text: /* Copyright (c) 2014, Google Inc.
   *
   * Permission to use, copy, modify, and/or distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
   * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
   * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
   * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
  
  #if !defined(__STDC_FORMAT_MACROS)
  #define __STDC_FORMAT_MACROS
  #endif
  
  #include <openssl/base.h>
  
  #if !defined(OPENSSL_WINDOWS)
  #include <arpa/inet.h>
  #include <netinet/in.h>
  #include <netinet/tcp.h>
  #include <signal.h>
  #include <sys/socket.h>
  #include <sys/time.h>
  #include <unistd.h>
  #else
  #include <io.h>
  OPENSSL_MSVC_PRAGMA(warning(push, 3))
  #include <winsock2.h>
  #include <ws2tcpip.h>
  OPENSSL_MSVC_PRAGMA(warning(pop))
  
  OPENSSL_MSVC_PRAGMA(comment(lib, "Ws2_32.lib"))
  #endif
  
  #include <assert.h>
  #include <inttypes.h>
  #include <string.h>
  
  #include <openssl/aead.h>
  #include <openssl/bio.h>
  #include <openssl/buf.h>
  #include <openssl/bytestring.h>
  #include <openssl/cipher.h>
  #include <openssl/crypto.h>
  #include <openssl/dh.h>
  #include <openssl/digest.h>
  #include <openssl/err.h>
  #include <openssl/evp.h>
  #include <openssl/hmac.h>
  #include <openssl/nid.h>
  #include <openssl/rand.h>
  #include <openssl/ssl.h>
  #include <openssl/x509.h>
  
  #include <memory>
  #include <string>
  #include <vector>
  
  #include "../../crypto/internal.h"
  #include "async_bio.h"
  #include "packeted_bio.h"
  #include "test_config.h"
  
  
  static CRYPTO_BUFFER_POOL *g_pool = nullptr;
  
  #if !defined(OPENSSL_WINDOWS)
  static int closesocket(int sock) {
    return close(sock);
  }
  
  static void PrintSocketError(const char *func) {
    perror(func);
  }
  #else
  static void PrintSocketError(const char *func) {
    fprintf(stderr, "%s: %d\n", func, WSAGetLastError());
  }
  #endif
  
  static int Usage(const char *program) {
    fprintf(stderr, "Usage: %s [flags...]\n", program);
    return 1;
  }
  
  struct TestState {
    // async_bio is async BIO which pauses reads and writes.
    BIO *async_bio = nullptr;
    // packeted_bio is the packeted BIO which simulates read timeouts.
    BIO *packeted_bio = nullptr;
    bssl::UniquePtr<EVP_PKEY> channel_id;
    bool cert_ready = false;
    bssl::UniquePtr<SSL_SESSION> session;
    bssl::UniquePtr<SSL_SESSION> pending_session;
    bool early_callback_called = false;
    bool handshake_done = false;
    // private_key is the underlying private key used when testing custom keys.
    bssl::UniquePtr<EVP_PKEY> private_key;
    std::vector<uint8_t> private_key_result;
    // private_key_retries is the number of times an asynchronous private key
    // operation has been retried.
    unsigned private_key_retries = 0;
    bool got_new_session = false;
    bssl::UniquePtr<SSL_SESSION> new_session;
    bool ticket_decrypt_done = false;
    bool alpn_select_done = false;
  };
  
  static void TestStateExFree(void *parent, void *ptr, CRYPTO_EX_DATA *ad,
                              int index, long argl, void *argp) {
    delete ((TestState *)ptr);
  }
  
  static int g_config_index = 0;
  static int g_state_index = 0;
  
  static bool SetTestConfig(SSL *ssl, const TestConfig *config) {
    return SSL_set_ex_data(ssl, g_config_index, (void *)config) == 1;
  }
  
  static const TestConfig *GetTestConfig(const SSL *ssl) {
    return (const TestConfig *)SSL_get_ex_data(ssl, g_config_index);
  }
  
  static bool SetTestState(SSL *ssl, std::unique_ptr<TestState> state) {
    // |SSL_set_ex_data| takes ownership of |state| only on success.
    if (SSL_set_ex_data(ssl, g_state_index, state.get()) == 1) {
      state.release();
      return true;
    }
    return false;
  }
  
  static TestState *GetTestState(const SSL *ssl) {
    return (TestState *)SSL_get_ex_data(ssl, g_state_index);
  }
  
  static bool LoadCertificate(bssl::UniquePtr<X509> *out_x509,
                              bssl::UniquePtr<STACK_OF(X509)> *out_chain,
                              const std::string &file) {
    bssl::UniquePtr<BIO> bio(BIO_new(BIO_s_file()));
    if (!bio || !BIO_read_filename(bio.get(), file.c_str())) {
      return false;
    }
  
    out_x509->reset(PEM_read_bio_X509(bio.get(), nullptr, nullptr, nullptr));
    if (!*out_x509) {
      return false;
    }
  
    out_chain->reset(sk_X509_new_null());
    if (!*out_chain) {
      return false;
    }
  
    // Keep reading the certificate chain.
    for (;;) {
      bssl::UniquePtr<X509> cert(
          PEM_read_bio_X509(bio.get(), nullptr, nullptr, nullptr));
      if (!cert) {
        break;
      }
  
      if (!sk_X509_push(out_chain->get(), cert.get())) {
        return false;
      }
      cert.release();  // sk_X509_push takes ownership.
    }
  
    uint32_t err = ERR_peek_last_error();
    if (ERR_GET_LIB(err) != ERR_LIB_PEM ||
        ERR_GET_REASON(err) != PEM_R_NO_START_LINE) {
      return false;
  }
  
    ERR_clear_error();
    return true;
  }
  
  static bssl::UniquePtr<EVP_PKEY> LoadPrivateKey(const std::string &file) {
    bssl::UniquePtr<BIO> bio(BIO_new(BIO_s_file()));
    if (!bio || !BIO_read_filename(bio.get(), file.c_str())) {
      return nullptr;
    }
    return bssl::UniquePtr<EVP_PKEY>(
        PEM_read_bio_PrivateKey(bio.get(), NULL, NULL, NULL));
  }
  
  static int AsyncPrivateKeyType(SSL *ssl) {
    EVP_PKEY *key = GetTestState(ssl)->private_key.get();
    switch (EVP_PKEY_id(key)) {
      case EVP_PKEY_RSA:
        return NID_rsaEncryption;
      case EVP_PKEY_EC:
        return EC_GROUP_get_curve_name(
            EC_KEY_get0_group(EVP_PKEY_get0_EC_KEY(key)));
      default:
        return NID_undef;
    }
  }
  
  static size_t AsyncPrivateKeyMaxSignatureLen(SSL *ssl) {
    return EVP_PKEY_size(GetTestState(ssl)->private_key.get());
  }
  
  static ssl_private_key_result_t AsyncPrivateKeySign(
      SSL *ssl, uint8_t *out, size_t *out_len, size_t max_out,
      uint16_t signature_algorithm, const uint8_t *in, size_t in_len) {
    TestState *test_state = GetTestState(ssl);
    if (!test_state->private_key_result.empty()) {
      fprintf(stderr, "AsyncPrivateKeySign called with operation pending.\n");
      abort();
    }
  
    // Determine the hash.
    const EVP_MD *md;
    switch (signature_algorithm) {
      case SSL_SIGN_RSA_PKCS1_SHA1:
      case SSL_SIGN_ECDSA_SHA1:
        md = EVP_sha1();
        break;
      case SSL_SIGN_RSA_PKCS1_SHA256:
      case SSL_SIGN_ECDSA_SECP256R1_SHA256:
      case SSL_SIGN_RSA_PSS_SHA256:
        md = EVP_sha256();
        break;
      case SSL_SIGN_RSA_PKCS1_SHA384:
      case SSL_SIGN_ECDSA_SECP384R1_SHA384:
      case SSL_SIGN_RSA_PSS_SHA384:
        md = EVP_sha384();
        break;
      case SSL_SIGN_RSA_PKCS1_SHA512:
      case SSL_SIGN_ECDSA_SECP521R1_SHA512:
      case SSL_SIGN_RSA_PSS_SHA512:
        md = EVP_sha512();
        break;
      case SSL_SIGN_RSA_PKCS1_MD5_SHA1:
        md = EVP_md5_sha1();
        break;
      default:
        fprintf(stderr, "Unknown signature algorithm %04x.\n",
                signature_algorithm);
        return ssl_private_key_failure;
    }
  
    bssl::ScopedEVP_MD_CTX ctx;
    EVP_PKEY_CTX *pctx;
    if (!EVP_DigestSignInit(ctx.get(), &pctx, md, nullptr,
                            test_state->private_key.get())) {
      return ssl_private_key_failure;
    }
  
