Improve implementation of IHttpUpgradeFeature

After upgrade has been accepted by the server:
 - Reads to HttpRequest.Body always return 0
 - Writes to HttpResponse.Body always throw
 - The only valid way to communicate is to use the stream returned by IHttpUpgradeFeature.UpgradeAsync()

Also, Kestrel returns HTTP 400 if requests attempt to send a request body along with Connection: Upgrade

.gitignore

@@ -4,6 +4,7 @@ TestResults/
 .nuget/
 *.sln.ide/
 _ReSharper.*/
+.idea/
 packages/
 artifacts/
 PublishProfiles/

src/Microsoft.AspNetCore.Server.Kestrel.Core/BadHttpRequestException.cs

@@ -89,6 +89,9 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core
                 case RequestRejectionReason.InvalidHostHeader:
                     ex = new BadHttpRequestException("Invalid Host header.", StatusCodes.Status400BadRequest);
                     break;
+                case RequestRejectionReason.UpgradeRequestCannotHavePayload:
+                    ex = new BadHttpRequestException("Requests with 'Connection: Upgrade' cannot have content in the request body.", StatusCodes.Status400BadRequest);
+                    break;
                 default:
                     ex = new BadHttpRequestException("Bad request.", StatusCodes.Status400BadRequest);
                     break;

src/Microsoft.AspNetCore.Server.Kestrel.Core/CoreStrings.resx

@@ -0,0 +1,123 @@
+<?xml version="1.0" encoding="utf-8"?>
+<root>
+  <!-- 
+    Microsoft ResX Schema 
+    
+    Version 2.0
+    
+    The primary goals of this format is to allow a simple XML format 
+    that is mostly human readable. The generation and parsing of the 
+    various data types are done through the TypeConverter classes 
+    associated with the data types.
+    
+    Example:
+    
+    ... ado.net/XML headers & schema ...
+    <resheader name="resmimetype">text/microsoft-resx</resheader>
+    <resheader name="version">2.0</resheader>
+    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
+    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
+    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
+    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
+    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
+        <value>[base64 mime encoded serialized .NET Framework object]</value>
+    </data>
+    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
+        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
+        <comment>This is a comment</comment>
+    </data>
+                
+    There are any number of "resheader" rows that contain simple 
+    name/value pairs.
+    
+    Each data row contains a name, and value. The row also contains a 
+    type or mimetype. Type corresponds to a .NET class that support 
+    text/value conversion through the TypeConverter architecture. 
+    Classes that don't support this are serialized and stored with the 
+    mimetype set.
+    
+    The mimetype is used for serialized objects, and tells the 
+    ResXResourceReader how to depersist the object. This is currently not 
+    extensible. For a given mimetype the value must be set accordingly:
+    
+    Note - application/x-microsoft.net.object.binary.base64 is the format 
+    that the ResXResourceWriter will generate, however the reader can 
+    read any of the formats listed below.
+    
+    mimetype: application/x-microsoft.net.object.binary.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
+            : and then encoded with base64 encoding.
+    
+    mimetype: application/x-microsoft.net.object.soap.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
+            : and then encoded with base64 encoding.
+
+    mimetype: application/x-microsoft.net.object.bytearray.base64
+    value   : The object must be serialized into a byte array 
+            : using a System.ComponentModel.TypeConverter
+            : and then encoded with base64 encoding.
+    -->
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <data name="ResponseStreamWasUpgraded" xml:space="preserve">
+    <value>Cannot write to response body after connection has been upgraded.</value>
+  </data>
+</root>

src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/Frame.FeatureCollection.cs

@@ -244,7 +244,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
 
             await FlushAsync(default(CancellationToken));
 
-            return DuplexStream;
+            return _frameStreams.Upgrade();
         }
 
         IEnumerator<KeyValuePair<Type, object>> IEnumerable<KeyValuePair<Type, object>>.GetEnumerator() => FastEnumerable().GetEnumerator();

src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/Frame.cs

@@ -241,8 +241,6 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
         public IHeaderDictionary ResponseHeaders { get; set; }
         public Stream ResponseBody { get; set; }
 
