Initial commit

background.js

@@ -0,0 +1,130 @@
+// state saved to restore data every time the popu is opened
+let state = {
+	iv: window.crypto.getRandomValues(new Uint8Array(12)),
+	salt: window.crypto.getRandomValues(new Uint8Array(16)),
+	key: null,
+	entries: []
+}
+
+let popup_port = null // communication channel with popup
+
+function b32decode(text)
+{
+	const up_text = text.toUpperCase()
+	let result = []
+	let lshift = 3
+	let carry = 0
+	for(const index in up_text)
+	{
+		const char = up_text[index]
+		if(char === '=')
+			break
+		let value = char.charCodeAt() - 65
+		if(value < 0)
+			value += 41
+		if(value < 0 || value > 31)
+			throw `Incorrect Base32 char '${text[index]}' at index ${index}`
+
+		if(lshift > 0) // next value is needed to complete the octet
+		{
+			carry += value << lshift
+			lshift -= 5
+			if(lshift === 0) // last value aligned with octet
+				carry = 0
+		}
+		else // getting the last octet' bits
+		{
+			result.push(carry + (value >>> (-lshift)))
+			carry = (value << (lshift + 8)) & 248 // if lshit is 0 this will always be 0
+			lshift += 3
+		}
+	}
+	if(carry !== 0)
+		result.push(carry)
+	return result
+}
+
+// Create encryption key from password
+async function setKey(password)
+{
+	const storage = await browser.storage.local.get()
+	if(storage.entries !== undefined && storage.iv !== undefined && storage.salt !== undefined)
+	{
+		state.iv = new Uint8Array(b32decode(storage.iv))
+		state.salt = new Uint8Array(b32decode(storage.salt))
+	}
+
+	let encoder = new TextEncoder();
+	const key_material = await window.crypto.subtle.importKey(
+		'raw',
+		encoder.encode(password),
+		'PBKDF2',
+		false,
+		['deriveKey'])
+	state.key = await window.crypto.subtle.deriveKey(
+		{
+			name: "PBKDF2",
+			salt: state.salt,
+			iterations: 20000,
+			hash: "SHA-256",
+		},
+		key_material,
+		{ "name": "AES-GCM", "length": 256},
+		true,
+		["encrypt", "decrypt"])
+	// If entries are set in the state we automatically restore them
+	if(storage.entries !== undefined)
+		restore(storage)
+	else
+		popup_port.postMessage(state)
+}
+
+// Decrypt entries saved in local storage
+async function restore(storage)
+{
+	try
+	{
+		let decrypted = await window.crypto.subtle.decrypt(
+			{
+				name: "AES-GCM",
+				iv: state.iv
+			},
+			state.key,
+			new Uint8Array(b32decode(storage.entries))
+		);
+
+		let decoder = new TextDecoder();
+		state.entries = JSON.parse(decoder.decode(decrypted))
+		popup_port.postMessage(state)
+	}
+	catch (error)
+	{
+		console.error('Cannot decrypt entries: wrong password')
+	}
+}
+
+function connected(port) {
+	popup_port = port
+	popup_port.onMessage.addListener((message) => {
+	  	if(message.command === 'init')
+		{
+			if(state.key === null)
+				popup_port.postMessage(state)
+			else
+				browser.storage.local.get().then((storage) => {
+					restore(storage)
+				})
+		}
+		else if(message.command === 'key')
+			setKey(message.password)
+		else if(message.command === 'logout')
+		{
+			state.key = null
+			state.entries = []
+		}
+		else
+			console.error(`Wrong message: ${message}`)
+	})
+ }
+
+ browser.runtime.onConnect.addListener(connected);