text: // Copyright (c) 2012 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.
  
  #include "net/socket/ssl_client_socket_impl.h"
  
  #include <errno.h>
  #include <string.h>
  
  #include <utility>
  
  #include "base/bind.h"
  #include "base/callback_helpers.h"
  #include "base/feature_list.h"
  #include "base/lazy_instance.h"
  #include "base/macros.h"
  #include "base/memory/singleton.h"
  #include "base/metrics/field_trial.h"
  #include "base/metrics/histogram_macros.h"
  #include "base/metrics/sparse_histogram.h"
  #include "base/profiler/scoped_tracker.h"
  #include "base/strings/string_number_conversions.h"
  #include "base/strings/string_piece.h"
  #include "base/synchronization/lock.h"
  #include "base/threading/thread_local.h"
  #include "base/trace_event/trace_event.h"
  #include "base/values.h"
  #include "crypto/ec_private_key.h"
  #include "crypto/openssl_util.h"
  #include "net/base/ip_address.h"
  #include "net/base/net_errors.h"
  #include "net/cert/cert_verifier.h"
  #include "net/cert/ct_ev_whitelist.h"
  #include "net/cert/ct_policy_enforcer.h"
  #include "net/cert/ct_policy_status.h"
  #include "net/cert/ct_verifier.h"
  #include "net/cert/x509_certificate_net_log_param.h"
  #include "net/cert/x509_util_openssl.h"
  #include "net/http/transport_security_state.h"
  #include "net/log/net_log.h"
  #include "net/log/net_log_event_type.h"
  #include "net/log/net_log_parameters_callback.h"
  #include "net/ssl/ssl_cert_request_info.h"
  #include "net/ssl/ssl_cipher_suite_names.h"
  #include "net/ssl/ssl_client_session_cache.h"
  #include "net/ssl/ssl_connection_status_flags.h"
  #include "net/ssl/ssl_info.h"
  #include "net/ssl/ssl_private_key.h"
  #include "net/ssl/token_binding.h"
  #include "third_party/boringssl/src/include/openssl/bio.h"
  #include "third_party/boringssl/src/include/openssl/bytestring.h"
  #include "third_party/boringssl/src/include/openssl/err.h"
  #include "third_party/boringssl/src/include/openssl/evp.h"
  #include "third_party/boringssl/src/include/openssl/mem.h"
  #include "third_party/boringssl/src/include/openssl/ssl.h"
  
  #if !defined(OS_NACL)
  #include "net/ssl/ssl_key_logger.h"
  #endif
  
  #if defined(USE_NSS_CERTS)
  #include "net/cert_net/nss_ocsp.h"
  #endif
  
  namespace net {
  
  namespace {
  
  // This constant can be any non-negative/non-zero value (eg: it does not
  // overlap with any value of the net::Error range, including net::OK).
  const int kNoPendingResult = 1;
  
  // Default size of the internal BoringSSL buffers.
  const int kDefaultOpenSSLBufferSize = 17 * 1024;
  
  // TLS extension number use for Token Binding.
  const unsigned int kTbExtNum = 24;
  
  // Token Binding ProtocolVersions supported.
  const uint8_t kTbProtocolVersionMajor = 0;
  const uint8_t kTbProtocolVersionMinor = 10;
  const uint8_t kTbMinProtocolVersionMajor = 0;
  const uint8_t kTbMinProtocolVersionMinor = 10;
  
  bool EVP_MDToPrivateKeyHash(const EVP_MD* md, SSLPrivateKey::Hash* hash) {
    switch (EVP_MD_type(md)) {
      case NID_md5_sha1:
        *hash = SSLPrivateKey::Hash::MD5_SHA1;
        return true;
      case NID_sha1:
        *hash = SSLPrivateKey::Hash::SHA1;
        return true;
      case NID_sha256:
        *hash = SSLPrivateKey::Hash::SHA256;
        return true;
      case NID_sha384:
        *hash = SSLPrivateKey::Hash::SHA384;
        return true;
      case NID_sha512:
        *hash = SSLPrivateKey::Hash::SHA512;
        return true;
      default:
        return false;
    }
  }
  
  std::unique_ptr<base::Value> NetLogPrivateKeyOperationCallback(
      SSLPrivateKey::Type type,
      SSLPrivateKey::Hash hash,
      NetLogCaptureMode mode) {
    std::string type_str;
    switch (type) {
      case SSLPrivateKey::Type::RSA:
        type_str = "RSA";
        break;
      case SSLPrivateKey::Type::ECDSA_P256:
        type_str = "ECDSA_P256";
        break;
      case SSLPrivateKey::Type::ECDSA_P384:
        type_str = "ECDSA_P384";
        break;
      case SSLPrivateKey::Type::ECDSA_P521:
        type_str = "ECDSA_P521";
        break;
    }
  
    std::string hash_str;
    switch (hash) {
      case SSLPrivateKey::Hash::MD5_SHA1:
        hash_str = "MD5_SHA1";
        break;
      case SSLPrivateKey::Hash::SHA1:
        hash_str = "SHA1";
        break;
      case SSLPrivateKey::Hash::SHA256:
        hash_str = "SHA256";
        break;
      case SSLPrivateKey::Hash::SHA384:
        hash_str = "SHA384";
        break;
      case SSLPrivateKey::Hash::SHA512:
        hash_str = "SHA512";
        break;
    }
  
    std::unique_ptr<base::DictionaryValue> value(new base::DictionaryValue);
    value->SetString("type", type_str);
    value->SetString("hash", hash_str);
    return std::move(value);
  }
  
  std::unique_ptr<base::Value> NetLogChannelIDLookupCallback(
      ChannelIDService* channel_id_service,
      NetLogCaptureMode capture_mode) {
    ChannelIDStore* store = channel_id_service->GetChannelIDStore();
    std::unique_ptr<base::DictionaryValue> dict(new base::DictionaryValue());
    dict->SetBoolean("ephemeral", store->IsEphemeral());
    dict->SetString("service", base::HexEncode(&channel_id_service,
                                               sizeof(channel_id_service)));
    dict->SetString("store", base::HexEncode(&store, sizeof(store)));
    return std::move(dict);
  }
  
  std::unique_ptr<base::Value> NetLogChannelIDLookupCompleteCallback(
      crypto::ECPrivateKey* key,
      int result,
      NetLogCaptureMode capture_mode) {
    std::unique_ptr<base::DictionaryValue> dict(new base::DictionaryValue());
    dict->SetInteger("net_error", result);
    std::string raw_key;
    if (result == OK && key && key->ExportRawPublicKey(&raw_key)) {
      std::string key_to_log = "redacted";
      if (capture_mode.include_cookies_and_credentials()) {
        key_to_log = base::HexEncode(raw_key.data(), raw_key.length());
      }
      dict->SetString("key", key_to_log);
    }
    return std::move(dict);
  }
  
  std::unique_ptr<base::Value> NetLogSSLInfoCallback(
      SSLClientSocketImpl* socket,
      NetLogCaptureMode capture_mode) {
    SSLInfo ssl_info;
    if (!socket->GetSSLInfo(&ssl_info))
      return nullptr;
  
    std::unique_ptr<base::DictionaryValue> dict(new base::DictionaryValue());
    const char* version_str;
    SSLVersionToString(&version_str,
                       SSLConnectionStatusToVersion(ssl_info.connection_status));
    dict->SetString("version", version_str);
    dict->SetBoolean("is_resumed",
                     ssl_info.handshake_type == SSLInfo::HANDSHAKE_RESUME);
    dict->SetInteger("cipher_suite", SSLConnectionStatusToCipherSuite(
                                         ssl_info.connection_status));
  
    dict->SetString("next_proto",
                    NextProtoToString(socket->GetNegotiatedProtocol()));
  
    return std::move(dict);
  }
  
  int GetBufferSize(const char* field_trial) {
    // Get buffer sizes from field trials, if possible. If values not present,
    // use default.  Also make sure values are in reasonable range.
    int buffer_size = kDefaultOpenSSLBufferSize;
  #if !defined(OS_NACL)
    int override_buffer_size;
    if (base::StringToInt(base::FieldTrialList::FindFullName(field_trial),
                          &override_buffer_size)) {
      buffer_size = override_buffer_size;
      buffer_size = std::max(buffer_size, 1000);
      buffer_size = std::min(buffer_size, 2 * kDefaultOpenSSLBufferSize);
    }
  #endif  // !defined(OS_NACL)
    return buffer_size;
  }
  
  #if defined(OS_NACL)
  bool AreLegacyECDSACiphersEnabled() {
    return false;
  }
  #else
  // TODO(davidben): Remove this after the ECDSA CBC removal sticks.
  // https:/crbug.com/666191.
  const base::Feature kLegacyECDSACiphersFeature{
      "SSLLegacyECDSACiphers", base::FEATURE_DISABLED_BY_DEFAULT};
  
  bool AreLegacyECDSACiphersEnabled() {
    return base::FeatureList::IsEnabled(kLegacyECDSACiphersFeature);
  }
  #endif
  
  }  // namespace
  
  class SSLClientSocketImpl::SSLContext {
   public:
    static SSLContext* GetInstance() {
      return base::Singleton<SSLContext>::get();
    }
    SSL_CTX* ssl_ctx() { return ssl_ctx_.get(); }
    SSLClientSessionCache* session_cache() { return &session_cache_; }
  
    SSLClientSocketImpl* GetClientSocketFromSSL(const SSL* ssl) {
      DCHECK(ssl);
      SSLClientSocketImpl* socket = static_cast<SSLClientSocketImpl*>(
          SSL_get_ex_data(ssl, ssl_socket_data_index_));
      DCHECK(socket);
      return socket;
    }
  
    bool SetClientSocketForSSL(SSL* ssl, SSLClientSocketImpl* socket) {
      return SSL_set_ex_data(ssl, ssl_socket_data_index_, socket) != 0;
    }
  
  #if !defined(OS_NACL)
    void SetSSLKeyLogFile(
        const base::FilePath& path,
        const scoped_refptr<base::SequencedTaskRunner>& task_runner) {
      DCHECK(!ssl_key_logger_);
      ssl_key_logger_.reset(new SSLKeyLogger(path, task_runner));
      SSL_CTX_set_keylog_callback(ssl_ctx_.get(), KeyLogCallback);
    }
  #endif
  
    static const SSL_PRIVATE_KEY_METHOD kPrivateKeyMethod;
  
   private:
    friend struct base::DefaultSingletonTraits<SSLContext>;
  
