fkie_cve-2024-42293
Vulnerability from fkie_nvd
Published
2024-08-17 09:15
Modified
2024-08-19 12:59
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: arm64: mm: Fix lockless walks with static and dynamic page-table folding Lina reports random oopsen originating from the fast GUP code when 16K pages are used with 4-level page-tables, the fourth level being folded at runtime due to lack of LPA2. In this configuration, the generic implementation of p4d_offset_lockless() will return a 'p4d_t *' corresponding to the 'pgd_t' allocated on the stack of the caller, gup_fast_pgd_range(). This is normally fine, but when the fourth level of page-table is folded at runtime, pud_offset_lockless() will offset from the address of the 'p4d_t' to calculate the address of the PUD in the same page-table page. This results in a stray stack read when the 'p4d_t' has been allocated on the stack and can send the walker into the weeds. Fix the problem by providing our own definition of p4d_offset_lockless() when CONFIG_PGTABLE_LEVELS <= 4 which returns the real page-table pointer rather than the address of the local stack variable.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/36639013b3462c06ff8e3400a427f775b4fc97f5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/78672d49d3eebbcda3589f4d6e589caf357c5a59
Impacted products
Vendor Product Version


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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\narm64: mm: Fix lockless walks with static and dynamic page-table folding\n\nLina reports random oopsen originating from the fast GUP code when\n16K pages are used with 4-level page-tables, the fourth level being\nfolded at runtime due to lack of LPA2.\n\nIn this configuration, the generic implementation of\np4d_offset_lockless() will return a \u0027p4d_t *\u0027 corresponding to the\n\u0027pgd_t\u0027 allocated on the stack of the caller, gup_fast_pgd_range().\nThis is normally fine, but when the fourth level of page-table is folded\nat runtime, pud_offset_lockless() will offset from the address of the\n\u0027p4d_t\u0027 to calculate the address of the PUD in the same page-table page.\nThis results in a stray stack read when the \u0027p4d_t\u0027 has been allocated\non the stack and can send the walker into the weeds.\n\nFix the problem by providing our own definition of p4d_offset_lockless()\nwhen CONFIG_PGTABLE_LEVELS \u003c= 4 which returns the real page-table\npointer rather than the address of the local stack variable."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: arm64: mm: corrige recorridos sin bloqueo con plegado de tablas de p\u00e1ginas est\u00e1ticas y din\u00e1micas. Lina informa oopsen aleatorios que se originan en el c\u00f3digo GUP r\u00e1pido cuando se utilizan p\u00e1ginas de 16 KB con tablas de p\u00e1ginas de 4 niveles. el cuarto nivel se pliega en tiempo de ejecuci\u00f3n debido a la falta de LPA2. En esta configuraci\u00f3n, la implementaci\u00f3n gen\u00e9rica de p4d_offset_lockless() devolver\u00e1 un \u0027p4d_t *\u0027 correspondiente al \u0027pgd_t\u0027 asignado en la pila de la persona que llama, gup_fast_pgd_range(). Esto normalmente est\u00e1 bien, pero cuando el cuarto nivel de la tabla de p\u00e1ginas se pliega en tiempo de ejecuci\u00f3n, pud_offset_lockless() se desplazar\u00e1 de la direcci\u00f3n de \u0027p4d_t\u0027 para calcular la direcci\u00f3n del PUD en la misma p\u00e1gina de la tabla de p\u00e1ginas. Esto da como resultado una lectura de pila perdida cuando el \u0027p4d_t\u0027 se ha asignado en la pila y puede enviar al caminante hacia la maleza. Solucione el problema proporcionando nuestra propia definici\u00f3n de p4d_offset_lockless() cuando CONFIG_PGTABLE_LEVELS \u0026lt;= 4, que devuelve el puntero de la tabla de p\u00e1ginas real en lugar de la direcci\u00f3n de la variable de pila local."
    }
  ],
  "id": "CVE-2024-42293",
  "lastModified": "2024-08-19T12:59:59.177",
  "metrics": {},
  "published": "2024-08-17T09:15:09.867",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/36639013b3462c06ff8e3400a427f775b4fc97f5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/78672d49d3eebbcda3589f4d6e589caf357c5a59"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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