From: Arnd Bergmann <arnd@arndb.de>
To: Thiago Farina <tfransosi@gmail.com>
Subject: Re: [PATCH] drivers/media/video/v4l2-compat-ioctl32.c: Check the return value of copy_to_user
Date: Tue, 21 Dec 2010 19:25:38 +0100
User-Agent: KMail/1.13.5 (Linux/2.6.37-rc6-next-20101220+; KDE/4.5.1; x86_64; ; )
Cc: linux-kernel@vger.kernel.org,
        Guennadi Liakhovetski <g.liakhovetski@gmx.de>,
        Mauro Carvalho Chehab <mchehab@infradead.org>,
        linux-media@vger.kernel.org
References: <d21ad74592c295d59f5806f30a053745b5765397.1292894256.git.tfransosi@gmail.com>
In-Reply-To: <d21ad74592c295d59f5806f30a053745b5765397.1292894256.git.tfransosi@gmail.com>
MIME-Version: 1.0
Content-Type: Text/Plain;
  charset="utf-8"
Content-Transfer-Encoding: 7bit
Message-Id: <201012211925.38201.arnd@arndb.de>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1309
Lines: 29

On Tuesday 21 December 2010 02:18:06 Thiago Farina wrote:
> diff --git a/drivers/media/video/v4l2-compat-ioctl32.c b/drivers/media/video/v4l2-compat-ioctl32.c
> index e30e8df..55825ec 100644
> --- a/drivers/media/video/v4l2-compat-ioctl32.c
> +++ b/drivers/media/video/v4l2-compat-ioctl32.c
> @@ -206,7 +206,9 @@ static struct video_code __user *get_microcode32(struct video_code32 *kp)
>          * user address is invalid, the native ioctl will do
>          * the error handling for us
>          */
> -       (void) copy_to_user(up->loadwhat, kp->loadwhat, sizeof(up->loadwhat));
> +       if (copy_to_user(up->loadwhat, kp->loadwhat, sizeof(up->loadwhat)))
> +               return NULL;
> +
>         (void) put_user(kp->datasize, &up->datasize);
>         (void) put_user(compat_ptr(kp->data), &up->data);
>         return up;

Did you read the comment above the code you changed?

You can probably change this function to look at the return code of
copy_to_user, but then you need to treat the put_user return code
the same, and change the comment.

	Arnd
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/