    SSLContext() : session_cache_(SSLClientSessionCache::Config()) {
      crypto::EnsureOpenSSLInit();
      ssl_socket_data_index_ = SSL_get_ex_new_index(0, 0, 0, 0, 0);
      DCHECK_NE(ssl_socket_data_index_, -1);
      ssl_ctx_.reset(SSL_CTX_new(SSLv23_client_method()));
      SSL_CTX_set_cert_verify_callback(ssl_ctx_.get(), CertVerifyCallback, NULL);
      SSL_CTX_set_cert_cb(ssl_ctx_.get(), ClientCertRequestCallback, NULL);
      SSL_CTX_set_verify(ssl_ctx_.get(), SSL_VERIFY_PEER, NULL);
  
      // Disable the internal session cache. Session caching is handled
      // externally (i.e. by SSLClientSessionCache).
      SSL_CTX_set_session_cache_mode(
          ssl_ctx_.get(), SSL_SESS_CACHE_CLIENT | SSL_SESS_CACHE_NO_INTERNAL);
      SSL_CTX_sess_set_new_cb(ssl_ctx_.get(), NewSessionCallback);
      SSL_CTX_set_timeout(ssl_ctx_.get(), 1 * 60 * 60 /* one hour */);
  
      SSL_CTX_set_grease_enabled(ssl_ctx_.get(), 1);
  
      if (!SSL_CTX_add_client_custom_ext(ssl_ctx_.get(), kTbExtNum,
                                         &TokenBindingAddCallback,
                                         &TokenBindingFreeCallback, nullptr,
                                         &TokenBindingParseCallback, nullptr)) {
        NOTREACHED();
      }
    }
  
    static int TokenBindingAddCallback(SSL* ssl,
                                       unsigned int extension_value,
                                       const uint8_t** out,
                                       size_t* out_len,
                                       int* out_alert_value,
                                       void* add_arg) {
      DCHECK_EQ(extension_value, kTbExtNum);
      SSLClientSocketImpl* socket =
          SSLClientSocketImpl::SSLContext::GetInstance()->GetClientSocketFromSSL(
              ssl);
      return socket->TokenBindingAdd(out, out_len, out_alert_value);
    }
  
    static void TokenBindingFreeCallback(SSL* ssl,
                                         unsigned extension_value,
                                         const uint8_t* out,
                                         void* add_arg) {
      DCHECK_EQ(extension_value, kTbExtNum);
      OPENSSL_free(const_cast<unsigned char*>(out));
    }
  
    static int TokenBindingParseCallback(SSL* ssl,
                                         unsigned int extension_value,
                                         const uint8_t* contents,
                                         size_t contents_len,
                                         int* out_alert_value,
                                         void* parse_arg) {
      DCHECK_EQ(extension_value, kTbExtNum);
      SSLClientSocketImpl* socket =
          SSLClientSocketImpl::SSLContext::GetInstance()->GetClientSocketFromSSL(
              ssl);
      return socket->TokenBindingParse(contents, contents_len, out_alert_value);
    }
  
    static int ClientCertRequestCallback(SSL* ssl, void* arg) {
      SSLClientSocketImpl* socket = GetInstance()->GetClientSocketFromSSL(ssl);
      DCHECK(socket);
      return socket->ClientCertRequestCallback(ssl);
    }
  
    static int CertVerifyCallback(X509_STORE_CTX* store_ctx, void* arg) {
      SSL* ssl = reinterpret_cast<SSL*>(X509_STORE_CTX_get_ex_data(
          store_ctx, SSL_get_ex_data_X509_STORE_CTX_idx()));
      SSLClientSocketImpl* socket = GetInstance()->GetClientSocketFromSSL(ssl);
      CHECK(socket);
  
      return socket->CertVerifyCallback(store_ctx);
    }
  
    static int NewSessionCallback(SSL* ssl, SSL_SESSION* session) {
      SSLClientSocketImpl* socket = GetInstance()->GetClientSocketFromSSL(ssl);
      return socket->NewSessionCallback(session);
    }
  
    static int PrivateKeyTypeCallback(SSL* ssl) {
      SSLClientSocketImpl* socket = GetInstance()->GetClientSocketFromSSL(ssl);
      return socket->PrivateKeyTypeCallback();
    }
  
    static size_t PrivateKeyMaxSignatureLenCallback(SSL* ssl) {
      SSLClientSocketImpl* socket = GetInstance()->GetClientSocketFromSSL(ssl);
      return socket->PrivateKeyMaxSignatureLenCallback();
    }
  
    static ssl_private_key_result_t PrivateKeySignDigestCallback(
        SSL* ssl,
        uint8_t* out,
        size_t* out_len,
        size_t max_out,
        const EVP_MD* md,
        const uint8_t* in,
        size_t in_len) {
      SSLClientSocketImpl* socket = GetInstance()->GetClientSocketFromSSL(ssl);
      return socket->PrivateKeySignDigestCallback(out, out_len, max_out, md, in,
                                                  in_len);
    }
  
    static ssl_private_key_result_t PrivateKeyCompleteCallback(SSL* ssl,
                                                               uint8_t* out,
                                                               size_t* out_len,
                                                               size_t max_out) {
      SSLClientSocketImpl* socket = GetInstance()->GetClientSocketFromSSL(ssl);
      return socket->PrivateKeyCompleteCallback(out, out_len, max_out);
    }
  
  #if !defined(OS_NACL)
    static void KeyLogCallback(const SSL* ssl, const char* line) {
      GetInstance()->ssl_key_logger_->WriteLine(line);
    }
  #endif
  
    // This is the index used with SSL_get_ex_data to retrieve the owner
    // SSLClientSocketImpl object from an SSL instance.
    int ssl_socket_data_index_;
  
    bssl::UniquePtr<SSL_CTX> ssl_ctx_;
  
  #if !defined(OS_NACL)
    std::unique_ptr<SSLKeyLogger> ssl_key_logger_;
  #endif
  
    // TODO(davidben): Use a separate cache per URLRequestContext.
    // https://crbug.com/458365
    //
    // TODO(davidben): Sessions should be invalidated on fatal
    // alerts. https://crbug.com/466352
    SSLClientSessionCache session_cache_;
  };
  
  // TODO(davidben): Switch from sign_digest to sign.
  const SSL_PRIVATE_KEY_METHOD
      SSLClientSocketImpl::SSLContext::kPrivateKeyMethod = {
          &SSLClientSocketImpl::SSLContext::PrivateKeyTypeCallback,
          &SSLClientSocketImpl::SSLContext::PrivateKeyMaxSignatureLenCallback,
          nullptr /* sign */,
          &SSLClientSocketImpl::SSLContext::PrivateKeySignDigestCallback,
          nullptr /* decrypt */,
          &SSLClientSocketImpl::SSLContext::PrivateKeyCompleteCallback,
  };
  
  // PeerCertificateChain is a helper object which extracts the certificate
  // chain, as given by the server, from an OpenSSL socket and performs the needed
  // resource management. The first element of the chain is the leaf certificate
  // and the other elements are in the order given by the server.
  class SSLClientSocketImpl::PeerCertificateChain {
   public:
    explicit PeerCertificateChain(STACK_OF(X509) * chain) { Reset(chain); }
    PeerCertificateChain(const PeerCertificateChain& other) { *this = other; }
    ~PeerCertificateChain() {}
    PeerCertificateChain& operator=(const PeerCertificateChain& other);
  
    // Resets the PeerCertificateChain to the set of certificates in|chain|,
    // which may be NULL, indicating to empty the store certificates.
    // Note: If an error occurs, such as being unable to parse the certificates,
    // this will behave as if Reset(NULL) was called.
    void Reset(STACK_OF(X509) * chain);
  
    // Note that when USE_OPENSSL_CERTS is defined, OSCertHandle is X509*
    scoped_refptr<X509Certificate> AsOSChain() const;
  
    size_t size() const {
      if (!openssl_chain_.get())
        return 0;
      return sk_X509_num(openssl_chain_.get());
    }
  
    bool empty() const { return size() == 0; }
  
    X509* Get(size_t index) const {
      DCHECK_LT(index, size());
      return sk_X509_value(openssl_chain_.get(), index);
    }
  
   private:
    bssl::UniquePtr<STACK_OF(X509)> openssl_chain_;
  };
  
  SSLClientSocketImpl::PeerCertificateChain&
  SSLClientSocketImpl::PeerCertificateChain::operator=(
      const PeerCertificateChain& other) {
    if (this == &other)
      return *this;
  
    openssl_chain_.reset(X509_chain_up_ref(other.openssl_chain_.get()));
    return *this;
  }
  
  void SSLClientSocketImpl::PeerCertificateChain::Reset(STACK_OF(X509) * chain) {
    openssl_chain_.reset(chain ? X509_chain_up_ref(chain) : NULL);
  }
  
  scoped_refptr<X509Certificate>
  SSLClientSocketImpl::PeerCertificateChain::AsOSChain() const {
    // DER-encode the chain and convert to a platform certificate handle.
    std::vector<std::string> chain;
    chain.reserve(sk_X509_num(openssl_chain_.get()));
    for (size_t i = 0; i < sk_X509_num(openssl_chain_.get()); ++i) {
      X509* x = sk_X509_value(openssl_chain_.get(), i);
      // Note: This intentionally avoids using x509_util::GetDER(), which may
      // cache the encoded DER on |x|, as |x| is shared with the underlying
      // socket (SSL*) this chain belongs to. As the DER will only be used
      // once in //net, within this code, this avoids needlessly caching
      // additional data. See https://crbug.com/642082
      int len = i2d_X509(x, nullptr);
      if (len < 0)
        return nullptr;
      std::string cert;
      uint8_t* ptr = reinterpret_cast<uint8_t*>(base::WriteInto(&cert, len + 1));
      len = i2d_X509(x, &ptr);
      if (len < 0) {
        NOTREACHED();
        return nullptr;
      }
      chain.push_back(std::move(cert));
    }
    std::vector<base::StringPiece> stringpiece_chain;
    for (const auto& cert : chain)
      stringpiece_chain.push_back(cert);
  
    return X509Certificate::CreateFromDERCertChain(stringpiece_chain);
  }
  
  // static
  void SSLClientSocket::ClearSessionCache() {
    SSLClientSocketImpl::SSLContext* context =
        SSLClientSocketImpl::SSLContext::GetInstance();
    context->session_cache()->Flush();
  }
  