-        public Stream DuplexStream { get; set; }
-
         public CancellationToken RequestAborted
         {
             get
@@ -323,31 +321,14 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
                 _frameStreams = new Streams(this);
             }
 
-            RequestBody = _frameStreams.RequestBody;
+            (RequestBody, ResponseBody) = _frameStreams.Start(messageBody);
-            ResponseBody = _frameStreams.ResponseBody;
-            DuplexStream = _frameStreams.DuplexStream;
-
-            _frameStreams.RequestBody.StartAcceptingReads(messageBody);
-            _frameStreams.ResponseBody.StartAcceptingWrites();
         }
 
-        public void PauseStreams()
+        public void PauseStreams() => _frameStreams.Pause();
-        {
-            _frameStreams.RequestBody.PauseAcceptingReads();
-            _frameStreams.ResponseBody.PauseAcceptingWrites();
-        }
 
-        public void ResumeStreams()
+        public void ResumeStreams() => _frameStreams.Resume();
-        {
-            _frameStreams.RequestBody.ResumeAcceptingReads();
-            _frameStreams.ResponseBody.ResumeAcceptingWrites();
-        }
 
-        public void StopStreams()
+        public void StopStreams() => _frameStreams.Stop();
-        {
-            _frameStreams.RequestBody.StopAcceptingReads();
-            _frameStreams.ResponseBody.StopAcceptingWrites();
-        }
 
         public void Reset()
         {
@@ -455,8 +436,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             {
                 _requestProcessingStopping = true;
 
-                _frameStreams?.RequestBody.Abort(error);
+                _frameStreams?.Abort(error);
-                _frameStreams?.ResponseBody.Abort();
 
                 LifetimeControl.End(ProduceEndType.SocketDisconnect);
 

src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/FrameDuplexStream.cs

@@ -10,7 +10,7 @@ using System.Threading.Tasks;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
 {
-    class FrameDuplexStream : Stream
+    internal class FrameDuplexStream : Stream
     {
         private readonly Stream _requestStream;
         private readonly Stream _responseStream;

src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/FrameRequestStream.cs

@@ -5,11 +5,12 @@ using System;
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
+using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
 using Microsoft.Extensions.Internal;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
 {
-    class FrameRequestStream : Stream
+    internal class FrameRequestStream : ReadOnlyStream
     {
         private MessageBody _body;
         private FrameStreamState _state;
@@ -20,30 +21,15 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             _state = FrameStreamState.Closed;
         }
 
-        public override bool CanRead => true;
-
         public override bool CanSeek => false;
 
-        public override bool CanWrite => false;
-
         public override long Length
-        {
+            => throw new NotSupportedException();
-            get
-            {
-                throw new NotSupportedException();
-            }
-        }
 
         public override long Position
         {
-            get
+            get => throw new NotSupportedException();
-            {
+            set => throw new NotSupportedException();
-                throw new NotSupportedException();
-            }
-            set
-            {
-                throw new NotSupportedException();
-            }
         }
 
         public override void Flush()
@@ -145,11 +131,6 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             return task;
         }
 
-        public override void Write(byte[] buffer, int offset, int count)
-        {
-            throw new NotSupportedException();
-        }
-
         public void StartAcceptingReads(MessageBody body)
         {
             // Only start if not aborted

src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/FrameResponseStream.cs

@@ -5,10 +5,11 @@ using System;
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
+using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
 {
-    class FrameResponseStream : Stream
+    internal class FrameResponseStream : WriteOnlyStream
     {
         private IFrameControl _frameControl;
         private FrameStreamState _state;
@@ -19,30 +20,15 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             _state = FrameStreamState.Closed;
         }
 
-        public override bool CanRead => false;
-
         public override bool CanSeek => false;
 
-        public override bool CanWrite => true;
-
         public override long Length
-        {
+            => throw new NotSupportedException();
-            get
-            {
-                throw new NotSupportedException();
-            }
-        }
 
         public override long Position
         {
-            get
+            get => throw new NotSupportedException();
-            {
+            set => throw new NotSupportedException();
-                throw new NotSupportedException();
-            }
-            set
-            {
-                throw new NotSupportedException();
-            }
         }
 
         public override void Flush()
@@ -72,11 +58,6 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             throw new NotSupportedException();
         }
 
