CVE-2024-44965 x86/mm: Fix pti_clone_pgtable() alignment assumption

2024-09-0418:36:02

Linux

www.cve.org

linux kernel

vulnerability fix

x86/mm

pti_clone_pgtable

alignment assumption

guenter

i386

pmd aligned

EPSS

Percentile

13.7%

JSON

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

x86/mm: Fix pti_clone_pgtable() alignment assumption

Guenter reported dodgy crashes on an i386-nosmp build using GCC-11
that had the form of endless traps until entry stack exhaust and then
#DF from the stack guard.

It turned out that pti_clone_pgtable() had alignment assumptions on
the start address, notably it hard assumes start is PMD aligned. This
is true on x86_64, but very much not true on i386.

These assumptions can cause the end condition to malfunction, leading
to a ‘short’ clone. Guess what happens when the user mapping has a
short copy of the entry text?

Use the correct increment form for addr to avoid alignment
assumptions.

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "arch/x86/mm/pti.c"
    ],
    "versions": [
      {
        "version": "16a3fe634f6a",
        "lessThan": "18da1b27ce16",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "16a3fe634f6a",
        "lessThan": "25a727233a40",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "16a3fe634f6a",
        "lessThan": "d00c9b4bbc44",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "16a3fe634f6a",
        "lessThan": "4d143ae78200",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "16a3fe634f6a",
        "lessThan": "5c580c1050bc",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "16a3fe634f6a",
        "lessThan": "ca07aab70dd3",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "16a3fe634f6a",
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        "versionType": "git"
      },
      {
        "version": "16a3fe634f6a",
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        "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/mm/pti.c"
    ],
    "versions": [
      {
        "version": "4.19",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "4.19",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.19.320",
        "lessThanOrEqual": "4.19.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.4.282",
        "lessThanOrEqual": "5.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.224",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.15.165",
        "lessThanOrEqual": "5.15.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.1.105",
        "lessThanOrEqual": "6.1.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.6.46",
        "lessThanOrEqual": "6.6.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.10.5",
        "lessThanOrEqual": "6.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.11",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]