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@RikkaW
Last active October 2, 2024 14:10
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show window in app_process (impossible to work from Android 14 QPR 3 or Android 15, as addView requires the calling process an Android app process)
token = new Binder();
try {
Context _context = android.app.ActivityThread.systemMain().getSystemContext();
final Context context = new ContextWrapper(_context) {
@Override
public Object getSystemService(String name) {
if (Context.WINDOW_SERVICE.equals(name)) {
WindowManager wm = (WindowManager) super.getSystemService(name);
if (wm != null) {
((android.view.WindowManagerImpl) wm).setDefaultToken(token);
}
return wm;
}
return super.getSystemService(name);
}
};
context.setTheme(android.R.style.Theme_Material_Light);
CharSequence label = context.getPackageManager().getApplicationLabel(context.getPackageManager().getApplicationInfo("com.android.settings", 0));
LogUtils.i("label " + label);
android.widget.Toast.makeText(context, "test", Toast.LENGTH_LONG).show();
LogUtils.i("toast");
android.view.WindowManager wm = context.getSystemService(WindowManager.class);
LogUtils.i("class: " + wm.getClass().getName());
//((android.view.WindowManagerImpl) wm).setDefaultToken(token);
LinearLayout root = new LinearLayout(context);
root.setBackground(new ColorDrawable(0xffffffff));
TextView textView = new TextView(context);
textView.setText("test");
root.addView(textView);
Button button = new Button(context);
button.setSoundEffectsEnabled(false);
button.setText("test");
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(context, "?!", Toast.LENGTH_LONG).show();
}
});
root.addView(button);
WindowManager.LayoutParams params = new WindowManager.LayoutParams(
WindowManager.LayoutParams.WRAP_CONTENT,
WindowManager.LayoutParams.WRAP_CONTENT,
WindowManager.LayoutParams.TYPE_SYSTEM_DIALOG,
WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL,
PixelFormat.TRANSLUCENT);
params.gravity = Gravity.CENTER;
params.x = 0;
params.y = 0;
wm.addView(root, params);
} catch (Throwable tr) {
LogUtils.e(tr.getMessage(), tr);
}
@huynhtanloc2612
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huynhtanloc2612 commented Jul 31, 2023

Thanks @RikkaW for your information and advices.
Such knowledge is completely new to me and it is quite interesting. I sometime play with Android API but since I knew about the app_process magic from scrcpy tool, I was very impresive. I want to learn more about it and find out what else it can do... but looks there is very few online information for beginers. By following and trying some projects like this, the answers of @twaik and yours help me learn a lot new knowledge about it. Thank you.
If posible, I hope you could point me to where to learn and play with aidl API for beginers.

@twaik
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twaik commented Mar 26, 2024

@RikkaW I have some problems with creating some overlay from process started with app_process in application sandbox of other app.
I know "window" service is inaccessible from processes started this way, but I am sending IBinder of that service from Activity via AIDL and injecting it to ServiceManager's sCache manually, so WindowManagerGlobal can access it.
I am trying to create overlay with this code:

    public void window(IBinder windowManager) {
        try {
            Field sCache = Class.forName("android.os.ServiceManager").getDeclaredField("sCache");
            sCache.setAccessible(true);
            Method m = sCache.getType().getDeclaredMethod("put", Object.class, Object.class);
            m.invoke(sCache.get(null), "window", windowManager);

            handler.post(() -> {
                Context context = ctx;
                WindowManager wm = context.getSystemService(WindowManager.class);
                Binder token = new Binder();
                context = new ContextWrapper(context) {
                    @Override
                    public Object getSystemService(String name) {
                        if (Context.WINDOW_SERVICE.equals(name)) {
                            WindowManager wm = (WindowManager) super.getSystemService(name);
                            if (wm != null)
                                ((android.view.WindowManagerImpl) wm).setDefaultToken(token);
                            return wm;
                        }
                        return super.getSystemService(name);
                    }
                };
                Button button = new Button(context);
                button.setSoundEffectsEnabled(false);
                button.setText("test");
                WindowManager.LayoutParams params = new WindowManager.LayoutParams(
                        WindowManager.LayoutParams.WRAP_CONTENT,
                        WindowManager.LayoutParams.WRAP_CONTENT,
                        WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY,
                        WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL,
                        PixelFormat.TRANSLUCENT);

                params.gravity = Gravity.CENTER;
                params.x = 0;
                params.y = 0;
                wm.addView(button, params);
            });
        } catch (Exception e) {
            e.printStackTrace(System.err);
        }
    }

