Files
DearFTP/DearFTP/Utils/OpenSslKey.cs
2019-07-20 13:06:17 +02:00

531 lines
19 KiB
C#

//**********************************************************************************
//
//OpenSSLKey
// .NET 2.0 OpenSSL Public & Private Key Parser
//
// Copyright (C) 2008 JavaScience Consulting
//
//***********************************************************************************
//
// opensslkey.cs
//
// Reads and parses:
// (1) OpenSSL PEM or DER public keys
// (2) OpenSSL PEM or DER traditional SSLeay private keys (encrypted and unencrypted)
// (3) PKCS #8 PEM or DER encoded private keys (encrypted and unencrypted)
// Keys in PEM format must have headers/footers .
// Encrypted Private Key in SSLEay format not supported in DER
// Removes header/footer lines.
// For traditional SSLEAY PEM private keys, checks for encrypted format and
// uses PBE to extract 3DES key.
// For SSLEAY format, only supports encryption format: DES-EDE3-CBC
// For PKCS #8, only supports PKCS#5 v2.0 3des.
// Parses private and public key components and returns .NET RSA object.
// Creates dummy unsigned certificate linked to private keypair and
// optionally exports to pkcs #12
//
// See also:
// http://www.openssl.org/docs/crypto/pem.html#PEM_ENCRYPTION_FORMAT
//**************************************************************************************
using System;
using System.IO;
using System.Runtime.InteropServices;
using System.Security;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Text;
namespace DearFTP.Utils
{
[StructLayout(LayoutKind.Sequential)]
public struct CRYPT_KEY_PROV_INFO
{
[MarshalAs(UnmanagedType.LPWStr)] public string pwszContainerName;
[MarshalAs(UnmanagedType.LPWStr)] public string pwszProvName;
public uint dwProvType;
public uint dwFlags;
public uint cProvParam;
public IntPtr rgProvParam;
public uint dwKeySpec;
}
[StructLayout(LayoutKind.Sequential)]
public struct CERT_NAME_BLOB
{
public int cbData;
public IntPtr pbData;
}
public class OpenSslKey
{
//-------- Get the binary PKCS #8 PRIVATE key --------
public static byte[] DecodePkcs8PrivateKey(string instr)
{
const string pemp8header = "-----BEGIN PRIVATE KEY-----";
const string pemp8footer = "-----END PRIVATE KEY-----";
string pemstr = instr.Trim();
byte[] binkey;
if (!pemstr.StartsWith(pemp8header) || !pemstr.EndsWith(pemp8footer))
return null;
StringBuilder sb = new StringBuilder(pemstr);
sb.Replace(pemp8header, ""); //remove headers/footers, if present
sb.Replace(pemp8footer, "");
string pubstr = sb.ToString().Trim(); //get string after removing leading/trailing whitespace
try
{
binkey = Convert.FromBase64String(pubstr);
}
catch (FormatException)
{ //if can't b64 decode, data is not valid
return null;
}
return binkey;
}
//------- Parses binary asn.1 PKCS #8 PrivateKeyInfo; returns RSACryptoServiceProvider ---
public static RSACryptoServiceProvider DecodePrivateKeyInfo(byte[] pkcs8)
{
// encoded OID sequence for PKCS #1 rsaEncryption szOID_RSA_RSA = "1.2.840.113549.1.1.1"
// this byte[] includes the sequence byte and terminal encoded null
byte[] SeqOID = { 0x30, 0x0D, 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01, 0x05, 0x00 };
byte[] seq;
// --------- Set up stream to read the asn.1 encoded SubjectPublicKeyInfo blob ------
MemoryStream mem = new MemoryStream(pkcs8);
int lenstream = (int)mem.Length;
BinaryReader binr = new BinaryReader(mem); //wrap Memory Stream with BinaryReader for easy reading
byte bt;
ushort twobytes;
try
{
twobytes = binr.ReadUInt16();
if (twobytes == 0x8130) //data read as little endian order (actual data order for Sequence is 30 81)
binr.ReadByte(); //advance 1 byte
else if (twobytes == 0x8230)
