/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF 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.apache.hadoop.gateway.provider.authn.jwt.filter;
import javax.security.auth.Subject;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.hadoop.gateway.services.GatewayServices;
import org.apache.hadoop.gateway.services.security.CryptoService;
import java.io.IOException;
import java.security.Principal;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.HashSet;
import java.util.Set;
public class JWTFederationFilter implements Filter {
private static final String BEARER = "Bearer ";
private static final String GATEWAY_SERVICES_ATTRIBUTE = "org.apache.hadoop.gateway.gateway.services";
private JWTAuthority authority = null;
@Override
public void init( FilterConfig filterConfig ) throws ServletException {
GatewayServices services = (GatewayServices) filterConfig.getServletContext().getAttribute(GATEWAY_SERVICES_ATTRIBUTE);
CryptoService crypto = (CryptoService) services.getService("CryptoService");
authority = new JWTAuthority(crypto);
}
public void destroy() {
}
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
String header = ((HttpServletRequest) request).getHeader("Authorization");
if (header != null && header.startsWith(BEARER)) {
// what follows the bearer designator should be the JWT token being used to request or as an access token
String wireToken = header.substring(BEARER.length());
JWTToken token = JWTToken.parseToken(wireToken);
boolean verified = authority.verifyToken(token);
if (verified) {
// TODO: validate expiration
// TODO: confirm that audience matches intended target
Subject subject = createSubjectFromToken(token);
continueWithEstablishedSecurityContext(subject, (HttpServletRequest)request, (HttpServletResponse)response, chain);
}
else {
((HttpServletResponse) response).sendError(HttpServletResponse.SC_UNAUTHORIZED);
return; //break filter chain
}
}
else {
// no token provided in header
// TODO: may have to check cookie and url as well before sending error
((HttpServletResponse) response).sendError(HttpServletResponse.SC_UNAUTHORIZED);
return; //break filter chain
}
}
private void continueWithEstablishedSecurityContext(Subject subject, final HttpServletRequest request, final HttpServletResponse response, final FilterChain chain) throws IOException, ServletException {
try {
Subject.doAs(
subject,
new PrivilegedExceptionAction<Object>() {
@Override
public Object run() throws Exception {
chain.doFilter(request, response);
return null;
}
}
);
}
catch (PrivilegedActionException e) {
Throwable t = e.getCause();
if (t instanceof IOException) {
throw (IOException) t;
}
else if (t instanceof ServletException) {
throw (ServletException) t;
}
else {
throw new ServletException(t);
}
}
}
private Subject createSubjectFromToken(JWTToken token) {
final String principal = token.getPrincipal();
HashSet emptySet = new HashSet();
Set<Principal> principals = new HashSet<Principal>();
Principal p = new Principal() {
@Override
public String getName() {
return principal;
}
};
principals.add(p);
// The newly constructed Sets check whether this Subject has been set read-only
// before permitting subsequent modifications. The newly created Sets also prevent
// illegal modifications by ensuring that callers have sufficient permissions.
//
// To modify the Principals Set, the caller must have AuthPermission("modifyPrincipals").
// To modify the public credential Set, the caller must have AuthPermission("modifyPublicCredentials").
// To modify the private credential Set, the caller must have AuthPermission("modifyPrivateCredentials").
javax.security.auth.Subject subject = new javax.security.auth.Subject(true, principals, emptySet, emptySet);
return subject;
}
}