net/server/web_socket.cc

   1 // Copyright (c) 2012 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 #include "net/server/web_socket.h"
   6
   7 #include <limits>
   8
   9 #include "base/base64.h"
  10 #include "base/rand_util.h"
  11 #include "base/logging.h"
  12 #include "base/md5.h"
  13 #include "base/sha1.h"
  14 #include "base/strings/string_number_conversions.h"
  15 #include "base/strings/stringprintf.h"
  16 #include "base/sys_byteorder.h"
  17 #include "net/server/http_connection.h"
  18 #include "net/server/http_server.h"
  19 #include "net/server/http_server_request_info.h"
  20 #include "net/server/http_server_response_info.h"
  21
  22 namespace net {
  23
  24 namespace {
  25
  26 static uint32 WebSocketKeyFingerprint(const std::string& str) {
  27   std::string result;
  28   const char* p_char = str.c_str();
  29   int length = str.length();
  30   int spaces = 0;
  31   for (int i = 0; i < length; ++i) {
  32     if (p_char[i] >= '0' && p_char[i] <= '9')
  33       result.append(&p_char[i], 1);
  34     else if (p_char[i] == ' ')
  35       spaces++;
  36   }
  37   if (spaces == 0)
  38     return 0;
  39   int64 number = 0;
  40   if (!base::StringToInt64(result, &number))
  41     return 0;
  42   return base::HostToNet32(static_cast<uint32>(number / spaces));
  43 }
  44
  45 class WebSocketHixie76 : public net::WebSocket {
  46  public:
  47   static net::WebSocket* Create(HttpServer* server,
  48                                 HttpConnection* connection,
  49                                 const HttpServerRequestInfo& request,
  50                                 size_t* pos) {
  51     if (connection->read_buf()->GetSize() <
  52         static_cast<int>(*pos + kWebSocketHandshakeBodyLen))
  53       return NULL;
  54     return new WebSocketHixie76(server, connection, request, pos);
  55   }
  56
  57   void Accept(const HttpServerRequestInfo& request) override {
  58     std::string key1 = request.GetHeaderValue("sec-websocket-key1");
  59     std::string key2 = request.GetHeaderValue("sec-websocket-key2");
  60
  61     uint32 fp1 = WebSocketKeyFingerprint(key1);
  62     uint32 fp2 = WebSocketKeyFingerprint(key2);
  63
  64     char data[16];
  65     memcpy(data, &fp1, 4);
  66     memcpy(data + 4, &fp2, 4);
  67     memcpy(data + 8, &key3_[0], 8);
  68
  69     base::MD5Digest digest;
  70     base::MD5Sum(data, 16, &digest);
  71
  72     std::string origin = request.GetHeaderValue("origin");
  73     std::string host = request.GetHeaderValue("host");
  74     std::string location = "ws://" + host + request.path;
  75     server_->SendRaw(
  76         connection_->id(),
  77         base::StringPrintf("HTTP/1.1 101 WebSocket Protocol Handshake\r\n"
  78                            "Upgrade: WebSocket\r\n"
  79                            "Connection: Upgrade\r\n"
  80                            "Sec-WebSocket-Origin: %s\r\n"
  81                            "Sec-WebSocket-Location: %s\r\n"
  82                            "\r\n",
  83                            origin.c_str(),
  84                            location.c_str()));
  85     server_->SendRaw(connection_->id(),
  86                      std::string(reinterpret_cast<char*>(digest.a), 16));
  87   }
  88
  89   ParseResult Read(std::string* message) override {
  90     DCHECK(message);
  91     HttpConnection::ReadIOBuffer* read_buf = connection_->read_buf();
  92     if (read_buf->StartOfBuffer()[0])
  93       return FRAME_ERROR;
  94
  95     base::StringPiece data(read_buf->StartOfBuffer(), read_buf->GetSize());
  96     size_t pos = data.find('\377', 1);
  97     if (pos == base::StringPiece::npos)
  98       return FRAME_INCOMPLETE;
  99
 100     message->assign(data.data() + 1, pos - 1);
 101     read_buf->DidConsume(pos + 1);
 102
 103     return FRAME_OK;
 104   }
 105
 106   void Send(const std::string& message) override {
 107     char message_start = 0;
 108     char message_end = -1;
