/* 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. */

#include <stdio.h>
#include <string.h>
#include <time.h>

#include <algorithm>
#include <limits>
#include <string>
#include <utility>
#include <vector>

#include <gtest/gtest.h>

#include <openssl/aead.h>
#include <openssl/base64.h>
#include <openssl/bio.h>
#include <openssl/cipher.h>
#include <openssl/crypto.h>
#include <openssl/err.h>
#include <openssl/hmac.h>
#include <openssl/pem.h>
#include <openssl/sha.h>
#include <openssl/ssl.h>
#include <openssl/rand.h>
#include <openssl/x509.h>

#include "internal.h"
#include "../crypto/internal.h"
#include "../crypto/test/test_util.h"

#if defined(OPENSSL_WINDOWS)
// Windows defines struct timeval in winsock2.h.
OPENSSL_MSVC_PRAGMA(warning(push, 3))
#include <winsock2.h>
OPENSSL_MSVC_PRAGMA(warning(pop))
#else
#include <sys/time.h>
#endif

#if defined(OPENSSL_THREADS)
#include <thread>
#endif


BSSL_NAMESPACE_BEGIN

namespace {

#define TRACED_CALL(code)                     \
  do {                                        \
    SCOPED_TRACE("<- called from here");      \
    code;                                     \
    if (::testing::Test::HasFatalFailure()) { \
      return;                                 \
    }                                         \
  } while (false)

struct VersionParam {
  uint16_t version;
  enum { is_tls, is_dtls } ssl_method;
  const char name[8];
};

static const size_t kTicketKeyLen = 48;

static const VersionParam kAllVersions[] = {
    {TLS1_VERSION, VersionParam::is_tls, "TLS1"},
    {TLS1_1_VERSION, VersionParam::is_tls, "TLS1_1"},
    {TLS1_2_VERSION, VersionParam::is_tls, "TLS1_2"},
    {TLS1_3_VERSION, VersionParam::is_tls, "TLS1_3"},
    {DTLS1_VERSION, VersionParam::is_dtls, "DTLS1"},
    {DTLS1_2_VERSION, VersionParam::is_dtls, "DTLS1_2"},
};

struct ExpectedCipher {
  unsigned long id;
  int in_group_flag;
};

struct CipherTest {
  // The rule string to apply.
  const char *rule;
  // The list of expected ciphers, in order.
  std::vector<ExpectedCipher> expected;
  // True if this cipher list should fail in strict mode.
  bool strict_fail;
};

struct CurveTest {
  // The rule string to apply.
  const char *rule;
  // The list of expected curves, in order.
  std::vector<uint16_t> expected;
};

template <typename T>
class UnownedSSLExData {
 public:
  UnownedSSLExData() {
    index_ = SSL_get_ex_new_index(0, nullptr, nullptr, nullptr, nullptr);
  }

  T *Get(const SSL *ssl) {
    return index_ < 0 ? nullptr
                      : static_cast<T *>(SSL_get_ex_data(ssl, index_));
  }

  bool Set(SSL *ssl, T *t) {
    return index_ >= 0 && SSL_set_ex_data(ssl, index_, t);
  }

 private:
  int index_;
};

static const CipherTest kCipherTests[] = {
    // Selecting individual ciphers should work.
    {
        "ECDHE-ECDSA-CHACHA20-POLY1305:"
        "ECDHE-RSA-CHACHA20-POLY1305:"
        "ECDHE-ECDSA-AES128-GCM-SHA256:"
        "ECDHE-RSA-AES128-GCM-SHA256",
        {
            {TLS1_CK_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, 0},
            {TLS1_CK_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256, 0},
            {TLS1_CK_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, 0},
            {TLS1_CK_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 0},
        },
        false,
    },
    // + reorders selected ciphers to the end, keeping their relative order.
    {
        "ECDHE-ECDSA-CHACHA20-POLY1305:"
        "ECDHE-RSA-CHACHA20-POLY1305:"
        "ECDHE-ECDSA-AES128-GCM-SHA256:"
        "ECDHE-RSA-AES128-GCM-SHA256:"
        "+aRSA",
        {
            {TLS1_CK_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, 0},
            {TLS1_CK_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, 0},
            {TLS1_CK_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256, 0},
            {TLS1_CK_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 0},
        },
        false,
    },
    // ! banishes ciphers from future selections.
    {
        "!aRSA:"
        "ECDHE-ECDSA-CHACHA20-POLY1305:"
        "ECDHE-RSA-CHACHA20-POLY1305:"
        "ECDHE-ECDSA-AES128-GCM-SHA256:"
        "ECDHE-RSA-AES128-GCM-SHA256",
        {
            {TLS1_CK_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, 0},
            {TLS1_CK_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, 0},
        },
        false,
    },
    // Multiple masks can be ANDed in a single rule.
    {
        "kRSA+AESGCM+AES128",
        {
            {TLS1_CK_RSA_WITH_AES_128_GCM_SHA256, 0},
        },
        false,
    },
    // - removes selected ciphers, but preserves their order for future
    // selections. Select AES_128_GCM, but order the key exchanges RSA,
    // ECDHE_RSA.
    {
        "ALL:-kECDHE:"
        "-kRSA:-ALL:"
        "AESGCM+AES128+aRSA",
        {
            {TLS1_CK_RSA_WITH_AES_128_GCM_SHA256, 0},
            {TLS1_CK_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 0},
        },
        false,
    },
    // Unknown selectors are no-ops, except in strict mode.
    {
        "ECDHE-ECDSA-CHACHA20-POLY1305:"
        "ECDHE-RSA-CHACHA20-POLY1305:"
        "ECDHE-ECDSA-AES128-GCM-SHA256:"
        "ECDHE-RSA-AES128-GCM-SHA256:"
        "BOGUS1",
        {
            {TLS1_CK_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, 0},
            {TLS1_CK_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256, 0},
            {TLS1_CK_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, 0},
            {TLS1_CK_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 0},
        },
        true,
    },
    // Unknown selectors are no-ops, except in strict mode.
    {
        "ECDHE-ECDSA-CHACHA20-POLY1305:"
        "ECDHE-RSA-CHACHA20-POLY1305:"
        "ECDHE-ECDSA-AES128-GCM-SHA256:"
        "ECDHE-RSA-AES128-GCM-SHA256:"
        "-BOGUS2:+BOGUS3:!BOGUS4",
        {
            {TLS1_CK_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, 0},
            {TLS1_CK_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256, 0},
            {TLS1_CK_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, 0},
            {TLS1_CK_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 0},
        },
        true,
    },
    // Square brackets specify equi-preference groups.
    {
        "[ECDHE-ECDSA-CHACHA20-POLY1305|ECDHE-ECDSA-AES128-GCM-SHA256]:"
        "[ECDHE-RSA-CHACHA20-POLY1305]:"
        "ECDHE-RSA-AES128-GCM-SHA256",
        {
            {TLS1_CK_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, 1},
            {TLS1_CK_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, 0},
            {TLS1_CK_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256, 0},
            {TLS1_CK_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 0},
        },
        false,
    },
    // Standard names may be used instead of OpenSSL names.
    {
        "[TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256|"
        "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256]:"
        "[TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256]:"
        "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256",
        {
            {TLS1_CK_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, 1},
            {TLS1_CK_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, 0},
            {TLS1_CK_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256, 0},
            {TLS1_CK_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 0},
        },
        false,
    },
    // @STRENGTH performs a stable strength-sort of the selected ciphers and
    // only the selected ciphers.
    {
        // To simplify things, banish all but {ECDHE_RSA,RSA} x
        // {CHACHA20,AES_256_CBC,AES_128_CBC} x SHA1.
        "!AESGCM:!3DES:"
        // Order some ciphers backwards by strength.
        "ALL:-CHACHA20:-AES256:-AES128:-ALL:"
        // Select ECDHE ones and sort them by strength. Ties should resolve
        // based on the order above.
        "kECDHE:@STRENGTH:-ALL:"
        // Now bring back everything uses RSA. ECDHE_RSA should be first, sorted
        // by strength. Then RSA, backwards by strength.
        "aRSA",
        {
            {TLS1_CK_ECDHE_RSA_WITH_AES_256_CBC_SHA, 0},
            {TLS1_CK_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256, 0},
            {TLS1_CK_ECDHE_RSA_WITH_AES_128_CBC_SHA, 0},
            {TLS1_CK_RSA_WITH_AES_128_SHA, 0},
            {TLS1_CK_RSA_WITH_AES_256_SHA, 0},
        },
        false,
    },
    // Additional masks after @STRENGTH get silently discarded.
    //
    // TODO(davidben): Make this an error. If not silently discarded, they get
    // interpreted as + opcodes which are very different.
    {
        "ECDHE-RSA-AES128-GCM-SHA256:"
        "ECDHE-RSA-AES256-GCM-SHA384:"
        "@STRENGTH+AES256",
        {
            {TLS1_CK_ECDHE_RSA_WITH_AES_256_GCM_SHA384, 0},
            {TLS1_CK_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 0},
        },
        false,
    },
    {
        "ECDHE-RSA-AES128-GCM-SHA256:"
        "ECDHE-RSA-AES256-GCM-SHA384:"
        "@STRENGTH+AES256:"
        "ECDHE-RSA-CHACHA20-POLY1305",
        {
            {TLS1_CK_ECDHE_RSA_WITH_AES_256_GCM_SHA384, 0},
            {TLS1_CK_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 0},
            {TLS1_CK_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256, 0},
        },
        false,
    },
    // Exact ciphers may not be used in multi-part rules; they are treated
    // as unknown aliases.
    {
        "ECDHE-ECDSA-AES128-GCM-SHA256:"
        "ECDHE-RSA-AES128-GCM-SHA256:"
        "!ECDHE-RSA-AES128-GCM-SHA256+RSA:"
        "!ECDSA+ECDHE-ECDSA-AES128-GCM-SHA256",
        {
            {TLS1_CK_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, 0},
            {TLS1_CK_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 0},
        },
        true,
    },
    // SSLv3 matches everything that existed before TLS 1.2.
    {
        "AES128-SHA:ECDHE-RSA-AES128-GCM-SHA256:!SSLv3",
        {
            {TLS1_CK_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 0},
        },
        false,
    },
    // TLSv1.2 matches everything added in TLS 1.2.
    {
        "AES128-SHA:ECDHE-RSA-AES128-GCM-SHA256:!TLSv1.2",
        {
            {TLS1_CK_RSA_WITH_AES_128_SHA, 0},
        },
        false,
    },
    // The two directives have no intersection.  But each component is valid, so
    // even in strict mode it is accepted.
    {
        "AES128-SHA:ECDHE-RSA-AES128-GCM-SHA256:!TLSv1.2+SSLv3",
        {
            {TLS1_CK_RSA_WITH_AES_128_SHA, 0},
            {TLS1_CK_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 0},
        },
        false,
    },
    // Spaces, semi-colons and commas are separators.
    {
        "AES128-SHA: ECDHE-RSA-AES128-GCM-SHA256 AES256-SHA ,ECDHE-ECDSA-AES128-GCM-SHA256 ; AES128-GCM-SHA256",
        {
            {TLS1_CK_RSA_WITH_AES_128_SHA, 0},
            {TLS1_CK_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 0},
            {TLS1_CK_RSA_WITH_AES_256_SHA, 0},
            {TLS1_CK_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, 0},
            {TLS1_CK_RSA_WITH_AES_128_GCM_SHA256, 0},
        },
        // …but not in strict mode.
        true,
    },
};

static const char *kBadRules[] = {
  // Invalid brackets.
  "[ECDHE-RSA-CHACHA20-POLY1305|ECDHE-RSA-AES128-GCM-SHA256",
  "RSA]",
  "[[RSA]]",
  // Operators inside brackets.
  "[+RSA]",
  // Unknown directive.
  "@BOGUS",
  // Empty cipher lists error at SSL_CTX_set_cipher_list.
  "",
  "BOGUS",
  // COMPLEMENTOFDEFAULT is empty.
  "COMPLEMENTOFDEFAULT",
  // Invalid command.
  "?BAR",
  // Special operators are not allowed if groups are used.
  "[ECDHE-RSA-CHACHA20-POLY1305|ECDHE-RSA-AES128-GCM-SHA256]:+FOO",
  "[ECDHE-RSA-CHACHA20-POLY1305|ECDHE-RSA-AES128-GCM-SHA256]:!FOO",
  "[ECDHE-RSA-CHACHA20-POLY1305|ECDHE-RSA-AES128-GCM-SHA256]:-FOO",
  "[ECDHE-RSA-CHACHA20-POLY1305|ECDHE-RSA-AES128-GCM-SHA256]:@STRENGTH",
  // Opcode supplied, but missing selector.
  "+",
  // Spaces are forbidden in equal-preference groups.
  "[AES128-SHA | AES128-SHA256]",
};

static const char *kMustNotIncludeNull[] = {
  "ALL",
  "DEFAULT",
  "HIGH",
  "FIPS",
  "SHA",
  "SHA1",
  "RSA",
  "SSLv3",
  "TLSv1",
  "TLSv1.2",
};

static const CurveTest kCurveTests[] = {
  {
    "P-256",
    { SSL_CURVE_SECP256R1 },
  },
  {
    "P-256:CECPQ2",
    { SSL_CURVE_SECP256R1, SSL_CURVE_CECPQ2 },
  },

  {
    "P-256:P-384:P-521:X25519",
    {
      SSL_CURVE_SECP256R1,
      SSL_CURVE_SECP384R1,
      SSL_CURVE_SECP521R1,
      SSL_CURVE_X25519,
    },
  },
  {
    "prime256v1:secp384r1:secp521r1:x25519",
    {
      SSL_CURVE_SECP256R1,
      SSL_CURVE_SECP384R1,
      SSL_CURVE_SECP521R1,
      SSL_CURVE_X25519,
    },
  },
};

static const char *kBadCurvesLists[] = {
  "",
  ":",
  "::",
  "P-256::X25519",
  "RSA:P-256",
  "P-256:RSA",
  "X25519:P-256:",
  ":X25519:P-256",
};

static std::string CipherListToString(SSL_CTX *ctx) {
  bool in_group = false;
  std::string ret;
  const STACK_OF(SSL_CIPHER) *ciphers = SSL_CTX_get_ciphers(ctx);
  for (size_t i = 0; i < sk_SSL_CIPHER_num(ciphers); i++) {
    const SSL_CIPHER *cipher = sk_SSL_CIPHER_value(ciphers, i);
    if (!in_group && SSL_CTX_cipher_in_group(ctx, i)) {
      ret += "\t[\n";
      in_group = true;
    }
    ret += "\t";
    if (in_group) {
      ret += "  ";
    }
    ret += SSL_CIPHER_get_name(cipher);
    ret += "\n";
    if (in_group && !SSL_CTX_cipher_in_group(ctx, i)) {
      ret += "\t]\n";
      in_group = false;
    }
  }
  return ret;
}

static bool CipherListsEqual(SSL_CTX *ctx,
                             const std::vector<ExpectedCipher> &expected) {
  const STACK_OF(SSL_CIPHER) *ciphers = SSL_CTX_get_ciphers(ctx);
  if (sk_SSL_CIPHER_num(ciphers) != expected.size()) {
    return false;
  }

  for (size_t i = 0; i < expected.size(); i++) {
    const SSL_CIPHER *cipher = sk_SSL_CIPHER_value(ciphers, i);
    if (expected[i].id != SSL_CIPHER_get_id(cipher) ||
        expected[i].in_group_flag != !!SSL_CTX_cipher_in_group(ctx, i)) {
      return false;
    }
  }

  return true;
}

TEST(GrowableArrayTest, Resize) {
  GrowableArray<size_t> array;
  ASSERT_TRUE(array.empty());
  EXPECT_EQ(array.size(), 0u);

  ASSERT_TRUE(array.Push(42));
  ASSERT_TRUE(!array.empty());
  EXPECT_EQ(array.size(), 1u);

  // Force a resize operation to occur
  for (size_t i = 0; i < 16; i++) {
    ASSERT_TRUE(array.Push(i + 1));
  }

  EXPECT_EQ(array.size(), 17u);

  // Verify that expected values are still contained in array
  for (size_t i = 0; i < array.size(); i++) {
    EXPECT_EQ(array[i], i == 0 ? 42 : i);
  }
}

TEST(GrowableArrayTest, MoveConstructor) {
  GrowableArray<size_t> array;
  for (size_t i = 0; i < 100; i++) {
    ASSERT_TRUE(array.Push(i));
  }

  GrowableArray<size_t> array_moved(std::move(array));
  for (size_t i = 0; i < 100; i++) {
    EXPECT_EQ(array_moved[i], i);
  }
}

TEST(GrowableArrayTest, GrowableArrayContainingGrowableArrays) {
  // Representative example of a struct that contains a GrowableArray.
  struct TagAndArray {
    size_t tag;
    GrowableArray<size_t> array;
  };

  GrowableArray<TagAndArray> array;
  for (size_t i = 0; i < 100; i++) {
    TagAndArray elem;
    elem.tag = i;
    for (size_t j = 0; j < i; j++) {
      ASSERT_TRUE(elem.array.Push(j));
    }
    ASSERT_TRUE(array.Push(std::move(elem)));
  }
  EXPECT_EQ(array.size(), static_cast<size_t>(100));

  GrowableArray<TagAndArray> array_moved(std::move(array));
  EXPECT_EQ(array_moved.size(), static_cast<size_t>(100));
  size_t count = 0;
  for (const TagAndArray &elem : array_moved) {
    // Test the square bracket operator returns the same value as iteration.
    EXPECT_EQ(&elem, &array_moved[count]);

    EXPECT_EQ(elem.tag, count);
    EXPECT_EQ(elem.array.size(), count);
    for (size_t j = 0; j < count; j++) {
      EXPECT_EQ(elem.array[j], j);
    }
    count++;
  }
}

TEST(SSLTest, CipherRules) {
  for (const CipherTest &t : kCipherTests) {
    SCOPED_TRACE(t.rule);
    bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));
    ASSERT_TRUE(ctx);

    // Test lax mode.
    ASSERT_TRUE(SSL_CTX_set_cipher_list(ctx.get(), t.rule));
    EXPECT_TRUE(CipherListsEqual(ctx.get(), t.expected))
        << "Cipher rule evaluated to:\n"
        << CipherListToString(ctx.get());

    // Test strict mode.
    if (t.strict_fail) {
      EXPECT_FALSE(SSL_CTX_set_strict_cipher_list(ctx.get(), t.rule));
    } else {
      ASSERT_TRUE(SSL_CTX_set_strict_cipher_list(ctx.get(), t.rule));
      EXPECT_TRUE(CipherListsEqual(ctx.get(), t.expected))
          << "Cipher rule evaluated to:\n"
          << CipherListToString(ctx.get());
    }
  }

  for (const char *rule : kBadRules) {
    SCOPED_TRACE(rule);
    bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));
    ASSERT_TRUE(ctx);

    EXPECT_FALSE(SSL_CTX_set_cipher_list(ctx.get(), rule));
    ERR_clear_error();
  }

  for (const char *rule : kMustNotIncludeNull) {
    SCOPED_TRACE(rule);
    bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));
    ASSERT_TRUE(ctx);

    ASSERT_TRUE(SSL_CTX_set_strict_cipher_list(ctx.get(), rule));
    for (const SSL_CIPHER *cipher : SSL_CTX_get_ciphers(ctx.get())) {
      EXPECT_NE(NID_undef, SSL_CIPHER_get_cipher_nid(cipher));
    }
  }
}

TEST(SSLTest, CurveRules) {
  for (const CurveTest &t : kCurveTests) {
    SCOPED_TRACE(t.rule);
    bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));
    ASSERT_TRUE(ctx);

    ASSERT_TRUE(SSL_CTX_set1_curves_list(ctx.get(), t.rule));
    ASSERT_EQ(t.expected.size(), ctx->supported_group_list.size());
    for (size_t i = 0; i < t.expected.size(); i++) {
      EXPECT_EQ(t.expected[i], ctx->supported_group_list[i]);
    }
  }

  for (const char *rule : kBadCurvesLists) {
    SCOPED_TRACE(rule);
    bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));
    ASSERT_TRUE(ctx);

    EXPECT_FALSE(SSL_CTX_set1_curves_list(ctx.get(), rule));
    ERR_clear_error();
  }
}

// kOpenSSLSession is a serialized SSL_SESSION.
static const char kOpenSSLSession[] =
    "MIIFqgIBAQICAwMEAsAvBCAG5Q1ndq4Yfmbeo1zwLkNRKmCXGdNgWvGT3cskV0yQ"
    "kAQwJlrlzkAWBOWiLj/jJ76D7l+UXoizP2KI2C7I2FccqMmIfFmmkUy32nIJ0mZH"
    "IWoJoQYCBFRDO46iBAICASyjggR6MIIEdjCCA16gAwIBAgIIK9dUvsPWSlUwDQYJ"
    "KoZIhvcNAQEFBQAwSTELMAkGA1UEBhMCVVMxEzARBgNVBAoTCkdvb2dsZSBJbmMx"
    "JTAjBgNVBAMTHEdvb2dsZSBJbnRlcm5ldCBBdXRob3JpdHkgRzIwHhcNMTQxMDA4"
    "MTIwNzU3WhcNMTUwMTA2MDAwMDAwWjBoMQswCQYDVQQGEwJVUzETMBEGA1UECAwK"
    "Q2FsaWZvcm5pYTEWMBQGA1UEBwwNTW91bnRhaW4gVmlldzETMBEGA1UECgwKR29v"
    "Z2xlIEluYzEXMBUGA1UEAwwOd3d3Lmdvb2dsZS5jb20wggEiMA0GCSqGSIb3DQEB"
    "AQUAA4IBDwAwggEKAoIBAQCcKeLrplAC+Lofy8t/wDwtB6eu72CVp0cJ4V3lknN6"
    "huH9ct6FFk70oRIh/VBNBBz900jYy+7111Jm1b8iqOTQ9aT5C7SEhNcQFJvqzH3e"
    "MPkb6ZSWGm1yGF7MCQTGQXF20Sk/O16FSjAynU/b3oJmOctcycWYkY0ytS/k3LBu"
    "Id45PJaoMqjB0WypqvNeJHC3q5JjCB4RP7Nfx5jjHSrCMhw8lUMW4EaDxjaR9KDh"
    "PLgjsk+LDIySRSRDaCQGhEOWLJZVLzLo4N6/UlctCHEllpBUSvEOyFga52qroGjg"
    "rf3WOQ925MFwzd6AK+Ich0gDRg8sQfdLH5OuP1cfLfU1AgMBAAGjggFBMIIBPTAd"
    "BgNVHSUEFjAUBggrBgEFBQcDAQYIKwYBBQUHAwIwGQYDVR0RBBIwEIIOd3d3Lmdv"
    "b2dsZS5jb20waAYIKwYBBQUHAQEEXDBaMCsGCCsGAQUFBzAChh9odHRwOi8vcGtp"
    "Lmdvb2dsZS5jb20vR0lBRzIuY3J0MCsGCCsGAQUFBzABhh9odHRwOi8vY2xpZW50"
    "czEuZ29vZ2xlLmNvbS9vY3NwMB0GA1UdDgQWBBQ7a+CcxsZByOpc+xpYFcIbnUMZ"
    "hTAMBgNVHRMBAf8EAjAAMB8GA1UdIwQYMBaAFErdBhYbvPZotXb1gba7Yhq6WoEv"
    "MBcGA1UdIAQQMA4wDAYKKwYBBAHWeQIFATAwBgNVHR8EKTAnMCWgI6Ahhh9odHRw"
    "Oi8vcGtpLmdvb2dsZS5jb20vR0lBRzIuY3JsMA0GCSqGSIb3DQEBBQUAA4IBAQCa"
    "OXCBdoqUy5bxyq+Wrh1zsyyCFim1PH5VU2+yvDSWrgDY8ibRGJmfff3r4Lud5kal"
    "dKs9k8YlKD3ITG7P0YT/Rk8hLgfEuLcq5cc0xqmE42xJ+Eo2uzq9rYorc5emMCxf"
    "5L0TJOXZqHQpOEcuptZQ4OjdYMfSxk5UzueUhA3ogZKRcRkdB3WeWRp+nYRhx4St"
    "o2rt2A0MKmY9165GHUqMK9YaaXHDXqBu7Sefr1uSoAP9gyIJKeihMivsGqJ1TD6Z"
    "cc6LMe+dN2P8cZEQHtD1y296ul4Mivqk3jatUVL8/hCwgch9A8O4PGZq9WqBfEWm"
    "IyHh1dPtbg1lOXdYCWtjpAIEAKUDAgEUqQUCAwGJwKqBpwSBpBwUQvoeOk0Kg36S"
    "YTcLEkXqKwOBfF9vE4KX0NxeLwjcDTpsuh3qXEaZ992r1N38VDcyS6P7I6HBYN9B"
    "sNHM362zZnY27GpTw+Kwd751CLoXFPoaMOe57dbBpXoro6Pd3BTbf/Tzr88K06yE"
    "OTDKPNj3+inbMaVigtK4PLyPq+Topyzvx9USFgRvyuoxn0Hgb+R0A3j6SLRuyOdA"
    "i4gv7Y5oliyntgMBAQA=";

// kCustomSession is a custom serialized SSL_SESSION generated by
// filling in missing fields from |kOpenSSLSession|. This includes
// providing |peer_sha256|, so |peer| is not serialized.
static const char kCustomSession[] =
    "MIIBZAIBAQICAwMEAsAvBCAG5Q1ndq4Yfmbeo1zwLkNRKmCXGdNgWvGT3cskV0yQ"
    "kAQwJlrlzkAWBOWiLj/jJ76D7l+UXoizP2KI2C7I2FccqMmIfFmmkUy32nIJ0mZH"
    "IWoJoQYCBFRDO46iBAICASykAwQBAqUDAgEUqAcEBXdvcmxkqQUCAwGJwKqBpwSB"
    "pBwUQvoeOk0Kg36SYTcLEkXqKwOBfF9vE4KX0NxeLwjcDTpsuh3qXEaZ992r1N38"
    "VDcyS6P7I6HBYN9BsNHM362zZnY27GpTw+Kwd751CLoXFPoaMOe57dbBpXoro6Pd"
    "3BTbf/Tzr88K06yEOTDKPNj3+inbMaVigtK4PLyPq+Topyzvx9USFgRvyuoxn0Hg"
    "b+R0A3j6SLRuyOdAi4gv7Y5oliynrSIEIAYGBgYGBgYGBgYGBgYGBgYGBgYGBgYG"
    "BgYGBgYGBgYGrgMEAQevAwQBBLADBAEF";

