Bypass android usb host permission confirmation dialog on Android 9

Question

Before Android 9 I could bypass android usb host permission confirmation dialog by using root, systemizing my app and using next usb classes https://stackoverflow.com/a/1537

Answer 1

We can solve it by entering:

adb shell
su
settings put global hidden_api_policy_pre_p_apps  1
settings put global hidden_api_policy_p_apps 1

Restrictions on non-SDK interfaces (Android 9): https://developer.android.com/distribute/best-practices/develop/restrictions-non-sdk-interfaces

And then grantDevicePermission method will be available again through reflection on Android 9:

public static boolean grantAutomaticUsbPermissionRoot(Context context, UsbDevice usbDevice) {
    try {
        PackageManager pkgManager = context.getPackageManager();
        ApplicationInfo appInfo = pkgManager.getApplicationInfo(context.getPackageName(), PackageManager.GET_META_DATA);

        Class serviceManagerClass = Class.forName("android.os.ServiceManager");
        Method getServiceMethod = serviceManagerClass.getDeclaredMethod("getService", String.class);
        getServiceMethod.setAccessible(true);
        android.os.IBinder binder = (android.os.IBinder)getServiceMethod.invoke(null, Context.USB_SERVICE);

        Class iUsbManagerClass = Class.forName("android.hardware.usb.IUsbManager");
        Class stubClass = Class.forName("android.hardware.usb.IUsbManager$Stub");
        Method asInterfaceMethod = stubClass.getDeclaredMethod("asInterface", android.os.IBinder.class);
        asInterfaceMethod.setAccessible(true);
        Object iUsbManager=asInterfaceMethod.invoke(null, binder);

        final Method grantDevicePermissionMethod = iUsbManagerClass.getDeclaredMethod("grantDevicePermission", UsbDevice.class, int.class);
        grantDevicePermissionMethod.setAccessible(true);
        grantDevicePermissionMethod.invoke(iUsbManager, usbDevice,appInfo.uid);
        return true;
    } catch (Exception e) {
        e.printStackTrace();
        return false;
    }
}

p.s. you need root of course and systemize your app (move to /system/priv-app/)