CVE-2025-68319 (GCVE-0-2025-68319)
Vulnerability from cvelistv5
Published
2025-12-16 15:39
Modified
2025-12-16 15:39
Severity ?
VLAI Severity ?
EPSS score ?
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.
References
Impacted products
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"datePublished": "2025-12-16T15:39:48.903Z",
"dateReserved": "2025-12-16T14:48:05.295Z",
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"nvd": "{\"cve\":{\"id\":\"CVE-2025-68319\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-12-16T16:16:11.483\",\"lastModified\":\"2025-12-18T15:08:06.237\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"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.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/d7d2fcf7ae31471b4e08b7e448b8fd0ec2e06a1b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ff70aa7e8cf05745fdba7258952a8bedf33ea336\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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