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Security

Install

npm install @bluelibs/security-bundle

Purpose

Security is one of the most important aspects when it comes to developing web apps, the impact of bad security can be business-disruptive, this is why Security was one of those modules which took a lot of time to design and everything has been carefully designed to fit a wide palette of applications.

We wanted to create a module that is database agnostic and helps us with:

  • Ability to create, enable/disable users
  • Ability to create authentication sessions for users
  • Ability to have dynamic fully-customisable authentication strategies (password, biometric, jwt, etc)
  • Fully-featured Permissioning System with Permission Hierarchies.

This module works with any database and you can have different persistance layers for each: Users, Sessions, Permissions. For example once your application becomes very large, you might want to store your Sessions inside redis for its raw speed. This is done by simply changing an abstraction layer and not lay a single finger on your code, everything will work.

Configuration

By default it uses an in-memory database as persistance for users/permission/sessions, which means that on every server-restart everything will be forgotten. Either implement your own persistance layers either use some already done such as: Security Mongo Bundle

import { SecurityBundle } from "@bluelibs/security-bundle";
new SecurityBundle({  // The permission tree (more on it below), is how you configure the role hierarchy in your app  permissionTree: {    SUPER_ADMIN: {      POST_ADMIN: 1,    },    POST_ADMIN: 1,  },
  // Configure some default session attributes, like expiration and automated cleanup  session: {    expiresIn: "14d", // (zeit/ms format) How long to have by default an active session/    cleanup: true, // Should we clean expired sessions from the database    cleanupInterval: "7d", // (zeit/ms format) How frequently to do cleanup of expired sessions?  },});

Persistance Layers

In our current bundle we refer to persistence layers, as the services which lets us find, insert, update and remove different aspects of our models User, Permission, Session.

You can specify these permission layers in the bundle's config:

import { SecurityBundle, IUserPersistance } from "@bluelibs/security-bundle";
class MyUserPersistance implements IUserPersistance {  // all the methods to satisfy the IUserPersistance interface}
new SecurityBundle({  userPersistance: MyUserPersistance,});
// OR
class AppBundle extends Bundle {  async hook() {    // You will hook into the BundleBeforePrepare event, for SecurityBundle    // and you can call the designated methods:    // .setUserPersistance(), .setSessionPersistance(), .setPermissionPersistance()    //    // You can see how `Security Mongo Bundle` does it.  }}

We do have it implemented for mongodb via MongoBundle. This is done in a separate bundle: Security Mongo Bundle.

import { MongoBundle } from "@bluelibs/mongo-bundle";import { SecurityMongoBundle } from "@bluelibs/security-mongo-bundle";
kernel.addBundles([  // order does not matter  new SecurityBundle({}),  new MongoBundle({    uri: "mongodb://localhost:27017/app",  }),
  // This bundle works together with MongoBundle  // And it creates the mongo collections "users", "permissions", and "sessions"  new SecurityMongoBundle(),]);

If you later, for example, want to move sessions over to Redis, or something faster, you can easily override the bundle. One big advantage using this is that you are never locked-in, you can always swap things, we try as much as possible to depend on abstractions rather than implementations, but at the same time want to make it plug-in to just start playing with this.

// This says, I'm not going to modify the "sessions" collection, I will not attach it to a MongoDB collection// Allowing you to customise it on your own.new SecurityMongoBundle({  sessionsCollection: null;})

And then you inject on the SecurityBundle, setSessionPersistance() your own adapter which implements ISessionPersistance.

Users

The basic, stripped-down user interface looks something like this:

export type UserId = number | string | ObjectId;
export interface IUser {  _id?: UserId;  // Is the user allowed to authenticate  isEnabled: boolean;
  createdAt: Date;  lastLoginAt?: Date;  roles?: string[];}

Since we are database agnostic, we currently allow the UserId to be string, number or ObjectId for MongoDB. Let's say we want the IUser to have a name: string as well. The recommended strategy is to extend the interface:

defs.ts
// Make sure this file gets importedimport "@bluelibs/security-bundle";
declare module "@bluelibs/security-bundle" {  export interface IUser {    name: string;  }}

Now we have added an extra variable to the user.

const securityService = container.get(SecurityService);
const userId = await securityService.createUser({  name: "Dámaso Alonso",});// Btw, this method also emits the UserAfterCreateEvent, so you can hook into it.
await securityService.updateUser(userId, {  name: "Luis de Góngora",});
await securityService.deleteUser(userId);
// Simple role handling (more in Permissioning section)await securityService.setRoles(userId, ["ADMIN"]);await securityService.getRoles(userId);

Authentication

Sessions

We need a way to identify users on all requests. For this we create a session token for each, which we verify with our session persistance layer.

