Exposes SSL Stream and adds more TLS settings (#132)

Motivation:

Some important SSL Stream settings are hidden in the TlsHandler class

Modifications:
SSLStream is provided by user now via factory method;
TLS settings extended

Results:
More advanced scenarios, like X509 client authentication, are possible to do now

examples/Echo.Client/Program.cs

@@ -6,6 +6,7 @@ namespace Echo.Client
     using System;
     using System.Diagnostics.Tracing;
     using System.Net;
+    using System.Net.Security;
     using System.Security.Cryptography.X509Certificates;
     using System.Threading.Tasks;
     using DotNetty.Codecs;
@@ -26,6 +27,13 @@ static async Task RunClientAsync()
 
             var group = new MultithreadEventLoopGroup();
 
+            X509Certificate2 cert = null;
+            string targetHost = null;
+            if (EchoClientSettings.IsSsl)
+            {
+                cert = new X509Certificate2("dotnetty.com.pfx", "password");
+                targetHost = cert.GetNameInfo(X509NameType.DnsName, false);
+            }
             try
             {
                 var bootstrap = new Bootstrap();
@@ -37,11 +45,9 @@ static async Task RunClientAsync()
                     {
                         IChannelPipeline pipeline = channel.Pipeline;
 
-                        if (EchoClientSettings.IsSsl)
+                        if (cert != null)
                         {
-                            var cert = new X509Certificate2("dotnetty.com.pfx", "password");
-                            string targetHost = cert.GetNameInfo(X509NameType.DnsName, false);
-                            pipeline.AddLast(TlsHandler.Client(targetHost, null, (sender, certificate, chain, errors) => true));
+                            pipeline.AddLast(new TlsHandler(stream => new SslStream(stream, true, (sender, certificate, chain, errors) => true), new ClientTlsSettings(targetHost)));
                         }
                         pipeline.AddLast(new LengthFieldPrepender(2));
                         pipeline.AddLast(new LengthFieldBasedFrameDecoder(ushort.MaxValue, 0, 2, 0, 2));

examples/Echo.Server/Program.cs

@@ -5,6 +5,7 @@ namespace Echo.Server
 {
     using System;
     using System.Diagnostics.Tracing;
+    using System.Net.Security;
     using System.Security.Cryptography.X509Certificates;
     using System.Threading.Tasks;
     using DotNetty.Codecs;
@@ -26,6 +27,11 @@ static async Task RunServerAsync()
 
             var bossGroup = new MultithreadEventLoopGroup(1);
             var workerGroup = new MultithreadEventLoopGroup();
+            X509Certificate2 tlsCertificate = null;
+            if (EchoServerSettings.IsSsl)
+            {
+                tlsCertificate = new X509Certificate2("dotnetty.com.pfx", "password");
+            }
             try
             {
                 var bootstrap = new ServerBootstrap();
@@ -37,10 +43,9 @@ static async Task RunServerAsync()
                     .ChildHandler(new ActionChannelInitializer<ISocketChannel>(channel =>
                     {
                         IChannelPipeline pipeline = channel.Pipeline;
-
-                        if (EchoServerSettings.IsSsl)
+                        if (tlsCertificate != null)
                         {
-                            pipeline.AddLast(TlsHandler.Server(new X509Certificate2("dotnetty.com.pfx", "password")));
+                            pipeline.AddLast(TlsHandler.Server(tlsCertificate));
                         }
                         pipeline.AddLast(new LengthFieldPrepender(2));
                         pipeline.AddLast(new LengthFieldBasedFrameDecoder(ushort.MaxValue, 0, 2, 0, 2));

src/DotNetty.Handlers/DotNetty.Handlers.csproj

@@ -47,7 +47,9 @@
     <Compile Include="Logging\LogLevel.cs" />
     <Compile Include="Logging\LogLevelExtensions.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="Tls\ClientTlsSettings.cs" />
     <Compile Include="Tls\NotSslRecordException.cs" />
+    <Compile Include="Tls\ServerTlsSettings.cs" />
     <Compile Include="Tls\TlsHandshakeCompletionEvent.cs" />
     <Compile Include="Tls\TlsHandler.cs" />
     <Compile Include="Timeout\IdleState.cs" />
@@ -58,6 +60,7 @@
     <Compile Include="Timeout\WriteTimeoutException.cs" />
     <Compile Include="Timeout\ReadTimeoutHandler.cs" />
     <Compile Include="Timeout\WriteTimeoutHandler.cs" />
+    <Compile Include="Tls\TlsSettings.cs" />
     <Compile Include="Tls\TlsUtils.cs" />
   </ItemGroup>
   <ItemGroup>

