/*
* Copyright (c) 2012, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
*
* WSO2 Inc. licenses this file to you under the Apache License,
* Version 2.0 (the "License"); you may not use this file except
* in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.wso2.carbon.identity.oauth2.token.handlers.grant.saml;
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.collections.CollectionUtils;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.joda.time.DateTime;
import org.opensaml.DefaultBootstrap;
import org.opensaml.saml2.core.Assertion;
import org.opensaml.saml2.core.Audience;
import org.opensaml.saml2.core.AudienceRestriction;
import org.opensaml.saml2.core.Conditions;
import org.opensaml.saml2.core.SubjectConfirmation;
import org.opensaml.security.SAMLSignatureProfileValidator;
import org.opensaml.xml.ConfigurationException;
import org.opensaml.xml.XMLObject;
import org.opensaml.xml.security.x509.X509Credential;
import org.opensaml.xml.signature.SignatureValidator;
import org.opensaml.xml.validation.ValidationException;
import org.wso2.carbon.base.MultitenantConstants;
import org.wso2.carbon.identity.application.common.model.FederatedAuthenticatorConfig;
import org.wso2.carbon.identity.application.common.model.IdentityProvider;
import org.wso2.carbon.identity.application.common.model.Property;
import org.wso2.carbon.identity.application.common.util.IdentityApplicationConstants;
import org.wso2.carbon.identity.application.common.util.IdentityApplicationManagementUtil;
import org.wso2.carbon.identity.base.IdentityConstants;
import org.wso2.carbon.identity.base.IdentityException;
import org.wso2.carbon.identity.core.util.IdentityUtil;
import org.wso2.carbon.identity.oauth.common.OAuthConstants;
import org.wso2.carbon.identity.oauth.config.OAuthServerConfiguration;
import org.wso2.carbon.identity.oauth2.IdentityOAuth2Exception;
import org.wso2.carbon.identity.oauth2.token.OAuthTokenReqMessageContext;
import org.wso2.carbon.identity.oauth2.token.handlers.grant.AbstractAuthorizationGrantHandler;
import org.wso2.carbon.identity.oauth2.util.OAuth2Util;
import org.wso2.carbon.identity.oauth2.util.X509CredentialImpl;
import org.wso2.carbon.idp.mgt.IdentityProviderManagementException;
import org.wso2.carbon.idp.mgt.IdentityProviderManager;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
/**
* This implements SAML 2.0 Bearer Assertion Profile for OAuth 2.0 -
* http://tools.ietf.org/html/draft-ietf-oauth-saml2-bearer-14.
*/
public class SAML2BearerGrantHandler extends AbstractAuthorizationGrantHandler {
private static Log log = LogFactory.getLog(SAML2BearerGrantHandler.class);
SAMLSignatureProfileValidator profileValidator = null;
@Override
public void init() throws IdentityOAuth2Exception {
super.init();
Thread thread = Thread.currentThread();
ClassLoader loader = thread.getContextClassLoader();
thread.setContextClassLoader(this.getClass().getClassLoader());
try {
DefaultBootstrap.bootstrap();
} catch (ConfigurationException e) {
log.error("Error in bootstrapping the OpenSAML2 library", e);
throw new IdentityOAuth2Exception("Error in bootstrapping the OpenSAML2 library");
} finally {
