On Thu, 6 Jan 2022 06:31:55 +0000
"Tanislav, Cosmin" <Cosmin.Tanislav@xxxxxxxxxx> wrote:
> Reviewed-by: Cosmin Tanislav <cosmin.tanislav@xxxxxxxxxx>
>
> Put "iio: addac: ad74413r:" in patch title, maybe?
I can fix that up whilst applying.
I'll pick this up after rc1 is out.
Thanks,
Jonathan
>
> > -----Original Message-----
> > From: Kees Cook <keescook@xxxxxxxxxxxx>
> > Sent: Wednesday, January 5, 2022 8:02 PM
> > To: Lars-Peter Clausen <lars@xxxxxxxxxx>
> > Cc: Kees Cook <keescook@xxxxxxxxxxxx>; Hennerich, Michael
> > <Michael.Hennerich@xxxxxxxxxx>; Tanislav, Cosmin
> > <Cosmin.Tanislav@xxxxxxxxxx>; Jonathan Cameron <jic23@xxxxxxxxxx>;
> > linux-iio@xxxxxxxxxxxxxxx; Linus Walleij <linus.walleij@xxxxxxxxxx>; linux-
> > kernel@xxxxxxxxxxxxxxx; linux-hardening@xxxxxxxxxxxxxxx
> > Subject: [PATCH v2] iio: addac: Do not reference negative array offsets
> >
> > [External]
> >
> > Instead of aiming rx_buf at an invalid array-boundary-crossing location,
> > just skip the first increment. Fixes this warning seen when building
> > with -Warray-bounds:
> >
> > drivers/iio/addac/ad74413r.c: In function 'ad74413r_update_scan_mode':
> > drivers/iio/addac/ad74413r.c:843:22: warning: array subscript -4 is below
> > array bounds of 'u8[16]' { aka 'unsigned char[16]'} [-Warray-bounds]
> > 843 | u8 *rx_buf = &st->adc_samples_buf.rx_buf[-1 *
> > AD74413R_FRAME_SIZE];
> > |
> > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > drivers/iio/addac/ad74413r.c:84:20: note: while referencing 'rx_buf'
> > 84 | u8 rx_buf[AD74413R_FRAME_SIZE *
> > AD74413R_CHANNEL_MAX];
> > | ^~~~~~
> >
> > Cc: Lars-Peter Clausen <lars@xxxxxxxxxx>
> > Cc: Michael Hennerich <Michael.Hennerich@xxxxxxxxxx>
> > Cc: Cosmin Tanislav <cosmin.tanislav@xxxxxxxxxx>
> > Cc: Jonathan Cameron <jic23@xxxxxxxxxx>
> > Cc: linux-iio@xxxxxxxxxxxxxxx
> > Fixes: fea251b6a5db ("iio: addac: add AD74413R driver")
> > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> > ---
> > v1:
> > https://urldefense.com/v3/__https://lore.kernel.org/lkml/20211215232321.
> > 2069314-1-
> > keescook@xxxxxxxxxxxx/__;!!A3Ni8CS0y2Y!vadcwdERjyNVz3vFIp5m5S2ms
> > oFHro8aKzH9ulwPevCKHpev6D53gibZrv5U9mPHGcoB$
> > v2:
> > - use "xfer" for checking "first through the loop"
> > ---
> > drivers/iio/addac/ad74413r.c | 7 ++++---
> > 1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/iio/addac/ad74413r.c b/drivers/iio/addac/ad74413r.c
> > index 5271073bb74e..aba9a643a4ca 100644
> > --- a/drivers/iio/addac/ad74413r.c
> > +++ b/drivers/iio/addac/ad74413r.c
> > @@ -840,7 +840,7 @@ static int ad74413r_update_scan_mode(struct iio_dev
> > *indio_dev,
> > {
> > struct ad74413r_state *st = iio_priv(indio_dev);
> > struct spi_transfer *xfer = st->adc_samples_xfer;
> > - u8 *rx_buf = &st->adc_samples_buf.rx_buf[-1 *
> > AD74413R_FRAME_SIZE];
> > + u8 *rx_buf = st->adc_samples_buf.rx_buf;
> > u8 *tx_buf = st->adc_samples_tx_buf;
> > unsigned int channel;
> > int ret = -EINVAL;
> > @@ -894,9 +894,10 @@ static int ad74413r_update_scan_mode(struct
> > iio_dev *indio_dev,
> >
> > spi_message_add_tail(xfer, &st->adc_samples_msg);
> >
> > - xfer++;
> > tx_buf += AD74413R_FRAME_SIZE;
> > - rx_buf += AD74413R_FRAME_SIZE;
> > + if (xfer != st->adc_samples_xfer)
> > + rx_buf += AD74413R_FRAME_SIZE;
> > + xfer++;
> > }
> >
> > xfer->rx_buf = rx_buf;
> > --
> > 2.30.2
>
