Описание
In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Avoid consuming a stale esr value when SError occur
When any exception other than an IRQ occurs, the CPU updates the ESR_EL2
register with the exception syndrome. An SError may also become pending,
and will be synchronised by KVM. KVM notes the exception type, and whether
an SError was synchronised in exit_code.
When an exception other than an IRQ occurs, fixup_guest_exit() updates
vcpu->arch.fault.esr_el2 from the hardware register. When an SError was
synchronised, the vcpu esr value is used to determine if the exception
was due to an HVC. If so, ELR_EL2 is moved back one instruction. This
is so that KVM can process the SError first, and re-execute the HVC if
the guest survives the SError.
But if an IRQ synchronises an SError, the vcpu's esr value is stale.
If the previous non-IRQ exception was an HVC, KVM will corrupt ELR_EL2,
causing an unrelated guest instruction to be executed twice.
Check ARM_EXCEPTION_CODE() before messing with ELR_EL2, IRQs don't
update this register so don't need to check.
A flaw was found in the Linux kernel's Kernel-based Virtual Machine (KVM) subsystem for ARM64 architecture. When an interrupt request synchronizes a system error, the hypervisor evaluates a stale exception syndrome register rather than verifying the actual exception code. If the prior exception was a hypervisor call, this mishandling corrupts the guest return register and causes unrelated guest instructions to execute twice. A local user or guest virtual machine can trigger this behavior, leading to unexpected execution flow, system instability, or a denial of service (DoS).
Отчет
This vulnerability is rated as having a Low impact for Red Hat Enterprise Linux because exploitation requires a precise timing condition involving asynchronous hardware errors during guest execution on ARM64 virtualization hosts. The flaw only affects systems running KVM hypervisors on 64-bit ARM architecture, with consequences primarily limited to guest instruction re-execution and potential virtual machine instability. Non-ARM64 platforms such as x86_64, s390x, and ppc64le, as well as systems not running KVM guests, are completely unaffected.
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 | 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 | Fix deferred |
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Дополнительная информация
Статус:
EPSS
4.4 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Avoid consuming a stale esr value when SError occur When any exception other than an IRQ occurs, the CPU updates the ESR_EL2 register with the exception syndrome. An SError may also become pending, and will be synchronised by KVM. KVM notes the exception type, and whether an SError was synchronised in exit_code. When an exception other than an IRQ occurs, fixup_guest_exit() updates vcpu->arch.fault.esr_el2 from the hardware register. When an SError was synchronised, the vcpu esr value is used to determine if the exception was due to an HVC. If so, ELR_EL2 is moved back one instruction. This is so that KVM can process the SError first, and re-execute the HVC if the guest survives the SError. But if an IRQ synchronises an SError, the vcpu's esr value is stale. If the previous non-IRQ exception was an HVC, KVM will corrupt ELR_EL2, causing an unrelated guest instruction to be executed twice. Check ARM_EXCEP...
In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Avoid consuming a stale esr value when SError occur When any exception other than an IRQ occurs, the CPU updates the ESR_EL2 register with the exception syndrome. An SError may also become pending, and will be synchronised by KVM. KVM notes the exception type, and whether an SError was synchronised in exit_code. When an exception other than an IRQ occurs, fixup_guest_exit() updates vcpu->arch.fault.esr_el2 from the hardware register. When an SError was synchronised, the vcpu esr value is used to determine if the exception was due to an HVC. If so, ELR_EL2 is moved back one instruction. This is so that KVM can process the SError first, and re-execute the HVC if the guest survives the SError. But if an IRQ synchronises an SError, the vcpu's esr value is stale. If the previous non-IRQ exception was an HVC, KVM will corrupt ELR_EL2, causing an unrelated guest instruction to be executed twice. Check ARM_EXC
In the Linux kernel, the following vulnerability has been resolved: K ...
In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Avoid consuming a stale esr value when SError occur When any exception other than an IRQ occurs, the CPU updates the ESR_EL2 register with the exception syndrome. An SError may also become pending, and will be synchronised by KVM. KVM notes the exception type, and whether an SError was synchronised in exit_code. When an exception other than an IRQ occurs, fixup_guest_exit() updates vcpu->arch.fault.esr_el2 from the hardware register. When an SError was synchronised, the vcpu esr value is used to determine if the exception was due to an HVC. If so, ELR_EL2 is moved back one instruction. This is so that KVM can process the SError first, and re-execute the HVC if the guest survives the SError. But if an IRQ synchronises an SError, the vcpu's esr value is stale. If the previous non-IRQ exception was an HVC, KVM will corrupt ELR_EL2, causing an unrelated guest instruction to be executed twice. Check ARM_...
Уязвимость функции fixup_guest_exit компонента arm64 подсистемы виртуализации KVM ядра операционной системы Linux, позволяющая нарушителю вызвать отказ в обслуживании
EPSS
4.4 Medium
CVSS3