-        public override int Read(byte[] buffer, int offset, int count)
-        {
-            throw new NotSupportedException();
-        }
-
         public override void Write(byte[] buffer, int offset, int count)
         {
             ValidateState(default(CancellationToken));

src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/MessageBody.cs

@@ -24,6 +24,8 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             _context = context;
         }
 
+        public static MessageBody ZeroContentLengthClose => _zeroContentLengthClose;
+
         public bool RequestKeepAlive { get; protected set; }
 
         public bool RequestUpgrade { get; protected set; }
@@ -237,15 +239,12 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             var keepAlive = httpVersion != HttpVersion.Http10;
 
             var connection = headers.HeaderConnection;
+            var upgrade = false;
             if (connection.Count > 0)
             {
                 var connectionOptions = FrameHeaders.ParseConnection(connection);
 
-                if ((connectionOptions & ConnectionOptions.Upgrade) == ConnectionOptions.Upgrade)
+                upgrade = (connectionOptions & ConnectionOptions.Upgrade) == ConnectionOptions.Upgrade;
-                {
-                    return new ForRemainingData(true, context);
-                }
-
                 keepAlive = (connectionOptions & ConnectionOptions.KeepAlive) == ConnectionOptions.KeepAlive;
             }
 
@@ -265,16 +264,26 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
                     context.RejectRequest(RequestRejectionReason.FinalTransferCodingNotChunked, transferEncoding.ToString());
                 }
 
+                if (upgrade)
+                {
+                    context.RejectRequest(RequestRejectionReason.UpgradeRequestCannotHavePayload);
+                }
+
                 return new ForChunkedEncoding(keepAlive, headers, context);
             }
 
             if (headers.ContentLength.HasValue)
             {
                 var contentLength = headers.ContentLength.Value;
+
                 if (contentLength == 0)
                 {
                     return keepAlive ? _zeroContentLengthKeepAlive : _zeroContentLengthClose;
                 }
+                else if (upgrade)
+                {
+                    context.RejectRequest(RequestRejectionReason.UpgradeRequestCannotHavePayload);
+                }
 
                 return new ForContentLength(keepAlive, contentLength, context);
             }
@@ -291,15 +300,20 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
                 }
             }
 
+            if (upgrade)
+            {
+                return new ForUpgrade(context);
+            }
+
             return keepAlive ? _zeroContentLengthKeepAlive : _zeroContentLengthClose;
         }
 
-        private class ForRemainingData : MessageBody
+        private class ForUpgrade : MessageBody
         {
-            public ForRemainingData(bool upgrade, Frame context)
+            public ForUpgrade(Frame context)
                 : base(context)
             {
-                RequestUpgrade = upgrade;
+                RequestUpgrade = true;
             }
 
             protected override ValueTask<ArraySegment<byte>> PeekAsync(CancellationToken cancellationToken)

src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/RequestRejectionReason.cs

@@ -30,5 +30,6 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
         MissingHostHeader,
         MultipleHostHeaders,
         InvalidHostHeader,
+        UpgradeRequestCannotHavePayload,
     }
 }

src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Infrastructure/ReadOnlyStream.cs

@@ -0,0 +1,29 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure
+{
+    public abstract class ReadOnlyStream : Stream
+    {
+        public override bool CanRead => true;
+
+        public override bool CanWrite => false;
+
+        public override int WriteTimeout
+        {
+            get => throw new NotSupportedException();
+            set => throw new NotSupportedException();
+        }
+
+        public override void Write(byte[] buffer, int offset, int count)
+            => throw new NotSupportedException();
+
+        public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+            => throw new NotSupportedException();
+    }
+}

src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Infrastructure/Streams.cs

