Описание
In the Linux kernel, the following vulnerability has been resolved:
ovpn: fix peer refcount leak in TCP error paths
When either the TCP RX or TX error path calls ovpn_peer_hold() followed
by schedule_work(&peer->tcp.defer_del_work), and the work item is already
pending from the other path, schedule_work() returns false and the work
runs only once. Since ovpn_tcp_peer_del_work() calls ovpn_peer_put()
exactly once, the extra reference taken by the losing path is never
dropped, leaking the peer object.
The race window:
CPU0 (strparser/RX error): CPU1 (tcp_tx_work/TX error):
ovpn_peer_hold() <- refcnt+1 ovpn_peer_hold() <- refcnt+2
schedule_work() <- queued schedule_work() <- NO-OP
(work already pending)
ovpn_tcp_peer_del_work runs:
ovpn_peer_del()
ovpn_peer_put() <- refcnt+1
<- peer never freed
Fix by checking the return value of schedule_work() in both paths and
calling ovpn_peer_put() to drop the extra reference if the work was
already pending. ovpn_peer_hold() is kept unconditional in the TX path
as it cannot fail at that point.
A flaw was found in the Linux kernel's ovpn module. A race condition in the TCP error handling paths can lead to a reference count leak. This occurs when an internal object's reference count is incremented twice but decremented only once, preventing the object from being properly released. Over time, this resource exhaustion could lead to a Denial of Service (DoS) condition.
Отчет
This issue affects OpenVPN kernel (ovpn) TCP mode. Concurrent RX/TX error paths can schedule defer_del_work only once while holding two peer references, leaking refcounts. Systems not using ovpn are not affected.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Not affected | ||
| Red Hat Enterprise Linux 6 | kernel | Not affected | ||
| 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 | ||
| Red Hat Enterprise Linux for NVIDIA 26 | kernel | Not affected | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-8 | Not affected |
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Дополнительная информация
Статус:
5.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: ovpn: fix peer refcount leak in TCP error paths When either the TCP RX or TX error path calls ovpn_peer_hold() followed by schedule_work(&peer->tcp.defer_del_work), and the work item is already pending from the other path, schedule_work() returns false and the work runs only once. Since ovpn_tcp_peer_del_work() calls ovpn_peer_put() exactly once, the extra reference taken by the losing path is never dropped, leaking the peer object. The race window: CPU0 (strparser/RX error): CPU1 (tcp_tx_work/TX error): ovpn_peer_hold() <- refcnt+1 ovpn_peer_hold() <- refcnt+2 schedule_work() <- queued schedule_work() <- NO-OP (work already pending) ovpn_tcp_peer_del_work runs: ovpn_peer_del() ovpn_peer_put() <- refcnt+1 <- peer never freed Fix by checking the return value of schedule_work() in both paths and calling ovpn_peer_put() to drop the extra reference if the work was already pending. ovpn_peer_hold(...
In the Linux kernel, the following vulnerability has been resolved: ovpn: fix peer refcount leak in TCP error paths When either the TCP RX or TX error path calls ovpn_peer_hold() followed by schedule_work(&peer->tcp.defer_del_work), and the work item is already pending from the other path, schedule_work() returns false and the work runs only once. Since ovpn_tcp_peer_del_work() calls ovpn_peer_put() exactly once, the extra reference taken by the losing path is never dropped, leaking the peer object. The race window: CPU0 (strparser/RX error): CPU1 (tcp_tx_work/TX error): ovpn_peer_hold() <- refcnt+1 ovpn_peer_hold() <- refcnt+2 schedule_work() <- queued schedule_work() <- NO-OP (work already pending) ovpn_tcp_peer_del_work runs: ovpn_peer_del() ovpn_peer_put() <- refcnt+1 <- peer never freed Fix by checking the return value of schedule_work() in both paths and calling ovp
In the Linux kernel, the following vulnerability has been resolved: o ...
In the Linux kernel, the following vulnerability has been resolved: ovpn: fix peer refcount leak in TCP error paths When either the TCP RX or TX error path calls ovpn_peer_hold() followed by schedule_work(&peer->tcp.defer_del_work), and the work item is already pending from the other path, schedule_work() returns false and the work runs only once. Since ovpn_tcp_peer_del_work() calls ovpn_peer_put() exactly once, the extra reference taken by the losing path is never dropped, leaking the peer object. The race window: CPU0 (strparser/RX error): CPU1 (tcp_tx_work/TX error): ovpn_peer_hold() <- refcnt+1 ovpn_peer_hold() <- refcnt+2 schedule_work() <- queued schedule_work() <- NO-OP (work already pending) ovpn_tcp_peer_del_work runs: ovpn_peer_del() ovpn_peer_put() <- refcnt+1 <- peer never freed Fix by checking the return value of schedule_work() in both paths and calling ...
5.5 Medium
CVSS3