CVE-2024-35996 cpu: Re-enable CPU mitigations by default for !X86 architectures

2024-05-2009:47:59

Linux

github.com

linux kernel

vulnerability

cpu mitigations

architecture

x86

kconfig

mitigations

speculative execution

compile-time

AI Score

Confidence

Low

EPSS

Percentile

10.3%

SSVC

Exploitation

none

Automatable

Technical Impact

partial

JSON

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

cpu: Re-enable CPU mitigations by default for !X86 architectures

Rename x86’s to CPU_MITIGATIONS, define it in generic code, and force it
on for all architectures exception x86. A recent commit to turn
mitigations off by default if SPECULATION_MITIGATIONS=n kinda sorta
missed that “cpu_mitigations” is completely generic, whereas
SPECULATION_MITIGATIONS is x86-specific.

Rename x86’s SPECULATIVE_MITIGATIONS instead of keeping both and have it
select CPU_MITIGATIONS, as having two configs for the same thing is
unnecessary and confusing. This will also allow x86 to use the knob to
manage mitigations that aren’t strictly related to speculative
execution.

Use another Kconfig to communicate to common code that CPU_MITIGATIONS
is already defined instead of having x86’s menu depend on the common
CPU_MITIGATIONS. This allows keeping a single point of contact for all
of x86’s mitigations, and it’s not clear that other architectures want
to allow disabling mitigations at compile-time.

CNA Affected

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "30da4180fd76",
        "lessThan": "af6d6a923b40",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "70688450ddda",
        "lessThan": "36b32816fbab",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9c09773917fb",
        "lessThan": "38f17d1fbb5b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "2978ee7c973c",
        "lessThan": "8292f4f8dd1b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c4a9babdd5d5",
        "lessThan": "fd8547ebc187",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f337a6a21e2f",
        "lessThan": "fe42754b94a4",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "arch/Kconfig",
      "arch/x86/Kconfig",
      "kernel/cpu.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.15.156",
        "lessThan": "5.15.158",
        "versionType": "custom"
      },
      {
        "status": "affected",
        "version": "6.1.87",
        "lessThan": "6.1.90",
        "versionType": "custom"
      },
      {
        "status": "affected",
        "version": "6.6.28",
        "lessThan": "6.6.30",
        "versionType": "custom"
      },
      {
        "status": "affected",
        "version": "6.8.7",
        "lessThan": "6.8.9",
        "versionType": "custom"
      }
    ],
    "programFiles": [
      "arch/Kconfig",
      "arch/x86/Kconfig",
      "kernel/cpu.c"
    ],
    "defaultStatus": "unaffected"
  }
]