CVE-2021-46971

2024-02-2719:04:07

Linux

web.nvd.nist.gov

4698

cve

2021

46971

linux kernel

perf

core

vulnerability

fix

security

selinux

lockdown

lsm

selinux

access control

nvd

AI Score

6.4

Confidence

Low

EPSS

Percentile

15.5%

JSON

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

perf/core: Fix unconditional security_locked_down() call

Currently, the lockdown state is queried unconditionally, even though
its result is used only if the PERF_SAMPLE_REGS_INTR bit is set in
attr.sample_type. While that doesn’t matter in case of the Lockdown LSM,
it causes trouble with the SELinux’s lockdown hook implementation.

SELinux implements the locked_down hook with a check whether the current
task’s type has the corresponding “lockdown” class permission
(“integrity” or “confidentiality”) allowed in the policy. This means
that calling the hook when the access control decision would be ignored
generates a bogus permission check and audit record.

Fix this by checking sample_type first and only calling the hook when
its result would be honored.

Affected configurations

Vulners

Node

linuxlinux_kernelRange5.4–5.4.117

linuxlinux_kernelRange5.5.0–5.10.35

linuxlinux_kernelRange5.11.0–5.11.19

linuxlinux_kernelRange5.12.0–5.12.2

linuxlinux_kernelRange5.13.0≥

VendorProductVersionCPE
linuxlinux_kernel*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

Vendor	Product	Version	CPE
linux	linux_kernel	*	cpe:2.3:o:linux:linux_kernel::::::::

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "kernel/events/core.c"
    ],
    "versions": [
      {
        "version": "b0c8fdc7fdb7",
        "lessThan": "b246759284d6",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "b0c8fdc7fdb7",
        "lessThan": "4348d3b5027b",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "b0c8fdc7fdb7",
        "lessThan": "f5809ca4c311",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "b0c8fdc7fdb7",
        "lessThan": "c7b0208ee370",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "b0c8fdc7fdb7",
        "lessThan": "08ef1af4de5f",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "kernel/events/core.c"
    ],
    "versions": [
      {
        "version": "5.4",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "5.4",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.4.117",
        "lessThanOrEqual": "5.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.35",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.11.19",
        "lessThanOrEqual": "5.11.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.12.2",
        "lessThanOrEqual": "5.12.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.13",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]