ghsa-f4g2-c45m-rq74
Vulnerability from github
Published
2024-12-27 15:31
Modified
2024-12-27 15:31
Details

In the Linux kernel, the following vulnerability has been resolved:

net/l2tp: fix warning in l2tp_exit_net found by syzbot

In l2tp's net exit handler, we check that an IDR is empty before destroying it:

WARN_ON_ONCE(!idr_is_empty(&pn->l2tp_tunnel_idr));
idr_destroy(&pn->l2tp_tunnel_idr);

By forcing memory allocation failures in idr_alloc_32, syzbot is able to provoke a condition where idr_is_empty returns false despite there being no items in the IDR. This turns out to be because the radix tree of the IDR contains only internal radix-tree nodes and it is this that causes idr_is_empty to return false. The internal nodes are cleaned by idr_destroy.

Use idr_for_each to check that the IDR is empty instead of idr_is_empty to avoid the problem.

Show details on source website


{
  "affected": [],
  "aliases": [
    "CVE-2024-53211"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-12-27T14:15:29Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/l2tp: fix warning in l2tp_exit_net found by syzbot\n\nIn l2tp\u0027s net exit handler, we check that an IDR is empty before\ndestroying it:\n\n\tWARN_ON_ONCE(!idr_is_empty(\u0026pn-\u003el2tp_tunnel_idr));\n\tidr_destroy(\u0026pn-\u003el2tp_tunnel_idr);\n\nBy forcing memory allocation failures in idr_alloc_32, syzbot is able\nto provoke a condition where idr_is_empty returns false despite there\nbeing no items in the IDR. This turns out to be because the radix tree\nof the IDR contains only internal radix-tree nodes and it is this that\ncauses idr_is_empty to return false. The internal nodes are cleaned by\nidr_destroy.\n\nUse idr_for_each to check that the IDR is empty instead of\nidr_is_empty to avoid the problem.",
  "id": "GHSA-f4g2-c45m-rq74",
  "modified": "2024-12-27T15:31:52Z",
  "published": "2024-12-27T15:31:51Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-53211"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5d066766c5f1252f98ff859265bcd1a5b52ac46c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a487cc8986d6dd75b60b59004f3bd2ea9b4dd541"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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