CVE-2024-56669

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> iommu/vt-d: Remove cache tags before disabling ATS<br /> <br /> The current implementation removes cache tags after disabling ATS,<br /> leading to potential memory leaks and kernel crashes. Specifically,<br /> CACHE_TAG_DEVTLB type cache tags may still remain in the list even<br /> after the domain is freed, causing a use-after-free condition.<br /> <br /> This issue really shows up when multiple VFs from different PFs<br /> passed through to a single user-space process via vfio-pci. In such<br /> cases, the kernel may crash with kernel messages like:<br /> <br /> BUG: kernel NULL pointer dereference, address: 0000000000000014<br /> PGD 19036a067 P4D 1940a3067 PUD 136c9b067 PMD 0<br /> Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI<br /> CPU: 74 UID: 0 PID: 3183 Comm: testCli Not tainted 6.11.9 #2<br /> RIP: 0010:cache_tag_flush_range+0x9b/0x250<br /> Call Trace:<br /> <br /> ? __die+0x1f/0x60<br /> ? page_fault_oops+0x163/0x590<br /> ? exc_page_fault+0x72/0x190<br /> ? asm_exc_page_fault+0x22/0x30<br /> ? cache_tag_flush_range+0x9b/0x250<br /> ? cache_tag_flush_range+0x5d/0x250<br /> intel_iommu_tlb_sync+0x29/0x40<br /> intel_iommu_unmap_pages+0xfe/0x160<br /> __iommu_unmap+0xd8/0x1a0<br /> vfio_unmap_unpin+0x182/0x340 [vfio_iommu_type1]<br /> vfio_remove_dma+0x2a/0xb0 [vfio_iommu_type1]<br /> vfio_iommu_type1_ioctl+0xafa/0x18e0 [vfio_iommu_type1]<br /> <br /> Move cache_tag_unassign_domain() before iommu_disable_pci_caps() to fix<br /> it.