How is the PawnIO driver supposedly safer than WinRing0?

[usr97629238]

WinRing0 was flagged by Microsoft not because it is unsafe by itself but because it allows third-party applications unrestricted access to hardware.
PawnIO offers essentially the same functionality.
A genuinely safer alternative would be a 3rd driver that is somehow hardwired to restrict hardware access to ONLY fans/sensors, and NOT PawnIO.

[Rem0o]

It's safer because it doesn't have the same elevation exploit as WinRing0, and it is not an open-bar type of driver.

A genuinely safer alternative would be a 3rd driver that is somehow hardwired to restrict hardware access to ONLY fans/sensors, and NOT PawnIO.

PawnIO already kind of do this, as it loads small modules with restricted surface.

Great write-up on the subject here: LibreHardwareMonitor/LibreHardwareMonitor#984 (comment)

[usr97629238]

Thanks for the link.

But I'm still not that comfortable with having the "full" PawnIO driver installed (which, to quote namazso, is "provided with even more powerful and dangerous natives than WinRing0 originally did" and the only safeguard is that only namazso has the keys).

Here is a scenario:

• namazso is personally hacked and the keys are leaked or an exploit is found in PawnIO that allows overriding that,
• a bad actor writes whatever rootkit PawnIO sub-scripts they want,
• all the PCs that have seemingly ultra harmless apps like Fan Control (or anything else that relies on PawnIO) are now on borrowed time.

Vs. having a driver, probably PawnIO based, but tailored specifically for Fan Control - that is hardwired to provide only the barest minimum needed to read/set fans/temps.

[Rem0o]

I invite you to discuss this in the LHM thread. In the end I totally rely on that library, as I don't want to manage a closed-source backend for sensor detection by myself. I just don't have the time, will or resources to do so. I can provide my feedback, but I kinda have to go-along and deal with what we have available to us in the end.

[usr97629238]

Have you looked into https://www.ocbase.com/news/oring-update-april-2025?
Not sure if their approach is any better or more secure though as they don't say much.

[namazso]

I contacted them back when they announced this as I'm also interested what kind of limitation they can come up with, because I failed to make one any simpler than a Turing complete interpreter. If it's more restrictive than PawnIO (ie needs more involvement to add and ship device support) then it will be up to anyone which one to choose. If it's less restrictive, I'll be more than happy to add it as a backend for a PawnIO-compatible user-mode Pawn interpreter.

[usr97629238]

So, have they ever answered? Any progress since April?

[Rem0o]

It's a bundled modular driver with limited functionality per project. You basically send them the inventory of functionality you want, and they package it as such to restrict it to only those functions. They then send a signed version of that specific subset.

I've talked to Adrien and that's basically how it works. I will experiment with a simple version of it to see what integration would look like. In a few weeks probably.