The Tor Browser / file revision

 /* This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this file,

  * You can obtain one at http://mozilla.org/MPL/2.0/. */

 /**

  * This module implements client-side key stretching for use in Firefox

  * Accounts account creation and login.

  *

  * See https://github.com/mozilla/fxa-auth-server/wiki/onepw-protocol

  */

 "use strict";

 this.EXPORTED_SYMBOLS = ["Credentials"];

 const {utils: Cu, interfaces: Ci} = Components;

 Cu.import("resource://gre/modules/Log.jsm");

 Cu.import("resource://gre/modules/Services.jsm");

 Cu.import("resource://gre/modules/Promise.jsm");

 Cu.import("resource://services-crypto/utils.js");

 Cu.import("resource://services-common/utils.js");

 const PROTOCOL_VERSION = "identity.mozilla.com/picl/v1/";

 const PBKDF2_ROUNDS = 1000;

 const STRETCHED_PW_LENGTH_BYTES = 32;

 const HKDF_SALT = CommonUtils.hexToBytes("00");

 const HKDF_LENGTH = 32;

 const HMAC_ALGORITHM = Ci.nsICryptoHMAC.SHA256;

 const HMAC_LENGTH = 32;

 // loglevel preference should be one of: "FATAL", "ERROR", "WARN", "INFO",

 // "CONFIG", "DEBUG", "TRACE" or "ALL". We will be logging error messages by

 // default.

 const PREF_LOG_LEVEL = "identity.fxaccounts.loglevel";

 try {

   this.LOG_LEVEL =

     Services.prefs.getPrefType(PREF_LOG_LEVEL) == Ci.nsIPrefBranch.PREF_STRING

     && Services.prefs.getCharPref(PREF_LOG_LEVEL);

 } catch (e) {

   this.LOG_LEVEL = Log.Level.Error;

 }

 let log = Log.repository.getLogger("Identity.FxAccounts");

 log.level = LOG_LEVEL;

 log.addAppender(new Log.ConsoleAppender(new Log.BasicFormatter()));

 this.Credentials = Object.freeze({

   /**

    * Make constants accessible to tests

    */

   constants: {

     PROTOCOL_VERSION: PROTOCOL_VERSION,

     PBKDF2_ROUNDS: PBKDF2_ROUNDS,

     STRETCHED_PW_LENGTH_BYTES: STRETCHED_PW_LENGTH_BYTES,

     HKDF_SALT: HKDF_SALT,

     HKDF_LENGTH: HKDF_LENGTH,

     HMAC_ALGORITHM: HMAC_ALGORITHM,

     HMAC_LENGTH: HMAC_LENGTH,

   },

   /**

    * KW function from https://github.com/mozilla/fxa-auth-server/wiki/onepw-protocol

    *

    * keyWord derivation for use as a salt.

    *

    *

    *   @param {String} context  String for use in generating salt

    *

    *   @return {bitArray} the salt

    *

    * Note that PROTOCOL_VERSION does not refer in any way to the version of the

    * Firefox Accounts API.

    */

   keyWord: function(context) {

     return CommonUtils.stringToBytes(PROTOCOL_VERSION + context);

   },

   /**

    * KWE function from https://github.com/mozilla/fxa-auth-server/wiki/onepw-protocol

    *

    * keyWord extended with a name and an email.

    *

    *   @param {String} name The name of the salt

    *   @param {String} email The email of the user.

    *

    *   @return {bitArray} the salt combination with the namespace

    *

    * Note that PROTOCOL_VERSION does not refer in any way to the version of the

    * Firefox Accounts API.

    */

   keyWordExtended: function(name, email) {

     return CommonUtils.stringToBytes(PROTOCOL_VERSION + name + ':' + email);

   },

   setup: function(emailInput, passwordInput, options={}) {

     let deferred = Promise.defer();

     log.debug("setup credentials for " + emailInput);

     let hkdfSalt = options.hkdfSalt || HKDF_SALT;

     let hkdfLength = options.hkdfLength || HKDF_LENGTH;

     let hmacLength = options.hmacLength || HMAC_LENGTH;

     let hmacAlgorithm = options.hmacAlgorithm || HMAC_ALGORITHM;

     let stretchedPWLength = options.stretchedPassLength || STRETCHED_PW_LENGTH_BYTES;

     let pbkdf2Rounds = options.pbkdf2Rounds || PBKDF2_ROUNDS;

     let result = {

       emailUTF8: emailInput,

       passwordUTF8: passwordInput,

     };

     let password = CommonUtils.encodeUTF8(passwordInput);

     let salt = this.keyWordExtended("quickStretch", emailInput);

     let runnable = () => {

       let start = Date.now();

       let quickStretchedPW = CryptoUtils.pbkdf2Generate(

           password, salt, pbkdf2Rounds, stretchedPWLength, hmacAlgorithm, hmacLength);

       result.quickStretchedPW = quickStretchedPW;

       result.authPW =

         CryptoUtils.hkdf(quickStretchedPW, hkdfSalt, this.keyWord("authPW"), hkdfLength);

       result.unwrapBKey =

         CryptoUtils.hkdf(quickStretchedPW, hkdfSalt, this.keyWord("unwrapBkey"), hkdfLength);

       log.debug("Credentials set up after " + (Date.now() - start) + " ms");

       deferred.resolve(result);

     }

     Services.tm.currentThread.dispatch(runnable,

         Ci.nsIThread.DISPATCH_NORMAL);

     log.debug("Dispatched thread for credentials setup crypto work");

     return deferred.promise;

   }

 });