net/quic/test_tools/crypto_test_utils.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/quic/test_tools/crypto_test_utils.h"
   6
   7 #include "net/quic/crypto/channel_id.h"
   8 #include "net/quic/crypto/common_cert_set.h"
   9 #include "net/quic/crypto/crypto_handshake.h"
  10 #include "net/quic/crypto/quic_crypto_server_config.h"
  11 #include "net/quic/crypto/quic_decrypter.h"
  12 #include "net/quic/crypto/quic_encrypter.h"
  13 #include "net/quic/crypto/quic_random.h"
  14 #include "net/quic/quic_clock.h"
  15 #include "net/quic/quic_crypto_client_stream.h"
  16 #include "net/quic/quic_crypto_server_stream.h"
  17 #include "net/quic/quic_crypto_stream.h"
  18 #include "net/quic/quic_server_id.h"
  19 #include "net/quic/test_tools/quic_connection_peer.h"
  20 #include "net/quic/test_tools/quic_test_utils.h"
  21 #include "net/quic/test_tools/simple_quic_framer.h"
  22
  23 using base::StringPiece;
  24 using std::make_pair;
  25 using std::pair;
  26 using std::string;
  27 using std::vector;
  28
  29 namespace net {
  30 namespace test {
  31
  32 namespace {
  33
  34 const char kServerHostname[] = "test.example.com";
  35 const uint16 kServerPort = 80;
  36
  37 // CryptoFramerVisitor is a framer visitor that records handshake messages.
  38 class CryptoFramerVisitor : public CryptoFramerVisitorInterface {
  39  public:
  40   CryptoFramerVisitor()
  41       : error_(false) {
  42   }
  43
  44   void OnError(CryptoFramer* framer) override { error_ = true; }
  45
  46   void OnHandshakeMessage(const CryptoHandshakeMessage& message) override {
  47     messages_.push_back(message);
  48   }
  49
  50   bool error() const {
  51     return error_;
  52   }
  53
  54   const vector<CryptoHandshakeMessage>& messages() const {
  55     return messages_;
  56   }
  57
  58  private:
  59   bool error_;
  60   vector<CryptoHandshakeMessage> messages_;
  61 };
  62
  63 // MovePackets parses crypto handshake messages from packet number
  64 // |*inout_packet_index| through to the last packet (or until a packet fails to
  65 // decrypt) and has |dest_stream| process them. |*inout_packet_index| is updated
  66 // with an index one greater than the last packet processed.
  67 void MovePackets(PacketSavingConnection* source_conn,
  68                  size_t *inout_packet_index,
  69                  QuicCryptoStream* dest_stream,
  70                  PacketSavingConnection* dest_conn) {
  71   SimpleQuicFramer framer(source_conn->supported_versions());
  72   CryptoFramer crypto_framer;
  73   CryptoFramerVisitor crypto_visitor;
  74
  75   // In order to properly test the code we need to perform encryption and
  76   // decryption so that the crypters latch when expected. The crypters are in
  77   // |dest_conn|, but we don't want to try and use them there. Instead we swap
  78   // them into |framer|, perform the decryption with them, and then swap them
  79   // back.
  80   QuicConnectionPeer::SwapCrypters(dest_conn, framer.framer());
  81
  82   crypto_framer.set_visitor(&crypto_visitor);
  83
  84   size_t index = *inout_packet_index;
  85   for (; index < source_conn->encrypted_packets_.size(); index++) {
  86     if (!framer.ProcessPacket(*source_conn->encrypted_packets_[index])) {
  87       // The framer will be unable to decrypt forward-secure packets sent after
  88       // the handshake is complete. Don't treat them as handshake packets.
  89       break;
  90     }
  91
  92     for (vector<QuicStreamFrame>::const_iterator
  93          i =  framer.stream_frames().begin();
  94          i != framer.stream_frames().end(); ++i) {
  95       scoped_ptr<string> frame_data(i->GetDataAsString());
  96       ASSERT_TRUE(crypto_framer.ProcessInput(*frame_data));
  97       ASSERT_FALSE(crypto_visitor.error());
  98     }
  99   }
 100   *inout_packet_index = index;
 101
 102   QuicConnectionPeer::SwapCrypters(dest_conn, framer.framer());
 103
 104   ASSERT_EQ(0u, crypto_framer.InputBytesRemaining());
 105
 106   for (vector<CryptoHandshakeMessage>::const_iterator
 107        i = crypto_visitor.messages().begin();
 108        i != crypto_visitor.messages().end(); ++i) {
 109     dest_stream->OnHandshakeMessage(*i);
 110   }
 111 }
 112
 113 // HexChar parses |c| as a hex character. If valid, it sets |*value| to the
 114 // value of the hex character and returns true. Otherwise it returns false.
