From 786df62181ded8f5bda75887707478c64e564994 Mon Sep 17 00:00:00 2001 From: Mark Emlyn David Thomas Date: Mon, 27 Aug 2012 19:03:04 +0000 Subject: [PATCH] Digest improvements: - disable caching of authenticated user in session by default - track server rather than client nonces - better handling of stale nonce values git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1377794 13f79535-47bb-0310-9956-ffa450edef68 --- .../authenticator/DigestAuthenticator.java | 127 +++++++++++------- .../util/ConcurrentMessageDigest.java | 90 +++++++++++++ .../TesterDigestAuthenticatorPerformance.java | 42 +++--- webapps/docs/config/valve.xml | 12 +- 4 files changed, 194 insertions(+), 77 deletions(-) create mode 100644 java/org/apache/catalina/util/ConcurrentMessageDigest.java diff --git a/java/org/apache/catalina/authenticator/DigestAuthenticator.java b/java/org/apache/catalina/authenticator/DigestAuthenticator.java index 0d9c69862e2c..6e7af2f2e80d 100644 --- a/java/org/apache/catalina/authenticator/DigestAuthenticator.java +++ b/java/org/apache/catalina/authenticator/DigestAuthenticator.java @@ -60,6 +60,7 @@ public class DigestAuthenticator extends AuthenticatorBase { public DigestAuthenticator() { super(); + setCache(false); try { if (md5Helper == null) { md5Helper = MessageDigest.getInstance("MD5"); @@ -81,16 +82,16 @@ public DigestAuthenticator() { /** - * List of client nonce values currently being tracked + * List of server nonce values currently being tracked */ - protected Map cnonces; + protected Map nonces; /** - * Maximum number of client nonces to keep in the cache. If not specified, + * Maximum number of server nonces to keep in the cache. If not specified, * the default value of 1000 is used. */ - protected int cnonceCacheSize = 1000; + protected int nonceCacheSize = 1000; /** @@ -120,13 +121,13 @@ public DigestAuthenticator() { // ------------------------------------------------------------- Properties - public int getCnonceCacheSize() { - return cnonceCacheSize; + public int getNonceCacheSize() { + return nonceCacheSize; } - public void setCnonceCacheSize(int cnonceCacheSize) { - this.cnonceCacheSize = cnonceCacheSize; + public void setNonceCacheSize(int nonceCacheSize) { + this.nonceCacheSize = nonceCacheSize; } @@ -231,17 +232,19 @@ public boolean authenticate(Request request, HttpServletResponse response) // Validate any credentials already included with this request String authorization = request.getHeader("authorization"); DigestInfo digestInfo = new DigestInfo(getOpaque(), getNonceValidity(), - getKey(), cnonces, isValidateUri()); + getKey(), nonces, isValidateUri()); if (authorization != null) { - if (digestInfo.validate(request, authorization)) { - principal = digestInfo.authenticate(context.getRealm()); - } + if (digestInfo.parse(request, authorization)) { + if (digestInfo.validate(request)) { + principal = digestInfo.authenticate(context.getRealm()); + } - if (principal != null) { - String username = digestInfo.getUsername(); - register(request, response, principal, - HttpServletRequest.DIGEST_AUTH, username, null); - return (true); + if (principal != null && !digestInfo.isNonceStale()) { + register(request, response, principal, + HttpServletRequest.DIGEST_AUTH, + digestInfo.getUsername(), null); + return true; + } } } @@ -252,11 +255,9 @@ public boolean authenticate(Request request, HttpServletResponse response) String nonce = generateNonce(request); setAuthenticateHeader(request, response, nonce, - digestInfo.isNonceStale()); + principal != null && digestInfo.isNonceStale()); response.sendError(HttpServletResponse.SC_UNAUTHORIZED); - // hres.flushBuffer(); - return (false); - + return false; } @@ -314,7 +315,14 @@ protected String generateNonce(Request request) { ipTimeKey.getBytes(B2CConverter.ISO_8859_1)); } - return currentTime + ":" + MD5Encoder.encode(buffer); + String nonce = currentTime + ":" + MD5Encoder.encode(buffer); + + NonceInfo info = new NonceInfo(currentTime, 100); + synchronized (nonces) { + nonces.put(nonce, info); + } + + return nonce; } @@ -382,7 +390,7 @@ protected synchronized void startInternal() throws