."))
        try:
            # Get trusted inputs from the original transactions
            for utxo in inputs:
                sequence = int_to_hex(utxo[5], 4)
                if segwitTransaction and not client_electrum.supports_segwit_trustedInputs():
                    tmp = bfh(utxo[3])[::-1]
                    tmp += bfh(int_to_hex(utxo[1], 4))
                    tmp += bfh(int_to_hex(utxo[6], 8))  # txin['value']
                    chipInputs.append({'value' : tmp, 'witness' : True, 'sequence' : sequence})
                    redeemScripts.append(bfh(utxo[2]))
                elif (not p2shTransaction) or client_electrum.supports_multi_output():
                    txtmp = bitcoinTransaction(bfh(utxo[0]))
                    trustedInput = client_ledger.getTrustedInput(txtmp, utxo[1])
                    trustedInput['sequence'] = sequence
                    if segwitTransaction:
                        trustedInput['witness'] = True
                    chipInputs.append(trustedInput)
                    if p2shTransaction or segwitTransaction:
                        redeemScripts.append(bfh(utxo[2]))
                    else:
                        redeemScripts.append(txtmp.outputs[utxo[1]].script)
                else:
                    tmp = bfh(utxo[3])[::-1]
                    tmp += bfh(int_to_hex(utxo[1], 4))
                    chipInputs.append({'value' : tmp, 'sequence' : sequence})
                    redeemScripts.append(bfh(utxo[2]))

            # Sign all inputs
            firstTransaction = True
            inputIndex = 0
            rawTx = tx.serialize_to_network()
            client_ledger.enableAlternate2fa(False)
            if segwitTransaction:
                client_ledger.startUntrustedTransaction(True, inputIndex,
                                                            chipInputs, redeemScripts[inputIndex], version=tx.version)
                # we don't set meaningful outputAddress, amount and fees
                # as we only care about the alternateEncoding==True branch
                outputData = client_ledger.finalizeInput(b'', 0, 0, changePath, bfh(rawTx))
                outputData['outputData'] = txOutput
                if outputData['confirmationNeeded']:
                    outputData['address'] = output
                    self.handler.finished()
                    pin = self.handler.get_auth( outputData ) # does the authenticate dialog and returns pin
                    if not pin:
                        raise UserWarning()
                    self.handler.show_message(_("Confirmed. Signing Transaction..."))
                while inputIndex < len(inputs):
                    singleInput = [ chipInputs[inputIndex] ]
                    client_ledger.startUntrustedTransaction(False, 0,
                                                            singleInput, redeemScripts[inputIndex], version=tx.version)
                    inputSignature = client_ledger.untrustedHashSign(inputsPaths[inputIndex], pin, lockTime=tx.locktime)
                    inputSignature[0] = 0x30 # force for 1.4.9+
                    my_pubkey = inputs[inputIndex][4]
                    tx.add_signature_to_txin(txin_idx=inputIndex,
                                             signing_pubkey=my_pubkey.hex(),
                                             sig=inputSignature.hex())
                    inputIndex = inputIndex + 1
            else:
                while inputIndex < len(inputs):
                    client_ledger.startUntrustedTransaction(firstTransaction, inputIndex,
                                                                chipInputs, redeemScripts[inputIndex], version=tx.version)
                    # we don't set meaningful outputAddress, amount and fees
                    # as we only care about the alternateEncoding==True branch
                    outputData = client_ledger.finalizeInput(b'', 0, 0, changePath, bfh(rawTx))
                    outputData['outputData'] = txOutput
                    if outputData['confirmationNeeded']:
                        outputData['address'] = output
                        self.handler.finished()
                        pin = self.handler.get_auth( outputData ) # does the authenticate dialog and returns pin
                        if not pin:
                            raise UserWarning()
                        self.handler.show_message(_("Confirmed. Signing Transaction..."))
                    else:
                        # Sign input with the provided PIN
                        inputSignature = client_ledger.untrustedHashSign(inputsPaths[inputIndex], pin, lockTime=tx.locktime)
                        inputSignature[0] = 0x30 # force for 1.4.9+
                        my_pubkey = inputs[inputIndex][4]
                        tx.add_signature_to_txin(txin_idx=inputIndex,
                                                 signing_pubkey=my_pubkey.hex(),
                                                 sig=inputSignature.hex())
                        inputIndex = inputIndex + 1
                    firstTransaction = False
        except UserWarning:
            self.handler.show_error(_('Cancelled by user'))
            return
        except BTChipException as e:
            if e.sw in (0x6985, 0x6d00):  # cancelled by user
                return
            elif e.sw == 0x6982:
                raise  # pin lock. decorator will catch it
            else:
                self.logger.exception('')
                self.give_error(e, True)
        except BaseException as e:
            self.logger.exception('')
            self.give_error(e, True)
        finally:
            self.handler.finished()

