Propagating security attributes among application servers

Use the security attribute propagation feature of WebSphere® Application Server to send security attribute information regarding the original login to other servers by using a token. This topic helps to configure WebSphere Application Server to propagate security attributes to other servers.

About this task

To fully enable security attribute propagation, you must configure the single sign-on (SSO), Common Secure Interoperability Version 2 (CSIv2) inbound, and CSIv2 outbound panels in the WebSphere Application Server administrative console. You can enable just the portions of security attribute propagation relevant to your configuration. For example, you can enable web propagation, which is propagation amongst front-end application servers, using either the push technique (DynaCache) or the pull technique (remote method to originating server).

You also can choose whether to enable Remote Method Invocation (RMI) outbound and inbound propagation, which is commonly called downstream propagation. Typically both types of propagation are enabled for any given cell.

Restriction: To prevent propagating the same security attributes among application servers multiple times, WebSphere Application Server verifies that a Lightweight Third Party Authentication (LTPA) token does not exist. Two cases can occur. Absence of the LTPA token tells the Application Server that propagation can proceed. Presence of the LTPA token indicates that propagation has occurred if the LTPA token has been generated within the cluster. However, in the second case, if the LTPA token is present, but has been generated by a server outside the cluster, such as by Tivoli® Access Manager, Lotus Domino, or a different Application Server cluster, security attributes are not propagated.

Complete the following steps to configure WebSphere Application Server for security attribute propagation:

Procedure

  1. Access the WebSphere Application Server administrative console by typing http://server_name:port_number/ibm/console.
    The administrative console address might differ if you have previously changed the port number.
  2. Click Security > Global security.
  3. Under Web and SIP security, click Single sign-on (SSO).
  4. Optional: Select the Interoperability Mode option if you must interoperate with servers that do not support security attribute propagation.
    Servers that do not support security attribute propagation receive the Lightweight Third Party Authentication (LTPA) token and the Propagation token, but ignore the security attribute information that they do not understand.
  5. Select the Web inbound security attribute propagation option.
    The Web inbound security attribute propagation option enables horizontal propagation, which allows the receiving SSO token to retrieve the login information from the original login server. If you do not enable this option, downstream propagation can occur if you enable the Security Attribute Propagation option on both the CSIv2 Inbound authentication and CSIv2 outbound authentication panels.

    Typically, you enable the web inbound security attribute propagation option if you need to gather dynamic security attributes set at the original login server that cannot be regenerated at the new front-end server. These attributes include any custom attributes that might be set in the PropagationToken token using the com.ibm.websphere.security.WSSecurityHelper application programming interfaces (APIs). You must determine whether enabling this option improves or degrades the performance of your system. While the option prevents some remote user registry calls, the deserialization and decryption of some tokens might impact performance. In some cases propagation is faster, especially if your user registry is the bottleneck of your topology. It is recommended that you measure the performance of your environment both by using and not using this option. When you test the performance, it is recommended that you test in the operating environment of the typical production environment with the typical number of unique users accessing the system simultaneously.

    When the Web inbound security attribute propagation option is enabled, security attributes are propagated to front-end application servers. When this option is disabled, the SSO token is used to log in and recreate the Subject from the user registry.

  6. Click Security > Global security. Under RMI/IIOP security, click CSIv2 inbound authentication.
    The Login configuration field specifies RMI_INBOUND as the system login configuration that is used for inbound requests. To add custom Java™ Authentication and Authorization Service (JAAS) login modules, complete the following steps:
    1. Click Security > Global security. Under Java Authentication and Authorization Service, click System logins.
      A list of the system login configurations is displayed. WebSphere Application Server provides the following pre-configured system login configurations: DEFAULT, LTPA, LTPA_WEB, RMI_INBOUND, RMI_OUTBOUND, SWAM, WEB_INBOUND, wssecurity.IDAssertion, and wssecurity.Signature. Do not delete these predefined configurations.
      Note: SWAM is deprecated in WebSphere Application Server Version 9.0 and will be removed in a future release.
    2. Click the name of the login configuration that you want to modify.
    3. Under Additional Properties, click JAAS Login Modules.
      The JAAS Login Modules panel is displayed, which lists all of the login modules that are processed in the login configuration. Do not delete the required JAAS login modules. Instead, you can add custom login modules before or after the required login modules. If you add custom login modules, do not begin their names with com.ibm.ws.security.server.

