USB: cdc-acm: check for valid interfaces

commit 403dff4e2c94f275e24fd85f40b2732ffec268a1 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 6647081..d38d88e 100644 (file)
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1011,10 +1011,11 @@ 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)