Handle response content length mismatches (#175).

Author: Cesar Blum Silveira

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

@@ -4,6 +4,7 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Globalization;
 using System.IO;
 using System.Linq;
 using System.Net;
@@ -75,7 +76,7 @@ public abstract partial class Frame : IFrameControl
         protected readonly long _keepAliveMilliseconds;
         private readonly long _requestHeadersTimeoutMilliseconds;
 
-        private int _responseBytesWritten;
+        protected long _responseBytesWritten;
 
         public Frame(ConnectionContext context)
         {
@@ -516,8 +517,8 @@ public async Task FlushAsync(CancellationToken cancellationToken)
 
         public void Write(ArraySegment<byte> data)
         {
+            VerifyAndUpdateWrite(data.Count);
             ProduceStartAndFireOnStarting().GetAwaiter().GetResult();
-            _responseBytesWritten += data.Count;
 
             if (_canHaveBody)
             {
@@ -547,7 +548,7 @@ public Task WriteAsync(ArraySegment<byte> data, CancellationToken cancellationTo
                 return WriteAsyncAwaited(data, cancellationToken);
             }
 
-            _responseBytesWritten += data.Count;
+            VerifyAndUpdateWrite(data.Count);
 
             if (_canHaveBody)
             {
@@ -573,8 +574,9 @@ public Task WriteAsync(ArraySegment<byte> data, CancellationToken cancellationTo
 
         public async Task WriteAsyncAwaited(ArraySegment<byte> data, CancellationToken cancellationToken)
         {
+            VerifyAndUpdateWrite(data.Count);
+
             await ProduceStartAndFireOnStarting();
-            _responseBytesWritten += data.Count;
 
             if (_canHaveBody)
             {
@@ -598,6 +600,23 @@ public async Task WriteAsyncAwaited(ArraySegment<byte> data, CancellationToken c
             }
         }
 
+        private void VerifyAndUpdateWrite(int count)
+        {
+            var responseHeaders = FrameResponseHeaders;
+
+            if (responseHeaders != null &&
+                !responseHeaders.HasTransferEncoding &&
+                responseHeaders.HasContentLength &&
+                _responseBytesWritten + count > responseHeaders.HeaderContentLengthValue.Value)
+            {
+                _keepAlive = false;
+                throw new InvalidOperationException(
+                    $"Response Content-Length mismatch: too many bytes written ({_responseBytesWritten + count} of {responseHeaders.HeaderContentLengthValue.Value}).");
+            }
+
+            _responseBytesWritten += count;
+        }
+
         private void WriteChunked(ArraySegment<byte> data)
         {
             SocketOutput.Write(data, chunk: true);

src/Microsoft.AspNetCore.Server.Kestrel/Internal/Http/FrameHeaders.Generated.cs

@@ -3697,6 +3697,7 @@ protected override void ClearFast()
         {
             _bits = 0;
             _headers = default(HeaderReferences);
+            
             MaybeUnknown?.Clear();
         }
 
@@ -5670,6 +5671,7 @@ public StringValues HeaderContentLength
             }
             set
             {
+                _contentLength = ParseContentLength(value);
                 _bits |= 2048L;
                 _headers._ContentLength = value; 
                 _headers._rawContentLength = null;
@@ -7384,6 +7386,7 @@ protected override void SetValueFast(string key, StringValues value)
                     {
                         if ("Content-Length".Equals(key, StringComparison.OrdinalIgnoreCase))
                         {
+                            _contentLength = ParseContentLength(value);
                             _bits |= 2048L;
                             _headers._ContentLength = value;
                             _headers._rawContentLength = null;
@@ -7809,6 +7812,7 @@ protected override void AddValueFast(string key, StringValues value)
                             {
                                 ThrowDuplicateKeyException();
                             }
+                            _contentLength = ParseContentLength(value);
                             _bits |= 2048L;
                             _headers._ContentLength = value;
                             _headers._rawContentLength = null;
@@ -8350,6 +8354,7 @@ protected override bool RemoveFast(string key)
                         {
                             if (((_bits & 2048L) != 0))
                             {
+                                _contentLength = null;
                                 _bits &= ~2048L;
                                 _headers._ContentLength = StringValues.Empty;
                                 _headers._rawContentLength = null;
@@ -8601,6 +8606,7 @@ protected override void ClearFast()
         {
             _bits = 0;
             _headers = default(HeaderReferences);
+            _contentLength = null;
             MaybeUnknown?.Clear();
         }
 

src/Microsoft.AspNetCore.Server.Kestrel/Internal/Http/FrameHeaders.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Globalization;
 using System.Linq;
 using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.Primitives;
@@ -232,6 +233,18 @@ public static void ValidateHeaderCharacters(string headerCharacters)
             }
         }
 