      You can specify the order in which the login modules are processed by clicking Set Order.

  7. Select the Security attribute propagation option on the CSIv2 inbound authentication panel.
    When you select Security Attribute Propagation, the server advertises to other application servers that it can receive propagated security attributes from another server in the same realm over the Common Secure Interoperability version 2 (CSIv2) protocol.
  8. Click Security > Global security. Under RMI/IIOP security, click CSIv2 Outbound authentication.
    The CSIv2 outbound authentication panel is displayed. The Login configuration field specifies RMI_OUTBOUND as the JAAS login configuration that is used for outbound configuration. You cannot change this login configuration. Instead, you can customize this login configuration by completing the substeps that are listed previously for CSIv2 Inbound authentication.
  9. Optional: Verify that the Security Attribute Propagation option is selected if you want to enable outbound Subject and security context token propagation for the Remote Method Invocation (RMI) protocol.
    When you select this option, WebSphere Application Server serializes the Subject contents and the PropagationToken contents. After the contents are serialized, the server uses the CSIv2 protocol to send the Subject and PropagationToken token to the target servers that support security attribute propagation. If the receiving server does not support security attribute tokens, WebSphere Application Server sends the Lightweight Third Party Authentication (LTPA) token only.
    Important: WebSphere Application Server propagates only the objects within the Subject that it can serialize. The server propagates custom objects on a best-effort basis.
    When Security Attribute Propagation is enabled, WebSphere Application Server adds marker tokens to the Subject to enable the target server to add additional attributes during the inbound login. During the commit phase of the login, the marker tokens and the Subject are marked as read-only and cannot be modified thereafter.
    [z/OS]Important: When using security attribute propagation, use the same LTPA keys in all cell configurations.
    [z/OS]When the Security Attribute Propagation option is enabled, allow the JAAS DESERIALIZE_ASYNCH_CONTEXT configuration to successfully refresh expired LTPA Tokens:
    1. Log in to the WebSphere Integrated Solution Console
    2. Select Security > Global Security > Java Authentication and Authorization Service > System Logins > DESERIALIZE_ASYNCH_CONTEXT > com.ibm.ws.security.server.lm.ltpaLoginModule.
    3. Create a custom property, com.ibm.ws.security.context.renewToken, and set the value to true.
    4. Save your changes and synchronize the nodes.
    5. Restart the server or servers.
    Setting the com.ibm.ws.security.context.renewToken property this way ensures that asynchronous beans succeed in deserializing expired security contexts when Security Attribute Propagation is disabled.
  10. Optional: Select the Custom Outbound Mapping option if you clear the Security Attribute Propagation option and you want to use the RMI_OUTBOUND login configuration.
    If neither the Custom Outbound Mapping option nor the Security Attribute Propagation option is selected, WebSphere Application Server does not call the RMI_OUTBOUND login configuration. If you need to plug in a credential mapping login module, you must select the Custom Outbound Mapping option.
  11. Optional: Specify trusted target realm names in the Trusted Target Realms field.
    By specifying these realm names, information can be sent to servers that reside outside the realm of the sending server to support inbound mapping that is at these downstream servers. To perform outbound mapping to a realm different from the current realm, you must specify the realm in this field so that you can get to this point without having the request rejected because of a realm mismatch. If you need WebSphere Application Server to propagate security attributes to another realm when a request is sent, you must specify the realm name in the Trusted Target Realms field. Otherwise, the security attributes are not propagated to the unspecified realm. You can add multiple target realms by adding a pipe (|) delimiter between each entry.
  12. Optional: Enable propagation for a pure client.
    For a pure client to propagate attributes added to the invocation Subject, you must add the following property to the sas.client.props file: com.ibm.CSI.rmiOutboundPropagationEnabled=true
    Note: The sas.client.props file is located at <WAS-HOME>/profiles/<ProfileName>/properties>.

Results

After completing these steps, you have configured WebSphere Application Server to propagate security attributes to other servers.