From db738e978a929c8eeb300723e405efdfa355d095 Mon Sep 17 00:00:00 2001
From: Jerko Steiner <jerko.steiner@gmail.com>
Date: Tue, 7 Jan 2020 18:12:00 +0100
Subject: [PATCH] Generate ECDH key pairs on application startup.

Potential TODO:

- share the keys with other peers.
- think about if it makes sense to encrypt signal messages.
---
 src/client/actions/CallActions.ts | 53 +++++++++++++++++++++++++++++++
 src/client/db/identities.test.ts  | 34 ++++++++++++++++++++
 src/client/db/identities.ts       | 53 +++++++++++++++++++++++++++++++
 src/client/db/index.ts            |  1 +
 4 files changed, 141 insertions(+)
 create mode 100644 src/client/db/identities.test.ts
 create mode 100644 src/client/db/identities.ts

diff --git a/src/client/actions/CallActions.ts b/src/client/actions/CallActions.ts
index 3c7aa14..aff4884 100644
--- a/src/client/actions/CallActions.ts
+++ b/src/client/actions/CallActions.ts
@@ -1,9 +1,15 @@
+import _debug from 'debug'
 import socket from '../socket'
 import { Dispatch, ThunkResult } from '../store'
 import { callId } from '../window'
 import { ClientSocket } from '../socket'
 import * as NotifyActions from './NotifyActions'
 import * as SocketActions from './SocketActions'
+import { generateECDHKeyPair, exportKey } from '../crypto'
+import { getIdentity, Identity, saveIdentity } from '../db'
+import { ME } from '../constants'
+
+const debug = _debug('peercalls')
 
 export interface InitAction {
   type: 'INIT'
@@ -22,6 +28,11 @@ export const init = (): ThunkResult<Promise<void>> =>
 async (dispatch, getState) => {
   const socket = await dispatch(connect())
 
+  const keyPair = await dispatch(findOrCreateEncryptionKeys())
+  const publicKey = keyPair && await exportKey(keyPair.publicKey)
+  // TODO use publicKey
+  publicKey
+
   dispatch(SocketActions.handshake({
     socket,
     roomName: callId,
@@ -43,3 +54,45 @@ export const connect = () => (dispatch: Dispatch) => {
     })
   })
 }
+
+export const findOrCreateEncryptionKeys = () => async (
+  dispatch: Dispatch,
+): Promise<CryptoKeyPair | undefined> => {
+
+  let identity: Identity | undefined
+  try {
+    identity = await getIdentity(ME)
+  } catch (err) {
+    dispatch(NotifyActions.error('This browser does not support IndexedDB'))
+    debug('IndexedDB error: %s', err)
+    return undefined
+  }
+
+  if (identity && identity.privateKey) {
+    dispatch(NotifyActions.info('Using encryption keys from IndexedDB'))
+    return {
+      privateKey: identity.privateKey,
+      publicKey: identity.publicKey,
+    }
+  }
+
+  let keyPair: CryptoKeyPair
+  try {
+    keyPair = await generateECDHKeyPair()
+  } catch (err) {
+    dispatch(NotifyActions.error('Unable to generate encryption keys'))
+    debug('Unable to generate encryption keys: %s', err)
+    return undefined
+  }
+  const { privateKey, publicKey } = keyPair
+
+  identity = {
+    id: ME,
+    privateKey,
+    publicKey,
+  }
+
+  await saveIdentity(identity)
+
+  return keyPair
+}
diff --git a/src/client/db/identities.test.ts b/src/client/db/identities.test.ts
new file mode 100644
index 0000000..0dbd6f7
--- /dev/null
+++ b/src/client/db/identities.test.ts
@@ -0,0 +1,34 @@
+import { getIdentity, saveIdentity } from './identities'
+import { promisify } from './promisify'
+import { generateECDHKeyPair } from '../crypto'
+
+describe('identities', () => {
+
+  const TEST_DB = 'TEST_DB'
+
+  let keyPair: CryptoKeyPair
+  beforeEach(async () => {
+    keyPair = await generateECDHKeyPair()
+  })
+  afterEach(async () => {
+    await promisify(window.indexedDB.deleteDatabase(TEST_DB))
+  })
+
+  describe('getIdentity', () => {
+    it('reads saved identity', async () => {
+      const identity = {
+        id: 'one',
+        ...keyPair,
+      }
+      await saveIdentity(identity)
+      const identity2 = await getIdentity(identity.id)
+      expect(identity2).not.toBe(identity)
+      expect(identity2).toEqual(identity)
+    })
+    it('does not fail when not found', async () => {
+      const identity = await getIdentity('notfound')
+      expect(identity).toBe(undefined)
+    })
+  })
+
+})
diff --git a/src/client/db/identities.ts b/src/client/db/identities.ts
new file mode 100644
index 0000000..9cbac3a
--- /dev/null
+++ b/src/client/db/identities.ts
@@ -0,0 +1,53 @@
+import { open } from './open'
+import { promisify } from './promisify'
+import { exportKey, importKey } from '../crypto'
+
+export interface Identity {
+  id: string
+  publicKey: CryptoKey
+  privateKey?: CryptoKey
+}
+
+export interface StoredIdentity {
+  id: string
+  publicKey: JsonWebKey
+  privateKey?: JsonWebKey
+}
+
+const DB = 'PEERCALLS'
+
+export async function getIdentity(id: string): Promise<Identity | undefined> {
+  const db = await open(DB, 1)
+  let stored: StoredIdentity | undefined
+  try {
+    const tx = db.transaction('identities', 'readonly')
+    const store = tx.objectStore('identities')
+    stored = await promisify(store.get(id))
+  } finally {
+    db.close()
+  }
+
+  return stored && {
+    id: stored.id,
+    privateKey: stored.privateKey && await importKey(stored.privateKey),
+    publicKey: await importKey(stored.publicKey),
+  }
+}
+
+export async function saveIdentity(identity: Identity): Promise<void> {
+  const stored = {
+    id: identity.id,
+    privateKey: identity.privateKey && await exportKey(identity.privateKey),
+    publicKey: await exportKey(identity.publicKey),
+  }
+
+  const db = await open(DB, 1)
+  try {
+    const tx = db.transaction('identities', 'readwrite')
+    const store = tx.objectStore('identities')
+    await promisify(store.put(stored))
+    await promisify(tx)
+  } finally {
+    db.close()
+  }
+}
diff --git a/src/client/db/index.ts b/src/client/db/index.ts
index 34ddef4..676d3ba 100644
--- a/src/client/db/index.ts
+++ b/src/client/db/index.ts
@@ -1,2 +1,3 @@
 export { promisify } from './promisify'
 export { open } from './open'
+export * from './identities'