This is how the session looks like:

// And session looks something like this, you can easily get the userexport interface ISession {  token: string;  userId: UserId; // string, number, ObjectId  expiresAt: Date;  data?: ISessionData; // additional metadata to store with the session. (extend the interface to add to it)}

Let's say you want to clean-up sessions for the users, we offer two simple methods for this:

// If you choose to suspend the user, you can also cancel all his active sessions:
const { sessionPersistanceLayer } = securityService;await sessionPersistanceLayer.deleteAllSessionsForUser(userId);
// This is done automatically in a cronjob by the bundle. However you can opt-out of it by using `session:{ cleanup: false }` at `SecurityBundle` config levelawait sessionPersistanceLayer.cleanExpiredTokens();

Login, Logout

Let's have some fun and explore the login-logout system:

const sessionToken = await securityService.login(userId, {  expiresIn: "14d", // zeit/ms kind  data: {    // Other data you would like to store in the session, in a key-value pair  },});
// Now that we have the token, we can fetch the session// Note that this isn't a simple fetch it can throw `SessionExpiredException` or `UserDisabledException`const session = await securityService.getSession(sessionToken);// If you want to fetch it without verification/validation, access the `sessionPersistanceLayer` property of SecurityService
// To logout use this simple method:await securityService.logout(sessionToken);

As we've seen so far it's quite easy to create users, create sessions for them that we an identify

Strategies

How can we authenticate users from an end-to-end perspective? We have passwords, biometric data, github, google. There are many ways. Let's see how the SecurityService comes in our aid.

We introduce a new concept called AuthenticationStrategy, we are going to refer to it as UAS. What this means is that it allows you to work with the UserPermissionPersistance layer to store information associated to authenticating users. For example, when dealing with password authentication, we'll store a hash of that password. If we're dealing with facebook authentication, we'll store the facebookProfileId in the User somehow.

import { SecurityService } from "@bluelibs/security-bundle";
const securityService = this.container.get(SecurityService);
// This creates or updates the "password" auth strategy UASawait securityService.updateAuthenticationStrategyData(userId, "password", {  username: "salvador@da.li"  passwordHash: "######",})
// The response of find will contain { userId, strategy: { username, passwordHash } }const response = await securityService.findThroughAuthenticationStrategy("password", {  // The filters we allow here are only "flat"-listed and equality  username: "salvador@da.li",});response.userId; // the userIdresponse.strategy; // { username: "salvador@da.li", password: }

const response = await securityService.setAuthenticationStrategyData(userId, "password");// Clear all data regarding this.await securityService.removeAuthenticationStrategyData(userId, "password");
note

These strategies work perfectly well with any authentication mechanism, we have full support for passport, opening ourselves up to 500+ authentication strategies, which can make our life a breeze!

Permissioning

Let us introduce you to our little friends: IPermission and PermissionService:

// This is how permission look like:export interface IPermission {  userId: any;  permission: string; // "ADMIN"  domain: string; // A part of the app, or an entity "INVOICES"  domainIdentifier?: string; // Typically a sub-part of the domain, maybe an `_id` or something else.}
note

Each permission has a required domain, which you have to specify, by default we recommend you use the string "app", or the less-friendly-looking PERMISSION_DEFAULT_DOMAIN export from the @bluelibs/security-bundle package.

Adding and Removing

A permission in which the domain is PERMISSION_DEFAULT_DOMAIN is regarded as a role. When you read about user roles, they are just permissions on the app domain.

import { PermissionService } from "@bluelibs/security-bundle";
const permissionService = container.get(PermissionService);
// I give "ADMIN" rights on "app" domain to userIdawait permissionService.add({  userId,  permission: "ADMIN",  domain: "app",});
await permissionService.remove({  userId,  permission: "ADMIN",  domain: "app",});

Searching

PermissionSearchFilter is an interface which is like IPermission but everything is arrayify-able and optional:

export interface IPermissionSearchFilter {  userId?: UserId | UserId[];  permission?: string | string[];  domain?: string | string[];  domainIdentifier?: string | string[];}

This type of search can aid us find permissions, verify if the user has them:

permissionService.has(permissionSearchFilter); // Promise<boolean>permissionService.findPermissions(permissionSearchFilter); // Promise<IPermission[]>;permissionService.findPermission(permissionSearchFilter); // Promise<IPermission[]>;permissionService.findDomains(userId: UserId): Promise<string[]>;
note

Keep in mind that when you specify an array, you are specifying an or condition. The userId, permission, domain and domainIdentifier have an and condition to them. Giving you a lot of flexibility when it comes to advanced permissioning.

