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import { assert } from '@0xproject/assert';
import { addressUtils } from '@0xproject/utils';
import EthereumTx = require('ethereumjs-tx');
import ethUtil = require('ethereumjs-util');
import HDNode = require('hdkey');
import * as _ from 'lodash';
import { Lock } from 'semaphore-async-await';
import {
Callback,
LedgerEthereumClient,
LedgerEthereumClientFactoryAsync,
LedgerSubproviderConfigs,
LedgerSubproviderErrors,
PartialTxParams,
ResponseWithTxParams,
WalletSubproviderErrors,
} from '../types';
import { BaseWalletSubprovider } from './base_wallet_subprovider';
const DEFAULT_DERIVATION_PATH = `44'/60'/0'`;
const DEFAULT_NUM_ADDRESSES_TO_FETCH = 10;
const ASK_FOR_ON_DEVICE_CONFIRMATION = false;
const SHOULD_GET_CHAIN_CODE = true;
/**
* Subprovider for interfacing with a user's [Ledger Nano S](https://www.ledgerwallet.com/products/ledger-nano-s).
* This subprovider intercepts all account related RPC requests (e.g message/transaction signing, etc...) and
* re-routes them to a Ledger device plugged into the users computer.
*/
export class LedgerSubprovider extends BaseWalletSubprovider {
private _nonceLock = new Lock();
private _connectionLock = new Lock();
private _networkId: number;
private _derivationPath: string;
private _derivationPathIndex: number;
private _ledgerEthereumClientFactoryAsync: LedgerEthereumClientFactoryAsync;
private _ledgerClientIfExists?: LedgerEthereumClient;
private _shouldAlwaysAskForConfirmation: boolean;
/**
* Instantiates a LedgerSubprovider. Defaults to derivationPath set to `44'/60'/0'`.
* TestRPC/Ganache defaults to `m/44'/60'/0'/0`, so set this in the configs if desired.
* @param config Several available configurations
* @return LedgerSubprovider instance
*/
constructor(config: LedgerSubproviderConfigs) {
super();
this._networkId = config.networkId;
this._ledgerEthereumClientFactoryAsync = config.ledgerEthereumClientFactoryAsync;
this._derivationPath = config.derivationPath || DEFAULT_DERIVATION_PATH;
this._shouldAlwaysAskForConfirmation =
!_.isUndefined(config.accountFetchingConfigs) &&
!_.isUndefined(config.accountFetchingConfigs.shouldAskForOnDeviceConfirmation)
? config.accountFetchingConfigs.shouldAskForOnDeviceConfirmation
: ASK_FOR_ON_DEVICE_CONFIRMATION;
this._derivationPathIndex = 0;
}
/**
* Retrieve the set derivation path
* @returns derivation path
*/
public getPath(): string {
return this._derivationPath;
}
/**
* Set a desired derivation path when computing the available user addresses
* @param derivationPath The desired derivation path (e.g `44'/60'/0'`)
*/
public setPath(derivationPath: string) {
this._derivationPath = derivationPath;
}
/**
* Set the final derivation path index. If a user wishes to sign a message with the
* 6th address in a derivation path, before calling `signPersonalMessageAsync`, you must
* call this method with pathIndex `6`.
* @param pathIndex Desired derivation path index
*/
public setPathIndex(pathIndex: number) {
this._derivationPathIndex = pathIndex;
}
/**
* Retrieve a users Ledger accounts. The accounts are derived from the derivationPath,
* master public key and chainCode. Because of this, you can request as many accounts
* as you wish and it only requires a single request to the Ledger device. This method
* is automatically called when issuing a `eth_accounts` JSON RPC request via your providerEngine
* instance.
* @param numberOfAccounts Number of accounts to retrieve (default: 10)
* @return An array of accounts
*/
public async getAccountsAsync(numberOfAccounts: number = DEFAULT_NUM_ADDRESSES_TO_FETCH): Promise<string[]> {
this._ledgerClientIfExists = await this._createLedgerClientAsync();
let ledgerResponse;
try {
ledgerResponse = await this._ledgerClientIfExists.getAddress(
this._derivationPath,
this._shouldAlwaysAskForConfirmation,
SHOULD_GET_CHAIN_CODE,
);
} finally {
await this._destroyLedgerClientAsync();
}
const hdKey = new HDNode();
hdKey.publicKey = new Buffer(ledgerResponse.publicKey, 'hex');
hdKey.chainCode = new Buffer(ledgerResponse.chainCode, 'hex');
const accounts: string[] = [];
for (let i = 0; i < numberOfAccounts; i++) {
const derivedHDNode = hdKey.derive(`m/${i + this._derivationPathIndex}`);
const derivedPublicKey = derivedHDNode.publicKey;
const shouldSanitizePublicKey = true;
const ethereumAddressUnprefixed = ethUtil
.publicToAddress(derivedPublicKey, shouldSanitizePublicKey)
.toString('hex');
const ethereumAddressPrefixed = ethUtil.addHexPrefix(ethereumAddressUnprefixed);
accounts.push(ethereumAddressPrefixed.toLowerCase());
}
return accounts;
}
/**
* Sign a transaction with the Ledger. If you've added the LedgerSubprovider to your
* app's provider, you can simply send an `eth_sendTransaction` JSON RPC request, and
* this method will be called auto-magically. If you are not using this via a ProviderEngine
* instance, you can call it directly.