thread.setContextClassLoader(loader);
}
profileValidator = new SAMLSignatureProfileValidator();
}
/**
* We're validating the SAML token that we receive from the request. Through the assertion parameter is the POST
* request. A request format that we handle here looks like,
* <p/>
* POST /token.oauth2 HTTP/1.1
* Host: as.example.com
* Content-Type: application/x-www-form-urlencoded
* <p/>
* grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Asaml2-bearer&
* assertion=PHNhbWxwOl...[omitted for brevity]...ZT4
*
* @param tokReqMsgCtx Token message request context
* @return true if validation is successful, false otherwise
* @throws org.wso2.carbon.identity.oauth2.IdentityOAuth2Exception
*/
@Override
public boolean validateGrant(OAuthTokenReqMessageContext tokReqMsgCtx) throws IdentityOAuth2Exception {
if(!super.validateGrant(tokReqMsgCtx)){
return false;
}
Assertion assertion = null;
IdentityProvider identityProvider = null;
String tokenEndpointAlias = null;
String tenantDomain = tokReqMsgCtx.getOauth2AccessTokenReqDTO().getTenantDomain();
if (tenantDomain == null || "".equals(tenantDomain)) {
tenantDomain = MultitenantConstants.SUPER_TENANT_DOMAIN_NAME;
}
// Logging the SAML token
if (log.isDebugEnabled() && IdentityUtil.isTokenLoggable(IdentityConstants.IdentityTokens.SAML_ASSERTION)) {
log.debug("Received SAML assertion : " +
new String(Base64.decodeBase64(tokReqMsgCtx.getOauth2AccessTokenReqDTO().getAssertion()))
);
}
try {
XMLObject samlObject = IdentityUtil.unmarshall(new String(Base64.decodeBase64(
tokReqMsgCtx.getOauth2AccessTokenReqDTO().getAssertion())));
assertion = (Assertion) samlObject;
} catch (IdentityException e) {
// fault in the saml2 assertion
if(log.isDebugEnabled()){
log.debug("Error while unmashalling the assertion", e);
}
return false;
}
if (assertion == null) {
log.debug("Assertion is null, cannot continue");
return false;
}
/**
* The Assertion MUST contain a <Subject> element. The subject MAY identify the resource owner for whom
* the access token is being requested. For client authentication, the Subject MUST be the "client_id"
* of the OAuth client. When using an Assertion as an authorization grant, the Subject SHOULD identify
* an authorized accessor for whom the access token is being requested (typically the resource owner, or
* an authorized delegate). Additional information identifying the subject/principal of the transaction
* MAY be included in an <AttributeStatement>.
*/
if (assertion.getSubject() != null) {
String resourceOwnerUserName = assertion.getSubject().getNameID().getValue();
if (StringUtils.isBlank(resourceOwnerUserName)) {
if (log.isDebugEnabled()){
log.debug("NameID in Assertion cannot be empty");
}
return false;
}
tokReqMsgCtx.setAuthorizedUser(OAuth2Util.getUserFromUserName(resourceOwnerUserName));
} else {
if (log.isDebugEnabled()) {
log.debug("Cannot find a Subject in the Assertion");
}
return false;
}
if (assertion.getIssuer() == null || "".equals(assertion.getIssuer().getValue())) {
if (log.isDebugEnabled()) {
log.debug("Issuer is empty in the SAML assertion");
}
return false;
} else {
try {
identityProvider = IdentityProviderManager.getInstance().
