/*
* Copyright 2004, 2005, 2006 Acegi Technology Pty Limited
*
* 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.
*/
package org.springframework.security.authentication.encoding;
import java.security.MessageDigest;
import java.util.Base64;
import org.springframework.security.crypto.codec.Utf8;
import org.springframework.util.Assert;
/**
* A version of {@link ShaPasswordEncoder} which supports Ldap SHA and SSHA (salted-SHA)
* encodings. The values are base-64 encoded and have the label "{SHA}" (or "{SSHA}")
* prepended to the encoded hash. These can be made lower-case in the encoded password, if
* required, by setting the <tt>forceLowerCasePrefix</tt> property to true.
*
* Also supports plain text passwords, so can safely be used in cases when both encoded
* and non-encoded passwords are in use or when a null implementation is required.
*
* @author Luke Taylor
*/
public class LdapShaPasswordEncoder implements PasswordEncoder {
// ~ Static fields/initializers
// =====================================================================================
/** The number of bytes in a SHA hash */
private static final int SHA_LENGTH = 20;
private static final String SSHA_PREFIX = "{SSHA}";
private static final String SSHA_PREFIX_LC = SSHA_PREFIX.toLowerCase();
private static final String SHA_PREFIX = "{SHA}";
private static final String SHA_PREFIX_LC = SHA_PREFIX.toLowerCase();
// ~ Instance fields
// ================================================================================================
private boolean forceLowerCasePrefix;
// ~ Constructors
// ===================================================================================================
public LdapShaPasswordEncoder() {
}
// ~ Methods
// ========================================================================================================
private byte[] combineHashAndSalt(byte[] hash, byte[] salt) {
if (salt == null) {
return hash;
}
byte[] hashAndSalt = new byte[hash.length + salt.length];
System.arraycopy(hash, 0, hashAndSalt, 0, hash.length);
System.arraycopy(salt, 0, hashAndSalt, hash.length, salt.length);
return hashAndSalt;
}
/**
* Calculates the hash of password (and salt bytes, if supplied) and returns a base64
* encoded concatenation of the hash and salt, prefixed with {SHA} (or {SSHA} if salt
* was used).
*
* @param rawPass the password to be encoded.
* @param salt the salt. Must be a byte array or null.
*
* @return the encoded password in the specified format
*
*/
public String encodePassword(String rawPass, Object salt) {
MessageDigest sha;
try {
sha = MessageDigest.getInstance("SHA");
sha.update(Utf8.encode(rawPass));
}
catch (java.security.NoSuchAlgorithmException e) {
throw new IllegalStateException("No SHA implementation available!");
}
if (salt != null) {
Assert.isInstanceOf(byte[].class, salt, "Salt value must be a byte array");
sha.update((byte[]) salt);
}
byte[] hash = combineHashAndSalt(sha.digest(), (byte[]) salt);
String prefix;
if (salt == null) {
prefix = forceLowerCasePrefix ? SHA_PREFIX_LC : SHA_PREFIX;
}
else {
prefix = forceLowerCasePrefix ? SSHA_PREFIX_LC : SSHA_PREFIX;
}
return prefix + Utf8.decode(Base64.getEncoder().encode(hash));
}
private byte[] extractSalt(String encPass) {
String encPassNoLabel = encPass.substring(6);
byte[] hashAndSalt = Base64.getDecoder().decode(encPassNoLabel.getBytes());
int saltLength = hashAndSalt.length - SHA_LENGTH;
byte[] salt = new byte[saltLength];
System.arraycopy(hashAndSalt, SHA_LENGTH, salt, 0, saltLength);
return salt;
}
/**
* Checks the validity of an unencoded password against an encoded one in the form
* "{SSHA}sQuQF8vj8Eg2Y1hPdh3bkQhCKQBgjhQI".
*
* @param encPass the actual SSHA or SHA encoded password
* @param rawPass unencoded password to be verified.
* @param salt ignored. If the format is SSHA the salt bytes will be extracted from
* the encoded password.
*
* @return true if they match (independent of the case of the prefix).
*/
public boolean isPasswordValid(final String encPass, final String rawPass, Object salt) {
String prefix = extractPrefix(encPass);
if (prefix == null) {
return encPass.equals(rawPass);
}
if (prefix.equals(SSHA_PREFIX) || prefix.equals(SSHA_PREFIX_LC)) {
salt = extractSalt(encPass);
}
else if (!prefix.equals(SHA_PREFIX) && !prefix.equals(SHA_PREFIX_LC)) {
throw new IllegalArgumentException("Unsupported password prefix '" + prefix
+ "'");
}
else {
// Standard SHA
salt = null;
}
int startOfHash = prefix.length();
String encodedRawPass = encodePassword(rawPass, salt).substring(startOfHash);
return PasswordEncoderUtils
.equals(encodedRawPass, encPass.substring(startOfHash));
}
/**
* Returns the hash prefix or null if there isn't one.
*/
private String extractPrefix(String encPass) {
if (!encPass.startsWith("{")) {
return null;
}
int secondBrace = encPass.lastIndexOf('}');
if (secondBrace < 0) {
throw new IllegalArgumentException(
"Couldn't find closing brace for SHA prefix");
}
return encPass.substring(0, secondBrace + 1);
}
public void setForceLowerCasePrefix(boolean forceLowerCasePrefix) {
this.forceLowerCasePrefix = forceLowerCasePrefix;
}
}