CVE-2024-26847

/// Technical description

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

powerpc/rtas: use correct function name for resetting TCE tables

The PAPR spec spells the function name as

"ibm,reset-pe-dma-windows"

but in practice firmware uses the singular form:

"ibm,reset-pe-dma-window"

in the device tree. Since we have the wrong spelling in the RTAS

function table, reverse lookups (token -> name) fail and warn:

unexpected failed lookup for token 86

WARNING: CPU: 1 PID: 545 at arch/powerpc/kernel/rtas.c:659 __do_enter_rtas_trace+0x2a4/0x2b4

CPU: 1 PID: 545 Comm: systemd-udevd Not tainted 6.8.0-rc4 #30

Hardware name: IBM,9105-22A POWER10 (raw) 0x800200 0xf000006 of:IBM,FW1060.00 (NL1060_028) hv:phyp pSeries

NIP [c0000000000417f0] __do_enter_rtas_trace+0x2a4/0x2b4

LR [c0000000000417ec] __do_enter_rtas_trace+0x2a0/0x2b4

Call Trace:

__do_enter_rtas_trace+0x2a0/0x2b4 (unreliable)

rtas_call+0x1f8/0x3e0

enable_ddw.constprop.0+0x4d0/0xc84

dma_iommu_dma_supported+0xe8/

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References