src/main/java/ch/ethz/ssh2/crypto/PEMDecoder.java - platform/external/ganymed-ssh2 - Git at Google

 /*
  * Copyright (c) 2006-2011 Christian Plattner. All rights reserved.
  * Please refer to the LICENSE.txt for licensing details.
  */
 package ch.ethz.ssh2.crypto;

 import java.io.BufferedReader;
 import java.io.CharArrayReader;
 import java.io.IOException;
 import java.math.BigInteger;

 import ch.ethz.ssh2.crypto.cipher.AES;
 import ch.ethz.ssh2.crypto.cipher.BlockCipher;
 import ch.ethz.ssh2.crypto.cipher.CBCMode;
 import ch.ethz.ssh2.crypto.cipher.DES;
 import ch.ethz.ssh2.crypto.cipher.DESede;
 import ch.ethz.ssh2.crypto.digest.MD5;
 import ch.ethz.ssh2.signature.DSAPrivateKey;
 import ch.ethz.ssh2.signature.RSAPrivateKey;
 import ch.ethz.ssh2.util.StringEncoder;

 /**
  * PEM Support.
  *
  * @author Christian Plattner
  * @version $Id: PEMDecoder.java 37 2011-05-28 22:31:46Z dkocher@sudo.ch $
  */
 public class PEMDecoder
 {
 	private static final int PEM_RSA_PRIVATE_KEY = 1;
 	private static final int PEM_DSA_PRIVATE_KEY = 2;

 	private static int hexToInt(char c)
 	{
 		if ((c >= 'a') && (c <= 'f'))
 		{
 			return (c - 'a') + 10;
 		}

 		if ((c >= 'A') && (c <= 'F'))
 		{
 			return (c - 'A') + 10;
 		}

 		if ((c >= '0') && (c <= '9'))
 		{
 			return (c - '0');
 		}

 		throw new IllegalArgumentException("Need hex char");
 	}

 	private static byte[] hexToByteArray(String hex)
 	{
 		if (hex == null)
 			throw new IllegalArgumentException("null argument");

 		if ((hex.length() % 2) != 0)
 			throw new IllegalArgumentException("Uneven string length in hex encoding.");

 		byte decoded[] = new byte[hex.length() / 2];

 		for (int i = 0; i < decoded.length; i++)
 		{
 			int hi = hexToInt(hex.charAt(i * 2));
 			int lo = hexToInt(hex.charAt((i * 2) + 1));

 			decoded[i] = (byte) (hi * 16 + lo);
 		}

 		return decoded;
 	}

 	private static byte[] generateKeyFromPasswordSaltWithMD5(byte[] password, byte[] salt, int keyLen)
 			throws IOException
 	{
 		if (salt.length < 8)
 			throw new IllegalArgumentException("Salt needs to be at least 8 bytes for key generation.");

 		MD5 md5 = new MD5();

 		byte[] key = new byte[keyLen];
 		byte[] tmp = new byte[md5.getDigestLength()];

 		while (true)
 		{
 			md5.update(password, 0, password.length);
 			md5.update(salt, 0, 8); // ARGH we only use the first 8 bytes of the salt in this step.
 			// This took me two hours until I got AES-xxx running.

 			int copy = (keyLen < tmp.length) ? keyLen : tmp.length;

 			md5.digest(tmp, 0);

 			System.arraycopy(tmp, 0, key, key.length - keyLen, copy);

 			keyLen -= copy;

 			if (keyLen == 0)
 				return key;

 			md5.update(tmp, 0, tmp.length);
 		}
 	}

 	private static byte[] removePadding(byte[] buff, int blockSize) throws IOException
 	{
 		/* Removes RFC 1423/PKCS #7 padding */

 		int rfc_1423_padding = buff[buff.length - 1] & 0xff;

 		if ((rfc_1423_padding < 1) || (rfc_1423_padding > blockSize))
 			throw new PEMDecryptException("Decrypted PEM has wrong padding, did you specify the correct password?");

 		for (int i = 2; i <= rfc_1423_padding; i++)
 		{
 			if (buff[buff.length - i] != rfc_1423_padding)
 				throw new PEMDecryptException("Decrypted PEM has wrong padding, did you specify the correct password?");
 		}

 		byte[] tmp = new byte[buff.length - rfc_1423_padding];
 		System.arraycopy(buff, 0, tmp, 0, buff.length - rfc_1423_padding);
 		return tmp;
 	}

 	private static PEMStructure parsePEM(char[] pem) throws IOException
 	{
 		PEMStructure ps = new PEMStructure();