    // Configure additional signature parameters.
    switch (signature_algorithm) {
      case SSL_SIGN_RSA_PSS_SHA256:
      case SSL_SIGN_RSA_PSS_SHA384:
      case SSL_SIGN_RSA_PSS_SHA512:
        if (!EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING) ||
            !EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx,
                                              -1 /* salt len = hash len */)) {
          return ssl_private_key_failure;
        }
    }
  
    // Write the signature into |test_state|.
    size_t len = 0;
    if (!EVP_DigestSignUpdate(ctx.get(), in, in_len) ||
        !EVP_DigestSignFinal(ctx.get(), nullptr, &len)) {
      return ssl_private_key_failure;
    }
    test_state->private_key_result.resize(len);
    if (!EVP_DigestSignFinal(ctx.get(), test_state->private_key_result.data(),
                             &len)) {
      return ssl_private_key_failure;
    }
    test_state->private_key_result.resize(len);
  
    // The signature will be released asynchronously in |AsyncPrivateKeyComplete|.
    return ssl_private_key_retry;
  }
  
  static ssl_private_key_result_t AsyncPrivateKeyDecrypt(
      SSL *ssl, uint8_t *out, size_t *out_len, size_t max_out,
      const uint8_t *in, size_t in_len) {
    TestState *test_state = GetTestState(ssl);
    if (!test_state->private_key_result.empty()) {
      fprintf(stderr,
              "AsyncPrivateKeyDecrypt called with operation pending.\n");
      abort();
    }
  
    RSA *rsa = EVP_PKEY_get0_RSA(test_state->private_key.get());
    if (rsa == NULL) {
      fprintf(stderr,
              "AsyncPrivateKeyDecrypt called with incorrect key type.\n");
      abort();
    }
    test_state->private_key_result.resize(RSA_size(rsa));
    if (!RSA_decrypt(rsa, out_len, test_state->private_key_result.data(),
                     RSA_size(rsa), in, in_len, RSA_NO_PADDING)) {
      return ssl_private_key_failure;
    }
  
    test_state->private_key_result.resize(*out_len);
  
    // The decryption will be released asynchronously in |AsyncPrivateComplete|.
    return ssl_private_key_retry;
  }
  
  static ssl_private_key_result_t AsyncPrivateKeyComplete(
      SSL *ssl, uint8_t *out, size_t *out_len, size_t max_out) {
    TestState *test_state = GetTestState(ssl);
    if (test_state->private_key_result.empty()) {
      fprintf(stderr,
              "AsyncPrivateKeyComplete called without operation pending.\n");
      abort();
    }
  
    if (test_state->private_key_retries < 2) {
      // Only return the decryption on the second attempt, to test both incomplete
      // |decrypt| and |decrypt_complete|.
      return ssl_private_key_retry;
    }
  
    if (max_out < test_state->private_key_result.size()) {
      fprintf(stderr, "Output buffer too small.\n");
      return ssl_private_key_failure;
    }
    OPENSSL_memcpy(out, test_state->private_key_result.data(),
                   test_state->private_key_result.size());
    *out_len = test_state->private_key_result.size();
  
    test_state->private_key_result.clear();
    test_state->private_key_retries = 0;
    return ssl_private_key_success;
  }
  
  static const SSL_PRIVATE_KEY_METHOD g_async_private_key_method = {
      AsyncPrivateKeyType,
      AsyncPrivateKeyMaxSignatureLen,
      AsyncPrivateKeySign,
      nullptr /* sign_digest */,
      AsyncPrivateKeyDecrypt,
      AsyncPrivateKeyComplete,
  };
  
  template<typename T>
  struct Free {
    void operator()(T *buf) {
      free(buf);
    }
  };
  
  static bool GetCertificate(SSL *ssl, bssl::UniquePtr<X509> *out_x509,
                             bssl::UniquePtr<STACK_OF(X509)> *out_chain,
                             bssl::UniquePtr<EVP_PKEY> *out_pkey) {
    const TestConfig *config = GetTestConfig(ssl);
  
    if (!config->digest_prefs.empty()) {
      std::unique_ptr<char, Free<char>> digest_prefs(
          strdup(config->digest_prefs.c_str()));
      std::vector<int> digest_list;
  
      for (;;) {
        char *token =
            strtok(digest_list.empty() ? digest_prefs.get() : nullptr, ",");
        if (token == nullptr) {
          break;
        }
  
        digest_list.push_back(EVP_MD_type(EVP_get_digestbyname(token)));
      }
  
      if (!SSL_set_private_key_digest_prefs(ssl, digest_list.data(),
                                            digest_list.size())) {
        return false;
      }
    }
  
    if (!config->signing_prefs.empty()) {
      std::vector<uint16_t> u16s(config->signing_prefs.begin(),
                                 config->signing_prefs.end());
      if (!SSL_set_signing_algorithm_prefs(ssl, u16s.data(), u16s.size())) {
        return false;
      }
    }
  
    if (!config->key_file.empty()) {
      *out_pkey = LoadPrivateKey(config->key_file.c_str());
      if (!*out_pkey) {
        return false;
      }
    }
    if (!config->cert_file.empty() &&
        !LoadCertificate(out_x509, out_chain, config->cert_file.c_str())) {
      return false;
    }
    if (!config->ocsp_response.empty() &&
        !SSL_set_ocsp_response(ssl, (const uint8_t *)config->ocsp_response.data(),
                               config->ocsp_response.size())) {
      return false;
    }
    return true;
  }
  
  static bool InstallCertificate(SSL *ssl) {
    bssl::UniquePtr<X509> x509;
    bssl::UniquePtr<STACK_OF(X509)> chain;
    bssl::UniquePtr<EVP_PKEY> pkey;
    if (!GetCertificate(ssl, &x509, &chain, &pkey)) {
      return false;
    }
  
    if (pkey) {
      TestState *test_state = GetTestState(ssl);
      const TestConfig *config = GetTestConfig(ssl);
      if (config->async) {
        test_state->private_key = std::move(pkey);
        SSL_set_private_key_method(ssl, &g_async_private_key_method);
      } else if (!SSL_use_PrivateKey(ssl, pkey.get())) {
        return false;
      }
    }
  
    if (x509 && !SSL_use_certificate(ssl, x509.get())) {
      return false;
    }
  
    if (sk_X509_num(chain.get()) > 0 &&
        !SSL_set1_chain(ssl, chain.get())) {
      return false;
    }
  
    return true;
  }
  
  static int SelectCertificateCallback(const SSL_CLIENT_HELLO *client_hello) {
    const TestConfig *config = GetTestConfig(client_hello->ssl);
    GetTestState(client_hello->ssl)->early_callback_called = true;
  
    if (!config->expected_server_name.empty()) {
      const uint8_t *extension_data;
      size_t extension_len;
      CBS extension, server_name_list, host_name;
      uint8_t name_type;
  
      if (!SSL_early_callback_ctx_extension_get(
              client_hello, TLSEXT_TYPE_server_name, &extension_data,
              &extension_len)) {
        fprintf(stderr, "Could not find server_name extension.\n");
        return -1;
      }
  
      CBS_init(&extension, extension_data, extension_len);
      if (!CBS_get_u16_length_prefixed(&extension, &server_name_list) ||
          CBS_len(&extension) != 0 ||
          !CBS_get_u8(&server_name_list, &name_type) ||
          name_type != TLSEXT_NAMETYPE_host_name ||
          !CBS_get_u16_length_prefixed(&server_name_list, &host_name) ||
          CBS_len(&server_name_list) != 0) {
        fprintf(stderr, "Could not decode server_name extension.\n");
        return -1;
      }
  
      if (!CBS_mem_equal(&host_name,
                         (const uint8_t*)config->expected_server_name.data(),
                         config->expected_server_name.size())) {
        fprintf(stderr, "Server name mismatch.\n");
      }
    }
  
    if (config->fail_early_callback) {
      return -1;
    }
  
    // Install the certificate in the early callback.
    if (config->use_early_callback) {
      if (config->async) {
        // Install the certificate asynchronously.
        return 0;
      }
      if (!InstallCertificate(client_hello->ssl)) {
        return -1;
      }
    }
    return 1;
  }
  
  static bool CheckCertificateRequest(SSL *ssl) {
    const TestConfig *config = GetTestConfig(ssl);
  
    if (!config->expected_certificate_types.empty()) {
      const uint8_t *certificate_types;
      size_t certificate_types_len =
          SSL_get0_certificate_types(ssl, &certificate_types);
      if (certificate_types_len != config->expected_certificate_types.size() ||
          OPENSSL_memcmp(certificate_types,
                         config->expected_certificate_types.data(),
                         certificate_types_len) != 0) {
        fprintf(stderr, "certificate types mismatch\n");
        return false;
      }
    }
  