src/DotNetty.Handlers/Tls/ClientTlsSettings.cs

@@ -0,0 +1,44 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+namespace DotNetty.Handlers.Tls
+{
+    using System.Collections.Generic;
+    using System.Linq;
+    using System.Security.Authentication;
+    using System.Security.Cryptography.X509Certificates;
+
+    public sealed class ClientTlsSettings : TlsSettings
+    {
+        IReadOnlyCollection<X509Certificate2> certificates;
+
+        public ClientTlsSettings(string targetHost)
+            : this(targetHost, new List<X509Certificate>())
+        {
+        }
+
+        public ClientTlsSettings(string targetHost, List<X509Certificate> certificates)
+            : this(false, certificates, targetHost)
+        {
+        }
+
+        public ClientTlsSettings(bool checkCertificateRevocation, List<X509Certificate> certificates, string targetHost)
+            : this(SslProtocols.Tls | SslProtocols.Tls11 | SslProtocols.Tls12, checkCertificateRevocation, certificates, targetHost)
+        {
+        }
+
+        public ClientTlsSettings(SslProtocols enabledProtocols, bool checkCertificateRevocation, List<X509Certificate> certificates, string targetHost)
+            :base(enabledProtocols, checkCertificateRevocation)
+        {
+            this.X509CertificateCollection = new X509CertificateCollection(certificates.ToArray());
+            this.TargetHost = targetHost;
+            this.Certificates = certificates.AsReadOnly();
+        }
+
+        internal X509CertificateCollection X509CertificateCollection { get; set; }
+
+        public IReadOnlyCollection<X509Certificate> Certificates { get; }
+
+        public string TargetHost { get; }
+    }
+}

src/DotNetty.Handlers/Tls/ServerTlsSettings.cs

@@ -0,0 +1,29 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+namespace DotNetty.Handlers.Tls
+{
+    using System.Security.Authentication;
+    using System.Security.Cryptography.X509Certificates;
+
+    public sealed class ServerTlsSettings : TlsSettings
+    {
+        public ServerTlsSettings(X509Certificate certificate)
+            : this(false, certificate)
+        {
+        }
+
+        public ServerTlsSettings(bool checkCertificateRevocation, X509Certificate certificate)
+            : this(SslProtocols.Tls | SslProtocols.Tls11 | SslProtocols.Tls12, checkCertificateRevocation, certificate)
+        {
+        }
+
+        public ServerTlsSettings(SslProtocols enabledProtocols, bool checkCertificateRevocation, X509Certificate certificate)
+            : base(enabledProtocols, checkCertificateRevocation)
+        {
+            this.Certificate = certificate;
+        }
+
+        public X509Certificate Certificate { get; }
+    }
+}

src/DotNetty.Handlers/Tls/TlsHandler.cs

@@ -9,7 +9,6 @@ namespace DotNetty.Handlers.Tls
     using System.IO;
     using System.Net.Security;
     using System.Runtime.ExceptionServices;
-    using System.Security.Authentication;
     using System.Security.Cryptography.X509Certificates;
     using System.Threading;
     using System.Threading.Tasks;
@@ -21,48 +20,47 @@ namespace DotNetty.Handlers.Tls
 
     public sealed class TlsHandler : ByteToMessageDecoder
     {
+        readonly TlsSettings settings;
         const int FallbackReadBufferSize = 256;
         const int UnencryptedWriteBatchSize = 14 * 1024;
 
         static readonly Exception ChannelClosedException = new IOException("Channel is closed");
         static readonly Action<Task, object> HandshakeCompletionCallback = new Action<Task, object>(HandleHandshakeCompleted);
 
         readonly SslStream sslStream;
+        readonly MediationStream mediationStream;
+        readonly TaskCompletionSource closeFuture;
+
         TlsHandlerState state;
         int packetLength;
-        readonly MediationStream mediationStream;
         volatile IChannelHandlerContext capturedContext;
         BatchingPendingWriteQueue pendingUnencryptedWrites;
         Task lastContextWriteTask;
-        readonly TaskCompletionSource closeFuture;
-        readonly bool isServer;
-        readonly X509Certificate2 certificate;
-        readonly string targetHost;
         bool firedChannelRead;
         IByteBuffer pendingSslStreamReadBuffer;
         Task<int> pendingSslStreamReadFuture;
 
