CVE-2024-42293

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.

CVSS

No CVSS.

References

Link	Resource
https://git.kernel.org/stable/c/36639013b3462c06ff8e3400a427f775b4fc97f5
https://git.kernel.org/stable/c/78672d49d3eebbcda3589f4d6e589caf357c5a59

Configurations

No configuration.

History

No history.

Information

Published : 2024-08-17 09:15

Updated : 2024-08-19 12:59

NVD link : CVE-2024-42293

Mitre link : CVE-2024-42293

CVE.ORG link : CVE-2024-42293

JSON object : View

Products Affected

No product.

CWE

No CWE.

{"id": "CVE-2024-42293", "cveTags": [], "metrics": {}, "published": "2024-08-17T09:15:09.867", "references": [{"url": "https://git.kernel.org/stable/c/36639013b3462c06ff8e3400a427f775b4fc97f5", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/78672d49d3eebbcda3589f4d6e589caf357c5a59", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "vulnStatus": "Awaiting Analysis", "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 'p4d_t *' corresponding to the\n'pgd_t' 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'p4d_t' to calculate the address of the PUD in the same page-table page.\nThis results in a stray stack read when the 'p4d_t' 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 <= 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 'p4d_t *' correspondiente al 'pgd_t' 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 'p4d_t' 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 'p4d_t' 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 <= 4, que devuelve el puntero de la tabla de p\u00e1ginas real en lugar de la direcci\u00f3n de la variable de pila local."}], "lastModified": "2024-08-19T12:59:59.177", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}