| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.15 171/171] block: Fix wrong offset in bio_truncate() | Date | Mon, 31 Jan 2022 11:57:16 +0100 |
| |
From: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
commit 3ee859e384d453d6ac68bfd5971f630d9fa46ad3 upstream.
bio_truncate() clears the buffer outside of last block of bdev, however current bio_truncate() is using the wrong offset of page. So it can return the uninitialized data.
This happened when both of truncated/corrupted FS and userspace (via bdev) are trying to read the last of bdev.
Reported-by: syzbot+ac94ae5f68b84197f41c@syzkaller.appspotmail.com Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Reviewed-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/875yqt1c9g.fsf@mail.parknet.co.jp Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- block/bio.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/block/bio.c +++ b/block/bio.c @@ -567,7 +567,8 @@ void bio_truncate(struct bio *bio, unsig offset = new_size - done; else offset = 0; - zero_user(bv.bv_page, offset, bv.bv_len - offset); + zero_user(bv.bv_page, bv.bv_offset + offset, + bv.bv_len - offset); truncated = true; } done += bv.bv_len;
|