This repository has been archived on 2022-09-21. You can view files and clone it, but cannot push or open issues or pull requests.
converse.js/src/plugins/omemo/utils.js

541 lines
21 KiB
JavaScript

/* global libsignal */
import difference from 'lodash-es/difference';
import log from '@converse/headless/log';
import { __ } from 'i18n';
import { _converse, converse, api } from '@converse/headless/core';
import { html } from 'lit';
import { initStorage } from '@converse/headless/shared/utils.js';
const { Strophe, sizzle, u } = converse.env;
const TAG_LENGTH = 128;
const KEY_ALGO = {
'name': 'AES-GCM',
'length': 128
};
export const omemo = {
async encryptMessage (plaintext) {
// The client MUST use fresh, randomly generated key/IV pairs
// with AES-128 in Galois/Counter Mode (GCM).
// For GCM a 12 byte IV is strongly suggested as other IV lengths
// will require additional calculations. In principle any IV size
// can be used as long as the IV doesn't ever repeat. NIST however
// suggests that only an IV size of 12 bytes needs to be supported
// by implementations.
//
// https://crypto.stackexchange.com/questions/26783/ciphertext-and-tag-size-and-iv-transmission-with-aes-in-gcm-mode
const iv = crypto.getRandomValues(new window.Uint8Array(12)),
key = await crypto.subtle.generateKey(KEY_ALGO, true, ['encrypt', 'decrypt']),
algo = {
'name': 'AES-GCM',
'iv': iv,
'tagLength': TAG_LENGTH
},
encrypted = await crypto.subtle.encrypt(algo, key, u.stringToArrayBuffer(plaintext)),
length = encrypted.byteLength - ((128 + 7) >> 3),
ciphertext = encrypted.slice(0, length),
tag = encrypted.slice(length),
exported_key = await crypto.subtle.exportKey('raw', key);
return {
'key': exported_key,
'tag': tag,
'key_and_tag': u.appendArrayBuffer(exported_key, tag),
'payload': u.arrayBufferToBase64(ciphertext),
'iv': u.arrayBufferToBase64(iv)
};
},
async decryptMessage (obj) {
const key_obj = await crypto.subtle.importKey('raw', obj.key, KEY_ALGO, true, ['encrypt', 'decrypt']);
const cipher = u.appendArrayBuffer(u.base64ToArrayBuffer(obj.payload), obj.tag);
const algo = {
'name': 'AES-GCM',
'iv': u.base64ToArrayBuffer(obj.iv),
'tagLength': TAG_LENGTH
};
return u.arrayBufferToString(await crypto.subtle.decrypt(algo, key_obj, cipher));
}
}
export function parseEncryptedMessage (stanza, attrs) {
if (attrs.is_encrypted && attrs.encrypted.key) {
// https://xmpp.org/extensions/xep-0384.html#usecases-receiving
if (attrs.encrypted.prekey === true) {
return decryptPrekeyWhisperMessage(attrs);
} else {
return decryptWhisperMessage(attrs);
}
} else {
return attrs;
}
}
export function onChatBoxesInitialized () {
_converse.chatboxes.on('add', chatbox => {
checkOMEMOSupported(chatbox);
if (chatbox.get('type') === _converse.CHATROOMS_TYPE) {
chatbox.occupants.on('add', o => onOccupantAdded(chatbox, o));
chatbox.features.on('change', () => checkOMEMOSupported(chatbox));
}
});
}
export function onChatInitialized (el) {
el.listenTo(el.model.messages, 'add', message => {
if (message.get('is_encrypted') && !message.get('is_error')) {
el.model.save('omemo_supported', true);
}
});
el.listenTo(el.model, 'change:omemo_supported', () => {
if (!el.model.get('omemo_supported') && el.model.get('omemo_active')) {
el.model.set('omemo_active', false);
} else {
// Manually trigger an update, setting omemo_active to
// false above will automatically trigger one.
