/// <summary>
/// Read private key parameters.
/// </summary>
/// <param name="passphrase">passphrase for decrypt the key file</param>
/// <param name="keyPair">key pair</param>
/// <param name="comment">comment or empty if it didn't exist</param>
public void Load(string passphrase, out KeyPair keyPair, out string comment)
{
PEMKeyType keyType;
String base64Text;
bool encrypted = false;
CipherAlgorithm?encryption = null;
byte[] iv = null;
int keySize = 0;
int ivSize = 0;
using (StreamReader sreader = GetStreamReader()) {
string line = sreader.ReadLine();
if (line == null)
{
throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (unexpected eof)");
}
if (line == PrivateKeyFileHeader.SSH2_OPENSSH_HEADER_RSA)
{
keyType = PEMKeyType.RSA;
}
else if (line == PrivateKeyFileHeader.SSH2_OPENSSH_HEADER_DSA)
{
keyType = PEMKeyType.DSA;
}
else if (line == PrivateKeyFileHeader.SSH2_OPENSSH_HEADER_ECDSA)
{
keyType = PEMKeyType.ECDSA;
}
else
{
throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (unexpected key type)");
}
string footer = line.Replace("BEGIN", "END");
StringBuilder buf = new StringBuilder();
comment = String.Empty;
while (true)
{
line = sreader.ReadLine();
if (line == null)
{
throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (unexpected eof)");
}
if (line == footer)
{
break;
}
if (line.IndexOf(':') >= 0)
{
if (line.StartsWith("Proc-Type:"))
{
string[] w = line.Substring("Proc-Type:".Length).Trim().Split(',');
if (w.Length < 1)
{
throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (invalid Proc-Type)");
}
if (w[0] != "4")
{
throw new SSHException(Strings.GetString("UnsupportedPrivateKeyFormat")
+ " (" + Strings.GetString("Reason_UnsupportedProcType") + ")");
}
if (w.Length >= 2 && w[1] == "ENCRYPTED")
{
encrypted = true;
}
}
else if (line.StartsWith("DEK-Info:"))
{
string[] w = line.Substring("DEK-Info:".Length).Trim().Split(',');
if (w.Length < 2)
{
throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (invalid DEK-Info)");
}
switch (w[0])
{
case "DES-EDE3-CBC":
encryption = CipherAlgorithm.TripleDES;
ivSize = 8;
keySize = 24;
break;
case "AES-128-CBC":
encryption = CipherAlgorithm.AES128;
ivSize = 16;
keySize = 16;
break;
default:
throw new SSHException(Strings.GetString("UnsupportedPrivateKeyFormat")
+ " (" + Strings.GetString("Reason_UnsupportedEncryptionType") + ")");
}
iv = HexToByteArray(w[1]);
if (iv == null || iv.Length != ivSize)
{
throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (invalid IV)");
}
}
}
else
{
buf.Append(line);
}
}
base64Text = buf.ToString();
}
byte[] keydata = Base64.Decode(Encoding.ASCII.GetBytes(base64Text));
if (encrypted)
{
if (!encryption.HasValue || iv == null)
{
throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (missing encryption type or IV)");
}
byte[] key = PassphraseToKey(passphrase, iv, keySize);
Cipher cipher = CipherFactory.CreateCipher(SSHProtocol.SSH2, encryption.Value, key, iv);
if (keydata.Length % cipher.BlockSize != 0)
{
throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (invalid key data size)");
}
cipher.Decrypt(keydata, 0, keydata.Length, keydata, 0);
}