  SSLClientSocketImpl::SSLClientSocketImpl(
      std::unique_ptr<ClientSocketHandle> transport_socket,
      const HostPortPair& host_and_port,
      const SSLConfig& ssl_config,
      const SSLClientSocketContext& context)
      : pending_read_error_(kNoPendingResult),
        pending_read_ssl_error_(SSL_ERROR_NONE),
        server_cert_chain_(new PeerCertificateChain(NULL)),
        completed_connect_(false),
        was_ever_used_(false),
        cert_verifier_(context.cert_verifier),
        cert_transparency_verifier_(context.cert_transparency_verifier),
        channel_id_service_(context.channel_id_service),
        tb_was_negotiated_(false),
        tb_negotiated_param_(TB_PARAM_ECDSAP256),
        tb_signature_map_(10),
        transport_(std::move(transport_socket)),
        host_and_port_(host_and_port),
        ssl_config_(ssl_config),
        ssl_session_cache_shard_(context.ssl_session_cache_shard),
        next_handshake_state_(STATE_NONE),
        disconnected_(false),
        negotiated_protocol_(kProtoUnknown),
        channel_id_sent_(false),
        certificate_verified_(false),
        certificate_requested_(false),
        signature_result_(kNoPendingResult),
        transport_security_state_(context.transport_security_state),
        policy_enforcer_(context.ct_policy_enforcer),
        pkp_bypassed_(false),
        net_log_(transport_->socket()->NetLog()),
        weak_factory_(this) {
    CHECK(cert_verifier_);
    CHECK(transport_security_state_);
    CHECK(cert_transparency_verifier_);
    CHECK(policy_enforcer_);
  }
  
  SSLClientSocketImpl::~SSLClientSocketImpl() {
    Disconnect();
  }
  
  #if !defined(OS_NACL)
  void SSLClientSocketImpl::SetSSLKeyLogFile(
      const base::FilePath& ssl_keylog_file,
      const scoped_refptr<base::SequencedTaskRunner>& task_runner) {
    SSLContext::GetInstance()->SetSSLKeyLogFile(ssl_keylog_file, task_runner);
  }
  #endif
  
  void SSLClientSocketImpl::GetSSLCertRequestInfo(
      SSLCertRequestInfo* cert_request_info) {
    cert_request_info->host_and_port = host_and_port_;
    cert_request_info->cert_authorities = cert_authorities_;
    cert_request_info->cert_key_types = cert_key_types_;
  }
  
  ChannelIDService* SSLClientSocketImpl::GetChannelIDService() const {
    return channel_id_service_;
  }
  
  Error SSLClientSocketImpl::GetTokenBindingSignature(crypto::ECPrivateKey* key,
                                                      TokenBindingType tb_type,
                                                      std::vector<uint8_t>* out) {
    // The same key will be used across multiple requests to sign the same value,
    // so the signature is cached.
    std::string raw_public_key;
    if (!key->ExportRawPublicKey(&raw_public_key))
      return ERR_FAILED;
    auto it = tb_signature_map_.Get(std::make_pair(tb_type, raw_public_key));
    if (it != tb_signature_map_.end()) {
      *out = it->second;
      return OK;
    }
  
    uint8_t tb_ekm_buf[32];
    static const char kTokenBindingExporterLabel[] = "EXPORTER-Token-Binding";
    if (!SSL_export_keying_material(ssl_.get(), tb_ekm_buf, sizeof(tb_ekm_buf),
                                    kTokenBindingExporterLabel,
                                    strlen(kTokenBindingExporterLabel), nullptr,
                                    0, false /* no context */)) {
      return ERR_FAILED;
    }
  
    if (!CreateTokenBindingSignature(
            base::StringPiece(reinterpret_cast<char*>(tb_ekm_buf),
                              sizeof(tb_ekm_buf)),
            tb_type, key, out))
      return ERR_FAILED;
  
    tb_signature_map_.Put(std::make_pair(tb_type, raw_public_key), *out);
    return OK;
  }
  
  crypto::ECPrivateKey* SSLClientSocketImpl::GetChannelIDKey() const {
    return channel_id_key_.get();
  }
  
  int SSLClientSocketImpl::ExportKeyingMaterial(const base::StringPiece& label,
                                                bool has_context,
                                                const base::StringPiece& context,
                                                unsigned char* out,
                                                unsigned int outlen) {
    if (!IsConnected())
      return ERR_SOCKET_NOT_CONNECTED;
  
    crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
  
    if (!SSL_export_keying_material(
            ssl_.get(), out, outlen, label.data(), label.size(),
            reinterpret_cast<const unsigned char*>(context.data()),
            context.length(), has_context ? 1 : 0)) {
      LOG(ERROR) << "Failed to export keying material.";
      return ERR_FAILED;
    }
  
    return OK;
  }
  
  int SSLClientSocketImpl::Connect(const CompletionCallback& callback) {
    // Although StreamSocket does allow calling Connect() after Disconnect(),
    // this has never worked for layered sockets. CHECK to detect any consumers
    // reconnecting an SSL socket.
    //
    // TODO(davidben,mmenke): Remove this API feature. See
    // https://crbug.com/499289.
    CHECK(!disconnected_);
  
    net_log_.BeginEvent(NetLogEventType::SSL_CONNECT);
  
    // Set up new ssl object.
    int rv = Init();
    if (rv != OK) {
      LogConnectEndEvent(rv);
      return rv;
    }
  
    // Set SSL to client mode. Handshake happens in the loop below.
    SSL_set_connect_state(ssl_.get());
  
    next_handshake_state_ = STATE_HANDSHAKE;
    rv = DoHandshakeLoop(OK);
    if (rv == ERR_IO_PENDING) {
      user_connect_callback_ = callback;
    } else {
      LogConnectEndEvent(rv);
    }
  
    return rv > OK ? OK : rv;
  }
  
  void SSLClientSocketImpl::Disconnect() {
    disconnected_ = true;
  
    // Shut down anything that may call us back.
    cert_verifier_request_.reset();
    channel_id_request_.Cancel();
    weak_factory_.InvalidateWeakPtrs();
    transport_adapter_.reset();
  
    // Release user callbacks.
    user_connect_callback_.Reset();
    user_read_callback_.Reset();
    user_write_callback_.Reset();
    user_read_buf_ = NULL;
    user_read_buf_len_ = 0;
    user_write_buf_ = NULL;
    user_write_buf_len_ = 0;
  
    transport_->socket()->Disconnect();
  }
  
  bool SSLClientSocketImpl::IsConnected() const {
    // If the handshake has not yet completed or the socket has been explicitly
    // disconnected.
    if (!completed_connect_ || disconnected_)
      return false;
    // If an asynchronous operation is still pending.
    if (user_read_buf_.get() || user_write_buf_.get())
      return true;
  
    return transport_->socket()->IsConnected();
  }
  
  bool SSLClientSocketImpl::IsConnectedAndIdle() const {
    // If the handshake has not yet completed or the socket has been explicitly
    // disconnected.
    if (!completed_connect_ || disconnected_)
      return false;
    // If an asynchronous operation is still pending.
    if (user_read_buf_.get() || user_write_buf_.get())
      return false;
  
    // If there is data read from the network that has not yet been consumed, do
    // not treat the connection as idle.
    //
    // Note that this does not check whether there is ciphertext that has not yet
    // been flushed to the network. |Write| returns early, so this can cause race
    // conditions which cause a socket to not be treated reusable when it should
    // be. See https://crbug.com/466147.
    if (transport_adapter_->HasPendingReadData())
      return false;
  
    return transport_->socket()->IsConnectedAndIdle();
  }
  
  int SSLClientSocketImpl::GetPeerAddress(IPEndPoint* addressList) const {
    return transport_->socket()->GetPeerAddress(addressList);
  }
  
  int SSLClientSocketImpl::GetLocalAddress(IPEndPoint* addressList) const {
    return transport_->socket()->GetLocalAddress(addressList);
  }
  
  const NetLogWithSource& SSLClientSocketImpl::NetLog() const {
    return net_log_;
  }
  
  void SSLClientSocketImpl::SetSubresourceSpeculation() {
    if (transport_.get() && transport_->socket()) {
      transport_->socket()->SetSubresourceSpeculation();
    } else {
      NOTREACHED();
    }
  }
  
  void SSLClientSocketImpl::SetOmniboxSpeculation() {
    if (transport_.get() && transport_->socket()) {
      transport_->socket()->SetOmniboxSpeculation();
    } else {
      NOTREACHED();
    }
  }
  
  bool SSLClientSocketImpl::WasEverUsed() const {
    return was_ever_used_;
  }
  
  bool SSLClientSocketImpl::WasNpnNegotiated() const {
    return negotiated_protocol_ != kProtoUnknown;
  }
  
  NextProto SSLClientSocketImpl::GetNegotiatedProtocol() const {
    return negotiated_protocol_;
  }
  
  bool SSLClientSocketImpl::GetSSLInfo(SSLInfo* ssl_info) {
    ssl_info->Reset();
    if (server_cert_chain_->empty())
      return false;
  
    ssl_info->cert = server_cert_verify_result_.verified_cert;
    ssl_info->unverified_cert = server_cert_;
    ssl_info->cert_status = server_cert_verify_result_.cert_status;
    ssl_info->is_issued_by_known_root =
        server_cert_verify_result_.is_issued_by_known_root;
    ssl_info->pkp_bypassed = pkp_bypassed_;
    ssl_info->public_key_hashes = server_cert_verify_result_.public_key_hashes;
    ssl_info->client_cert_sent =
        ssl_config_.send_client_cert && ssl_config_.client_cert.get();
    ssl_info->channel_id_sent = channel_id_sent_;
    ssl_info->token_binding_negotiated = tb_was_negotiated_;
    ssl_info->token_binding_key_param = tb_negotiated_param_;
    ssl_info->pinning_failure_log = pinning_failure_log_;
    ssl_info->ocsp_result = server_cert_verify_result_.ocsp_result;
  
    AddCTInfoToSSLInfo(ssl_info);
  
    const SSL_CIPHER* cipher = SSL_get_current_cipher(ssl_.get());
    CHECK(cipher);
    ssl_info->security_bits = SSL_CIPHER_get_bits(cipher, NULL);
    // Historically, the "group" was known as "curve".
    ssl_info->key_exchange_group = SSL_get_curve_id(ssl_.get());
  
