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

Gustavo A. R. Silva
2023-08-18T01:25:30Z

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@kernel.org>
> Cc: Andy Gross <agross@kernel.org>
> Cc: Bjorn Andersson <andersson@kernel.org>
> Cc: Konrad Dybcio <konrad.dybcio@linaro.org>
> Cc: linux-arm-msm@vger.kernel.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/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 {