org.apache.catalina.authenticator.DigestAuthenticator Maven / Gradle / Ivy
/*
* 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.catalina.authenticator;
import java.io.IOException;
import java.io.StringReader;
import java.nio.charset.StandardCharsets;
import java.security.Principal;
import java.util.LinkedHashMap;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.catalina.LifecycleException;
import org.apache.catalina.Realm;
import org.apache.catalina.connector.Request;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import org.apache.tomcat.util.http.parser.Authorization;
import org.apache.tomcat.util.security.ConcurrentMessageDigest;
import org.apache.tomcat.util.security.MD5Encoder;
/**
* An Authenticator and Valve implementation of HTTP DIGEST
* Authentication (see RFC 2069).
*
* @author Craig R. McClanahan
* @author Remy Maucherat
*/
public class DigestAuthenticator extends AuthenticatorBase {
private final Log log = LogFactory.getLog(DigestAuthenticator.class); // must not be static
// -------------------------------------------------------------- Constants
/**
* Tomcat's DIGEST implementation only supports auth quality of protection.
*/
protected static final String QOP = "auth";
// ----------------------------------------------------------- Constructors
public DigestAuthenticator() {
super();
setCache(false);
}
// ----------------------------------------------------- Instance Variables
/**
* List of server nonce values currently being tracked
*/
protected Map nonces;
/**
* The last timestamp used to generate a nonce. Each nonce should get a
* unique timestamp.
*/
protected long lastTimestamp = 0;
protected final Object lastTimestampLock = new Object();
/**
* Maximum number of server nonces to keep in the cache. If not specified,
* the default value of 1000 is used.
*/
protected int nonceCacheSize = 1000;
/**
* The window size to use to track seen nonce count values for a given
* nonce. If not specified, the default of 100 is used.
*/
protected int nonceCountWindowSize = 100;
/**
* Private key.
*/
protected String key = null;
/**
* How long server nonces are valid for in milliseconds. Defaults to 5
* minutes.
*/
protected long nonceValidity = 5 * 60 * 1000;
/**
* Opaque string.
*/
protected String opaque;
/**
* Should the URI be validated as required by RFC2617? Can be disabled in
* reverse proxies where the proxy has modified the URI.
*/
protected boolean validateUri = true;
// ------------------------------------------------------------- Properties
public int getNonceCountWindowSize() {
return nonceCountWindowSize;
}
public void setNonceCountWindowSize(int nonceCountWindowSize) {
this.nonceCountWindowSize = nonceCountWindowSize;
}
public int getNonceCacheSize() {
return nonceCacheSize;
}
public void setNonceCacheSize(int nonceCacheSize) {
this.nonceCacheSize = nonceCacheSize;
}
public String getKey() {
return key;
}
public void setKey(String key) {
this.key = key;
}
public long getNonceValidity() {
return nonceValidity;
}
public void setNonceValidity(long nonceValidity) {
this.nonceValidity = nonceValidity;
}
public String getOpaque() {
return opaque;
}
public void setOpaque(String opaque) {
this.opaque = opaque;
}
public boolean isValidateUri() {
return validateUri;
}
public void setValidateUri(boolean validateUri) {
this.validateUri = validateUri;
}
// --------------------------------------------------------- Public Methods
/**
* Authenticate the user making this request, based on the specified
* login configuration. Return true if any specified
* constraint has been satisfied, or false if we have
* created a response challenge already.
