CVE-2021-47567 powerpc/32: Fix hardlockup on vmap stack overflow

2024-05-2415:12:54

Linux

github.com

linux kernel

vulnerability resolved

powerpc/32 fix

vmap stack overflow

hardlockup fix

AI Score

6.6

Confidence

Low

EPSS

Percentile

15.5%

SSVC

Exploitation

none

Automatable

Technical Impact

partial

JSON

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

powerpc/32: Fix hardlockup on vmap stack overflow

Since the commit c118c7303ad5 (“powerpc/32: Fix vmap stack - Do not
activate MMU before reading task struct”) a vmap stack overflow
results in a hard lockup. This is because emergency_ctx is still
addressed with its virtual address allthough data MMU is not active
anymore at that time.

Fix it by using a physical address instead.

CNA Affected

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "c118c7303ad5",
        "lessThan": "dfe906da9a1a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c118c7303ad5",
        "lessThan": "c4e3ff8b8b1d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c118c7303ad5",
        "lessThan": "5bb60ea611db",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "arch/powerpc/kernel/head_32.h"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.10"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.10",
        "versionType": "custom"
      },
      {
        "status": "unaffected",
        "version": "5.10.83",
        "versionType": "custom",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.6",
        "versionType": "custom",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "5.16",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "arch/powerpc/kernel/head_32.h"
    ],
    "defaultStatus": "affected"
  }
]