USBGuard in sys-usb breaks USB device attach

[DemiMarie]

Qubes OS version Qubes release 4.0 (R4.0)

Affected component(s) or functionality USB pass-through

Brief summary If I run USBGuard in sys-usb and block USB devices by default, I cannot attach a USB device to another qube. Allowing the USB device in USBGuard doesn’t help.

How Reproducible 100%

To Reproduce

Steps to reproduce the behavior:

1. Install USBGuard in the template for sys-usb.
2. Add usbcore.authorized_default=0 to the sys-usb kernel command line.
3. Reboot sys-usb.
4. Attach a USB device from sys-usb to another qube.

Expected behavior The attach succeeds, and the device can be used.

Actual behavior The attach succeeds, but the device (a camera in this case) is not usable. It is correctly detected by the frontend qube, but I can’t record video with it.

Screenshots N/A

Additional context

Solutions you've tried

• Reloading the usbip_host kernel module
• Using the device in sys-usb before attaching it to the other qube.

Relevant documentation you've consulted

Related, non-duplicate issues

[marmarek]

Does manually authorizing the device (after connecting via qvm-usb) help?

[DemiMarie]

Manual authorization before connection does not help.

[github-actions[bot]]

This issue is being closed because:

• This issue is on the "Release 4.0 updates" milestone.
• Qubes OS 4.0 reached EOL (end-of-life) over one year ago.
• There has not been any activity on this issue in over one year.

If anyone believes that this issue should be reopened and reassigned to an active milestone, please leave a brief comment. (For example, if a bug still affects Qubes OS 4.1, then the comment "Affects 4.1" will suffice.)