// kBoringSSLSession is a serialized SSL_SESSION generated from bssl client.
static const char kBoringSSLSession[] =
    "MIIRwQIBAQICAwMEAsAvBCDdoGxGK26mR+8lM0uq6+k9xYuxPnwAjpcF9n0Yli9R"
    "kQQwbyshfWhdi5XQ1++7n2L1qqrcVlmHBPpr6yknT/u4pUrpQB5FZ7vqvNn8MdHf"
    "9rWgoQYCBFXgs7uiBAICHCCjggR6MIIEdjCCA16gAwIBAgIIf+yfD7Y6UicwDQYJ"
    "KoZIhvcNAQELBQAwSTELMAkGA1UEBhMCVVMxEzARBgNVBAoTCkdvb2dsZSBJbmMx"
    "JTAjBgNVBAMTHEdvb2dsZSBJbnRlcm5ldCBBdXRob3JpdHkgRzIwHhcNMTUwODEy"
    "MTQ1MzE1WhcNMTUxMTEwMDAwMDAwWjBoMQswCQYDVQQGEwJVUzETMBEGA1UECAwK"
    "Q2FsaWZvcm5pYTEWMBQGA1UEBwwNTW91bnRhaW4gVmlldzETMBEGA1UECgwKR29v"
    "Z2xlIEluYzEXMBUGA1UEAwwOd3d3Lmdvb2dsZS5jb20wggEiMA0GCSqGSIb3DQEB"
    "AQUAA4IBDwAwggEKAoIBAQC0MeG5YGQ0t+IeJeoneP/PrhEaieibeKYkbKVLNZpo"
    "PLuBinvhkXZo3DC133NpCBpy6ZktBwamqyixAyuk/NU6OjgXqwwxfQ7di1AInLIU"
    "792c7hFyNXSUCG7At8Ifi3YwBX9Ba6u/1d6rWTGZJrdCq3QU11RkKYyTq2KT5mce"
    "Tv9iGKqSkSTlp8puy/9SZ/3DbU3U+BuqCFqeSlz7zjwFmk35acdCilpJlVDDN5C/"
    "RCh8/UKc8PaL+cxlt531qoTENvYrflBno14YEZlCBZsPiFeUSILpKEj3Ccwhy0eL"
    "EucWQ72YZU8mUzXBoXGn0zA0crFl5ci/2sTBBGZsylNBAgMBAAGjggFBMIIBPTAd"
    "BgNVHSUEFjAUBggrBgEFBQcDAQYIKwYBBQUHAwIwGQYDVR0RBBIwEIIOd3d3Lmdv"
    "b2dsZS5jb20waAYIKwYBBQUHAQEEXDBaMCsGCCsGAQUFBzAChh9odHRwOi8vcGtp"
    "Lmdvb2dsZS5jb20vR0lBRzIuY3J0MCsGCCsGAQUFBzABhh9odHRwOi8vY2xpZW50"
    "czEuZ29vZ2xlLmNvbS9vY3NwMB0GA1UdDgQWBBS/bzHxcE73Q4j3slC4BLbMtLjG"
    "GjAMBgNVHRMBAf8EAjAAMB8GA1UdIwQYMBaAFErdBhYbvPZotXb1gba7Yhq6WoEv"
    "MBcGA1UdIAQQMA4wDAYKKwYBBAHWeQIFATAwBgNVHR8EKTAnMCWgI6Ahhh9odHRw"
    "Oi8vcGtpLmdvb2dsZS5jb20vR0lBRzIuY3JsMA0GCSqGSIb3DQEBCwUAA4IBAQAb"
    "qdWPZEHk0X7iKPCTHL6S3w6q1eR67goxZGFSM1lk1hjwyu7XcLJuvALVV9uY3ovE"
    "kQZSHwT+pyOPWQhsSjO+1GyjvCvK/CAwiUmBX+bQRGaqHsRcio7xSbdVcajQ3bXd"
    "X+s0WdbOpn6MStKAiBVloPlSxEI8pxY6x/BBCnTIk/+DMB17uZlOjG3vbAnkDkP+"
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    "f07vR03r349Iz/KTzk95rlFtX0IU+KYNxFNsanIXZ+C9FYGRXkwhHcvFb4qMUB1y"
    "TTlM80jBMOwyjZXmjRAhpAIEAKUDAgEUqQUCAwGJwKqBpwSBpOgebbmn9NRUtMWH"
    "+eJpqA5JLMFSMCChOsvKey3toBaCNGU7HfAEiiXNuuAdCBoK262BjQc2YYfqFzqH"
    "zuppopXCvhohx7j/tnCNZIMgLYt/O9SXK2RYI5z8FhCCHvB4CbD5G0LGl5EFP27s"
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    "0Yj+8fAiBtbQriIEIN2L8ZlpaVrdN5KFNdvcmOxJu81P8q53X55xQyGTnGWwsgMC"
    "ARezggvvMIIEdjCCA16gAwIBAgIIf+yfD7Y6UicwDQYJKoZIhvcNAQELBQAwSTEL"
    "MAkGA1UEBhMCVVMxEzARBgNVBAoTCkdvb2dsZSBJbmMxJTAjBgNVBAMTHEdvb2ds"
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    "A1UEBwwNTW91bnRhaW4gVmlldzETMBEGA1UECgwKR29vZ2xlIEluYzEXMBUGA1UE"
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    "AQC0MeG5YGQ0t+IeJeoneP/PrhEaieibeKYkbKVLNZpoPLuBinvhkXZo3DC133Np"
    "CBpy6ZktBwamqyixAyuk/NU6OjgXqwwxfQ7di1AInLIU792c7hFyNXSUCG7At8If"
    "i3YwBX9Ba6u/1d6rWTGZJrdCq3QU11RkKYyTq2KT5mceTv9iGKqSkSTlp8puy/9S"
    "Z/3DbU3U+BuqCFqeSlz7zjwFmk35acdCilpJlVDDN5C/RCh8/UKc8PaL+cxlt531"
    "qoTENvYrflBno14YEZlCBZsPiFeUSILpKEj3Ccwhy0eLEucWQ72YZU8mUzXBoXGn"
    "0zA0crFl5ci/2sTBBGZsylNBAgMBAAGjggFBMIIBPTAdBgNVHSUEFjAUBggrBgEF"
    "BQcDAQYIKwYBBQUHAwIwGQYDVR0RBBIwEIIOd3d3Lmdvb2dsZS5jb20waAYIKwYB"
    "BQUHAQEEXDBaMCsGCCsGAQUFBzAChh9odHRwOi8vcGtpLmdvb2dsZS5jb20vR0lB"
    "RzIuY3J0MCsGCCsGAQUFBzABhh9odHRwOi8vY2xpZW50czEuZ29vZ2xlLmNvbS9v"
    "Y3NwMB0GA1UdDgQWBBS/bzHxcE73Q4j3slC4BLbMtLjGGjAMBgNVHRMBAf8EAjAA"
    "MB8GA1UdIwQYMBaAFErdBhYbvPZotXb1gba7Yhq6WoEvMBcGA1UdIAQQMA4wDAYK"
    "KwYBBAHWeQIFATAwBgNVHR8EKTAnMCWgI6Ahhh9odHRwOi8vcGtpLmdvb2dsZS5j"
    "b20vR0lBRzIuY3JsMA0GCSqGSIb3DQEBCwUAA4IBAQAbqdWPZEHk0X7iKPCTHL6S"
    "3w6q1eR67goxZGFSM1lk1hjwyu7XcLJuvALVV9uY3ovEkQZSHwT+pyOPWQhsSjO+"
    "1GyjvCvK/CAwiUmBX+bQRGaqHsRcio7xSbdVcajQ3bXdX+s0WdbOpn6MStKAiBVl"
    "oPlSxEI8pxY6x/BBCnTIk/+DMB17uZlOjG3vbAnkDkP+n0OTucD9sHV7EVj9XUxi"
    "51nOfNBCN/s7lpUjDS/NJ4k3iwOtbCPswiot8vLO779af07vR03r349Iz/KTzk95"
    "rlFtX0IU+KYNxFNsanIXZ+C9FYGRXkwhHcvFb4qMUB1yTTlM80jBMOwyjZXmjRAh"
    "MIID8DCCAtigAwIBAgIDAjqDMA0GCSqGSIb3DQEBCwUAMEIxCzAJBgNVBAYTAlVT"
    "MRYwFAYDVQQKEw1HZW9UcnVzdCBJbmMuMRswGQYDVQQDExJHZW9UcnVzdCBHbG9i"
    "YWwgQ0EwHhcNMTMwNDA1MTUxNTU2WhcNMTYxMjMxMjM1OTU5WjBJMQswCQYDVQQG"
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    "bmV0IEF1dGhvcml0eSBHMjCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEB"
    "AJwqBHdc2FCROgajguDYUEi8iT/xGXAaiEZ+4I/F8YnOIe5a/mENtzJEiaB0C1NP"
    "VaTOgmKV7utZX8bhBYASxF6UP7xbSDj0U/ck5vuR6RXEz/RTDfRK/J9U3n2+oGtv"
    "h8DQUB8oMANA2ghzUWx//zo8pzcGjr1LEQTrfSTe5vn8MXH7lNVg8y5Kr0LSy+rE"
    "ahqyzFPdFUuLH8gZYR/Nnag+YyuENWllhMgZxUYi+FOVvuOAShDGKuy6lyARxzmZ"
    "EASg8GF6lSWMTlJ14rbtCMoU/M4iarNOz0YDl5cDfsCx3nuvRTPPuj5xt970JSXC"
    "DTWJnZ37DhF5iR43xa+OcmkCAwEAAaOB5zCB5DAfBgNVHSMEGDAWgBTAephojYn7"
    "qwVkDBF9qn1luMrMTjAdBgNVHQ4EFgQUSt0GFhu89mi1dvWBtrtiGrpagS8wDgYD"
    "VR0PAQH/BAQDAgEGMC4GCCsGAQUFBwEBBCIwIDAeBggrBgEFBQcwAYYSaHR0cDov"
    "L2cuc3ltY2QuY29tMBIGA1UdEwEB/wQIMAYBAf8CAQAwNQYDVR0fBC4wLDAqoCig"
    "JoYkaHR0cDovL2cuc3ltY2IuY29tL2NybHMvZ3RnbG9iYWwuY3JsMBcGA1UdIAQQ"
    "MA4wDAYKKwYBBAHWeQIFATANBgkqhkiG9w0BAQsFAAOCAQEAqvqpIM1qZ4PtXtR+"
    "3h3Ef+AlBgDFJPupyC1tft6dgmUsgWM0Zj7pUsIItMsv91+ZOmqcUHqFBYx90SpI"
    "hNMJbHzCzTWf84LuUt5oX+QAihcglvcpjZpNy6jehsgNb1aHA30DP9z6eX0hGfnI"
    "Oi9RdozHQZJxjyXON/hKTAAj78Q1EK7gI4BzfE00LshukNYQHpmEcxpw8u1VDu4X"
    "Bupn7jLrLN1nBz/2i8Jw3lsA5rsb0zYaImxssDVCbJAJPZPpZAkiDoUGn8JzIdPm"
    "X4DkjYUiOnMDsWCOrmji9D6X52ASCWg23jrW4kOVWzeBkoEfu43XrVJkFleW2V40"
    "fsg12DCCA30wggLmoAMCAQICAxK75jANBgkqhkiG9w0BAQUFADBOMQswCQYDVQQG"
    "EwJVUzEQMA4GA1UEChMHRXF1aWZheDEtMCsGA1UECxMkRXF1aWZheCBTZWN1cmUg"
    "Q2VydGlmaWNhdGUgQXV0aG9yaXR5MB4XDTAyMDUyMTA0MDAwMFoXDTE4MDgyMTA0"
    "MDAwMFowQjELMAkGA1UEBhMCVVMxFjAUBgNVBAoTDUdlb1RydXN0IEluYy4xGzAZ"
    "BgNVBAMTEkdlb1RydXN0IEdsb2JhbCBDQTCCASIwDQYJKoZIhvcNAQEBBQADggEP"
    "ADCCAQoCggEBANrMGGMw/fQXIxpWflvfPGw45HG3eJHUvKHYTPioQ7YD6U0hBwiI"
    "2lgvZjkpvQV4i5046AW3an5xpObEYKaw74DkiSgPniXW7YPzraaRx5jJQhg1FJ2t"
    "mEaSLk/K8YdDwRaVVy1Q74ktgHpXrfLuX2vSAI25FPgUFTXZwEaje3LIkb/JVSvN"
    "0Jc+nCZkzN/Ogxlxyk7m1NV7qRnNVd7I7NJeOFPlXE+MLf5QIzb8ZubLjqQ5GQC3"
    "lQI5kQsO/jgu0R0FmvZNPm8PBx2vLB6PYDni+jZTEznUXiYr2z2oFL0y6xgDKFIE"
    "ceWrMz3hOLsHNoRinHnqFjD0X8Ar6HFr5PkCAwEAAaOB8DCB7TAfBgNVHSMEGDAW"
    "gBRI5mj5K9KylddH2CMgEE8zmJCf1DAdBgNVHQ4EFgQUwHqYaI2J+6sFZAwRfap9"
    "ZbjKzE4wDwYDVR0TAQH/BAUwAwEB/zAOBgNVHQ8BAf8EBAMCAQYwOgYDVR0fBDMw"
    "MTAvoC2gK4YpaHR0cDovL2NybC5nZW90cnVzdC5jb20vY3Jscy9zZWN1cmVjYS5j"
    "cmwwTgYDVR0gBEcwRTBDBgRVHSAAMDswOQYIKwYBBQUHAgEWLWh0dHBzOi8vd3d3"
    "Lmdlb3RydXN0LmNvbS9yZXNvdXJjZXMvcmVwb3NpdG9yeTANBgkqhkiG9w0BAQUF"
    "AAOBgQB24RJuTksWEoYwBrKBCM/wCMfHcX5m7sLt1Dsf//DwyE7WQziwuTB9GNBV"
    "g6JqyzYRnOhIZqNtf7gT1Ef+i1pcc/yu2RsyGTirlzQUqpbS66McFAhJtrvlke+D"
    "NusdVm/K2rxzY5Dkf3s+Iss9B+1fOHSc4wNQTqGvmO5h8oQ/Eg==";

// kBadSessionExtraField is a custom serialized SSL_SESSION generated by replacing
// the final (optional) element of |kCustomSession| with tag number 30.
static const char kBadSessionExtraField[] =
    "MIIBdgIBAQICAwMEAsAvBCAG5Q1ndq4Yfmbeo1zwLkNRKmCXGdNgWvGT3cskV0yQ"
    "kAQwJlrlzkAWBOWiLj/jJ76D7l+UXoizP2KI2C7I2FccqMmIfFmmkUy32nIJ0mZH"
    "IWoJoQYCBFRDO46iBAICASykAwQBAqUDAgEUphAEDnd3dy5nb29nbGUuY29tqAcE"
    "BXdvcmxkqQUCAwGJwKqBpwSBpBwUQvoeOk0Kg36SYTcLEkXqKwOBfF9vE4KX0Nxe"
    "LwjcDTpsuh3qXEaZ992r1N38VDcyS6P7I6HBYN9BsNHM362zZnY27GpTw+Kwd751"
    "CLoXFPoaMOe57dbBpXoro6Pd3BTbf/Tzr88K06yEOTDKPNj3+inbMaVigtK4PLyP"
    "q+Topyzvx9USFgRvyuoxn0Hgb+R0A3j6SLRuyOdAi4gv7Y5oliynrSIEIAYGBgYG"
    "BgYGBgYGBgYGBgYGBgYGBgYGBgYGBgYGBgYGrgMEAQevAwQBBL4DBAEF";

// kBadSessionVersion is a custom serialized SSL_SESSION generated by replacing
// the version of |kCustomSession| with 2.
static const char kBadSessionVersion[] =
    "MIIBdgIBAgICAwMEAsAvBCAG5Q1ndq4Yfmbeo1zwLkNRKmCXGdNgWvGT3cskV0yQ"
    "kAQwJlrlzkAWBOWiLj/jJ76D7l+UXoizP2KI2C7I2FccqMmIfFmmkUy32nIJ0mZH"
    "IWoJoQYCBFRDO46iBAICASykAwQBAqUDAgEUphAEDnd3dy5nb29nbGUuY29tqAcE"
    "BXdvcmxkqQUCAwGJwKqBpwSBpBwUQvoeOk0Kg36SYTcLEkXqKwOBfF9vE4KX0Nxe"
    "LwjcDTpsuh3qXEaZ992r1N38VDcyS6P7I6HBYN9BsNHM362zZnY27GpTw+Kwd751"
    "CLoXFPoaMOe57dbBpXoro6Pd3BTbf/Tzr88K06yEOTDKPNj3+inbMaVigtK4PLyP"
    "q+Topyzvx9USFgRvyuoxn0Hgb+R0A3j6SLRuyOdAi4gv7Y5oliynrSIEIAYGBgYG"
    "BgYGBgYGBgYGBgYGBgYGBgYGBgYGBgYGBgYGrgMEAQevAwQBBLADBAEF";

// kBadSessionTrailingData is a custom serialized SSL_SESSION with trailing data
// appended.
static const char kBadSessionTrailingData[] =
    "MIIBdgIBAQICAwMEAsAvBCAG5Q1ndq4Yfmbeo1zwLkNRKmCXGdNgWvGT3cskV0yQ"
    "kAQwJlrlzkAWBOWiLj/jJ76D7l+UXoizP2KI2C7I2FccqMmIfFmmkUy32nIJ0mZH"
    "IWoJoQYCBFRDO46iBAICASykAwQBAqUDAgEUphAEDnd3dy5nb29nbGUuY29tqAcE"
    "BXdvcmxkqQUCAwGJwKqBpwSBpBwUQvoeOk0Kg36SYTcLEkXqKwOBfF9vE4KX0Nxe"
    "LwjcDTpsuh3qXEaZ992r1N38VDcyS6P7I6HBYN9BsNHM362zZnY27GpTw+Kwd751"
    "CLoXFPoaMOe57dbBpXoro6Pd3BTbf/Tzr88K06yEOTDKPNj3+inbMaVigtK4PLyP"
    "q+Topyzvx9USFgRvyuoxn0Hgb+R0A3j6SLRuyOdAi4gv7Y5oliynrSIEIAYGBgYG"
    "BgYGBgYGBgYGBgYGBgYGBgYGBgYGBgYGBgYGrgMEAQevAwQBBLADBAEFAAAA";

static bool DecodeBase64(std::vector<uint8_t> *out, const char *in) {
  size_t len;
  if (!EVP_DecodedLength(&len, strlen(in))) {
    fprintf(stderr, "EVP_DecodedLength failed\n");
    return false;
  }

  out->resize(len);
  if (!EVP_DecodeBase64(out->data(), &len, len, (const uint8_t *)in,
                        strlen(in))) {
    fprintf(stderr, "EVP_DecodeBase64 failed\n");
    return false;
  }
  out->resize(len);
  return true;
}

TEST(SSLTest, SessionEncoding) {
  for (const char *input_b64 : {
           kOpenSSLSession,
           kCustomSession,
           kBoringSSLSession,
       }) {
    SCOPED_TRACE(std::string(input_b64));
    // Decode the input.
    std::vector<uint8_t> input;
    ASSERT_TRUE(DecodeBase64(&input, input_b64));

    // Verify the SSL_SESSION decodes.
    bssl::UniquePtr<SSL_CTX> ssl_ctx(SSL_CTX_new(TLS_method()));
    ASSERT_TRUE(ssl_ctx);
    bssl::UniquePtr<SSL_SESSION> session(
        SSL_SESSION_from_bytes(input.data(), input.size(), ssl_ctx.get()));
    ASSERT_TRUE(session) << "SSL_SESSION_from_bytes failed";

    // Verify the SSL_SESSION encoding round-trips.
    size_t encoded_len;
    bssl::UniquePtr<uint8_t> encoded;
    uint8_t *encoded_raw;
    ASSERT_TRUE(SSL_SESSION_to_bytes(session.get(), &encoded_raw, &encoded_len))
        << "SSL_SESSION_to_bytes failed";
    encoded.reset(encoded_raw);
    EXPECT_EQ(Bytes(encoded.get(), encoded_len), Bytes(input))
        << "SSL_SESSION_to_bytes did not round-trip";

    // Verify the SSL_SESSION also decodes with the legacy API.
    const uint8_t *cptr = input.data();
    session.reset(d2i_SSL_SESSION(NULL, &cptr, input.size()));
    ASSERT_TRUE(session) << "d2i_SSL_SESSION failed";
    EXPECT_EQ(cptr, input.data() + input.size());

    // Verify the SSL_SESSION encoding round-trips via the legacy API.
    int len = i2d_SSL_SESSION(session.get(), NULL);
    ASSERT_GT(len, 0) << "i2d_SSL_SESSION failed";
    ASSERT_EQ(static_cast<size_t>(len), input.size())
        << "i2d_SSL_SESSION(NULL) returned invalid length";

    encoded.reset((uint8_t *)OPENSSL_malloc(input.size()));
    ASSERT_TRUE(encoded);

    uint8_t *ptr = encoded.get();
    len = i2d_SSL_SESSION(session.get(), &ptr);
    ASSERT_GT(len, 0) << "i2d_SSL_SESSION failed";
    ASSERT_EQ(static_cast<size_t>(len), input.size())
        << "i2d_SSL_SESSION(NULL) returned invalid length";
    ASSERT_EQ(ptr, encoded.get() + input.size())
        << "i2d_SSL_SESSION did not advance ptr correctly";
    EXPECT_EQ(Bytes(encoded.get(), encoded_len), Bytes(input))
        << "SSL_SESSION_to_bytes did not round-trip";
  }

  for (const char *input_b64 : {
           kBadSessionExtraField,
           kBadSessionVersion,
           kBadSessionTrailingData,
       }) {
    SCOPED_TRACE(std::string(input_b64));
    std::vector<uint8_t> input;
    ASSERT_TRUE(DecodeBase64(&input, input_b64));

    // Verify that the SSL_SESSION fails to decode.
    bssl::UniquePtr<SSL_CTX> ssl_ctx(SSL_CTX_new(TLS_method()));
    ASSERT_TRUE(ssl_ctx);
    bssl::UniquePtr<SSL_SESSION> session(
        SSL_SESSION_from_bytes(input.data(), input.size(), ssl_ctx.get()));
    EXPECT_FALSE(session) << "SSL_SESSION_from_bytes unexpectedly succeeded";
    ERR_clear_error();
  }
}

static void ExpectDefaultVersion(uint16_t min_version, uint16_t max_version,
                                 const SSL_METHOD *(*method)(void)) {
  bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(method()));
  ASSERT_TRUE(ctx);
  EXPECT_EQ(min_version, SSL_CTX_get_min_proto_version(ctx.get()));
  EXPECT_EQ(max_version, SSL_CTX_get_max_proto_version(ctx.get()));
}

TEST(SSLTest, DefaultVersion) {
  ExpectDefaultVersion(TLS1_VERSION, TLS1_3_VERSION, &TLS_method);
  ExpectDefaultVersion(TLS1_VERSION, TLS1_VERSION, &TLSv1_method);
  ExpectDefaultVersion(TLS1_1_VERSION, TLS1_1_VERSION, &TLSv1_1_method);
  ExpectDefaultVersion(TLS1_2_VERSION, TLS1_2_VERSION, &TLSv1_2_method);
  ExpectDefaultVersion(DTLS1_VERSION, DTLS1_2_VERSION, &DTLS_method);
  ExpectDefaultVersion(DTLS1_VERSION, DTLS1_VERSION, &DTLSv1_method);
  ExpectDefaultVersion(DTLS1_2_VERSION, DTLS1_2_VERSION, &DTLSv1_2_method);
}

TEST(SSLTest, CipherProperties) {
  static const struct {
    int id;
    const char *standard_name;
    int cipher_nid;
    int digest_nid;
    int kx_nid;
    int auth_nid;
    int prf_nid;
  } kTests[] = {
      {
          SSL3_CK_RSA_DES_192_CBC3_SHA,
          "TLS_RSA_WITH_3DES_EDE_CBC_SHA",
          NID_des_ede3_cbc,
          NID_sha1,
          NID_kx_rsa,
          NID_auth_rsa,
          NID_md5_sha1,
      },
      {
          TLS1_CK_RSA_WITH_AES_128_SHA,
          "TLS_RSA_WITH_AES_128_CBC_SHA",
          NID_aes_128_cbc,
          NID_sha1,
          NID_kx_rsa,
          NID_auth_rsa,
          NID_md5_sha1,
      },
      {
          TLS1_CK_PSK_WITH_AES_256_CBC_SHA,
          "TLS_PSK_WITH_AES_256_CBC_SHA",
          NID_aes_256_cbc,
          NID_sha1,
          NID_kx_psk,
          NID_auth_psk,
          NID_md5_sha1,
      },
      {
          TLS1_CK_ECDHE_RSA_WITH_AES_128_CBC_SHA,
          "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA",
          NID_aes_128_cbc,
          NID_sha1,
          NID_kx_ecdhe,
          NID_auth_rsa,
          NID_md5_sha1,
      },
      {
          TLS1_CK_ECDHE_RSA_WITH_AES_256_CBC_SHA,
          "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA",
          NID_aes_256_cbc,
          NID_sha1,
          NID_kx_ecdhe,
          NID_auth_rsa,
          NID_md5_sha1,
      },
      {
          TLS1_CK_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
          "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256",
          NID_aes_128_gcm,
          NID_undef,
          NID_kx_ecdhe,
          NID_auth_rsa,
          NID_sha256,
      },
      {
          TLS1_CK_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
          "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256",
          NID_aes_128_gcm,
          NID_undef,
          NID_kx_ecdhe,
          NID_auth_ecdsa,
          NID_sha256,
      },
      {
          TLS1_CK_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
          "TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384",
          NID_aes_256_gcm,
          NID_undef,
          NID_kx_ecdhe,
          NID_auth_ecdsa,
          NID_sha384,
      },
      {
          TLS1_CK_ECDHE_PSK_WITH_AES_128_CBC_SHA,
          "TLS_ECDHE_PSK_WITH_AES_128_CBC_SHA",
          NID_aes_128_cbc,
          NID_sha1,
          NID_kx_ecdhe,
          NID_auth_psk,
          NID_md5_sha1,
      },
      {
          TLS1_CK_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
          "TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256",
          NID_chacha20_poly1305,
          NID_undef,
          NID_kx_ecdhe,
          NID_auth_rsa,
          NID_sha256,
      },
      {
          TLS1_CK_AES_256_GCM_SHA384,
          "TLS_AES_256_GCM_SHA384",
          NID_aes_256_gcm,
          NID_undef,
          NID_kx_any,
          NID_auth_any,
          NID_sha384,
      },
      {
          TLS1_CK_AES_128_GCM_SHA256,
          "TLS_AES_128_GCM_SHA256",
          NID_aes_128_gcm,
          NID_undef,
          NID_kx_any,
          NID_auth_any,
          NID_sha256,
      },
      {
          TLS1_CK_CHACHA20_POLY1305_SHA256,
          "TLS_CHACHA20_POLY1305_SHA256",
          NID_chacha20_poly1305,
          NID_undef,
          NID_kx_any,
          NID_auth_any,
          NID_sha256,
      },
  };

  for (const auto &t : kTests) {
    SCOPED_TRACE(t.standard_name);

    const SSL_CIPHER *cipher = SSL_get_cipher_by_value(t.id & 0xffff);
    ASSERT_TRUE(cipher);
    EXPECT_STREQ(t.standard_name, SSL_CIPHER_standard_name(cipher));

    bssl::UniquePtr<char> rfc_name(SSL_CIPHER_get_rfc_name(cipher));
    ASSERT_TRUE(rfc_name);
    EXPECT_STREQ(t.standard_name, rfc_name.get());

    EXPECT_EQ(t.cipher_nid, SSL_CIPHER_get_cipher_nid(cipher));
    EXPECT_EQ(t.digest_nid, SSL_CIPHER_get_digest_nid(cipher));
    EXPECT_EQ(t.kx_nid, SSL_CIPHER_get_kx_nid(cipher));
    EXPECT_EQ(t.auth_nid, SSL_CIPHER_get_auth_nid(cipher));
    EXPECT_EQ(t.prf_nid, SSL_CIPHER_get_prf_nid(cipher));
  }
}

// CreateSessionWithTicket returns a sample |SSL_SESSION| with the specified
// version and ticket length or nullptr on failure.
static bssl::UniquePtr<SSL_SESSION> CreateSessionWithTicket(uint16_t version,
                                                            size_t ticket_len) {
  std::vector<uint8_t> der;
  if (!DecodeBase64(&der, kOpenSSLSession)) {
    return nullptr;
  }

  bssl::UniquePtr<SSL_CTX> ssl_ctx(SSL_CTX_new(TLS_method()));
  if (!ssl_ctx) {
    return nullptr;
  }
  // Use a garbage ticket.
  std::vector<uint8_t> ticket(ticket_len, 'a');
  bssl::UniquePtr<SSL_SESSION> session(
      SSL_SESSION_from_bytes(der.data(), der.size(), ssl_ctx.get()));
  if (!session ||
      !SSL_SESSION_set_protocol_version(session.get(), version) ||
      !SSL_SESSION_set_ticket(session.get(), ticket.data(), ticket.size())) {
    return nullptr;
  }
  // Fix up the timeout.
#if defined(BORINGSSL_UNSAFE_DETERMINISTIC_MODE)
  SSL_SESSION_set_time(session.get(), 1234);
#else
  SSL_SESSION_set_time(session.get(), time(nullptr));
#endif
  return session;
}

static bool GetClientHello(SSL *ssl, std::vector<uint8_t> *out) {
  bssl::UniquePtr<BIO> bio(BIO_new(BIO_s_mem()));
  if (!bio) {
    return false;
  }
  // Do not configure a reading BIO, but record what's written to a memory BIO.
  BIO_up_ref(bio.get());
  SSL_set_bio(ssl, nullptr /* rbio */, bio.get());
  int ret = SSL_connect(ssl);
  if (ret > 0) {
    // SSL_connect should fail without a BIO to write to.
    return false;
  }
  ERR_clear_error();

  const uint8_t *client_hello;
  size_t client_hello_len;
  if (!BIO_mem_contents(bio.get(), &client_hello, &client_hello_len)) {
    return false;
  }
  *out = std::vector<uint8_t>(client_hello, client_hello + client_hello_len);
  return true;
}

// GetClientHelloLen creates a client SSL connection with the specified version
// and ticket length. It returns the length of the ClientHello, not including
// the record header, on success and zero on error.
static size_t GetClientHelloLen(uint16_t max_version, uint16_t session_version,
                                size_t ticket_len) {
  bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));
  bssl::UniquePtr<SSL_SESSION> session =
      CreateSessionWithTicket(session_version, ticket_len);
  if (!ctx || !session) {
    return 0;
  }

  // Set a one-element cipher list so the baseline ClientHello is unpadded.
  bssl::UniquePtr<SSL> ssl(SSL_new(ctx.get()));
  if (!ssl || !SSL_set_session(ssl.get(), session.get()) ||
      !SSL_set_strict_cipher_list(ssl.get(), "ECDHE-RSA-AES128-GCM-SHA256") ||
      !SSL_set_max_proto_version(ssl.get(), max_version)) {
    return 0;
  }

  std::vector<uint8_t> client_hello;
  if (!GetClientHello(ssl.get(), &client_hello) ||
      client_hello.size() <= SSL3_RT_HEADER_LENGTH) {
    return 0;
  }

  return client_hello.size() - SSL3_RT_HEADER_LENGTH;
}

TEST(SSLTest, Padding) {
  struct PaddingVersions {
    uint16_t max_version, session_version;
  };
  static const PaddingVersions kPaddingVersions[] = {
      // Test the padding extension at TLS 1.2.
      {TLS1_2_VERSION, TLS1_2_VERSION},
      // Test the padding extension at TLS 1.3 with a TLS 1.2 session, so there
      // will be no PSK binder after the padding extension.
      {TLS1_3_VERSION, TLS1_2_VERSION},
      // Test the padding extension at TLS 1.3 with a TLS 1.3 session, so there
      // will be a PSK binder after the padding extension.
      {TLS1_3_VERSION, TLS1_3_VERSION},

  };

  struct PaddingTest {
    size_t input_len, padded_len;
  };
  static const PaddingTest kPaddingTests[] = {
      // ClientHellos of length below 0x100 do not require padding.
      {0xfe, 0xfe},
      {0xff, 0xff},
      // ClientHellos of length 0x100 through 0x1fb are padded up to 0x200.
      {0x100, 0x200},
      {0x123, 0x200},
      {0x1fb, 0x200},
      // ClientHellos of length 0x1fc through 0x1ff get padded beyond 0x200. The
      // padding extension takes a minimum of four bytes plus one required
      // content
      // byte. (To work around yet more server bugs, we avoid empty final
      // extensions.)
      {0x1fc, 0x201},
      {0x1fd, 0x202},
      {0x1fe, 0x203},
      {0x1ff, 0x204},
      // Finally, larger ClientHellos need no padding.
      {0x200, 0x200},
      {0x201, 0x201},
  };

  for (const PaddingVersions &versions : kPaddingVersions) {
    SCOPED_TRACE(versions.max_version);
    SCOPED_TRACE(versions.session_version);

