[PATCH 1/3] md/raid10: fix slab-out-of-bounds in md_bitmap_get_counter

[linan666]

From: Li Nan <linan122@xxxxxxxxxx>

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.

Return directly if err is -EINVAL.

Fixes: ef4256733506 ("md/bitmap: optimise scanning of empty bitmaps.")
Signed-off-by: Li Nan <linan122@xxxxxxxxxx>
---
 drivers/md/md-bitmap.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index 920bb68156d2..0b41ef422da7 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -1388,6 +1388,8 @@ __acquires(bitmap->lock)
 	int err;
 
 	err = md_bitmap_checkpage(bitmap, page, create, 0);
+	if (err == -EINVAL)
+		return NULL;
 
 	if (bitmap->bp[page].hijacked ||
 	    bitmap->bp[page].map == NULL)
-- 
2.31.1