On Thu, Jul 27, 2023 at 01:48:35PM +0800, Lu Baolu wrote:
> @@ -137,6 +136,16 @@ int iommu_queue_iopf(struct iommu_fault *fault, struct device *dev)
> return 0;
> }
>
> + if (fault->prm.flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID)
> + domain = iommu_get_domain_for_dev_pasid(dev, fault->prm.pasid, 0);
> + else
> + domain = iommu_get_domain_for_dev(dev);
How does the lifetime work for this? What prevents UAF on domain?
> diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c
> index ab42cfdd7636..668f4c2bcf65 100644
> --- a/drivers/iommu/iommu-sva.c
> +++ b/drivers/iommu/iommu-sva.c
> @@ -157,7 +157,7 @@ EXPORT_SYMBOL_GPL(iommu_sva_get_pasid);
> /*
> * I/O page fault handler for SVA
> */
> -enum iommu_page_response_code
> +static enum iommu_page_response_code
> iommu_sva_handle_iopf(struct iommu_fault *fault, void *data)
> {
> vm_fault_t ret;
> @@ -241,23 +241,16 @@ static void iopf_handler(struct work_struct *work)
> {
> struct iopf_fault *iopf;
> struct iopf_group *group;
> - struct iommu_domain *domain;
> enum iommu_page_response_code status = IOMMU_PAGE_RESP_SUCCESS;
>
> group = container_of(work, struct iopf_group, work);
> - domain = iommu_get_domain_for_dev_pasid(group->dev,
> - group->last_fault.fault.prm.pasid, 0);
> - if (!domain || !domain->iopf_handler)
> - status = IOMMU_PAGE_RESP_INVALID;
> -
> list_for_each_entry(iopf, &group->faults, list) {
> /*
> * For the moment, errors are sticky: don't handle subsequent
> * faults in the group if there is an error.
> */
> if (status == IOMMU_PAGE_RESP_SUCCESS)
> - status = domain->iopf_handler(&iopf->fault,
> - domain->fault_data);
> + status = iommu_sva_handle_iopf(&iopf->fault, group->data);
> }
>
> iopf_complete_group(group->dev, &group->last_fault, status);
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index 157a28a49473..535a36e3edc9 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -3330,7 +3330,7 @@ struct iommu_domain *iommu_sva_domain_alloc(struct device *dev,
> domain->type = IOMMU_DOMAIN_SVA;
> mmgrab(mm);
> domain->mm = mm;
> - domain->iopf_handler = iommu_sva_handle_iopf;
> + domain->iopf_handler = iommu_sva_handle_iopf_group;
> domain->fault_data = mm;
This also has lifetime problems on the mm.
The domain should flow into the iommu_sva_handle_iopf() instead of the
void *data.
The SVA code can then just use domain->mm directly.
We need to document/figure out some how to ensure that the faults are
all done processing before a fault enabled domain can be freed.
This patch would be better ordered before the prior patch.
Jason
