From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760613Ab3B0A5t (ORCPT ); Tue, 26 Feb 2013 19:57:49 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:42074 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760305Ab3BZX6D (ORCPT ); Tue, 26 Feb 2013 18:58:03 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ian Abbott Subject: [ 093/150] staging: comedi: disallow COMEDI_DEVCONFIG on non-board minors Date: Tue, 26 Feb 2013 15:55:50 -0800 Message-Id: <20130226235533.745356622@linuxfoundation.org> X-Mailer: git-send-email 1.8.1.rc1.5.g7e0651a In-Reply-To: <20130226235523.930663721@linuxfoundation.org> References: <20130226235523.930663721@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ian Abbott commit 754ab5c0e55dd118273ca2c217c4d95e9fbc8259 upstream. Comedi has two sorts of minor devices: (a) normal board minor devices in the range 0 to COMEDI_NUM_BOARD_MINORS-1 inclusive; and (b) special subdevice minor devices in the range COMEDI_NUM_BOARD_MINORS upwards that are used to open the same underlying comedi device as the normal board minor devices, but with non-default read and write subdevices for asynchronous commands. The special subdevice minor devices get created when a board supporting asynchronous commands is attached to a normal board minor device, and destroyed when the board is detached from the normal board minor device. One way to attach or detach a board is by using the COMEDI_DEVCONFIG ioctl. This should only be used on normal board minors as the special subdevice minors are too ephemeral. In particular, the change introduced in commit 7d3135af399e92cf4c9bbc5f86b6c140aab3b88c ("staging: comedi: prevent auto-unconfig of manually configured devices") breaks horribly for special subdevice minor devices. Since there's no legitimate use for the COMEDI_DEVCONFIG ioctl on a special subdevice minor device node, disallow it and return -ENOTTY. Signed-off-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/comedi_fops.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -1547,6 +1547,11 @@ static long comedi_unlocked_ioctl(struct /* Device config is special, because it must work on * an unconfigured device. */ if (cmd == COMEDI_DEVCONFIG) { + if (minor >= COMEDI_NUM_BOARD_MINORS) { + /* Device config not appropriate on non-board minors. */ + rc = -ENOTTY; + goto done; + } rc = do_devconfig_ioctl(dev, (struct comedi_devconfig __user *)arg); if (rc == 0)