SSL client/server mutual authentication

Question

Hello I am trying to do in C# an ssl client/server communication with mutual authentication using server and client certificate. A managed to do the ssl communication only using server certificate, where on the client side I use sth like that:

TcpClient client = new TcpClient(machineName, port);
//Create an SSL stream that will close the client's stream.
   SslStream sslStream = new SslStream(
   client.GetStream(),
   false,
   new RemoteCertificateValidationCallback(ValidateServerCertificate),
   null
   );
try
{
    // The server name must match the name on the server certificate.
    sslStream.AuthenticateAsClient(serverName);
}
catch (AuthenticationException e)
{
    Console.WriteLine("Exception: {0}", e.Message);
    if (e.InnerException != null)
    {
        Console.WriteLine("Inner exception: {0}", e.InnerException.Message);
    }
    Console.WriteLine("Authentication failed - closing the connection.");
    client.Close();
    return;
} 

I assume I would need to use

AuthenticateAsClient(string targetHost, X509CertificateCollection clientCertificates, SslProtocols enabledSslProtocols, bool checkCertificateRevocation)

method, am I corrent? Could anyone please show me how to use it with all things around?Even on the server side, or point me to a basic example?

Thank you a lot.

Answer 1

static void HTTPSClient()
{
    try
    {
        string message = "GET / HTTP/1.0\r\nHost: host.com\r\n\r\n";

        byte[] data = System.Text.Encoding.ASCII.GetBytes(message);

        string server = "host.com";
        int nPort = 443;
        TcpClient client = new TcpClient(server, nPort);

        X509Certificate2Collection cCollection = new X509Certificate2Collection();
        cCollection.Add(new X509Certificate2("cert.pfx", "password"));


        using (SslStream sslStream = new SslStream(client.GetStream(), false, new RemoteCertificateValidationCallback(ValidateServerCertificate), null))
        {
            // Add a client certificate to the ssl connection
            sslStream.AuthenticateAsClient(server, cCollection, System.Security.Authentication.SslProtocols.Default, true);

            sslStream.Write(data, 0, data.Length);

            data = new Byte[8192];
            int bytes = 0;
            string responseData = "";

            do
            {
                bytes = sslStream.Read(data, 0, data.Length);
                if (bytes > 0)
                {
                    responseData += System.Text.Encoding.ASCII.GetString(data, 0, bytes);
                }
            }
            while (bytes > 0);

            Console.WriteLine("Response: " + responseData);
        }

        // Disconnect and close the client
        client.Close();
    }
    catch (Exception ex)
    {
        Console.WriteLine("Error: " + ex.ToString());
    }
}

public static bool ValidateServerCertificate(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
{
    if (sslPolicyErrors == SslPolicyErrors.None)
        return true;

    Console.WriteLine("Certificate error: {0}", sslPolicyErrors);

    // Do not allow this client to communicate with unauthenticated servers.
    return false;
}

Answer 2

1. You need a x509 self certificate, to create it simple, download pluralsight self cert
2. Generate certificate as in image
3. Create new web site, there choose wcf service.
4. Add in solution new console application, to test our service.

5. In web.config of service put configuration:

    <?xml version="1.0"?> <configuration> <system.serviceModel> <behaviors> <serviceBehaviors> <behavior name="ServiceCredentialsBehavior"> <serviceCredentials> <serviceCertificate findValue="cn=cool" storeName="TrustedPeople" storeLocation="CurrentUser" /> </serviceCredentials> <serviceMetadata httpGetEnabled="true" /> </behavior> </serviceBehaviors> </behaviors> <services> <service behaviorConfiguration="ServiceCredentialsBehavior" name="Service"> <endpoint address="" binding="wsHttpBinding" bindingConfiguration="MessageAndUserName" name="SecuredByTransportEndpoint" contract="IService"/> </service> </services> <bindings> <wsHttpBinding> <binding name="MessageAndUserName"> <security mode="Message"> <message clientCredentialType="UserName"/> </security> </binding> </wsHttpBinding> </bindings> <client/>

6. In Service class, delete existing methods and add:

   public string TestAccess() { return OperationContext.Current.ServiceSecurityContext.PrimaryIdentity.Name; }

7. in IService delete Data Contract, delete operation contracts and add new operation contract:

   [OperationContract]
   public string TestAccess();

8. Run service and add service reference in client application to our service

9. Client config:

    <?xml version="1.0" encoding="utf-8"?> <configuration> <system.serviceModel> <behaviors> <endpointBehaviors> <behavior name="LocalCertValidation"> <clientCredentials> <serviceCertificate> <authentication certificateValidationMode="PeerTrust" trustedStoreLocation="CurrentUser" /> </serviceCertificate> </clientCredentials> </behavior> </endpointBehaviors> </behaviors> <bindings> <wsHttpBinding> <binding name="WSHttpBinding_IService" > <security mode="Message"> <message clientCredentialType="UserName" /> </security> </binding> </wsHttpBinding> </bindings> <client> <endpoint address="your service addresss" binding="wsHttpBinding" bindingConfiguration="WSHttpBinding_IService" contract="ServiceReference1.IService" name="WSHttpBinding_IService" behaviorConfiguration="LocalCertValidation"> <identity> <dns value ="cool" /> </identity> </endpoint> </client>

10. Client code:

    ServiceClient client = new ServiceClient();
    client.ClientCredentials.UserName.UserName = "Your windows user";
    client.ClientCredentials.UserName.Password = "Your windows user password";
    Console.WriteLine(client.TestAccess());
    Console.ReadLine();
    

11. if you dont want to use windows login/password you have to create a custom user/passwd validator ->msdn :
    Regards,
    
    Sergiu.