CVE-2021-47140

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description A vulnerability has been resolved in the Linux kernel related to the iommu/amd component. The issue occurs when switching a device between IOMMU and direct DMA through sysfs, which does not work for AMD IOMMU because dev->dma ops is not cleared when switching from a DMA to an identity IOMMU domain. This causes the DMA layer to attempt to use the dma-iommu ops on an identity domain, resulting in a kernel NULL pointer dereference. The vulnerability can be triggered by a series of commands, including echoing "identity" to /sys/bus/pci/devices/0000:00:05.0/iommu group/type and then binding the device to the e1000e driver. The iommu dma alloc, e1000e setup tx resources, and e1000e open functions are involved in the call trace.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.