Re: [PATCH v2] nbd: fix uaf in nbd_open
- To: Li Lingfeng <lilingfeng@huaweicloud.com>
- Cc: linux-kernel@vger.kernel.org, hch@lst.de, linux-block@vger.kernel.org, nbd@other.debian.org, axboe@kernel.dk, chaitanya.kulkarni@wdc.com, yukuai1@huaweicloud.com, houtao1@huawei.com, yi.zhang@huawei.com, yangerkun@huawei.com, lilingfeng3@huawei.com
- Subject: Re: [PATCH v2] nbd: fix uaf in nbd_open
- From: Josef Bacik <josef@toxicpanda.com>
- Date: Tue, 7 Nov 2023 10:05:20 -0500
- Message-id: <[🔎] 20231107150520.GA3913709@perftesting>
- In-reply-to: <20231107103435.2074904-1-lilingfeng@huaweicloud.com>
- References: <20231107103435.2074904-1-lilingfeng@huaweicloud.com>
On Tue, Nov 07, 2023 at 06:34:35PM +0800, Li Lingfeng wrote:
> From: Li Lingfeng <lilingfeng3@huawei.com>
>
> Commit 4af5f2e03013 ("nbd: use blk_mq_alloc_disk and
> blk_cleanup_disk") cleans up disk by blk_cleanup_disk() and it won't set
> disk->private_data as NULL as before. UAF may be triggered in nbd_open()
> if someone tries to open nbd device right after nbd_put() since nbd has
> been free in nbd_dev_remove().
>
> Fix this by implementing ->free_disk and free private data in it.
>
> Fixes: 4af5f2e03013 ("nbd: use blk_mq_alloc_disk and blk_cleanup_disk")
> Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Thanks,
Josef
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