-        TlsHandler(bool isServer, X509Certificate2 certificate, string targetHost, RemoteCertificateValidationCallback certificateValidationCallback)
+        public TlsHandler(TlsSettings settings)
+            : this(stream => new SslStream(stream, true), settings)
         {
-            Contract.Requires(!isServer || certificate != null);
-            Contract.Requires(isServer || !string.IsNullOrEmpty(targetHost));
+        }
 
-            this.closeFuture = new TaskCompletionSource();
+        public TlsHandler(Func<Stream, SslStream> sslStreamFactory, TlsSettings settings)
+        {
+            Contract.Requires(sslStreamFactory != null);
+            Contract.Requires(settings != null);
 
-            this.isServer = isServer;
-            this.certificate = certificate;
-            this.targetHost = targetHost;
+            this.settings = settings;
+            this.closeFuture = new TaskCompletionSource();
             this.mediationStream = new MediationStream(this);
-            this.sslStream = new SslStream(this.mediationStream, true, certificateValidationCallback);
+            this.sslStream = sslStreamFactory(this.mediationStream);
         }
 
-        public static TlsHandler Client(string targetHost) => new TlsHandler(false, null, targetHost, null);
-
-        public static TlsHandler Client(string targetHost, X509Certificate2 certificate) => new TlsHandler(false, certificate, targetHost, null);
+        public static TlsHandler Client(string targetHost) => new TlsHandler(new ClientTlsSettings(targetHost));
 
-        public static TlsHandler Client(string targetHost, X509Certificate2 certificate, RemoteCertificateValidationCallback certificateValidationCallback) => new TlsHandler(false, certificate, targetHost, certificateValidationCallback);
-
-        public static TlsHandler Server(X509Certificate2 certificate) => new TlsHandler(true, certificate, null, null);
+        public static TlsHandler Client(string targetHost, X509Certificate clientCertificate) => new TlsHandler(new ClientTlsSettings(targetHost, new List<X509Certificate>{ clientCertificate }));
+ 
+        public static TlsHandler Server(X509Certificate certificate) => new TlsHandler(new ServerTlsSettings(certificate));
 
         public X509Certificate LocalCertificate => this.sslStream.LocalCertificate;
 
@@ -74,7 +72,7 @@ public override void ChannelActive(IChannelHandlerContext context)
         {
             base.ChannelActive(context);
 
-            if (!this.isServer)
+            if (this.settings is ServerTlsSettings)
             {
                 this.EnsureAuthenticated();
             }
@@ -161,7 +159,7 @@ public override void HandlerAdded(IChannelHandlerContext context)
             base.HandlerAdded(context);
             this.capturedContext = context;
             this.pendingUnencryptedWrites = new BatchingPendingWriteQueue(context, UnencryptedWriteBatchSize);
-            if (context.Channel.Active && !this.isServer)
+            if (context.Channel.Active && this.settings is ClientTlsSettings)
             {
                 // todo: support delayed initialization on an existing/active channel if in client mode
                 this.EnsureAuthenticated();
@@ -217,23 +215,23 @@ protected override void Decode(IChannelHandlerContext context, IByteBuffer input
                     break;
                 }
 
-                int packetLength = TlsUtils.GetEncryptedPacketLength(input, offset);
-                if (packetLength == -1)
+                int encryptedPacketLength = TlsUtils.GetEncryptedPacketLength(input, offset);
+                if (encryptedPacketLength == -1)
                 {
                     nonSslRecord = true;
                     break;
                 }
 
-                Contract.Assert(packetLength > 0);
+                Contract.Assert(encryptedPacketLength > 0);
 
