iio:health:afe4403 Fix timestamp alignment and prevent data leak.
authorJonathan Cameron <Jonathan.Cameron@huawei.com>
Sun, 17 May 2020 17:29:56 +0000 (18:29 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 22 Jul 2020 07:34:04 +0000 (09:34 +0200)
commit22893fb0af03596dfdafbbdb78373efcff9c4316
tree7d8a3e61674d08e7a796e55a5846440a0a6c6085
parentb7cf06cc606afafcc5e8423cf3907868c40de822
iio:health:afe4403 Fix timestamp alignment and prevent data leak.

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