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1   /*
2    * Copyright 2014 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License,
5    * version 2.0 (the "License"); you may not use this file except in compliance
6    * with the License. You may obtain a copy of the License at:
7    *
8    *   http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13   * License for the specific language governing permissions and limitations
14   * under the License.
15   */
16  package io.netty.handler.codec.http.websocketx;
17  
18  import io.netty.buffer.ByteBuf;
19  import io.netty.buffer.Unpooled;
20  import io.netty.channel.ChannelFutureListener;
21  import io.netty.channel.ChannelHandlerAdapter;
22  import io.netty.channel.ChannelHandlerContext;
23  import io.netty.handler.codec.ByteToMessageDecoder;
24  import io.netty.handler.codec.CorruptedFrameException;
25  import io.netty.handler.codec.TooLongFrameException;
26  import io.netty.handler.codec.http.websocketx.WebSocket08FrameDecoder.State;
27  import io.netty.util.internal.logging.InternalLogger;
28  import io.netty.util.internal.logging.InternalLoggerFactory;
29  
30  import java.util.List;
31  
32  import static io.netty.buffer.ByteBufUtil.readBytes;
33  
34  /**
35   *
36   */
37  public class Utf8FrameValidator extends ChannelHandlerAdapter {
38  
39      private int fragmentedFramesCount;
40      private Utf8Validator utf8Validator;
41  
42      @Override
43      public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
44          if (msg instanceof WebSocketFrame) {
45              WebSocketFrame frame = (WebSocketFrame) msg;
46  
47              // Processing for possible fragmented messages for text and binary
48              // frames
49              if (((WebSocketFrame) msg).isFinalFragment()) {
50                  // Final frame of the sequence. Apparently ping frames are
51                  // allowed in the middle of a fragmented message
52                  if (!(frame instanceof PingWebSocketFrame)) {
53                      fragmentedFramesCount = 0;
54  
55                      // Check text for UTF8 correctness
56                      if ((frame instanceof TextWebSocketFrame) ||
57                              (utf8Validator != null && utf8Validator.isChecking())) {
58                          // Check UTF-8 correctness for this payload
59                          checkUTF8String(ctx, frame.content());
60  
61                          // This does a second check to make sure UTF-8
62                          // correctness for entire text message
63                          utf8Validator.finish();
64                      }
65                  }
66              } else {
67                  // Not final frame so we can expect more frames in the
68                  // fragmented sequence
69                  if (fragmentedFramesCount == 0) {
70                      // First text or binary frame for a fragmented set
71                      if (frame instanceof TextWebSocketFrame) {
72                          checkUTF8String(ctx, frame.content());
73                      }
74                  } else {
75                      // Subsequent frames - only check if init frame is text
76                      if (utf8Validator != null && utf8Validator.isChecking()) {
77                          checkUTF8String(ctx, frame.content());
78                      }
79                  }
80  
81                  // Increment counter
82                  fragmentedFramesCount++;
83              }
84          }
85  
86          super.channelRead(ctx, msg);
87      }
88  
89      private void checkUTF8String(ChannelHandlerContext ctx, ByteBuf buffer) {
90          try {
91              if (utf8Validator == null) {
92                  utf8Validator = new Utf8Validator();
93              }
94              utf8Validator.check(buffer);
95          } catch (CorruptedFrameException ex) {
96              if (ctx.channel().isActive()) {
97                  ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(ChannelFutureListener.CLOSE);
98              }
99          }
100     }
101 
102 }