{
  "id": "CVE-2024-35839",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2024-05-17T15:15:21.017",
  "lastModified": "2024-11-21T09:21:01.073",
  "vulnStatus": "Awaiting Analysis",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: bridge: replace physindev with physinif in nf_bridge_info\n\nAn skb can be added to a neigh->arp_queue while waiting for an arp\nreply. Where original skb's skb->dev can be different to neigh's\nneigh->dev. For instance in case of bridging dnated skb from one veth to\nanother, the skb would be added to a neigh->arp_queue of the bridge.\n\nAs skb->dev can be reset back to nf_bridge->physindev and used, and as\nthere is no explicit mechanism that prevents this physindev from been\nfreed under us (for instance neigh_flush_dev doesn't cleanup skbs from\ndifferent device's neigh queue) we can crash on e.g. this stack:\n\narp_process\n  neigh_update\n    skb = __skb_dequeue(&neigh->arp_queue)\n      neigh_resolve_output(..., skb)\n        ...\n          br_nf_dev_xmit\n            br_nf_pre_routing_finish_bridge_slow\n              skb->dev = nf_bridge->physindev\n              br_handle_frame_finish\n\nLet's use plain ifindex instead of net_device link. To peek into the\noriginal net_device we will use dev_get_by_index_rcu(). Thus either we\nget device and are safe to use it or we don't get it and drop skb."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: netfilter: bridge: reemplace physindev con physinif en nf_bridge_info. Se puede agregar un skb a neigh->arp_queue mientras se espera una respuesta de arp. Donde skb->dev del skb original puede ser diferente al neigh->dev de neigh. Por ejemplo, en el caso de unir un skb designado de un veth a otro, el skb se agregar\u00eda a un vecino->arp_queue del puente. Como skb->dev se puede restablecer a nf_bridge->physindev y usarse, y como no existe un mecanismo expl\u00edcito que impida que este physindev se libere bajo nuestra responsabilidad (por ejemplo, neigh_flush_dev no limpia skbs de la cola vecina de diferentes dispositivos), podemos crashear, por ejemplo, en esta pila: arp_process neigh_update skb = __skb_dequeue(&neigh->arp_queue) neigh_resolve_output(..., skb) ... br_nf_dev_xmit br_nf_pre_routing_finish_bridge_slow skb->dev = nf_bridge->physindev br_handle_frame_finish Usemos ifindex simple en lugar de enlace net_device. Para echar un vistazo al net_device original usaremos dev_get_by_index_rcu(). Por lo tanto, o obtenemos el dispositivo y podemos usarlo con seguridad o no lo obtenemos y eliminamos skb."
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/544add1f1cfb78c3dfa3e6edcf4668f6be5e730c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7ae19ee81ca56b13c50a78de6c47d5b8fdc9d97b",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/9325e3188a9cf3f69fc6f32af59844bbc5b90547",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/9874808878d9eed407e3977fd11fee49de1e1d86",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/544add1f1cfb78c3dfa3e6edcf4668f6be5e730c",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://git.kernel.org/stable/c/7ae19ee81ca56b13c50a78de6c47d5b8fdc9d97b",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://git.kernel.org/stable/c/9325e3188a9cf3f69fc6f32af59844bbc5b90547",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://git.kernel.org/stable/c/9874808878d9eed407e3977fd11fee49de1e1d86",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ]
}