 		String line = null;

 		BufferedReader br = new BufferedReader(new CharArrayReader(pem));

 		String endLine = null;

 		while (true)
 		{
 			line = br.readLine();

 			if (line == null)
 				throw new IOException("Invalid PEM structure, '-----BEGIN...' missing");

 			line = line.trim();

 			if (line.startsWith("-----BEGIN DSA PRIVATE KEY-----"))
 			{
 				endLine = "-----END DSA PRIVATE KEY-----";
 				ps.pemType = PEM_DSA_PRIVATE_KEY;
 				break;
 			}

 			if (line.startsWith("-----BEGIN RSA PRIVATE KEY-----"))
 			{
 				endLine = "-----END RSA PRIVATE KEY-----";
 				ps.pemType = PEM_RSA_PRIVATE_KEY;
 				break;
 			}
 		}

 		while (true)
 		{
 			line = br.readLine();

 			if (line == null)
 				throw new IOException("Invalid PEM structure, " + endLine + " missing");

 			line = line.trim();

 			int sem_idx = line.indexOf(':');

 			if (sem_idx == -1)
 				break;

 			String name = line.substring(0, sem_idx + 1);
 			String value = line.substring(sem_idx + 1);

 			String values[] = value.split(",");

 			for (int i = 0; i < values.length; i++)
 				values[i] = values[i].trim();

 			// Proc-Type: 4,ENCRYPTED
 			// DEK-Info: DES-EDE3-CBC,579B6BE3E5C60483

 			if ("Proc-Type:".equals(name))
 			{
 				ps.procType = values;
 				continue;
 			}

 			if ("DEK-Info:".equals(name))
 			{
 				ps.dekInfo = values;
 				continue;
 			}
 			/* Ignore line */
 		}

 		StringBuilder keyData = new StringBuilder();

 		while (true)
 		{
 			if (line == null)
 				throw new IOException("Invalid PEM structure, " + endLine + " missing");

 			line = line.trim();

 			if (line.startsWith(endLine))
 				break;

 			keyData.append(line);

 			line = br.readLine();
 		}

 		char[] pem_chars = new char[keyData.length()];
 		keyData.getChars(0, pem_chars.length, pem_chars, 0);

 		ps.data = Base64.decode(pem_chars);

 		if (ps.data.length == 0)
 			throw new IOException("Invalid PEM structure, no data available");

 		return ps;
 	}

 	private static void decryptPEM(PEMStructure ps, byte[] pw) throws IOException
 	{
 		if (ps.dekInfo == null)
 			throw new IOException("Broken PEM, no mode and salt given, but encryption enabled");

 		if (ps.dekInfo.length != 2)
 			throw new IOException("Broken PEM, DEK-Info is incomplete!");

 		String algo = ps.dekInfo[0];
 		byte[] salt = hexToByteArray(ps.dekInfo[1]);

 		BlockCipher bc = null;