 109     server_->SendRaw(connection_->id(), std::string(1, message_start));
 110     server_->SendRaw(connection_->id(), message);
 111     server_->SendRaw(connection_->id(), std::string(1, message_end));
 112   }
 113
 114  private:
 115   static const int kWebSocketHandshakeBodyLen;
 116
 117   WebSocketHixie76(HttpServer* server,
 118                    HttpConnection* connection,
 119                    const HttpServerRequestInfo& request,
 120                    size_t* pos)
 121       : WebSocket(server, connection) {
 122     std::string key1 = request.GetHeaderValue("sec-websocket-key1");
 123     std::string key2 = request.GetHeaderValue("sec-websocket-key2");
 124
 125     if (key1.empty()) {
 126       server->SendResponse(
 127           connection->id(),
 128           HttpServerResponseInfo::CreateFor500(
 129               "Invalid request format. Sec-WebSocket-Key1 is empty or isn't "
 130               "specified."));
 131       return;
 132     }
 133
 134     if (key2.empty()) {
 135       server->SendResponse(
 136           connection->id(),
 137           HttpServerResponseInfo::CreateFor500(
 138               "Invalid request format. Sec-WebSocket-Key2 is empty or isn't "
 139               "specified."));
 140       return;
 141     }
 142
 143     key3_.assign(connection->read_buf()->StartOfBuffer() + *pos,
 144                  kWebSocketHandshakeBodyLen);
 145     *pos += kWebSocketHandshakeBodyLen;
 146   }
 147
 148   std::string key3_;
 149
 150   DISALLOW_COPY_AND_ASSIGN(WebSocketHixie76);
 151 };
 152
 153 const int WebSocketHixie76::kWebSocketHandshakeBodyLen = 8;
 154
 155
 156 // Constants for hybi-10 frame format.
 157
 158 typedef int OpCode;
 159
 160 const OpCode kOpCodeContinuation = 0x0;
 161 const OpCode kOpCodeText = 0x1;
 162 const OpCode kOpCodeBinary = 0x2;
 163 const OpCode kOpCodeClose = 0x8;
 164 const OpCode kOpCodePing = 0x9;
 165 const OpCode kOpCodePong = 0xA;
 166
 167 const unsigned char kFinalBit = 0x80;
 168 const unsigned char kReserved1Bit = 0x40;
 169 const unsigned char kReserved2Bit = 0x20;
 170 const unsigned char kReserved3Bit = 0x10;
 171 const unsigned char kOpCodeMask = 0xF;
 172 const unsigned char kMaskBit = 0x80;
 173 const unsigned char kPayloadLengthMask = 0x7F;
 174
 175 const size_t kMaxSingleBytePayloadLength = 125;
 176 const size_t kTwoBytePayloadLengthField = 126;
 177 const size_t kEightBytePayloadLengthField = 127;
 178 const size_t kMaskingKeyWidthInBytes = 4;
 179
 180 class WebSocketHybi17 : public WebSocket {
 181  public:
 182   static WebSocket* Create(HttpServer* server,
 183                            HttpConnection* connection,
 184                            const HttpServerRequestInfo& request,
 185                            size_t* pos) {
 186     std::string version = request.GetHeaderValue("sec-websocket-version");
 187     if (version != "8" && version != "13")
 188       return NULL;
 189
 190     std::string key = request.GetHeaderValue("sec-websocket-key");
 191     if (key.empty()) {
 192       server->SendResponse(
 193           connection->id(),
 194           HttpServerResponseInfo::CreateFor500(
 195               "Invalid request format. Sec-WebSocket-Key is empty or isn't "
 196               "specified."));
 197       return NULL;
 198     }
 199     return new WebSocketHybi17(server, connection, request, pos);
 200   }
 201
 202   void Accept(const HttpServerRequestInfo& request) override {
 203     static const char* const kWebSocketGuid =
 204         "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
 205     std::string key = request.GetHeaderValue("sec-websocket-key");
 206     std::string data = base::StringPrintf("%s%s", key.c_str(), kWebSocketGuid);
 207     std::string encoded_hash;
 208     base::Base64Encode(base::SHA1HashString(data), &encoded_hash);
 209
 210     server_->SendRaw(
 211         connection_->id(),
 212         base::StringPrintf("HTTP/1.1 101 WebSocket Protocol Handshake\r\n"
 213                            "Upgrade: WebSocket\r\n"
