JD2022-TU1/main/tools/services/JD.Oasis.Service/Implementation/CredentialsManager.cs

using System;
using System.IO;
using JD.Oasis.Service.API;
using System.Net;
using System.Security.Cryptography;
using System.Text;
using Newtonsoft.Json;

namespace JD.Oasis.Service.Implementation
{
    /// <summary>
    /// Will store/retrieve alternative credentials for Oasis Web Service from a local file
    /// or in case the file is not yer created, it will ask the caller to provide a set of credentials
    /// using the getCredentials function
    /// </summary>
    public class CredentialsManager : ICredentialsManager
    {
        private readonly Func<Tuple<string, string>> _getCredentialsFunc;

        // Random generated entropy to secure the storage of the credentials on Windows
        private static readonly byte[] Entropy =
            {165, 55, 145, 89, 198, 64, 173, 97, 65, 167, 166, 17, 61, 186, 161, 51, 84, 219, 177, 211};
        
        private const string LOGIN_FILE_NAME = @"oasiswebservicelogin.json";

        private string _loginFilePath;
        public string LoginFilePath
        {
            get
            {
                if (_loginFilePath == null)
                {
                    // Default is under Ubisoft App Data folder
                    _loginFilePath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "Ubisoft", LOGIN_FILE_NAME);
                }

                return _loginFilePath;
            }
            set => _loginFilePath = value;
        }

        public CredentialsManager(Func<Tuple<string, string>> getCredentialsFunc)
        {
            _getCredentialsFunc = getCredentialsFunc ?? throw new ArgumentNullException(nameof(getCredentialsFunc));
        }

        /// <inheritdoc />
        public bool UseAltCredentials => GetLocalLogin() != null;

        /// <inheritdoc />
        public bool TryGetStoredAltCredentials(out NetworkCredential networkCredential)
        {
            networkCredential = null;

            // First we try to see if there is any local alternative login already set
            ServiceLogin localLogin = GetLocalLogin();

            if (localLogin != null)
            {
                // A local login is present, we decrypt the password and use those credentials

                byte[] pwBytes = ProtectedData.Unprotect(localLogin.Password, Entropy, DataProtectionScope.CurrentUser);

                networkCredential = new NetworkCredential(localLogin.Username, Encoding.Unicode.GetString(pwBytes));

                return true;
            }

            return false;
        }

        /// <inheritdoc />
        public bool TryAskAltCredentials(out NetworkCredential networkCredential)
        {
            networkCredential = null;

            // no local login, we run the function to fetch the credentials
            Tuple<string, string> credentials = _getCredentialsFunc();

            if (credentials != null &&
                credentials.Item1 != null && credentials.Item2 != null)
            {
                networkCredential = new NetworkCredential(credentials.Item1, credentials.Item2);

                return true;
            }
            
            return false;
        }

        /// <inheritdoc />
        public void StoreAltCredentials(string username,  string password)
        {
            if (string.IsNullOrEmpty(password))
                throw new ArgumentException("Value cannot be null or empty.", nameof(password));
            if (string.IsNullOrEmpty(username))
                throw new ArgumentException("Value cannot be null or empty.", nameof(username));

            // Data to protect. Convert a string to a byte[] using Unicode encoding.
            byte[] plaintext = Encoding.Unicode.GetBytes(password);

            // Encrypt the password using Windows private keys
            byte[] ciphertext = ProtectedData.Protect(plaintext, Entropy, DataProtectionScope.CurrentUser);

            // serialize ciphertext
            string serializedLogin = JsonConvert.SerializeObject(new ServiceLogin {Username = username, Password = ciphertext},
                Formatting.Indented);

            File.WriteAllText(LoginFilePath, serializedLogin);
        }

        private ServiceLogin GetLocalLogin()
        {
            // if file does not exist, there is no local login
            if (!File.Exists(LoginFilePath))
            {
                return null;
            }

            try
            {
                ServiceLogin login = JsonConvert.DeserializeObject<ServiceLogin>(File.ReadAllText(LoginFilePath));

                return login;
            }
            catch (Exception)
            {
                // file is unreadable
                return null;
            }
        }
    }

    public class ServiceLogin
    {
        [JsonProperty("username", Required = Required.Always)]
        public string Username { get; set; }

        [JsonProperty("password", Required = Required.Always)]
        public byte[] Password { get; set; }
    }
}