From: Jonathan Cameron Jonathan.Cameron@huawei.com
commit ea5e7a7bb6205d24371373cd80325db1bc15eded 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 structure in the iio_priv() data. This data is allocated with kzalloc so no data can leak apart from previous readings.
Fixes: 16bf793f86b2 ("iio: humidity: hdc100x: add triggered buffer support for HDC100X") Reported-by: Lars-Peter Clausen lars@metafoo.de Acked-by: Matt Ranostay matt.ranostay@konsulko.com Cc: Alison Schofield amsfield22@gmail.com Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Cc: Stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/iio/humidity/hdc100x.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
--- a/drivers/iio/humidity/hdc100x.c +++ b/drivers/iio/humidity/hdc100x.c @@ -38,6 +38,11 @@ struct hdc100x_data {
/* integration time of the sensor */ int adc_int_us[2]; + /* Ensure natural alignment of timestamp */ + struct { + __be16 channels[2]; + s64 ts __aligned(8); + } scan; };
/* integration time in us */ @@ -319,7 +324,6 @@ static irqreturn_t hdc100x_trigger_handl struct i2c_client *client = data->client; int delay = data->adc_int_us[0] + data->adc_int_us[1]; int ret; - s16 buf[8]; /* 2x s16 + padding + 8 byte timestamp */
/* dual read starts at temp register */ mutex_lock(&data->lock); @@ -330,13 +334,13 @@ static irqreturn_t hdc100x_trigger_handl } usleep_range(delay, delay + 1000);
- ret = i2c_master_recv(client, (u8 *)buf, 4); + ret = i2c_master_recv(client, (u8 *)data->scan.channels, 4); if (ret < 0) { dev_err(&client->dev, "cannot read sensor data\n"); goto err; }
- iio_push_to_buffers_with_timestamp(indio_dev, buf, + iio_push_to_buffers_with_timestamp(indio_dev, &data->scan, iio_get_time_ns(indio_dev)); err: mutex_unlock(&data->lock);