Описание
In the Linux kernel, the following vulnerability has been resolved:
ata: libahci: clear PxCLBU and PxFBU for AHCI_HFLAG_32BIT_ONLY
A user reported that commit 105c42566a55 ("ata: ahci: force 32-bit DMA for
JMicron JMB582/JMB585") made the JMicron JMB585 unusable on his board.
The failure is seen as soon as the ahci driver is probed, and booting with
iommu=off does not solve the problem.
Looking at the AHCI specification, PxCLBU and PxFBU are both read only '0'
for HBAs that do not support 64-bit addressing.
For HBAs that do support 64-bit addressing, the registers are read write,
with a reset value that is Implementation Specific.
When using the AHCI_HFLAG_32BIT_ONLY flag, the HBA does support 64-bit
addressing, and a 32-bit DMA mask is set by simply clearing HOST_CAP_64.
Thus, in this case, we need to explicitly clear the registers to 0.
A flaw was found in the Linux kernel's libahci driver. This issue can lead to a Denial of Service (DoS) when initializing storage controllers configured to use 32-bit Direct Memory Access (DMA). Because the driver fails to clear the upper 32-bit memory address registers on hardware that physically supports 64-bit addressing, uninitialized values remain in those registers. Consequently, a local user working with affected storage hardware may trigger device probe failures, rendering the storage controller and attached drives unusable.
Отчет
This vulnerability is rated Moderate severity for Red Hat Enterprise Linux because exploitation is restricted to systems utilizing specific storage controller hardware and requires local interaction to trigger driver initialization failures. Standard enterprise installations typically deploy well-tested enterprise-grade host bus adapters or virtualized disk interfaces, meaning consumer-grade chipsets that enforce 32-bit addressing while possessing 64-bit capabilities are uncommon in production environments. Even when vulnerable host adapters are present, the defect manifests strictly as an operational failure during controller detection rather than leading to arbitrary code execution or privilege escalation.
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 | 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:
7 High
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: ata: libahci: clear PxCLBU and PxFBU for AHCI_HFLAG_32BIT_ONLY A user reported that commit 105c42566a55 ("ata: ahci: force 32-bit DMA for JMicron JMB582/JMB585") made the JMicron JMB585 unusable on his board. The failure is seen as soon as the ahci driver is probed, and booting with iommu=off does not solve the problem. Looking at the AHCI specification, PxCLBU and PxFBU are both read only '0' for HBAs that do not support 64-bit addressing. For HBAs that do support 64-bit addressing, the registers are read write, with a reset value that is Implementation Specific. When using the AHCI_HFLAG_32BIT_ONLY flag, the HBA does support 64-bit addressing, and a 32-bit DMA mask is set by simply clearing HOST_CAP_64. Thus, in this case, we need to explicitly clear the registers to 0.
In the Linux kernel, the following vulnerability has been resolved: ata: libahci: clear PxCLBU and PxFBU for AHCI_HFLAG_32BIT_ONLY A user reported that commit 105c42566a55 ("ata: ahci: force 32-bit DMA for JMicron JMB582/JMB585") made the JMicron JMB585 unusable on his board. The failure is seen as soon as the ahci driver is probed, and booting with iommu=off does not solve the problem. Looking at the AHCI specification, PxCLBU and PxFBU are both read only '0' for HBAs that do not support 64-bit addressing. For HBAs that do support 64-bit addressing, the registers are read write, with a reset value that is Implementation Specific. When using the AHCI_HFLAG_32BIT_ONLY flag, the HBA does support 64-bit addressing, and a 32-bit DMA mask is set by simply clearing HOST_CAP_64. Thus, in this case, we need to explicitly clear the registers to 0.
ata: libahci: clear PxCLBU and PxFBU for AHCI_HFLAG_32BIT_ONLY
In the Linux kernel, the following vulnerability has been resolved: a ...
In the Linux kernel, the following vulnerability has been resolved: ata: libahci: clear PxCLBU and PxFBU for AHCI_HFLAG_32BIT_ONLY A user reported that commit 105c42566a55 ("ata: ahci: force 32-bit DMA for JMicron JMB582/JMB585") made the JMicron JMB585 unusable on his board. The failure is seen as soon as the ahci driver is probed, and booting with iommu=off does not solve the problem. Looking at the AHCI specification, PxCLBU and PxFBU are both read only '0' for HBAs that do not support 64-bit addressing. For HBAs that do support 64-bit addressing, the registers are read write, with a reset value that is Implementation Specific. When using the AHCI_HFLAG_32BIT_ONLY flag, the HBA does support 64-bit addressing, and a 32-bit DMA mask is set by simply clearing HOST_CAP_64. Thus, in this case, we need to explicitly clear the registers to 0.
7 High
CVSS3