1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 // Derived from:
6 // mozilla/netwerk/protocol/http/src/nsHttpChunkedDecoder.cpp
7 // The license block is:
8 /* ***** BEGIN LICENSE BLOCK *****
9 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
10 *
11 * The contents of this file are subject to the Mozilla Public License Version
12 * 1.1 (the "License"); you may not use this file except in compliance with
13 * the License. You may obtain a copy of the License at
14 * http://www.mozilla.org/MPL/
15 *
16 * Software distributed under the License is distributed on an "AS IS" basis,
17 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
18 * for the specific language governing rights and limitations under the
19 * License.
20 *
21 * The Original Code is Mozilla.
22 *
23 * The Initial Developer of the Original Code is
24 * Netscape Communications.
25 * Portions created by the Initial Developer are Copyright (C) 2001
26 * the Initial Developer. All Rights Reserved.
27 *
28 * Contributor(s):
29 * Darin Fisher <darin@netscape.com> (original author)
30 *
31 * Alternatively, the contents of this file may be used under the terms of
32 * either the GNU General Public License Version 2 or later (the "GPL"), or
33 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
34 * in which case the provisions of the GPL or the LGPL are applicable instead
35 * of those above. If you wish to allow use of your version of this file only
36 * under the terms of either the GPL or the LGPL, and not to allow others to
37 * use your version of this file under the terms of the MPL, indicate your
38 * decision by deleting the provisions above and replace them with the notice
39 * and other provisions required by the GPL or the LGPL. If you do not delete
40 * the provisions above, a recipient may use your version of this file under
41 * the terms of any one of the MPL, the GPL or the LGPL.
42 *
43 * ***** END LICENSE BLOCK ***** */
44
45 #include "net/http/http_chunked_decoder.h"
46
47 #include <algorithm>
48
49 #include "base/logging.h"
50 #include "base/strings/string_number_conversions.h"
51 #include "base/strings/string_piece.h"
52 #include "base/strings/string_util.h"
53 #include "net/base/net_errors.h"
54
55 namespace net {
56
57 // Absurdly long size to avoid imposing a constraint on chunked encoding
58 // extensions.
59 const size_t HttpChunkedDecoder::kMaxLineBufLen = 16384;
60
HttpChunkedDecoder()61 HttpChunkedDecoder::HttpChunkedDecoder()
62 : chunk_remaining_(0),
63 chunk_terminator_remaining_(false),
64 reached_last_chunk_(false),
65 reached_eof_(false),
66 bytes_after_eof_(0) {
67 }
68
FilterBuf(char * buf,int buf_len)69 int HttpChunkedDecoder::FilterBuf(char* buf, int buf_len) {
70 int result = 0;
71
72 while (buf_len) {
73 if (chunk_remaining_) {
74 int num = std::min(chunk_remaining_, buf_len);
75
76 buf_len -= num;
77 chunk_remaining_ -= num;
78
79 result += num;
80 buf += num;
81
82 // After each chunk's data there should be a CRLF
83 if (!chunk_remaining_)
84 chunk_terminator_remaining_ = true;
85 continue;
86 } else if (reached_eof_) {
87 bytes_after_eof_ += buf_len;
88 break; // Done!
89 }
90
91 int bytes_consumed = ScanForChunkRemaining(buf, buf_len);
92 if (bytes_consumed < 0)
93 return bytes_consumed; // Error
94
95 buf_len -= bytes_consumed;
96 if (buf_len)
97 memmove(buf, buf + bytes_consumed, buf_len);
98 }
99
100 return result;
101 }
102
ScanForChunkRemaining(const char * buf,int buf_len)103 int HttpChunkedDecoder::ScanForChunkRemaining(const char* buf, int buf_len) {
104 DCHECK_EQ(0, chunk_remaining_);
105 DCHECK_GT(buf_len, 0);
106
107 int bytes_consumed = 0;
108
109 size_t index_of_lf = base::StringPiece(buf, buf_len).find('\n');
110 if (index_of_lf != base::StringPiece::npos) {
111 buf_len = static_cast<int>(index_of_lf);
112 if (buf_len && buf[buf_len - 1] == '\r') // Eliminate a preceding CR.
