Описание
In the Linux kernel, the following vulnerability has been resolved:
ipv6: flowlabel: cap duplicate leases per socket
ipv6_flowlabel_get() allocates an ipv6_fl_socklist entry for every
successful GET. The recheck path for a compatible existing flowlabel
links another lease without applying any lease admission check. Repeated
GET requests for one shareable label can therefore grow a socket's lease
list without bound.
Reject a new unprivileged lease once the socket already holds
FL_MAX_PER_SOCK leases. Check this on the shared recheck path so reuse
of a globally interned label, including the fl_intern() collision path,
is covered as well. New-label admission remains under the existing
mem_check() policy.
Use capable(CAP_NET_ADMIN) rather than ns_capable(), matching
mem_check(). An unprivileged user must not bypass the cap by creating a
user namespace and a netns where they have CAP_NET_ADMIN, which would
still consume host memory.
Check the capability only when the socket reaches the limit, so
successful unprivileged GET requests below the cap do not generate a
capability audit. Do the admission check before updating linger and
expires so a rejected GET does not refresh the shared label, matching
the existing socket-list allocation failure path.
A flaw was found in the Linux kernel's IPv6 (Internet Protocol version 6) subsystem. A local unprivileged user can cause a Denial of Service (DoS) by repeatedly requesting leases for a shared network flow label. Because the kernel fails to enforce per-socket lease limits during label reuse, memory is allocated without restriction, potentially exhausting system resources and causing the host to crash.
Отчет
A low impact denial of service flaw was found in the Linux kernel's IPv6 flow label handling, affecting Red Hat Enterprise Linux (kernel and kernel-rt), Red Hat In-Vehicle OS, and the OpenShift Container Platform RHEL CoreOS kernel. The ipv6_flowlabel_get() function allocates an ipv6_fl_socklist lease entry for every successful flow label request, and the recheck path for an existing shareable flow label does not apply a per-socket lease admission check. A local unprivileged attacker could exploit this by repeatedly requesting leases for the same shareable IPv6 flow label, growing the socket's lease list and kernel memory consumption without bound, potentially causing memory exhaustion and crashing the host. Confidentiality and integrity are not affected. Red Hat Product Security rates the impact of this issue as Low because exploitation requires local access with authenticated user privileges and only system availability is impacted; this differs from the upstream CVSS:3.1 base score of 5.5 (Moderate), which reflects the availability-only impact of local memory exhaustion. Fixes for the affected streams are currently deferred, so the residual risk of a local denial of service remains until a fix is delivered; the Red Hat Enterprise Linux 6 stream is out of support scope and will not receive a fix.
Меры по смягчению последствий
Mitigation for this issue is either not available or the currently available options do not 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 | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Fix deferred | ||
| 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:
EPSS
5.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: ipv6: flowlabel: cap duplicate leases per socket ipv6_flowlabel_get() allocates an ipv6_fl_socklist entry for every successful GET. The recheck path for a compatible existing flowlabel links another lease without applying any lease admission check. Repeated GET requests for one shareable label can therefore grow a socket's lease list without bound. Reject a new unprivileged lease once the socket already holds FL_MAX_PER_SOCK leases. Check this on the shared recheck path so reuse of a globally interned label, including the fl_intern() collision path, is covered as well. New-label admission remains under the existing mem_check() policy. Use capable(CAP_NET_ADMIN) rather than ns_capable(), matching mem_check(). An unprivileged user must not bypass the cap by creating a user namespace and a netns where they have CAP_NET_ADMIN, which would still consume host memory. Check the capability only when the socket reaches the l...
In the Linux kernel, the following vulnerability has been resolved: ipv6: flowlabel: cap duplicate leases per socket ipv6_flowlabel_get() allocates an ipv6_fl_socklist entry for every successful GET. The recheck path for a compatible existing flowlabel links another lease without applying any lease admission check. Repeated GET requests for one shareable label can therefore grow a socket's lease list without bound. Reject a new unprivileged lease once the socket already holds FL_MAX_PER_SOCK leases. Check this on the shared recheck path so reuse of a globally interned label, including the fl_intern() collision path, is covered as well. New-label admission remains under the existing mem_check() policy. Use capable(CAP_NET_ADMIN) rather than ns_capable(), matching mem_check(). An unprivileged user must not bypass the cap by creating a user namespace and a netns where they have CAP_NET_ADMIN, which would still consume host memory. Check the capability only when the socket reaches the
In the Linux kernel, the following vulnerability has been resolved: i ...
In the Linux kernel, the following vulnerability has been resolved: ipv6: flowlabel: cap duplicate leases per socket ipv6_flowlabel_get() allocates an ipv6_fl_socklist entry for every successful GET. The recheck path for a compatible existing flowlabel links another lease without applying any lease admission check. Repeated GET requests for one shareable label can therefore grow a socket's lease list without bound. Reject a new unprivileged lease once the socket already holds FL_MAX_PER_SOCK leases. Check this on the shared recheck path so reuse of a globally interned label, including the fl_intern() collision path, is covered as well. New-label admission remains under the existing mem_check() policy. Use capable(CAP_NET_ADMIN) rather than ns_capable(), matching mem_check(). An unprivileged user must not bypass the cap by creating a user namespace and a netns where they have CAP_NET_ADMIN, which would still consume host memory. Check the capability only when the socket reaches ...
EPSS
5.5 Medium
CVSS3