Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758926AbaJ3Msc (ORCPT ); Thu, 30 Oct 2014 08:48:32 -0400 Received: from smtp89.iad3a.emailsrvr.com ([173.203.187.89]:51183 "EHLO smtp89.iad3a.emailsrvr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759848AbaJ3MnF (ORCPT ); Thu, 30 Oct 2014 08:43:05 -0400 X-Sender-Id: abbotti@mev.co.uk From: Ian Abbott To: Cc: Greg Kroah-Hartman , Ian Abbott , H Hartley Sweeten , Subject: [PATCH 5/7] staging: comedi: don't allow write() on async command set up for "read" Date: Thu, 30 Oct 2014 12:42:30 +0000 Message-Id: <1414672952-1587-6-git-send-email-abbotti@mev.co.uk> X-Mailer: git-send-email 2.1.1 In-Reply-To: <1414672952-1587-1-git-send-email-abbotti@mev.co.uk> References: <1414672952-1587-1-git-send-email-abbotti@mev.co.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If a Comedi asynchronous command has been set up for data transfer in the "read" direction on the current "write" subdevice (for those subdevices that support both directions), don't allow the "write" file operation as that would mess with the data in the comedi data buffer that is written by the low-level comedi hardware driver. Signed-off-by: Ian Abbott --- drivers/staging/comedi/comedi_fops.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index 6805ec9..6328965 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -2075,6 +2075,10 @@ static ssize_t comedi_write(struct file *file, const char __user *buf, retval = -EACCES; goto out; } + if (!(async->cmd.flags & CMDF_WRITE)) { + retval = -EINVAL; + goto out; + } add_wait_queue(&async->wait_head, &wait); on_wait_queue = true; @@ -2146,6 +2150,10 @@ static ssize_t comedi_write(struct file *file, const char __user *buf, retval = -EACCES; break; } + if (!(async->cmd.flags & CMDF_WRITE)) { + retval = -EINVAL; + break; + } continue; } -- 2.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/