From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965694AbbCPPXJ (ORCPT ); Mon, 16 Mar 2015 11:23:09 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:55288 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932762AbbCPOSv (ORCPT ); Mon, 16 Mar 2015 10:18:51 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ian Abbott , H Hartley Sweeten Subject: [PATCH 3.19 133/177] staging: comedi: comedi_compat32.c: fix COMEDI_CMD copy back Date: Mon, 16 Mar 2015 15:09:00 +0100 Message-Id: <20150316140819.145656239@linuxfoundation.org> X-Mailer: git-send-email 2.3.3 In-Reply-To: <20150316140813.085032723@linuxfoundation.org> References: <20150316140813.085032723@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ian Abbott commit 42b8ce6f55facfa101462e694d33fc6bca471138 upstream. `do_cmd_ioctl()` in "comedi_fops.c" handles the `COMEDI_CMD` ioctl. This returns `-EAGAIN` if it has copied a modified `struct comedi_cmd` back to user-space. (This occurs when the low-level Comedi driver's `do_cmdtest()` handler returns non-zero to indicate a problem with the contents of the `struct comedi_cmd`, or when the `struct comedi_cmd` has the `CMDF_BOGUS` flag set.) `compat_cmd()` in "comedi_compat32.c" handles the 32-bit compatible version of the `COMEDI_CMD` ioctl. Currently, it never copies a 32-bit compatible version of `struct comedi_cmd` back to user-space, which is at odds with the way the regular `COMEDI_CMD` ioctl is handled. To fix it, change `compat_cmd()` to copy a 32-bit compatible version of the `struct comedi_cmd` back to user-space when the main ioctl handler returns `-EAGAIN`. Signed-off-by: Ian Abbott Reviewed-by: H Hartley Sweeten Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/comedi_compat32.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) --- a/drivers/staging/comedi/comedi_compat32.c +++ b/drivers/staging/comedi/comedi_compat32.c @@ -262,7 +262,7 @@ static int compat_cmd(struct file *file, { struct comedi_cmd __user *cmd; struct comedi32_cmd_struct __user *cmd32; - int rc; + int rc, err; cmd32 = compat_ptr(arg); cmd = compat_alloc_user_space(sizeof(*cmd)); @@ -271,7 +271,15 @@ static int compat_cmd(struct file *file, if (rc) return rc; - return translated_ioctl(file, COMEDI_CMD, (unsigned long)cmd); + rc = translated_ioctl(file, COMEDI_CMD, (unsigned long)cmd); + if (rc == -EAGAIN) { + /* Special case: copy cmd back to user. */ + err = put_compat_cmd(cmd32, cmd); + if (err) + rc = err; + } + + return rc; } /* Handle 32-bit COMEDI_CMDTEST ioctl. */