[PATCH AUTOSEL 4.9 106/251] media: tw5864: Fix possible NULL pointer dereference in tw5864_handle_frame

Sasha Levin
2020-01-16T18:09:44Z

From: YueHaibing <yuehaibing@huawei.com>

[ Upstream commit 2e7682ebfc750177a4944eeb56e97a3f05734528 ]

'vb' null check should be done before dereferencing it in
tw5864_handle_frame, otherwise a NULL pointer dereference
may occur.

Fixes: 34d1324edd31 ("[media] pci: Add tw5864 driver")

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/media/pci/tw5864/tw5864-video.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/media/pci/tw5864/tw5864-video.c b/drivers/media/pci/tw5864/tw5864-video.c
index 1ddf80f85c24..27ff6e0d9845 100644
--- a/drivers/media/pci/tw5864/tw5864-video.c
+++ b/drivers/media/pci/tw5864/tw5864-video.c
@@ -1386,13 +1386,13 @@ static void tw5864_handle_frame(struct tw5864_h264_frame *frame)
input->vb = NULL;
spin_unlock_irqrestore(&input->slock, flags);

- v4l2_buf = to_vb2_v4l2_buffer(&vb->vb.vb2_buf);
-
if (!vb) { /* Gone because of disabling */
dev_dbg(&dev->pci->dev, "vb is empty, dropping frame\n");
return;
}

+ v4l2_buf = to_vb2_v4l2_buffer(&vb->vb.vb2_buf);
+
/*
* Check for space.
* Mind the overhead of startcode emulation prevention.
--
2.20.1