CVE-2024-26712: powerpc/kasan: Fix addr error caused by page alignment

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-04-03 · updated 2026-08-04

Description

In the Linux kernel, the following vulnerability has been resolved: powerpc/kasan: Fix addr error caused by page alignment In kasan_init_region, when k_start is not page aligned, at the begin of for loop, k_cur = k_start & PAGE_MASK is less than k_start, and then `va = block + k_cur - k_start` is less than block, the addr va is invalid, because the memory address space from va to block is not alloced by memblock_alloc, which will not be reserved by memblock_reserve later, it will be used by other places. As a result, memory overwriting occurs. for example: int __init __weak kasan_init_region(void *start, size_t size) { [...] /* if say block(dcd97000) k_start(feef7400) k_end(feeff3fe) */ block = memblock_alloc(k_end - k_start, PAGE_SIZE); [...] for (k_cur = k_start & PAGE_MASK; k_cur < k_end; k_cur += PAGE_SIZE) { /* at the begin of for loop * block(dcd97000) va(dcd96c00) k_cur(feef7000) k_start(feef7400) * va(dcd96c00) is less than block(dcd97000), va is invalid */ void *va = block + k_cur - k_start; [...] } [...] } Therefore, page alignment is performed on k_start before memblock_alloc() to ensure the validity of the VA address.

Affected products

Debian Linux: 10.0
Linux kernel: from 5.4 before 5.10.210; from 5.11 before 5.15.149; from 5.16 before 6.1.79; from 6.2 before 6.6.18; from 6.7 before 6.7.6; 6.8-rc1, 6.8-rc2, 6.8-rc3, 6.8-rc4 — fixed in 5.10.210, 5.15.149, 6.1.79, 6.6.18, 6.7.6

How to fix

Upgrade to a fixed version: Linux kernel 5.10.210, 5.15.149, 6.1.79, 6.6.18. Check the vendor advisory for mitigations.

References

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