Re: [PATCH 07/21] dmaengine: qcom: bam_dma: Annotate struct bam_async_desc with __counted_by

[Gustavo A. R. Silva]

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 bam_async_desc.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: Vinod Koul <vkoul@xxxxxxxxxx>
> Cc: Andy Gross <agross@xxxxxxxxxx>
> Cc: Bjorn Andersson <andersson@xxxxxxxxxx>
> Cc: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx>
> Cc: linux-arm-msm@xxxxxxxxxxxxxxx
> Cc: dmaengine@xxxxxxxxxxxxxxx
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>

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

Thanks
--
Gustavo

> ---
>   drivers/dma/qcom/bam_dma.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
> index 4c3eb972039d..65b89bb7a56b 100644
> --- a/drivers/dma/qcom/bam_dma.c
> +++ b/drivers/dma/qcom/bam_dma.c
> @@ -74,7 +74,7 @@ struct bam_async_desc {
>   	struct list_head desc_node;
>   	enum dma_transfer_direction dir;
>   	size_t length;
> -	struct bam_desc_hw desc[];
> +	struct bam_desc_hw desc[] __counted_by(num_desc);
>   };
>   
>   enum bam_reg {