/* -*-mode:java; c-basic-offset:2; indent-tabs-mode:nil -*- */
/*
Copyright (c) 2013-2014 ymnk, JCraft,Inc. All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

  1. Redistributions of source code must retain the above copyright notice,
     this list of conditions and the following disclaimer.

  2. Redistributions in binary form must reproduce the above copyright 
     notice, this list of conditions and the following disclaimer in 
     the documentation and/or other materials provided with the distribution.

  3. The names of the authors may not be used to endorse or promote products
     derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JCRAFT,
INC. OR ANY CONTRIBUTORS TO THIS SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

package com.jcraft.jsch;

import java.util.Vector;
import java.math.BigInteger;

public class KeyPairPKCS8 extends KeyPair {
  private static final byte[] rsaEncryption = {
    (byte)0x2a, (byte)0x86, (byte)0x48, (byte)0x86,
    (byte)0xf7, (byte)0x0d, (byte)0x01, (byte)0x01, (byte)0x01
  };

  private static final byte[] dsaEncryption = {
    (byte)0x2a, (byte)0x86, (byte)0x48, (byte)0xce,
    (byte)0x38, (byte)0x04, (byte)0x1
  };

  private static final byte[] pbes2 = {
    (byte)0x2a, (byte)0x86, (byte)0x48, (byte)0x86, (byte)0xf7,
    (byte)0x0d, (byte)0x01, (byte)0x05, (byte)0x0d 
  };

  private static final byte[] pbkdf2 = {
    (byte)0x2a, (byte)0x86, (byte)0x48, (byte)0x86, (byte)0xf7,
    (byte)0x0d, (byte)0x01, (byte)0x05, (byte)0x0c 
  };

  private static final byte[] aes128cbc = {
    (byte)0x60, (byte)0x86, (byte)0x48, (byte)0x01, (byte)0x65,
    (byte)0x03, (byte)0x04, (byte)0x01, (byte)0x02 
  };

  private static final byte[] aes192cbc = {
    (byte)0x60, (byte)0x86, (byte)0x48, (byte)0x01, (byte)0x65,
    (byte)0x03, (byte)0x04, (byte)0x01, (byte)0x16 
  };

  private static final byte[] aes256cbc = {
    (byte)0x60, (byte)0x86, (byte)0x48, (byte)0x01, (byte)0x65,
    (byte)0x03, (byte)0x04, (byte)0x01, (byte)0x2a 
  };

  private static final byte[] pbeWithMD5AndDESCBC = {
    (byte)0x2a, (byte)0x86, (byte)0x48, (byte)0x86, (byte)0xf7,
    (byte)0x0d, (byte)0x01, (byte)0x05, (byte)0x03
  };

  private KeyPair kpair = null;

  public KeyPairPKCS8(JSch jsch){
    super(jsch);
  }

  void generate(int key_size) throws JSchException{
  }

  private static final byte[] begin=Util.str2byte("-----BEGIN DSA PRIVATE KEY-----");
  private static final byte[] end=Util.str2byte("-----END DSA PRIVATE KEY-----");

  byte[] getBegin(){ return begin; }
  byte[] getEnd(){ return end; }

  byte[] getPrivateKey(){
    return null;
  }

  boolean parse(byte[] plain){

    /* from RFC5208
      PrivateKeyInfo ::= SEQUENCE {
        version                   Version,
        privateKeyAlgorithm       PrivateKeyAlgorithmIdentifier,
        privateKey                PrivateKey,
        attributes           [0]  IMPLICIT Attributes OPTIONAL 
      }
      Version ::= INTEGER
      PrivateKeyAlgorithmIdentifier ::= AlgorithmIdentifier
      PrivateKey ::= OCTET STRING
      Attributes ::= SET OF Attribute
    }
    */

    try{
      Vector values = new Vector();

      ASN1[] contents = null;
      ASN1 asn1 = new ASN1(plain);
      contents = asn1.getContents();

      ASN1 privateKeyAlgorithm = contents[1];
      ASN1 privateKey = contents[2];

      contents = privateKeyAlgorithm.getContents();
      byte[] privateKeyAlgorithmID = contents[0].getContent();
      contents = contents[1].getContents();
      if(contents.length>0){
        for(int i = 0; i < contents.length; i++){
          values.addElement(contents[i].getContent());
        }
      }

      byte[] _data = privateKey.getContent();

      KeyPair _kpair = null;
      if(Util.array_equals(privateKeyAlgorithmID, rsaEncryption)){
        _kpair = new KeyPairRSA(jsch);
        _kpair.copy(this);
        if(_kpair.parse(_data)){
          kpair = _kpair;
        } 
      }
      else if(Util.array_equals(privateKeyAlgorithmID, dsaEncryption)){
        asn1 = new ASN1(_data);
        if(values.size() == 0) {  // embedded DSA parameters format
          /*
             SEQUENCE
               SEQUENCE
                 INTEGER    // P_array
                 INTEGER    // Q_array
                 INTEGER    // G_array
               INTEGER      // prv_array
          */
          contents = asn1.getContents();
          byte[] bar = contents[1].getContent();
          contents = contents[0].getContents();
          for(int i = 0; i < contents.length; i++){
            values.addElement(contents[i].getContent());
          }
          values.addElement(bar);
        }
        else {
          /*
             INTEGER      // prv_array
          */
          values.addElement(asn1.getContent());
        }

        byte[] P_array = (byte[])values.elementAt(0);
        byte[] Q_array = (byte[])values.elementAt(1);
        byte[] G_array = (byte[])values.elementAt(2);
        byte[] prv_array = (byte[])values.elementAt(3);
        // Y = g^X mode p
        byte[] pub_array =
          (new BigInteger(G_array)).
            modPow(new BigInteger(prv_array), new BigInteger(P_array)).
            toByteArray();