@@ -1,21 +1,84 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
+using System.IO;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure
 {
-    class Streams
+    internal class Streams
     {
+        private static readonly ThrowingWriteOnlyStream _throwingResponseStream
+            = new ThrowingWriteOnlyStream(new InvalidOperationException(CoreStrings.ResponseStreamWasUpgraded));
+        private readonly FrameResponseStream _response;
+        private readonly FrameRequestStream _request;
+        private readonly WrappingStream _upgradeableResponse;
+        private readonly FrameRequestStream _emptyRequest;
+        private readonly Stream _upgradeStream;
+
         public Streams(IFrameControl frameControl)
         {
-            RequestBody = new FrameRequestStream();
+            _request = new FrameRequestStream();
-            ResponseBody = new FrameResponseStream(frameControl);
+            _emptyRequest = new FrameRequestStream();
-            DuplexStream = new FrameDuplexStream(RequestBody, ResponseBody);
+            _response = new FrameResponseStream(frameControl);
+            _upgradeableResponse = new WrappingStream(_response);
+            _upgradeStream = new FrameDuplexStream(_request, _response);
         }
 
-        public FrameRequestStream RequestBody { get; }
+        public Stream Upgrade()
-        public FrameResponseStream ResponseBody { get; }
+        {
-        public FrameDuplexStream DuplexStream { get; }
+            // causes writes to context.Response.Body to throw
+            _upgradeableResponse.SetInnerStream(_throwingResponseStream);
+            // _upgradeStream always uses _response
+            return _upgradeStream;
+        }
+
+        public (Stream request, Stream response) Start(MessageBody body)
+        {
+            _request.StartAcceptingReads(body);
+            _emptyRequest.StartAcceptingReads(MessageBody.ZeroContentLengthClose);
+            _response.StartAcceptingWrites();
+
+            if (body.RequestUpgrade)
+            {
+                // until Upgrade() is called, context.Response.Body should use the normal output stream
+                _upgradeableResponse.SetInnerStream(_response);
+                // upgradeable requests should never have a request body
+                return (_emptyRequest, _upgradeableResponse);
+            }
+            else
+            {
+                return (_request, _response);
+            }
+        }
+
+        public void Pause()
+        {
+            _request.PauseAcceptingReads();
+            _emptyRequest.PauseAcceptingReads();
+            _response.PauseAcceptingWrites();
+        }
+
+        public void Resume()
+        {
+            _request.ResumeAcceptingReads();
+            _emptyRequest.ResumeAcceptingReads();
+            _response.ResumeAcceptingWrites();
+        }
+
+        public void Stop()
+        {
+            _request.StopAcceptingReads();
+            _emptyRequest.StopAcceptingReads();
+            _response.StopAcceptingWrites();
+        }
+
+        public void Abort(Exception error)
+        {
+            _request.Abort(error);
+            _emptyRequest.Abort(error);
+            _response.Abort();
+        }
     }
 }

src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Infrastructure/ThrowingWriteOnlyStream.cs

@@ -0,0 +1,45 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure
+{
+    public class ThrowingWriteOnlyStream : WriteOnlyStream
+    {
+        private readonly Exception _exception;
+
+        public ThrowingWriteOnlyStream(Exception exception)
+        {
+            _exception = exception;
+        }
+
+        public override bool CanSeek => false;
+
+        public override long Length => throw new NotSupportedException();
+
+        public override long Position
+        {
+            get => throw new NotSupportedException();
+            set => throw new NotSupportedException();
+        }
+
+        public override void Write(byte[] buffer, int offset, int count)
+            => throw _exception;
+
+        public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+            => throw _exception;
+
+        public override void Flush()
+            => throw _exception;
+
+        public override long Seek(long offset, SeekOrigin origin)
+            => throw new NotSupportedException();
+
+        public override void SetLength(long value)
+            => throw new NotSupportedException();
+    }
+}

src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Infrastructure/WrappingStream.cs

