FKIE_CVE-2025-68809

Vulnerability from fkie_nvd - Published: 2026-01-13 16:16 - Updated: 2026-04-15 00:35
Severity ?
Summary
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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5adad9727a815c26013b0d41cfee92ffa7d4037c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/991f8a79db99b14c48d20d2052c82d65b9186cad
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ccc78781041589ea383e61d5d7a1e9a31b210b93
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ee63729760f5b61a66f345c54dc4c7514e62383d
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nksmbd: vfs: corregir condici\u00f3n de carrera en m_flags en vfs_cache\n\nksmbd mantiene el estado de eliminaci\u00f3n al cerrar y eliminaci\u00f3n pendiente en ksmbd_inode-\u0026gt;m_flags. En vfs_cache.c, este campo es accedido bajo un bloqueo inconsistente: algunas rutas leen y modifican m_flags bajo ci-\u0026gt;m_lock mientras que otras lo hacen sin tomar el bloqueo en absoluto.\n\nEjemplos:\n\n - ksmbd_query_inode_status() y __ksmbd_inode_close() usan ci-\u0026gt;m_lock al verificar o actualizar m_flags.\n - ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(), ksmbd_clear_inode_pending_delete() y ksmbd_fd_set_delete_on_close() sol\u00edan leer y modificar m_flags sin ci-\u0026gt;m_lock.\n\nEsto crea una potencial condici\u00f3n de carrera de datos en m_flags cuando m\u00faltiples hilos abren, cierran y eliminan el mismo archivo concurrentemente. En el peor de los casos, los bits de eliminaci\u00f3n al cerrar y eliminaci\u00f3n pendiente pueden perderse u observarse en un estado inconsistente, lo que lleva a sem\u00e1nticas de eliminaci\u00f3n confusas (archivos que permanecen en el disco despu\u00e9s de la eliminaci\u00f3n al cerrar, o archivos que desaparecen mientras a\u00fan est\u00e1n en uso).\n\nSolucionarlo mediante:\n\n - Haciendo que ksmbd_query_inode_status() examine m_flags bajo ci-\u0026gt;m_lock despu\u00e9s de liberar inode_hash_lock.\n - A\u00f1adiendo protecci\u00f3n ci-\u0026gt;m_lock a todas las funciones auxiliares que leen o modifican m_flags (ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(), ksmbd_clear_inode_pending_delete(), ksmbd_fd_set_delete_on_close()).\n - Manteniendo la protecci\u00f3n ci-\u0026gt;m_lock existente en __ksmbd_inode_close(), y moviendo la eliminaci\u00f3n real de unlink/xattr fuera del bloqueo.\n\nEsto unifica el bloqueo alrededor de m_flags y elimina la condici\u00f3n de carrera de datos mientras se preserva el comportamiento existente de eliminaci\u00f3n al cerrar."
    }
  ],
  "id": "CVE-2025-68809",
  "lastModified": "2026-04-15T00:35:42.020",
  "metrics": {},
  "published": "2026-01-13T16:16:03.080",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5adad9727a815c26013b0d41cfee92ffa7d4037c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/991f8a79db99b14c48d20d2052c82d65b9186cad"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ccc78781041589ea383e61d5d7a1e9a31b210b93"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ee63729760f5b61a66f345c54dc4c7514e62383d"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Deferred"
}


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