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GHSA-CJPJ-M4WH-MGM6

Vulnerability from github – Published: 2025-12-16 18:31 – Updated: 2025-12-16 18:31

Details

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

netconsole: Acquire su_mutex before navigating configs hierarchy

There is a race between operations that iterate over the userdata cg_children list and concurrent add/remove of userdata items through configfs. The update_userdata() function iterates over the nt->userdata_group.cg_children list, and count_extradata_entries() also iterates over this same list to count nodes.

Quoting from Documentation/filesystems/configfs.rst:

A subsystem can navigate the cg_children list and the ci_parent pointer to see the tree created by the subsystem. This can race with configfs' management of the hierarchy, so configfs uses the subsystem mutex to protect modifications. Whenever a subsystem wants to navigate the hierarchy, it must do so under the protection of the subsystem mutex.

Without proper locking, if a userdata item is added or removed concurrently while these functions are iterating, the list can be accessed in an inconsistent state. For example, the list_for_each() loop can reach a node that is being removed from the list by list_del_init() which sets the nodes' .next pointer to point to itself, so the loop will never end (or reach the WARN_ON_ONCE in update_userdata() ).

Fix this by holding the configfs subsystem mutex (su_mutex) during all operations that iterate over cg_children. This includes: - userdatum_value_store() which calls update_userdata() to iterate over cg_children - All sysdata_*_enabled_store() functions which call count_extradata_entries() to iterate over cg_children

The su_mutex must be acquired before dynamic_netconsole_mutex to avoid potential lock ordering issues, as configfs operations may already hold su_mutex when calling into our code.

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{
  "affected": [],
  "aliases": [
    "CVE-2025-68319"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-12-16T16:16:11Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetconsole: Acquire su_mutex before navigating configs hierarchy\n\nThere is a race between operations that iterate over the userdata\ncg_children list and concurrent add/remove of userdata items through\nconfigfs. The update_userdata() function iterates over the\nnt-\u003euserdata_group.cg_children list, and count_extradata_entries() also\niterates over this same list to count nodes.\n\nQuoting from Documentation/filesystems/configfs.rst:\n\u003e A subsystem can navigate the cg_children list and the ci_parent pointer\n\u003e to see the tree created by the subsystem.  This can race with configfs\u0027\n\u003e management of the hierarchy, so configfs uses the subsystem mutex to\n\u003e protect modifications.  Whenever a subsystem wants to navigate the\n\u003e hierarchy, it must do so under the protection of the subsystem\n\u003e mutex.\n\nWithout proper locking, if a userdata item is added or removed\nconcurrently while these functions are iterating, the list can be\naccessed in an inconsistent state. For example, the list_for_each() loop\ncan reach a node that is being removed from the list by list_del_init()\nwhich sets the nodes\u0027 .next pointer to point to itself, so the loop will\nnever end (or reach the WARN_ON_ONCE in update_userdata() ).\n\nFix this by holding the configfs subsystem mutex (su_mutex) during all\noperations that iterate over cg_children.\nThis includes:\n- userdatum_value_store() which calls update_userdata() to iterate over\n  cg_children\n- All sysdata_*_enabled_store() functions which call\n  count_extradata_entries() to iterate over cg_children\n\nThe su_mutex must be acquired before dynamic_netconsole_mutex to avoid\npotential lock ordering issues, as configfs operations may already hold\nsu_mutex when calling into our code.",
  "id": "GHSA-cjpj-m4wh-mgm6",
  "modified": "2025-12-16T18:31:34Z",
  "published": "2025-12-16T18:31:34Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-68319"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d7d2fcf7ae31471b4e08b7e448b8fd0ec2e06a1b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ff70aa7e8cf05745fdba7258952a8bedf33ea336"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2025-68319 (GCVE-0-2025-68319)

Vulnerability from cvelistv5 – Published: 2025-12-16 15:39 – Updated: 2026-05-11 21:50

Title

netconsole: Acquire su_mutex before navigating configs hierarchy

Summary

In the Linux kernel, the following vulnerability has been resolved: netconsole: Acquire su_mutex before navigating configs hierarchy There is a race between operations that iterate over the userdata cg_children list and concurrent add/remove of userdata items through configfs. The update_userdata() function iterates over the nt->userdata_group.cg_children list, and count_extradata_entries() also iterates over this same list to count nodes. Quoting from Documentation/filesystems/configfs.rst: > A subsystem can navigate the cg_children list and the ci_parent pointer > to see the tree created by the subsystem. This can race with configfs' > management of the hierarchy, so configfs uses the subsystem mutex to > protect modifications. Whenever a subsystem wants to navigate the > hierarchy, it must do so under the protection of the subsystem > mutex. Without proper locking, if a userdata item is added or removed concurrently while these functions are iterating, the list can be accessed in an inconsistent state. For example, the list_for_each() loop can reach a node that is being removed from the list by list_del_init() which sets the nodes' .next pointer to point to itself, so the loop will never end (or reach the WARN_ON_ONCE in update_userdata() ). Fix this by holding the configfs subsystem mutex (su_mutex) during all operations that iterate over cg_children. This includes: - userdatum_value_store() which calls update_userdata() to iterate over cg_children - All sysdata_*_enabled_store() functions which call count_extradata_entries() to iterate over cg_children The su_mutex must be acquired before dynamic_netconsole_mutex to avoid potential lock ordering issues, as configfs operations may already hold su_mutex when calling into our code.

Severity

No CVSS data available.

Assigner

Linux mitre root

References

2 references

URL	Tags
https://git.kernel.org/stable/c/ff70aa7e8cf05745f…
https://git.kernel.org/stable/c/d7d2fcf7ae31471b4…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: df03f830d099f0811281a222aefdd9d400fa0b72 , < ff70aa7e8cf05745fdba7258952a8bedf33ea336 (git) Affected: df03f830d099f0811281a222aefdd9d400fa0b72 , < d7d2fcf7ae31471b4e08b7e448b8fd0ec2e06a1b (git)
Linux	Linux	Affected: 6.9 Unaffected: 0 , < 6.9 (semver) Unaffected: 6.17.8 , ≤ 6.17.* (semver) Unaffected: 6.18 , ≤ * (original_commit_for_fix)

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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