USB: cdc-acm: check for valid interfaces

We need to check that we have both a valid data and control inteface for both
types of headers (union and not union.)

References: https://bugzilla.kernel.org/show_bug.cgi?id=83551
Reported-by: Simon Schubert <2+kernel@0x2c.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 5 insertions, 4 deletions

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 6c6a5c4cc68c..546a17e8ad5b 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1195,10 +1195,11 @@ next_desc:
         } else {
                 control_interface = usb_ifnum_to_if(usb_dev, union_header->bMasterInterface0);
                 data_interface = usb_ifnum_to_if(usb_dev, (data_interface_num = union_header->bSlaveInterface0));
-                if (!control_interface || !data_interface) {
-                        dev_dbg(&intf->dev, "no interfaces\n");
-                        return -ENODEV;
-                }
+        }
+
+        if (!control_interface || !data_interface) {
+                dev_dbg(&intf->dev, "no interfaces\n");
+                return -ENODEV;
         }
 
         if (data_interface_num != call_interface_num)