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@ayende

ayende/license-generation.cs

Created February 7, 2016 23:25
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  1. ayende revised this gist Feb 7, 2016. 1 changed file with 244 additions and 1 deletion.
    245 changes: 244 additions & 1 deletion license-generation.cs
    View file
    Original file line number Diff line number Diff line change
    @@ -1 +1,244 @@
    c:\users\ayende\documents\visual studio 2015\Projects\ConsoleApplication10\ConsoleApplication10\Program.cs
    using System;
    using System.Collections.Generic;
    using System.IO;
    using System.Linq;
    using System.Security.Cryptography;
    using Newtonsoft.Json;

    namespace ConsoleApp6
    {
    public class Program
    {
    const string license = @"{
    'expiration': '2017-01-17T00:00:00.0000000',
    'type': 1,
    'version': 3,
    'maxRamUtilization': 12,
    'maxParallelism': 6,
    'allowWindowsClustering': false,
    'OEM': false,
    'numberOfDatabases': 0,
    'fips': false,
    'periodicBackup': true,
    'quotas': false,
    'authorization': true,
    'documentExpiration': true,
    'replication': true,
    'versioning': true,
    'maxSizeInGb': 0,
    'ravenfs': true,
    'encryption': true,
    'compression': false,
    'updatesExpiration': '2017-01-17T00:00:00.0000000',
    }";

    public static void Main(string[] args)
    {
    using (var dsa = new DSACryptoServiceProvider())
    {
    var exportCspBlob = dsa.ExportCspBlob(true);
    var licenseGeneratorAndValidator = new LicenseGeneratorAndValidator(exportCspBlob, exportCspBlob);
    var licenseAttributes = JsonConvert.DeserializeObject<Dictionary<string, object>>(license);

    foreach (var key in licenseAttributes.Keys.ToArray())
    {
    var val = licenseAttributes[key] as string;
    if (val == null)
    continue;

    Guid guid;
    if (Guid.TryParse(val, out guid))
    {
    licenseAttributes[key] = guid;
    continue;
    }
    DateTime time;
    if (DateTime.TryParse(val, out time))
    {
    licenseAttributes[key] = time;
    }
    }

    var name = "Hibernating Rhinos";
    var result = licenseGeneratorAndValidator.Generate(name, licenseAttributes);
    var dictionary = licenseGeneratorAndValidator.Validate(name, result);

    Console.WriteLine(JsonConvert.SerializeObject(dictionary, Formatting.Indented));
    }
    }
    }

    public class LicenseGeneratorAndValidator
    {
    private readonly byte[] _publicKey;
    private readonly byte[] _privateKey;

    public static string[] Terms =
    {
    "id","expiration","type","version","maxRamUtilization","maxParallelism",
    "allowWindowsClustering","OEM","numberOfDatabases","fips","periodicBackup",
    "quotas","authorization","documentExpiration","replication","versioning",
    "maxSizeInGb","ravenfs","encryption","compression","updatesExpiration",
    };

    public enum ValueType : byte
    {
    False = 0,
    True = 1,
    Int = 2,
    Date = 3,
    }

    public LicenseGeneratorAndValidator(byte[] publicKey, byte[] privateKey)
    {
    if (Terms.Length > 32)
    throw new InvalidOperationException("Too many terms");

    _publicKey = publicKey;
    _privateKey = privateKey;
    }

    public static DateTime FromDosDate(ushort number)
    {
    var year = (number >> 9) + 1980;
    var month = (number & 0x01e0) >> 5;
    var day = number & 0x1F;
    return new DateTime(year, month, day);
    }

    public static ushort ToDosDateTime(DateTime dateTime)
    {
    uint day = (uint)dateTime.Day; // Between 1 and 31
    uint month = (uint)dateTime.Month; // Between 1 and 12
    uint years = (uint)(dateTime.Year - 1980); // From 1980

    if (years > 127)
    throw new ArgumentOutOfRangeException(nameof(dateTime), "Cannot represent this year.");

