Colm O hEigeartaigh

WS-Trust sample in Talend Service Factory 2.4.0

Colm O hEigeartaigh - Wed, 05/11/2011 - 18:18
In this post I will walk through the WS-Trust sample that ships with Talend Service Factory 2.4.0.

1) Download the artifacts

Go here and download Talend Service Factory 2.4.0. When this is done, go here and download the Talend Service Factory 2.4.0 examples (registration required). Extract the examples into the Talend Service Factory (TSF) install directory ($TSF_HOME).

2) Build and run the sample

Go to $TSF_HOME/examples/jaxws-ws-trust and start with the README.txt. Run "mvn eclipse:eclipse" to generate eclipse projects, and "mvn install" to build and install the various modules.

Both the CXF service provider and Metro STS used in this sample are deployed in Tomcat. To see how to configure Maven to install/uninstall these artifacts in Tomcat follow the instructions here. Finally, you need to make sure that the path to the keystores is correct for the Metro STS - follow the instructions in the README.txt for this.

Start Tomcat, and from the sts-war folder run "mvn install tomcat:deploy". Run the same command from the service-war folder to deploy the CXF service provider in Tomcat.

Finally to run the test, go to the client folder and run "mvn install exec:exec". You also have the option of running the client in Karaf (follow the instructions in the README.txt).

3) The sample

Three service invocations take place as part of this sample. For simplicity, I'll just concentrate on the third one, which shows how a SAML2 Assertion is used in a WS-Trust scenario.

3.1) The Service Provider

We'll start with the Service Provider, as the client will use the security policies defined in the WSDL of the Service Provider to access the STS. The Service is spring-loaded via the following configuration:

<jaxws:endpoint id="doubleitsaml2"
         <entry key="ws-security.callback-handler" value="..."/>
         <entry key="" value="..."/>
         <entry key="" value="false"/>

Three properties are required for the endpoint. The CallbackHandler implementation is required to provider the password used to access the private key in the Keystore, which is in turn configured in the "" file. The "" configuration turns off Basic Security Profile 1.1 compliance enforcement. This is required as the Metro STS generates a non BSP-compliant SAML Assertion (try removing this line, redeploying the service provider in tomcat and see what happens when the test is re-run).

The WSDL (DoubleIt.wsdl) contains the security policies for the service provider. It requires that the input and output SOAP Body elements must be signed and encrypted, and that all of the addressing headers must be signed in both directions. It also contains the following policy snippet:

        <sp:IssuedToken sp:IncludeToken="...AlwaysToRecipient">

This SecurityPolicy snippet defines that the communication with the service provider is secured via the SymmetricBinding, i.e. that it is secured via a secret key. The ProtectionToken policy describes how the secret key in turn is conveyed to the service provider in a secure way. In this example, it defines an IssuedToken policy, which is always sent to the recipient (service provider). Once the client sees this policy, it will know that it must contact a Security Token Service (STS) via the WS-Trust protocol to obtain a (issued) token that will convey the symmetric key to the service provider.

The IssuedToken policy has a RequestSecurityTokenTemplate policy, which the client will copy verbatim when contacting the STS for a security token. It describes the token type that is required (a SAML2 Assertion), the KeyType conveyed in the Assertion (Symmetric Key), and the size of the symmetric key (256 bits). It also contains an Issuer policy which describes how the STS may be contacted via a wsa EndpointReferenceType.

3.2) The Security Token Service (STS)

The STS used in this sample is the Metro STS. The port is secured with the following security policy binding:

         <sp:X509Token sp:IncludeToken=".../AlwaysToRecipient">
             <sp:WssX509V3Token10 />
         <sp:X509Token sp:IncludeToken=".../Never">
             <sp:WssX509V3Token10 />
             <sp:RequireIssuerSerialReference />

This Security Policy defines that the Asymmetric Binding is to be used in communication with the STS, i.e. that the client must sign the request using its private key, and include the corresponding X509 Certificate in the security header of the request, and encrypt the request using the public key of the STS. Authentication is performed on the basis of trust verification of the client's certificate, as the client illustrates proof-of-possession by signing some part of the request.

The WSDL of the STS also contains a "STSConfiguration" policy fragment, which defines that the issued key is encrypted, and lists the service provider endpoints, including the corresponding public keys.

