linux-kernel - Re: [RFC PATCH v1] platform/x86: wmi: Do not register driver with invalid GUID

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Date:   Thu, 20 Jul 2023 10:42:29 +0000
From:   Barnabás Pőcze <pobrn@...tonmail.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     linux-kernel@...r.kernel.org, platform-driver-x86@...r.kernel.org,
        Mark Gross <markgross@...nel.org>,
        Hans de Goede <hdegoede@...hat.com>,
        Armin Wolf <W_Armin@....de>
Subject: Re: [RFC PATCH v1] platform/x86: wmi: Do not register driver with invalid GUID

Hi


2023. július 20., csütörtök 10:36 keltezéssel, Andy Shevchenko írta:

> On Wed, Jul 19, 2023 at 07:23:37PM +0000, Barnabás Pőcze wrote:
> > 2023. július 17., hétfő 13:31 keltezéssel, Andy Shevchenko írta:
> > > On Mon, Jul 17, 2023 at 11:23:50AM +0000, Barnabás Pőcze wrote:
> > > > 2023. július 17., hétfő 11:49 keltezéssel, Andy Shevchenko <andriy.shevchenko@...ux.intel.com> írta:
> > > > On Sat, Jul 15, 2023 at 09:24:16PM +0000, Barnabás Pőcze wrote:
> 
> ...
> 
> > > > > Besides using wrong API (uuid_*() vs. guid_*() one), I don't
> > > >
> > > > As far as I can see `guid_parse()` also uses `uuid_is_valid()`, the format is the same.
> > >
> > > Then add guid_is_valid() to complete the API. Perhaps with the renaming the
> > > common part to something else.
> >
> > But that would be the exact same function. GUIDs are UUIDs, aren't they?
> 
> Yes and no. If we want to validate the respective bit for GUID vs. UUID, they
> will be different. Currently they are the same as validation is relaxed in the
> kernel.

I see. Regardless, that is the only check `guid_parse()` does, so I don't think
it is unreasonable to have only that check for the time being.


> 
> > > > > think we need to validate it here. Why not in file2alias.c?
> > > > > [...]
> > > >
> > > > 1) that seems like a more complicated change (duplicating `uuid_is_valid()`?);
> > > > 2) that will only check the GUIDs specified by `MODULE_DEVICE_TABLE()`.
> > > >
> > > > Arguably the second point is not that significant since most users will indeed
> > > > use `MODULE_DEVICE_TABLE()`. But I think the first point has some merit. And
> > > > furthermore, I think this check should be here regardless of whether file2alias.c
> > > > also contains an equivalent/similar check.
> > >
> > > Why do we need it? We never match against wrong GUID from ACPI, since it would
> > > be very weird ACPI table.
> > > [...]
> >
> > The point is to catch typos in drivers' WMI ID tables.
> 
> Yes, that's what file2alias is for. We trust modules we build, right?
> If you don't trust, then we have much bigger problem than this patch
> tries to address.
> [...]

It seems we have to agree to disagree then.


Regards,
Barnabás Pőcze