Therefore, let's say if we want to verify if the employee has MANAGER permission on module INVOICES in your application:

await permissionService.has({  userId: employeeId,  domain: `INVOICES`,  permission: `MANAGER`,});

Hierarchy

Let us secure a method: viewSallary() is only accessible by people with role MANAGER and ADMIN. How does the check look like?

if (hasRole("ADMIN") || hasRole("MANAGER")) {  // do your thang}

What if this is not scalable, and these conditions grow? You can most likely say that if there's something a MANAGER can do, definitely an ADMIN can do too. This would mean that ADMIN will have MANAGER under its hierarchy:

// Ensure that all are uniqueconst Permissions = {  ADMIN: "ADMIN",  MANAGER: "MANAGER",};
// You can also use enum, ensure that you use strings as values// As your application will grow and you really don't want that hassleenum Permissions {  ADMIN = "ADMIN",}
// leaves are marked as 1, valueconst permissionTree = {  [Permissions.ADMIN]: {    [Permissions.MANAGER]: 1,  },};

Now all you have to do is store it in your SecurityBundle:

new SecurityBundle({  permissionTree,});

Now we have super powers, because, when we check has() if the user has only the ADMIN role, it will still return true for MANAGER role check:

await permissionService.has({  adminUserId,  permission: "MANAGER",  domain: "app",}); // true, because he's higher in the hierarchy

Let's go a little bit deeper. This can work on custom domains as well:

enum PermissionDomains {  APP = "app",  SALES = "sales",}
const tree = {  [Permissions.INVOICE_ADMIN]: {    [Permissions.INVOICE_LIST]: 1,    [Permissions.INVOICE_CREATE]: 1,  },};
// We run this check before we allow an invoice to be createdawait permissionService.add({  userId: invoiceAdminUserId,  permission: "INVOICE_ADMIN",  domain: PermissionDomains.APP,});
await permissionService.has({  invoiceAdminUserId,  permission: "INVOICE_CREATE",  domain: PermissionDomains.SALES,}); // This will be false. Look at the: `domain`
note

Careful when performing checks or adding permissions to "domain". Domains are not transferable. If you are only working with "app" domain, it's best to use roles strategy.

Domains

The domains help us give rights differently to different sections of the app:

  • ADMIN role on ProjectManagement section of your app.
  • MODERATOR role on BlogPost section of your app

In the same breath you can also create a role with app domain, called PROJECT_MANAGEMENT_ADMIN.

Another level of abstraction that we are going to introduce is the domainIdentifier, which can help us give rights to certain objects in your database:

  • ADMIN role on Post domain with postId as the domainIdentifier.
const tree = {  admin: {    viewer: 1,  },};
// We now add some roles ("admin" on "finance")await permissionService.add({  userId,  permission: "admin",  domain: "finance",});
// "viewer" on "marketing"await permissionService.add({  userId,  permission: "viewer",  domain: "marketing",});
// **true** because he is "admin" on "finance" and "viewer" is under "admin"'s hierarchyawait permissionService.has({  userId,  permission: "viewer",  domain: "finance",});
// **false** because he is only "viewer" on "marketing"await permissionService.has({  userId,  permission: "admin",  domain: "marketing",});

And for the domain identifier the logic is very similar. Let's say we have "Groups":

await permissionService.add({  userId,  permission: "viewer",  domain: "groups",  domainIdentifier: groupId, // ensure .toString() it if it's an ObjectId});
// **true**await permissionService.has({  userId,  permission: "viewer",  domain: "groups",  domainIdentifier: groupId,});
// **false**, your permission is domainIdentifier boundawait permissionService.has({  userId,  permission: "viewer",  domain: "groups",});
note

Here's a catch. When dealing with domain identifiers, having a permission on the top domain without a domain identifier, means that you have those permissions over every other identifier:

await permissionService.add({ userId, permission: "view", domain: "invoices" });await permissionService.has({  userId,  permission: "view",  domain: "invoices",  domainIdentifier: "INVOICE-0001",}); // This will be true.