    // TODO(davidben): Test |SSL_get_client_CA_list|.
    return true;
  }
  
  static int ClientCertCallback(SSL *ssl, X509 **out_x509, EVP_PKEY **out_pkey) {
    if (!CheckCertificateRequest(ssl)) {
      return -1;
    }
  
    if (GetTestConfig(ssl)->async && !GetTestState(ssl)->cert_ready) {
      return -1;
    }
  
    bssl::UniquePtr<X509> x509;
    bssl::UniquePtr<STACK_OF(X509)> chain;
    bssl::UniquePtr<EVP_PKEY> pkey;
    if (!GetCertificate(ssl, &x509, &chain, &pkey)) {
      return -1;
    }
  
    // Return zero for no certificate.
    if (!x509) {
      return 0;
    }
  
    // Chains and asynchronous private keys are not supported with client_cert_cb.
    *out_x509 = x509.release();
    *out_pkey = pkey.release();
    return 1;
  }
  
  static int CertCallback(SSL *ssl, void *arg) {
    const TestConfig *config = GetTestConfig(ssl);
  
    // Check the CertificateRequest metadata is as expected.
    if (!SSL_is_server(ssl) && !CheckCertificateRequest(ssl)) {
      return -1;
    }
  
    if (config->fail_cert_callback) {
      return 0;
    }
  
    // The certificate will be installed via other means.
    if (!config->async || config->use_early_callback) {
      return 1;
    }
  
    if (!GetTestState(ssl)->cert_ready) {
      return -1;
    }
    if (!InstallCertificate(ssl)) {
      return 0;
    }
    return 1;
  }
  
  static int VerifySucceed(X509_STORE_CTX *store_ctx, void *arg) {
    SSL* ssl = (SSL*)X509_STORE_CTX_get_ex_data(store_ctx,
        SSL_get_ex_data_X509_STORE_CTX_idx());
    const TestConfig *config = GetTestConfig(ssl);
  
    if (!config->expected_ocsp_response.empty()) {
      const uint8_t *data;
      size_t len;
      SSL_get0_ocsp_response(ssl, &data, &len);
      if (len == 0) {
        fprintf(stderr, "OCSP response not available in verify callback\n");
        return 0;
      }
    }
  
    return 1;
  }
  
  static int VerifyFail(X509_STORE_CTX *store_ctx, void *arg) {
    store_ctx->error = X509_V_ERR_APPLICATION_VERIFICATION;
    return 0;
  }
  
  static int NextProtosAdvertisedCallback(SSL *ssl, const uint8_t **out,
                                          unsigned int *out_len, void *arg) {
    const TestConfig *config = GetTestConfig(ssl);
    if (config->advertise_npn.empty()) {
      return SSL_TLSEXT_ERR_NOACK;
    }
  
    *out = (const uint8_t*)config->advertise_npn.data();
    *out_len = config->advertise_npn.size();
    return SSL_TLSEXT_ERR_OK;
  }
  
  static int NextProtoSelectCallback(SSL* ssl, uint8_t** out, uint8_t* outlen,
                                     const uint8_t* in, unsigned inlen, void* arg) {
    const TestConfig *config = GetTestConfig(ssl);
    if (config->select_next_proto.empty()) {
      return SSL_TLSEXT_ERR_NOACK;
    }
  
    *out = (uint8_t*)config->select_next_proto.data();
    *outlen = config->select_next_proto.size();
    return SSL_TLSEXT_ERR_OK;
  }
  
  static int AlpnSelectCallback(SSL* ssl, const uint8_t** out, uint8_t* outlen,
                                const uint8_t* in, unsigned inlen, void* arg) {
    if (GetTestState(ssl)->alpn_select_done) {
      fprintf(stderr, "AlpnSelectCallback called after completion.\n");
      exit(1);
    }
  
    GetTestState(ssl)->alpn_select_done = true;
  
    const TestConfig *config = GetTestConfig(ssl);
    if (config->decline_alpn) {
      return SSL_TLSEXT_ERR_NOACK;
    }
  
    if (!config->expected_advertised_alpn.empty() &&
        (config->expected_advertised_alpn.size() != inlen ||
         OPENSSL_memcmp(config->expected_advertised_alpn.data(), in, inlen) !=
             0)) {
      fprintf(stderr, "bad ALPN select callback inputs\n");
      exit(1);
    }
  
    *out = (const uint8_t*)config->select_alpn.data();
    *outlen = config->select_alpn.size();
    return SSL_TLSEXT_ERR_OK;
  }
  
  static unsigned PskClientCallback(SSL *ssl, const char *hint,
                                    char *out_identity,
                                    unsigned max_identity_len,
                                    uint8_t *out_psk, unsigned max_psk_len) {
    const TestConfig *config = GetTestConfig(ssl);
  
    if (config->psk_identity.empty()) {
      if (hint != nullptr) {
        fprintf(stderr, "Server PSK hint was non-null.\n");
        return 0;
      }
    } else if (hint == nullptr ||
               strcmp(hint, config->psk_identity.c_str()) != 0) {
      fprintf(stderr, "Server PSK hint did not match.\n");
      return 0;
    }
  
    // Account for the trailing '\0' for the identity.
    if (config->psk_identity.size() >= max_identity_len ||
        config->psk.size() > max_psk_len) {
      fprintf(stderr, "PSK buffers too small\n");
      return 0;
    }
  
    BUF_strlcpy(out_identity, config->psk_identity.c_str(),
                max_identity_len);
    OPENSSL_memcpy(out_psk, config->psk.data(), config->psk.size());
    return config->psk.size();
  }
  
  static unsigned PskServerCallback(SSL *ssl, const char *identity,
                                    uint8_t *out_psk, unsigned max_psk_len) {
    const TestConfig *config = GetTestConfig(ssl);
  
    if (strcmp(identity, config->psk_identity.c_str()) != 0) {
      fprintf(stderr, "Client PSK identity did not match.\n");
      return 0;
    }
  
    if (config->psk.size() > max_psk_len) {
      fprintf(stderr, "PSK buffers too small\n");
      return 0;
    }
  
    OPENSSL_memcpy(out_psk, config->psk.data(), config->psk.size());
    return config->psk.size();
  }
  
  static timeval g_clock;
  
  static void CurrentTimeCallback(const SSL *ssl, timeval *out_clock) {
    *out_clock = g_clock;
  }
  
  static void ChannelIdCallback(SSL *ssl, EVP_PKEY **out_pkey) {
    *out_pkey = GetTestState(ssl)->channel_id.release();
  }
  
  static SSL_SESSION *GetSessionCallback(SSL *ssl, uint8_t *data, int len,
                                         int *copy) {
    TestState *async_state = GetTestState(ssl);
    if (async_state->session) {
      *copy = 0;
      return async_state->session.release();
    } else if (async_state->pending_session) {
      return SSL_magic_pending_session_ptr();
    } else {
      return NULL;
    }
  }
  
  static int DDoSCallback(const SSL_CLIENT_HELLO *client_hello) {
    const TestConfig *config = GetTestConfig(client_hello->ssl);
    static int callback_num = 0;
  
    callback_num++;
    if (config->fail_ddos_callback ||
        (config->fail_second_ddos_callback && callback_num == 2)) {
      return 0;
    }
    return 1;
  }
  
  static void InfoCallback(const SSL *ssl, int type, int val) {
    if (type == SSL_CB_HANDSHAKE_DONE) {
      if (GetTestConfig(ssl)->handshake_never_done) {
        fprintf(stderr, "Handshake unexpectedly completed.\n");
        // Abort before any expected error code is printed, to ensure the overall
        // test fails.
        abort();
      }
      GetTestState(ssl)->handshake_done = true;
  
      // Callbacks may be called again on a new handshake.
      GetTestState(ssl)->ticket_decrypt_done = false;
      GetTestState(ssl)->alpn_select_done = false;
    }
  }
  
  static int NewSessionCallback(SSL *ssl, SSL_SESSION *session) {
    GetTestState(ssl)->got_new_session = true;
    GetTestState(ssl)->new_session.reset(session);
    return 1;
  }
  
  static int TicketKeyCallback(SSL *ssl, uint8_t *key_name, uint8_t *iv,
                               EVP_CIPHER_CTX *ctx, HMAC_CTX *hmac_ctx,
                               int encrypt) {
    if (!encrypt) {
      if (GetTestState(ssl)->ticket_decrypt_done) {
        fprintf(stderr, "TicketKeyCallback called after completion.\n");
        return -1;
      }
  
      GetTestState(ssl)->ticket_decrypt_done = true;
    }
  
    // This is just test code, so use the all-zeros key.
    static const uint8_t kZeros[16] = {0};
  
    if (encrypt) {
      OPENSSL_memcpy(key_name, kZeros, sizeof(kZeros));
      RAND_bytes(iv, 16);
    } else if (OPENSSL_memcmp(key_name, kZeros, 16) != 0) {
      return 0;
    }
  
    if (!HMAC_Init_ex(hmac_ctx, kZeros, sizeof(kZeros), EVP_sha256(), NULL) ||
        !EVP_CipherInit_ex(ctx, EVP_aes_128_cbc(), NULL, kZeros, iv, encrypt)) {
      return -1;
    }
  
    if (!encrypt) {
      return GetTestConfig(ssl)->renew_ticket ? 2 : 1;
    }
    return 1;
  }
  
