From 3330b965374b4879d35529716c2aac0e6326c225 Mon Sep 17 00:00:00 2001 From: OGAWA Hirofumi Date: Sun, 9 Jan 2022 18:36:43 +0900 Subject: [PATCH] block: Fix wrong offset in bio_truncate() 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 Reviewed-by: Ming Lei Link: https://lore.kernel.org/r/875yqt1c9g.fsf@mail.parknet.co.jp Signed-off-by: Jens Axboe --- block/bio.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/block/bio.c b/block/bio.c index 0d400ba2dbd18..4312a8085396b 100644 --- a/block/bio.c +++ b/block/bio.c @@ -569,7 +569,8 @@ static 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; -- 2.39.5