LifecycleException { setOpaque(sessionIdGenerator.generateSessionId()); } - cnonces = new LinkedHashMap() { + nonces = new LinkedHashMap() { private static final long serialVersionUID = 1L; private static final long LOG_SUPPRESS_TIME = 5 * 60 * 1000; @@ -394,7 +402,7 @@ protected boolean removeEldestEntry( Map.Entry eldest) { // This is called from a sync so keep it simple long currentTime = System.currentTimeMillis(); - if (size() > getCnonceCacheSize()) { + if (size() > getNonceCacheSize()) { if (lastLog < currentTime && currentTime - eldest.getValue().getTimestamp() < getNonceValidity()) { @@ -415,7 +423,7 @@ private static class DigestInfo { private final String opaque; private final long nonceValidity; private final String key; - private final Map cnonces; + private final Map nonces; private boolean validateUri = true; private String userName = null; @@ -427,16 +435,17 @@ private static class DigestInfo { 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 cnonces, boolean validateUri) { + Map nonces, boolean validateUri) { this.opaque = opaque; this.nonceValidity = nonceValidity; this.key = key; - this.cnonces = cnonces; + this.nonces = nonces; this.validateUri = validateUri; } @@ -446,7 +455,7 @@ public String getUsername() { } - public boolean validate(Request request, String authorization) { + public boolean parse(Request request, String authorization) { // Validate the authorization credentials format if (authorization == null) { return false; @@ -460,7 +469,6 @@ public boolean validate(Request request, String authorization) { String[] tokens = authorization.split(",(?=(?:[^\"]*\"[^\"]*\")+$)"); method = request.getMethod(); - String opaque = null; for (int i = 0; i < tokens.length; i++) { String currentToken = tokens[i]; @@ -501,10 +509,14 @@ public boolean validate(Request request, String authorization) { response = removeQuotes(currentTokenValue); } if ("opaque".equals(currentTokenName)) { - opaque = removeQuotes(currentTokenValue); + opaqueReceived = removeQuotes(currentTokenValue); } } + return true; + } + + public boolean validate(Request request) { if ( (userName == null) || (realmName == null) || (nonce == null) || (uri == null) || (response == null) ) { return false; @@ -547,7 +559,7 @@ public boolean validate(Request request, String authorization) { } // Validate the opaque string - if (!this.opaque.equals(opaque)) { + if (!opaque.equals(opaqueReceived)) { return false; } @@ -566,7 +578,9 @@ public boolean validate(Request request, String authorization) { long currentTime = System.currentTimeMillis(); if ((currentTime - nonceTime) > nonceValidity) { nonceStale = true; - return false; + synchronized (nonces) { + nonces.remove(nonce); + } } String serverIpTimeKey = request.getRemoteAddr() + ":" + nonceTime + ":" + key; @@ -586,7 +600,7 @@ public boolean validate(Request request, String authorization) { } // Validate cnonce and nc - // Check if presence of nc and nonce is consistent with presence of qop + // Check if presence of nc and Cnonce is consistent with presence of qop if (qop == null) { if (cnonce != null || nc != null) { return false; @@ -607,21 +621,18 @@ public boolean validate(Request request, String authorization) { return false; } NonceInfo info; - synchronized (cnonces) { - info = cnonces.get(cnonce); + synchronized (nonces) { + info = nonces.get(nonce); } if (info == null) { - info = new NonceInfo(); + // Nonce is valid but not in cache. It must have dropped out + // of the cache - force a re-authentication + nonceStale = true; } else { - if (count <= info.getCount()) { + if (!info.nonceCountValid(count)) { return false; } } - info.setCount(count); - info.setTimestamp(currentTime); - synchronized (cnonces) { - cnonces.put(cnonce, info); - } } return true; } @@ -648,19 +659,31 @@ public Principal authenticate(Realm realm) { } private static class NonceInfo { - private volatile long count; private volatile long timestamp; - - public void setCount(long l) { - count = l; + private volatile boolean seen[]; + private volatile int offset; + private volatile int count = 0; + + public NonceInfo(long currentTime, int