1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212
|
// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "net/websockets/websocket_frame_parser.h"
#include <algorithm>
#include <ostream>
#include <utility>
#include <vector>
#include "base/check.h"
#include "base/check_op.h"
#include "base/containers/extend.h"
#include "base/containers/span.h"
#include "base/logging.h"
#include "base/numerics/byte_conversions.h"
#include "base/numerics/safe_conversions.h"
#include "net/websockets/websocket_frame.h"
namespace {
constexpr uint8_t kFinalBit = 0x80;
constexpr uint8_t kReserved1Bit = 0x40;
constexpr uint8_t kReserved2Bit = 0x20;
constexpr uint8_t kReserved3Bit = 0x10;
constexpr uint8_t kOpCodeMask = 0xF;
constexpr uint8_t kMaskBit = 0x80;
constexpr uint8_t kPayloadLengthMask = 0x7F;
constexpr uint64_t kMaxPayloadLengthWithoutExtendedLengthField = 125;
constexpr uint64_t kPayloadLengthWithTwoByteExtendedLengthField = 126;
constexpr uint64_t kPayloadLengthWithEightByteExtendedLengthField = 127;
constexpr size_t kMaximumFrameHeaderSize =
net::WebSocketFrameHeader::kBaseHeaderSize +
net::WebSocketFrameHeader::kMaximumExtendedLengthSize +
net::WebSocketFrameHeader::kMaskingKeyLength;
} // namespace.
namespace net {
WebSocketFrameParser::WebSocketFrameParser() = default;
WebSocketFrameParser::~WebSocketFrameParser() = default;
bool WebSocketFrameParser::Decode(
base::span<uint8_t> data_span,
std::vector<std::unique_ptr<WebSocketFrameChunk>>* frame_chunks) {
if (websocket_error_ != kWebSocketNormalClosure) {
return false;
}
if (data_span.empty()) {
return true;
}
// If we have incomplete frame header, try to decode a header combining with
// |data|.
bool first_chunk = false;
if (incomplete_header_buffer_.size() > 0) {
DCHECK(!current_frame_header_.get());
const size_t original_size = incomplete_header_buffer_.size();
DCHECK_LE(original_size, kMaximumFrameHeaderSize);
base::Extend(
incomplete_header_buffer_,
data_span.first(std::min(data_span.size(),
kMaximumFrameHeaderSize - original_size)));
const size_t consumed = DecodeFrameHeader(incomplete_header_buffer_);
if (websocket_error_ != kWebSocketNormalClosure)
return false;
if (!current_frame_header_.get())
return true;
DCHECK_GE(consumed, original_size);
data_span = data_span.subspan(consumed - original_size);
incomplete_header_buffer_.clear();
first_chunk = true;
}
DCHECK(incomplete_header_buffer_.empty());
while (data_span.size() > 0 || first_chunk) {
if (!current_frame_header_.get()) {
const size_t consumed = DecodeFrameHeader(data_span);
if (websocket_error_ != kWebSocketNormalClosure)
return false;
// If frame header is incomplete, then carry over the remaining
// data to the next round of Decode().
if (!current_frame_header_.get()) {
DCHECK(!consumed);
base::Extend(incomplete_header_buffer_, data_span);
// Sanity check: the size of carried-over data should not exceed
// the maximum possible length of a frame header.
DCHECK_LT(incomplete_header_buffer_.size(), kMaximumFrameHeaderSize);
return true;
}
DCHECK_GE(data_span.size(), consumed);
data_span = data_span.subspan(consumed);
first_chunk = true;
}
DCHECK(incomplete_header_buffer_.empty());
std::unique_ptr<WebSocketFrameChunk> frame_chunk =
DecodeFramePayload(first_chunk, &data_span);
first_chunk = false;
DCHECK(frame_chunk.get());
frame_chunks->push_back(std::move(frame_chunk));
}
return true;
}
size_t WebSocketFrameParser::DecodeFrameHeader(base::span<const uint8_t> data) {
DVLOG(3) << "DecodeFrameHeader buffer size:"
<< ", data size:" << data.size();
typedef WebSocketFrameHeader::OpCode OpCode;
DCHECK(!current_frame_header_.get());
// Header needs 2 bytes at minimum.
