From: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
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@xxxxxxxxxx>
Acked-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
---
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:
--
2.26.2