    SSLConnectionStatusSetCipherSuite(
        static_cast<uint16_t>(SSL_CIPHER_get_id(cipher)),
        &ssl_info->connection_status);
    SSLConnectionStatusSetVersion(GetNetSSLVersion(ssl_.get()),
                                  &ssl_info->connection_status);
  
    if (!SSL_get_secure_renegotiation_support(ssl_.get()))
      ssl_info->connection_status |= SSL_CONNECTION_NO_RENEGOTIATION_EXTENSION;
  
    ssl_info->handshake_type = SSL_session_reused(ssl_.get())
                                   ? SSLInfo::HANDSHAKE_RESUME
                                   : SSLInfo::HANDSHAKE_FULL;
  
    return true;
  }
  
  void SSLClientSocketImpl::GetConnectionAttempts(ConnectionAttempts* out) const {
    out->clear();
  }
  
  int64_t SSLClientSocketImpl::GetTotalReceivedBytes() const {
    return transport_->socket()->GetTotalReceivedBytes();
  }
  
  int SSLClientSocketImpl::Read(IOBuffer* buf,
                                int buf_len,
                                const CompletionCallback& callback) {
    user_read_buf_ = buf;
    user_read_buf_len_ = buf_len;
  
    int rv = DoPayloadRead();
  
    if (rv == ERR_IO_PENDING) {
      user_read_callback_ = callback;
    } else {
      if (rv > 0)
        was_ever_used_ = true;
      user_read_buf_ = NULL;
      user_read_buf_len_ = 0;
    }
  
    return rv;
  }
  
  int SSLClientSocketImpl::Write(IOBuffer* buf,
                                 int buf_len,
                                 const CompletionCallback& callback) {
    user_write_buf_ = buf;
    user_write_buf_len_ = buf_len;
  
    int rv = DoPayloadWrite();
  
    if (rv == ERR_IO_PENDING) {
      user_write_callback_ = callback;
    } else {
      if (rv > 0)
        was_ever_used_ = true;
      user_write_buf_ = NULL;
      user_write_buf_len_ = 0;
    }
  
    return rv;
  }
  
  int SSLClientSocketImpl::SetReceiveBufferSize(int32_t size) {
    return transport_->socket()->SetReceiveBufferSize(size);
  }
  
  int SSLClientSocketImpl::SetSendBufferSize(int32_t size) {
    return transport_->socket()->SetSendBufferSize(size);
  }
  
  void SSLClientSocketImpl::OnReadReady() {
    // During a renegotiation, either Read or Write calls may be blocked on a
    // transport read.
    RetryAllOperations();
  }
  
  void SSLClientSocketImpl::OnWriteReady() {
    // During a renegotiation, either Read or Write calls may be blocked on a
    // transport read.
    RetryAllOperations();
  }
  
  int SSLClientSocketImpl::Init() {
    DCHECK(!ssl_);
  
  #if defined(USE_NSS_CERTS)
    if (ssl_config_.cert_io_enabled) {
      // TODO(davidben): Move this out of SSLClientSocket. See
      // https://crbug.com/539520.
      EnsureNSSHttpIOInit();
    }
  #endif
  
    SSLContext* context = SSLContext::GetInstance();
    crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
  
    ssl_.reset(SSL_new(context->ssl_ctx()));
    if (!ssl_ || !context->SetClientSocketForSSL(ssl_.get(), this))
      return ERR_UNEXPECTED;
  
    // SNI should only contain valid DNS hostnames, not IP addresses (see RFC
    // 6066, Section 3).
    //
    // TODO(rsleevi): Should this code allow hostnames that violate the LDH rule?
    // See https://crbug.com/496472 and https://crbug.com/496468 for discussion.
    IPAddress unused;
    if (!unused.AssignFromIPLiteral(host_and_port_.host()) &&
        !SSL_set_tlsext_host_name(ssl_.get(), host_and_port_.host().c_str())) {
      return ERR_UNEXPECTED;
    }
  
    bssl::UniquePtr<SSL_SESSION> session =
        context->session_cache()->Lookup(GetSessionCacheKey());
    if (session)
      SSL_set_session(ssl_.get(), session.get());
  
    transport_adapter_.reset(new SocketBIOAdapter(
        transport_->socket(), GetBufferSize("SSLBufferSizeRecv"),
        GetBufferSize("SSLBufferSizeSend"), this));
    BIO* transport_bio = transport_adapter_->bio();
  
    BIO_up_ref(transport_bio);  // SSL_set0_rbio takes ownership.
    SSL_set0_rbio(ssl_.get(), transport_bio);
  
    BIO_up_ref(transport_bio);  // SSL_set0_wbio takes ownership.
    SSL_set0_wbio(ssl_.get(), transport_bio);
  
    DCHECK_LT(SSL3_VERSION, ssl_config_.version_min);
    DCHECK_LT(SSL3_VERSION, ssl_config_.version_max);
    if (!SSL_set_min_proto_version(ssl_.get(), ssl_config_.version_min) ||
        !SSL_set_max_proto_version(ssl_.get(), ssl_config_.version_max)) {
      return ERR_UNEXPECTED;
    }
  
    // OpenSSL defaults some options to on, others to off. To avoid ambiguity,
    // set everything we care about to an absolute value.
    SslSetClearMask options;
    options.ConfigureFlag(SSL_OP_NO_COMPRESSION, true);
  
    // TODO(joth): Set this conditionally, see http://crbug.com/55410
    options.ConfigureFlag(SSL_OP_LEGACY_SERVER_CONNECT, true);
  
    SSL_set_options(ssl_.get(), options.set_mask);
    SSL_clear_options(ssl_.get(), options.clear_mask);
  
    // Same as above, this time for the SSL mode.
    SslSetClearMask mode;
  
    mode.ConfigureFlag(SSL_MODE_RELEASE_BUFFERS, true);
    mode.ConfigureFlag(SSL_MODE_CBC_RECORD_SPLITTING, true);
  
    mode.ConfigureFlag(SSL_MODE_ENABLE_FALSE_START,
                       ssl_config_.false_start_enabled);
  
    SSL_set_mode(ssl_.get(), mode.set_mask);
    SSL_clear_mode(ssl_.get(), mode.clear_mask);
  
    std::string command;
    if (SSLClientSocket::IsPostQuantumExperimentEnabled()) {
      // These are experimental, non-standard ciphersuites.  They are part of an
      // experiment in post-quantum cryptography.  They're not intended to
      // represent a de-facto standard, and will be removed from BoringSSL in
      // ~2018.
      if (EVP_has_aes_hardware()) {
        command.append(
            "CECPQ1-RSA-AES256-GCM-SHA384:"
            "CECPQ1-ECDSA-AES256-GCM-SHA384:");
      }
      command.append(
          "CECPQ1-RSA-CHACHA20-POLY1305-SHA256:"
          "CECPQ1-ECDSA-CHACHA20-POLY1305-SHA256:");
      if (!EVP_has_aes_hardware()) {
        command.append(
            "CECPQ1-RSA-AES256-GCM-SHA384:"
            "CECPQ1-ECDSA-AES256-GCM-SHA384:");
      }
    }
  
    // Use BoringSSL defaults, but disable HMAC-SHA256 and HMAC-SHA384 ciphers
    // (note that SHA256 and SHA384 only select legacy CBC ciphers). Also disable
    // DHE_RSA_WITH_AES_256_GCM_SHA384. Historically, AES_256_GCM was not
    // supported. As DHE is being deprecated, don't add a cipher only to remove
    // it immediately.
    //
    // TODO(davidben): Remove the DHE_RSA_WITH_AES_256_GCM_SHA384 exclusion when
    // the DHEEnabled administrative policy expires.
    command.append("ALL:!SHA256:!SHA384:!DHE-RSA-AES256-GCM-SHA384:!aPSK:!RC4");
  
    if (ssl_config_.require_ecdhe)
      command.append(":!kRSA:!kDHE");
  
    if (!ssl_config_.deprecated_cipher_suites_enabled) {
      // Only offer DHE on the second handshake. https://crbug.com/538690
      command.append(":!kDHE");
    }
  
    // Additionally disable HMAC-SHA1 ciphers in ECDSA. These are the remaining
    // CBC-mode ECDSA ciphers.
    if (!AreLegacyECDSACiphersEnabled())
      command.append("!ECDSA+SHA1");
  
    // Remove any disabled ciphers.
    for (uint16_t id : ssl_config_.disabled_cipher_suites) {
      const SSL_CIPHER* cipher = SSL_get_cipher_by_value(id);
      if (cipher) {
        command.append(":!");
        command.append(SSL_CIPHER_get_name(cipher));
      }
    }
  
    int rv = SSL_set_cipher_list(ssl_.get(), command.c_str());
    // If this fails (rv = 0) it means there are no ciphers enabled on this SSL.
    // This will almost certainly result in the socket failing to complete the
    // handshake at which point the appropriate error is bubbled up to the client.
    LOG_IF(WARNING, rv != 1) << "SSL_set_cipher_list('" << command << "') "
                                                                      "returned "
                             << rv;
  
    // TLS channel ids.
    if (IsChannelIDEnabled()) {
      SSL_enable_tls_channel_id(ssl_.get());
    }
  
    if (!ssl_config_.alpn_protos.empty()) {
      std::vector<uint8_t> wire_protos =
          SerializeNextProtos(ssl_config_.alpn_protos);
      SSL_set_alpn_protos(ssl_.get(),
                          wire_protos.empty() ? NULL : &wire_protos[0],
                          wire_protos.size());
    }
  
    if (ssl_config_.signed_cert_timestamps_enabled) {
      SSL_enable_signed_cert_timestamps(ssl_.get());
      SSL_enable_ocsp_stapling(ssl_.get());
    }
  
    if (cert_verifier_->SupportsOCSPStapling())
      SSL_enable_ocsp_stapling(ssl_.get());
  
    return OK;
  }
  
  void SSLClientSocketImpl::DoReadCallback(int rv) {
    // Since Run may result in Read being called, clear |user_read_callback_|
    // up front.
    if (rv > 0)
      was_ever_used_ = true;
    user_read_buf_ = NULL;
    user_read_buf_len_ = 0;
    base::ResetAndReturn(&user_read_callback_).Run(rv);
  }
  
  void SSLClientSocketImpl::DoWriteCallback(int rv) {
    // Since Run may result in Write being called, clear |user_write_callback_|
    // up front.
    if (rv > 0)
      was_ever_used_ = true;
    user_write_buf_ = NULL;
    user_write_buf_len_ = 0;
    base::ResetAndReturn(&user_write_callback_).Run(rv);
  }
  
