2021-05-14 02:06:56

by Gustavo A. R. Silva

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

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 <[email protected]>
---
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)
--
2.27.0

2021-05-24 21:29:02

by Gustavo A. R. Silva

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

On 5/24/21 14:48, Alex Williamson wrote:

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

Thanks, Alex. :)

--
Gustavo

2021-05-24 21:29:20

by Alex Williamson

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

On Thu, 13 May 2021 18:01:55 -0500
"Gustavo A. R. Silva" <[email protected]> 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 <[email protected]>
> ---
> 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