Re: [PATCH] i3c/master/mipi-i3c-hci: Annotate struct hci_rings_data with __counted_by

From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: Kees Cook <keescook@chromium.org>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Nicolas Pitre <npitre@baylibre.com>,
	Len Baker <len.baker@gmx.com>,
	Boris Brezillon <boris.brezillon@collabora.com>,
	linux-i3c@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
Subject: Re: [PATCH] i3c/master/mipi-i3c-hci: Annotate struct hci_rings_data with __counted_by
Date: Sat, 23 Sep 2023 10:28:52 -0600	[thread overview]
Message-ID: <9ae58a8a-04c1-90ac-cf50-7366bff42084@embeddedor.com> (raw)
In-Reply-To: <20230922175019.work.129-kees@kernel.org>


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 hci_rings_data.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
> Cc: Nicolas Pitre <npitre@baylibre.com>
> Cc: Len Baker <len.baker@gmx.com>
> Cc: Boris Brezillon <boris.brezillon@collabora.com>
> Cc: linux-i3c@lists.infradead.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

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

Thanks
-- 
Gustavo

> ---
>   drivers/i3c/master/mipi-i3c-hci/dma.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/i3c/master/mipi-i3c-hci/dma.c b/drivers/i3c/master/mipi-i3c-hci/dma.c
> index 2990ac9eaade..a1ecdfc35641 100644
> --- a/drivers/i3c/master/mipi-i3c-hci/dma.c
> +++ b/drivers/i3c/master/mipi-i3c-hci/dma.c
> @@ -139,7 +139,7 @@ struct hci_rh_data {
>   
>   struct hci_rings_data {
>   	unsigned int total;
> -	struct hci_rh_data headers[];
> +	struct hci_rh_data headers[] __counted_by(total);
>   };
>   
>   struct hci_dma_dev_ibi_data {