-                if (packetLength > readableBytes)
+                if (encryptedPacketLength > readableBytes)
                 {
                     // wait until the whole packet can be read
-                    this.packetLength = packetLength;
+                    this.packetLength = encryptedPacketLength;
                     break;
                 }
 
-                int newTotalLength = totalLength + packetLength;
+                int newTotalLength = totalLength + encryptedPacketLength;
                 if (newTotalLength > TlsUtils.MAX_ENCRYPTED_PACKET_LENGTH)
                 {
                     // Don't read too much.
@@ -245,8 +243,8 @@ protected override void Decode(IChannelHandlerContext context, IByteBuffer input
 
                 // We have a whole packet.
                 // Increment the offset to handle the next packet.
-                packetLengths.Add(packetLength);
-                offset += packetLength;
+                packetLengths.Add(encryptedPacketLength);
+                offset += encryptedPacketLength;
                 totalLength = newTotalLength;
             }
 
@@ -482,19 +480,16 @@ bool EnsureAuthenticated()
             if (!oldState.HasAny(TlsHandlerState.AuthenticationStarted))
             {
                 this.state = oldState | TlsHandlerState.Authenticating;
-                if (this.isServer)
+                var serverSettings = settings as ServerTlsSettings;
+                if (serverSettings != null)
                 {
-                    this.sslStream.AuthenticateAsServerAsync(this.certificate, false, SslProtocols.Tls | SslProtocols.Tls11 | SslProtocols.Tls12, false) // todo: change to begin/end
+                    this.sslStream.AuthenticateAsServerAsync(serverSettings.Certificate, false, serverSettings.EnabledProtocols, serverSettings.CheckCertificateRevocation)
                         .ContinueWith(HandshakeCompletionCallback, this, TaskContinuationOptions.ExecuteSynchronously);
                 }
                 else
                 {
-                    var certificateCollection = new X509Certificate2Collection();
-                    if (this.certificate != null)
-                    {
-                        certificateCollection.Add(this.certificate);
-                    }
-                    this.sslStream.AuthenticateAsClientAsync(this.targetHost, certificateCollection, SslProtocols.Tls | SslProtocols.Tls11 | SslProtocols.Tls12, false) // todo: change to begin/end
+                    var clientSettings = (ClientTlsSettings)settings;
+                    this.sslStream.AuthenticateAsClientAsync(clientSettings.TargetHost, clientSettings.X509CertificateCollection, clientSettings.EnabledProtocols, clientSettings.CheckCertificateRevocation)
                         .ContinueWith(HandshakeCompletionCallback, this, TaskContinuationOptions.ExecuteSynchronously);
                 }
                 return false;

src/DotNetty.Handlers/Tls/TlsSettings.cs

@@ -0,0 +1,20 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+namespace DotNetty.Handlers.Tls
+{
+    using System.Security.Authentication;
+
+    public abstract class TlsSettings
+    {
+        protected TlsSettings(SslProtocols enabledProtocols, bool checkCertificateRevocation)
+        {
+            this.EnabledProtocols = enabledProtocols;
+            this.CheckCertificateRevocation = checkCertificateRevocation;
+        }
+
+        public SslProtocols EnabledProtocols { get; }
+
+        public bool CheckCertificateRevocation { get; }
+    }
+}

test/DotNetty.Handlers.Tests/TlsHandlerTest.cs

@@ -154,7 +154,9 @@ static async Task<Tuple<EmbeddedChannel, SslStream>> SetupStreamAndChannelAsync(
         {
             var tlsCertificate = new X509Certificate2("dotnetty.com.pfx", "password");
             string targetHost = tlsCertificate.GetNameInfo(X509NameType.DnsName, false);
-            TlsHandler tlsHandler = isClient ? TlsHandler.Client(targetHost, null, (_1, _2, _3, _4) => true) : TlsHandler.Server(tlsCertificate);
+            TlsHandler tlsHandler = isClient ? 
+                new TlsHandler(stream => new SslStream(stream, true, (sender, certificate, chain, errors) => true), new ClientTlsSettings(targetHost)) : 
+                TlsHandler.Server(tlsCertificate);
             //var ch = new EmbeddedChannel(new LoggingHandler("BEFORE"), tlsHandler, new LoggingHandler("AFTER"));
             var ch = new EmbeddedChannel(tlsHandler);