|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?
Pulzze Systems was happy to participate in such a premier event and thankful to be receiving the winning investment and global network support from G-Startup Worldwide. It is an exciting time for Pulzze to showcase the effectiveness of innovative technologies and enable them to make the world smarter and better. The reputable contest is held to identify promising startups around the globe that are assured to change the world through their innovative products and disruptive technologies. There w...
Aug. 27, 2016 07:45 AM EDT Reads: 646
DevOps at Cloud Expo, taking place Nov 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 19th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long dev...
Aug. 27, 2016 06:15 AM EDT Reads: 2,333
Today we can collect lots and lots of performance data. We build beautiful dashboards and even have fancy query languages to access and transform the data. Still performance data is a secret language only a couple of people understand. The more business becomes digital the more stakeholders are interested in this data including how it relates to business. Some of these people have never used a monitoring tool before. They have a question on their mind like “How is my application doing” but no id...
Aug. 27, 2016 03:15 AM EDT Reads: 1,766
Personalization has long been the holy grail of marketing. Simply stated, communicate the most relevant offer to the right person and you will increase sales. To achieve this, you must understand the individual. Consequently, digital marketers developed many ways to gather and leverage customer information to deliver targeted experiences. In his session at @ThingsExpo, Lou Casal, Founder and Principal Consultant at Practicala, discussed how the Internet of Things (IoT) has accelerated our abil...
Aug. 27, 2016 02:30 AM EDT Reads: 2,001
With so much going on in this space you could be forgiven for thinking you were always working with yesterday’s technologies. So much change, so quickly. What do you do if you have to build a solution from the ground up that is expected to live in the field for at least 5-10 years? This is the challenge we faced when we looked to refresh our existing 10-year-old custom hardware stack to measure the fullness of trash cans and compactors.
Aug. 27, 2016 01:45 AM EDT Reads: 1,731
The emerging Internet of Everything creates tremendous new opportunities for customer engagement and business model innovation. However, enterprises must overcome a number of critical challenges to bring these new solutions to market. In his session at @ThingsExpo, Michael Martin, CTO/CIO at nfrastructure, outlined these key challenges and recommended approaches for overcoming them to achieve speed and agility in the design, development and implementation of Internet of Everything solutions wi...
Aug. 27, 2016 01:15 AM EDT Reads: 2,014
Cloud computing is being adopted in one form or another by 94% of enterprises today. Tens of billions of new devices are being connected to The Internet of Things. And Big Data is driving this bus. An exponential increase is expected in the amount of information being processed, managed, analyzed, and acted upon by enterprise IT. This amazing is not part of some distant future - it is happening today. One report shows a 650% increase in enterprise data by 2020. Other estimates are even higher....
Aug. 27, 2016 12:45 AM EDT Reads: 2,936
SYS-CON Events announced today that 910Telecom will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Housed in the classic Denver Gas & Electric Building, 910 15th St., 910Telecom is a carrier-neutral telecom hotel located in the heart of Denver. Adjacent to CenturyLink, AT&T, and Denver Main, 910Telecom offers connectivity to all major carriers, Internet service providers, Internet backbones and ...
Aug. 26, 2016 10:00 PM EDT Reads: 1,859
SYS-CON Events announced today Telecom Reseller has been named “Media Sponsor” of SYS-CON's 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Telecom Reseller reports on Unified Communications, UCaaS, BPaaS for enterprise and SMBs. They report extensively on both customer premises based solutions such as IP-PBX as well as cloud based and hosted platforms.
Aug. 26, 2016 07:00 PM EDT Reads: 684
Smart Cities are here to stay, but for their promise to be delivered, the data they produce must not be put in new siloes. In his session at @ThingsExpo, Mathias Herberts, Co-founder and CTO of Cityzen Data, will deep dive into best practices that will ensure a successful smart city journey.
Aug. 26, 2016 04:45 PM EDT Reads: 1,549
The 19th International Cloud Expo has announced that its Call for Papers is open. Cloud Expo, to be held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, Big Data, Internet of Things, DevOps, Digital Transformation, Microservices and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding business opportuni...
Aug. 26, 2016 04:00 PM EDT Reads: 3,951
There is growing need for data-driven applications and the need for digital platforms to build these apps. In his session at 19th Cloud Expo, Muddu Sudhakar, VP and GM of Security & IoT at Splunk, will cover different PaaS solutions and Big Data platforms that are available to build applications. In addition, AI and machine learning are creating new requirements that developers need in the building of next-gen apps. The next-generation digital platforms have some of the past platform needs a...
Aug. 26, 2016 03:15 PM EDT Reads: 501
Internet of @ThingsExpo, taking place November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 19th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The Internet of Things (IoT) is the most profound change in personal and enterprise IT since the creation of the Worldwide Web more than 20 years ago. All major researchers estimate there will be tens of billions devices - comp...
Aug. 26, 2016 10:15 AM EDT Reads: 3,598
Data is the fuel that drives the machine learning algorithmic engines and ultimately provides the business value. In his session at Cloud Expo, Ed Featherston, a director and senior enterprise architect at Collaborative Consulting, will discuss the key considerations around quality, volume, timeliness, and pedigree that must be dealt with in order to properly fuel that engine.
Aug. 26, 2016 09:45 AM EDT Reads: 1,872
19th Cloud Expo, taking place November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy. Meanwhile, 94% of enterpri...
Aug. 26, 2016 05:00 AM EDT Reads: 3,063
I wanted to gather all of my Internet of Things (IOT) blogs into a single blog (that I could later use with my University of San Francisco (USF) Big Data “MBA” course). However as I started to pull these blogs together, I realized that my IOT discussion lacked a vision; it lacked an end point towards which an organization could drive their IOT envisioning, proof of value, app dev, data engineering and data science efforts. And I think that the IOT end point is really quite simple…
Aug. 25, 2016 11:45 PM EDT Reads: 2,323
Identity is in everything and customers are looking to their providers to ensure the security of their identities, transactions and data. With the increased reliance on cloud-based services, service providers must build security and trust into their offerings, adding value to customers and improving the user experience. Making identity, security and privacy easy for customers provides a unique advantage over the competition.
Aug. 25, 2016 09:15 PM EDT Reads: 2,247
Is the ongoing quest for agility in the data center forcing you to evaluate how to be a part of infrastructure automation efforts? As organizations evolve toward bimodal IT operations, they are embracing new service delivery models and leveraging virtualization to increase infrastructure agility. Therefore, the network must evolve in parallel to become equally agile. Read this essential piece of Gartner research for recommendations on achieving greater agility.
Aug. 25, 2016 05:15 PM EDT Reads: 795
SYS-CON Events announced today that Venafi, the Immune System for the Internet™ and the leading provider of Next Generation Trust Protection, will exhibit at @DevOpsSummit at 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Venafi is the Immune System for the Internet™ that protects the foundation of all cybersecurity – cryptographic keys and digital certificates – so they can’t be misused by bad guys in attacks...
Aug. 25, 2016 01:00 PM EDT Reads: 2,640
For basic one-to-one voice or video calling solutions, WebRTC has proven to be a very powerful technology. Although WebRTC’s core functionality is to provide secure, real-time p2p media streaming, leveraging native platform features and server-side components brings up new communication capabilities for web and native mobile applications, allowing for advanced multi-user use cases such as video broadcasting, conferencing, and media recording.
Aug. 25, 2016 08:45 AM EDT Reads: 2,166