But I am getting only this unclear exception

android.view.WindowManager$BadTokenException: Unable to add window android.view.ViewRootImpl$W@e51bfa1 -- permission denied for window type 2038
        at android.view.ViewRootImpl.setView(ViewRootImpl.java:1092)
        at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:409)
        at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:109)
        at com.termux.x11.CmdEntryPoint.lambda$windowManager$3(CmdEntryPoint.java:269)
        at com.termux.x11.CmdEntryPoint.$r8$lambda$MIV7qHiVNsG1buhNHJnI7A8pV3A(CmdEntryPoint.java:0)
        at com.termux.x11.CmdEntryPoint$$ExternalSyntheticLambda1.run(R8$$SyntheticClass:0)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:223)
        at com.termux.x11.CmdEntryPoint.main(CmdEntryPoint.java:62)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.termux.x11.Loader.main(Loader.java:26)
        at com.android.internal.os.RuntimeInit.nativeFinishInit(Native Method)
        at com.android.internal.os.RuntimeInit.main(RuntimeInit.java:399)

Both activity I am sending IBinder from and application where I want to start this snippet have "Draw over apps" permission but it does not help.
I tried to make a proxy for IBinder to make my snippet inherit Uid of another application (which owns Activity) with adding this code to ContextWrapper


                    public UserHandle getUser() {
                        try {
                            return (UserHandle) UserHandle.class.getDeclaredMethod("of", int.class).invoke(null, Binder.getCallingUid() / 100000);
                        } catch (IllegalAccessException | InvocationTargetException | NoSuchMethodException e) {
                            throw new RuntimeException(e);
                        }
                    }
                    public int getUserId() {
                        return Binder.getCallingUid() / 100000;
                    }

and wrapping "window"'s IBinder with

                    Binder proxy = new Binder() {
                        IBinder target = (IBinder) Class.forName("android.os.ServiceManager").getDeclaredMethod("getService", String.class).invoke(null, "window");
                        @Override protected boolean onTransact(int code, Parcel data, Parcel reply, int flags) throws RemoteException {
                            return target.transact(code, data, reply, flags);
                        }
                    };

But it does not seem to work, I am getting the same exception.

Seems like I found a reason in system-wide logcat.

03-26 13:39:36.231   536  2972 E AppOps  : noteOperation
03-26 13:39:36.231   536  2972 E AppOps  : java.lang.SecurityException: Specified package android under uid 10162 but it is really 1000
03-26 13:39:36.231   536  2972 E AppOps  :      at com.android.server.appop.AppOpsService.verifyAndGetBypass(AppOpsService.java:3874)
03-26 13:39:36.231   536  2972 E AppOps  :      at com.android.server.appop.AppOpsService.noteOperationUnchecked(AppOpsService.java:3030)
03-26 13:39:36.231   536  2972 E AppOps  :      at com.android.server.appop.AppOpsService.noteOperationImpl(AppOpsService.java:3018)
03-26 13:39:36.231   536  2972 E AppOps  :      at com.android.server.appop.AppOpsService.noteOperation(AppOpsService.java:3001)
03-26 13:39:36.231   536  2972 E AppOps  :      at android.app.AppOpsManager.noteOpNoThrow(AppOpsManager.java:7382)
03-26 13:39:36.231   536  2972 E AppOps  :      at com.android.server.policy.PhoneWindowManager.checkAddPermission(PhoneWindowManager.java:2150)
03-26 13:39:36.231   536  2972 E AppOps  :      at com.android.server.wm.WindowManagerService.addWindow(WindowManagerService.java:1383)
03-26 13:39:36.231   536  2972 E AppOps  :      at com.android.server.wm.Session.addToDisplayAsUser(Session.java:176)
03-26 13:39:36.231   536  2972 E AppOps  :      at android.view.IWindowSession$Stub.onTransact(IWindowSession.java:679)
03-26 13:39:36.231   536  2972 E AppOps  :      at com.android.server.wm.Session.onTransact(Session.java:139)
03-26 13:39:36.231   536  2972 E AppOps  :      at android.os.Binder.execTransactInternal(Binder.java:1154)
03-26 13:39:36.231   536  2972 E AppOps  :      at android.os.Binder.execTransact(Binder.java:1123)

