nfsd: fix race between laundromat and free_stateid

{
  "id": "120342194b40c5ba43707f50c21303e44cc0f95465509d2c171451ebfcffec86",
  "url": "https://osv.dev/vulnerability/CVE-2024-50106",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "nfsd: fix race between laundromat and free_stateid",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: nfsd: fix race between laundromat and free_stateid There is a race between laundromat handling of revoked delegations and a client sending free_stateid operation. Laundromat thread finds that delegation has expired and needs to be revoked so it marks the delegation stid revoked and it puts it on a reaper list but then it unlock the state lock and the actual delegation revocation happens without the lock. Once the stid is marked revoked a racing free_stateid processing thread does the following (1) it calls list_del_init() which removes it from the reaper list and (2) frees the delegation stid structure. The laundromat thread ends up not calling the revoke_delegation() function for this particular delegation but that means it will no release the lock lease that exists on the file. Now, a new open for this file comes in and ends up finding that lease list isn't empty and calls nfsd_breaker_owns_lease() which ends up trying to derefence a freed delegation stateid. Leading to the followint use-after-free KASAN warning: kernel: ================================================================== kernel: BUG: KASAN: slab-use-after-free in nfsd_breaker_owns_lease+0x140/0x160 [nfsd] kernel: Read of size 8 at addr ffff0000e73cd0c8 by task nfsd/6205 kernel: kernel: CPU: 2 UID: 0 PID: 6205 Comm: nfsd Kdump: loaded Not tainted 6.11.0-rc7+ #9 kernel: Hardware name: Apple Inc. Apple Virtualization Generic Platform, BIOS 2069",
    "evidence": "osv:CVE-2024-50106",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.11.6",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "critical",
    "structured": {
      "id": "CVE-2024-50106",
      "aliases": [
        "CVE-2024-50106"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "83e733161fde43e2f99cefa68e369944460fce39"
                },
                {
                  "fixed": "967faa26f313a62e7bebc55d5b8122eaee43b929"
                },
                {
                  "fixed": "8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-50106.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.9.0"
                },
                {
                  "fixed": "6.11.6"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-50106.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:26.764353519Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a",
        "https://git.kernel.org/stable/c/967faa26f313a62e7bebc55d5b8122eaee43b929",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/50xxx/CVE-2024-50106.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2024-50106",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/50xxx/CVE-2024-50106.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2024-50106",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 493190,
  "published_at": "2024-11-05T17:10:40.747+00:00"
}