On Thu, 6 Jun 2019 08:59:10 +0000
"Ardelean, Alexandru" <alexandru.Ardelean@xxxxxxxxxx> wrote:
> On Tue, 2019-06-04 at 20:40 +0800, Young Xiao wrote:
> > [External]
> >
> >
> > The incorrect limit for the for_each_set_bit loop was noticed whilst fixing
> > this other case. Note that as we only have 3 possible entries a the moment
> > and the value was set to 4, the bug would not have any effect currently.
> > It will bite fairly soon though, so best fix it now.
> >
> > See commit ef4b4856593f ("iio:core: Fix bug in length of event info_mask and
> > catch unhandled bits set in masks.") for details.
> >
> > Signed-off-by: Young Xiao <92siuyang@xxxxxxxxx>
>
> Reviewed-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
>
> Thanks for this patch.
> This fix is validated also by the fact that iio_device_add_info_mask_type() has this check on the same iteration.
I don't think it is technically a bug, as the higher bits should never be set.
Still it is a sensible bit of hardening so applied to the togreg branch of iio.git
and pushed out as testing.
Thanks
Jonathan
>
>
> > ---
> > drivers/iio/industrialio-core.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> > index f5a4581..dd8873a 100644
> > --- a/drivers/iio/industrialio-core.c
> > +++ b/drivers/iio/industrialio-core.c
> > @@ -1107,6 +1107,8 @@ static int iio_device_add_info_mask_type_avail(struct iio_dev *indio_dev,
> > char *avail_postfix;
> >
> > for_each_set_bit(i, infomask, sizeof(*infomask) * 8) {
> > + if (i >= ARRAY_SIZE(iio_chan_info_postfix))
> > + return -EINVAL;
> > avail_postfix = kasprintf(GFP_KERNEL,
> > "%s_available",
> > iio_chan_info_postfix[i]);
> > --
> > 2.7.4
> >
