1 files changed, 173 insertions, 0 deletions
diff --git a/services/sync/modules/keys.js b/services/sync/modules/keys.js
new file mode 100644
index 0000000000..5bdc5f8399
--- /dev/null
+++ b/services/sync/modules/keys.js
@@ -0,0 +1,173 @@
+/* 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";
+
+var EXPORTED_SYMBOLS = ["BulkKeyBundle"];
+
+const { CommonUtils } = ChromeUtils.import(
+  "resource://services-common/utils.js"
+);
+const { Log } = ChromeUtils.importESModule(
+  "resource://gre/modules/Log.sys.mjs"
+);
+const { Weave } = ChromeUtils.import("resource://services-sync/main.js");
+const { Utils } = ChromeUtils.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;
+}
+KeyBundle.prototype = {
+  _encrypt: null,
+  _encryptB64: null,
+  _hmac: null,
+  _hmacB64: 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);
+  },
+
+  get hmacKeyB64() {
+    return this._hmacB64;
+  },
+
+  /**
+   * Populate this key pair with 2 new, randomly generated keys.
+   */
+  async generateRandom() {
+    // Compute both at that same time
+    let [generatedHMAC, generatedEncr] = await Promise.all([
+      Weave.Crypto.generateRandomKey(),
+      Weave.Crypto.generateRandomKey(),
+    ]);
+    this.keyPairB64 = [generatedEncr, generatedHMAC];
+  },
+};
+
+/**
+ * Represents a KeyBundle associated with a collection.
+ *
+ * This is just a KeyBundle with a collection attached.
+ */
+function BulkKeyBundle(collection) {
+  let log = Log.repository.getLogger("Sync.BulkKeyBundle");
+  log.info("BulkKeyBundle being created for " + collection);
+  KeyBundle.call(this);
+
+  this._collection = collection;
+}
+
+BulkKeyBundle.fromHexKey = function(hexKey) {
+  let key = CommonUtils.hexToBytes(hexKey);
+  let bundle = new BulkKeyBundle();
+  // [encryptionKey, hmacKey]
+  bundle.keyPair = [key.slice(0, 32), key.slice(32, 64)];
+  return bundle;
+};
+
+BulkKeyBundle.fromJWK = function(jwk) {
+  if (!jwk || !jwk.k || jwk.kty !== "oct") {
+    throw new Error("Invalid JWK provided to BulkKeyBundle.fromJWK");
+  }
+  return BulkKeyBundle.fromHexKey(CommonUtils.base64urlToHex(jwk.k));
+};
+
+BulkKeyBundle.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 = CommonUtils.safeAtoB(value[0]);
+    this.hmacKey = CommonUtils.safeAtoB(value[1]);
+  },
+};
+
+Object.setPrototypeOf(BulkKeyBundle.prototype, KeyBundle.prototype);