@twaik
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twaik commented Mar 26, 2024

Ok, I figured it out.


    public void windowManager(IBinder binder) {
        try {
            Field sCache = Class.forName("android.os.ServiceManager").getDeclaredField("sCache");
            sCache.setAccessible(true);
            Method m = sCache.getType().getDeclaredMethod("put", Object.class, Object.class);
            m.invoke(sCache.get(null), "window", binder);

            handler.post(() -> {
                Context context = android.app.ActivityThread.systemMain().getSystemContext();
                WindowManager wm = context.getSystemService(WindowManager.class);
                Binder token = new Binder();
                context = new ContextWrapper(context) {
                    @Override
                    public Object getSystemService(String name) {
                        if (Context.WINDOW_SERVICE.equals(name)) {
                            WindowManager wm = (WindowManager) super.getSystemService(name);
                            if (wm != null)
                                ((android.view.WindowManagerImpl) wm).setDefaultToken(token);
                            return wm;
                        }
                        return super.getSystemService(name);
                    }

                    @Override
                    public Looper getMainLooper() {
                        return Looper.myLooper();
                    }
                };
                View view = new View(context) {
                    final Paint paint = new Paint();
                    @Override
                    protected void onDraw(@NonNull Canvas canvas) {
                        super.onDraw(canvas);
                        paint.setStyle(Paint.Style.FILL);
                        paint.setColor(Color.RED);
                        canvas.drawRect(0, 0, getWidth(), getHeight(), paint);
                    }
                };
                WindowManager.LayoutParams params = new WindowManager.LayoutParams(
                        100,  100, WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY,
                        WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL,
                        PixelFormat.OPAQUE);

                params.gravity = Gravity.CENTER;
                params.x = 0;
                params.y = 0;
                params.packageName = "com.termux";
                wm.addView(view, params);
            });
        } catch (Exception e) {
            e.printStackTrace(System.err);
        }
    }

And it works on Android 11.
Thanks @RikkaW.

@twaik
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twaik commented Mar 26, 2024

And unfortunately I am getting this on Android 12.