seenWindowSize) { + this.timestamp = currentTime; + seen = new boolean[seenWindowSize]; + offset = seenWindowSize / 2; } - public long getCount() { - return count; - } - - public void setTimestamp(long l) { - timestamp = l; + 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() { diff --git a/java/org/apache/catalina/util/ConcurrentMessageDigest.java b/java/org/apache/catalina/util/ConcurrentMessageDigest.java new file mode 100644 index 000000000000..37104b7f7da6 --- /dev/null +++ b/java/org/apache/catalina/util/ConcurrentMessageDigest.java @@ -0,0 +1,90 @@ +/* + * 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.util; + +import java.security.MessageDigest; +import java.security.NoSuchAlgorithmException; +import java.util.HashMap; +import java.util.Map; +import java.util.Queue; +import java.util.concurrent.ConcurrentLinkedQueue; + +/** + * A thread safe wrapper around {@link MessageDigest} that does not make use + * of ThreadLocal and - broadly - only creates enough MessageDigest objects + * to satisfy the concurrency requirements. + */ +public class ConcurrentMessageDigest { + + private static final Map> queues = + new HashMap<>(); + + + private ConcurrentMessageDigest() { + // Hide default constructor for this utility class + } + + + public static byte[] digest(String algorithm, byte[] input) { + + Queue queue = queues.get(algorithm); + if (queue == null) { + throw new IllegalStateException("Must call init() first"); + } + + MessageDigest md = queue.poll(); + if (md == null) { + try { + md = MessageDigest.getInstance(algorithm); + } catch (NoSuchAlgorithmException e) { + // Ignore. Impossible if init() has been successfully called + // first. + throw new IllegalStateException("Must call init() first"); + } + } + + byte[] result = md.digest(input); + + queue.add(md); + + return result; + } + + + /** + * Ensures that {@link #digest(String, byte[])} and + * {@link #digestAsHex(String, byte[])} will support the specified + * algorithm. This method must be called and return successfully + * before using {@link #digest(String, byte[])} or + * {@link #digestAsHex(String, byte[])}. + * + * @param algorithm The message digest algorithm to be supported + * + * @throws NoSuchAlgorithmException If the algorithm is not supported by the + * JVM + */ + public static void init(String algorithm) throws NoSuchAlgorithmException { + synchronized (queues) { + if (!queues.containsKey(algorithm)) { + MessageDigest md = MessageDigest.getInstance(algorithm); + Queue queue = new ConcurrentLinkedQueue<>(); + queue.add(md); + queues.put(algorithm, queue); + } + } + } +} diff --git a/test/org/apache/catalina/authenticator/TesterDigestAuthenticatorPerformance.java b/test/org/apache/catalina/authenticator/TesterDigestAuthenticatorPerformance.java index 40f064bd6221..923b390c4a4d 100644 --- a/test/org/apache/catalina/authenticator/TesterDigestAuthenticatorPerformance.java +++ b/test/org/apache/catalina/authenticator/TesterDigestAuthenticatorPerformance.java @@ -17,8 +17,7 @@ package org.apache.catalina.authenticator; import java.io.IOException; -import java.security.MessageDigest; -import java.security.NoSuchAlgorithmException; +import java.util.concurrent.atomic.AtomicInteger; import javax.servlet.http.HttpServletResponse; @@ -33,6 +32,7 @@ import org.apache.catalina.deploy.LoginConfig; import org.apache.catalina.filters.TesterResponse; import org.apache.catalina.startup.TestTomcat.MapRealm; +import org.apache.catalina.util.ConcurrentMessageDigest; import org.apache.catalina.util.MD5Encoder; public class TesterDigestAuthenticatorPerformance { @@ -47,6 +47,8 @@ public class TesterDigestAuthenticatorPerformance { private static String REALM = "TestRealm"; private static String QOP = "auth"; + private static final AtomicInteger nonceCount = new AtomicInteger(0); + private DigestAuthenticator authenticator = new DigestAuthenticator(); @@ -60,9 +62,11 @@ public void doTest(int threadCount, int requestCount) throws Exception { TesterRunnable runnables[] = new TesterRunnable[threadCount]; Thread threads[] = new Thread[threadCount]; + String nonce = authenticator.generateNonce(new