    // Sample a baseline length.
    size_t base_len =
        GetClientHelloLen(versions.max_version, versions.session_version, 1);
    ASSERT_NE(base_len, 0u) << "Baseline length could not be sampled";

    for (const PaddingTest &test : kPaddingTests) {
      SCOPED_TRACE(test.input_len);
      ASSERT_LE(base_len, test.input_len) << "Baseline ClientHello too long";

      size_t padded_len =
          GetClientHelloLen(versions.max_version, versions.session_version,
                            1 + test.input_len - base_len);
      EXPECT_EQ(padded_len, test.padded_len)
          << "ClientHello was not padded to expected length";
    }
  }
}

static bssl::UniquePtr<X509> GetTestCertificate() {
  static const char kCertPEM[] =
      "-----BEGIN CERTIFICATE-----\n"
      "MIICWDCCAcGgAwIBAgIJAPuwTC6rEJsMMA0GCSqGSIb3DQEBBQUAMEUxCzAJBgNV\n"
      "BAYTAkFVMRMwEQYDVQQIDApTb21lLVN0YXRlMSEwHwYDVQQKDBhJbnRlcm5ldCBX\n"
      "aWRnaXRzIFB0eSBMdGQwHhcNMTQwNDIzMjA1MDQwWhcNMTcwNDIyMjA1MDQwWjBF\n"
      "MQswCQYDVQQGEwJBVTETMBEGA1UECAwKU29tZS1TdGF0ZTEhMB8GA1UECgwYSW50\n"
      "ZXJuZXQgV2lkZ2l0cyBQdHkgTHRkMIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKB\n"
      "gQDYK8imMuRi/03z0K1Zi0WnvfFHvwlYeyK9Na6XJYaUoIDAtB92kWdGMdAQhLci\n"
      "HnAjkXLI6W15OoV3gA/ElRZ1xUpxTMhjP6PyY5wqT5r6y8FxbiiFKKAnHmUcrgfV\n"
      "W28tQ+0rkLGMryRtrukXOgXBv7gcrmU7G1jC2a7WqmeI8QIDAQABo1AwTjAdBgNV\n"
      "HQ4EFgQUi3XVrMsIvg4fZbf6Vr5sp3Xaha8wHwYDVR0jBBgwFoAUi3XVrMsIvg4f\n"
      "Zbf6Vr5sp3Xaha8wDAYDVR0TBAUwAwEB/zANBgkqhkiG9w0BAQUFAAOBgQA76Hht\n"
      "ldY9avcTGSwbwoiuIqv0jTL1fHFnzy3RHMLDh+Lpvolc5DSrSJHCP5WuK0eeJXhr\n"
      "T5oQpHL9z/cCDLAKCKRa4uV0fhEdOWBqyR9p8y5jJtye72t6CuFUV5iqcpF4BH4f\n"
      "j2VNHwsSrJwkD4QUGlUtH7vwnQmyCFxZMmWAJg==\n"
      "-----END CERTIFICATE-----\n";
  bssl::UniquePtr<BIO> bio(BIO_new_mem_buf(kCertPEM, strlen(kCertPEM)));
  return bssl::UniquePtr<X509>(
      PEM_read_bio_X509(bio.get(), nullptr, nullptr, nullptr));
}

static bssl::UniquePtr<EVP_PKEY> GetTestKey() {
  static const char kKeyPEM[] =
      "-----BEGIN RSA PRIVATE KEY-----\n"
      "MIICXgIBAAKBgQDYK8imMuRi/03z0K1Zi0WnvfFHvwlYeyK9Na6XJYaUoIDAtB92\n"
      "kWdGMdAQhLciHnAjkXLI6W15OoV3gA/ElRZ1xUpxTMhjP6PyY5wqT5r6y8FxbiiF\n"
      "KKAnHmUcrgfVW28tQ+0rkLGMryRtrukXOgXBv7gcrmU7G1jC2a7WqmeI8QIDAQAB\n"
      "AoGBAIBy09Fd4DOq/Ijp8HeKuCMKTHqTW1xGHshLQ6jwVV2vWZIn9aIgmDsvkjCe\n"
      "i6ssZvnbjVcwzSoByhjN8ZCf/i15HECWDFFh6gt0P5z0MnChwzZmvatV/FXCT0j+\n"
      "WmGNB/gkehKjGXLLcjTb6dRYVJSCZhVuOLLcbWIV10gggJQBAkEA8S8sGe4ezyyZ\n"
      "m4e9r95g6s43kPqtj5rewTsUxt+2n4eVodD+ZUlCULWVNAFLkYRTBCASlSrm9Xhj\n"
      "QpmWAHJUkQJBAOVzQdFUaewLtdOJoPCtpYoY1zd22eae8TQEmpGOR11L6kbxLQsk\n"
      "aMly/DOnOaa82tqAGTdqDEZgSNmCeKKknmECQAvpnY8GUOVAubGR6c+W90iBuQLj\n"
      "LtFp/9ihd2w/PoDwrHZaoUYVcT4VSfJQog/k7kjE4MYXYWL8eEKg3WTWQNECQQDk\n"
      "104Wi91Umd1PzF0ijd2jXOERJU1wEKe6XLkYYNHWQAe5l4J4MWj9OdxFXAxIuuR/\n"
      "tfDwbqkta4xcux67//khAkEAvvRXLHTaa6VFzTaiiO8SaFsHV3lQyXOtMrBpB5jd\n"
      "moZWgjHvB2W9Ckn7sDqsPB+U2tyX0joDdQEyuiMECDY8oQ==\n"
      "-----END RSA PRIVATE KEY-----\n";
  bssl::UniquePtr<BIO> bio(BIO_new_mem_buf(kKeyPEM, strlen(kKeyPEM)));
  return bssl::UniquePtr<EVP_PKEY>(
      PEM_read_bio_PrivateKey(bio.get(), nullptr, nullptr, nullptr));
}

static bssl::UniquePtr<X509> GetECDSATestCertificate() {
  static const char kCertPEM[] =
      "-----BEGIN CERTIFICATE-----\n"
      "MIIBzzCCAXagAwIBAgIJANlMBNpJfb/rMAkGByqGSM49BAEwRTELMAkGA1UEBhMC\n"
      "QVUxEzARBgNVBAgMClNvbWUtU3RhdGUxITAfBgNVBAoMGEludGVybmV0IFdpZGdp\n"
      "dHMgUHR5IEx0ZDAeFw0xNDA0MjMyMzIxNTdaFw0xNDA1MjMyMzIxNTdaMEUxCzAJ\n"
      "BgNVBAYTAkFVMRMwEQYDVQQIDApTb21lLVN0YXRlMSEwHwYDVQQKDBhJbnRlcm5l\n"
      "dCBXaWRnaXRzIFB0eSBMdGQwWTATBgcqhkjOPQIBBggqhkjOPQMBBwNCAATmK2ni\n"
      "v2Wfl74vHg2UikzVl2u3qR4NRvvdqakendy6WgHn1peoChj5w8SjHlbifINI2xYa\n"
      "HPUdfvGULUvPciLBo1AwTjAdBgNVHQ4EFgQUq4TSrKuV8IJOFngHVVdf5CaNgtEw\n"
      "HwYDVR0jBBgwFoAUq4TSrKuV8IJOFngHVVdf5CaNgtEwDAYDVR0TBAUwAwEB/zAJ\n"
      "BgcqhkjOPQQBA0gAMEUCIQDyoDVeUTo2w4J5m+4nUIWOcAZ0lVfSKXQA9L4Vh13E\n"
      "BwIgfB55FGohg/B6dGh5XxSZmmi08cueFV7mHzJSYV51yRQ=\n"
      "-----END CERTIFICATE-----\n";
  bssl::UniquePtr<BIO> bio(BIO_new_mem_buf(kCertPEM, strlen(kCertPEM)));
  return bssl::UniquePtr<X509>(PEM_read_bio_X509(bio.get(), nullptr, nullptr, nullptr));
}

static bssl::UniquePtr<EVP_PKEY> GetECDSATestKey() {
  static const char kKeyPEM[] =
      "-----BEGIN PRIVATE KEY-----\n"
      "MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQgBw8IcnrUoEqc3VnJ\n"
      "TYlodwi1b8ldMHcO6NHJzgqLtGqhRANCAATmK2niv2Wfl74vHg2UikzVl2u3qR4N\n"
      "Rvvdqakendy6WgHn1peoChj5w8SjHlbifINI2xYaHPUdfvGULUvPciLB\n"
      "-----END PRIVATE KEY-----\n";
  bssl::UniquePtr<BIO> bio(BIO_new_mem_buf(kKeyPEM, strlen(kKeyPEM)));
  return bssl::UniquePtr<EVP_PKEY>(
      PEM_read_bio_PrivateKey(bio.get(), nullptr, nullptr, nullptr));
}

static bssl::UniquePtr<CRYPTO_BUFFER> BufferFromPEM(const char *pem) {
  bssl::UniquePtr<BIO> bio(BIO_new_mem_buf(pem, strlen(pem)));
  char *name, *header;
  uint8_t *data;
  long data_len;
  if (!PEM_read_bio(bio.get(), &name, &header, &data,
                    &data_len)) {
    return nullptr;
  }
  OPENSSL_free(name);
  OPENSSL_free(header);

  auto ret = bssl::UniquePtr<CRYPTO_BUFFER>(
      CRYPTO_BUFFER_new(data, data_len, nullptr));
  OPENSSL_free(data);
  return ret;
}

static bssl::UniquePtr<CRYPTO_BUFFER> GetChainTestCertificateBuffer() {
  static const char kCertPEM[] =
      "-----BEGIN CERTIFICATE-----\n"
      "MIIC0jCCAbqgAwIBAgICEAAwDQYJKoZIhvcNAQELBQAwDzENMAsGA1UEAwwEQiBD\n"
      "QTAeFw0xNjAyMjgyMDI3MDNaFw0yNjAyMjUyMDI3MDNaMBgxFjAUBgNVBAMMDUNs\n"
      "aWVudCBDZXJ0IEEwggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQDRvaz8\n"
      "CC/cshpCafJo4jLkHEoBqDLhdgFelJoAiQUyIqyWl2O7YHPnpJH+TgR7oelzNzt/\n"
      "kLRcH89M/TszB6zqyLTC4aqmvzKL0peD/jL2LWBucR0WXIvjA3zoRuF/x86+rYH3\n"
      "tHb+xs2PSs8EGL/Ev+ss+qTzTGEn26fuGNHkNw6tOwPpc+o8+wUtzf/kAthamo+c\n"
      "IDs2rQ+lP7+aLZTLeU/q4gcLutlzcK5imex5xy2jPkweq48kijK0kIzl1cPlA5d1\n"
      "z7C8jU50Pj9X9sQDJTN32j7UYRisJeeYQF8GaaN8SbrDI6zHgKzrRLyxDt/KQa9V\n"
      "iLeXANgZi+Xx9KgfAgMBAAGjLzAtMAwGA1UdEwEB/wQCMAAwHQYDVR0lBBYwFAYI\n"
      "KwYBBQUHAwEGCCsGAQUFBwMCMA0GCSqGSIb3DQEBCwUAA4IBAQBFEVbmYl+2RtNw\n"
      "rDftRDF1v2QUbcN2ouSnQDHxeDQdSgasLzT3ui8iYu0Rw2WWcZ0DV5e0ztGPhWq7\n"
      "AO0B120aFRMOY+4+bzu9Q2FFkQqc7/fKTvTDzIJI5wrMnFvUfzzvxh3OHWMYSs/w\n"
      "giq33hTKeHEq6Jyk3btCny0Ycecyc3yGXH10sizUfiHlhviCkDuESk8mFDwDDzqW\n"
      "ZF0IipzFbEDHoIxLlm3GQxpiLoEV4k8KYJp3R5KBLFyxM6UGPz8h72mIPCJp2RuK\n"
      "MYgF91UDvVzvnYm6TfseM2+ewKirC00GOrZ7rEcFvtxnKSqYf4ckqfNdSU1Y+RRC\n"
      "1ngWZ7Ih\n"
      "-----END CERTIFICATE-----\n";
  return BufferFromPEM(kCertPEM);
}

static bssl::UniquePtr<X509> X509FromBuffer(
    bssl::UniquePtr<CRYPTO_BUFFER> buffer) {
  if (!buffer) {
    return nullptr;
  }
  const uint8_t *derp = CRYPTO_BUFFER_data(buffer.get());
  return bssl::UniquePtr<X509>(
      d2i_X509(NULL, &derp, CRYPTO_BUFFER_len(buffer.get())));
}

static bssl::UniquePtr<X509> GetChainTestCertificate() {
  return X509FromBuffer(GetChainTestCertificateBuffer());
}

static bssl::UniquePtr<CRYPTO_BUFFER> GetChainTestIntermediateBuffer() {
  static const char kCertPEM[] =
      "-----BEGIN CERTIFICATE-----\n"
      "MIICwjCCAaqgAwIBAgICEAEwDQYJKoZIhvcNAQELBQAwFDESMBAGA1UEAwwJQyBS\n"
      "b290IENBMB4XDTE2MDIyODIwMjcwM1oXDTI2MDIyNTIwMjcwM1owDzENMAsGA1UE\n"
      "AwwEQiBDQTCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBALsSCYmDip2D\n"
      "GkjFxw7ykz26JSjELkl6ArlYjFJ3aT/SCh8qbS4gln7RH8CPBd78oFdfhIKQrwtZ\n"
      "3/q21ykD9BAS3qHe2YdcJfm8/kWAy5DvXk6NXU4qX334KofBAEpgdA/igEFq1P1l\n"
      "HAuIfZCpMRfT+i5WohVsGi8f/NgpRvVaMONLNfgw57mz1lbtFeBEISmX0kbsuJxF\n"
      "Qj/Bwhi5/0HAEXG8e7zN4cEx0yPRvmOATRdVb/8dW2pwOHRJq9R5M0NUkIsTSnL7\n"
      "6N/z8hRAHMsV3IudC5Yd7GXW1AGu9a+iKU+Q4xcZCoj0DC99tL4VKujrV1kAeqsM\n"
      "cz5/dKzi6+cCAwEAAaMjMCEwDwYDVR0TAQH/BAUwAwEB/zAOBgNVHQ8BAf8EBAMC\n"
      "AQYwDQYJKoZIhvcNAQELBQADggEBAIIeZiEeNhWWQ8Y4D+AGDwqUUeG8NjCbKrXQ\n"
      "BlHg5wZ8xftFaiP1Dp/UAezmx2LNazdmuwrYB8lm3FVTyaPDTKEGIPS4wJKHgqH1\n"
      "QPDhqNm85ey7TEtI9oYjsNim/Rb+iGkIAMXaxt58SzxbjvP0kMr1JfJIZbic9vye\n"
      "NwIspMFIpP3FB8ywyu0T0hWtCQgL4J47nigCHpOu58deP88fS/Nyz/fyGVWOZ76b\n"
      "WhWwgM3P3X95fQ3d7oFPR/bVh0YV+Cf861INwplokXgXQ3/TCQ+HNXeAMWn3JLWv\n"
      "XFwk8owk9dq/kQGdndGgy3KTEW4ctPX5GNhf3LJ9Q7dLji4ReQ4=\n"
      "-----END CERTIFICATE-----\n";
  return BufferFromPEM(kCertPEM);
}

static bssl::UniquePtr<X509> GetChainTestIntermediate() {
  return X509FromBuffer(GetChainTestIntermediateBuffer());
}

static bssl::UniquePtr<EVP_PKEY> GetChainTestKey() {
  static const char kKeyPEM[] =
      "-----BEGIN PRIVATE KEY-----\n"
      "MIIEvgIBADANBgkqhkiG9w0BAQEFAASCBKgwggSkAgEAAoIBAQDRvaz8CC/cshpC\n"
      "afJo4jLkHEoBqDLhdgFelJoAiQUyIqyWl2O7YHPnpJH+TgR7oelzNzt/kLRcH89M\n"
      "/TszB6zqyLTC4aqmvzKL0peD/jL2LWBucR0WXIvjA3zoRuF/x86+rYH3tHb+xs2P\n"
      "Ss8EGL/Ev+ss+qTzTGEn26fuGNHkNw6tOwPpc+o8+wUtzf/kAthamo+cIDs2rQ+l\n"
      "P7+aLZTLeU/q4gcLutlzcK5imex5xy2jPkweq48kijK0kIzl1cPlA5d1z7C8jU50\n"
      "Pj9X9sQDJTN32j7UYRisJeeYQF8GaaN8SbrDI6zHgKzrRLyxDt/KQa9ViLeXANgZ\n"
      "i+Xx9KgfAgMBAAECggEBAK0VjSJzkyPaamcyTVSWjo7GdaBGcK60lk657RjR+lK0\n"
      "YJ7pkej4oM2hdsVZFsP8Cs4E33nXLa/0pDsRov/qrp0WQm2skwqGMC1I/bZ0WRPk\n"
      "wHaDrBBfESWnJDX/AGpVtlyOjPmgmK6J2usMPihQUDkKdAYrVWJePrMIxt1q6BMe\n"
      "iczs3qriMmtY3bUc4UyUwJ5fhDLjshHvfuIpYQyI6EXZM6dZksn9LylXJnigY6QJ\n"
      "HxOYO0BDwOsZ8yQ8J8afLk88i0GizEkgE1z3REtQUwgWfxr1WV/ud+T6/ZhSAgH9\n"
      "042mQvSFZnIUSEsmCvjhWuAunfxHKCTcAoYISWfzWpkCgYEA7gpf3HHU5Tn+CgUn\n"
      "1X5uGpG3DmcMgfeGgs2r2f/IIg/5Ac1dfYILiybL1tN9zbyLCJfcbFpWBc9hJL6f\n"
      "CPc5hUiwWFJqBJewxQkC1Ae/HakHbip+IZ+Jr0842O4BAArvixk4Lb7/N2Ct9sTE\n"
      "NJO6RtK9lbEZ5uK61DglHy8CS2UCgYEA4ZC1o36kPAMQBggajgnucb2yuUEelk0f\n"
      "AEr+GI32MGE+93xMr7rAhBoqLg4AITyIfEnOSQ5HwagnIHonBbv1LV/Gf9ursx8Z\n"
      "YOGbvT8zzzC+SU1bkDzdjAYnFQVGIjMtKOBJ3K07++ypwX1fr4QsQ8uKL8WSOWwt\n"
      "Z3Bym6XiZzMCgYADnhy+2OwHX85AkLt+PyGlPbmuelpyTzS4IDAQbBa6jcuW/2wA\n"
      "UE2km75VUXmD+u2R/9zVuLm99NzhFhSMqlUxdV1YukfqMfP5yp1EY6m/5aW7QuIP\n"
      "2MDa7TVL9rIFMiVZ09RKvbBbQxjhuzPQKL6X/PPspnhiTefQ+dl2k9xREQKBgHDS\n"
      "fMfGNEeAEKezrfSVqxphE9/tXms3L+ZpnCaT+yu/uEr5dTIAawKoQ6i9f/sf1/Sy\n"
      "xedsqR+IB+oKrzIDDWMgoJybN4pkZ8E5lzhVQIjFjKgFdWLzzqyW9z1gYfABQPlN\n"
      "FiS20WX0vgP1vcKAjdNrHzc9zyHBpgQzDmAj3NZZAoGBAI8vKCKdH7w3aL5CNkZQ\n"
      "2buIeWNA2HZazVwAGG5F2TU/LmXfRKnG6dX5bkU+AkBZh56jNZy//hfFSewJB4Kk\n"
      "buB7ERSdaNbO21zXt9FEA3+z0RfMd/Zv2vlIWOSB5nzl/7UKti3sribK6s9ZVLfi\n"
      "SxpiPQ8d/hmSGwn4ksrWUsJD\n"
      "-----END PRIVATE KEY-----\n";
  bssl::UniquePtr<BIO> bio(BIO_new_mem_buf(kKeyPEM, strlen(kKeyPEM)));
  return bssl::UniquePtr<EVP_PKEY>(
      PEM_read_bio_PrivateKey(bio.get(), nullptr, nullptr, nullptr));
}

// Test that |SSL_get_client_CA_list| echoes back the configured parameter even
// before configuring as a server.
TEST(SSLTest, ClientCAList) {
  bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));
  ASSERT_TRUE(ctx);
  bssl::UniquePtr<SSL> ssl(SSL_new(ctx.get()));
  ASSERT_TRUE(ssl);

  bssl::UniquePtr<X509_NAME> name(X509_NAME_new());
  ASSERT_TRUE(name);

  bssl::UniquePtr<X509_NAME> name_dup(X509_NAME_dup(name.get()));
  ASSERT_TRUE(name_dup);

  bssl::UniquePtr<STACK_OF(X509_NAME)> stack(sk_X509_NAME_new_null());
  ASSERT_TRUE(stack);
  ASSERT_TRUE(PushToStack(stack.get(), std::move(name_dup)));

  // |SSL_set_client_CA_list| takes ownership.
  SSL_set_client_CA_list(ssl.get(), stack.release());

  STACK_OF(X509_NAME) *result = SSL_get_client_CA_list(ssl.get());
  ASSERT_TRUE(result);
  ASSERT_EQ(1u, sk_X509_NAME_num(result));
  EXPECT_EQ(0, X509_NAME_cmp(sk_X509_NAME_value(result, 0), name.get()));
}

TEST(SSLTest, AddClientCA) {
  bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));
  ASSERT_TRUE(ctx);
  bssl::UniquePtr<SSL> ssl(SSL_new(ctx.get()));
  ASSERT_TRUE(ssl);

  bssl::UniquePtr<X509> cert1 = GetTestCertificate();
  bssl::UniquePtr<X509> cert2 = GetChainTestCertificate();
  ASSERT_TRUE(cert1 && cert2);
  X509_NAME *name1 = X509_get_subject_name(cert1.get());
  X509_NAME *name2 = X509_get_subject_name(cert2.get());

  EXPECT_EQ(0u, sk_X509_NAME_num(SSL_get_client_CA_list(ssl.get())));

  ASSERT_TRUE(SSL_add_client_CA(ssl.get(), cert1.get()));
  ASSERT_TRUE(SSL_add_client_CA(ssl.get(), cert2.get()));

  STACK_OF(X509_NAME) *list = SSL_get_client_CA_list(ssl.get());
  ASSERT_EQ(2u, sk_X509_NAME_num(list));
  EXPECT_EQ(0, X509_NAME_cmp(sk_X509_NAME_value(list, 0), name1));
  EXPECT_EQ(0, X509_NAME_cmp(sk_X509_NAME_value(list, 1), name2));

  ASSERT_TRUE(SSL_add_client_CA(ssl.get(), cert1.get()));

  list = SSL_get_client_CA_list(ssl.get());
  ASSERT_EQ(3u, sk_X509_NAME_num(list));
  EXPECT_EQ(0, X509_NAME_cmp(sk_X509_NAME_value(list, 0), name1));
  EXPECT_EQ(0, X509_NAME_cmp(sk_X509_NAME_value(list, 1), name2));
  EXPECT_EQ(0, X509_NAME_cmp(sk_X509_NAME_value(list, 2), name1));
}

static void AppendSession(SSL_SESSION *session, void *arg) {
  std::vector<SSL_SESSION*> *out =
      reinterpret_cast<std::vector<SSL_SESSION*>*>(arg);
  out->push_back(session);
}

// CacheEquals returns true if |ctx|'s session cache consists of |expected|, in
// order.
static bool CacheEquals(SSL_CTX *ctx,
                        const std::vector<SSL_SESSION*> &expected) {
  // Check the linked list.
  SSL_SESSION *ptr = ctx->session_cache_head;
  for (SSL_SESSION *session : expected) {
    if (ptr != session) {
      return false;
    }
    // TODO(davidben): This is an absurd way to denote the end of the list.
    if (ptr->next ==
        reinterpret_cast<SSL_SESSION *>(&ctx->session_cache_tail)) {
      ptr = nullptr;
    } else {
      ptr = ptr->next;
    }
  }
  if (ptr != nullptr) {
    return false;
  }

  // Check the hash table.
  std::vector<SSL_SESSION*> actual, expected_copy;
  lh_SSL_SESSION_doall_arg(ctx->sessions, AppendSession, &actual);
  expected_copy = expected;

  std::sort(actual.begin(), actual.end());
  std::sort(expected_copy.begin(), expected_copy.end());

  return actual == expected_copy;
}

static bssl::UniquePtr<SSL_SESSION> CreateTestSession(uint32_t number) {
  bssl::UniquePtr<SSL_CTX> ssl_ctx(SSL_CTX_new(TLS_method()));
  if (!ssl_ctx) {
    return nullptr;
  }
  bssl::UniquePtr<SSL_SESSION> ret(SSL_SESSION_new(ssl_ctx.get()));
  if (!ret) {
    return nullptr;
  }

  uint8_t id[SSL3_SSL_SESSION_ID_LENGTH] = {0};
  OPENSSL_memcpy(id, &number, sizeof(number));
  if (!SSL_SESSION_set1_id(ret.get(), id, sizeof(id))) {
    return nullptr;
  }
  return ret;
}

// Test that the internal session cache behaves as expected.
TEST(SSLTest, InternalSessionCache) {
  bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));
  ASSERT_TRUE(ctx);

  // Prepare 10 test sessions.
  std::vector<bssl::UniquePtr<SSL_SESSION>> sessions;
  for (int i = 0; i < 10; i++) {
    bssl::UniquePtr<SSL_SESSION> session = CreateTestSession(i);
    ASSERT_TRUE(session);
    sessions.push_back(std::move(session));
  }

  SSL_CTX_sess_set_cache_size(ctx.get(), 5);

  // Insert all the test sessions.
  for (const auto &session : sessions) {
    ASSERT_TRUE(SSL_CTX_add_session(ctx.get(), session.get()));
  }

  // Only the last five should be in the list.
  ASSERT_TRUE(CacheEquals(
      ctx.get(), {sessions[9].get(), sessions[8].get(), sessions[7].get(),
                  sessions[6].get(), sessions[5].get()}));

  // Inserting an element already in the cache should fail and leave the cache
  // unchanged.
  ASSERT_FALSE(SSL_CTX_add_session(ctx.get(), sessions[7].get()));
  ASSERT_TRUE(CacheEquals(
      ctx.get(), {sessions[9].get(), sessions[8].get(), sessions[7].get(),
                  sessions[6].get(), sessions[5].get()}));

  // Although collisions should be impossible (256-bit session IDs), the cache
  // must handle them gracefully.
  bssl::UniquePtr<SSL_SESSION> collision(CreateTestSession(7));
  ASSERT_TRUE(collision);
  ASSERT_TRUE(SSL_CTX_add_session(ctx.get(), collision.get()));
  ASSERT_TRUE(CacheEquals(
      ctx.get(), {collision.get(), sessions[9].get(), sessions[8].get(),
                  sessions[6].get(), sessions[5].get()}));

  // Removing sessions behaves correctly.
  ASSERT_TRUE(SSL_CTX_remove_session(ctx.get(), sessions[6].get()));
  ASSERT_TRUE(CacheEquals(ctx.get(), {collision.get(), sessions[9].get(),
                                      sessions[8].get(), sessions[5].get()}));

  // Removing sessions requires an exact match.
  ASSERT_FALSE(SSL_CTX_remove_session(ctx.get(), sessions[0].get()));
  ASSERT_FALSE(SSL_CTX_remove_session(ctx.get(), sessions[7].get()));

  // The cache remains unchanged.
  ASSERT_TRUE(CacheEquals(ctx.get(), {collision.get(), sessions[9].get(),
                                      sessions[8].get(), sessions[5].get()}));
}

static uint16_t EpochFromSequence(uint64_t seq) {
  return static_cast<uint16_t>(seq >> 48);
}

static const uint8_t kTestName[] = {
    0x30, 0x45, 0x31, 0x0b, 0x30, 0x09, 0x06, 0x03, 0x55, 0x04, 0x06, 0x13,
    0x02, 0x41, 0x55, 0x31, 0x13, 0x30, 0x11, 0x06, 0x03, 0x55, 0x04, 0x08,
    0x0c, 0x0a, 0x53, 0x6f, 0x6d, 0x65, 0x2d, 0x53, 0x74, 0x61, 0x74, 0x65,
    0x31, 0x21, 0x30, 0x1f, 0x06, 0x03, 0x55, 0x04, 0x0a, 0x0c, 0x18, 0x49,
    0x6e, 0x74, 0x65, 0x72, 0x6e, 0x65, 0x74, 0x20, 0x57, 0x69, 0x64, 0x67,
    0x69, 0x74, 0x73, 0x20, 0x50, 0x74, 0x79, 0x20, 0x4c, 0x74, 0x64,
};

static bool CompleteHandshakes(SSL *client, SSL *server) {
  // Drive both their handshakes to completion.
  for (;;) {
    int client_ret = SSL_do_handshake(client);
    int client_err = SSL_get_error(client, client_ret);
    if (client_err != SSL_ERROR_NONE &&
        client_err != SSL_ERROR_WANT_READ &&
        client_err != SSL_ERROR_WANT_WRITE &&
        client_err != SSL_ERROR_PENDING_TICKET) {
      fprintf(stderr, "Client error: %s\n", SSL_error_description(client_err));
      return false;
    }

    int server_ret = SSL_do_handshake(server);
    int server_err = SSL_get_error(server, server_ret);
    if (server_err != SSL_ERROR_NONE &&
        server_err != SSL_ERROR_WANT_READ &&
        server_err != SSL_ERROR_WANT_WRITE &&
        server_err != SSL_ERROR_PENDING_TICKET) {
      fprintf(stderr, "Server error: %s\n", SSL_error_description(server_err));
      return false;
    }

    if (client_ret == 1 && server_ret == 1) {
      break;
    }
  }

  return true;
}

static bool FlushNewSessionTickets(SSL *client, SSL *server) {
  // NewSessionTickets are deferred on the server to |SSL_write|, and clients do
  // not pick them up until |SSL_read|.
  for (;;) {
    int server_ret = SSL_write(server, nullptr, 0);
    int server_err = SSL_get_error(server, server_ret);
    // The server may either succeed (|server_ret| is zero) or block on write
    // (|server_ret| is -1 and |server_err| is |SSL_ERROR_WANT_WRITE|).
    if (server_ret > 0 ||
        (server_ret < 0 && server_err != SSL_ERROR_WANT_WRITE)) {
      fprintf(stderr, "Unexpected server result: %d %d\n", server_ret,
              server_err);
      return false;
    }

    int client_ret = SSL_read(client, nullptr, 0);
    int client_err = SSL_get_error(client, client_ret);
    // The client must always block on read.
    if (client_ret != -1 || client_err != SSL_ERROR_WANT_READ) {
      fprintf(stderr, "Unexpected client result: %d %d\n", client_ret,
              client_err);
      return false;
    }

