ghsa-cjpj-m4wh-mgm6
Vulnerability from github
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.
{
"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": []
}
Sightings
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