linux-kernel - Re: [PATCH 5/6] kthread: avoid parsing names as format strings

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Message-ID: <20130612233158.GA19948@dztty>
Date:	Thu, 13 Jun 2013 00:31:58 +0100
From:	Djalal Harouni <tixxdz@...ndz.org>
To:	Kees Cook <keescook@...omium.org>
Cc:	linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jens Axboe <axboe@...nel.dk>,
	"David S. Miller" <davem@...emloft.net>,
	Herbert Xu <herbert@...dor.hengli.com.au>,
	David Woodhouse <dwmw2@...radead.org>,
	Karsten Keil <isdn@...ux-pingi.de>
Subject: Re: [PATCH 5/6] kthread: avoid parsing names as format strings

Hi Kees,

On Fri, Jun 07, 2013 at 04:50:54PM -0700, Kees Cook wrote:
> Calling kthread_run with a single name parameter causes it to be handled
> as a format string. Many callers are passing potentially dynamic string
> content, so use "%s" in those cases to avoid any potential accidents.
> 
> Signed-off-by: Kees Cook <keescook@...omium.org>
> ---
>  drivers/block/aoe/aoecmd.c           |    2 +-
>  drivers/block/mtip32xx/mtip32xx.c    |    3 ++-
[...]
> diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
> index 847107e..81ce4c0 100644
> --- a/drivers/block/mtip32xx/mtip32xx.c
> +++ b/drivers/block/mtip32xx/mtip32xx.c
> @@ -4085,7 +4085,8 @@ skip_create_disk:
>  start_service_thread:
>  	sprintf(thd_name, "mtip_svc_thd_%02d", index);
We can also save some bytes here, remove the sprintf() and thd_name[]

>  	dd->mtip_svc_handler = kthread_create_on_node(mtip_service_thread,
> -						dd, dd->numa_node, thd_name);
> +						dd, dd->numa_node, "%s",
> +						thd_name);
>  
>  	if (IS_ERR(dd->mtip_svc_handler)) {
>  		dev_err(&dd->pdev->dev, "service thread failed to start\n");

Thanks!

-- 
Djalal Harouni
http://opendz.org
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