Re: [PATCH] dmaengine: ep93xx_dma: Annotate struct ep93xx_dma_engine with __counted_by

[Gustavo A. R. Silva]

On 9/29/23 01:43, 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 ep93xx_dma_engine.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: Vinod Koul <vkoul@xxxxxxxxxx>
> Cc: Nathan Chancellor <nathan@xxxxxxxxxx>
> Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> Cc: Tom Rix <trix@xxxxxxxxxx>
> Cc: dmaengine@xxxxxxxxxxxxxxx
> Cc: llvm@xxxxxxxxxxxxxxx
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>

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

Thanks
--
Gustavo

> ---
>   drivers/dma/ep93xx_dma.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/dma/ep93xx_dma.c b/drivers/dma/ep93xx_dma.c
> index 5c4a448a1254..d6c60635e90d 100644
> --- a/drivers/dma/ep93xx_dma.c
> +++ b/drivers/dma/ep93xx_dma.c
> @@ -213,7 +213,7 @@ struct ep93xx_dma_engine {
>   #define INTERRUPT_NEXT_BUFFER	2
>   
>   	size_t			num_channels;
> -	struct ep93xx_dma_chan	channels[];
> +	struct ep93xx_dma_chan	channels[] __counted_by(num_channels);
>   };
>   
>   static inline struct device *chan2dev(struct ep93xx_dma_chan *edmac)