From: Jonathan Cameron Jonathan.Cameron@huawei.com
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 lars@metafoo.de Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Acked-by: Andrew F. Davis afd@ti.com Cc: Stable@vger.kernel.org Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- 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);