GenOTP.cs

using System;
using System.Diagnostics;
using System.Globalization;
using System.IO;
using System.Security.Cryptography;
using System.Text;
using System.Windows.Forms;
using MissionPlanner.Comms;
using px4uploader;

namespace MissionPlanner
{
    public partial class GenOTP : Form
    {
        public GenOTP()
        {
            InitializeComponent();
        }

        private void BUT_makeotp_Click(object sender, EventArgs e)
        {
            if (txtboardsn.Text.Length != 24)
            {
                CustomMessageBox.Show("SN invalid length (should be 24 chars)");
                return;
            }

            if (!File.Exists(fileBrowsePrivateKey.filename))
            {
                CustomMessageBox.Show("Private key files doesnt exist");
                return;
            }

            //            byte[] testhex = { 0x00, 0x3D, 0x00, 0x1F, 0x32, 0x31, 0x47, 0x0C, 0x34, 0x30, 0x37, 0x36 };
            byte[] sn = new byte[txtboardsn.Text.Length/2];

            for (int index = 0; index < sn.Length; index++)
            {
                string byteValue = txtboardsn.Text.Substring(index*2, 2);
                sn[index] = byte.Parse(byteValue, NumberStyles.HexNumber, CultureInfo.InvariantCulture);
            }

            // 20 bytes - sha1
            Array.Resize(ref sn, 20);

            // read private key
            string privatekey = File.ReadAllText(fileBrowsePrivateKey.filename);

            RSACryptoServiceProvider rsa = DecodeRsaPrivateKey(Convert.FromBase64String(privatekey));

            byte[] signedhash = rsa.SignHash(sn, CryptoConfig.MapNameToOID("SHA1"));

            Console.WriteLine("SignHash {0}", Convert.ToBase64String(signedhash));

            using (BinaryWriter bw = new BinaryWriter(File.OpenWrite(fileBrowseOtpbin.filename)))
            {
                //    bw.Write('P');
                //    bw.Write('X');
                //    bw.Write('4');
                //    bw.Write('\0');

                //    bw.Write(byte.Parse(txt_id.Text, System.Globalization.NumberStyles.HexNumber));

                //   bw.Write(int.Parse(txt_vid.Text, System.Globalization.NumberStyles.HexNumber));
                //   bw.Write(int.Parse(txt_pid.Text, System.Globalization.NumberStyles.HexNumber));

                //    for (int a = 0; a < 32; a++)
                //   {
                //       bw.Write((byte)0xff);
                //   }

                //   bw.Seek(32, SeekOrigin.Begin);
                bw.Write(signedhash);
            }

            CustomMessageBox.Show("Done");
        }

        /// <summary>
        /// This helper function parses an RSA private key using the ASN.1 format
        /// </summary>
        /// <param name="privateKeyBytes">Byte array containing PEM string of private key.</param>
        /// <returns>An instance of <see cref="RSACryptoServiceProvider"/> rapresenting the requested private key.
        /// Null if method fails on retriving the key.</returns>
        public RSACryptoServiceProvider DecodeRsaPrivateKey(byte[] privateKeyBytes)
        {
            MemoryStream ms = new MemoryStream(privateKeyBytes);
            BinaryReader rd = new BinaryReader(ms);

            try
            {
                byte byteValue;
                ushort shortValue;

                shortValue = rd.ReadUInt16();

                switch (shortValue)
                {
                    case 0x8130:
                        // If true, data is little endian since the proper logical seq is 0x30 0x81
                        rd.ReadByte(); //advance 1 byte
                        break;
                    case 0x8230:
                        rd.ReadInt16(); //advance 2 bytes
                        break;
                    default:
                        Debug.Assert(false); // Improper ASN.1 format
                        return null;
                }

                shortValue = rd.ReadUInt16();
                if (shortValue != 0x0102) // (version number)
                {
                    Debug.Assert(false); // Improper ASN.1 format, unexpected version number
                    return null;
                }

                byteValue = rd.ReadByte();
                if (byteValue != 0x00)
                {
                    Debug.Assert(false); // Improper ASN.1 format
                    return null;
                }

                // The data following the version will be the ASN.1 data itself, which in our case
                // are a sequence of integers.

