media: ddbridge: fix dereference before check

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@metzlerbros.de>
Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Tested-by: Richard Scobie <r.scobie@clear.net.nz>
Tested-by: Jasmin Jessich <jasmin@anw.at>
Tested-by: Dietmar Spingler <d_spingler@freenet.de>
Tested-by: Manfred Knick <Manfred.Knick@t-online.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

diff --git a/drivers/media/pci/ddbridge/ddbridge-core.c b/drivers/media/pci/ddbridge/ddbridge-core.c
index 66b520d..e051a69 100644 (file)
--- 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)