Re: [PATCH 2/2] HID: picolcd: sanity check report size in raw_event() callback

From: Jiri Kosina
Date: Wed Aug 27 2014 - 04:26:04 EST


On Wed, 27 Aug 2014, Bruno PrÃmont wrote:

> > The report passed to us from transport driver could potentially be
> > arbitrarily large, therefore we better sanity-check it so that raw_data
> > that we hold in picolcd_pending structure are always kept within proper
> > bounds.
> >
> > Cc: stable@xxxxxxxxxxxxxxx
> > Reported-by: Steven Vittitoe <scvitti@xxxxxxxxxx>
> > Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
>
> Acked-by: Bruno PrÃmont <bonbons@xxxxxxxxxxxxxxxxx>

Thanks.

> > ---
> > drivers/hid/hid-picolcd_core.c | 6 ++++++
> > 1 file changed, 6 insertions(+)
> >
> > diff --git a/drivers/hid/hid-picolcd_core.c b/drivers/hid/hid-picolcd_core.c
> > index acbb0210..020df3c 100644
> > --- a/drivers/hid/hid-picolcd_core.c
> > +++ b/drivers/hid/hid-picolcd_core.c
> > @@ -350,6 +350,12 @@ static int picolcd_raw_event(struct hid_device *hdev,
> > if (!data)
> > return 1;
> >
> > + if (size > 64) {
> > + hid_warn(hdev, "invalid size value (%d) for picolcd raw event\n",
> > + size);
>
> Is it worth adding report->id to this hid_warn()?
>
> A valid device is not expected to ever send >64 bytes reports but in
> case a firmware update would do so it would help to know for which
> report it was.

It definitely wouldn't hurt. Pull request with the original patch is now
on its way to Linus though, so let's do this as a followup patch on top
once this is merged.

--
Jiri Kosina
SUSE Labs
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