                // In order to solve a problem with instancing RSACryptoServiceProvider
                // via default constructor on .net 4.0 this is a hack
                CspParameters parms = new CspParameters();
                parms.Flags = CspProviderFlags.NoFlags;
                parms.KeyContainerName = Guid.NewGuid().ToString().ToUpperInvariant();
                parms.ProviderType = ((Environment.OSVersion.Version.Major > 5) ||
                                      ((Environment.OSVersion.Version.Major == 5) &&
                                       (Environment.OSVersion.Version.Minor >= 1)))
                    ? 0x18
                    : 1;

                RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(parms);
                RSAParameters rsAparams = new RSAParameters();

                rsAparams.Modulus = rd.ReadBytes(Helpers.DecodeIntegerSize(rd));

                // Argh, this is a pain.  From emperical testing it appears to be that RSAParameters doesn't like byte buffers that
                // have their leading zeros removed.  The RFC doesn't address this area that I can see, so it's hard to say that this
                // is a bug, but it sure would be helpful if it allowed that. So, there's some extra code here that knows what the
                // sizes of the various components are supposed to be.  Using these sizes we can ensure the buffer sizes are exactly
                // what the RSAParameters expect.  Thanks, Microsoft.
                RSAParameterTraits traits = new RSAParameterTraits(rsAparams.Modulus.Length*8);

                rsAparams.Modulus = Helpers.AlignBytes(rsAparams.Modulus, traits.size_Mod);
                rsAparams.Exponent = Helpers.AlignBytes(rd.ReadBytes(Helpers.DecodeIntegerSize(rd)), traits.size_Exp);
                rsAparams.D = Helpers.AlignBytes(rd.ReadBytes(Helpers.DecodeIntegerSize(rd)), traits.size_D);
                rsAparams.P = Helpers.AlignBytes(rd.ReadBytes(Helpers.DecodeIntegerSize(rd)), traits.size_P);
                rsAparams.Q = Helpers.AlignBytes(rd.ReadBytes(Helpers.DecodeIntegerSize(rd)), traits.size_Q);
                rsAparams.DP = Helpers.AlignBytes(rd.ReadBytes(Helpers.DecodeIntegerSize(rd)), traits.size_DP);
                rsAparams.DQ = Helpers.AlignBytes(rd.ReadBytes(Helpers.DecodeIntegerSize(rd)), traits.size_DQ);
                rsAparams.InverseQ = Helpers.AlignBytes(rd.ReadBytes(Helpers.DecodeIntegerSize(rd)), traits.size_InvQ);

                rsa.ImportParameters(rsAparams);
                return rsa;
            }
            catch (Exception)
            {
                Debug.Assert(false);
                return null;
            }
            finally
            {
                rd.Close();
            }
        }

        public class Helpers
        {
            public enum PemStringType
            {
                Certificate,
                RsaPrivateKey
            }

            /// <summary>
            /// This helper function parses an integer size from the reader using the ASN.1 format
            /// </summary>
            /// <param name="rd"></param>
            /// <returns></returns>
            public static int DecodeIntegerSize(System.IO.BinaryReader rd)
            {
                byte byteValue;
                int count;

                byteValue = rd.ReadByte();
                if (byteValue != 0x02) // indicates an ASN.1 integer value follows
                    return 0;

                byteValue = rd.ReadByte();
                if (byteValue == 0x81)
                {
                    count = rd.ReadByte(); // data size is the following byte
                }
                else if (byteValue == 0x82)
                {
                    byte hi = rd.ReadByte(); // data size in next 2 bytes
                    byte lo = rd.ReadByte();
                    count = BitConverter.ToUInt16(new[] {lo, hi}, 0);
                }
                else
                {
                    count = byteValue; // we already have the data size
                }

                //remove high order zeros in data
                while (rd.ReadByte() == 0x00)
                {
                    count -= 1;
                }
                rd.BaseStream.Seek(-1, System.IO.SeekOrigin.Current);

                return count;
            }

            /// <summary>
            /// 
            /// </summary>
            /// <param name="pemString"></param>
            /// <param name="type"></param>
            /// <returns></returns>
            public static byte[] GetBytesFromPEM(string pemString, PemStringType type)
            {
                string header;
                string footer;

                switch (type)
                {
                    case PemStringType.Certificate:
                        header = "-----BEGIN CERTIFICATE-----";
                        footer = "-----END CERTIFICATE-----";
                        break;
                    case PemStringType.RsaPrivateKey:
                        header = "-----BEGIN RSA PRIVATE KEY-----";
                        footer = "-----END RSA PRIVATE KEY-----";
                        break;
                    default:
                        return null;
                }

                int start = pemString.IndexOf(header) + header.Length;
                int end = pemString.IndexOf(footer, start) - start;
                return Convert.FromBase64String(pemString.Substring(start, end));
            }