  // kCustomExtensionValue is the extension value that the custom extension
  // callbacks will add.
  static const uint16_t kCustomExtensionValue = 1234;
  static void *const kCustomExtensionAddArg =
      reinterpret_cast<void *>(kCustomExtensionValue);
  static void *const kCustomExtensionParseArg =
      reinterpret_cast<void *>(kCustomExtensionValue + 1);
  static const char kCustomExtensionContents[] = "custom extension";
  
  static int CustomExtensionAddCallback(SSL *ssl, unsigned extension_value,
                                        const uint8_t **out, size_t *out_len,
                                        int *out_alert_value, void *add_arg) {
    if (extension_value != kCustomExtensionValue ||
        add_arg != kCustomExtensionAddArg) {
      abort();
    }
  
    if (GetTestConfig(ssl)->custom_extension_skip) {
      return 0;
    }
    if (GetTestConfig(ssl)->custom_extension_fail_add) {
      return -1;
    }
  
    *out = reinterpret_cast<const uint8_t*>(kCustomExtensionContents);
    *out_len = sizeof(kCustomExtensionContents) - 1;
  
    return 1;
  }
  
  static void CustomExtensionFreeCallback(SSL *ssl, unsigned extension_value,
                                          const uint8_t *out, void *add_arg) {
    if (extension_value != kCustomExtensionValue ||
        add_arg != kCustomExtensionAddArg ||
        out != reinterpret_cast<const uint8_t *>(kCustomExtensionContents)) {
      abort();
    }
  }
  
  static int CustomExtensionParseCallback(SSL *ssl, unsigned extension_value,
                                          const uint8_t *contents,
                                          size_t contents_len,
                                          int *out_alert_value, void *parse_arg) {
    if (extension_value != kCustomExtensionValue ||
        parse_arg != kCustomExtensionParseArg) {
      abort();
    }
  
    if (contents_len != sizeof(kCustomExtensionContents) - 1 ||
        OPENSSL_memcmp(contents, kCustomExtensionContents, contents_len) != 0) {
      *out_alert_value = SSL_AD_DECODE_ERROR;
      return 0;
    }
  
    return 1;
  }
  
  static int ServerNameCallback(SSL *ssl, int *out_alert, void *arg) {
    // SNI must be accessible from the SNI callback.
    const TestConfig *config = GetTestConfig(ssl);
    const char *server_name = SSL_get_servername(ssl, TLSEXT_NAMETYPE_host_name);
    if (server_name == nullptr ||
        std::string(server_name) != config->expected_server_name) {
      fprintf(stderr, "servername mismatch (got %s; want %s)\n", server_name,
              config->expected_server_name.c_str());
      return SSL_TLSEXT_ERR_ALERT_FATAL;
    }
  
    return SSL_TLSEXT_ERR_OK;
  }
  
  // Connect returns a new socket connected to localhost on |port| or -1 on
  // error.
  static int Connect(uint16_t port) {
    int sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock == -1) {
      PrintSocketError("socket");
      return -1;
    }
    int nodelay = 1;
    if (setsockopt(sock, IPPROTO_TCP, TCP_NODELAY,
            reinterpret_cast<const char*>(&nodelay), sizeof(nodelay)) != 0) {
      PrintSocketError("setsockopt");
      closesocket(sock);
      return -1;
    }
    sockaddr_in sin;
    OPENSSL_memset(&sin, 0, sizeof(sin));
    sin.sin_family = AF_INET;
    sin.sin_port = htons(port);
    if (!inet_pton(AF_INET, "127.0.0.1", &sin.sin_addr)) {
      PrintSocketError("inet_pton");
      closesocket(sock);
      return -1;
    }
    if (connect(sock, reinterpret_cast<const sockaddr*>(&sin),
                sizeof(sin)) != 0) {
      PrintSocketError("connect");
      closesocket(sock);
      return -1;
    }
    return sock;
  }
  
  class SocketCloser {
   public:
    explicit SocketCloser(int sock) : sock_(sock) {}
    ~SocketCloser() {
      // Half-close and drain the socket before releasing it. This seems to be
      // necessary for graceful shutdown on Windows. It will also avoid write
      // failures in the test runner.
  #if defined(OPENSSL_WINDOWS)
      shutdown(sock_, SD_SEND);
  #else
      shutdown(sock_, SHUT_WR);
  #endif
      while (true) {
        char buf[1024];
        if (recv(sock_, buf, sizeof(buf), 0) <= 0) {
          break;
        }
      }
      closesocket(sock_);
    }
  
   private:
    const int sock_;
  };
  
  static bssl::UniquePtr<SSL_CTX> SetupCtx(const TestConfig *config) {
    bssl::UniquePtr<SSL_CTX> ssl_ctx(SSL_CTX_new(
        config->is_dtls ? DTLS_method() : TLS_method()));
    if (!ssl_ctx) {
      return nullptr;
    }
  
    SSL_CTX_set0_buffer_pool(ssl_ctx.get(), g_pool);
  
    // Enable TLS 1.3 for tests.
    if (!config->is_dtls &&
        !SSL_CTX_set_max_proto_version(ssl_ctx.get(), TLS1_3_VERSION)) {
      return nullptr;
    }
  
    std::string cipher_list = "ALL";
    if (!config->cipher.empty()) {
      cipher_list = config->cipher;
      SSL_CTX_set_options(ssl_ctx.get(), SSL_OP_CIPHER_SERVER_PREFERENCE);
    }
    if (!SSL_CTX_set_cipher_list(ssl_ctx.get(), cipher_list.c_str())) {
      return nullptr;
    }
  
    bssl::UniquePtr<DH> dh(DH_get_2048_256(NULL));
    if (!dh) {
      return nullptr;
    }
  
    if (config->use_sparse_dh_prime) {
      // This prime number is 2^1024 + 643 – a value just above a power of two.
      // Because of its form, values modulo it are essentially certain to be one
      // byte shorter. This is used to test padding of these values.
      if (BN_hex2bn(
              &dh->p,
              "1000000000000000000000000000000000000000000000000000000000000000"
              "0000000000000000000000000000000000000000000000000000000000000000"
              "0000000000000000000000000000000000000000000000000000000000000000"
              "0000000000000000000000000000000000000000000000000000000000000028"
              "3") == 0 ||
          !BN_set_word(dh->g, 2)) {
        return nullptr;
      }
      BN_free(dh->q);
      dh->q = NULL;
      dh->priv_length = 0;
    }
  
    if (!SSL_CTX_set_tmp_dh(ssl_ctx.get(), dh.get())) {
      return nullptr;
    }
  
    if (config->async && config->is_server) {
      // Disable the internal session cache. To test asynchronous session lookup,
      // we use an external session cache.
      SSL_CTX_set_session_cache_mode(
          ssl_ctx.get(), SSL_SESS_CACHE_BOTH | SSL_SESS_CACHE_NO_INTERNAL);
      SSL_CTX_sess_set_get_cb(ssl_ctx.get(), GetSessionCallback);
    } else {
      SSL_CTX_set_session_cache_mode(ssl_ctx.get(), SSL_SESS_CACHE_BOTH);
    }
  
    SSL_CTX_set_select_certificate_cb(ssl_ctx.get(), SelectCertificateCallback);
  
    if (config->use_old_client_cert_callback) {
      SSL_CTX_set_client_cert_cb(ssl_ctx.get(), ClientCertCallback);
    }
  
    SSL_CTX_set_next_protos_advertised_cb(
        ssl_ctx.get(), NextProtosAdvertisedCallback, NULL);
    if (!config->select_next_proto.empty()) {
      SSL_CTX_set_next_proto_select_cb(ssl_ctx.get(), NextProtoSelectCallback,
                                       NULL);
    }
  
    if (!config->select_alpn.empty() || config->decline_alpn) {
      SSL_CTX_set_alpn_select_cb(ssl_ctx.get(), AlpnSelectCallback, NULL);
    }
  
    SSL_CTX_set_channel_id_cb(ssl_ctx.get(), ChannelIdCallback);
  
    SSL_CTX_set_current_time_cb(ssl_ctx.get(), CurrentTimeCallback);
  
