From: Yu Kuai Date: Tue, 2 Nov 2021 01:52:35 +0000 (+0800) Subject: nbd: fix possible overflow for 'first_minor' in nbd_dev_add() X-Git-Tag: v6.1-rc5~2682^2~27 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=940c264984fd1457918393c49674f6b39ee16506;p=platform%2Fkernel%2Flinux-starfive.git nbd: fix possible overflow for 'first_minor' in nbd_dev_add() 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: b0d9111a2d53 ("nbd: use an idr to keep track of nbd devices") Signed-off-by: Yu Kuai Reviewed-by: Josef Bacik Link: https://lore.kernel.org/r/20211102015237.2309763-3-yebin10@huawei.com Signed-off-by: Jens Axboe --- diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 29f9ac8..a5e3ee2 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1808,11 +1808,11 @@ static struct nbd_device *nbd_dev_add(int index, unsigned int refs) 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; }