ghsa-wc22-wv2f-7f64
Vulnerability from github
Published
2025-09-15 15:31
Modified
2025-09-15 15:31
Details

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

NFSD: fix use-after-free on source server when doing inter-server copy

Use-after-free occurred when the laundromat tried to free expired cpntf_state entry on the s2s_cp_stateids list after inter-server copy completed. The sc_cp_list that the expired copy state was inserted on was already freed.

When COPY completes, the Linux client normally sends LOCKU(lock_state x), FREE_STATEID(lock_state x) and CLOSE(open_state y) to the source server. The nfs4_put_stid call from nfsd4_free_stateid cleans up the copy state from the s2s_cp_stateids list before freeing the lock state's stid.

However, sometimes the CLOSE was sent before the FREE_STATEID request. When this happens, the nfsd4_close_open_stateid call from nfsd4_close frees all lock states on its st_locks list without cleaning up the copy state on the sc_cp_list list. When the time the FREE_STATEID arrives the server returns BAD_STATEID since the lock state was freed. This causes the use-after-free error to occur when the laundromat tries to free the expired cpntf_state.

This patch adds a call to nfs4_free_cpntf_statelist in nfsd4_close_open_stateid to clean up the copy state before calling free_ol_stateid_reaplist to free the lock state's stid on the reaplist.

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{
  "affected": [],
  "aliases": [
    "CVE-2022-50241"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-09-15T14:15:34Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: fix use-after-free on source server when doing inter-server copy\n\nUse-after-free occurred when the laundromat tried to free expired\ncpntf_state entry on the s2s_cp_stateids list after inter-server\ncopy completed. The sc_cp_list that the expired copy state was\ninserted on was already freed.\n\nWhen COPY completes, the Linux client normally sends LOCKU(lock_state x),\nFREE_STATEID(lock_state x) and CLOSE(open_state y) to the source server.\nThe nfs4_put_stid call from nfsd4_free_stateid cleans up the copy state\nfrom the s2s_cp_stateids list before freeing the lock state\u0027s stid.\n\nHowever, sometimes the CLOSE was sent before the FREE_STATEID request.\nWhen this happens, the nfsd4_close_open_stateid call from nfsd4_close\nfrees all lock states on its st_locks list without cleaning up the copy\nstate on the sc_cp_list list. When the time the FREE_STATEID arrives the\nserver returns BAD_STATEID since the lock state was freed. This causes\nthe use-after-free error to occur when the laundromat tries to free\nthe expired cpntf_state.\n\nThis patch adds a call to nfs4_free_cpntf_statelist in\nnfsd4_close_open_stateid to clean up the copy state before calling\nfree_ol_stateid_reaplist to free the lock state\u0027s stid on the reaplist.",
  "id": "GHSA-wc22-wv2f-7f64",
  "modified": "2025-09-15T15:31:21Z",
  "published": "2025-09-15T15:31:21Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-50241"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/019805fea91599b22dfa62ffb29c022f35abeb06"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/35aa0fb8c3033a3d78603356e96fc18c5b9cceb2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6ea71246b7a02af675d733e72d14bd0d591d5f4a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/83b94969751a691347606dbe6b1865efcfa5a643"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bbacfcde5fff25ac22597e8373a065c647da6738"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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