/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at
* trunk/opends/resource/legal-notices/OpenDS.LICENSE
* or https://OpenDS.dev.java.net/OpenDS.LICENSE.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at
* trunk/opends/resource/legal-notices/OpenDS.LICENSE. If applicable,
* add the following below this CDDL HEADER, with the fields enclosed
* by brackets "[]" replaced with your own identifying information:
* Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*
* Portions Copyright 2012 Dariusz Janny <dariusz.janny@gmail.com>
* Copyright 2013 ForgeRock AS
*
* 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.opends.server.extensions;
import java.security.MessageDigest;
import java.util.Arrays;
import java.util.Random;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* SHA2-based Unix crypt implementation.
*
* <p>
* Based on the C implementation released into the Public Domain by Ulrich
* Drepper <drepper@redhat.com>
* http://www.akkadia.org/drepper/SHA-crypt.txt
* </p>
*
* <p>
* Conversion to Kotlin and from there to Java in 2012 by Christian Hammers
* <ch@lathspell.de> and likewise put into the Public Domain.
* </p>
*
* <p>
* This class is immutable and thread-safe.
* </p>
*
* <p>
* Note this class was originally in the
* <code>org.apache.commons.codec.digest</code> package, but was moved into
* <code>org.opends.server.extensions</code> for convenience.
* </p>
*
* @version $Id$
* @since 1.7
*/
final class Sha2Crypt {
/**
* Base64 like method to convert binary bytes into ASCII chars.
*
* <p>This class is immutable and thread-safe.</p>
*
* <p>
* Note this class was originally in the
* <code>org.apache.commons.codec.digest</code> package, but was moved into an
* inner class here for convenience. It is <b>not</b> compatible with Base64.
* </p>
*
* @version $Id$
* @since 1.7
*/
static class B64 {
/**
* Table with characters for Base64 transformation.
*/
static final String B64T =
"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
/**
* Base64 like conversion of bytes to ASCII chars.
*
* @param b2
* A byte from the result.
* @param b1
* A byte from the result.
* @param b0
* A byte from the result.
* @param outLen
* The number of expected output chars.
* @param buffer
* Where the output chars is appended to.
*/
static void b64from24bit(byte b2, byte b1, byte b0, int outLen,
StringBuilder buffer) {
// The bit masking is necessary because the JVM byte type is signed!
int w =
((b2 << 16) & 0x00ffffff) | ((b1 << 8) & 0x00ffff) | (b0 & 0xff);
// It's effectively a "for" loop but kept to resemble
// the original C code.
int n = outLen;
while (n-- > 0) {
buffer.append(B64T.charAt(w & 0x3f));
w >>= 6;
}
}
/**
* Generates a string of random chars from the B64T set.
*
* @param num
* Number of chars to generate.
* @return
* a string of random chars from the B64T set
*/
static String getRandomSalt(int num) {
StringBuilder saltString = new StringBuilder();
for (int i = 1; i <= num; i++) {
saltString.append(B64T.charAt(new Random().
nextInt(B64T.length())));
}
return saltString.toString();
}
}
/**
* Default number of rounds if not explicitly specified.
*/
private static final int ROUNDS_DEFAULT = 5000;
/**
* Maximum number of rounds.
*/
private static final int ROUNDS_MAX = 999999999;
/**
* Minimum number of rounds.
*/
private static final int ROUNDS_MIN = 1000;
/**
* Prefix for optional rounds specification.
*/
private static final String ROUNDS_PREFIX = "rounds=";
/**
* The MessageDigest algorithms.
*/
private static final String SHA256_ALGORITHM = "SHA-256";
private static final String SHA512_ALGORITHM = "SHA-512";
/**
* The number of bytes the final hash value will have.
*/
private static final int SHA256_BLOCKSIZE = 32;
private static final int SHA512_BLOCKSIZE = 64;
/**
* The prefixes that can be used to identify this crypt() variant.
*/
static final String SHA256_PREFIX = "$5$";
static final String SHA512_PREFIX = "$6$";
/**
* Returns the magic string denoting the SHA-256 scheme is being used.
