SignatureAuthManager.cs

/*==============================================================================
Copyright 2017 Maxst, Inc. All Rights Reserved.
==============================================================================*/

using UnityEngine;
using System.Collections;
using System.IO;
using System.Runtime.InteropServices;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System;
using System.Xml;

/*
 * This class should be run Windows runtime and Mac runtime only (Should not call in Editor mode)
 */
namespace maxstAR
{
    public class SignatureAuthManager
    {

        private static SignatureAuthManager instance = null;

        public static SignatureAuthManager getInstance()
        {
            if (instance == null)
            {
                instance = new SignatureAuthManager();
            }

            return instance;
        }

        private const int SIGNATURE_MAX_LEN = 128;
        private const string APP_SIGNATURE_FILE_NAME = "ApplicationSignature.xml";

        private string applicationId;

        /* 
         * Create current application id as hash string.
         * If ApplicationSignature.xml file does not exist create that file and set current application Id.
         * Read xml file and extract application id.
         * If app id is not same set application id and delete signature.
         * Save xml string to ApplicationSignature.xml file. 
         */
        public void setAppIdAndSignature()
        {
            makeAppIdFromAssemblyDll();
            createSignatureFileIfNeeded();
            resetAppIdAndSignature();
            setSignatureFromFile();
        }

        private void makeAppIdFromAssemblyDll()
        {
            string assemblyFilePath = null;

            if (Application.platform == RuntimePlatform.WindowsPlayer)
            {
                assemblyFilePath = Application.dataPath + "/Managed/" + "Assembly-CSharp.dll";
            }
            else if (Application.platform == RuntimePlatform.OSXPlayer)
            {
                assemblyFilePath = Application.dataPath + "/Resources/Data/Managed/" + "Assembly-CSharp.dll";
            }

            // Read Assembly-CSharp.dll file
            FileStream assemblyFS = File.Open(assemblyFilePath, FileMode.Open);
            byte[] assemblyBytes = new byte[1024];
            assemblyFS.Read(assemblyBytes, 0, assemblyBytes.Length);
            assemblyFS.Close();

            int size = Marshal.SizeOf(assemblyBytes[0]) * assemblyBytes.Length;

            IntPtr unmanagedArrayPtr = Marshal.AllocHGlobal(size);

            try
            {
                // Copy the array to unmanaged memory.
                Marshal.Copy(assemblyBytes, 0, unmanagedArrayPtr, assemblyBytes.Length);
            }
            finally
            {

            }

            byte[] appIdBytes = Enumerable.Repeat((byte)0x00, SIGNATURE_MAX_LEN).ToArray();
            int[] appIdLength = new int[1];

            // Use common hash function of native dll
            // TODO : Block PC version signature authentication
            //MaxstARAPI.createAppId(unmanagedArrayPtr, assemblyBytes.Length, appIdBytes, appIdLength);

            byte[] newAppIdBytes = new byte[appIdLength[0]];

            Array.Copy(appIdBytes, newAppIdBytes, appIdLength[0]);

            applicationId = Encoding.Default.GetString(newAppIdBytes);

            Marshal.FreeHGlobal(unmanagedArrayPtr);
        }

        private void createSignatureFileIfNeeded()
        {
            if (!File.Exists(Directory.GetCurrentDirectory() + "/" + APP_SIGNATURE_FILE_NAME))
            {
                XmlDocument doc = new XmlDocument();
                XmlNode docNode = doc.CreateXmlDeclaration("1.0", "UTF-8", null);
                doc.AppendChild(docNode);

                XmlNode rootNode = doc.CreateElement("MaxstARSDK");
                doc.AppendChild(rootNode);

                XmlNode appIdElement = doc.CreateElement("AppId");
                appIdElement.InnerText = applicationId;
                rootNode.AppendChild(appIdElement);

                XmlNode appSigElement = doc.CreateElement("AppSignature");
                appSigElement.InnerText = "_Invalid_Signature_";
                rootNode.AppendChild(appSigElement);

                doc.Save(Directory.GetCurrentDirectory() + "/" + APP_SIGNATURE_FILE_NAME);
            }
        }

        private void resetAppIdAndSignature()
        {
            XmlDocument xmldoc = new XmlDocument();
            xmldoc.Load(Directory.GetCurrentDirectory() + "/" + APP_SIGNATURE_FILE_NAME);
            XmlElement docRoot = xmldoc.DocumentElement;

            XmlNode appIdNode = docRoot.SelectSingleNode("AppId");
            XmlNode appSigNode = docRoot.SelectSingleNode("AppSignature");

            string previousAppId = appIdNode.InnerText;

            if (String.Compare(previousAppId, applicationId) != 0)
            {
                appIdNode.InnerText = applicationId;
                appSigNode.InnerText = "_Invalid_Signature_";
                xmldoc.Save(Directory.GetCurrentDirectory() + "/" + APP_SIGNATURE_FILE_NAME);
            }
        }

        private void setSignatureFromFile()
        {
            XmlDocument xmldoc = new XmlDocument();
            xmldoc.Load(Directory.GetCurrentDirectory() + "/" + APP_SIGNATURE_FILE_NAME);
            XmlElement docRoot = xmldoc.DocumentElement;

            XmlNode appIdNode = docRoot.SelectSingleNode("AppId");
            XmlNode appSigNode = docRoot.SelectSingleNode("AppSignature");

            string signature = appSigNode.InnerText;
            if (signature != null && signature.Length > 0)
            {
                // Pass app signature to native dll
                // TODO : Block PC version signature authentication
                //MaxstARAPI.SetAppSignature(signature);
            }
        }
    }
}