Re: [PATCH v2] virt: vbox: fix memory leak in hgcm_call_preprocess_linaddr

From: Hans de Goede <hdegoede@redhat.com>
To: Navid Emamdoost <navid.emamdoost@gmail.com>
Cc: emamd001@umn.edu, smccaman@umn.edu, kjlu@umn.edu,
	Arnd Bergmann <arnd@arndb.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] virt: vbox: fix memory leak in hgcm_call_preprocess_linaddr
Date: Tue, 1 Oct 2019 08:15:23 +0200	[thread overview]
Message-ID: <48a2ad9b-bcdb-6146-0911-37961e07b1d9@redhat.com> (raw)
In-Reply-To: <20190930204223.3660-1-navid.emamdoost@gmail.com>

Hi,

On 30-09-2019 22:42, Navid Emamdoost wrote:
> In hgcm_call_preprocess_linaddr memory is allocated for bounce_buf but
> is not released if copy_form_user fails. In order to prevent memory leak
> in case of failure, the assignment to bounce_buf_ret is moved before the
> error check. This way the allocated bounce_buf will be released by the
> caller.
> 
> Fixes: 579db9d45cb4 ("virt: Add vboxguest VMMDEV communication code")
> Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>

Thank you.

Patch looks good to me:

Reviewed-by: Hans de Goede <hdegoede@redhat.com>

Regards,

Hans

> ---
>   drivers/virt/vboxguest/vboxguest_utils.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/virt/vboxguest/vboxguest_utils.c b/drivers/virt/vboxguest/vboxguest_utils.c
> index 75fd140b02ff..43c391626a00 100644
> --- a/drivers/virt/vboxguest/vboxguest_utils.c
> +++ b/drivers/virt/vboxguest/vboxguest_utils.c
> @@ -220,6 +220,8 @@ static int hgcm_call_preprocess_linaddr(
>   	if (!bounce_buf)
>   		return -ENOMEM;
>   
> +	*bounce_buf_ret = bounce_buf;
> +
>   	if (copy_in) {
>   		ret = copy_from_user(bounce_buf, (void __user *)buf, len);
>   		if (ret)
> @@ -228,7 +230,6 @@ static int hgcm_call_preprocess_linaddr(
>   		memset(bounce_buf, 0, len);
>   	}
>   
> -	*bounce_buf_ret = bounce_buf;
>   	hgcm_call_add_pagelist_size(bounce_buf, len, extra);
>   	return 0;
>   }
> 