Re: [PATCH v1] HID: make arrays usage and value to be the same

[Will McVicker]

Great! Thanks for the reply.

--Will

On Thu, Dec 17, 2020 at 2:19 AM Jiri Kosina <jikos@xxxxxxxxxx> wrote:
>
> On Mon, 14 Dec 2020, Will McVicker wrote:
>
> > > The HID subsystem allows an "HID report field" to have a different
> > > number of "values" and "usages" when it is allocated. When a field
> > > struct is created, the size of the usage array is guaranteed to be at
> > > least as large as the values array, but it may be larger. This leads to
> > > a potential out-of-bounds write in
> > > __hidinput_change_resolution_multipliers() and an out-of-bounds read in
> > > hidinput_count_leds().
> > >
> > > To fix this, let's make sure that both the usage and value arrays are
> > > the same size.
> > >
> > > Signed-off-by: Will McVicker <willmcvicker@xxxxxxxxxx>
> > > ---
> > >  drivers/hid/hid-core.c | 6 +++---
> > >  1 file changed, 3 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> > > index 56172fe6995c..8a8b2b982f83 100644
> > > --- a/drivers/hid/hid-core.c
> > > +++ b/drivers/hid/hid-core.c
> > > @@ -90,7 +90,7 @@ EXPORT_SYMBOL_GPL(hid_register_report);
> > >   * Register a new field for this report.
> > >   */
> > >
> > > -static struct hid_field *hid_register_field(struct hid_report *report, unsigned usages, unsigned values)
> > > +static struct hid_field *hid_register_field(struct hid_report *report, unsigned usages)
> > >  {
> > >     struct hid_field *field;
> > >
> > > @@ -101,7 +101,7 @@ static struct hid_field *hid_register_field(struct hid_report *report, unsigned
> > >
> > >     field = kzalloc((sizeof(struct hid_field) +
> > >                      usages * sizeof(struct hid_usage) +
> > > -                    values * sizeof(unsigned)), GFP_KERNEL);
> > > +                    usages * sizeof(unsigned)), GFP_KERNEL);
> > >     if (!field)
> > >             return NULL;
> > >
> > > @@ -300,7 +300,7 @@ static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsign
> > >     usages = max_t(unsigned, parser->local.usage_index,
> > >                              parser->global.report_count);
> > >
> > > -   field = hid_register_field(report, usages, parser->global.report_count);
> > > +   field = hid_register_field(report, usages);
> > >     if (!field)
> > >             return 0;
> > >
> > > --
> > > 2.29.2.576.ga3fc446d84-goog
> > >
> >
> > Hi Jiri and Benjamin,
> >
> > This is a friendly reminder in case this got lost in your inbox.
>
> Hi Will,
>
> I am planning to merge it once the merge window is over.
>
> --
> Jiri Kosina
> SUSE Labs
>