*
* @param request Request we are processing
* @param response Response we are creating
*
* @exception IOException if an input/output error occurs
*/
@Override
protected boolean doAuthenticate(Request request, HttpServletResponse response)
throws IOException {
// NOTE: We don't try to reauthenticate using any existing SSO session,
// because that will only work if the original authentication was
// BASIC or FORM, which are less secure than the DIGEST auth-type
// specified for this webapp
//
// Change to true below to allow previous FORM or BASIC authentications
// to authenticate users for this webapp
// TODO make this a configurable attribute (in SingleSignOn??)
if (checkForCachedAuthentication(request, response, false)) {
return true;
}
// Validate any credentials already included with this request
Principal principal = null;
String authorization = request.getHeader("authorization");
DigestInfo digestInfo = new DigestInfo(getOpaque(), getNonceValidity(),
getKey(), nonces, isValidateUri());
if (authorization != null) {
if (digestInfo.parse(request, authorization)) {
if (digestInfo.validate(request)) {
principal = digestInfo.authenticate(context.getRealm());
}
if (principal != null && !digestInfo.isNonceStale()) {
register(request, response, principal,
HttpServletRequest.DIGEST_AUTH,
digestInfo.getUsername(), null);
return true;
}
}
}
// Send an "unauthorized" response and an appropriate challenge
// Next, generate a nonce token (that is a token which is supposed
// to be unique).
String nonce = generateNonce(request);
setAuthenticateHeader(request, response, nonce,
principal != null && digestInfo.isNonceStale());
response.sendError(HttpServletResponse.SC_UNAUTHORIZED);
return false;
}
@Override
protected String getAuthMethod() {
return HttpServletRequest.DIGEST_AUTH;
}
// ------------------------------------------------------ Protected Methods
/**
* Removes the quotes on a string. RFC2617 states quotes are optional for
* all parameters except realm.
*
* @param quotedString The quoted string
* @param quotesRequired true if quotes were required
* @return The unquoted string
*/
protected static String removeQuotes(String quotedString,
boolean quotesRequired) {
//support both quoted and non-quoted
if (quotedString.length() > 0 && quotedString.charAt(0) != '"' &&
!quotesRequired) {
return quotedString;
} else if (quotedString.length() > 2) {
return quotedString.substring(1, quotedString.length() - 1);
} else {
return "";
}
}
/**
* Removes the quotes on a string.
*
* @param quotedString The quoted string
* @return The unquoted string
*/
protected static String removeQuotes(String quotedString) {
return removeQuotes(quotedString, false);
}
/**
* Generate a unique token. The token is generated according to the
* following pattern. NOnceToken = Base64 ( MD5 ( client-IP ":"
* time-stamp ":" private-key ) ).
*
* @param request HTTP Servlet request
* @return The generated nonce
*/
protected String generateNonce(Request request) {
long currentTime = System.currentTimeMillis();
synchronized (lastTimestampLock) {
if (currentTime > lastTimestamp) {
lastTimestamp = currentTime;
} else {
currentTime = ++lastTimestamp;
}
}
String ipTimeKey =
request.getRemoteAddr() + ":" + currentTime + ":" + getKey();
byte[] buffer = ConcurrentMessageDigest.digestMD5(
ipTimeKey.getBytes(StandardCharsets.ISO_8859_1));
String nonce = currentTime + ":" + MD5Encoder.encode(buffer);
NonceInfo info = new NonceInfo(currentTime, getNonceCountWindowSize());
synchronized (nonces) {
nonces.put(nonce, info);
}
return nonce;
}
/**
* Generates the WWW-Authenticate header.
