Fix race and remove unused features in cryptotoken extension

chrome/browser/resources/cryptotoken/gnubby-u2f.js

Index: chrome/browser/resources/cryptotoken/gnubby-u2f.js
diff --git a/chrome/browser/resources/cryptotoken/gnubby-u2f.js b/chrome/browser/resources/cryptotoken/gnubby-u2f.js
index 653b957d01175acdafa007f8471eea9742a6df47..39a73d6a8a75e4d108149811b61fa7483ff59d47 100644
--- a/chrome/browser/resources/cryptotoken/gnubby-u2f.js
+++ b/chrome/browser/resources/cryptotoken/gnubby-u2f.js
@@ -7,7 +7,6 @@
  */
 'use strict';
 
-// Commands and flags of the Gnubby applet at
 /** Enroll */
 usbGnubby.U2F_ENROLL = 0x01;
 /** Request signature */
@@ -28,6 +27,12 @@ usbGnubby.P1_TUP_TESTONLY = 0x04;
 /** Attest with device key */
 usbGnubby.P1_INDIVIDUAL_KEY = 0x80;
 
+// Version values
+/** V1 of the applet. */
+usbGnubby.U2F_V1 = 'U2F_V1';
+/** V2 of the applet. */
+usbGnubby.U2F_V2 = 'U2F_V2';
+
 /** Perform enrollment
  * @param {ArrayBuffer|Uint8Array} challenge Enrollment challenge
  * @param {ArrayBuffer|Uint8Array} appIdHash Hashed application id
@@ -63,33 +68,51 @@ usbGnubby.prototype.enroll = function(challenge, appIdHash, cb) {
  */
 usbGnubby.prototype.sign = function(challengeHash, appIdHash, keyHandle, cb,
                                     opt_nowink) {
-  var apdu = new Uint8Array(
-      [0x00,
-       usbGnubby.U2F_SIGN,
-       usbGnubby.P1_TUP_REQUIRED | usbGnubby.P1_TUP_CONSUME,
-       0x00, 0x00, 0x00,
-      challengeHash.length + appIdHash.length + keyHandle.length]);
-  if (opt_nowink) {
-    // A signature request that does not want winking.
-    // These are used during enroll to figure out whether a gnubby was already
-    // enrolled.
-    // Tell applet to not actually produce a signature, even
-    // if already touched.
-    apdu[2] |= usbGnubby.P1_TUP_TESTONLY;
-  }
-  var u8 = new Uint8Array(apdu.length + challengeHash.length +
-      appIdHash.length + keyHandle.length + 2);
-  for (var i = 0; i < apdu.length; ++i) u8[i] = apdu[i];
-  for (var i = 0; i < challengeHash.length; ++i) u8[i + apdu.length] =
-    challengeHash[i];
-  for (var i = 0; i < appIdHash.length; ++i) {
-    u8[i + apdu.length + challengeHash.length] = appIdHash[i];
-  }
-  for (var i = 0; i < keyHandle.length; ++i) {
-    u8[i + apdu.length + challengeHash.length + appIdHash.length] =
-        keyHandle[i];
-  }
-  this.apduReply_(u8.buffer, cb, opt_nowink);
+  var self = this;
+  // The sign command's format is ever-so-slightly different between V1 and V2,
+  // so get this gnubby's version prior to sending it.
+  this.version(function(rc, opt_data) {
+    if (rc) {
+      cb(rc);
+      return;
+    }
+    var version = UTIL_BytesToString(new Uint8Array(opt_data || []));
+    var apduDataLen =
+      challengeHash.length + appIdHash.length + keyHandle.length;
+    if (version != usbGnubby.U2F_V1) {
+      // The V2 sign command includes a length byte for the key handle.
+      apduDataLen++;
+    }
+    var apdu = new Uint8Array(
+        [0x00,
+         usbGnubby.U2F_SIGN,
+         usbGnubby.P1_TUP_REQUIRED | usbGnubby.P1_TUP_CONSUME,
+         0x00, 0x00, 0x00,
+         apduDataLen]);
+    if (opt_nowink) {
+      // A signature request that does not want winking.
+      // These are used during enroll to figure out whether a gnubby was already
+      // enrolled.
+      // Tell applet to not actually produce a signature, even
+      // if already touched.
+      apdu[2] |= usbGnubby.P1_TUP_TESTONLY;
+    }
+    var u8 = new Uint8Array(apdu.length + apduDataLen + 2);
+    for (var i = 0; i < apdu.length; ++i) u8[i] = apdu[i];
+    for (var i = 0; i < challengeHash.length; ++i) u8[i + apdu.length] =
+      challengeHash[i];
+    for (var i = 0; i < appIdHash.length; ++i) {
+      u8[i + apdu.length + challengeHash.length] = appIdHash[i];
+    }
+    var keyHandleOffset = apdu.length + challengeHash.length + appIdHash.length;
+    if (version != usbGnubby.U2F_V1) {
+      u8[keyHandleOffset++] = keyHandle.length;
+    }
+    for (var i = 0; i < keyHandle.length; ++i) {
+      u8[i + keyHandleOffset] = keyHandle[i];
+    }
+    self.apduReply_(u8.buffer, cb, opt_nowink);
+  });
 };
 
 /** Request version information
@@ -97,14 +120,23 @@ usbGnubby.prototype.sign = function(challengeHash, appIdHash, keyHandle, cb,
  */
 usbGnubby.prototype.version = function(cb) {
   if (!cb) cb = usbGnubby.defaultCallback;
+  if (this.version_) {
+    cb(-llGnubby.OK, this.version_);
+    return;
+  }
+  var self = this;
   var apdu = new Uint8Array([0x00, usbGnubby.U2F_VERSION, 0x00, 0x00, 0x00,
       0x00, 0x00, 0x00, 0x00]);
   this.apduReply_(apdu.buffer, function(rc, data) {
     if (rc == 0x6d00) {
       // Command not implemented. Pretend this is v1.
-      var v1 = new Uint8Array(UTIL_StringToBytes('U2F_V1'));
+      var v1 = new Uint8Array(UTIL_StringToBytes(usbGnubby.U2F_V1));
+      self.version_ = v1.buffer;
       cb(-llGnubby.OK, v1.buffer);
     } else {
+      if (!rc) {
+        self.version_ = data;
+      }
       cb(rc, data);
     }
   });