 		if (algo.equals("DES-EDE3-CBC"))
 		{
 			DESede des3 = new DESede();
 			des3.init(false, generateKeyFromPasswordSaltWithMD5(pw, salt, 24));
 			bc = new CBCMode(des3, salt, false);
 		}
 		else if (algo.equals("DES-CBC"))
 		{
 			DES des = new DES();
 			des.init(false, generateKeyFromPasswordSaltWithMD5(pw, salt, 8));
 			bc = new CBCMode(des, salt, false);
 		}
 		else if (algo.equals("AES-128-CBC"))
 		{
 			AES aes = new AES();
 			aes.init(false, generateKeyFromPasswordSaltWithMD5(pw, salt, 16));
 			bc = new CBCMode(aes, salt, false);
 		}
 		else if (algo.equals("AES-192-CBC"))
 		{
 			AES aes = new AES();
 			aes.init(false, generateKeyFromPasswordSaltWithMD5(pw, salt, 24));
 			bc = new CBCMode(aes, salt, false);
 		}
 		else if (algo.equals("AES-256-CBC"))
 		{
 			AES aes = new AES();
 			aes.init(false, generateKeyFromPasswordSaltWithMD5(pw, salt, 32));
 			bc = new CBCMode(aes, salt, false);
 		}
 		else
 		{
 			throw new IOException("Cannot decrypt PEM structure, unknown cipher " + algo);
 		}

 		if ((ps.data.length % bc.getBlockSize()) != 0)
 			throw new IOException("Invalid PEM structure, size of encrypted block is not a multiple of "
 					+ bc.getBlockSize());

 		/* Now decrypt the content */

 		byte[] dz = new byte[ps.data.length];

 		for (int i = 0; i < ps.data.length / bc.getBlockSize(); i++)
 		{
 			bc.transformBlock(ps.data, i * bc.getBlockSize(), dz, i * bc.getBlockSize());
 		}

 		/* Now check and remove RFC 1423/PKCS #7 padding */

 		dz = removePadding(dz, bc.getBlockSize());

 		ps.data = dz;
 		ps.dekInfo = null;
 		ps.procType = null;
 	}

 	public static final boolean isPEMEncrypted(PEMStructure ps) throws IOException
 	{
 		if (ps.procType == null)
 			return false;

 		if (ps.procType.length != 2)
 			throw new IOException("Unknown Proc-Type field.");

 		if ("4".equals(ps.procType[0]) == false)
 			throw new IOException("Unknown Proc-Type field (" + ps.procType[0] + ")");

 		if ("ENCRYPTED".equals(ps.procType[1]))
 			return true;

 		return false;
 	}

 	public static final boolean isPEMEncrypted(char[] pem) throws IOException
 	{
 		return isPEMEncrypted(parsePEM(pem));
 	}

 	public static Object decode(char[] pem, String password) throws IOException
 	{
 		PEMStructure ps = parsePEM(pem);

 		if (isPEMEncrypted(ps))
 		{
 			if (password == null)
 				throw new IOException("PEM is encrypted, but no password was specified");

 			decryptPEM(ps, StringEncoder.GetBytes(password));
 		}

 		if (ps.pemType == PEM_DSA_PRIVATE_KEY)
 		{
 			SimpleDERReader dr = new SimpleDERReader(ps.data);

 			byte[] seq = dr.readSequenceAsByteArray();

 			if (dr.available() != 0)
 				throw new IOException("Padding in DSA PRIVATE KEY DER stream.");

 			dr.resetInput(seq);

 			BigInteger version = dr.readInt();

 			if (version.compareTo(BigInteger.ZERO) != 0)
 				throw new IOException("Wrong version (" + version + ") in DSA PRIVATE KEY DER stream.");

 			BigInteger p = dr.readInt();
 			BigInteger q = dr.readInt();
 			BigInteger g = dr.readInt();
 			BigInteger y = dr.readInt();
 			BigInteger x = dr.readInt();

 			if (dr.available() != 0)
 				throw new IOException("Padding in DSA PRIVATE KEY DER stream.");

 			return new DSAPrivateKey(p, q, g, y, x);
 		}

 		if (ps.pemType == PEM_RSA_PRIVATE_KEY)
 		{
 			SimpleDERReader dr = new SimpleDERReader(ps.data);

 			byte[] seq = dr.readSequenceAsByteArray();

 			if (dr.available() != 0)
 				throw new IOException("Padding in RSA PRIVATE KEY DER stream.");

 			dr.resetInput(seq);

 			BigInteger version = dr.readInt();

 			if ((version.compareTo(BigInteger.ZERO) != 0) && (version.compareTo(BigInteger.ONE) != 0))
 				throw new IOException("Wrong version (" + version + ") in RSA PRIVATE KEY DER stream.");