This allows you to have very verbose an explicit permissioning rules: Someone wants to download invoice as pdf? We check the permission on that invoice. You happen to be someone with "view" on all invoices? Perfect I will allow you.

You may want to see all users who are viewers of Domain.Groups with that specific groupId:

permissionService.findPermissions({  domain: "app",  // optional  domainIdentifier: groupId,});

Roles

We call "role" a permission which is on app domain and has no domainIdentifier. The roles are typically stored under an array of strings under user: { roles: [] } but it can also be stored under permission collection as they normally are. It's your choice, the system works with both options, but for consistency it's best to just stick to one that fits best.

import { SecurityService } from "@bluelibs/security-bundle";
const securityService = container.get(SecurityService);const roles = await securityService.getRoles(userId);await securityService.setRoles(userId, ["ROLE1", "ROLE2"]);

Roles works with hierarchy seamlessly. To check if the user has a role and also be hierarchy aware:

const permissionService = container.get(PermissionService);
// Because the domain is "app", and no identifier. This will also check under `user.roles` to see if matchesconst hasRole = permissionService.hasRole(userId, "ROLE1"); // works with array of strings too
// ^ Is a placeholder for the below code:const hasRole = permissionService.has({  userId,  permission: "ROLE1",  domain: "app",});

The IUser interface has by default a roles: string[] property. And these roles are regarded as permissions on the PERMISSION_DEFAULT_DOMAIN.

const userId = await securityService.createUser({  roles: ["ADMIN"],});
await permissionService.hasRole(userId, "ADMIN");
warning

We decided to use roles at User level because there was a plethora of applications which have simple permissioning system. Roles can be used as employee roles: HR Manager, Developer, etc or as permissioning sets SALARIES_VIEW, etc.

If you want a scalable system we recommend you separate the "actor role" in the application and use permissioning sets(SALARIES_VIEW, USERS_ADD), later down the road you can group these and benefit of Permissioning Hierarchy.

The strategy mentioned above means that you will not interact with permissionService to mutate data (it's just an array of strings at User level). If you choose to work with permissionService (to add or remove) ensure that all your role management is done through it, because when we perform the has() role verification, we also take into consideration user.roles to apply to our dataset.

This means that if you want to switch and will be dealing with roles manipulation through add(), remove() inside PermissionService, ensure that user.roles is an empty array and don't touch it again, because Permissions is in its own persistance layer. We offered roles at User level to offer a simple, scalable and powerful way to deal with permissions, but at the same time offer the possibility to trully scale your permissioning system without hassles.

Events

You can hook into multiple type of events, you can find them by exploring the API or just looking into events.ts file.

Their names should be intuitive enough and you can import them directly from "@bluelibs/security-bundle" package:

  • UserBeforeCreateEvent
  • UserAfterCreateEvent
  • UserBeforeUpdateEvent
  • UserAfterUpdateEvent
  • UserBeforeDeleteEvent
  • UserAfterDeleteEvent
  • UserBeforeLoginEvent
  • UserAfterLoginEvent
  • UserBeforeLogoutEvent
  • UserAfterLogoutEvent
  • UserDisabledEvent
  • UserEnabledEvent
  • UserBeforeAddPermissionEvent
  • UserAfterAddPermissionEvent
  • UserBeforeRemovePermissionEvent
  • UserAfterRemovePermissionEvent
  • SessionRetrievedEvent
  • SessionBeforeCreateEvent
  • SessionAfterCreateEvent

Meta

Summary

There we have it. A powerful security module with lots of goodies, flexible to the bone, event-driven and ready to be used as the guardian of your application.

Boilerplates

Challenges

  1. Try to implement a password authentication strategy. (1p)
  2. What is a role? What is a domain? What is a domain identifier? (1p)
  3. If I have a permission on a domain, would I have the same permission on every domainIdentifier from that domain? (2p)
  4. Can I have users stored in MongoDB, sessions stored on Redis and Permissions in Neo4J? (1p)
  5. What happens with expired sessions? (2p)
  6. What are the benefits of having session-based authentication? (1p)
  7. When should we stop storing roles under User ? (4p)