 115 bool HexChar(char c, uint8* value) {
 116   if (c >= '0' && c <= '9') {
 117     *value = c - '0';
 118     return true;
 119   }
 120   if (c >= 'a' && c <= 'f') {
 121     *value = c - 'a' + 10;
 122     return true;
 123   }
 124   if (c >= 'A' && c <= 'F') {
 125     *value = c - 'A' + 10;
 126     return true;
 127   }
 128   return false;
 129 }
 130
 131 // A ChannelIDSource that works in asynchronous mode unless the |callback|
 132 // argument to GetChannelIDKey is nullptr.
 133 class AsyncTestChannelIDSource : public ChannelIDSource,
 134                                  public CryptoTestUtils::CallbackSource {
 135  public:
 136   // Takes ownership of |sync_source|, a synchronous ChannelIDSource.
 137   explicit AsyncTestChannelIDSource(ChannelIDSource* sync_source)
 138       : sync_source_(sync_source) {}
 139   ~AsyncTestChannelIDSource() override {}
 140
 141   // ChannelIDSource implementation.
 142   QuicAsyncStatus GetChannelIDKey(const string& hostname,
 143                                   scoped_ptr<ChannelIDKey>* channel_id_key,
 144                                   ChannelIDSourceCallback* callback) override {
 145     // Synchronous mode.
 146     if (!callback) {
 147       return sync_source_->GetChannelIDKey(hostname, channel_id_key, nullptr);
 148     }
 149
 150     // Asynchronous mode.
 151     QuicAsyncStatus status =
 152         sync_source_->GetChannelIDKey(hostname, &channel_id_key_, nullptr);
 153     if (status != QUIC_SUCCESS) {
 154       return QUIC_FAILURE;
 155     }
 156     callback_.reset(callback);
 157     return QUIC_PENDING;
 158   }
 159
 160   // CallbackSource implementation.
 161   void RunPendingCallbacks() override {
 162     if (callback_.get()) {
 163       callback_->Run(&channel_id_key_);
 164       callback_.reset();
 165     }
 166   }
 167
 168  private:
 169   scoped_ptr<ChannelIDSource> sync_source_;
 170   scoped_ptr<ChannelIDSourceCallback> callback_;
 171   scoped_ptr<ChannelIDKey> channel_id_key_;
 172 };
 173
 174 }  // anonymous namespace
 175
 176 CryptoTestUtils::FakeClientOptions::FakeClientOptions()
 177     : dont_verify_certs(false),
 178       channel_id_enabled(false),
 179       channel_id_source_async(false) {
 180 }
 181
 182 // static
 183 int CryptoTestUtils::HandshakeWithFakeServer(
 184     PacketSavingConnection* client_conn,
 185     QuicCryptoClientStream* client) {
 186   PacketSavingConnection* server_conn = new PacketSavingConnection(
 187       Perspective::IS_SERVER, client_conn->supported_versions());
 188   TestSession server_session(server_conn, DefaultQuicConfig());
 189   server_session.InitializeSession();
 190   QuicCryptoServerConfig crypto_config(QuicCryptoServerConfig::TESTING,
 191                                        QuicRandom::GetInstance());
 192
 193   SetupCryptoServerConfigForTest(
 194       server_session.connection()->clock(),
 195       server_session.connection()->random_generator(),
 196       server_session.config(), &crypto_config);
 197
 198   QuicCryptoServerStream server(&crypto_config, &server_session);
 199   server_session.SetCryptoStream(&server);
 200
 201   // The client's handshake must have been started already.
 202   CHECK_NE(0u, client_conn->encrypted_packets_.size());
 203
 204   CommunicateHandshakeMessages(client_conn, client, server_conn, &server);
 205
 206   CompareClientAndServerKeys(client, &server);
 207
 208   return client->num_sent_client_hellos();
 209 }
 210
 211 // static
 212 int CryptoTestUtils::HandshakeWithFakeClient(
 213     PacketSavingConnection* server_conn,
 214     QuicCryptoServerStream* server,
 215     const FakeClientOptions& options) {
 216   PacketSavingConnection* client_conn =
 217       new PacketSavingConnection(Perspective::IS_CLIENT);
 218   // Advance the time, because timers do not like uninitialized times.
