From 231e6a5b7d92a7455b5c64f8e4a71a6fcc73cfd1 Mon Sep 17 00:00:00 2001
From: Andrew McCall <andrew@andrewmccall.com>
Date: Fri, 23 Dec 2016 21:10:26 +0000
Subject: [PATCH] Calls to discardSomeReadBytes() causes the JsonDecoder to get
 corrupted

Modification:

Added a lastReaderIndex value and if the current readerIndex has been reset, resets the idx and the decoder.

Result:

Fixes #6156.
---
 .../handler/codec/json/JsonObjectDecoder.java |  8 +++++
 .../codec/json/JsonObjectDecoderTest.java     | 32 +++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/codec/src/main/java/io/netty/handler/codec/json/JsonObjectDecoder.java b/codec/src/main/java/io/netty/handler/codec/json/JsonObjectDecoder.java
index 7af1d74646..cd5db99ff7 100644
--- a/codec/src/main/java/io/netty/handler/codec/json/JsonObjectDecoder.java
+++ b/codec/src/main/java/io/netty/handler/codec/json/JsonObjectDecoder.java
@@ -45,6 +45,8 @@ public class JsonObjectDecoder extends ByteToMessageDecoder {
     private int openBraces;
     private int idx;
 
+    private int lastReaderIndex;
+
     private int state;
     private boolean insideString;
 
@@ -88,6 +90,11 @@ public class JsonObjectDecoder extends ByteToMessageDecoder {
             return;
         }
 
+        if (this.idx > in.readerIndex() && lastReaderIndex != in.readerIndex()) {
+            this.idx = in.readerIndex();
+            reset();
+        }
+
         // index of next byte to process.
         int idx = this.idx;
         int wrtIdx = in.writerIndex();
@@ -170,6 +177,7 @@ public class JsonObjectDecoder extends ByteToMessageDecoder {
         } else {
             this.idx = idx;
         }
+        this.lastReaderIndex = in.readerIndex();
     }
 
     /**
diff --git a/codec/src/test/java/io/netty/handler/codec/json/JsonObjectDecoderTest.java b/codec/src/test/java/io/netty/handler/codec/json/JsonObjectDecoderTest.java
index 083b4eb1d4..e1f28a5794 100644
--- a/codec/src/test/java/io/netty/handler/codec/json/JsonObjectDecoderTest.java
+++ b/codec/src/test/java/io/netty/handler/codec/json/JsonObjectDecoderTest.java
@@ -276,4 +276,36 @@ public class JsonObjectDecoderTest {
 
         assertFalse(ch.finish());
     }
+
+    @Test
+    public void testCorruptedFrameException() {
+        final String part1 = "{\"a\":{\"b\":{\"c\":{ \"d\":\"27301\", \"med\":\"d\", \"path\":\"27310\"} }," +
+                " \"status\":\"OK\" } }{\"";
+        final String part2 = "a\":{\"b\":{\"c\":{\"ory\":[{\"competi\":[{\"event\":[{" + "\"externalI\":{\"external\"" +
+                ":[{\"id\":\"O\"} ]";
+
+        EmbeddedChannel ch = new EmbeddedChannel(new JsonObjectDecoder());
+
+        ByteBuf res;
+
+        ch.writeInbound(Unpooled.copiedBuffer(part1, CharsetUtil.UTF_8));
+        res = ch.readInbound();
+        assertEquals("{\"a\":{\"b\":{\"c\":{ \"d\":\"27301\", \"med\":\"d\", \"path\":\"27310\"} }, " +
+                "\"status\":\"OK\" } }", res.toString(CharsetUtil.UTF_8));
+        res.release();
+
+        ch.writeInbound(Unpooled.copiedBuffer(part2, CharsetUtil.UTF_8));
+        res = ch.readInbound();
+
+        assertNull(res);
+
+        ch.writeInbound(Unpooled.copiedBuffer("}}]}]}]}}}}", CharsetUtil.UTF_8));
+        res = ch.readInbound();
+
+        assertEquals("{\"a\":{\"b\":{\"c\":{\"ory\":[{\"competi\":[{\"event\":[{" + "\"externalI\":{" +
+                "\"external\":[{\"id\":\"O\"} ]}}]}]}]}}}}", res.toString(CharsetUtil.UTF_8));
+        res.release();
+
+        assertFalse(ch.finish());
+    }
 }