[PATCH v2] iio: buffer: Ensure bounce buffer used for unaligned case is zeroed.

[Jonathan Cameron <jic23@kernel.org>]

From: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>

iio_push_to_buffers_with_ts_unaligned() leaks uninitialized heap memory
to userspace if the data passed in is not a multiple of 8 bytes and the
timestamp is enabled. Specify __GFP_ZERO for the devm_krealloc()
to ensure any extra space is cleared.

Fixes: 95ec3fdf2b79 ("iio: core: Introduce iio_push_to_buffers_with_ts_unaligned()")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260529121005.1470-1-kimjinseob88%40gmail.com
Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>
---

v1: https://patchwork.kernel.org/project/linux-iio/patch/20260604084307.640053-1-jic23@kernel.org/

Drop the memset in favour of __GFP_ZERO.  (Andy)
Thanks to Nuno who pointed out there is a self test to ensure this
behaves as expected.

 drivers/iio/industrialio-buffer.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 531fc4ccc15d..4960c8377932 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -2464,7 +2464,8 @@ int iio_push_to_buffers_with_ts_unaligned(struct iio_dev *indio_dev,
 
 		bb = devm_krealloc(&indio_dev->dev,
 				   iio_dev_opaque->bounce_buffer,
-				   indio_dev->scan_bytes, GFP_KERNEL);
+				   indio_dev->scan_bytes,
+				   GFP_KERNEL | __GFP_ZERO);
 		if (!bb)
 			return -ENOMEM;
 		iio_dev_opaque->bounce_buffer = bb;
-- 
2.55.0