This is a note to let you know that I've just added the patch titled

iio:health:afe4403 Fix timestamp alignment and prevent data leak.

to my staging git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git in the staging-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 3f9c6d38797e9903937b007a341dad0c251765d6 Mon Sep 17 00:00:00 2001

From: Jonathan Cameron Jonathan.Cameron@huawei.com Date: Sun, 17 May 2020 18:29:56 +0100 Subject: iio:health:afe4403 Fix timestamp alignment and prevent data leak.

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 --- drivers/iio/health/afe4403.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/health/afe4403.c b/drivers/iio/health/afe4403.c index e9f87e42ff4f..a3507624b30f 100644 --- a/drivers/iio/health/afe4403.c +++ b/drivers/iio/health/afe4403.c @@ -65,6 +65,7 @@ static const struct reg_field afe4403_reg_fields[] = { * @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; @@ -74,6 +75,8 @@ 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 { @@ -309,7 +312,6 @@ static irqreturn_t afe4403_trigger_handler(int irq, void *private) 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];

@@ -326,7 +328,7 @@ static irqreturn_t afe4403_trigger_handler(int irq, void *private) if (ret) goto err;

- buffer[i++] = get_unaligned_be24(&rx[0]); + afe->buffer[i++] = get_unaligned_be24(&rx[0]); }

/* Disable reading from the device */ @@ -335,7 +337,8 @@ static irqreturn_t afe4403_trigger_handler(int irq, void *private) 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);