michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
michael@0:  * You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: "use strict";
michael@0: 
michael@0: this.EXPORTED_SYMBOLS = [
michael@0:   "BulkKeyBundle",
michael@0:   "SyncKeyBundle"
michael@0: ];
michael@0: 
michael@0: const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
michael@0: 
michael@0: Cu.import("resource://services-sync/constants.js");
michael@0: Cu.import("resource://gre/modules/Log.jsm");
michael@0: Cu.import("resource://services-sync/util.js");
michael@0: 
michael@0: /**
michael@0:  * Represents a pair of keys.
michael@0:  *
michael@0:  * Each key stored in a key bundle is 256 bits. One key is used for symmetric
michael@0:  * encryption. The other is used for HMAC.
michael@0:  *
michael@0:  * A KeyBundle by itself is just an anonymous pair of keys. Other types
michael@0:  * deriving from this one add semantics, such as associated collections or
michael@0:  * generating a key bundle via HKDF from another key.
michael@0:  */
michael@0: function KeyBundle() {
michael@0:   this._encrypt = null;
michael@0:   this._encryptB64 = null;
michael@0:   this._hmac = null;
michael@0:   this._hmacB64 = null;
michael@0:   this._hmacObj = null;
michael@0:   this._sha256HMACHasher = null;
michael@0: }
michael@0: KeyBundle.prototype = {
michael@0:   _encrypt: null,
michael@0:   _encryptB64: null,
michael@0:   _hmac: null,
michael@0:   _hmacB64: null,
michael@0:   _hmacObj: null,
michael@0:   _sha256HMACHasher: null,
michael@0: 
michael@0:   equals: function equals(bundle) {
michael@0:     return bundle &&
michael@0:            (bundle.hmacKey == this.hmacKey) &&
michael@0:            (bundle.encryptionKey == this.encryptionKey);
michael@0:   },
michael@0: 
michael@0:   /*
michael@0:    * Accessors for the two keys.
michael@0:    */
michael@0:   get encryptionKey() {
michael@0:     return this._encrypt;
michael@0:   },
michael@0: 
michael@0:   set encryptionKey(value) {
michael@0:     if (!value || typeof value != "string") {
michael@0:       throw new Error("Encryption key can only be set to string values.");
michael@0:     }
michael@0: 
michael@0:     if (value.length < 16) {
michael@0:       throw new Error("Encryption key must be at least 128 bits long.");
michael@0:     }
michael@0: 
michael@0:     this._encrypt = value;
michael@0:     this._encryptB64 = btoa(value);
michael@0:   },
michael@0: 
michael@0:   get encryptionKeyB64() {
michael@0:     return this._encryptB64;
michael@0:   },
michael@0: 
michael@0:   get hmacKey() {
michael@0:     return this._hmac;
michael@0:   },
michael@0: 
michael@0:   set hmacKey(value) {
michael@0:     if (!value || typeof value != "string") {
michael@0:       throw new Error("HMAC key can only be set to string values.");
michael@0:     }
michael@0: 
michael@0:     if (value.length < 16) {
michael@0:       throw new Error("HMAC key must be at least 128 bits long.");
michael@0:     }
michael@0: 
michael@0:     this._hmac = value;
michael@0:     this._hmacB64 = btoa(value);
michael@0:     this._hmacObj = value ? Utils.makeHMACKey(value) : null;
michael@0:     this._sha256HMACHasher = value ? Utils.makeHMACHasher(
michael@0:       Ci.nsICryptoHMAC.SHA256, this._hmacObj) : null;
michael@0:   },
michael@0: 
michael@0:   get hmacKeyB64() {
michael@0:     return this._hmacB64;
michael@0:   },
michael@0: 
michael@0:   get hmacKeyObject() {
michael@0:     return this._hmacObj;
michael@0:   },
michael@0: 
michael@0:   get sha256HMACHasher() {
michael@0:     return this._sha256HMACHasher;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Populate this key pair with 2 new, randomly generated keys.
michael@0:    */
michael@0:   generateRandom: function generateRandom() {
michael@0:     let generatedHMAC = Svc.Crypto.generateRandomKey();
michael@0:     let generatedEncr = Svc.Crypto.generateRandomKey();
michael@0:     this.keyPairB64 = [generatedEncr, generatedHMAC];
michael@0:   },
michael@0: 
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Represents a KeyBundle associated with a collection.
