Integrate BoringSSL shim

The BoringSSL test suite contains numerous tests which OpenSSL does not.

The BoringSSL test runner uses a shim to launch the library and execute the
tests. This is a version of the BoringSSL shim converted to compile against
OpenSSL instead.

This is primarily based on the work of David Benjamin from the BoringSSL
project who did most of the necessary conversion. It also includes a few
other tweaks for opacity changes etc.

This is based on a *very* old version of BoringSSL from commit f277add6c.
That was the last commit known to work with this patched shim. Later
versions may also work but lots of merge conflicts occur when trying to
bring it up to date.

At the moment this has not been integrated into the build system. There is
a very simple standalone makefile in the ossl_shim directory which should
be executed directly before tyring to use the shim.

Reviewed-by: Richard Levitte <levitte@openssl.org>

1 files changed, 1237 insertions, 0 deletions

diff --git a/test/ossl_shim/ossl_shim.cc b/test/ossl_shim/ossl_shim.cc
new file mode 100644
index 0000000000..b1abcf6d6c
--- /dev/null
+++ b/test/ossl_shim/ossl_shim.cc
@@ -0,0 +1,1237 @@
+/* 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/e_os2.h>
+
+#if !defined(OPENSSL_SYS_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>
+#pragma warning(push, 3)
+#include <winsock2.h>
+#include <ws2tcpip.h>
+#pragma warning(pop)
+
+#pragma comment(lib, "Ws2_32.lib")
+#endif
+
+#include <inttypes.h>
+#include <string.h>
+
+#include <openssl/bio.h>
+#include <openssl/buffer.h>
+#include <openssl/crypto.h>
+#include <openssl/dh.h>
+#include <openssl/err.h>
+#include <openssl/evp.h>
+#include <openssl/hmac.h>
+#include <openssl/objects.h>
+#include <openssl/rand.h>
+#include <openssl/ssl.h>
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "crypto/scoped_types.h"
+#include "async_bio.h"
+#include "packeted_bio.h"
+#include "scoped_types.h"
+#include "test_config.h"
+
+
+#if !defined(OPENSSL_SYS_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 {
+  TestState() {
+    // MSVC cannot initialize these inline.
+    memset(&clock, 0, sizeof(clock));
+    memset(&clock_delta, 0, sizeof(clock_delta));
+  }
+
+  // async_bio is async BIO which pauses reads and writes.
+  BIO *async_bio = nullptr;
+  // clock is the current time for the SSL connection.
+  timeval clock;
+  // clock_delta is how far the clock advanced in the most recent failed
+  // |BIO_read|.
+  timeval clock_delta;
+  bool cert_ready = false;
+  ScopedSSL_SESSION session;
+  ScopedSSL_SESSION pending_session;
+  bool early_callback_called = false;
+  bool handshake_done = false;
+  // private_key is the underlying private key used when testing custom keys.
+  ScopedEVP_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;
+};
+
+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 SetConfigPtr(SSL *ssl, const TestConfig *config) {
+  return SSL_set_ex_data(ssl, g_config_index, (void *)config) == 1;
+}
+
+static const TestConfig *GetConfigPtr(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 ScopedX509 LoadCertificate(const std::string &file) {
+  ScopedBIO bio(BIO_new(BIO_s_file()));
+  if (!bio || !BIO_read_filename(bio.get(), file.c_str())) {
+    return nullptr;
+  }
+  return ScopedX509(PEM_read_bio_X509(bio.get(), NULL, NULL, NULL));
+}
+
+static ScopedEVP_PKEY LoadPrivateKey(const std::string &file) {
+  ScopedBIO bio(BIO_new(BIO_s_file()));
+  if (!bio || !BIO_read_filename(bio.get(), file.c_str())) {
+    return nullptr;
+  }
+  return ScopedEVP_PKEY(PEM_read_bio_PrivateKey(bio.get(), NULL, NULL, NULL));
+}
+
+template<typename T>
+struct Free {
+  void operator()(T *buf) {
+    free(buf);
+  }
+};
+
+static bool GetCertificate(SSL *ssl, ScopedX509 *out_x509,
+                           ScopedEVP_PKEY *out_pkey) {
+  const TestConfig *config = GetConfigPtr(ssl);
+
+  if (!config->digest_prefs.empty()) {
+    fprintf(stderr, "Digest prefs not supported.\n");
+    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()) {
+    *out_x509 = LoadCertificate(config->cert_file.c_str());
