From: Lars-Peter Clausen <lars@metafoo.de>
To: jic23@kernel.org, linux-iio@vger.kernel.org
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>,
Peter Meerwald <pmeerw@pmeerw.net>
Subject: Re: [PATCH 02/11] iio:accel:mma8452: Fix timestamp alignment and prevent data leak.
Date: Sun, 17 May 2020 20:57:26 +0200 [thread overview]
Message-ID: <170d718b-7ee4-ac08-c083-830c06c59f65@metafoo.de> (raw)
In-Reply-To: <20200517173000.220819-3-jic23@kernel.org>
On 5/17/20 7:29 PM, jic23@kernel.org wrote:
> From: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>
> 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 16 byte u8 array 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
> ensured by use of an explicit c structure. This data is allocated
> with kzalloc so no data can leak appart from previous readings.
>
> Fixes: c7eeea93ac60 ("iio: Add Freescale MMA8452Q 3-axis accelerometer driver")
> Reported-by: Lars-Peter Clausen <lars@metafoo.de>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Cc: Peter Meerwald <pmeerw@pmeerw.net>
> ---
> drivers/iio/accel/mma8452.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
> index 00e100fc845a..704867ffda7a 100644
> --- a/drivers/iio/accel/mma8452.c
> +++ b/drivers/iio/accel/mma8452.c
> @@ -110,6 +110,12 @@ struct mma8452_data {
> int sleep_val;
> struct regulator *vdd_reg;
> struct regulator *vddio_reg;
> +
> + /* Ensure correct alignment of time stamp when present */
> + struct {
> + __be16 channels[3];
> + s64 ts;
> + } buffer;
I feel we should have a macro for this.
DECLARE_IIO_BUFFER_WITH_TIMESTAMP(buffer, __be16, 3);
The name is maybe a bit too long.
And potentially also DECLARE_IIO_BUFFER_WITH_TIMESTAMP_ON_STACK() which
initializes it to zero.
> };
>
> /**
> @@ -1091,14 +1097,13 @@ static irqreturn_t mma8452_trigger_handler(int irq, void *p)
> struct iio_poll_func *pf = p;
> struct iio_dev *indio_dev = pf->indio_dev;
> struct mma8452_data *data = iio_priv(indio_dev);
> - u8 buffer[16]; /* 3 16-bit channels + padding + ts */
> int ret;
>
> - ret = mma8452_read(data, (__be16 *)buffer);
> + ret = mma8452_read(data, data->buffer.channels);
> if (ret < 0)
> goto done;
>
> - iio_push_to_buffers_with_timestamp(indio_dev, buffer,
> + iio_push_to_buffers_with_timestamp(indio_dev, &data->buffer,
> iio_get_time_ns(indio_dev));
>
> done:
next prev parent reply other threads:[~2020-05-17 18:57 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-17 17:29 [PATCH 00/11] IIO: 1st set of timestamp alignment fixes jic23
2020-05-17 17:29 ` [PATCH 01/11] iio: accel: kxsd9: Fix alignment of local buffer jic23
2020-05-17 17:29 ` [PATCH 02/11] iio:accel:mma8452: Fix timestamp alignment and prevent data leak jic23
2020-05-17 18:57 ` Lars-Peter Clausen [this message]
2020-05-18 16:37 ` Jonathan Cameron
2020-05-17 17:29 ` [PATCH 03/11] iio:accel:bmc150-accel: " jic23
2020-05-17 17:29 ` [PATCH 04/11] iio:accel:mma7455: " jic23
2020-05-17 17:29 ` [PATCH 05/11] iio:gyro:itg3200: " jic23
2020-05-17 17:29 ` [PATCH 06/11] iio:proximity:mb1232: " jic23
2020-05-17 17:29 ` [PATCH 07/11] iio:health:afe4403 " jic23
2020-05-18 0:09 ` Andrew F. Davis
2020-05-18 16:06 ` Jonathan Cameron
2020-05-21 13:11 ` Andrew F. Davis
2020-05-21 14:44 ` Jonathan Cameron
2020-05-21 18:45 ` Jonathan Cameron
2020-05-21 19:05 ` Andrew F. Davis
2020-05-24 15:33 ` Jonathan Cameron
2020-05-17 17:29 ` [PATCH 08/11] iio:health:afe4404 " jic23
2020-05-24 15:34 ` Jonathan Cameron
2020-05-17 17:29 ` [PATCH 09/11] iio:chemical:ccs811: " jic23
2020-05-17 17:29 ` [PATCH 10/11] iio:chemical:sps30: Fix timestamp alignment jic23
2020-05-17 19:07 ` Tomasz Duszynski
2020-05-21 18:43 ` Jonathan Cameron
2020-05-17 17:30 ` [PATCH 11/11] iio:chemical:pms7003: Fix timestamp alignment and prevent data leak jic23
2020-05-17 19:06 ` Tomasz Duszynski
2020-05-21 18:44 ` Jonathan Cameron
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