*
* @return the magic string
*/
public static String getMagicSHA256Prefix()
{
return SHA256_PREFIX;
}
/**
* Returns the magic string denoting the SHA-512 scheme is being used.
*
* @return the magic string
*/
public static String getMagicSHA512Prefix()
{
return SHA512_PREFIX;
}
/**
* Generates a libc crypt() compatible "$5$" hash value with random salt.
*
* See {@link Crypt#crypt(String, String)} for details.
*
* @param keyBytes
* The plaintext that should be hashed.
* @throws Exception exception
* @return compatible "$5$" hash value with random sal
*/
public static String sha256Crypt(byte[] keyBytes) throws Exception {
return sha256Crypt(keyBytes, null);
}
/**
* Generates a libc6 crypt() compatible "$5$" hash value.
*
* See {@link Crypt#crypt(String, String)} for details.
*
* @param keyBytes
* The plaintext that should be hashed.
* @param salt
* The real salt value without prefix or "rounds=".
* @throws Exception exception
* @return compatible "$5$" hash value
*/
public static String sha256Crypt(byte[] keyBytes, String salt)
throws Exception {
if (salt == null) {
salt = SHA256_PREFIX + B64.getRandomSalt(8);
}
return sha2Crypt(keyBytes, salt, SHA256_PREFIX, SHA256_BLOCKSIZE,
SHA256_ALGORITHM);
}
/**
* Generates a libc6 crypt() compatible "$5$" or "$6$" SHA2 based hash value.
*
* This is a nearly line by line conversion of the original C function. The
* numbered comments are from the algorithm description, the short C-style
* ones from the original C code and the ones with "Remark" from me.
*
* See {@link Crypt#crypt(String, String)} for details.
*
* @param keyBytes
* The plaintext that should be hashed.
* @param salt_string
* The real salt value without prefix or "rounds=".
* @param saltPrefix
* Either $5$ or $6$.
* @param blocksize
* A value that differs between $5$ and $6$.
* @param algorithm
* The MessageDigest algorithm identifier string.
* @throws Exception exception
* @return The complete hash value including prefix and salt.
*/
private static String sha2Crypt(byte[] keyBytes, String salt,
String saltPrefix, int blocksize, String algorithm) throws Exception {
int keyLen = keyBytes.length;
// Extracts effective salt and the number of rounds from the given salt.
int rounds = ROUNDS_DEFAULT;
boolean roundsCustom = false;
if (salt == null) {
throw new IllegalArgumentException("Invalid salt value: null");
}
Pattern p = Pattern
.compile("^\\$([56])\\$(rounds=(\\d+)\\$)?([\\.\\/a-zA-Z0-9]{1,16}).*");
Matcher m = p.matcher(salt);
if (m == null || !m.find()) {
throw new IllegalArgumentException("Invalid salt value: " + salt);
}
if (m.group(3) != null) {
rounds = Integer.parseInt(m.group(3));
rounds = Math.max(ROUNDS_MIN, Math.min(ROUNDS_MAX, rounds));
roundsCustom = true;
}
String saltString = m.group(4);
byte[] saltBytes = saltString.getBytes("UTF-8");
int saltLen = saltBytes.length;
// 1. start digest A
// Prepare for the real work.
MessageDigest ctx = MessageDigest.getInstance(algorithm);
// 2. the password string is added to digest A
/*
* Add the key string.
*/
ctx.update(keyBytes);
// 3. the salt string is added to digest A. This is just the salt string
// itself without the enclosing '$', without the magic salt_prefix $5$ and
// $6$ respectively and without the rounds=<N> specification.
//
// NB: the MD5 algorithm did add the $1$ salt_prefix. This is not deemed
// necessary since it is a constant string and does not add security
// and /possibly/ allows a plain text attack. Since the rounds=<N>
// specification should never be added this would also create an
// inconsistency.
/*
* The last part is the salt string. This must be at most 16 characters and
* it ends at the first `$' character (for compatibility with existing
* implementations).