  // TODO(cbentzel): Remove including "base/threading/thread_local.h" and
  // g_first_run_completed once crbug.com/424386 is fixed.
  base::LazyInstance<base::ThreadLocalBoolean>::Leaky g_first_run_completed =
      LAZY_INSTANCE_INITIALIZER;
  
  int SSLClientSocketImpl::DoHandshake() {
    crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
  
    int rv;
  
    // TODO(cbentzel): Leave only 1 call to SSL_do_handshake once crbug.com/424386
    // is fixed.
    if (ssl_config_.send_client_cert && ssl_config_.client_cert.get()) {
      rv = SSL_do_handshake(ssl_.get());
    } else {
      if (g_first_run_completed.Get().Get()) {
        // TODO(cbentzel): Remove ScopedTracker below once crbug.com/424386 is
        // fixed.
        tracked_objects::ScopedTracker tracking_profile(
            FROM_HERE_WITH_EXPLICIT_FUNCTION("424386 SSL_do_handshake()"));
  
        rv = SSL_do_handshake(ssl_.get());
      } else {
        g_first_run_completed.Get().Set(true);
        rv = SSL_do_handshake(ssl_.get());
      }
    }
  
    int net_error = OK;
    if (rv <= 0) {
      int ssl_error = SSL_get_error(ssl_.get(), rv);
      if (ssl_error == SSL_ERROR_WANT_CHANNEL_ID_LOOKUP) {
        // The server supports channel ID. Stop to look one up before returning to
        // the handshake.
        next_handshake_state_ = STATE_CHANNEL_ID_LOOKUP;
        return OK;
      }
      if (ssl_error == SSL_ERROR_WANT_X509_LOOKUP &&
          !ssl_config_.send_client_cert) {
        return ERR_SSL_CLIENT_AUTH_CERT_NEEDED;
      }
      if (ssl_error == SSL_ERROR_WANT_PRIVATE_KEY_OPERATION) {
        DCHECK(ssl_config_.client_private_key);
        DCHECK_NE(kNoPendingResult, signature_result_);
        next_handshake_state_ = STATE_HANDSHAKE;
        return ERR_IO_PENDING;
      }
  
      OpenSSLErrorInfo error_info;
      net_error = MapLastOpenSSLError(ssl_error, err_tracer, &error_info);
      if (net_error == ERR_IO_PENDING) {
        // If not done, stay in this state
        next_handshake_state_ = STATE_HANDSHAKE;
        return ERR_IO_PENDING;
      }
  
      LOG(ERROR) << "handshake failed; returned " << rv << ", SSL error code "
                 << ssl_error << ", net_error " << net_error;
      net_log_.AddEvent(
          NetLogEventType::SSL_HANDSHAKE_ERROR,
          CreateNetLogOpenSSLErrorCallback(net_error, ssl_error, error_info));
    }
  
    next_handshake_state_ = STATE_HANDSHAKE_COMPLETE;
    return net_error;
  }
  
  int SSLClientSocketImpl::DoHandshakeComplete(int result) {
    if (result < 0)
      return result;
  
    // DHE is offered on the deprecated cipher fallback and then rejected
    // afterwards. This is to aid in diagnosing connection failures because a
    // server requires DHE ciphers.
    //
    // TODO(davidben): A few releases after DHE's removal, remove this logic.
    if (!ssl_config_.dhe_enabled &&
        SSL_CIPHER_is_DHE(SSL_get_current_cipher(ssl_.get()))) {
      return ERR_SSL_OBSOLETE_CIPHER;
    }
  
    // Check that if token binding was negotiated, then extended master secret
    // and renegotiation indication must also be negotiated.
    if (tb_was_negotiated_ &&
        !(SSL_get_extms_support(ssl_.get()) &&
          SSL_get_secure_renegotiation_support(ssl_.get()))) {
      return ERR_SSL_PROTOCOL_ERROR;
    }
  
    const uint8_t* alpn_proto = NULL;
    unsigned alpn_len = 0;
    SSL_get0_alpn_selected(ssl_.get(), &alpn_proto, &alpn_len);
    if (alpn_len > 0) {
      base::StringPiece proto(reinterpret_cast<const char*>(alpn_proto),
                              alpn_len);
      negotiated_protocol_ = NextProtoFromString(proto);
    }
  
    RecordNegotiatedProtocol();
    RecordChannelIDSupport();
  
    const uint8_t* ocsp_response_raw;
    size_t ocsp_response_len;
    SSL_get0_ocsp_response(ssl_.get(), &ocsp_response_raw, &ocsp_response_len);
    std::string ocsp_response;
    if (ocsp_response_len > 0) {
      ocsp_response_.assign(reinterpret_cast<const char*>(ocsp_response_raw),
                            ocsp_response_len);
    }
    set_stapled_ocsp_response_received(ocsp_response_len != 0);
    UMA_HISTOGRAM_BOOLEAN("Net.OCSPResponseStapled", ocsp_response_len != 0);
  
    const uint8_t* sct_list;
    size_t sct_list_len;
    SSL_get0_signed_cert_timestamp_list(ssl_.get(), &sct_list, &sct_list_len);
    set_signed_cert_timestamps_received(sct_list_len != 0);
  
    if (IsRenegotiationAllowed())
      SSL_set_renegotiate_mode(ssl_.get(), ssl_renegotiate_freely);
  
    uint16_t signature_algorithm = SSL_get_peer_signature_algorithm(ssl_.get());
    if (signature_algorithm != 0) {
      UMA_HISTOGRAM_SPARSE_SLOWLY("Net.SSLSignatureAlgorithm",
                                  signature_algorithm);
    }
  
    // Verify the certificate.
    UpdateServerCert();
    next_handshake_state_ = STATE_VERIFY_CERT;
    return OK;
  }
  
  int SSLClientSocketImpl::DoChannelIDLookup() {
    NetLogParametersCallback callback = base::Bind(
        &NetLogChannelIDLookupCallback, base::Unretained(channel_id_service_));
    net_log_.BeginEvent(NetLogEventType::SSL_GET_CHANNEL_ID, callback);
    next_handshake_state_ = STATE_CHANNEL_ID_LOOKUP_COMPLETE;
    return channel_id_service_->GetOrCreateChannelID(
        host_and_port_.host(), &channel_id_key_,
        base::Bind(&SSLClientSocketImpl::OnHandshakeIOComplete,
                   base::Unretained(this)),
        &channel_id_request_);
  }
  
  int SSLClientSocketImpl::DoChannelIDLookupComplete(int result) {
    net_log_.EndEvent(NetLogEventType::SSL_GET_CHANNEL_ID,
                      base::Bind(&NetLogChannelIDLookupCompleteCallback,
                                 channel_id_key_.get(), result));
    if (result < 0)
      return result;
  
    // Hand the key to OpenSSL. Check for error in case OpenSSL rejects the key
    // type.
    DCHECK(channel_id_key_);
    crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
    if (!SSL_set1_tls_channel_id(ssl_.get(), channel_id_key_->key())) {
      LOG(ERROR) << "Failed to set Channel ID.";
      return ERR_FAILED;
    }
  
    // Return to the handshake.
    channel_id_sent_ = true;
    next_handshake_state_ = STATE_HANDSHAKE;
    return OK;
  }
  
  int SSLClientSocketImpl::DoVerifyCert(int result) {
    DCHECK(!server_cert_chain_->empty());
    DCHECK(start_cert_verification_time_.is_null());
  
    next_handshake_state_ = STATE_VERIFY_CERT_COMPLETE;
  
    // OpenSSL decoded the certificate, but the platform certificate
    // implementation could not. This is treated as a fatal SSL-level protocol
    // error rather than a certificate error. See https://crbug.com/91341.
    if (!server_cert_)
      return ERR_SSL_SERVER_CERT_BAD_FORMAT;
  
    // If the certificate is bad and has been previously accepted, use
    // the previous status and bypass the error.
    CertStatus cert_status;
    if (ssl_config_.IsAllowedBadCert(server_cert_.get(), &cert_status)) {
      server_cert_verify_result_.Reset();
      server_cert_verify_result_.cert_status = cert_status;
      server_cert_verify_result_.verified_cert = server_cert_;
      return OK;
    }
  
    start_cert_verification_time_ = base::TimeTicks::Now();
  
    return cert_verifier_->Verify(
        CertVerifier::RequestParams(server_cert_, host_and_port_.host(),
                                    ssl_config_.GetCertVerifyFlags(),
                                    ocsp_response_, CertificateList()),
        // TODO(davidben): Route the CRLSet through SSLConfig so
        // SSLClientSocket doesn't depend on SSLConfigService.
        SSLConfigService::GetCRLSet().get(), &server_cert_verify_result_,
        base::Bind(&SSLClientSocketImpl::OnHandshakeIOComplete,
                   base::Unretained(this)),
        &cert_verifier_request_, net_log_);
  }
  
  int SSLClientSocketImpl::DoVerifyCertComplete(int result) {
    cert_verifier_request_.reset();
  
    if (!start_cert_verification_time_.is_null()) {
      base::TimeDelta verify_time =
          base::TimeTicks::Now() - start_cert_verification_time_;
      if (result == OK) {
        UMA_HISTOGRAM_TIMES("Net.SSLCertVerificationTime", verify_time);
      } else {
        UMA_HISTOGRAM_TIMES("Net.SSLCertVerificationTimeError", verify_time);
      }
    }
  
