From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
[ Upstream commit 82c3cefb9f1652e7470f442ff96c613e8c8ed8f4 ]
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: c588072bba6b5 ("iommu/vt-d: Convert intel iommu driver to the iommu ops")
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210225061454.2864009-1-baolu.lu@xxxxxxxxxxxxxxx
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/iommu/dma-iommu.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 4078358ed66e..00fbc591a142 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -309,6 +309,11 @@ 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()
@@ -363,8 +368,9 @@ 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");
@@ -521,11 +527,6 @@ 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)
{
--
2.30.1
