linux-kernel - Re: [PATCH 1/3] kobject : kobject_set_name

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Date:	Thu, 14 May 2009 20:04:31 +0800
From:	Dave Young <hidave.darkstar@...il.com>
To:	Greg KH <gregkh@...e.de>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/3] kobject : kobject_set_name_vargs leak fix

On Mon, May 11, 2009 at 2:16 PM, Dave Young <hidave.darkstar@...il.com> wrote:
> kobject_set_name_vargs will leak the old_name when return -ENOMEM,
> move the kfree(old_name) before the return path.

Hi, greg

I rethought about this problem, does such issue exist really? I means
that kobject->name != NULL scenario.

there's following comments of this function:

 * This sets the name of the kobject.  If you have already added the
 * kobject to the system, you must call kobject_rename() in order to
 * change the name of the kobject

So what if something like :

if (kobject->name) {
 WARN(1, KERN_WARNING, "there's name for kobject already!");
 return -EINVAL;
}

if (!fmt)
 return 0;

>
> Signed-off-by: Dave Young <hidave.darkstar@...il.com>
> ---
> lib/kobject.c |    2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff -uprN linux.old/lib/kobject.c linux.new/lib/kobject.c
> --- linux.old/lib/kobject.c     2009-05-11 13:59:01.000000000 +0800
> +++ linux.new/lib/kobject.c     2009-05-11 13:59:34.000000000 +0800
> @@ -221,6 +221,7 @@ int kobject_set_name_vargs(struct kobjec
>        if (kobj->name && !fmt)
>                return 0;
>
> +       kfree(old_name);
>        kobj->name = kvasprintf(GFP_KERNEL, fmt, vargs);
>        if (!kobj->name)
>                return -ENOMEM;
> @@ -229,7 +230,6 @@ int kobject_set_name_vargs(struct kobjec
>        while ((s = strchr(kobj->name, '/')))
>                s[0] = '!';
>
> -       kfree(old_name);
>        return 0;
>  }
>



-- 
Regards
dave
--
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