FIDO U2F component extension

chrome/browser/resources/cryptotoken/llhidgnubby.js

Index: chrome/browser/resources/cryptotoken/llhidgnubby.js
diff --git a/chrome/browser/resources/cryptotoken/llhidgnubby.js b/chrome/browser/resources/cryptotoken/llhidgnubby.js
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+// Copyright (c) 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/**
+ * @fileoverview Implements a low-level gnubby driver based on chrome.hid.
+ */
+'use strict';
+
+/**
+ * Low level gnubby 'driver'. One per physical USB device.
+ * @param {Gnubbies} gnubbies The gnubbies instances this device is enumerated
+ *     in.
+ * @param {!chrome.hid.ConnectionHandle} dev The device.
+ * @param {number} id The device's id.
+ * @constructor
+ * @implements {llGnubby}
+ */
+function llHidGnubby(gnubbies, dev, id) {
+  /** @private {Gnubbies} */
+  this.gnubbies_ = gnubbies;
+  this.dev = dev;
+  this.id = id;
+  this.txqueue = [];
+  this.clients = [];
+  this.lockCID = 0;     // channel ID of client holding a lock, if != 0.
+  this.lockMillis = 0;  // current lock period.
+  this.lockTID = null;  // timer id of lock timeout.
+  this.closing = false;  // device to be closed by receive loop.
+  this.updating = false;  // device firmware is in final stage of updating.
+}
+
+/**
+ * Namespace for the llHidGnubby implementation.
+ * @const
+ */
+llHidGnubby.NAMESPACE = 'hid';
+
+/** Destroys this low-level device instance. */
+llHidGnubby.prototype.destroy = function() {
+  if (!this.dev) return;  // Already dead.
+
+  this.closing = true;
+
+  console.log(UTIL_fmt('llHidGnubby.destroy()'));
+
+  // Synthesize a close error frame to alert all clients,
+  // some of which might be in read state.
+  //
+  // Use magic CID 0 to address all.
+  this.publishFrame_(new Uint8Array([
+        0, 0, 0, 0,  // broadcast CID
+        llGnubby.CMD_ERROR,
+        0, 1,  // length
+        llGnubby.GONE]).buffer);
+
+  // Set all clients to closed status and remove them.
+  while (this.clients.length != 0) {
+    var client = this.clients.shift();
+    if (client) client.closed = true;
+  }
+
+  if (this.lockTID) {
+    window.clearTimeout(this.lockTID);
+    this.lockTID = null;
+  }
+
+  var dev = this.dev;
+  this.dev = null;
+
+  var self = this;
+
+  function onClosed() {
+    console.log(UTIL_fmt('Device ' + dev.handle + ' closed'));
+    self.gnubbies_.removeOpenDevice(
+        {namespace: llHidGnubby.NAMESPACE, device: self.id});
+  }
+
+  chrome.hid.disconnect(dev.connectionId, onClosed);
+};
+
+/**
+ * Push frame to all clients.
+ * @param {ArrayBuffer} f
+ * @private
+ */
+llHidGnubby.prototype.publishFrame_ = function(f) {
+  var old = this.clients;
+
+  var remaining = [];
+  var changes = false;
+  for (var i = 0; i < old.length; ++i) {
+    var client = old[i];
+    if (client.receivedFrame(f)) {
+      // Client still alive; keep on list.
+      remaining.push(client);
+    } else {
+      changes = true;
+      console.log(UTIL_fmt(
+          '[' + client.cid.toString(16) + '] left?'));
+    }
+  }
+  if (changes) this.clients = remaining;
+};
+
+/**
+ * @return {boolean} whether this device is open and ready to use.
+ * @private
+ */
+llHidGnubby.prototype.readyToUse_ = function() {
+  if (this.closing) return false;
+  if (!this.dev) return false;
+
+  return true;
+};
+
+/**
+ * Register a client for this gnubby.
+ * @param {*} who The client.
+ */
+llHidGnubby.prototype.registerClient = function(who) {
+  for (var i = 0; i < this.clients.length; ++i) {
+    if (this.clients[i] === who) return;  // Already registered.
+  }
+  this.clients.push(who);
+  if (this.clients.length == 1) {
+    // First client? Kick off read loop.
+    this.readLoop_();
+  }
+};
+
+/**
+ * De-register a client.
+ * @param {*} who The client.
+ * @return {number} The number of remaining listeners for this device, or -1
+ * Returns number of remaining listeners for this device.
+ *     if this had no clients to start with.
+ */
+llHidGnubby.prototype.deregisterClient = function(who) {
+  var current = this.clients;
+  if (current.length == 0) return -1;
+  this.clients = [];
+  for (var i = 0; i < current.length; ++i) {
+    var client = current[i];
+    if (client !== who) this.clients.push(client);
+  }
+  return this.clients.length;
+};
+
+/**
+ * @param {*} who The client.
+ * @return {boolean} Whether this device has who as a client.
