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From:   Jia-Ju Bai <baijiaju1990@gmail.com>
To:     stanimir.varbanov@linaro.org, agross@kernel.org, mchehab@kernel.org
Cc:     linux-media@vger.kernel.org, linux-arm-msm@vger.kernel.org,
        linux-kernel@vger.kernel.org, Jia-Ju Bai <baijiaju1990@gmail.com>
Subject: [PATCH] media: qcom: venus: Fix a possible null-pointer dereference in vdec_g_fmt()
Date:   Sat, 27 Jul 2019 17:15:47 +0800
Message-Id: <20190727091547.11674-1-baijiaju1990@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

In vdec_g_fmt(), fmt is firstly assigned NULL, and it could be never
assigned before being used on line 223:
    pixmp->pixelformat = fmt->pixfmt;

Thus, a possible null-pointer dereference may occur.

To fix this bug, fmt is checked before being used here.

This bug is found by a static analysis tool STCheck written by us.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
 drivers/media/platform/qcom/venus/vdec.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/qcom/venus/vdec.c b/drivers/media/platform/qcom/venus/vdec.c
index e1f998656c07..12c31551f191 100644
--- a/drivers/media/platform/qcom/venus/vdec.c
+++ b/drivers/media/platform/qcom/venus/vdec.c
@@ -211,7 +211,8 @@ static int vdec_g_fmt(struct file *file, void *fh, struct v4l2_format *f)
 		inst->height = format.fmt.pix_mp.height;
 	}
 
-	pixmp->pixelformat = fmt->pixfmt;
+	if (fmt)
+		pixmp->pixelformat = fmt->pixfmt;
 
 	if (f->type == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE) {
 		pixmp->width = inst->width;
-- 
2.17.0