CVE-2022-48894

In the Linux kernel, the following vulnerability has been resolved:

iommu/arm-smmu-v3: Dont unregister on shutdown

Similar to SMMUv2, this driver calls iommu_device_unregister() from the shutdown path, which removes the IOMMU groups with no coordination whatsoever with their users - shutdown methods are optional in device drivers. This can lead to NULL pointer dereferences in those drivers DMA API calls, or worse.

Instead of calling the full arm_smmu_device_remove() from arm_smmu_device_shutdown(), lets pick only the relevant function call - arm_smmu_device_disable() - more or less the reverse of arm_smmu_device_reset() - and call just that from the shutdown path.

Weakness

A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/32ea2c57dc216b6ad8125fa680d31daa5d421c95
• https://git.kernel.org/stable/c/ead3e6c79479890444c777fd329afc125fecde48