        KeyPairDSA _key = new KeyPairDSA(jsch,
                                         P_array, Q_array, G_array,
                                         pub_array, prv_array);
        plain = _key.getPrivateKey();

        _kpair = new KeyPairDSA(jsch);
        _kpair.copy(this);
        if(_kpair.parse(plain)){
          kpair = _kpair;
        }
      }
    }
    catch(ASN1Exception e){
      return false;
    }
    catch(Exception e){
      //System.err.println(e);
      return false;
    }
    return kpair != null;
  }

  public byte[] getPublicKeyBlob(){
    return kpair.getPublicKeyBlob();
  }

  byte[] getKeyTypeName(){ return kpair.getKeyTypeName();}
  public int getKeyType(){return kpair.getKeyType();}

  public int getKeySize(){
    return kpair.getKeySize();
  }

  public byte[] getSignature(byte[] data){
    return kpair.getSignature(data);
  }

  public Signature getVerifier(){
    return kpair.getVerifier();
  }

  public byte[] forSSHAgent() throws JSchException {
    return kpair.forSSHAgent();
  }

  public boolean decrypt(byte[] _passphrase){
    if(!isEncrypted()){
      return true;
    }
    if(_passphrase==null){
      return !isEncrypted();
    }

    /*
      SEQUENCE
        SEQUENCE
          OBJECT            :PBES2
          SEQUENCE
            SEQUENCE
              OBJECT            :PBKDF2
              SEQUENCE
                OCTET STRING      [HEX DUMP]:E4E24ADC9C00BD4D
                INTEGER           :0800
            SEQUENCE
              OBJECT            :aes-128-cbc
              OCTET STRING      [HEX DUMP]:5B66E6B3BF03944C92317BC370CC3AD0
        OCTET STRING      [HEX DUMP]:

or

      SEQUENCE
        SEQUENCE
          OBJECT            :pbeWithMD5AndDES-CBC
          SEQUENCE
            OCTET STRING      [HEX DUMP]:DBF75ECB69E3C0FC
            INTEGER           :0800
        OCTET STRING      [HEX DUMP]
    */

    try{

      ASN1[] contents = null;
      ASN1 asn1 = new ASN1(data);

      contents =  asn1.getContents();

      byte[] _data = contents[1].getContent();

      ASN1 pbes = contents[0];
      contents = pbes.getContents();
      byte[] pbesid = contents[0].getContent();
      ASN1 pbesparam = contents[1];

      byte[] salt = null;
      int iterations = 0;
      byte[] iv = null;
      byte[] encryptfuncid = null;

      if(Util.array_equals(pbesid, pbes2)){
        contents = pbesparam.getContents();
        ASN1 pbkdf = contents[0];
        ASN1 encryptfunc = contents[1];
        contents = pbkdf.getContents();
        byte[] pbkdfid = contents[0].getContent();
        ASN1 pbkdffunc = contents[1];
        contents = pbkdffunc.getContents();
        salt = contents[0].getContent();
        iterations = 
          Integer.parseInt((new BigInteger(contents[1].getContent())).toString());

        contents = encryptfunc.getContents();
        encryptfuncid = contents[0].getContent();
        iv = contents[1].getContent();
      }
      else if(Util.array_equals(pbesid, pbeWithMD5AndDESCBC)){
        // not supported
        return false;
      }
      else {
        return false;
      }

      Cipher cipher=getCipher(encryptfuncid);
      if(cipher==null) return false;

      byte[] key=null;
      try{
        Class c=Class.forName((String)JSch.getConfig("pbkdf"));
        PBKDF tmp=(PBKDF)(c.newInstance());
        key = tmp.getKey(_passphrase, salt, iterations, cipher.getBlockSize());
      }
      catch(Exception ee){
      }

      if(key==null){
        return false;
      }

      cipher.init(Cipher.DECRYPT_MODE, key, iv);
      Util.bzero(key);
      byte[] plain=new byte[_data.length];
      cipher.update(_data, 0, _data.length, plain, 0);
      if(parse(plain)){
        encrypted=false;
        return true;
      }
    }
    catch(ASN1Exception e){
      // System.err.println(e);
    }
    catch(Exception e){
      // System.err.println(e);
    }

    return false;
  }

  Cipher getCipher(byte[] id){
    Cipher cipher=null;
    String name = null;
    try{
      if(Util.array_equals(id, aes128cbc)){
        name="aes128-cbc";
      }
      else if(Util.array_equals(id, aes192cbc)){
        name="aes192-cbc";
      }
      else if(Util.array_equals(id, aes256cbc)){
        name="aes256-cbc";
      }
      Class c=Class.forName((String)JSch.getConfig(name));
      cipher=(Cipher)(c.newInstance());
    }
    catch(Exception e){
      if(JSch.getLogger().isEnabled(Logger.FATAL)){
        String message="";
        if(name==null){
          message="unknown oid: "+Util.toHex(id);
        }
        else {
          message="function "+name+" is not supported";
        }
        JSch.getLogger().log(Logger.FATAL, "PKCS8: "+message);
      }
    }
    return cipher;
  }
}