getIdPByAuthenticatorPropertyValue("IdPEntityId",
assertion.getIssuer().getValue(), tenantDomain, false);
// IF Federated IDP not found get the resident IDP and check,
// resident IDP entitiID == issuer
if (identityProvider != null) {
if (IdentityApplicationConstants.RESIDENT_IDP_RESERVED_NAME.equals(
identityProvider.getIdentityProviderName())) {
identityProvider = IdentityProviderManager.getInstance().getResidentIdP(tenantDomain);
FederatedAuthenticatorConfig[] fedAuthnConfigs =
identityProvider.getFederatedAuthenticatorConfigs();
String idpEntityId = null;
// Get SAML authenticator
FederatedAuthenticatorConfig samlAuthenticatorConfig =
IdentityApplicationManagementUtil.getFederatedAuthenticator(fedAuthnConfigs,
IdentityApplicationConstants.Authenticator.SAML2SSO.NAME);
// Get Entity ID from SAML authenticator
Property samlProperty = IdentityApplicationManagementUtil.getProperty(
samlAuthenticatorConfig.getProperties(),
IdentityApplicationConstants.Authenticator.SAML2SSO.IDP_ENTITY_ID);
if (samlProperty != null) {
idpEntityId = samlProperty.getValue();
}
if (idpEntityId == null || !assertion.getIssuer().getValue().equals(idpEntityId)) {
if(log.isDebugEnabled()) {
log.debug("SAML Token Issuer verification failed against resident Identity Provider " +
"in tenant : " + tenantDomain + ". Received : " +
assertion.getIssuer().getValue() + ", Expected : " + idpEntityId);
}
return false;
}
// Get OpenIDConnect authenticator == OAuth
// authenticator
FederatedAuthenticatorConfig oauthAuthenticatorConfig =
IdentityApplicationManagementUtil.getFederatedAuthenticator(fedAuthnConfigs,
IdentityApplicationConstants.Authenticator.OIDC.NAME);
// Get OAuth token endpoint
Property oauthProperty = IdentityApplicationManagementUtil.getProperty(
oauthAuthenticatorConfig.getProperties(),
IdentityApplicationConstants.Authenticator.OIDC.OAUTH2_TOKEN_URL);
if (oauthProperty != null) {
tokenEndpointAlias = oauthProperty.getValue();
}
} else {
// Get Alias from Federated IDP
tokenEndpointAlias = identityProvider.getAlias();
}
} else {
if(log.isDebugEnabled()) {
log.debug("SAML Token Issuer : " + assertion.getIssuer().getValue() +
" not registered as a local Identity Provider in tenant : " + tenantDomain);
}
return false;
}
} catch (IdentityProviderManagementException e) {
log.error("Error while getting Federated Identity Provider ", e);
}
}
/**
* The Assertion MUST contain <Conditions> element with an <AudienceRestriction> element with an <Audience>
* element containing a URI reference that identifies the authorization server, or the service provider
* SAML entity of its controlling domain, as an intended audience. The token endpoint URL of the
* authorization server MAY be used as an acceptable value for an <Audience> element. The authorization
* server MUST verify that it is an intended audience for the Assertion.
*/
if (StringUtils.isBlank(tokenEndpointAlias)) {
if (log.isDebugEnabled()){
String errorMsg = "Token Endpoint alias has not been configured in the Identity Provider : "
+ identityProvider.getIdentityProviderName() + " in tenant : " + tenantDomain;
log.debug(errorMsg);
}
return false;
}
Conditions conditions = assertion.getConditions();
if (conditions != null) {
//Set validity period extracted from SAML Assertion
long curTimeInMillis = Calendar.getInstance().getTimeInMillis();
tokReqMsgCtx.setValidityPeriod(conditions.getNotOnOrAfter().getMillis() - curTimeInMillis);
List<AudienceRestriction> audienceRestrictions = conditions.getAudienceRestrictions();
if (audienceRestrictions != null && !audienceRestrictions.isEmpty()) {
boolean audienceFound = false;
for (AudienceRestriction audienceRestriction : audienceRestrictions) {
if (CollectionUtils.isNotEmpty(audienceRestriction.getAudiences())) {
for (Audience audience : audienceRestriction.getAudiences()) {
if (audience.getAudienceURI().equals(tokenEndpointAlias)) {
audienceFound = true;
break;
}
}
}
if (audienceFound) {
break;
}
}
if (!audienceFound) {
if (log.isDebugEnabled()) {
log.debug("SAML Assertion Audience Restriction validation failed against the Audience : " +
tokenEndpointAlias + " of Identity Provider : " +
identityProvider.getIdentityProviderName() + " in tenant : " + tenantDomain);
}
return false;
}
} else {
if (log.isDebugEnabled()) {
String message = "SAML Assertion doesn't contain AudienceRestrictions";
log.debug(message);
}
return false;
}
} else {
if (log.isDebugEnabled()) {
String message = "SAML Assertion doesn't contain Conditions";
log.debug(message);
}
return false;
}
/**
* The Assertion MUST have an expiry that limits the time window during which it can be used. The expiry
* can be expressed either as the NotOnOrAfter attribute of the <Conditions> element or as the NotOnOrAfter
* attribute of a suitable <SubjectConfirmationData> element.