* @param txParams Parameters of the transaction to sign
* @return Signed transaction hex string
*/
public async signTransactionAsync(txParams: PartialTxParams): Promise<string> {
LedgerSubprovider._validateTxParams(txParams);
this._ledgerClientIfExists = await this._createLedgerClientAsync();
const tx = new EthereumTx(txParams);
// Set the EIP155 bits
tx.raw[6] = Buffer.from([this._networkId]); // v
tx.raw[7] = Buffer.from([]); // r
tx.raw[8] = Buffer.from([]); // s
const txHex = tx.serialize().toString('hex');
try {
const derivationPath = this._getDerivationPath();
const result = await this._ledgerClientIfExists.signTransaction(derivationPath, txHex);
// Store signature in transaction
tx.r = Buffer.from(result.r, 'hex');
tx.s = Buffer.from(result.s, 'hex');
tx.v = Buffer.from(result.v, 'hex');
// EIP155: v should be chain_id * 2 + {35, 36}
const signedChainId = Math.floor((tx.v[0] - 35) / 2);
if (signedChainId !== this._networkId) {
await this._destroyLedgerClientAsync();
const err = new Error(LedgerSubproviderErrors.TooOldLedgerFirmware);
throw err;
}
const signedTxHex = `0x${tx.serialize().toString('hex')}`;
await this._destroyLedgerClientAsync();
return signedTxHex;
} catch (err) {
await this._destroyLedgerClientAsync();
throw err;
}
}
/**
* Sign a personal Ethereum signed message. The signing address will be the one
* retrieved given a derivationPath and pathIndex set on the subprovider.
* The Ledger adds the Ethereum signed message prefix on-device. If you've added
* the LedgerSubprovider to your app's provider, you can simply send an `eth_sign`
* or `personal_sign` JSON RPC request, and this method will be called auto-magically.
* If you are not using this via a ProviderEngine instance, you can call it directly.
* @param data Message to sign
* @return Signature hex string (order: rsv)
*/
public async signPersonalMessageAsync(data: string): Promise<string> {
if (_.isUndefined(data)) {
throw new Error(WalletSubproviderErrors.DataMissingForSignPersonalMessage);
}
assert.isHexString('data', data);
this._ledgerClientIfExists = await this._createLedgerClientAsync();
try {
const derivationPath = this._getDerivationPath();
const result = await this._ledgerClientIfExists.signPersonalMessage(
derivationPath,
ethUtil.stripHexPrefix(data),
);
const v = result.v - 27;
let vHex = v.toString(16);
if (vHex.length < 2) {
vHex = `0${v}`;
}
const signature = `0x${result.r}${result.s}${vHex}`;
await this._destroyLedgerClientAsync();
return signature;
} catch (err) {
await this._destroyLedgerClientAsync();
throw err;
}
}
private _getDerivationPath() {
const derivationPath = `${this.getPath()}/${this._derivationPathIndex}`;
return derivationPath;
}
private async _createLedgerClientAsync(): Promise<LedgerEthereumClient> {
await this._connectionLock.acquire();
if (!_.isUndefined(this._ledgerClientIfExists)) {
this._connectionLock.release();
throw new Error(LedgerSubproviderErrors.MultipleOpenConnectionsDisallowed);
}
const ledgerEthereumClient = await this._ledgerEthereumClientFactoryAsync();
this._connectionLock.release();
return ledgerEthereumClient;
}
private async _destroyLedgerClientAsync() {
await this._connectionLock.acquire();
if (_.isUndefined(this._ledgerClientIfExists)) {
this._connectionLock.release();
return;
}
await this._ledgerClientIfExists.transport.close();
this._ledgerClientIfExists = undefined;
this._connectionLock.release();
}
}
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