From: Helge Deller <deller@gmx.de>
To: Hyunwoo Kim <imv4bel@gmail.com>, linux-fbdev@vger.kernel.org
Subject: Re: [PATCH] pxa3xx-gcu: Fix integer overflow in pxa3xx_gcu_write
Date: Mon, 20 Jun 2022 14:50:57 +0200 [thread overview]
Message-ID: <a12be485-3708-a84f-0120-d6938b322e96@gmx.de> (raw)
In-Reply-To: <20220611192851.GA482606@ubuntu>
Hi Hyunwoo,
On 6/11/22 21:28, Hyunwoo Kim wrote:
> 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.
I suggest to simply change the type of "words" a few lines above:
Instead of
int words = count / 4;
use
size_t words = count / 4;
count is already of type size_t and then you don't need to check against < 0.
Can you resend such a patch?
Helge
>
> Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com>
> ---
> 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..5ca6d37e365f 100644
> --- a/drivers/video/fbdev/pxa3xx-gcu.c
> +++ b/drivers/video/fbdev/pxa3xx-gcu.c
> @@ -389,7 +389,7 @@ pxa3xx_gcu_write(struct file *file, const char *buff,
> priv->shared->num_words += words;
>
> /* Last word reserved for batch buffer end command */
> - if (words >= PXA3XX_GCU_BATCH_WORDS)
> + if (words >= PXA3XX_GCU_BATCH_WORDS || words < 0)
> return -E2BIG;
>
> /* Wait for a free buffer */
next prev parent reply other threads:[~2022-06-20 12:51 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-11 19:28 [PATCH] pxa3xx-gcu: Fix integer overflow in pxa3xx_gcu_write Hyunwoo Kim
2022-06-20 12:50 ` Helge Deller [this message]
2022-06-20 14:17 ` Hyunwoo Kim
2022-06-20 18:13 ` Helge Deller
2022-06-20 18:16 ` Hyunwoo Kim
2022-09-20 6:02 Dan Carpenter
2022-09-20 6:13 ` Dan Carpenter
2022-09-20 6:22 ` Hyunwoo Kim
2022-09-20 7:12 ` Dan Carpenter
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