    // The server flushed everything it had to write.
    if (server_ret == 0) {
      return true;
    }
  }
}

struct ClientConfig {
  SSL_SESSION *session = nullptr;
  std::string servername;
  bool early_data = false;
};

static bool ConnectClientAndServer(bssl::UniquePtr<SSL> *out_client,
                                   bssl::UniquePtr<SSL> *out_server,
                                   SSL_CTX *client_ctx, SSL_CTX *server_ctx,
                                   const ClientConfig &config = ClientConfig(),
                                   bool do_handshake = true,
                                   bool shed_handshake_config = true) {
  bssl::UniquePtr<SSL> client(SSL_new(client_ctx)), server(SSL_new(server_ctx));
  if (!client || !server) {
    return false;
  }
  if (config.early_data) {
    SSL_set_early_data_enabled(client.get(), 1);
  }
  SSL_set_connect_state(client.get());
  SSL_set_accept_state(server.get());

  if (config.session) {
    SSL_set_session(client.get(), config.session);
  }
  if (!config.servername.empty() &&
      !SSL_set_tlsext_host_name(client.get(), config.servername.c_str())) {
    return false;
  }

  BIO *bio1, *bio2;
  if (!BIO_new_bio_pair(&bio1, 0, &bio2, 0)) {
    return false;
  }
  // SSL_set_bio takes ownership.
  SSL_set_bio(client.get(), bio1, bio1);
  SSL_set_bio(server.get(), bio2, bio2);

  SSL_set_shed_handshake_config(client.get(), shed_handshake_config);
  SSL_set_shed_handshake_config(server.get(), shed_handshake_config);

  if (do_handshake && !CompleteHandshakes(client.get(), server.get())) {
    return false;
  }

  *out_client = std::move(client);
  *out_server = std::move(server);
  return true;
}

// SSLVersionTest executes its test cases under all available protocol versions.
// Test cases call |Connect| to create a connection using context objects with
// the protocol version fixed to the current version under test.
class SSLVersionTest : public ::testing::TestWithParam<VersionParam> {
 protected:
  SSLVersionTest() : cert_(GetTestCertificate()), key_(GetTestKey()) {}

  void SetUp() { ResetContexts(); }

  bssl::UniquePtr<SSL_CTX> CreateContext() const {
    const SSL_METHOD *method = is_dtls() ? DTLS_method() : TLS_method();
    bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(method));
    if (!ctx || !SSL_CTX_set_min_proto_version(ctx.get(), version()) ||
        !SSL_CTX_set_max_proto_version(ctx.get(), version())) {
      return nullptr;
    }
    return ctx;
  }

  void ResetContexts() {
    ASSERT_TRUE(cert_);
    ASSERT_TRUE(key_);
    client_ctx_ = CreateContext();
    ASSERT_TRUE(client_ctx_);
    server_ctx_ = CreateContext();
    ASSERT_TRUE(server_ctx_);
    // Set up a server cert. Client certs can be set up explicitly.
    ASSERT_TRUE(UseCertAndKey(server_ctx_.get()));
  }

  bool UseCertAndKey(SSL_CTX *ctx) const {
    return SSL_CTX_use_certificate(ctx, cert_.get()) &&
           SSL_CTX_use_PrivateKey(ctx, key_.get());
  }

  bool Connect(const ClientConfig &config = ClientConfig()) {
    return ConnectClientAndServer(&client_, &server_, client_ctx_.get(),
                                  server_ctx_.get(), config, true,
                                  shed_handshake_config_);
  }

  uint16_t version() const { return GetParam().version; }

  bool is_dtls() const {
    return GetParam().ssl_method == VersionParam::is_dtls;
  }

  bool shed_handshake_config_ = true;
  bssl::UniquePtr<SSL> client_, server_;
  bssl::UniquePtr<SSL_CTX> server_ctx_, client_ctx_;
  bssl::UniquePtr<X509> cert_;
  bssl::UniquePtr<EVP_PKEY> key_;
};

INSTANTIATE_TEST_SUITE_P(WithVersion, SSLVersionTest,
                         testing::ValuesIn(kAllVersions),
                         [](const testing::TestParamInfo<VersionParam> &i) {
                           return i.param.name;
                         });

TEST_P(SSLVersionTest, SequenceNumber) {
  ASSERT_TRUE(Connect());

  // Drain any post-handshake messages to ensure there are no unread records
  // on either end.
  ASSERT_TRUE(FlushNewSessionTickets(client_.get(), server_.get()));

  uint64_t client_read_seq = SSL_get_read_sequence(client_.get());
  uint64_t client_write_seq = SSL_get_write_sequence(client_.get());
  uint64_t server_read_seq = SSL_get_read_sequence(server_.get());
  uint64_t server_write_seq = SSL_get_write_sequence(server_.get());

  if (is_dtls()) {
    // Both client and server must be at epoch 1.
    EXPECT_EQ(EpochFromSequence(client_read_seq), 1);
    EXPECT_EQ(EpochFromSequence(client_write_seq), 1);
    EXPECT_EQ(EpochFromSequence(server_read_seq), 1);
    EXPECT_EQ(EpochFromSequence(server_write_seq), 1);

    // The next record to be written should exceed the largest received.
    EXPECT_GT(client_write_seq, server_read_seq);
    EXPECT_GT(server_write_seq, client_read_seq);
  } else {
    // The next record to be written should equal the next to be received.
    EXPECT_EQ(client_write_seq, server_read_seq);
    EXPECT_EQ(server_write_seq, client_read_seq);
  }

  // Send a record from client to server.
  uint8_t byte = 0;
  EXPECT_EQ(SSL_write(client_.get(), &byte, 1), 1);
  EXPECT_EQ(SSL_read(server_.get(), &byte, 1), 1);

  // The client write and server read sequence numbers should have
  // incremented.
  EXPECT_EQ(client_write_seq + 1, SSL_get_write_sequence(client_.get()));
  EXPECT_EQ(server_read_seq + 1, SSL_get_read_sequence(server_.get()));
}

TEST_P(SSLVersionTest, OneSidedShutdown) {
  // SSL_shutdown is a no-op in DTLS.
  if (is_dtls()) {
    return;
  }
  ASSERT_TRUE(Connect());

  // Shut down half the connection. SSL_shutdown will return 0 to signal only
  // one side has shut down.
  ASSERT_EQ(SSL_shutdown(client_.get()), 0);

  // Reading from the server should consume the EOF.
  uint8_t byte;
  ASSERT_EQ(SSL_read(server_.get(), &byte, 1), 0);
  ASSERT_EQ(SSL_get_error(server_.get(), 0), SSL_ERROR_ZERO_RETURN);

  // However, the server may continue to write data and then shut down the
  // connection.
  byte = 42;
  ASSERT_EQ(SSL_write(server_.get(), &byte, 1), 1);
  ASSERT_EQ(SSL_read(client_.get(), &byte, 1), 1);
  ASSERT_EQ(byte, 42);

  // The server may then shutdown the connection.
  EXPECT_EQ(SSL_shutdown(server_.get()), 1);
  EXPECT_EQ(SSL_shutdown(client_.get()), 1);
}

TEST(SSLTest, SessionDuplication) {
  bssl::UniquePtr<SSL_CTX> client_ctx(SSL_CTX_new(TLS_method()));
  bssl::UniquePtr<SSL_CTX> server_ctx(SSL_CTX_new(TLS_method()));
  ASSERT_TRUE(client_ctx);
  ASSERT_TRUE(server_ctx);

  bssl::UniquePtr<X509> cert = GetTestCertificate();
  bssl::UniquePtr<EVP_PKEY> key = GetTestKey();
  ASSERT_TRUE(cert);
  ASSERT_TRUE(key);
  ASSERT_TRUE(SSL_CTX_use_certificate(server_ctx.get(), cert.get()));
  ASSERT_TRUE(SSL_CTX_use_PrivateKey(server_ctx.get(), key.get()));

  bssl::UniquePtr<SSL> client, server;
  ASSERT_TRUE(ConnectClientAndServer(&client, &server, client_ctx.get(),
                                     server_ctx.get()));

  SSL_SESSION *session0 = SSL_get_session(client.get());
  bssl::UniquePtr<SSL_SESSION> session1 =
      bssl::SSL_SESSION_dup(session0, SSL_SESSION_DUP_ALL);
  ASSERT_TRUE(session1);

  session1->not_resumable = false;

  uint8_t *s0_bytes, *s1_bytes;
  size_t s0_len, s1_len;

  ASSERT_TRUE(SSL_SESSION_to_bytes(session0, &s0_bytes, &s0_len));
  bssl::UniquePtr<uint8_t> free_s0(s0_bytes);

  ASSERT_TRUE(SSL_SESSION_to_bytes(session1.get(), &s1_bytes, &s1_len));
  bssl::UniquePtr<uint8_t> free_s1(s1_bytes);

  EXPECT_EQ(Bytes(s0_bytes, s0_len), Bytes(s1_bytes, s1_len));
}

static void ExpectFDs(const SSL *ssl, int rfd, int wfd) {
  EXPECT_EQ(rfd, SSL_get_fd(ssl));
  EXPECT_EQ(rfd, SSL_get_rfd(ssl));
  EXPECT_EQ(wfd, SSL_get_wfd(ssl));

  // The wrapper BIOs are always equal when fds are equal, even if set
  // individually.
  if (rfd == wfd) {
    EXPECT_EQ(SSL_get_rbio(ssl), SSL_get_wbio(ssl));
  }
}

TEST(SSLTest, SetFD) {
  bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));
  ASSERT_TRUE(ctx);

  // Test setting different read and write FDs.
  bssl::UniquePtr<SSL> ssl(SSL_new(ctx.get()));
  ASSERT_TRUE(ssl);
  EXPECT_TRUE(SSL_set_rfd(ssl.get(), 1));
  EXPECT_TRUE(SSL_set_wfd(ssl.get(), 2));
  ExpectFDs(ssl.get(), 1, 2);

  // Test setting the same FD.
  ssl.reset(SSL_new(ctx.get()));
  ASSERT_TRUE(ssl);
  EXPECT_TRUE(SSL_set_fd(ssl.get(), 1));
  ExpectFDs(ssl.get(), 1, 1);

  // Test setting the same FD one side at a time.
  ssl.reset(SSL_new(ctx.get()));
  ASSERT_TRUE(ssl);
  EXPECT_TRUE(SSL_set_rfd(ssl.get(), 1));
  EXPECT_TRUE(SSL_set_wfd(ssl.get(), 1));
  ExpectFDs(ssl.get(), 1, 1);

  // Test setting the same FD in the other order.
  ssl.reset(SSL_new(ctx.get()));
  ASSERT_TRUE(ssl);
  EXPECT_TRUE(SSL_set_wfd(ssl.get(), 1));
  EXPECT_TRUE(SSL_set_rfd(ssl.get(), 1));
  ExpectFDs(ssl.get(), 1, 1);

  // Test changing the read FD partway through.
  ssl.reset(SSL_new(ctx.get()));
  ASSERT_TRUE(ssl);
  EXPECT_TRUE(SSL_set_fd(ssl.get(), 1));
  EXPECT_TRUE(SSL_set_rfd(ssl.get(), 2));
  ExpectFDs(ssl.get(), 2, 1);

  // Test changing the write FD partway through.
  ssl.reset(SSL_new(ctx.get()));
  ASSERT_TRUE(ssl);
  EXPECT_TRUE(SSL_set_fd(ssl.get(), 1));
  EXPECT_TRUE(SSL_set_wfd(ssl.get(), 2));
  ExpectFDs(ssl.get(), 1, 2);

  // Test a no-op change to the read FD partway through.
  ssl.reset(SSL_new(ctx.get()));
  ASSERT_TRUE(ssl);
  EXPECT_TRUE(SSL_set_fd(ssl.get(), 1));
  EXPECT_TRUE(SSL_set_rfd(ssl.get(), 1));
  ExpectFDs(ssl.get(), 1, 1);

  // Test a no-op change to the write FD partway through.
  ssl.reset(SSL_new(ctx.get()));
  ASSERT_TRUE(ssl);
  EXPECT_TRUE(SSL_set_fd(ssl.get(), 1));
  EXPECT_TRUE(SSL_set_wfd(ssl.get(), 1));
  ExpectFDs(ssl.get(), 1, 1);

  // ASan builds will implicitly test that the internal |BIO| reference-counting
  // is correct.
}

TEST(SSLTest, SetBIO) {
  bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));
  ASSERT_TRUE(ctx);

  bssl::UniquePtr<SSL> ssl(SSL_new(ctx.get()));
  bssl::UniquePtr<BIO> bio1(BIO_new(BIO_s_mem())), bio2(BIO_new(BIO_s_mem())),
      bio3(BIO_new(BIO_s_mem()));
  ASSERT_TRUE(ssl);
  ASSERT_TRUE(bio1);
  ASSERT_TRUE(bio2);
  ASSERT_TRUE(bio3);

  // SSL_set_bio takes one reference when the parameters are the same.
  BIO_up_ref(bio1.get());
  SSL_set_bio(ssl.get(), bio1.get(), bio1.get());

  // Repeating the call does nothing.
  SSL_set_bio(ssl.get(), bio1.get(), bio1.get());

  // It takes one reference each when the parameters are different.
  BIO_up_ref(bio2.get());
  BIO_up_ref(bio3.get());
  SSL_set_bio(ssl.get(), bio2.get(), bio3.get());

  // Repeating the call does nothing.
  SSL_set_bio(ssl.get(), bio2.get(), bio3.get());

  // It takes one reference when changing only wbio.
  BIO_up_ref(bio1.get());
  SSL_set_bio(ssl.get(), bio2.get(), bio1.get());

  // It takes one reference when changing only rbio and the two are different.
  BIO_up_ref(bio3.get());
  SSL_set_bio(ssl.get(), bio3.get(), bio1.get());

  // If setting wbio to rbio, it takes no additional references.
  SSL_set_bio(ssl.get(), bio3.get(), bio3.get());

  // From there, wbio may be switched to something else.
  BIO_up_ref(bio1.get());
  SSL_set_bio(ssl.get(), bio3.get(), bio1.get());

  // If setting rbio to wbio, it takes no additional references.
  SSL_set_bio(ssl.get(), bio1.get(), bio1.get());

  // From there, rbio may be switched to something else, but, for historical
  // reasons, it takes a reference to both parameters.
  BIO_up_ref(bio1.get());
  BIO_up_ref(bio2.get());
  SSL_set_bio(ssl.get(), bio2.get(), bio1.get());

  // ASAN builds will implicitly test that the internal |BIO| reference-counting
  // is correct.
}

static int VerifySucceed(X509_STORE_CTX *store_ctx, void *arg) { return 1; }

TEST_P(SSLVersionTest, GetPeerCertificate) {
  ASSERT_TRUE(UseCertAndKey(client_ctx_.get()));

  // Configure both client and server to accept any certificate.
  SSL_CTX_set_verify(client_ctx_.get(),
                     SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
                     nullptr);
  SSL_CTX_set_cert_verify_callback(client_ctx_.get(), VerifySucceed, NULL);
  SSL_CTX_set_verify(server_ctx_.get(),
                     SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
                     nullptr);
  SSL_CTX_set_cert_verify_callback(server_ctx_.get(), VerifySucceed, NULL);

  ASSERT_TRUE(Connect());

  // Client and server should both see the leaf certificate.
  bssl::UniquePtr<X509> peer(SSL_get_peer_certificate(server_.get()));
  ASSERT_TRUE(peer);
  ASSERT_EQ(X509_cmp(cert_.get(), peer.get()), 0);

  peer.reset(SSL_get_peer_certificate(client_.get()));
  ASSERT_TRUE(peer);
  ASSERT_EQ(X509_cmp(cert_.get(), peer.get()), 0);

  // However, for historical reasons, the X509 chain includes the leaf on the
  // client, but does not on the server.
  EXPECT_EQ(sk_X509_num(SSL_get_peer_cert_chain(client_.get())), 1u);
  EXPECT_EQ(sk_CRYPTO_BUFFER_num(SSL_get0_peer_certificates(client_.get())),
            1u);

  EXPECT_EQ(sk_X509_num(SSL_get_peer_cert_chain(server_.get())), 0u);
  EXPECT_EQ(sk_CRYPTO_BUFFER_num(SSL_get0_peer_certificates(server_.get())),
            1u);
}

TEST_P(SSLVersionTest, NoPeerCertificate) {
  SSL_CTX_set_verify(server_ctx_.get(), SSL_VERIFY_PEER, nullptr);
  SSL_CTX_set_cert_verify_callback(server_ctx_.get(), VerifySucceed, NULL);
  SSL_CTX_set_cert_verify_callback(client_ctx_.get(), VerifySucceed, NULL);

  ASSERT_TRUE(Connect());

  // Server should not see a peer certificate.
  bssl::UniquePtr<X509> peer(SSL_get_peer_certificate(server_.get()));
  ASSERT_FALSE(peer);
  ASSERT_FALSE(SSL_get0_peer_certificates(server_.get()));
}

TEST_P(SSLVersionTest, RetainOnlySHA256OfCerts) {
  uint8_t *cert_der = NULL;
  int cert_der_len = i2d_X509(cert_.get(), &cert_der);
  ASSERT_GE(cert_der_len, 0);
  bssl::UniquePtr<uint8_t> free_cert_der(cert_der);

  uint8_t cert_sha256[SHA256_DIGEST_LENGTH];
  SHA256(cert_der, cert_der_len, cert_sha256);

  ASSERT_TRUE(UseCertAndKey(client_ctx_.get()));

  // Configure both client and server to accept any certificate, but the
  // server must retain only the SHA-256 of the peer.
  SSL_CTX_set_verify(client_ctx_.get(),
                     SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
                     nullptr);
  SSL_CTX_set_verify(server_ctx_.get(),
                     SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
                     nullptr);
  SSL_CTX_set_cert_verify_callback(client_ctx_.get(), VerifySucceed, NULL);
  SSL_CTX_set_cert_verify_callback(server_ctx_.get(), VerifySucceed, NULL);
  SSL_CTX_set_retain_only_sha256_of_client_certs(server_ctx_.get(), 1);

  ASSERT_TRUE(Connect());

  // The peer certificate has been dropped.
  bssl::UniquePtr<X509> peer(SSL_get_peer_certificate(server_.get()));
  EXPECT_FALSE(peer);

  SSL_SESSION *session = SSL_get_session(server_.get());
  EXPECT_TRUE(SSL_SESSION_has_peer_sha256(session));

  const uint8_t *peer_sha256;
  size_t peer_sha256_len;
  SSL_SESSION_get0_peer_sha256(session, &peer_sha256, &peer_sha256_len);
  EXPECT_EQ(Bytes(cert_sha256), Bytes(peer_sha256, peer_sha256_len));
}

// Tests that our ClientHellos do not change unexpectedly. These are purely
// change detection tests. If they fail as part of an intentional ClientHello
// change, update the test vector.
TEST(SSLTest, ClientHello) {
  struct {
    uint16_t max_version;
    std::vector<uint8_t> expected;
  } kTests[] = {
    {TLS1_VERSION,
     {0x16, 0x03, 0x01, 0x00, 0x5a, 0x01, 0x00, 0x00, 0x56, 0x03, 0x01, 0x00,
      0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
      0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
      0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0e, 0xc0, 0x09,
      0xc0, 0x13, 0xc0, 0x0a, 0xc0, 0x14, 0x00, 0x2f, 0x00, 0x35, 0x00, 0x0a,
      0x01, 0x00, 0x00, 0x1f, 0x00, 0x17, 0x00, 0x00, 0xff, 0x01, 0x00, 0x01,
      0x00, 0x00, 0x0a, 0x00, 0x08, 0x00, 0x06, 0x00, 0x1d, 0x00, 0x17, 0x00,
      0x18, 0x00, 0x0b, 0x00, 0x02, 0x01, 0x00, 0x00, 0x23, 0x00, 0x00}},
    {TLS1_1_VERSION,
     {0x16, 0x03, 0x01, 0x00, 0x5a, 0x01, 0x00, 0x00, 0x56, 0x03, 0x02, 0x00,
      0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
      0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
      0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0e, 0xc0, 0x09,
      0xc0, 0x13, 0xc0, 0x0a, 0xc0, 0x14, 0x00, 0x2f, 0x00, 0x35, 0x00, 0x0a,
      0x01, 0x00, 0x00, 0x1f, 0x00, 0x17, 0x00, 0x00, 0xff, 0x01, 0x00, 0x01,
      0x00, 0x00, 0x0a, 0x00, 0x08, 0x00, 0x06, 0x00, 0x1d, 0x00, 0x17, 0x00,
      0x18, 0x00, 0x0b, 0x00, 0x02, 0x01, 0x00, 0x00, 0x23, 0x00, 0x00}},
    {TLS1_2_VERSION,
     {0x16, 0x03, 0x01, 0x00, 0x82, 0x01, 0x00, 0x00, 0x7e, 0x03, 0x03, 0x00,
      0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
      0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
      0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1e, 0xcc, 0xa9,
      0xcc, 0xa8, 0xc0, 0x2b, 0xc0, 0x2f, 0xc0, 0x2c, 0xc0, 0x30, 0xc0, 0x09,
      0xc0, 0x13, 0xc0, 0x0a, 0xc0, 0x14, 0x00, 0x9c, 0x00, 0x9d, 0x00, 0x2f,
      0x00, 0x35, 0x00, 0x0a, 0x01, 0x00, 0x00, 0x37, 0x00, 0x17, 0x00, 0x00,
      0xff, 0x01, 0x00, 0x01, 0x00, 0x00, 0x0a, 0x00, 0x08, 0x00, 0x06, 0x00,
      0x1d, 0x00, 0x17, 0x00, 0x18, 0x00, 0x0b, 0x00, 0x02, 0x01, 0x00, 0x00,
      0x23, 0x00, 0x00, 0x00, 0x0d, 0x00, 0x14, 0x00, 0x12, 0x04, 0x03, 0x08,
      0x04, 0x04, 0x01, 0x05, 0x03, 0x08, 0x05, 0x05, 0x01, 0x08, 0x06, 0x06,
      0x01, 0x02, 0x01}},
    // TODO(davidben): Add a change detector for TLS 1.3 once the spec and our
    // implementation has settled enough that it won't change.
  };

  for (const auto &t : kTests) {
    SCOPED_TRACE(t.max_version);

    bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));
    ASSERT_TRUE(ctx);
    // Our default cipher list varies by CPU capabilities, so manually place the
    // ChaCha20 ciphers in front.
    const char *cipher_list = "CHACHA20:ALL";
    ASSERT_TRUE(SSL_CTX_set_max_proto_version(ctx.get(), t.max_version));
    ASSERT_TRUE(SSL_CTX_set_strict_cipher_list(ctx.get(), cipher_list));

    bssl::UniquePtr<SSL> ssl(SSL_new(ctx.get()));
    ASSERT_TRUE(ssl);
    std::vector<uint8_t> client_hello;
    ASSERT_TRUE(GetClientHello(ssl.get(), &client_hello));

    // Zero the client_random.
    constexpr size_t kRandomOffset = 1 + 2 + 2 +  // record header
                                     1 + 3 +      // handshake message header
                                     2;           // client_version
    ASSERT_GE(client_hello.size(), kRandomOffset + SSL3_RANDOM_SIZE);
    OPENSSL_memset(client_hello.data() + kRandomOffset, 0, SSL3_RANDOM_SIZE);

    if (client_hello != t.expected) {
      ADD_FAILURE() << "ClientHellos did not match.";
      // Print the value manually so it is easier to update the test vector.
      for (size_t i = 0; i < client_hello.size(); i += 12) {
        printf("     %c", i == 0 ? '{' : ' ');
        for (size_t j = i; j < client_hello.size() && j < i + 12; j++) {
          if (j > i) {
            printf(" ");
          }
          printf("0x%02x", client_hello[j]);
          if (j < client_hello.size() - 1) {
            printf(",");
          }
        }
        if (i + 12 >= client_hello.size()) {
          printf("}},");
        }
        printf("\n");
      }
    }
  }
}

static bssl::UniquePtr<SSL_SESSION> g_last_session;

static int SaveLastSession(SSL *ssl, SSL_SESSION *session) {
  // Save the most recent session.
  g_last_session.reset(session);
  return 1;
}

static bssl::UniquePtr<SSL_SESSION> CreateClientSession(
    SSL_CTX *client_ctx, SSL_CTX *server_ctx,
    const ClientConfig &config = ClientConfig()) {
  g_last_session = nullptr;
  SSL_CTX_sess_set_new_cb(client_ctx, SaveLastSession);

  // Connect client and server to get a session.
  bssl::UniquePtr<SSL> client, server;
  if (!ConnectClientAndServer(&client, &server, client_ctx, server_ctx,
                              config) ||
      !FlushNewSessionTickets(client.get(), server.get())) {
    fprintf(stderr, "Failed to connect client and server.\n");
    return nullptr;
  }

  SSL_CTX_sess_set_new_cb(client_ctx, nullptr);

  if (!g_last_session) {
    fprintf(stderr, "Client did not receive a session.\n");
    return nullptr;
  }
  return std::move(g_last_session);
}

static void ExpectSessionReused(SSL_CTX *client_ctx, SSL_CTX *server_ctx,
                                SSL_SESSION *session, bool want_reused) {
  bssl::UniquePtr<SSL> client, server;
  ClientConfig config;
  config.session = session;
  EXPECT_TRUE(
      ConnectClientAndServer(&client, &server, client_ctx, server_ctx, config));

  EXPECT_EQ(SSL_session_reused(client.get()), SSL_session_reused(server.get()));

  bool was_reused = !!SSL_session_reused(client.get());
  EXPECT_EQ(was_reused, want_reused);
}

static bssl::UniquePtr<SSL_SESSION> ExpectSessionRenewed(SSL_CTX *client_ctx,
                                                         SSL_CTX *server_ctx,
                                                         SSL_SESSION *session) {
  g_last_session = nullptr;
  SSL_CTX_sess_set_new_cb(client_ctx, SaveLastSession);

  bssl::UniquePtr<SSL> client, server;
  ClientConfig config;
  config.session = session;
  if (!ConnectClientAndServer(&client, &server, client_ctx, server_ctx,
                              config) ||
      !FlushNewSessionTickets(client.get(), server.get())) {
    fprintf(stderr, "Failed to connect client and server.\n");
    return nullptr;
  }

  if (SSL_session_reused(client.get()) != SSL_session_reused(server.get())) {
    fprintf(stderr, "Client and server were inconsistent.\n");
    return nullptr;
  }

  if (!SSL_session_reused(client.get())) {
    fprintf(stderr, "Session was not reused.\n");
    return nullptr;
  }

  SSL_CTX_sess_set_new_cb(client_ctx, nullptr);

  if (!g_last_session) {
    fprintf(stderr, "Client did not receive a renewed session.\n");
    return nullptr;
  }
  return std::move(g_last_session);
}

static void ExpectTicketKeyChanged(SSL_CTX *ctx, uint8_t *inout_key,
                                   bool changed) {
  uint8_t new_key[kTicketKeyLen];
  // May return 0, 1 or 48.
  ASSERT_EQ(SSL_CTX_get_tlsext_ticket_keys(ctx, new_key, kTicketKeyLen), 1);
  if (changed) {
    ASSERT_NE(Bytes(inout_key, kTicketKeyLen), Bytes(new_key));
  } else {
    ASSERT_EQ(Bytes(inout_key, kTicketKeyLen), Bytes(new_key));
  }
  OPENSSL_memcpy(inout_key, new_key, kTicketKeyLen);
}

static int SwitchSessionIDContextSNI(SSL *ssl, int *out_alert, void *arg) {
  static const uint8_t kContext[] = {3};

  if (!SSL_set_session_id_context(ssl, kContext, sizeof(kContext))) {
    return SSL_TLSEXT_ERR_ALERT_FATAL;
  }

  return SSL_TLSEXT_ERR_OK;
}

TEST_P(SSLVersionTest, SessionIDContext) {
  static const uint8_t kContext1[] = {1};
  static const uint8_t kContext2[] = {2};

  ASSERT_TRUE(SSL_CTX_set_session_id_context(server_ctx_.get(), kContext1,
                                             sizeof(kContext1)));

  SSL_CTX_set_session_cache_mode(client_ctx_.get(), SSL_SESS_CACHE_BOTH);
  SSL_CTX_set_session_cache_mode(server_ctx_.get(), SSL_SESS_CACHE_BOTH);

  bssl::UniquePtr<SSL_SESSION> session =
      CreateClientSession(client_ctx_.get(), server_ctx_.get());
  ASSERT_TRUE(session);

  TRACED_CALL(ExpectSessionReused(client_ctx_.get(), server_ctx_.get(),
                                  session.get(),
                                  true /* expect session reused */));

  // Change the session ID context.
  ASSERT_TRUE(SSL_CTX_set_session_id_context(server_ctx_.get(), kContext2,
                                             sizeof(kContext2)));

  TRACED_CALL(ExpectSessionReused(client_ctx_.get(), server_ctx_.get(),
                                  session.get(),
                                  false /* expect session not reused */));

