1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c
index 7482d0d5e278..67eb8390cf07 100644
--- a/drivers/net/usb/hso.c
+++ b/drivers/net/usb/hso.c
@@ -1723,6 +1723,10 @@ static int hso_serial_tiocmset(struct tty_struct *tty, struct file *file,
                 D1("no tty structures");
                 return -EINVAL;
         }
+
+        if ((serial->parent->port_spec & HSO_PORT_MASK) != HSO_PORT_MODEM)
+                return -EINVAL;
+
         if_num = serial->parent->interface->altsetting->desc.bInterfaceNumber;
 
         spin_lock_irqsave(&serial->serial_lock, flags);