Re: [PATCH][next] vfio/iommu_type1: Use struct_size() for kzalloc()

[Alex Williamson]

On Thu, 13 May 2021 18:01:55 -0500
"Gustavo A. R. Silva" <gustavoars@xxxxxxxxxx> wrote:

> Make use of the struct_size() helper instead of an open-coded version,
> in order to avoid any potential type mistakes or integer overflows
> that, in the worst scenario, could lead to heap overflows.
> 
> This code was detected with the help of Coccinelle and, audited and
> fixed manually.
> 
> Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
> ---
>  drivers/vfio/vfio_iommu_type1.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index a0747c35a778..a3e925a41b0d 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -2795,7 +2795,7 @@ static int vfio_iommu_iova_build_caps(struct vfio_iommu *iommu,
>  		return 0;
>  	}
>  
> -	size = sizeof(*cap_iovas) + (iovas * sizeof(*cap_iovas->iova_ranges));
> +	size = struct_size(cap_iovas, iova_ranges, iovas);
>  
>  	cap_iovas = kzalloc(size, GFP_KERNEL);
>  	if (!cap_iovas)


Looks good, applied to vfio for-linus branch for v5.13.  Thanks,

Alex