@@ -0,0 +1,140 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.IO;
+#if NET46
+using System.Runtime.Remoting;
+#endif
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure
+{
+    internal class WrappingStream : Stream
+    {
+        private Stream _inner;
+        private bool _disposed;
+
+        public WrappingStream(Stream inner)
+        {
+            _inner = inner;
+        }
+
+        public void SetInnerStream(Stream inner)
+        {
+            if (_disposed)
+            {
+                throw new ObjectDisposedException(nameof(WrappingStream));
+            }
+
+            _inner = inner;
+        }
+
+        public override bool CanRead => _inner.CanRead;
+
+        public override bool CanSeek => _inner.CanSeek;
+
+        public override bool CanWrite => _inner.CanWrite;
+
+        public override bool CanTimeout => _inner.CanTimeout;
+
+        public override long Length => _inner.Length;
+
+        public override long Position
+        {
+            get => _inner.Position;
+            set => _inner.Position = value;
+        }
+
+        public override int ReadTimeout
+        {
+            get => _inner.ReadTimeout;
+            set => _inner.ReadTimeout = value;
+        }
+
+        public override int WriteTimeout
+        {
+            get => _inner.WriteTimeout;
+            set => _inner.WriteTimeout = value;
+        }
+
+        public override void Flush()
+            => _inner.Flush();
+
+        public override Task FlushAsync(CancellationToken cancellationToken)
+            => _inner.FlushAsync(cancellationToken);
+
+        public override int Read(byte[] buffer, int offset, int count)
+            => _inner.Read(buffer, offset, count);
+
+        public override Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+            => _inner.ReadAsync(buffer, offset, count, cancellationToken);
+
+        public override int ReadByte()
+            => _inner.ReadByte();
+
+        public override long Seek(long offset, SeekOrigin origin)
+            => _inner.Seek(offset, origin);
+
+        public override void SetLength(long value)
+            => _inner.SetLength(value);
+
+        public override void Write(byte[] buffer, int offset, int count)
+            => _inner.Write(buffer, offset, count);
+
+        public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+            => _inner.WriteAsync(buffer, offset, count, cancellationToken);
+
+        public override void WriteByte(byte value)
+            => _inner.WriteByte(value);
+
+        public override Task CopyToAsync(Stream destination, int bufferSize, CancellationToken cancellationToken)
+            => _inner.CopyToAsync(destination, bufferSize, cancellationToken);
+
+#if NET46
+        public override IAsyncResult BeginRead(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
+            => _inner.BeginRead(buffer, offset, count, callback, state);
+
+        public override IAsyncResult BeginWrite(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
+            => _inner.BeginWrite(buffer, offset, count, callback, state);
+
+        public override int EndRead(IAsyncResult asyncResult)
+            => _inner.EndRead(asyncResult);
+
+        public override void EndWrite(IAsyncResult asyncResult)
+            => _inner.EndWrite(asyncResult);
+
+        public override ObjRef CreateObjRef(Type requestedType)
+            => _inner.CreateObjRef(requestedType);
+
+        public override object InitializeLifetimeService()
+            => _inner.InitializeLifetimeService();
+
+        public override void Close()
+            => _inner.Close();
+
+#elif NETSTANDARD1_3
+#else
+#error Target framework should be updated
+#endif
+
+        public override bool Equals(object obj)
+            => _inner.Equals(obj);
+
+        public override int GetHashCode()
+            => _inner.GetHashCode();
+
+        public override string ToString()
+            => _inner.ToString();
+
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                _disposed = true;
+                _inner.Dispose();
+            }
+        }
+    }
+}

src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Infrastructure/WriteOnlyStream.cs

@@ -0,0 +1,29 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure
+{
+    public abstract class WriteOnlyStream : Stream
+    {
+        public override bool CanRead => false;
+
+        public override bool CanWrite => true;
+
+        public override int ReadTimeout
+        {
+            get => throw new NotSupportedException();
+            set => throw new NotSupportedException();
+        }
+
+        public override int Read(byte[] buffer, int offset, int count)
+            => throw new NotSupportedException();
+
+        public override Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+          => throw new NotSupportedException();
+    }
+}

src/Microsoft.AspNetCore.Server.Kestrel.Core/Microsoft.AspNetCore.Server.Kestrel.Core.csproj

@@ -20,6 +20,7 @@
     <PackageReference Include="Microsoft.Extensions.Options" Version="$(AspNetCoreVersion)" />
     <PackageReference Include="Microsoft.Extensions.TaskCache.Sources" Version="$(AspNetCoreVersion)" PrivateAssets="All" />
 
+    <PackageReference Include="System.ValueTuple" Version="$(CoreFxVersion)" />
     <PackageReference Include="System.Threading.Tasks.Extensions" Version="$(CoreFxVersion)" />
   </ItemGroup>
 
