From ad9b24675b3b582ea4e6bbe6ee1fce9dee37f1f3 Mon Sep 17 00:00:00 2001 From: Kenny Root Date: Sat, 17 Nov 2007 05:58:42 +0000 Subject: Initial import. --- .../java/com/trilead/ssh2/crypto/PEMDecoder.java | 377 +++++++++++++++++++++ 1 file changed, 377 insertions(+) create mode 100644 lib/src/main/java/com/trilead/ssh2/crypto/PEMDecoder.java (limited to 'lib/src/main/java/com/trilead/ssh2/crypto/PEMDecoder.java') diff --git a/lib/src/main/java/com/trilead/ssh2/crypto/PEMDecoder.java b/lib/src/main/java/com/trilead/ssh2/crypto/PEMDecoder.java new file mode 100644 index 0000000..c6f1a4e --- /dev/null +++ b/lib/src/main/java/com/trilead/ssh2/crypto/PEMDecoder.java @@ -0,0 +1,377 @@ + +package com.trilead.ssh2.crypto; + +import java.io.BufferedReader; +import java.io.CharArrayReader; +import java.io.IOException; +import java.math.BigInteger; + +import com.trilead.ssh2.crypto.cipher.AES; +import com.trilead.ssh2.crypto.cipher.BlockCipher; +import com.trilead.ssh2.crypto.cipher.CBCMode; +import com.trilead.ssh2.crypto.cipher.DES; +import com.trilead.ssh2.crypto.cipher.DESede; +import com.trilead.ssh2.crypto.digest.MD5; +import com.trilead.ssh2.signature.DSAPrivateKey; +import com.trilead.ssh2.signature.RSAPrivateKey; + + +/** + * PEM Support. + * + * @author Christian Plattner, plattner@trilead.com + * @version $Id: PEMDecoder.java,v 1.1 2007/10/15 12:49:56 cplattne Exp $ + */ +public class PEMDecoder +{ + private static final int PEM_RSA_PRIVATE_KEY = 1; + private static final int PEM_DSA_PRIVATE_KEY = 2; + + private static final 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 IOException("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 IOException("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 final 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 */ + } + + StringBuffer keyData = new StringBuffer(); + + 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 final 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 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, password.getBytes()); + } + + 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"); + } + +} -- cgit v1.2.3