1 /*
2 * Copyright 2019 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 * https://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 /*
17 * Adaptation of https://bjoern.hoehrmann.de/utf-8/decoder/dfa/
18 *
19 * Copyright (c) 2008-2009 Bjoern Hoehrmann <bjoern@hoehrmann.de>
20 *
21 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
22 * and associated documentation files (the "Software"), to deal in the Software without restriction,
23 * including without limitation the rights to use, copy, modify, merge, publish, distribute,
24 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
25 * furnished to do so, subject to the following conditions:
26 *
27 * The above copyright notice and this permission notice shall be included in all copies or
28 * substantial portions of the Software.
29 *
30 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
31 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
32 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
33 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
34 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
35 */
36 package io.netty.handler.codec.http.websocketx;
37
38 import io.netty.buffer.ByteBuf;
39 import io.netty.util.ByteProcessor;
40
41 /**
42 * Checks UTF8 bytes for validity
43 */
44 final class Utf8Validator implements ByteProcessor {
45 private static final int UTF8_ACCEPT = 0;
46 private static final int UTF8_REJECT = 12;
47
48 private static final byte[] TYPES = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
49 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
50 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
51 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
52 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1,
53 1, 1, 1, 1, 1, 1, 1, 1, 1, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 7, 7, 7, 7,
54 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8,
55 8, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
56 2, 2, 10, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 3, 3, 11, 6, 6, 6, 5, 8, 8, 8, 8, 8,
57 8, 8, 8, 8, 8, 8 };
58
59 private static final byte[] STATES = { 0, 12, 24, 36, 60, 96, 84, 12, 12, 12, 48, 72, 12, 12,
60 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 0, 12, 12, 12, 12, 12, 0, 12, 0, 12, 12,
61 12, 24, 12, 12, 12, 12, 12, 24, 12, 24, 12, 12, 12, 12, 12, 12, 12, 12, 12, 24, 12, 12,
62 12, 12, 12, 24, 12, 12, 12, 12, 12, 12, 12, 24, 12, 12, 12, 12, 12, 12, 12, 12, 12, 36,
63 12, 36, 12, 12, 12, 36, 12, 12, 12, 12, 12, 36, 12, 36, 12, 12, 12, 36, 12, 12, 12, 12,
64 12, 12, 12, 12, 12, 12 };
65
66 @SuppressWarnings("RedundantFieldInitialization")
67 private int state = UTF8_ACCEPT;
68 private int codep;
69 private boolean checking;
70
71 public void check(ByteBuf buffer) {
72 checking = true;
73 buffer.forEachByte(this);
74 }
75
76 void check(ByteBuf buffer, int index, int length) {
77 checking = true;
78 buffer.forEachByte(index, length, this);
79 }
80
81 public void finish() {
82 checking = false;
83 codep = 0;
84 if (state != UTF8_ACCEPT) {
85 state = UTF8_ACCEPT;
86 throw new CorruptedWebSocketFrameException(
87 WebSocketCloseStatus.INVALID_PAYLOAD_DATA, "bytes are not UTF-8");
88 }
89 }
90
91 @Override
92 public boolean process(byte b) throws Exception {
93 byte type = TYPES[b & 0xFF];
94
95 codep = state != UTF8_ACCEPT ? b & 0x3f | codep << 6 : 0xff >> type & b;
96
97 state = STATES[state + type];
98
99 if (state == UTF8_REJECT) {
100 checking = false;
101 throw new CorruptedWebSocketFrameException(
102 WebSocketCloseStatus.INVALID_PAYLOAD_DATA, "bytes are not UTF-8");
103 }
104 return true;
105 }
106
107 public boolean isChecking() {
108 return checking;
109 }
110 }
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