  // Change the session ID context back and install an SNI callback to switch
  // it.
  ASSERT_TRUE(SSL_CTX_set_session_id_context(server_ctx_.get(), kContext1,
                                             sizeof(kContext1)));

  SSL_CTX_set_tlsext_servername_callback(server_ctx_.get(),
                                         SwitchSessionIDContextSNI);

  TRACED_CALL(ExpectSessionReused(client_ctx_.get(), server_ctx_.get(),
                                  session.get(),
                                  false /* expect session not reused */));

  // Switch the session ID context with the early callback instead.
  SSL_CTX_set_tlsext_servername_callback(server_ctx_.get(), nullptr);
  SSL_CTX_set_select_certificate_cb(
      server_ctx_.get(),
      [](const SSL_CLIENT_HELLO *client_hello) -> ssl_select_cert_result_t {
        static const uint8_t kContext[] = {3};

        if (!SSL_set_session_id_context(client_hello->ssl, kContext,
                                        sizeof(kContext))) {
          return ssl_select_cert_error;
        }

        return ssl_select_cert_success;
      });

  TRACED_CALL(ExpectSessionReused(client_ctx_.get(), server_ctx_.get(),
                                  session.get(),
                                  false /* expect session not reused */));
}

static timeval g_current_time;

static void CurrentTimeCallback(const SSL *ssl, timeval *out_clock) {
  *out_clock = g_current_time;
}

static void FrozenTimeCallback(const SSL *ssl, timeval *out_clock) {
  out_clock->tv_sec = 1000;
  out_clock->tv_usec = 0;
}

static int RenewTicketCallback(SSL *ssl, uint8_t *key_name, uint8_t *iv,
                               EVP_CIPHER_CTX *ctx, HMAC_CTX *hmac_ctx,
                               int encrypt) {
  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;
  }

  // Returning two from the callback in decrypt mode renews the
  // session in TLS 1.2 and below.
  return encrypt ? 1 : 2;
}

static bool GetServerTicketTime(long *out, const SSL_SESSION *session) {
  const uint8_t *ticket;
  size_t ticket_len;
  SSL_SESSION_get0_ticket(session, &ticket, &ticket_len);
  if (ticket_len < 16 + 16 + SHA256_DIGEST_LENGTH) {
    return false;
  }

  const uint8_t *ciphertext = ticket + 16 + 16;
  size_t len = ticket_len - 16 - 16 - SHA256_DIGEST_LENGTH;
  std::unique_ptr<uint8_t[]> plaintext(new uint8_t[len]);

#if defined(BORINGSSL_UNSAFE_FUZZER_MODE)
  // Fuzzer-mode tickets are unencrypted.
  OPENSSL_memcpy(plaintext.get(), ciphertext, len);
#else
  static const uint8_t kZeros[16] = {0};
  const uint8_t *iv = ticket + 16;
  bssl::ScopedEVP_CIPHER_CTX ctx;
  int len1, len2;
  if (!EVP_DecryptInit_ex(ctx.get(), EVP_aes_128_cbc(), nullptr, kZeros, iv) ||
      !EVP_DecryptUpdate(ctx.get(), plaintext.get(), &len1, ciphertext, len) ||
      !EVP_DecryptFinal_ex(ctx.get(), plaintext.get() + len1, &len2)) {
    return false;
  }

  len = static_cast<size_t>(len1 + len2);
#endif

  bssl::UniquePtr<SSL_CTX> ssl_ctx(SSL_CTX_new(TLS_method()));
  if (!ssl_ctx) {
    return false;
  }
  bssl::UniquePtr<SSL_SESSION> server_session(
      SSL_SESSION_from_bytes(plaintext.get(), len, ssl_ctx.get()));
  if (!server_session) {
    return false;
  }

  *out = SSL_SESSION_get_time(server_session.get());
  return true;
}

TEST_P(SSLVersionTest, SessionTimeout) {
  for (bool server_test : {false, true}) {
    SCOPED_TRACE(server_test);

    ResetContexts();
    SSL_CTX_set_session_cache_mode(client_ctx_.get(), SSL_SESS_CACHE_BOTH);
    SSL_CTX_set_session_cache_mode(server_ctx_.get(), SSL_SESS_CACHE_BOTH);

    static const time_t kStartTime = 1000;
    g_current_time.tv_sec = kStartTime;

    // We are willing to use a longer lifetime for TLS 1.3 sessions as
    // resumptions still perform ECDHE.
    const time_t timeout = version() == TLS1_3_VERSION
                               ? SSL_DEFAULT_SESSION_PSK_DHE_TIMEOUT
                               : SSL_DEFAULT_SESSION_TIMEOUT;

    // Both client and server must enforce session timeouts. We configure the
    // other side with a frozen clock so it never expires tickets.
    if (server_test) {
      SSL_CTX_set_current_time_cb(client_ctx_.get(), FrozenTimeCallback);
      SSL_CTX_set_current_time_cb(server_ctx_.get(), CurrentTimeCallback);
    } else {
      SSL_CTX_set_current_time_cb(client_ctx_.get(), CurrentTimeCallback);
      SSL_CTX_set_current_time_cb(server_ctx_.get(), FrozenTimeCallback);
    }

    // Configure a ticket callback which renews tickets.
    SSL_CTX_set_tlsext_ticket_key_cb(server_ctx_.get(), RenewTicketCallback);

    bssl::UniquePtr<SSL_SESSION> session =
        CreateClientSession(client_ctx_.get(), server_ctx_.get());
    ASSERT_TRUE(session);

    // Advance the clock just behind the timeout.
    g_current_time.tv_sec += timeout - 1;

    TRACED_CALL(ExpectSessionReused(client_ctx_.get(), server_ctx_.get(),
                                    session.get(),
                                    true /* expect session reused */));

    // Advance the clock one more second.
    g_current_time.tv_sec++;

    TRACED_CALL(ExpectSessionReused(client_ctx_.get(), server_ctx_.get(),
                                    session.get(),
                                    false /* expect session not reused */));

    // Rewind the clock to before the session was minted.
    g_current_time.tv_sec = kStartTime - 1;

    TRACED_CALL(ExpectSessionReused(client_ctx_.get(), server_ctx_.get(),
                                    session.get(),
                                    false /* expect session not reused */));

    // Renew the session 10 seconds before expiration.
    time_t new_start_time = kStartTime + timeout - 10;
    g_current_time.tv_sec = new_start_time;
    bssl::UniquePtr<SSL_SESSION> new_session = ExpectSessionRenewed(
        client_ctx_.get(), server_ctx_.get(), session.get());
    ASSERT_TRUE(new_session);

    // This new session is not the same object as before.
    EXPECT_NE(session.get(), new_session.get());

    // Check the sessions have timestamps measured from issuance.
    long session_time = 0;
    if (server_test) {
      ASSERT_TRUE(GetServerTicketTime(&session_time, new_session.get()));
    } else {
      session_time = SSL_SESSION_get_time(new_session.get());
    }

    ASSERT_EQ(session_time, g_current_time.tv_sec);

    if (version() == TLS1_3_VERSION) {
      // Renewal incorporates fresh key material in TLS 1.3, so we extend the
      // lifetime TLS 1.3.
      g_current_time.tv_sec = new_start_time + timeout - 1;
      TRACED_CALL(ExpectSessionReused(client_ctx_.get(), server_ctx_.get(),
                                      new_session.get(),
                                      true /* expect session reused */));

      // The new session expires after the new timeout.
      g_current_time.tv_sec = new_start_time + timeout + 1;
      TRACED_CALL(ExpectSessionReused(client_ctx_.get(), server_ctx_.get(),
                                      new_session.get(),
                                      false /* expect session ot reused */));

      // Renew the session until it begins just past the auth timeout.
      time_t auth_end_time = kStartTime + SSL_DEFAULT_SESSION_AUTH_TIMEOUT;
      while (new_start_time < auth_end_time - 1000) {
        // Get as close as possible to target start time.
        new_start_time =
            std::min(auth_end_time - 1000, new_start_time + timeout - 1);
        g_current_time.tv_sec = new_start_time;
        new_session = ExpectSessionRenewed(client_ctx_.get(), server_ctx_.get(),
                                           new_session.get());
        ASSERT_TRUE(new_session);
      }

      // Now the session's lifetime is bound by the auth timeout.
      g_current_time.tv_sec = auth_end_time - 1;
      TRACED_CALL(ExpectSessionReused(client_ctx_.get(), server_ctx_.get(),
                                      new_session.get(),
                                      true /* expect session reused */));

      g_current_time.tv_sec = auth_end_time + 1;
      TRACED_CALL(ExpectSessionReused(client_ctx_.get(), server_ctx_.get(),
                                      new_session.get(),
                                      false /* expect session ot reused */));
    } else {
      // The new session is usable just before the old expiration.
      g_current_time.tv_sec = kStartTime + timeout - 1;
      TRACED_CALL(ExpectSessionReused(client_ctx_.get(), server_ctx_.get(),
                                      new_session.get(),
                                      true /* expect session reused */));

      // Renewal does not extend the lifetime, so it is not usable beyond the
      // old expiration.
      g_current_time.tv_sec = kStartTime + timeout + 1;
      TRACED_CALL(ExpectSessionReused(client_ctx_.get(), server_ctx_.get(),
                                      new_session.get(),
                                      false /* expect session not reused */));
    }
  }
}

TEST_P(SSLVersionTest, DefaultTicketKeyInitialization) {
  static const uint8_t kZeroKey[kTicketKeyLen] = {};
  uint8_t ticket_key[kTicketKeyLen];
  ASSERT_EQ(1, SSL_CTX_get_tlsext_ticket_keys(server_ctx_.get(), ticket_key,
                                              kTicketKeyLen));
  ASSERT_NE(0, OPENSSL_memcmp(ticket_key, kZeroKey, kTicketKeyLen));
}

TEST_P(SSLVersionTest, DefaultTicketKeyRotation) {
  static const time_t kStartTime = 1001;
  g_current_time.tv_sec = kStartTime;

  // We use session reuse as a proxy for ticket decryption success, hence
  // disable session timeouts.
  SSL_CTX_set_timeout(server_ctx_.get(), std::numeric_limits<uint32_t>::max());
  SSL_CTX_set_session_psk_dhe_timeout(server_ctx_.get(),
                                      std::numeric_limits<uint32_t>::max());

  SSL_CTX_set_current_time_cb(client_ctx_.get(), FrozenTimeCallback);
  SSL_CTX_set_current_time_cb(server_ctx_.get(), CurrentTimeCallback);

  SSL_CTX_set_session_cache_mode(client_ctx_.get(), SSL_SESS_CACHE_BOTH);
  SSL_CTX_set_session_cache_mode(server_ctx_.get(), SSL_SESS_CACHE_OFF);

  // Initialize ticket_key with the current key and check that it was
  // initialized to something, not all zeros.
  uint8_t ticket_key[kTicketKeyLen] = {0};
  TRACED_CALL(ExpectTicketKeyChanged(server_ctx_.get(), ticket_key,
                                     true /* changed */));

  // Verify ticket resumption actually works.
  bssl::UniquePtr<SSL> client, server;
  bssl::UniquePtr<SSL_SESSION> session =
      CreateClientSession(client_ctx_.get(), server_ctx_.get());
  ASSERT_TRUE(session);
  TRACED_CALL(ExpectSessionReused(client_ctx_.get(), server_ctx_.get(),
                                  session.get(), true /* reused */));

  // Advance time to just before key rotation.
  g_current_time.tv_sec += SSL_DEFAULT_TICKET_KEY_ROTATION_INTERVAL - 1;
  TRACED_CALL(ExpectSessionReused(client_ctx_.get(), server_ctx_.get(),
                                  session.get(), true /* reused */));
  TRACED_CALL(ExpectTicketKeyChanged(server_ctx_.get(), ticket_key,
                                     false /* NOT changed */));

  // Force key rotation.
  g_current_time.tv_sec += 1;
  bssl::UniquePtr<SSL_SESSION> new_session =
      CreateClientSession(client_ctx_.get(), server_ctx_.get());
  TRACED_CALL(ExpectTicketKeyChanged(server_ctx_.get(), ticket_key,
                                     true /* changed */));

  // Resumption with both old and new ticket should work.
  TRACED_CALL(ExpectSessionReused(client_ctx_.get(), server_ctx_.get(),
                                  session.get(), true /* reused */));
  TRACED_CALL(ExpectSessionReused(client_ctx_.get(), server_ctx_.get(),
                                  new_session.get(), true /* reused */));
  TRACED_CALL(ExpectTicketKeyChanged(server_ctx_.get(), ticket_key,
                                     false /* NOT changed */));

  // Force key rotation again. Resumption with the old ticket now fails.
  g_current_time.tv_sec += SSL_DEFAULT_TICKET_KEY_ROTATION_INTERVAL;
  TRACED_CALL(ExpectSessionReused(client_ctx_.get(), server_ctx_.get(),
                                  session.get(), false /* NOT reused */));
  TRACED_CALL(ExpectTicketKeyChanged(server_ctx_.get(), ticket_key,
                                     true /* changed */));

  // But resumption with the newer session still works.
  TRACED_CALL(ExpectSessionReused(client_ctx_.get(), server_ctx_.get(),
                                  new_session.get(), true /* reused */));
}

static int SwitchContext(SSL *ssl, int *out_alert, void *arg) {
  SSL_CTX *ctx = reinterpret_cast<SSL_CTX *>(arg);
  SSL_set_SSL_CTX(ssl, ctx);
  return SSL_TLSEXT_ERR_OK;
}

TEST_P(SSLVersionTest, SNICallback) {
  bssl::UniquePtr<X509> cert2 = GetECDSATestCertificate();
  ASSERT_TRUE(cert2);
  bssl::UniquePtr<EVP_PKEY> key2 = GetECDSATestKey();
  ASSERT_TRUE(key2);

  // Test that switching the |SSL_CTX| at the SNI callback behaves correctly.
  static const uint16_t kECDSAWithSHA256 = SSL_SIGN_ECDSA_SECP256R1_SHA256;

  static const uint8_t kSCTList[] = {0, 6, 0, 4, 5, 6, 7, 8};
  static const uint8_t kOCSPResponse[] = {1, 2, 3, 4};

  bssl::UniquePtr<SSL_CTX> server_ctx2 = CreateContext();
  ASSERT_TRUE(server_ctx2);
  ASSERT_TRUE(SSL_CTX_use_certificate(server_ctx2.get(), cert2.get()));
  ASSERT_TRUE(SSL_CTX_use_PrivateKey(server_ctx2.get(), key2.get()));
  ASSERT_TRUE(SSL_CTX_set_signed_cert_timestamp_list(
      server_ctx2.get(), kSCTList, sizeof(kSCTList)));
  ASSERT_TRUE(SSL_CTX_set_ocsp_response(server_ctx2.get(), kOCSPResponse,
                                        sizeof(kOCSPResponse)));
  // Historically signing preferences would be lost in some cases with the
  // SNI callback, which triggers the TLS 1.2 SHA-1 default. To ensure
  // this doesn't happen when |version| is TLS 1.2, configure the private
  // key to only sign SHA-256.
  ASSERT_TRUE(SSL_CTX_set_signing_algorithm_prefs(server_ctx2.get(),
                                                  &kECDSAWithSHA256, 1));

  SSL_CTX_set_tlsext_servername_callback(server_ctx_.get(), SwitchContext);
  SSL_CTX_set_tlsext_servername_arg(server_ctx_.get(), server_ctx2.get());

  SSL_CTX_enable_signed_cert_timestamps(client_ctx_.get());
  SSL_CTX_enable_ocsp_stapling(client_ctx_.get());

  ASSERT_TRUE(Connect());

  // The client should have received |cert2|.
  bssl::UniquePtr<X509> peer(SSL_get_peer_certificate(client_.get()));
  ASSERT_TRUE(peer);
  EXPECT_EQ(X509_cmp(peer.get(), cert2.get()), 0);

  // The client should have received |server_ctx2|'s SCT list.
  const uint8_t *data;
  size_t len;
  SSL_get0_signed_cert_timestamp_list(client_.get(), &data, &len);
  EXPECT_EQ(Bytes(kSCTList), Bytes(data, len));

  // The client should have received |server_ctx2|'s OCSP response.
  SSL_get0_ocsp_response(client_.get(), &data, &len);
  EXPECT_EQ(Bytes(kOCSPResponse), Bytes(data, len));
}

// Test that the early callback can swap the maximum version.
TEST(SSLTest, EarlyCallbackVersionSwitch) {
  bssl::UniquePtr<X509> cert = GetTestCertificate();
  bssl::UniquePtr<EVP_PKEY> key = GetTestKey();
  bssl::UniquePtr<SSL_CTX> server_ctx(SSL_CTX_new(TLS_method()));
  bssl::UniquePtr<SSL_CTX> client_ctx(SSL_CTX_new(TLS_method()));
  ASSERT_TRUE(cert);
  ASSERT_TRUE(key);
  ASSERT_TRUE(server_ctx);
  ASSERT_TRUE(client_ctx);
  ASSERT_TRUE(SSL_CTX_use_certificate(server_ctx.get(), cert.get()));
  ASSERT_TRUE(SSL_CTX_use_PrivateKey(server_ctx.get(), key.get()));
  ASSERT_TRUE(SSL_CTX_set_max_proto_version(client_ctx.get(), TLS1_3_VERSION));
  ASSERT_TRUE(SSL_CTX_set_max_proto_version(server_ctx.get(), TLS1_3_VERSION));

  SSL_CTX_set_select_certificate_cb(
      server_ctx.get(),
      [](const SSL_CLIENT_HELLO *client_hello) -> ssl_select_cert_result_t {
        if (!SSL_set_max_proto_version(client_hello->ssl, TLS1_2_VERSION)) {
          return ssl_select_cert_error;
        }

        return ssl_select_cert_success;
      });

  bssl::UniquePtr<SSL> client, server;
  ASSERT_TRUE(ConnectClientAndServer(&client, &server, client_ctx.get(),
                                     server_ctx.get()));
  EXPECT_EQ(TLS1_2_VERSION, SSL_version(client.get()));
}

TEST(SSLTest, SetVersion) {
  bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));
  ASSERT_TRUE(ctx);

  // Set valid TLS versions.
  EXPECT_TRUE(SSL_CTX_set_max_proto_version(ctx.get(), TLS1_VERSION));
  EXPECT_TRUE(SSL_CTX_set_max_proto_version(ctx.get(), TLS1_1_VERSION));
  EXPECT_TRUE(SSL_CTX_set_min_proto_version(ctx.get(), TLS1_VERSION));
  EXPECT_TRUE(SSL_CTX_set_min_proto_version(ctx.get(), TLS1_1_VERSION));

  // Invalid TLS versions are rejected.
  EXPECT_FALSE(SSL_CTX_set_max_proto_version(ctx.get(), DTLS1_VERSION));
  EXPECT_FALSE(SSL_CTX_set_max_proto_version(ctx.get(), 0x0200));
  EXPECT_FALSE(SSL_CTX_set_max_proto_version(ctx.get(), 0x1234));
  EXPECT_FALSE(SSL_CTX_set_min_proto_version(ctx.get(), DTLS1_VERSION));
  EXPECT_FALSE(SSL_CTX_set_min_proto_version(ctx.get(), 0x0200));
  EXPECT_FALSE(SSL_CTX_set_min_proto_version(ctx.get(), 0x1234));

  // Zero is the default version.
  EXPECT_TRUE(SSL_CTX_set_max_proto_version(ctx.get(), 0));
  EXPECT_EQ(TLS1_3_VERSION, SSL_CTX_get_max_proto_version(ctx.get()));
  EXPECT_TRUE(SSL_CTX_set_min_proto_version(ctx.get(), 0));
  EXPECT_EQ(TLS1_VERSION, SSL_CTX_get_min_proto_version(ctx.get()));

  // TLS 1.3 is available, but not by default.
  EXPECT_TRUE(SSL_CTX_set_max_proto_version(ctx.get(), TLS1_3_VERSION));
  EXPECT_EQ(TLS1_3_VERSION, SSL_CTX_get_max_proto_version(ctx.get()));

  // SSL 3.0 is not available.
  EXPECT_FALSE(SSL_CTX_set_min_proto_version(ctx.get(), SSL3_VERSION));

  ctx.reset(SSL_CTX_new(DTLS_method()));
  ASSERT_TRUE(ctx);

  EXPECT_TRUE(SSL_CTX_set_max_proto_version(ctx.get(), DTLS1_VERSION));
  EXPECT_TRUE(SSL_CTX_set_max_proto_version(ctx.get(), DTLS1_2_VERSION));
  EXPECT_TRUE(SSL_CTX_set_min_proto_version(ctx.get(), DTLS1_VERSION));
  EXPECT_TRUE(SSL_CTX_set_min_proto_version(ctx.get(), DTLS1_2_VERSION));

  EXPECT_FALSE(SSL_CTX_set_max_proto_version(ctx.get(), TLS1_VERSION));
  EXPECT_FALSE(SSL_CTX_set_max_proto_version(ctx.get(), 0xfefe /* DTLS 1.1 */));
  EXPECT_FALSE(SSL_CTX_set_max_proto_version(ctx.get(), 0xfffe /* DTLS 0.1 */));
  EXPECT_FALSE(SSL_CTX_set_max_proto_version(ctx.get(), 0x1234));
  EXPECT_FALSE(SSL_CTX_set_min_proto_version(ctx.get(), TLS1_VERSION));
  EXPECT_FALSE(SSL_CTX_set_min_proto_version(ctx.get(), 0xfefe /* DTLS 1.1 */));
  EXPECT_FALSE(SSL_CTX_set_min_proto_version(ctx.get(), 0xfffe /* DTLS 0.1 */));
  EXPECT_FALSE(SSL_CTX_set_min_proto_version(ctx.get(), 0x1234));

  EXPECT_TRUE(SSL_CTX_set_max_proto_version(ctx.get(), 0));
  EXPECT_EQ(DTLS1_2_VERSION, SSL_CTX_get_max_proto_version(ctx.get()));
  EXPECT_TRUE(SSL_CTX_set_min_proto_version(ctx.get(), 0));
  EXPECT_EQ(DTLS1_VERSION, SSL_CTX_get_min_proto_version(ctx.get()));
}

static const char *GetVersionName(uint16_t version) {
  switch (version) {
    case TLS1_VERSION:
      return "TLSv1";
    case TLS1_1_VERSION:
      return "TLSv1.1";
    case TLS1_2_VERSION:
      return "TLSv1.2";
    case TLS1_3_VERSION:
      return "TLSv1.3";
    case DTLS1_VERSION:
      return "DTLSv1";
    case DTLS1_2_VERSION:
      return "DTLSv1.2";
    default:
      return "???";
  }
}

TEST_P(SSLVersionTest, Version) {
  ASSERT_TRUE(Connect());

  EXPECT_EQ(SSL_version(client_.get()), version());
  EXPECT_EQ(SSL_version(server_.get()), version());

  // Test the version name is reported as expected.
  const char *version_name = GetVersionName(version());
  EXPECT_EQ(strcmp(version_name, SSL_get_version(client_.get())), 0);
  EXPECT_EQ(strcmp(version_name, SSL_get_version(server_.get())), 0);

  // Test SSL_SESSION reports the same name.
  const char *client_name =
      SSL_SESSION_get_version(SSL_get_session(client_.get()));
  const char *server_name =
      SSL_SESSION_get_version(SSL_get_session(server_.get()));
  EXPECT_EQ(strcmp(version_name, client_name), 0);
  EXPECT_EQ(strcmp(version_name, server_name), 0);
}

// Tests that that |SSL_get_pending_cipher| is available during the ALPN
// selection callback.
TEST_P(SSLVersionTest, ALPNCipherAvailable) {
  ASSERT_TRUE(UseCertAndKey(client_ctx_.get()));

  static const uint8_t kALPNProtos[] = {0x03, 'f', 'o', 'o'};
  ASSERT_EQ(SSL_CTX_set_alpn_protos(client_ctx_.get(), kALPNProtos,
                                    sizeof(kALPNProtos)),
            0);

  // The ALPN callback does not fail the handshake on error, so have the
  // callback write a boolean.
  std::pair<uint16_t, bool> callback_state(version(), false);
  SSL_CTX_set_alpn_select_cb(
      server_ctx_.get(),
      [](SSL *ssl, const uint8_t **out, uint8_t *out_len, const uint8_t *in,
         unsigned in_len, void *arg) -> int {
        auto state = reinterpret_cast<std::pair<uint16_t, bool> *>(arg);
        if (SSL_get_pending_cipher(ssl) != nullptr &&
            SSL_version(ssl) == state->first) {
          state->second = true;
        }
        return SSL_TLSEXT_ERR_NOACK;
      },
      &callback_state);

  ASSERT_TRUE(Connect());

  ASSERT_TRUE(callback_state.second);
}

TEST_P(SSLVersionTest, SSLClearSessionResumption) {
  // Skip this for TLS 1.3. TLS 1.3's ticket mechanism is incompatible with this
  // API pattern.
  if (version() == TLS1_3_VERSION) {
    return;
  }

  shed_handshake_config_ = false;
  ASSERT_TRUE(Connect());

  EXPECT_FALSE(SSL_session_reused(client_.get()));
  EXPECT_FALSE(SSL_session_reused(server_.get()));

  // Reset everything.
  ASSERT_TRUE(SSL_clear(client_.get()));
  ASSERT_TRUE(SSL_clear(server_.get()));

  // Attempt to connect a second time.
  ASSERT_TRUE(CompleteHandshakes(client_.get(), server_.get()));

  // |SSL_clear| should implicitly offer the previous session to the server.
  EXPECT_TRUE(SSL_session_reused(client_.get()));
  EXPECT_TRUE(SSL_session_reused(server_.get()));
}

TEST_P(SSLVersionTest, SSLClearFailsWithShedding) {
  shed_handshake_config_ = false;
  ASSERT_TRUE(Connect());
  ASSERT_TRUE(CompleteHandshakes(client_.get(), server_.get()));

  // Reset everything.
  ASSERT_TRUE(SSL_clear(client_.get()));
  ASSERT_TRUE(SSL_clear(server_.get()));

  // Now enable shedding, and connect a second time.
  shed_handshake_config_ = true;
  ASSERT_TRUE(Connect());
  ASSERT_TRUE(CompleteHandshakes(client_.get(), server_.get()));

  // |SSL_clear| should now fail.
  ASSERT_FALSE(SSL_clear(client_.get()));
  ASSERT_FALSE(SSL_clear(server_.get()));
}

static bool ChainsEqual(STACK_OF(X509) * chain,
                        const std::vector<X509 *> &expected) {
  if (sk_X509_num(chain) != expected.size()) {
    return false;
  }

  for (size_t i = 0; i < expected.size(); i++) {
    if (X509_cmp(sk_X509_value(chain, i), expected[i]) != 0) {
      return false;
    }
  }

  return true;
}

TEST_P(SSLVersionTest, AutoChain) {
  cert_ = GetChainTestCertificate();
  ASSERT_TRUE(cert_);
  key_ = GetChainTestKey();
  ASSERT_TRUE(key_);
  bssl::UniquePtr<X509> intermediate = GetChainTestIntermediate();
  ASSERT_TRUE(intermediate);

  ASSERT_TRUE(UseCertAndKey(client_ctx_.get()));
  ASSERT_TRUE(UseCertAndKey(server_ctx_.get()));

  // Configure both client and server to accept any certificate. Add
  // |intermediate| to the cert store.
  ASSERT_TRUE(X509_STORE_add_cert(SSL_CTX_get_cert_store(client_ctx_.get()),
                                  intermediate.get()));
  ASSERT_TRUE(X509_STORE_add_cert(SSL_CTX_get_cert_store(server_ctx_.get()),
                                  intermediate.get()));
  SSL_CTX_set_verify(client_ctx_.get(),
                     SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
                     nullptr);
  SSL_CTX_set_verify(server_ctx_.get(),
                     SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
                     nullptr);
  SSL_CTX_set_cert_verify_callback(client_ctx_.get(), VerifySucceed, NULL);
  SSL_CTX_set_cert_verify_callback(server_ctx_.get(), VerifySucceed, NULL);

  // By default, the client and server should each only send the leaf.
  ASSERT_TRUE(Connect());

  EXPECT_TRUE(
      ChainsEqual(SSL_get_peer_full_cert_chain(client_.get()), {cert_.get()}));
  EXPECT_TRUE(
      ChainsEqual(SSL_get_peer_full_cert_chain(server_.get()), {cert_.get()}));

  // If auto-chaining is enabled, then the intermediate is sent.
  SSL_CTX_clear_mode(client_ctx_.get(), SSL_MODE_NO_AUTO_CHAIN);
  SSL_CTX_clear_mode(server_ctx_.get(), SSL_MODE_NO_AUTO_CHAIN);
  ASSERT_TRUE(Connect());

  EXPECT_TRUE(ChainsEqual(SSL_get_peer_full_cert_chain(client_.get()),
                          {cert_.get(), intermediate.get()}));
  EXPECT_TRUE(ChainsEqual(SSL_get_peer_full_cert_chain(server_.get()),
                          {cert_.get(), intermediate.get()}));

  // Auto-chaining does not override explicitly-configured intermediates.
  ASSERT_TRUE(SSL_CTX_add1_chain_cert(client_ctx_.get(), cert_.get()));
  ASSERT_TRUE(SSL_CTX_add1_chain_cert(server_ctx_.get(), cert_.get()));
  ASSERT_TRUE(Connect());

  EXPECT_TRUE(ChainsEqual(SSL_get_peer_full_cert_chain(client_.get()),
                          {cert_.get(), cert_.get()}));

