/*
* Copyright (C)2009 - SSHJ Contributors
*
* 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 net.schmizz.sshj.userauth.keyprovider;
import java.io.BufferedReader;
import java.io.EOFException;
import java.io.IOException;
import java.math.BigInteger;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.security.*;
import java.security.spec.*;
import java.util.Arrays;
import javax.xml.bind.DatatypeConverter;
import net.schmizz.sshj.common.Base64;
import net.schmizz.sshj.common.IOUtils;
import net.schmizz.sshj.common.KeyType;
import net.schmizz.sshj.transport.cipher.*;
import net.schmizz.sshj.transport.digest.Digest;
import net.schmizz.sshj.transport.digest.MD5;
/**
* Represents a PKCS5-encoded key file. This is the format typically used by OpenSSH, OpenSSL, Amazon, etc.
*/
public class PKCS5KeyFile extends BaseFileKeyProvider {
public static class Factory
implements net.schmizz.sshj.common.Factory.Named<FileKeyProvider> {
@Override
public FileKeyProvider create() {
return new PKCS5KeyFile();
}
@Override
public String getName() {
return "PKCS5";
}
}
/**
* Indicates a format issue with PKCS5 data
*/
public static class FormatException
extends IOException {
FormatException(String msg) {
super(msg);
}
}
/**
* Indicates a problem decrypting the data
*/
public static class DecryptException
extends IOException {
DecryptException(String msg) {
super(msg);
}
}
protected byte[] data;
protected KeyPair readKeyPair()
throws IOException {
BufferedReader reader = new BufferedReader(resource.getReader());
try {
String line = null;
Cipher cipher = new NoneCipher();
StringBuffer sb = new StringBuffer();
byte[] iv = new byte[0]; // salt
while ((line = reader.readLine()) != null) {
if (line.startsWith("-----BEGIN ") && line.endsWith(" PRIVATE KEY-----")) {
int end = line.length() - 17;
if (end > 11) {
String s = line.substring(11, line.length() - 17);
if ("RSA".equals(s)) {
type = KeyType.RSA;
} else if ("DSA".equals(s)) {
type = KeyType.DSA;
} else if ("DSS".equals(s)) {
type = KeyType.DSA;
} else {
throw new FormatException("Unrecognized PKCS5 key type: " + s);
}
} else {
throw new FormatException("Bad header; possibly PKCS8 format?");
}
} else if (line.startsWith("-----END")) {
break;
} else if (type != null) {
if (line.startsWith("Proc-Type: ")) {
if (!"4,ENCRYPTED".equals(line.substring(11))) {
throw new FormatException("Unrecognized Proc-Type: " + line.substring(11));
}
} else if (line.startsWith("DEK-Info: ")) {
int ptr = line.indexOf(",");
if (ptr == -1) {
throw new FormatException("Unrecognized DEK-Info: " + line.substring(10));
} else {
String algorithm = line.substring(10, ptr);
if ("DES-EDE3-CBC".equals(algorithm)) {
cipher = new TripleDESCBC();
} else if ("AES-128-CBC".equals(algorithm)) {
cipher = new AES128CBC();
} else if ("AES-192-CBC".equals(algorithm)) {
cipher = new AES192CBC();
} else if ("AES-256-CBC".equals(algorithm)) {
cipher = new AES256CBC();
} else {
throw new FormatException("Not a supported algorithm: " + algorithm);
}
iv = Arrays.copyOfRange(DatatypeConverter.parseHexBinary(line.substring(ptr + 1)), 0, cipher.getIVSize());
}
} else if (line.length() > 0) {
sb.append(line);
}
}
}
if (type == null) {
throw new FormatException("PKCS5 header not found");
}
ASN1Data asn = new ASN1Data(data = decrypt(Base64.decode(sb.toString()), cipher, iv));
switch (type) {
case RSA: {
KeyFactory factory = KeyFactory.getInstance("RSA");
asn.readNext();
BigInteger modulus = asn.readNext();
BigInteger pubExp = asn.readNext();
