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_framer_peer.h"
  21 #include "net/quic/test_tools/quic_test_utils.h"
  22 #include "net/quic/test_tools/simple_quic_framer.h"
  23
  24 using base::StringPiece;
  25 using std::make_pair;
  26 using std::pair;
  27 using std::string;
  28 using std::vector;
  29
  30 namespace net {
  31 namespace test {
  32
  33 namespace {
  34
  35 const char kServerHostname[] = "test.example.com";
  36 const uint16 kServerPort = 80;
  37
  38 // CryptoFramerVisitor is a framer visitor that records handshake messages.
  39 class CryptoFramerVisitor : public CryptoFramerVisitorInterface {
  40  public:
  41   CryptoFramerVisitor()
  42       : error_(false) {
  43   }
  44
  45   void OnError(CryptoFramer* framer) override { error_ = true; }
  46
  47   void OnHandshakeMessage(const CryptoHandshakeMessage& message) override {
  48     messages_.push_back(message);
  49   }
  50
  51   bool error() const {
  52     return error_;
  53   }
  54
  55   const vector<CryptoHandshakeMessage>& messages() const {
  56     return messages_;
  57   }
  58
  59  private:
  60   bool error_;
  61   vector<CryptoHandshakeMessage> messages_;
  62 };
  63
  64 // MovePackets parses crypto handshake messages from packet number
  65 // |*inout_packet_index| through to the last packet (or until a packet fails to
  66 // decrypt) and has |dest_stream| process them. |*inout_packet_index| is updated
  67 // with an index one greater than the last packet processed.
  68 void MovePackets(PacketSavingConnection* source_conn,
  69                  size_t *inout_packet_index,
  70                  QuicCryptoStream* dest_stream,
  71                  PacketSavingConnection* dest_conn) {
  72   SimpleQuicFramer framer(source_conn->supported_versions());
  73   CryptoFramer crypto_framer;
  74   CryptoFramerVisitor crypto_visitor;
  75
  76   // In order to properly test the code we need to perform encryption and
  77   // decryption so that the crypters latch when expected. The crypters are in
  78   // |dest_conn|, but we don't want to try and use them there. Instead we swap
  79   // them into |framer|, perform the decryption with them, and then swap them
  80   // back.
  81   QuicConnectionPeer::SwapCrypters(dest_conn, framer.framer());
  82
  83   crypto_framer.set_visitor(&crypto_visitor);
  84
  85   size_t index = *inout_packet_index;
  86   for (; index < source_conn->encrypted_packets_.size(); index++) {
  87     if (!framer.ProcessPacket(*source_conn->encrypted_packets_[index])) {
  88       // The framer will be unable to decrypt forward-secure packets sent after
  89       // the handshake is complete. Don't treat them as handshake packets.
  90       break;
  91     }
  92
  93     for (const QuicStreamFrame& stream_frame : framer.stream_frames()) {
  94       ASSERT_TRUE(crypto_framer.ProcessInput(stream_frame.data));
  95       ASSERT_FALSE(crypto_visitor.error());
  96     }
  97   }
  98   *inout_packet_index = index;
  99
 100   QuicConnectionPeer::SwapCrypters(dest_conn, framer.framer());
 101
 102   ASSERT_EQ(0u, crypto_framer.InputBytesRemaining());
 103
 104   for (const CryptoHandshakeMessage& message : crypto_visitor.messages()) {
 105     dest_stream->OnHandshakeMessage(message);
 106   }
 107 }
 108
 109 // HexChar parses |c| as a hex character. If valid, it sets |*value| to the
 110 // value of the hex character and returns true. Otherwise it returns false.
 111 bool HexChar(char c, uint8* value) {
 112   if (c >= '0' && c <= '9') {
 113     *value = c - '0';
 114     return true;
 115   }
 116   if (c >= 'a' && c <= 'f') {
 117     *value = c - 'a' + 10;
 118     return true;
 119   }
 120   if (c >= 'A' && c <= 'F') {
 121     *value = c - 'A' + 10;
 122     return true;
 123   }
 124   return false;
 125 }
 126
 127 // A ChannelIDSource that works in asynchronous mode unless the |callback|
 128 // argument to GetChannelIDKey is nullptr.
 129 class AsyncTestChannelIDSource : public ChannelIDSource,
 130                                  public CryptoTestUtils::CallbackSource {
 131  public:
 132   // Takes ownership of |sync_source|, a synchronous ChannelIDSource.
 133   explicit AsyncTestChannelIDSource(ChannelIDSource* sync_source)
 134       : sync_source_(sync_source) {}
 135   ~AsyncTestChannelIDSource() override {}
 136
 137   // ChannelIDSource implementation.