 			BigInteger n = dr.readInt();
 			BigInteger e = dr.readInt();
 			BigInteger d = dr.readInt();

 			return new RSAPrivateKey(d, e, n);
 		}

 		throw new IOException("PEM problem: it is of unknown type");
 	}

 }
	/*
	* Copyright (c) 2006-2011 Christian Plattner. All rights reserved.
	* Please refer to the LICENSE.txt for licensing details.
	*/
	package ch.ethz.ssh2.crypto;

	import java.io.BufferedReader;
	import java.io.CharArrayReader;
	import java.io.IOException;
	import java.math.BigInteger;

	import ch.ethz.ssh2.crypto.cipher.AES;
	import ch.ethz.ssh2.crypto.cipher.BlockCipher;
	import ch.ethz.ssh2.crypto.cipher.CBCMode;
	import ch.ethz.ssh2.crypto.cipher.DES;
	import ch.ethz.ssh2.crypto.cipher.DESede;
	import ch.ethz.ssh2.crypto.digest.MD5;
	import ch.ethz.ssh2.signature.DSAPrivateKey;
	import ch.ethz.ssh2.signature.RSAPrivateKey;
	import ch.ethz.ssh2.util.StringEncoder;

	/**
	* PEM Support.
	*
	* @author Christian Plattner
	* @version $Id: PEMDecoder.java 37 2011-05-28 22:31:46Z dkocher@sudo.ch $
	*/
	public class PEMDecoder
	{
	private static final int PEM_RSA_PRIVATE_KEY = 1;
	private static final int PEM_DSA_PRIVATE_KEY = 2;

	private static int hexToInt(char c)
	{
	if ((c >= 'a') && (c <= 'f'))
	{
	return (c - 'a') + 10;
	}

	if ((c >= 'A') && (c <= 'F'))
	{
	return (c - 'A') + 10;
	}

	if ((c >= '0') && (c <= '9'))
	{
	return (c - '0');
	}

	throw new IllegalArgumentException("Need hex char");
	}

	private static byte[] hexToByteArray(String hex)
	{
	if (hex == null)
	throw new IllegalArgumentException("null argument");

	if ((hex.length() % 2) != 0)
	throw new IllegalArgumentException("Uneven string length in hex encoding.");

	byte decoded[] = new byte[hex.length() / 2];

	for (int i = 0; i < decoded.length; i++)
	{
	int hi = hexToInt(hex.charAt(i * 2));
	int lo = hexToInt(hex.charAt((i * 2) + 1));

	decoded[i] = (byte) (hi * 16 + lo);
	}

	return decoded;
	}

	private static byte[] generateKeyFromPasswordSaltWithMD5(byte[] password, byte[] salt, int keyLen)
	throws IOException
	{
	if (salt.length < 8)
	throw new IllegalArgumentException("Salt needs to be at least 8 bytes for key generation.");

	MD5 md5 = new MD5();

	byte[] key = new byte[keyLen];
	byte[] tmp = new byte[md5.getDigestLength()];

	while (true)
	{
	md5.update(password, 0, password.length);
	md5.update(salt, 0, 8); // ARGH we only use the first 8 bytes of the salt in this step.
	// This took me two hours until I got AES-xxx running.

	int copy = (keyLen < tmp.length) ? keyLen : tmp.length;

	md5.digest(tmp, 0);

