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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org,
        "Mauro Carvalho Chehab" <mchehab+samsung@kernel.org>,
        "Sylwester Nawrocki" <s.nawrocki@samsung.com>,
        "Dan Carpenter" <dan.carpenter@oracle.com>
Date:   Sun, 09 Dec 2018 21:50:33 +0000
Message-ID: <lsq.1544392233.95153042@decadent.org.uk>
Subject: [PATCH 3.16 022/328] media: exynos4-is: Prevent NULL pointer
 dereference in __isp_video_try_fmt()
In-Reply-To: <lsq.1544392232.713909046@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.62-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Sylwester Nawrocki <s.nawrocki@samsung.com>

commit 7c1b9a5aeed91bef98988ac0fcf38c8c1f4f9a3a upstream.

This patch fixes potential NULL pointer dereference as indicated
by the following static checker warning:

drivers/media/platform/exynos4-is/fimc-isp-video.c:408 isp_video_try_fmt_mplane()
error: NULL dereference inside function '__isp_video_try_fmt(isp, &f->fmt.pix_mp, (0))()'.

Fixes: 34947b8aebe3: ("[media] exynos4-is: Add the FIMC-IS ISP capture DMA driver")

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/media/platform/exynos4-is/fimc-isp-video.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

--- a/drivers/media/platform/exynos4-is/fimc-isp-video.c
+++ b/drivers/media/platform/exynos4-is/fimc-isp-video.c
@@ -390,12 +390,17 @@ static void __isp_video_try_fmt(struct f
 				struct v4l2_pix_format_mplane *pixm,
 				const struct fimc_fmt **fmt)
 {
-	*fmt = fimc_isp_find_format(&pixm->pixelformat, NULL, 2);
+	const struct fimc_fmt *__fmt;
+
+	__fmt = fimc_isp_find_format(&pixm->pixelformat, NULL, 2);
+
+	if (fmt)
+		*fmt = __fmt;
 
 	pixm->colorspace = V4L2_COLORSPACE_SRGB;
 	pixm->field = V4L2_FIELD_NONE;
-	pixm->num_planes = (*fmt)->memplanes;
-	pixm->pixelformat = (*fmt)->fourcc;
+	pixm->num_planes = __fmt->memplanes;
+	pixm->pixelformat = __fmt->fourcc;
 	/*
 	 * TODO: double check with the docmentation these width/height
 	 * constraints are correct.