CVE-2021-47140
- Source
- https://nvd.nist.gov/vuln/detail/CVE-2021-47140
- Import Source
- https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2021-47140.json
- JSON Data
- https://api.test.osv.dev/v1/vulns/CVE-2021-47140
- Downstream
- Published
- 2024-03-25T09:15:08Z
- Modified
- 2025-08-09T20:01:28Z
- Summary
- [none]
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
iommu/amd: Clear DMA ops when switching domain
Since commit 08a27c1c3ecf ("iommu: Add support to change default domain of an iommu group") a user can switch a device between IOMMU and direct DMA through sysfs. This doesn't work for AMD IOMMU at the moment because dev->dma_ops is not cleared when switching from a DMA to an identity IOMMU domain. The DMA layer thus attempts to use the dma-iommu ops on an identity domain, causing an oops:
# echo 0000:00:05.0 > /sys/sys/bus/pci/drivers/e1000e/unbind # echo identity > /sys/bus/pci/devices/0000:00:05.0/iommugroup/type # echo 0000:00:05.0 > /sys/sys/bus/pci/drivers/e1000e/bind ... BUG: kernel NULL pointer dereference, address: 0000000000000028 ... Call Trace: iommudmaalloc e1000esetuptxresources e1000e_open
Since iommuchangedevdefdomain() calls probefinalize() again, clear the dmaops there like Vt-d does.
- References