From: OGAWA Hirofumi hirofumi@mail.parknet.co.jp
mainline inclusion from mainline-v5.17-rc1 commit 3ee859e384d453d6ac68bfd5971f630d9fa46ad3 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I6GTUI CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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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: Yu Kuai yukuai3@huawei.com Reviewed-by: Hou Tao houtao1@huawei.com Signed-off-by: Yongqiang Liu liuyongqiang13@huawei.com --- block/bio.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/block/bio.c b/block/bio.c index a1c74f10d604..9d70ebe4122c 100644 --- a/block/bio.c +++ b/block/bio.c @@ -578,7 +578,8 @@ 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;