  EXPECT_TRUE(ChainsEqual(SSL_get_peer_full_cert_chain(server_.get()),
                          {cert_.get(), cert_.get()}));
}

static bool ExpectBadWriteRetry() {
  int err = ERR_get_error();
  if (ERR_GET_LIB(err) != ERR_LIB_SSL ||
      ERR_GET_REASON(err) != SSL_R_BAD_WRITE_RETRY) {
    char buf[ERR_ERROR_STRING_BUF_LEN];
    ERR_error_string_n(err, buf, sizeof(buf));
    fprintf(stderr, "Wanted SSL_R_BAD_WRITE_RETRY, got: %s.\n", buf);
    return false;
  }

  if (ERR_peek_error() != 0) {
    fprintf(stderr, "Unexpected error following SSL_R_BAD_WRITE_RETRY.\n");
    return false;
  }

  return true;
}

TEST_P(SSLVersionTest, SSLWriteRetry) {
  if (is_dtls()) {
    return;
  }

  for (bool enable_partial_write : {false, true}) {
    SCOPED_TRACE(enable_partial_write);

    // Connect a client and server.
    ASSERT_TRUE(UseCertAndKey(client_ctx_.get()));

    ASSERT_TRUE(Connect());

    if (enable_partial_write) {
      SSL_set_mode(client_.get(), SSL_MODE_ENABLE_PARTIAL_WRITE);
    }

    // Write without reading until the buffer is full and we have an unfinished
    // write. Keep a count so we may reread it again later. "hello!" will be
    // written in two chunks, "hello" and "!".
    char data[] = "hello!";
    static const int kChunkLen = 5;  // The length of "hello".
    unsigned count = 0;
    for (;;) {
      int ret = SSL_write(client_.get(), data, kChunkLen);
      if (ret <= 0) {
        ASSERT_EQ(SSL_get_error(client_.get(), ret), SSL_ERROR_WANT_WRITE);
        break;
      }

      ASSERT_EQ(ret, 5);

      count++;
    }

    // Retrying with the same parameters is legal.
    ASSERT_EQ(
        SSL_get_error(client_.get(), SSL_write(client_.get(), data, kChunkLen)),
        SSL_ERROR_WANT_WRITE);

    // Retrying with the same buffer but shorter length is not legal.
    ASSERT_EQ(SSL_get_error(client_.get(),
                            SSL_write(client_.get(), data, kChunkLen - 1)),
              SSL_ERROR_SSL);
    ASSERT_TRUE(ExpectBadWriteRetry());

    // Retrying with a different buffer pointer is not legal.
    char data2[] = "hello";
    ASSERT_EQ(SSL_get_error(client_.get(),
                            SSL_write(client_.get(), data2, kChunkLen)),
              SSL_ERROR_SSL);
    ASSERT_TRUE(ExpectBadWriteRetry());

    // With |SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER|, the buffer may move.
    SSL_set_mode(client_.get(), SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
    ASSERT_EQ(SSL_get_error(client_.get(),
                            SSL_write(client_.get(), data2, kChunkLen)),
              SSL_ERROR_WANT_WRITE);

    // |SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER| does not disable length checks.
    ASSERT_EQ(SSL_get_error(client_.get(),
                            SSL_write(client_.get(), data2, kChunkLen - 1)),
              SSL_ERROR_SSL);
    ASSERT_TRUE(ExpectBadWriteRetry());

    // Retrying with a larger buffer is legal.
    ASSERT_EQ(SSL_get_error(client_.get(),
                            SSL_write(client_.get(), data, kChunkLen + 1)),
              SSL_ERROR_WANT_WRITE);

    // Drain the buffer.
    char buf[20];
    for (unsigned i = 0; i < count; i++) {
      ASSERT_EQ(SSL_read(server_.get(), buf, sizeof(buf)), kChunkLen);
      ASSERT_EQ(OPENSSL_memcmp(buf, "hello", kChunkLen), 0);
    }

    // Now that there is space, a retry with a larger buffer should flush the
    // pending record, skip over that many bytes of input (on assumption they
    // are the same), and write the remainder. If SSL_MODE_ENABLE_PARTIAL_WRITE
    // is set, this will complete in two steps.
    char data3[] = "_____!";
    if (enable_partial_write) {
      ASSERT_EQ(SSL_write(client_.get(), data3, kChunkLen + 1), kChunkLen);
      ASSERT_EQ(SSL_write(client_.get(), data3 + kChunkLen, 1), 1);
    } else {
      ASSERT_EQ(SSL_write(client_.get(), data3, kChunkLen + 1), kChunkLen + 1);
    }

    // Check the last write was correct. The data will be spread over two
    // records, so SSL_read returns twice.
    ASSERT_EQ(SSL_read(server_.get(), buf, sizeof(buf)), kChunkLen);
    ASSERT_EQ(OPENSSL_memcmp(buf, "hello", kChunkLen), 0);
    ASSERT_EQ(SSL_read(server_.get(), buf, sizeof(buf)), 1);
    ASSERT_EQ(buf[0], '!');
  }
}

TEST_P(SSLVersionTest, RecordCallback) {
  for (bool test_server : {true, false}) {
    SCOPED_TRACE(test_server);
    ResetContexts();

    bool read_seen = false;
    bool write_seen = false;
    auto cb = [&](int is_write, int cb_version, int cb_type, const void *buf,
                  size_t len, SSL *ssl) {
      if (cb_type != SSL3_RT_HEADER) {
        return;
      }

      // The callback does not report a version for records.
      EXPECT_EQ(0, cb_version);

      if (is_write) {
        write_seen = true;
      } else {
        read_seen = true;
      }

      // Sanity-check that the record header is plausible.
      CBS cbs;
      CBS_init(&cbs, reinterpret_cast<const uint8_t *>(buf), len);
      uint8_t type;
      uint16_t record_version, length;
      ASSERT_TRUE(CBS_get_u8(&cbs, &type));
      ASSERT_TRUE(CBS_get_u16(&cbs, &record_version));
      EXPECT_EQ(record_version & 0xff00, version() & 0xff00);
      if (is_dtls()) {
        uint16_t epoch;
        ASSERT_TRUE(CBS_get_u16(&cbs, &epoch));
        EXPECT_TRUE(epoch == 0 || epoch == 1) << "Invalid epoch: " << epoch;
        ASSERT_TRUE(CBS_skip(&cbs, 6));
      }
      ASSERT_TRUE(CBS_get_u16(&cbs, &length));
      EXPECT_EQ(0u, CBS_len(&cbs));
    };
    using CallbackType = decltype(cb);
    SSL_CTX *ctx = test_server ? server_ctx_.get() : client_ctx_.get();
    SSL_CTX_set_msg_callback(
        ctx, [](int is_write, int cb_version, int cb_type, const void *buf,
                size_t len, SSL *ssl, void *arg) {
          CallbackType *cb_ptr = reinterpret_cast<CallbackType *>(arg);
          (*cb_ptr)(is_write, cb_version, cb_type, buf, len, ssl);
        });
    SSL_CTX_set_msg_callback_arg(ctx, &cb);

    ASSERT_TRUE(Connect());

    EXPECT_TRUE(read_seen);
    EXPECT_TRUE(write_seen);
  }
}

TEST_P(SSLVersionTest, GetServerName) {
  ClientConfig config;
  config.servername = "host1";

  SSL_CTX_set_tlsext_servername_callback(
      server_ctx_.get(), [](SSL *ssl, int *out_alert, void *arg) -> int {
        // During the handshake, |SSL_get_servername| must match |config|.
        ClientConfig *config_p = reinterpret_cast<ClientConfig *>(arg);
        EXPECT_STREQ(config_p->servername.c_str(),
                     SSL_get_servername(ssl, TLSEXT_NAMETYPE_host_name));
        return SSL_TLSEXT_ERR_OK;
      });
  SSL_CTX_set_tlsext_servername_arg(server_ctx_.get(), &config);

  ASSERT_TRUE(Connect(config));
  // After the handshake, it must also be available.
  EXPECT_STREQ(config.servername.c_str(),
               SSL_get_servername(server_.get(), TLSEXT_NAMETYPE_host_name));

  // Establish a session under host1.
  SSL_CTX_set_session_cache_mode(client_ctx_.get(), SSL_SESS_CACHE_BOTH);
  SSL_CTX_set_session_cache_mode(server_ctx_.get(), SSL_SESS_CACHE_BOTH);
  bssl::UniquePtr<SSL_SESSION> session =
      CreateClientSession(client_ctx_.get(), server_ctx_.get(), config);

  // If the client resumes a session with a different name, |SSL_get_servername|
  // must return the new name.
  ASSERT_TRUE(session);
  config.session = session.get();
  config.servername = "host2";
  ASSERT_TRUE(Connect(config));
  EXPECT_STREQ(config.servername.c_str(),
               SSL_get_servername(server_.get(), TLSEXT_NAMETYPE_host_name));
}

// Test that session cache mode bits are honored in the client session callback.
TEST_P(SSLVersionTest, ClientSessionCacheMode) {
  SSL_CTX_set_session_cache_mode(client_ctx_.get(), SSL_SESS_CACHE_OFF);
  EXPECT_FALSE(CreateClientSession(client_ctx_.get(), server_ctx_.get()));

  SSL_CTX_set_session_cache_mode(client_ctx_.get(), SSL_SESS_CACHE_CLIENT);
  EXPECT_TRUE(CreateClientSession(client_ctx_.get(), server_ctx_.get()));

  SSL_CTX_set_session_cache_mode(client_ctx_.get(), SSL_SESS_CACHE_SERVER);
  EXPECT_FALSE(CreateClientSession(client_ctx_.get(), server_ctx_.get()));
}

// Test that all versions survive tiny write buffers. In particular, TLS 1.3
// NewSessionTickets are written post-handshake. Servers that block
// |SSL_do_handshake| on writing them will deadlock if clients are not draining
// the buffer. Test that we do not do this.
TEST_P(SSLVersionTest, SmallBuffer) {
  // DTLS is a datagram protocol and requires packet-sized buffers.
  if (is_dtls()) {
    return;
  }

  // Test both flushing NewSessionTickets with a zero-sized write and
  // non-zero-sized write.
  for (bool use_zero_write : {false, true}) {
    SCOPED_TRACE(use_zero_write);

    g_last_session = nullptr;
    SSL_CTX_set_session_cache_mode(client_ctx_.get(), SSL_SESS_CACHE_BOTH);
    SSL_CTX_sess_set_new_cb(client_ctx_.get(), SaveLastSession);

    bssl::UniquePtr<SSL> client(SSL_new(client_ctx_.get())),
        server(SSL_new(server_ctx_.get()));
    ASSERT_TRUE(client);
    ASSERT_TRUE(server);
    SSL_set_connect_state(client.get());
    SSL_set_accept_state(server.get());

    // Use a tiny buffer.
    BIO *bio1, *bio2;
    ASSERT_TRUE(BIO_new_bio_pair(&bio1, 1, &bio2, 1));

    // SSL_set_bio takes ownership.
    SSL_set_bio(client.get(), bio1, bio1);
    SSL_set_bio(server.get(), bio2, bio2);

    ASSERT_TRUE(CompleteHandshakes(client.get(), server.get()));
    if (version() >= TLS1_3_VERSION) {
      // The post-handshake ticket should not have been processed yet.
      EXPECT_FALSE(g_last_session);
    }

    if (use_zero_write) {
      ASSERT_TRUE(FlushNewSessionTickets(client.get(), server.get()));
      EXPECT_TRUE(g_last_session);
    }

    // Send some data from server to client. If |use_zero_write| is false, this
    // will also flush the NewSessionTickets.
    static const char kMessage[] = "hello world";
    char buf[sizeof(kMessage)];
    for (;;) {
      int server_ret = SSL_write(server.get(), kMessage, sizeof(kMessage));
      int server_err = SSL_get_error(server.get(), server_ret);
      int client_ret = SSL_read(client.get(), buf, sizeof(buf));
      int client_err = SSL_get_error(client.get(), client_ret);

      // The server will write a single record, so every iteration should see
      // |SSL_ERROR_WANT_WRITE| and |SSL_ERROR_WANT_READ|, until the final
      // iteration, where both will complete.
      if (server_ret > 0) {
        EXPECT_EQ(server_ret, static_cast<int>(sizeof(kMessage)));
        EXPECT_EQ(client_ret, static_cast<int>(sizeof(kMessage)));
        EXPECT_EQ(Bytes(buf), Bytes(kMessage));
        break;
      }

      ASSERT_EQ(server_ret, -1);
      ASSERT_EQ(server_err, SSL_ERROR_WANT_WRITE);
      ASSERT_EQ(client_ret, -1);
      ASSERT_EQ(client_err, SSL_ERROR_WANT_READ);
    }

    // The NewSessionTickets should have been flushed and processed.
    EXPECT_TRUE(g_last_session);
  }
}

TEST(SSLTest, AddChainCertHack) {
  // Ensure that we don't accidently break the hack that we have in place to
  // keep curl and serf happy when they use an |X509| even after transfering
  // ownership.

  bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));
  ASSERT_TRUE(ctx);
  X509 *cert = GetTestCertificate().release();
  ASSERT_TRUE(cert);
  SSL_CTX_add0_chain_cert(ctx.get(), cert);

  // This should not trigger a use-after-free.
  X509_cmp(cert, cert);
}

TEST(SSLTest, GetCertificate) {
  bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));
  ASSERT_TRUE(ctx);
  bssl::UniquePtr<X509> cert = GetTestCertificate();
  ASSERT_TRUE(cert);
  ASSERT_TRUE(SSL_CTX_use_certificate(ctx.get(), cert.get()));
  bssl::UniquePtr<SSL> ssl(SSL_new(ctx.get()));
  ASSERT_TRUE(ssl);

  X509 *cert2 = SSL_CTX_get0_certificate(ctx.get());
  ASSERT_TRUE(cert2);
  X509 *cert3 = SSL_get_certificate(ssl.get());
  ASSERT_TRUE(cert3);

  // The old and new certificates must be identical.
  EXPECT_EQ(0, X509_cmp(cert.get(), cert2));
  EXPECT_EQ(0, X509_cmp(cert.get(), cert3));

  uint8_t *der = nullptr;
  long der_len = i2d_X509(cert.get(), &der);
  ASSERT_LT(0, der_len);
  bssl::UniquePtr<uint8_t> free_der(der);

  uint8_t *der2 = nullptr;
  long der2_len = i2d_X509(cert2, &der2);
  ASSERT_LT(0, der2_len);
  bssl::UniquePtr<uint8_t> free_der2(der2);

  uint8_t *der3 = nullptr;
  long der3_len = i2d_X509(cert3, &der3);
  ASSERT_LT(0, der3_len);
  bssl::UniquePtr<uint8_t> free_der3(der3);

  // They must also encode identically.
  EXPECT_EQ(Bytes(der, der_len), Bytes(der2, der2_len));
  EXPECT_EQ(Bytes(der, der_len), Bytes(der3, der3_len));
}

TEST(SSLTest, SetChainAndKeyMismatch) {
  bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_with_buffers_method()));
  ASSERT_TRUE(ctx);

  bssl::UniquePtr<EVP_PKEY> key = GetTestKey();
  ASSERT_TRUE(key);
  bssl::UniquePtr<CRYPTO_BUFFER> leaf = GetChainTestCertificateBuffer();
  ASSERT_TRUE(leaf);
  std::vector<CRYPTO_BUFFER*> chain = {
      leaf.get(),
  };

  // Should fail because |GetTestKey| doesn't match the chain-test certificate.
  ASSERT_FALSE(SSL_CTX_set_chain_and_key(ctx.get(), &chain[0], chain.size(),
                                         key.get(), nullptr));
  ERR_clear_error();
}

TEST(SSLTest, SetChainAndKey) {
  bssl::UniquePtr<SSL_CTX> client_ctx(SSL_CTX_new(TLS_with_buffers_method()));
  ASSERT_TRUE(client_ctx);
  bssl::UniquePtr<SSL_CTX> server_ctx(SSL_CTX_new(TLS_with_buffers_method()));
  ASSERT_TRUE(server_ctx);

  ASSERT_EQ(nullptr, SSL_CTX_get0_chain(server_ctx.get()));

  bssl::UniquePtr<EVP_PKEY> key = GetChainTestKey();
  ASSERT_TRUE(key);
  bssl::UniquePtr<CRYPTO_BUFFER> leaf = GetChainTestCertificateBuffer();
  ASSERT_TRUE(leaf);
  bssl::UniquePtr<CRYPTO_BUFFER> intermediate =
      GetChainTestIntermediateBuffer();
  ASSERT_TRUE(intermediate);
  std::vector<CRYPTO_BUFFER*> chain = {
      leaf.get(), intermediate.get(),
  };
  ASSERT_TRUE(SSL_CTX_set_chain_and_key(server_ctx.get(), &chain[0],
                                        chain.size(), key.get(), nullptr));

  ASSERT_EQ(chain.size(),
            sk_CRYPTO_BUFFER_num(SSL_CTX_get0_chain(server_ctx.get())));

  SSL_CTX_set_custom_verify(
      client_ctx.get(), SSL_VERIFY_PEER,
      [](SSL *ssl, uint8_t *out_alert) -> ssl_verify_result_t {
        return ssl_verify_ok;
      });

  bssl::UniquePtr<SSL> client, server;
  ASSERT_TRUE(ConnectClientAndServer(&client, &server, client_ctx.get(),
                                     server_ctx.get()));
}

TEST(SSLTest, BuffersFailWithoutCustomVerify) {
  bssl::UniquePtr<SSL_CTX> client_ctx(SSL_CTX_new(TLS_with_buffers_method()));
  ASSERT_TRUE(client_ctx);
  bssl::UniquePtr<SSL_CTX> server_ctx(SSL_CTX_new(TLS_with_buffers_method()));
  ASSERT_TRUE(server_ctx);

  bssl::UniquePtr<EVP_PKEY> key = GetChainTestKey();
  ASSERT_TRUE(key);
  bssl::UniquePtr<CRYPTO_BUFFER> leaf = GetChainTestCertificateBuffer();
  ASSERT_TRUE(leaf);
  std::vector<CRYPTO_BUFFER*> chain = { leaf.get() };
  ASSERT_TRUE(SSL_CTX_set_chain_and_key(server_ctx.get(), &chain[0],
                                        chain.size(), key.get(), nullptr));

  // Without SSL_CTX_set_custom_verify(), i.e. with everything in the default
  // configuration, certificate verification should fail.
  bssl::UniquePtr<SSL> client, server;
  ASSERT_FALSE(ConnectClientAndServer(&client, &server, client_ctx.get(),
                                      server_ctx.get()));

  // Whereas with a verifier, the connection should succeed.
  SSL_CTX_set_custom_verify(
      client_ctx.get(), SSL_VERIFY_PEER,
      [](SSL *ssl, uint8_t *out_alert) -> ssl_verify_result_t {
        return ssl_verify_ok;
      });
  ASSERT_TRUE(ConnectClientAndServer(&client, &server, client_ctx.get(),
                                     server_ctx.get()));
}

TEST(SSLTest, CustomVerify) {
  bssl::UniquePtr<SSL_CTX> client_ctx(SSL_CTX_new(TLS_with_buffers_method()));
  ASSERT_TRUE(client_ctx);
  bssl::UniquePtr<SSL_CTX> server_ctx(SSL_CTX_new(TLS_with_buffers_method()));
  ASSERT_TRUE(server_ctx);

  bssl::UniquePtr<EVP_PKEY> key = GetChainTestKey();
  ASSERT_TRUE(key);
  bssl::UniquePtr<CRYPTO_BUFFER> leaf = GetChainTestCertificateBuffer();
  ASSERT_TRUE(leaf);
  std::vector<CRYPTO_BUFFER*> chain = { leaf.get() };
  ASSERT_TRUE(SSL_CTX_set_chain_and_key(server_ctx.get(), &chain[0],
                                        chain.size(), key.get(), nullptr));

  SSL_CTX_set_custom_verify(
      client_ctx.get(), SSL_VERIFY_PEER,
      [](SSL *ssl, uint8_t *out_alert) -> ssl_verify_result_t {
        return ssl_verify_ok;
      });

  bssl::UniquePtr<SSL> client, server;
  ASSERT_TRUE(ConnectClientAndServer(&client, &server, client_ctx.get(),
                                     server_ctx.get()));

  // With SSL_VERIFY_PEER, ssl_verify_invalid should result in a dropped
  // connection.
  SSL_CTX_set_custom_verify(
      client_ctx.get(), SSL_VERIFY_PEER,
      [](SSL *ssl, uint8_t *out_alert) -> ssl_verify_result_t {
        return ssl_verify_invalid;
      });

  ASSERT_FALSE(ConnectClientAndServer(&client, &server, client_ctx.get(),
                                      server_ctx.get()));

  // But with SSL_VERIFY_NONE, ssl_verify_invalid should not cause a dropped
  // connection.
  SSL_CTX_set_custom_verify(
      client_ctx.get(), SSL_VERIFY_NONE,
      [](SSL *ssl, uint8_t *out_alert) -> ssl_verify_result_t {
        return ssl_verify_invalid;
      });

  ASSERT_TRUE(ConnectClientAndServer(&client, &server, client_ctx.get(),
                                     server_ctx.get()));
}

TEST(SSLTest, ClientCABuffers) {
  bssl::UniquePtr<SSL_CTX> client_ctx(SSL_CTX_new(TLS_with_buffers_method()));
  ASSERT_TRUE(client_ctx);
  bssl::UniquePtr<SSL_CTX> server_ctx(SSL_CTX_new(TLS_with_buffers_method()));
  ASSERT_TRUE(server_ctx);

  bssl::UniquePtr<EVP_PKEY> key = GetChainTestKey();
  ASSERT_TRUE(key);
  bssl::UniquePtr<CRYPTO_BUFFER> leaf = GetChainTestCertificateBuffer();
  ASSERT_TRUE(leaf);
  bssl::UniquePtr<CRYPTO_BUFFER> intermediate =
      GetChainTestIntermediateBuffer();
  ASSERT_TRUE(intermediate);
  std::vector<CRYPTO_BUFFER *> chain = {
      leaf.get(),
      intermediate.get(),
  };
  ASSERT_TRUE(SSL_CTX_set_chain_and_key(server_ctx.get(), &chain[0],
                                        chain.size(), key.get(), nullptr));

  bssl::UniquePtr<CRYPTO_BUFFER> ca_name(
      CRYPTO_BUFFER_new(kTestName, sizeof(kTestName), nullptr));
  ASSERT_TRUE(ca_name);
  bssl::UniquePtr<STACK_OF(CRYPTO_BUFFER)> ca_names(
      sk_CRYPTO_BUFFER_new_null());
  ASSERT_TRUE(ca_names);
  ASSERT_TRUE(PushToStack(ca_names.get(), std::move(ca_name)));
  SSL_CTX_set0_client_CAs(server_ctx.get(), ca_names.release());

  // Configure client and server to accept all certificates.
  SSL_CTX_set_custom_verify(
      client_ctx.get(), SSL_VERIFY_PEER,
      [](SSL *ssl, uint8_t *out_alert) -> ssl_verify_result_t {
        return ssl_verify_ok;
      });
  SSL_CTX_set_custom_verify(
      server_ctx.get(), SSL_VERIFY_PEER,
      [](SSL *ssl, uint8_t *out_alert) -> ssl_verify_result_t {
        return ssl_verify_ok;
      });

  bool cert_cb_called = false;
  SSL_CTX_set_cert_cb(
      client_ctx.get(),
      [](SSL *ssl, void *arg) -> int {
        const STACK_OF(CRYPTO_BUFFER) *peer_names =
            SSL_get0_server_requested_CAs(ssl);
        EXPECT_EQ(1u, sk_CRYPTO_BUFFER_num(peer_names));
        CRYPTO_BUFFER *peer_name = sk_CRYPTO_BUFFER_value(peer_names, 0);
        EXPECT_EQ(Bytes(kTestName), Bytes(CRYPTO_BUFFER_data(peer_name),
                                          CRYPTO_BUFFER_len(peer_name)));
        *reinterpret_cast<bool *>(arg) = true;
        return 1;
      },
      &cert_cb_called);

  bssl::UniquePtr<SSL> client, server;
  ASSERT_TRUE(ConnectClientAndServer(&client, &server, client_ctx.get(),
                                     server_ctx.get()));
  EXPECT_TRUE(cert_cb_called);
}

// Configuring the empty cipher list, though an error, should still modify the
// configuration.
TEST(SSLTest, EmptyCipherList) {
  bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));
  ASSERT_TRUE(ctx);

  // Initially, the cipher list is not empty.
  EXPECT_NE(0u, sk_SSL_CIPHER_num(SSL_CTX_get_ciphers(ctx.get())));

  // Configuring the empty cipher list fails.
  EXPECT_FALSE(SSL_CTX_set_cipher_list(ctx.get(), ""));
  ERR_clear_error();

  // But the cipher list is still updated to empty.
  EXPECT_EQ(0u, sk_SSL_CIPHER_num(SSL_CTX_get_ciphers(ctx.get())));
}

// ssl_test_ticket_aead_failure_mode enumerates the possible ways in which the
// test |SSL_TICKET_AEAD_METHOD| can fail.
enum ssl_test_ticket_aead_failure_mode {
  ssl_test_ticket_aead_ok = 0,
  ssl_test_ticket_aead_seal_fail,
  ssl_test_ticket_aead_open_soft_fail,
  ssl_test_ticket_aead_open_hard_fail,
};

struct ssl_test_ticket_aead_state {
  unsigned retry_count;
  ssl_test_ticket_aead_failure_mode failure_mode;
};

static int ssl_test_ticket_aead_ex_index_dup(CRYPTO_EX_DATA *to,
                                             const CRYPTO_EX_DATA *from,
                                             void **from_d, int index,
                                             long argl, void *argp) {
  abort();
}

static void ssl_test_ticket_aead_ex_index_free(void *parent, void *ptr,
                                               CRYPTO_EX_DATA *ad, int index,
                                               long argl, void *argp) {
  auto state = reinterpret_cast<ssl_test_ticket_aead_state*>(ptr);
  if (state == nullptr) {
    return;
  }

  OPENSSL_free(state);
}

static CRYPTO_once_t g_ssl_test_ticket_aead_ex_index_once = CRYPTO_ONCE_INIT;
static int g_ssl_test_ticket_aead_ex_index;

static int ssl_test_ticket_aead_get_ex_index() {
  CRYPTO_once(&g_ssl_test_ticket_aead_ex_index_once, [] {
    g_ssl_test_ticket_aead_ex_index = SSL_get_ex_new_index(
        0, nullptr, nullptr, ssl_test_ticket_aead_ex_index_dup,
        ssl_test_ticket_aead_ex_index_free);
  });
  return g_ssl_test_ticket_aead_ex_index;
}

static size_t ssl_test_ticket_aead_max_overhead(SSL *ssl) {
  return 1;
}

static int ssl_test_ticket_aead_seal(SSL *ssl, uint8_t *out, size_t *out_len,
                                     size_t max_out_len, const uint8_t *in,
                                     size_t in_len) {
  auto state = reinterpret_cast<ssl_test_ticket_aead_state *>(
      SSL_get_ex_data(ssl, ssl_test_ticket_aead_get_ex_index()));

  if (state->failure_mode == ssl_test_ticket_aead_seal_fail ||
      max_out_len < in_len + 1) {
    return 0;
  }

  OPENSSL_memmove(out, in, in_len);
  out[in_len] = 0xff;
  *out_len = in_len + 1;

  return 1;
}

static ssl_ticket_aead_result_t ssl_test_ticket_aead_open(
    SSL *ssl, uint8_t *out, size_t *out_len, size_t max_out_len,
    const uint8_t *in, size_t in_len) {
  auto state = reinterpret_cast<ssl_test_ticket_aead_state *>(
      SSL_get_ex_data(ssl, ssl_test_ticket_aead_get_ex_index()));

  if (state->retry_count > 0) {
    state->retry_count--;
    return ssl_ticket_aead_retry;
  }

  switch (state->failure_mode) {
    case ssl_test_ticket_aead_ok:
      break;
    case ssl_test_ticket_aead_seal_fail:
      // If |seal| failed then there shouldn't be any ticket to try and
      // decrypt.
      abort();
      break;
    case ssl_test_ticket_aead_open_soft_fail:
      return ssl_ticket_aead_ignore_ticket;
    case ssl_test_ticket_aead_open_hard_fail:
      return ssl_ticket_aead_error;
  }

  if (in_len == 0 || in[in_len - 1] != 0xff) {
    return ssl_ticket_aead_ignore_ticket;
  }

  if (max_out_len < in_len - 1) {
    return ssl_ticket_aead_error;
  }

  OPENSSL_memmove(out, in, in_len - 1);
  *out_len = in_len - 1;
  return ssl_ticket_aead_success;
}

static const SSL_TICKET_AEAD_METHOD kSSLTestTicketMethod = {
  ssl_test_ticket_aead_max_overhead,
  ssl_test_ticket_aead_seal,
  ssl_test_ticket_aead_open,
};

static void ConnectClientAndServerWithTicketMethod(
    bssl::UniquePtr<SSL> *out_client, bssl::UniquePtr<SSL> *out_server,
    SSL_CTX *client_ctx, SSL_CTX *server_ctx, unsigned retry_count,
    ssl_test_ticket_aead_failure_mode failure_mode, SSL_SESSION *session) {
  bssl::UniquePtr<SSL> client(SSL_new(client_ctx)), server(SSL_new(server_ctx));
  ASSERT_TRUE(client);
  ASSERT_TRUE(server);
  SSL_set_connect_state(client.get());
  SSL_set_accept_state(server.get());

  auto state = reinterpret_cast<ssl_test_ticket_aead_state *>(
      OPENSSL_malloc(sizeof(ssl_test_ticket_aead_state)));
  ASSERT_TRUE(state);
  OPENSSL_memset(state, 0, sizeof(ssl_test_ticket_aead_state));
  state->retry_count = retry_count;
  state->failure_mode = failure_mode;

  ASSERT_TRUE(SSL_set_ex_data(server.get(), ssl_test_ticket_aead_get_ex_index(),
                              state));

  SSL_set_session(client.get(), session);

  BIO *bio1, *bio2;
  ASSERT_TRUE(BIO_new_bio_pair(&bio1, 0, &bio2, 0));