using (MemoryStream keyDataStream = new MemoryStream(keydata, false)) {
BERReader reader = new BERReader(keyDataStream);
if (!reader.ReadSequence())
{
throw new SSHException(Strings.GetString("WrongPassphrase"));
}
if (keyType == PEMKeyType.RSA)
{
/* from OpenSSL rsa_asn1.c
*
* ASN1_SIMPLE(RSA, version, LONG),
* ASN1_SIMPLE(RSA, n, BIGNUM),
* ASN1_SIMPLE(RSA, e, BIGNUM),
* ASN1_SIMPLE(RSA, d, BIGNUM),
* ASN1_SIMPLE(RSA, p, BIGNUM),
* ASN1_SIMPLE(RSA, q, BIGNUM),
* ASN1_SIMPLE(RSA, dmp1, BIGNUM),
* ASN1_SIMPLE(RSA, dmq1, BIGNUM),
* ASN1_SIMPLE(RSA, iqmp, BIGNUM)
*/
BigInteger v, n, e, d, p, q, dmp1, dmq1, iqmp;
if (!reader.ReadInteger(out v) ||
!reader.ReadInteger(out n) ||
!reader.ReadInteger(out e) ||
!reader.ReadInteger(out d) ||
!reader.ReadInteger(out p) ||
!reader.ReadInteger(out q) ||
!reader.ReadInteger(out dmp1) ||
!reader.ReadInteger(out dmq1) ||
!reader.ReadInteger(out iqmp))
{
throw new SSHException(Strings.GetString("WrongPassphrase"));
}
BigInteger u = p.ModInverse(q); // inverse of p mod q
keyPair = new RSAKeyPair(e, d, n, u, p, q);
}
else if (keyType == PEMKeyType.DSA)
{
/* from OpenSSL dsa_asn1.c
*
* ASN1_SIMPLE(DSA, version, LONG),
* ASN1_SIMPLE(DSA, p, BIGNUM),
* ASN1_SIMPLE(DSA, q, BIGNUM),
* ASN1_SIMPLE(DSA, g, BIGNUM),
* ASN1_SIMPLE(DSA, pub_key, BIGNUM),
* ASN1_SIMPLE(DSA, priv_key, BIGNUM)
*/
BigInteger v, p, q, g, y, x;
if (!reader.ReadInteger(out v) ||
!reader.ReadInteger(out p) ||
!reader.ReadInteger(out q) ||
!reader.ReadInteger(out g) ||
!reader.ReadInteger(out y) ||
!reader.ReadInteger(out x))
{
throw new SSHException(Strings.GetString("WrongPassphrase"));
}
keyPair = new DSAKeyPair(p, g, q, y, x);
}
else if (keyType == PEMKeyType.ECDSA)
{
/* from OpenSSL ec_asn1.c
*
* ASN1_SIMPLE(EC_PRIVATEKEY, version, LONG),
* ASN1_SIMPLE(EC_PRIVATEKEY, privateKey, ASN1_OCTET_STRING),
* ASN1_EXP_OPT(EC_PRIVATEKEY, parameters, ECPKPARAMETERS, 0),
* ------
* ASN1_SIMPLE(ECPKPARAMETERS, value.named_curve, ASN1_OBJECT),
* ------
* ASN1_EXP_OPT(EC_PRIVATEKEY, publicKey, ASN1_BIT_STRING, 1)
*/
int len;
byte[] privateKey;
byte[] publicKey;
string namedCurve;
BigInteger v;
if (!reader.ReadInteger(out v) ||
!reader.ReadOctetString(out privateKey) ||
!reader.ReadTag(BERReader.TagClass.ContextSpecific, true, 0, out len) ||
!reader.ReadObjectIdentifier(out namedCurve) ||
!reader.ReadTag(BERReader.TagClass.ContextSpecific, true, 1, out len) ||
!reader.ReadBitString(out publicKey))
{
throw new SSHException(Strings.GetString("WrongPassphrase"));
}
EllipticCurve curve = EllipticCurve.FindByOID(namedCurve);
if (curve == null)
{
throw new SSHException(Strings.GetString("UnsupportedEllipticCurveInKeyPair"));
}
ECPoint ecPublicKeyPoint;
if (!ECPoint.Parse(publicKey, curve, out ecPublicKeyPoint))
{
throw new SSHException(Strings.GetString("KeysAreBroken"));
}
var ecKeyPair = new ECDSAKeyPair(curve, new ECDSAPublicKey(curve, ecPublicKeyPoint), new BigInteger(privateKey));
if (!ecKeyPair.CheckKeyConsistency())
{
throw new SSHException(Strings.GetString("KeysAreBroken"));
}
keyPair = ecKeyPair;
}
else
{
throw new SSHException("Unknown file type. This should not happen.");
}
}
}