el.querySelector('converse-chat-toolbar')?.requestUpdate();
}
});
el.listenTo(el.model, 'change:omemo_active', () => {
el.querySelector('converse-chat-toolbar').requestUpdate();
});
}
export function getSessionCipher (jid, id) {
const address = new libsignal.SignalProtocolAddress(jid, id);
return new window.libsignal.SessionCipher(_converse.omemo_store, address);
}
async function handleDecryptedWhisperMessage (attrs, key_and_tag) {
const encrypted = attrs.encrypted;
const devicelist = _converse.devicelists.getDeviceList(attrs.from);
await devicelist._devices_promise;
let device = devicelist.get(encrypted.device_id);
if (!device) {
device = await devicelist.devices.create({ 'id': encrypted.device_id, 'jid': attrs.from }, { 'promise': true });
}
if (encrypted.payload) {
const key = key_and_tag.slice(0, 16);
const tag = key_and_tag.slice(16);
const result = await omemo.decryptMessage(Object.assign(encrypted, { 'key': key, 'tag': tag }));
device.save('active', true);
return result;
}
}
function getDecryptionErrorAttributes (e) {
if (api.settings.get('loglevel') === 'debug') {
return {
'error_text':
__('Sorry, could not decrypt a received OMEMO message due to an error.') + ` ${e.name} ${e.message}`,
'error_type': 'Decryption',
'is_ephemeral': true,
'is_error': true,
'type': 'error'
};
} else {
return {};
}
}
async function decryptPrekeyWhisperMessage (attrs) {
const session_cipher = getSessionCipher(attrs.from, parseInt(attrs.encrypted.device_id, 10));
const key = u.base64ToArrayBuffer(attrs.encrypted.key);
let key_and_tag;
try {
key_and_tag = await session_cipher.decryptPreKeyWhisperMessage(key, 'binary');
} catch (e) {
// TODO from the XEP:
// There are various reasons why decryption of an
// OMEMOKeyExchange or an OMEMOAuthenticatedMessage
// could fail. One reason is if the message was
// received twice and already decrypted once, in this
// case the client MUST ignore the decryption failure
// and not show any warnings/errors. In all other cases
// of decryption failure, clients SHOULD respond by
// forcibly doing a new key exchange and sending a new
// OMEMOKeyExchange with a potentially empty SCE
// payload. By building a new session with the original
// sender this way, the invalid session of the original
// sender will get overwritten with this newly created,
// valid session.
log.error(`${e.name} ${e.message}`);
return Object.assign(attrs, getDecryptionErrorAttributes(e));
}
// TODO from the XEP:
// When a client receives the first message for a given
// ratchet key with a counter of 53 or higher, it MUST send
// a heartbeat message. Heartbeat messages are normal OMEMO
// encrypted messages where the SCE payload does not include
// any elements. These heartbeat messages cause the ratchet
// to forward, thus consequent messages will have the
// counter restarted from 0.
try {
const plaintext = await handleDecryptedWhisperMessage(attrs, key_and_tag);
await _converse.omemo_store.generateMissingPreKeys();
await _converse.omemo_store.publishBundle();
if (plaintext) {
return Object.assign(attrs, { 'plaintext': plaintext });
} else {
return Object.assign(attrs, { 'is_only_key': true });
}
} catch (e) {
log.error(`${e.name} ${e.message}`);
return Object.assign(attrs, getDecryptionErrorAttributes(e));
}
}
async function decryptWhisperMessage (attrs) {
const from_jid = attrs.from_muc ? attrs.from_real_jid : attrs.from;
if (!from_jid) {
Object.assign(attrs, {
'error_text': __("Sorry, could not decrypt a received OMEMO because we don't have the JID for that user."),
'error_type': 'Decryption',
'is_ephemeral': false,
'is_error': true,
'type': 'error'
});
}
const session_cipher = getSessionCipher(from_jid, parseInt(attrs.encrypted.device_id, 10));
const key = u.base64ToArrayBuffer(attrs.encrypted.key);
try {
const key_and_tag = await session_cipher.decryptWhisperMessage(key, 'binary');
const plaintext = await handleDecryptedWhisperMessage(attrs, key_and_tag);
return Object.assign(attrs, { 'plaintext': plaintext });
} catch (e) {
log.error(`${e.name} ${e.message}`);
return Object.assign(attrs, getDecryptionErrorAttributes(e));
}
}
export function addKeysToMessageStanza (stanza, dicts, iv) {
for (const i in dicts) {
if (Object.prototype.hasOwnProperty.call(dicts, i)) {
const payload = dicts[i].payload;
const device = dicts[i].device;
const prekey = 3 == parseInt(payload.type, 10);
stanza.c('key', { 'rid': device.get('id') }).t(btoa(payload.body));
if (prekey) {
stanza.attrs({ 'prekey': prekey });
}
stanza.up();
if (i == dicts.length - 1) {
stanza
.c('iv')
.t(iv)
.up()
.up();
}
}
}
return Promise.resolve(stanza);
}
/**
* Given an XML element representing a user's OMEMO bundle, parse it
* and return a map.