 138   QuicAsyncStatus GetChannelIDKey(const string& hostname,
 139                                   scoped_ptr<ChannelIDKey>* channel_id_key,
 140                                   ChannelIDSourceCallback* callback) override {
 141     // Synchronous mode.
 142     if (!callback) {
 143       return sync_source_->GetChannelIDKey(hostname, channel_id_key, nullptr);
 144     }
 145
 146     // Asynchronous mode.
 147     QuicAsyncStatus status =
 148         sync_source_->GetChannelIDKey(hostname, &channel_id_key_, nullptr);
 149     if (status != QUIC_SUCCESS) {
 150       return QUIC_FAILURE;
 151     }
 152     callback_.reset(callback);
 153     return QUIC_PENDING;
 154   }
 155
 156   // CallbackSource implementation.
 157   void RunPendingCallbacks() override {
 158     if (callback_.get()) {
 159       callback_->Run(&channel_id_key_);
 160       callback_.reset();
 161     }
 162   }
 163
 164  private:
 165   scoped_ptr<ChannelIDSource> sync_source_;
 166   scoped_ptr<ChannelIDSourceCallback> callback_;
 167   scoped_ptr<ChannelIDKey> channel_id_key_;
 168 };
 169
 170 }  // anonymous namespace
 171
 172 CryptoTestUtils::FakeClientOptions::FakeClientOptions()
 173     : dont_verify_certs(false),
 174       channel_id_enabled(false),
 175       channel_id_source_async(false) {
 176 }
 177
 178 // static
 179 int CryptoTestUtils::HandshakeWithFakeServer(
 180     PacketSavingConnection* client_conn,
 181     QuicCryptoClientStream* client) {
 182   PacketSavingConnection* server_conn = new PacketSavingConnection(
 183       Perspective::IS_SERVER, client_conn->supported_versions());
 184
 185   QuicConfig config = DefaultQuicConfig();
 186   QuicCryptoServerConfig crypto_config(QuicCryptoServerConfig::TESTING,
 187                                        QuicRandom::GetInstance());
 188   SetupCryptoServerConfigForTest(server_conn->clock(),
 189                                  server_conn->random_generator(), &config,
 190                                  &crypto_config);
 191
 192   TestQuicSpdyServerSession server_session(server_conn, config, &crypto_config);
 193
 194   // The client's handshake must have been started already.
 195   CHECK_NE(0u, client_conn->encrypted_packets_.size());
 196
 197   CommunicateHandshakeMessages(client_conn, client, server_conn,
 198                                server_session.GetCryptoStream());
 199
 200   CompareClientAndServerKeys(client, server_session.GetCryptoStream());
 201
 202   return client->num_sent_client_hellos();
 203 }
 204
 205 // static
 206 int CryptoTestUtils::HandshakeWithFakeClient(
 207     PacketSavingConnection* server_conn,
 208     QuicCryptoServerStream* server,
 209     const FakeClientOptions& options) {
 210   PacketSavingConnection* client_conn =
 211       new PacketSavingConnection(Perspective::IS_CLIENT);
 212   // Advance the time, because timers do not like uninitialized times.
 213   client_conn->AdvanceTime(QuicTime::Delta::FromSeconds(1));
 214
 215   QuicCryptoClientConfig crypto_config;
 216   bool is_https = false;
 217   AsyncTestChannelIDSource* async_channel_id_source = nullptr;
 218   if (options.channel_id_enabled) {
 219     is_https = true;
 220
 221     ChannelIDSource* source = ChannelIDSourceForTesting();
 222     if (options.channel_id_source_async) {
 223       async_channel_id_source = new AsyncTestChannelIDSource(source);
 224       source = async_channel_id_source;
 225     }
 226     crypto_config.SetChannelIDSource(source);
 227   }
 228   QuicServerId server_id(kServerHostname, kServerPort, is_https,
 229                          PRIVACY_MODE_DISABLED);
 230   if (!options.dont_verify_certs) {
 231 #if defined(USE_OPENSSL)
 232     crypto_config.SetProofVerifier(ProofVerifierForTesting());
 233 #else
 234     // TODO(rch): Implement a NSS proof source.
