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high7.8

CVE-2024-26712

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 i…

Impact

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

VendorProductAffected versions
LinuxLinux 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
Version 6.8
DebianDebian Linux
Version 10.0

References