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md/raid10: check slab-out-of-bounds in md_bitmap_get_counter

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If we write a large number to md/bitmap_set_bits, md_bitmap_checkpage()
will return -EINVAL because 'page >= bitmap->pages', but the return value
was not checked immediately in md_bitmap_get_counter() in order to set
*blocks value and slab-out-of-bounds occurs.

Move check of 'page >= bitmap->pages' to md_bitmap_get_counter() and
return directly if true.

Fixes: ef4256733506 ("md/bitmap: optimise scanning of empty bitmaps.")
Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230515134808.3936750-2-linan666@huaweicloud.com
This commit is contained in:
Li Nan 2023-05-15 21:48:05 +08:00 committed by Song Liu
parent 3de13550a2
commit 301867b1c1
1 changed files with 9 additions and 8 deletions
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17
drivers/md/md-bitmap.c
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@ -54,14 +54,7 @@ __acquires(bitmap->lock)
{
unsigned char *mappage;
if (page >= bitmap->pages) {
/* This can happen if bitmap_start_sync goes beyond
* End-of-device while looking for a whole page.
* It is harmless.
*/
return -EINVAL;
}
WARN_ON_ONCE(page >= bitmap->pages);
if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
return 0;
@ -1387,6 +1380,14 @@ __acquires(bitmap->lock)
sector_t csize;
int err;
if (page >= bitmap->pages) {
/*
* This can happen if bitmap_start_sync goes beyond
* End-of-device while looking for a whole page or
* user set a huge number to sysfs bitmap_set_bits.
*/
return NULL;
}
err = md_bitmap_checkpage(bitmap, page, create, 0);
if (bitmap->bp[page].hijacked ||