// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Derived from:
// mozilla/netwerk/protocol/http/src/nsHttpChunkedDecoder.cpp
// The license block is:
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla.
*
* The Initial Developer of the Original Code is
* Netscape Communications.
* Portions created by the Initial Developer are Copyright (C) 2001
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Darin Fisher <darin@netscape.com> (original author)
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include "net/http/http_chunked_decoder.h"
#include <algorithm>
#include "base/logging.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_piece.h"
#include "base/strings/string_util.h"
#include "net/base/net_errors.h"
namespace net {
// Absurdly long size to avoid imposing a constraint on chunked encoding
// extensions.
const size_t HttpChunkedDecoder::kMaxLineBufLen = 16384;
HttpChunkedDecoder::HttpChunkedDecoder()
: chunk_remaining_(0),
chunk_terminator_remaining_(false),
reached_last_chunk_(false),
reached_eof_(false),
bytes_after_eof_(0) {
}
int HttpChunkedDecoder::FilterBuf(char* buf, int buf_len) {
int result = 0;
while (buf_len) {
if (chunk_remaining_) {
int num = std::min(chunk_remaining_, buf_len);
buf_len -= num;
chunk_remaining_ -= num;
result += num;
buf += num;
// After each chunk's data there should be a CRLF
if (!chunk_remaining_)
chunk_terminator_remaining_ = true;
continue;
} else if (reached_eof_) {
bytes_after_eof_ += buf_len;
break; // Done!
}
int bytes_consumed = ScanForChunkRemaining(buf, buf_len);
if (bytes_consumed < 0)
return bytes_consumed; // Error
buf_len -= bytes_consumed;
if (buf_len)
memmove(buf, buf + bytes_consumed, buf_len);
}
return result;
}
int HttpChunkedDecoder::ScanForChunkRemaining(const char* buf, int buf_len) {
DCHECK_EQ(0, chunk_remaining_);
DCHECK_GT(buf_len, 0);
int bytes_consumed = 0;
size_t index_of_lf = base::StringPiece(buf, buf_len).find('\n');
if (index_of_lf != base::StringPiece::npos) {
buf_len = static_cast<int>(index_of_lf);
if (buf_len && buf[buf_len - 1] == '\r') // Eliminate a preceding CR.
buf_len--;
bytes_consumed = static_cast<int>(index_of_lf) + 1;
// Make buf point to the full line buffer to parse.
if (!line_buf_.empty()) {
line_buf_.append(buf, buf_len);
buf = line_buf_.data();
buf_len = static_cast<int>(line_buf_.size());
}
if (reached_last_chunk_) {
if (buf_len)
DVLOG(1) << "ignoring http trailer";
else
reached_eof_ = true;
} else if (chunk_terminator_remaining_) {
if (buf_len) {
DLOG(ERROR) << "chunk data not terminated properly";
return ERR_INVALID_CHUNKED_ENCODING;
}
chunk_terminator_remaining_ = false;
} else if (buf_len) {
// Ignore any chunk-extensions.
size_t index_of_semicolon = base::StringPiece(buf, buf_len).find(';');
if (index_of_semicolon != base::StringPiece::npos)
buf_len = static_cast<int>(index_of_semicolon);
if (!ParseChunkSize(buf, buf_len, &chunk_remaining_)) {
DLOG(ERROR) << "Failed parsing HEX from: " <<
std::string(buf, buf_len);
return ERR_INVALID_CHUNKED_ENCODING;
}
if (chunk_remaining_ == 0)
reached_last_chunk_ = true;
} else {
DLOG(ERROR) << "missing chunk-size";
return ERR_INVALID_CHUNKED_ENCODING;
}
line_buf_.clear();
} else {
// Save the partial line; wait for more data.
bytes_consumed = buf_len;
// Ignore a trailing CR
if (buf[buf_len - 1] == '\r')
buf_len--;
if (line_buf_.length() + buf_len > kMaxLineBufLen) {
DLOG(ERROR) << "Chunked line length too long";
return ERR_INVALID_CHUNKED_ENCODING;
}
line_buf_.append(buf, buf_len);
}
return bytes_consumed;
}
// While the HTTP 1.1 specification defines chunk-size as 1*HEX
// some sites rely on more lenient parsing.
// http://www.yahoo.com/, for example, pads chunk-size with trailing spaces
// (0x20) to be 7 characters long, such as "819b ".
//
// A comparison of browsers running on WindowsXP shows that
// they will parse the following inputs (egrep syntax):
//
// Let \X be the character class for a hex digit: [0-9a-fA-F]
//
// RFC 2616: ^\X+$
// IE7: ^\X+[^\X]*$
// Safari 3.1: ^[\t\r ]*\X+[\t ]*$
// Firefox 3: ^[\t\f\v\r ]*[+]?(0x)?\X+[^\X]*$
// Opera 9.51: ^[\t\f\v ]*[+]?(0x)?\X+[^\X]*$
//
// Our strategy is to be as strict as possible, while not breaking
// known sites.
//
// Us: ^\X+[ ]*$
bool HttpChunkedDecoder::ParseChunkSize(const char* start, int len, int* out) {
DCHECK_GE(len, 0);
// Strip trailing spaces
while (len && start[len - 1] == ' ')
len--;
// Be more restrictive than HexStringToInt;
// don't allow inputs with leading "-", "+", "0x", "0X"
base::StringPiece chunk_size(start, len);
if (chunk_size.find_first_not_of("0123456789abcdefABCDEF")
!= base::StringPiece::npos) {
return false;
}
int parsed_number;
bool ok = base::HexStringToInt(chunk_size, &parsed_number);
if (ok && parsed_number >= 0) {
*out = parsed_number;
return true;
}
return false;
}
} // namespace net