@@ -33,4 +34,10 @@
     <PackageReference Include="System.Threading.ThreadPool" Version="$(CoreFxVersion)" />
   </ItemGroup>
 
+  <ItemGroup>
+    <EmbeddedResource Update="CoreStrings.resx">
+      <Generator></Generator>
+    </EmbeddedResource>
+  </ItemGroup>
+
 </Project>

src/Microsoft.AspNetCore.Server.Kestrel.Core/Properties/CoreStrings.Designer.cs

@@ -0,0 +1,44 @@
+// <auto-generated />
+namespace Microsoft.AspNetCore.Server.Kestrel.Core
+{
+    using System.Globalization;
+    using System.Reflection;
+    using System.Resources;
+
+    internal static class CoreStrings
+    {
+        private static readonly ResourceManager _resourceManager
+            = new ResourceManager("Microsoft.AspNetCore.Server.Kestrel.Core.CoreStrings", typeof(CoreStrings).GetTypeInfo().Assembly);
+
+        /// <summary>
+        /// Cannot write to response body after connection has been upgraded.
+        /// </summary>
+        internal static string ResponseStreamWasUpgraded
+        {
+            get => GetString("ResponseStreamWasUpgraded");
+        }
+
+        /// <summary>
+        /// Cannot write to response body after connection has been upgraded.
+        /// </summary>
+        internal static string FormatResponseStreamWasUpgraded()
+            => GetString("ResponseStreamWasUpgraded");
+
+        private static string GetString(string name, params string[] formatterNames)
+        {
+            var value = _resourceManager.GetString(name);
+
+            System.Diagnostics.Debug.Assert(value != null);
+
+            if (formatterNames != null)
+            {
+                for (var i = 0; i < formatterNames.Length; i++)
+                {
+                    value = value.Replace("{" + formatterNames[i] + "}", "{" + i + "}");
+                }
+            }
+
+            return value;
+        }
+    }
+}

test/Microsoft.AspNetCore.Server.Kestrel.Core.Tests/FrameRequestStreamTests.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.IO;
+using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
 using Moq;

test/Microsoft.AspNetCore.Server.Kestrel.Core.Tests/FrameTests.cs

@@ -256,10 +256,8 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
 
             var originalRequestBody = _frame.RequestBody;
             var originalResponseBody = _frame.ResponseBody;
-            var originalDuplexStream = _frame.DuplexStream;
             _frame.RequestBody = new MemoryStream();
             _frame.ResponseBody = new MemoryStream();
-            _frame.DuplexStream = new MemoryStream();
 
             // Act
             _frame.InitializeStreams(messageBody);
@@ -267,7 +265,6 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             // Assert
             Assert.Same(originalRequestBody, _frame.RequestBody);
             Assert.Same(originalResponseBody, _frame.ResponseBody);
-            Assert.Same(originalDuplexStream, _frame.DuplexStream);
         }
 
         [Theory]

