Java tutorial
/* * (C) Copyright 2006-2014 Nuxeo SA (http://nuxeo.com/) and others. * * 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. * * Contributors: * Florent Guillaume */ package org.nuxeo.ecm.core.blob.binary; import java.io.BufferedInputStream; import java.io.BufferedOutputStream; import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.FilterOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.lang.reflect.Field; import java.security.GeneralSecurityException; import java.security.Key; import java.security.KeyStore; import java.security.MessageDigest; import java.security.SecureRandom; import java.util.Arrays; import java.util.Map; import java.util.Random; import javax.crypto.BadPaddingException; import javax.crypto.Cipher; import javax.crypto.CipherInputStream; import javax.crypto.SecretKeyFactory; import javax.crypto.spec.IvParameterSpec; import javax.crypto.spec.PBEKeySpec; import javax.crypto.spec.SecretKeySpec; import org.apache.commons.io.IOUtils; import org.apache.commons.lang.StringUtils; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.nuxeo.ecm.core.api.NuxeoException; import org.nuxeo.runtime.api.Framework; /** * A binary manager that encrypts binaries on the filesystem using AES. * <p> * The configuration holds the keystore information to retrieve the AES key, or the * password that is used to generate a per-file key using PBKDF2. This configuration comes from the * {@code <property name="key">...</property>} of the binary manager configuration. * <p> * The configuration has the form {@code key1=value1,key2=value2,...} where the possible keys are, for keystore use: * <ul> * <li>keyStoreType: the keystore type, for instance JCEKS * <li>keyStoreFile: the path to the keystore, if applicable * <li>keyStorePassword: the keystore password * <li>keyAlias: the alias (name) of the key in the keystore * <li>keyPassword: the key password * </ul> * <p> * And for PBKDF2 use: * <ul> * <li>password: the password * </ul> * <p> * To encrypt a binary, an AES key is needed. This key can be retrieved from a keystore, or generated from a password * using PBKDF2 (in which case each stored file contains a different salt for security reasons). The file format is * described in {@link #storeAndDigest(InputStream, OutputStream)}. * <p> * While the binary is being used by the application, a temporarily-decrypted file is held in a temporary directory. It * is removed as soon as possible. * <p> * Note: if the Java Cryptographic Extension (JCE) is not configured for 256-bit key length, you may get an exception * "java.security.InvalidKeyException: Illegal key size or default parameters". If this is the case, go to <a * href="http://www.oracle.com/technetwork/java/javase/downloads/index.html" >Oracle Java SE Downloads</a> and download * and install the Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files for your JDK. * * @since 6.0 */ public class AESBinaryManager extends LocalBinaryManager { private static final Log log = LogFactory.getLog(AESBinaryManager.class); protected static final byte[] FILE_MAGIC = new byte[] { 'N', 'U', 'X', 'E', 'O', 'C', 'R', 'Y', 'P', 'T' }; protected static final int FILE_VERSION_1 = 1; protected static final int USE_KEYSTORE = 1; protected static final int USE_PBKDF2 = 2; protected static final String AES = "AES"; protected static final String AES_CBC_PKCS5_PADDING = "AES/CBC/PKCS5Padding"; protected static final String PBKDF2_WITH_HMAC_SHA1 = "PBKDF2WithHmacSHA1"; protected static final int PBKDF2_ITERATIONS = 10000; // AES-256 protected static final int PBKDF2_KEY_LENGTH = 256; protected static final String PARAM_PASSWORD = "password"; protected static final String PARAM_KEY_STORE_TYPE = "keyStoreType"; protected static final String PARAM_KEY_STORE_FILE = "keyStoreFile"; protected static final String PARAM_KEY_STORE_PASSWORD = "keyStorePassword"; protected static final String PARAM_KEY_ALIAS = "keyAlias"; protected static final String PARAM_KEY_PASSWORD = "keyPassword"; // for sanity check during reads private static final int MAX_SALT_LEN = 1024; // for sanity check during reads private static final int MAX_IV_LEN = 1024; // Random instances are thread-safe protected static final Random RANDOM = new SecureRandom(); // the digest from the root descriptor protected String digestAlgorithm; protected boolean usePBKDF2; protected String password; protected String keyStoreType; protected String keyStoreFile; protected String keyStorePassword; protected String keyAlias; protected String keyPassword; public AESBinaryManager() { setUnlimitedJCEPolicy(); } /** * By default the JRE may ship with restricted key length. Instead of having administrators download the Java * Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files from * http://www.oracle.com/technetwork/java/javase/downloads/index.html, we attempt to directly unrestrict the JCE * using reflection. * <p> * This is not possible anymore since 8u102 and https://bugs.openjdk.java.net/browse/JDK-8149417 */ protected static boolean setUnlimitedJCEPolicy() { try { Field field = Class.forName("javax.crypto.JceSecurity").getDeclaredField("isRestricted"); field.setAccessible(true); if (Boolean.TRUE.equals(field.get(null))) { log.info("Setting JCE Unlimited Strength"); field.set(null, Boolean.FALSE); } return true; } catch (ReflectiveOperationException | SecurityException | IllegalArgumentException e) { log.debug("Cannot check/set JCE Unlimited Strength", e); return false; } } @Override public void initialize(String blobProviderId, Map<String, String> properties) throws IOException { super.initialize(blobProviderId, properties); digestAlgorithm = getDigestAlgorithm(); String options = properties.get(BinaryManager.PROP_KEY); // TODO parse options from properties directly if (StringUtils.isBlank(options)) { throw new NuxeoException("Missing key for " + getClass().getSimpleName()); } initializeOptions(options); } protected void initializeOptions(String options) { for (String option : options.split(",")) { String[] split = option.split("=", 2); if (split.length != 2) { throw new NuxeoException("Unrecognized option: " + option); } String value = StringUtils.defaultIfBlank(split[1], null); switch (split[0]) { case PARAM_PASSWORD: password = value; break; case PARAM_KEY_STORE_TYPE: keyStoreType = value; break; case PARAM_KEY_STORE_FILE: keyStoreFile = value; break; case PARAM_KEY_STORE_PASSWORD: keyStorePassword = value; break; case PARAM_KEY_ALIAS: keyAlias = value; break; case PARAM_KEY_PASSWORD: keyPassword = value; break; default: throw new NuxeoException("Unrecognized option: " + option); } } usePBKDF2 = password != null; if (usePBKDF2) { if (keyStoreType != null) { throw new NuxeoException("Cannot use " + PARAM_KEY_STORE_TYPE + " with " + PARAM_PASSWORD); } if (keyStoreFile != null) { throw new NuxeoException("Cannot use " + PARAM_KEY_STORE_FILE + " with " + PARAM_PASSWORD); } if (keyStorePassword != null) { throw new NuxeoException("Cannot use " + PARAM_KEY_STORE_PASSWORD + " with " + PARAM_PASSWORD); } if (keyAlias != null) { throw new NuxeoException("Cannot use " + PARAM_KEY_ALIAS + " with " + PARAM_PASSWORD); } if (keyPassword != null) { throw new NuxeoException("Cannot use " + PARAM_KEY_PASSWORD + " with " + PARAM_PASSWORD); } } else { if (keyStoreType == null) { throw new NuxeoException("Missing " + PARAM_KEY_STORE_TYPE); } // keystore file is optional if (keyStoreFile == null && keyStorePassword != null) { throw new NuxeoException("Missing " + PARAM_KEY_STORE_PASSWORD); } if (keyAlias == null) { throw new NuxeoException("Missing " + PARAM_KEY_ALIAS); } if (keyPassword == null) { keyPassword = keyStorePassword; } } } /** * Gets the password for PBKDF2. * <p> * The caller must clear it from memory when done with it by calling {@link #clearPassword}. */ protected char[] getPassword() { return password.toCharArray(); } /** * Clears a password from memory. */ protected void clearPassword(char[] password) { if (password != null) { Arrays.fill(password, '\0'); } } /** * Generates an AES key from the password using PBKDF2. * * @param salt the salt */ protected Key generateSecretKey(byte[] salt) throws GeneralSecurityException { char[] password = getPassword(); SecretKeyFactory factory = SecretKeyFactory.getInstance(PBKDF2_WITH_HMAC_SHA1); PBEKeySpec spec = new PBEKeySpec(password, salt, PBKDF2_ITERATIONS, PBKDF2_KEY_LENGTH); clearPassword(password); Key derived = factory.generateSecret(spec); spec.clearPassword(); return new SecretKeySpec(derived.getEncoded(), AES); } /** * Gets the AES key from the keystore. */ protected Key getSecretKey() throws GeneralSecurityException, IOException { KeyStore keyStore = KeyStore.getInstance(keyStoreType); char[] kspw = keyStorePassword == null ? null : keyStorePassword.toCharArray(); if (keyStoreFile != null) { try (InputStream in = new BufferedInputStream(new FileInputStream(keyStoreFile))) { keyStore.load(in, kspw); } } else { // some keystores are not backed by a file keyStore.load(null, kspw); } clearPassword(kspw); char[] kpw = keyPassword == null ? null : keyPassword.toCharArray(); Key key = keyStore.getKey(keyAlias, kpw); clearPassword(kpw); return key; } @Override protected Binary getBinary(InputStream in) throws IOException { // write to a tmp file that will be used by the returned Binary // TODO if stream source, avoid copy (no-copy optimization) File tmp = File.createTempFile("bin_", ".tmp", tmpDir); Framework.trackFile(tmp, tmp); OutputStream out = new BufferedOutputStream(new FileOutputStream(tmp)); IOUtils.copy(in, out); in.close(); out.close(); // encrypt an digest into final file InputStream nin = new BufferedInputStream(new FileInputStream(tmp)); String digest = storeAndDigest(nin); // calls our storeAndDigest // return a binary on our tmp file return new Binary(tmp, digest, blobProviderId); } @Override public Binary getBinary(String digest) { File file = getFileForDigest(digest, false); if (file == null) { log.warn("Invalid digest format: " + digest); return null; } if (!file.exists()) { return null; } File tmp; try { tmp = File.createTempFile("bin_", ".tmp", tmpDir); Framework.trackFile(tmp, tmp); OutputStream out = new BufferedOutputStream(new FileOutputStream(tmp)); InputStream in = new BufferedInputStream(new FileInputStream(file)); try { decrypt(in, out); } finally { in.close(); out.close(); } } catch (IOException e) { throw new RuntimeException(e); } // return a binary on our tmp file return new Binary(tmp, digest, blobProviderId); } @Override protected String storeAndDigest(InputStream in) throws IOException { File tmp = File.createTempFile("create_", ".tmp", tmpDir); OutputStream out = new BufferedOutputStream(new FileOutputStream(tmp)); /* * First, write the input stream to a temporary file, while computing a digest. */ try { String digest; try { digest = storeAndDigest(in, out); } finally { in.close(); out.close(); } /* * Move the tmp file to its destination. */ File file = getFileForDigest(digest, true); atomicMove(tmp, file); return digest; } finally { tmp.delete(); } } /** * Encrypts the given input stream into the given output stream, while also computing the digest of the input * stream. * <p> * File format version 1 (values are in network order): * <ul> * <li>10 bytes: magic number "NUXEOCRYPT" * <li>1 byte: file format version = 1 * <li>1 byte: use keystore = 1, use PBKDF2 = 2 * <li>if use PBKDF2: * <ul> * <li>4 bytes: salt length = n * <li>n bytes: salt data * </ul> * <li>4 bytes: IV length = p * <li>p bytes: IV data * <li>x bytes: encrypted stream * </ul> * * @param in the input stream containing the data * @param file the file containing the encrypted data * @return the digest of the input stream */ @Override public String storeAndDigest(InputStream in, OutputStream out) throws IOException { out.write(FILE_MAGIC); DataOutputStream data = new DataOutputStream(out); data.writeByte(FILE_VERSION_1); try { // get digest to use MessageDigest messageDigest = MessageDigest.getInstance(digestAlgorithm); // secret key Key secret; if (usePBKDF2) { data.writeByte(USE_PBKDF2); // generate a salt byte[] salt = new byte[16]; RANDOM.nextBytes(salt); // generate secret key secret = generateSecretKey(salt); // write salt data.writeInt(salt.length); data.write(salt); } else { data.writeByte(USE_KEYSTORE); // find secret key from keystore secret = getSecretKey(); } // cipher Cipher cipher = Cipher.getInstance(AES_CBC_PKCS5_PADDING); cipher.init(Cipher.ENCRYPT_MODE, secret); // write IV byte[] iv = cipher.getIV(); data.writeInt(iv.length); data.write(iv); // digest and write the encrypted data CipherAndDigestOutputStream cipherOut = new CipherAndDigestOutputStream(out, cipher, messageDigest); IOUtils.copy(in, cipherOut); cipherOut.close(); byte[] digest = cipherOut.getDigest(); return toHexString(digest); } catch (GeneralSecurityException e) { throw new NuxeoException(e); } } /** * Decrypts the given input stream into the given output stream. */ protected void decrypt(InputStream in, OutputStream out) throws IOException { byte[] magic = new byte[FILE_MAGIC.length]; IOUtils.read(in, magic); if (!Arrays.equals(magic, FILE_MAGIC)) { throw new IOException("Invalid file (bad magic)"); } DataInputStream data = new DataInputStream(in); byte magicvers = data.readByte(); if (magicvers != FILE_VERSION_1) { throw new IOException("Invalid file (bad version)"); } byte usepb = data.readByte(); if (usepb == USE_PBKDF2) { if (!usePBKDF2) { throw new NuxeoException("File requires PBKDF2 password"); } } else if (usepb == USE_KEYSTORE) { if (usePBKDF2) { throw new NuxeoException("File requires keystore"); } } else { throw new IOException("Invalid file (bad use)"); } try { // secret key Key secret; if (usePBKDF2) { // read salt first int saltLen = data.readInt(); if (saltLen <= 0 || saltLen > MAX_SALT_LEN) { throw new NuxeoException("Invalid salt length: " + saltLen); } byte[] salt = new byte[saltLen]; data.read(salt, 0, saltLen); secret = generateSecretKey(salt); } else { secret = getSecretKey(); } // read IV int ivLen = data.readInt(); if (ivLen <= 0 || ivLen > MAX_IV_LEN) { throw new NuxeoException("Invalid IV length: " + ivLen); } byte[] iv = new byte[ivLen]; data.read(iv, 0, ivLen); // cipher Cipher cipher; cipher = Cipher.getInstance(AES_CBC_PKCS5_PADDING); cipher.init(Cipher.DECRYPT_MODE, secret, new IvParameterSpec(iv)); // read the encrypted data try (InputStream cipherIn = new CipherInputStream(in, cipher)) { IOUtils.copy(cipherIn, out); } catch (IOException e) { Throwable cause = e.getCause(); if (cause != null && cause instanceof BadPaddingException) { throw new NuxeoException(cause.getMessage(), e); } } } catch (GeneralSecurityException e) { throw new NuxeoException(e); } } /** * A {@link javax.crypto.CipherOutputStream CipherOutputStream} that also does a digest of the original stream at * the same time. */ public static class CipherAndDigestOutputStream extends FilterOutputStream { protected Cipher cipher; protected OutputStream out; protected MessageDigest messageDigest; protected byte[] digest; public CipherAndDigestOutputStream(OutputStream out, Cipher cipher, MessageDigest messageDigest) { super(out); this.out = out; this.cipher = cipher; this.messageDigest = messageDigest; } public byte[] getDigest() { return digest; } @Override public void write(int b) throws IOException { write(new byte[] { (byte) b }, 0, 1); } @Override public void write(byte b[], int off, int len) throws IOException { messageDigest.update(b, off, len); byte[] bytes = cipher.update(b, off, len); if (bytes != null) { out.write(bytes); bytes = null; // help GC } } @Override public void flush() throws IOException { out.flush(); } @Override public void close() throws IOException { digest = messageDigest.digest(); try { byte[] bytes = cipher.doFinal(); out.write(bytes); bytes = null; // help GC } catch (GeneralSecurityException e) { throw new NuxeoException(e); } try { flush(); } finally { out.close(); } } } }