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

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Message-ID: <20090512162908.GF16247@kroah.com>
Date:	Tue, 12 May 2009 09:29:08 -0700
From:	Greg KH <greg@...ah.com>
To:	Dave Young <hidave.darkstar@...il.com>
Cc:	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 02:16:36PM +0800, Dave Young wrote:
> kobject_set_name_vargs will leak the old_name when return -ENOMEM,
> move the kfree(old_name) before the return path.
> 
> 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;
>  }

No, it would be safer to put the kobj->name pointer back to old_name if
the kvasprintf() call failed.  That way the caller can properly clean up
if needed.

Care to respin this?

thanks,

greg k-h
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