    // If the connection was good, check HPKP and CT status simultaneously,
    // but prefer to treat the HPKP error as more serious, if there was one.
    const CertStatus cert_status = server_cert_verify_result_.cert_status;
    if ((result == OK ||
         (IsCertificateError(result) && IsCertStatusMinorError(cert_status)))) {
      int ct_result = VerifyCT();
      TransportSecurityState::PKPStatus pin_validity =
          transport_security_state_->CheckPublicKeyPins(
              host_and_port_, server_cert_verify_result_.is_issued_by_known_root,
              server_cert_verify_result_.public_key_hashes, server_cert_.get(),
              server_cert_verify_result_.verified_cert.get(),
              TransportSecurityState::ENABLE_PIN_REPORTS, &pinning_failure_log_);
      switch (pin_validity) {
        case TransportSecurityState::PKPStatus::VIOLATED:
          server_cert_verify_result_.cert_status |=
              CERT_STATUS_PINNED_KEY_MISSING;
          result = ERR_SSL_PINNED_KEY_NOT_IN_CERT_CHAIN;
          break;
        case TransportSecurityState::PKPStatus::BYPASSED:
          pkp_bypassed_ = true;
        // Fall through.
        case TransportSecurityState::PKPStatus::OK:
          // Do nothing.
          break;
      }
      if (result != ERR_SSL_PINNED_KEY_NOT_IN_CERT_CHAIN && ct_result != OK)
        result = ct_result;
    }
  
    if (result == OK) {
      DCHECK(!certificate_verified_);
      certificate_verified_ = true;
      MaybeCacheSession();
      SSLInfo ssl_info;
      bool ok = GetSSLInfo(&ssl_info);
      DCHECK(ok);
      transport_security_state_->CheckExpectStaple(host_and_port_, ssl_info,
                                                   ocsp_response_);
    }
  
    completed_connect_ = true;
    // Exit DoHandshakeLoop and return the result to the caller to Connect.
    DCHECK_EQ(STATE_NONE, next_handshake_state_);
    return result;
  }
  
  void SSLClientSocketImpl::DoConnectCallback(int rv) {
    if (!user_connect_callback_.is_null()) {
      CompletionCallback c = user_connect_callback_;
      user_connect_callback_.Reset();
      c.Run(rv > OK ? OK : rv);
    }
  }
  
  void SSLClientSocketImpl::UpdateServerCert() {
    server_cert_chain_->Reset(SSL_get_peer_cert_chain(ssl_.get()));
    server_cert_ = server_cert_chain_->AsOSChain();
    if (server_cert_.get()) {
      net_log_.AddEvent(NetLogEventType::SSL_CERTIFICATES_RECEIVED,
                        base::Bind(&NetLogX509CertificateCallback,
                                   base::Unretained(server_cert_.get())));
    }
  }
  
  void SSLClientSocketImpl::OnHandshakeIOComplete(int result) {
    int rv = DoHandshakeLoop(result);
    if (rv != ERR_IO_PENDING) {
      LogConnectEndEvent(rv);
      DoConnectCallback(rv);
    }
  }
  
  int SSLClientSocketImpl::DoHandshakeLoop(int last_io_result) {
    TRACE_EVENT0("net", "SSLClientSocketImpl::DoHandshakeLoop");
    int rv = last_io_result;
    do {
      // Default to STATE_NONE for next state.
      // (This is a quirk carried over from the windows
      // implementation.  It makes reading the logs a bit harder.)
      // State handlers can and often do call GotoState just
      // to stay in the current state.
      State state = next_handshake_state_;
      next_handshake_state_ = STATE_NONE;
      switch (state) {
        case STATE_HANDSHAKE:
          rv = DoHandshake();
          break;
        case STATE_HANDSHAKE_COMPLETE:
          rv = DoHandshakeComplete(rv);
          break;
        case STATE_CHANNEL_ID_LOOKUP:
          DCHECK_EQ(OK, rv);
          rv = DoChannelIDLookup();
          break;
        case STATE_CHANNEL_ID_LOOKUP_COMPLETE:
          rv = DoChannelIDLookupComplete(rv);
          break;
        case STATE_VERIFY_CERT:
          DCHECK_EQ(OK, rv);
          rv = DoVerifyCert(rv);
          break;
        case STATE_VERIFY_CERT_COMPLETE:
          rv = DoVerifyCertComplete(rv);
          break;
        case STATE_NONE:
        default:
          rv = ERR_UNEXPECTED;
          NOTREACHED() << "unexpected state" << state;
          break;
      }
    } while (rv != ERR_IO_PENDING && next_handshake_state_ != STATE_NONE);
    return rv;
  }
  
  int SSLClientSocketImpl::DoPayloadRead() {
    crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
  
    DCHECK_LT(0, user_read_buf_len_);
    DCHECK(user_read_buf_.get());
  
    int rv;
    if (pending_read_error_ != kNoPendingResult) {
      rv = pending_read_error_;
      pending_read_error_ = kNoPendingResult;
      if (rv == 0) {
        net_log_.AddByteTransferEvent(NetLogEventType::SSL_SOCKET_BYTES_RECEIVED,
                                      rv, user_read_buf_->data());
      } else {
        net_log_.AddEvent(
            NetLogEventType::SSL_READ_ERROR,
            CreateNetLogOpenSSLErrorCallback(rv, pending_read_ssl_error_,
                                             pending_read_error_info_));
      }
      pending_read_ssl_error_ = SSL_ERROR_NONE;
      pending_read_error_info_ = OpenSSLErrorInfo();
      return rv;
    }
  
    int total_bytes_read = 0;
    int ssl_ret;
    do {
      ssl_ret = SSL_read(ssl_.get(), user_read_buf_->data() + total_bytes_read,
                         user_read_buf_len_ - total_bytes_read);
      if (ssl_ret > 0)
        total_bytes_read += ssl_ret;
    } while (total_bytes_read < user_read_buf_len_ && ssl_ret > 0);
  
    // Although only the final SSL_read call may have failed, the failure needs to
    // processed immediately, while the information still available in OpenSSL's
    // error queue.
    if (ssl_ret <= 0) {
      // A zero return from SSL_read may mean any of:
      // - The underlying BIO_read returned 0.
      // - The peer sent a close_notify.
      // - Any arbitrary error. https://crbug.com/466303
      //
      // TransportReadComplete converts the first to an ERR_CONNECTION_CLOSED
      // error, so it does not occur. The second and third are distinguished by
      // SSL_ERROR_ZERO_RETURN.
      pending_read_ssl_error_ = SSL_get_error(ssl_.get(), ssl_ret);
      if (pending_read_ssl_error_ == SSL_ERROR_ZERO_RETURN) {
        pending_read_error_ = 0;
      } else if (pending_read_ssl_error_ == SSL_ERROR_WANT_X509_LOOKUP &&
                 !ssl_config_.send_client_cert) {
        pending_read_error_ = ERR_SSL_CLIENT_AUTH_CERT_NEEDED;
      } else if (pending_read_ssl_error_ ==
                 SSL_ERROR_WANT_PRIVATE_KEY_OPERATION) {
        DCHECK(ssl_config_.client_private_key);
        DCHECK_NE(kNoPendingResult, signature_result_);
        pending_read_error_ = ERR_IO_PENDING;
      } else {
        pending_read_error_ = MapLastOpenSSLError(
            pending_read_ssl_error_, err_tracer, &pending_read_error_info_);
      }
  
      // Many servers do not reliably send a close_notify alert when shutting down
      // a connection, and instead terminate the TCP connection. This is reported
      // as ERR_CONNECTION_CLOSED. Because of this, map the unclean shutdown to a
      // graceful EOF, instead of treating it as an error as it should be.
      if (pending_read_error_ == ERR_CONNECTION_CLOSED)
        pending_read_error_ = 0;
    }
  
    if (total_bytes_read > 0) {
      // Return any bytes read to the caller. The error will be deferred to the
      // next call of DoPayloadRead.
      rv = total_bytes_read;
  
      // Do not treat insufficient data as an error to return in the next call to
      // DoPayloadRead() - instead, let the call fall through to check SSL_read()
      // again. The transport may have data available by then.
      if (pending_read_error_ == ERR_IO_PENDING)
        pending_read_error_ = kNoPendingResult;
    } else {
      // No bytes were returned. Return the pending read error immediately.
      DCHECK_NE(kNoPendingResult, pending_read_error_);
      rv = pending_read_error_;
      pending_read_error_ = kNoPendingResult;
    }
  
    if (rv >= 0) {
      net_log_.AddByteTransferEvent(NetLogEventType::SSL_SOCKET_BYTES_RECEIVED,
                                    rv, user_read_buf_->data());
    } else if (rv != ERR_IO_PENDING) {
      net_log_.AddEvent(
          NetLogEventType::SSL_READ_ERROR,
          CreateNetLogOpenSSLErrorCallback(rv, pending_read_ssl_error_,
                                           pending_read_error_info_));
      pending_read_ssl_error_ = SSL_ERROR_NONE;
      pending_read_error_info_ = OpenSSLErrorInfo();
    }
    return rv;
  }
  
  int SSLClientSocketImpl::DoPayloadWrite() {
    crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
    int rv = SSL_write(ssl_.get(), user_write_buf_->data(), user_write_buf_len_);
  
    if (rv >= 0) {
      net_log_.AddByteTransferEvent(NetLogEventType::SSL_SOCKET_BYTES_SENT, rv,
                                    user_write_buf_->data());
      return rv;
    }
  
    int ssl_error = SSL_get_error(ssl_.get(), rv);
    if (ssl_error == SSL_ERROR_WANT_PRIVATE_KEY_OPERATION)
      return ERR_IO_PENDING;
    OpenSSLErrorInfo error_info;
    int net_error = MapLastOpenSSLError(ssl_error, err_tracer, &error_info);
  
    if (net_error != ERR_IO_PENDING) {
      net_log_.AddEvent(
          NetLogEventType::SSL_WRITE_ERROR,
          CreateNetLogOpenSSLErrorCallback(net_error, ssl_error, error_info));
    }
    return net_error;
  }
  
  void SSLClientSocketImpl::RetryAllOperations() {
    // SSL_do_handshake, SSL_read, and SSL_write may all be retried when blocked,
    // so retry all operations for simplicity. (Otherwise, SSL_get_error for each
    // operation may be remembered to retry only the blocked ones.)
  
    if (next_handshake_state_ == STATE_HANDSHAKE) {
      // In handshake phase. The parameter to OnHandshakeIOComplete is unused.
      OnHandshakeIOComplete(OK);
      return;
    }
  
    int rv_read = ERR_IO_PENDING;
    int rv_write = ERR_IO_PENDING;
    if (user_read_buf_)
      rv_read = DoPayloadRead();
    if (user_write_buf_)
      rv_write = DoPayloadWrite();
  
    // Performing the Read callback may cause |this| to be deleted. If this
    // happens, the Write callback should not be invoked. Guard against this by
    // holding a WeakPtr to |this| and ensuring it's still valid.
    base::WeakPtr<SSLClientSocketImpl> guard(weak_factory_.GetWeakPtr());
    if (rv_read != ERR_IO_PENDING)
      DoReadCallback(rv_read);
  
    if (!guard.get())
      return;
  
    if (rv_write != ERR_IO_PENDING)
      DoWriteCallback(rv_write);
  }
  
  int SSLClientSocketImpl::VerifyCT() {
    const uint8_t* sct_list_raw;
    size_t sct_list_len;
    SSL_get0_signed_cert_timestamp_list(ssl_.get(), &sct_list_raw, &sct_list_len);
    std::string sct_list;
    if (sct_list_len > 0)
      sct_list.assign(reinterpret_cast<const char*>(sct_list_raw), sct_list_len);
  
