Re: [PATCH v2 1/4] md/raid10: fix slab-out-of-bounds in md_bitmap_get_counter
From: Song Liu <song@kernel.org>
Date: 2023-05-13 01:05:43
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On Fri, May 5, 2023 at 6:24 PM [off-list ref] wrote:
quoted hunk ↗ jump to hunk
From: Li Nan <redacted> 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 <redacted> Reviewed-by: Yu Kuai <redacted> --- 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;
This logic is error prone. Since we are on it, let's fix it better. Specifically, we can move "page >= bitmap->pages" check out of md_bitmap_checkpage(). (and fix the call site in md_bitmap_resize for clustered md). Also, could you please add a mdadm test for this issue? Thanks, Song
if (bitmap->bp[page].hijacked ||
bitmap->bp[page].map == NULL)
--
2.31.1