|By Guosheng Huang||
|September 1, 2003 12:00 AM EDT||
With the upcoming release of J2SE 1.5, which includes a lot of enhancements to cryptography, XML security, Public Key Infrastructure (PKI), Kerberos, and the federating identity, the JAAS will play a more important role in J2EE security implementations.
Overview of JAAS
Authentication is the process of verifying that a user has the right to use identities established by the enterprise user registry. The authentication mechanism of JAAS is built on a set of pluggable modules (see Figure 1). JAAS allows different authentication models to be plugged in at runtime. The client applications always interact with JAAS through the LoginContext object.
The authentication process typically involves the following steps:
- Create a LoginContext object. The LoginContext looks up the configuration file to determine which LoginModule to use. Also, optionally, you can pass a CallbackHandler to the LoginContext.
- Perform authentication by calling the login method of LoginContext, which loads the predefined LoginModule to check if the user can be authenticated.
- Associate principals and credentials with the Subject if the user is authenticated.
- Or throw a LoginException in case login failed.
- Use the logout method of LoginContext to log out.
A Subject in JAAS represents an authenticated entity, such as a person or device. It contains a set of principals and security-related attributes such as a password and cryptographic keys. In the JAAS architecture, the Subject, along with the Permission, plays an important role in the authorization process.
Of all the authentication modules, the LoginModule is the interface to a particular authentication mechanism. Although the LoginModule never gets called directly by the client application, it provides a particular type of authentication via a pluggable module, which implements the authentication algorithm and determines how the actual authentication is performed. Sun provides a few default LoginModule implementations, such as JndiLoginModule, Krb2LoginModule, UnixLoginModule, and NTLoginModule under the package of sun.com.security.auth .module. Since the JAAS login architecture is extensible, you can pretty much "plug in" any LoginModule just by specifying which LoginModule to use in the configuration file. An example of a configuration file looks like this:
com.sample.module.MyLoginModule required debug=true;
Here MySample is the name of the login context, which is passed into the LoginContext constructor when you create a new LoginContext to start the authentication process, followed by the configuration block. The block informs JAAS about the loginModule that should be used to perform authentication during the login. In addition to the LoginModule, any options to that LoginModule can also be specified here.
During the login step, the CallbackHandler is used by LoginModule to communicate with the user to obtain authentication information. The CallbackHandler handles three types of Callbacks: NameCallback, which prompts the user for a user name; PasswordCallback, which prompts for a password; and TextOutputCallback, which reports any error, warning, or other messages sent to the user.
Authorization is the process of determining whether an authenticated user is permitted to perform some actions, such as accessing a resource. The process is policy-based since JAAS is built on the existing Java security model. The policy configuration file essentially contains a list of entries, such as "keystore" and/or "grant". The grant entry includes all the permissions granted for the authenticated codes or principals to do the security-sensitive operations, for instance, accessing a particular Web page or local file. JAAS supports principal-based policy entry. Permissions can be granted in the policy to specific principals.
The basic format of a grant entry looks like this:
grant Codebase "codebase_URL" Signedby "signer_name,"The "action" may be required or can be omitted depending on the permission type.
Principal principal_class_name "principal_name",
Principal principal_class_name "principal_name",
permission permission_class_name "target_name", "action",
permission permission_class_name "target_name", "action",
In the JAAS architecture, the Policy object represents the system security policy for a Java application environment and there's only one Policy object in effect at any time according to the Java 2 SDK document. The default implementation of Policy is sun.security.provider.PolicyFile, in which the policies are specified within one or more policy configuration files.
Once the user is authenticated, the authorization takes place via the Subject.doAs method, or the static doAsPrivileged method from Subject class. The doAs method dynamically associates the subject with the current AccessControlContext and then invokes the run method to execute the action, which causes the security checks. The permission check process goes through the following steps illustrated in Figure 2:
- Invoke Subject.doAs (or doAsPrivileged).
- Call SecurityManager.checkPermission or other check methods to check the permission.
- The SecurityManager delegates the check to the AccessController.
- The AccessController ensures the relevant AccessControlContext contains sufficient permissions for the action to be taken.
- The SecurityManager updates the current AccessControlContext with the permissions granted to the subject via the Policy from the policy file.
Like the LoginModule, the Policy is also a pluggable module. You can hook up other Policy implementations by changing "policy.provider=sun.security.provider.PolicyFile" in the java.security properties file to a value of the Policy class you want to use.