BigInteger prvExp = asn.readNext();
PublicKey pubKey = factory.generatePublic(new RSAPublicKeySpec(modulus, pubExp));
PrivateKey prvKey = factory.generatePrivate(new RSAPrivateKeySpec(modulus, prvExp));
return new KeyPair(pubKey, prvKey);
}
case DSA: {
KeyFactory factory = KeyFactory.getInstance("DSA");
asn.readNext();
BigInteger p = asn.readNext();
BigInteger q = asn.readNext();
BigInteger g = asn.readNext();
BigInteger pub = asn.readNext();
BigInteger prv = asn.readNext();
PublicKey pubKey = factory.generatePublic(new DSAPublicKeySpec(pub, p, q, g));
PrivateKey prvKey = factory.generatePrivate(new DSAPrivateKeySpec(prv, p, q, g));
return new KeyPair(pubKey, prvKey);
}
default:
throw new IOException("Unrecognized PKCS5 key type: " + type);
}
} catch (NoSuchAlgorithmException e) {
throw new IOException(e);
} catch (InvalidKeySpecException e) {
throw new IOException(e);
} finally {
reader.close();
}
}
@Override
public String toString() {
return "PKCS5KeyFile{resource=" + resource + "}";
}
private byte[] getPassphraseBytes() {
CharBuffer cb = CharBuffer.wrap(pwdf.reqPassword(resource));
ByteBuffer bb = IOUtils.UTF8.encode(cb);
byte[] result = Arrays.copyOfRange(bb.array(), bb.position(), bb.limit());
Arrays.fill(cb.array(), '\u0000');
Arrays.fill(bb.array(), (byte) 0);
return result;
}
private byte[] decrypt(byte[] raw, Cipher cipher, byte[] iv) throws DecryptException {
if (pwdf == null) {
return raw;
}
Digest md5 = new MD5();
int bsize = cipher.getBlockSize();
int hsize = md5.getBlockSize();
int hnlen = bsize / hsize * hsize + (bsize % hsize == 0 ? 0 : hsize);
do {
md5.init();
byte[] hn = new byte[hnlen];
byte[] tmp = null;
byte[] passphrase = getPassphraseBytes();
for (int i = 0; i + hsize <= hn.length; ) {
if (tmp != null) {
md5.update(tmp, 0, tmp.length);
}
md5.update(passphrase, 0, passphrase.length);
md5.update(iv, 0, iv.length > 8 ? 8 : iv.length);
tmp = md5.digest();
System.arraycopy(tmp, 0, hn, i, tmp.length);
i += tmp.length;
}
Arrays.fill(passphrase, (byte) 0);
byte[] key = Arrays.copyOfRange(hn, 0, bsize);
cipher.init(Cipher.Mode.Decrypt, key, iv);
Arrays.fill(key, (byte) 0);
byte[] decrypted = Arrays.copyOf(raw, raw.length);
cipher.update(decrypted, 0, decrypted.length);
if (ASN1Data.MAGIC == decrypted[0]) {
return decrypted;
}
} while (pwdf.shouldRetry(resource));
throw new DecryptException("Decryption failed");
}
class ASN1Data {
static final byte MAGIC = (byte) 0x30;
private byte[] buff;
private int index, length;
ASN1Data(byte[] buff) throws FormatException {
this.buff = buff;
index = 0;
if (buff[index++] != MAGIC) {
throw new FormatException("Not ASN.1 data");
}
length = buff[index++] & 0xff;
if ((length & 0x80) != 0) {
int counter = length & 0x7f;
length = 0;
while (counter-- > 0) {
length = (length << 8) + (buff[index++] & 0xff);
}
}
if ((index + length) > buff.length) {
throw new FormatException("Length mismatch: " + buff.length + " != " + (index + length));
}
}
BigInteger readNext() throws IOException {
if (index >= length) {
throw new EOFException();
} else if (buff[index++] != 0x02) {
throw new IOException("Not an int code: " + Integer.toHexString(0xff & buff[index]));
}
int length = buff[index++] & 0xff;
if ((length & 0x80) != 0) {
int counter = length & 0x7f;
length = 0;
while (counter-- > 0) {
length = (length << 8) + (buff[index++] & 0xff);
}
}
byte[] sequence = new byte[length];
System.arraycopy(buff, index, sequence, 0, length);
index += length;
return new BigInteger(sequence);
}
}
}