 219   client_conn->AdvanceTime(QuicTime::Delta::FromSeconds(1));
 220   TestClientSession client_session(client_conn, DefaultQuicConfig());
 221   QuicCryptoClientConfig crypto_config;
 222
 223   if (!options.dont_verify_certs) {
 224     // TODO(wtc): replace this with ProofVerifierForTesting() when we have
 225     // a working ProofSourceForTesting().
 226     crypto_config.SetProofVerifier(FakeProofVerifierForTesting());
 227   }
 228   bool is_https = false;
 229   AsyncTestChannelIDSource* async_channel_id_source = nullptr;
 230   if (options.channel_id_enabled) {
 231     is_https = true;
 232
 233     ChannelIDSource* source = ChannelIDSourceForTesting();
 234     if (options.channel_id_source_async) {
 235       async_channel_id_source = new AsyncTestChannelIDSource(source);
 236       source = async_channel_id_source;
 237     }
 238     crypto_config.SetChannelIDSource(source);
 239   }
 240   QuicServerId server_id(kServerHostname, kServerPort, is_https,
 241                          PRIVACY_MODE_DISABLED);
 242   QuicCryptoClientStream client(server_id, &client_session,
 243                                 ProofVerifyContextForTesting(),
 244                                 &crypto_config);
 245   client_session.SetCryptoStream(&client);
 246
 247   client.CryptoConnect();
 248   CHECK_EQ(1u, client_conn->encrypted_packets_.size());
 249
 250   CommunicateHandshakeMessagesAndRunCallbacks(
 251       client_conn, &client, server_conn, server, async_channel_id_source);
 252
 253   CompareClientAndServerKeys(&client, server);
 254
 255   if (options.channel_id_enabled) {
 256     scoped_ptr<ChannelIDKey> channel_id_key;
 257     QuicAsyncStatus status = crypto_config.channel_id_source()->GetChannelIDKey(
 258         kServerHostname, &channel_id_key, nullptr);
 259     EXPECT_EQ(QUIC_SUCCESS, status);
 260     EXPECT_EQ(channel_id_key->SerializeKey(),
 261               server->crypto_negotiated_params().channel_id);
 262     EXPECT_EQ(options.channel_id_source_async,
 263               client.WasChannelIDSourceCallbackRun());
 264   }
 265
 266   return client.num_sent_client_hellos();
 267 }
 268
 269 // static
 270 void CryptoTestUtils::SetupCryptoServerConfigForTest(
 271     const QuicClock* clock,
 272     QuicRandom* rand,
 273     QuicConfig* config,
 274     QuicCryptoServerConfig* crypto_config) {
 275   QuicCryptoServerConfig::ConfigOptions options;
 276   options.channel_id_enabled = true;
 277   scoped_ptr<CryptoHandshakeMessage> scfg(
 278       crypto_config->AddDefaultConfig(rand, clock, options));
 279 }
 280
 281 // static
 282 void CryptoTestUtils::CommunicateHandshakeMessages(
 283     PacketSavingConnection* a_conn,
 284     QuicCryptoStream* a,
 285     PacketSavingConnection* b_conn,
 286     QuicCryptoStream* b) {
 287   CommunicateHandshakeMessagesAndRunCallbacks(a_conn, a, b_conn, b, nullptr);
 288 }
 289
 290 // static
 291 void CryptoTestUtils::CommunicateHandshakeMessagesAndRunCallbacks(
 292     PacketSavingConnection* a_conn,
 293     QuicCryptoStream* a,
 294     PacketSavingConnection* b_conn,
 295     QuicCryptoStream* b,
 296     CallbackSource* callback_source) {
 297   size_t a_i = 0, b_i = 0;
 298   while (!a->handshake_confirmed()) {
 299     ASSERT_GT(a_conn->encrypted_packets_.size(), a_i);
 300     VLOG(1) << "Processing " << a_conn->encrypted_packets_.size() - a_i
 301             << " packets a->b";
 302     MovePackets(a_conn, &a_i, b, b_conn);
 303     if (callback_source) {
 304       callback_source->RunPendingCallbacks();
 305     }
 306
 307     ASSERT_GT(b_conn->encrypted_packets_.size(), b_i);
 308     VLOG(1) << "Processing " << b_conn->encrypted_packets_.size() - b_i
 309             << " packets b->a";
 310     MovePackets(b_conn, &b_i, a, a_conn);
 311     if (callback_source) {
 312       callback_source->RunPendingCallbacks();
 313     }
 314   }
 315 }
 316
 317 // static
 318 pair<size_t, size_t> CryptoTestUtils::AdvanceHandshake(
 319     PacketSavingConnection* a_conn,
 320     QuicCryptoStream* a,
 321     size_t a_i,
 322     PacketSavingConnection* b_conn,
 323     QuicCryptoStream* b,
 324     size_t b_i) {
 325   VLOG(1) << "Processing " << a_conn->encrypted_packets_.size() - a_i
 326           << " packets a->b";