+ */
+llHidGnubby.prototype.hasClient = function(who) {
+  if (this.clients.length == 0) return false;
+  for (var i = 0; i < this.clients.length; ++i) {
+    if (who === this.clients[i])
+      return true;
+  }
+  return false;
+};
+
+/**
+ * Reads all incoming frames and notifies clients of their receipt.
+ * @private
+ */
+llHidGnubby.prototype.readLoop_ = function() {
+  //console.log(UTIL_fmt('entering readLoop'));
+  if (!this.dev) return;
+
+  if (this.closing) {
+    this.destroy();
+    return;
+  }
+
+  // No interested listeners, yet we hit readLoop().
+  // Must be clean-up. We do this here to make sure no transfer is pending.
+  if (!this.clients.length) {
+    this.closing = true;
+    this.destroy();
+    return;
+  }
+
+  // firmwareUpdate() sets this.updating when writing the last block before
+  // the signature. We process that reply with the already pending
+  // read transfer but we do not want to start another read transfer for the
+  // signature block, since that request will have no reply.
+  // Instead we will see the device drop and re-appear on the bus.
+  // Current libusb on some platforms gets unhappy when transfer are pending
+  // when that happens.
+  // TODO(mschilder): revisit once Chrome stabilizes its behavior.
+  if (this.updating) {
+    console.log(UTIL_fmt('device updating. Ending readLoop()'));
+    return;
+  }
+
+  var self = this;
+  chrome.hid.receive(
+    this.dev.connectionId,
+    64,
+    function(x) {
+      if (chrome.runtime.lastError || !x) {
+        console.log(UTIL_fmt('got lastError'));
+        console.log(chrome.runtime.lastError);
+        window.setTimeout(function() { self.destroy(); }, 0);
+        return;
+      }
+      var u8 = new Uint8Array(x);
+      //console.log(UTIL_fmt('<' + UTIL_BytesToHex(u8)));
+
+      self.publishFrame_(x);
+
+      // Read more.
+      window.setTimeout(function() { self.readLoop_(); }, 0);
+    }
+  );
+};
+
+/**
+ * Check whether channel is locked for this request or not.
+ * @param {number} cid
+ * @param {number} cmd
+ * @return {boolean} true if not locked for this request.
+ * @private
+ */
+llHidGnubby.prototype.checkLock_ = function(cid, cmd) {
+  if (this.lockCID) {
+    // We have an active lock.
+    if (this.lockCID != cid) {
+      // Some other channel has active lock.
+
+      if (cmd != llGnubby.CMD_SYNC) {
+        // Anything but SYNC gets an immediate busy.
+        var busy = new Uint8Array(
+            [(cid >> 24) & 255,
+             (cid >> 16) & 255,
+             (cid >> 8) & 255,
+             cid & 255,
+             llGnubby.CMD_ERROR,
+             0, 1,  // length
+             llGnubby.BUSY]);
+        // Log the synthetic busy too.
+        console.log(UTIL_fmt('<' + UTIL_BytesToHex(busy)));
+        this.publishFrame_(busy.buffer);
+        return false;
+      }
+
+      // SYNC gets to go to the device to flush OS tx/rx queues.
+      // The usb firmware always responds to SYNC, regardless of lock status.
+    }
+  }
+  return true;
+};
+
+/**
+ * Update or grab lock.
+ * @param {number} cid
+ * @param {number} cmd
+ * @param {number} arg
+ * @private
+ */
+llHidGnubby.prototype.updateLock_ = function(cid, cmd, arg) {
+  if (this.lockCID == 0 || this.lockCID == cid) {
+    // It is this caller's or nobody's lock.
+    if (this.lockTID) {
+      window.clearTimeout(this.lockTID);
+      this.lockTID = null;
+    }
+
+    if (cmd == llGnubby.CMD_LOCK) {
+      var nseconds = arg;
+      if (nseconds != 0) {
+        this.lockCID = cid;
+        // Set tracking time to be .1 seconds longer than usb device does.
+        this.lockMillis = nseconds * 1000 + 100;
+      } else {
+        // Releasing lock voluntarily.
+        this.lockCID = 0;
+      }
+    }
+
+    // (re)set the lock timeout if we still hold it.
+    if (this.lockCID) {
+      var self = this;
+      this.lockTID = window.setTimeout(
+          function() {
+            console.warn(UTIL_fmt(
+                'lock for CID ' + cid.toString(16) + ' expired!'));
+            self.lockTID = null;
+            self.lockCID = 0;
+          },
+          this.lockMillis);
+    }
+  }
+};
+
+/**
+ * Queue command to be sent.
+ * If queue was empty, initiate the write.
+ * @param {number} cid The client's channel ID.
+ * @param {number} cmd The command to send.
+ * @param {ArrayBuffer} data
+ */
+llHidGnubby.prototype.queueCommand = function(cid, cmd, data) {
+  if (!this.dev) return;
+  if (!this.checkLock_(cid, cmd)) return;
+
+  var u8 = new Uint8Array(data);
+  var f = new Uint8Array(64);
+
+  llHidGnubby.setCid_(f, cid);
+  f[4] = cmd;
+  f[5] = (u8.length >> 8);
+  f[6] = (u8.length & 255);
+
+  var lockArg = (u8.length > 0) ? u8[0] : 0;
+
+  // Fragment over our 64 byte frames.