JAAS is built on top of the existing Java security model, which is CodeSource-based, and the plaintext format policy file implementation. This may not be enough for the enterprise application. You may want to use custom security repositories with JAAS, such as LDAP (lightweight directory access protocol), database, or another file system. It can be done by writing your own customized modules, thanks to the JAAS pluggable feature. However, this would require a good understanding of the modules and processes involved in JAAS, and you need to do a lot of coding to override the proper classes and take care of both the configure and policy files.
Ideally, we'd like to able to extend JAAS in an easier way so whenever a custom security repository or different access control mechanism changed or needed to add, you could just develop and plug in the different small modules (namely, the adapters) to accommodate these new changes or requirements, and best of all, without having to understand or know the details of the JAAS process. Also, we would like to be able to make this change simply by changing a configuration file. Another goal is that our JAAS extension component could be used in different J2EE applications - stand-alone or Web. Figure 3 outlines the design of our JAAS extension component.
Our JAAS extension component takes advantage of the JAAS pluggable architecture by implementing our customized LoginModule and Policy modules. In these modules, we delegate the data requests to the adapters. Each of these adapters is isolated to simple tasks such as data retrieval, so you can rapidly develop different adapters for different security repositories or algorithms instead of trying to implement different LoginModule or Policy modules, which are far more complex and require more effort.
You can download the complete source code from www.sys-con.com/java/sourcec.cfm".
The AuthLoginModule class is our customized LoginModule implementation. The LoginModule is a pluggable component in the JAAS authentication process and serves two purposes:
- Authenticate the user.
- Update the Subject with relevant principals and credentials if authentication succeeded.
- Obtains the user name and password. Typically, the LoginModule invokes the handle method of the CallbackHandler to get the user name and password.
- Verifies the password against the one in the data source.
Once it has the user name and password at hand, the AuthLoginModule, our customized implementation of LoginModule, instantiates the LoginSourceAdapter via the LoginSourceAdapterFactory and delegates the actual authentication to the source adapter. The adapter is nothing more than a simple class, which pulls down the user information from a particular data source, such as database or LDAP, or some other system.
String userName = request.getParameter ("user");
String password = request.getParameter("password");
LoginContext context = new LoginContext ("MySample",
new AuthCallbackHandler (userName, password));
In the "commit" phase, the AuthloginModule retrieves the relevant information from the LoginSourceAdapter and associates them with the Subject.
The LoginSourceAdapter is an interface of source adapter for the authentication. It has four methods for required implementations:
- void initialize (Hashtable parameters): The initialize method is called to initialize the adapter with the relevant parameters. The method is called immediately after object creation and prior to any calls to other methods.
- boolean authenticate (String userName, char password): The authenticate method is called to authenticate the user.
- String getGroupNames (String userName): The getGroupNames method is called to get the relevant principal information after authentication succeeded.
- void terminate (): This method is called when the logout method of LoginModule is invoked. It gives the adapter a chance to do some clean-up work.
The argument for the initialize method is the collection of a key-value pair. It could be the parameters for database connectivity, such as driver, URL, user ID, and password, or other information required for your adapter. You can specify these parameters in the configuration file, which I'll discuss later.
Under the JAAS architecture, the security policy is handled by the java.security.Policy class, which establishes the various Permissions granted to a particular CodeSource or Principal. As discussed in the previous section, the default implementation is sun.security.provider.PolicyFile. The PolicyFile uses the plaintext file to establish the mapping between permissions and CodeSource, which may not be good enough for the enterprise application. A centralized system such as a relational database for supporting role-base security would be better.
Obviously, to extend JAAS authorization to handle the different security schemes from different sources, we need to write our own Policy implementation.
The steps to create a customized Policy implementation are:
* Extend java.security.Policy.
* Implement getPermissions ().
* Implement refresh ().
If you look at the implementation of our customized Policy class, you may notice that our AuthPolicy class is derived from the sun.security.provider.PolicyFile instead of java.security .Policy. Why? First, I want to implement the AuthPolicy class as the generic Policy class, which can deal with the default policy file without any adapter plugged in. By deriving from the PolicyFile, we don't need to implement the policy file parsing and other related codes. Also, when the application is running with a Security- Manager enabled, a few permissions, such as doAsPrivileged AuthPermission and read FilePermission (for loading a configuration file), need to be granted in order to execute the JAAS. Sure, these permissions could be stored in the data source, but it might be convenient to put them in the standard Java security policy file. However, for serious development you should implement an adapter to deal with these issues.
