Messages in this thread | | | Subject | Re: [patch v8 3/7] nbd: check sock index in nbd_read_stat() | From | "yukuai (C)" <> | Date | Wed, 22 Sep 2021 20:21:26 +0800 |
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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
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