 327   MovePackets(a_conn, &a_i, b, b_conn);
 328
 329   VLOG(1) << "Processing " << b_conn->encrypted_packets_.size() - b_i
 330           << " packets b->a";
 331   if (b_conn->encrypted_packets_.size() - b_i == 2) {
 332     VLOG(1) << "here";
 333   }
 334   MovePackets(b_conn, &b_i, a, a_conn);
 335
 336   return std::make_pair(a_i, b_i);
 337 }
 338
 339 // static
 340 string CryptoTestUtils::GetValueForTag(const CryptoHandshakeMessage& message,
 341                                        QuicTag tag) {
 342   QuicTagValueMap::const_iterator it = message.tag_value_map().find(tag);
 343   if (it == message.tag_value_map().end()) {
 344     return string();
 345   }
 346   return it->second;
 347 }
 348
 349 class MockCommonCertSets : public CommonCertSets {
 350  public:
 351   MockCommonCertSets(StringPiece cert, uint64 hash, uint32 index)
 352       : cert_(cert.as_string()),
 353         hash_(hash),
 354         index_(index) {
 355   }
 356
 357   StringPiece GetCommonHashes() const override {
 358     CHECK(false) << "not implemented";
 359     return StringPiece();
 360   }
 361
 362   StringPiece GetCert(uint64 hash, uint32 index) const override {
 363     if (hash == hash_ && index == index_) {
 364       return cert_;
 365     }
 366     return StringPiece();
 367   }
 368
 369   bool MatchCert(StringPiece cert,
 370                  StringPiece common_set_hashes,
 371                  uint64* out_hash,
 372                  uint32* out_index) const override {
 373     if (cert != cert_) {
 374       return false;
 375     }
 376
 377     if (common_set_hashes.size() % sizeof(uint64) != 0) {
 378       return false;
 379     }
 380     bool client_has_set = false;
 381     for (size_t i = 0; i < common_set_hashes.size(); i += sizeof(uint64)) {
 382       uint64 hash;
 383       memcpy(&hash, common_set_hashes.data() + i, sizeof(hash));
 384       if (hash == hash_) {
 385         client_has_set = true;
 386         break;
 387       }
 388     }
 389
 390     if (!client_has_set) {
 391       return false;
 392     }
 393
 394     *out_hash = hash_;
 395     *out_index = index_;
 396     return true;
 397   }
 398
 399  private:
 400   const string cert_;
 401   const uint64 hash_;
 402   const uint32 index_;
 403 };
 404
 405 CommonCertSets* CryptoTestUtils::MockCommonCertSets(StringPiece cert,
 406                                                     uint64 hash,
 407                                                     uint32 index) {
 408   return new class MockCommonCertSets(cert, hash, index);
 409 }
 410
 411 void CryptoTestUtils::CompareClientAndServerKeys(
 412     QuicCryptoClientStream* client,
 413     QuicCryptoServerStream* server) {
 414   const QuicEncrypter* client_encrypter(
 415       client->session()->connection()->encrypter(ENCRYPTION_INITIAL));
 416   const QuicDecrypter* client_decrypter(
 417       client->session()->connection()->decrypter());
 418   const QuicEncrypter* client_forward_secure_encrypter(
 419       client->session()->connection()->encrypter(ENCRYPTION_FORWARD_SECURE));
 420   const QuicDecrypter* client_forward_secure_decrypter(
 421       client->session()->connection()->alternative_decrypter());
 422   const QuicEncrypter* server_encrypter(
 423       server->session()->connection()->encrypter(ENCRYPTION_INITIAL));
 424   const QuicDecrypter* server_decrypter(
 425       server->session()->connection()->decrypter());
 426   const QuicEncrypter* server_forward_secure_encrypter(
 427       server->session()->connection()->encrypter(ENCRYPTION_FORWARD_SECURE));
 428   const QuicDecrypter* server_forward_secure_decrypter(
 429       server->session()->connection()->alternative_decrypter());
 430
 431   StringPiece client_encrypter_key = client_encrypter->GetKey();
 432   StringPiece client_encrypter_iv = client_encrypter->GetNoncePrefix();
 433   StringPiece client_decrypter_key = client_decrypter->GetKey();
 434   StringPiece client_decrypter_iv = client_decrypter->GetNoncePrefix();
 435   StringPiece client_forward_secure_encrypter_key =
 436       client_forward_secure_encrypter->GetKey();
 437   StringPiece client_forward_secure_encrypter_iv =
 438       client_forward_secure_encrypter->GetNoncePrefix();
