private static IKeyPair ExtractKeyPair(PrivateKeyFileDataReader privateKeySectionReader)
{
var keyType = privateKeySectionReader.ReadString(Encoding.UTF8);
IKeyPair keyPair = null;
if (keyType == KeyTypes.ED25519)
{
var publicKey = privateKeySectionReader.ReadBytes(privateKeySectionReader.ReadInt32());
privateKeySectionReader.ReadInt32(); //length of private + public key
var privateKey = privateKeySectionReader.ReadBytes(32);
privateKeySectionReader.ReadBytes(32); //public key (again)
var comment = privateKeySectionReader.ReadString(Encoding.UTF8);
keyPair = new Ed25519KeyPair(comment, publicKey, privateKey);
}
else if (keyType == KeyTypes.RSA)
{
var n = privateKeySectionReader.ReadBigInteger(); //Modulus
var e = privateKeySectionReader.ReadBigInteger(); //Public Exponent
var d = privateKeySectionReader.ReadBigInteger(); //Private Exponent
var iqmp = privateKeySectionReader.ReadBigInteger(); //q^-1 mod p
var p = privateKeySectionReader.ReadBigInteger(); //Prime 1
var q = privateKeySectionReader.ReadBigInteger(); //Prime 2
var comment = privateKeySectionReader.ReadString(Encoding.UTF8);
keyPair = new RsaKeyPair(comment, n, e, d, iqmp, p, q);
}
else if (keyType == KeyTypes.ECDSA256 || keyType == KeyTypes.ECDSA384 || keyType == KeyTypes.ECDSA521)
{
int curveLength = privateKeySectionReader.ReadInt32();
var curve = Encoding.ASCII.GetString(privateKeySectionReader.ReadBytes(curveLength));
var publicKey = privateKeySectionReader.ReadBytes(privateKeySectionReader.ReadInt32());
var privateKey = privateKeySectionReader.ReadBytes(privateKeySectionReader.ReadInt32());
var comment = privateKeySectionReader.ReadString(Encoding.UTF8);
keyPair = new EcdsaKeyPair(keyType, comment, curve, publicKey, privateKey);
}
else if (keyType == KeyTypes.DSA)
{
var p = privateKeySectionReader.ReadBigInteger();
var q = privateKeySectionReader.ReadBigInteger();
var g = privateKeySectionReader.ReadBigInteger();
var y = privateKeySectionReader.ReadBigInteger();
var x = privateKeySectionReader.ReadBigInteger();
var comment = privateKeySectionReader.ReadString(Encoding.UTF8);
keyPair = new DsaKeyPair(comment, p, q, g, y, x);
}
else
{
throw new OpenSshKeyParseException($"key type '{keyType}' is not supported by this parser");
}
return(keyPair);
}
public static IKeyPair ParseOpenSshKeyFile(string privateKeyFileText, string passPhrase = null)
{
ValidPrivateKeyFileText(privateKeyFileText);
try
{
IKeyPair keyPair = null;
ValidateHeader(privateKeyFileText);
using (var keyFileReader = GetPrivateKeyFileDataReader(privateKeyFileText))
{
ValidateMagicHeader(keyFileReader.ReadBytes(AUTH_MAGIC.Length));
var cipherName = keyFileReader.ReadString(Encoding.UTF8);
var kdfName = keyFileReader.ReadString(Encoding.UTF8);
byte[] salt = null;
var rounds = 0;
if (keyFileReader.ReadInt32() > 0) //kdf options
{
salt = keyFileReader.ReadBytes(keyFileReader.ReadInt32());
rounds = keyFileReader.ReadInt32();
}
ValidateEncryptionFields(cipherName, kdfName, passPhrase);
ValidateNumberOfKeys(keyFileReader.ReadInt32());
keyFileReader.ReadBytes(keyFileReader.ReadInt32()); //skip public key section
//we skipped the public key section but for reference, here is what parsing it would look like:
/*
* using (var publicKeySectionReader = new PrivateKeyFileDataReader(keyFileReader.ReadBytes(keyFileReader.ReadInt32())))
* {
* publicKeySectionReader.ReadString(Encoding.UTF8); //key type
* publicKeySectionReader.ReadBytes(); //public key, the parts of which will be dependant on the key type
* }
*/
var privateKeySectionBytes = keyFileReader.ReadBytes(keyFileReader.ReadInt32());
if (cipherName != "none")
{
privateKeySectionBytes = DecryptPrivateKeySection(cipherName, privateKeySectionBytes, salt, rounds, passPhrase);
}
ValidatePrivateKeySectionLength(privateKeySectionBytes.Length);
using (var privateKeySectionReader = new PrivateKeyFileDataReader(privateKeySectionBytes))
{
ValidateCheckInts(privateKeySectionReader.ReadInt32(), privateKeySectionReader.ReadInt32());
keyPair = ExtractKeyPair(privateKeySectionReader);
ValidatePrivateKeyPadding(privateKeySectionReader.ReadBytes());
}
}
return(keyPair);
}
catch (Exception e)
{
if (e is OpenSshKeyParseException)
{
throw e;
}
throw new OpenSshKeyParseException($"unexpected failure parsing key: {e.Message}");
}
}