Commit 374fb914 authored May 15, 2023 by Li Nan Committed by Greg Kroah-Hartman Aug 11, 2023

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



[ Upstream commit 301867b1c16805aebbc306aafa6ecdc68b73c7e5 ]

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: ef425673 ("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


Signed-off-by: Sasha Levin <sashal@kernel.org>

parent b7e38923

drivers/md/md-bitmap.c

+9 −8

Original line number	Diff line number	Diff line
		@@ -53,14 +53,7 @@ __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;

		@@ -1368,6 +1361,14 @@ __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 \|\|