/**
* Licensed 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. See accompanying LICENSE file.
*/
package org.apache.hadoop.security.authentication.server;
import org.apache.hadoop.security.authentication.client.AuthenticatedURL;
import org.apache.hadoop.security.authentication.client.AuthenticationException;
import org.apache.hadoop.security.authentication.util.Signer;
import org.apache.hadoop.security.authentication.util.SignerException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
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.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.security.Principal;
import java.util.Enumeration;
import java.util.Properties;
import java.util.Random;
/**
* The {@link AuthenticationFilter} enables protecting web application resources with different (pluggable)
* authentication mechanisms.
* <p/>
* Out of the box it provides 2 authentication mechanisms: Pseudo and Kerberos SPNEGO.
* <p/>
* Additional authentication mechanisms are supported via the {@link AuthenticationHandler} interface.
* <p/>
* This filter delegates to the configured authentication handler for authentication and once it obtains an
* {@link AuthenticationToken} from it, sets a signed HTTP cookie with the token. For client requests
* that provide the signed HTTP cookie, it verifies the validity of the cookie, extracts the user information
* and lets the request proceed to the target resource.
* <p/>
* The supported configuration properties are:
* <ul>
* <li>config.prefix: indicates the prefix to be used by all other configuration properties, the default value
* is no prefix. See below for details on how/why this prefix is used.</li>
* <li>[#PREFIX#.]type: simple|kerberos|#CLASS#, 'simple' is short for the
* {@link PseudoAuthenticationHandler}, 'kerberos' is short for {@link KerberosAuthenticationHandler}, otherwise
* the full class name of the {@link AuthenticationHandler} must be specified.</li>
* <li>[#PREFIX#.]signature.secret: the secret used to sign the HTTP cookie value. The default value is a random
* value. Unless multiple webapp instances need to share the secret the random value is adequate.</li>
* <li>[#PREFIX#.]token.validity: time -in seconds- that the generated token is valid before a
* new authentication is triggered, default value is <code>3600</code> seconds.</li>
* <li>[#PREFIX#.]cookie.domain: domain to use for the HTTP cookie that stores the authentication token.</li>
* <li>[#PREFIX#.]cookie.path: path to use for the HTTP cookie that stores the authentication token.</li>
* </ul>
* <p/>
* The rest of the configuration properties are specific to the {@link AuthenticationHandler} implementation and the
* {@link AuthenticationFilter} will take all the properties that start with the prefix #PREFIX#, it will remove
* the prefix from it and it will pass them to the the authentication handler for initialization. Properties that do
* not start with the prefix will not be passed to the authentication handler initialization.
*/
public class AuthenticationFilter implements Filter {
private static Logger LOG = LoggerFactory.getLogger(AuthenticationFilter.class);
/**
* Constant for the property that specifies the configuration prefix.
*/
public static final String CONFIG_PREFIX = "config.prefix";
/**
* Constant for the property that specifies the authentication handler to use.
*/
public static final String AUTH_TYPE = "type";
/**
* Constant for the property that specifies the secret to use for signing the HTTP Cookies.
*/
public static final String SIGNATURE_SECRET = "signature.secret";
/**
* Constant for the configuration property that indicates the validity of the generated token.
*/
public static final String AUTH_TOKEN_VALIDITY = "token.validity";
/**
* Constant for the configuration property that indicates the domain to use in the HTTP cookie.
*/
public static final String COOKIE_DOMAIN = "cookie.domain";
/**
* Constant for the configuration property that indicates the path to use in the HTTP cookie.
*/
public static final String COOKIE_PATH = "cookie.path";
private static final Random RAN = new Random();
private Signer signer;
private AuthenticationHandler authHandler;
private boolean randomSecret;
private long validity;
private String cookieDomain;
private String cookiePath;
/**
* Initializes the authentication filter.
* <p/>
* It instantiates and initializes the specified {@link AuthenticationHandler}.
* <p/>
*
* @param filterConfig filter configuration.
*
* @throws ServletException thrown if the filter or the authentication handler could not be initialized properly.