    // Note that this is a completely synchronous operation: The CT Log Verifier
    // gets all the data it needs for SCT verification and does not do any
    // external communication.
    cert_transparency_verifier_->Verify(
        server_cert_verify_result_.verified_cert.get(), ocsp_response_, sct_list,
        &ct_verify_result_.scts, net_log_);
  
    ct_verify_result_.ct_policies_applied = true;
    ct_verify_result_.ev_policy_compliance =
        ct::EVPolicyCompliance::EV_POLICY_DOES_NOT_APPLY;
  
    SCTList verified_scts =
        ct::SCTsMatchingStatus(ct_verify_result_.scts, ct::SCT_STATUS_OK);
  
    if (server_cert_verify_result_.cert_status & CERT_STATUS_IS_EV) {
      scoped_refptr<ct::EVCertsWhitelist> ev_whitelist =
          SSLConfigService::GetEVCertsWhitelist();
      ct::EVPolicyCompliance ev_policy_compliance =
          policy_enforcer_->DoesConformToCTEVPolicy(
              server_cert_verify_result_.verified_cert.get(), ev_whitelist.get(),
              verified_scts, net_log_);
      ct_verify_result_.ev_policy_compliance = ev_policy_compliance;
      if (ev_policy_compliance !=
              ct::EVPolicyCompliance::EV_POLICY_DOES_NOT_APPLY &&
          ev_policy_compliance !=
              ct::EVPolicyCompliance::EV_POLICY_COMPLIES_VIA_WHITELIST &&
          ev_policy_compliance !=
              ct::EVPolicyCompliance::EV_POLICY_COMPLIES_VIA_SCTS) {
        server_cert_verify_result_.cert_status |=
            CERT_STATUS_CT_COMPLIANCE_FAILED;
        server_cert_verify_result_.cert_status &= ~CERT_STATUS_IS_EV;
      }
    }
    ct_verify_result_.cert_policy_compliance =
        policy_enforcer_->DoesConformToCertPolicy(
            server_cert_verify_result_.verified_cert.get(), verified_scts,
            net_log_);
  
    if (ct_verify_result_.cert_policy_compliance !=
            ct::CertPolicyCompliance::CERT_POLICY_COMPLIES_VIA_SCTS &&
        ct_verify_result_.cert_policy_compliance !=
            ct::CertPolicyCompliance::CERT_POLICY_BUILD_NOT_TIMELY &&
        transport_security_state_->ShouldRequireCT(
            host_and_port_.host(), server_cert_verify_result_.verified_cert.get(),
            server_cert_verify_result_.public_key_hashes)) {
      server_cert_verify_result_.cert_status |=
          CERT_STATUS_CERTIFICATE_TRANSPARENCY_REQUIRED;
      return ERR_CERTIFICATE_TRANSPARENCY_REQUIRED;
    }
  
    return OK;
  }
  
  int SSLClientSocketImpl::ClientCertRequestCallback(SSL* ssl) {
    DCHECK(ssl == ssl_.get());
  
    net_log_.AddEvent(NetLogEventType::SSL_CLIENT_CERT_REQUESTED);
    certificate_requested_ = true;
  
    // Clear any currently configured certificates.
    SSL_certs_clear(ssl_.get());
  
  #if defined(OS_IOS)
    // TODO(droger): Support client auth on iOS. See http://crbug.com/145954).
    LOG(WARNING) << "Client auth is not supported";
  #else   // !defined(OS_IOS)
    if (!ssl_config_.send_client_cert) {
      // First pass: we know that a client certificate is needed, but we do not
      // have one at hand.
      STACK_OF(X509_NAME)* authorities = SSL_get_client_CA_list(ssl);
      for (size_t i = 0; i < sk_X509_NAME_num(authorities); i++) {
        X509_NAME* ca_name = (X509_NAME*)sk_X509_NAME_value(authorities, i);
        unsigned char* str = NULL;
        int length = i2d_X509_NAME(ca_name, &str);
        cert_authorities_.push_back(std::string(
            reinterpret_cast<const char*>(str), static_cast<size_t>(length)));
        OPENSSL_free(str);
      }
  
      const unsigned char* client_cert_types;
      size_t num_client_cert_types =
          SSL_get0_certificate_types(ssl, &client_cert_types);
      for (size_t i = 0; i < num_client_cert_types; i++) {
        cert_key_types_.push_back(
            static_cast<SSLClientCertType>(client_cert_types[i]));
      }
  
      // Suspends handshake. SSL_get_error will return SSL_ERROR_WANT_X509_LOOKUP.
      return -1;
    }
  
    // Second pass: a client certificate should have been selected.
    if (ssl_config_.client_cert.get()) {
      bssl::UniquePtr<X509> leaf_x509 =
          OSCertHandleToOpenSSL(ssl_config_.client_cert->os_cert_handle());
      if (!leaf_x509) {
        LOG(WARNING) << "Failed to import certificate";
        OpenSSLPutNetError(FROM_HERE, ERR_SSL_CLIENT_AUTH_CERT_BAD_FORMAT);
        return -1;
      }
  
      bssl::UniquePtr<STACK_OF(X509)> chain = OSCertHandlesToOpenSSL(
          ssl_config_.client_cert->GetIntermediateCertificates());
      if (!chain) {
        LOG(WARNING) << "Failed to import intermediate certificates";
        OpenSSLPutNetError(FROM_HERE, ERR_SSL_CLIENT_AUTH_CERT_BAD_FORMAT);
        return -1;
      }
  
      if (!SSL_use_certificate(ssl_.get(), leaf_x509.get()) ||
          !SSL_set1_chain(ssl_.get(), chain.get())) {
        LOG(WARNING) << "Failed to set client certificate";
        return -1;
      }
  
      if (!ssl_config_.client_private_key) {
        // The caller supplied a null private key. Fail the handshake and surface
        // an appropriate error to the caller.
        LOG(WARNING) << "Client cert found without private key";
        OpenSSLPutNetError(FROM_HERE, ERR_SSL_CLIENT_AUTH_CERT_NO_PRIVATE_KEY);
        return -1;
      }
  
      SSL_set_private_key_method(ssl_.get(), &SSLContext::kPrivateKeyMethod);
  
      std::vector<SSLPrivateKey::Hash> digest_prefs =
          ssl_config_.client_private_key->GetDigestPreferences();
  
      size_t digests_len = digest_prefs.size();
      std::vector<int> digests;
      for (size_t i = 0; i < digests_len; i++) {
        switch (digest_prefs[i]) {
          case SSLPrivateKey::Hash::SHA1:
            digests.push_back(NID_sha1);
            break;
          case SSLPrivateKey::Hash::SHA256:
            digests.push_back(NID_sha256);
            break;
          case SSLPrivateKey::Hash::SHA384:
            digests.push_back(NID_sha384);
            break;
          case SSLPrivateKey::Hash::SHA512:
            digests.push_back(NID_sha512);
            break;
          case SSLPrivateKey::Hash::MD5_SHA1:
            // MD5-SHA1 is not used in TLS 1.2.
            break;
        }
      }
  
      SSL_set_private_key_digest_prefs(ssl_.get(), digests.data(),
                                       digests.size());
  
      int cert_count = 1 + sk_X509_num(chain.get());
      net_log_.AddEvent(NetLogEventType::SSL_CLIENT_CERT_PROVIDED,
                        NetLog::IntCallback("cert_count", cert_count));
      return 1;
    }
  #endif  // defined(OS_IOS)
  
    // Send no client certificate.
    net_log_.AddEvent(NetLogEventType::SSL_CLIENT_CERT_PROVIDED,
                      NetLog::IntCallback("cert_count", 0));
    return 1;
  }
  
  int SSLClientSocketImpl::CertVerifyCallback(X509_STORE_CTX* store_ctx) {
    if (!completed_connect_) {
      // If the first handshake hasn't completed then we accept any certificates
      // because we verify after the handshake.
      return 1;
    }
  
    // Disallow the server certificate to change in a renegotiation.
    if (server_cert_chain_->empty()) {
      LOG(ERROR) << "Received invalid certificate chain between handshakes";
      return 0;
    }
    base::StringPiece old_der, new_der;
    if (store_ctx->cert == NULL ||
        !x509_util::GetDER(server_cert_chain_->Get(0), &old_der) ||
        !x509_util::GetDER(store_ctx->cert, &new_der)) {
      LOG(ERROR) << "Failed to encode certificates";
      return 0;
    }
    if (old_der != new_der) {
      LOG(ERROR) << "Server certificate changed between handshakes";
      return 0;
    }
  
    return 1;
  }
  
  void SSLClientSocketImpl::MaybeCacheSession() {
    // Only cache the session once both a new session has been established and the
    // certificate has been verified. Due to False Start, these events may happen
    // in either order.
    if (!pending_session_ || !certificate_verified_)
      return;
  