binr.ReadInt16(); //advance 2 bytes
else
return null;
bt = binr.ReadByte();
if (bt != 0x02)
return null;
twobytes = binr.ReadUInt16();
if (twobytes != 0x0001)
return null;
seq = binr.ReadBytes(15); //read the Sequence OID
if (!CompareBytearrays(seq, SeqOID)) //make sure Sequence for OID is correct
return null;
bt = binr.ReadByte();
if (bt != 0x04) //expect an Octet string
return null;
bt = binr.ReadByte(); //read next byte, or next 2 bytes is 0x81 or 0x82; otherwise bt is the byte count
if (bt == 0x81)
binr.ReadByte();
else
if (bt == 0x82)
binr.ReadUInt16();
//------ at this stage, the remaining sequence should be the RSA private key
byte[] rsaprivkey = binr.ReadBytes((int)(lenstream - mem.Position));
RSACryptoServiceProvider rsacsp = DecodeRSAPrivateKey(rsaprivkey);
return rsacsp;
}
catch (Exception)
{
return null;
}
finally
{
binr.Close();
}
}
//-------- Get the binary PKCS #8 Encrypted PRIVATE key --------
public static byte[] DecodePkcs8EncPrivateKey(string instr)
{
const string pemp8encheader = "-----BEGIN ENCRYPTED PRIVATE KEY-----";
const string pemp8encfooter = "-----END ENCRYPTED PRIVATE KEY-----";
string pemstr = instr.Trim();
byte[] binkey;
if (!pemstr.StartsWith(pemp8encheader) || !pemstr.EndsWith(pemp8encfooter))
return null;
StringBuilder sb = new StringBuilder(pemstr);
sb.Replace(pemp8encheader, ""); //remove headers/footers, if present
sb.Replace(pemp8encfooter, "");
string pubstr = sb.ToString().Trim(); //get string after removing leading/trailing whitespace
try
{
binkey = Convert.FromBase64String(pubstr);
}
catch (System.FormatException)
{ //if can't b64 decode, data is not valid
return null;
}
return binkey;
}
//------- Parses binary asn.1 EncryptedPrivateKeyInfo; returns RSACryptoServiceProvider ---
public static RSACryptoServiceProvider DecodeEncryptedPrivateKeyInfo(byte[] encpkcs8)
{
// encoded OID sequence for PKCS #1 rsaEncryption szOID_RSA_RSA = "1.2.840.113549.1.1.1"
// this byte[] includes the sequence byte and terminal encoded null
byte[] OIDpkcs5PBES2 = { 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x05, 0x0D };
byte[] OIDpkcs5PBKDF2 = { 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x05, 0x0C };
byte[] OIDdesEDE3CBC = { 0x06, 0x08, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x03, 0x07 };
byte[] seqdes;
byte[] seq;
byte[] salt;
byte[] IV;
byte[] encryptedpkcs8;
byte[] pkcs8;
int saltsize, ivsize, encblobsize;
int iterations;
// --------- Set up stream to read the asn.1 encoded SubjectPublicKeyInfo blob ------
MemoryStream mem = new MemoryStream(encpkcs8);
BinaryReader binr = new BinaryReader(mem); //wrap Memory Stream with BinaryReader for easy reading
byte bt;
ushort twobytes;
try
{
twobytes = binr.ReadUInt16();
if (twobytes == 0x8130) //data read as little endian order (actual data order for Sequence is 30 81)
binr.ReadByte(); //advance 1 byte
else if (twobytes == 0x8230)
binr.ReadInt16(); //advance 2 bytes
else
return null;
twobytes = binr.ReadUInt16(); //inner sequence
if (twobytes == 0x8130)
binr.ReadByte();
else if (twobytes == 0x8230)
binr.ReadInt16();
seq = binr.ReadBytes(11); //read the Sequence OID
if (!CompareBytearrays(seq, OIDpkcs5PBES2)) //is it a OIDpkcs5PBES2 ?
return null;
twobytes = binr.ReadUInt16(); //inner sequence for pswd salt
if (twobytes == 0x8130)
binr.ReadByte();
else if (twobytes == 0x8230)
binr.ReadInt16();
twobytes = binr.ReadUInt16(); //inner sequence for pswd salt
if (twobytes == 0x8130)
binr.ReadByte();
else if (twobytes == 0x8230)
binr.ReadInt16();
seq = binr.ReadBytes(11); //read the Sequence OID
if (!CompareBytearrays(seq, OIDpkcs5PBKDF2)) //is it a OIDpkcs5PBKDF2 ?
