NULL Pointer Dereference Affecting kernel package, versions *
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Test your applications- Snyk ID SNYK-CENTOS7-KERNEL-6498748
- published 26 Mar 2024
- disclosed 25 Mar 2024
Introduced: 25 Mar 2024
CVE-2021-47140 Open this link in a new tabHow to fix?
There is no fixed version for Centos:7 kernel.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel package and not the kernel package as distributed by Centos.
See How to fix? for Centos:7 relevant fixed versions and status.
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/iommu_group/type
echo 0000:00:05.0 > /sys/sys/bus/pci/drivers/e1000e/bind
... BUG: kernel NULL pointer dereference, address: 0000000000000028 ... Call Trace: iommu_dma_alloc e1000e_setup_tx_resources e1000e_open
Since iommu_change_dev_def_domain() calls probe_finalize() again, clear the dma_ops there like Vt-d does.