apewer-dotnet/Apewer.Source/Externals/MySql.Data-6.10.9/MySqlClient/Authentication/MySQLAuthenticationPlugin.cs

#if MYSQL_6_10

// Copyright ?2012, 2018, Oracle and/or its affiliates. All rights reserved.
//
// MySQL Connector/NET is licensed under the terms of the GPLv2
// <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most 
// MySQL Connectors. There are special exceptions to the terms and 
// conditions of the GPLv2 as it is applied to this software, see the 
// FLOSS License Exception
// <http://www.mysql.com/about/legal/licensing/foss-exception.html>.
//
// This program is free software; you can redistribute it and/or modify 
// it under the terms of the GNU General Public License as published 
// by the Free Software Foundation; version 2 of the License.
//
// This program is distributed in the hope that it will be useful, but 
// WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 
// for more details.
//
// You should have received a copy of the GNU General Public License along 
// with this program; if not, write to the Free Software Foundation, Inc., 
// 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA

using System;
using System.Diagnostics;
using System.Text;
using Externals.MySql.Data.MySqlClient;


namespace Externals.MySql.Data.MySqlClient.Authentication
{
    /// <summary>
    /// Defines the default behavior for an authentication plugin.
    /// </summary>
    internal abstract class MySqlAuthenticationPlugin
    {
        private NativeDriver _driver;

        /// <summary>
        /// Gets or sets the authentication data returned by the server.
        /// </summary>
        protected byte[] AuthenticationData;

        /// <summary>
        /// This is a factory method that is used only internally.  It creates an auth plugin based on the method type
        /// </summary>
        /// <param name="method"></param>
        /// <param name="driver"></param>
        /// <param name="authData"></param>
        /// <returns></returns>
        internal static MySqlAuthenticationPlugin GetPlugin(string method, NativeDriver driver, byte[] authData)
        {
            if (method == "mysql_old_password")
            {
                driver.Close(true);
                throw new MySqlException(Resources.OldPasswordsNotSupported);
            }
            MySqlAuthenticationPlugin plugin = AuthenticationPluginManager.GetPlugin(method);
            if (plugin == null)
                throw new MySqlException(String.Format(Resources.UnknownAuthenticationMethod, method));

            plugin._driver = driver;
            plugin.SetAuthData(authData);
            return plugin;
        }

        /// <summary>
        /// Gets the connection option settings.
        /// </summary>
        protected MySqlConnectionStringBuilder Settings => _driver.Settings;

        /// <summary>
        /// Gets the server version associated with this authentication plugin.
        /// </summary>
        protected Version ServerVersion => new Version(_driver.Version.Major, _driver.Version.Minor, _driver.Version.Build);

        internal ClientFlags Flags => _driver.Flags;

        /// <summary>
        /// Gets the encoding assigned to the native driver.
        /// </summary>
        protected Encoding Encoding => _driver.Encoding;

        /// <summary>
        /// Sets the authentication data required to encode, encrypt, or convert the password of the user.
        /// </summary>
        /// <param name="data">A byte array containing the authentication data provided by the server.</param>
        /// <remarks>This method may be overriden based on the requirements by the implementing authentication plugin.</remarks>
        protected virtual void SetAuthData(byte[] data)
        {
            AuthenticationData = data;
        }

        /// <summary>
        /// Defines the behavior when checking for constraints.
        /// </summary>
        /// <remarks>This method is intended to be overriden.</remarks>
        protected virtual void CheckConstraints()
        {
        }

        /// <summary>
        /// Throws a <see cref="MySqlException"/> that encapsulates the original exception.
        /// </summary>
        /// <param name="ex">The exception to encapsulate.</param>
        protected virtual void AuthenticationFailed(Exception ex)
        {
            string msg = String.Format(Resources.AuthenticationFailed, Settings.Server, GetUsername(), PluginName, ex.Message);
            throw new MySqlException(msg, ex);
        }

        /// <summary>
        /// Defines the behavior when authentication is successful.
        /// </summary>
        /// <remarks>This method is intended to be overriden.</remarks>
        protected virtual void AuthenticationSuccessful()
        {
        }

        /// <summary>
        /// Defines the behavior when more data is required from the server.
        /// </summary>
        /// <param name="data">The data returned by the server.</param>
        /// <returns>The data to return to the server.</returns>
        /// <remarks>This method is intended to be overriden.</remarks>
        protected virtual byte[] MoreData(byte[] data)
        {
            return null;
        }

        internal void Authenticate(bool reset)
        {
            CheckConstraints();

            MySqlPacket packet = _driver.Packet;

            // send auth response
            packet.WriteString(GetUsername());

            // now write the password
            WritePassword(packet);

            if ((Flags & ClientFlags.CONNECT_WITH_DB) != 0 || reset)
            {
                if (!String.IsNullOrEmpty(Settings.Database))
                    packet.WriteString(Settings.Database);
            }

            if (reset)
                packet.WriteInteger(8, 2);

            if ((Flags & ClientFlags.PLUGIN_AUTH) != 0)
                packet.WriteString(PluginName);

            _driver.SetConnectAttrs();
            _driver.SendPacket(packet);

            // Read server response.
            packet = ReadPacket();
            byte[] b = packet.Buffer;

            if (PluginName == "caching_sha2_password" && b[0] == 0x01)
            {
                // React to the authentication type set by server: FAST, FULL.
                ContinueAuthentication(new byte[] { b[1] });
            }

            // Auth switch request Protocol::AuthSwitchRequest.
            if (b[0] == 0xfe)
            {
                if (packet.IsLastPacket)
                {
                    _driver.Close(true);
                    throw new MySqlException(Resources.OldPasswordsNotSupported);
                }
                else
                {
                    HandleAuthChange(packet);
                }
            }
            _driver.ReadOk(false);
            AuthenticationSuccessful();
        }

        private void WritePassword(MySqlPacket packet)
        {
            bool secure = (Flags & ClientFlags.SECURE_CONNECTION) != 0;
            object password = GetPassword();
            if (password is string)
            {
                if (secure)
                    packet.WriteLenString((string)password);
                else
                    packet.WriteString((string)password);
            }
            else if (password == null)
                packet.WriteByte(0);
            else if (password is byte[])
                packet.Write(password as byte[]);
            else throw new MySqlException("Unexpected password format: " + password.GetType());
        }

        private MySqlPacket ReadPacket()
        {
            try
            {
                MySqlPacket p = _driver.ReadPacket();
                return p;
            }
            catch (MySqlException ex)
            {
                // Make sure this is an auth failed ex.
                AuthenticationFailed(ex);
                return null;
            }
        }

        private void HandleAuthChange(MySqlPacket packet)
        {
            byte b = packet.ReadByte();
            Debug.Assert(b == 0xfe);

            string method = packet.ReadString();
            byte[] authData = new byte[packet.Length - packet.Position];
            Array.Copy(packet.Buffer, packet.Position, authData, 0, authData.Length);

            MySqlAuthenticationPlugin plugin = GetPlugin(method, _driver, authData);
            plugin.ContinueAuthentication();
        }

        private void ContinueAuthentication(byte[] data = null)
        {
            MySqlPacket packet = _driver.Packet;
            packet.Clear();
            byte[] moreData = MoreData(data);

            while (moreData != null)
            {
                packet.Clear();
                packet.Write(moreData);
                _driver.SendPacket(packet);

                packet = ReadPacket();
                byte prefixByte = packet.Buffer[0];
                if (prefixByte != 1) return;

                // A prefix of 0x01 means need more auth data.
                byte[] responseData = new byte[packet.Length - 1];
                Array.Copy(packet.Buffer, 1, responseData, 0, responseData.Length);
                moreData = MoreData(responseData);
            }
            // We get here if MoreData returned null but the last packet read was a more data packet.
            ReadPacket();
        }

        /// <summary>
        /// Gets the plugin name based on the authentication plugin type defined during the creation of this object.
        /// </summary>
        public abstract string PluginName { get; }

        /// <summary>
        /// Gets the user name associated to the connection settings.
        /// </summary>
        /// <returns>The user name associated to the connection settings.</returns>
        public virtual string GetUsername()
        {
            return Settings.UserID;
        }

        /// <summary>
        /// Gets the encoded, encrypted, or converted password based on the authentication plugin type defined during the creation of this object.
        /// This method is intended to be overriden.
        /// </summary>
        /// <returns>An object containing the encoded, encrypted, or converted password.</returns>
        public virtual object GetPassword()
        {
            return null;
        }
    }
}

#endif