java.lang.NullPointerException
        at android.os.Parcel.createExceptionOrNull(Parcel.java:2431)
        at android.os.Parcel.createException(Parcel.java:2409)
        at android.os.Parcel.readException(Parcel.java:2392)
        at android.os.Parcel.readException(Parcel.java:2334)
        at com.android.internal.app.IAppOpsService$Stub$Proxy.reportRuntimeAppOpAccessMessageAndGetConfig(IAppOpsService.java:1666)
        at android.app.AppOpsManager$1.reportStackTraceIfNeeded(AppOpsManager.java:290)
        at android.app.AppOpsManager$1.onNoted(AppOpsManager.java:265)
        at android.app.AppOpsManager.readAndLogNotedAppops(AppOpsManager.java:9359)
        at android.os.Parcel.readExceptionCode(Parcel.java:2356)
        at android.os.Parcel.readException(Parcel.java:2331)
        at android.view.IWindowSession$Stub$Proxy.addToDisplayAsUser(IWindowSession.java:1374)
        at android.view.ViewRootImpl.setView(ViewRootImpl.java:1119)
        at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:399)
        at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:133)
        at com.termux.x11.CmdEntryPoint.lambda$windowManager$3(CmdEntryPoint.java:286)
        at com.termux.x11.CmdEntryPoint.$r8$lambda$MIV7qHiVNsG1buhNHJnI7A8pV3A(CmdEntryPoint.java:0)
        at com.termux.x11.CmdEntryPoint$$ExternalSyntheticLambda1.run(R8$$SyntheticClass:0)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loopOnce(Looper.java:201)
        at android.os.Looper.loop(Looper.java:288)
        at com.termux.x11.CmdEntryPoint.main(CmdEntryPoint.java:71)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.termux.x11.Loader.main(Loader.java:26)
        at com.android.internal.os.RuntimeInit.nativeFinishInit(Native Method)
        at com.android.internal.os.RuntimeInit.main(RuntimeInit.java:355)
Caused by: android.os.RemoteException: Remote stack trace:
        at com.android.internal.util.AnnotationValidations.validate(AnnotationValidations.java:129)
        at android.app.SyncNotedAppOp.<init>(SyncNotedAppOp.java:227)
        at android.app.SyncNotedAppOp$1.createFromParcel(SyncNotedAppOp.java:243)
        at android.app.SyncNotedAppOp$1.createFromParcel(SyncNotedAppOp.java:235)
        at com.android.internal.app.IAppOpsService$Stub.onTransact(IAppOpsService.java:728)

Any suggestions?

@RikkaW
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Author

RikkaW commented Mar 26, 2024

Change opPackageName? I don't remember:(

Btw, this will never work starting from Android 14 QPR 3 or Android 15, as addView now checks if the calling process is a valid Android app process.

@twaik
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twaik commented Mar 26, 2024

Maybe there is some workaround for this? The most important thing I need is to draw something as an overlay from background process.
I am not writing viruses. Simply some oems put code to limit GPU performance of background apps.
Maybe SurfaceControl.Transactions?

@JacobTDC
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JacobTDC commented Sep 30, 2024

From @huynhtanloc2612:

Hi @twaik You was correct. After I made subclass with a separated file MyContext.class, above error disappeared.

However, after code run, it has new below error. Do you have any advice?

java.lang.SecurityException: Given calling package android does not match caller's uid 2000 at ........

Late reply, I know, but the solution to this issue is to wrap your context to override getOpPackageName(), like so:

Context context = new ContextWrapper(_context) {
   /* @Override getSystemService() here if you want, not necessary for Toasts */

  @Override
  public String getOpPackageName() {
    return "com.android.shell"; // aka ADB shell package name
  }
};

I successfully managed to get a toast to show on Android 14 with the following:

Context _context = ActivityThread.systemMain().getSystemContext();

Context context = new ContextWrapper(_context) {
  @Override
  public String getOpPackageName() {
    // I actually used "com.termux" here, because I was playing around with
    // this in Termux, but, no matter.
    return "com.android.shell"; // aka ADB shell package name
  }
};

Toast.makeText(context, "test", Toast.LENGTH_LONG).show();

@huynhtanloc2612
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Thanks @JacobTDC for your comment
I've tried your suggestion

public class ShowToast {
    public static void main(String[] args) {
        Binder token = new Binder();
        Looper.prepareMainLooper();
        try{
            Context _context = ActivityThread.systemMain().getSystemContext();
            Context context = new ContextWrapper(_context) {
                @Override
                public String getOpPackageName() {
                  return "com.android.shell"; // aka ADB shell package name
                }
            };
            Toast.makeText(context, "test", Toast.LENGTH_LONG).show();
        } catch (Throwable tr) {
            tr.printStackTrace(System.err);
        }
    }
}

but I still got the below error on Galaxy phone with Android 14

$ adb shell app_process -cp /data/local/tmp/toast.dex / com.htl.toast14.ShowToast

