26.2. Configure Node Security in Library Mode

In Library mode, node authentication is configured directly in the JGroups configuration. JGroups can be configured so that nodes must authenticate each other when joining or merging with a cluster. The authentication uses SASL and is enabled by adding the SASL protocol to your JGroups XML configuration.
SASL relies on JAAS notions, such as CallbackHandlers, to obtain certain information necessary for the authentication handshake. Users must supply their own CallbackHandlers on both client and server sides.

Important

The JAAS API is only available when configuring user authentication and authorization, and is not available for node security.

Note

In the provided example, CallbackHandler classes are examples only, and not contained in the Red Hat JBoss Data Grid release. Users must provide the appropriate CallbackHandler classes for their specific LDAP implementation.

Example 26.4. Setting Up SASL Authentication in JGroups

<SASL mech="DIGEST-MD5"
    client_name="node_user"
    client_password="node_password"
    server_callback_handler_class="org.example.infinispan.security.JGroupsSaslServerCallbackHandler"
    client_callback_handler_class="org.example.infinispan.security.JGroupsSaslClientCallbackHandler"
    sasl_props="com.sun.security.sasl.digest.realm=test_realm" />
The above example uses the DIGEST-MD5 mechanism. Each node must declare the user and password it will use when joining the cluster.

Important

The SASL protocol must be placed before the GMS protocol in order for authentication to take effect.
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26.2.1. Simple Authorizing Callback Handler

For instances where a more complex Kerberos or LDAP approach is not needed the SimpleAuthorizingCallbackHandler class may be used. To enable this set both the server_callback_handler and the client_callback_handler to org.jgroups.auth.sasl.SimpleAuthorizingCallbackHandler, as seen in the below example: 
<SASL mech="DIGEST-MD5"
  client_name="node_user"
  client_password="node_password"
  server_callback_handler_class="org.jgroups.auth.sasl.SimpleAuthorizingCallbackHandler"
  client_callback_handler_class="org.jgroups.auth.sasl.SimpleAuthorizingCallbackHandler"
  sasl_props="com.sun.security.sasl.digest.realm=test_realm" />
The SimpleAuthorizingCallbackHandler may be configured either programmatically, by passing the constructor an instance of of java.util.Properties, or via standard Java system properties, set on the command line using the -DpropertyName=propertyValue notation. The following properties are available:
  • sasl.credentials.properties - the path to a property file which contains principal/credential mappings represented as principal=password .
  • sasl.local.principal - the name of the principal that is used to identify the local node. It must exist in the sasl.credentials.properties file.
  • sasl.roles.properties - (optional) the path to a property file which contains principal/roles mappings represented as principal=role1,role2,role3 .
  • sasl.role - (optional) if present, authorizes joining nodes only if their principal is.
  • sasl.realm - (optional) the name of the realm to use for the SASL mechanisms that require it
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26.2.2. Configure Node Authentication for Library Mode (DIGEST-MD5)

The behavior of a node differs depending on whether it is the coordinator node or any other node. The coordinator acts as the SASL server, with the joining or merging nodes behaving as SASL clients. When using the DIGEST-MD5 mechanism in Library mode, the server and client callback must be specified so that the server and client are aware of how to obtain the credentials. Therefore, two CallbackHandlers are required:
  • The server_callback_handler_class is used by the coordinator.
  • The client_callback_handler_class is used by other nodes.
The following example demonstrates these CallbackHandlers.

Example 26.5. Callback Handlers

<SASL mech="DIGEST-MD5"
      client_name="node_name"
      client_password="node_password"
      client_callback_handler_class="${CLIENT_CALLBACK_HANDLER_IN_CLASSPATH}"
      server_callback_handler_class="${SERVER_CALLBACK_HANDLER_IN_CLASSPATH}"
      sasl_props="com.sun.security.sasl.digest.realm=test_realm"
/>
JGroups is designed so that all nodes are able to act as coordinator or client depending on cluster behavior, so if the current coordinator node goes down, the next node in the succession chain will become the coordinator. Given this behavior, both server and client callback handlers must be identified within SASL for Red Hat JBoss Data Grid implementations.
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26.2.3. Configure Node Authentication for Library Mode (GSSAPI)

When performing node authentication in Library mode using the GSSAPI mechanism, the login_module_name parameter must be specified instead of callback.
This login module is used to obtain a valid Kerberos ticket, which is used to authenticate a client to the server. The server_name must also be specified, as the client principal is constructed as jgroups/$server_name@REALM.

Example 26.6. Specifying the login module and server on the coordinator node

<SASL mech="GSSAPI"
         server_name="node0/clustered"
         login_module_name="krb-node0"
         server_callback_handler_class="org.infinispan.test.integration.security.utils.SaslPropCallbackHandler" />
On the coordinator node, the server_callback_handler_class must be specified for node authorization. This will determine if the authenticated joining node has permission to join the cluster.

Note

The server principal is always constructed as jgroups/server_name, therefore the server principal in Kerberos must also be jgroups/server_name. For example, if the server name in Kerberos is jgroups/node1/mycache, then the server name must be node1/mycache.
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