diff options
| author | Jiangfeng Xiao <xiaojiangfeng@huawei.com> | 2024-01-23 09:45:59 +0800 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2024-02-05 22:57:26 +1100 |
| commit | 4a7aee96200ad281a5cc4cf5c7a2e2a49d2b97b0 (patch) | |
| tree | 2095efb2411626454e0e15cc5277bb392fa4e355 /arch/powerpc | |
| parent | a038a3ff8c6582404834852c043dadc73a5b68b4 (diff) | |
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.
Fixes: 663c0c9496a6 ("powerpc/kasan: Fix shadow area set up for modules.")
Signed-off-by: Jiangfeng Xiao <xiaojiangfeng@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/1705974359-43790-1-git-send-email-xiaojiangfeng@huawei.com
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/mm/kasan/init_32.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/powerpc/mm/kasan/init_32.c b/arch/powerpc/mm/kasan/init_32.c index a70828a6d935..aa9aa11927b2 100644 --- a/arch/powerpc/mm/kasan/init_32.c +++ b/arch/powerpc/mm/kasan/init_32.c @@ -64,6 +64,7 @@ int __init __weak kasan_init_region(void *start, size_t size) if (ret) return ret; + k_start = k_start & PAGE_MASK; block = memblock_alloc(k_end - k_start, PAGE_SIZE); if (!block) return -ENOMEM; |