michael@0:  *
michael@0:  * This is just a KeyBundle with a collection attached.
michael@0:  */
michael@0: this.BulkKeyBundle = function BulkKeyBundle(collection) {
michael@0:   let log = Log.repository.getLogger("Sync.BulkKeyBundle");
michael@0:   log.info("BulkKeyBundle being created for " + collection);
michael@0:   KeyBundle.call(this);
michael@0: 
michael@0:   this._collection = collection;
michael@0: }
michael@0: 
michael@0: BulkKeyBundle.prototype = {
michael@0:   __proto__: KeyBundle.prototype,
michael@0: 
michael@0:   get collection() {
michael@0:     return this._collection;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Obtain the key pair in this key bundle.
michael@0:    *
michael@0:    * The returned keys are represented as raw byte strings.
michael@0:    */
michael@0:   get keyPair() {
michael@0:     return [this.encryptionKey, this.hmacKey];
michael@0:   },
michael@0: 
michael@0:   set keyPair(value) {
michael@0:     if (!Array.isArray(value) || value.length != 2) {
michael@0:       throw new Error("BulkKeyBundle.keyPair value must be array of 2 keys.");
michael@0:     }
michael@0: 
michael@0:     this.encryptionKey = value[0];
michael@0:     this.hmacKey       = value[1];
michael@0:   },
michael@0: 
michael@0:   get keyPairB64() {
michael@0:     return [this.encryptionKeyB64, this.hmacKeyB64];
michael@0:   },
michael@0: 
michael@0:   set keyPairB64(value) {
michael@0:     if (!Array.isArray(value) || value.length != 2) {
michael@0:       throw new Error("BulkKeyBundle.keyPairB64 value must be an array of 2 " +
michael@0:                       "keys.");
michael@0:     }
michael@0: 
michael@0:     this.encryptionKey  = Utils.safeAtoB(value[0]);
michael@0:     this.hmacKey        = Utils.safeAtoB(value[1]);
michael@0:   },
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Represents a key pair derived from a Sync Key via HKDF.
michael@0:  *
michael@0:  * Instances of this type should be considered immutable. You create an
michael@0:  * instance by specifying the username and 26 character "friendly" Base32
michael@0:  * encoded Sync Key. The Sync Key is derived at instance creation time.
michael@0:  *
michael@0:  * If the username or Sync Key is invalid, an Error will be thrown.
michael@0:  */
michael@0: this.SyncKeyBundle = function SyncKeyBundle(username, syncKey) {
michael@0:   let log = Log.repository.getLogger("Sync.SyncKeyBundle");
michael@0:   log.info("SyncKeyBundle being created.");
michael@0:   KeyBundle.call(this);
michael@0: 
michael@0:   this.generateFromKey(username, syncKey);
michael@0: }
michael@0: SyncKeyBundle.prototype = {
michael@0:   __proto__: KeyBundle.prototype,
michael@0: 
michael@0:   /*
michael@0:    * If we've got a string, hash it into keys and store them.
michael@0:    */
michael@0:   generateFromKey: function generateFromKey(username, syncKey) {
michael@0:     if (!username || (typeof username != "string")) {
michael@0:       throw new Error("Sync Key cannot be generated from non-string username.");
michael@0:     }
michael@0: 
michael@0:     if (!syncKey || (typeof syncKey != "string")) {
michael@0:       throw new Error("Sync Key cannot be generated from non-string key.");
michael@0:     }
michael@0: 
michael@0:     if (!Utils.isPassphrase(syncKey)) {
michael@0:       throw new Error("Provided key is not a passphrase, cannot derive Sync " +
michael@0:                       "Key Bundle.");
michael@0:     }
michael@0: 
michael@0:     // Expand the base32 Sync Key to an AES 256 and 256 bit HMAC key.
michael@0:     let prk = Utils.decodeKeyBase32(syncKey);
michael@0:     let info = HMAC_INPUT + username;
michael@0:     let okm = Utils.hkdfExpand(prk, info, 32 * 2);
michael@0:     this.encryptionKey = okm.slice(0, 32);
michael@0:     this.hmacKey = okm.slice(32, 64);
michael@0:   },
michael@0: };
michael@0: