CVE-2021-47069 (GCVE-0-2021-47069)
Vulnerability from cvelistv5
Published
2024-03-01 21:15
Modified
2025-05-04 07:03
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry do_mq_timedreceive calls wq_sleep with a stack local address. The sender (do_mq_timedsend) uses this address to later call pipelined_send. This leads to a very hard to trigger race where a do_mq_timedreceive call might return and leave do_mq_timedsend to rely on an invalid address, causing the following crash: RIP: 0010:wake_q_add_safe+0x13/0x60 Call Trace: __x64_sys_mq_timedsend+0x2a9/0x490 do_syscall_64+0x80/0x680 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f5928e40343 The race occurs as: 1. do_mq_timedreceive calls wq_sleep with the address of `struct ext_wait_queue` on function stack (aliased as `ewq_addr` here) - it holds a valid `struct ext_wait_queue *` as long as the stack has not been overwritten. 2. `ewq_addr` gets added to info->e_wait_q[RECV].list in wq_add, and do_mq_timedsend receives it via wq_get_first_waiter(info, RECV) to call __pipelined_op. 3. Sender calls __pipelined_op::smp_store_release(&this->state, STATE_READY). Here is where the race window begins. (`this` is `ewq_addr`.) 4. If the receiver wakes up now in do_mq_timedreceive::wq_sleep, it will see `state == STATE_READY` and break. 5. do_mq_timedreceive returns, and `ewq_addr` is no longer guaranteed to be a `struct ext_wait_queue *` since it was on do_mq_timedreceive's stack. (Although the address may not get overwritten until another function happens to touch it, which means it can persist around for an indefinite time.) 6. do_mq_timedsend::__pipelined_op() still believes `ewq_addr` is a `struct ext_wait_queue *`, and uses it to find a task_struct to pass to the wake_q_add_safe call. In the lucky case where nothing has overwritten `ewq_addr` yet, `ewq_addr->task` is the right task_struct. In the unlucky case, __pipelined_op::wake_q_add_safe gets handed a bogus address as the receiver's task_struct causing the crash. do_mq_timedsend::__pipelined_op() should not dereference `this` after setting STATE_READY, as the receiver counterpart is now free to return. Change __pipelined_op to call wake_q_add_safe on the receiver's task_struct returned by get_task_struct, instead of dereferencing `this` which sits on the receiver's stack. As Manfred pointed out, the race potentially also exists in ipc/msg.c::expunge_all and ipc/sem.c::wake_up_sem_queue_prepare. Fix those in the same way.
References
Impacted products
Vendor Product Version
Linux Linux Version: c5b2cbdbdac563f46ecd5e187253ab1abbd6fc04
Version: c5b2cbdbdac563f46ecd5e187253ab1abbd6fc04
Version: c5b2cbdbdac563f46ecd5e187253ab1abbd6fc04
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2021-47069",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-06-21T16:15:09.996738Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2024-06-21T16:15:20.262Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-04T05:24:39.653Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/4528c0c323085e645b8765913b4a7fd42cf49b65"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/807fa14536b26803b858da878b643be72952a097"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/a11ddb37bf367e6b5239b95ca759e5389bb46048"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "ipc/mqueue.c",
            "ipc/msg.c",
            "ipc/sem.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "4528c0c323085e645b8765913b4a7fd42cf49b65",
              "status": "affected",
              "version": "c5b2cbdbdac563f46ecd5e187253ab1abbd6fc04",
              "versionType": "git"
            },
            {
              "lessThan": "807fa14536b26803b858da878b643be72952a097",
              "status": "affected",
              "version": "c5b2cbdbdac563f46ecd5e187253ab1abbd6fc04",
              "versionType": "git"
            },
            {
              "lessThan": "a11ddb37bf367e6b5239b95ca759e5389bb46048",
              "status": "affected",
              "version": "c5b2cbdbdac563f46ecd5e187253ab1abbd6fc04",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "ipc/mqueue.c",
            "ipc/msg.c",
            "ipc/sem.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.6"
            },
            {
              "lessThan": "5.6",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.12.*",
              "status": "unaffected",
              "version": "5.12.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "5.13",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.40",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.12.7",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.13",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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-\u003ee_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(\u0026this-\u003estate,\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\u0027s\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-\u003etask` 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\u0027s 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\u0027s\ntask_struct returned by get_task_struct, instead of dereferencing `this`\nwhich sits on the receiver\u0027s 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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-05-04T07:03:33.104Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/4528c0c323085e645b8765913b4a7fd42cf49b65"
        },
        {
          "url": "https://git.kernel.org/stable/c/807fa14536b26803b858da878b643be72952a097"
        },
        {
          "url": "https://git.kernel.org/stable/c/a11ddb37bf367e6b5239b95ca759e5389bb46048"
        }
      ],
      "title": "ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2021-47069",
    "datePublished": "2024-03-01T21:15:08.598Z",
    "dateReserved": "2024-02-29T22:33:44.296Z",
