How to Create SslStream for a non-blocking async socket

Question

I have a multi threaded async System.Net.Socket which listens on a port. I don't have any problem if I get a request from HTTP, but recently I had to add https support to my application.

The client gave me an .arm certification file. It has base-64 encoded ASCII data in it. The file name is cert.arm and it is stored in the root of my solution folder.

Here is what I do till now to use that certificate:

using System;
using System.Net;
using System.Threading;
using System.Net.Security;
using System.Net.Sockets;
using System.Security.Cryptography.X509Certificates;
using System.Text;

namespace SocketExample
{
    public class StackOverFlow
    {
        public static ManualResetEvent _manualResetEvent = new ManualResetEvent(false);
        private static X509Certificate2 _cert = X509Certificate2("..\\..\\cert.arm");

        static void Main(string[] args)
        {
            StartListening();
        }

        private static void StartListening()
        {
            IPEndPoint localEndPoint = new IPEndPoint(IPAddress.Any, 9002);

            if (localEndPoint != null)
            {
                Socket listener = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

                if (listener != null)
                {
                    listener.Bind(localEndPoint);
                    listener.Listen(10);

                    Console.WriteLine("Socket listener is running...");

                    listener.BeginAccept(new AsyncCallback(AcceptCallback), listener);
                }
            }
        }

        private static void AcceptCallback(IAsyncResult ar)
        {
            _manualResetEvent.Set();

            Socket listener = (Socket)ar.AsyncState;

            Socket handler = listener.EndAccept(ar);

            SslStream sslStream = new SslStream(new NetworkStream(handler, false));
            sslStream.AuthenticateAsServer(_cert); // I get exception on this line

            StateObject state = new StateObject();
            state.workSocket = handler;

            handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReceiveCallback), state);

            listener.BeginAccept(new AsyncCallback(AcceptCallback), listener);
        }

        private static void ReceiveCallback(IAsyncResult result)
        {
            StateObject state = (StateObject)result.AsyncState;
            Socket handler = state.workSocket;

            int numBytesReceived = handler.EndReceive(result);

            if (!handler.Connected)
            {
                handler.Close();
                return;
            }

            if (numBytesReceived > 0)
            {
                state.sb.Append(Encoding.ASCII.GetString(state.buffer, 0, numBytesReceived));

                string[] lines = state.sb.ToString().Split('\n');

                if (lines[lines.Length - 1] == "EOF")
                {
                    // All Data Received. Do Something.
                }
                else
                {
                    // All Data is not received. Continue reading...
                    handler.BeginReceive(state.buffer, 0, state.buffer.Length, SocketFlags.None, new AsyncCallback(ReceiveCallback), state);
                }
            }
        }
    }
}

Certification file is created successfully. I can see the data in _cert variable. It is OK.

The problem is that when I call the AuthenticateAsServer method I get NotSupportedException which says: "The server mode SSL must use a certificate with the associated private key".

How can I apply this certification file to my socket?

Is your service reachable over the open Internet? Do your clients access it by DNS name or IP address? If by DNS name, do you own or adminster the domain? — Jeffrey Hantin, Apr 27 '15 at 22:28

score 2 · Answer 1 · edited May 23 '17 at 12:10

2

You should probably use X509Certificate2 instead of X509Certificate. It could be the only step required to resolve this error.

X509Certificate2 has a member for the private key, unlike X509Certificate, and the SSL socket needs the private key to do its job.

edited May 23 '17 at 12:10

Community

1
1

answered Apr 26 '15 at 13:46

Roman Starkov

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It seems right. I'm searching for using private key now. – Orkun Bekar Apr 26 '15 at 14:24
cert file which is created by X509Certificate2 has no private key. Probably the problem is that. – Orkun Bekar Apr 26 '15 at 15:23
@OrkunBekar Yes, sounds like it. You can check by looking inside it: [here](http://stackoverflow.com/q/7400500/33080) is what it would look like if the file actually has the private key in it. It might not. Note that [.arm is the same as .pem](http://serverfault.com/a/312358/14642) (though I doubt renaming the file will make any difference in your case). – Roman Starkov Apr 26 '15 at 16:30
Yes, I renamed it and it still works but it does not have private key. – Orkun Bekar Apr 26 '15 at 16:59

How to Create SslStream for a non-blocking async socket

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