[PATCH 6.6 020/396] media: nxp: imx8-isi: Check whether crossbar pad is non-NULL before access

Greg Kroah-Hartman
2024-04-01T16:35:43Z

From: Marek Vasut <marex@denx.de>

[ Upstream commit eb2f932100288dbb881eadfed02e1459c6b9504c ]

When translating source to sink streams in the crossbar subdev, the
driver tries to locate the remote subdev connected to the sink pad. The
remote pad may be NULL, if userspace tries to enable a stream that ends
at an unconnected crossbar sink. When that occurs, the driver
dereferences the NULL pad, leading to a crash.

Prevent the crash by checking if the pad is NULL before using it, and
return an error if it is.

Cc: stable@vger.kernel.org # 6.1
Fixes: cf21f328fcaf ("media: nxp: Add i.MX8 ISI driver")
Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/20231201150614.63300-1-marex@denx.de
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/media/platform/nxp/imx8-isi/imx8-isi-crossbar.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/nxp/imx8-isi/imx8-isi-crossbar.c b/drivers/media/platform/nxp/imx8-isi/imx8-isi-crossbar.c
index 792f031e032ae..44354931cf8a1 100644
--- a/drivers/media/platform/nxp/imx8-isi/imx8-isi-crossbar.c
+++ b/drivers/media/platform/nxp/imx8-isi/imx8-isi-crossbar.c
@@ -160,8 +160,14 @@ mxc_isi_crossbar_xlate_streams(struct mxc_isi_crossbar *xbar,
}

pad = media_pad_remote_pad_first(&xbar->pads[sink_pad]);
- sd = media_entity_to_v4l2_subdev(pad->entity);
+ if (!pad) {
+ dev_dbg(xbar->isi->dev,
+ "no pad connected to crossbar input %u\n",
+ sink_pad);
+ return ERR_PTR(-EPIPE);
+ }

+ sd = media_entity_to_v4l2_subdev(pad->entity);
if (!sd) {
dev_dbg(xbar->isi->dev,
"no entity connected to crossbar input %u\n",
--
2.43.0