[PATCH v3 10/12] [media] ddbridge: fix dereference before check

[Daniel Scheller <d.scheller.oss@xxxxxxxxx>]

From: Daniel Scheller <d.scheller@xxxxxxx>

Both ts_release() and ts_open() can use "output" before check (smatch):

  drivers/media/pci/ddbridge/ddbridge-core.c:816 ts_release() warn: variable dereferenced before check 'output' (see line 809)
  drivers/media/pci/ddbridge/ddbridge-core.c:836 ts_open() warn: variable dereferenced before check 'output' (see line 828)

Fix by performing checks on those pointers.

Cc: Ralph Metzler <rjkm@xxxxxxxxxxxxxx>
Signed-off-by: Daniel Scheller <d.scheller@xxxxxxx>
Tested-by: Richard Scobie <r.scobie@xxxxxxxxxxxx>
Tested-by: Jasmin Jessich <jasmin@xxxxxx>
Tested-by: Dietmar Spingler <d_spingler@xxxxxxxxxx>
Tested-by: Manfred Knick <Manfred.Knick@xxxxxxxxxxx>
---
 drivers/media/pci/ddbridge/ddbridge-core.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/media/pci/ddbridge/ddbridge-core.c b/drivers/media/pci/ddbridge/ddbridge-core.c
index 1ec3782a6c88..05db3fb98a86 100644
--- a/drivers/media/pci/ddbridge/ddbridge-core.c
+++ b/drivers/media/pci/ddbridge/ddbridge-core.c
@@ -738,8 +738,13 @@ static unsigned int ts_poll(struct file *file, poll_table *wait)
 static int ts_release(struct inode *inode, struct file *file)
 {
 	struct dvb_device *dvbdev = file->private_data;
-	struct ddb_output *output = dvbdev->priv;
-	struct ddb_input *input = output->port->input[0];
+	struct ddb_output *output = NULL;
+	struct ddb_input *input = NULL;
+
+	if (dvbdev) {
+		output = dvbdev->priv;
+		input = output->port->input[0];
+	}
 
 	if ((file->f_flags & O_ACCMODE) == O_RDONLY) {
 		if (!input)
@@ -757,8 +762,13 @@ static int ts_open(struct inode *inode, struct file *file)
 {
 	int err;
 	struct dvb_device *dvbdev = file->private_data;
-	struct ddb_output *output = dvbdev->priv;
-	struct ddb_input *input = output->port->input[0];
+	struct ddb_output *output = NULL;
+	struct ddb_input *input = NULL;
+
+	if (dvbdev) {
+		output = dvbdev->priv;
+		input = output->port->input[0];
+	}
 
 	if ((file->f_flags & O_ACCMODE) == O_RDONLY) {
 		if (!input)
-- 
2.13.0