    "dateUpdated": "2025-05-04T07:03:33.104Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2021-47069\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2024-03-01T22:15:46.857\",\"lastModified\":\"2025-01-09T18:21:01.560\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"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-\u003ee_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(\u0026this-\u003estate,\\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\u0027s\\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-\u003etask` 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\u0027s 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\u0027s\\ntask_struct returned by get_task_struct, instead of dereferencing `this`\\nwhich sits on the receiver\u0027s 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-\u0026gt;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(\u0026amp;this-\u0026gt;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-\u0026gt;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.\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.0,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.0,\"impactScore\":5.9}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-672\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.6\",\"versionEndExcluding\":\"5.10.40\",\"matchCriteriaId\":\"CC04C860-B3F3-4630-B20D-99BEA8F2A42A\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.11\",\"versionEndExcluding\":\"5.12.7\",\"matchCriteriaId\":\"E8F2CE30-38B0-4716-B12B-A139B0F9C5C9\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:*\",\"matchCriteriaId\":\"0CBAD0FC-C281-4666-AB2F-F8E6E1165DF7\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:*\",\"matchCriteriaId\":\"96AC23B2-D46A-49D9-8203-8E1BEDCA8532\"}]}]}],\"references\":[{\"url\":\"https://git.kernel.org/stable/c/4528c0c323085e645b8765913b4a7fd42cf49b65\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/807fa14536b26803b858da878b643be72952a097\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/a11ddb37bf367e6b5239b95ca759e5389bb46048\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/4528c0c323085e645b8765913b4a7fd42cf49b65\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/807fa14536b26803b858da878b643be72952a097\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/a11ddb37bf367e6b5239b95ca759e5389bb46048\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CVE Program Container\", \"references\": [{\"url\": \"https://git.kernel.org/stable/c/4528c0c323085e645b8765913b4a7fd42cf49b65\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/807fa14536b26803b858da878b643be72952a097\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/a11ddb37bf367e6b5239b95ca759e5389bb46048\", \"tags\": [\"x_transferred\"]}], \"providerMetadata\": {\"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\", \"dateUpdated\": \"2024-08-04T05:24:39.653Z\"}}, {\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2021-47069\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2024-06-21T16:15:09.996738Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2024-06-21T16:15:15.682Z\"}}], \"cna\": {\"title\": \"ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry\", \"affected\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"c5b2cbdbdac563f46ecd5e187253ab1abbd6fc04\", \"lessThan\": \"4528c0c323085e645b8765913b4a7fd42cf49b65\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"c5b2cbdbdac563f46ecd5e187253ab1abbd6fc04\", \"lessThan\": \"807fa14536b26803b858da878b643be72952a097\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"c5b2cbdbdac563f46ecd5e187253ab1abbd6fc04\", \"lessThan\": \"a11ddb37bf367e6b5239b95ca759e5389bb46048\", \"versionType\": \"git\"}], \"programFiles\": [\"ipc/mqueue.c\", \"ipc/msg.c\", \"ipc/sem.c\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"5.6\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"5.6\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"5.10.40\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.10.*\"}, {\"status\": \"unaffected\", \"version\": \"5.12.7\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.12.*\"}, {\"status\": \"unaffected\", \"version\": \"5.13\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"ipc/mqueue.c\", \"ipc/msg.c\", \"ipc/sem.c\"], \"defaultStatus\": \"affected\"}], \"references\": [{\"url\": \"https://git.kernel.org/stable/c/4528c0c323085e645b8765913b4a7fd42cf49b65\"}, {\"url\": \"https://git.kernel.org/stable/c/807fa14536b26803b858da878b643be72952a097\"}, {\"url\": \"https://git.kernel.org/stable/c/a11ddb37bf367e6b5239b95ca759e5389bb46048\"}], \"x_generator\": {\"engine\": \"bippy-1.2.0\"}, \"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-\u003ee_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(\u0026this-\u003estate,\\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\u0027s\\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-\u003etask` 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\u0027s 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\u0027s\\ntask_struct returned by get_task_struct, instead of dereferencing `this`\\nwhich sits on the receiver\u0027s 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.\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.10.40\", \"versionStartIncluding\": \"5.6\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.12.7\", \"versionStartIncluding\": \"5.6\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.13\", \"versionStartIncluding\": \"5.6\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2025-05-04T07:03:33.104Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2021-47069\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2025-05-04T07:03:33.104Z\", \"dateReserved\": \"2024-02-29T22:33:44.296Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2024-03-01T21:15:08.598Z\", \"assignerShortName\": \"Linux\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.1"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.