[Version 5.0.2 and later]Understanding Java 2 Platform, Enterprise Edition identities and operating system thread identities

Understanding the different types of identities: A WebSphere Application Server user is identified using an identity that must be authenticated by WebSphere Application Server in order to access a WebSphere Application Server application in a secure environment. The WebSphere Application Server authenticates the user identity and represents the user with a Java Authentication and Authorization Service (JAAS) subject. A subject contains one or more principals (which are technology-dependent representations of the authenticated user identity). More detail follows:

User identities
J2EE identity
The user identity authenticated by WebSphere and used for access control decisions made by the WebSphere Application Server at Java 2 Platform, Enterprise Edition (J2EE) runtime (such as the user identity associated with a J2EE application request and used in EJB method permission access control decisions).
Operating system (OS) identity
The user identity authenticated by the underlying operating system and used for access control decisions made by the OS and its subsystems (such as the user identity associated with a WebSphere Application Server for z/OS servant region by the SAF STARTED class facility and used by the file system for access control decisions when the server attempts to access files).
Thread identity
Java thread identity
The J2EE identity currently associated with a Java thread managed by the WebSphere J2EE runtime (a Java thread is the JVM's representation of a thread). The Java thread identity is associated with an operating system (OS) thread, but the Java virtual machine (JVM) manages the user identity on the Java representation of the thread - separate from the user identity that the operating system manages on the operating system thread. The J2EE identity is current on the Java thread for the life of the a given application request.
OS thread identity
The operating system identity currently associated with the operating system thread. The OS thread identity is typically the user identity assigned to servant region and is normally not the same as the Java thread identity. Note that J2EE maintains a J2EE identity that corresponds to the OS thread identity assigned to the servant region. This J2EE identity can be used as a RunAs identity.
RunAs identity
The J2EE identity chosen as the Java thread identity for a given J2EE application request (based on the RunAs deployment descriptor policy on an EJB invoked within the J2EE application request). The J2EE identity is normally the identity of the authenticated user who has made the J2EE application request. WebSphere Application Server RunAs policy allows three choices in assigning the Java thread identity for the current request:
  1. Assign the client (for example, user) J2EE identity - also referred to as selecting RunAs of "Caller"
  2. Assign the server's J2EE identity
  3. Assign the J2EE identity that is in the specified role
Web Application J2EE identity
A Web application can run with a J2EE identity. For example, in a Web application using Basic Authentication or Form-based authentication the J2EE identity is the user identity used in basic authentication or form-based authentication logon. In certain contexts, this J2EE identity is used with Web applications in the same ways as the RunAs identity is used with EJBs, (such as together with connector thread identity support).

When security is enabled, each WebSphere Application Server for z/OS request that invokes a J2EE component is authenticated to ensure that an authorized user is requesting access. A user is represented by a J2EE identity (also called a JAAS subject). This J2EE identity contains one or more principals, and each principal corresponds to a specific user identity. This association is managed by the WebSphere Application Server. The J2EE identity and operating system OS thread identity are associated with each other because they have the same name and represent the same user.

WebSphere Application Server for z/OS dispatches component requests in one of its available servant processes. Within the servant process the component request is dispatched on a Java thread. A Java thread is then mapped internally by the Java Virtual Machine (JVM) to a z/OS task control block (TCB). A TCB is an operating system thread and is considered part of the native process infrastructure. A servant process has a OS identity assigned to it when it starts. The z/OS security policy uses the SAF STARTED class facility to assign the identity.

servant process

J2EE authorization decisions including role authorization and permission checking are determined using the J2EE identity. Through a configuration setting, role authorization checking can be delegated to the underlying operating system security manager (such as System Authorization Facility (SAF)), in which case the associated operating system OS identity is used in the role authorization decision.

Some resource managers on z/OS use the OS thread identity to make authorization decisions. For example, file system access control is determined entirely based on which OS thread identity is currently on the TCB when the file is accessed. Similarly, local Java database connectivity (JDBC) connections to Database 2 (DB2) for z/OS use the TCB OS thread identity as the authorization identity under certain configurations. For resource managers that use the OS thread identity such as DB2 for z/OS (and unlike the file system) that applications access through Java Message Service (JMS), JDBC, or J2EE Connector Architecture (JCA) connectors managed by the WebSphere Application Server for z/OS connection management, we say that the connectors to these z/OS resource managers "use operating system thread security". For more information, refer to:





Searchable topic ID:   csecunderstandj2eenativeid
Last updated: Jun 21, 2007 9:56:50 PM CDT    WebSphere Application Server for z/OS, Version 5.0.2
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