[PATCH 1/1] v4l: ioctl: Validate num_planes before using it

[Sakari Ailus <sakari.ailus@linux.intel.com>]

The for loop to reset the memory of the plane reserved fields runs over
num_planes provided by the user without validating it. Ensure num_planes
is no more than VIDEO_MAX_PLANES before the loop.

Fixes: 4e1e0eb0e074 ("media: v4l2-ioctl: Zero v4l2_plane_pix_format reserved fields")
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
Hi folks,

This patch goes on top of Thierry's patch "media: v4l2-ioctl: Clear only
per-plane reserved fields".

 drivers/media/v4l2-core/v4l2-ioctl.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 392f1228af7b5..9e68a608ac6d3 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -1551,6 +1551,8 @@ static int v4l_s_fmt(const struct v4l2_ioctl_ops *ops,
 		if (unlikely(!ops->vidioc_s_fmt_vid_cap_mplane))
 			break;
 		CLEAR_AFTER_FIELD(p, fmt.pix_mp.xfer_func);
+		if (p->fmt.pix_mp.num_planes > VIDEO_MAX_PLANES)
+			break;
 		for (i = 0; i < p->fmt.pix_mp.num_planes; i++)
 			CLEAR_AFTER_FIELD(&p->fmt.pix_mp.plane_fmt[i], bytesperline);
 		return ops->vidioc_s_fmt_vid_cap_mplane(file, fh, arg);
@@ -1581,6 +1583,8 @@ static int v4l_s_fmt(const struct v4l2_ioctl_ops *ops,
 		if (unlikely(!ops->vidioc_s_fmt_vid_out_mplane))
 			break;
 		CLEAR_AFTER_FIELD(p, fmt.pix_mp.xfer_func);
+		if (p->fmt.pix_mp.num_planes > VIDEO_MAX_PLANES)
+			break;
 		for (i = 0; i < p->fmt.pix_mp.num_planes; i++)
 			CLEAR_AFTER_FIELD(&p->fmt.pix_mp.plane_fmt[i], bytesperline);
 		return ops->vidioc_s_fmt_vid_out_mplane(file, fh, arg);
@@ -1648,6 +1652,8 @@ static int v4l_try_fmt(const struct v4l2_ioctl_ops *ops,
 		if (unlikely(!ops->vidioc_try_fmt_vid_cap_mplane))
 			break;
 		CLEAR_AFTER_FIELD(p, fmt.pix_mp.xfer_func);
+		if (p->fmt.pix_mp.num_planes > VIDEO_MAX_PLANES)
+			break;
 		for (i = 0; i < p->fmt.pix_mp.num_planes; i++)
 			CLEAR_AFTER_FIELD(&p->fmt.pix_mp.plane_fmt[i], bytesperline);
 		return ops->vidioc_try_fmt_vid_cap_mplane(file, fh, arg);
@@ -1678,6 +1684,8 @@ static int v4l_try_fmt(const struct v4l2_ioctl_ops *ops,
 		if (unlikely(!ops->vidioc_try_fmt_vid_out_mplane))
 			break;
 		CLEAR_AFTER_FIELD(p, fmt.pix_mp.xfer_func);
+		if (p->fmt.pix_mp.num_planes > VIDEO_MAX_PLANES)
+			break;
 		for (i = 0; i < p->fmt.pix_mp.num_planes; i++)
 			CLEAR_AFTER_FIELD(&p->fmt.pix_mp.plane_fmt[i], bytesperline);
 		return ops->vidioc_try_fmt_vid_out_mplane(file, fh, arg);
-- 
2.11.0