fs/ntfs3: reject index allocation if $BITMAP is empty but blocks exist

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[ Upstream commit 0dc7117da8 ]

Index allocation requires at least one bit in the $BITMAP attribute to
track usage of index entries. If the bitmap is empty while index blocks
are already present, this reflects on-disk corruption.

syzbot triggered this condition using a malformed NTFS image. During a
rename() operation involving a long filename (which spans multiple
index entries), the empty bitmap allowed the name to be added without
valid tracking. Subsequent deletion of the original entry failed with
-ENOENT, due to unexpected index state.

Reject such cases by verifying that the bitmap is not empty when index
blocks exist.

Reported-by: syzbot+b0373017f711c06ada64@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=b0373017f711c06ada64
Fixes: d99208b919 ("fs/ntfs3: cancle set bad inode after removing name fails")
Tested-by: syzbot+b0373017f711c06ada64@syzkaller.appspotmail.com
Signed-off-by: Moon Hee Lee <moonhee.lee.ca@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Moon Hee Lee 2025-07-22 10:40:16 -07:00 • committed by Greg Kroah-Hartman

parent 5aa5799d16

commit 039ddf353c

1 changed files with 10 additions and 0 deletions

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fs/ntfs3/index.c

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