*/
@Override
public void init(FilterConfig filterConfig) throws ServletException {
String configPrefix = filterConfig.getInitParameter(CONFIG_PREFIX);
configPrefix = (configPrefix != null) ? configPrefix + "." : "";
Properties config = getConfiguration(configPrefix, filterConfig);
String authHandlerName = config.getProperty(AUTH_TYPE, null);
String authHandlerClassName;
if (authHandlerName == null) {
throw new ServletException("Authentication type must be specified: simple|kerberos|<class>");
}
if (authHandlerName.equals("simple")) {
authHandlerClassName = PseudoAuthenticationHandler.class.getName();
} else if (authHandlerName.equals("kerberos")) {
authHandlerClassName = KerberosAuthenticationHandler.class.getName();
} else {
authHandlerClassName = authHandlerName;
}
try {
Class<?> klass = Thread.currentThread().getContextClassLoader().loadClass(authHandlerClassName);
authHandler = (AuthenticationHandler) klass.newInstance();
authHandler.init(config);
} catch (ClassNotFoundException ex) {
throw new ServletException(ex);
} catch (InstantiationException ex) {
throw new ServletException(ex);
} catch (IllegalAccessException ex) {
throw new ServletException(ex);
}
String signatureSecret = config.getProperty(configPrefix + SIGNATURE_SECRET);
if (signatureSecret == null) {
signatureSecret = Long.toString(RAN.nextLong());
randomSecret = true;
LOG.warn("'signature.secret' configuration not set, using a random value as secret");
}
signer = new Signer(signatureSecret.getBytes());
validity = Long.parseLong(config.getProperty(AUTH_TOKEN_VALIDITY, "36000")) * 1000; //10 hours
cookieDomain = config.getProperty(COOKIE_DOMAIN, null);
cookiePath = config.getProperty(COOKIE_PATH, null);
}
/**
* Returns the authentication handler being used.
*
* @return the authentication handler being used.
*/
protected AuthenticationHandler getAuthenticationHandler() {
return authHandler;
}
/**
* Returns if a random secret is being used.
*
* @return if a random secret is being used.
*/
protected boolean isRandomSecret() {
return randomSecret;
}
/**
* Returns the validity time of the generated tokens.
*
* @return the validity time of the generated tokens, in seconds.
*/
protected long getValidity() {
return validity / 1000;
}
/**
* Returns the cookie domain to use for the HTTP cookie.
*
* @return the cookie domain to use for the HTTP cookie.
*/
protected String getCookieDomain() {
return cookieDomain;
}
/**
* Returns the cookie path to use for the HTTP cookie.
*
* @return the cookie path to use for the HTTP cookie.
*/
protected String getCookiePath() {
return cookiePath;
}
/**
* Destroys the filter.
* <p/>
* It invokes the {@link AuthenticationHandler#destroy()} method to release any resources it may hold.
*/
@Override
public void destroy() {
if (authHandler != null) {
authHandler.destroy();
authHandler = null;
}
}
/**
* Returns the filtered configuration (only properties starting with the specified prefix). The property keys
* are also trimmed from the prefix. The returned {@link Properties} object is used to initialized the
* {@link AuthenticationHandler}.
* <p/>
* This method can be overriden by subclasses to obtain the configuration from other configuration source than
* the web.xml file.
*
* @param configPrefix configuration prefix to use for extracting configuration properties.
* @param filterConfig filter configuration object
*
* @return the configuration to be used with the {@link AuthenticationHandler} instance.
*
* @throws ServletException thrown if the configuration could not be created.
*/
protected Properties getConfiguration(String configPrefix, FilterConfig filterConfig) throws ServletException {
Properties props = new Properties();
Enumeration<?> names = filterConfig.getInitParameterNames();
while (names.hasMoreElements()) {
String name = (String) names.nextElement();
if (name.startsWith(configPrefix)) {
String value = filterConfig.getInitParameter(name);
props.put(name.substring(configPrefix.length()), value);
}
}
return props;
}
/**
* Returns the full URL of the request including the query string.
* <p/>
* Used as a convenience method for logging purposes.
*
* @param request the request object.
*
* @return the full URL of the request including the query string.
*/
protected String getRequestURL(HttpServletRequest request) {
StringBuffer sb = request.getRequestURL();
if (request.getQueryString() != null) {
sb.append("?").append(request.getQueryString());
}
return sb.toString();
}
/**
* Returns the {@link AuthenticationToken} for the request.
* <p/>
* It looks at the received HTTP cookies and extracts the value of the {@link AuthenticatedURL#AUTH_COOKIE}
* if present. It verifies the signature and if correct it creates the {@link AuthenticationToken} and returns
* it.
* <p/>
* If this method returns <code>null</code> the filter will invoke the configured {@link AuthenticationHandler}
* to perform user authentication.
*
* @param request request object.
