Detect host OS based on USB fingerprint

[KapJI]

Description

Feature to detect host OS using wLength field from getDescriptor USB packets.

Context: https://www.reddit.com/r/olkb/comments/x1ezbg/way_to_detect_host_os_in_qmk/

I'd appreciate if someone can write better documentation, I added only some very basic description.

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout/userspace (addition or update)
• Documentation

Checklist

• My code follows the code style of this project: C, Python
• I have read the PR Checklist document and have made the appropriate changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).

[drashna]

There are a few areas that this won't compile, and I've flagged those.

[drashna]

Should be noted that this is originally from keyboardio's arduino module:
https://github.com/keyboardio/FingerprintUSBHost

It's licensed under the MIT License and should probably retain that licensing.

Also, should be noted that there hasn't been any changes to the code since Aug 2018.

Also tagging @algernon.

[algernon]

We haven't done much with the FingerprintUSBHost module in a looong time. As far as I remember, it was more of a proof of concept, rather than a fully fleshed out solution. It's mostly @obra's work, by the way. If there are any licensing questions, he's the right person to ask.

I'm happy to chime in and answer what I can, but my memories of that module are kinda hazy by now.

[obra]

 The short version is that it’s a really cool party trick, but very unreliable in the face of things like virtualization and OS revisions. After testing pretty extensively, I’d not want to use the technique as part of a shipping product. On Sep 24, 2022, at 3:16 PM, Gergely Nagy ***@***.***> wrote: We haven't done much with the FingerprintUSBHost module in a looong time. As far as I remember, it was more of a proof of concept, rather than a fully fleshed out solution. It's mostly @obra's work, by the way. If there are any licensing questions, he's the right person to ask. I'm happy to chime in and answer what I can, but my memories of that module are kinda hazy by now. —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you were mentioned.Message ID: ***@***.***>

[drashna]

Thanks for the feedback! And yeah, the detection is very ... fragile, at best.

[KapJI]

Please note that I have used none of the FingerprintUSBHost code. Only the general idea of using wLength field. All detection heuristics are brand new.

I believe it should be reliable enough to cover most real life cases. I have tried using KVM switch but haven't tried passing device to virtualized host. With more collected data it should be easy to support more less popular cases, I added debugging section specifically for this.

[PeterHindes]

Btw this is mis-recognizing an M1 Max studio as an iOS device (only tested on Ventura).

[tzarc]

Btw this is mis-recognizing an M1 Max studio as an iOS device (only tested on Ventura).

Thus the initial reluctance including it -- it's fragile.
If you want to do some more digging and extend it further, great -- a PR would be lovely.

[KapJI]

I guess it's impossible to distinguish ARM Macs from iOS/iPadOS devices as they use the same USB stack. So OS_IOS is better called something like OS_APPLE_ARM and OS_MACOS is OS_APPLE_INTEL.

[tzarc]

It could be OS version specific, too.
As documented it's "best guess", nothing more.

[PeterHindes]

I will check with my Ventura Intel MacBook. I might make a pr if I have time.

[fauxpark]

It's already been merged.