	System.arraycopy(tmp, 0, key, key.length - keyLen, copy);

	keyLen -= copy;

	if (keyLen == 0)
	return key;

	md5.update(tmp, 0, tmp.length);
	}
	}

	private static byte[] removePadding(byte[] buff, int blockSize) throws IOException
	{
	/* Removes RFC 1423/PKCS #7 padding */

	int rfc_1423_padding = buff[buff.length - 1] & 0xff;

	if ((rfc_1423_padding < 1) \|\| (rfc_1423_padding > blockSize))
	throw new PEMDecryptException("Decrypted PEM has wrong padding, did you specify the correct password?");

	for (int i = 2; i <= rfc_1423_padding; i++)
	{
	if (buff[buff.length - i] != rfc_1423_padding)
	throw new PEMDecryptException("Decrypted PEM has wrong padding, did you specify the correct password?");
	}

	byte[] tmp = new byte[buff.length - rfc_1423_padding];
	System.arraycopy(buff, 0, tmp, 0, buff.length - rfc_1423_padding);
	return tmp;
	}

	private static PEMStructure parsePEM(char[] pem) throws IOException
	{
	PEMStructure ps = new PEMStructure();

	String line = null;

	BufferedReader br = new BufferedReader(new CharArrayReader(pem));

	String endLine = null;

	while (true)
	{
	line = br.readLine();

	if (line == null)
	throw new IOException("Invalid PEM structure, '-----BEGIN...' missing");

	line = line.trim();

	if (line.startsWith("-----BEGIN DSA PRIVATE KEY-----"))
	{
	endLine = "-----END DSA PRIVATE KEY-----";
	ps.pemType = PEM_DSA_PRIVATE_KEY;
	break;
	}

	if (line.startsWith("-----BEGIN RSA PRIVATE KEY-----"))
	{
	endLine = "-----END RSA PRIVATE KEY-----";
	ps.pemType = PEM_RSA_PRIVATE_KEY;
	break;
	}
	}

	while (true)
	{
	line = br.readLine();

	if (line == null)
	throw new IOException("Invalid PEM structure, " + endLine + " missing");

	line = line.trim();

	int sem_idx = line.indexOf(':');

	if (sem_idx == -1)
	break;

	String name = line.substring(0, sem_idx + 1);
	String value = line.substring(sem_idx + 1);

	String values[] = value.split(",");

	for (int i = 0; i < values.length; i++)
	values[i] = values[i].trim();

	// Proc-Type: 4,ENCRYPTED
	// DEK-Info: DES-EDE3-CBC,579B6BE3E5C60483

	if ("Proc-Type:".equals(name))
	{
	ps.procType = values;
	continue;
	}

	if ("DEK-Info:".equals(name))
	{
	ps.dekInfo = values;
	continue;
	}
	/* Ignore line */
	}

	StringBuilder keyData = new StringBuilder();

	while (true)
	{
	if (line == null)
	throw new IOException("Invalid PEM structure, " + endLine + " missing");

	line = line.trim();

	if (line.startsWith(endLine))
	break;

	keyData.append(line);

	line = br.readLine();
	}

	char[] pem_chars = new char[keyData.length()];
	keyData.getChars(0, pem_chars.length, pem_chars, 0);

	ps.data = Base64.decode(pem_chars);

	if (ps.data.length == 0)
	throw new IOException("Invalid PEM structure, no data available");

	return ps;
	}

	private static void decryptPEM(PEMStructure ps, byte[] pw) throws IOException
	{
	if (ps.dekInfo == null)
	throw new IOException("Broken PEM, no mode and salt given, but encryption enabled");

	if (ps.dekInfo.length != 2)
	throw new IOException("Broken PEM, DEK-Info is incomplete!");

	String algo = ps.dekInfo[0];
	byte[] salt = hexToByteArray(ps.dekInfo[1]);

	BlockCipher bc = null;

	if (algo.equals("DES-EDE3-CBC"))
	{
	DESede des3 = new DESede();
	des3.init(false, generateKeyFromPasswordSaltWithMD5(pw, salt, 24));
	bc = new CBCMode(des3, salt, false);
	}
	else if (algo.equals("DES-CBC"))
	{
	DES des = new DES();
	des.init(false, generateKeyFromPasswordSaltWithMD5(pw, salt, 8));
	bc = new CBCMode(des, salt, false);
	}
	else if (algo.equals("AES-128-CBC"))
	{
	AES aes = new AES();
	aes.init(false, generateKeyFromPasswordSaltWithMD5(pw, salt, 16));
	bc = new CBCMode(aes, salt, false);
	}
	else if (algo.equals("AES-192-CBC"))
	{
	AES aes = new AES();
	aes.init(false, generateKeyFromPasswordSaltWithMD5(pw, salt, 24));
	bc = new CBCMode(aes, salt, false);
	}
	else if (algo.equals("AES-256-CBC"))
	{
	AES aes = new AES();
	aes.init(false, generateKeyFromPasswordSaltWithMD5(pw, salt, 32));
	bc = new CBCMode(aes, salt, false);
	}
	else
	{
	throw new IOException("Cannot decrypt PEM structure, unknown cipher " + algo);
	}

