Commit 16699a73 authored by Yu Kuai's avatar Yu Kuai Committed by Li Nan
Browse files

nbd: fix possible overflow for 'first_minor' in nbd_dev_add() 

stable inclusion
from stable-v5.10.170
commit 2e0c3e43ebb99c2b495229f8fade4c043fbd06a5
category: bugfix
bugzilla: 188217

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2e0c3e43ebb99c2b495229f8fade4c043fbd06a5



----------------------------------------

commit 940c2649 upstream.

If 'part_shift' is not zero, then 'index << part_shift' might
overflow to a value that is not greater than '0xfffff', then sysfs
might complains about duplicate creation.

Fixes: b0d9111a ("nbd: use an idr to keep track of nbd devices")
Signed-off-by: default avatarYu Kuai <yukuai3@huawei.com>
Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20211102015237.2309763-3-yebin10@huawei.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarWen Yang <wenyang.linux@foxmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarZhong Jinghua <zhongjinghua@huawei.com>
Signed-off-by: default avatarLi Nan <linan122@huawei.com>
parent ddaeb045

drivers/block/nbd.c

+3 −3
Original line number Diff line number Diff line
@@ -1877,11 +1877,11 @@ static int nbd_dev_add(int index) 
	disk->major = NBD_MAJOR;



	/* Too big first_minor can cause duplicate creation of

	 * sysfs files/links, since MKDEV() expect that the max bits of

	 * first_minor is 20.

	 * sysfs files/links, since index << part_shift might overflow, or

	 * MKDEV() expect that the max bits of first_minor is 20.

	 */

	disk->first_minor = index << part_shift;

	if (disk->first_minor > MINORMASK) {

	if (disk->first_minor < index || disk->first_minor > MINORMASK) {

		err = -EINVAL;

		goto out_free_idr;

	}