Описание
In the Linux kernel, the following vulnerability has been resolved:
x86/fpu: Keep xfd_state in sync with MSR_IA32_XFD
Commit 672365477ae8 ("x86/fpu: Update XFD state where required") and
commit 8bf26758ca96 ("x86/fpu: Add XFD state to fpstate") introduced a
per CPU variable xfd_state to keep the MSR_IA32_XFD value cached, in
order to avoid unnecessary writes to the MSR.
On CPU hotplug MSR_IA32_XFD is reset to the init_fpstate.xfd, which
wipes out any stale state. But the per CPU cached xfd value is not
reset, which brings them out of sync.
As a consequence a subsequent xfd_update_state() might fail to update
the MSR which in turn can result in XRSTOR raising a #NM in kernel
space, which crashes the kernel.
To fix this, introduce xfd_set_state() to write xfd_state together
with MSR_IA32_XFD, and use it in all places that set MSR_IA32_XFD.
In the Linux kernel, the following vulnerability has been resolved:
x86/fpu: Keep xfd_state in sync with MSR_IA32_XFD
The Linux kernel CVE team has assigned CVE-2024-35801 to this issue.
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024051738-CVE-2024-35801-8038@gregkh/T
Отчет
Red Hat has evaluated this vulnerability as having a Low severity impact because triggering the condition requires CPU hotplug operations on hardware platforms supporting extended feature disable (XFD). Unprivileged local users cannot perform CPU hotplug actions, requiring privileged access or specific hypervisor-level interventions to initiate the event that leads to kernel instability. As a result, the risk of unprivileged denial-of-service in typical enterprise environments remains minimal.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| 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-rt | Fixed | RHSA-2024:5102 | 08.08.2024 |
| Red Hat Enterprise Linux 8 | kernel | Fixed | RHSA-2024:5101 | 08.08.2024 |
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2024:9315 | 12.11.2024 |
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2024:9315 | 12.11.2024 |
| Red Hat Enterprise Linux 9.4 Extended Update Support | kernel | Fixed | RHSA-2025:2490 | 10.03.2025 |
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Дополнительная информация
Статус:
EPSS
5.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: x86/fpu: Keep xfd_state in sync with MSR_IA32_XFD Commit 672365477ae8 ("x86/fpu: Update XFD state where required") and commit 8bf26758ca96 ("x86/fpu: Add XFD state to fpstate") introduced a per CPU variable xfd_state to keep the MSR_IA32_XFD value cached, in order to avoid unnecessary writes to the MSR. On CPU hotplug MSR_IA32_XFD is reset to the init_fpstate.xfd, which wipes out any stale state. But the per CPU cached xfd value is not reset, which brings them out of sync. As a consequence a subsequent xfd_update_state() might fail to update the MSR which in turn can result in XRSTOR raising a #NM in kernel space, which crashes the kernel. To fix this, introduce xfd_set_state() to write xfd_state together with MSR_IA32_XFD, and use it in all places that set MSR_IA32_XFD.
In the Linux kernel, the following vulnerability has been resolved: x86/fpu: Keep xfd_state in sync with MSR_IA32_XFD Commit 672365477ae8 ("x86/fpu: Update XFD state where required") and commit 8bf26758ca96 ("x86/fpu: Add XFD state to fpstate") introduced a per CPU variable xfd_state to keep the MSR_IA32_XFD value cached, in order to avoid unnecessary writes to the MSR. On CPU hotplug MSR_IA32_XFD is reset to the init_fpstate.xfd, which wipes out any stale state. But the per CPU cached xfd value is not reset, which brings them out of sync. As a consequence a subsequent xfd_update_state() might fail to update the MSR which in turn can result in XRSTOR raising a #NM in kernel space, which crashes the kernel. To fix this, introduce xfd_set_state() to write xfd_state together with MSR_IA32_XFD, and use it in all places that set MSR_IA32_XFD.
In the Linux kernel, the following vulnerability has been resolved: x ...
In the Linux kernel, the following vulnerability has been resolved: x86/fpu: Keep xfd_state in sync with MSR_IA32_XFD Commit 672365477ae8 ("x86/fpu: Update XFD state where required") and commit 8bf26758ca96 ("x86/fpu: Add XFD state to fpstate") introduced a per CPU variable xfd_state to keep the MSR_IA32_XFD value cached, in order to avoid unnecessary writes to the MSR. On CPU hotplug MSR_IA32_XFD is reset to the init_fpstate.xfd, which wipes out any stale state. But the per CPU cached xfd value is not reset, which brings them out of sync. As a consequence a subsequent xfd_update_state() might fail to update the MSR which in turn can result in XRSTOR raising a #NM in kernel space, which crashes the kernel. To fix this, introduce xfd_set_state() to write xfd_state together with MSR_IA32_XFD, and use it in all places that set MSR_IA32_XFD.
EPSS
5.5 Medium
CVSS3