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Date:   Wed, 19 Jul 2023 19:23:37 +0000
To:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>
From:   =?utf-8?Q?Barnab=C3=A1s_P=C5=91cze?= <pobrn@protonmail.com>
Cc:     linux-kernel@vger.kernel.org, platform-driver-x86@vger.kernel.org,
        Mark Gross <markgross@kernel.org>,
        Hans de Goede <hdegoede@redhat.com>,
        Armin Wolf <W_Armin@gmx.de>
Subject: Re: [RFC PATCH v1] platform/x86: wmi: Do not register driver with invalid GUID
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Hi


2023. j=C3=BAlius 17., h=C3=A9tf=C5=91 13:31 keltez=C3=A9ssel, Andy Shevche=
nko =C3=ADrta:

> On Mon, Jul 17, 2023 at 11:23:50AM +0000, Barnab=C3=A1s P=C5=91cze wrote:
> > 2023. j=C3=BAlius 17., h=C3=A9tf=C5=91 11:49 keltez=C3=A9ssel, Andy She=
vchenko <andriy.shevchenko@linux.intel.com> =C3=ADrta:
> > On Sat, Jul 15, 2023 at 09:24:16PM +0000, Barnab=C3=A1s P=C5=91cze wrot=
e:
> > > > Since a WMI driver's ID table contains strings it is relatively
> > > > easy to make mistakes. At the moment, there is no feedback
> > > > if any of the specified GUIDs are invalid (since
> > > > 028e6e204ace1f080cfeacd72c50397eb8ae8883).
> > > >
> > > > So check if the GUIDs in the driver's ID table are valid,
> > > > print all invalid ones, and refuse to register the driver
> > > > if any of the GUIDs are invalid.
> > >
> > > 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 for=
mat is the same.
>=20
> Then add guid_is_valid() to complete the API. Perhaps with the renaming t=
he
> common part to something else.

But that would be the exact same function. GUIDs are UUIDs, aren't they?


>=20
> > > think we need to validate it here. Why not in file2alias.c?
> > > [...]
> >
> > 1) that seems like a more complicated change (duplicating `uuid_is_vali=
d()`?);
> > 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 fi=
le2alias.c
> > also contains an equivalent/similar check.
>=20
> 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.


Regards,
Barnab=C3=A1s P=C5=91cze