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 a 40 byte 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() data with alignment
explicitly requested. This data is allocated with kzalloc so no
data can leak appart from previous readings.
Fixes: 87aec56e27ef ("iio: health: Add driver for the TI AFE4404 heart monitor")
Reported-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Cc: Andrew F. Davis <afd@xxxxxx>
---
drivers/iio/health/afe4404.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/iio/health/afe4404.c b/drivers/iio/health/afe4404.c
index e728bbb21ca8..cebb1fd4d0b1 100644
--- a/drivers/iio/health/afe4404.c
+++ b/drivers/iio/health/afe4404.c
@@ -83,6 +83,7 @@ static const struct reg_field afe4404_reg_fields[] = {
* @regulator: Pointer to the regulator for the IC
* @trig: IIO trigger for this device
* @irq: ADC_RDY line interrupt number
+ * @buffer: Used to construct a scan to push to the iio buffer.
*/
struct afe4404_data {
struct device *dev;
@@ -91,6 +92,7 @@ struct afe4404_data {
struct regulator *regulator;
struct iio_trigger *trig;
int irq;
+ s32 buffer[10] __aligned(8);
};
enum afe4404_chan_id {
@@ -328,17 +330,17 @@ static irqreturn_t afe4404_trigger_handler(int irq, void *private)
struct iio_dev *indio_dev = pf->indio_dev;
struct afe4404_data *afe = iio_priv(indio_dev);
int ret, bit, i = 0;
- s32 buffer[10];
for_each_set_bit(bit, indio_dev->active_scan_mask,
indio_dev->masklength) {
ret = regmap_read(afe->regmap, afe4404_channel_values[bit],
- &buffer[i++]);
+ &afe->buffer[i++]);
if (ret)
goto err;
}
- iio_push_to_buffers_with_timestamp(indio_dev, buffer, pf->timestamp);
+ iio_push_to_buffers_with_timestamp(indio_dev, afe->buffer,
+ pf->timestamp);
err:
iio_trigger_notify_done(indio_dev->trig);
--
2.26.2
