EJB Security

CSCI 5931 Web Security Kartikeya Kakarala

Young Ho Choung

Contents

– Introduction– Traditional Client/Server Architecture– Multi-tier Architecture– EJB Architecture & its Roles– EJB Security model– Method Permissions– Programmatic Security– Conclusions– References

Enterprise Java Beans Introduction

• Enterprise Java Beans (EJB) is a standard server side component model

• The EJB architecture logically extends the Java Beans component model to support server components

• An EJB is a non-visual Java Bean that runs on a server

• An EJB is – A collection of Java classes

– An XML file

– Bundled into a single unit

– The Java classes must follow certain rules

– The Java classes must provide callback methods

Introduction(cont..)

• In a traditional client/server application, the client application contains:– presentation logic(windows and control manipulation)

– business logic(algorithms and business rules)

– data manipulation logic(database connections and SQL Queries)

Traditional Client/Server Architecture

Multi-tier Architecture

• Client applications contain only presentation logic – a thin client

• Business logic and data access logic are partitioned into separate components and deployed onto one or more servers

• EJB Architecture is gaining broad acceptance due to it’s high value benefits that address directly the needs of today's diverse server development community like – Scalability

– Simplicity

– Ease of development

– Security

– Interoperability

– Component based computing

– Application Containers

EJB Architecture

EJB Architecture Roles

• Various EJB Architecture roles handle EJB development and deployment. They are:-– Bean Provider

– Application Assembler

– Deployer

– EJB Service Provider

– EJB Container Provider

– System Administrator

Bean Provider

• The Bean Provider– Writes the individual Enterprise Java Beans.

– Can be a Business entity or system encapsulated as entity or session beans.

– Creates deployment descriptor.

Application Assembler

• An Application Assembler – Creates a full application from individual beans

– May also create JSP’s and servlets that utilize those beans.

– Edits the Deployment Descriptors to fit the application.

Deployer

• A Deployer– Deploys the application into a running EJB Server.

– Sets up interaction between architecture as envisioned by the assembler and actual environment in which it runs.

EJB Service Provider & EJB Container Provider

• The EJB Service Provider & EJB Container Provider Work together to write the EJB Server.– Figure displaying the EJB model

System Administrator

• The System Administrator – Takes care of the computer systems that run the EJB

Server and related services.

– Administrates Operating systems and network related to the server.

EJB Security model

• EJB 1.1 security model is– Role based, and helps to restrict access to beans and

their methods based on a client’s role.

– It provides an easy way to control who can call which beans and methods and automatically establishes the identity of the caller.

– Example of defining roles is an online banking application pg 239,240

Examples of Security Goals

– A customer can access only her own account

– A trader can only execute transactions that have a value less than one million Swiss francs

– A tax inspector is prohibited from modifying her own tax liability data

– An underage subscriber does not have access to an X-rated online movie

Method Permissions• Access to the beans and their methods can be made

limited based on their roles.• For this each role must be listed in the deployment

descriptor.• Method permissions are defined using method

permission elements.• Each method permission element contains a role-

name element and one or more EJBs and their methods,as defined by ejb-name and method-name elements.Sample of the method pg 240-241.

Programmatic Security

• Normally Application Assembler and the Deployer configure security in a EJB server.

• Programmatically sometimes bean provider has to access some security information,for which EJB provides 2 methods – Principal getCallerPrincipal()

– Boolean isCallerInRole(String roleName)

First Method

• getCallerPrincipal()– It returns a Principal object corresponding to the

identity of the caller.

– It allows the use of the identity of the caller inside the code of the bean.

– Example :-If we want a customer to view their own balance but nobody else’s.We could do that by calling the principal of the caller and use that to fetch their account.

– pg 242.

Second Method

• isCallerInRole()– Boolean function returning true if the caller is in the

role or returns false

– Used usually when simple permissions are not enough.

– Example:- if we have a situation where we need to give permission to bankers to only add up to 1000$ to an account at a time and admin be given all rights.This can be done as Pg 243

Security-role-ref Element

• The Security-role-ref element– It alerts the Application assembler and the Deployer if

a particular role has dependency in a bean.– < Security-role-ref >

<description>This security role will have no limit on

the size of transaction </description><role-name>admin</role-name>< /Security-role-ref >

– Pg 243

Conclusions

• EJB Security focus on minimal programmatic and declarative access control mechanisms.

• This mechanism provides role-based access control for EJB.

• Access restriction can be successfully obtained using EJB Security model.

References

• Garms, Jess and Daniel Somerfield. Professional Java Security. Wrox. 2001. (ISBN: 1861004257)

• Article on EJB Security by Paul Perrone, http://www.informit.com

• www.ibm.com/research/security

• www.javaworld.com/javaworld/jw-02-2002/ jw-0215-ejbsecurity.html

• www.java.sun.com/ejbsecurity