Re: [PATCH] pinctrl: samsung: Annotate struct exynos_muxed_weint_data with __counted_by

["Gustavo A. R. Silva" <gustavo@xxxxxxxxxxxxxx>]

On 10/6/23 22:17, Kees Cook wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
> array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
>
> As found with Coccinelle[1], add __counted_by for struct
> exynos_muxed_weint_data. Additionally, since the element count member
> must be set before accessing the annotated flexible array member, move
> its initialization earlier.
>
> Cc: Tomasz Figa <tomasz.figa@xxxxxxxxx>
> Cc: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
> Cc: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
> Cc: Alim Akhtar <alim.akhtar@xxxxxxxxxxx>
> Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
> Cc: "Gustavo A. R. Silva" <gustavoars@xxxxxxxxxx>
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Cc: linux-samsung-soc@xxxxxxxxxxxxxxx
> Cc: linux-gpio@xxxxxxxxxxxxxxx
> Cc: linux-hardening@xxxxxxxxxxxxxxx
> Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>

Reviewed-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>

Thanks!
--
Gustavo

> ---
>   drivers/pinctrl/samsung/pinctrl-exynos.c | 2 +-
>   drivers/pinctrl/samsung/pinctrl-exynos.h | 2 +-
>   2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pinctrl/samsung/pinctrl-exynos.c b/drivers/pinctrl/samsung/pinctrl-exynos.c
> index a8212fc126bf..6b58ec84e34b 100644
> --- a/drivers/pinctrl/samsung/pinctrl-exynos.c
> +++ b/drivers/pinctrl/samsung/pinctrl-exynos.c
> @@ -616,6 +616,7 @@ __init int exynos_eint_wkup_init(struct samsung_pinctrl_drv_data *d)
>   		+ muxed_banks*sizeof(struct samsung_pin_bank *), GFP_KERNEL);
>   	if (!muxed_data)
>   		return -ENOMEM;
> +	muxed_data->nr_banks = muxed_banks;
>   
>   	irq_set_chained_handler_and_data(irq, exynos_irq_demux_eint16_31,
>   					 muxed_data);
> @@ -628,7 +629,6 @@ __init int exynos_eint_wkup_init(struct samsung_pinctrl_drv_data *d)
>   
>   		muxed_data->banks[idx++] = bank;
>   	}
> -	muxed_data->nr_banks = muxed_banks;
>   
>   	return 0;
>   }
> diff --git a/drivers/pinctrl/samsung/pinctrl-exynos.h b/drivers/pinctrl/samsung/pinctrl-exynos.h
> index 7bd6d82c9f36..3ac52c2cf998 100644
> --- a/drivers/pinctrl/samsung/pinctrl-exynos.h
> +++ b/drivers/pinctrl/samsung/pinctrl-exynos.h
> @@ -159,7 +159,7 @@ struct exynos_weint_data {
>    */
>   struct exynos_muxed_weint_data {
>   	unsigned int nr_banks;
> -	struct samsung_pin_bank *banks[];
> +	struct samsung_pin_bank *banks[] __counted_by(nr_banks);
>   };
>   
>   int exynos_eint_gpio_init(struct samsung_pinctrl_drv_data *d);