multi: Add ledger backend functions.

app/actions/LedgerActions.js

@@ -0,0 +1,205 @@
+import TransportWebUSB from "@ledgerhq/hw-transport-webusb";
+import { createTransaction } from "@ledgerhq/hw-app-btc/lib/createTransaction";
+import Btc from "@ledgerhq/hw-app-btc";
+import * as ledgerHelpers from "../helpers/ledger";
+import { wallet } from "wallet-preload-shim";
+import { publishTransactionAttempt } from "./ControlActions";
+import { hexToBytes } from "helpers";
+import {
+  SIGNTX_ATTEMPT,
+  SIGNTX_FAILED,
+  SIGNTX_SUCCESS
+} from "./ControlActions";
+
+const coin = "decred";
+
+import * as selectors from "selectors";
+import * as cfgConstants from "constants/config";
+
+export const LDG_LEDGER_ENABLED = "LDG_LEDGER_ENABLED";
+export const LDG_WALLET_CLOSED = "LDG_WALLET_CLOSED";
+
+// This is an error's message when an app is open but we are trying to get
+// device info.
+// const DEVICE_ON_DASHBOARD_EXPECTED = "DeviceOnDashboardExpected";
+
+// enableLedger only sets a value in the config. Ledger connections are made
+// per action then dropped.
+export const enableLedger = () => (dispatch, getState) => {
+  const walletName = selectors.getWalletName(getState());
+
+  if (walletName) {
+    const config = wallet.getWalletCfg(
+      selectors.isTestNet(getState()),
+      walletName
+    );
+    config.set(cfgConstants.LEDGER, true);
+  }
+
+  dispatch({ type: LDG_LEDGER_ENABLED });
+
+  connect()(dispatch, getState);
+};
+
+export const LDG_CONNECT_ATTEMPT = "LDG_CONNECT_ATTEMPT";
+export const LDG_CONNECT_FAILED = "LDG_CONNECT_FAILED";
+export const LDG_CONNECT_SUCCESS = "LDG_CONNECT_SUCCESS";
+
+// connect only checks that a connection does not error, so a device exists and
+// is plugged in.
+export const connect = () => async (dispatch /*, getState*/) => {
+  dispatch({ type: LDG_CONNECT_ATTEMPT });
+  try {
+    await doWithTransport(async () => {});
+  } catch (error) {
+    dispatch({ type: LDG_CONNECT_FAILED });
+    throw error;
+  }
+  dispatch({ type: LDG_CONNECT_SUCCESS });
+};
+
+export const LDG_LEDGER_DISABLED = "LDG_LEDGER_DISABLED";
+
+// disableLedger disables ledger integration for the current wallet. Note
+// that it does **not** disable in the config, so the wallet will restart as a
+// ledger wallet next time it's opened.
+export const disableLedger = () => (dispatch) => {
+  dispatch({ type: LDG_LEDGER_DISABLED });
+};
+
+export const LDG_NOCONNECTEDDEVICE = "LDG_NOCONNECTEDDEVICE";
+
+export const alertNoConnectedDevice = () => (dispatch) => {
+  dispatch({ type: LDG_NOCONNECTEDDEVICE });
+};
+
+// checkLedgerIsDcrwallet verifies whether the wallet currently running on
+// dcrwallet (presumably a watch only wallet created from a ledger provided
+// xpub) is the same wallet as the one of the currently connected ledger. This
+// function throws an error if they are not the same.
+// This is useful for making sure, prior to performing some wallet related
+// function such as transaction signing, that ledger will correctly perform the
+// operation.
+// Note that this might trigger pin/passphrase modals, depending on the current
+// ledger configuration.
+// The way the check is performed is by generating the first address from the
+// ledger wallet and then validating this address agains dcrwallet, ensuring
+// this is an owned address at the appropriate branch/index.
+// This check is only valid for a single session (ie, a single execution of