Following the same design pattern in the extending authentication, our Policy class delegates the permission requests to the PermissionAdapter.
In the Permissions class, the different Permission is held in its own Permission- Collection instance. If you create a custom Permission class, you need to create your own PermissionCollection, otherwise there's no guarantee that your Permission object will be consulted.
The PermissionAdapter is the interface of the pluggable module for authorization in our JAAS extension component. It evaluates the policy from a particular data source and delivers a PermissionCollection that contains a set of permissions granted. The PermissionAdapter interface has the following methods:
- void initialize (Hashtable initParams): The initialize method is called to initialize the adapter with the relevant parameter. The method is called immediately and prior to any calls to other methods. Also, it's called when Policy's refresh is invoked.
- PermissionCollection getPermissions (ProtectionDomain domain): This method is called whenever the Permissions with particular Principals is requested.
First, in the initialize method, we'll retrieve all the permission information for all roles from the database table and populate them in the collection, e.g., Hashtable.
Next, in the getPermissions method, we'll collect the permissions that relate to the involved Principals (this is the only concern for the role-based access control) and return them. Note that we can get relevant Principals by calling the getPrincipals method of ProtectedDomain. It's so simple, isn't it?
JaasUtil is the main contact to our JAAS extension component, and it has a constructor that takes the user name and password. There are two key methods:
- boolean authenticate()
- boolean checkPermission(Subject subject, final Permission perm)
Listing 1 shows how to use JaasUtil. This code first gets the user name and password from the HttpServletRequest and tries to authenticate the user. Then it checks if this user has permission to access the "editReg.jsp".
Now we have our customized implementations of the LoginModule, Policy, and other related modules. These modules can delegate the relevant data requests to the appropriate adapters; so far so good. However, in the JAAS architecture, the LoginModule and Policy are never directly invoked by the application, so how do we know which adapter should be instantiated and how to pass the necessary parameters or information, such as connectivity, to the adapters?
The answer is that the adapters can be dynamically configured by updating an XML configuration file. This XML configuration file consists of two major sections:
You can specify which LoginSourceAdapter and
PermissionAdapter to use. It's also possible to pass additional
information to the adapter in the configuration file.
There are two ways to let JaasUtil know where to look for the
1. Specify the configuration file via the -Dcom.auth.config
When you deploy the JAAS extension component, the customized
security Policy class file must be added to Java's jre/lib directory,
which will cause the policy class file to be loaded by the bootstrap
class loader. Otherwise, it won't be picked up and the default policy
class provided by Sun will be used instead, even though you placed
the policy class file on the Java class path.
2. Call JaasUtil.setConfigFile (configFile).
Extending JAAS is not difficult. The JAAS architecture provides you with the flexibility to customize the authentication and authorization processes. Understanding how these processes work is the first step in knowing how to "roll your own" implementation. In this article, we recalled the basics of the JAAS, and examined the details of how to extend JAAS to be a more dynamic, flexible, and scalable framework. With this extended framework, you can easily create your own login and access control mechanisms to support either your own enterprise-specific security requirements or emerging security standards, or leverage your existing or customized security models as the adapters, and then "plug" them into JAAS. This should provide a standard-based and highly customized authentication and authorization for your enterprise applications.
You can specify which LoginSourceAdapter and PermissionAdapter to use. It's also possible to pass additional information to the adapter in the configuration file.
There are two ways to let JaasUtil know where to look for the configuration file:
1. Specify the configuration file via the -Dcom.auth.config
When you deploy the JAAS extension component, the customized security Policy class file must be added to Java's jre/lib directory, which will cause the policy class file to be loaded by the bootstrap class loader. Otherwise, it won't be picked up and the default policy class provided by Sun will be used instead, even though you placed the policy class file on the Java class path.
|Laurent DUTHEIL 06/07/05 10:57:55 AM EDT|
I'm very interested about your article.
|Jon Lee 02/10/05 09:30:07 PM EST|
Thank you writing this informative article.
Contrarily to Maciek Kolesnik and Greg Bishop's opinion, this article is very helpful and useful in understanding JAAS.
The usefulness of understanding JAAS further is now proven when Sun included JAAS in J2SE and J2EE.
Why does this article's helpfulness have anything to do with MS Exchange? So, does it mean only associating with MS Exchange will be helpful? I don't think so.
