Описание
In the Linux kernel, the following vulnerability has been resolved:
cachefiles: fix incorrect dentry refcount in cachefiles_cull()
The patch mentioned below changed cachefiles_bury_object() to expect 2
references to the 'rep' dentry. Three of the callers were changed to
use start_removing_dentry() which takes an extra reference so in those
cases the call gets the expected references.
However there is another call to cachefiles_bury_object() in
cachefiles_cull() which did not need to be changed to use
start_removing_dentry() and so was not properly considered.
It still passed the dentry with just one reference so the net result is
that a reference is lost.
To meet the expectations of cachefiles_bury_object(), cachefiles_cull()
must take an extra reference before the call. It will be dropped by
cachefiles_bury_object().
A flaw was found in the Linux kernel's cachefiles module, which manages cached files. This vulnerability stems from an error in how the system counts references to certain file system objects, specifically within the cachefiles_cull() function. When a reference is lost, it can lead to system instability. This could potentially result in a denial of service (DoS), making the system unavailable to users.
Отчет
Red Hat acknowledges the upstream Linux kernel correction for «cachefiles» as described in COMMENT_ZERO. Fixes are delivered through standard kernel errata for supported products. Operational exposure depends on whether this subsystem or driver is active in your configuration.
Меры по смягчению последствий
To mitigate this issue, prevent the cachefiles module from being loaded. See https://access.redhat.com/solutions/41278 for instructions.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Not affected | ||
| Red Hat Enterprise Linux 6 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Not affected |
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Дополнительная информация
Статус:
EPSS
5.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: cachefiles: fix incorrect dentry refcount in cachefiles_cull() The patch mentioned below changed cachefiles_bury_object() to expect 2 references to the 'rep' dentry. Three of the callers were changed to use start_removing_dentry() which takes an extra reference so in those cases the call gets the expected references. However there is another call to cachefiles_bury_object() in cachefiles_cull() which did not need to be changed to use start_removing_dentry() and so was not properly considered. It still passed the dentry with just one reference so the net result is that a reference is lost. To meet the expectations of cachefiles_bury_object(), cachefiles_cull() must take an extra reference before the call. It will be dropped by cachefiles_bury_object().
In the Linux kernel, the following vulnerability has been resolved: cachefiles: fix incorrect dentry refcount in cachefiles_cull() The patch mentioned below changed cachefiles_bury_object() to expect 2 references to the 'rep' dentry. Three of the callers were changed to use start_removing_dentry() which takes an extra reference so in those cases the call gets the expected references. However there is another call to cachefiles_bury_object() in cachefiles_cull() which did not need to be changed to use start_removing_dentry() and so was not properly considered. It still passed the dentry with just one reference so the net result is that a reference is lost. To meet the expectations of cachefiles_bury_object(), cachefiles_cull() must take an extra reference before the call. It will be dropped by cachefiles_bury_object().
In the Linux kernel, the following vulnerability has been resolved: c ...
In the Linux kernel, the following vulnerability has been resolved: cachefiles: fix incorrect dentry refcount in cachefiles_cull() The patch mentioned below changed cachefiles_bury_object() to expect 2 references to the 'rep' dentry. Three of the callers were changed to use start_removing_dentry() which takes an extra reference so in those cases the call gets the expected references. However there is another call to cachefiles_bury_object() in cachefiles_cull() which did not need to be changed to use start_removing_dentry() and so was not properly considered. It still passed the dentry with just one reference so the net result is that a reference is lost. To meet the expectations of cachefiles_bury_object(), cachefiles_cull() must take an extra reference before the call. It will be dropped by cachefiles_bury_object().
EPSS
5.5 Medium
CVSS3