GHSA-FFPF-RF35-3FHQ

Vulnerability from github – Published: 2026-01-13 18:31 – Updated: 2026-01-13 18:31
VLAI?
Details

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

ksmbd: vfs: fix race on m_flags in vfs_cache

ksmbd maintains delete-on-close and pending-delete state in ksmbd_inode->m_flags. In vfs_cache.c this field is accessed under inconsistent locking: some paths read and modify m_flags under ci->m_lock while others do so without taking the lock at all.

Examples:

  • ksmbd_query_inode_status() and __ksmbd_inode_close() use ci->m_lock when checking or updating m_flags.
  • ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(), ksmbd_clear_inode_pending_delete() and ksmbd_fd_set_delete_on_close() used to read and modify m_flags without ci->m_lock.

This creates a potential data race on m_flags when multiple threads open, close and delete the same file concurrently. In the worst case delete-on-close and pending-delete bits can be lost or observed in an inconsistent state, leading to confusing delete semantics (files that stay on disk after delete-on-close, or files that disappear while still in use).

Fix it by:

  • Making ksmbd_query_inode_status() look at m_flags under ci->m_lock after dropping inode_hash_lock.
  • Adding ci->m_lock protection to all helpers that read or modify m_flags (ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(), ksmbd_clear_inode_pending_delete(), ksmbd_fd_set_delete_on_close()).
  • Keeping the existing ci->m_lock protection in __ksmbd_inode_close(), and moving the actual unlink/xattr removal outside the lock.

This unifies the locking around m_flags and removes the data race while preserving the existing delete-on-close behaviour.

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{
  "affected": [],
  "aliases": [
    "CVE-2025-68809"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-01-13T16:16:03Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: vfs: fix race on m_flags in vfs_cache\n\nksmbd maintains delete-on-close and pending-delete state in\nksmbd_inode-\u003em_flags. In vfs_cache.c this field is accessed under\ninconsistent locking: some paths read and modify m_flags under\nci-\u003em_lock while others do so without taking the lock at all.\n\nExamples:\n\n - ksmbd_query_inode_status() and __ksmbd_inode_close() use\n   ci-\u003em_lock when checking or updating m_flags.\n - ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(),\n   ksmbd_clear_inode_pending_delete() and ksmbd_fd_set_delete_on_close()\n   used to read and modify m_flags without ci-\u003em_lock.\n\nThis creates a potential data race on m_flags when multiple threads\nopen, close and delete the same file concurrently. In the worst case\ndelete-on-close and pending-delete bits can be lost or observed in an\ninconsistent state, leading to confusing delete semantics (files that\nstay on disk after delete-on-close, or files that disappear while still\nin use).\n\nFix it by:\n\n - Making ksmbd_query_inode_status() look at m_flags under ci-\u003em_lock\n   after dropping inode_hash_lock.\n - Adding ci-\u003em_lock protection to all helpers that read or modify\n   m_flags (ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(),\n   ksmbd_clear_inode_pending_delete(), ksmbd_fd_set_delete_on_close()).\n - Keeping the existing ci-\u003em_lock protection in __ksmbd_inode_close(),\n   and moving the actual unlink/xattr removal outside the lock.\n\nThis unifies the locking around m_flags and removes the data race while\npreserving the existing delete-on-close behaviour.",
  "id": "GHSA-ffpf-rf35-3fhq",
  "modified": "2026-01-13T18:31:04Z",
  "published": "2026-01-13T18:31:04Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-68809"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5adad9727a815c26013b0d41cfee92ffa7d4037c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/991f8a79db99b14c48d20d2052c82d65b9186cad"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ccc78781041589ea383e61d5d7a1e9a31b210b93"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ee63729760f5b61a66f345c54dc4c7514e62383d"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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