*
* The header MUST follow this template :
*
* WWW-Authenticate = "WWW-Authenticate" ":" "Digest"
* digest-challenge
*
* digest-challenge = 1#( realm | [ domain ] | nonce |
* [ digest-opaque ] |[ stale ] | [ algorithm ] )
*
* realm = "realm" "=" realm-value
* realm-value = quoted-string
* domain = "domain" "=" <"> 1#URI <">
* nonce = "nonce" "=" nonce-value
* nonce-value = quoted-string
* opaque = "opaque" "=" quoted-string
* stale = "stale" "=" ( "true" | "false" )
* algorithm = "algorithm" "=" ( "MD5" | token )
*
*
* @param request HTTP Servlet request
* @param response HTTP Servlet response
* @param nonce nonce token
* @param isNonceStale true to add a stale parameter
*/
protected void setAuthenticateHeader(HttpServletRequest request,
HttpServletResponse response,
String nonce,
boolean isNonceStale) {
String realmName = getRealmName(context);
String authenticateHeader;
if (isNonceStale) {
authenticateHeader = "Digest realm=\"" + realmName + "\", " +
"qop=\"" + QOP + "\", nonce=\"" + nonce + "\", " + "opaque=\"" +
getOpaque() + "\", stale=true";
} else {
authenticateHeader = "Digest realm=\"" + realmName + "\", " +
"qop=\"" + QOP + "\", nonce=\"" + nonce + "\", " + "opaque=\"" +
getOpaque() + "\"";
}
response.setHeader(AUTH_HEADER_NAME, authenticateHeader);
}
// ------------------------------------------------------- Lifecycle Methods
@Override
protected synchronized void startInternal() throws LifecycleException {
super.startInternal();
// Generate a random secret key
if (getKey() == null) {
setKey(sessionIdGenerator.generateSessionId());
}
// Generate the opaque string the same way
if (getOpaque() == null) {
setOpaque(sessionIdGenerator.generateSessionId());
}
nonces = new LinkedHashMap() {
private static final long serialVersionUID = 1L;
private static final long LOG_SUPPRESS_TIME = 5 * 60 * 1000;
private long lastLog = 0;
@Override
protected boolean removeEldestEntry(
Map.Entry eldest) {
// This is called from a sync so keep it simple
long currentTime = System.currentTimeMillis();
if (size() > getNonceCacheSize()) {
if (lastLog < currentTime &&
currentTime - eldest.getValue().getTimestamp() <
getNonceValidity()) {
// Replay attack is possible
log.warn(sm.getString(
"digestAuthenticator.cacheRemove"));
lastLog = currentTime + LOG_SUPPRESS_TIME;
}
return true;
}
return false;
}
};
}
public static class DigestInfo {
private final String opaque;
private final long nonceValidity;
private final String key;
private final Map nonces;
private boolean validateUri = true;
private String userName = null;
private String method = null;
private String uri = null;
private String response = null;
private String nonce = null;
private String nc = null;
private String cnonce = null;
private String realmName = null;
private String qop = null;
private String opaqueReceived = null;
private boolean nonceStale = false;
public DigestInfo(String opaque, long nonceValidity, String key,
Map nonces, boolean validateUri) {
this.opaque = opaque;
this.nonceValidity = nonceValidity;
this.key = key;
this.nonces = nonces;
this.validateUri = validateUri;
}
public String getUsername() {
return userName;
}
public boolean parse(Request request, String authorization) {
// Validate the authorization credentials format
if (authorization == null) {
return false;
}
Map directives;
try {
directives = Authorization.parseAuthorizationDigest(
new StringReader(authorization));
} catch (IOException e) {
return false;
}
if (directives == null) {
return false;
}
method = request.getMethod();
userName = directives.get("username");
realmName = directives.get("realm");
nonce = directives.get("nonce");
nc = directives.get("nc");
cnonce = directives.get("cnonce");
qop = directives.get("qop");
uri = directives.get("uri");
response = directives.get("response");
opaqueReceived = directives.get("opaque");
return true;
}
public boolean validate(Request request) {
if ( (userName == null) || (realmName == null) || (nonce == null)
|| (uri == null) || (response == null) ) {
return false;
}
// Validate the URI - should match the request line sent by client
if (validateUri) {
String uriQuery;
String query = request.getQueryString();
if (query == null) {
uriQuery = request.getRequestURI();
} else {
uriQuery = request.getRequestURI() + "?" + query;
}
if (!uri.equals(uriQuery)) {
// Some clients (older Android) use an absolute URI for
// DIGEST but a relative URI in the request line.