 235     crypto_config.SetProofVerifier(FakeProofVerifierForTesting());
 236 #endif
 237   }
 238   TestQuicSpdyClientSession client_session(client_conn, DefaultQuicConfig(),
 239                                            server_id, &crypto_config);
 240
 241   client_session.GetCryptoStream()->CryptoConnect();
 242   CHECK_EQ(1u, client_conn->encrypted_packets_.size());
 243
 244   CommunicateHandshakeMessagesAndRunCallbacks(
 245       client_conn, client_session.GetCryptoStream(), server_conn, server,
 246       async_channel_id_source);
 247
 248   CompareClientAndServerKeys(client_session.GetCryptoStream(), server);
 249
 250   if (options.channel_id_enabled) {
 251     scoped_ptr<ChannelIDKey> channel_id_key;
 252     QuicAsyncStatus status = crypto_config.channel_id_source()->GetChannelIDKey(
 253         kServerHostname, &channel_id_key, nullptr);
 254     EXPECT_EQ(QUIC_SUCCESS, status);
 255     EXPECT_EQ(channel_id_key->SerializeKey(),
 256               server->crypto_negotiated_params().channel_id);
 257     EXPECT_EQ(
 258         options.channel_id_source_async,
 259         client_session.GetCryptoStream()->WasChannelIDSourceCallbackRun());
 260   }
 261
 262   return client_session.GetCryptoStream()->num_sent_client_hellos();
 263 }
 264
 265 // static
 266 void CryptoTestUtils::SetupCryptoServerConfigForTest(
 267     const QuicClock* clock,
 268     QuicRandom* rand,
 269     QuicConfig* config,
 270     QuicCryptoServerConfig* crypto_config) {
 271   QuicCryptoServerConfig::ConfigOptions options;
 272   options.channel_id_enabled = true;
 273   scoped_ptr<CryptoHandshakeMessage> scfg(
 274       crypto_config->AddDefaultConfig(rand, clock, options));
 275 }
 276
 277 // static
 278 void CryptoTestUtils::CommunicateHandshakeMessages(
 279     PacketSavingConnection* a_conn,
 280     QuicCryptoStream* a,
 281     PacketSavingConnection* b_conn,
 282     QuicCryptoStream* b) {
 283   CommunicateHandshakeMessagesAndRunCallbacks(a_conn, a, b_conn, b, nullptr);
 284 }
 285
 286 // static
 287 void CryptoTestUtils::CommunicateHandshakeMessagesAndRunCallbacks(
 288     PacketSavingConnection* a_conn,
 289     QuicCryptoStream* a,
 290     PacketSavingConnection* b_conn,
 291     QuicCryptoStream* b,
 292     CallbackSource* callback_source) {
 293   size_t a_i = 0, b_i = 0;
 294   while (!a->handshake_confirmed()) {
 295     ASSERT_GT(a_conn->encrypted_packets_.size(), a_i);
 296     VLOG(1) << "Processing " << a_conn->encrypted_packets_.size() - a_i
 297             << " packets a->b";
 298     MovePackets(a_conn, &a_i, b, b_conn);
 299     if (callback_source) {
 300       callback_source->RunPendingCallbacks();
 301     }
 302
 303     ASSERT_GT(b_conn->encrypted_packets_.size(), b_i);
 304     VLOG(1) << "Processing " << b_conn->encrypted_packets_.size() - b_i
 305             << " packets b->a";
 306     MovePackets(b_conn, &b_i, a, a_conn);
 307     if (callback_source) {
 308       callback_source->RunPendingCallbacks();
 309     }
 310   }
 311 }
 312
 313 // static
 314 pair<size_t, size_t> CryptoTestUtils::AdvanceHandshake(
 315     PacketSavingConnection* a_conn,
 316     QuicCryptoStream* a,
 317     size_t a_i,
 318     PacketSavingConnection* b_conn,
 319     QuicCryptoStream* b,
 320     size_t b_i) {
 321   VLOG(1) << "Processing " << a_conn->encrypted_packets_.size() - a_i
 322           << " packets a->b";
 323   MovePackets(a_conn, &a_i, b, b_conn);
 324
 325   VLOG(1) << "Processing " << b_conn->encrypted_packets_.size() - b_i
 326           << " packets b->a";
 327   if (b_conn->encrypted_packets_.size() - b_i == 2) {
 328     VLOG(1) << "here";
 329   }
 330   MovePackets(b_conn, &b_i, a, a_conn);
 331
 332   return std::make_pair(a_i, b_i);
 333 }
 334
 335 // static
 336 string CryptoTestUtils::GetValueForTag(const CryptoHandshakeMessage& message,
 337                                        QuicTag tag) {
 338   QuicTagValueMap::const_iterator it = message.tag_value_map().find(tag);
 339   if (it == message.tag_value_map().end()) {
 340     return string();
 341   }
 342   return it->second;
 343 }
 344
 345 class MockCommonCertSets : public CommonCertSets {
 346  public:
 347   MockCommonCertSets(StringPiece cert, uint64 hash, uint32 index)
 348       : cert_(cert.as_string()),
 349         hash_(hash),
 350         index_(index) {
 351   }
 352
 353   StringPiece GetCommonHashes() const override {
 354     CHECK(false) << "not implemented";
 355     return StringPiece();
 356   }
 357
