GHSA-Q53P-QM4C-C2WJ

Vulnerability from github – Published: 2024-09-11 18:31 – Updated: 2025-11-04 00:31
VLAI?
Details

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

netem: fix return value if duplicate enqueue fails

There is a bug in netem_enqueue() introduced by commit 5845f706388a ("net: netem: fix skb length BUG_ON in __skb_to_sgvec") that can lead to a use-after-free.

This commit made netem_enqueue() always return NET_XMIT_SUCCESS when a packet is duplicated, which can cause the parent qdisc's q.qlen to be mistakenly incremented. When this happens qlen_notify() may be skipped on the parent during destruction, leaving a dangling pointer for some classful qdiscs like DRR.

There are two ways for the bug happen:

  • If the duplicated packet is dropped by rootq->enqueue() and then the original packet is also dropped.
  • If rootq->enqueue() sends the duplicated packet to a different qdisc and the original packet is dropped.

In both cases NET_XMIT_SUCCESS is returned even though no packets are enqueued at the netem qdisc.

The fix is to defer the enqueue of the duplicate packet until after the original packet has been guaranteed to return NET_XMIT_SUCCESS.

Severity ?
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2024-45016"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-09-11T16:15:06Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetem: fix return value if duplicate enqueue fails\n\nThere is a bug in netem_enqueue() introduced by\ncommit 5845f706388a (\"net: netem: fix skb length BUG_ON in __skb_to_sgvec\")\nthat can lead to a use-after-free.\n\nThis commit made netem_enqueue() always return NET_XMIT_SUCCESS\nwhen a packet is duplicated, which can cause the parent qdisc\u0027s q.qlen\nto be mistakenly incremented. When this happens qlen_notify() may be\nskipped on the parent during destruction, leaving a dangling pointer\nfor some classful qdiscs like DRR.\n\nThere are two ways for the bug happen:\n\n- If the duplicated packet is dropped by rootq-\u003eenqueue() and then\n  the original packet is also dropped.\n- If rootq-\u003eenqueue() sends the duplicated packet to a different qdisc\n  and the original packet is dropped.\n\nIn both cases NET_XMIT_SUCCESS is returned even though no packets\nare enqueued at the netem qdisc.\n\nThe fix is to defer the enqueue of the duplicate packet until after\nthe original packet has been guaranteed to return NET_XMIT_SUCCESS.",
  "id": "GHSA-q53p-qm4c-c2wj",
  "modified": "2025-11-04T00:31:23Z",
  "published": "2024-09-11T18:31:05Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-45016"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0486d31dd8198e22b63a4730244b38fffce6d469"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/52d99a69f3d556c6426048c9d481b912205919d8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/577d6c0619467fe90f7e8e57e45cb5bd9d936014"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/759e3e8c4a6a6b4e52ebc4547123a457f0ce90d4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c07ff8592d57ed258afee5a5e04991a48dbaf382"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c414000da1c2ea1ba9a5e5bb1a4ba774e51e202d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e5bb2988a310667abed66c7d3ffa28880cf0f883"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2024/10/msg00003.html"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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