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Message-ID: <alpine.DEB.2.22.394.2306271933480.3150@hadrien>
Date: Tue, 27 Jun 2023 19:35:47 +0200 (CEST)
From: Julia Lawall <julia.lawall@...ia.fr>
To: Julia Lawall <Julia.Lawall@...ia.fr>
cc: Sakari Ailus <sakari.ailus@...ux.intel.com>, keescook@...omium.org,
kernel-janitors@...r.kernel.org, Bingbu Cao <bingbu.cao@...el.com>,
Tianshu Qiu <tian.shu.qiu@...el.com>,
Mauro Carvalho Chehab <mchehab@...nel.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
linux-media@...r.kernel.org, linux-staging@...ts.linux.dev,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 23/26] media: staging: imgu: use array_size
On Fri, 23 Jun 2023, Julia Lawall wrote:
> Use array_size to protect against multiplication overflows.
>
> The changes were done using the following Coccinelle semantic patch:
>
> // <smpl>
> @@
> expression E1, E2;
> constant C1, C2;
> identifier alloc = {vmalloc,vzalloc};
> @@
>
> (
> alloc(C1 * C2,...)
> |
> alloc(
> - (E1) * (E2)
> + array_size(E1, E2)
> ,...)
> )
> // </smpl>
>
> Signed-off-by: Julia Lawall <Julia.Lawall@...ia.fr>
>
> ---
> drivers/staging/media/ipu3/ipu3-mmu.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/staging/media/ipu3/ipu3-mmu.c b/drivers/staging/media/ipu3/ipu3-mmu.c
> index cb9bf5fb29a5..9c4adb815c94 100644
> --- a/drivers/staging/media/ipu3/ipu3-mmu.c
> +++ b/drivers/staging/media/ipu3/ipu3-mmu.c
> @@ -464,7 +464,7 @@ struct imgu_mmu_info *imgu_mmu_init(struct device *parent, void __iomem *base)
> * Allocate the array of L2PT CPU pointers, initialized to zero,
> * which means the dummy L2PT allocated above.
> */
> - mmu->l2pts = vzalloc(IPU3_PT_PTES * sizeof(*mmu->l2pts));
> + mmu->l2pts = vzalloc(array_size(IPU3_PT_PTES, sizeof(*mmu->l2pts)));
> if (!mmu->l2pts)
> goto fail_l2pt;
I think that this patch can be dropped. Since it is a multiplcation of
two constants, if there is an overflow, I guess the compiler would detect
it?
julia
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