2024-12-08 03:06:42 +00:00

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{
"id": "CVE-2021-47221",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2024-05-21T15:15:11.380",
"lastModified": "2024-11-21T06:35:39.267",
"vulnStatus": "Awaiting Analysis",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/slub: actually fix freelist pointer vs redzoning\n\nIt turns out that SLUB redzoning (\"slub_debug=Z\") checks from\ns->object_size rather than from s->inuse (which is normally bumped to\nmake room for the freelist pointer), so a cache created with an object\nsize less than 24 would have the freelist pointer written beyond\ns->object_size, causing the redzone to be corrupted by the freelist\npointer. This was very visible with \"slub_debug=ZF\":\n\n BUG test (Tainted: G B ): Right Redzone overwritten\n -----------------------------------------------------------------------------\n\n INFO: 0xffff957ead1c05de-0xffff957ead1c05df @offset=1502. First byte 0x1a instead of 0xbb\n INFO: Slab 0xffffef3950b47000 objects=170 used=170 fp=0x0000000000000000 flags=0x8000000000000200\n INFO: Object 0xffff957ead1c05d8 @offset=1496 fp=0xffff957ead1c0620\n\n Redzone (____ptrval____): bb bb bb bb bb bb bb bb ........\n Object (____ptrval____): 00 00 00 00 00 f6 f4 a5 ........\n Redzone (____ptrval____): 40 1d e8 1a aa @....\n Padding (____ptrval____): 00 00 00 00 00 00 00 00 ........\n\nAdjust the offset to stay within s->object_size.\n\n(Note that no caches of in this size range are known to exist in the\nkernel currently.)"
},
{
"lang": "es",
"value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: mm/slub: en realidad corrige el puntero de lista libre frente a redzoning. Resulta que SLUB redzoning (\"slub_debug=Z\") verifica desde s->object_size en lugar de s->inuse (que normalmente se elimina para dejar espacio para el puntero de lista libre), por lo que un cach\u00e9 creado con un tama\u00f1o de objeto menor a 24 tendr\u00eda el puntero de lista libre escrito m\u00e1s all\u00e1 de s->object_size, causando que el puntero de lista libre corrompa la zona roja. Esto fue muy visible con \"slub_debug=ZF\": prueba de BUG(contaminada: GB): zona roja derecha sobrescrita ---------------------------- ------------------------------------------------- INFORMACI\u00d3N : 0xffff957ead1c05de-0xffff957ead1c05df @offset=1502. Primer byte 0x1a en lugar de 0xbb INFORMACI\u00d3N: slab 0xffffef3950b47000 objetos=170 usados=170 fp=0x0000000000000000 banderas=0x80000000000000200 INFORMACI\u00d3N: Objeto 0xffff957ead1c05d8 @offset=1496 fp=0xffff9 57ead1c0620 Zona roja (____ptrval____): bb bb bb bb bb bb bb bb .... .... Objeto (____ptrval____): 00 00 00 00 00 f6 f4 a5 ........ Redzone (____ptrval____): 40 1d e8 1a aa @.... Relleno (____ptrval____): 00 00 00 00 00 00 00 00 ........ Ajuste el desplazamiento para permanecer dentro de s->object_size. (Tenga en cuenta que actualmente no se sabe que existan cach\u00e9s de este rango de tama\u00f1o en el kernel)."
}
],
"metrics": {},
"references": [
{
"url": "https://git.kernel.org/stable/c/ce6e8bee7a3883e8008b30f5887dbb426aac6a35",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/e41a49fadbc80b60b48d3c095d9e2ee7ef7c9a8e",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/f6ed2357541612a13a5841b3af4dc32ed984a25f",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/ce6e8bee7a3883e8008b30f5887dbb426aac6a35",
"source": "af854a3a-2127-422b-91ae-364da2661108"
},
{
"url": "https://git.kernel.org/stable/c/e41a49fadbc80b60b48d3c095d9e2ee7ef7c9a8e",
"source": "af854a3a-2127-422b-91ae-364da2661108"
},
{
"url": "https://git.kernel.org/stable/c/f6ed2357541612a13a5841b3af4dc32ed984a25f",
"source": "af854a3a-2127-422b-91ae-364da2661108"
}
]
}