CVE-2021-47282

{"id": "CVE-2021-47282", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "[email protected]", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 1.8}]}, "published": "2024-05-21T15:15:16.430", "references": [{"url": "https://git.kernel.org/stable/c/01415ff85a24308059e06ca3e97fd7bf75648690", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/13817d466eb8713a1ffd254f537402f091d48444", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/82a8ffba54d31e97582051cb56ba1f988018681e", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/b5502580cf958b094f3b69dfe4eece90eae01fbc", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/01415ff85a24308059e06ca3e97fd7bf75648690", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/13817d466eb8713a1ffd254f537402f091d48444", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/82a8ffba54d31e97582051cb56ba1f988018681e", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/b5502580cf958b094f3b69dfe4eece90eae01fbc", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "[email protected]", "description": [{"lang": "en", "value": "CWE-787"}]}], "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."}], "lastModified": "2025-04-30T14:30:12.573", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "6D23A3FF-8CE4-41A1-9E6A-8138FDC413F6", "versionEndExcluding": "5.4.126", "versionStartIncluding": "5.4"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "DA547B08-9D25-467B-AD0D-8460FE4EE70D", "versionEndExcluding": "5.10.44", "versionStartIncluding": "5.5"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "F914A757-FAFD-407E-9031-21F66635D5EA", "versionEndExcluding": "5.12.11", "versionStartIncluding": "5.11"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "0CBAD0FC-C281-4666-AB2F-F8E6E1165DF7"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "96AC23B2-D46A-49D9-8203-8E1BEDCA8532"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "DA610E30-717C-4700-9F77-A3C9244F3BFD"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "1ECD33F5-85BE-430B-8F86-8D7BD560311D"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc5:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "CF351855-2437-4CF5-AD7C-BDFA51F27683"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}