3.3) The client

When the client wants to invoke on the service provider, it parses the security policy described above in the WSDL, and sees that it must first obtain an IssuedToken from a STS before it can construct the service request. The client is configured in spring as follows:

<jaxws:client name="{...}DoubleItPortSAML2" createdFromAPI="true">
    <entry key="ws-security.sts.client">
      <bean class="">
        <constructor-arg ref="cxf"/>
        <property name="wsdlLocation" value="DoubleItSTSService.wsdl"/>
        <property name="serviceName" value="{...}DoubleItSTSService"/>
        <property name="endpointName" value="{...}IDoubleItSTS..Port"/>
        <property name="properties">
            <entry key="ws-security.signature.username" value="..."/>
            <entry key="ws-security.callback-handler" value="..."/>
            <entry key="" value="..."/>
            <entry key="" value="..."/>
            <entry key="ws-security.encryption.username" value="..."/>

The STSClient bean contains the configuration required to contact the STS. The client parses the WSDL of the STS, and uses the supplied configuration parameters to construct a request that is secured by the Asymmetric Binding, as discussed above. This request is done via the WS-Trust protocol.

3.4) The STS request

In the SOAP Body of the request is the following information (decrypted):

    <wst:BinarySecret Type=".../Nonce">...</wst:BinarySecret>

The SecondaryParameters element is copied verbatim from the RequestSecurityTokenTemplate defined in the policy of the service provider. The RequestType element defines an "Issue" URI. AppliesTo refers to the address of the service provider. Entropy contains some client-generated entropy (which the STS will combine with its own Entropy to form a symmetric key), using the ComputedKeyAlgorithm URI.

3.5) The STS response

The response from the STS contains the following (decrypted) SOAP Body. It contains the token type of the requested token, the token itself, different ways of referring to the requested token, some entropy that the client can use to recreate the symmetric key, the lifetime of the requested token, etc:

      <trust:BinarySecret Type=".../Nonce">...</trust:BinarySecret>

The requested security token that is returned above is reproduced here. Note that the SubjectConfirmation Method is "holder-of-key", meaning that the client must illustrate proof of possession of the key contained in the EncryptedKey element of the Assertion. The EncryptedKey element is encrypted using the service provider's public key.

<saml2:Assertion ID="..." IssueInstant="..." Version="2.0">
    <saml2:NameID NameQualifier="...">...</saml2:NameID>
    <saml2:SubjectConfirmation Method="...:cm:holder-of-key">
 <saml2:Conditions NotBefore="..." NotOnOrAfter="..."></saml2:Conditions>

3.5) The Service Provider request

Once the client receives the Issued Token from the STS, it recreates the symmetric key needed to communicate with the service provider, by combining the entropy received from the STS with its own entropy to form the session key. The (decrypted) SAML2 Assertion is inserted into the security header "as is". The symmetric key is referenced in the request via the following structure:

<ds:KeyInfo Id="...">
  <wsse:SecurityTokenReference  wsse11:TokenType="...#SAMLV2.0" >
    <wsse:KeyIdentifier ValueType="...#SAMLID">...</wsse:KeyIdentifier>

The Service Provider verifies the signature of the STS on the SAML Assertion, and then decrypts the EncryptedKey fragment using its private key, to obtain the symmetric key used to decrypt/verify the client request. As the confirmation method is "holder-of-key", the Service Provider ensures that the same key was used to sign some portion of the request, thus proving that the client is in possession of the key.
Categories: Colm O hEigeartaigh

Talend Service Factory 2.4.0 released

Colm O hEigeartaigh - Fri, 04/29/2011 - 16:36
Talend Service Factory 2.4.0 has been released. It's based on Apache CXF 2.4.0, and so contains all of the security features in WSS4J 1.6.0, as well as the extensive support for SAML Assertions in CXF 2.4.0, that I have been blogging about for the last while.

In addition to this, some examples are available for download, which illustrate how to get these (security) features working in an OSGi container. A lot of work has gone into making sure that security libraries such as Apache Santuario, Apache WSS4J and Opensaml can be used in an OSGi environment, so I recommend checking the examples out to see how it can be done.

