The service exposes a single endpoint for communicating that is programmatically created using the BindingHelper and EchoServiceHost classes. The endpoint consists of an address, a binding, and a contract. The binding is configured with a custom binding using SymmetricSecurityBindingElement and HttpTransportBindingElement. This sample sets the SymmetricSecurityBindingElement to use a service X.509 certificate to protect the symmetric key during transmission and to pass a UserNameToken along with the supporting X509SecurityToken in a WS-Security message header. The symmetric key is used to encrypt the message body and the username security token. The supporting token is passed as an additional binary security token in the WS-Security message header. The authenticity of the supporting token is proved by signing part of the message with the private key associated with the supporting X.509 security token.
public static Binding CreateMultiFactorAuthenticationBinding()
{
HttpTransportBindingElement httpTransport = new HttpTransportBindingElement();
// the message security binding element will be configured to require 2 tokens:
// 1) A username-password encrypted with the service token
// 2) A client certificate used to sign the message
// Instantiate a binding element that will require the username/password token in the message (encrypted with the server cert)
SymmetricSecurityBindingElement messageSecurity = SecurityBindingElement.CreateUserNameForCertificateBindingElement();
// Create supporting token parameters for the client X509 certificate.
X509SecurityTokenParameters clientX509SupportingTokenParameters = new X509SecurityTokenParameters();
// Specify that the supporting token is passed in message send by the client to the service
clientX509SupportingTokenParameters.InclusionMode = SecurityTokenInclusionMode.AlwaysToRecipient;
// Turn off derived keys
clientX509SupportingTokenParameters.RequireDerivedKeys = false;
// Augment the binding element to require the client's X509 certificate as an endorsing token in the message
messageSecurity.EndpointSupportingTokenParameters.Endorsing.Add(clientX509SupportingTokenParameters);
// Create a CustomBinding based on the constructed security binding element.
return new CustomBinding(messageSecurity, httpTransport);
}
The behavior specifies the service credentials that are to be used for client authentication and also information about the service X.509 certificate. The sample uses CN=localhost as a subject name in the service X.509 certificate.
override protected void InitializeRuntime()
{
// Extract the ServiceCredentials behavior or create one.
ServiceCredentials serviceCredentials =
this.Description.Behaviors.Find<ServiceCredentials>();
if (serviceCredentials == null)
{
serviceCredentials = new ServiceCredentials();
this.Description.Behaviors.Add(serviceCredentials);
}
// Set the service certificate
serviceCredentials.ServiceCertificate.SetCertificate(
"CN=localhost");
/*
Setting the CertificateValidationMode to PeerOrChainTrust means that if the certificate is in the Trusted People store, then it will be trusted without performing a validation of the certificate's issuer chain. This setting is used here for convenience so that the sample can be run without having to have certificates issued by a certificate authority (CA).
This setting is less secure than the default, ChainTrust. The security implications of this setting should be carefully considered before using PeerOrChainTrust in production code.
*/
serviceCredentials.ClientCertificate.Authentication.CertificateValidationMode = X509CertificateValidationMode.PeerOrChainTrust;
// Create the custom binding and add an endpoint to the service.
Binding multipleTokensBinding =
BindingHelper.CreateMultiFactorAuthenticationBinding();
this.AddServiceEndpoint(typeof(IEchoService),
multipleTokensBinding, string.Empty);
base.InitializeRuntime();
}[ServiceBehavior(IncludeExceptionDetailInFaults = true)]
public class EchoService : IEchoService
{
public string Echo()
{
string userName;
string certificateSubjectName;
GetCallerIdentities(
OperationContext.Current.ServiceSecurityContext,
out userName,
out certificateSubjectName);
return String.Format("Hello {0}, {1}",
userName, certificateSubjectName);
}
public void Dispose()
{
}
bool TryGetClaimValue<TClaimResource>(ClaimSet claimSet,
string claimType, out TClaimResource resourceValue)
where TClaimResource : class
{
resourceValue = default(TClaimResource);
IEnumerable<Claim> matchingClaims =
claimSet.FindClaims(claimType, Rights.PossessProperty);
if(matchingClaims == null)
return false;
IEnumerator<Claim> enumerator = matchingClaims.GetEnumerator();
if (enumerator.MoveNext())
{
resourceValue =
(enumerator.Current.Resource == null) ? null :
(enumerator.Current.Resource as TClaimResource);
return true;
}
else
{
return false;
}
}
// Returns the username and certificate subject name provided by
//the client
void GetCallerIdentities(ServiceSecurityContext
callerSecurityContext,
out string userName, out string certificateSubjectName)
{
userName = null;
certificateSubjectName = null;
// Look in all the claimsets in the authorization context
foreach (ClaimSet claimSet in
callerSecurityContext.AuthorizationContext.ClaimSets)
{
if (claimSet is WindowsClaimSet)
{
// Try to find a Name claim. This will have been
// generated from the windows username.