*/
ctx.update(saltBytes);
// 4. start digest B
/*
* Compute alternate sha512 sum with input KEY, SALT, and KEY. The final
* result will be added to the first context.
*/
MessageDigest altCtx = MessageDigest.getInstance(algorithm);
// 5. add the password to digest B
/*
* Add key.
*/
altCtx.update(keyBytes);
// 6. add the salt string to digest B
/*
* Add salt.
*/
altCtx.update(saltBytes);
// 7. add the password again to digest B
/*
* Add key again.
*/
altCtx.update(keyBytes);
// 8. finish digest B
/*
* Now get result of this (32 bytes) and add it to the other context.
*/
byte[] altResult = altCtx.digest();
// 9. For each block of 32 or 64 bytes in the password string (excluding
// the terminating NUL in the C representation), add digest B to digest A
/*
* Add for any character in the key one byte of the alternate sum.
*/
/*
* (Remark: the C code comment seems wrong for key length > 32!)
*/
int cnt = keyBytes.length;
while (cnt > blocksize) {
ctx.update(altResult, 0, blocksize);
cnt -= blocksize;
}
// 10. For the remaining N bytes of the password string add the first
// N bytes of digest B to digest A
ctx.update(altResult, 0, cnt);
// 11. For each bit of the binary representation of the length of the
// password string up to and including the highest 1-digit, starting
// from to lowest bit position (numeric value 1):
//
// a) for a 1-digit add digest B to digest A
//
// b) for a 0-digit add the password string
//
// NB: this step differs significantly from the MD5 algorithm. It
// adds more randomness.
/*
* Take the binary representation of the length of the key and for every 1
* add the alternate sum, for every 0 the key.
*/
cnt = keyBytes.length;
while (cnt > 0) {
if ((cnt & 1) != 0) {
ctx.update(altResult, 0, blocksize);
} else {
ctx.update(keyBytes);
}
cnt >>= 1;
}
// 12. finish digest A
/*
* Create intermediate result.
*/
altResult = ctx.digest();
// 13. start digest DP
/*
* Start computation of P byte sequence.
*/
altCtx = MessageDigest.getInstance(algorithm);
// 14. for every byte in the password (excluding the terminating NUL byte
// in the C representation of the string)
//
// add the password to digest DP
/*
* For every character in the password add the entire password.
*/
for (int i = 1; i <= keyLen; i++) {
altCtx.update(keyBytes);
}
// 15. finish digest DP
/*
* Finish the digest.
*/
byte[] tempResult = altCtx.digest();
// 16. produce byte sequence P of the same length as the password where
//
// a) for each block of 32 or 64 bytes of length of the password string
// the entire digest DP is used
//
// b) for the remaining N (up to 31 or 63) bytes use the first N
// bytes of digest DP
/*
* Create byte sequence P.
*/
byte[] pBytes = new byte[keyLen];
int cp = 0;
while (cp < keyLen - blocksize) {
System.arraycopy(tempResult, 0, pBytes, cp, blocksize);
cp += blocksize;
}
System.arraycopy(tempResult, 0, pBytes, cp, keyLen - cp);
// 17. start digest DS
/*
* Start computation of S byte sequence.
*/
altCtx = MessageDigest.getInstance(algorithm);
// 18. repeast the following 16+A[0] times, where A[0] represents the first
// byte in digest A interpreted as an 8-bit unsigned value
//
// add the salt to digest DS
/*
* For every character in the password add the entire password.
*/
for (int i = 1; i <= 16 + (altResult[0] & 0xff); i++) {
altCtx.update(saltBytes);
}
// 19. finish digest DS
/*
* Finish the digest.
*/
tempResult = altCtx.digest();
// 20. produce byte sequence S of the same length as the salt string where
//
// a) for each block of 32 or 64 bytes of length of the salt string
// the entire digest DS is used
//
// b) for the remaining N (up to 31 or 63) bytes use the first N
// bytes of digest DS
/*
* Create byte sequence S.