    SSL_CTX_set_info_callback(ssl_ctx.get(), InfoCallback);
    SSL_CTX_sess_set_new_cb(ssl_ctx.get(), NewSessionCallback);
  
    if (config->use_ticket_callback) {
      SSL_CTX_set_tlsext_ticket_key_cb(ssl_ctx.get(), TicketKeyCallback);
    }
  
    if (config->enable_client_custom_extension &&
        !SSL_CTX_add_client_custom_ext(
            ssl_ctx.get(), kCustomExtensionValue, CustomExtensionAddCallback,
            CustomExtensionFreeCallback, kCustomExtensionAddArg,
            CustomExtensionParseCallback, kCustomExtensionParseArg)) {
      return nullptr;
    }
  
    if (config->enable_server_custom_extension &&
        !SSL_CTX_add_server_custom_ext(
            ssl_ctx.get(), kCustomExtensionValue, CustomExtensionAddCallback,
            CustomExtensionFreeCallback, kCustomExtensionAddArg,
            CustomExtensionParseCallback, kCustomExtensionParseArg)) {
      return nullptr;
    }
  
    if (config->verify_fail) {
      SSL_CTX_set_cert_verify_callback(ssl_ctx.get(), VerifyFail, NULL);
    } else {
      SSL_CTX_set_cert_verify_callback(ssl_ctx.get(), VerifySucceed, NULL);
    }
  
    if (!config->signed_cert_timestamps.empty() &&
        !SSL_CTX_set_signed_cert_timestamp_list(
            ssl_ctx.get(), (const uint8_t *)config->signed_cert_timestamps.data(),
            config->signed_cert_timestamps.size())) {
      return nullptr;
    }
  
    if (config->use_null_client_ca_list) {
      SSL_CTX_set_client_CA_list(ssl_ctx.get(), nullptr);
    }
  
    if (config->enable_grease) {
      SSL_CTX_set_grease_enabled(ssl_ctx.get(), 1);
    }
  
    if (!config->expected_server_name.empty()) {
      SSL_CTX_set_tlsext_servername_callback(ssl_ctx.get(), ServerNameCallback);
    }
  
    if (!config->ticket_key.empty() &&
        !SSL_CTX_set_tlsext_ticket_keys(ssl_ctx.get(), config->ticket_key.data(),
                                        config->ticket_key.size())) {
      return nullptr;
    }
  
    if (config->enable_short_header) {
      SSL_CTX_set_short_header_enabled(ssl_ctx.get(), 1);
    }
  
    return ssl_ctx;
  }
  
  // RetryAsync is called after a failed operation on |ssl| with return code
  // |ret|. If the operation should be retried, it simulates one asynchronous
  // event and returns true. Otherwise it returns false.
  static bool RetryAsync(SSL *ssl, int ret) {
    // No error; don't retry.
    if (ret >= 0) {
      return false;
    }
  
    TestState *test_state = GetTestState(ssl);
    assert(GetTestConfig(ssl)->async);
  
    if (test_state->packeted_bio != nullptr &&
        PacketedBioAdvanceClock(test_state->packeted_bio)) {
      // The DTLS retransmit logic silently ignores write failures. So the test
      // may progress, allow writes through synchronously.
      AsyncBioEnforceWriteQuota(test_state->async_bio, false);
      int timeout_ret = DTLSv1_handle_timeout(ssl);
      AsyncBioEnforceWriteQuota(test_state->async_bio, true);
  
      if (timeout_ret < 0) {
        fprintf(stderr, "Error retransmitting.\n");
        return false;
      }
      return true;
    }
  
    // See if we needed to read or write more. If so, allow one byte through on
    // the appropriate end to maximally stress the state machine.
    switch (SSL_get_error(ssl, ret)) {
      case SSL_ERROR_WANT_READ:
        AsyncBioAllowRead(test_state->async_bio, 1);
        return true;
      case SSL_ERROR_WANT_WRITE:
        AsyncBioAllowWrite(test_state->async_bio, 1);
        return true;
      case SSL_ERROR_WANT_CHANNEL_ID_LOOKUP: {
        bssl::UniquePtr<EVP_PKEY> pkey =
            LoadPrivateKey(GetTestConfig(ssl)->send_channel_id);
        if (!pkey) {
          return false;
        }
        test_state->channel_id = std::move(pkey);
        return true;
      }
      case SSL_ERROR_WANT_X509_LOOKUP:
        test_state->cert_ready = true;
        return true;
      case SSL_ERROR_PENDING_SESSION:
        test_state->session = std::move(test_state->pending_session);
        return true;
      case SSL_ERROR_PENDING_CERTIFICATE:
        // The handshake will resume without a second call to the early callback.
        return InstallCertificate(ssl);
      case SSL_ERROR_WANT_PRIVATE_KEY_OPERATION:
        test_state->private_key_retries++;
        return true;
      default:
        return false;
    }
  }
  
  // DoRead reads from |ssl|, resolving any asynchronous operations. It returns
  // the result value of the final |SSL_read| call.
  static int DoRead(SSL *ssl, uint8_t *out, size_t max_out) {
    const TestConfig *config = GetTestConfig(ssl);
    TestState *test_state = GetTestState(ssl);
    int ret;
    do {
      if (config->async) {
        // The DTLS retransmit logic silently ignores write failures. So the test
        // may progress, allow writes through synchronously. |SSL_read| may
        // trigger a retransmit, so disconnect the write quota.
        AsyncBioEnforceWriteQuota(test_state->async_bio, false);
      }
      ret = config->peek_then_read ? SSL_peek(ssl, out, max_out)
                                   : SSL_read(ssl, out, max_out);
      if (config->async) {
        AsyncBioEnforceWriteQuota(test_state->async_bio, true);
      }
  
      // Run the exporter after each read. This is to test that the exporter fails
      // during a renegotiation.
      if (config->use_exporter_between_reads) {
        uint8_t buf;
        if (!SSL_export_keying_material(ssl, &buf, 1, NULL, 0, NULL, 0, 0)) {
          fprintf(stderr, "failed to export keying material\n");
          return -1;
        }
      }
    } while (config->async && RetryAsync(ssl, ret));
  
    if (config->peek_then_read && ret > 0) {
      std::unique_ptr<uint8_t[]> buf(new uint8_t[static_cast<size_t>(ret)]);
  
      // SSL_peek should synchronously return the same data.
      int ret2 = SSL_peek(ssl, buf.get(), ret);
      if (ret2 != ret ||
          OPENSSL_memcmp(buf.get(), out, ret) != 0) {
        fprintf(stderr, "First and second SSL_peek did not match.\n");
        return -1;
      }
  
      // SSL_read should synchronously return the same data and consume it.
      ret2 = SSL_read(ssl, buf.get(), ret);
      if (ret2 != ret ||
          OPENSSL_memcmp(buf.get(), out, ret) != 0) {
        fprintf(stderr, "SSL_peek and SSL_read did not match.\n");
        return -1;
      }
    }
  
    return ret;
  }
  
  // WriteAll writes |in_len| bytes from |in| to |ssl|, resolving any asynchronous
  // operations. It returns the result of the final |SSL_write| call.
  static int WriteAll(SSL *ssl, const uint8_t *in, size_t in_len) {
    const TestConfig *config = GetTestConfig(ssl);
    int ret;
    do {
      ret = SSL_write(ssl, in, in_len);
      if (ret > 0) {
        in += ret;
        in_len -= ret;
      }
    } while ((config->async && RetryAsync(ssl, ret)) || (ret > 0 && in_len > 0));
    return ret;
  }
  
  // DoShutdown calls |SSL_shutdown|, resolving any asynchronous operations. It
  // returns the result of the final |SSL_shutdown| call.
  static int DoShutdown(SSL *ssl) {
    const TestConfig *config = GetTestConfig(ssl);
    int ret;
    do {
      ret = SSL_shutdown(ssl);
    } while (config->async && RetryAsync(ssl, ret));
    return ret;
  }
  
  // DoSendFatalAlert calls |SSL_send_fatal_alert|, resolving any asynchronous
  // operations. It returns the result of the final |SSL_send_fatal_alert| call.
  static int DoSendFatalAlert(SSL *ssl, uint8_t alert) {
    const TestConfig *config = GetTestConfig(ssl);
    int ret;
    do {
      ret = SSL_send_fatal_alert(ssl, alert);
    } while (config->async && RetryAsync(ssl, ret));
    return ret;
  }
  
  static uint16_t GetProtocolVersion(const SSL *ssl) {
    uint16_t version = SSL_version(ssl);
    if (!SSL_is_dtls(ssl)) {
      return version;
    }
    return 0x0201 + ~version;
  }
  
