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EE4J Compatible Implementation for Jakarta Faces API
/*
* Copyright (c) 1997, 2020 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package com.sun.faces.renderkit;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Base64;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.Mac;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import com.sun.faces.RIConstants;
import com.sun.faces.util.FacesLogger;
import jakarta.faces.FacesException;
import jakarta.faces.context.FacesContext;
import jakarta.servlet.http.HttpSession;
/**
*
* This utility class is to provide both encryption and decryption Ciphers to
* ResponseStateManager implementations wishing to provide encryption support.
*
*
*
* The algorithm used to encrypt byte array is AES with CBC.
*
*
*
* Original author Inderjeet Singh, J2EE Blue Prints Team. Modified to suit Faces needs.
*
*/
public final class ByteArrayGuard {
// Log instance for this class
private static final Logger LOGGER = FacesLogger.RENDERKIT.getLogger();
private static final int MAC_LENGTH = 32;
private static final int KEY_LENGTH = 128;
private static final int IV_LENGTH = 16;
private static final String KEY_ALGORITHM = "AES";
private static final String CIPHER_CODE = "AES/CBC/PKCS5Padding";
private static final String MAC_CODE = "HmacSHA256";
private static final String SK_SESSION_KEY = RIConstants.FACES_PREFIX + "SK";
private SecretKey sk;
// ------------------------------------------------------------ Constructors
public ByteArrayGuard() {
try {
setupKeyAndMac();
} catch (Exception e) {
if (LOGGER.isLoggable(Level.SEVERE)) {
LOGGER.log(Level.SEVERE, "Unexpected exception initializing encryption." + " No encryption will be performed.", e);
}
System.err.println("ERROR: Initializing Ciphers");
}
}
// ---------------------------------------------------------- Public Methods
/**
* This method: Encrypts bytes using a cipher. Generates MAC for intialization vector of the cipher Generates MAC for
* encrypted data Returns a byte array consisting of the following concatenated together: |MAC for cnrypted Data | MAC
* for Init Vector | Encrypted Data |
*
* @param bytes The byte array to be encrypted.
* @return the encrypted byte array.
*/
public byte[] encrypt(FacesContext facesContext, byte[] bytes) {
byte[] securedata = null;
try {
// Generate IV
SecureRandom rand = new SecureRandom();
byte[] iv = new byte[16];
rand.nextBytes(iv);
IvParameterSpec ivspec = new IvParameterSpec(iv);
Cipher encryptCipher = Cipher.getInstance(CIPHER_CODE);
SecretKey secKey = getSecretKey(facesContext);
encryptCipher.init(Cipher.ENCRYPT_MODE, secKey, ivspec);
Mac encryptMac = Mac.getInstance(MAC_CODE);
encryptMac.init(secKey);
encryptMac.update(iv);
// encrypt the plaintext
byte[] encdata = encryptCipher.doFinal(bytes);
byte[] macBytes = encryptMac.doFinal(encdata);
byte[] tmp = concatBytes(macBytes, iv);
securedata = concatBytes(tmp, encdata);
} catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException | InvalidAlgorithmParameterException | IllegalStateException
| IllegalBlockSizeException | BadPaddingException e) {
if (LOGGER.isLoggable(Level.SEVERE)) {
LOGGER.log(Level.SEVERE, "Unexpected exception initializing encryption." + " No encryption will be performed.", e);
}
return null;
}
return securedata;
}
/**
* This method decrypts the provided byte array. The decryption is only performed if the regenerated MAC is the same as
* the MAC for the received value.
*
* @param bytes Encrypted byte array to be decrypted.
* @return Decrypted byte array.