*/
// Remark: The salt is limited to 16 chars, how does this make sense?
byte[] sBytes = new byte[saltLen];
cp = 0;
while (cp < saltLen - blocksize) {
System.arraycopy(tempResult, 0, sBytes, cp, blocksize);
cp += blocksize;
}
System.arraycopy(tempResult, 0, sBytes, cp, saltLen - cp);
// 21. repeat a loop according to the number specified in the rounds=<N>
// specification in the salt (or the default value if none is
// present). Each round is numbered, starting with 0 and up to N-1.
//
// The loop uses a digest as input. In the first round it is the
// digest produced in step 12. In the latter steps it is the digest
// produced in step 21.h. The following text uses the notation
// "digest A/C" to describe this behavior.
/*
* Repeatedly run the collected hash value through sha512 to burn CPU
* cycles.
*/
for (int i = 0; i <= rounds - 1; i++) {
// a) start digest C
/*
* New context.
*/
ctx = MessageDigest.getInstance(algorithm);
// b) for odd round numbers add the byte sequence P to digest C
// c) for even round numbers add digest A/C
/*
* Add key or last result.
*/
if ((i & 1) != 0) {
ctx.update(pBytes, 0, keyLen);
} else {
ctx.update(altResult, 0, blocksize);
}
// d) for all round numbers not divisible by 3 add the byte sequence S
/*
* Add salt for numbers not divisible by 3.
*/
if (i % 3 != 0) {
ctx.update(sBytes, 0, saltLen);
}
// e) for all round numbers not divisible by 7 add the byte sequence P
/*
* Add key for numbers not divisible by 7.
*/
if (i % 7 != 0) {
ctx.update(pBytes, 0, keyLen);
}
// f) for odd round numbers add digest A/C
// g) for even round numbers add the byte sequence P
/*
* Add key or last result.
*/
if ((i & 1) != 0) {
ctx.update(altResult, 0, blocksize);
} else {
ctx.update(pBytes, 0, keyLen);
}
// h) finish digest C.
/*
* Create intermediate result.
*/
altResult = ctx.digest();
}
// 22. Produce the output string. This is an ASCII string of the maximum
// size specified above, consisting of multiple pieces:
//
// a) the salt salt_prefix, $5$ or $6$ respectively
//
// b) the rounds=<N> specification, if one was present in the input
// salt string. A trailing '$' is added in this case to separate
// the rounds specification from the following text.
//
// c) the salt string truncated to 16 characters
//
// d) a '$' character
/*
* Now we can construct the result string. It consists of three parts.
*/
StringBuilder buffer = new StringBuilder(saltPrefix
+ (roundsCustom ? ROUNDS_PREFIX + rounds + "$" : "")
+ saltString + "$");
// e) the base-64 encoded final C digest. The encoding used is as
// follows:
// [...]
//
// Each group of three bytes from the digest produces four
// characters as output:
//
// 1. character: the six low bits of the first byte
// 2. character: the two high bits of the first byte and the
// four low bytes from the second byte
// 3. character: the four high bytes from the second byte and
// the two low bits from the third byte
// 4. character: the six high bits from the third byte
//
// The groups of three bytes are as follows (in this sequence).
// These are the indices into the byte array containing the
// digest, starting with index 0. For the last group there are
// not enough bytes left in the digest and the value zero is used
// in its place. This group also produces only three or two
// characters as output for SHA-512 and SHA-512 respectively.