  // CheckHandshakeProperties checks, immediately after |ssl| completes its
  // initial handshake (or False Starts), whether all the properties are
  // consistent with the test configuration and invariants.
  static bool CheckHandshakeProperties(SSL *ssl, bool is_resume) {
    const TestConfig *config = GetTestConfig(ssl);
  
    if (SSL_get_current_cipher(ssl) == nullptr) {
      fprintf(stderr, "null cipher after handshake\n");
      return false;
    }
  
    if (is_resume &&
        (!!SSL_session_reused(ssl) == config->expect_session_miss)) {
      fprintf(stderr, "session was%s reused\n",
              SSL_session_reused(ssl) ? "" : " not");
      return false;
    }
  
    bool expect_handshake_done = is_resume || !config->false_start;
    if (expect_handshake_done != GetTestState(ssl)->handshake_done) {
      fprintf(stderr, "handshake was%s completed\n",
              GetTestState(ssl)->handshake_done ? "" : " not");
      return false;
    }
  
    if (expect_handshake_done && !config->is_server) {
      bool expect_new_session =
          !config->expect_no_session &&
          (!SSL_session_reused(ssl) || config->expect_ticket_renewal) &&
          // Session tickets are sent post-handshake in TLS 1.3.
          GetProtocolVersion(ssl) < TLS1_3_VERSION;
      if (expect_new_session != GetTestState(ssl)->got_new_session) {
        fprintf(stderr,
                "new session was%s cached, but we expected the opposite\n",
                GetTestState(ssl)->got_new_session ? "" : " not");
        return false;
      }
    }
  
    if (config->is_server && !GetTestState(ssl)->early_callback_called) {
      fprintf(stderr, "early callback not called\n");
      return false;
    }
  
    if (!config->expected_server_name.empty()) {
      const char *server_name =
          SSL_get_servername(ssl, TLSEXT_NAMETYPE_host_name);
      if (server_name == nullptr ||
          server_name != config->expected_server_name) {
        fprintf(stderr, "servername mismatch (got %s; want %s)\n",
                server_name, config->expected_server_name.c_str());
        return false;
      }
    }
  
    if (!config->expected_next_proto.empty()) {
      const uint8_t *next_proto;
      unsigned next_proto_len;
      SSL_get0_next_proto_negotiated(ssl, &next_proto, &next_proto_len);
      if (next_proto_len != config->expected_next_proto.size() ||
          OPENSSL_memcmp(next_proto, config->expected_next_proto.data(),
                         next_proto_len) != 0) {
        fprintf(stderr, "negotiated next proto mismatch\n");
        return false;
      }
    }
  
    if (!config->expected_alpn.empty()) {
      const uint8_t *alpn_proto;
      unsigned alpn_proto_len;
      SSL_get0_alpn_selected(ssl, &alpn_proto, &alpn_proto_len);
      if (alpn_proto_len != config->expected_alpn.size() ||
          OPENSSL_memcmp(alpn_proto, config->expected_alpn.data(),
                         alpn_proto_len) != 0) {
        fprintf(stderr, "negotiated alpn proto mismatch\n");
        return false;
      }
    }
  
    if (!config->expected_channel_id.empty()) {
      uint8_t channel_id[64];
      if (!SSL_get_tls_channel_id(ssl, channel_id, sizeof(channel_id))) {
        fprintf(stderr, "no channel id negotiated\n");
        return false;
      }
      if (config->expected_channel_id.size() != 64 ||
          OPENSSL_memcmp(config->expected_channel_id.data(), channel_id, 64) !=
              0) {
        fprintf(stderr, "channel id mismatch\n");
        return false;
      }
    }
  
    if (config->expect_extended_master_secret) {
      if (!SSL_get_extms_support(ssl)) {
        fprintf(stderr, "No EMS for connection when expected");
        return false;
      }
    }
  
    if (!config->expected_ocsp_response.empty()) {
      const uint8_t *data;
      size_t len;
      SSL_get0_ocsp_response(ssl, &data, &len);
      if (config->expected_ocsp_response.size() != len ||
          OPENSSL_memcmp(config->expected_ocsp_response.data(), data, len) != 0) {
        fprintf(stderr, "OCSP response mismatch\n");
        return false;
      }
    }
  
    if (!config->expected_signed_cert_timestamps.empty()) {
      const uint8_t *data;
      size_t len;
      SSL_get0_signed_cert_timestamp_list(ssl, &data, &len);
      if (config->expected_signed_cert_timestamps.size() != len ||
          OPENSSL_memcmp(config->expected_signed_cert_timestamps.data(), data,
                         len) != 0) {
        fprintf(stderr, "SCT list mismatch\n");
        return false;
      }
    }
  
    if (config->expect_verify_result) {
      int expected_verify_result = config->verify_fail ?
        X509_V_ERR_APPLICATION_VERIFICATION :
        X509_V_OK;
  
      if (SSL_get_verify_result(ssl) != expected_verify_result) {
        fprintf(stderr, "Wrong certificate verification result\n");
        return false;
      }
    }
  
    if (config->expect_peer_signature_algorithm != 0 &&
        config->expect_peer_signature_algorithm !=
            SSL_get_peer_signature_algorithm(ssl)) {
      fprintf(stderr, "Peer signature algorithm was %04x, wanted %04x.\n",
              SSL_get_peer_signature_algorithm(ssl),
              config->expect_peer_signature_algorithm);
      return false;
    }
  
    int expect_curve_id = config->expect_curve_id;
    if (is_resume && config->expect_resume_curve_id != 0) {
      expect_curve_id = config->expect_resume_curve_id;
    }
    if (expect_curve_id != 0) {
      uint16_t curve_id = SSL_get_curve_id(ssl);
      if (static_cast<uint16_t>(expect_curve_id) != curve_id) {
        fprintf(stderr, "curve_id was %04x, wanted %04x\n", curve_id,
                static_cast<uint16_t>(expect_curve_id));
        return false;
      }
    }
  
    uint16_t cipher_id =
        static_cast<uint16_t>(SSL_CIPHER_get_id(SSL_get_current_cipher(ssl)));
    if (config->expect_cipher_aes != 0 &&
        EVP_has_aes_hardware() &&
        static_cast<uint16_t>(config->expect_cipher_aes) != cipher_id) {
      fprintf(stderr, "Cipher ID was %04x, wanted %04x (has AES hardware)\n",
              cipher_id, static_cast<uint16_t>(config->expect_cipher_aes));
      return false;
    }
  
    if (config->expect_cipher_no_aes != 0 &&
        !EVP_has_aes_hardware() &&
        static_cast<uint16_t>(config->expect_cipher_no_aes) != cipher_id) {
      fprintf(stderr, "Cipher ID was %04x, wanted %04x (no AES hardware)\n",
              cipher_id, static_cast<uint16_t>(config->expect_cipher_no_aes));
      return false;
    }
  
  
    if (!config->psk.empty()) {
      if (SSL_get_peer_cert_chain(ssl) != nullptr) {
        fprintf(stderr, "Received peer certificate on a PSK cipher.\n");
        return false;
      }
    } else if (!config->is_server || config->require_any_client_certificate) {
      if (SSL_get_peer_cert_chain(ssl) == nullptr) {
        fprintf(stderr, "Received no peer certificate but expected one.\n");
        return false;
      }
    }
  
    if (!config->expect_peer_cert_file.empty()) {
      bssl::UniquePtr<X509> expect_leaf;
      bssl::UniquePtr<STACK_OF(X509)> expect_chain;
      if (!LoadCertificate(&expect_leaf, &expect_chain,
                           config->expect_peer_cert_file)) {
        return false;
      }
  
      // For historical reasons, clients report a chain with a leaf and servers
      // without.
      if (!config->is_server) {
        if (!sk_X509_insert(expect_chain.get(), expect_leaf.get(), 0)) {
          return false;
        }
        X509_up_ref(expect_leaf.get());  // sk_X509_push takes ownership.
      }
  
      bssl::UniquePtr<X509> leaf(SSL_get_peer_certificate(ssl));
      STACK_OF(X509) *chain = SSL_get_peer_cert_chain(ssl);
      if (X509_cmp(leaf.get(), expect_leaf.get()) != 0) {
        fprintf(stderr, "Received a different leaf certificate than expected.\n");
        return false;
      }
  
      if (sk_X509_num(chain) != sk_X509_num(expect_chain.get())) {
        fprintf(stderr, "Received a chain of length %zu instead of %zu.\n",
                sk_X509_num(chain), sk_X509_num(expect_chain.get()));
        return false;
      }
  
      for (size_t i = 0; i < sk_X509_num(chain); i++) {
        if (X509_cmp(sk_X509_value(chain, i),
                     sk_X509_value(expect_chain.get(), i)) != 0) {
          fprintf(stderr, "Chain certificate %zu did not match.\n",
                  i + 1);
          return false;
        }
      }
    }
  
    bool expected_sha256_client_cert = config->expect_sha256_client_cert_initial;
    if (is_resume) {
      expected_sha256_client_cert = config->expect_sha256_client_cert_resume;
    }
  
    if (SSL_get_session(ssl)->peer_sha256_valid != expected_sha256_client_cert) {
      fprintf(stderr,
              "Unexpected SHA-256 client cert state: expected:%d is_resume:%d.\n",
              expected_sha256_client_cert, is_resume);
      return false;
    }
  
    if (expected_sha256_client_cert &&
        SSL_get_session(ssl)->x509_peer != nullptr) {
      fprintf(stderr, "Have both client cert and SHA-256 hash: is_resume:%d.\n",
              is_resume);
      return false;
    }
  
    return true;
  }
  
  // DoExchange runs a test SSL exchange against the peer. On success, it returns
  // true and sets |*out_session| to the negotiated SSL session. If the test is a
  // resumption attempt, |is_resume| is true and |session| is the session from the
  // previous exchange.
  static bool DoExchange(bssl::UniquePtr<SSL_SESSION> *out_session,
                         SSL_CTX *ssl_ctx, const TestConfig *config,
                         bool is_resume, SSL_SESSION *session) {
    bssl::UniquePtr<SSL> ssl(SSL_new(ssl_ctx));
    if (!ssl) {
      return false;
    }
  