return null;
twobytes = binr.ReadUInt16();
if (twobytes == 0x8130)
binr.ReadByte();
else if (twobytes == 0x8230)
binr.ReadInt16();
bt = binr.ReadByte();
if (bt != 0x04) //expect octet string for salt
return null;
saltsize = binr.ReadByte();
salt = binr.ReadBytes(saltsize);
bt = binr.ReadByte();
if (bt != 0x02) //expect an integer for PBKF2 interation count
return null;
int itbytes = binr.ReadByte(); //PBKD2 iterations should fit in 2 bytes.
if (itbytes == 1)
iterations = binr.ReadByte();
else if (itbytes == 2)
iterations = 256 * binr.ReadByte() + binr.ReadByte();
else
return null;
twobytes = binr.ReadUInt16();
if (twobytes == 0x8130)
binr.ReadByte();
else if (twobytes == 0x8230)
binr.ReadInt16();
seqdes = binr.ReadBytes(10); //read the Sequence OID
if (!CompareBytearrays(seqdes, OIDdesEDE3CBC)) //is it a OIDdes-EDE3-CBC ?
return null;
bt = binr.ReadByte();
if (bt != 0x04) //expect octet string for IV
return null;
ivsize = binr.ReadByte(); // IV byte size should fit in one byte (24 expected for 3DES)
IV = binr.ReadBytes(ivsize);
bt = binr.ReadByte();
if (bt != 0x04) // expect octet string for encrypted PKCS8 data
return null;
bt = binr.ReadByte();
if (bt == 0x81)
encblobsize = binr.ReadByte(); // data size in next byte
else if (bt == 0x82)
encblobsize = 256 * binr.ReadByte() + binr.ReadByte();
else
encblobsize = bt; // we already have the data size
encryptedpkcs8 = binr.ReadBytes(encblobsize);
SecureString secpswd = GetSecPswd("Enter password for Encrypted PKCS #8 ==>");
pkcs8 = DecryptPBDK2(encryptedpkcs8, salt, IV, secpswd, iterations);
if (pkcs8 == null) // probably a bad pswd entered.
return null;
//----- With a decrypted pkcs #8 PrivateKeyInfo blob, decode it to an RSA ---
RSACryptoServiceProvider rsa = DecodePrivateKeyInfo(pkcs8);
return rsa;
}
catch (Exception)
{
return null;
}
finally
{
binr.Close();
}
}
// ------ Uses PBKD2 to derive a 3DES key and decrypts data --------
public static byte[] DecryptPBDK2(byte[] edata, byte[] salt, byte[] IV, SecureString secpswd, int iterations)
{
byte[] psbytes = new byte[secpswd.Length];
IntPtr unmanagedPswd = Marshal.SecureStringToGlobalAllocAnsi(secpswd);
Marshal.Copy(unmanagedPswd, psbytes, 0, psbytes.Length);
Marshal.ZeroFreeGlobalAllocAnsi(unmanagedPswd);
try
{
Rfc2898DeriveBytes kd = new Rfc2898DeriveBytes(psbytes, salt, iterations);
TripleDES decAlg = TripleDES.Create();
decAlg.Key = kd.GetBytes(24);
decAlg.IV = IV;
MemoryStream memstr = new MemoryStream();
CryptoStream decrypt = new CryptoStream(memstr, decAlg.CreateDecryptor(), CryptoStreamMode.Write);
decrypt.Write(edata, 0, edata.Length);
decrypt.Flush();
decrypt.Close(); // this is REQUIRED.
