From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1752920AbaGVGzI (ORCPT <rfc822;w@1wt.eu>);
	Tue, 22 Jul 2014 02:55:08 -0400
Received: from cantor2.suse.de ([195.135.220.15]:36240 "EHLO mx2.suse.de"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1752242AbaGVGzF (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Tue, 22 Jul 2014 02:55:05 -0400
Date: Tue, 22 Jul 2014 08:55:03 +0200
Message-ID: <s5htx69hohk.wl%tiwai@suse.de>
From: Takashi Iwai <tiwai@suse.de>
To: Kees Cook <keescook@chromium.org>
Cc: linux-kernel@vger.kernel.org, James Morris <james.l.morris@oracle.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Ming Lei <ming.lei@canonical.com>,
        linux-security-module@vger.kernel.org
Subject: Re: [PATCH v2 2/2] firmware_class: perform new LSM checks
In-Reply-To: <1405969601-4234-3-git-send-email-keescook@chromium.org>
References: <1405969601-4234-1-git-send-email-keescook@chromium.org>
	<1405969601-4234-3-git-send-email-keescook@chromium.org>
User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka)
 FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/24.3
 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO)
MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka")
Content-Type: text/plain; charset=US-ASCII
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

At Mon, 21 Jul 2014 12:06:41 -0700,
Kees Cook wrote:
> 
> This attaches LSM hooks to the existing firmware loading interfaces:
> filesystem-found firmware and demand-loaded blobs.
> 
> Signed-off-by: Kees Cook <keescook@chromium.org>
> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>  drivers/base/firmware_class.c |   16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
> index d276e33880be..7399bab71ced 100644
> --- a/drivers/base/firmware_class.c
> +++ b/drivers/base/firmware_class.c
> @@ -28,6 +28,7 @@
>  #include <linux/suspend.h>
>  #include <linux/syscore_ops.h>
>  #include <linux/reboot.h>
> +#include <linux/security.h>
>  
>  #include <generated/utsrelease.h>
>  
> @@ -308,12 +309,17 @@ static int fw_read_file_contents(struct file *file, struct firmware_buf *fw_buf)
>  	if (rc != size) {
>  		if (rc > 0)
>  			rc = -EIO;
> -		vfree(buf);
> -		return rc;
> +		goto fail;
>  	}
> +	rc = security_kernel_fw_from_file(file, buf, size);
> +	if (rc)
> +		goto fail;
>  	fw_buf->data = buf;
>  	fw_buf->size = size;
>  	return 0;
> +fail:
> +	vfree(buf);
> +	return rc;
>  }
>  
>  static int fw_get_filesystem_firmware(struct device *device,
> @@ -640,6 +646,12 @@ static ssize_t firmware_loading_store(struct device *dev,
>  		break;
>  	case 0:
>  		if (test_bit(FW_STATUS_LOADING, &fw_buf->status)) {
> +			if (security_kernel_fw_from_file(NULL, fw_buf->data,
> +							 fw_buf->size)) {
> +				fw_load_abort(fw_priv);
> +				break;
> +			}
>  			set_bit(FW_STATUS_DONE, &fw_buf->status);
>  			clear_bit(FW_STATUS_LOADING, &fw_buf->status);

security_kernel_fw_from_file() should be called after
fw_map_pages_buf() call (that is found after these lines).
Otherwise fw_buf->buf won't contain a valid buffer pointer.


Takashi