FKIE_CVE-2024-41010

Vulnerability from fkie_nvd - Published: 2024-07-17 07:15 - Updated: 2024-11-21 09:32
Severity ?
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix too early release of tcx_entry Pedro Pinto and later independently also Hyunwoo Kim and Wongi Lee reported an issue that the tcx_entry can be released too early leading to a use after free (UAF) when an active old-style ingress or clsact qdisc with a shared tc block is later replaced by another ingress or clsact instance. Essentially, the sequence to trigger the UAF (one example) can be as follows: 1. A network namespace is created 2. An ingress qdisc is created. This allocates a tcx_entry, and &tcx_entry->miniq is stored in the qdisc's miniqp->p_miniq. At the same time, a tcf block with index 1 is created. 3. chain0 is attached to the tcf block. chain0 must be connected to the block linked to the ingress qdisc to later reach the function tcf_chain0_head_change_cb_del() which triggers the UAF. 4. Create and graft a clsact qdisc. This causes the ingress qdisc created in step 1 to be removed, thus freeing the previously linked tcx_entry: rtnetlink_rcv_msg() => tc_modify_qdisc() => qdisc_create() => clsact_init() [a] => qdisc_graft() => qdisc_destroy() => __qdisc_destroy() => ingress_destroy() [b] => tcx_entry_free() => kfree_rcu() // tcx_entry freed 5. Finally, the network namespace is closed. This registers the cleanup_net worker, and during the process of releasing the remaining clsact qdisc, it accesses the tcx_entry that was already freed in step 4, causing the UAF to occur: cleanup_net() => ops_exit_list() => default_device_exit_batch() => unregister_netdevice_many() => unregister_netdevice_many_notify() => dev_shutdown() => qdisc_put() => clsact_destroy() [c] => tcf_block_put_ext() => tcf_chain0_head_change_cb_del() => tcf_chain_head_change_item() => clsact_chain_head_change() => mini_qdisc_pair_swap() // UAF There are also other variants, the gist is to add an ingress (or clsact) qdisc with a specific shared block, then to replace that qdisc, waiting for the tcx_entry kfree_rcu() to be executed and subsequently accessing the current active qdisc's miniq one way or another. The correct fix is to turn the miniq_active boolean into a counter. What can be observed, at step 2 above, the counter transitions from 0->1, at step [a] from 1->2 (in order for the miniq object to remain active during the replacement), then in [b] from 2->1 and finally [c] 1->0 with the eventual release. The reference counter in general ranges from [0,2] and it does not need to be atomic since all access to the counter is protected by the rtnl mutex. With this in place, there is no longer a UAF happening and the tcx_entry is freed at the correct time.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1cb6f0bae50441f4b4b32a28315853b279c7404eMailing List, Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/230bb13650b0f186f540500fd5f5f7096a822a2aMailing List, Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f61ecf1bd5b562ebfd7d430ccb31619857e80857Mailing List, Patch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/1cb6f0bae50441f4b4b32a28315853b279c7404eMailing List, Patch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/230bb13650b0f186f540500fd5f5f7096a822a2aMailing List, Patch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/f61ecf1bd5b562ebfd7d430ccb31619857e80857Mailing List, Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
To clipboard 