string tmpName;
if (TryGetClaimValue<string>(claimSet, ClaimTypes.Name,
out tmpName))
{
userName = tmpName;
}
}
else if (claimSet is X509CertificateClaimSet)
{
// Try to find an X500DisinguishedName claim. This will
// have been generated from the client certificate.
X500DistinguishedName tmpDistinguishedName;
if (TryGetClaimValue<X500DistinguishedName>(claimSet,
ClaimTypes.X500DistinguishedName,
out tmpDistinguishedName))
{
certificateSubjectName = tmpDistinguishedName.Name;
}
}
}
}
} The client endpoint is configured in a similar way to the service endpoint. The client uses the same BindingHelper class to create a binding. The rest of the setup is located in Client class. The client sets information about the user name security token, the supporting X.509 security token and information about the service X.509 certificate in the setup code to the client endpoint behaviors collection.
static void Main()
{
// Create the custom binding and an endpoint address for
// the service.
Binding multipleTokensBinding =
BindingHelper.CreateMultiFactorAuthenticationBinding();
EndpointAddress serviceAddress = new EndpointAddress(
"http://localhost/servicemodelsamples/service.svc");
ChannelFactory<IEchoService> channelFactory = null;
IEchoService client = null;
Console.WriteLine("Username authentication required.");
Console.WriteLine(
"Provide a valid machine or domain account. [domain\\user]");
Console.WriteLine(" Enter username:");
string username = Console.ReadLine();
Console.WriteLine(" Enter password:");
string password = "";
ConsoleKeyInfo info = Console.ReadKey(true);
while (info.Key != ConsoleKey.Enter)
{
if (info.Key != ConsoleKey.Backspace)
{
if (info.KeyChar != '\0')
{
password += info.KeyChar;
}
info = Console.ReadKey(true);
}
else if (info.Key == ConsoleKey.Backspace)
{
if (password != "")
{
password =
password.Substring(0, password.Length - 1);
}
info = Console.ReadKey(true);
}
}
for (int i = 0; i < password.Length; i++)
Console.Write("*");
Console.WriteLine();
try
{
// Create a proxy with the previously create binding and
// endpoint address
channelFactory =
new ChannelFactory<IEchoService>(
multipleTokensBinding, serviceAddress);
// configure the username credentials, the client
// certificate and the server certificate on the channel
// factory
channelFactory.Credentials.UserName.UserName = username;
channelFactory.Credentials.UserName.Password = password;
channelFactory.Credentials.ClientCertificate.SetCertificate(
"CN=client.com", StoreLocation.CurrentUser, StoreName.My);
channelFactory.Credentials.ServiceCertificate.SetDefaultCertificate(
"CN=localhost", StoreLocation.LocalMachine, StoreName.My);
client = channelFactory.CreateChannel();
Console.WriteLine("Echo service returned: {0}",
client.Echo());
((IChannel)client).Close();
channelFactory.Close();
}
catch (CommunicationException e)
{
Abort((IChannel)client, channelFactory);
// if there is a fault then print it out
FaultException fe = null;
Exception tmp = e;
while (tmp != null)
{
fe = tmp as FaultException;
if (fe != null)
{
break;
}
tmp = tmp.InnerException;
}
if (fe != null)
{
Console.WriteLine("The server sent back a fault: {0}",
fe.CreateMessageFault().Reason.GetMatchingTranslation().Text);
}
else
{
Console.WriteLine("The request failed with exception: {0}",e);
}
}
catch (TimeoutException)
{
Abort((IChannel)client, channelFactory);
Console.WriteLine("The request timed out");
}
catch (Exception e)
{
Abort((IChannel)client, channelFactory);
Console.WriteLine(
"The request failed with unexpected exception: {0}", e);
}
Console.WriteLine();
Console.WriteLine("Press <ENTER> to terminate client.");
Console.ReadLine();
}