            /// <summary>
            /// 
            /// </summary>
            /// <param name="inputBytes"></param>
            /// <param name="alignSize"></param>
            /// <returns></returns>
            public static byte[] AlignBytes(byte[] inputBytes, int alignSize)
            {
                int inputBytesSize = inputBytes.Length;

                if ((alignSize != -1) && (inputBytesSize < alignSize))
                {
                    byte[] buf = new byte[alignSize];
                    for (int i = 0; i < inputBytesSize; ++i)
                    {
                        buf[i + (alignSize - inputBytesSize)] = inputBytes[i];
                    }
                    return buf;
                }
                else
                {
                    return inputBytes; // Already aligned, or doesn't need alignment
                }
            }
        }

        internal class RSAParameterTraits
        {
            public RSAParameterTraits(int modulusLengthInBits)
            {
                // The modulus length is supposed to be one of the common lengths, which is the commonly referred to strength of the key,
                // like 1024 bit, 2048 bit, etc.  It might be a few bits off though, since if the modulus has leading zeros it could show
                // up as 1016 bits or something like that.
                int assumedLength = -1;
                double logbase = Math.Log(modulusLengthInBits, 2);
                if (logbase == (int) logbase)
                {
                    // It's already an even power of 2
                    assumedLength = modulusLengthInBits;
                }
                else
                {
                    // It's not an even power of 2, so round it up to the nearest power of 2.
                    assumedLength = (int) (logbase + 1.0);
                    assumedLength = (int) (Math.Pow(2, assumedLength));
                    System.Diagnostics.Debug.Assert(false);
                        // Can this really happen in the field?  I've never seen it, so if it happens
                    // you should verify that this really does the 'right' thing!
                }

                switch (assumedLength)
                {
                    case 1024:
                        this.size_Mod = 0x80;
                        this.size_Exp = -1;
                        this.size_D = 0x80;
                        this.size_P = 0x40;
                        this.size_Q = 0x40;
                        this.size_DP = 0x40;
                        this.size_DQ = 0x40;
                        this.size_InvQ = 0x40;
                        break;
                    case 2048:
                        this.size_Mod = 0x100;
                        this.size_Exp = -1;
                        this.size_D = 0x100;
                        this.size_P = 0x80;
                        this.size_Q = 0x80;
                        this.size_DP = 0x80;
                        this.size_DQ = 0x80;
                        this.size_InvQ = 0x80;
                        break;
                    case 4096:
                        this.size_Mod = 0x200;
                        this.size_Exp = -1;
                        this.size_D = 0x200;
                        this.size_P = 0x100;
                        this.size_Q = 0x100;
                        this.size_DP = 0x100;
                        this.size_DQ = 0x100;
                        this.size_InvQ = 0x100;
                        break;
                    default:
                        System.Diagnostics.Debug.Assert(false); // Unknown key size?
                        break;
                }
            }

            public int size_Mod = -1;
            public int size_Exp = -1;
            public int size_D = -1;
            public int size_P = -1;
            public int size_Q = -1;
            public int size_DP = -1;
            public int size_DQ = -1;
            public int size_InvQ = -1;
        }

        private void BUT_sn_Click(object sender, EventArgs e)
        {
            px4uploader.Uploader up;

            CustomMessageBox.Show("Please unplug press ok, and plug board in", "px4");

            DateTime DEADLINE = DateTime.Now.AddSeconds(30);
            while (DateTime.Now < DEADLINE)
            {
                string[] allports = SerialPort.GetPortNames();

                foreach (string port in allports)
                {
                    Console.WriteLine(DateTime.Now.Millisecond + " Trying Port " + port);

                    try
                    {
                        up = new Uploader(port, 115200);
                    }
                    catch (Exception ex)
                    {
                        //System.Threading.Thread.Sleep(50);
                        Console.WriteLine(ex.Message);
                        continue;
                    }

                    try
                    {
                        up.identify();
                        Console.WriteLine("Found board type {0} boardrev {1} bl rev {2} fwmax {3} on {4}", up.board_type,
                            up.board_rev, up.bl_rev, up.fw_maxsize, port);

                        byte[] sn = up.__get_sn();

                        StringBuilder sb = new StringBuilder();

                        Console.Write("SN: ");
                        for (int s = 0; s < sn.Length; s += 1)
                        {
                            Console.Write(sn[s].ToString("X2"));
                            sb.Append(sn[s].ToString("X2"));
                        }

                        txtboardsn.Text = sb.ToString();

                        up.close();

                        CustomMessageBox.Show("Done");
                        return;
                    }
                    catch (Exception)
                    {
                        Console.WriteLine("Not There..");
                        //Console.WriteLine(ex.Message);
                        up.close();
                        continue;
                    }
                }
            }
        }
    }
}