media: dvbdev: drop refcount on error path in dvb_device_open()

[ Upstream commit a2dd235df435a05d389240be748909ada91201d2 ]

If call to file->f_op->open() fails, then call dvb_device_put(dvbdev).

Fixes: 0fc044b2b5e2 ("media: dvbdev: adopts refcnt to avoid UAF")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/media/dvb-core/dvbdev.c b/drivers/media/dvb-core/dvbdev.c
index 305bb21..49f0eb7 100644 (file)
--- a/drivers/media/dvb-core/dvbdev.c
+++ b/drivers/media/dvb-core/dvbdev.c
@@ -104,6 +104,8 @@ static int dvb_device_open(struct inode *inode, struct file *file)
                        err = file->f_op->open(inode, file);
                up_read(&minor_rwsem);
                mutex_unlock(&dvbdev_mutex);
+               if (err)
+                       dvb_device_put(dvbdev);
                return err;
        }
 fail: