| Message ID | 20200607155408.958437-12-jic23@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | IIO: Fused set 1 and 2 of timestamp alignment fixes | expand |
On Sun, 7 Jun 2020 16:53:47 +0100 Jonathan Cameron <jic23@kernel.org> wrote: > From: Jonathan Cameron <Jonathan.Cameron@huawei.com> > > One of a class of bugs pointed out by Lars in a recent review. > iio_push_to_buffers_with_timestamp assumes the buffer used is aligned > to the size of the timestamp (8 bytes). This is not guaranteed in > this driver which uses an array of smaller elements on the stack. > As Lars also noted this anti pattern can involve a leak of data to > userspace and that indeed can happen here. We close both issues by > moving to a suitable structure in the iio_priv() > > This data is allocated with kzalloc so no data can leak apart > from previous readings. > > Fixes: 3025c8688c1e ("iio: light: add support for UVIS25 sensor") > Reported-by: Lars-Peter Clausen <lars@metafoo.de> > Acked-by: Lorenzo Bianconi <lorenzo@kernel.org> > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Applied to the fixes-togreg branch of iio.git and marked for stable. I'm going to pick up all the ones in this series that I have had an Ack for. Thanks, Jonathan > --- > drivers/iio/light/st_uvis25.h | 5 +++++ > drivers/iio/light/st_uvis25_core.c | 6 +++--- > 2 files changed, 8 insertions(+), 3 deletions(-) > > diff --git a/drivers/iio/light/st_uvis25.h b/drivers/iio/light/st_uvis25.h > index 78bc56aad129..283086887caf 100644 > --- a/drivers/iio/light/st_uvis25.h > +++ b/drivers/iio/light/st_uvis25.h > @@ -27,6 +27,11 @@ struct st_uvis25_hw { > struct iio_trigger *trig; > bool enabled; > int irq; > + /* Ensure timestamp is naturally aligned */ > + struct { > + u8 chan; > + s64 ts __aligned(8); > + } scan; > }; > > extern const struct dev_pm_ops st_uvis25_pm_ops; > diff --git a/drivers/iio/light/st_uvis25_core.c b/drivers/iio/light/st_uvis25_core.c > index 4d001d50e775..818b8faea73c 100644 > --- a/drivers/iio/light/st_uvis25_core.c > +++ b/drivers/iio/light/st_uvis25_core.c > @@ -234,17 +234,17 @@ static const struct iio_buffer_setup_ops st_uvis25_buffer_ops = { > > static irqreturn_t st_uvis25_buffer_handler_thread(int irq, void *p) > { > - u8 buffer[ALIGN(sizeof(u8), sizeof(s64)) + sizeof(s64)]; > struct iio_poll_func *pf = p; > struct iio_dev *iio_dev = pf->indio_dev; > struct st_uvis25_hw *hw = iio_priv(iio_dev); > int err; > > - err = regmap_read(hw->regmap, ST_UVIS25_REG_OUT_ADDR, (int *)buffer); > + err = regmap_read(hw->regmap, ST_UVIS25_REG_OUT_ADDR, > + (unsigned int *)&hw->scan.chan); > if (err < 0) > goto out; > > - iio_push_to_buffers_with_timestamp(iio_dev, buffer, > + iio_push_to_buffers_with_timestamp(iio_dev, &hw->scan, > iio_get_time_ns(iio_dev)); > > out:
On Sun, Jun 7, 2020 at 6:57 PM Jonathan Cameron <jic23@kernel.org> wrote: ... > + /* Ensure timestamp is naturally aligned */ > + struct { > + u8 chan; > + s64 ts __aligned(8); > + } scan; > }; ... > - err = regmap_read(hw->regmap, ST_UVIS25_REG_OUT_ADDR, (int *)buffer); > + err = regmap_read(hw->regmap, ST_UVIS25_REG_OUT_ADDR, > + (unsigned int *)&hw->scan.chan); Despite knowing that this is okay, from a language perspective this casting is not good. Potential mine for all kinds of static analyzers. I think it should use a temporary unsigned int (or what regmap API wants) variable.
On Sun, 5 Jul 2020 15:05:49 +0300 Andy Shevchenko <andy.shevchenko@gmail.com> wrote: > On Sun, Jun 7, 2020 at 6:57 PM Jonathan Cameron <jic23@kernel.org> wrote: > > ... > > > + /* Ensure timestamp is naturally aligned */ > > + struct { > > + u8 chan; > > + s64 ts __aligned(8); > > + } scan; > > }; > > ... > > > - err = regmap_read(hw->regmap, ST_UVIS25_REG_OUT_ADDR, (int *)buffer); > > + err = regmap_read(hw->regmap, ST_UVIS25_REG_OUT_ADDR, > > + (unsigned int *)&hw->scan.chan); > > Despite knowing that this is okay, from a language perspective this > casting is not good. Potential mine for all kinds of static analyzers. > > I think it should use a temporary unsigned int (or what regmap API > wants) variable. > Good point. Dropped for now. Will revisit. Thanks, Jonathan
diff --git a/drivers/iio/light/st_uvis25.h b/drivers/iio/light/st_uvis25.h index 78bc56aad129..283086887caf 100644 --- a/drivers/iio/light/st_uvis25.h +++ b/drivers/iio/light/st_uvis25.h @@ -27,6 +27,11 @@ struct st_uvis25_hw { struct iio_trigger *trig; bool enabled; int irq; + /* Ensure timestamp is naturally aligned */ + struct { + u8 chan; + s64 ts __aligned(8); + } scan; }; extern const struct dev_pm_ops st_uvis25_pm_ops; diff --git a/drivers/iio/light/st_uvis25_core.c b/drivers/iio/light/st_uvis25_core.c index 4d001d50e775..818b8faea73c 100644 --- a/drivers/iio/light/st_uvis25_core.c +++ b/drivers/iio/light/st_uvis25_core.c @@ -234,17 +234,17 @@ static const struct iio_buffer_setup_ops st_uvis25_buffer_ops = { static irqreturn_t st_uvis25_buffer_handler_thread(int irq, void *p) { - u8 buffer[ALIGN(sizeof(u8), sizeof(s64)) + sizeof(s64)]; struct iio_poll_func *pf = p; struct iio_dev *iio_dev = pf->indio_dev; struct st_uvis25_hw *hw = iio_priv(iio_dev); int err; - err = regmap_read(hw->regmap, ST_UVIS25_REG_OUT_ADDR, (int *)buffer); + err = regmap_read(hw->regmap, ST_UVIS25_REG_OUT_ADDR, + (unsigned int *)&hw->scan.chan); if (err < 0) goto out; - iio_push_to_buffers_with_timestamp(iio_dev, buffer, + iio_push_to_buffers_with_timestamp(iio_dev, &hw->scan, iio_get_time_ns(iio_dev)); out: