In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
iommu\/dma: Restore locking around msi_page_list<\/p>\n
Unlike a group’s default domain, which is always freshly allocated
\nand privately owned (iommu_group_alloc_default_domain()), VFIO type1’s
\nlegacy container merges any newly attached group into an existing
\ndomain whenever their iommu_ops and cache-coherency enforcement match.<\/p>\n
iommu_dma_get_msi_page() only asserts the caller’s own group mutex is
\nheld (iommu_group_mutex_assert()). On an IOMMU that publishes
\nIOMMU_RESV_SW_MSI, e.g. ARM SMMU, a VM with two such devices assigned
\nthrough the legacy container can have their guest drivers probe and
\nallocate MSIs in parallel; each host-side VFIO_DEVICE_SET_IRQS lands
\non a different device fd and group mutex, but both devices’ domains
\nare the same merged domain, so both can enter
\niommu_dma_get_msi_page() concurrently and corrupt msi_page_list.<\/p>\n
commit 288683c92b1a (“iommu: Make iommu_dma_prepare_msi() into a
\ngeneric operation”) dropped the prior msi_prepare_lock on the
\nreasoning that “each iommu_domain is unique to a group,” which holds
\nfor default domains but not this VFIO type1 case. Restore the static
\nlock, since it’s only guarding a corner case and will likely never
\nbe contended.<\/p>\n
iommufd avoids the equivalent problem by having its own callers
\n(iommufd_sw_map_msi()) take a ctx-wide sw_msi_lock before ever
\nreaching the shared list. VFIO type1 can’t mirror that since it
\ndispatches to iommu_dma_sw_msi() which is outside VFIO’s jurisdiction.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
iommu\/dma: Restore locking around msi_page_list<\/p>\n
Unlike a group’s default domain, which is always freshly allocated
\nand privately o<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-25653","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/25653","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=25653"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=25653"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=25653"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}