+// `deviceRun`) as the physical device might change between sessions.
+const checkLedgerIsDcrwallet = () => async (dispatch, getState) => {
+  const {
+    grpc: { walletService }
+  } = getState();
+
+  const path = ledgerHelpers.addressPath(0, 0);
+  const payload = await getAddress(path);
+  const addr = payload.bitcoinAddress;
+
+  const addrValidResp = await wallet.validateAddress(walletService, addr);
+  if (!addrValidResp.isValid)
+    throw "Ledger provided an invalid address " + addr;
+
+  if (!addrValidResp.isMine)
+    throw "Ledger and dcrwallet not running from the same extended public key";
+
+  if (addrValidResp.index !== 0) throw "Wallet replied with wrong index.";
+};
+
+export const signTransactionAttemptLedger =
+  (rawUnsigTx) => async (dispatch, getState) => {
+    dispatch({ type: SIGNTX_ATTEMPT });
+    const {
+      grpc: { walletService }
+    } = getState();
+    const chainParams = selectors.chainParams(getState());
+
+    try {
+      const arg = await ledgerHelpers.signArg(
+        rawUnsigTx,
+        chainParams,
+        walletService,
+        dispatch
+      );
+
+      await dispatch(checkLedgerIsDcrwallet());
+      const signedRaw = await createTx(arg);
+      if (signedRaw.message) {
+        throw signedRaw.message;
+      }
+
+      dispatch({ type: SIGNTX_SUCCESS });
+      dispatch(publishTransactionAttempt(hexToBytes(signedRaw)));
+    } catch (error) {
+      dispatch({ error, type: SIGNTX_FAILED });
+    }
+  };
+
+export const LDG_GETWALLETCREATIONMASTERPUBKEY_ATTEMPT =
+  "LDG_GETWALLETCREATIONMASTERPUBKEY_ATTEMPT";
+export const LDG_GETWALLETCREATIONMASTERPUBKEY_FAILED =
+  "LDG_GETWALLETCREATIONMASTERPUBKEY_FAILED";
+export const LDG_GETWALLETCREATIONMASTERPUBKEY_SUCCESS =
+  "LDG_GETWALLETCREATIONMASTERPUBKEY_SUCCESS";
+
+export const getWalletCreationMasterPubKey =
+  () => async (dispatch /*, getState*/) => {
+    dispatch({ type: LDG_GETWALLETCREATIONMASTERPUBKEY_ATTEMPT });
+    // TODO: Enable on mainnet.
+    const isTestnet = true;
+    try {
+      const payload = await getPubKey(isTestnet);
+      const hdpk = ledgerHelpers.fixPubKeyChecksum(payload);
+      dispatch({ type: LDG_GETWALLETCREATIONMASTERPUBKEY_SUCCESS });
+      return hdpk;
+    } catch (error) {
+      dispatch({ error, type: LDG_GETWALLETCREATIONMASTERPUBKEY_FAILED });
+      throw error;
+    }
+  };
+
+function doWithTransport(fn) {
+  return TransportWebUSB.create()
+    .then((transport) => {
+      return fn(transport).then((r) =>
+        transport
+          .close()
+          .catch((/*e*/) => {}) // throw?
+          .then(() => r)
+      );
+    })
+    .catch((e) => {
+      throw e;
+    });
+}
+
+function getAddress(path) {
+  const fn = async (transport) => {
+    const btc = new Btc({ transport, currency: coin });
+    return await btc.getWalletPublicKey(path, {
+      verify: false
+    });
+  };
+  return doWithTransport(fn);
+}
+
+function getPubKey(isTestnet) {
+  const fn = async (transport) => {
+    const btc = new Btc({ transport, currency: coin });
+    let hdPublicKeyID = 0x02fda926; // dpub
+    if (isTestnet) {
+      hdPublicKeyID = 0x043587d1; // tpub
+    }
+    return await btc.getWalletXpub({
+      path: "44'/42'/0'",
+      xpubVersion: hdPublicKeyID
+    });
+  };
+  return doWithTransport(fn);
+}
+
+function createTx(arg) {
+  return doWithTransport((transport) => {
+    return createTransaction(transport, arg);
+  });
+}