+        public static long ParseContentLength(StringValues value)
+        {
+            try
+            {
+                return long.Parse(value, NumberStyles.AllowLeadingWhite | NumberStyles.AllowTrailingWhite, CultureInfo.InvariantCulture);
+            }
+            catch (FormatException ex)
+            {
+                throw new InvalidOperationException("Content-Length value must be an integral number.", ex);
+            }
+        }
+
         private static void ThrowInvalidHeaderCharacter(char ch)
         {
             throw new InvalidOperationException(string.Format("Invalid non-ASCII or control character in header: 0x{0:X4}", (ushort)ch));

src/Microsoft.AspNetCore.Server.Kestrel/Internal/Http/FrameOfT.cs

@@ -92,6 +92,16 @@ public override async Task RequestProcessingAsync()
                         try
                         {
                             await _application.ProcessRequestAsync(context).ConfigureAwait(false);
+
+                            var responseHeaders = FrameResponseHeaders;
+                            if (!responseHeaders.HasTransferEncoding &&
+                                responseHeaders.HasContentLength &&
+                                _responseBytesWritten < responseHeaders.HeaderContentLengthValue.Value)
+                            {
+                                _keepAlive = false;
+                                ReportApplicationError(new InvalidOperationException(
+                                    $"Response Content-Length mismatch: too few bytes written ({_responseBytesWritten} of {responseHeaders.HeaderContentLengthValue.Value})."));
+                            }
                         }
                         catch (Exception ex)
                         {

src/Microsoft.AspNetCore.Server.Kestrel/Internal/Http/FrameResponseHeaders.cs

@@ -13,6 +13,8 @@ public partial class FrameResponseHeaders : FrameHeaders
         private static readonly byte[] _CrLf = new[] { (byte)'\r', (byte)'\n' };
         private static readonly byte[] _colonSpace = new[] { (byte)':', (byte)' ' };
 
+        private long? _contentLength;
+
         public bool HasConnection => HeaderConnection.Count != 0;
 
         public bool HasTransferEncoding => HeaderTransferEncoding.Count != 0;
@@ -23,6 +25,8 @@ public partial class FrameResponseHeaders : FrameHeaders
 
         public bool HasDate => HeaderDate.Count != 0;
 
+        public long? HeaderContentLengthValue => _contentLength;
+
         public Enumerator GetEnumerator()
         {
             return new Enumerator(this);

src/Microsoft.AspNetCore.Server.Kestrel/Internal/Infrastructure/IKestrelTrace.cs

@@ -33,7 +33,7 @@ public interface IKestrelTrace : ILogger
 
         void ConnectionDisconnectedWrite(string connectionId, int count, Exception ex);
 
-        void ConnectionHeadResponseBodyWrite(string connectionId, int count);
+        void ConnectionHeadResponseBodyWrite(string connectionId, long count);
 
         void ConnectionBadRequest(string connectionId, BadHttpRequestException ex);
 

src/Microsoft.AspNetCore.Server.Kestrel/Internal/Infrastructure/KestrelTrace.cs

@@ -24,7 +24,7 @@ public class KestrelTrace : IKestrelTrace
         private static readonly Action<ILogger, string, Exception> _applicationError;
         private static readonly Action<ILogger, string, Exception> _connectionError;
         private static readonly Action<ILogger, string, int, Exception> _connectionDisconnectedWrite;
-        private static readonly Action<ILogger, string, int, Exception> _connectionHeadResponseBodyWrite;
+        private static readonly Action<ILogger, string, long, Exception> _connectionHeadResponseBodyWrite;
         private static readonly Action<ILogger, Exception> _notAllConnectionsClosedGracefully;
         private static readonly Action<ILogger, string, string, Exception> _connectionBadRequest;
 
@@ -49,7 +49,7 @@ static KestrelTrace()
             _connectionDisconnectedWrite = LoggerMessage.Define<string, int>(LogLevel.Debug, 15, @"Connection id ""{ConnectionId}"" write of ""{count}"" bytes to disconnected client.");
             _notAllConnectionsClosedGracefully = LoggerMessage.Define(LogLevel.Debug, 16, "Some connections failed to close gracefully during server shutdown.");
             _connectionBadRequest = LoggerMessage.Define<string, string>(LogLevel.Information, 17, @"Connection id ""{ConnectionId}"" bad request data: ""{message}""");
-            _connectionHeadResponseBodyWrite = LoggerMessage.Define<string, int>(LogLevel.Debug, 18, @"Connection id ""{ConnectionId}"" write of ""{count}"" body bytes to non-body HEAD response.");
+            _connectionHeadResponseBodyWrite = LoggerMessage.Define<string, long>(LogLevel.Debug, 18, @"Connection id ""{ConnectionId}"" write of ""{count}"" body bytes to non-body HEAD response.");
         }
 
         public KestrelTrace(ILogger logger)
@@ -135,7 +135,7 @@ public virtual void ConnectionDisconnectedWrite(string connectionId, int count,
             _connectionDisconnectedWrite(_logger, connectionId, count, ex);
         }
 
-        public virtual void ConnectionHeadResponseBodyWrite(string connectionId, int count)
+        public virtual void ConnectionHeadResponseBodyWrite(string connectionId, long count)
         {
             _connectionHeadResponseBodyWrite(_logger, connectionId, count, null);
         }