[PATCH 1/2] media: mali-c55: Check the parameters buffer address before copying

[David Carlier <devnexen@gmail.com>]

mali_c55_params_buf_prepare() copies the parameters buffer supplied by
userspace into the driver's scratch buffer, using the result of
vb2_plane_vaddr() as the source without checking it. The queue accepts
VB2_DMABUF, and vb2_dc_vaddr() returns NULL for an exporter that cannot
be vmapped, so the memcpy() dereferences NULL.

Reject the buffer at prepare time instead.

Fixes: d5f281f3dd29 ("media: mali-c55: Add Mali-C55 ISP driver")
Cc: stable@vger.kernel.org
Signed-off-by: David Carlier <devnexen@gmail.com>
---
 drivers/media/platform/arm/mali-c55/mali-c55-params.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/media/platform/arm/mali-c55/mali-c55-params.c b/drivers/media/platform/arm/mali-c55/mali-c55-params.c
index 70106276b7e4..16e895e3488e 100644
--- a/drivers/media/platform/arm/mali-c55/mali-c55-params.c
+++ b/drivers/media/platform/arm/mali-c55/mali-c55-params.c
@@ -710,6 +710,9 @@ static int mali_c55_params_buf_prepare(struct vb2_buffer *vb)
 	struct mali_c55 *mali_c55 = params->mali_c55;
 	int ret;
 
+	if (!config)
+		return -EFAULT;
+
 	ret = v4l2_isp_params_validate_buffer_size(mali_c55->dev, vb,
 			v4l2_isp_buffer_size(MALI_C55_PARAMS_MAX_SIZE));
 	if (ret)
-- 
2.55.0