From c52d15cd5a4589238cb08132b4e737b0a6a4e7d9 Mon Sep 17 00:00:00 2001
From: Luke Childs <lukechilds123@gmail.com>
Date: Mon, 30 Apr 2018 16:33:45 +0700
Subject: [PATCH] Improve encryption implementation

Existing encryption used an insufficient key strengh and had no authnetication. We now derive the key from 300,000 rounds of PBKDF2, encrypt with AES-CBC and authenticate data integrity with a SHA-256 HMAC.
---
 package.json           |  2 +-
 routes/encryption.js   | 11 +++++++++++
 routes/shepherd.js     |  1 -
 routes/shepherd/pin.js | 27 ++++++++++++---------------
 4 files changed, 24 insertions(+), 17 deletions(-)
 create mode 100644 routes/encryption.js

diff --git a/package.json b/package.json
index 23bbbd0..63357e2 100644
--- a/package.json
+++ b/package.json
@@ -46,10 +46,10 @@
     "fix-path": "^2.1.0",
     "fs-extra": "^4.0.2",
     "graceful-fs": "^4.1.11",
+    "iocane": "^1.0.0",
     "js-sha256": "^0.7.1",
     "lz-string": "^1.4.4",
     "marketmaker": "git://github.com/pbca26/marketmaker",
-    "nodejs-aes256": "^1.0.1",
     "passwd-strength": "git+https://github.com/pbca26/passwd-strength.git",
     "portscanner": "^2.1.1",
     "ps-node": "^0.1.5",
diff --git a/routes/encryption.js b/routes/encryption.js
new file mode 100644
index 0000000..3854f03
--- /dev/null
+++ b/routes/encryption.js
@@ -0,0 +1,11 @@
+'use strict';
+const {createSession} = require('iocane');
+
+const session = createSession()
+	.use('cbc')
+	.setDerivationRounds(300000);
+
+module.exports = {
+	encrypt: session.encrypt.bind(session),
+	decrypt: session.decrypt.bind(session),
+};
diff --git a/routes/shepherd.js b/routes/shepherd.js
index c3e8b07..c13049f 100644
--- a/routes/shepherd.js
+++ b/routes/shepherd.js
@@ -11,7 +11,6 @@ shepherd._fs = require('graceful-fs');
 shepherd.md5 = require('./md5.js');
 shepherd.request = require('request');
 shepherd.portscanner = require('portscanner');
-shepherd.aes256 = require('nodejs-aes256');
 shepherd.AdmZip = require('adm-zip');
 shepherd.remoteFileSize = require('remote-file-size');
 shepherd.Promise = require('bluebird');
diff --git a/routes/shepherd/pin.js b/routes/shepherd/pin.js
index 824bb32..20a10c1 100644
--- a/routes/shepherd/pin.js
+++ b/routes/shepherd/pin.js
@@ -1,5 +1,5 @@
 const fs = require('fs-extra');
-const aes256 = require('nodejs-aes256');
+const {encrypt, decrypt} = require('./../encryption');
 const passwdStrength = require('passwd-strength');
 const bitcoin = require('bitcoinjs-lib');
 const sha256 = require('js-sha256');
@@ -10,7 +10,7 @@ module.exports = (shepherd) => {
    *  type: POST
    *  params: none
    */
-  shepherd.post('/encryptkey', (req, res, next) => {
+  shepherd.post('/encryptkey', async (req, res, next) => {
     if (shepherd.checkToken(req.body.token)) {
       if (req.body.key &&
           req.body.string) {
@@ -42,7 +42,7 @@ module.exports = (shepherd) => {
           const _customPinFilenameTest = /^[0-9a-zA-Z-_]+$/g;
 
           if (_customPinFilenameTest.test(pubkey)) {
-            const encryptedString = aes256.encrypt(req.body.key, req.body.string);
+            const encryptedString = await encrypt(req.body.string, req.body.key);
 
             fs.writeFile(`${shepherd.agamaDir}/shepherd/pin/${pubkey}.pin`, encryptedString, (err) => {
               if (err) {
@@ -107,7 +107,7 @@ module.exports = (shepherd) => {
       if (req.body.key &&
           req.body.pubkey) {
         if (fs.existsSync(`${shepherd.agamaDir}/shepherd/pin/${req.body.pubkey}.pin`)) {
-          fs.readFile(`${shepherd.agamaDir}/shepherd/pin/${req.body.pubkey}.pin`, 'utf8', (err, data) => {
+          fs.readFile(`${shepherd.agamaDir}/shepherd/pin/${req.body.pubkey}.pin`, 'utf8', async (err, data) => {
             if (err) {
               const errorObj = {
                 msg: 'error',
@@ -116,21 +116,18 @@ module.exports = (shepherd) => {
 
               res.end(JSON.stringify(errorObj));
             } else {
-              const encryptedKey = aes256.decrypt(req.body.key, data);
-              // test if stored encrypted passphrase is decrypted correctly
-              // if not then the key is wrong
-              const _regexTest = encryptedKey.match(/^[0-9a-zA-Z ]+$/g);
-              let returnObj;
 
-              if (!_regexTest) {
+              let returnObj;
+              try {
+                const decryptedKey = await decrypt(data, req.body.key);
                 returnObj = {
-                  msg: 'error',
-                  result: 'wrong key',
+                  msg: 'success',
+                  result: decryptedKey,
                 };
-              } else {
+              } catch (error) {
                 returnObj = {
-                  msg: 'success',
-                  result: encryptedKey,
+                  msg: 'error',
+                  result: 'wrong key',
                 };
               }