Merge pull request #24 from mozilla/tls13-psk-mode; r=vladikoff,marti…

…nthomson

Add preliminary TLS1.3 PSK-mode implementation.

.circleci/config.yml

@@ -18,9 +18,12 @@ jobs:
           shell: /bin/bash --login
           command: |
             sudo npm install -g npm@6
-            npm install
+            npm ci
             DISPLAY=:99 FIREFOX_BIN=./firefox/firefox-bin npm test
 
+      - store_artifacts:
+          path: ./coverage/
+
       - run: npm run lint
 workflows:
   version: 2

.gitignore

@@ -1,3 +1,6 @@
+# Build with coverage info enabled.
+dist/FxAccountsPairingChannel.babel.umd.coverage.js 
+
 # Logs
 logs
 *.log

README.md

@@ -8,19 +8,15 @@ It will be used by the Firefox Accounts pairing flow, with one side
 of the channel being web content from https://accounts.firefox.com and
 the other side of the channel being a signed-in Firefox instance.
 
-The connection will *eventually* be secured using a pre-shared key
-and TLS1.3, but that code is still in progress. To parallelize
-client development we've published an initial version with a
-correctly-shapred API but no meaningful security.
 
 API
 ===
 
-The main abstraction is the `InsecurePairingChannel` class.
+The main abstraction is the `PairingChannel` class.
 One side of the connection can create a new channel like this:
 
 ```
-const channel = await InsecurePairingChannel.create(CHANNEL_SERVER_URL);
+const channel = await PairingChannel.create(CHANNEL_SERVER_URL);
 console.log(channel.channelId, channel.channelKey);
 ```
 
@@ -29,7 +25,7 @@ the intended client, perhaps by scanning a QR code.  It can then
 connect to the channel like this:
 
 ```
-const channel = await InsecurePairingChannel.connect(CHANNEL_SERVER_URL, channelId, channelKey);
+const channel = await PairingChannel.connect(CHANNEL_SERVER_URL, channelId, channelKey);
 ```
 
 Both ends of the channel can then send and receive messages using a websocket-like
@@ -46,4 +42,14 @@ channel.addEventListener("message", event => {
 
 You can try out a more complete demo of this API by loading
 `./demo/test_client.html` and `./demo/test_server.html` in
-parallel webpages and watching them pass messages back and forth.
+parallel webpages and watching them pass messages back and forth.
+
+
+Crypto
+======
+
+Under the hood, the `PairingChannel` implements the "externally-provisioned
+pre-shared key" mode of [TLS1.3](https://tools.ietf.org/html/rfc8446).
+Each side of the channel can thus be assured that its peer is in posession
+of the `channelKey`, and that their traffic is protected from anyone who
+does not possess this key.

demo/test_client.html

@@ -22,15 +22,15 @@ <h2>fxa-pairing-tls demo client</h2>
   <script src="../dist/FxAccountsPairingChannel.babel.umd.js"></script>
   <script>
     $(() => {
-      const {InsecurePairingChannel, hexToBytes} = FxAccountsPairingChannel;
+      const {PairingChannel, base64urlToBytes} = FxAccountsPairingChannel;
       const CHANNEL_SERVER = 'wss://dev.channelserver.nonprod.cloudops.mozgcp.net';
       $("#code-value").val("")
       $("#chat-history").val("")
       $("#code-value").on("keypress", async evt => {
         if (evt.keyCode !== 13) { return }
         const [channelId, pskHex] = $("#code-value").val().split("#");
-        const psk = hexToBytes(pskHex);
-        const channel = await InsecurePairingChannel.connect(CHANNEL_SERVER, channelId, psk);
+        const psk = base64urlToBytes(pskHex);
+        const channel = await PairingChannel.connect(CHANNEL_SERVER, channelId, psk);
         channel.addEventListener("message", event => {
           const {msg} = event.detail.data;
           $("#chat-history").val($("#chat-history").val() + "\nthem>> " + msg)

demo/test_server.html

@@ -21,12 +21,11 @@ <h2>fxa-pairing-tls demo server</h2>
   <script src="../dist/FxAccountsPairingChannel.babel.umd.js"></script>
   <script>
     $(async () => {
-      // TODO: do we want to export InsecurePairingChannel directly?
-      const {InsecurePairingChannel, bytesToHex} = FxAccountsPairingChannel;
+      const {PairingChannel, bytesToBase64url} = FxAccountsPairingChannel;
       const CHANNEL_SERVER = 'wss://dev.channelserver.nonprod.cloudops.mozgcp.net';
       $("#chat-history").val("");
-      const channel = await InsecurePairingChannel.create(CHANNEL_SERVER);
-      $("#code-value").text(`${channel.channelId}#${bytesToHex(channel.channelKey)}`);
+      const channel = await PairingChannel.create(CHANNEL_SERVER);
+      $("#code-value").text(`${channel.channelId}#${bytesToBase64url(channel.channelKey)}`);
       channel.addEventListener("message", event => {
         const {msg} = event.detail.data;
         $("#chat-history").val($("#chat-history").val() + "\nthem>> " + msg);