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

From: Jiri Kosina <jikos@kernel.org>
To: Will McVicker <willmcvicker@google.com>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>,
	security@kernel.org, linux-input@vger.kernel.org,
	linux-kernel@vger.kernel.org, kernel-team@android.com,
	Will Coster <willcoster@google.com>,
	stable@vger.kernel.org
Subject: Re: [PATCH v1] HID: make arrays usage and value to be the same
Date: Thu, 17 Dec 2020 11:19:49 +0100 (CET)	[thread overview]
Message-ID: <nycvar.YFH.7.76.2012171119240.25826@cbobk.fhfr.pm> (raw)
In-Reply-To: <X9e5vl+nw4GQNYEw@google.com>

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@google.com>
> > ---
> >  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