    if (!SetTestConfig(ssl.get(), config) ||
        !SetTestState(ssl.get(), std::unique_ptr<TestState>(new TestState))) {
      return false;
    }
  
    if (config->fallback_scsv &&
        !SSL_set_mode(ssl.get(), SSL_MODE_SEND_FALLBACK_SCSV)) {
      return false;
    }
    // Install the certificate synchronously if nothing else will handle it.
    if (!config->use_early_callback &&
        !config->use_old_client_cert_callback &&
        !config->async &&
        !InstallCertificate(ssl.get())) {
      return false;
    }
    if (!config->use_old_client_cert_callback) {
      SSL_set_cert_cb(ssl.get(), CertCallback, nullptr);
    }
    if (config->require_any_client_certificate) {
      SSL_set_verify(ssl.get(), SSL_VERIFY_PEER|SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
                     NULL);
    }
    if (config->verify_peer) {
      SSL_set_verify(ssl.get(), SSL_VERIFY_PEER, NULL);
    }
    if (config->false_start) {
      SSL_set_mode(ssl.get(), SSL_MODE_ENABLE_FALSE_START);
    }
    if (config->cbc_record_splitting) {
      SSL_set_mode(ssl.get(), SSL_MODE_CBC_RECORD_SPLITTING);
    }
    if (config->partial_write) {
      SSL_set_mode(ssl.get(), SSL_MODE_ENABLE_PARTIAL_WRITE);
    }
    if (config->no_tls13) {
      SSL_set_options(ssl.get(), SSL_OP_NO_TLSv1_3);
    }
    if (config->no_tls12) {
      SSL_set_options(ssl.get(), SSL_OP_NO_TLSv1_2);
    }
    if (config->no_tls11) {
      SSL_set_options(ssl.get(), SSL_OP_NO_TLSv1_1);
    }
    if (config->no_tls1) {
      SSL_set_options(ssl.get(), SSL_OP_NO_TLSv1);
    }
    if (config->no_ssl3) {
      SSL_set_options(ssl.get(), SSL_OP_NO_SSLv3);
    }
    if (!config->expected_channel_id.empty() ||
        config->enable_channel_id) {
      SSL_set_tls_channel_id_enabled(ssl.get(), 1);
    }
    if (!config->send_channel_id.empty()) {
      SSL_set_tls_channel_id_enabled(ssl.get(), 1);
      if (!config->async) {
        // The async case will be supplied by |ChannelIdCallback|.
        bssl::UniquePtr<EVP_PKEY> pkey = LoadPrivateKey(config->send_channel_id);
        if (!pkey || !SSL_set1_tls_channel_id(ssl.get(), pkey.get())) {
          return false;
        }
      }
    }
    if (!config->host_name.empty() &&
        !SSL_set_tlsext_host_name(ssl.get(), config->host_name.c_str())) {
      return false;
    }
    if (!config->advertise_alpn.empty() &&
        SSL_set_alpn_protos(ssl.get(),
                            (const uint8_t *)config->advertise_alpn.data(),
                            config->advertise_alpn.size()) != 0) {
      return false;
    }
    if (!config->psk.empty()) {
      SSL_set_psk_client_callback(ssl.get(), PskClientCallback);
      SSL_set_psk_server_callback(ssl.get(), PskServerCallback);
    }
    if (!config->psk_identity.empty() &&
        !SSL_use_psk_identity_hint(ssl.get(), config->psk_identity.c_str())) {
      return false;
    }
    if (!config->srtp_profiles.empty() &&
        !SSL_set_srtp_profiles(ssl.get(), config->srtp_profiles.c_str())) {
      return false;
    }
    if (config->enable_ocsp_stapling &&
        !SSL_enable_ocsp_stapling(ssl.get())) {
      return false;
    }
    if (config->enable_signed_cert_timestamps &&
        !SSL_enable_signed_cert_timestamps(ssl.get())) {
      return false;
    }
    if (config->min_version != 0 &&
        !SSL_set_min_proto_version(ssl.get(), (uint16_t)config->min_version)) {
      return false;
    }
    if (config->max_version != 0 &&
        !SSL_set_max_proto_version(ssl.get(), (uint16_t)config->max_version)) {
      return false;
    }
    if (config->mtu != 0) {
      SSL_set_options(ssl.get(), SSL_OP_NO_QUERY_MTU);
      SSL_set_mtu(ssl.get(), config->mtu);
    }
    if (config->install_ddos_callback) {
      SSL_CTX_set_dos_protection_cb(ssl_ctx, DDoSCallback);
    }
    if (config->renegotiate_once) {
      SSL_set_renegotiate_mode(ssl.get(), ssl_renegotiate_once);
    }
    if (config->renegotiate_freely) {
      SSL_set_renegotiate_mode(ssl.get(), ssl_renegotiate_freely);
    }
    if (config->renegotiate_ignore) {
      SSL_set_renegotiate_mode(ssl.get(), ssl_renegotiate_ignore);
    }
    if (!config->check_close_notify) {
      SSL_set_quiet_shutdown(ssl.get(), 1);
    }
    if (config->p384_only) {
      int nid = NID_secp384r1;
      if (!SSL_set1_curves(ssl.get(), &nid, 1)) {
        return false;
      }
    }
    if (config->enable_all_curves) {
      static const int kAllCurves[] = {
        NID_X9_62_prime256v1, NID_secp384r1, NID_secp521r1, NID_X25519,
      };
      if (!SSL_set1_curves(ssl.get(), kAllCurves,
                           OPENSSL_ARRAY_SIZE(kAllCurves))) {
        return false;
      }
    }
    if (config->initial_timeout_duration_ms > 0) {
      DTLSv1_set_initial_timeout_duration(ssl.get(),
                                          config->initial_timeout_duration_ms);
    }
    if (config->max_cert_list > 0) {
      SSL_set_max_cert_list(ssl.get(), config->max_cert_list);
    }
    if (!is_resume && config->retain_only_sha256_client_cert_initial) {
      SSL_set_retain_only_sha256_of_client_certs(ssl.get(), 1);
    }
    if (is_resume && config->retain_only_sha256_client_cert_resume) {
      SSL_set_retain_only_sha256_of_client_certs(ssl.get(), 1);
    }
  
    int sock = Connect(config->port);
    if (sock == -1) {
      return false;
    }
    SocketCloser closer(sock);
  
    bssl::UniquePtr<BIO> bio(BIO_new_socket(sock, BIO_NOCLOSE));
    if (!bio) {
      return false;
    }
    if (config->is_dtls) {
      bssl::UniquePtr<BIO> packeted = PacketedBioCreate(&g_clock, !config->async);
      if (!packeted) {
        return false;
      }
      GetTestState(ssl.get())->packeted_bio = packeted.get();
      BIO_push(packeted.get(), bio.release());
      bio = std::move(packeted);
    }
    if (config->async) {
      bssl::UniquePtr<BIO> async_scoped =
          config->is_dtls ? AsyncBioCreateDatagram() : AsyncBioCreate();
      if (!async_scoped) {
        return false;
      }
      BIO_push(async_scoped.get(), bio.release());
      GetTestState(ssl.get())->async_bio = async_scoped.get();
      bio = std::move(async_scoped);
    }
    SSL_set_bio(ssl.get(), bio.get(), bio.get());
    bio.release();  // SSL_set_bio takes ownership.
  
    if (session != NULL) {
      if (!config->is_server) {
        if (SSL_set_session(ssl.get(), session) != 1) {
          return false;
        }
      } else if (config->async) {
        // The internal session cache is disabled, so install the session
        // manually.
        SSL_SESSION_up_ref(session);
        GetTestState(ssl.get())->pending_session.reset(session);
      }
    }
  
    if (SSL_get_current_cipher(ssl.get()) != nullptr) {
      fprintf(stderr, "non-null cipher before handshake\n");
      return false;
    }
  
    int ret;
    if (config->implicit_handshake) {
      if (config->is_server) {
        SSL_set_accept_state(ssl.get());
      } else {
        SSL_set_connect_state(ssl.get());
      }
    } else {
      do {
        if (config->is_server) {
          ret = SSL_accept(ssl.get());
        } else {
          ret = SSL_connect(ssl.get());
        }
      } while (config->async && RetryAsync(ssl.get(), ret));
      if (ret != 1 ||
          !CheckHandshakeProperties(ssl.get(), is_resume)) {
        return false;
      }
  
