From: "yukuai (C)" <yukuai3@huawei.com>
To: Ming Lei <ming.lei@redhat.com>
Cc: <josef@toxicpanda.com>, <axboe@kernel.dk>, <hch@infradead.org>,
<linux-block@vger.kernel.org>, <nbd@other.debian.org>,
<linux-kernel@vger.kernel.org>, <yi.zhang@huawei.com>
Subject: Re: [patch v8 3/7] nbd: check sock index in nbd_read_stat()
Date: Wed, 22 Sep 2021 20:21:26 +0800 [thread overview]
Message-ID: <3bfd595e-20a6-c4ab-b041-9bca28a4584f@huawei.com> (raw)
In-Reply-To: <YUr1v8zylPOFFXTO@T590>
On 2021/09/22 17:22, Ming Lei wrote:
> On Sun, Sep 19, 2021 at 06:34:28PM +0800, yukuai (C) wrote:
>> On 2021/09/16 17:33, Yu Kuai wrote:
>>> The sock that clent send request in nbd_send_cmd() and receive reply
>>> in nbd_read_stat() should be the same.
>>>
>>> Signed-off-by: Yu Kuai <yukuai3@huawei.com>
>>> ---
>>> drivers/block/nbd.c | 4 ++++
>>> 1 file changed, 4 insertions(+)
>>>
>>> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
>>> index 614c6ab2b8fe..c724a5bd7fa4 100644
>>> --- a/drivers/block/nbd.c
>>> +++ b/drivers/block/nbd.c
>>> @@ -746,6 +746,10 @@ static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
>>> ret = -ENOENT;
>>> goto out;
>>> }
>>> + if (cmd->index != index) {
>>> + dev_err(disk_to_dev(nbd->disk), "Unexpected reply %d from different sock %d (expected %d)",
>>> + tag, index, cmd->index);
>>> + }
>>> if (cmd->cmd_cookie != nbd_handle_to_cookie(handle)) {
>>> dev_err(disk_to_dev(nbd->disk), "Double reply on req %p, cmd_cookie %u, handle cookie %u\n",
>>> req, cmd->cmd_cookie, nbd_handle_to_cookie(handle));
>>>
>>
>> Hi, Ming
>>
>> Any suggestions about this patch?
>
> I think this one relies on nbd protocol between server and client, and
> does the protocol require both request and reply xmitted via same
> socket?
>
I searched nbd-server source code, and found that socket_read() and
send_reply->socket_write() are always come in pares and using the same
socket.
BTW, if server reply a read request from a unexpected sock, then
nbd_read_stat() might stuck in receiving the read data. And for worse,
nbd_read_stat() can mistake the normal reply message for the read data
afterwards and corrupt client.
Thanks,
Kuai
next prev parent reply other threads:[~2021-09-22 12:21 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-16 9:33 [patch v8 0/7] handle unexpected message from server Yu Kuai
2021-09-16 9:33 ` [patch v8 1/7] nbd: don't handle response without a corresponding request message Yu Kuai
2021-09-16 9:33 ` [patch v8 2/7] nbd: make sure request completion won't concurrent Yu Kuai
2021-09-16 9:33 ` [patch v8 3/7] nbd: check sock index in nbd_read_stat() Yu Kuai
2021-09-19 10:34 ` yukuai (C)
2021-09-22 9:22 ` Ming Lei
2021-09-22 12:12 ` Eric Blake
2021-09-22 12:21 ` yukuai (C) [this message]
2021-09-22 15:56 ` Wouter Verhelst
2021-09-23 0:29 ` Ming Lei
2021-09-16 9:33 ` [patch v8 4/7] nbd: don't start request if nbd_queue_rq() failed Yu Kuai
2021-09-16 12:48 ` Ming Lei
2021-09-16 9:33 ` [patch v8 5/7] nbd: clean up return value checking of sock_xmit() Yu Kuai
2021-09-16 12:49 ` Ming Lei
2021-09-16 9:33 ` [patch v8 6/7] nbd: partition nbd_read_stat() into nbd_read_reply() and nbd_handle_reply() Yu Kuai
2021-09-16 12:53 ` Ming Lei
2021-09-16 9:33 ` [patch v8 7/7] nbd: fix uaf in nbd_handle_reply() Yu Kuai
2021-09-16 12:58 ` Ming Lei
2021-09-16 13:10 ` yukuai (C)
2021-09-16 13:55 ` Ming Lei
2021-09-16 14:05 ` yukuai (C)
2021-09-16 14:18 ` [PATCH v9] " Yu Kuai
2021-09-17 3:33 ` Ming Lei
2021-10-17 13:09 ` Jens Axboe
2021-09-23 13:33 ` [patch v8 0/7] handle unexpected message from server yukuai (C)
2021-09-29 12:54 ` yukuai (C)
2021-10-08 7:17 ` yukuai (C)
2021-10-15 8:19 ` yukuai (C)
2021-10-15 16:08 ` Josef Bacik
2021-10-17 13:09 ` Jens Axboe
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