See Glen's blog for more information on the security examples. Also, see Sergey's blog for a discussion on some other examples based around transforming XML.
Categories: Colm O hEigeartaigh

SAML support in CXF 2.4.0

Colm O hEigeartaigh - Thu, 04/21/2011 - 13:28
The recent Apache CXF 2.4.0 release contains support for creating, securing, processing and validating SAML Assertions according to the WS-Security 1.1 SAML Token Profile. As there is no documentation available as yet on this new feature, in this blog post I will go through a SAML system test in CXF 2.4.0 in detail.

1) Running the Test

To run the SAML system test you can do the following:

svn co ws-security
mvn compile mvn test -Dtest=SamlTokenTest
2) The Client

2.1) The Client code

You can view the source of the tests here. There are a number of tests involving creating SAML 1.1 and 2.0 assertions, and sending them to a service provider over various security bindings (Transport/Symmetric/Asymmetric). To simplify things, we will focus on the fourth test named "testSaml2OverAsymmetric". Minus some negative tests, the basic test client invocation code is as simple as:

SpringBusFactory bf = new SpringBusFactory();URL busFile = SamlTokenTest.class.getResource("client/client.xml");Bus bus = bf.createBus(busFile.toString());SpringBusFactory.setDefaultBus(bus);SpringBusFactory.setThreadDefaultBus(bus);
DoubleItService service = new DoubleItService();DoubleItPortType saml2Port = service.getDoubleItSaml2AsymmetricPort();((BindingProvider)saml2Port).getRequestContext().put("ws-security.saml-callback-handler", new SamlCallbackHandler());BigInteger result = saml2Port.doubleIt(BigInteger.valueOf(25));assert result.equals(BigInteger.valueOf(50));
2.2) The WSDL

The service is described in the WSDL here. Take a look at the WS-SecurityPolicy called "DoubleItSaml2AsymmetricPolicy", which defines the security requirements for the "DoubleItSaml2AsymmetricPort". It defines an Asymmetric Binding, where the InitiatorToken (which defines the credential used to sign the request) is always sent to the recipient, and the RecipientToken (which defines the credential used to encrypt the request) is never sent to the recipient. Both Initiator and Recipient tokens are defined as X509 tokens. The input and output policies in the WSDL enforce that the SOAP Body must be signed using the Initiator credential, and encrypted using the Recipient credential.

In addition to specifying an asymmetric binding, the policy also defines a SignedSupportingToken, which contains a SAML (2.0) Token which is always sent to the recipient. In order to successfully invoke on the service, the client must include a SAML 2.0 token in the security header of the request. This policy looks like:

        <sp:SamlToken sp:IncludeToken="...AlwaysToRecipient">
2.3) The Client configuration

The client.xml referenced in the code block above contains a jaxws:client configuration for the DoubleItSaml2AsymmetricPort. It sets the following relevant jaxws:properties:
  1. - The Crypto properties file which describes where to find the service provider's public key.
  2. ws-security.encryption.username -  The alias to use to obtain the service provider's public key from the keystore reference in the Crypto properties file above.
  3. ws-security.callback-handler - A CallbackHandler object which is expected to supply the password used to access the private key for signature creation, or decryption.
  4. - The Crypto properties file which describes where to find the client's public/private key.
  5. ws-security.signature.username - The alias to use to obtain the client's private key from the keystore reference in the Crypto properties file above.
2.3) Creating a SAML token

CXF 2.4.0 defines a new jaxws:property ("ws-security-saml-callback-handler") which specifies a CallbackHandler instance used to create SAML Assertions. This object is added to the outbound request context above dynamically, however it could also have been configured in the spring bean along with the other ws-security parameters. The CallbackHandler object used in this test can be seen here. The CallbackHandler implementation is expected to obtain a SAMLCallback object, and to set the appropriate values on this object, e.g. SAML version, Subject, issuer, Authentication/Authorization/Attribute Statements, etc. In the example provided in this test, it creates a SAML 2.0 assertion (by default), sets a mock issuer, subject and attribute statement, and sets a subject confirmation method of sender-vouches. Some code in WSS4J then constructs a SAML Assertion by processing this SAMLCallback object. It's easy to construct a SAML Assertion in this way, as the following (edited) code shows:

