nvd-json-data-feeds/CVE-2021/CVE-2021-472xx/CVE-2021-47282.json

{
  "id": "CVE-2021-47282",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2024-05-21T15:15:16.430",
  "lastModified": "2024-11-21T06:35:47.563",
  "vulnStatus": "Awaiting Analysis",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nspi: bcm2835: Fix out-of-bounds access with more than 4 slaves\n\nCommit 571e31fa60b3 (\"spi: bcm2835: Cache CS register value for\n->prepare_message()\") limited the number of slaves to 3 at compile-time.\nThe limitation was necessitated by a statically-sized array prepare_cs[]\nin the driver private data which contains a per-slave register value.\n\nThe commit sought to enforce the limitation at run-time by setting the\ncontroller's num_chipselect to 3:  Slaves with a higher chipselect are\nrejected by spi_add_device().\n\nHowever the commit neglected that num_chipselect only limits the number\nof *native* chipselects.  If GPIO chipselects are specified in the\ndevice tree for more than 3 slaves, num_chipselect is silently raised by\nof_spi_get_gpio_numbers() and the result are out-of-bounds accesses to\nthe statically-sized array prepare_cs[].\n\nAs a bandaid fix which is backportable to stable, raise the number of\nallowed slaves to 24 (which \"ought to be enough for anybody\"), enforce\nthe limitation on slave ->setup and revert num_chipselect to 3 (which is\nthe number of native chipselects supported by the controller).\nAn upcoming for-next commit will allow an arbitrary number of slaves."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: spi: bcm2835: corrige el acceso fuera de los l\u00edmites con m\u00e1s de 4 esclavos. La confirmaci\u00f3n 571e31fa60b3 (\"spi: bcm2835: valor de registro CS de cach\u00e9 para ->prepare_message()\") limit\u00f3 el n\u00famero de esclavos a 3 en tiempo de compilaci\u00f3n. La limitaci\u00f3n fue necesaria por una matriz de tama\u00f1o est\u00e1tico prepare_cs[] en los datos privados del controlador que contiene un valor de registro por esclavo. La confirmaci\u00f3n buscaba hacer cumplir la limitaci\u00f3n en tiempo de ejecuci\u00f3n estableciendo num_chipselect del controlador en 3: spi_add_device() rechaza los esclavos con una selecci\u00f3n de chip m\u00e1s alta. Sin embargo, la confirmaci\u00f3n omiti\u00f3 que num_chipselect solo limita el n\u00famero de selecciones de chips *nativas*. Si se especifican selecciones de chips GPIO en el \u00e1rbol de dispositivos para m\u00e1s de 3 esclavos, of_spi_get_gpio_numbers() genera silenciosamente num_chipselect y el resultado son accesos fuera de los l\u00edmites a la matriz de tama\u00f1o est\u00e1tico prepare_cs[]. Como soluci\u00f3n curita que se puede volver a transferir a estable, aumente la cantidad de esclavos permitidos a 24 (lo que \"deber\u00eda ser suficiente para cualquiera\"), aplique la limitaci\u00f3n en esclavo -> configuraci\u00f3n y revierta num_chipselect a 3 (que es la cantidad de nativos selecciones de chips admitidas por el controlador). Una pr\u00f3xima confirmaci\u00f3n para la pr\u00f3xima permitir\u00e1 una cantidad arbitraria de esclavos."
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/01415ff85a24308059e06ca3e97fd7bf75648690",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/13817d466eb8713a1ffd254f537402f091d48444",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/82a8ffba54d31e97582051cb56ba1f988018681e",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/b5502580cf958b094f3b69dfe4eece90eae01fbc",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/01415ff85a24308059e06ca3e97fd7bf75648690",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://git.kernel.org/stable/c/13817d466eb8713a1ffd254f537402f091d48444",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://git.kernel.org/stable/c/82a8ffba54d31e97582051cb56ba1f988018681e",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://git.kernel.org/stable/c/b5502580cf958b094f3b69dfe4eece90eae01fbc",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ]
}