Описание
In the Linux kernel, the following vulnerability has been resolved:
net: microchip: vcap: fix races on the shared Super VCAP block
The VCAP instances on a chip are not independent, yet they are locked
independently. On sparx5 and lan969x the IS0 and IS2 instances are
backed by the same Super VCAP hardware block and share its cache and
command registers: every access drives the shared VCAP_SUPER_CTRL
register and moves data through the shared cache registers.
Accessing one instance therefore races with accessing another. The
per-instance admin->lock cannot prevent this, as each instance takes a
different lock.
The locking issue is mostly disguised by the fact that the core usage of
the vcap api runs under rtnl. However, the full rule dump in debugfs
decodes rules straight from hardware (a READ command followed by a cache
read) and runs outside rtnl, so it races a concurrent tc-flower rule
write to another Super VCAP instance.
Besides corrupting the dump, the read repopulates the shared cache
between the writers cache fill and its write command, so the writer
commits the wrong data and corrupts the hardware entry.
Introduce vcap_lock() and vcap_unlock() helpers and route every rule
lock site in the VCAP API and its debugfs code through them. Replace the
per-instance admin->lock with a single mutex in struct vcap_control that
serializes access to all instances. The helpers reach it through a new
admin->vctrl back-pointer, and the clients initialise and destroy the
control lock instead of a per-instance one.
No path holds more than one instance lock, so collapsing them onto a
single mutex cannot self-deadlock.
A flaw was found in the Linux kernel's Microchip VCAP driver. A race condition exists in the shared Super VCAP block, where independent locking of VCAP instances can lead to concurrent access issues. A local attacker with the ability to trigger concurrent operations, such as a full rule dump in debugfs while another instance is being written to, could exploit this. This can result in the corruption of hardware entries and incorrect data being committed.
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 |
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Дополнительная информация
Статус:
EPSS
5.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: net: microchip: vcap: fix races on the shared Super VCAP block The VCAP instances on a chip are not independent, yet they are locked independently. On sparx5 and lan969x the IS0 and IS2 instances are backed by the same Super VCAP hardware block and share its cache and command registers: every access drives the shared VCAP_SUPER_CTRL register and moves data through the shared cache registers. Accessing one instance therefore races with accessing another. The per-instance admin->lock cannot prevent this, as each instance takes a different lock. The locking issue is mostly disguised by the fact that the core usage of the vcap api runs under rtnl. However, the full rule dump in debugfs decodes rules straight from hardware (a READ command followed by a cache read) and runs outside rtnl, so it races a concurrent tc-flower rule write to another Super VCAP instance. Besides corrupting the dump, the read repopulates the shar...
In the Linux kernel, the following vulnerability has been resolved: net: microchip: vcap: fix races on the shared Super VCAP block The VCAP instances on a chip are not independent, yet they are locked independently. On sparx5 and lan969x the IS0 and IS2 instances are backed by the same Super VCAP hardware block and share its cache and command registers: every access drives the shared VCAP_SUPER_CTRL register and moves data through the shared cache registers. Accessing one instance therefore races with accessing another. The per-instance admin->lock cannot prevent this, as each instance takes a different lock. The locking issue is mostly disguised by the fact that the core usage of the vcap api runs under rtnl. However, the full rule dump in debugfs decodes rules straight from hardware (a READ command followed by a cache read) and runs outside rtnl, so it races a concurrent tc-flower rule write to another Super VCAP instance. Besides corrupting the dump, the read repopulates the sh
In the Linux kernel, the following vulnerability has been resolved: n ...
In the Linux kernel, the following vulnerability has been resolved: net: microchip: vcap: fix races on the shared Super VCAP block The VCAP instances on a chip are not independent, yet they are locked independently. On sparx5 and lan969x the IS0 and IS2 instances are backed by the same Super VCAP hardware block and share its cache and command registers: every access drives the shared VCAP_SUPER_CTRL register and moves data through the shared cache registers. Accessing one instance therefore races with accessing another. The per-instance admin->lock cannot prevent this, as each instance takes a different lock. The locking issue is mostly disguised by the fact that the core usage of the vcap api runs under rtnl. However, the full rule dump in debugfs decodes rules straight from hardware (a READ command followed by a cache read) and runs outside rtnl, so it races a concurrent tc-flower rule write to another Super VCAP instance. Besides corrupting the dump, the read repopulates the...
EPSS
5.5 Medium
CVSS3