From: Jonathan Cameron <[email protected]>
commit 3f9c6d38797e9903937b007a341dad0c251765d6 upstream.
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 32 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: eec96d1e2d31 ("iio: health: Add driver for the TI AFE4403 heart monitor")
Reported-by: Lars-Peter Clausen <[email protected]>
Signed-off-by: Jonathan Cameron <[email protected]>
Acked-by: Andrew F. Davis <[email protected]>
Cc: <[email protected]>
Signed-off-by: Jonathan Cameron <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/iio/health/afe4403.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
--- a/drivers/iio/health/afe4403.c
+++ b/drivers/iio/health/afe4403.c
@@ -71,6 +71,7 @@ static const struct reg_field afe4403_re
* @regulator: Pointer to the regulator for the IC
* @trig: IIO trigger for this device
* @irq: ADC_RDY line interrupt number
+ * @buffer: Used to construct data layout to push into IIO buffer.
*/
struct afe4403_data {
struct device *dev;
@@ -80,6 +81,8 @@ struct afe4403_data {
struct regulator *regulator;
struct iio_trigger *trig;
int irq;
+ /* Ensure suitable alignment for timestamp */
+ s32 buffer[8] __aligned(8);
};
enum afe4403_chan_id {
@@ -318,7 +321,6 @@ static irqreturn_t afe4403_trigger_handl
struct iio_dev *indio_dev = pf->indio_dev;
struct afe4403_data *afe = iio_priv(indio_dev);
int ret, bit, i = 0;
- s32 buffer[8];
u8 tx[4] = {AFE440X_CONTROL0, 0x0, 0x0, AFE440X_CONTROL0_READ};
u8 rx[3];
@@ -335,9 +337,9 @@ static irqreturn_t afe4403_trigger_handl
if (ret)
goto err;
- buffer[i++] = (rx[0] << 16) |
- (rx[1] << 8) |
- (rx[2]);
+ afe->buffer[i++] = (rx[0] << 16) |
+ (rx[1] << 8) |
+ (rx[2]);
}
/* Disable reading from the device */
@@ -346,7 +348,8 @@ static irqreturn_t afe4403_trigger_handl
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);