113 buf_len--;
114 bytes_consumed = static_cast<int>(index_of_lf) + 1;
115
116 // Make buf point to the full line buffer to parse.
117 if (!line_buf_.empty()) {
118 line_buf_.append(buf, buf_len);
119 buf = line_buf_.data();
120 buf_len = static_cast<int>(line_buf_.size());
121 }
122
123 if (reached_last_chunk_) {
124 if (buf_len)
125 DVLOG(1) << "ignoring http trailer";
126 else
127 reached_eof_ = true;
128 } else if (chunk_terminator_remaining_) {
129 if (buf_len) {
130 DLOG(ERROR) << "chunk data not terminated properly";
131 return ERR_INVALID_CHUNKED_ENCODING;
132 }
133 chunk_terminator_remaining_ = false;
134 } else if (buf_len) {
135 // Ignore any chunk-extensions.
136 size_t index_of_semicolon = base::StringPiece(buf, buf_len).find(';');
137 if (index_of_semicolon != base::StringPiece::npos)
138 buf_len = static_cast<int>(index_of_semicolon);
139
140 if (!ParseChunkSize(buf, buf_len, &chunk_remaining_)) {
141 DLOG(ERROR) << "Failed parsing HEX from: " <<
142 std::string(buf, buf_len);
143 return ERR_INVALID_CHUNKED_ENCODING;
144 }
145
146 if (chunk_remaining_ == 0)
147 reached_last_chunk_ = true;
148 } else {
149 DLOG(ERROR) << "missing chunk-size";
150 return ERR_INVALID_CHUNKED_ENCODING;
151 }
152 line_buf_.clear();
153 } else {
154 // Save the partial line; wait for more data.
155 bytes_consumed = buf_len;
156
157 // Ignore a trailing CR
158 if (buf[buf_len - 1] == '\r')
159 buf_len--;
160
161 if (line_buf_.length() + buf_len > kMaxLineBufLen) {
162 DLOG(ERROR) << "Chunked line length too long";
163 return ERR_INVALID_CHUNKED_ENCODING;
164 }
165
166 line_buf_.append(buf, buf_len);
167 }
168 return bytes_consumed;
169 }
170
171
172 // While the HTTP 1.1 specification defines chunk-size as 1*HEX
173 // some sites rely on more lenient parsing.
174 // http://www.yahoo.com/, for example, pads chunk-size with trailing spaces
175 // (0x20) to be 7 characters long, such as "819b ".
176 //
177 // A comparison of browsers running on WindowsXP shows that
178 // they will parse the following inputs (egrep syntax):
179 //
180 // Let \X be the character class for a hex digit: [0-9a-fA-F]
181 //
182 // RFC 2616: ^\X+$
183 // IE7: ^\X+[^\X]*$
184 // Safari 3.1: ^[\t\r ]*\X+[\t ]*$
185 // Firefox 3: ^[\t\f\v\r ]*[+]?(0x)?\X+[^\X]*$
186 // Opera 9.51: ^[\t\f\v ]*[+]?(0x)?\X+[^\X]*$
187 //
188 // Our strategy is to be as strict as possible, while not breaking
189 // known sites.
190 //
191 // Us: ^\X+[ ]*$
ParseChunkSize(const char * start,int len,int * out)192 bool HttpChunkedDecoder::ParseChunkSize(const char* start, int len, int* out) {
193 DCHECK_GE(len, 0);
194
195 // Strip trailing spaces
196 while (len && start[len - 1] == ' ')
197 len--;
198
199 // Be more restrictive than HexStringToInt;
200 // don't allow inputs with leading "-", "+", "0x", "0X"
201 base::StringPiece chunk_size(start, len);
202 if (chunk_size.find_first_not_of("0123456789abcdefABCDEF")
203 != base::StringPiece::npos) {
204 return false;
205 }
206
207 int parsed_number;
208 bool ok = base::HexStringToInt(chunk_size, &parsed_number);
209 if (ok && parsed_number >= 0) {
210 *out = parsed_number;
211 return true;
212 }
213 return false;
214 }
215
216 } // namespace net
217