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{
"id": "CVE-2021-47280",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2024-05-21T15:15:16.277",
"lastModified": "2024-05-21T16:54:26.047",
"vulnStatus": "Awaiting Analysis",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm: Fix use-after-free read in drm_getunique()\n\nThere is a time-of-check-to-time-of-use error in drm_getunique() due\nto retrieving file_priv->master prior to locking the device's master\nmutex.\n\nAn example can be seen in the crash report of the use-after-free error\nfound by Syzbot:\nhttps://syzkaller.appspot.com/bug?id=148d2f1dfac64af52ffd27b661981a540724f803\n\nIn the report, the master pointer was used after being freed. This is\nbecause another process had acquired the device's master mutex in\ndrm_setmaster_ioctl(), then overwrote fpriv->master in\ndrm_new_set_master(). The old value of fpriv->master was subsequently\nfreed before the mutex was unlocked.\n\nTo fix this, we lock the device's master mutex before retrieving the\npointer from from fpriv->master. This patch passes the Syzbot\nreproducer test."
},
{
"lang": "es",
"value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: drm: corrige la lectura de use after free en drm_getunique(). Hay un error de tiempo de verificaci\u00f3n a tiempo de uso en drm_getunique() debido a la recuperaci\u00f3n de file_priv. ->master antes de bloquear el mutex maestro del dispositivo. Se puede ver un ejemplo en el informe de fallo del error de use after free encontrado por Syzbot: https://syzkaller.appspot.com/bug?id=148d2f1dfac64af52ffd27b661981a540724f803 En el informe, el puntero maestro se utiliz\u00f3 despu\u00e9s de ser liberado. Esto se debe a que otro proceso adquiri\u00f3 el mutex maestro del dispositivo en drm_setmaster_ioctl() y luego sobrescribi\u00f3 fpriv->master en drm_new_set_master(). El antiguo valor de fpriv->master se liber\u00f3 posteriormente antes de que se desbloqueara el mutex. Para solucionar este problema, bloqueamos el mutex maestro del dispositivo antes de recuperar el puntero desde fpriv->master. Este parche pasa la prueba del reproductor Syzbot."
}
],
"metrics": {},
"references": [
{
"url": "https://git.kernel.org/stable/c/17dab9326ff263c62dab1dbac4492e2938a049e4",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/491d52e0078860b33b6c14f0a7ac74ca1b603bd6",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/7d233ba700ceb593905ea82b42dadb4ec8ef85e9",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/b246b4c70c1250e7814f409b243000f9c0bf79a3",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/b436acd1cf7fac0ba987abd22955d98025c80c2b",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/f773f8cccac13c7e7bbd9182e7996c727742488e",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
]
}