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endpoints.es
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endpoints.es
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/*!
* Copyright (c) 2014-present Cliqz GmbH. All rights reserved.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/.
*/
import config from '../core/config';
import { fetch, Headers, Response, AbortController } from '../core/http';
import random, { randomInt } from '../core/crypto/random';
import logger from './logger';
import { TransportError, ServerError, NotReadyError, MsgTimeoutError } from './errors';
import { VERSION, ECDH_P256_AES_128_GCM } from './constants';
import { inflate } from '../core/zlib';
import { fromUTF8, toUTF8, toByteArray, toBase64, fromBase64 } from '../core/encoding';
import crypto from '../platform/crypto';
import LRU from '../core/LRU';
import pacemaker from '../core/services/pacemaker';
const MAX_PROXY_BUCKETS = 10;
const SECOND = 1000;
const { subtle } = crypto;
async function generateECDH() {
return subtle.generateKey(
{ name: 'ECDH', namedCurve: 'P-256' },
true,
['deriveKey']
);
}
async function deriveKey(serverPublicKey, clientPrivateKey) {
return subtle.deriveKey(
{ name: 'ECDH', namedCurve: 'P-256', public: serverPublicKey },
clientPrivateKey,
{ name: 'AES-GCM', length: 256 },
true,
['encrypt', 'decrypt']
);
}
async function exportKey(key) {
return new Uint8Array(await subtle.exportKey('raw', key));
}
async function sha256(data) {
return new Uint8Array(await subtle.digest({ name: 'SHA-256' }, data));
}
async function importAesKey(data) {
return subtle.importKey(
'raw',
data,
{ name: 'AES-GCM', length: 128 },
false,
['encrypt', 'decrypt']
);
}
async function encryptAES(iv, key, data) {
return new Uint8Array(await subtle.encrypt({ name: 'AES-GCM', iv, tagLength: 128 }, key, data));
}
async function decryptAES(iv, key, data) {
return new Uint8Array(await subtle.decrypt({ name: 'AES-GCM', iv, tagLength: 128 }, key, data));
}
async function encrypt(data, serverPublicKey) {
const { publicKey: clientPublicKey, privateKey } = await generateECDH();
const derivedKey = await deriveKey(serverPublicKey, privateKey);
const rawDerived = await exportKey(derivedKey);
const encryptionKey = (await sha256(rawDerived)).subarray(0, 16);
const iv = crypto.getRandomValues(new Uint8Array(12));
const aesKey = await importAesKey(encryptionKey);
const encrypted = await encryptAES(iv, aesKey, data);
return { iv, encrypted, clientPublicKey: await exportKey(clientPublicKey), aesKey };
}
function toRelativeTimeout(absoluteTimeout) {
if (!absoluteTimeout) {
return { timeoutInMs: undefined, isExpired: false };
}
const timeoutInMs = absoluteTimeout - Date.now();
return { timeoutInMs, isExpired: timeoutInMs <= 0 };
}
async function myfetch(url, { method = 'GET', body, publicKey = {}, timeoutInMs } = {}) {
// eslint-disable-next-line no-param-reassign
timeoutInMs = timeoutInMs || (60 * SECOND);
const abortController = new AbortController();
const headers = new Headers({ Version: VERSION.toString() });
const options = {
method,
headers,
credentials: 'omit',
cache: 'no-store',
redirect: 'manual',
signal: abortController.signal
};
if (body instanceof ArrayBuffer || ArrayBuffer.isView(body)) {
options.headers.append('Content-Type', 'application/octet-stream');
options.body = toByteArray(body);
} else if (body && typeof body === 'object') {
options.headers.append('Content-Type', 'application/json');
options.body = toUTF8(JSON.stringify(body));
}
let aesKey;
const { key, date } = publicKey;
if (key && options.body) {
const out = await encrypt(options.body, key);
const { iv, encrypted, clientPublicKey } = out;
aesKey = out.aesKey;
options.headers.append('Key-Date', date);
options.body = encrypted;
const encryption = new Uint8Array(1 + 65 + 12);
encryption.set(clientPublicKey, 1);
encryption.set(iv, 1 + 65);
encryption[0] = ECDH_P256_AES_128_GCM;
options.headers.append('Encryption', toBase64(encryption));
}
return new Promise(async (resolve, reject) => {
const timer = pacemaker.setTimeout(() => {
reject(new MsgTimeoutError(`Exceeded timeout of ${timeoutInMs / 1000} sec`));
abortController.abort();
}, timeoutInMs);
try {
let response;
try {
response = await fetch(url, options);
} catch (e) {
throw new ServerError(e);
}
const { status, statusText, ok } = response;
if (!ok) {
throw new ServerError(statusText);
}
if (aesKey && response.headers.get('Encryption-IV')) {
const encrypted = new Uint8Array(await response.arrayBuffer());
const iv = fromBase64(response.headers.get('Encryption-IV'));
const decrypted = await decryptAES(iv, aesKey, encrypted);
response = new Response(decrypted, { status, statusText });
}
resolve(response);
} catch (e) {
reject(e);
} finally {
pacemaker.clearTimeout(timer);
}
});
}
// Just to have all the endpoints in the same place.
