Re: [PATCH 02/21] dmaengine: at_hdmac: Annotate struct at_desc with __counted_by

Gustavo A. R. Silva
2023-08-18T03:33:42Z

On 8/17/23 17:58, 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 at_desc.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: Vinod Koul <vkoul@kernel.org>
> Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
> Cc: Tudor Ambarus <tudor.ambarus@linaro.org>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: dmaengine@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

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

Thanks
--
Gustavo

> ---
> drivers/dma/at_hdmac.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
> index b2876f67471f..b66c7f416881 100644
> --- a/drivers/dma/at_hdmac.c
> +++ b/drivers/dma/at_hdmac.c
> @@ -239,7 +239,7 @@ struct at_desc {
> bool memset_buffer;
> dma_addr_t memset_paddr;
> int *memset_vaddr;
> - struct atdma_sg sg[];
> + struct atdma_sg sg[] __counted_by(sglen);
> };
>
> /*-- Channels --------------------------------------------------------*/