 439   StringPiece client_forward_secure_decrypter_key =
 440       client_forward_secure_decrypter->GetKey();
 441   StringPiece client_forward_secure_decrypter_iv =
 442       client_forward_secure_decrypter->GetNoncePrefix();
 443   StringPiece server_encrypter_key = server_encrypter->GetKey();
 444   StringPiece server_encrypter_iv = server_encrypter->GetNoncePrefix();
 445   StringPiece server_decrypter_key = server_decrypter->GetKey();
 446   StringPiece server_decrypter_iv = server_decrypter->GetNoncePrefix();
 447   StringPiece server_forward_secure_encrypter_key =
 448       server_forward_secure_encrypter->GetKey();
 449   StringPiece server_forward_secure_encrypter_iv =
 450       server_forward_secure_encrypter->GetNoncePrefix();
 451   StringPiece server_forward_secure_decrypter_key =
 452       server_forward_secure_decrypter->GetKey();
 453   StringPiece server_forward_secure_decrypter_iv =
 454       server_forward_secure_decrypter->GetNoncePrefix();
 455
 456   StringPiece client_subkey_secret =
 457       client->crypto_negotiated_params().subkey_secret;
 458   StringPiece server_subkey_secret =
 459       server->crypto_negotiated_params().subkey_secret;
 460
 461
 462   const char kSampleLabel[] = "label";
 463   const char kSampleContext[] = "context";
 464   const size_t kSampleOutputLength = 32;
 465   string client_key_extraction;
 466   string server_key_extraction;
 467   EXPECT_TRUE(client->ExportKeyingMaterial(kSampleLabel,
 468                                            kSampleContext,
 469                                            kSampleOutputLength,
 470                                            &client_key_extraction));
 471   EXPECT_TRUE(server->ExportKeyingMaterial(kSampleLabel,
 472                                            kSampleContext,
 473                                            kSampleOutputLength,
 474                                            &server_key_extraction));
 475
 476   CompareCharArraysWithHexError("client write key",
 477                                 client_encrypter_key.data(),
 478                                 client_encrypter_key.length(),
 479                                 server_decrypter_key.data(),
 480                                 server_decrypter_key.length());
 481   CompareCharArraysWithHexError("client write IV",
 482                                 client_encrypter_iv.data(),
 483                                 client_encrypter_iv.length(),
 484                                 server_decrypter_iv.data(),
 485                                 server_decrypter_iv.length());
 486   CompareCharArraysWithHexError("server write key",
 487                                 server_encrypter_key.data(),
 488                                 server_encrypter_key.length(),
 489                                 client_decrypter_key.data(),
 490                                 client_decrypter_key.length());
 491   CompareCharArraysWithHexError("server write IV",
 492                                 server_encrypter_iv.data(),
 493                                 server_encrypter_iv.length(),
 494                                 client_decrypter_iv.data(),
 495                                 client_decrypter_iv.length());
 496   CompareCharArraysWithHexError("client forward secure write key",
 497                                 client_forward_secure_encrypter_key.data(),
 498                                 client_forward_secure_encrypter_key.length(),
 499                                 server_forward_secure_decrypter_key.data(),
 500                                 server_forward_secure_decrypter_key.length());
 501   CompareCharArraysWithHexError("client forward secure write IV",
 502                                 client_forward_secure_encrypter_iv.data(),
 503                                 client_forward_secure_encrypter_iv.length(),
 504                                 server_forward_secure_decrypter_iv.data(),
 505                                 server_forward_secure_decrypter_iv.length());
 506   CompareCharArraysWithHexError("server forward secure write key",
 507                                 server_forward_secure_encrypter_key.data(),
 508                                 server_forward_secure_encrypter_key.length(),
