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

[Will McVicker]

On Mon, Dec 07, 2020 at 07:24:16PM +0100, Greg KH wrote:
> On Mon, Dec 07, 2020 at 09:55:48AM -0800, Will McVicker wrote:
> > On Sat, Dec 05, 2020 at 09:59:57AM +0100, Greg KH wrote:
> > > On Sat, Dec 05, 2020 at 12:48:48AM +0000, 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>
> > > 
> > > Any reason not to also add a cc: stable on this?
> > No reason not to include stable. CC'd here.
> > 
> > > 
> > > And, has this always been the case, or was this caused by some specific
> > > commit in the past?  If so, a "Fixes:" tag is always nice to included.
> > I dug into the history and it's been like this for the past 10 years. So yeah
> > pretty much always like this.
> > 
> > > 
> > > And finally, as you have a fix for this already, no need to cc:
> > > security@k.o as there's nothing the people there can do about it now :)
> > Is that short for security@xxxxxxxxxx? If yes, then I did include them. If no,
> > do you mind explaining?
> 
> Yes, I see you included it, my point was that once you have a patch,
> there is no need to include this email address as all we do at this
> address is work to match up a problem with a developer that can create a
> fix.  You already did this, so no need for us to get involved at all! :)
> 
> thanks,
> 
> greg k-h
Ah okay, thanks for the explanation!

--Will