[PATCH] media: staging: media: omap4iss: Fix null dereference for iss

[Tanmay Bhushan <007047221b@gmail.com>]

From 7aa39c0d02bddf9cfa14762f115303b79bfa0ae3 Mon Sep 17 00:00:00 2001
From: Tanmay Bhushan <007047221b@gmail.com>
Date: Wed, 28 Dec 2022 21:01:16 +0100
Subject: [PATCH] media: staging: media: omap4iss: Fix null dereference
for iss

media_pad_remote_pad_first returns NULL in some cases but while using
the return value was used without NULL check which will lead to panic
in case of NULL return. iss_pipeline_is_last returns value check so
have returned 0 in case of NULL and csi2_configure is not documented
for such cases so returned EINVAL for it. Code is not tested
as it is only for NULL dereference verification.

Signed-off-by: Tanmay Bhushan <007047221b@gmail.com>
---
 drivers/staging/media/omap4iss/iss.c      | 6 +++++-
 drivers/staging/media/omap4iss/iss_csi2.c | 4 ++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/media/omap4iss/iss.c
b/drivers/staging/media/omap4iss/iss.c
index fa2a36d829d3..3f01eeff40e7 100644
--- a/drivers/staging/media/omap4iss/iss.c
+++ b/drivers/staging/media/omap4iss/iss.c
@@ -552,7 +552,11 @@ static int iss_pipeline_is_last(struct
media_entity *me)
 	if (!pipe || pipe->stream_state ==
ISS_PIPELINE_STREAM_STOPPED)
 		return 0;
 	pad = media_pad_remote_pad_first(&pipe->output->pad);
-	return pad->entity == me;
+
+	if (pad)
+		return pad->entity == me;
+
+	return 0;
 }
 
 static int iss_reset(struct iss_device *iss)
diff --git a/drivers/staging/media/omap4iss/iss_csi2.c
b/drivers/staging/media/omap4iss/iss_csi2.c
index 04ce0e7eb557..ab2c2ad64464 100644
--- a/drivers/staging/media/omap4iss/iss_csi2.c
+++ b/drivers/staging/media/omap4iss/iss_csi2.c
@@ -539,6 +539,10 @@ static int csi2_configure(struct iss_csi2_device
*csi2)
 		return -EBUSY;
 
 	pad = media_pad_remote_pad_first(&csi2->pads[CSI2_PAD_SINK]);
+
+	if (!pad)
+		return -EINVAL;
+
 	sensor = media_entity_to_v4l2_subdev(pad->entity);
 	pdata = sensor->host_priv;
 
-- 
2.34.1