SAMLCallback callback = (SAMLCallback) callbacks[i];callback.setSamlVersion(SAMLVersion.VERSION_20);callback.setIssuer("sts");String subjectName = "uid=sts-client,";String subjectQualifier = "";
SubjectBean subjectBean = new SubjectBean(subjectName, subjectQualifier, SAML2Constants.CONF_SENDER_VOUCHES);callback.setSubject(subjectBean);
AttributeStatementBean attrBean = new AttributeStatementBean();attrBean.setSubject(subjectBean);AttributeBean attributeBean = new AttributeBean();attributeBean.setSimpleName("subject-role");attributeBean.setAttributeValues(Collections.singletonList("system-user"));attrBean.setSamlAttributes(Collections.singletonList(attributeBean));callback.setAttributeStatementData(Collections.singletonList(attrBean));
2.4) The service request

The service request has a security header that contains the following elements:
  1. A BinarySecurityToken which consists of the X509Certificate of the client.
  2. A Timestamp.
  3. An EncryptedKey which consists of a symmetric key encrypted with the public key of the service provider, which is used to encrypt the SOAP Body.
  4. A SAML2 Assertion.
  5. A SecurityTokenReference to the SAML Assertion.
  6. A signature which signs the Timestamp, the SAML Assertion (via the SecurityTokenReference) and the (decrypted) SOAP body. The signing credential is the BinarySecurityToken element described above.
The SAML 2.0 assertion looks like (edited):

<saml2:Assertion ... Version="2.0">    <saml2:Issuer>sts</saml2:Issuer>    <saml2:Subject>      <saml2:NameID ...>uid=sts-client,</saml2:NameID>     <saml2:SubjectConfirmation Method="...:sender-vouches">     </saml2:SubjectConfirmation>   </saml2:Subject>   <saml2:Conditions NotBefore="..." NotOnOrAfter="..."/>    <saml2:AttributeStatement>     <saml2:Attribute FriendlyName="subject-role" ...>        <saml2:AttributeValue...>system-user</saml2:AttributeValue>     </saml2:Attribute>   </saml2:AttributeStatement></saml2:Assertion>
One thing to note is that as the SAML Assertion has a subject confirmation method of "sender-vouches", the client will automatically add the quality-of-service requirement that the signature which covers the SOAP Body will also cover the SAML Assertion.

3) The Server

3.1) The Server code

The SEI implementation is here, and the Server code itself is here.  The configuration is entirely driven through the WSDL and spring configuration, and so the code is as trivial as (edited):

URL busFile = Server.class.getResource("server.xml");
Bus busLocal = new SpringBusFactory().createBus(busFile);
new Server();

3.2) The Server configuration

The server.xml configuration file referenced above can be seen here. The jaxws:Endpoint configuration for this port should be self-explanatory (edited):

           <entry key="ws-security.username" value="bob"/>
           <entry key="ws-security.callback-handler"
           <entry key=""
           <entry key=""
           <entry key="ws-security.encryption.username" value="alice"/>

The server will process the request as per the security policy in the WSDL, checking that there is a signature in the security header, that covers the SOAP Body and SAML Assertion, that the SOAP Body is Encrypted, that a Timestamp is present and valid, and that the SAML Assertion is present, and is the correct version, etc. Authentication is done on the basis of trust verification of the client's X509Certificate, which was used to verify the signature element.

The SAML Assertion is ignored beyond this point for this system test. It is saved in the security processing results, so that a custom interceptor can do some additional validation or processing on it. In a future blog post, I will describe how to validate the Assertion that has been received in some custom manner.
Categories: Colm O hEigeartaigh

CXF 2.4.0 released

Colm O hEigeartaigh - Wed, 04/20/2011 - 16:27
Apache CXF 2.4.0 has been released. CXF 2.4.0 contains a number of new and improved features in the security space. From the release statement:
WS-Security improvements including support for SAML2 tokens, improved
validation of security tokens, better performance, increased WS-I Basic
Security Profile compliance, and much more.If those new features seem familiar, it's because most of the new functionality is driven by WSS4J 1.6.0, which I've blogged extensively about over the last few months. Probably the most significant new security functionality in CXF 2.4.0 is greatly enhanced support for SAML Assertions. CXF 2.4.0 supports the ability to create, secure, process and validate SAML Assertions in accordance with the WS-Security 1.1 SAML Token Profile. I intend to blog in more detail how to use these new features in CXF 2.4.0 over the next while.