    @test_pin_unlocked
    @set_and_unset_signing
    def show_address(self, sequence, txin_type):
        client = self.get_client()
        address_path = self.get_derivation_prefix()[2:] + "/%d/%d"%sequence
        self.handler.show_message(_("Showing address ..."))
        segwit = is_segwit_script_type(txin_type)
        segwitNative = txin_type == 'p2wpkh'
        try:
            client.getWalletPublicKey(address_path, showOnScreen=True, segwit=segwit, segwitNative=segwitNative)
        except BTChipException as e:
            if e.sw == 0x6985:  # cancelled by user
                pass
            elif e.sw == 0x6982:
                raise  # pin lock. decorator will catch it
            elif e.sw == 0x6b00:  # hw.1 raises this
                self.handler.show_error('{}\n{}\n{}'.format(
                    _('Error showing address') + ':',
                    e,
                    _('Your device might not have support for this functionality.')))
            else:
                self.logger.exception('')
                self.handler.show_error(e)
        except BaseException as e:
            self.logger.exception('')
            self.handler.show_error(e)
        finally:
            self.handler.finished()

class LedgerPlugin(HW_PluginBase):
    keystore_class = Ledger_KeyStore
    minimum_library = (0, 1, 30)
    client = None
    DEVICE_IDS = [
                   (0x2581, 0x1807), # HW.1 legacy btchip
                   (0x2581, 0x2b7c), # HW.1 transitional production
                   (0x2581, 0x3b7c), # HW.1 ledger production
                   (0x2581, 0x4b7c), # HW.1 ledger test
                   (0x2c97, 0x0000), # Blue
                   (0x2c97, 0x0001), # Nano-S
                   (0x2c97, 0x0004), # Nano-X
                   (0x2c97, 0x0005), # RFU
                   (0x2c97, 0x0006), # RFU
                   (0x2c97, 0x0007), # RFU
                   (0x2c97, 0x0008), # RFU
                   (0x2c97, 0x0009), # RFU
                   (0x2c97, 0x000a)  # RFU
                 ]
    SUPPORTED_XTYPES = ('standard', 'p2wpkh-p2sh', 'p2wpkh', 'p2wsh-p2sh', 'p2wsh')

    def __init__(self, parent, config, name):
        self.segwit = config.get("segwit")
        HW_PluginBase.__init__(self, parent, config, name)
        self.libraries_available = self.check_libraries_available()
        if not self.libraries_available:
            return
        self.device_manager().register_devices(self.DEVICE_IDS, plugin=self)

    def get_library_version(self):
        try:
            import btchip
            version = btchip.__version__
        except ImportError:
            raise
        except:
            version = "unknown"
        if BTCHIP:
            return version
        else:
            raise LibraryFoundButUnusable(library_version=version)

    def get_btchip_device(self, device):
        ledger = False
        if device.product_key[0] == 0x2581 and device.product_key[1] == 0x3b7c:
            ledger = True
        if device.product_key[0] == 0x2581 and device.product_key[1] == 0x4b7c:
            ledger = True
        if device.product_key[0] == 0x2c97:
            if device.interface_number == 0 or device.usage_page == 0xffa0:
                ledger = True
            else:
                return None  # non-compatible interface of a Nano S or Blue
        with self.device_manager().hid_lock:
            dev = hid.device()
            dev.open_path(device.path)
            dev.set_nonblocking(True)
        return HIDDongleHIDAPI(dev, ledger, BTCHIP_DEBUG)

    def create_client(self, device, handler):
        if handler:
            self.handler = handler

        client = self.get_btchip_device(device)
        if client is not None:
            client = Ledger_Client(client, product_key=device.product_key, plugin=self)
        return client

    def setup_device(self, device_info, wizard, purpose):
        device_id = device_info.device.id_
        client = self.scan_and_create_client_for_device(device_id=device_id, wizard=wizard)
        wizard.run_task_without_blocking_gui(
            task=lambda: client.get_xpub("m/44'/0'", 'standard'))  # TODO replace by direct derivation once Nano S > 1.1
        return client

    def get_xpub(self, device_id, derivation, xtype, wizard):
        if xtype not in self.SUPPORTED_XTYPES:
            raise ScriptTypeNotSupported(_('This type of script is not supported with {}.').format(self.device))
        client = self.scan_and_create_client_for_device(device_id=device_id, wizard=wizard)
        client.checkDevice()
        xpub = client.get_xpub(derivation, xtype)
        return xpub

    def get_client(self, keystore, force_pair=True, *,
                   devices=None, allow_user_interaction=True):
        # All client interaction should not be in the main GUI thread
        client = super().get_client(keystore, force_pair,
                                    devices=devices,
                                    allow_user_interaction=allow_user_interaction)
        # returns the client for a given keystore. can use xpub
        #if client:
        #    client.used()
        if client is not None:
            client.checkDevice()
        return client

    def show_address(self, wallet, address, keystore=None):
        if keystore is None:
            keystore = wallet.get_keystore()
        if not self.show_address_helper(wallet, address, keystore):
            return
        if type(wallet) is not Standard_Wallet:
            keystore.handler.show_error(_('This function is only available for standard wallets when using {}.').format(self.device))
            return
        sequence = wallet.get_address_index(address)
        txin_type = wallet.get_txin_type(address)
        keystore.show_address(sequence, txin_type)