fkie_cve-2025-37890
Vulnerability from fkie_nvd
Published
2025-05-16 13:15
Modified
2025-06-04 13:15
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: net_sched: hfsc: Fix a UAF vulnerability in class with netem as child qdisc As described in Gerrard's report [1], we have a UAF case when an hfsc class has a netem child qdisc. The crux of the issue is that hfsc is assuming that checking for cl->qdisc->q.qlen == 0 guarantees that it hasn't inserted the class in the vttree or eltree (which is not true for the netem duplicate case). This patch checks the n_active class variable to make sure that the code won't insert the class in the vttree or eltree twice, catering for the reentrant case. [1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/141d34391abbb315d68556b7c67ad97885407547
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/273bbcfa53541cde38b2003ad88a59b770306421
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2e7093c7a8aba5d4f8809f271488e5babe75e202
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6082a87af4c52f58150d40dec1716011d871ac21
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8df7d37d626430035b413b97cee18396b3450bef
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ac39fd4a757584d78ed062d4f6fd913f83bd98b5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e0cf8ee23e1915431f262a7b2dee0c7a7d699af0
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e3e949a39a91d1f829a4890e7dfe9417ac72e4d0
Impacted products
Vendor Product Version


To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet_sched: hfsc: Fix a UAF vulnerability in class with netem as child qdisc\n\nAs described in Gerrard\u0027s report [1], we have a UAF case when an hfsc class\nhas a netem child qdisc. The crux of the issue is that hfsc is assuming\nthat checking for cl-\u003eqdisc-\u003eq.qlen == 0 guarantees that it hasn\u0027t inserted\nthe class in the vttree or eltree (which is not true for the netem\nduplicate case).\n\nThis patch checks the n_active class variable to make sure that the code\nwon\u0027t insert the class in the vttree or eltree twice, catering for the\nreentrant case.\n\n[1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net_sched: hfsc: corrige una vulnerabilidad UAF en la clase con netem como qdisc hijo Como se describe en el informe de Gerrard [1], tenemos un caso UAF cuando una clase hfsc tiene una qdisc hijo netem. El quid de la cuesti\u00f3n es que hfsc asume que la comprobaci\u00f3n de cl-\u0026gt;qdisc-\u0026gt;q.qlen == 0 garantiza que no ha insertado la clase en vttree o eltree (lo que no es cierto para el caso de duplicado de netem). Este parche comprueba la variable de clase n_active para asegurarse de que el c\u00f3digo no inserte la clase en vttree o eltree dos veces, atendiendo al caso reentrante. [1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/"
    }
  ],
  "id": "CVE-2025-37890",
  "lastModified": "2025-06-04T13:15:26.170",
  "metrics": {},
  "published": "2025-05-16T13:15:52.437",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/141d34391abbb315d68556b7c67ad97885407547"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/273bbcfa53541cde38b2003ad88a59b770306421"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2e7093c7a8aba5d4f8809f271488e5babe75e202"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6082a87af4c52f58150d40dec1716011d871ac21"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8df7d37d626430035b413b97cee18396b3450bef"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ac39fd4a757584d78ed062d4f6fd913f83bd98b5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e0cf8ee23e1915431f262a7b2dee0c7a7d699af0"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e3e949a39a91d1f829a4890e7dfe9417ac72e4d0"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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