 214                            "Connection: Upgrade\r\n"
 215                            "Sec-WebSocket-Accept: %s\r\n"
 216                            "\r\n",
 217                            encoded_hash.c_str()));
 218   }
 219
 220   ParseResult Read(std::string* message) override {
 221     HttpConnection::ReadIOBuffer* read_buf = connection_->read_buf();
 222     base::StringPiece frame(read_buf->StartOfBuffer(), read_buf->GetSize());
 223     int bytes_consumed = 0;
 224     ParseResult result =
 225         WebSocket::DecodeFrameHybi17(frame, true, &bytes_consumed, message);
 226     if (result == FRAME_OK)
 227       read_buf->DidConsume(bytes_consumed);
 228     if (result == FRAME_CLOSE)
 229       closed_ = true;
 230     return result;
 231   }
 232
 233   void Send(const std::string& message) override {
 234     if (closed_)
 235       return;
 236     server_->SendRaw(connection_->id(),
 237                      WebSocket::EncodeFrameHybi17(message, 0));
 238   }
 239
 240  private:
 241   WebSocketHybi17(HttpServer* server,
 242                   HttpConnection* connection,
 243                   const HttpServerRequestInfo& request,
 244                   size_t* pos)
 245       : WebSocket(server, connection),
 246         op_code_(0),
 247         final_(false),
 248         reserved1_(false),
 249         reserved2_(false),
 250         reserved3_(false),
 251         masked_(false),
 252         payload_(0),
 253         payload_length_(0),
 254         frame_end_(0),
 255         closed_(false) {
 256   }
 257
 258   OpCode op_code_;
 259   bool final_;
 260   bool reserved1_;
 261   bool reserved2_;
 262   bool reserved3_;
 263   bool masked_;
 264   const char* payload_;
 265   size_t payload_length_;
 266   const char* frame_end_;
 267   bool closed_;
 268
 269   DISALLOW_COPY_AND_ASSIGN(WebSocketHybi17);
 270 };
 271
 272 }  // anonymous namespace
 273
 274 WebSocket* WebSocket::CreateWebSocket(HttpServer* server,
 275                                       HttpConnection* connection,
 276                                       const HttpServerRequestInfo& request,
 277                                       size_t* pos) {
 278   WebSocket* socket = WebSocketHybi17::Create(server, connection, request, pos);
 279   if (socket)
 280     return socket;
 281
 282   return WebSocketHixie76::Create(server, connection, request, pos);
 283 }
 284
 285 // static
 286 WebSocket::ParseResult WebSocket::DecodeFrameHybi17(
 287     const base::StringPiece& frame,
 288     bool client_frame,
 289     int* bytes_consumed,
 290     std::string* output) {
 291   size_t data_length = frame.length();
 292   if (data_length < 2)
 293     return FRAME_INCOMPLETE;
 294
 295   const char* buffer_begin = const_cast<char*>(frame.data());
 296   const char* p = buffer_begin;
 297   const char* buffer_end = p + data_length;
 298
 299   unsigned char first_byte = *p++;
 300   unsigned char second_byte = *p++;
 301
 302   bool final = (first_byte & kFinalBit) != 0;
 303   bool reserved1 = (first_byte & kReserved1Bit) != 0;
 304   bool reserved2 = (first_byte & kReserved2Bit) != 0;
 305   bool reserved3 = (first_byte & kReserved3Bit) != 0;
 306   int op_code = first_byte & kOpCodeMask;
 307   bool masked = (second_byte & kMaskBit) != 0;
 308   if (!final || reserved1 || reserved2 || reserved3)
 309     return FRAME_ERROR;  // Extensions and not supported.
 310
 311   bool closed = false;
 312   switch (op_code) {
 313   case kOpCodeClose:
 314     closed = true;
 315     break;
 316   case kOpCodeText:
 317     break;
 318   case kOpCodeBinary: // We don't support binary frames yet.
 319   case kOpCodeContinuation: // We don't support binary frames yet.
 320   case kOpCodePing: // We don't support binary frames yet.
 321   case kOpCodePong: // We don't support binary frames yet.
 322   default:
 323     return FRAME_ERROR;
 324   }
 325
 326   if (client_frame && !masked) // In Hybi-17 spec client MUST mask his frame.
