Re: [PATCH v3 0/5] platform/chrome: Fix a possible UAF via revocable

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Fri, Sep 12, 2025 at 10:30:45AM +0200, Greg KH wrote:
> On Fri, Sep 12, 2025 at 08:17:12AM +0000, Tzung-Bi Shih wrote:
> > This is a follow-up series of [1].  It tries to fix a possible UAF in the
> > fops of cros_ec_chardev after the underlying protocol device has gone by
> > using revocable.
> > 
> > The 1st patch introduces the revocable which is an implementation of ideas
> > from the talk [2].
> > 
> > The 2nd and 3rd patches add test cases for revocable in Kunit and selftest.
> > 
> > The 4th patch converts existing protocol devices to resource providers
> > of cros_ec_device.
> > 
> > The 5th patch converts cros_ec_chardev to a resource consumer of
> > cros_ec_device to fix the UAF.
> > 
> > [1] https://lore.kernel.org/chrome-platform/20250721044456.2736300-6-tzungbi@kernel.org/
> > [2] https://lpc.events/event/17/contributions/1627/
> > 
> > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > Cc: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> > Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
> 
> This is, frankly, wonderful work.  Thanks so much for doing this, it's
> what many of us have been wanting to see for a very long time but none
> of us got around to actually doing it.
> 
> And it has tests!  And documentation!  Couldn't ask for more.
> 
> We can bikeshed about the REVOCABLE() macro name, but frankly, you wrote
> it, you get to pick it :)
> 
> Laurent, Bartosz, Wolfram, any objection to this series?  I think this
> addresses the issues that all of you have been raising for years with
> our access of pointers that have different lifecycles from other
> structures (i.e. struct cdev from struct device).

I'll check this either later today or over the weekend.

> Also, Danilo, if you get the chance, can you give this a review as well?
> At first glance it looks good to me, but as you wrote the Rust
> implementation of this feature, a second pair of eyes would be great to
> have if you have the time.

-- 
Regards,

Laurent Pinchart