CVE-2021-47429 Affecting kernel-source package, versions <5.14.21-150500.55.68.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.04% (11th percentile)

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  • Snyk IDSNYK-SLES155-KERNELSOURCE-7375643
  • published26 Jun 2024
  • disclosed25 Jun 2024

Introduced: 25 Jun 2024

CVE-2021-47429  (opens in a new tab)

How to fix?

Upgrade SLES:15.5 kernel-source to version 5.14.21-150500.55.68.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-source package and not the kernel-source package as distributed by SLES. See How to fix? for SLES:15.5 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

powerpc/64s: Fix unrecoverable MCE calling async handler from NMI

The machine check handler is not considered NMI on 64s. The early handler is the true NMI handler, and then it schedules the machine_check_exception handler to run when interrupts are enabled.

This works fine except the case of an unrecoverable MCE, where the true NMI is taken when MSR[RI] is clear, it can not recover, so it calls machine_check_exception directly so something might be done about it.

Calling an async handler from NMI context can result in irq state and other things getting corrupted. This can also trigger the BUG at arch/powerpc/include/asm/interrupt.h:168 BUG_ON(!arch_irq_disabled_regs(regs) && !(regs->msr & MSR_EE));

Fix this by making an _async version of the handler which is called in the normal case, and a NMI version that is called for unrecoverable interrupts.

CVSS Scores

version 3.1