Описание
In the Linux kernel, the following vulnerability has been resolved:
io_uring/net: don't overconsume buffers when using MSG_TRUNC
When a recv/recvmsg is issued with MSG_TRUNC and the incoming packet is
larger than the provided buffer, the net layer returns the full length
of the packet rather than the number of bytes actually copied into the
buffer. As a result, io_uring advances more of the provided buffer ring
than was actually filled. Use the actual filled region size to consume
the buffer, but still return the full size to preserve MSG_TRUNC
semantics.
Take care with multishot, because that seems to already truncate the
consumption based on the available payload size.
This was reported in https://github.com/axboe/liburing/issues/1619.
[axboe: fold in size_t unsigned fix]
A flaw was found in the Linux kernel's io_uring subsystem. This vulnerability allows a local user to cause a denial of service (DoS) or buffer corruption. When handling network receive operations configured with the packet truncation flag (MSG_TRUNC), the kernel calculates buffer consumption based on the total packet length instead of the bytes actually copied into the buffer. This mismatch causes io_uring to advance the buffer ring past the filled region, resulting in overconsumption of buffers and potential system instability.
Отчет
An io_uring receive operation using MSG_TRUNC can incorrectly consume the full reported packet length from a provided buffer ring even when only part of the packet was copied. This can advance the ring beyond the buffers that were actually filled, prematurely consume available entries, and cause ENOBUFS, dropped messages, or disruption of the receiving application. A remote peer may trigger the condition by sending packets larger than the selected buffers when a network service uses io_uring provided buffer rings, incremental buffer consumption, and MSG_TRUNC. For the CVSS the PR:N value is used because an attacker only needs network access to an already configured vulnerable service and does not need a local account on the target. The required io_uring configuration and application behavior make the attack conditional and support AC:H. Impact is primarily limited denial of service. The paranoid score includes limited integrity impact because incorrect buffer accounting may cause message loss or application level data misassociation, but there is no demonstrated UAF, OOB access, arbitrary write, kernel crash, or privilege escalation primitive.
Меры по смягчению последствий
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Fix deferred | ||
| 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 | Fix deferred | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Not affected | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-8 | Not affected | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-9 | Fix deferred |
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Дополнительная информация
Статус:
2.9 Low
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: io_uring/net: don't overconsume buffers when using MSG_TRUNC When a recv/recvmsg is issued with MSG_TRUNC and the incoming packet is larger than the provided buffer, the net layer returns the full length of the packet rather than the number of bytes actually copied into the buffer. As a result, io_uring advances more of the provided buffer ring than was actually filled. Use the actual filled region size to consume the buffer, but still return the full size to preserve MSG_TRUNC semantics. Take care with multishot, because that seems to already truncate the consumption based on the available payload size. This was reported in https://github.com/axboe/liburing/issues/1619. [axboe: fold in size_t unsigned fix]
Rejected reason: This CVE ID has been rejected or withdrawn by its CVE Numbering Authority.
In the Linux kernel, the following vulnerability has been resolved: io_uring/net: don't overconsume buffers when using MSG_TRUNC When a recv/recvmsg is issued with MSG_TRUNC and the incoming packet is larger than the provided buffer, the net layer returns the full length of the packet rather than the number of bytes actually copied into the buffer. As a result, io_uring advances more of the provided buffer ring than was actually filled. Use the actual filled region size to consume the buffer, but still return the full size to preserve MSG_TRUNC semantics. Take care with multishot, because that seems to already truncate the consumption based on the available payload size. This was reported in https://github.com/axboe/liburing/issues/1619. [axboe: fold in size_t unsigned fix]
ELSA-2026-500572: Unbreakable Enterprise kernel security update (IMPORTANT)
2.9 Low
CVSS3