Описание
In the Linux kernel, the following vulnerability has been resolved:
lockd: pin next file across nlm_inspect_file lock-drop
nlm_traverse_files() pins the current file with f_count++ across
a mutex_unlock for nlm_inspect_file(), but nothing pins the saved
next pointer. A concurrent nlm_release_file() can kfree the next
file during the unlock window, and the iterator dereferences freed
memory on the next loop step.
Pin both current and next before the lock-drop. Advance by
swapping the pinned cursors at the end of each iteration so next
is always held alive across the unlock.
Always call nlm_file_release() after dropping the iteration pin,
regardless of whether the file matched the predicate. Use
nlm_file_inuse(), which does a live walk of the inode lock list,
rather than the cached f_locks field, so skipped files that never
ran nlm_inspect_file() are evaluated correctly.
Because every file in a hash bucket is now pinned and released,
files skipped by the is_failover_file predicate that have no
locks, blocks, shares, or external references are deleted during
traversal. The old code never evaluated skipped files for
cleanup. The new behavior is intentional: such files are stale
and should not persist in the table.
A flaw was found in the lockd component of the Linux kernel. This use-after-free vulnerability occurs in the nlm_traverse_files() function when a file's memory is prematurely released while an iterator still holds a pointer to it. A remote attacker could potentially exploit this to cause system instability or a denial of service (DoS) by triggering a concurrent file release during a specific unlock window.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-8 | Fix deferred | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-9 | Fix deferred |
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Дополнительная информация
Статус:
EPSS
5.3 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: lockd: pin next file across nlm_inspect_file lock-drop nlm_traverse_files() pins the current file with f_count++ across a mutex_unlock for nlm_inspect_file(), but nothing pins the saved next pointer. A concurrent nlm_release_file() can kfree the next file during the unlock window, and the iterator dereferences freed memory on the next loop step. Pin both current and next before the lock-drop. Advance by swapping the pinned cursors at the end of each iteration so next is always held alive across the unlock. Always call nlm_file_release() after dropping the iteration pin, regardless of whether the file matched the predicate. Use nlm_file_inuse(), which does a live walk of the inode lock list, rather than the cached f_locks field, so skipped files that never ran nlm_inspect_file() are evaluated correctly. Because every file in a hash bucket is now pinned and released, files skipped by the is_failover_file predicate ...
In the Linux kernel, the following vulnerability has been resolved: lockd: pin next file across nlm_inspect_file lock-drop nlm_traverse_files() pins the current file with f_count++ across a mutex_unlock for nlm_inspect_file(), but nothing pins the saved next pointer. A concurrent nlm_release_file() can kfree the next file during the unlock window, and the iterator dereferences freed memory on the next loop step. Pin both current and next before the lock-drop. Advance by swapping the pinned cursors at the end of each iteration so next is always held alive across the unlock. Always call nlm_file_release() after dropping the iteration pin, regardless of whether the file matched the predicate. Use nlm_file_inuse(), which does a live walk of the inode lock list, rather than the cached f_locks field, so skipped files that never ran nlm_inspect_file() are evaluated correctly. Because every file in a hash bucket is now pinned and released, files skipped by the is_failover_file predicat
In the Linux kernel, the following vulnerability has been resolved: l ...
In the Linux kernel, the following vulnerability has been resolved: lockd: pin next file across nlm_inspect_file lock-drop nlm_traverse_files() pins the current file with f_count++ across a mutex_unlock for nlm_inspect_file(), but nothing pins the saved next pointer. A concurrent nlm_release_file() can kfree the next file during the unlock window, and the iterator dereferences freed memory on the next loop step. Pin both current and next before the lock-drop. Advance by swapping the pinned cursors at the end of each iteration so next is always held alive across the unlock. Always call nlm_file_release() after dropping the iteration pin, regardless of whether the file matched the predicate. Use nlm_file_inuse(), which does a live walk of the inode lock list, rather than the cached f_locks field, so skipped files that never ran nlm_inspect_file() are evaluated correctly. Because every file in a hash bucket is now pinned and released, files skipped by the is_failover_file predi...
EPSS
5.3 Medium
CVSS3