From 12911a0efe93788b4185d43b13fb73b0209551ca Mon Sep 17 00:00:00 2001
From: Norman Maurer <norman_maurer@apple.com>
Date: Tue, 7 Jun 2016 10:27:53 +0200
Subject: [PATCH] Ensure valid message sequence if channel is closed before
 receive headers.

Motivation:

When the channel is closed while we still decode the headers we currently not preserve correct message sequence. In this case we should generate an invalid message with a current cause.

Modifications:

Create an invalid message with a PrematureChannelClosureException as cause when the channel is closed while we decode the headers.

Result:

Correct message sequence preserved and correct DecoderResult if the channel is closed while decode headers.
---
 .../handler/codec/http/HttpObjectDecoder.java     | 15 +++++++++++++--
 .../codec/http/HttpResponseDecoderTest.java       | 14 ++++++++++++++
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectDecoder.java b/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectDecoder.java
index bb39f9c1b4..5a2de5bc8a 100644
--- a/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectDecoder.java
+++ b/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectDecoder.java
@@ -22,6 +22,7 @@ import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelPipeline;
 import io.netty.handler.codec.ByteToMessageDecoder;
 import io.netty.handler.codec.DecoderResult;
+import io.netty.handler.codec.PrematureChannelClosureException;
 import io.netty.handler.codec.TooLongFrameException;
 import io.netty.util.internal.AppendableCharSequence;
 
@@ -413,9 +414,19 @@ public abstract class HttpObjectDecoder extends ByteToMessageDecoder {
             if (currentState == State.READ_VARIABLE_LENGTH_CONTENT && !in.isReadable() && !chunked) {
                 // End of connection.
                 out.add(LastHttpContent.EMPTY_LAST_CONTENT);
-                reset();
+                resetNow();
                 return;
             }
+
+            if (currentState == State.READ_HEADER) {
+                // If we are still in the state of reading headers we need to create a new invalid message that
+                // signals that the connection was closed before we received the headers.
+                out.add(invalidMessage(Unpooled.EMPTY_BUFFER,
+                        new PrematureChannelClosureException("Connection closed before received headers")));
+                resetNow();
+                return;
+            }
+
             // Check if the closure of the connection signifies the end of the content.
             boolean prematureClosure;
             if (isDecodingRequest() || chunked) {
@@ -427,11 +438,11 @@ public abstract class HttpObjectDecoder extends ByteToMessageDecoder {
                 // connection, so it is perfectly fine.
                 prematureClosure = contentLength() > 0;
             }
-            resetNow();
 
             if (!prematureClosure) {
                 out.add(LastHttpContent.EMPTY_LAST_CONTENT);
             }
+            resetNow();
         }
     }
 
diff --git a/codec-http/src/test/java/io/netty/handler/codec/http/HttpResponseDecoderTest.java b/codec-http/src/test/java/io/netty/handler/codec/http/HttpResponseDecoderTest.java
index 5706b06a34..5db91d6bc8 100644
--- a/codec-http/src/test/java/io/netty/handler/codec/http/HttpResponseDecoderTest.java
+++ b/codec-http/src/test/java/io/netty/handler/codec/http/HttpResponseDecoderTest.java
@@ -18,6 +18,7 @@ package io.netty.handler.codec.http;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
 import io.netty.channel.embedded.EmbeddedChannel;
+import io.netty.handler.codec.PrematureChannelClosureException;
 import io.netty.handler.codec.TooLongFrameException;
 import io.netty.handler.codec.http.HttpHeaders.Names;
 import io.netty.util.CharsetUtil;
@@ -611,4 +612,17 @@ public class HttpResponseDecoderTest {
         // .. even after the connection is closed.
         assertThat(channel.finish(), is(false));
     }
+
+    @Test
+    public void testConnectionClosedBeforeHeadersReceived() {
+        EmbeddedChannel channel = new EmbeddedChannel(new HttpResponseDecoder());
+        String responseInitialLine =
+                "HTTP/1.1 200 OK\r\n";
+        assertFalse(channel.writeInbound(Unpooled.copiedBuffer(responseInitialLine, CharsetUtil.US_ASCII)));
+        assertTrue(channel.finish());
+        HttpMessage message = (HttpMessage) channel.readInbound();
+        assertTrue(message.getDecoderResult().isFailure());
+        assertThat(message.getDecoderResult().cause(), instanceOf(PrematureChannelClosureException.class));
+        assertNull(channel.readInbound());
+    }
 }