*/
/**
* The <Subject> element MUST contain at least one <SubjectConfirmation> element that allows the
* authorization server to confirm it as a Bearer Assertion. Such a <SubjectConfirmation> element MUST
* have a Method attribute with a value of "urn:oasis:names:tc:SAML:2.0:cm:bearer". The
* <SubjectConfirmation> element MUST contain a <SubjectConfirmationData> element, unless the Assertion
* has a suitable NotOnOrAfter attribute on the <Conditions> element, in which case the
* <SubjectConfirmationData> element MAY be omitted. When present, the <SubjectConfirmationData> element
* MUST have a Recipient attribute with a value indicating the token endpoint URL of the authorization
* server (or an acceptable alias). The authorization server MUST verify that the value of the Recipient
* attribute matches the token endpoint URL (or an acceptable alias) to which the Assertion was delivered.
* The <SubjectConfirmationData> element MUST have a NotOnOrAfter attribute that limits the window during
* which the Assertion can be confirmed. The <SubjectConfirmationData> element MAY also contain an Address
* attribute limiting the client address from which the Assertion can be delivered. Verification of the
* Address is at the discretion of the authorization server.
*/
DateTime notOnOrAfterFromConditions = null;
Set<DateTime> notOnOrAfterFromSubjectConfirmations = new HashSet<DateTime>();
boolean bearerFound = false;
List<String> recipientURLS = new ArrayList<>();
if (assertion.getConditions() != null && assertion.getConditions().getNotOnOrAfter() != null) {
notOnOrAfterFromConditions = assertion.getConditions().getNotOnOrAfter();
}
List<SubjectConfirmation> subjectConfirmations = assertion.getSubject().getSubjectConfirmations();
if (subjectConfirmations != null && !subjectConfirmations.isEmpty()) {
for (SubjectConfirmation s : subjectConfirmations) {
if (s.getMethod() != null) {
if (s.getMethod().equals(OAuthConstants.OAUTH_SAML2_BEARER_METHOD)) {
bearerFound = true;
}
} else {
if (log.isDebugEnabled()){
log.debug("Cannot find Method attribute in SubjectConfirmation " + s.toString());
}
return false;
}
if (s.getSubjectConfirmationData() != null) {
if (s.getSubjectConfirmationData().getRecipient() != null) {
recipientURLS.add(s.getSubjectConfirmationData().getRecipient());
}
if (s.getSubjectConfirmationData().getNotOnOrAfter() != null) {
notOnOrAfterFromSubjectConfirmations.add(s.getSubjectConfirmationData().getNotOnOrAfter());
} else {
if (log.isDebugEnabled()){
log.debug("Cannot find NotOnOrAfter attribute in SubjectConfirmationData " +
s.getSubjectConfirmationData().toString());
}
return false;
}
} else if (s.getSubjectConfirmationData() == null && notOnOrAfterFromConditions == null) {
if (log.isDebugEnabled()){
log.debug("Neither can find NotOnOrAfter attribute in Conditions nor SubjectConfirmationData" +
"in SubjectConfirmation " + s.toString());
}
return false;
}
}
} else {
if (log.isDebugEnabled()){
log.debug("No SubjectConfirmation exist in Assertion");
}
return false;
}
if (!bearerFound) {
if (log.isDebugEnabled()){
log.debug("Failed to find a SubjectConfirmation with a Method attribute having : " +
OAuthConstants.OAUTH_SAML2_BEARER_METHOD);
}
return false;
}
if (CollectionUtils.isNotEmpty(recipientURLS) && !recipientURLS.contains(tokenEndpointAlias)) {
if (log.isDebugEnabled()){
log.debug("None of the recipient URLs match against the token endpoint alias : " + tokenEndpointAlias +
" of Identity Provider " + identityProvider.getIdentityProviderName() + " in tenant : " +
tenantDomain);
}
return false;
}
/**
* The authorization server MUST verify that the NotOnOrAfter instant has not passed, subject to allowable
* clock skew between systems. An invalid NotOnOrAfter instant on the <Conditions> element invalidates
* the entire Assertion. An invalid NotOnOrAfter instant on a <SubjectConfirmationData> element only
* invalidates the individual <SubjectConfirmation>. The authorization server MAY reject Assertions with
* a NotOnOrAfter instant that is unreasonably far in the future. The authorization server MAY ensure
* that Bearer Assertions are not replayed, by maintaining the set of used ID values for the length of
* time for which the Assertion would be considered valid based on the applicable NotOnOrAfter instant.
