Messages in this thread Patch in this message | | | From | Sasha Levin <> | Subject | [PATCH AUTOSEL 5.4 8/8] block: Fix wrong offset in bio_truncate() | Date | Sat, 22 Jan 2022 19:13:23 -0500 |
| |
From: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
[ Upstream commit 3ee859e384d453d6ac68bfd5971f630d9fa46ad3 ]
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: Sasha Levin <sashal@kernel.org> --- block/bio.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/block/bio.c b/block/bio.c index cb38d6f3acceb..1c52d0196e15c 100644 --- a/block/bio.c +++ b/block/bio.c @@ -569,7 +569,8 @@ void bio_truncate(struct bio *bio, unsigned new_size) 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; -- 2.34.1
| |