+    if (!*out_x509) {
+      return false;
+    }
+  }
+  if (!config->ocsp_response.empty()) {
+    fprintf(stderr, "OCSP response not supported.\n");
+    return false;
+  }
+  return true;
+}
+
+static bool InstallCertificate(SSL *ssl) {
+  ScopedX509 x509;
+  ScopedEVP_PKEY pkey;
+  if (!GetCertificate(ssl, &x509, &pkey)) {
+    return false;
+  }
+
+  if (pkey) {
+    TestState *test_state = GetTestState(ssl);
+    const TestConfig *config = GetConfigPtr(ssl);
+    if (!SSL_use_PrivateKey(ssl, pkey.get())) {
+      return false;
+    }
+  }
+
+  if (x509 && !SSL_use_certificate(ssl, x509.get())) {
+    return false;
+  }
+
+  return true;
+}
+
+static int ClientCertCallback(SSL *ssl, X509 **out_x509, EVP_PKEY **out_pkey) {
+  if (GetConfigPtr(ssl)->async && !GetTestState(ssl)->cert_ready) {
+    return -1;
+  }
+
+  ScopedX509 x509;
+  ScopedEVP_PKEY pkey;
+  if (!GetCertificate(ssl, &x509, &pkey)) {
+    return -1;
+  }
+
+  // Return zero for no certificate.
+  if (!x509) {
+    return 0;
+  }
+
+  // Asynchronous private keys are not supported with client_cert_cb.
+  *out_x509 = x509.release();
+  *out_pkey = pkey.release();
+  return 1;
+}
+
+static int VerifySucceed(X509_STORE_CTX *store_ctx, void *arg) {
+  return 1;
+}
+
+static int VerifyFail(X509_STORE_CTX *store_ctx, void *arg) {
+  X509_STORE_CTX_set_error(store_ctx, 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 = GetConfigPtr(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 = GetConfigPtr(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) {
+  const TestConfig *config = GetConfigPtr(ssl);
+  if (config->select_alpn.empty()) {
+    return SSL_TLSEXT_ERR_NOACK;
+  }
+
+  if (!config->expected_advertised_alpn.empty() &&
+      (config->expected_advertised_alpn.size() != inlen ||
+       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 = GetConfigPtr(ssl);
+
+  if (strcmp(hint ? 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);
+  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 = GetConfigPtr(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;
+  }
+
+  memcpy(out_psk, config->psk.data(), config->psk.size());
+  return config->psk.size();
+}
+
+static int CertCallback(SSL *ssl, void *arg) {
+  if (!GetTestState(ssl)->cert_ready) {
+    return -1;
+  }
+  if (!InstallCertificate(ssl)) {
+    return 0;
+  }
+  return 1;
+}
+
+static void InfoCallback(const SSL *ssl, int type, int val) {
+  if (type == SSL_CB_HANDSHAKE_DONE) {
+    if (GetConfigPtr(ssl)->handshake_never_done) {
+      fprintf(stderr, "handshake completed\n");
+      // Abort before any expected error code is printed, to ensure the overall
+      // test fails.
+      abort();
+    }
+    GetTestState(ssl)->handshake_done = true;
+  }
+}
+
+static int NewSessionCallback(SSL *ssl, SSL_SESSION *session) {
+  GetTestState(ssl)->got_new_session = true;
+  // BoringSSL passes a reference to |session|.
+  SSL_SESSION_free(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) {
+  // This is just test code, so use the all-zeros key.
+  static const uint8_t kZeros[16] = {0};
+
+  if (encrypt) {
+    memcpy(key_name, kZeros, sizeof(kZeros));
+    RAND_bytes(iv, 16);
+  } else if (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 GetConfigPtr(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 (GetConfigPtr(ssl)->custom_extension_skip) {
+    return 0;
+  }
+  if (GetConfigPtr(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 ||
+      memcmp(contents, kCustomExtensionContents, contents_len) != 0) {
+    *out_alert_value = SSL_AD_DECODE_ERROR;
+    return 0;
+  }
+
+  return 1;
+}
+
+// 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;
+  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 ScopedSSL_CTX SetupCtx(const TestConfig *config) {
+  ScopedSSL_CTX ssl_ctx(SSL_CTX_new(
+      config->is_dtls ? DTLS_method() : TLS_method()));
+  if (!ssl_ctx) {
+    return nullptr;
+  }
+
+  SSL_CTX_set_security_level(ssl_ctx.get(), 0);
+
+  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;
+  }
+
+  if (!config->cipher_tls10.empty() || !config->cipher_tls11.empty()) {