// This was just a safeguard in the C implementation:
// int buflen = salt_prefix.length() - 1 + ROUNDS_PREFIX.length() + 9 + 1 +
// salt_string.length() + 1 + 86 + 1;
if (blocksize == 32) {
B64.b64from24bit(altResult[0], altResult[10], altResult[20], 4, buffer);
B64.b64from24bit(altResult[21], altResult[1], altResult[11], 4, buffer);
B64.b64from24bit(altResult[12], altResult[22], altResult[2], 4, buffer);
B64.b64from24bit(altResult[3], altResult[13], altResult[23], 4, buffer);
B64.b64from24bit(altResult[24], altResult[4], altResult[14], 4, buffer);
B64.b64from24bit(altResult[15], altResult[25], altResult[5], 4, buffer);
B64.b64from24bit(altResult[6], altResult[16], altResult[26], 4, buffer);
B64.b64from24bit(altResult[27], altResult[7], altResult[17], 4, buffer);
B64.b64from24bit(altResult[18], altResult[28], altResult[8], 4, buffer);
B64.b64from24bit(altResult[9], altResult[19], altResult[29], 4, buffer);
B64.b64from24bit((byte) 0, altResult[31], altResult[30], 3, buffer);
} else {
B64.b64from24bit(altResult[0], altResult[21], altResult[42], 4, buffer);
B64.b64from24bit(altResult[22], altResult[43], altResult[1], 4, buffer);
B64.b64from24bit(altResult[44], altResult[2], altResult[23], 4, buffer);
B64.b64from24bit(altResult[3], altResult[24], altResult[45], 4, buffer);
B64.b64from24bit(altResult[25], altResult[46], altResult[4], 4, buffer);
B64.b64from24bit(altResult[47], altResult[5], altResult[26], 4, buffer);
B64.b64from24bit(altResult[6], altResult[27], altResult[48], 4, buffer);
B64.b64from24bit(altResult[28], altResult[49], altResult[7], 4, buffer);
B64.b64from24bit(altResult[50], altResult[8], altResult[29], 4, buffer);
B64.b64from24bit(altResult[9], altResult[30], altResult[51], 4, buffer);
B64.b64from24bit(altResult[31], altResult[52], altResult[10], 4, buffer);
B64.b64from24bit(altResult[53], altResult[11], altResult[32], 4, buffer);
B64.b64from24bit(altResult[12], altResult[33], altResult[54], 4, buffer);
B64.b64from24bit(altResult[34], altResult[55], altResult[13], 4, buffer);
B64.b64from24bit(altResult[56], altResult[14], altResult[35], 4, buffer);
B64.b64from24bit(altResult[15], altResult[36], altResult[57], 4, buffer);
B64.b64from24bit(altResult[37], altResult[58], altResult[16], 4, buffer);
B64.b64from24bit(altResult[59], altResult[17], altResult[38], 4, buffer);
B64.b64from24bit(altResult[18], altResult[39], altResult[60], 4, buffer);
B64.b64from24bit(altResult[40], altResult[61], altResult[19], 4, buffer);
B64.b64from24bit(altResult[62], altResult[20], altResult[41], 4, buffer);
B64.b64from24bit((byte) 0, (byte) 0, altResult[63], 2, buffer);
}
/*
* Clear the buffer for the intermediate result so that people attaching to
* processes or reading core dumps cannot get any information.
*/
// Is there a better way to do this with the JVM?
Arrays.fill(tempResult, (byte) 0);
Arrays.fill(pBytes, (byte) 0);
Arrays.fill(sBytes, (byte) 0);
ctx.reset();
altCtx.reset();
Arrays.fill(keyBytes, (byte) 0);
Arrays.fill(saltBytes, (byte) 0);
return buffer.toString();
}
/**
* Generates a libc crypt() compatible "$6$" hash value with random salt.
*
* See {@link Crypt#crypt(String, String)} for details.
*
* @param keyBytes
* The plaintext that should be hashed.
* @throws Exception exception
* @return compatible "$6$" hash value with random salt
*/
public static String sha512Crypt(byte[] keyBytes) throws Exception {
return sha512Crypt(keyBytes, null);
}
/**
* Generates a libc6 crypt() compatible "$6$" hash value.
*
* See {@link Crypt#crypt(String, String)} for details.
*
* @param keyBytes
* The plaintext that should be hashed.
* @param salt
* The real salt value without prefix or "rounds=".
* @throws Exception exception
* @return compatible "$6$" hash value
*/
public static String sha512Crypt(byte[] keyBytes, String salt)
throws Exception {
if (salt == null) {
salt = SHA512_PREFIX + B64.getRandomSalt(8);
}
return sha2Crypt(keyBytes, salt, SHA512_PREFIX, SHA512_BLOCKSIZE,
SHA512_ALGORITHM);
}
}