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4a7aee9620
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.
Fixes:
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---|---|---|
.. | ||
book3s32 | ||
book3s64 | ||
kasan | ||
nohash | ||
ptdump | ||
cacheflush.c | ||
copro_fault.c | ||
dma-noncoherent.c | ||
drmem.c | ||
fault.c | ||
hugetlbpage.c | ||
init-common.c | ||
init_32.c | ||
init_64.c | ||
ioremap.c | ||
ioremap_32.c | ||
ioremap_64.c | ||
maccess.c | ||
Makefile | ||
mem.c | ||
mmu_context.c | ||
mmu_decl.h | ||
numa.c | ||
pageattr.c | ||
pgtable-frag.c | ||
pgtable.c | ||
pgtable_32.c | ||
pgtable_64.c |