*/
public byte[] decrypt(FacesContext facesContext, byte[] bytes) {
try {
// Extract MAC
byte[] macBytes = new byte[MAC_LENGTH];
System.arraycopy(bytes, 0, macBytes, 0, macBytes.length);
// Extract IV
byte[] iv = new byte[IV_LENGTH];
System.arraycopy(bytes, macBytes.length, iv, 0, iv.length);
// Extract encrypted data
byte[] encdata = new byte[bytes.length - macBytes.length - iv.length];
System.arraycopy(bytes, macBytes.length + iv.length, encdata, 0, encdata.length);
IvParameterSpec ivspec = new IvParameterSpec(iv);
SecretKey secKey = getSecretKey(facesContext);
Cipher decryptCipher = Cipher.getInstance(CIPHER_CODE);
decryptCipher.init(Cipher.DECRYPT_MODE, secKey, ivspec);
// verify MAC by regenerating it and comparing it with the received value
Mac decryptMac = Mac.getInstance(MAC_CODE);
decryptMac.init(secKey);
decryptMac.update(iv);
decryptMac.update(encdata);
byte[] macBytesCalculated = decryptMac.doFinal();
if (areArrayEqualsConstantTime(macBytes, macBytesCalculated)) {
// continue only if the MAC was valid
// System.out.println("Valid MAC found!");
byte[] plaindata = decryptCipher.doFinal(encdata);
return plaindata;
} else {
System.err.println("ERROR: MAC did not verify!");
return null;
}
} catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException | InvalidAlgorithmParameterException | IllegalStateException
| IllegalBlockSizeException | BadPaddingException e) {
System.err.println("ERROR: Decrypting:" + e.getCause());
return null; // Signal to Faces runtime
}
}
private boolean areArrayEqualsConstantTime(byte[] array1, byte[] array2) {
boolean result = true;
for (int i = 0; i < array1.length; i++) {
if (array1[i] != array2[i]) {
result = false;
}
}
return result;
}
// --------------------------------------------------------- Private Methods
/**
* Generates secret key. Initializes MAC(s).
*/
private void setupKeyAndMac() {
/*
* Lets see if an encoded key was given to the application, if so use it and skip the code to generate it.
*/
try {
InitialContext context = new InitialContext();
String encodedKeyArray = (String) context.lookup("java:comp/env/faces/ClientSideSecretKey");
byte[] keyArray = Base64.getDecoder().decode(encodedKeyArray);
sk = new SecretKeySpec(keyArray, KEY_ALGORITHM);
} catch (NamingException exception) {
if (LOGGER.isLoggable(Level.FINEST)) {
LOGGER.log(Level.FINEST, "Unable to find the encoded key.", exception);
}
}
if (sk == null) {
try {
KeyGenerator kg = KeyGenerator.getInstance(KEY_ALGORITHM);
kg.init(KEY_LENGTH); // 256 if you're using the Unlimited Policy Files
sk = kg.generateKey();
// System.out.print("SecretKey: " + DatatypeConverter.printBase64Binary(sk.getEncoded()));
} catch (Exception e) {
throw new FacesException(e);
}
}
}
/**
* This method concatenates two byte arrays
*
* @return a byte array of array1||array2
* @param array1 first byte array to be concatenated
* @param array2 second byte array to be concatenated
*/
private static byte[] concatBytes(byte[] array1, byte[] array2) {
byte[] cBytes = new byte[array1.length + array2.length];
try {
System.arraycopy(array1, 0, cBytes, 0, array1.length);
System.arraycopy(array2, 0, cBytes, array1.length, array2.length);
} catch (Exception e) {
throw new FacesException(e);
}
return cBytes;
}
private SecretKey getSecretKey(FacesContext facesContext) {
SecretKey result = sk;
Object sessionObj;
if (null != (sessionObj = facesContext.getExternalContext().getSession(false))) {
// Don't break on portlets.
if (sessionObj instanceof HttpSession) {
HttpSession session = (HttpSession) sessionObj;
result = (SecretKey) session.getAttribute(SK_SESSION_KEY);
if (null == result) {
session.setAttribute(SK_SESSION_KEY, sk);
result = sk;
}
}
}
return result;
}
}