*/
export function parseBundle (bundle_el) {
const signed_prekey_public_el = bundle_el.querySelector('signedPreKeyPublic');
const signed_prekey_signature_el = bundle_el.querySelector('signedPreKeySignature');
const prekeys = sizzle(`prekeys > preKeyPublic`, bundle_el).map(el => ({
'id': parseInt(el.getAttribute('preKeyId'), 10),
'key': el.textContent
}));
return {
'identity_key': bundle_el.querySelector('identityKey').textContent.trim(),
'signed_prekey': {
'id': parseInt(signed_prekey_public_el.getAttribute('signedPreKeyId'), 10),
'public_key': signed_prekey_public_el.textContent,
'signature': signed_prekey_signature_el.textContent
},
'prekeys': prekeys
};
}
export async function generateFingerprint (device) {
if (device.get('bundle')?.fingerprint) {
return;
}
const bundle = await device.getBundle();
bundle['fingerprint'] = u.arrayBufferToHex(u.base64ToArrayBuffer(bundle['identity_key']));
device.save('bundle', bundle);
device.trigger('change:bundle'); // Doesn't get triggered automatically due to pass-by-reference
}
export async function getDevicesForContact (jid) {
await api.waitUntil('OMEMOInitialized');
const devicelist = _converse.devicelists.get(jid) || _converse.devicelists.create({ 'jid': jid });
await devicelist.fetchDevices();
return devicelist.devices;
}
export function generateDeviceID () {
/* Generates a device ID, making sure that it's unique */
const existing_ids = _converse.devicelists.get(_converse.bare_jid).devices.pluck('id');
let device_id = libsignal.KeyHelper.generateRegistrationId();
// Before publishing a freshly generated device id for the first time,
// a device MUST check whether that device id already exists, and if so, generate a new one.
let i = 0;
while (existing_ids.includes(device_id)) {
device_id = libsignal.KeyHelper.generateRegistrationId();
i++;
if (i === 10) {
throw new Error('Unable to generate a unique device ID');
}
}
return device_id.toString();
}
async function buildSession (device) {
// TODO: check device-get('jid') versus the 'from' attribute which is used
// to build a session when receiving an encrypted message in a MUC.
