USB: cdc-acm: fix sysfs attribute registration bug

This patch (as950) fixes a bug in the cdc-acm driver.  It doesn't keep
track of which interface (control or data) the sysfs attributes get
registered for, and as a result, during disconnect it will sometimes
attempt to remove the attributes from the wrong interface.  The
left-over attributes can cause a crash later on, particularly if the driver
module has been unloaded.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Oliver Neukum <oneukum@suse.de>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/class/cdc-acm.c

@@ -921,6 +921,10 @@ static int acm_probe (struct usb_interface *intf,
 			return -EINVAL;
 		}
 	}
+
+	/* Accept probe requests only for the control interface */
+	if (intf != control_interface)
+		return -ENODEV;
 	
 	if (usb_interface_claimed(data_interface)) { /* valid in this context */
 		dev_dbg(&intf->dev,"The data interface isn't available");
@@ -1109,10 +1113,12 @@ static void acm_disconnect(struct usb_interface *intf)
 		return;
 	}
 	if (acm->country_codes){
-		device_remove_file(&intf->dev, &dev_attr_wCountryCodes);
-		device_remove_file(&intf->dev, &dev_attr_iCountryCodeRelDate);
+		device_remove_file(&acm->control->dev,
+				&dev_attr_wCountryCodes);
+		device_remove_file(&acm->control->dev,
+				&dev_attr_iCountryCodeRelDate);
 	}
-	device_remove_file(&intf->dev, &dev_attr_bmCapabilities);
+	device_remove_file(&acm->control->dev, &dev_attr_bmCapabilities);
 	acm->dev = NULL;
 	usb_set_intfdata(acm->control, NULL);
 	usb_set_intfdata(acm->data, NULL);