if (data.size() < 2)
return 0;
size_t current = 0;
const uint8_t first_byte = data[current++];
const uint8_t second_byte = data[current++];
const bool final = (first_byte & kFinalBit) != 0;
const bool reserved1 = (first_byte & kReserved1Bit) != 0;
const bool reserved2 = (first_byte & kReserved2Bit) != 0;
const bool reserved3 = (first_byte & kReserved3Bit) != 0;
const OpCode opcode = first_byte & kOpCodeMask;
uint64_t payload_length = second_byte & kPayloadLengthMask;
if (payload_length == kPayloadLengthWithTwoByteExtendedLengthField) {
if (data.size() < current + 2)
return 0;
uint16_t payload_length_16 =
base::U16FromBigEndian(data.subspan(current).first<2>());
current += 2;
payload_length = payload_length_16;
if (payload_length <= kMaxPayloadLengthWithoutExtendedLengthField) {
websocket_error_ = kWebSocketErrorProtocolError;
return 0;
}
} else if (payload_length == kPayloadLengthWithEightByteExtendedLengthField) {
if (data.size() < current + 8)
return 0;
payload_length = base::U64FromBigEndian(data.subspan(current).first<8>());
current += 8;
if (payload_length <= UINT16_MAX ||
payload_length > static_cast<uint64_t>(INT64_MAX)) {
websocket_error_ = kWebSocketErrorProtocolError;
return 0;
}
if (payload_length > static_cast<uint64_t>(INT32_MAX)) {
websocket_error_ = kWebSocketErrorMessageTooBig;
return 0;
}
}
DCHECK_EQ(websocket_error_, kWebSocketNormalClosure);
WebSocketMaskingKey masking_key = {};
const bool masked = (second_byte & kMaskBit) != 0;
static constexpr size_t kMaskingKeyLength =
WebSocketFrameHeader::kMaskingKeyLength;
if (masked) {
if (data.size() < current + kMaskingKeyLength)
return 0;
base::as_writable_byte_span(masking_key.key)
.copy_from(data.subspan(current, kMaskingKeyLength));
current += kMaskingKeyLength;
}
current_frame_header_ = std::make_unique<WebSocketFrameHeader>(opcode);
current_frame_header_->final = final;
current_frame_header_->reserved1 = reserved1;
current_frame_header_->reserved2 = reserved2;
current_frame_header_->reserved3 = reserved3;
current_frame_header_->masked = masked;
current_frame_header_->masking_key = masking_key;
current_frame_header_->payload_length = payload_length;
DCHECK_EQ(0u, frame_offset_);
return current;
}
std::unique_ptr<WebSocketFrameChunk> WebSocketFrameParser::DecodeFramePayload(
bool first_chunk,
base::span<uint8_t>* data) {
// The cast here is safe because |payload_length| is already checked to be
// less than std::numeric_limits<int>::max() when the header is parsed.
const auto chunk_data_size = static_cast<uint64_t>(
std::min(uint64_t{data->size()},
current_frame_header_->payload_length - frame_offset_));
auto frame_chunk = std::make_unique<WebSocketFrameChunk>();
if (first_chunk) {
frame_chunk->header = current_frame_header_->Clone();
}
frame_chunk->final_chunk = false;
if (chunk_data_size) {
const auto split_point = base::checked_cast<size_t>(chunk_data_size);
frame_chunk->payload = base::as_writable_chars(data->first(split_point));
*data = data->subspan(split_point);
frame_offset_ += chunk_data_size;
}
DCHECK_LE(frame_offset_, current_frame_header_->payload_length);
if (frame_offset_ == current_frame_header_->payload_length) {
frame_chunk->final_chunk = true;
current_frame_header_.reset();
frame_offset_ = 0;
}
return frame_chunk;
}
} // namespace net
|