Do minimal processing of gnubby data. Add request timeouts and send error

remoting/webapp/gnubby_auth_handler.js

Index: remoting/webapp/gnubby_auth_handler.js
diff --git a/remoting/webapp/gnubby_auth_handler.js b/remoting/webapp/gnubby_auth_handler.js
index 848ab1e018b02563b99226426066ddc9aaad8b4d..1291b8669815f1c1cb4c8e15b7dd2dd02341d83c 100644
--- a/remoting/webapp/gnubby_auth_handler.js
+++ b/remoting/webapp/gnubby_auth_handler.js
@@ -30,9 +30,13 @@ remoting.GnubbyAuthHandler.prototype.onMessage = function(data) {
   var message = getJsonObjectFromString(data);
   var messageType = getStringAttr(message, 'type');
   if (messageType == 'data') {
+    var base64Data = getStringAttr(message, 'base64Data');
+    var requestData = window.atob(/** @type {string} */ base64Data);

[Sergey Ulanov, 2014/03/21 02:09:37]

move @type above base64Data declaration

[Sergey Ulanov, 2014/03/21 02:09:37]

The host encodes the data in base64 and here the client reencodes it to an array
of numbers. Is it just to reduce size of the message on the wire, or are the
other reasons the host can't send the message as array of numbers?

[psj, 2014/03/21 21:30:45]

Done.

[psj, 2014/03/21 21:30:45]

The compiler can't figure out the type when it is there, but that really doesn't
matter anymore...

+    var connectionId = getNumberAttr(message, 'connectionId');
     this.sendMessageToGnubbyd_(
-        getJsonObjectFromString(getStringAttr(message, 'jsonMessage')),
-        this.callback_.bind(this, getNumberAttr(message, 'connectionId')));
+        {'type': 'auth-agent@openssh.com',
+          'data': stringToBytes_(requestData)},
+        this.callback_.bind(this, connectionId));
   } else {
     console.error('Invalid gnubby-auth message: ' + messageType);
   }
@@ -41,15 +45,25 @@ remoting.GnubbyAuthHandler.prototype.onMessage = function(data) {
 /**
  * Callback invoked with data to be returned to the host.
  * @param {number} connectionId The connection id.
- * @param {Object} data The JSON object to send to the host.
+ * @param {Object} response The JSON response with the data to send to the host.
  * @private
  */
 remoting.GnubbyAuthHandler.prototype.callback_ =
-    function(connectionId, data) {
-  var json_data = JSON.stringify(data);
+    function(connectionId, response) {
+  var base64Data;
+  try {
+    var responseData = getArrayAttr(response, 'data');
+    base64Data = window.btoa(bytesToString_(responseData));
+  } catch (err) {
+    console.error('gnubby callback failed: ', /** @type {*} */ (err));

[Sergey Ulanov, 2014/03/21 02:09:37]

Not sure why it may fail here? If we fail to reencode message doesn't it mean
that gnubbyd send a bogus message?

[psj, 2014/03/21 21:30:45]

It will fail if response doesn't contain data, or if data isn't an array. This
would happen if there is an old version of gnubbyd is installed

+    this.clientSession_.sendGnubbyAuthMessage({'type': 'error',
+      'connectionId': connectionId});
+    return;
+  }
+
   this.clientSession_.sendGnubbyAuthMessage({'type': 'data',
     'connectionId': connectionId,
-    'jsonMessage': json_data});
+    'base64Data': base64Data});
 };
 
 /**
@@ -86,4 +100,26 @@ function onGnubbydDevReply_(jsonObject, callback, reply) {
   } else {
     chrome.runtime.sendMessage(kGnubbydStableExtensionId, jsonObject, callback);
   }
-};
+}
+
+/**
+ * Convert a string to an array of bytes.
+ * @param {string} s The string to convert.
+ * @return {Array.<number>} The converted bytes.
+ */
+function stringToBytes_(s) {
+  var bytes = Array(s.length);
+  for (var i = 0; i < s.length; ++i) {
+    bytes[i] = s.charCodeAt(i);
+  }
+  return bytes;
+}
+
+/**
+ * Convert an array of bytes to a string.
+ * @param {Array.<number>} b The bytes to convert.
+ * @return {string} The converted string.
+ */
+function bytesToString_(b) {
+  return String.fromCharCode.apply(null, b);
+}