  // SSL_set_bio takes ownership.
  SSL_set_bio(client.get(), bio1, bio1);
  SSL_set_bio(server.get(), bio2, bio2);

  if (CompleteHandshakes(client.get(), server.get())) {
    *out_client = std::move(client);
    *out_server = std::move(server);
  } else {
    out_client->reset();
    out_server->reset();
  }
}

using TicketAEADMethodParam =
    testing::tuple<uint16_t, unsigned, ssl_test_ticket_aead_failure_mode>;

class TicketAEADMethodTest
    : public ::testing::TestWithParam<TicketAEADMethodParam> {};

TEST_P(TicketAEADMethodTest, Resume) {
  bssl::UniquePtr<X509> cert = GetTestCertificate();
  ASSERT_TRUE(cert);
  bssl::UniquePtr<EVP_PKEY> key = GetTestKey();
  ASSERT_TRUE(key);

  bssl::UniquePtr<SSL_CTX> server_ctx(SSL_CTX_new(TLS_method()));
  ASSERT_TRUE(server_ctx);
  bssl::UniquePtr<SSL_CTX> client_ctx(SSL_CTX_new(TLS_method()));
  ASSERT_TRUE(client_ctx);

  const uint16_t version = testing::get<0>(GetParam());
  const unsigned retry_count = testing::get<1>(GetParam());
  const ssl_test_ticket_aead_failure_mode failure_mode =
      testing::get<2>(GetParam());

  ASSERT_TRUE(SSL_CTX_use_certificate(server_ctx.get(), cert.get()));
  ASSERT_TRUE(SSL_CTX_use_PrivateKey(server_ctx.get(), key.get()));
  ASSERT_TRUE(SSL_CTX_set_min_proto_version(client_ctx.get(), version));
  ASSERT_TRUE(SSL_CTX_set_max_proto_version(client_ctx.get(), version));
  ASSERT_TRUE(SSL_CTX_set_min_proto_version(server_ctx.get(), version));
  ASSERT_TRUE(SSL_CTX_set_max_proto_version(server_ctx.get(), version));

  SSL_CTX_set_session_cache_mode(client_ctx.get(), SSL_SESS_CACHE_BOTH);
  SSL_CTX_set_session_cache_mode(server_ctx.get(), SSL_SESS_CACHE_BOTH);
  SSL_CTX_set_current_time_cb(client_ctx.get(), FrozenTimeCallback);
  SSL_CTX_set_current_time_cb(server_ctx.get(), FrozenTimeCallback);
  SSL_CTX_sess_set_new_cb(client_ctx.get(), SaveLastSession);

  SSL_CTX_set_ticket_aead_method(server_ctx.get(), &kSSLTestTicketMethod);

  bssl::UniquePtr<SSL> client, server;
  ConnectClientAndServerWithTicketMethod(&client, &server, client_ctx.get(),
                                         server_ctx.get(), retry_count,
                                         failure_mode, nullptr);
  switch (failure_mode) {
    case ssl_test_ticket_aead_ok:
    case ssl_test_ticket_aead_open_hard_fail:
    case ssl_test_ticket_aead_open_soft_fail:
      ASSERT_TRUE(client);
      break;
    case ssl_test_ticket_aead_seal_fail:
      EXPECT_FALSE(client);
      return;
  }
  EXPECT_FALSE(SSL_session_reused(client.get()));
  EXPECT_FALSE(SSL_session_reused(server.get()));

  ASSERT_TRUE(FlushNewSessionTickets(client.get(), server.get()));
  bssl::UniquePtr<SSL_SESSION> session = std::move(g_last_session);
  ConnectClientAndServerWithTicketMethod(&client, &server, client_ctx.get(),
                                         server_ctx.get(), retry_count,
                                         failure_mode, session.get());
  switch (failure_mode) {
    case ssl_test_ticket_aead_ok:
      ASSERT_TRUE(client);
      EXPECT_TRUE(SSL_session_reused(client.get()));
      EXPECT_TRUE(SSL_session_reused(server.get()));
      break;
    case ssl_test_ticket_aead_seal_fail:
      abort();
      break;
    case ssl_test_ticket_aead_open_hard_fail:
      EXPECT_FALSE(client);
      break;
    case ssl_test_ticket_aead_open_soft_fail:
      ASSERT_TRUE(client);
      EXPECT_FALSE(SSL_session_reused(client.get()));
      EXPECT_FALSE(SSL_session_reused(server.get()));
  }
}

std::string TicketAEADMethodParamToString(
    const testing::TestParamInfo<TicketAEADMethodParam> &params) {
  std::string ret = GetVersionName(std::get<0>(params.param));
  // GTest only allows alphanumeric characters and '_' in the parameter
  // string. Additionally filter out the 'v' to get "TLS13" over "TLSv13".
  for (auto it = ret.begin(); it != ret.end();) {
    if (*it == '.' || *it == 'v') {
      it = ret.erase(it);
    } else {
      ++it;
    }
  }
  char retry_count[256];
  snprintf(retry_count, sizeof(retry_count), "%d", std::get<1>(params.param));
  ret += "_";
  ret += retry_count;
  ret += "Retries_";
  switch (std::get<2>(params.param)) {
    case ssl_test_ticket_aead_ok:
      ret += "OK";
      break;
    case ssl_test_ticket_aead_seal_fail:
      ret += "SealFail";
      break;
    case ssl_test_ticket_aead_open_soft_fail:
      ret += "OpenSoftFail";
      break;
    case ssl_test_ticket_aead_open_hard_fail:
      ret += "OpenHardFail";
      break;
  }
  return ret;
}

INSTANTIATE_TEST_SUITE_P(
    TicketAEADMethodTests, TicketAEADMethodTest,
    testing::Combine(testing::Values(TLS1_2_VERSION, TLS1_3_VERSION),
                     testing::Values(0, 1, 2),
                     testing::Values(ssl_test_ticket_aead_ok,
                                     ssl_test_ticket_aead_seal_fail,
                                     ssl_test_ticket_aead_open_soft_fail,
                                     ssl_test_ticket_aead_open_hard_fail)),
    TicketAEADMethodParamToString);

TEST(SSLTest, SelectNextProto) {
  uint8_t *result;
  uint8_t result_len;

  // If there is an overlap, it should be returned.
  EXPECT_EQ(OPENSSL_NPN_NEGOTIATED,
            SSL_select_next_proto(&result, &result_len,
                                  (const uint8_t *)"\1a\2bb\3ccc", 9,
                                  (const uint8_t *)"\1x\1y\1a\1z", 8));
  EXPECT_EQ(Bytes("a"), Bytes(result, result_len));

  EXPECT_EQ(OPENSSL_NPN_NEGOTIATED,
            SSL_select_next_proto(&result, &result_len,
                                  (const uint8_t *)"\1a\2bb\3ccc", 9,
                                  (const uint8_t *)"\1x\1y\2bb\1z", 9));
  EXPECT_EQ(Bytes("bb"), Bytes(result, result_len));

  EXPECT_EQ(OPENSSL_NPN_NEGOTIATED,
            SSL_select_next_proto(&result, &result_len,
                                  (const uint8_t *)"\1a\2bb\3ccc", 9,
                                  (const uint8_t *)"\1x\1y\3ccc\1z", 10));
  EXPECT_EQ(Bytes("ccc"), Bytes(result, result_len));

  // Peer preference order takes precedence over local.
  EXPECT_EQ(OPENSSL_NPN_NEGOTIATED,
            SSL_select_next_proto(&result, &result_len,
                                  (const uint8_t *)"\1a\2bb\3ccc", 9,
                                  (const uint8_t *)"\3ccc\2bb\1a", 9));
  EXPECT_EQ(Bytes("a"), Bytes(result, result_len));

  // If there is no overlap, return the first local protocol.
  EXPECT_EQ(OPENSSL_NPN_NO_OVERLAP,
            SSL_select_next_proto(&result, &result_len,
                                  (const uint8_t *)"\1a\2bb\3ccc", 9,
                                  (const uint8_t *)"\1x\2yy\3zzz", 9));
  EXPECT_EQ(Bytes("x"), Bytes(result, result_len));

  EXPECT_EQ(OPENSSL_NPN_NO_OVERLAP,
            SSL_select_next_proto(&result, &result_len, nullptr, 0,
                                  (const uint8_t *)"\1x\2yy\3zzz", 9));
  EXPECT_EQ(Bytes("x"), Bytes(result, result_len));
}

TEST(SSLTest, SealRecord) {
  bssl::UniquePtr<SSL_CTX> client_ctx(SSL_CTX_new(TLSv1_2_method())),
      server_ctx(SSL_CTX_new(TLSv1_2_method()));
  ASSERT_TRUE(client_ctx);
  ASSERT_TRUE(server_ctx);

  bssl::UniquePtr<X509> cert = GetTestCertificate();
  bssl::UniquePtr<EVP_PKEY> key = GetTestKey();
  ASSERT_TRUE(cert);
  ASSERT_TRUE(key);
  ASSERT_TRUE(SSL_CTX_use_certificate(server_ctx.get(), cert.get()));
  ASSERT_TRUE(SSL_CTX_use_PrivateKey(server_ctx.get(), key.get()));

  bssl::UniquePtr<SSL> client, server;
  ASSERT_TRUE(ConnectClientAndServer(&client, &server, client_ctx.get(),
                                     server_ctx.get()));

  const std::vector<uint8_t> record = {1, 2, 3, 4, 5};
  std::vector<uint8_t> prefix(
      bssl::SealRecordPrefixLen(client.get(), record.size())),
      body(record.size()),
      suffix(bssl::SealRecordSuffixLen(client.get(), record.size()));
  ASSERT_TRUE(bssl::SealRecord(client.get(), bssl::MakeSpan(prefix),
                               bssl::MakeSpan(body), bssl::MakeSpan(suffix),
                               record));

  std::vector<uint8_t> sealed;
  sealed.insert(sealed.end(), prefix.begin(), prefix.end());
  sealed.insert(sealed.end(), body.begin(), body.end());
  sealed.insert(sealed.end(), suffix.begin(), suffix.end());
  std::vector<uint8_t> sealed_copy = sealed;

  bssl::Span<uint8_t> plaintext;
  size_t record_len;
  uint8_t alert = 255;
  EXPECT_EQ(bssl::OpenRecord(server.get(), &plaintext, &record_len, &alert,
                             bssl::MakeSpan(sealed)),
            bssl::OpenRecordResult::kOK);
  EXPECT_EQ(record_len, sealed.size());
  EXPECT_EQ(plaintext, record);
  EXPECT_EQ(255, alert);
}

TEST(SSLTest, SealRecordInPlace) {
  bssl::UniquePtr<SSL_CTX> client_ctx(SSL_CTX_new(TLSv1_2_method())),
      server_ctx(SSL_CTX_new(TLSv1_2_method()));
  ASSERT_TRUE(client_ctx);
  ASSERT_TRUE(server_ctx);

  bssl::UniquePtr<X509> cert = GetTestCertificate();
  bssl::UniquePtr<EVP_PKEY> key = GetTestKey();
  ASSERT_TRUE(cert);
  ASSERT_TRUE(key);
  ASSERT_TRUE(SSL_CTX_use_certificate(server_ctx.get(), cert.get()));
  ASSERT_TRUE(SSL_CTX_use_PrivateKey(server_ctx.get(), key.get()));

  bssl::UniquePtr<SSL> client, server;
  ASSERT_TRUE(ConnectClientAndServer(&client, &server, client_ctx.get(),
                                     server_ctx.get()));

  const std::vector<uint8_t> plaintext = {1, 2, 3, 4, 5};
  std::vector<uint8_t> record = plaintext;
  std::vector<uint8_t> prefix(
      bssl::SealRecordPrefixLen(client.get(), record.size())),
      suffix(bssl::SealRecordSuffixLen(client.get(), record.size()));
  ASSERT_TRUE(bssl::SealRecord(client.get(), bssl::MakeSpan(prefix),
                               bssl::MakeSpan(record), bssl::MakeSpan(suffix),
                               record));
  record.insert(record.begin(), prefix.begin(), prefix.end());
  record.insert(record.end(), suffix.begin(), suffix.end());

  bssl::Span<uint8_t> result;
  size_t record_len;
  uint8_t alert;
  EXPECT_EQ(bssl::OpenRecord(server.get(), &result, &record_len, &alert,
                             bssl::MakeSpan(record)),
            bssl::OpenRecordResult::kOK);
  EXPECT_EQ(record_len, record.size());
  EXPECT_EQ(plaintext, result);
}

TEST(SSLTest, SealRecordTrailingData) {
  bssl::UniquePtr<SSL_CTX> client_ctx(SSL_CTX_new(TLSv1_2_method())),
      server_ctx(SSL_CTX_new(TLSv1_2_method()));
  ASSERT_TRUE(client_ctx);
  ASSERT_TRUE(server_ctx);

  bssl::UniquePtr<X509> cert = GetTestCertificate();
  bssl::UniquePtr<EVP_PKEY> key = GetTestKey();
  ASSERT_TRUE(cert);
  ASSERT_TRUE(key);
  ASSERT_TRUE(SSL_CTX_use_certificate(server_ctx.get(), cert.get()));
  ASSERT_TRUE(SSL_CTX_use_PrivateKey(server_ctx.get(), key.get()));

  bssl::UniquePtr<SSL> client, server;
  ASSERT_TRUE(ConnectClientAndServer(&client, &server, client_ctx.get(),
                                     server_ctx.get()));

  const std::vector<uint8_t> plaintext = {1, 2, 3, 4, 5};
  std::vector<uint8_t> record = plaintext;
  std::vector<uint8_t> prefix(
      bssl::SealRecordPrefixLen(client.get(), record.size())),
      suffix(bssl::SealRecordSuffixLen(client.get(), record.size()));
  ASSERT_TRUE(bssl::SealRecord(client.get(), bssl::MakeSpan(prefix),
                               bssl::MakeSpan(record), bssl::MakeSpan(suffix),
                               record));
  record.insert(record.begin(), prefix.begin(), prefix.end());
  record.insert(record.end(), suffix.begin(), suffix.end());
  record.insert(record.end(), {5, 4, 3, 2, 1});

  bssl::Span<uint8_t> result;
  size_t record_len;
  uint8_t alert;
  EXPECT_EQ(bssl::OpenRecord(server.get(), &result, &record_len, &alert,
                             bssl::MakeSpan(record)),
            bssl::OpenRecordResult::kOK);
  EXPECT_EQ(record_len, record.size() - 5);
  EXPECT_EQ(plaintext, result);
}

TEST(SSLTest, SealRecordInvalidSpanSize) {
  bssl::UniquePtr<SSL_CTX> client_ctx(SSL_CTX_new(TLSv1_2_method())),
      server_ctx(SSL_CTX_new(TLSv1_2_method()));
  ASSERT_TRUE(client_ctx);
  ASSERT_TRUE(server_ctx);

  bssl::UniquePtr<X509> cert = GetTestCertificate();
  bssl::UniquePtr<EVP_PKEY> key = GetTestKey();
  ASSERT_TRUE(cert);
  ASSERT_TRUE(key);
  ASSERT_TRUE(SSL_CTX_use_certificate(server_ctx.get(), cert.get()));
  ASSERT_TRUE(SSL_CTX_use_PrivateKey(server_ctx.get(), key.get()));

  bssl::UniquePtr<SSL> client, server;
  ASSERT_TRUE(ConnectClientAndServer(&client, &server, client_ctx.get(),
                                     server_ctx.get()));

  std::vector<uint8_t> record = {1, 2, 3, 4, 5};
  std::vector<uint8_t> prefix(
      bssl::SealRecordPrefixLen(client.get(), record.size())),
      body(record.size()),
      suffix(bssl::SealRecordSuffixLen(client.get(), record.size()));

  auto expect_err = []() {
    int err = ERR_get_error();
    EXPECT_EQ(ERR_GET_LIB(err), ERR_LIB_SSL);
    EXPECT_EQ(ERR_GET_REASON(err), SSL_R_BUFFER_TOO_SMALL);
    ERR_clear_error();
  };
  EXPECT_FALSE(bssl::SealRecord(
      client.get(), bssl::MakeSpan(prefix.data(), prefix.size() - 1),
      bssl::MakeSpan(record), bssl::MakeSpan(suffix), record));
  expect_err();
  EXPECT_FALSE(bssl::SealRecord(
      client.get(), bssl::MakeSpan(prefix.data(), prefix.size() + 1),
      bssl::MakeSpan(record), bssl::MakeSpan(suffix), record));
  expect_err();

  EXPECT_FALSE(
      bssl::SealRecord(client.get(), bssl::MakeSpan(prefix),
                       bssl::MakeSpan(record.data(), record.size() - 1),
                       bssl::MakeSpan(suffix), record));
  expect_err();
  EXPECT_FALSE(
      bssl::SealRecord(client.get(), bssl::MakeSpan(prefix),
                       bssl::MakeSpan(record.data(), record.size() + 1),
                       bssl::MakeSpan(suffix), record));
  expect_err();

  EXPECT_FALSE(bssl::SealRecord(
      client.get(), bssl::MakeSpan(prefix), bssl::MakeSpan(record),
      bssl::MakeSpan(suffix.data(), suffix.size() - 1), record));
  expect_err();
  EXPECT_FALSE(bssl::SealRecord(
      client.get(), bssl::MakeSpan(prefix), bssl::MakeSpan(record),
      bssl::MakeSpan(suffix.data(), suffix.size() + 1), record));
  expect_err();
}

// The client should gracefully handle no suitable ciphers being enabled.
TEST(SSLTest, NoCiphersAvailable) {
  bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));
  ASSERT_TRUE(ctx);

  // Configure |client_ctx| with a cipher list that does not intersect with its
  // version configuration.
  ASSERT_TRUE(SSL_CTX_set_strict_cipher_list(
      ctx.get(), "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256"));
  ASSERT_TRUE(SSL_CTX_set_max_proto_version(ctx.get(), TLS1_1_VERSION));

  bssl::UniquePtr<SSL> ssl(SSL_new(ctx.get()));
  ASSERT_TRUE(ssl);
  SSL_set_connect_state(ssl.get());

  UniquePtr<BIO> rbio(BIO_new(BIO_s_mem())), wbio(BIO_new(BIO_s_mem()));
  ASSERT_TRUE(rbio);
  ASSERT_TRUE(wbio);
  SSL_set0_rbio(ssl.get(), rbio.release());
  SSL_set0_wbio(ssl.get(), wbio.release());

  int ret = SSL_do_handshake(ssl.get());
  EXPECT_EQ(-1, ret);
  EXPECT_EQ(SSL_ERROR_SSL, SSL_get_error(ssl.get(), ret));
  uint32_t err = ERR_get_error();
  EXPECT_EQ(ERR_LIB_SSL, ERR_GET_LIB(err));
  EXPECT_EQ(SSL_R_NO_CIPHERS_AVAILABLE, ERR_GET_REASON(err));
}

TEST_P(SSLVersionTest, SessionVersion) {
  SSL_CTX_set_session_cache_mode(client_ctx_.get(), SSL_SESS_CACHE_BOTH);
  SSL_CTX_set_session_cache_mode(server_ctx_.get(), SSL_SESS_CACHE_BOTH);

  bssl::UniquePtr<SSL_SESSION> session =
      CreateClientSession(client_ctx_.get(), server_ctx_.get());
  ASSERT_TRUE(session);
  EXPECT_EQ(version(), SSL_SESSION_get_protocol_version(session.get()));

  // Sessions in TLS 1.3 and later should be single-use.
  EXPECT_EQ(version() == TLS1_3_VERSION,
            !!SSL_SESSION_should_be_single_use(session.get()));

  // Making fake sessions for testing works.
  session.reset(SSL_SESSION_new(client_ctx_.get()));
  ASSERT_TRUE(session);
  ASSERT_TRUE(SSL_SESSION_set_protocol_version(session.get(), version()));
  EXPECT_EQ(version(), SSL_SESSION_get_protocol_version(session.get()));
}

TEST_P(SSLVersionTest, SSLPending) {
  UniquePtr<SSL> ssl(SSL_new(client_ctx_.get()));
  ASSERT_TRUE(ssl);
  EXPECT_EQ(0, SSL_pending(ssl.get()));

  ASSERT_TRUE(Connect());
  EXPECT_EQ(0, SSL_pending(client_.get()));

  ASSERT_EQ(5, SSL_write(server_.get(), "hello", 5));
  ASSERT_EQ(5, SSL_write(server_.get(), "world", 5));
  EXPECT_EQ(0, SSL_pending(client_.get()));

  char buf[10];
  ASSERT_EQ(1, SSL_peek(client_.get(), buf, 1));
  EXPECT_EQ(5, SSL_pending(client_.get()));

  ASSERT_EQ(1, SSL_read(client_.get(), buf, 1));
  EXPECT_EQ(4, SSL_pending(client_.get()));

  ASSERT_EQ(4, SSL_read(client_.get(), buf, 10));
  EXPECT_EQ(0, SSL_pending(client_.get()));

  ASSERT_EQ(2, SSL_read(client_.get(), buf, 2));
  EXPECT_EQ(3, SSL_pending(client_.get()));
}

// Test that post-handshake tickets consumed by |SSL_shutdown| are ignored.
TEST(SSLTest, ShutdownIgnoresTickets) {
  bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));
  ASSERT_TRUE(ctx);
  ASSERT_TRUE(SSL_CTX_set_min_proto_version(ctx.get(), TLS1_3_VERSION));
  ASSERT_TRUE(SSL_CTX_set_max_proto_version(ctx.get(), TLS1_3_VERSION));

  bssl::UniquePtr<X509> cert = GetTestCertificate();
  bssl::UniquePtr<EVP_PKEY> key = GetTestKey();
  ASSERT_TRUE(cert);
  ASSERT_TRUE(key);
  ASSERT_TRUE(SSL_CTX_use_certificate(ctx.get(), cert.get()));
  ASSERT_TRUE(SSL_CTX_use_PrivateKey(ctx.get(), key.get()));

  SSL_CTX_set_session_cache_mode(ctx.get(), SSL_SESS_CACHE_BOTH);

  bssl::UniquePtr<SSL> client, server;
  ASSERT_TRUE(ConnectClientAndServer(&client, &server, ctx.get(), ctx.get()));

  SSL_CTX_sess_set_new_cb(ctx.get(), [](SSL *ssl, SSL_SESSION *session) -> int {
    ADD_FAILURE() << "New session callback called during SSL_shutdown";
    return 0;
  });

  // Send close_notify.
  EXPECT_EQ(0, SSL_shutdown(server.get()));
  EXPECT_EQ(0, SSL_shutdown(client.get()));

  // Receive close_notify.
  EXPECT_EQ(1, SSL_shutdown(server.get()));
  EXPECT_EQ(1, SSL_shutdown(client.get()));
}

TEST(SSLTest, SignatureAlgorithmProperties) {
  EXPECT_EQ(EVP_PKEY_NONE, SSL_get_signature_algorithm_key_type(0x1234));
  EXPECT_EQ(nullptr, SSL_get_signature_algorithm_digest(0x1234));
  EXPECT_FALSE(SSL_is_signature_algorithm_rsa_pss(0x1234));

  EXPECT_EQ(EVP_PKEY_RSA,
            SSL_get_signature_algorithm_key_type(SSL_SIGN_RSA_PKCS1_MD5_SHA1));
  EXPECT_EQ(EVP_md5_sha1(),
            SSL_get_signature_algorithm_digest(SSL_SIGN_RSA_PKCS1_MD5_SHA1));
  EXPECT_FALSE(SSL_is_signature_algorithm_rsa_pss(SSL_SIGN_RSA_PKCS1_MD5_SHA1));

  EXPECT_EQ(EVP_PKEY_EC, SSL_get_signature_algorithm_key_type(
                             SSL_SIGN_ECDSA_SECP256R1_SHA256));
  EXPECT_EQ(EVP_sha256(), SSL_get_signature_algorithm_digest(
                              SSL_SIGN_ECDSA_SECP256R1_SHA256));
  EXPECT_FALSE(
      SSL_is_signature_algorithm_rsa_pss(SSL_SIGN_ECDSA_SECP256R1_SHA256));

  EXPECT_EQ(EVP_PKEY_RSA,
            SSL_get_signature_algorithm_key_type(SSL_SIGN_RSA_PSS_RSAE_SHA384));
  EXPECT_EQ(EVP_sha384(),
            SSL_get_signature_algorithm_digest(SSL_SIGN_RSA_PSS_RSAE_SHA384));
  EXPECT_TRUE(SSL_is_signature_algorithm_rsa_pss(SSL_SIGN_RSA_PSS_RSAE_SHA384));
}

static int XORCompressFunc(SSL *ssl, CBB *out, const uint8_t *in,
                           size_t in_len) {
  for (size_t i = 0; i < in_len; i++) {
    if (!CBB_add_u8(out, in[i] ^ 0x55)) {
      return 0;
    }
  }

  SSL_set_app_data(ssl, XORCompressFunc);

  return 1;
}

static int XORDecompressFunc(SSL *ssl, CRYPTO_BUFFER **out,
                             size_t uncompressed_len, const uint8_t *in,
                             size_t in_len) {
  if (in_len != uncompressed_len) {
    return 0;
  }

  uint8_t *data;
  *out = CRYPTO_BUFFER_alloc(&data, uncompressed_len);
  if (*out == nullptr) {
    return 0;
  }

  for (size_t i = 0; i < in_len; i++) {
    data[i] = in[i] ^ 0x55;
  }

  SSL_set_app_data(ssl, XORDecompressFunc);

  return 1;
}

TEST(SSLTest, CertCompression) {
  bssl::UniquePtr<SSL_CTX> client_ctx(SSL_CTX_new(TLS_method()));
  bssl::UniquePtr<SSL_CTX> server_ctx(SSL_CTX_new(TLS_method()));
  ASSERT_TRUE(client_ctx);
  ASSERT_TRUE(server_ctx);

  bssl::UniquePtr<X509> cert = GetTestCertificate();
  bssl::UniquePtr<EVP_PKEY> key = GetTestKey();
  ASSERT_TRUE(cert);
  ASSERT_TRUE(key);
  ASSERT_TRUE(SSL_CTX_use_certificate(server_ctx.get(), cert.get()));
  ASSERT_TRUE(SSL_CTX_use_PrivateKey(server_ctx.get(), key.get()));

  ASSERT_TRUE(SSL_CTX_set_max_proto_version(client_ctx.get(), TLS1_3_VERSION));
  ASSERT_TRUE(SSL_CTX_set_max_proto_version(server_ctx.get(), TLS1_3_VERSION));
  ASSERT_TRUE(SSL_CTX_add_cert_compression_alg(
      client_ctx.get(), 0x1234, XORCompressFunc, XORDecompressFunc));
  ASSERT_TRUE(SSL_CTX_add_cert_compression_alg(
      server_ctx.get(), 0x1234, XORCompressFunc, XORDecompressFunc));

  bssl::UniquePtr<SSL> client, server;
  ASSERT_TRUE(ConnectClientAndServer(&client, &server, client_ctx.get(),
                                     server_ctx.get()));

  EXPECT_TRUE(SSL_get_app_data(client.get()) == XORDecompressFunc);
  EXPECT_TRUE(SSL_get_app_data(server.get()) == XORCompressFunc);
}

void MoveBIOs(SSL *dest, SSL *src) {
  BIO *rbio = SSL_get_rbio(src);
  BIO_up_ref(rbio);
  SSL_set0_rbio(dest, rbio);

  BIO *wbio = SSL_get_wbio(src);
  BIO_up_ref(wbio);
  SSL_set0_wbio(dest, wbio);

  SSL_set0_rbio(src, nullptr);
  SSL_set0_wbio(src, nullptr);
}

TEST(SSLTest, Handoff) {
  bssl::UniquePtr<SSL_CTX> client_ctx(SSL_CTX_new(TLS_method()));
  bssl::UniquePtr<SSL_CTX> server_ctx(SSL_CTX_new(TLS_method()));
  bssl::UniquePtr<SSL_CTX> handshaker_ctx(SSL_CTX_new(TLS_method()));
  ASSERT_TRUE(client_ctx);
  ASSERT_TRUE(server_ctx);
  ASSERT_TRUE(handshaker_ctx);

  SSL_CTX_set_session_cache_mode(client_ctx.get(), SSL_SESS_CACHE_CLIENT);
  SSL_CTX_sess_set_new_cb(client_ctx.get(), SaveLastSession);
  SSL_CTX_set_handoff_mode(server_ctx.get(), 1);
  uint8_t keys[48];
  SSL_CTX_get_tlsext_ticket_keys(server_ctx.get(), &keys, sizeof(keys));
  SSL_CTX_set_tlsext_ticket_keys(handshaker_ctx.get(), &keys, sizeof(keys));

  bssl::UniquePtr<X509> cert = GetTestCertificate();
  bssl::UniquePtr<EVP_PKEY> key = GetTestKey();
  ASSERT_TRUE(cert);
  ASSERT_TRUE(key);
  ASSERT_TRUE(SSL_CTX_use_certificate(handshaker_ctx.get(), cert.get()));
  ASSERT_TRUE(SSL_CTX_use_PrivateKey(handshaker_ctx.get(), key.get()));

  for (bool early_data : {false, true}) {
    SCOPED_TRACE(early_data);
    for (bool is_resume : {false, true}) {
      SCOPED_TRACE(is_resume);
      bssl::UniquePtr<SSL> client, server;
      auto config = ClientConfig();
      config.early_data = early_data;
      if (is_resume) {
        ASSERT_TRUE(g_last_session);
        config.session = g_last_session.get();
      }
      if (is_resume && config.early_data) {
        EXPECT_GT(g_last_session->ticket_max_early_data, 0u);
      }
      ASSERT_TRUE(ConnectClientAndServer(&client, &server, client_ctx.get(),
                                         server_ctx.get(), config,
                                         false /* don't handshake */));

      int client_ret = SSL_do_handshake(client.get());
      int client_err = SSL_get_error(client.get(), client_ret);

      uint8_t byte_written;
      if (config.early_data && is_resume) {
        ASSERT_EQ(client_err, 0);
        EXPECT_TRUE(SSL_in_early_data(client.get()));
        // Attempt to write early data.
        byte_written = 43;
        EXPECT_EQ(SSL_write(client.get(), &byte_written, 1), 1);
      } else {
        ASSERT_EQ(client_err, SSL_ERROR_WANT_READ);
      }

      int server_ret = SSL_do_handshake(server.get());
      int server_err = SSL_get_error(server.get(), server_ret);
      ASSERT_EQ(server_err, SSL_ERROR_HANDOFF);