      // Reset the state to assert later that the callback isn't called in
      // renegotations.
      GetTestState(ssl.get())->got_new_session = false;
    }
  
    if (config->export_keying_material > 0) {
      std::vector<uint8_t> result(
          static_cast<size_t>(config->export_keying_material));
      if (!SSL_export_keying_material(
              ssl.get(), result.data(), result.size(),
              config->export_label.data(), config->export_label.size(),
              reinterpret_cast<const uint8_t*>(config->export_context.data()),
              config->export_context.size(), config->use_export_context)) {
        fprintf(stderr, "failed to export keying material\n");
        return false;
      }
      if (WriteAll(ssl.get(), result.data(), result.size()) < 0) {
        return false;
      }
    }
  
    if (config->tls_unique) {
      uint8_t tls_unique[16];
      size_t tls_unique_len;
      if (!SSL_get_tls_unique(ssl.get(), tls_unique, &tls_unique_len,
                              sizeof(tls_unique))) {
        fprintf(stderr, "failed to get tls-unique\n");
        return false;
      }
  
      if (tls_unique_len != 12) {
        fprintf(stderr, "expected 12 bytes of tls-unique but got %u",
                static_cast<unsigned>(tls_unique_len));
        return false;
      }
  
      if (WriteAll(ssl.get(), tls_unique, tls_unique_len) < 0) {
        return false;
      }
    }
  
    if (config->send_alert) {
      if (DoSendFatalAlert(ssl.get(), SSL_AD_DECOMPRESSION_FAILURE) < 0) {
        return false;
      }
      return true;
    }
  
    if (config->write_different_record_sizes) {
      if (config->is_dtls) {
        fprintf(stderr, "write_different_record_sizes not supported for DTLS\n");
        return false;
      }
      // This mode writes a number of different record sizes in an attempt to
      // trip up the CBC record splitting code.
      static const size_t kBufLen = 32769;
      std::unique_ptr<uint8_t[]> buf(new uint8_t[kBufLen]);
      OPENSSL_memset(buf.get(), 0x42, kBufLen);
      static const size_t kRecordSizes[] = {
          0, 1, 255, 256, 257, 16383, 16384, 16385, 32767, 32768, 32769};
      for (size_t i = 0; i < OPENSSL_ARRAY_SIZE(kRecordSizes); i++) {
        const size_t len = kRecordSizes[i];
        if (len > kBufLen) {
          fprintf(stderr, "Bad kRecordSizes value.\n");
          return false;
        }
        if (WriteAll(ssl.get(), buf.get(), len) < 0) {
          return false;
        }
      }
    } else {
      if (config->read_with_unfinished_write) {
        if (!config->async) {
          fprintf(stderr, "-read-with-unfinished-write requires -async.\n");
          return false;
        }
  
        int write_ret = SSL_write(ssl.get(),
                            reinterpret_cast<const uint8_t *>("unfinished"), 10);
        if (SSL_get_error(ssl.get(), write_ret) != SSL_ERROR_WANT_WRITE) {
          fprintf(stderr, "Failed to leave unfinished write.\n");
          return false;
        }
      }
      if (config->shim_writes_first) {
        if (WriteAll(ssl.get(), reinterpret_cast<const uint8_t *>("hello"),
                     5) < 0) {
          return false;
        }
      }
      if (!config->shim_shuts_down) {
        for (;;) {
          static const size_t kBufLen = 16384;
          std::unique_ptr<uint8_t[]> buf(new uint8_t[kBufLen]);
  
          // Read only 512 bytes at a time in TLS to ensure records may be
          // returned in multiple reads.
          int n = DoRead(ssl.get(), buf.get(), config->is_dtls ? kBufLen : 512);
          int err = SSL_get_error(ssl.get(), n);
          if (err == SSL_ERROR_ZERO_RETURN ||
              (n == 0 && err == SSL_ERROR_SYSCALL)) {
            if (n != 0) {
              fprintf(stderr, "Invalid SSL_get_error output\n");
              return false;
            }
            // Stop on either clean or unclean shutdown.
            break;
          } else if (err != SSL_ERROR_NONE) {
            if (n > 0) {
              fprintf(stderr, "Invalid SSL_get_error output\n");
              return false;
            }
            return false;
          }
          // Successfully read data.
          if (n <= 0) {
            fprintf(stderr, "Invalid SSL_get_error output\n");
            return false;
          }
  
          // After a successful read, with or without False Start, the handshake
          // must be complete.
          if (!GetTestState(ssl.get())->handshake_done) {
            fprintf(stderr, "handshake was not completed after SSL_read\n");
            return false;
          }
  
          for (int i = 0; i < n; i++) {
            buf[i] ^= 0xff;
          }
          if (WriteAll(ssl.get(), buf.get(), n) < 0) {
            return false;
          }
        }
      }
    }
  
    if (!config->is_server && !config->false_start &&
        !config->implicit_handshake &&
        // Session tickets are sent post-handshake in TLS 1.3.
        GetProtocolVersion(ssl.get()) < TLS1_3_VERSION &&
        GetTestState(ssl.get())->got_new_session) {
      fprintf(stderr, "new session was established after the handshake\n");
      return false;
    }
  
    if (GetProtocolVersion(ssl.get()) >= TLS1_3_VERSION && !config->is_server) {
      bool expect_new_session =
          !config->expect_no_session && !config->shim_shuts_down;
      if (expect_new_session != GetTestState(ssl.get())->got_new_session) {
        fprintf(stderr,
                "new session was%s cached, but we expected the opposite\n",
                GetTestState(ssl.get())->got_new_session ? "" : " not");
        return false;
      }
    }
  
    if (out_session) {
      *out_session = std::move(GetTestState(ssl.get())->new_session);
    }
  
    ret = DoShutdown(ssl.get());
  
    if (config->shim_shuts_down && config->check_close_notify) {
      // We initiate shutdown, so |SSL_shutdown| will return in two stages. First
      // it returns zero when our close_notify is sent, then one when the peer's
      // is received.
      if (ret != 0) {
        fprintf(stderr, "Unexpected SSL_shutdown result: %d != 0\n", ret);
        return false;
      }
      ret = DoShutdown(ssl.get());
    }
  
    if (ret != 1) {
      fprintf(stderr, "Unexpected SSL_shutdown result: %d != 1\n", ret);
      return false;
    }
  
    if (SSL_total_renegotiations(ssl.get()) !=
        config->expect_total_renegotiations) {
      fprintf(stderr, "Expected %d renegotiations, got %d\n",
              config->expect_total_renegotiations,
              SSL_total_renegotiations(ssl.get()));
      return false;
    }
  
    return true;
  }
  
  class StderrDelimiter {
   public:
    ~StderrDelimiter() { fprintf(stderr, "--- DONE ---\n"); }
  };
  
  int main(int argc, char **argv) {
    // To distinguish ASan's output from ours, add a trailing message to stderr.
    // Anything following this line will be considered an error.
    StderrDelimiter delimiter;
  
  #if defined(OPENSSL_WINDOWS)
    /* Initialize Winsock. */
    WORD wsa_version = MAKEWORD(2, 2);
    WSADATA wsa_data;
    int wsa_err = WSAStartup(wsa_version, &wsa_data);
    if (wsa_err != 0) {
      fprintf(stderr, "WSAStartup failed: %d\n", wsa_err);
      return 1;
    }
    if (wsa_data.wVersion != wsa_version) {
      fprintf(stderr, "Didn't get expected version: %x\n", wsa_data.wVersion);
      return 1;
    }
  #else
    signal(SIGPIPE, SIG_IGN);
  #endif
  
    CRYPTO_library_init();
    g_config_index = SSL_get_ex_new_index(0, NULL, NULL, NULL, NULL);
    g_state_index = SSL_get_ex_new_index(0, NULL, NULL, NULL, TestStateExFree);
    if (g_config_index < 0 || g_state_index < 0) {
      return 1;
    }
  
    TestConfig config;
    if (!ParseConfig(argc - 1, argv + 1, &config)) {
      return Usage(argv[0]);
    }
  
    g_pool = CRYPTO_BUFFER_POOL_new();
  
    // Some code treats the zero time special, so initialize the clock to a
    // non-zero time.
    g_clock.tv_sec = 1234;
    g_clock.tv_usec = 1234;
  
    bssl::UniquePtr<SSL_CTX> ssl_ctx = SetupCtx(&config);
    if (!ssl_ctx) {
      ERR_print_errors_fp(stderr);
      return 1;
    }
  
    bssl::UniquePtr<SSL_SESSION> session;
    for (int i = 0; i < config.resume_count + 1; i++) {
      bool is_resume = i > 0;
      if (is_resume && !config.is_server && !session) {
        fprintf(stderr, "No session to offer.\n");
        return 1;
      }
  
      bssl::UniquePtr<SSL_SESSION> offer_session = std::move(session);
      if (!DoExchange(&session, ssl_ctx.get(), &config, is_resume,
                      offer_session.get())) {
        fprintf(stderr, "Connection %d failed.\n", i + 1);
        ERR_print_errors_fp(stderr);
        return 1;
      }
  
      if (config.resumption_delay != 0) {
        g_clock.tv_sec += config.resumption_delay;
      }
    }
  
    return 0;
  }
  