TesterDigestRequest()); + // Create the runnables & threads for (int i = 0; i < threadCount; i++) { - runnables[i] = new TesterRunnable(requestCount); + runnables[i] = new TesterRunnable(nonce, requestCount); threads[i] = new Thread(runnables[i]); } @@ -100,6 +104,8 @@ public void doTest(int threadCount, int requestCount) throws Exception { @Before public void setUp() throws Exception { + ConcurrentMessageDigest.init("MD5"); + // Configure the Realm MapRealm realm = new MapRealm(); realm.addUser(USER, PWD); @@ -118,15 +124,14 @@ public void setUp() throws Exception { // Make the Context and Realm visible to the Authenticator authenticator.setContainer(context); - // Prevent caching of cnonces so we can the same one for all requests - authenticator.setCnonceCacheSize(0); authenticator.start(); } private class TesterRunnable implements Runnable { - // Number of valid requests required + + private String nonce; private int requestCount; private int success = 0; @@ -136,12 +141,11 @@ private class TesterRunnable implements Runnable { private HttpServletResponse response; // All init code should be in here. run() needs to be quick - public TesterRunnable(int requestCount) throws Exception { + public TesterRunnable(String nonce, int requestCount) throws Exception { + this.nonce = nonce; this.requestCount = requestCount; request = new TesterDigestRequest(); - String nonce = authenticator.generateNonce(request); - request.setAuthHeader(buildDigestResponse(nonce)); request.setContext(authenticator.context); response = new TesterResponse(); @@ -152,6 +156,7 @@ public void run() { long start = System.currentTimeMillis(); for (int i = 0; i < requestCount; i++) { try { + request.setAuthHeader(buildDigestResponse(nonce)); if (authenticator.authenticate(request, response)) { success++; } @@ -172,25 +177,25 @@ public long getTime() { return time; } - private String buildDigestResponse(String nonce) - throws NoSuchAlgorithmException { + private String buildDigestResponse(String nonce) { - String ncString = "00000001"; + String ncString = String.format("%1$08x", + Integer.valueOf(nonceCount.incrementAndGet())); String cnonce = "cnonce"; String a1 = USER + ":" + REALM + ":" + PWD; String a2 = METHOD + ":" + CONTEXT_PATH + URI; - MessageDigest digester = MessageDigest.getInstance("MD5"); - - String md5a1 = MD5Encoder.encode(digester.digest(a1.getBytes())); - String md5a2 = MD5Encoder.encode(digester.digest(a2.getBytes())); + String md5a1 = MD5Encoder.encode( + ConcurrentMessageDigest.digest("MD5", a1.getBytes())); + String md5a2 = MD5Encoder.encode( + ConcurrentMessageDigest.digest("MD5", a2.getBytes())); String response = md5a1 + ":" + nonce + ":" + ncString + ":" + cnonce + ":" + QOP + ":" + md5a2; - String md5response = - MD5Encoder.encode(digester.digest(response.getBytes())); + String md5response = MD5Encoder.encode( + ConcurrentMessageDigest.digest("MD5", response.getBytes())); StringBuilder auth = new StringBuilder(); auth.append("Digest username=\""); @@ -257,6 +262,5 @@ public String getQueryString() { public String getRequestURI() { return CONTEXT_PATH + URI; } - } } diff --git a/webapps/docs/config/valve.xml b/webapps/docs/config/valve.xml index 91e71ae4c259..0b6f1760bdcf 100644 --- a/webapps/docs/config/valve.xml +++ b/webapps/docs/config/valve.xml @@ -847,12 +847,6 @@ org.apache.catalina.authenticator.DigestAuthenticator.

- -

To protect against replay attacks, the DIGEST authenticator tracks - client nonce and nonce count values. This attribute controls the size - of that cache. If not specified, the default value of 1000 is used.

- -

Controls the caching of pages that are protected by security constraints. Setting this to false may help work around @@ -870,6 +864,12 @@ and/or across a cluster.

 + +

To protect against replay attacks, the DIGEST authenticator tracks + server nonce and nonce count values. This attribute controls the size + of that cache. If not specified, the default value of 1000 is used.

+ +

The time, in milliseconds, that a server generated nonce will be considered valid for use in authentication. If not specified, the