fkie_cve-2025-38000
Vulnerability from fkie_nvd
Published
2025-06-06 13:15
Modified
2025-06-06 14:06
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: sch_hfsc: Fix qlen accounting bug when using peek in hfsc_enqueue() When enqueuing the first packet to an HFSC class, hfsc_enqueue() calls the child qdisc's peek() operation before incrementing sch->q.qlen and sch->qstats.backlog. If the child qdisc uses qdisc_peek_dequeued(), this may trigger an immediate dequeue and potential packet drop. In such cases, qdisc_tree_reduce_backlog() is called, but the HFSC qdisc's qlen and backlog have not yet been updated, leading to inconsistent queue accounting. This can leave an empty HFSC class in the active list, causing further consequences like use-after-free. This patch fixes the bug by moving the increment of sch->q.qlen and sch->qstats.backlog before the call to the child qdisc's peek() operation. This ensures that queue length and backlog are always accurate when packet drops or dequeues are triggered during the peek.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1034e3310752e8675e313f7271b348914008719a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3f3a22eebbc32b4fa8ce9c1d5f9db214b45b9335
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3f981138109f63232a5fb7165938d4c945cc1b9d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/49b21795b8e5654a7df3d910a12e1060da4c04cf
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/89c301e929a0db14ebd94b4d97764ce1d6981653
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/93c276942e75de0e5bc91576300d292e968f5a02
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f1dde3eb17dc1b8bd07aed00004b1e05fc87a3d4
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f9f593e34d2fb67644372c8f7b033bdc622ad228
Impacted products
Vendor Product Version


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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsch_hfsc: Fix qlen accounting bug when using peek in hfsc_enqueue()\n\nWhen enqueuing the first packet to an HFSC class, hfsc_enqueue() calls the\nchild qdisc\u0027s peek() operation before incrementing sch-\u003eq.qlen and\nsch-\u003eqstats.backlog. If the child qdisc uses qdisc_peek_dequeued(), this may\ntrigger an immediate dequeue and potential packet drop. In such cases,\nqdisc_tree_reduce_backlog() is called, but the HFSC qdisc\u0027s qlen and backlog\nhave not yet been updated, leading to inconsistent queue accounting. This\ncan leave an empty HFSC class in the active list, causing further\nconsequences like use-after-free.\n\nThis patch fixes the bug by moving the increment of sch-\u003eq.qlen and\nsch-\u003eqstats.backlog before the call to the child qdisc\u0027s peek() operation.\nThis ensures that queue length and backlog are always accurate when packet\ndrops or dequeues are triggered during the peek."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: sch_hfsc: Se corrige el error de contabilidad de qlen al usar peek en hfsc_enqueue(). Al encolar el primer paquete en una clase HFSC, hfsc_enqueue() llama a la operaci\u00f3n peek() de la qdisc secundaria antes de incrementar sch-\u0026gt;q.qlen y sch-\u0026gt;qstats.backlog. Si la qdisc secundaria usa qdisc_peek_dequeued(), esto puede desencadenar una desencola inmediata y una posible p\u00e9rdida de paquetes. En tales casos, se llama a qdisc_tree_reduce_backlog(), pero el qlen y el backlog de la qdisc HFSC a\u00fan no se han actualizado, lo que provoca una contabilidad de cola inconsistente. Esto puede dejar una clase HFSC vac\u00eda en la lista activa, lo que causa consecuencias adicionales como el use-after-free. Este parche corrige el error desplazando el incremento de sch-\u0026gt;q.qlen y sch-\u0026gt;qstats.backlog antes de la llamada a la operaci\u00f3n peek() de la qdisc secundaria. Esto garantiza que la longitud de la cola y el backlog sean siempre precisos cuando se activan los descartes o las desencolas de paquetes durante la inspecci\u00f3n."
    }
  ],
  "id": "CVE-2025-38000",
  "lastModified": "2025-06-06T14:06:58.193",
  "metrics": {},
  "published": "2025-06-06T13:15:39.870",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1034e3310752e8675e313f7271b348914008719a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3f3a22eebbc32b4fa8ce9c1d5f9db214b45b9335"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3f981138109f63232a5fb7165938d4c945cc1b9d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/49b21795b8e5654a7df3d910a12e1060da4c04cf"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/89c301e929a0db14ebd94b4d97764ce1d6981653"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/93c276942e75de0e5bc91576300d292e968f5a02"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f1dde3eb17dc1b8bd07aed00004b1e05fc87a3d4"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f9f593e34d2fb67644372c8f7b033bdc622ad228"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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