I have just updated to Qubes 4.3.
When I plug an external USB drive into the laptop, it no longer shows up in the file browser in sys-usb to access its contents, as I was with Qubes 4.2
The only way I seem to be able to access is to connect it to an AppVM
sys-usb is using Fedora 43 XFCE template but I have also tried debian 13 xfce
Is this how 4.3 is supposed to behave?
Is the right usb controller assigned to sys-usb?
What does lsusb and lsblk have to say?
How about running a mount command inside sys-usb?
Yes.
thank you! interesting design choice.
There is another possible view of this change…
If devices claiming to be disk or storage are attached to sys-usb and drivers are installed, then there is an increase of risk that sys-usb gets owned by an attacker who can provide you with a usb device, or who can exploit some weakness of sys-usb USB stack. Then, all your USB is belong to the bad guy.
I cannot say how big this risk is, but I think it is not zero, except if you only use 100.00000% trusted USB storage devices, and only connect them to equally trusted external computers.
Better to only attach to a disposable qube, and let that get owned.
At least, that is my way to see things - an enhancement, not an annoyance!
Even when sys-usb is default disposable now when you install qubes?
Yes, (IMHO), even then, if anything you care about, or anything that could be a vector towards stuff you care about, will be connected to the usb bus in between sys-usb getting owned and it getting restarted.
For me, that’s mouse&keyboard (on one system), removable disks, occasionally a mobile phone… etc.
Without the mouse&keyboard, I could connect only one device at a time, and restart sys-usb at every disconnect… but I’m not quite sure how to automate that, and it would be quite inconvenient. OTOH, I suspect there are folk who work like that - it’s just a bit too much for my threat/risk model.
…at least, that’s how it looks to me.
The more I think about it, the more this seems like a really good question, that probably deserves a bit of documentation… just being disposable does not remove all threats.
(That is, if there is agreement from folk who actually know what they’re talking about!)
Especially with disposables having networking, but even without, they can still do stuff. For ones with real hardware, they can really pose a risk.