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EJB Security
CSCI 5931 Web Security
Kartikeya Kakarala
Young Ho Choung
Contents
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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
Introduction(cont..)
• An EJB is
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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
Traditional Client/Server
Architecture
• 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)
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
• 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
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Scalability
Simplicity
Ease of development
Security
Interoperability
Component based computing
Application Containers
EJB Architecture Roles
• Various EJB Architecture roles handle EJB
development and deployment. They are:–
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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 Xrated 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 rolename 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-0215ejbsecurity.html
• www.java.sun.com/ejbsecurity