From: Yu Kuai <yukuai3@huawei.com>
To: <josef@toxicpanda.com>, <axboe@kernel.dk>, <paskripkin@gmail.com>
Cc: <linux-block@vger.kernel.org>, <nbd@other.debian.org>,
<linux-kernel@vger.kernel.org>, <yukuai3@huawei.com>,
<yi.zhang@huawei.com>, <luomeng12@huawei.com>
Subject: [PATCH 2/2] nbd: fix possible overflow for 'first_minor' in nbd_dev_add()
Date: Thu, 21 Oct 2021 20:29:36 +0800 [thread overview]
Message-ID: <20211021122936.758221-3-yukuai3@huawei.com> (raw)
In-Reply-To: <20211021122936.758221-1-yukuai3@huawei.com>
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 <yukuai3@huawei.com>
---
drivers/block/nbd.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 8f2c17a33c5b..03a10a87500d 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 > 0xfffff) {
+ if (disk->first_minor < index || disk->first_minor > 0xfffff) {
err = -EINVAL;
goto out_free_idr;
}
--
2.31.1
next prev parent reply other threads:[~2021-10-21 12:17 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-21 12:29 [PATCH 0/2] nbd: fix sanity check for first_minor Yu Kuai
2021-10-21 12:29 ` [PATCH 1/2] nbd: fix max value for 'first_minor' Yu Kuai
2021-10-21 12:29 ` Yu Kuai [this message]
2021-10-21 12:35 ` [PATCH 0/2] nbd: fix sanity check for first_minor Pavel Skripkin
2021-10-21 13:13 ` yukuai (C)
2021-10-21 13:37 ` yukuai (C)
2021-10-25 13:41 ` yukuai (C)
2021-11-01 8:06 ` yukuai (C)
2021-10-21 16:47 ` Pavel Skripkin
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