export default class Endpoints {
constructor({ maxRetries = 3, urls = config.settings } = {}) {
this._reset();
this.maxRetries = maxRetries;
this.urls = urls;
this.proxyBuckets = new LRU(MAX_PROXY_BUCKETS);
}
_reset() {
const oldMessages = this.messages || [];
this.messages = [];
this.sendTimer = null;
this.unloaded = false;
oldMessages.forEach(x => x.reject(new NotReadyError('Request cancelled because of unload')));
}
get ENDPOINT_HPNV2_ANONYMOUS() {
return this.urls.ENDPOINT_HPNV2_ANONYMOUS;
}
get ENDPOINT_HPNV2_DIRECT() {
return this.urls.ENDPOINT_HPNV2_DIRECT;
}
get ENDPOINT_HPNV2_JOIN() {
return `${this.ENDPOINT_HPNV2_DIRECT}/join`;
}
get ENDPOINT_HPNV2_POST() {
return this.ENDPOINT_HPNV2_ANONYMOUS;
}
get ENDPOINT_HPNV2_CONFIG() {
// It is important that we never use the anonymous endpoint here!
// If /config requests would go through a 3rd party proxy, we would
// be open to man-in-the-middle attacks.
//
// The reason is that it breaks the Diffie-Hellman key exchange,
// as a malicious proxy could modify the server's public key.
// The consequence would be that a malicious proxy could trick
// the client into encrypting with a secret known to the proxy.
return `${this.ENDPOINT_HPNV2_DIRECT}/config`;
}
_scheduleSend() {
if (this.unloaded || this.sendTimer !== null) {
return;
}
this.sendTimer = pacemaker.setTimeout(() => {
const n = Math.floor(random() * this.messages.length);
const {
url,
msg,
cnt,
publicKey,
resolve,
reject,
absoluteTimeout
} = this.messages.splice(n, 1)[0];
myfetch(url, { method: 'POST', body: msg, publicKey })
.then(resolve, (e) => {
if (cnt < this.maxRetries) {
logger.log('Will retry sending msg after error', e);
this.messages.push({
url,
msg,
cnt: cnt + 1,
publicKey,
resolve,
reject,
absoluteTimeout
});
} else {
logger.warn('_scheduleSend failed (gave up after', this.maxRetries,
'retry attempts)', e);
reject(e);
}
})
.then(() => {
this.sendTimer = null;
if (this.messages.length > 0) {
this._scheduleSend();
}
});
}, 500 + Math.floor(random() * 1500)); // TODO: improve?
}
// When defined, proxyBucket is random string or number, "big enough" to avoid collisions
// Same proxyBucket will be routed via same proxy (e.g. for search queries)
async send(msg, { instant, proxyBucket, publicKey, absoluteTimeout } = {}) {
const MIN_PROXY_NUM = 1;
const MAX_PROXY_NUM = 100;
const NUM_PROXIES = MAX_PROXY_NUM - MIN_PROXY_NUM + 1;
const randBucket = (randomInt() % NUM_PROXIES) + MIN_PROXY_NUM;
const proxyNum = this.proxyBuckets.get(proxyBucket) || randBucket;
if (proxyBucket) {
this.proxyBuckets.set(proxyBucket, proxyNum);
}
const url = this.ENDPOINT_HPNV2_POST.replace('*', proxyNum);
if (instant) {
try {
const { timeoutInMs, isExpired } = toRelativeTimeout(absoluteTimeout);
if (isExpired) {
throw new MsgTimeoutError('dropping request because the absolute timeout expired');
}
const response = await myfetch(url, { method: 'POST', body: msg, publicKey, timeoutInMs });
let data = new Uint8Array(await response.arrayBuffer());
if (data[0] !== 0x7B) {
const size = (new DataView(data.buffer)).getUint32();
data = inflate(data.subarray(4, 4 + size));
}
const { status, body } = JSON.parse(fromUTF8(data));
return new Response(body, { status });
} catch (e) {
if (e instanceof ServerError) {
throw e;
}
throw new TransportError(e.message);
}
}
// non-instance message
const pendingSend = new Promise((resolve, reject) => {
this.messages.push({ url, msg, cnt: 0, publicKey, resolve, reject, absoluteTimeout });
});
this._scheduleSend();
// The server response is not too interesting, as it will always confirm
// with an empty response. Still, waiting for the response is useful
// to make sure that the server got the message, also we only will
// know for sure that the network request was successful.
await pendingSend;
return new Response();
}
async join(body) {
const response = await myfetch(this.ENDPOINT_HPNV2_JOIN, { method: 'POST', body });
return response.json();
}
async getConfig() {
return (await myfetch(this.ENDPOINT_HPNV2_CONFIG)).json();
}
unload() {
pacemaker.clearTimeout(this.sendTimer);
this._reset();
this.proxyBuckets.reset();
this.unloaded = true;
}
}