io.netty.handler.ssl.util.FingerprintTrustManagerFactory Maven / Gradle / Ivy
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/*
* Copyright 2014 The Netty Project
*
* The Netty Project 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 io.netty.handler.ssl.util;
import io.netty.buffer.ByteBufUtil;
import io.netty.buffer.Unpooled;
import io.netty.util.concurrent.FastThreadLocal;
import io.netty.util.internal.EmptyArrays;
import io.netty.util.internal.ObjectUtil;
import io.netty.util.internal.StringUtil;
import javax.net.ssl.ManagerFactoryParameters;
import javax.net.ssl.TrustManager;
import javax.net.ssl.TrustManagerFactory;
import javax.net.ssl.X509TrustManager;
import java.security.KeyStore;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.cert.CertificateEncodingException;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.regex.Pattern;
/**
* An {@link TrustManagerFactory} that trusts an X.509 certificate whose SHA1 checksum matches.
*
* NOTE: It is recommended to verify certificates and their chain to prevent
* Man-in-the-middle attacks.
* This {@link TrustManagerFactory} will only verify that the fingerprint of certificates match one
* of the given fingerprints. This procedure is called
* certificate pinning and
* is an effective protection. For maximum security one should verify that the whole certificate chain is as expected.
* It is worth mentioning that certain firewalls, proxies or other appliances found in corporate environments,
* actually perform Man-in-the-middle attacks and thus present a different certificate fingerprint.
*
*
* The SHA1 checksum of an X.509 certificate is calculated from its DER encoded format. You can get the fingerprint of
* an X.509 certificate using the {@code openssl} command. For example:
*
*
* $ openssl x509 -fingerprint -sha1 -in my_certificate.crt
* SHA1 Fingerprint=4E:85:10:55:BC:7B:12:08:D1:EA:0A:12:C9:72:EE:F3:AA:B2:C7:CB
* -----BEGIN CERTIFICATE-----
* MIIBqjCCAROgAwIBAgIJALiT3Nvp0kvmMA0GCSqGSIb3DQEBBQUAMBYxFDASBgNV
* BAMTC2V4YW1wbGUuY29tMCAXDTcwMDEwMTAwMDAwMFoYDzk5OTkxMjMxMjM1OTU5
* WjAWMRQwEgYDVQQDEwtleGFtcGxlLmNvbTCBnzANBgkqhkiG9w0BAQEFAAOBjQAw
* gYkCgYEAnadvODG0QCiHhaFZlLHtr5gLIkDQS8ErZ//KfqeCHTC/KJsl3xYFk0zG
* aCv2FcmkOlokm77qV8qOW2DZdND7WuYzX6nLVuLb+GYxZ7b45iMAbAajvGh8jc9U
* o07fUIahGqTDAIAGCWsoLUOQ9nMzO/8GRHcXJAeQ2MGY2VpCcv0CAwEAATANBgkq
* hkiG9w0BAQUFAAOBgQBpRCnmjmNM0D7yrpkUJpBTNiqinhKLbeOvPWm+YmdInUUs
* LoMu0mZ1IANemLwqbwJJ76fknngeB+YuVAj46SurvVCV6ekwHcbgpW1u063IRwKk
* tQhOBO0HQxldUS4+4MYv/kuvnKkbjfgh5qfWw89Kx4kD+cycpP4yPtgDGk8ZMA==
* -----END CERTIFICATE-----
*
*
*/
public final class FingerprintTrustManagerFactory extends SimpleTrustManagerFactory {
private static final Pattern FINGERPRINT_PATTERN = Pattern.compile("^[0-9a-fA-F:]+$");
private static final Pattern FINGERPRINT_STRIP_PATTERN = Pattern.compile(":");
private static final int SHA1_BYTE_LEN = 20;
private static final int SHA1_HEX_LEN = SHA1_BYTE_LEN * 2;
private static final FastThreadLocal tlmd = new FastThreadLocal() {
@Override
protected MessageDigest initialValue() {
try {
return MessageDigest.getInstance("SHA1");
} catch (NoSuchAlgorithmException e) {
// All Java implementation must have SHA1 digest algorithm.
throw new Error(e);
}
}
};
private final TrustManager tm = new X509TrustManager() {
@Override
public void checkClientTrusted(X509Certificate[] chain, String s) throws CertificateException {
checkTrusted("client", chain);
}
@Override
public void checkServerTrusted(X509Certificate[] chain, String s) throws CertificateException {
checkTrusted("server", chain);
}
private void checkTrusted(String type, X509Certificate[] chain) throws CertificateException {
X509Certificate cert = chain[0];
byte[] fingerprint = fingerprint(cert);
boolean found = false;
for (byte[] allowedFingerprint: fingerprints) {
if (Arrays.equals(fingerprint, allowedFingerprint)) {
found = true;
break;
}
}
if (!found) {
throw new CertificateException(
type + " certificate with unknown fingerprint: " + cert.getSubjectDN());
}
}
private byte[] fingerprint(X509Certificate cert) throws CertificateEncodingException {
MessageDigest md = tlmd.get();
md.reset();
return md.digest(cert.getEncoded());
}
@Override
public X509Certificate[] getAcceptedIssuers() {
return EmptyArrays.EMPTY_X509_CERTIFICATES;
}
};
private final byte[][] fingerprints;
/**
* Creates a new instance.
*
* @param fingerprints a list of SHA1 fingerprints in hexadecimal form
*/
public FingerprintTrustManagerFactory(Iterable fingerprints) {
this(toFingerprintArray(fingerprints));
}
/**
* Creates a new instance.
*
* @param fingerprints a list of SHA1 fingerprints in hexadecimal form
*/
public FingerprintTrustManagerFactory(String... fingerprints) {
this(toFingerprintArray(Arrays.asList(fingerprints)));
}
/**
* Creates a new instance.
*
* @param fingerprints a list of SHA1 fingerprints
*/
public FingerprintTrustManagerFactory(byte[]... fingerprints) {
ObjectUtil.checkNotNull(fingerprints, "fingerprints");
List list = new ArrayList(fingerprints.length);
for (byte[] f: fingerprints) {
if (f == null) {
break;
}
if (f.length != SHA1_BYTE_LEN) {
throw new IllegalArgumentException("malformed fingerprint: " +
ByteBufUtil.hexDump(Unpooled.wrappedBuffer(f)) + " (expected: SHA1)");
}
list.add(f.clone());
}
this.fingerprints = list.toArray(new byte[0][]);
}
private static byte[][] toFingerprintArray(Iterable fingerprints) {
ObjectUtil.checkNotNull(fingerprints, "fingerprints");
List list = new ArrayList();
for (String f: fingerprints) {
if (f == null) {
break;
}
if (!FINGERPRINT_PATTERN.matcher(f).matches()) {
throw new IllegalArgumentException("malformed fingerprint: " + f);
}
f = FINGERPRINT_STRIP_PATTERN.matcher(f).replaceAll("");
if (f.length() != SHA1_HEX_LEN) {
throw new IllegalArgumentException("malformed fingerprint: " + f + " (expected: SHA1)");
}
list.add(StringUtil.decodeHexDump(f));
}
return list.toArray(new byte[0][]);
}
@Override
protected void engineInit(KeyStore keyStore) throws Exception { }
@Override
protected void engineInit(ManagerFactoryParameters managerFactoryParameters) throws Exception { }
@Override
protected TrustManager[] engineGetTrustManagers() {
return new TrustManager[] { tm };
}
}