+    fprintf(stderr, "version-specific cipher lists not supported.\n");
+    return nullptr;
+  }
+
+  DH *tmpdh;
+
+  if (config->use_sparse_dh_prime) {
+    BIGNUM *p, *g;
+    p = BN_new();
+    g = BN_new();
+    tmpdh = DH_new();
+    if (p == NULL || g == NULL || tmpdh == NULL) {
+        BN_free(p);
+        BN_free(g);
+        DH_free(tmpdh);
+        return nullptr;
+    }
+    // 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(
+            &p,
+            "1000000000000000000000000000000000000000000000000000000000000000"
+            "0000000000000000000000000000000000000000000000000000000000000000"
+            "0000000000000000000000000000000000000000000000000000000000000000"
+            "0000000000000000000000000000000000000000000000000000000000000028"
+            "3") == 0 ||
+        !BN_set_word(g, 2)) {
+      BN_free(p);
+      BN_free(g);
+      DH_free(tmpdh);
+      return nullptr;
+    }
+    DH_set0_pqg(tmpdh, p, NULL, g);
+  } else {
+      tmpdh = DH_get_2048_256();
+  }
+
+  ScopedDH dh(tmpdh);
+
+  if (!dh || !SSL_CTX_set_tmp_dh(ssl_ctx.get(), dh.get())) {
+    return nullptr;
+  }
+
+  SSL_CTX_set_session_cache_mode(ssl_ctx.get(), SSL_SESS_CACHE_BOTH);
+
+  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()) {
+    SSL_CTX_set_alpn_select_cb(ssl_ctx.get(), AlpnSelectCallback, NULL);
+  }
+
+  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()) {
+    fprintf(stderr, "SCTs not supported.\n");
+    return nullptr;
+  }
+
+  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;
+  }
+
+  const TestConfig *config = GetConfigPtr(ssl);
+  TestState *test_state = GetTestState(ssl);
+  if (test_state->clock_delta.tv_usec != 0 ||
+      test_state->clock_delta.tv_sec != 0) {
+    // Process the timeout and retry.
+    test_state->clock.tv_usec += test_state->clock_delta.tv_usec;
+    test_state->clock.tv_sec += test_state->clock.tv_usec / 1000000;
+    test_state->clock.tv_usec %= 1000000;
+    test_state->clock.tv_sec += test_state->clock_delta.tv_sec;
+    memset(&test_state->clock_delta, 0, sizeof(test_state->clock_delta));
+
+    // The DTLS retransmit logic silently ignores write failures. So the test
+    // may progress, allow writes through synchronously.
+    if (config->async) {
+      AsyncBioEnforceWriteQuota(test_state->async_bio, false);
+    }
+    int timeout_ret = DTLSv1_handle_timeout(ssl);
+    if (config->async) {
+      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_X509_LOOKUP:
+      test_state->cert_ready = true;
+      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 = GetConfigPtr(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 = SSL_read(ssl, out, max_out);
+    if (config->async) {
+      AsyncBioEnforceWriteQuota(test_state->async_bio, true);
+    }
+  } while (config->async && RetryAsync(ssl, ret));
+  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 = GetConfigPtr(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 = GetConfigPtr(ssl);
+  int ret;
+  do {
+    ret = SSL_shutdown(ssl);
+  } while (config->async && RetryAsync(ssl, ret));
+  return ret;
+}
+
+// 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 = GetConfigPtr(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);
+    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->expected_server_name.empty()) {
+    const char *server_name =
+        SSL_get_servername(ssl, TLSEXT_NAMETYPE_host_name);
+    if (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_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() ||
+        memcmp(certificate_types,
+               config->expected_certificate_types.data(),
+               certificate_types_len) != 0) {
+      fprintf(stderr, "certificate types mismatch\n");
+      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() ||
+        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() ||
+        memcmp(alpn_proto, config->expected_alpn.data(),
+               alpn_proto_len) != 0) {
+      fprintf(stderr, "negotiated alpn proto 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->is_server) {
