1.6 KiB
CVE-2024-26712
Description
In the Linux kernel, the following vulnerability has been resolved:powerpc/kasan: Fix addr error caused by page alignmentIn kasan_init_region, when k_start is not page aligned, at the begin offor loop, k_cur = k_start & PAGE_MASK is less than k_start, and thenva = 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 bymemblock_alloc, which will not be reserved by memblock_reserve later, itwill 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 beforememblock_alloc() to ensure the validity of the VA address.
POC
Reference
No PoCs from references.