*
* @return the Authentication token if the request is authenticated, <code>null</code> otherwise.
*
* @throws IOException thrown if an IO error occurred.
* @throws AuthenticationException thrown if the token is invalid or if it has expired.
*/
protected AuthenticationToken getToken(HttpServletRequest request) throws IOException, AuthenticationException {
AuthenticationToken token = null;
String tokenStr = null;
Cookie[] cookies = request.getCookies();
if (cookies != null) {
for (Cookie cookie : cookies) {
if (cookie.getName().equals(AuthenticatedURL.AUTH_COOKIE)) {
tokenStr = cookie.getValue();
try {
tokenStr = signer.verifyAndExtract(tokenStr);
} catch (SignerException ex) {
throw new AuthenticationException(ex);
}
break;
}
}
}
if (tokenStr != null) {
token = AuthenticationToken.parse(tokenStr);
if (!token.getType().equals(authHandler.getType())) {
throw new AuthenticationException("Invalid AuthenticationToken type");
}
if (token.isExpired()) {
throw new AuthenticationException("AuthenticationToken expired");
}
}
return token;
}
/**
* If the request has a valid authentication token it allows the request to continue to the target resource,
* otherwise it triggers an authentication sequence using the configured {@link AuthenticationHandler}.
*
* @param request the request object.
* @param response the response object.
* @param filterChain the filter chain object.
*
* @throws IOException thrown if an IO error occurred.
* @throws ServletException thrown if a processing error occurred.
*/
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain)
throws IOException, ServletException {
boolean unauthorizedResponse = true;
String unauthorizedMsg = "";
HttpServletRequest httpRequest = (HttpServletRequest) request;
HttpServletResponse httpResponse = (HttpServletResponse) response;
try {
boolean newToken = false;
AuthenticationToken token;
try {
token = getToken(httpRequest);
}
catch (AuthenticationException ex) {
LOG.warn("AuthenticationToken ignored: " + ex.getMessage());
token = null;
}
if (authHandler.managementOperation(token, httpRequest, httpResponse)) {
if (token == null) {
if (LOG.isDebugEnabled()) {
LOG.debug("Request [{}] triggering authentication", getRequestURL(httpRequest));
}
token = authHandler.authenticate(httpRequest, httpResponse);
if (token != null && token.getExpires() != 0 &&
token != AuthenticationToken.ANONYMOUS) {
token.setExpires(System.currentTimeMillis() + getValidity() * 1000);
}
newToken = true;
}
if (token != null) {
unauthorizedResponse = false;
if (LOG.isDebugEnabled()) {
LOG.debug("Request [{}] user [{}] authenticated", getRequestURL(httpRequest), token.getUserName());
}
final AuthenticationToken authToken = token;
httpRequest = new HttpServletRequestWrapper(httpRequest) {
@Override
public String getAuthType() {
return authToken.getType();
}
@Override
public String getRemoteUser() {
return authToken.getUserName();
}
@Override
public Principal getUserPrincipal() {
return (authToken != AuthenticationToken.ANONYMOUS) ? authToken : null;
}
};
if (newToken && !token.isExpired() && token != AuthenticationToken.ANONYMOUS) {
String signedToken = signer.sign(token.toString());
Cookie cookie = createCookie(signedToken);
httpResponse.addCookie(cookie);
}
filterChain.doFilter(httpRequest, httpResponse);
}
} else {
unauthorizedResponse = false;
}
} catch (AuthenticationException ex) {
unauthorizedMsg = ex.toString();
LOG.warn("Authentication exception: " + ex.getMessage(), ex);
}
if (unauthorizedResponse) {
if (!httpResponse.isCommitted()) {
Cookie cookie = createCookie("");
cookie.setMaxAge(0);
httpResponse.addCookie(cookie);
httpResponse.sendError(HttpServletResponse.SC_UNAUTHORIZED, unauthorizedMsg);
}
}
}
/**
* Creates the Hadoop authentiation HTTP cookie.
* <p/>
* It sets the domain and path specified in the configuration.
*
* @param token authentication token for the cookie.
*
* @return the HTTP cookie.
*/
protected Cookie createCookie(String token) {
Cookie cookie = new Cookie(AuthenticatedURL.AUTH_COOKIE, token);
if (getCookieDomain() != null) {
cookie.setDomain(getCookieDomain());
}
if (getCookiePath() != null) {
cookie.setPath(getCookiePath());
}
return cookie;
}
}