	if ((ps.data.length % bc.getBlockSize()) != 0)
	throw new IOException("Invalid PEM structure, size of encrypted block is not a multiple of "
	+ bc.getBlockSize());

	/* Now decrypt the content */

	byte[] dz = new byte[ps.data.length];

	for (int i = 0; i < ps.data.length / bc.getBlockSize(); i++)
	{
	bc.transformBlock(ps.data, i * bc.getBlockSize(), dz, i * bc.getBlockSize());
	}

	/* Now check and remove RFC 1423/PKCS #7 padding */

	dz = removePadding(dz, bc.getBlockSize());

	ps.data = dz;
	ps.dekInfo = null;
	ps.procType = null;
	}

	public static final boolean isPEMEncrypted(PEMStructure ps) throws IOException
	{
	if (ps.procType == null)
	return false;

	if (ps.procType.length != 2)
	throw new IOException("Unknown Proc-Type field.");

	if ("4".equals(ps.procType[0]) == false)
	throw new IOException("Unknown Proc-Type field (" + ps.procType[0] + ")");

	if ("ENCRYPTED".equals(ps.procType[1]))
	return true;

	return false;
	}

	public static final boolean isPEMEncrypted(char[] pem) throws IOException
	{
	return isPEMEncrypted(parsePEM(pem));
	}

	public static Object decode(char[] pem, String password) throws IOException
	{
	PEMStructure ps = parsePEM(pem);

	if (isPEMEncrypted(ps))
	{
	if (password == null)
	throw new IOException("PEM is encrypted, but no password was specified");

	decryptPEM(ps, StringEncoder.GetBytes(password));
	}

	if (ps.pemType == PEM_DSA_PRIVATE_KEY)
	{
	SimpleDERReader dr = new SimpleDERReader(ps.data);

	byte[] seq = dr.readSequenceAsByteArray();

	if (dr.available() != 0)
	throw new IOException("Padding in DSA PRIVATE KEY DER stream.");

	dr.resetInput(seq);

	BigInteger version = dr.readInt();

	if (version.compareTo(BigInteger.ZERO) != 0)
	throw new IOException("Wrong version (" + version + ") in DSA PRIVATE KEY DER stream.");

	BigInteger p = dr.readInt();
	BigInteger q = dr.readInt();
	BigInteger g = dr.readInt();
	BigInteger y = dr.readInt();
	BigInteger x = dr.readInt();

	if (dr.available() != 0)
	throw new IOException("Padding in DSA PRIVATE KEY DER stream.");

	return new DSAPrivateKey(p, q, g, y, x);
	}

	if (ps.pemType == PEM_RSA_PRIVATE_KEY)
	{
	SimpleDERReader dr = new SimpleDERReader(ps.data);

	byte[] seq = dr.readSequenceAsByteArray();

	if (dr.available() != 0)
	throw new IOException("Padding in RSA PRIVATE KEY DER stream.");

	dr.resetInput(seq);

	BigInteger version = dr.readInt();

	if ((version.compareTo(BigInteger.ZERO) != 0) && (version.compareTo(BigInteger.ONE) != 0))
	throw new IOException("Wrong version (" + version + ") in RSA PRIVATE KEY DER stream.");

	BigInteger n = dr.readInt();
	BigInteger e = dr.readInt();
	BigInteger d = dr.readInt();

	return new RSAPrivateKey(d, e, n);
	}

	throw new IOException("PEM problem: it is of unknown type");
	}

	}