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