See Dan Kulp's blog for more in-depth thoughts on the new release.
Categories: Colm O hEigeartaigh

WSS4J 1.6.0 released

Colm O hEigeartaigh - Fri, 04/15/2011 - 13:28
WSS4J 1.6.0 has been released:
The Apache Web Services team is pleased to announce the release of WSS4J 1.6.0. WSS4J 1.6.0 features support for SAML2 assertions, JSR-105 support, better spec compliance, performance work, support for trust-stores and a lot more besides. It is not API-compatible with the 1.5.x series of releases. For more information on the new features and changes in WSS4J 1.6.0 go to: To download WSS4J 1.6.0 go to: The Apache Web Services Team
Categories: Colm O hEigeartaigh

[WSS4J 1.6] Introducing Validators

Colm O hEigeartaigh - Tue, 04/05/2011 - 14:18
WSS4J 1.6 introduces the concept of a Validator, for validating credentials that have been processed by a Processor instance. This task was covered by the JIRA WSS-266.

An inbound security header is processed by WSS4J by iterating through each child element of the header, and by calling the appropriate Processor implementation to deal with each element. In WSS4J 1.5.x, some processors perform validation on the received token (e.g. UsernameTokens), whereas others store the processing results for later verification by third-party WS-Handler implementations (e.g. Timestamp verification, Certificate trust verification). There are some problems with this approach:
  • It is not consistent, some processors perform validation, others do not.
  • There is a potential security hole, in that it is assumed third-party code will know to validate the credentials that the WSS4J processors do not validate.
  • WSS4J will continue to process the rest of the security header even if the Timestamp is invalid, or the certificate non-trusted, which could lead to denial-of-service attacks.
  • There is no separation of concerns between processing the token and validating the token. If you want to change how the token is validated, you must replace the processor instance.
WSS4J 1.6 has moved Timestamp verification and certificate trust validation back into the processing of the security header, thus solving the first three points above. The fourth point is met by the new concept of Validators, as well as some changes to the way Processors and CallbackHandler implementations are used in WSS4J 1.6.

In WSS4J 1.5.x, CallbackHandler implementations are used in different ways by different processors, sometimes they are expected to verify a password (as for processing UsernameTokens), and other times they are expected to supply a password (as for decryption). In WSS4J 1.6, CallbackHandler implementations are only expected to supply a password (if it exists) to the processors. The Processor implementations do not perform any validation of the security token, instead they package up the processed token, along with any (password) information extracted from the CallbackHandler, and hand it off to a Validator implementation for Validation.

The Processor implementations get the specific Validator implementation to use via the RequestData parameter, which in turn asks a WSSConfig object for the Validator implementation. If the Validator is null, then no Validation is performed on the received token. The Processor then stores the received token as normal. WSS4J 1.6 comes with several default Validators, which are:
  • NoOpValidator: Does no processing of the credential
  • TimestampValidator: Validates a Timestamp
  • UsernameTokenValidator: Validates a UsernameToken
  • SignatureTrustValidator: Verifies trust in a signature
  • SamlAssertionValidator: Checks some HOK requirements on a SAML Assertion, and verifies trust on the (enveloped) signature.
There are some additional WSSecurityEngineResult constants that pertain to the Validator implementations:
  • TAG_VALIDATED_TOKEN: Indicates that the token corresponding to this result has been validated by a Validator implementation. Some of the processors do not have a default Validator implementation.
  • TAG_TRANSFORMED_TOKEN: A Validator implementation may transform a credential (into a SAML Assertion) as a result of Validation. This tag holds a reference to an AssertionWrapper instance, that represents a transformed version of the validated credential.
To validate an inbound UsernameToken in some custom way, simply associate the NoOpValidator with the UsernameToken QName in the WSSConfig of the RequestData object used to supply context information to the processors. After WSS4J has finished processing the security header, then extract the WSSecurityEngineResult instance corresponding to the WSConstants.UT action, and perform some custom validation on the token.

An example of how to add a custom Validator implementation is the STSTokenValidator in CXF 2.4.0. The STSTokenValidator tries to validate a received SAML Assertion locally, and if that fails, it dispatches it to a Security Token Service (STS) via the WS-Trust interface for validation. It also supports validating a UsernameToken and BinarySecurityToken in the same manner. The SecurityConstants class defines some configuration tags for specifying a custom validator for inbound SAML1, SAML2, UsernameToken, BinarySecurityToken, Signature and Timestamps. The STSTokenValidator can be configured by associating it with the appropriate configuration tag.
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