From: Jonathan Cameron Jonathan.Cameron@huawei.com
commit 7b6b51234df6cd8b04fe736b0b89c25612d896b8 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 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 array in the iio_priv() data with alignment explicitly requested. This data is allocated with kzalloc() so no data can leak apart from previous readings.
In this driver, depending on which channels are enabled, the timestamp can be in a number of locations. Hence we cannot use a structure to specify the data layout without it being misleading.
Fixes: 77c4ad2d6a9b ("iio: imu: Add initial support for Bosch BMI160") Reported-by: Lars-Peter Clausen lars@metafoo.de Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Reviewed-by: Alexandru Ardelean alexandru.ardelean@analog.com Cc: Daniel Baluta daniel.baluta@gmail.com Cc: Daniel Baluta daniel.baluta@oss.nxp.com Cc: Stable@vger.kernel.org Link: https://lore.kernel.org/r/20200920112742.170751-6-jic23@kernel.org [sudip: adjust context] Signed-off-by: Sudip Mukherjee sudipm.mukherjee@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iio/imu/bmi160/bmi160.h | 7 +++++++ drivers/iio/imu/bmi160/bmi160_core.c | 6 ++---- 2 files changed, 9 insertions(+), 4 deletions(-)
--- a/drivers/iio/imu/bmi160/bmi160.h +++ b/drivers/iio/imu/bmi160/bmi160.h @@ -7,6 +7,13 @@ struct bmi160_data { struct regmap *regmap; struct iio_trigger *trig; + /* + * Ensure natural alignment for timestamp if present. + * Max length needed: 2 * 3 channels + 4 bytes padding + 8 byte ts. + * If fewer channels are enabled, less space may be needed, as + * long as the timestamp is still aligned to 8 bytes. + */ + __le16 buf[12] __aligned(8); };
extern const struct regmap_config bmi160_regmap_config; --- a/drivers/iio/imu/bmi160/bmi160_core.c +++ b/drivers/iio/imu/bmi160/bmi160_core.c @@ -411,8 +411,6 @@ static irqreturn_t bmi160_trigger_handle struct iio_poll_func *pf = p; struct iio_dev *indio_dev = pf->indio_dev; struct bmi160_data *data = iio_priv(indio_dev); - __le16 buf[12]; - /* 2 sens x 3 axis x __le16 + 2 x __le16 pad + 4 x __le16 tstamp */ int i, ret, j = 0, base = BMI160_REG_DATA_MAGN_XOUT_L; __le16 sample;
@@ -422,10 +420,10 @@ static irqreturn_t bmi160_trigger_handle &sample, sizeof(sample)); if (ret) goto done; - buf[j++] = sample; + data->buf[j++] = sample; }
- iio_push_to_buffers_with_timestamp(indio_dev, buf, pf->timestamp); + iio_push_to_buffers_with_timestamp(indio_dev, data->buf, pf->timestamp); done: iio_trigger_notify_done(indio_dev->trig); return IRQ_HANDLED;