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Message-ID: <781aa943-29de-2992-e68f-1bc062a3f4fe@embeddedor.com>
Date:   Sat, 23 Sep 2023 10:29:03 -0600
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Subject: Re: [PATCH] input: Annotate struct evdev_client with __counted_by
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To:     Kees Cook <keescook@chromium.org>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc:     linux-input@vger.kernel.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: <20230922175027.work.563-kees@kernel.org>
From:   "Gustavo A. R. Silva" <gustavo@embeddedor.com>
In-Reply-To: <20230922175027.work.563-kees@kernel.org>
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On 9/22/23 11:50, 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 evdev_client.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> Cc: linux-input@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

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

Thanks
-- 
Gustavo

> ---
>   drivers/input/evdev.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
> index 95f90699d2b1..51e0c4954600 100644
> --- a/drivers/input/evdev.c
> +++ b/drivers/input/evdev.c
> @@ -50,7 +50,7 @@ struct evdev_client {
>   	bool revoked;
>   	unsigned long *evmasks[EV_CNT];
>   	unsigned int bufsize;
> -	struct input_event buffer[];
> +	struct input_event buffer[] __counted_by(bufsize);
>   };
>   
>   static size_t evdev_get_mask_cnt(unsigned int type)