I think Dr. Huang has already shown that JAAS is easy to extend. So, JAAS can be intergrated with other systems by creating your customized LoginModule.
|Nitin Bhavsar 12/08/04 04:54:51 AM EST|
1. The article is interesting and nice with simple language. There are plenty of articles on JAAS but still I had many use-case related basic questions. The article helped me understand it (though not fully)...
|Thomas Nietsch 07/02/04 05:51:16 AM EDT|
Where are the figures?
|Greg Bishop 05/10/04 10:27:38 AM EDT|
This is not helpful because it does not discuss implementation in an existing security architecture and integration with existing security mechanisms like MS Exchange, etc.
If I wanted to roll my own anything, I sure wouldn''t start with somehting as common as a security architecture.
|maciek kolesnik 10/23/03 09:09:05 AM EDT|
I think it would really be worthwhile to mention challenges and opportunities that JAAS presents when implementing it in a real J2EE environment (with filters, servlets, EJBs, resource adapters, etc.). There is a talk of adapting JAAS authentication/access control mechanisms in the upcoming J2EE revisions. I'd be interesting in hearing author's opinion on this, otherwise this article probably fits more in the J2SE column :-)
|Bruce Steely 10/07/03 05:02:10 PM EDT|
Where is Listing 1?
SYS-CON Events announced today that Tintri Inc., a leading producer of VM-aware storage (VAS) for virtualization and cloud environments, will exhibit at the 18th International CloudExpo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, New York, and the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
May. 30, 2016 02:45 AM EDT Reads: 2,503
SYS-CON Events announced today that MangoApps will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. MangoApps provides modern company intranets and team collaboration software, allowing workers to stay connected and productive from anywhere in the world and from any device. For more information, please visit https://www.mangoapps.com/.
May. 30, 2016 02:45 AM EDT Reads: 1,045
SYS-CON Events announced today that Alert Logic, Inc., the leading provider of Security-as-a-Service solutions for the cloud, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Alert Logic, Inc., provides Security-as-a-Service for on-premises, cloud, and hybrid infrastructures, delivering deep security insight and continuous protection for customers at a lower cost than traditional security solutions. Ful...
May. 30, 2016 02:15 AM EDT Reads: 2,981
In his session at 18th Cloud Expo, Bruce Swann, Senior Product Marketing Manager at Adobe, will discuss how the Adobe Marketing Cloud can help marketers embrace opportunities for personalized, relevant and real-time customer engagement across offline (direct mail, point of sale, call center) and digital (email, website, SMS, mobile apps, social networks, connected objects). Bruce Swann has more than 15 years of experience working with digital marketing disciplines like web analytics, social med...
May. 30, 2016 02:00 AM EDT Reads: 1,463
SYS-CON Events announced today Object Management Group® has been named “Media Sponsor” of SYS-CON's 18th International Cloud Expo, which will take place on June 7–9, 2016, at the Javits Center in New York City, NY, and the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
May. 30, 2016 01:00 AM EDT Reads: 2,673
SYS-CON Events announced today that EastBanc Technologies will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. EastBanc Technologies has been working at the frontier of technology since 1999. Today, the firm provides full-lifecycle software development delivering flexible technology solutions that seamlessly integrate with existing systems – whether on premise or cloud. EastBanc Technologies partners with p...
May. 29, 2016 10:00 PM EDT Reads: 2,404
SYS-CON Events announced today that ContentMX, the marketing technology and services company with a singular mission to increase engagement and drive more conversations for enterprise, channel and SMB technology marketers, has been named “Sponsor & Exhibitor Lounge Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2016, at the Javits Center in New York City, New York. “CloudExpo is a great opportunity to start a conversation with new prospects, but what happens after the...
May. 29, 2016 04:45 PM EDT Reads: 1,328
WebRTC is bringing significant change to the communications landscape that will bridge the worlds of web and telephony, making the Internet the new standard for communications. Cloud9 took the road less traveled and used WebRTC to create a downloadable enterprise-grade communications platform that is changing the communication dynamic in the financial sector. In his session at @ThingsExpo, Leo Papadopoulos, CTO of Cloud9, will discuss the importance of WebRTC and how it enables companies to fo...
May. 29, 2016 04:15 PM EDT Reads: 2,603
The IoT is changing the way enterprises conduct business. In his session at @ThingsExpo, Eric Hoffman, Vice President at EastBanc Technologies, discuss how businesses can gain an edge over competitors by empowering consumers to take control through IoT. We'll cite examples such as a Washington, D.C.-based sports club that leveraged IoT and the cloud to develop a comprehensive booking system. He'll also highlight how IoT can revitalize and restore outdated business models, making them profitable...