test/Microsoft.AspNetCore.Server.Kestrel.Core.Tests/StreamsTests.cs

@@ -0,0 +1,89 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
+using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
+using Moq;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
+{
+    public class StreamsTests
+    {
+        [Fact]
+        public async Task StreamsThrowAfterAbort()
+        {
+            var streams = new Streams(Mock.Of<IFrameControl>());
+            var (request, response) = streams.Start(new MockMessageBody());
+
+            var ex = new Exception("My error");
+            streams.Abort(ex);
+
+            await response.WriteAsync(new byte[1], 0, 1);
+            Assert.Same(ex,
+                await Assert.ThrowsAsync<Exception>(() => request.ReadAsync(new byte[1], 0, 1)));
+        }
+
+        [Fact]
+        public async Task StreamsThrowOnAbortAfterUpgrade()
+        {
+            var streams = new Streams(Mock.Of<IFrameControl>());
+            var (request, response) = streams.Start(new MockMessageBody(upgradeable: true));
+
+            var upgrade = streams.Upgrade();
+            var ex = new Exception("My error");
+            streams.Abort(ex);
+
+            var writeEx = await Assert.ThrowsAsync<InvalidOperationException>(() => response.WriteAsync(new byte[1], 0, 1));
+            Assert.Equal(CoreStrings.ResponseStreamWasUpgraded, writeEx.Message);
+
+            Assert.Same(ex,
+              await Assert.ThrowsAsync<Exception>(() => request.ReadAsync(new byte[1], 0, 1)));
+
+            Assert.Same(ex,
+                await Assert.ThrowsAsync<Exception>(() => upgrade.ReadAsync(new byte[1], 0, 1)));
+
+            await upgrade.WriteAsync(new byte[1], 0, 1);
+        }
+
+        [Fact]
+        public async Task StreamsThrowOnUpgradeAfterAbort()
+        {
+            var streams = new Streams(Mock.Of<IFrameControl>());
+
+            var (request, response) = streams.Start(new MockMessageBody(upgradeable: true));
+            var ex = new Exception("My error");
+            streams.Abort(ex);
+
+            var upgrade = streams.Upgrade();
+
+            var writeEx = await Assert.ThrowsAsync<InvalidOperationException>(() => response.WriteAsync(new byte[1], 0, 1));
+            Assert.Equal(CoreStrings.ResponseStreamWasUpgraded, writeEx.Message);
+
+            Assert.Same(ex,
+              await Assert.ThrowsAsync<Exception>(() => request.ReadAsync(new byte[1], 0, 1)));
+
+            Assert.Same(ex,
+                await Assert.ThrowsAsync<Exception>(() => upgrade.ReadAsync(new byte[1], 0, 1)));
+
+            await upgrade.WriteAsync(new byte[1], 0, 1);
+        }
+
+        private class MockMessageBody : MessageBody
+        {
+            public MockMessageBody(bool upgradeable = false)
+                : base(null)
+            {
+                RequestUpgrade = upgradeable;
+            }
+
+            protected override ValueTask<ArraySegment<byte>> PeekAsync(CancellationToken cancellationToken)
+            {
+                return new ValueTask<ArraySegment<byte>>(new ArraySegment<byte>(new byte[1]));
+            }
+        }
+    }
+}

test/Microsoft.AspNetCore.Server.Kestrel.Core.Tests/ThrowingWriteOnlyStreamTests.cs

@@ -0,0 +1,29 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
+{
+    public class ThrowingWriteOnlyStreamTests
+    {
+        [Fact]
+        public async Task ThrowsOnWrite()
+        {
+            var ex = new Exception("my error");
+            var stream = new ThrowingWriteOnlyStream(ex);
+
+            Assert.True(stream.CanWrite);
+            Assert.False(stream.CanRead);
+            Assert.False(stream.CanSeek);
+            Assert.False(stream.CanTimeout);
+            Assert.Same(ex, Assert.Throws<Exception>(() => stream.Write(new byte[1], 0, 1)));
+            Assert.Same(ex, await Assert.ThrowsAsync<Exception>(() => stream.WriteAsync(new byte[1], 0, 1)));
+            Assert.Same(ex, Assert.Throws<Exception>(() => stream.Flush()));
+            Assert.Same(ex, await Assert.ThrowsAsync<Exception>(() => stream.FlushAsync()));
+        }
+    }
+}