    SSLContext::GetInstance()->session_cache()->Insert(GetSessionCacheKey(),
                                                       pending_session_.get());
    pending_session_ = nullptr;
  }
  
  int SSLClientSocketImpl::NewSessionCallback(SSL_SESSION* session) {
    // OpenSSL passes a reference to |session|.
    pending_session_.reset(session);
    MaybeCacheSession();
    return 1;
  }
  
  void SSLClientSocketImpl::AddCTInfoToSSLInfo(SSLInfo* ssl_info) const {
    ssl_info->UpdateCertificateTransparencyInfo(ct_verify_result_);
  }
  
  std::string SSLClientSocketImpl::GetSessionCacheKey() const {
    std::string result = host_and_port_.ToString();
    result.append("/");
    result.append(ssl_session_cache_shard_);
  
    result.append("/");
    if (ssl_config_.deprecated_cipher_suites_enabled)
      result.append("deprecated");
  
    result.append("/");
    if (ssl_config_.channel_id_enabled)
      result.append("channelid");
  
    return result;
  }
  
  bool SSLClientSocketImpl::IsRenegotiationAllowed() const {
    if (tb_was_negotiated_)
      return false;
  
    if (negotiated_protocol_ == kProtoUnknown)
      return ssl_config_.renego_allowed_default;
  
    for (NextProto allowed : ssl_config_.renego_allowed_for_protos) {
      if (negotiated_protocol_ == allowed)
        return true;
    }
    return false;
  }
  
  int SSLClientSocketImpl::PrivateKeyTypeCallback() {
    switch (ssl_config_.client_private_key->GetType()) {
      case SSLPrivateKey::Type::RSA:
        return NID_rsaEncryption;
      case SSLPrivateKey::Type::ECDSA_P256:
        return NID_X9_62_prime256v1;
      case SSLPrivateKey::Type::ECDSA_P384:
        return NID_secp384r1;
      case SSLPrivateKey::Type::ECDSA_P521:
        return NID_secp521r1;
    }
    NOTREACHED();
    return NID_undef;
  }
  
  size_t SSLClientSocketImpl::PrivateKeyMaxSignatureLenCallback() {
    return ssl_config_.client_private_key->GetMaxSignatureLengthInBytes();
  }
  
  ssl_private_key_result_t SSLClientSocketImpl::PrivateKeySignDigestCallback(
      uint8_t* out,
      size_t* out_len,
      size_t max_out,
      const EVP_MD* md,
      const uint8_t* in,
      size_t in_len) {
    DCHECK_EQ(kNoPendingResult, signature_result_);
    DCHECK(signature_.empty());
    DCHECK(ssl_config_.client_private_key);
  
    SSLPrivateKey::Hash hash;
    if (!EVP_MDToPrivateKeyHash(md, &hash)) {
      OpenSSLPutNetError(FROM_HERE, ERR_SSL_CLIENT_AUTH_SIGNATURE_FAILED);
      return ssl_private_key_failure;
    }
  
    net_log_.BeginEvent(
        NetLogEventType::SSL_PRIVATE_KEY_OP,
        base::Bind(&NetLogPrivateKeyOperationCallback,
                   ssl_config_.client_private_key->GetType(), hash));
  
    signature_result_ = ERR_IO_PENDING;
    ssl_config_.client_private_key->SignDigest(
        hash, base::StringPiece(reinterpret_cast<const char*>(in), in_len),
        base::Bind(&SSLClientSocketImpl::OnPrivateKeyComplete,
                   weak_factory_.GetWeakPtr()));
    return ssl_private_key_retry;
  }
  
  ssl_private_key_result_t SSLClientSocketImpl::PrivateKeyCompleteCallback(
      uint8_t* out,
      size_t* out_len,
      size_t max_out) {
    DCHECK_NE(kNoPendingResult, signature_result_);
    DCHECK(ssl_config_.client_private_key);
  
    if (signature_result_ == ERR_IO_PENDING)
      return ssl_private_key_retry;
    if (signature_result_ != OK) {
      OpenSSLPutNetError(FROM_HERE, signature_result_);
      return ssl_private_key_failure;
    }
    if (signature_.size() > max_out) {
      OpenSSLPutNetError(FROM_HERE, ERR_SSL_CLIENT_AUTH_SIGNATURE_FAILED);
      return ssl_private_key_failure;
    }
    memcpy(out, signature_.data(), signature_.size());
    *out_len = signature_.size();
    signature_.clear();
    return ssl_private_key_success;
  }
  
  void SSLClientSocketImpl::OnPrivateKeyComplete(
      Error error,
      const std::vector<uint8_t>& signature) {
    DCHECK_EQ(ERR_IO_PENDING, signature_result_);
    DCHECK(signature_.empty());
    DCHECK(ssl_config_.client_private_key);
  
    net_log_.EndEventWithNetErrorCode(NetLogEventType::SSL_PRIVATE_KEY_OP, error);
  
    signature_result_ = error;
    if (signature_result_ == OK)
      signature_ = signature;
  
    // During a renegotiation, either Read or Write calls may be blocked on an
    // asynchronous private key operation.
    RetryAllOperations();
  }
  
  int SSLClientSocketImpl::TokenBindingAdd(const uint8_t** out,
                                           size_t* out_len,
                                           int* out_alert_value) {
    if (ssl_config_.token_binding_params.empty()) {
      return 0;
    }
    bssl::ScopedCBB output;
    CBB parameters_list;
    if (!CBB_init(output.get(), 7) ||
        !CBB_add_u8(output.get(), kTbProtocolVersionMajor) ||
        !CBB_add_u8(output.get(), kTbProtocolVersionMinor) ||
        !CBB_add_u8_length_prefixed(output.get(), &parameters_list)) {
      *out_alert_value = SSL_AD_INTERNAL_ERROR;
      return -1;
    }
    for (size_t i = 0; i < ssl_config_.token_binding_params.size(); ++i) {
      if (!CBB_add_u8(&parameters_list, ssl_config_.token_binding_params[i])) {
        *out_alert_value = SSL_AD_INTERNAL_ERROR;
        return -1;
      }
    }
    // |*out| will be freed by TokenBindingFreeCallback.
    if (!CBB_finish(output.get(), const_cast<uint8_t**>(out), out_len)) {
      *out_alert_value = SSL_AD_INTERNAL_ERROR;
      return -1;
    }
  
    return 1;
  }
  
  int SSLClientSocketImpl::TokenBindingParse(const uint8_t* contents,
                                             size_t contents_len,
                                             int* out_alert_value) {
    if (completed_connect_) {
      // Token Binding may only be negotiated on the initial handshake.
      *out_alert_value = SSL_AD_ILLEGAL_PARAMETER;
      return 0;
    }
  
    CBS extension;
    CBS_init(&extension, contents, contents_len);
  
    CBS parameters_list;
    uint8_t version_major, version_minor, param;
    if (!CBS_get_u8(&extension, &version_major) ||
        !CBS_get_u8(&extension, &version_minor) ||
        !CBS_get_u8_length_prefixed(&extension, &parameters_list) ||
        !CBS_get_u8(&parameters_list, &param) || CBS_len(&parameters_list) > 0 ||
        CBS_len(&extension) > 0) {
      *out_alert_value = SSL_AD_DECODE_ERROR;
      return 0;
    }
    // The server-negotiated version must be less than or equal to our version.
    if (version_major > kTbProtocolVersionMajor ||
        (version_minor > kTbProtocolVersionMinor &&
         version_major == kTbProtocolVersionMajor)) {
      *out_alert_value = SSL_AD_ILLEGAL_PARAMETER;
      return 0;
    }
    // If the version the server negotiated is older than we support, don't fail
    // parsing the extension, but also don't set |negotiated_|.
    if (version_major < kTbMinProtocolVersionMajor ||
        (version_minor < kTbMinProtocolVersionMinor &&
         version_major == kTbMinProtocolVersionMajor)) {
      return 1;
    }
  
    for (size_t i = 0; i < ssl_config_.token_binding_params.size(); ++i) {
      if (param == ssl_config_.token_binding_params[i]) {
        tb_negotiated_param_ = ssl_config_.token_binding_params[i];
        tb_was_negotiated_ = true;
        return 1;
      }
    }
  
    *out_alert_value = SSL_AD_ILLEGAL_PARAMETER;
    return 0;
  }
  
  void SSLClientSocketImpl::LogConnectEndEvent(int rv) {
    if (rv != OK) {
      net_log_.EndEventWithNetErrorCode(NetLogEventType::SSL_CONNECT, rv);
      return;
    }
  
    net_log_.EndEvent(NetLogEventType::SSL_CONNECT,
                      base::Bind(&NetLogSSLInfoCallback, base::Unretained(this)));
  }
  
  void SSLClientSocketImpl::RecordNegotiatedProtocol() const {
    UMA_HISTOGRAM_ENUMERATION("Net.SSLNegotiatedAlpnProtocol",
                              negotiated_protocol_, kProtoLast + 1);
  }
  
  void SSLClientSocketImpl::RecordChannelIDSupport() const {
    // Since this enum is used for a histogram, do not change or re-use values.
    enum {
      DISABLED = 0,
      CLIENT_ONLY = 1,
      CLIENT_AND_SERVER = 2,
      // CLIENT_NO_ECC is unused now.
      // CLIENT_BAD_SYSTEM_TIME is unused now.
      CLIENT_BAD_SYSTEM_TIME = 4,
      CLIENT_NO_CHANNEL_ID_SERVICE = 5,
      CHANNEL_ID_USAGE_MAX
    } supported = DISABLED;
    if (channel_id_sent_) {
      supported = CLIENT_AND_SERVER;
    } else if (ssl_config_.channel_id_enabled) {
      if (!channel_id_service_)
        supported = CLIENT_NO_CHANNEL_ID_SERVICE;
      else
        supported = CLIENT_ONLY;
    }
    UMA_HISTOGRAM_ENUMERATION("DomainBoundCerts.Support", supported,
                              CHANNEL_ID_USAGE_MAX);
  }
  
  bool SSLClientSocketImpl::IsChannelIDEnabled() const {
    return ssl_config_.channel_id_enabled && channel_id_service_;
  }
  
  int SSLClientSocketImpl::MapLastOpenSSLError(
      int ssl_error,
      const crypto::OpenSSLErrStackTracer& tracer,
      OpenSSLErrorInfo* info) {
    int net_error = MapOpenSSLErrorWithDetails(ssl_error, tracer, info);
  
    if (ssl_error == SSL_ERROR_SSL &&
        ERR_GET_LIB(info->error_code) == ERR_LIB_SSL) {
      // TLS does not provide an alert for missing client certificates, so most
      // servers send a generic handshake_failure alert. Detect this case by
      // checking if we have received a CertificateRequest but sent no
      // certificate. See https://crbug.com/646567.
      if (ERR_GET_REASON(info->error_code) ==
              SSL_R_SSLV3_ALERT_HANDSHAKE_FAILURE &&
          certificate_requested_ && ssl_config_.send_client_cert &&
          !ssl_config_.client_cert) {
        net_error = ERR_BAD_SSL_CLIENT_AUTH_CERT;
      }
  
      // Per spec, access_denied is only for client-certificate-based access
      // control, but some buggy firewalls use it when blocking a page. To avoid a
      // confusing error, map it to a generic protocol error if no
      // CertificateRequest was sent. See https://crbug.com/630883.
      if (ERR_GET_REASON(info->error_code) == SSL_R_TLSV1_ALERT_ACCESS_DENIED &&
          !certificate_requested_) {
        net_error = ERR_SSL_PROTOCOL_ERROR;
      }
    }
  
    return net_error;
  }
  
  }  // namespace net
  