Grant USB permissions as device owner

Question

A device owner can grant runtime permissions to a third-party app using DevicePolicyManager.setPermissionGrantState() to avoid user prompts.

But is there any way for a device owner to grant USB permissions as well, so that this app gets access to plugged USB devices without user prompt ?

I've tried to call UsbManager.grantPermission() (with reflection) but it raises a SecurityException since it requires the MANAGE_USB permission which is granted only to system apps (and not to device owner, obviously).

NB: I'm looking for a solution working on a non-root & non-custom Android system, the device owner app is set using Android Enterprise provisioning methods.

Take a look here, if it helps: https://stackoverflow.com/questions/13647547/android-usb-automatically-grant-permission/33555752 — Gaurav Mall, Jul 02 '19 at 04:56
@GauravMall Unfortunately all the suggested answers require to be a system app — sdabet, Jul 02 '19 at 10:23
Yeah, sorry, that detail just passed over my head. I don't know how. Did it help you, however? — Gaurav Mall, Jul 02 '19 at 14:20
@GauravMall Not really. Surprinsingly it feels like an impossible thing to do. — sdabet, Jul 03 '19 at 15:54
Did you find a solution for it? Even UsbManager.grantPermission() (with reflection) deosn't work anymore on Android 9 with root system app — user924, Aug 23 '19 at 08:20
found solution for Android 9 https://stackoverflow.com/a/57622623/7767664 — user924, Aug 23 '19 at 08:43
@user924 gives me an error: "W/System.err: java.lang.reflect.InvocationTargetException" in "grantDevicePermissionMethod.invoke(iUsbManager, usbDevice,appInfo.uid); " — LucasRT, Sep 11 '19 at 06:01

Wojciech Sadurski · Answer 1 · 2019-05-08T12:14:27.797

4

There is a special system config to disable USB permission dialogs: https://github.com/aosp-mirror/platform_frameworks_base/blob/8ff4a5a5b510e724b25ac00369696594bb0c9fdc/core/res/res/values/config.xml#L2283

Maybe you can also change it at runtime with root privileges using setprop.

Another way is to customize the UsbUserSettingsManager class, specifically this method: https://android.googlesource.com/platform/frameworks/base.git/+/master/services/usb/java/com/android/server/usb/UsbUserSettingsManager.java#178

I assumed that as a device owner you have full control over your ROM source code.

edited May 08 '19 at 12:14

answered May 08 '19 at 11:34

Wojciech Sadurski

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9

Unfortunately this is not a custom ROM and I don't have root access. The device owner app is set using standard [provisioning methods](https://developers.google.com/android/management/provision-device). Therefore I cannot use any of these solutions. – sdabet May 09 '19 at 18:48
Maybe your device owner app could declare the appropriate intent filter and react to plugging in of the USB device by calling grantDevicePermission() on UsbManager for a uid of the third party app which it can get in some other way? The idea is similar to what is done in onDestroy() here: https://android.googlesource.com/platform/frameworks/base/+/android-7.0.0_r1/packages/SystemUI/src/com/android/systemui/usb/UsbPermissionActivity.java – Wojciech Sadurski May 10 '19 at 08:55
I've just tried it, but unfortunately the [UsbManager.grantPermission()](https://android.googlesource.com/platform/frameworks/base/+/master/core/java/android/hardware/usb/UsbManager.java#601) methods require the [MANAGE_USB](https://github.com/aosp-mirror/platform_frameworks_base/blob/master/core/res/AndroidManifest.xml#L1700) permission which is only granted to system & privileged app, but not device owner apps. – sdabet May 10 '19 at 19:03
Did you manage to find any way to do it without OS source code ? – Андрій Пугач Oct 16 '19 at 19:02
Did anyone find an adb prop to toggle this config parameter? It looks like it is built in at build time and not exposed through ADB. – dazza5000 Nov 15 '19 at 00:45

score 0 · Answer 2 · answered Dec 22 '20 at 09:40

0

It's a bit old, but hopefully it helps s.o. else. I've been using this for granting permission to apps

public boolean setPermissionGrantState (ComponentName admin, 
                String packageName, 
                String permission, 
                int grantState)

Link: https://developer.android.com/reference/android/app/admin/DevicePolicyManager#setPermissionGrantState(android.content.ComponentName,%20java.lang.String,%20java.lang.String,%20int)

answered Dec 22 '20 at 09:40

Chinh Nguyen

583
1
7
14

1

AFAIK that doesn't work with USB permissions (I already mentioned this method in my question) – sdabet Dec 22 '20 at 14:37

Grant USB permissions as device owner

2 Answers2