源码分析 | 咋嘞？你的IDEA过期了吧！加个Jar包就破解了，为什么？

2020 = 1024 + 996 | 404 + 404 + 404 + 404 + 404
2021 = 1024 + 997
2022 = 1024 + 9106
2023 = 1024 + 9107
...
20xx = 从今年开始可怕

itstack-demo-code-idea
└── src
    ├── main
    │   ├── java
    │   │   └── org.itstack.demo
    │   │       └── JetbrainsCrack.java
    │   └── resources	
    │       └── META-INF	
    │           └── MANIFEST.MF
    └── test
         └── java
             ├── com.jetbrains.ls.newLicenses
             │   └── DecodeCertificates.java			 
             └── org.itstack.demo.test
                 └── ApiTest.java

/**
 * 博客：http://bugstack.cn
 * 公众号：bugstack虫洞栈 | 更多原处优质干货
 * Agent 类，所有程序启动只要配置了 -javaagent: 都会走到 premain 方法
 */
public class JetbrainsCrack {

    public static void premain(String args, Instrumentation inst) {
        System.out.println("**************************************");
        System.out.println("*       公众号：bugstack虫洞栈       *");
        System.out.println("*     博客：https://bugstack.cn      *");
        System.out.println("*   你用剑，我用刀，好的代码都很烧！ *");
        System.out.println("**************************************");
        inst.addTransformer(new MethodEntryTransformer());
    }

    static class MethodEntryTransformer implements ClassFileTransformer {

        private Logger logger = LoggerFactory.getLogger(MethodEntryTransformer.class);

        public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException {

            try {
                if (className.equals("com/jetbrains/ls/newLicenses/DecodeCertificates")) {
                    ClassReader cr = new ClassReader(classfileBuffer);
                    ClassNode cn = new ClassNode();
                    cr.accept(cn, 0);
                    List<MethodNode> methodNodes = cn.methods;
                    for (MethodNode methodNode : methodNodes) {
                        if ("decodeLicense".equals(methodNode.name)) {
                            InsnList insns = methodNode.instructions;
                            //清除指令
                            insns.clear();
                            insns.add(new VarInsnNode(Opcodes.ALOAD, 1)); // 将本地指定的引用存入栈中
                            insns.add(new InsnNode(Opcodes.ARETURN));          // 从方法中返回引用类型的数据
                            // 访问结束
                            methodNode.visitEnd();
                            ClassWriter cw = new ClassWriter(0);
                            cn.accept(cw);
                            byte[] bytes = cw.toByteArray();
                            // 输出字节码到Class
                            this.outputClazz(bytes);
                            // 返回最新字节码
                            return cw.toByteArray();
                        }
                    }
                }
            } catch (Exception e) {
                return classfileBuffer;
            }

            return classfileBuffer;
        }

        private void outputClazz(byte[] bytes) {
            // 输出类字节码
            FileOutputStream out = null;
            try {
                out = new FileOutputStream("ASMDecodeCertificates.class");
                logger.info("ASM类输出路径：{}", (new File("")).getAbsolutePath());
                out.write(bytes);
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if (null != out) try {
                    out.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

    }

}

public class DecodeCertificates {

    public String decodeLicense(String usingKey) {
        // 模拟校验授权码
        return "usingKey is error："+ usingKey;
    }

}

/**
 * 博客：http://bugstack.cn
 * 公众号：bugstack虫洞栈 | 更多原处优质干货
 * 测试类配置 VM 参数
 * Idea VM options：-javaagent:E:\itstack\GIT\itstack.org\itstack-demo-code\itstack-demo-code-idea\target\itstack-demo-code-idea-1.0-SNAPSHOT.jar
 */
public class ApiTest {

    private static Logger logger = LoggerFactory.getLogger(ApiTest.class);

    public static void main(String[] args) throws Exception {
        DecodeCertificates decodeCertificates = new DecodeCertificates();
        // 模拟usingKey：认购有效期至2089年7月8日
        String license = decodeCertificates.decodeLicense("Subscription is active until July 8, 2089");
        logger.info("测试结果：{}", license);
    }

}

Manifest-Version: 1.0
Premain-Class: org.itstack.demo.JetbrainsCrack
Can-Redefine-Classes: true

<!-- 将javassist包打包到Agent中 -->
<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-shade-plugin</artifactId>
    <executions>
        <execution>
            <phase>package</phase>
            <goals>
                <goal>shade</goal>
            </goals>
        </execution>
    </executions>
    <configuration>
        <artifactSet>
            <includes>
                <include>asm:asm-all:jar:</include>
            </includes>
        </artifactSet>
    </configuration>
</plugin>

public class DecodeCertificates {

	public String decodeLicense(String usingKey) {
		// 模拟校验授权码
		return "usingKey is error："+ usingKey;
	}

}

package com.jetbrains.ls.newLicenses;

public class DecodeCertificates {
	public DecodeCertificates() {
	}

	public String decodeLicense(String usingKey) {
		return usingKey;
	}
}