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iommu: Don't use lazy flush for untrusted device
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:
parent
765a9d1d02
commit
82c3cefb9f
@ -311,6 +311,11 @@ static void iommu_dma_flush_iotlb_all(struct iova_domain *iovad)
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domain->ops->flush_iotlb_all(domain);
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}
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static bool dev_is_untrusted(struct device *dev)
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{
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return dev_is_pci(dev) && to_pci_dev(dev)->untrusted;
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}
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/**
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* iommu_dma_init_domain - Initialise a DMA mapping domain
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* @domain: IOMMU domain previously prepared by iommu_get_dma_cookie()
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@ -365,8 +370,9 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
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init_iova_domain(iovad, 1UL << order, base_pfn);
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if (!cookie->fq_domain && !iommu_domain_get_attr(domain,
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DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE, &attr) && attr) {
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if (!cookie->fq_domain && (!dev || !dev_is_untrusted(dev)) &&
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!iommu_domain_get_attr(domain, DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE, &attr) &&
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attr) {
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if (init_iova_flush_queue(iovad, iommu_dma_flush_iotlb_all,
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iommu_dma_entry_dtor))
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pr_warn("iova flush queue initialization failed\n");
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@ -508,11 +514,6 @@ static void __iommu_dma_unmap_swiotlb(struct device *dev, dma_addr_t dma_addr,
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iova_align(iovad, size), dir, attrs);
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}
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static bool dev_is_untrusted(struct device *dev)
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{
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return dev_is_pci(dev) && to_pci_dev(dev)->untrusted;
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}
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static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
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size_t size, int prot, u64 dma_mask)
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{
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