From b9eb3ab6f30bf32f7326909f17949ccb11bab514 Mon Sep 17 00:00:00 2001
From: Sakari Ailus <sakari.ailus@linux.intel.com>
Date: Thu, 25 Aug 2022 20:36:37 +0200
Subject: [PATCH] media: ipu3-imgu: Fix NULL pointer dereference in active selection access
Git-commit: b9eb3ab6f30bf32f7326909f17949ccb11bab514
Patch-mainline: v6.1-rc2
References: git-fixes

What the IMGU driver did was that it first acquired the pointers to active
and try V4L2 subdev state, and only then figured out which one to use.

The problem with that approach and a later patch (see Fixes: tag) is that
as sd_state argument to v4l2_subdev_get_try_crop() et al is NULL, there is
now an attempt to dereference that.

Fix this.

Also rewrap lines a little.

Fixes: 0d346d2a6f54 ("media: v4l2-subdev: add subdev-wide state struct")
Cc: stable@vger.kernel.org # for v5.14 and later
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Bingbu Cao <bingbu.cao@intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/staging/media/ipu3/ipu3-v4l2.c | 31 ++++++++++++--------------
 1 file changed, 14 insertions(+), 17 deletions(-)

diff --git a/drivers/staging/media/ipu3/ipu3-v4l2.c b/drivers/staging/media/ipu3/ipu3-v4l2.c
index d1c539cefba8..2234bb8d48b3 100644
--- a/drivers/staging/media/ipu3/ipu3-v4l2.c
+++ b/drivers/staging/media/ipu3/ipu3-v4l2.c
@@ -192,33 +192,30 @@ static int imgu_subdev_get_selection(struct v4l2_subdev *sd,
 				     struct v4l2_subdev_state *sd_state,
 				     struct v4l2_subdev_selection *sel)
 {
-	struct v4l2_rect *try_sel, *r;
-	struct imgu_v4l2_subdev *imgu_sd = container_of(sd,
-							struct imgu_v4l2_subdev,
-							subdev);
+	struct imgu_v4l2_subdev *imgu_sd =
+		container_of(sd, struct imgu_v4l2_subdev, subdev);
 
 	if (sel->pad != IMGU_NODE_IN)
 		return -EINVAL;
 
 	switch (sel->target) {
 	case V4L2_SEL_TGT_CROP:
-		try_sel = v4l2_subdev_get_try_crop(sd, sd_state, sel->pad);
-		r = &imgu_sd->rect.eff;
-		break;
+		if (sel->which == V4L2_SUBDEV_FORMAT_TRY)
+			sel->r = *v4l2_subdev_get_try_crop(sd, sd_state,
+							   sel->pad);
+		else
+			sel->r = imgu_sd->rect.eff;
+		return 0;
 	case V4L2_SEL_TGT_COMPOSE:
-		try_sel = v4l2_subdev_get_try_compose(sd, sd_state, sel->pad);
-		r = &imgu_sd->rect.bds;
-		break;
+		if (sel->which == V4L2_SUBDEV_FORMAT_TRY)
+			sel->r = *v4l2_subdev_get_try_compose(sd, sd_state,
+							      sel->pad);
+		else
+			sel->r = imgu_sd->rect.bds;
+		return 0;
 	default:
 		return -EINVAL;
 	}
-
-	if (sel->which == V4L2_SUBDEV_FORMAT_TRY)
-		sel->r = *try_sel;
-	else
-		sel->r = *r;
-
-	return 0;
 }
 
 static int imgu_subdev_set_selection(struct v4l2_subdev *sd,
-- 
2.35.3