byte[] cleartext = memstr.ToArray();
return cleartext;
}
catch (Exception e)
{
Console.WriteLine("Problem decrypting: {0}", e.Message);
return null;
}
}
//------- Parses binary ans.1 RSA private key; returns RSACryptoServiceProvider ---
public static RSACryptoServiceProvider DecodeRSAPrivateKey(byte[] privkey)
{
byte[] MODULUS, E, D, P, Q, DP, DQ, IQ;
// --------- Set up stream to decode the asn.1 encoded RSA private key ------
MemoryStream mem = new MemoryStream(privkey);
BinaryReader binr = new BinaryReader(mem); //wrap Memory Stream with BinaryReader for easy reading
byte bt;
ushort twobytes;
int elems;
try
{
twobytes = binr.ReadUInt16();
if (twobytes == 0x8130) //data read as little endian order (actual data order for Sequence is 30 81)
binr.ReadByte(); //advance 1 byte
else if (twobytes == 0x8230)
binr.ReadInt16(); //advance 2 bytes
else
return null;
twobytes = binr.ReadUInt16();
if (twobytes != 0x0102) //version number
return null;
bt = binr.ReadByte();
if (bt != 0x00)
return null;
//------ all private key components are Integer sequences ----
elems = GetIntegerSize(binr);
MODULUS = binr.ReadBytes(elems);
elems = GetIntegerSize(binr);
E = binr.ReadBytes(elems);
elems = GetIntegerSize(binr);
D = binr.ReadBytes(elems);
elems = GetIntegerSize(binr);
P = binr.ReadBytes(elems);
elems = GetIntegerSize(binr);
Q = binr.ReadBytes(elems);
elems = GetIntegerSize(binr);
DP = binr.ReadBytes(elems);
elems = GetIntegerSize(binr);
DQ = binr.ReadBytes(elems);
elems = GetIntegerSize(binr);
IQ = binr.ReadBytes(elems);
// ------- create RSACryptoServiceProvider instance and initialize with public key -----
RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();
RSAParameters RSAparams = new RSAParameters
{
Modulus = MODULUS,
Exponent = E,
D = D,
P = P,
Q = Q,
DP = DP,
DQ = DQ,
InverseQ = IQ
};
RSA.ImportParameters(RSAparams);
return RSA;
}
catch (Exception)
{
return null;
}
finally { binr.Close(); }
}
private static int GetIntegerSize(BinaryReader binr)
{
byte bt = binr.ReadByte();
if (bt != 0x02) //expect integer
return 0;
bt = binr.ReadByte();
int count;
if (bt == 0x81)
count = binr.ReadByte(); // data size in next byte
else if (bt == 0x82)
{
byte highbyte = binr.ReadByte();
byte lowbyte = binr.ReadByte();
byte[] modint = { lowbyte, highbyte, 0x00, 0x00 };
count = BitConverter.ToInt32(modint, 0);
}
else
{
count = bt; // we already have the data size
}
while (binr.ReadByte() == 0x00)
{ //remove high order zeros in data
count -= 1;
}
binr.BaseStream.Seek(-1, SeekOrigin.Current); //last ReadByte wasn't a removed zero, so back up a byte
return count;
}
private static SecureString GetSecPswd(string prompt)
{
SecureString password = new SecureString();
Console.ForegroundColor = ConsoleColor.Gray;
Console.Write(prompt);
Console.ForegroundColor = ConsoleColor.Magenta;
while (true)
{
ConsoleKeyInfo cki = Console.ReadKey(true);
if (cki.Key == ConsoleKey.Enter)
{
Console.ForegroundColor = ConsoleColor.Gray;
Console.WriteLine();
return password;
}
else if (cki.Key == ConsoleKey.Backspace)
{
// remove the last asterisk from the screen...
if (password.Length > 0)
{
Console.SetCursorPosition(Console.CursorLeft - 1, Console.CursorTop);
Console.Write(" ");
Console.SetCursorPosition(Console.CursorLeft - 1, Console.CursorTop);
password.RemoveAt(password.Length - 1);
}
}
else if (cki.Key == ConsoleKey.Escape)
{
Console.ForegroundColor = ConsoleColor.Gray;
Console.WriteLine();
return password;
}
else if (char.IsLetterOrDigit(cki.KeyChar) || char.IsSymbol(cki.KeyChar))
{
if (password.Length < 20)
{
password.AppendChar(cki.KeyChar);
Console.Write("*");
}
else
{
Console.Beep();
}
}
else
{
Console.Beep();
}
}
}
private static bool CompareBytearrays(byte[] a, byte[] b)
{
if (a.Length != b.Length)
return false;
int i = 0;
foreach (byte c in a)
{
if (c != b[i])
return false;
i++;
}
return true;
}
}
}