 358   StringPiece GetCert(uint64 hash, uint32 index) const override {
 359     if (hash == hash_ && index == index_) {
 360       return cert_;
 361     }
 362     return StringPiece();
 363   }
 364
 365   bool MatchCert(StringPiece cert,
 366                  StringPiece common_set_hashes,
 367                  uint64* out_hash,
 368                  uint32* out_index) const override {
 369     if (cert != cert_) {
 370       return false;
 371     }
 372
 373     if (common_set_hashes.size() % sizeof(uint64) != 0) {
 374       return false;
 375     }
 376     bool client_has_set = false;
 377     for (size_t i = 0; i < common_set_hashes.size(); i += sizeof(uint64)) {
 378       uint64 hash;
 379       memcpy(&hash, common_set_hashes.data() + i, sizeof(hash));
 380       if (hash == hash_) {
 381         client_has_set = true;
 382         break;
 383       }
 384     }
 385
 386     if (!client_has_set) {
 387       return false;
 388     }
 389
 390     *out_hash = hash_;
 391     *out_index = index_;
 392     return true;
 393   }
 394
 395  private:
 396   const string cert_;
 397   const uint64 hash_;
 398   const uint32 index_;
 399 };
 400
 401 CommonCertSets* CryptoTestUtils::MockCommonCertSets(StringPiece cert,
 402                                                     uint64 hash,
 403                                                     uint32 index) {
 404   return new class MockCommonCertSets(cert, hash, index);
 405 }
 406
 407 void CryptoTestUtils::CompareClientAndServerKeys(
 408     QuicCryptoClientStream* client,
 409     QuicCryptoServerStream* server) {
 410   QuicFramer* client_framer =
 411       QuicConnectionPeer::GetFramer(client->session()->connection());
 412   QuicFramer* server_framer =
 413       QuicConnectionPeer::GetFramer(server->session()->connection());
 414   const QuicEncrypter* client_encrypter(
 415       QuicFramerPeer::GetEncrypter(client_framer, ENCRYPTION_INITIAL));
 416   const QuicDecrypter* client_decrypter(
 417       client->session()->connection()->decrypter());
 418   const QuicEncrypter* client_forward_secure_encrypter(
 419       QuicFramerPeer::GetEncrypter(client_framer, ENCRYPTION_FORWARD_SECURE));
 420   const QuicDecrypter* client_forward_secure_decrypter(
 421       client->session()->connection()->alternative_decrypter());
 422   const QuicEncrypter* server_encrypter(
 423       QuicFramerPeer::GetEncrypter(server_framer, ENCRYPTION_INITIAL));
 424   const QuicDecrypter* server_decrypter(
 425       server->session()->connection()->decrypter());
 426   const QuicEncrypter* server_forward_secure_encrypter(
 427       QuicFramerPeer::GetEncrypter(server_framer, 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 msg;
 567   msg.set_tag(ParseTag(message_tag));
 568
 569   for (;;) {
 570     const char* tagstr = va_arg(ap, const char*);
 571     if (tagstr == nullptr) {
 572       break;
 573     }
 574
 575     if (tagstr[0] == '$') {
 576       // Special value.
 577       const char* const special = tagstr + 1;
 578       if (strcmp(special, "padding") == 0) {
 579         const int min_bytes = va_arg(ap, int);
 580         msg.set_minimum_size(min_bytes);
 581       } else {
 582         CHECK(false) << "Unknown special value: " << special;
 583       }
 584
 585       continue;
 586     }
 587
 588     const QuicTag tag = ParseTag(tagstr);
 589     const char* valuestr = va_arg(ap, const char*);
 590
 591     size_t len = strlen(valuestr);
 592     if (len > 0 && valuestr[0] == '#') {
 593       valuestr++;
 594       len--;
 595
 596       CHECK_EQ(0u, len % 2);
 597       scoped_ptr<uint8[]> buf(new uint8[len/2]);
 598
 599       for (size_t i = 0; i < len/2; i++) {
 600         uint8 v = 0;
 601         CHECK(HexChar(valuestr[i*2], &v));
 602         buf[i] = v << 4;
 603         CHECK(HexChar(valuestr[i*2 + 1], &v));
 604         buf[i] |= v;
 605       }
 606
 607       msg.SetStringPiece(
 608           tag, StringPiece(reinterpret_cast<char*>(buf.get()), len/2));
 609       continue;
 610     }
 611
 612     msg.SetStringPiece(tag, valuestr);
 613   }
 614
 615   // The CryptoHandshakeMessage needs to be serialized and parsed to ensure
 616   // that any padding is included.
 617   scoped_ptr<QuicData> bytes(CryptoFramer::ConstructHandshakeMessage(msg));
 618   scoped_ptr<CryptoHandshakeMessage> parsed(
 619       CryptoFramer::ParseMessage(bytes->AsStringPiece()));
 620   CHECK(parsed.get());
 621
 622   va_end(ap);
 623   return *parsed;
 624 }
 625
 626 }  // namespace test
 627 }  // namespace net