CVE-2021-46977 KVM: VMX: Disable preemption when probing user return MSRs

2024-02-2808:13:08

Linux

github.com

cve-2021-46977

kvm

vmx

vulnerability

linux kernel

6.8 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

15.7%

JSON

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

KVM: VMX: Disable preemption when probing user return MSRs

Disable preemption when probing a user return MSR via RDSMR/WRMSR. If
the MSR holds a different value per logical CPU, the WRMSR could corrupt
the host’s value if KVM is preempted between the RDMSR and WRMSR, and
then rescheduled on a different CPU.

Opportunistically land the helper in common x86, SVM will use the helper
in a future commit.

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "arch/x86/include/asm/kvm_host.h",
      "arch/x86/kvm/vmx/vmx.c",
      "arch/x86/kvm/x86.c"
    ],
    "versions": [
      {
        "version": "4be534102624",
        "lessThan": "31f29749ee97",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "4be534102624",
        "lessThan": "5adcdeb57007",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "4be534102624",
        "lessThan": "e3ea1895df71",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "4be534102624",
        "lessThan": "5104d7ffcf24",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "arch/x86/include/asm/kvm_host.h",
      "arch/x86/kvm/vmx/vmx.c",
      "arch/x86/kvm/x86.c"
    ],
    "versions": [
      {
        "version": "5.5",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "5.5",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.38",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.11.22",
        "lessThanOrEqual": "5.11.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.12.5",
        "lessThanOrEqual": "5.12.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.13",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]