// https://github.com/conversejs/converse.js/issues/1481#issuecomment-509183431
const address = new libsignal.SignalProtocolAddress(device.get('jid'), device.get('id'));
const sessionBuilder = new libsignal.SessionBuilder(_converse.omemo_store, address);
const prekey = device.getRandomPreKey();
const bundle = await device.getBundle();
return sessionBuilder.processPreKey({
'registrationId': parseInt(device.get('id'), 10),
'identityKey': u.base64ToArrayBuffer(bundle.identity_key),
'signedPreKey': {
'keyId': bundle.signed_prekey.id, // <Number>
'publicKey': u.base64ToArrayBuffer(bundle.signed_prekey.public_key),
'signature': u.base64ToArrayBuffer(bundle.signed_prekey.signature)
},
'preKey': {
'keyId': prekey.id, // <Number>
'publicKey': u.base64ToArrayBuffer(prekey.key)
}
});
}
export async function getSession (device) {
if (!device.get('bundle')) {
log.error(`Could not build an OMEMO session for device ${device.get('id')} because we don't have its bundle`);
return null;
}
const address = new libsignal.SignalProtocolAddress(device.get('jid'), device.get('id'));
const session = await _converse.omemo_store.loadSession(address.toString());
if (session) {
return session;
} else {
try {
const session = await buildSession(device);
return session;
} catch (e) {
log.error(`Could not build an OMEMO session for device ${device.get('id')}`);
log.error(e);
return null;
}
}
}
function updateBundleFromStanza (stanza) {
const items_el = sizzle(`items`, stanza).pop();
if (!items_el || !items_el.getAttribute('node').startsWith(Strophe.NS.OMEMO_BUNDLES)) {
return;
}
const device_id = items_el.getAttribute('node').split(':')[1];
const jid = stanza.getAttribute('from');
const bundle_el = sizzle(`item > bundle`, items_el).pop();
const devicelist = _converse.devicelists.getDeviceList(jid);
const device = devicelist.devices.get(device_id) || devicelist.devices.create({ 'id': device_id, 'jid': jid });
device.save({ 'bundle': parseBundle(bundle_el) });
}
function updateDevicesFromStanza (stanza) {
const items_el = sizzle(`items[node="${Strophe.NS.OMEMO_DEVICELIST}"]`, stanza).pop();
if (!items_el) {
return;
}
const device_selector = `item list[xmlns="${Strophe.NS.OMEMO}"] device`;
const device_ids = sizzle(device_selector, items_el).map(d => d.getAttribute('id'));
const jid = stanza.getAttribute('from');
const devicelist = _converse.devicelists.getDeviceList(jid);
const devices = devicelist.devices;
const removed_ids = difference(devices.pluck('id'), device_ids);
removed_ids.forEach(id => {
if (jid === _converse.bare_jid && id === _converse.omemo_store.get('device_id')) {
return; // We don't set the current device as inactive
}
devices.get(id).save('active', false);
});
device_ids.forEach(device_id => {
const device = devices.get(device_id);
if (device) {
device.save('active', true);
} else {
devices.create({ 'id': device_id, 'jid': jid });
}
});
if (u.isSameBareJID(jid, _converse.bare_jid)) {
// Make sure our own device is on the list
// (i.e. if it was removed, add it again).
devicelist.publishCurrentDevice(device_ids);
}
}
export function registerPEPPushHandler () {
// Add a handler for devices pushed from other connected clients
_converse.connection.addHandler(
message => {
try {
if (sizzle(`event[xmlns="${Strophe.NS.PUBSUB}#event"]`, message).length) {
updateDevicesFromStanza(message);
updateBundleFromStanza(message);
}
} catch (e) {
log.error(e.message);
}
return true;
},
null,
'message',
'headline'
);
}
export function restoreOMEMOSession () {
if (_converse.omemo_store === undefined) {
const id = `converse.omemosession-${_converse.bare_jid}`;
_converse.omemo_store = new _converse.OMEMOStore({ id });
initStorage(_converse.omemo_store, id);
}
return _converse.omemo_store.fetchSession();
}
function fetchDeviceLists () {
return new Promise((success, error) => _converse.devicelists.fetch({ success, 'error': (m, e) => error(e) }));
}
