CVE-2021-47069

{"id": "CVE-2021-47069", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.0, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 1.0}]}, "published": "2024-03-01T22:15:46.857", "references": [{"url": "https://git.kernel.org/stable/c/4528c0c323085e645b8765913b4a7fd42cf49b65", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/807fa14536b26803b858da878b643be72952a097", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/a11ddb37bf367e6b5239b95ca759e5389bb46048", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/4528c0c323085e645b8765913b4a7fd42cf49b65", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/807fa14536b26803b858da878b643be72952a097", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/a11ddb37bf367e6b5239b95ca759e5389bb46048", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "CWE-672"}]}], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry\n\ndo_mq_timedreceive calls wq_sleep with a stack local address. The\nsender (do_mq_timedsend) uses this address to later call pipelined_send.\n\nThis leads to a very hard to trigger race where a do_mq_timedreceive\ncall might return and leave do_mq_timedsend to rely on an invalid\naddress, causing the following crash:\n\n RIP: 0010:wake_q_add_safe+0x13/0x60\n Call Trace:\n __x64_sys_mq_timedsend+0x2a9/0x490\n do_syscall_64+0x80/0x680\n entry_SYSCALL_64_after_hwframe+0x44/0xa9\n RIP: 0033:0x7f5928e40343\n\nThe race occurs as:\n\n1. do_mq_timedreceive calls wq_sleep with the address of `struct\n ext_wait_queue` on function stack (aliased as `ewq_addr` here) - it\n holds a valid `struct ext_wait_queue *` as long as the stack has not\n been overwritten.\n\n2. `ewq_addr` gets added to info->e_wait_q[RECV].list in wq_add, and\n do_mq_timedsend receives it via wq_get_first_waiter(info, RECV) to call\n __pipelined_op.\n\n3. Sender calls __pipelined_op::smp_store_release(&this->state,\n STATE_READY). Here is where the race window begins. (`this` is\n `ewq_addr`.)\n\n4. If the receiver wakes up now in do_mq_timedreceive::wq_sleep, it\n will see `state == STATE_READY` and break.\n\n5. do_mq_timedreceive returns, and `ewq_addr` is no longer guaranteed\n to be a `struct ext_wait_queue *` since it was on do_mq_timedreceive's\n stack. (Although the address may not get overwritten until another\n function happens to touch it, which means it can persist around for an\n indefinite time.)\n\n6. do_mq_timedsend::__pipelined_op() still believes `ewq_addr` is a\n `struct ext_wait_queue *`, and uses it to find a task_struct to pass to\n the wake_q_add_safe call. In the lucky case where nothing has\n overwritten `ewq_addr` yet, `ewq_addr->task` is the right task_struct.\n In the unlucky case, __pipelined_op::wake_q_add_safe gets handed a\n bogus address as the receiver's task_struct causing the crash.\n\ndo_mq_timedsend::__pipelined_op() should not dereference `this` after\nsetting STATE_READY, as the receiver counterpart is now free to return.\nChange __pipelined_op to call wake_q_add_safe on the receiver's\ntask_struct returned by get_task_struct, instead of dereferencing `this`\nwhich sits on the receiver's stack.\n\nAs Manfred pointed out, the race potentially also exists in\nipc/msg.c::expunge_all and ipc/sem.c::wake_up_sem_queue_prepare. Fix\nthose in the same way."}, {"lang": "es", "value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: ipc/mqueue, msg, sem: evite confiar en una referencia de pila despu\u00e9s de su vencimiento do_mq_timedreceive llama a wq_sleep con una direcci\u00f3n local de pila. El remitente (do_mq_timedsend) usa esta direcci\u00f3n para luego llamar a pipelined_send. Esto conduce a una ejecuci\u00f3n muy dif\u00edcil de desencadenar en la que una llamada do_mq_timedreceive puede regresar y dejar que do_mq_timedsend dependa de una direcci\u00f3n no v\u00e1lida, lo que provoca el siguiente bloqueo: RIP: 0010:wake_q_add_safe+0x13/0x60 Seguimiento de llamadas: __x64_sys_mq_timedsend+0x2a9/0x490 do_syscall_64+0x80 /0x680 Entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f5928e40343 La ejecuci\u00f3n ocurre como: 1. do_mq_timedreceive llama a wq_sleep con la direcci\u00f3n de `struct ext_wait_queue` en la pila de funciones (alias `ewq_addr` aqu\u00ed): contiene una `struct ext_wait_queue * v\u00e1lida ` siempre y cuando la pila no haya sido sobrescrita. 2. `ewq_addr` se agrega a info->e_wait_q[RECV].list en wq_add, y do_mq_timedsend lo recibe a trav\u00e9s de wq_get_first_waiter(info, RECV) para llamar a __pipelined_op. 3. El remitente llama a __pipelined_op::smp_store_release(&this->state, STATE_READY). Aqu\u00ed es donde comienza la ventana de ejecuci\u00f3n. (`esto` es `ewq_addr`.) 4. Si el receptor se activa ahora en do_mq_timedreceive::wq_sleep, ver\u00e1 `state == STATE_READY` y se interrumpir\u00e1. 5. do_mq_timedreceive regresa y ya no se garantiza que `ewq_addr` sea una `struct ext_wait_queue *` ya que estaba en la pila de do_mq_timedreceive. (Aunque es posible que la direcci\u00f3n no se sobrescriba hasta que otra funci\u00f3n la toque, lo que significa que puede persistir por un tiempo indefinido). 6. do_mq_timedsend::__pipelined_op() todav\u00eda cree que `ewq_addr` es una `struct ext_wait_queue *`, y lo usa para encontrar una task_struct para pasar a la llamada wake_q_add_safe. En el afortunado caso de que nada haya sobrescrito `ewq_addr` todav\u00eda, `ewq_addr->task` es la estructura de tarea correcta. En el desafortunado caso, __pipelined_op::wake_q_add_safe recibe una direcci\u00f3n falsa como la task_struct del receptor que causa el bloqueo. do_mq_timedsend::__pipelined_op() no debe eliminar la referencia a \"esto\" despu\u00e9s de configurar STATE_READY, ya que la contraparte del receptor ahora puede regresar. Cambie __pipelined_op para llamar a wake_q_add_safe en el task_struct del receptor devuelto por get_task_struct, en lugar de desreferenciar \"this\" que se encuentra en la pila del receptor. Como se\u00f1al\u00f3 Manfred, la ejecuci\u00f3n tambi\u00e9n existe potencialmente en ipc/msg.c::expunge_all e ipc/sem.c::wake_up_sem_queue_prepare. Arr\u00e9glelos de la misma manera."}], "lastModified": "2025-01-09T18:21:01.560", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "CC04C860-B3F3-4630-B20D-99BEA8F2A42A", "versionEndExcluding": "5.10.40", "versionStartIncluding": "5.6"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "E8F2CE30-38B0-4716-B12B-A139B0F9C5C9", "versionEndExcluding": "5.12.7", "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"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}