What Are Realms, Users, Groups, and Roles?

A realm is a security policy domain defined for a web or application server. A realm contains a collection of users, who may or may not be assigned to a group. Managing users on the GlassFish Server is discussed in Managing Users and Groups on the GlassFish Server.

An application will often prompt for a user name and password before allowing access to a protected resource. After the user name and password have been entered, that information is passed to the server, which either authenticates the user and sends the protected resource or does not authenticate the user, in which case access to the protected resource is denied. This type of user authentication is discussed in Specifying an Authentication Mechanism in the Deployment Descriptor.

In some applications, authorized users are assigned to roles. In this situation, the role assigned to the user in the application must be mapped to a principal or group defined on the application server. Figure 24–6 shows this. More information on mapping roles to users and groups can be found in Setting Up Security Roles.

The following sections provide more information on realms, users, groups, and roles.

Figure 24–6 Mapping Roles to Users and Groups

What Is a Realm?

A realm is a security policy domain defined for a web or application server. The protected resources on a server can be partitioned into a set of protection spaces, each with its own authentication scheme and/or authorization database containing a collection of users and groups. For a web application, a realm is a complete database of users and groups identified as valid users of a web application or a set of web applications and controlled by the same authentication policy.

The Java EE server authentication service can govern users in multiple realms. The file, admin-realm, and certificate realms come preconfigured for the GlassFish Server.

In the file realm, the server stores user credentials locally in a file named keyfile. You can use the Administration Console to manage users in the file realm. When using the file realm, the server authentication service verifies user identity by checking the file realm. This realm is used for the authentication of all clients except for web browser clients that use HTTPS and certificates.

In the certificate realm, the server stores user credentials in a certificate database. When using the certificate realm, the server uses certificates with HTTPS to authenticate web clients. To verify the identity of a user in the certificate realm, the authentication service verifies an X.509 certificate. For step-by-step instructions for creating this type of certificate, see Working with Digital Certificates. The common name field of the X.509 certificate is used as the principal name.

The admin-realm is also a file realm and stores administrator user credentials locally in a file named admin-keyfile. You can use the Administration Console to manage users in this realm in the same way you manage users in the file realm. For more information, see Managing Users and Groups on the GlassFish Server.

What Is a User?

A user is an individual or application program identity that has been defined in the GlassFish Server. In a web application, a user can have associated with that identify a set of roles that entitle the user to access all resources protected by those roles. Users can be associated with a group.

A Java EE user is similar to an operating system user. Typically, both types of users represent people. However, these two types of users are not the same. The Java EE server authentication service has no knowledge of the user name and password you provide when you log in to the operating system. The Java EE server authentication service is not connected to the security mechanism of the operating system. The two security services manage users that belong to different realms.

What Is a Group?

A group is a set of authenticated users, classified by common traits, defined in the GlassFish Server. A Java EE user of the file realm can belong to a group on the GlassFish Server. (A user in the certificate realm cannot.) A group on the GlassFish Server is a category of users classified by common traits, such as job title or customer profile. For example, most customers of an e-commerce application might belong to the CUSTOMER group, but the big spenders would belong to the PREFERRED group. Categorizing users into groups makes it easier to control the access of large numbers of users.

A group on the GlassFish Server has a different scope from a role. A group is designated for the entire GlassFish Server, whereas a role is associated only with a specific application in the GlassFish Server.

What Is a Role?

A role is an abstract name for the permission to access a particular set of resources in an application. A role can be compared to a key that can open a lock. Many people might have a copy of the key. The lock doesn’t care who you are, only that you have the right key.

Some Other Terminology

The following terminology is also used to describe the security requirements of the Java EE platform:

• Principal: An entity that can be authenticated by an authentication protocol in a security service that is deployed in an enterprise. A principal is identified by using a principal name and authenticated by using authentication data.

• Security policy domain, also known as security domain or realm: A scope over which a common security policy is defined and enforced by the security administrator of the security service.

• Security attributes: A set of attributes associated with every principal. The security attributes have many uses: for example, access to protected resources and auditing of users. Security attributes can be associated with a principal by an authentication protocol.

• Credential: An object that contains or references security attributes used to authenticate a principal for Java EE services. A principal acquires a credential upon authentication or from another principal that allows its credential to be used.