+  var n = 7;
+  var seq = 0;
+  for (var i = 0; i < u8.length; ++i) {
+    f[n++] = u8[i];
+    if (n == f.length) {
+      this.queueFrame_(f.buffer, cid, cmd, lockArg);
+
+      f = new Uint8Array(64);
+      llHidGnubby.setCid_(f, cid);
+      cmd = f[4] = seq++;
+      n = 5;
+    }
+  }
+  if (n != 5) {
+    this.queueFrame_(f.buffer, cid, cmd, lockArg);
+  }
+};
+
+/**
+ * Sets the channel id in the frame.
+ * @param {Uint8Array} frame
+ * @param {number} cid The client's channel ID.
+ * @private
+ */
+llHidGnubby.setCid_ = function(frame, cid) {
+  frame[0] = cid >>> 24;
+  frame[1] = cid >>> 16;
+  frame[2] = cid >>> 8;
+  frame[3] = cid;
+};
+
+/**
+ * Updates the lock, and queues the frame for sending. Also begins sending if
+ * no other writes are outstanding.
+ * @param {ArrayBuffer} frame
+ * @param {number} cid The client's channel ID.
+ * @param {number} cmd The command to send.
+ * @param {number} arg
+ * @private
+ */
+llHidGnubby.prototype.queueFrame_ = function(frame, cid, cmd, arg) {
+  this.updateLock_(cid, cmd, arg);
+  var wasEmpty = (this.txqueue.length == 0);
+  this.txqueue.push(frame);
+  if (wasEmpty) this.writePump_();
+};
+
+/**
+ * Stuff queued frames from txqueue[] to device, one by one.
+ * @private
+ */
+llHidGnubby.prototype.writePump_ = function() {
+  if (!this.dev) return;  // Ignore.
+
+  if (this.txqueue.length == 0) return;  // Done with current queue.
+
+  var frame = this.txqueue[0];
+
+  var self = this;
+  function transferComplete(x) {
+    if (chrome.runtime.lastError) {
+      console.log(UTIL_fmt('got lastError'));
+      console.log(chrome.runtime.lastError);
+      window.setTimeout(function() { self.destroy(); }, 0);
+      return;
+    }
+    self.txqueue.shift();  // drop sent frame from queue.
+    if (self.txqueue.length != 0) {
+      window.setTimeout(function() { self.writePump_(); }, 0);
+    }
+  };
+
+  var u8 = new Uint8Array(frame);
+  //console.log(UTIL_fmt('>' + UTIL_BytesToHex(u8)));
+
+  var u8f = new Uint8Array(64);
+  for (var i = 0; i < u8.length; ++i) {
+    u8f[i] = u8[i];
+  }
+
+  chrome.hid.send(
+      this.dev.connectionId,
+      0, // report Id
+      u8f.buffer,
+      transferComplete
+  );
+};
+/**
+ * @param {function(Array)} cb
+ */
+llHidGnubby.enumerate = function(cb) {
+  chrome.hid.getDevices({'vendorId': 4176, 'productId': 512}, cb);
+};
+
+/**
+ * @param {Gnubbies} gnubbies The gnubbies instances this device is enumerated
+ *     in.
+ * @param {number} which The index of the device to open.
+ * @param {!chrome.hid.HidDeviceInfo} dev The device to open.
+ * @param {function(number, llGnubby=)} cb Called back with the
+ *     result of opening the device.
+ */
+llHidGnubby.open = function(gnubbies, which, dev, cb) {
+  chrome.hid.connect(dev.deviceId, function(handle) {
+    if (chrome.runtime.lastError) {
+      console.log(chrome.runtime.lastError);
+    }
+    if (!handle) {
+      console.warn(UTIL_fmt('failed to connect device. permissions issue?'));
+      cb(-llGnubby.NODEVICE);
+      return;
+    }
+    var nonNullHandle = /** @type {!chrome.hid.HidConnection} */ (handle);
+    var gnubby = new llHidGnubby(gnubbies, nonNullHandle, which);
+    cb(-llGnubby.OK, gnubby);
+  });
+};
+
+/**
+ * @param {*} dev
+ * @return {llGnubbyDeviceId} A device identifier for the device.
+ */
+llHidGnubby.deviceToDeviceId = function(dev) {
+  var hidDev = /** @type {!chrome.hid.HidDeviceInfo} */ (dev);
+  var deviceId = { namespace: llHidGnubby.NAMESPACE, device: hidDev.deviceId };
+  return deviceId;
+};
+
+/**
+ * Registers this implementation with gnubbies.
+ * @param {Gnubbies} gnubbies
+ */
+llHidGnubby.register = function(gnubbies) {
+  var HID_GNUBBY_IMPL = {
+    enumerate: llHidGnubby.enumerate,
+    deviceToDeviceId: llHidGnubby.deviceToDeviceId,
+    open: llHidGnubby.open
+  };
+  gnubbies.registerNamespace(llHidGnubby.NAMESPACE, HID_GNUBBY_IMPL);
+};