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iommu: Don't use lazy flush for untrusted device

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The lazy IOTLB flushing setup leaves a time window, in which the device
can still access some system memory, which has already been unmapped by
the device driver. It's not suitable for untrusted devices. A malicious
device might use this to attack the system by obtaining data that it
shouldn't obtain.

Fixes: c588072bba ("iommu/vt-d: Convert intel iommu driver to the iommu ops")
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20210225061454.2864009-1-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Lu Baolu 2021-02-25 14:14:54 +08:00 committed by Joerg Roedel
parent 765a9d1d02
commit 82c3cefb9f
1 changed files with 8 additions and 7 deletions
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15
drivers/iommu/dma-iommu.c
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@ -311,6 +311,11 @@ static void iommu_dma_flush_iotlb_all(struct iova_domain *iovad)
domain->ops->flush_iotlb_all(domain);
}
static bool dev_is_untrusted(struct device *dev)
{
return dev_is_pci(dev) && to_pci_dev(dev)->untrusted;
}
/**
* iommu_dma_init_domain - Initialise a DMA mapping domain
* @domain: IOMMU domain previously prepared by iommu_get_dma_cookie()
@ -365,8 +370,9 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
init_iova_domain(iovad, 1UL << order, base_pfn);
if (!cookie->fq_domain && !iommu_domain_get_attr(domain,
DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE, &attr) && attr) {
if (!cookie->fq_domain && (!dev || !dev_is_untrusted(dev)) &&
!iommu_domain_get_attr(domain, DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE, &attr) &&
attr) {
if (init_iova_flush_queue(iovad, iommu_dma_flush_iotlb_all,
iommu_dma_entry_dtor))
pr_warn("iova flush queue initialization failed\n");
@ -508,11 +514,6 @@ static void __iommu_dma_unmap_swiotlb(struct device *dev, dma_addr_t dma_addr,
iova_align(iovad, size), dir, attrs);
}
static bool dev_is_untrusted(struct device *dev)
{
return dev_is_pci(dev) && to_pci_dev(dev)->untrusted;
}
static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
size_t size, int prot, u64 dma_mask)
{