May. 29, 2016 02:00 PM EDT Reads: 2,991
The IoTs will challenge the status quo of how IT and development organizations operate. Or will it? Certainly the fog layer of IoT requires special insights about data ontology, security and transactional integrity. But the developmental challenges are the same: People, Process and Platform. In his session at @ThingsExpo, Craig Sproule, CEO of Metavine, will demonstrate how to move beyond today's coding paradigm and share the must-have mindsets for removing complexity from the development proc...
May. 29, 2016 01:00 PM EDT Reads: 1,992
Customer experience has become a competitive differentiator for companies, and it’s imperative that brands seamlessly connect the customer journey across all platforms. With the continued explosion of IoT, join us for a look at how to build a winning digital foundation in the connected era – today and in the future. In his session at @ThingsExpo, Chris Nguyen, Group Product Marketing Manager at Adobe, will discuss how to successfully leverage mobile, rapidly deploy content, capture real-time d...
May. 29, 2016 12:45 PM EDT Reads: 1,698
What a difference a year makes. Organizations aren’t just talking about IoT possibilities, it is now baked into their core business strategy. With IoT, billions of devices generating data from different companies on different networks around the globe need to interact. From efficiency to better customer insights to completely new business models, IoT will turn traditional business models upside down. In the new customer-centric age, the key to success is delivering critical services and apps wit...
May. 29, 2016 10:30 AM EDT Reads: 1,305
Join us at Cloud Expo | @ThingsExpo 2016 – June 7-9 at the Javits Center in New York City and November 1-3 at the Santa Clara Convention Center in Santa Clara, CA – and deliver your unique message in a way that is striking and unforgettable by taking advantage of SYS-CON's unmatched high-impact, result-driven event / media packages.
May. 29, 2016 10:00 AM EDT Reads: 2,556
In his keynote at 18th Cloud Expo, Andrew Keys, Co-Founder of ConsenSys Enterprise, will provide an overview of the evolution of the Internet and the Database and the future of their combination – the Blockchain. Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life ...
May. 29, 2016 09:45 AM EDT Reads: 2,043
SYS-CON Events announced today that BMC Software has been named "Siver Sponsor" of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2015 at the Javits Center in New York, New York. BMC is a global leader in innovative software solutions that help businesses transform into digital enterprises for the ultimate competitive advantage. BMC Digital Enterprise Management is a set of innovative IT solutions designed to make digital business fast, seamless, and optimized from mainframe to mo...
May. 29, 2016 09:30 AM EDT Reads: 2,324
SYS-CON Events announced today that MobiDev will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. MobiDev is a software company that develops and delivers turn-key mobile apps, websites, web services, and complex software systems for startups and enterprises. Since 2009 it has grown from a small group of passionate engineers and business managers to a full-scale mobile software company with over 200 develope...
May. 29, 2016 08:15 AM EDT Reads: 2,781
SoftLayer operates a global cloud infrastructure platform built for Internet scale. With a global footprint of data centers and network points of presence, SoftLayer provides infrastructure as a service to leading-edge customers ranging from Web startups to global enterprises. SoftLayer's modular architecture, full-featured API, and sophisticated automation provide unparalleled performance and control. Its flexible unified platform seamlessly spans physical and virtual devices linked via a world...
May. 29, 2016 07:00 AM EDT Reads: 2,324
Companies can harness IoT and predictive analytics to sustain business continuity; predict and manage site performance during emergencies; minimize expensive reactive maintenance; and forecast equipment and maintenance budgets and expenditures. Providing cost-effective, uninterrupted service is challenging, particularly for organizations with geographically dispersed operations.
May. 29, 2016 06:00 AM EDT Reads: 2,188
As cloud and storage projections continue to rise, the number of organizations moving to the cloud is escalating and it is clear cloud storage is here to stay. However, is it secure? Data is the lifeblood for government entities, countries, cloud service providers and enterprises alike and losing or exposing that data can have disastrous results. There are new concepts for data storage on the horizon that will deliver secure solutions for storing and moving sensitive data around the world. ...
May. 29, 2016 06:00 AM EDT Reads: 1,378
SYS-CON Events announced today TechTarget has been named “Media Sponsor” of SYS-CON's 18th International Cloud Expo, which will take place on June 7–9, 2016, at the Javits Center in New York City, NY, and the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. TechTarget is the Web’s leading destination for serious technology buyers researching and making enterprise technology decisions. Its extensive global networ...
May. 29, 2016 05:15 AM EDT Reads: 3,282