Описание
In the Linux kernel, the following vulnerability has been resolved:
autofs: ignore notification errors from a replaced pipe
autofs_notify_daemon() takes a reference to the current notification
pipe under wq_mutex, then drops the mutex before writing the request. The
write can block while the daemon enters catatonic mode and installs a
replacement pipe.
If the old pipe's reader is then closed, the delayed write returns -EPIPE
and the generic error path enters catatonic mode again. That transition
acts on the current superblock state, closes the replacement pipe, and
releases the new daemon generation's wait queues.
Only enter catatonic mode when the pipe which failed is still the current
pipe. Factor the already-locked transition so the identity check and state
change are atomic with respect to another replacement.
This was reproduced on v7.3-rc5-337-gff47652a4b66c in a local QEMU guest.
An unprivileged UID 65534 lookup filled the old packet pipe before a
normal CATATONIC/SETPIPEFD restart. On the unmodified kernel, the new pipe
received HUP and both a pending victim lookup and a later lookup failed
with ENOENT in two out of two fresh-mount runs.
With this change, the new pipe remained active, received an intact
304-byte request, and both victim lookups completed in two out of two
runs. Normal lookup and restart-without-a-blocked-writer controls passed.
No KASAN, oops, refcount, or lock diagnostic was observed. A source
reproducer and complete local logs are available privately on request.
The demonstrated impact is limited to denial of a shared autofs service
during a legitimate daemon restart. No memory corruption, information leak,
privilege escalation, or code execution primitive was observed.
A flaw was found in the Linux kernel's autofs (automount file system) subsystem. A local attacker can cause a Denial of Service (DoS) by initiating file system lookups while the automount daemon is restarting. Due to mishandled errors from an obsolete communication pipe, the kernel incorrectly shuts down the newly replaced pipe, causing subsequent autofs lookups and mount requests to fail.
Отчет
This vulnerability is rated as having Moderate severity for Red Hat enterprise environments because exploitation requires unprivileged local access and precise timing during an automounter restart, resulting strictly in the disruption of autofs requests without memory corruption or privilege escalation. Although the underlying autofs subsystem is present across Red Hat Enterprise Linux installations, active risk is limited to systems where automount services are deployed to handle dynamic mounts such as network file shares. Systems where automount daemons are inactive or not exposed to untrusted local users are not susceptible to this denial of service.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Fix deferred | ||
| 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 | Fix deferred | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Fix deferred | ||
| Red Hat Enterprise Linux 9 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Fix deferred | ||
| 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:
4.7 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: autofs: ignore notification errors from a replaced pipe autofs_notify_daemon() takes a reference to the current notification pipe under wq_mutex, then drops the mutex before writing the request. The write can block while the daemon enters catatonic mode and installs a replacement pipe. If the old pipe's reader is then closed, the delayed write returns -EPIPE and the generic error path enters catatonic mode again. That transition acts on the current superblock state, closes the replacement pipe, and releases the new daemon generation's wait queues. Only enter catatonic mode when the pipe which failed is still the current pipe. Factor the already-locked transition so the identity check and state change are atomic with respect to another replacement. This was reproduced on v7.3-rc5-337-gff47652a4b66c in a local QEMU guest. An unprivileged UID 65534 lookup filled the old packet pipe before a normal CATATONIC/SETPIPEFD r...
In the Linux kernel, the following vulnerability has been resolved: autofs: ignore notification errors from a replaced pipe autofs_notify_daemon() takes a reference to the current notification pipe under wq_mutex, then drops the mutex before writing the request. The write can block while the daemon enters catatonic mode and installs a replacement pipe. If the old pipe's reader is then closed, the delayed write returns -EPIPE and the generic error path enters catatonic mode again. That transition acts on the current superblock state, closes the replacement pipe, and releases the new daemon generation's wait queues. Only enter catatonic mode when the pipe which failed is still the current pipe. Factor the already-locked transition so the identity check and state change are atomic with respect to another replacement. This was reproduced on v7.3-rc5-337-gff47652a4b66c in a local QEMU guest. An unprivileged UID 65534 lookup filled the old packet pipe before a normal CATATONIC/SETPIPEFD
In the Linux kernel, the following vulnerability has been resolved: a ...
In the Linux kernel, the following vulnerability has been resolved: autofs: ignore notification errors from a replaced pipe autofs_notify_daemon() takes a reference to the current notification pipe under wq_mutex, then drops the mutex before writing the request. The write can block while the daemon enters catatonic mode and installs a replacement pipe. If the old pipe's reader is then closed, the delayed write returns -EPIPE and the generic error path enters catatonic mode again. That transition acts on the current superblock state, closes the replacement pipe, and releases the new daemon generation's wait queues. Only enter catatonic mode when the pipe which failed is still the current pipe. Factor the already-locked transition so the identity check and state change are atomic with respect to another replacement. This was reproduced on v7.3-rc5-337-gff47652a4b66c in a local QEMU guest. An unprivileged UID 65534 lookup filled the old packet pipe before a normal CATATONIC/SETPIP...
4.7 Medium
CVSS3