From: Ye Bin <yebin10@huawei.com>
To: <josef@toxicpanda.com>, <axboe@kernel.dk>,
<linux-block@vger.kernel.org>, <nbd@other.debian.org>
Cc: <linux-kernel@vger.kernel.org>, Yu Kuai <yukuai3@huawei.com>
Subject: [PATCH -next v4 2/4] nbd: fix possible overflow for 'first_minor' in nbd_dev_add()
Date: Tue, 2 Nov 2021 09:52:35 +0800 [thread overview]
Message-ID: <20211102015237.2309763-3-yebin10@huawei.com> (raw)
In-Reply-To: <20211102015237.2309763-1-yebin10@huawei.com>
From: Yu Kuai <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 678ee2688f63..cc32b5bc0f49 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -1803,11 +1803,11 @@ 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;
}
--
2.31.1
next prev parent reply other threads:[~2021-11-02 1:39 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-02 1:52 [PATCH -next v4 0/4] Fix hungtask when nbd_config_put and sanity check for first_minor Ye Bin
2021-11-02 1:52 ` [PATCH -next v4 1/4] nbd: fix max value for 'first_minor' Ye Bin
2021-11-02 1:52 ` Ye Bin [this message]
2021-11-02 1:52 ` [PATCH -next v4 3/4] nbd: Fix incorrect error handle when first_minor is illegal in nbd_dev_add Ye Bin
2021-11-02 1:52 ` [PATCH -next v4 4/4] nbd: Fix hungtask when nbd_config_put Ye Bin
2021-11-02 13:04 ` [PATCH -next v4 0/4] Fix hungtask when nbd_config_put and sanity check for first_minor Josef Bacik
2021-11-02 16:50 ` Jens Axboe
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