 327     return FRAME_ERROR;
 328
 329   uint64 payload_length64 = second_byte & kPayloadLengthMask;
 330   if (payload_length64 > kMaxSingleBytePayloadLength) {
 331     int extended_payload_length_size;
 332     if (payload_length64 == kTwoBytePayloadLengthField)
 333       extended_payload_length_size = 2;
 334     else {
 335       DCHECK(payload_length64 == kEightBytePayloadLengthField);
 336       extended_payload_length_size = 8;
 337     }
 338     if (buffer_end - p < extended_payload_length_size)
 339       return FRAME_INCOMPLETE;
 340     payload_length64 = 0;
 341     for (int i = 0; i < extended_payload_length_size; ++i) {
 342       payload_length64 <<= 8;
 343       payload_length64 |= static_cast<unsigned char>(*p++);
 344     }
 345   }
 346
 347   size_t actual_masking_key_length = masked ? kMaskingKeyWidthInBytes : 0;
 348   static const uint64 max_payload_length = 0x7FFFFFFFFFFFFFFFull;
 349   static size_t max_length = std::numeric_limits<size_t>::max();
 350   if (payload_length64 > max_payload_length ||
 351       payload_length64 + actual_masking_key_length > max_length) {
 352     // WebSocket frame length too large.
 353     return FRAME_ERROR;
 354   }
 355   size_t payload_length = static_cast<size_t>(payload_length64);
 356
 357   size_t total_length = actual_masking_key_length + payload_length;
 358   if (static_cast<size_t>(buffer_end - p) < total_length)
 359     return FRAME_INCOMPLETE;
 360
 361   if (masked) {
 362     output->resize(payload_length);
 363     const char* masking_key = p;
 364     char* payload = const_cast<char*>(p + kMaskingKeyWidthInBytes);
 365     for (size_t i = 0; i < payload_length; ++i)  // Unmask the payload.
 366       (*output)[i] = payload[i] ^ masking_key[i % kMaskingKeyWidthInBytes];
 367   } else {
 368     output->assign(p, p + payload_length);
 369   }
 370
 371   size_t pos = p + actual_masking_key_length + payload_length - buffer_begin;
 372   *bytes_consumed = pos;
 373   return closed ? FRAME_CLOSE : FRAME_OK;
 374 }
 375
 376 // static
 377 std::string WebSocket::EncodeFrameHybi17(const std::string& message,
 378                                          int masking_key) {
 379   std::vector<char> frame;
 380   OpCode op_code = kOpCodeText;
 381   size_t data_length = message.length();
 382
 383   frame.push_back(kFinalBit | op_code);
 384   char mask_key_bit = masking_key != 0 ? kMaskBit : 0;
 385   if (data_length <= kMaxSingleBytePayloadLength)
 386     frame.push_back(data_length | mask_key_bit);
 387   else if (data_length <= 0xFFFF) {
 388     frame.push_back(kTwoBytePayloadLengthField | mask_key_bit);
 389     frame.push_back((data_length & 0xFF00) >> 8);
 390     frame.push_back(data_length & 0xFF);
 391   } else {
 392     frame.push_back(kEightBytePayloadLengthField | mask_key_bit);
 393     char extended_payload_length[8];
 394     size_t remaining = data_length;
 395     // Fill the length into extended_payload_length in the network byte order.
 396     for (int i = 0; i < 8; ++i) {
 397       extended_payload_length[7 - i] = remaining & 0xFF;
 398       remaining >>= 8;
 399     }
 400     frame.insert(frame.end(),
 401                  extended_payload_length,
 402                  extended_payload_length + 8);
 403     DCHECK(!remaining);
 404   }
 405
 406   const char* data = const_cast<char*>(message.data());
 407   if (masking_key != 0) {
 408     const char* mask_bytes = reinterpret_cast<char*>(&masking_key);
 409     frame.insert(frame.end(), mask_bytes, mask_bytes + 4);
 410     for (size_t i = 0; i < data_length; ++i)  // Mask the payload.
 411       frame.push_back(data[i] ^ mask_bytes[i % kMaskingKeyWidthInBytes]);
 412   } else {
 413     frame.insert(frame.end(), data, data + data_length);
 414   }
 415   return std::string(&frame[0], frame.size());
 416 }
 417
 418 WebSocket::WebSocket(HttpServer* server, HttpConnection* connection)
 419     : server_(server),
 420       connection_(connection) {
 421 }
 422
 423 }  // namespace net