    uint dosDateTime = 0;
    dosDateTime |= day << (16 - 16);
    dosDateTime |= month << (21 - 16);
    dosDateTime |= years << (25 - 16);

    return unchecked((ushort)dosDateTime);
    }

    const int TypeBitsToShift = 5;

    public byte[] Generate(string name, Dictionary<string, object> attributes)
    {
    var ms = new MemoryStream();
    var bw = new BinaryWriter(ms);
    foreach (var attribute in attributes)
    {
    if (attribute.Value == null)
    throw new InvalidOperationException("Cannot write a null value");

    var index = Array.IndexOf(Terms, attribute.Key);
    if (index == -1)
    throw new InvalidOperationException("Unknown term " + attribute.Key);


    if (attribute.Value is bool)
    {
    var type = (byte)((bool)attribute.Value ? ValueType.True : ValueType.False) << TypeBitsToShift;
    bw.Write((byte)((byte)index | type));
    continue;
    }
    if (attribute.Value is DateTime)
    {
    bw.Write((byte)((byte)index | ((byte)ValueType.Date << TypeBitsToShift)));
    var dt = (DateTime)(attribute.Value);
    bw.Write(ToDosDateTime(dt));
    continue;
    }
    if (attribute.Value is int || attribute.Value is long)
    {
    var val = Convert.ToByte(attribute.Value);
    bw.Write((byte)((byte)index | ((byte)ValueType.Int << TypeBitsToShift)));
    bw.Write((byte)val);
    continue;
    }

    throw new InvalidOperationException("Cannot understand type of " + attribute.Key + " because it is " + attribute.Value.GetType().FullName);
    }

    var attributesLen = ms.Position;
    bw.Write(name);

    using (var sha1 = SHA1.Create())
    {
    ms.Position = 0;
    var hash = sha1.ComputeHash(ms);

    using (var dsa = new DSACryptoServiceProvider())
    {
    dsa.ImportCspBlob(_privateKey);


    ms.SetLength(attributesLen);
    var signature = dsa.CreateSignature(hash);
    bw.Write(signature);

    return ms.ToArray();
    }
    }
    }

    public Dictionary<string, object> Validate(string name, byte[] license)
    {
    var result = new Dictionary<string, object>();
    var ms = new MemoryStream(license);
    var br = new BinaryReader(ms);
    const int sizeOfDsaSignature = 40;
    while (ms.Position < ms.Length - sizeOfDsaSignature)
    {
    var token = ms.ReadByte();
    var index = token & 0x1F;
    object val;
    var curr = (ValueType)(token>> TypeBitsToShift);
    switch (curr)
    {
    case ValueType.False:
    val = false;
    break;
    case ValueType.True:
    val = true;
    break;
    case ValueType.Int:
    val = (int) br.ReadByte();
    break;
    case ValueType.Date:
    val = FromDosDate(br.ReadUInt16());
    break;
    default:
    throw new ArgumentOutOfRangeException();
    }

    if (index >= Terms.Length)
    continue; // new field, just skip
    result[Terms[index]] = val;
    }
    var attributesLen = ms.Position;
    var signature = br.ReadBytes(40);
    ms.SetLength(attributesLen);
    new BinaryWriter(ms).Write(name);

    using (var dsa = new DSACryptoServiceProvider())
    {
    dsa.ImportCspBlob(_publicKey);

    using (var sha1 = SHA1.Create())
    {
    ms.Position = 0;
    var hash = sha1.ComputeHash(ms);

    if (dsa.VerifySignature(hash, signature) == false)
    throw new InvalidDataException("Could not validate signature on license");
    }
    }

    return result;
    }
    }
    }
  2. ayende created this gist Feb 7, 2016.
    1 change: 1 addition & 0 deletions license-generation.cs
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1 @@
    c:\users\ayende\documents\visual studio 2015\Projects\ConsoleApplication10\ConsoleApplication10\Program.cs