CVE-2021-47112 x86/kvm: Teardown PV features on boot CPU as well

2024-03-1520:14:20

Linux

github.com

cve-2021-47112

linux kernel

x86/kvm

teardown pv features

boot cpu

hypervisor

hibernation

memory

security vulnerability

AI Score

6.8

Confidence

Low

EPSS

Percentile

15.5%

SSVC

Exploitation

none

Automatable

Technical Impact

partial

JSON

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

x86/kvm: Teardown PV features on boot CPU as well

Various PV features (Async PF, PV EOI, steal time) work through memory
shared with hypervisor and when we restore from hibernation we must
properly teardown all these features to make sure hypervisor doesn’t
write to stale locations after we jump to the previously hibernated kernel
(which can try to place anything there). For secondary CPUs the job is
already done by kvm_cpu_down_prepare(), register syscore ops to do
the same for boot CPU.

CNA Affected

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "1da177e4c3f4",
        "lessThan": "7620a669111b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f4",
        "lessThan": "38b858da1c58",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f4",
        "lessThan": "d1629b5b925d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f4",
        "lessThan": "8b79feffeca2",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "arch/x86/kernel/kvm.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "unaffected",
        "version": "5.4.125",
        "versionType": "custom",
        "lessThanOrEqual": "5.4.*"
      },
      {
        "status": "unaffected",
        "version": "5.10.43",
        "versionType": "custom",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.12.10",
        "versionType": "custom",
        "lessThanOrEqual": "5.12.*"
      },
      {
        "status": "unaffected",
        "version": "5.13",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "arch/x86/kernel/kvm.c"
    ],
    "defaultStatus": "affected"
  }
]