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Message-ID: <7ab98b69-8aac-416e-95b5-6105c63f4fd1@embeddedor.com>
Date:   Sat, 23 Sep 2023 10:35:59 -0600
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Subject: Re: [PATCH] bus: vexpress-config: Annotate struct
 vexpress_syscfg_func with __counted_by
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To:     Kees Cook <keescook@chromium.org>,
        Liviu Dudau <liviu.dudau@arm.com>
Cc:     Sudeep Holla <sudeep.holla@arm.com>,
        Lorenzo Pieralisi <lpieralisi@kernel.org>,
        Rob Herring <robh@kernel.org>, Yangtao Li <frank.li@vivo.com>,
        linux-arm-kernel@lists.infradead.org,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>, linux-kernel@vger.kernel.org,
        llvm@lists.linux.dev, linux-hardening@vger.kernel.org
References: <20230922175234.work.134-kees@kernel.org>
From:   "Gustavo A. R. Silva" <gustavo@embeddedor.com>
In-Reply-To: <20230922175234.work.134-kees@kernel.org>
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On 9/22/23 11:52, 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 checking 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 vexpress_syscfg_func.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Liviu Dudau <liviu.dudau@arm.com>
> Cc: Sudeep Holla <sudeep.holla@arm.com>
> Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Yangtao Li <frank.li@vivo.com>
> Cc: linux-arm-kernel@lists.infradead.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

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

Thanks
-- 
Gustavo

> ---
>   drivers/bus/vexpress-config.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/bus/vexpress-config.c b/drivers/bus/vexpress-config.c
> index c4e1becbb2d2..d2c7ada90186 100644
> --- a/drivers/bus/vexpress-config.c
> +++ b/drivers/bus/vexpress-config.c
> @@ -54,7 +54,7 @@ struct vexpress_syscfg_func {
>   	struct vexpress_syscfg *syscfg;
>   	struct regmap *regmap;
>   	int num_templates;
> -	u32 template[]; /* Keep it last! */
> +	u32 template[] __counted_by(num_templates); /* Keep it last! */
>   };
>   
>   struct vexpress_config_bridge_ops {