From 307e020703a8bf697bf4b8ed463c53dedd8391b1 Mon Sep 17 00:00:00 2001
From: Cesar Blum Silveira <cesars@microsoft.com>
Date: Wed, 18 Nov 2015 16:32:22 -0800
Subject: [PATCH] Don't crash the server if a connection filter throws
 synchronously.

---
 .../Http/Connection.cs                        | 42 +++++++++++--------
 .../ConnectionFilterTests.cs                  | 40 +++++++++++++++++-
 2 files changed, 64 insertions(+), 18 deletions(-)

diff --git a/src/Microsoft.AspNet.Server.Kestrel/Http/Connection.cs b/src/Microsoft.AspNet.Server.Kestrel/Http/Connection.cs
index c2ff59be01..4af0676761 100644
--- a/src/Microsoft.AspNet.Server.Kestrel/Http/Connection.cs
+++ b/src/Microsoft.AspNet.Server.Kestrel/Http/Connection.cs
@@ -78,25 +78,33 @@ namespace Microsoft.AspNet.Server.Kestrel.Http
                     Address = ServerAddress
                 };
 
-                ConnectionFilter.OnConnection(_filterContext).ContinueWith((task, state) =>
+                try
                 {
-                    var connection = (Connection)state;
+                    ConnectionFilter.OnConnection(_filterContext).ContinueWith((task, state) =>
+                    {
+                        var connection = (Connection)state;
 
-                    if (task.IsFaulted)
-                    {
-                        connection.Log.LogError("ConnectionFilter.OnConnection", task.Exception);
-                        connection.ConnectionControl.End(ProduceEndType.SocketDisconnect);
-                    }
-                    else if (task.IsCanceled)
-                    {
-                        connection.Log.LogError("ConnectionFilter.OnConnection Canceled");
-                        connection.ConnectionControl.End(ProduceEndType.SocketDisconnect);
-                    }
-                    else
-                    {
-                        connection.ApplyConnectionFilter();
-                    }
-                }, this);
+                        if (task.IsFaulted)
+                        {
+                            connection.Log.LogError("ConnectionFilter.OnConnection", task.Exception);
+                            connection.ConnectionControl.End(ProduceEndType.SocketDisconnect);
+                        }
+                        else if (task.IsCanceled)
+                        {
+                            connection.Log.LogError("ConnectionFilter.OnConnection Canceled");
+                            connection.ConnectionControl.End(ProduceEndType.SocketDisconnect);
+                        }
+                        else
+                        {
+                            connection.ApplyConnectionFilter();
+                        }
+                    }, this);
+                }
+                catch (Exception ex)
+                {
+                    Log.LogError("ConnectionFilter.OnConnection", ex);
+                    ConnectionControl.End(ProduceEndType.SocketDisconnect);
+                }
             }
         }
 
diff --git a/test/Microsoft.AspNet.Server.KestrelTests/ConnectionFilterTests.cs b/test/Microsoft.AspNet.Server.KestrelTests/ConnectionFilterTests.cs
index 5842e1d7c0..5dbe530f14 100644
--- a/test/Microsoft.AspNet.Server.KestrelTests/ConnectionFilterTests.cs
+++ b/test/Microsoft.AspNet.Server.KestrelTests/ConnectionFilterTests.cs
@@ -1,6 +1,7 @@
 // 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.AspNet.Http;
@@ -80,7 +81,36 @@ namespace Microsoft.AspNet.Server.KestrelTests
                         "Hello World!");
                 }
             }
-       }
+        }
+
+        [ConditionalFact]
+        [FrameworkSkipCondition(RuntimeFrameworks.Mono, SkipReason = "Test hangs after execution on Mono.")]
+        public async Task ThrowingSynchronousConnectionFilterDoesNotCrashServer()
+        {
+            var serviceContext = new TestServiceContext()
+            {
+                ConnectionFilter = new ThrowingConnectionFilter()
+            };
+
+            using (var server = new TestServer(App, serviceContext))
+            {
+                using (var connection = new TestConnection())
+                {
+                    try
+                    {
+                        await connection.SendEnd(
+                            "POST / HTTP/1.0",
+                            "",
+                            "Hello World?");
+                    }
+                    catch (IOException)
+                    {
+                        // Will throw because the exception in the connection filter will close the connection.
+                        Assert.True(true);
+                    }
+                }
+            }
+        }
 
         private class RewritingConnectionFilter : IConnectionFilter
         {
@@ -112,6 +142,14 @@ namespace Microsoft.AspNet.Server.KestrelTests
             }
         }
 
+        private class ThrowingConnectionFilter : IConnectionFilter
+        {
+            public Task OnConnection(ConnectionFilterContext context)
+            {
+                throw new Exception();
+            }
+        }
+
         private class RewritingStream : Stream
         {
             private readonly Stream _innerStream;