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "BBD7DB8F-6881-4008-B9ED-5588CD8061D9",
              "versionEndExcluding": "6.6.41",
              "versionStartIncluding": "6.6",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "AB2E8DEC-CFD5-4C2B-981D-E7E45A36C352",
              "versionEndExcluding": "6.9.10",
              "versionStartIncluding": "6.7",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix too early release of tcx_entry\n\nPedro Pinto and later independently also Hyunwoo Kim and Wongi Lee reported\nan issue that the tcx_entry can be released too early leading to a use\nafter free (UAF) when an active old-style ingress or clsact qdisc with a\nshared tc block is later replaced by another ingress or clsact instance.\n\nEssentially, the sequence to trigger the UAF (one example) can be as follows:\n\n  1. A network namespace is created\n  2. An ingress qdisc is created. This allocates a tcx_entry, and\n     \u0026tcx_entry-\u003eminiq is stored in the qdisc\u0027s miniqp-\u003ep_miniq. At the\n     same time, a tcf block with index 1 is created.\n  3. chain0 is attached to the tcf block. chain0 must be connected to\n     the block linked to the ingress qdisc to later reach the function\n     tcf_chain0_head_change_cb_del() which triggers the UAF.\n  4. Create and graft a clsact qdisc. This causes the ingress qdisc\n     created in step 1 to be removed, thus freeing the previously linked\n     tcx_entry:\n\n     rtnetlink_rcv_msg()\n       =\u003e tc_modify_qdisc()\n         =\u003e qdisc_create()\n           =\u003e clsact_init() [a]\n         =\u003e qdisc_graft()\n           =\u003e qdisc_destroy()\n             =\u003e __qdisc_destroy()\n               =\u003e ingress_destroy() [b]\n                 =\u003e tcx_entry_free()\n                   =\u003e kfree_rcu() // tcx_entry freed\n\n  5. Finally, the network namespace is closed. This registers the\n     cleanup_net worker, and during the process of releasing the\n     remaining clsact qdisc, it accesses the tcx_entry that was\n     already freed in step 4, causing the UAF to occur:\n\n     cleanup_net()\n       =\u003e ops_exit_list()\n         =\u003e default_device_exit_batch()\n           =\u003e unregister_netdevice_many()\n             =\u003e unregister_netdevice_many_notify()\n               =\u003e dev_shutdown()\n                 =\u003e qdisc_put()\n                   =\u003e clsact_destroy() [c]\n                     =\u003e tcf_block_put_ext()\n                       =\u003e tcf_chain0_head_change_cb_del()\n                         =\u003e tcf_chain_head_change_item()\n                           =\u003e clsact_chain_head_change()\n                             =\u003e mini_qdisc_pair_swap() // UAF\n\nThere are also other variants, the gist is to add an ingress (or clsact)\nqdisc with a specific shared block, then to replace that qdisc, waiting\nfor the tcx_entry kfree_rcu() to be executed and subsequently accessing\nthe current active qdisc\u0027s miniq one way or another.\n\nThe correct fix is to turn the miniq_active boolean into a counter. What\ncan be observed, at step 2 above, the counter transitions from 0-\u003e1, at\nstep [a] from 1-\u003e2 (in order for the miniq object to remain active during\nthe replacement), then in [b] from 2-\u003e1 and finally [c] 1-\u003e0 with the\neventual release. The reference counter in general ranges from [0,2] and\nit does not need to be atomic since all access to the counter is protected\nby the rtnl mutex. With this in place, there is no longer a UAF happening\nand the tcx_entry is freed at the correct time."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: bpf: Se solucion\u00f3 el lanzamiento demasiado temprano de tcx_entry Pedro Pinto y m\u00e1s tarde, de forma independiente, tambi\u00e9n Hyunwoo Kim y Wongi Lee informaron un problema por el cual tcx_entry se puede lanzar demasiado pronto, lo que lleva a un uso posterior a la liberaci\u00f3n (UAF ) cuando una qdisc ingress o clsact antigua activa con un bloque tc compartido se reemplaza posteriormente por otra instancia de ingress o clsact. Esencialmente, la secuencia para activar la UAF (un ejemplo) puede ser la siguiente: 1. Se crea un espacio de nombres de red. 2. Se crea una qdisc de entrada. Esto asigna un tcx_entry, y \u0026amp;tcx_entry-\u0026gt;miniq se almacena en el miniqp-\u0026gt;p_miniq de la qdisc. Al mismo tiempo, se crea un bloque tcf con \u00edndice 1. 3. chain0 est\u00e1 adjunta al bloque tcf. chain0 debe estar conectado al bloque vinculado a la qdisc de ingreso para luego llegar a la funci\u00f3n tcf_chain0_head_change_cb_del() que activa la UAF. 4. Cree e injerte una qdisc clsact. Esto hace que se elimine la qdisc de entrada creada en el paso 1, liberando as\u00ed la tcx_entry previamente vinculada: rtnetlink_rcv_msg() =\u0026gt; tc_modify_qdisc() =\u0026gt; qdisc_create() =\u0026gt; clsact_init() [a] =\u0026gt; qdisc_graft() =\u0026gt; qdisc_destroy( ) =\u0026gt; __qdisc_destroy() =\u0026gt; ingress_destroy() [b] =\u0026gt; tcx_entry_free() =\u0026gt; kfree_rcu() // tcx_entry liberado 5. Finalmente, se cierra el espacio de nombres de la red. Esto registra el trabajador cleanup_net y, durante el proceso de liberaci\u00f3n de la qdisc clsact restante, accede a tcx_entry que ya se liber\u00f3 en el paso 4, lo que provoca que se produzca la UAF: cleanup_net() =\u0026gt; ops_exit_list() =\u0026gt; default_device_exit_batch() =\u0026gt; unregister_netdevice_many() =\u0026gt; unregister_netdevice_many_notify() =\u0026gt; dev_shutdown() =\u0026gt; qdisc_put() =\u0026gt; clsact_destroy() [c] =\u0026gt; tcf_block_put_ext() =\u0026gt; tcf_chain0_head_change_cb_del() =\u0026gt; tcf_chain_head_change_item() =\u0026gt; clsact_chain_head_change() =\u0026gt; mini_qdisc_pair _intercambiar( ) // UAF Tambi\u00e9n hay otras variantes, lo esencial es agregar una qdisc de ingreso (o clsact) con un bloque compartido espec\u00edfico, luego reemplazar esa qdisc, esperar a que se ejecute tcx_entry kfree_rcu() y posteriormente acceder al activo actual miniq de qdisc de una forma u otra. La soluci\u00f3n correcta es convertir el booleano miniq_active en un contador. Lo que se puede observar, en el paso 2 anterior, el contador pasa de 0-\u0026gt;1, en el paso [a] de 1-\u0026gt;2 (para que el objeto miniq permanezca activo durante el reemplazo), luego en [b] de 2-\u0026gt;1 y finalmente [c] 1-\u0026gt;0 con el eventual lanzamiento. El contador de referencia en general oscila entre [0,2] y no necesita ser at\u00f3mico ya que todo acceso al contador est\u00e1 protegido por el mutex rtnl. Con esto implementado, ya no ocurre ning\u00fan UAF y tcx_entry se libera en el momento correcto."
    }
  ],
  "id": "CVE-2024-41010",
  "lastModified": "2024-11-21T09:32:03.607",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2024-07-17T07:15:02.183",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Mailing List",
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/1cb6f0bae50441f4b4b32a28315853b279c7404e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Mailing List",
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/230bb13650b0f186f540500fd5f5f7096a822a2a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Mailing List",
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/f61ecf1bd5b562ebfd7d430ccb31619857e80857"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Mailing List",
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/1cb6f0bae50441f4b4b32a28315853b279c7404e"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Mailing List",
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/230bb13650b0f186f540500fd5f5f7096a822a2a"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Mailing List",
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/f61ecf1bd5b562ebfd7d430ccb31619857e80857"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}


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 observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.