app/helpers/ledger.js

@@ -0,0 +1,164 @@
+import { wallet } from "wallet-preload-shim";
+import { strHashToRaw } from "helpers";
+import { default as blake } from "blake-hash";
+import * as bs58 from "bs58";
+import toBuffer from "typedarray-to-buffer";
+import { getTxFromInputs } from "../actions/TransactionActions";
+
+export function addressPath(branch, index) {
+  const prefix = "44'/42'/0'/";
+  const i = (index || 0).toString();
+  const b = (branch || 0).toString();
+  return prefix + b + "/" + i;
+}
+
+// fixPubKeyChecksum replaces the sha256 checksum, or last four bytes, of a
+// pubkey with a blake256 checksum.
+export function fixPubKeyChecksum(pubKey) {
+  const buff = bs58.decode(pubKey).slice(0, -4);
+  const firstPass = blake("blake256").update(Buffer.from(buff)).digest();
+  const secondPass = blake("blake256").update(firstPass).digest();
+  const fullSerialize = Buffer.concat([
+    Buffer.from(buff),
+    secondPass.slice(0, 4)
+  ]);
+  return bs58.encode(fullSerialize);
+}
+
+function writeUint16LE(n) {
+  const buff = new Buffer(2);
+  buff.writeUInt16LE(n, 0);
+  return buff;
+}
+
+function writeUint32LE(n) {
+  const buff = new Buffer(4);
+  buff.writeUInt32LE(n, 0);
+  return buff;
+}
+
+function writeUint64LE(n) {
+  const buff = new Buffer(8);
+  const lower = 0xffffffff & n;
+  // bitshift right (>>>) does not seem to throw away the lower half, so
+  // dividing and throwing away the remainder.
+  const upper = Math.floor(n / 0xffffffff);
+  buff.writeUInt32LE(lower, 0);
+  buff.writeUInt32LE(upper, 4);
+  return buff;
+}
+
+function inputToTx(tx) {
+  const inputs = [];
+  for (const inp of tx.inputs) {
+    const sequence = writeUint32LE(inp.sequence);
+    const tree = new Uint8Array(1);
+    tree[0] = inp.outputTree;
+    const prevout = new Uint8Array(36);
+    prevout.set(strHashToRaw(inp.prevTxId), 0);
+    prevout.set(writeUint32LE(inp.outputIndex), 32);
+    const input = {
+      prevout: toBuffer(prevout),
+      script: toBuffer(new Uint8Array(25)),
+      sequence: sequence,
+      tree: toBuffer(tree)
+    };
+    inputs.push(input);
+  }
+  const outputs = [];
+  for (const out of tx.outputs) {
+    const output = {
+      amount: writeUint64LE(out.value),
+      script: out.script
+    };
+    outputs.push(output);
+  }
+  return {
+    version: writeUint32LE(tx.version), // Pretty sure this is a uint16 but ledger does not want that.
+    inputs: inputs,
+    outputs: outputs,
+    locktime: writeUint32LE(tx.lockTime),
+    nExpiryHeight: writeUint32LE(tx.expiry)
+  };
+}
+
+function createPrefix(tx) {
+  const numOuts = tx.outputs.length;
+  // TODO: Allow more outputs if possible.
+  if (numOuts > 2) {
+    throw "more than two outputs is not expected";
+  }
+  let buffLen = 1;
+  for (const out of tx.outputs) {
+    buffLen += 11 + out.script.length;
+  }
+  const buff = new Uint8Array(buffLen); // 1 varInt + ( 8 value + 2 tx version + 1 varInt + (23/25?) variable script length) * number of outputs
+  let i = 0;
+  buff[i] = numOuts;
+  i += 1;
+  for (const out of tx.outputs) {
+    buff.set(writeUint64LE(out.value), i);
+    i += 8;
+    buff.set(writeUint16LE(out.version), i);
+    i += 2;
+    // TODO: Clean this up for production? Should use smarter logic to get varInts?
+    buff[i] = out.script.length; // varInt for 23/25 bytes
+    i += 1;
+    buff.set(out.script, i);
+    i += out.script.length;
+  }
+  return toBuffer(buff);
+}
+
+export async function signArg(txHex, chainParams, walletService, dispatch) {
+  const tx = await wallet.decodeTransactionLocal(txHex, chainParams);
+  const inputTxs = await dispatch(getTxFromInputs(tx));
+  const inputs = [];
+  const paths = [];
+  for (const inp of tx.inputs) {
+    let verboseInp;
+    for (const it of inputTxs) {
+      if (it.hash === inp.prevTxId) {
+        verboseInp = it;
+        break;
+      }
+    }
+    if (!verboseInp) {
+      throw "cound not find input";
+    }
+    const prevOut = inputToTx(verboseInp);
+    const idx = inp.outputIndex;
+    inputs.push([prevOut, idx]);
+    const addr = verboseInp.outputs[idx].decodedScript.address;
+    const val = await wallet.validateAddress(walletService, addr);
+    const acct = val.accountNumber.toString();
+    const branch = val.isInternal ? "1" : "0";
+    const index = val.index.toString();
+    paths.push("44'/42'/" + acct + "'/" + branch + "/" + index);
+  }
+  let changePath = null;
+  for (const out of tx.outputs) {
+    const addr = out.decodedScript.address;
+    const val = await wallet.validateAddress(walletService, addr);
+    if (!val.isInternal) {
+      continue;
+    } // assume the internal address is change
+    const acct = val.accountNumber.toString();
+    const index = val.index.toString();
+    changePath = "44'/42'/" + acct + "'/1/" + index;
+    break;
+  }
+
+  return {
+    inputs: inputs,
+    associatedKeysets: paths,
+    changePath: changePath,
+    outputScriptHex: createPrefix(tx),
+    lockTime: tx.lockTime,
+    sigHashType: 1, // SIGHASH_ALL
+    segwit: false,
+    expiryHeight: writeUint32LE(tx.expiry),
+    useTrustedInputForSegwit: false,
+    additionals: ["decred"]
+  };
+}

app/main.development.js

@@ -873,6 +873,18 @@ app.on("ready", async () => {
     height: 1000,
     icon: __dirname + "/dcrdex.png"
   });
+
+  mainWindow.webContents.session.setDevicePermissionHandler((details) => {
+    // Allow Ledger devices which share a unique vendor ID.
+    if (
+      details.deviceType === "usb" &&
+      details.device &&
+      details.device.vendorId === 0x2c97
+    ) {
+      return true;
+    }
+    return false;
+  });
 });
 
 app.on("before-quit", async (event) => {

package.json

@@ -273,6 +273,8 @@
     "@formatjs/intl-utils": "^1.6.0",
     "@grpc/grpc-js": "1.7.3",
     "@hot-loader/react-dom": "16.14.0",
+    "@ledgerhq/hw-app-btc": "^10.0.5",
+    "@ledgerhq/hw-transport-webusb": "^6.27.16",
     "@peculiar/webcrypto": "1.4.3",
     "@xstate/react": "^0.8.1",
     "blake-hash": "^2.0.0",