Re: [PATCH v8 7/7] iommu/vt-d: Check UAPI data processed by IOMMU core

[Lu Baolu]

Hi Jacob,

On 9/1/20 2:25 AM, Jacob Pan wrote:
> IOMMU generic layer already does sanity checks on UAPI data for version
> match and argsz range based on generic information.
>
> This patch adjusts the following data checking responsibilities:
> - removes the redundant version check from VT-d driver
> - removes the check for vendor specific data size
> - adds check for the use of reserved/undefined flags
>
> Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> ---
>   drivers/iommu/intel/iommu.c |  3 +--
>   drivers/iommu/intel/svm.c   | 11 +++++++++--
>   include/uapi/linux/iommu.h  |  1 +
>   3 files changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 43f16f0cebde..a3a0b5c8921d 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -5399,8 +5399,7 @@ intel_iommu_sva_invalidate(struct iommu_domain *domain, struct device *dev,
>   	int ret = 0;
>   	u64 size = 0;
>   
> -	if (!inv_info || !dmar_domain ||
> -	    inv_info->version != IOMMU_CACHE_INVALIDATE_INFO_VERSION_1)
> +	if (!inv_info || !dmar_domain)
>   		return -EINVAL;
>   
>   	if (!dev || !dev_is_pci(dev))
> diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
> index 99353d6468fa..0cb9a15f1112 100644
> --- a/drivers/iommu/intel/svm.c
> +++ b/drivers/iommu/intel/svm.c
> @@ -284,8 +284,15 @@ int intel_svm_bind_gpasid(struct iommu_domain *domain, struct device *dev,
>   	if (WARN_ON(!iommu) || !data)
>   		return -EINVAL;
>   
> -	if (data->version != IOMMU_GPASID_BIND_VERSION_1 ||
> -	    data->format != IOMMU_PASID_FORMAT_INTEL_VTD)
> +	if (data->format != IOMMU_PASID_FORMAT_INTEL_VTD)
> +		return -EINVAL;
> +
> +	/* IOMMU core ensures argsz is more than the start of the union */
> +	if (data->argsz < offsetofend(struct iommu_gpasid_bind_data, vendor.vtd))
> +		return -EINVAL;
> +
> +	/* Make sure no undefined flags are used in vendor data */
> +	if (data->vendor.vtd.flags & ~(IOMMU_SVA_VTD_GPASID_LAST - 1))
>   		return -EINVAL;
>   
>   	if (!dev_is_pci(dev))
> diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h
> index c64bca5af419..1ebc23df4fbc 100644
> --- a/include/uapi/linux/iommu.h
> +++ b/include/uapi/linux/iommu.h
> @@ -288,6 +288,7 @@ struct iommu_gpasid_bind_data_vtd {
>   #define IOMMU_SVA_VTD_GPASID_PWT	(1 << 3) /* page-level write through */
>   #define IOMMU_SVA_VTD_GPASID_EMTE	(1 << 4) /* extended mem type enable */
>   #define IOMMU_SVA_VTD_GPASID_CD		(1 << 5) /* PASID-level cache disable */
> +#define IOMMU_SVA_VTD_GPASID_LAST	(1 << 6)
>   	__u64 flags;
>   	__u32 pat;
>   	__u32 emt;

Reviewed-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>

Best regards,
baolu