java.lang.SecurityException: Given calling package android does not match caller's uid 2000
	at android.os.Parcel.createExceptionOrNull(Parcel.java:3069)
	at android.os.Parcel.createException(Parcel.java:3053)
	at android.os.Parcel.readException(Parcel.java:3036)
	at android.os.Parcel.readException(Parcel.java:2978)
	at android.app.IActivityManager$Stub$Proxy.getContentProvider(IActivityManager.java:6393)
	at android.app.ActivityThread.acquireProvider(ActivityThread.java:8160)
	at android.app.ContextImpl$ApplicationContentResolver.acquireProvider(ContextImpl.java:3838)
	at android.content.ContentResolver.acquireProvider(ContentResolver.java:2539)
	at android.provider.Settings$ContentProviderHolder.getProvider(Settings.java:3328)
	at android.provider.Settings$NameValueCache.getStringForUser(Settings.java:3595)
	at android.provider.Settings$System.getStringForUser(Settings.java:4362)
	at android.provider.Settings$System.getIntForUser(Settings.java:4493)
	at android.provider.Settings$System.getInt(Settings.java:4465)
	at android.widget.Toast.checkGameHomeAllowList(Toast.java:1108)
	at android.widget.Toast.show(Toast.java:313)
	at com.htl.toast14.ShowToast.main(ShowToast.java:28)
	at com.android.internal.os.RuntimeInit.nativeFinishInit(Native Method)
	at com.android.internal.os.RuntimeInit.main(RuntimeInit.java:395)
Caused by: android.os.RemoteException: Remote stack trace:
	at com.android.server.am.ContentProviderHelper.getContentProvider(ContentProviderHelper.java:148)
	at com.android.server.am.ActivityManagerService.getContentProvider(ActivityManagerService.java:8700)
	at android.app.IActivityManager$Stub.onTransact(IActivityManager.java:3091)
	at com.android.server.am.ActivityManagerService.onTransact(ActivityManagerService.java:3202)
	at android.os.Binder.execTransactInternal(Binder.java:1375)

Do you have any idea?
And can you show your full code?
Thanks.

@JacobTDC
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JacobTDC commented Oct 1, 2024

@huynhtanloc2612, the following works for me, I tested it in ADB as well.

$ adb shell app_process -cp /data/local/tmp/toast.dex /system/bin/ { class/package path }.ShowToast
public class ShowToast {
  public static final void main(String[] args) {
    Looper.prepare();

    ActivityThread activityThread = ActivityThread.systemMain();

    Context _context = activityThread.getSystemContext();
    Context context = new ContextWrapper(_context) {
      @Override
      public String getOpPackageName() {
        return "com.android.shell";
      }
    };

    // Maybe create a `new Handler(Looper.myLooper())` and wrap this
    // in `handler.post(() -> { ... }); Looper.loop();` if it doesn't work?
    // If you do, don't forget to add `Looper.myLooper().quit[Safely]()`
    // inside the `handler.post(() -> { ... });`.
    Toast.makeText(context, "test", Toast.LENGTH_LONG).show();
  }
}

If that doesn't work, maybe try something like this for creating and wrapping the context:

  static Context createPackageContext(String packageName) {
    Context sysCtx = ActivityThread.systemMain().getSystemContext();

    Context _context;
    try {
      _context = (Context) Context.class
        .getMethod("createPackageContextAsUser", new Class[] {
          String.class,
          int.class,
          UserHandle.class })
        .invoke(sysCtx, packageName, 0, Process.myUserHandle());
    } catch (Exception exc) {
      throw new RuntimeException(exc);
    }

    return new ContextWrapper(_context) {
      @Override
      public String getOpPackageName() {
        return packageName;
      }
    };
  }

What device are you using? I see you're using a Galaxy. That could make a difference, but I'm not sure. I'm using a Google Pixel 8 Pro.

@huynhtanloc2612
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Thanks @JacobTDC ,
Try your above suggestions but the same error happens when it executes Toast.makeText(...).show()
java.lang.SecurityException: Given calling package android does not match caller's uid 2000

I think it requires Android app process as the note of @RikkaW "addView requires the calling process an Android app process"

@D-R-99
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D-R-99 commented Oct 2, 2024

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