async function fetchOwnDevices () {
await fetchDeviceLists();
let own_devicelist = _converse.devicelists.get(_converse.bare_jid);
if (own_devicelist) {
own_devicelist.fetchDevices();
} else {
own_devicelist = await _converse.devicelists.create({ 'jid': _converse.bare_jid }, { 'promise': true });
}
return own_devicelist._devices_promise;
}
export async function initOMEMO () {
if (!_converse.config.get('trusted') || api.settings.get('clear_cache_on_logout')) {
log.warn('Not initializing OMEMO, since this browser is not trusted or clear_cache_on_logout is set to true');
return;
}
_converse.devicelists = new _converse.DeviceLists();
const id = `converse.devicelists-${_converse.bare_jid}`;
initStorage(_converse.devicelists, id);
try {
await fetchOwnDevices();
await restoreOMEMOSession();
await _converse.omemo_store.publishBundle();
} catch (e) {
log.error('Could not initialize OMEMO support');
log.error(e);
return;
}
/**
* Triggered once OMEMO support has been initialized
* @event _converse#OMEMOInitialized
* @example _converse.api.listen.on('OMEMOInitialized', () => { ... }); */
api.trigger('OMEMOInitialized');
}
async function onOccupantAdded (chatroom, occupant) {
if (occupant.isSelf() || !chatroom.features.get('nonanonymous') || !chatroom.features.get('membersonly')) {
return;
}
if (chatroom.get('omemo_active')) {
const supported = await _converse.contactHasOMEMOSupport(occupant.get('jid'));
if (!supported) {
chatroom.createMessage({
'message': __(
"%1$s doesn't appear to have a client that supports OMEMO. " +
'Encrypted chat will no longer be possible in this grouchat.',
occupant.get('nick')
),
'type': 'error'
});
chatroom.save({ 'omemo_active': false, 'omemo_supported': false });
}
}
}
async function checkOMEMOSupported (chatbox) {
let supported;
if (chatbox.get('type') === _converse.CHATROOMS_TYPE) {
await api.waitUntil('OMEMOInitialized');
supported = chatbox.features.get('nonanonymous') && chatbox.features.get('membersonly');
} else if (chatbox.get('type') === _converse.PRIVATE_CHAT_TYPE) {
supported = await _converse.contactHasOMEMOSupport(chatbox.get('jid'));
}
chatbox.set('omemo_supported', supported);
if (supported && api.settings.get('omemo_default')) {
chatbox.set('omemo_active', true);
}
}
function toggleOMEMO (ev) {
ev.stopPropagation();
ev.preventDefault();
const toolbar_el = u.ancestor(ev.target, 'converse-chat-toolbar');
if (!toolbar_el.model.get('omemo_supported')) {
let messages;
if (toolbar_el.model.get('type') === _converse.CHATROOMS_TYPE) {
messages = [
__(
'Cannot use end-to-end encryption in this groupchat, ' +
'either the groupchat has some anonymity or not all participants support OMEMO.'
)
];
} else {
messages = [
__(
"Cannot use end-to-end encryption because %1$s uses a client that doesn't support OMEMO.",
toolbar_el.model.contact.getDisplayName()
)
];
}
return api.alert('error', __('Error'), messages);
}
toolbar_el.model.save({ 'omemo_active': !toolbar_el.model.get('omemo_active') });
}
export function getOMEMOToolbarButton (toolbar_el, buttons) {
const model = toolbar_el.model;
const is_muc = model.get('type') === _converse.CHATROOMS_TYPE;
let title;
if (is_muc && model.get('omemo_supported')) {
const i18n_plaintext = __('Messages are being sent in plaintext');
const i18n_encrypted = __('Messages are sent encrypted');
title = model.get('omemo_active') ? i18n_encrypted : i18n_plaintext;
} else {
title = __(
'This groupchat needs to be members-only and non-anonymous in ' +
'order to support OMEMO encrypted messages'
);
}
buttons.push(html`
<button class="toggle-omemo" title="${title}" ?disabled=${!model.get('omemo_supported')} @click=${toggleOMEMO}>
<converse-icon
class="fa ${model.get('omemo_active') ? `fa-lock` : `fa-unlock`}"
path-prefix="${api.settings.get('assets_path')}"
size="1em"
color="${model.get('omemo_active') ? `var(--info-color)` : `var(--error-color)`}"
></converse-icon>
</button>
`);
return buttons;
}