按照demoHookPlugin写的Hook不起作用

[OAO]

问题描述

我照着demoHookPlugin写了个插件试图Hook系统提供的File类的构造方法

但好像他只能Hook外面这个框架调用的那些File对象，里面的应用调用的不知道为什么抓不到，连日志也不打印

具体表现在这个应用上就是拿到的MD5校验码完全一致，好像都没有经过Hook...

系统信息

OS: Android 6.0.1 (SDK 23)

Device: SM-P355C

在模拟器上也是这样...

Hook 代码

public class HookFile {
    public static String className = "java.io.File";
    public static String methodName = "<init>";
    public static String methodSig = "(Ljava/lang/String;)V";
    public static void hook(File thiz, String fileName) {
        Log.e("YAHFA", "open file "+fileName);
        if(fileName.equals("/system/framework/services.jar"))
        {
            Log.e("YAHFA", "Hacked Services");
            backup(thiz, "/sdcard/hack/services.jar");
            return;
        }
        if(fileName.equals("/system/framework/framework.jar"))
        {
            Log.e("YAHFA", "Hacked Framework");
            backup(thiz, "/sdcard/hack/framework.jar");
            return;
        }
        backup(thiz, fileName);
    }

    public static void backup(File thiz, String fileName) {
        Log.e("YAHFA", "should not be here");
        throw new UnsupportedOperationException("Stub!");
    }
}

源应用代码

public class HardwareInfo {
    public static String calculateMD5(File file) {
        String str = null;
        try{
            MessageDigest instance = MessageDigest.getInstance("MD5");
            InputStream fileInputStream = new FileInputStream(file);
            byte[] bArr = new byte[5242880];
            while (true) {
                int read = fileInputStream.read(bArr);
                if (read <= 0) {
                    break;
                }
                instance.update(bArr, 0, read);
            }
            fileInputStream.close();
            BigInteger bigInteger = new BigInteger(1, instance.digest());
            str = String.format("%32s", new Object[]{bigInteger.toString(16)}).replace(' ', '0');
        } catch (Throwable e)
        {
            Log.e("HardwareInfo","Error occured");
        }
        return str;
    }

    public static String getHardwareInfo(Context context) {
        StringBuilder str = new StringBuilder();
        str.append("FINGERPRINT: ");
        str.append(Build.FINGERPRINT);
        str.append("\n");
        str.append("service.jar: ");
        str.append(calculateMD5(new File("/system/framework/services.jar")));
        str.append("\n");
        str.append("framework.jar: ");
        str.append(calculateMD5(new File("/system/framework/framework.jar")));
        str.append("\n");
        return str.toString();
    }
}

日志

adb.exe shell "logcat | grep YAHFA"

03-17 16:12:56.282 17007 17007 I YAHFA-Native: init to SDK 23
03-17 16:12:56.282 17007 17007 I YAHFA   : Start hooking with item org.github.hookstring.HookFile
03-17 16:12:56.282 17007 17007 W YAHFA-Native: not enough capacity. Allocating...
03-17 16:12:56.282 17007 17007 I YAHFA-Native: Allocating done
03-17 16:12:56.282 17007 17007 I YAHFA-Native: target method is at 0x715baab0, hook method is at 0xb2ec0dc0, backup method is at 0xb2ec0d98
03-17 16:12:56.282 17007 17007 I YAHFA-Native: origin ep is 0x74a36775, new ep is 0xb2d34000
03-17 16:12:56.282 17007 17007 I YAHFA-Native: hook and backup done
03-17 16:12:56.352 17007 17007 E YAHFA   : open file /data/data/com.android.settings/app_fonts/sans.loc

没有一点报错信息

[OAO]

看到了另一个issue，原来是加载dex问题，不能从SD卡安装，克隆进去就好用了
希望作者写在README里
参考 #59