Server: Resolves #5738: Check for time drift when the server starts

.eslintignore

@@ -1176,9 +1176,9 @@ packages/lib/models/utils/paginationToSql.js.map
 packages/lib/models/utils/types.d.ts
 packages/lib/models/utils/types.js
 packages/lib/models/utils/types.js.map
-packages/lib/ntpDate.d.ts
+packages/lib/ntp.d.ts
-packages/lib/ntpDate.js
+packages/lib/ntp.js
-packages/lib/ntpDate.js.map
+packages/lib/ntp.js.map
 packages/lib/onedrive-api.d.ts
 packages/lib/onedrive-api.js
 packages/lib/onedrive-api.js.map

.gitignore

@@ -1159,9 +1159,9 @@ packages/lib/models/utils/paginationToSql.js.map
 packages/lib/models/utils/types.d.ts
 packages/lib/models/utils/types.js
 packages/lib/models/utils/types.js.map
-packages/lib/ntpDate.d.ts
+packages/lib/ntp.d.ts
-packages/lib/ntpDate.js
+packages/lib/ntp.js
-packages/lib/ntpDate.js.map
+packages/lib/ntp.js.map
 packages/lib/onedrive-api.d.ts
 packages/lib/onedrive-api.js
 packages/lib/onedrive-api.js.map

packages/lib/ntp.ts

@@ -0,0 +1,61 @@
+import shim from './shim';
+const ntpClient_ = require('./vendor/ntp-client');
+
+const server = {
+	domain: 'pool.ntp.org',
+	port: 123,
+};
+
+function ntpClient() {
+	ntpClient_.dgram = shim.dgram();
+	return ntpClient_;
+}
+
+export async function getNetworkTime(): Promise<Date> {
+	return new Promise(function(resolve: Function, reject: Function) {
+		ntpClient().getNetworkTime(server.domain, server.port, function(error: any, date: Date) {
+			if (error) {
+				reject(error);
+				return;
+			}
+
+			resolve(date);
+		});
+	});
+}
+
+export async function getDeviceTimeDrift(): Promise<number> {
+	let ntpTime: Date = null;
+	try {
+		ntpTime = await getNetworkTime();
+	} catch (error) {
+		error.message = `Cannot retrieve the network time: ${error.message}`;
+		throw error;
+	}
+
+	return ntpTime.getTime() - Date.now();
+}
+
+// export default async function(): Promise<Date> {
+// 	if (shouldSyncTime()) {
+// 		const release = await fetchingTimeMutex.acquire();
+
+// 		try {
+// 			if (shouldSyncTime()) {
+// 				const date = await networkTime();
+// 				nextSyncTime = Date.now() + 60 * 1000;
+// 				timeOffset = date.getTime() - Date.now();
+// 			}
+// 		} catch (error) {
+// 			logger.warn('Could not get NTP time - falling back to device time:', error);
+// 			// Fallback to device time since
+// 			// most of the time it's actually correct
+// 			nextSyncTime = Date.now() + 20 * 1000;
+// 			timeOffset = 0;
+// 		} finally {
+// 			release();
+// 		}
+// 	}
+
+// 	return new Date(Date.now() + timeOffset);
+// }

packages/lib/ntpDate.ts

@@ -1,59 +0,0 @@
-const ntpClient = require('./vendor/ntp-client');
-import Logger from './Logger';
-const Mutex = require('async-mutex').Mutex;
-
-let nextSyncTime = 0;
-let timeOffset = 0;
-let logger = new Logger();
-
-const fetchingTimeMutex = new Mutex();
-
-const server = {
-	domain: 'pool.ntp.org',
-	port: 123,
-};
-
-async function networkTime(): Promise<Date> {
-	return new Promise(function(resolve: Function, reject: Function) {
-		ntpClient.getNetworkTime(server.domain, server.port, function(error: any, date: Date) {
-			if (error) {
-				reject(error);
-				return;
-			}
-
-			resolve(date);
-		});
-	});
-}
-
-function shouldSyncTime() {
-	return !nextSyncTime || Date.now() > nextSyncTime;
-}
-
-export function setLogger(v: any) {
-	logger = v;
-}
-
-export default async function(): Promise<Date> {
-	if (shouldSyncTime()) {
-		const release = await fetchingTimeMutex.acquire();
-
-		try {
-			if (shouldSyncTime()) {
-				const date = await networkTime();
-				nextSyncTime = Date.now() + 60 * 1000;
-				timeOffset = date.getTime() - Date.now();
-			}
-		} catch (error) {
-			logger.warn('Could not get NTP time - falling back to device time:', error);
-			// Fallback to device time since
-			// most of the time it's actually correct
-			nextSyncTime = Date.now() + 20 * 1000;
-			timeOffset = 0;
-		} finally {
-			release();
-		}
-	}
-
-	return new Date(Date.now() + timeOffset);
-}

packages/lib/shim-init-node.js

@@ -16,6 +16,7 @@ const https = require('https');
 const toRelative = require('relative');
 const timers = require('timers');
 const zlib = require('zlib');
+const dgram = require('dgram');
 
 function fileExists(filePath) {
 	try {
@@ -93,6 +94,10 @@ function shimInit(options = null) {
 		return shim.fsDriver_;
 	};
 