test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/UpgradeTests.cs

@@ -0,0 +1,174 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.IO;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Http.Features;
+using Microsoft.AspNetCore.Server.Kestrel.Core;
+using Microsoft.AspNetCore.Testing;
+using Microsoft.Extensions.Internal;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
+{
+    public class UpgradeTests
+    {
+        [Fact]
+        public async Task ResponseThrowsAfterUpgrade()
+        {
+            var upgrade = new TaskCompletionSource<bool>();
+            using (var server = new TestServer(async context =>
+            {
+                var feature = context.Features.Get<IHttpUpgradeFeature>();
+                var stream = await feature.UpgradeAsync();
+
+                var ex = Assert.Throws<InvalidOperationException>(() => context.Response.Body.WriteByte((byte)' '));
+                Assert.Equal(CoreStrings.ResponseStreamWasUpgraded, ex.Message);
+
+                using (var writer = new StreamWriter(stream))
+                {
+                    writer.WriteLine("New protocol data");
+                }
+
+                upgrade.TrySetResult(true);
+            }))
+            {
+                using (var connection = server.CreateConnection())
+                {
+                    await connection.Send("GET / HTTP/1.1",
+                        "Host:",
+                        "Connection: Upgrade",
+                        "",
+                        "");
+                    await connection.Receive("HTTP/1.1 101 Switching Protocols",
+                        "Connection: Upgrade",
+                        $"Date: {server.Context.DateHeaderValue}",
+                        "",
+                        "");
+
+                    await connection.Receive("New protocol data");
+                    await upgrade.Task.TimeoutAfter(TimeSpan.FromSeconds(30));
+                }
+            }
+        }
+
+        [Fact]
+        public async Task RequestBodyAlwaysEmptyAfterUpgrade()
+        {
+            const string send = "Custom protocol send";
+            const string recv = "Custom protocol recv";
+
+            var upgrade = new TaskCompletionSource<bool>();
+            using (var server = new TestServer(async context =>
+            {
+                try
+                {
+                    var feature = context.Features.Get<IHttpUpgradeFeature>();
+                    var stream = await feature.UpgradeAsync();
+
+                    var buffer = new byte[128];
+                    var read = await context.Request.Body.ReadAsync(buffer, 0, 128).TimeoutAfter(TimeSpan.FromSeconds(10));
+                    Assert.Equal(0, read);
+
+                    using (var reader = new StreamReader(stream))
+                    using (var writer = new StreamWriter(stream))
+                    {
+                        var line = await reader.ReadLineAsync();
+                        Assert.Equal(send, line);
+                        await writer.WriteLineAsync(recv);
+                    }
+
+                    upgrade.TrySetResult(true);
+                }
+                catch (Exception ex)
+                {
+                    upgrade.SetException(ex);
+                    throw;
+                }
+            }))
+            {
+                using (var connection = server.CreateConnection())
+                {
+                    await connection.Send("GET / HTTP/1.1",
+                        "Host:",
+                        "Connection: Upgrade",
+                        "",
+                        "");
+
+                    await connection.Receive("HTTP/1.1 101 Switching Protocols",
+                        "Connection: Upgrade",
+                        $"Date: {server.Context.DateHeaderValue}",
+                        "",
+                        "");
+
+                    await connection.Send(send + "\r\n");
+                    await connection.Receive(recv);
+
+                    await upgrade.Task.TimeoutAfter(TimeSpan.FromSeconds(30));
+                }
+            }
+        }
+
+        [Fact]
+        public async Task RejectsRequestWithContentLengthAndUpgrade()
+        {
+            using (var server = new TestServer(context => TaskCache.CompletedTask))
+            using (var connection = server.CreateConnection())
+            {
+                await connection.Send("POST / HTTP/1.1",
+                    "Host:",
+                    "Content-Length: 1",
+                    "Connection: Upgrade",
+                    "",
+                    "1");
+
+                await connection.Receive("HTTP/1.1 400 Bad Request");
+            }
+        }
+
+        [Fact]
+        public async Task AcceptsRequestWithNoContentLengthAndUpgrade()
+        {
+            using (var server = new TestServer(context => TaskCache.CompletedTask))
+            {
+                using (var connection = server.CreateConnection())
+                {
+                    await connection.Send("POST / HTTP/1.1",
+                        "Host:",
+                        "Content-Length: 0",
+                        "Connection: Upgrade, keep-alive",
+                        "",
+                        "");
+                    await connection.Receive("HTTP/1.1 200 OK");
+                }
+
+                using (var connection = server.CreateConnection())
+                {
+                    await connection.Send("GET / HTTP/1.1",
+                        "Host:",
+                        "Connection: Upgrade",
+                        "",
+                        "");
+                    await connection.Receive("HTTP/1.1 200 OK");
+                }
+            }
+        }
+
+        [Fact]
+        public async Task RejectsRequestWithChunkedEncodingAndUpgrade()
+        {
+            using (var server = new TestServer(context => TaskCache.CompletedTask))
+            using (var connection = server.CreateConnection())
+            {
+                await connection.Send("POST / HTTP/1.1",
+                    "Host:",
+                    "Transfer-Encoding: chunked",
+                    "Connection: Upgrade",
+                    "",
+                    "");
+                await connection.Receive("HTTP/1.1 400 Bad Request");
+            }
+        }
+    }
+}