Re: [PATCH] pxa3xx-gcu: Fix integer overflow in pxa3xx_gcu_write

[Helge Deller <deller@gmx.de>]

On 6/20/22 16:17, Hyunwoo Kim wrote:
> From 1c55d1e084071caf02e7739e71e65f52206e872c Mon Sep 17 00:00:00 2001
> From: Hyunwoo Kim <imv4bel@gmail.com>
> Date: Mon, 20 Jun 2022 07:00:10 -0700
> Subject: [PATCH] pxa3xx-gcu: Fix integer overflow in pxa3xx_gcu_write
>
> In pxa3xx_gcu_write, a count parameter of
> type size_t is passed to words of type int.
> Then, copy_from_user may cause a heap overflow because
> it is used as the third argument of copy_from_user.
>
> Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com>

applied.

Thanks!
Helge

> ---
>  drivers/video/fbdev/pxa3xx-gcu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/video/fbdev/pxa3xx-gcu.c b/drivers/video/fbdev/pxa3xx-gcu.c
> index 043cc8f9ef1c..c3cd1e1cc01b 100644
> --- a/drivers/video/fbdev/pxa3xx-gcu.c
> +++ b/drivers/video/fbdev/pxa3xx-gcu.c
> @@ -381,7 +381,7 @@ pxa3xx_gcu_write(struct file *file, const char *buff,
>  	struct pxa3xx_gcu_batch	*buffer;
>  	struct pxa3xx_gcu_priv *priv = to_pxa3xx_gcu_priv(file);
>
> -	int words = count / 4;
> +	size_t words = count / 4;
>
>  	/* Does not need to be atomic. There's a lock in user space,
>  	 * but anyhow, this is just for statistics. */
> --
> 2.25.1
>
> Hello Helge,
>
> Fixed the patch as requested.
>
> Regards,
> Hyunwoo Kim