+	shim.dgram = () => {
+		return dgram;
+	};
+
 	if (options.React) {
 		shim.react = () => {
 			return options.React;

packages/lib/shim.ts

@@ -333,6 +333,10 @@ const shim = {
 		return react_;
 	},
 
+	dgram: () => {
+		throw new Error('Not implemented');
+	},
+
 	platformSupportsKeyChain: () => {
 		// keytar throws an error when system keychain is not present; even
 		// when keytar itself is installed. try/catch to ensure system

packages/lib/vendor/ntp-client.js

@@ -44,8 +44,8 @@ const Buffer = require('buffer').Buffer;
 
         if (!exports.dgram) throw new Error('dgram package has not been set!!');
 
-        var client = exports.dgram.createSocket("udp4"),
+        var client = exports.dgram.createSocket("udp4");
-            ntpData = new Buffer(48);
+        var ntpData = Buffer.alloc(48); // new Buffer(48);
 
         // RFC 2030 -> LI = 0 (no warning, 2 bits), VN = 3 (IPv4 only, 3 bits), Mode = 3 (Client Mode, 3 bits) -> 1 byte
         // -> rtol(LI, 6) ^ rotl(VN, 3) ^ rotl(Mode, 0)

packages/server/src/app.ts

@@ -8,6 +8,7 @@ import config, { initConfig, runningInDocker } from './config';
 import { migrateLatest, waitForConnection, sqliteDefaultDir, latestMigration } from './db';
 import { AppContext, Env, KoaNext } from './utils/types';
 import FsDriverNode from '@joplin/lib/fs-driver-node';
+import { getDeviceTimeDrift } from '@joplin/lib/ntp';
 import routeHandler from './middleware/routeHandler';
 import notificationHandler from './middleware/notificationHandler';
 import ownerHandler from './middleware/ownerHandler';
@@ -249,6 +250,13 @@ async function main() {
 		runCommandAndExitApp = false;
 
 		appLogger().info(`Starting server v${config().appVersion} (${env}) on port ${config().port} and PID ${process.pid}...`);
+
+		const timeDrift = await getDeviceTimeDrift();
+		if (Math.abs(timeDrift) > config().maxTimeDrift) {
+			throw new Error(`The device time drift is ${timeDrift}ms (Max allowed: ${config().maxTimeDrift}ms) - cannot continue as it could cause data loss and conflicts on the sync clients. You may increase env var MAX_TIME_DRIFT to pass the check.`);
+		}
+
+		appLogger().info(`NTP time offset: ${timeDrift}ms`);
 		appLogger().info('Running in Docker:', runningInDocker());
 		appLogger().info('Public base URL:', config().baseUrl);
 		appLogger().info('API base URL:', config().apiBaseUrl);

packages/server/src/config.ts

@@ -134,6 +134,7 @@ export async function initConfig(envType: Env, env: EnvVariables, overrides: any
 		storageDriver: parseStorageDriverConnectionString(env.STORAGE_DRIVER),
 		storageDriverFallback: parseStorageDriverConnectionString(env.STORAGE_DRIVER_FALLBACK),
 		itemSizeHardLimit: 250000000, // Beyond this the Postgres driver will crash the app
+		maxTimeDrift: env.MAX_TIME_DRIFT,
 		...overrides,
 	};
 }

packages/server/src/env.ts

@@ -16,6 +16,7 @@ const defaultEnvValues: EnvVariables = {
 	ERROR_STACK_TRACES: false,
 	COOKIES_SECURE: false,
 	RUNNING_IN_DOCKER: false,
+	MAX_TIME_DRIFT: 10,
 
 	// ==================================================
 	// URL config
@@ -85,6 +86,7 @@ export interface EnvVariables {
 	ERROR_STACK_TRACES: boolean;
 	COOKIES_SECURE: boolean;
 	RUNNING_IN_DOCKER: boolean;
+	MAX_TIME_DRIFT: number;
 
 	APP_BASE_URL: string;
 	USER_CONTENT_BASE_URL: string;

packages/server/src/utils/types.ts

@@ -160,6 +160,7 @@ export interface Config {
 	storageDriver: StorageDriverConfig;
 	storageDriverFallback: StorageDriverConfig;
 	itemSizeHardLimit: number;
+	maxTimeDrift: number;
 }
 
 export enum HttpMethod {