*/
if (notOnOrAfterFromConditions != null && notOnOrAfterFromConditions.compareTo(new DateTime()) < 1) {
// notOnOrAfter is an expired timestamp
if (log.isDebugEnabled()){
log.debug("NotOnOrAfter is having an expired timestamp in Conditions element");
}
return false;
}
boolean validSubjectConfirmationDataExists = false;
if (!notOnOrAfterFromSubjectConfirmations.isEmpty()) {
for (DateTime entry : notOnOrAfterFromSubjectConfirmations) {
if (entry.compareTo(new DateTime()) >= 1) {
validSubjectConfirmationDataExists = true;
}
}
}
if (notOnOrAfterFromConditions == null && !validSubjectConfirmationDataExists) {
if (log.isDebugEnabled()){
log.debug("No valid NotOnOrAfter element found in SubjectConfirmations");
}
return false;
}
/**
* The Assertion MUST be digitally signed by the issuer and the authorization server MUST verify the
* signature.
*/
try {
profileValidator.validate(assertion.getSignature());
} catch (ValidationException e) {
// Indicates signature did not conform to SAML Signature profile
log.error("Signature do not confirm to SAML signature profile.", e);
return false;
}
X509Certificate x509Certificate = null;
try {
x509Certificate = (X509Certificate) IdentityApplicationManagementUtil
.decodeCertificate(identityProvider.getCertificate());
} catch (CertificateException e) {
throw new IdentityOAuth2Exception("Error occurred while decoding public certificate of Identity Provider "
+ identityProvider.getIdentityProviderName() + " for tenant domain " + tenantDomain, e);
}
try {
X509Credential x509Credential = new X509CredentialImpl(x509Certificate);
SignatureValidator signatureValidator = new SignatureValidator(x509Credential);
signatureValidator.validate(assertion.getSignature());
if (log.isDebugEnabled()){
log.debug("Signature validation successful");
}
} catch (ValidationException e) {
log.error("Error while validating the signature.", e);
return false;
}
/**
* The authorization server MUST verify that the Assertion is valid in all other respects per
* [OASIS.saml-core-2.0-os], such as (but not limited to) evaluating all content within the Conditions
* element including the NotOnOrAfter and NotBefore attributes, rejecting unknown condition types, etc.
*
* [OASIS.saml-core-2.0-os] - http://docs.oasis-open.org/security/saml/v2.0/saml-core-2.0-os.pdf
*/
// TODO: Throw the SAML request through the general SAML2 validation routines
tokReqMsgCtx.setScope(tokReqMsgCtx.getOauth2AccessTokenReqDTO().getScope());
// Storing the Assertion. This will be used in OpenID Connect for example
tokReqMsgCtx.addProperty(OAuthConstants.OAUTH_SAML2_ASSERTION, assertion);
// Invoking extension
SAML2TokenCallbackHandler callback =
OAuthServerConfiguration.getInstance()
.getSAML2TokenCallbackHandler();
if (callback != null) {
if (log.isDebugEnabled()){
log.debug("Invoking the SAML2 Token callback handler ");
}
callback.handleSAML2Token(tokReqMsgCtx);
}
return true;
}
}