// request. 2.3.5 < fixed Android version <= 4.0.3
String host = request.getHeader("host");
String scheme = request.getScheme();
if (host != null && !uriQuery.startsWith(scheme)) {
StringBuilder absolute = new StringBuilder();
absolute.append(scheme);
absolute.append("://");
absolute.append(host);
absolute.append(uriQuery);
if (!uri.equals(absolute.toString())) {
return false;
}
} else {
return false;
}
}
}
// Validate the Realm name
String lcRealm = getRealmName(request.getContext());
if (!lcRealm.equals(realmName)) {
return false;
}
// Validate the opaque string
if (!opaque.equals(opaqueReceived)) {
return false;
}
// Validate nonce
int i = nonce.indexOf(':');
if (i < 0 || (i + 1) == nonce.length()) {
return false;
}
long nonceTime;
try {
nonceTime = Long.parseLong(nonce.substring(0, i));
} catch (NumberFormatException nfe) {
return false;
}
String md5clientIpTimeKey = nonce.substring(i + 1);
long currentTime = System.currentTimeMillis();
if ((currentTime - nonceTime) > nonceValidity) {
nonceStale = true;
synchronized (nonces) {
nonces.remove(nonce);
}
}
String serverIpTimeKey =
request.getRemoteAddr() + ":" + nonceTime + ":" + key;
byte[] buffer = ConcurrentMessageDigest.digestMD5(
serverIpTimeKey.getBytes(StandardCharsets.ISO_8859_1));
String md5ServerIpTimeKey = MD5Encoder.encode(buffer);
if (!md5ServerIpTimeKey.equals(md5clientIpTimeKey)) {
return false;
}
// Validate qop
if (qop != null && !QOP.equals(qop)) {
return false;
}
// Validate cnonce and nc
// Check if presence of nc and Cnonce is consistent with presence of qop
if (qop == null) {
if (cnonce != null || nc != null) {
return false;
}
} else {
if (cnonce == null || nc == null) {
return false;
}
// RFC 2617 says nc must be 8 digits long. Older Android clients
// use 6. 2.3.5 < fixed Android version <= 4.0.3
if (nc.length() < 6 || nc.length() > 8) {
return false;
}
long count;
try {
count = Long.parseLong(nc, 16);
} catch (NumberFormatException nfe) {
return false;
}
NonceInfo info;
synchronized (nonces) {
info = nonces.get(nonce);
}
if (info == null) {
// Nonce is valid but not in cache. It must have dropped out
// of the cache - force a re-authentication
nonceStale = true;
} else {
if (!info.nonceCountValid(count)) {
return false;
}
}
}
return true;
}
public boolean isNonceStale() {
return nonceStale;
}
public Principal authenticate(Realm realm) {
// Second MD5 digest used to calculate the digest :
// MD5(Method + ":" + uri)
String a2 = method + ":" + uri;
byte[] buffer = ConcurrentMessageDigest.digestMD5(
a2.getBytes(StandardCharsets.ISO_8859_1));
String md5a2 = MD5Encoder.encode(buffer);
return realm.authenticate(userName, response, nonce, nc, cnonce,
qop, realmName, md5a2);
}
}
public static class NonceInfo {
private final long timestamp;
private final boolean seen[];
private final int offset;
private int count = 0;
public NonceInfo(long currentTime, int seenWindowSize) {
this.timestamp = currentTime;
seen = new boolean[seenWindowSize];
offset = seenWindowSize / 2;
}
public synchronized boolean nonceCountValid(long nonceCount) {
if ((count - offset) >= nonceCount ||
(nonceCount > count - offset + seen.length)) {
return false;
}
int checkIndex = (int) ((nonceCount + offset) % seen.length);
if (seen[checkIndex]) {
return false;
} else {
seen[checkIndex] = true;
seen[count % seen.length] = false;
count++;
return true;
}
}
public long getTimestamp() {
return timestamp;
}
}
}