SandHook

SandHook

• Android ART Hook
• Native Inline Hook

Version

Chinese

中文文档以及实现

中文 Blog

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arch support

• ARM64
• ARM32(no tested)
• Thumb-2

OS

4.4(ART Runtime) - 11.0 dev-preview-1

Project Struct

• annotation
  annotation api
• hooklib
  core lib of art hook
• nativehook
  lib of native hook
• xposedcompat
  stable implement of xposed api compat for sandhook
• xposedcompat_new
  annother implement of xposed api compat for sandhook(hook more fast first time)
• hookers
  hook plugin demo for annotation api

how to use

implementation 'com.swift.sandhook:hooklib:4.2.0'
// need for android 11
implementation 'com.swift.sandhook:nativehook:4.2.0'

Annotation API

---

• hook method must be a static method
• first par must be this if method is not static
• method description must “same”(can be isAssignableFrom) with origin method
• backup method same with above

@HookClass(Activity.class)
//@HookReflectClass("android.app.Activity")
public class ActivityHooker {

    @HookMethodBackup("onCreate")
    @MethodParams(Bundle.class)
    static Method onCreateBackup;

    @HookMethodBackup("onPause")
    static HookWrapper.HookEntity onPauseBackup;

    @HookMethod("onCreate")
    @MethodParams(Bundle.class)
    public static void onCreate(Activity thiz, Bundle bundle) throws Throwable {
        Log.e("ActivityHooker", "hooked onCreate success " + thiz);
        SandHook.callOriginByBackup(onCreateBackup, thiz, bundle);
    }

    @HookMethod("onPause")
    public static void onPause(@ThisObject Activity thiz) throws Throwable {
        Log.e("ActivityHooker", "hooked onPause success " + thiz);
        onPauseBackup.callOrigin(thiz);
    }

}



//or like this:

@HookClass(TestClass.class)
public class NewAnnotationApiHooker {

    @HookMethod("testNewHookApi")
    public static void onTestNewHookApi(@ThisObject TestClass thiz, @Param("com.swift.sandhook.MainActivity") Activity activity, int a) {
        Log.e("TestClassHook", "testNewHookApi been hooked");
        onTestNewHookApiBackup(thiz, activity, a);
    }

    @HookMethodBackup("testNewHookApi")
    public static void onTestNewHookApiBackup(@ThisObject TestClass thiz, @Param("com.swift.sandhook.MainActivity") Activity activity, int a) {
        onTestNewHookApiBackup(thiz, activity, a);
    }

}



//first set debuggable
SandHookConfig.DEBUG = BuildConfig.DEBUG;

and

//add hookers
SandHook.addHookClass(CtrHook.class, LogHooker.class, CustmizeHooker.class, ActivityHooker.class, ObjectHooker.class);

you can also use:
SanHook.public static boolean hook(Member target, Method hook, Method backup) {}

if hookers is in plugin(like xposed):

provided 'com.swift.sandhook:hookannotation:4.2.0'

in your plugin

if OS <= 5.1 backup method can call itself to avoid be inlining

Xposed API

---

Now you can use Xposed api:

We have two different implements:

//stable
implementation 'com.swift.sandhook:xposedcompat:4.2.0'

//or

//hook fast first time
implementation 'com.swift.sandhook:xposedcompat_new:4.2.0'

//setup for xposed
//for xposed compat only(no need xposed comapt new)
XposedCompat.cacheDir = getCacheDir();

//for load xp module(sandvxp)
XposedCompat.context = this;
XposedCompat.classLoader = getClassLoader();
XposedCompat.isFirstApplication= true;

//do hook
XposedHelpers.findAndHookMethod(Activity.class, "onResume", new XC_MethodHook() {
      @Override
      protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
          super.beforeHookedMethod(param);
          Log.e("XposedCompat", "beforeHookedMethod: " + param.method.getName());
      }

      @Override
      protected void afterHookedMethod(MethodHookParam param) throws Throwable {
          super.afterHookedMethod(param);
          Log.e("XposedCompat", "afterHookedMethod: " + param.method.getName());
      }
});

Notice

Disable Inline

JIT inline

We can do nothing to prevent some methods been inlined before app start, but we can try to disable VM Jit Inline after launch.

if you will hook some method that could be inlined, please call SandHook.disableVMInline()(OS >= 7.0) in Application.OnCreate()

Inline by dex2oat

Background dex2oat

SandHook.tryDisableProfile(getPackageName());

dex2oat by DexClassLoader

SandHook.disableDex2oatInline(fullyDisableDex2oat);

or

ArtDexOptimizer.dexoatAndDisableInline to dex2oat manuly

Deoptimize(Boot Image)

You can also deoptimize a caller that inlined your hook method by SandHook.deCompile(caller), just implement >= 7.0

Hidden API

SandHook.passApiCheck();

To bypass hidden api on P & Q

Debuggable

You must set debuggble of the target hook process before init when OS >= 8.0.

SandHookConfig.DEBUG =

Native Hook

simple hook(no backup)

#include “includes/sandhook.h”

bool nativeHookNoBackup(void* origin, void* hook);

need backup origin method

#include “sandhook_native.h”

void* SandInlineHook(void* origin, void* replace);

void* SandInlineHookSym(const char* so, const char* symb, void* replace);

return is backup method

break point

you can insert a break point in body of method(not only start of method), so you can read/write registers in break point.

bool SandBreakPoint(void* origin, void (*callback)(REG[]));

bool SandSingleInstBreakPoint(void *origin, BreakCallback(callback));

short method

#include “sandhook_native.h”

void* SandSingleInstHook(void* origin, void* replace);

void* SandSingleInstHookSym(const char* so, const char* symb, void* replace);

use it when your method is <= 16bytes(64bit)/8bytes(32bit)

SandSingleInstHook only need 4bytes length

more

• disassembler (only implement important instructions)
• assembler (only implement important instructions)

Demo

SandVXPosed

non-Root Xposed Environment Demo (VirtualApp with SandHook):

https://github.com/ganyao114/SandVXposed

EdXposed(SandHook Brunch)

Unofficial xposed framework >= 8.0

See release above

https://github.com/ElderDrivers/EdXposed

Android Q(10.0)

in MyApp.java

//if you want test Android Q, please set true, because SDK_INT of Android Q is still 28 public final static boolean testAndroidQ = false;

References

• Epic:https://github.com/tiann/epic
• Yahfa:https://github.com/rk700/YAHFA