 509                                 client_forward_secure_decrypter_key.data(),
 510                                 client_forward_secure_decrypter_key.length());
 511   CompareCharArraysWithHexError("server forward secure write IV",
 512                                 server_forward_secure_encrypter_iv.data(),
 513                                 server_forward_secure_encrypter_iv.length(),
 514                                 client_forward_secure_decrypter_iv.data(),
 515                                 client_forward_secure_decrypter_iv.length());
 516   CompareCharArraysWithHexError("subkey secret",
 517                                 client_subkey_secret.data(),
 518                                 client_subkey_secret.length(),
 519                                 server_subkey_secret.data(),
 520                                 server_subkey_secret.length());
 521   CompareCharArraysWithHexError("sample key extraction",
 522                                 client_key_extraction.data(),
 523                                 client_key_extraction.length(),
 524                                 server_key_extraction.data(),
 525                                 server_key_extraction.length());
 526 }
 527
 528 // static
 529 QuicTag CryptoTestUtils::ParseTag(const char* tagstr) {
 530   const size_t len = strlen(tagstr);
 531   CHECK_NE(0u, len);
 532
 533   QuicTag tag = 0;
 534
 535   if (tagstr[0] == '#') {
 536     CHECK_EQ(static_cast<size_t>(1 + 2*4), len);
 537     tagstr++;
 538
 539     for (size_t i = 0; i < 8; i++) {
 540       tag <<= 4;
 541
 542       uint8 v = 0;
 543       CHECK(HexChar(tagstr[i], &v));
 544       tag |= v;
 545     }
 546
 547     return tag;
 548   }
 549
 550   CHECK_LE(len, 4u);
 551   for (size_t i = 0; i < 4; i++) {
 552     tag >>= 8;
 553     if (i < len) {
 554       tag |= static_cast<uint32>(tagstr[i]) << 24;
 555     }
 556   }
 557
 558   return tag;
 559 }
 560
 561 // static
 562 CryptoHandshakeMessage CryptoTestUtils::Message(const char* message_tag, ...) {
 563   va_list ap;
 564   va_start(ap, message_tag);
 565
 566   CryptoHandshakeMessage message = BuildMessage(message_tag, ap);
 567   va_end(ap);
 568   return message;
 569 }
 570
 571 // static
 572 CryptoHandshakeMessage CryptoTestUtils::BuildMessage(const char* message_tag,
 573                                                      va_list ap) {
 574   CryptoHandshakeMessage msg;
 575   msg.set_tag(ParseTag(message_tag));
 576
 577   for (;;) {
 578     const char* tagstr = va_arg(ap, const char*);
 579     if (tagstr == nullptr) {
 580       break;
 581     }
 582
 583     if (tagstr[0] == '$') {
 584       // Special value.
 585       const char* const special = tagstr + 1;
 586       if (strcmp(special, "padding") == 0) {
 587         const int min_bytes = va_arg(ap, int);
 588         msg.set_minimum_size(min_bytes);
 589       } else {
 590         CHECK(false) << "Unknown special value: " << special;
 591       }
 592
 593       continue;
 594     }
 595
 596     const QuicTag tag = ParseTag(tagstr);
 597     const char* valuestr = va_arg(ap, const char*);
 598
 599     size_t len = strlen(valuestr);
 600     if (len > 0 && valuestr[0] == '#') {
 601       valuestr++;
 602       len--;
 603
 604       CHECK_EQ(0u, len % 2);
 605       scoped_ptr<uint8[]> buf(new uint8[len/2]);
 606
 607       for (size_t i = 0; i < len/2; i++) {
 608         uint8 v = 0;
 609         CHECK(HexChar(valuestr[i*2], &v));
 610         buf[i] = v << 4;
 611         CHECK(HexChar(valuestr[i*2 + 1], &v));
 612         buf[i] |= v;
 613       }
 614
 615       msg.SetStringPiece(
 616           tag, StringPiece(reinterpret_cast<char*>(buf.get()), len/2));
 617       continue;
 618     }
 619
 620     msg.SetStringPiece(tag, valuestr);
 621   }
 622
 623   // The CryptoHandshakeMessage needs to be serialized and parsed to ensure
 624   // that any padding is included.
 625   scoped_ptr<QuicData> bytes(CryptoFramer::ConstructHandshakeMessage(msg));
 626   scoped_ptr<CryptoHandshakeMessage> parsed(
 627       CryptoFramer::ParseMessage(bytes->AsStringPiece()));
 628   CHECK(parsed.get());
 629
 630   return *parsed;
 631 }
 632
 633 }  // namespace test
 634 }  // namespace net