1 files changed, 136 insertions, 0 deletions
diff --git a/services/fxaccounts/Credentials.jsm b/services/fxaccounts/Credentials.jsm
new file mode 100644
index 000000000..56e8b3db7
--- /dev/null
+++ b/services/fxaccounts/Credentials.jsm
@@ -0,0 +1,136 @@
+/* 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;
+}
+
+var 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 = {};
+
+    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;
+  }
+});
+