+    /* Clients should expect a peer certificate chain iff this was not a PSK
+     * cipher suite. */
+    if (config->psk.empty()) {
+      if (SSL_get_peer_cert_chain(ssl) == nullptr) {
+        fprintf(stderr, "Missing peer certificate chain!\n");
+        return false;
+      }
+    } else if (SSL_get_peer_cert_chain(ssl) != nullptr) {
+      fprintf(stderr, "Unexpected peer certificate chain!\n");
+      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(ScopedSSL_SESSION *out_session, SSL_CTX *ssl_ctx,
+                       const TestConfig *config, bool is_resume,
+                       SSL_SESSION *session) {
+  ScopedSSL ssl(SSL_new(ssl_ctx));
+  if (!ssl) {
+    return false;
+  }
+
+  if (!SetConfigPtr(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;
+  }
+  if (!config->use_early_callback && !config->use_old_client_cert_callback) {
+    if (config->async) {
+      SSL_set_cert_cb(ssl.get(), CertCallback, NULL);
+    } else if (!InstallCertificate(ssl.get())) {
+      return false;
+    }
+  } else {
+    fprintf(stderr, "Early callback not supported.\n");
+    return false;
+  }
+  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) {
+    fprintf(stderr, "False Start not supported\n");
+    return false;
+  }
+  if (config->partial_write) {
+    SSL_set_mode(ssl.get(), SSL_MODE_ENABLE_PARTIAL_WRITE);
+  }
+  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()) {
+    fprintf(stderr, "Channel ID not supported\n");
+    return false;
+  }
+  if (!config->send_channel_id.empty()) {
+    fprintf(stderr, "Channel ID not supported\n");
+    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_tlsext_use_srtp(ssl.get(), config->srtp_profiles.c_str())) {
+    return false;
+  }
+  if (config->enable_ocsp_stapling) {
+    fprintf(stderr, "OCSP stapling not supported (with the same API).\n");
+    return false;
+  }
+  if (config->enable_signed_cert_timestamps) {
+    fprintf(stderr, "SCTs not supported (with the same API).\n");
+    return false;
+  }
+  if (config->min_version != 0) {
+    SSL_set_min_proto_version(ssl.get(), (uint16_t)config->min_version);
+  }
+  if (config->max_version != 0) {
+    SSL_set_max_proto_version(ssl.get(), (uint16_t)config->max_version);
+  }
+  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) {
+    fprintf(stderr, "DDoS callback not supported.\n");
+    return false;
+  }
+  if (config->renegotiate_once) {
+    fprintf(stderr, "renegotiate_once not supported.\n");
+    return false;
+  }
+  if (config->renegotiate_freely) {
+    // This is always on for OpenSSL.
+  }
+  if (config->renegotiate_ignore) {
+    fprintf(stderr, "renegotiate_ignore not supported.\n");
+    return false;
+  }
+  if (!config->check_close_notify) {
+    SSL_set_quiet_shutdown(ssl.get(), 1);
+  }
+  if (config->disable_npn) {
+    fprintf(stderr, "SSL_OP_DISABLE_NPN not supported.\n");
+    return false;
+  }
+  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,
+                         sizeof(kAllCurves) / sizeof(kAllCurves[0]))) {
+      return false;
+    }
+  }
+
+  int sock = Connect(config->port);
+  if (sock == -1) {
+    return false;
+  }
+  SocketCloser closer(sock);
+
+  ScopedBIO bio(BIO_new_socket(sock, BIO_NOCLOSE));
+  if (!bio) {
+    return false;
+  }
+  if (config->is_dtls) {
+    ScopedBIO packeted =
+        PacketedBioCreate(&GetTestState(ssl.get())->clock_delta);
+    BIO_push(packeted.get(), bio.release());
+    bio = std::move(packeted);
+  }
+  if (config->async) {
+    ScopedBIO async_scoped =
+        config->is_dtls ? AsyncBioCreateDatagram() : AsyncBioCreate();
+    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;
+      }
+    }
+  }
+
+#if 0
+  // KNOWN BUG: OpenSSL's SSL_get_current_cipher behaves incorrectly when
+  // offering resumption.
+  if (SSL_get_current_cipher(ssl.get()) != nullptr) {
+    fprintf(stderr, "non-null cipher before handshake\n");
+    return false;
+  }
+#endif
+
+  int ret;
+  if (config->implicit_handshake) {
+    if (config->is_server) {
+      SSL_set_accept_state(ssl.get());
+    } else {