      ScopedCBB cbb;
      Array<uint8_t> handoff;
      SSL_CLIENT_HELLO hello;
      ASSERT_TRUE(CBB_init(cbb.get(), 256));
      ASSERT_TRUE(SSL_serialize_handoff(server.get(), cbb.get(), &hello));
      ASSERT_TRUE(CBBFinishArray(cbb.get(), &handoff));

      bssl::UniquePtr<SSL> handshaker(SSL_new(handshaker_ctx.get()));
      // Note split handshakes determines 0-RTT support, for both the current
      // handshake and newly-issued tickets, entirely by |handshaker|. There is
      // no need to call |SSL_set_early_data_enabled| on |server|.
      SSL_set_early_data_enabled(handshaker.get(), 1);
      ASSERT_TRUE(SSL_apply_handoff(handshaker.get(), handoff));

      MoveBIOs(handshaker.get(), server.get());

      int handshake_ret = SSL_do_handshake(handshaker.get());
      int handshake_err = SSL_get_error(handshaker.get(), handshake_ret);
      ASSERT_EQ(handshake_err, SSL_ERROR_HANDBACK);

      // Double-check that additional calls to |SSL_do_handshake| continue
      // to get |SSL_ERROR_HANDBACK|.
      handshake_ret = SSL_do_handshake(handshaker.get());
      handshake_err = SSL_get_error(handshaker.get(), handshake_ret);
      ASSERT_EQ(handshake_err, SSL_ERROR_HANDBACK);

      ScopedCBB cbb_handback;
      Array<uint8_t> handback;
      ASSERT_TRUE(CBB_init(cbb_handback.get(), 1024));
      ASSERT_TRUE(SSL_serialize_handback(handshaker.get(), cbb_handback.get()));
      ASSERT_TRUE(CBBFinishArray(cbb_handback.get(), &handback));

      bssl::UniquePtr<SSL> server2(SSL_new(server_ctx.get()));
      ASSERT_TRUE(SSL_apply_handback(server2.get(), handback));

      MoveBIOs(server2.get(), handshaker.get());
      ASSERT_TRUE(CompleteHandshakes(client.get(), server2.get()));
      EXPECT_EQ(is_resume, SSL_session_reused(client.get()));

      if (config.early_data && is_resume) {
        // In this case, one byte of early data has already been written above.
        EXPECT_TRUE(SSL_early_data_accepted(client.get()));
      } else {
        byte_written = 42;
        EXPECT_EQ(SSL_write(client.get(), &byte_written, 1), 1);
      }
      uint8_t byte;
      EXPECT_EQ(SSL_read(server2.get(), &byte, 1), 1);
      EXPECT_EQ(byte_written, byte);

      byte = 44;
      EXPECT_EQ(SSL_write(server2.get(), &byte, 1), 1);
      EXPECT_EQ(SSL_read(client.get(), &byte, 1), 1);
      EXPECT_EQ(44, byte);
    }
  }
}

TEST(SSLTest, HandoffDeclined) {
  bssl::UniquePtr<SSL_CTX> client_ctx(SSL_CTX_new(TLS_method()));
  bssl::UniquePtr<SSL_CTX> server_ctx(SSL_CTX_new(TLS_method()));
  ASSERT_TRUE(client_ctx);
  ASSERT_TRUE(server_ctx);

  SSL_CTX_set_handoff_mode(server_ctx.get(), 1);
  ASSERT_TRUE(SSL_CTX_set_max_proto_version(server_ctx.get(), TLS1_2_VERSION));

  bssl::UniquePtr<X509> cert = GetTestCertificate();
  bssl::UniquePtr<EVP_PKEY> key = GetTestKey();
  ASSERT_TRUE(cert);
  ASSERT_TRUE(key);
  ASSERT_TRUE(SSL_CTX_use_certificate(server_ctx.get(), cert.get()));
  ASSERT_TRUE(SSL_CTX_use_PrivateKey(server_ctx.get(), key.get()));

  bssl::UniquePtr<SSL> client, server;
  ASSERT_TRUE(ConnectClientAndServer(&client, &server, client_ctx.get(),
                                     server_ctx.get(), ClientConfig(),
                                     false /* don't handshake */));

  int client_ret = SSL_do_handshake(client.get());
  int client_err = SSL_get_error(client.get(), client_ret);
  ASSERT_EQ(client_err, SSL_ERROR_WANT_READ);

  int server_ret = SSL_do_handshake(server.get());
  int server_err = SSL_get_error(server.get(), server_ret);
  ASSERT_EQ(server_err, SSL_ERROR_HANDOFF);

  ScopedCBB cbb;
  SSL_CLIENT_HELLO hello;
  ASSERT_TRUE(CBB_init(cbb.get(), 256));
  ASSERT_TRUE(SSL_serialize_handoff(server.get(), cbb.get(), &hello));

  ASSERT_TRUE(SSL_decline_handoff(server.get()));

  ASSERT_TRUE(CompleteHandshakes(client.get(), server.get()));

  uint8_t byte = 42;
  EXPECT_EQ(SSL_write(client.get(), &byte, 1), 1);
  EXPECT_EQ(SSL_read(server.get(), &byte, 1), 1);
  EXPECT_EQ(42, byte);

  byte = 43;
  EXPECT_EQ(SSL_write(server.get(), &byte, 1), 1);
  EXPECT_EQ(SSL_read(client.get(), &byte, 1), 1);
  EXPECT_EQ(43, byte);
}

static std::string SigAlgsToString(Span<const uint16_t> sigalgs) {
  std::string ret = "{";

  for (uint16_t v : sigalgs) {
    if (ret.size() > 1) {
      ret += ", ";
    }

    char buf[8];
    snprintf(buf, sizeof(buf) - 1, "0x%02x", v);
    buf[sizeof(buf)-1] = 0;
    ret += std::string(buf);
  }

  ret += "}";
  return ret;
}

void ExpectSigAlgsEqual(Span<const uint16_t> expected,
                        Span<const uint16_t> actual) {
  bool matches = false;
  if (expected.size() == actual.size()) {
    matches = true;

    for (size_t i = 0; i < expected.size(); i++) {
      if (expected[i] != actual[i]) {
        matches = false;
        break;
      }
    }
  }

  if (!matches) {
    ADD_FAILURE() << "expected: " << SigAlgsToString(expected)
                  << " got: " << SigAlgsToString(actual);
  }
}

TEST(SSLTest, SigAlgs) {
  static const struct {
    std::vector<int> input;
    bool ok;
    std::vector<uint16_t> expected;
  } kTests[] = {
      {{}, true, {}},
      {{1}, false, {}},
      {{1, 2, 3}, false, {}},
      {{NID_sha256, EVP_PKEY_ED25519}, false, {}},
      {{NID_sha256, EVP_PKEY_RSA, NID_sha256, EVP_PKEY_RSA}, false, {}},

      {{NID_sha256, EVP_PKEY_RSA}, true, {SSL_SIGN_RSA_PKCS1_SHA256}},
      {{NID_sha512, EVP_PKEY_RSA}, true, {SSL_SIGN_RSA_PKCS1_SHA512}},
      {{NID_sha256, EVP_PKEY_RSA_PSS}, true, {SSL_SIGN_RSA_PSS_RSAE_SHA256}},
      {{NID_undef, EVP_PKEY_ED25519}, true, {SSL_SIGN_ED25519}},
      {{NID_undef, EVP_PKEY_ED25519, NID_sha384, EVP_PKEY_EC},
       true,
       {SSL_SIGN_ED25519, SSL_SIGN_ECDSA_SECP384R1_SHA384}},
  };

  UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));

  unsigned n = 1;
  for (const auto &test : kTests) {
    SCOPED_TRACE(n++);

    const bool ok =
        SSL_CTX_set1_sigalgs(ctx.get(), test.input.data(), test.input.size());
    EXPECT_EQ(ok, test.ok);

    if (!ok) {
      ERR_clear_error();
    }

    if (!test.ok) {
      continue;
    }

    ExpectSigAlgsEqual(test.expected, ctx->cert->sigalgs);
  }
}

TEST(SSLTest, SigAlgsList) {
  static const struct {
    const char *input;
    bool ok;
    std::vector<uint16_t> expected;
  } kTests[] = {
      {"", false, {}},
      {":", false, {}},
      {"+", false, {}},
      {"RSA", false, {}},
      {"RSA+", false, {}},
      {"RSA+SHA256:", false, {}},
      {":RSA+SHA256:", false, {}},
      {":RSA+SHA256+:", false, {}},
      {"!", false, {}},
      {"\x01", false, {}},
      {"RSA+SHA256:RSA+SHA384:RSA+SHA256", false, {}},
      {"RSA-PSS+SHA256:rsa_pss_rsae_sha256", false, {}},

      {"RSA+SHA256", true, {SSL_SIGN_RSA_PKCS1_SHA256}},
      {"RSA+SHA256:ed25519",
       true,
       {SSL_SIGN_RSA_PKCS1_SHA256, SSL_SIGN_ED25519}},
      {"ECDSA+SHA256:RSA+SHA512",
       true,
       {SSL_SIGN_ECDSA_SECP256R1_SHA256, SSL_SIGN_RSA_PKCS1_SHA512}},
      {"ecdsa_secp256r1_sha256:rsa_pss_rsae_sha256",
       true,
       {SSL_SIGN_ECDSA_SECP256R1_SHA256, SSL_SIGN_RSA_PSS_RSAE_SHA256}},
      {"RSA-PSS+SHA256", true, {SSL_SIGN_RSA_PSS_RSAE_SHA256}},
      {"PSS+SHA256", true, {SSL_SIGN_RSA_PSS_RSAE_SHA256}},
  };

  UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));

  unsigned n = 1;
  for (const auto &test : kTests) {
    SCOPED_TRACE(n++);

    const bool ok = SSL_CTX_set1_sigalgs_list(ctx.get(), test.input);
    EXPECT_EQ(ok, test.ok);

    if (!ok) {
      if (test.ok) {
        ERR_print_errors_fp(stderr);
      }
      ERR_clear_error();
    }

    if (!test.ok) {
      continue;
    }

    ExpectSigAlgsEqual(test.expected, ctx->cert->sigalgs);
  }
}

TEST(SSLTest, ApplyHandoffRemovesUnsupportedCiphers) {
  bssl::UniquePtr<SSL_CTX> server_ctx(SSL_CTX_new(TLS_method()));
  bssl::UniquePtr<SSL> server(SSL_new(server_ctx.get()));

  // handoff is a handoff message that has been artificially modified to pretend
  // that only cipher 0x0A is supported.  When it is applied to |server|, all
  // ciphers but that one should be removed.
  //
  // To make a new one of these, try sticking this in the |Handoff| test above:
  //
  // hexdump(stderr, "", handoff.data(), handoff.size());
  // sed -e 's/\(..\)/0x\1, /g'
  //
  // and modify serialize_features() to emit only cipher 0x0A.

  uint8_t handoff[] = {
      0x30, 0x81, 0x9a, 0x02, 0x01, 0x00, 0x04, 0x00, 0x04, 0x81, 0x82, 0x01,
      0x00, 0x00, 0x7e, 0x03, 0x03, 0x30, 0x8e, 0x8f, 0x79, 0xd2, 0x87, 0x39,
      0xc2, 0x23, 0x23, 0x13, 0xca, 0x3c, 0x80, 0x44, 0xfd, 0x80, 0x83, 0x62,
      0x3c, 0xcc, 0xf8, 0x76, 0xd3, 0x62, 0xbb, 0x54, 0xe3, 0xc4, 0x39, 0x24,
      0xa5, 0x00, 0x00, 0x1e, 0xc0, 0x2b, 0xc0, 0x2f, 0xc0, 0x2c, 0xc0, 0x30,
      0xcc, 0xa9, 0xcc, 0xa8, 0xc0, 0x09, 0xc0, 0x13, 0xc0, 0x0a, 0xc0, 0x14,
      0x00, 0x9c, 0x00, 0x9d, 0x00, 0x2f, 0x00, 0x35, 0x00, 0x0a, 0x01, 0x00,
      0x00, 0x37, 0x00, 0x17, 0x00, 0x00, 0xff, 0x01, 0x00, 0x01, 0x00, 0x00,
      0x0a, 0x00, 0x08, 0x00, 0x06, 0x00, 0x1d, 0x00, 0x17, 0x00, 0x18, 0x00,
      0x0b, 0x00, 0x02, 0x01, 0x00, 0x00, 0x23, 0x00, 0x00, 0x00, 0x0d, 0x00,
      0x14, 0x00, 0x12, 0x04, 0x03, 0x08, 0x04, 0x04, 0x01, 0x05, 0x03, 0x08,
      0x05, 0x05, 0x01, 0x08, 0x06, 0x06, 0x01, 0x02, 0x01, 0x04, 0x02, 0x00,
      0x0a, 0x04, 0x0a, 0x00, 0x15, 0x00, 0x17, 0x00, 0x18, 0x00, 0x19, 0x00,
      0x1d,
  };

  EXPECT_EQ(20u, sk_SSL_CIPHER_num(SSL_get_ciphers(server.get())));
  ASSERT_TRUE(
      SSL_apply_handoff(server.get(), {handoff, OPENSSL_ARRAY_SIZE(handoff)}));
  EXPECT_EQ(1u, sk_SSL_CIPHER_num(SSL_get_ciphers(server.get())));
}

TEST(SSLTest, ApplyHandoffRemovesUnsupportedCurves) {
  bssl::UniquePtr<SSL_CTX> server_ctx(SSL_CTX_new(TLS_method()));
  bssl::UniquePtr<SSL> server(SSL_new(server_ctx.get()));

  // handoff is a handoff message that has been artificially modified to pretend
  // that only one curve is supported.  When it is applied to |server|, all
  // curves but that one should be removed.
  //
  // See |ApplyHandoffRemovesUnsupportedCiphers| for how to make a new one of
  // these.
  uint8_t handoff[] = {
      0x30, 0x81, 0xc0, 0x02, 0x01, 0x00, 0x04, 0x00, 0x04, 0x81, 0x82, 0x01,
      0x00, 0x00, 0x7e, 0x03, 0x03, 0x98, 0x30, 0xce, 0xd9, 0xb0, 0xdf, 0x5f,
      0x82, 0x05, 0x4a, 0x43, 0x67, 0x7e, 0xdb, 0x6a, 0x4f, 0x21, 0x18, 0x4e,
      0x0d, 0x94, 0x63, 0x18, 0x8b, 0x54, 0x89, 0xdb, 0x8b, 0x1d, 0x84, 0xbc,
      0x09, 0x00, 0x00, 0x1e, 0xc0, 0x2b, 0xc0, 0x2f, 0xc0, 0x2c, 0xc0, 0x30,
      0xcc, 0xa9, 0xcc, 0xa8, 0xc0, 0x09, 0xc0, 0x13, 0xc0, 0x0a, 0xc0, 0x14,
      0x00, 0x9c, 0x00, 0x9d, 0x00, 0x2f, 0x00, 0x35, 0x00, 0x0a, 0x01, 0x00,
      0x00, 0x37, 0x00, 0x17, 0x00, 0x00, 0xff, 0x01, 0x00, 0x01, 0x00, 0x00,
      0x0a, 0x00, 0x08, 0x00, 0x06, 0x00, 0x1d, 0x00, 0x17, 0x00, 0x18, 0x00,
      0x0b, 0x00, 0x02, 0x01, 0x00, 0x00, 0x23, 0x00, 0x00, 0x00, 0x0d, 0x00,
      0x14, 0x00, 0x12, 0x04, 0x03, 0x08, 0x04, 0x04, 0x01, 0x05, 0x03, 0x08,
      0x05, 0x05, 0x01, 0x08, 0x06, 0x06, 0x01, 0x02, 0x01, 0x04, 0x30, 0x00,
      0x02, 0x00, 0x0a, 0x00, 0x2f, 0x00, 0x35, 0x00, 0x8c, 0x00, 0x8d, 0x00,
      0x9c, 0x00, 0x9d, 0x13, 0x01, 0x13, 0x02, 0x13, 0x03, 0xc0, 0x09, 0xc0,
      0x0a, 0xc0, 0x13, 0xc0, 0x14, 0xc0, 0x2b, 0xc0, 0x2c, 0xc0, 0x2f, 0xc0,
      0x30, 0xc0, 0x35, 0xc0, 0x36, 0xcc, 0xa8, 0xcc, 0xa9, 0xcc, 0xac, 0x04,
      0x02, 0x00, 0x17,
  };

  // The zero length means that the default list of groups is used.
  EXPECT_EQ(0u, server->config->supported_group_list.size());
  ASSERT_TRUE(
      SSL_apply_handoff(server.get(), {handoff, OPENSSL_ARRAY_SIZE(handoff)}));
  EXPECT_EQ(1u, server->config->supported_group_list.size());
}

TEST(SSLTest, ZeroSizedWiteFlushesHandshakeMessages) {
  // If there are pending handshake mesages, an |SSL_write| of zero bytes should
  // flush them.
  bssl::UniquePtr<SSL_CTX> server_ctx(SSL_CTX_new(TLS_method()));
  EXPECT_TRUE(SSL_CTX_set_max_proto_version(server_ctx.get(), TLS1_3_VERSION));
  EXPECT_TRUE(SSL_CTX_set_min_proto_version(server_ctx.get(), TLS1_3_VERSION));
  bssl::UniquePtr<X509> cert = GetTestCertificate();
  bssl::UniquePtr<EVP_PKEY> key = GetTestKey();
  ASSERT_TRUE(cert);
  ASSERT_TRUE(key);
  ASSERT_TRUE(SSL_CTX_use_certificate(server_ctx.get(), cert.get()));
  ASSERT_TRUE(SSL_CTX_use_PrivateKey(server_ctx.get(), key.get()));

  bssl::UniquePtr<SSL_CTX> client_ctx(SSL_CTX_new(TLS_method()));
  EXPECT_TRUE(SSL_CTX_set_max_proto_version(client_ctx.get(), TLS1_3_VERSION));
  EXPECT_TRUE(SSL_CTX_set_min_proto_version(client_ctx.get(), TLS1_3_VERSION));

  bssl::UniquePtr<SSL> client, server;
  ASSERT_TRUE(ConnectClientAndServer(&client, &server, client_ctx.get(),
                                     server_ctx.get()));

  BIO *client_wbio = SSL_get_wbio(client.get());
  EXPECT_EQ(0u, BIO_wpending(client_wbio));
  EXPECT_TRUE(SSL_key_update(client.get(), SSL_KEY_UPDATE_NOT_REQUESTED));
  EXPECT_EQ(0u, BIO_wpending(client_wbio));
  EXPECT_EQ(0, SSL_write(client.get(), nullptr, 0));
  EXPECT_NE(0u, BIO_wpending(client_wbio));
}

TEST_P(SSLVersionTest, VerifyBeforeCertRequest) {
  // Configure the server to request client certificates.
  SSL_CTX_set_custom_verify(
      server_ctx_.get(), SSL_VERIFY_PEER,
      [](SSL *ssl, uint8_t *out_alert) { return ssl_verify_ok; });

  // Configure the client to reject the server certificate.
  SSL_CTX_set_custom_verify(
      client_ctx_.get(), SSL_VERIFY_PEER,
      [](SSL *ssl, uint8_t *out_alert) { return ssl_verify_invalid; });

  // cert_cb should not be called. Verification should fail first.
  SSL_CTX_set_cert_cb(client_ctx_.get(),
                      [](SSL *ssl, void *arg) {
                        ADD_FAILURE() << "cert_cb unexpectedly called";
                        return 0;
                      },
                      nullptr);

  bssl::UniquePtr<SSL> client, server;
  EXPECT_FALSE(ConnectClientAndServer(&client, &server, client_ctx_.get(),
                                      server_ctx_.get()));
}

// Test that ticket-based sessions on the client get fake session IDs.
TEST_P(SSLVersionTest, FakeIDsForTickets) {
  SSL_CTX_set_session_cache_mode(client_ctx_.get(), SSL_SESS_CACHE_BOTH);
  SSL_CTX_set_session_cache_mode(server_ctx_.get(), SSL_SESS_CACHE_BOTH);

  bssl::UniquePtr<SSL_SESSION> session =
      CreateClientSession(client_ctx_.get(), server_ctx_.get());
  ASSERT_TRUE(session);

  EXPECT_TRUE(SSL_SESSION_has_ticket(session.get()));
  unsigned session_id_length;
  SSL_SESSION_get_id(session.get(), &session_id_length);
  EXPECT_NE(session_id_length, 0u);
}

// These tests test multi-threaded behavior. They are intended to run with
// ThreadSanitizer.
#if defined(OPENSSL_THREADS)
TEST_P(SSLVersionTest, SessionCacheThreads) {
  SSL_CTX_set_options(server_ctx_.get(), SSL_OP_NO_TICKET);
  SSL_CTX_set_session_cache_mode(client_ctx_.get(), SSL_SESS_CACHE_BOTH);
  SSL_CTX_set_session_cache_mode(server_ctx_.get(), SSL_SESS_CACHE_BOTH);

  if (version() == TLS1_3_VERSION) {
    // Our TLS 1.3 implementation does not support stateful resumption.
    ASSERT_FALSE(CreateClientSession(client_ctx_.get(), server_ctx_.get()));
    return;
  }

  // Establish two client sessions to test with.
  bssl::UniquePtr<SSL_SESSION> session1 =
      CreateClientSession(client_ctx_.get(), server_ctx_.get());
  ASSERT_TRUE(session1);
  bssl::UniquePtr<SSL_SESSION> session2 =
      CreateClientSession(client_ctx_.get(), server_ctx_.get());
  ASSERT_TRUE(session2);

  auto connect_with_session = [&](SSL_SESSION *session) {
    ClientConfig config;
    config.session = session;
    UniquePtr<SSL> client, server;
    EXPECT_TRUE(ConnectClientAndServer(&client, &server, client_ctx_.get(),
                                       server_ctx_.get(), config));
  };

  // Resume sessions in parallel with establishing new ones.
  {
    std::vector<std::thread> threads;
    threads.emplace_back([&] { connect_with_session(nullptr); });
    threads.emplace_back([&] { connect_with_session(nullptr); });
    threads.emplace_back([&] { connect_with_session(session1.get()); });
    threads.emplace_back([&] { connect_with_session(session1.get()); });
    threads.emplace_back([&] { connect_with_session(session2.get()); });
    threads.emplace_back([&] { connect_with_session(session2.get()); });
    for (auto &thread : threads) {
      thread.join();
    }
  }

  // Hit the maximum session cache size across multiple threads
  size_t limit = SSL_CTX_sess_number(server_ctx_.get()) + 2;
  SSL_CTX_sess_set_cache_size(server_ctx_.get(), limit);
  {
    std::vector<std::thread> threads;
    for (int i = 0; i < 4; i++) {
      threads.emplace_back([&]() {
        connect_with_session(nullptr);
        EXPECT_LE(SSL_CTX_sess_number(server_ctx_.get()), limit);
      });
    }
    for (auto &thread : threads) {
      thread.join();
    }
    EXPECT_EQ(SSL_CTX_sess_number(server_ctx_.get()), limit);
  }
}

TEST_P(SSLVersionTest, SessionTicketThreads) {
  for (bool renew_ticket : {false, true}) {
    SCOPED_TRACE(renew_ticket);
    ResetContexts();
    SSL_CTX_set_session_cache_mode(client_ctx_.get(), SSL_SESS_CACHE_BOTH);
    SSL_CTX_set_session_cache_mode(server_ctx_.get(), SSL_SESS_CACHE_BOTH);
    if (renew_ticket) {
      SSL_CTX_set_tlsext_ticket_key_cb(server_ctx_.get(), RenewTicketCallback);
    }

    // Establish two client sessions to test with.
    bssl::UniquePtr<SSL_SESSION> session1 =
        CreateClientSession(client_ctx_.get(), server_ctx_.get());
    ASSERT_TRUE(session1);
    bssl::UniquePtr<SSL_SESSION> session2 =
        CreateClientSession(client_ctx_.get(), server_ctx_.get());
    ASSERT_TRUE(session2);

    auto connect_with_session = [&](SSL_SESSION *session) {
      ClientConfig config;
      config.session = session;
      UniquePtr<SSL> client, server;
      EXPECT_TRUE(ConnectClientAndServer(&client, &server, client_ctx_.get(),
                                         server_ctx_.get(), config));
    };

    // Resume sessions in parallel with establishing new ones.
    {
      std::vector<std::thread> threads;
      threads.emplace_back([&] { connect_with_session(nullptr); });
      threads.emplace_back([&] { connect_with_session(nullptr); });
      threads.emplace_back([&] { connect_with_session(session1.get()); });
      threads.emplace_back([&] { connect_with_session(session1.get()); });
      threads.emplace_back([&] { connect_with_session(session2.get()); });
      threads.emplace_back([&] { connect_with_session(session2.get()); });
      for (auto &thread : threads) {
        thread.join();
      }
    }
  }
}

// SSL_CTX_get0_certificate needs to lock internally. Test this works.
TEST(SSLTest, GetCertificateThreads) {
  bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));
  ASSERT_TRUE(ctx);
  bssl::UniquePtr<X509> cert = GetTestCertificate();
  ASSERT_TRUE(cert);
  ASSERT_TRUE(SSL_CTX_use_certificate(ctx.get(), cert.get()));

  // Existing code expects |SSL_CTX_get0_certificate| to be callable from two
  // threads concurrently. It originally was an immutable operation. Now we
  // implement it with a thread-safe cache, so it is worth testing.
  X509 *cert2_thread;
  std::thread thread(
      [&] { cert2_thread = SSL_CTX_get0_certificate(ctx.get()); });
  X509 *cert2 = SSL_CTX_get0_certificate(ctx.get());
  thread.join();

  EXPECT_EQ(cert2, cert2_thread);
  EXPECT_EQ(0, X509_cmp(cert.get(), cert2));
}

// Functions which access properties on the negotiated session are thread-safe
// where needed. Prior to TLS 1.3, clients resuming sessions and servers
// performing stateful resumption will share an underlying SSL_SESSION object,
// potentially across threads.
TEST_P(SSLVersionTest, SessionPropertiesThreads) {
  if (version() == TLS1_3_VERSION) {
    // Our TLS 1.3 implementation does not support stateful resumption.
    ASSERT_FALSE(CreateClientSession(client_ctx_.get(), server_ctx_.get()));
    return;
  }

  SSL_CTX_set_options(server_ctx_.get(), SSL_OP_NO_TICKET);
  SSL_CTX_set_session_cache_mode(client_ctx_.get(), SSL_SESS_CACHE_BOTH);
  SSL_CTX_set_session_cache_mode(server_ctx_.get(), SSL_SESS_CACHE_BOTH);

  ASSERT_TRUE(UseCertAndKey(client_ctx_.get()));
  ASSERT_TRUE(UseCertAndKey(server_ctx_.get()));

  // Configure mutual authentication, so we have more session state.
  SSL_CTX_set_custom_verify(
      client_ctx_.get(), SSL_VERIFY_PEER,
      [](SSL *ssl, uint8_t *out_alert) { return ssl_verify_ok; });
  SSL_CTX_set_custom_verify(
      server_ctx_.get(), SSL_VERIFY_PEER,
      [](SSL *ssl, uint8_t *out_alert) { return ssl_verify_ok; });

  // Establish a client session to test with.
  bssl::UniquePtr<SSL_SESSION> session =
      CreateClientSession(client_ctx_.get(), server_ctx_.get());
  ASSERT_TRUE(session);

  // Resume with it twice.
  UniquePtr<SSL> ssls[4];
  ClientConfig config;
  config.session = session.get();
  ASSERT_TRUE(ConnectClientAndServer(&ssls[0], &ssls[1], client_ctx_.get(),
                                     server_ctx_.get(), config));
  ASSERT_TRUE(ConnectClientAndServer(&ssls[2], &ssls[3], client_ctx_.get(),
                                     server_ctx_.get(), config));

  // Read properties in parallel.
  auto read_properties = [](const SSL *ssl) {
    EXPECT_TRUE(SSL_get_peer_cert_chain(ssl));
    bssl::UniquePtr<X509> peer(SSL_get_peer_certificate(ssl));
    EXPECT_TRUE(peer);
    EXPECT_TRUE(SSL_get_current_cipher(ssl));
    EXPECT_TRUE(SSL_get_curve_id(ssl));
  };

  std::vector<std::thread> threads;
  for (const auto &ssl_ptr : ssls) {
    const SSL *ssl = ssl_ptr.get();
    threads.emplace_back([=] { read_properties(ssl); });
  }
  for (auto &thread : threads) {
    thread.join();
  }
}
#endif  // OPENSSL_THREADS

constexpr size_t kNumQUICLevels = 4;
static_assert(ssl_encryption_initial < kNumQUICLevels,
              "kNumQUICLevels is wrong");
static_assert(ssl_encryption_early_data < kNumQUICLevels,
              "kNumQUICLevels is wrong");
static_assert(ssl_encryption_handshake < kNumQUICLevels,
              "kNumQUICLevels is wrong");
static_assert(ssl_encryption_application < kNumQUICLevels,
              "kNumQUICLevels is wrong");

const char *LevelToString(ssl_encryption_level_t level) {
  switch (level) {
    case ssl_encryption_initial:
      return "initial";
    case ssl_encryption_early_data:
      return "early data";
    case ssl_encryption_handshake:
      return "handshake";
    case ssl_encryption_application:
      return "application";
  }
  return "<unknown>";
}

class MockQUICTransport {
 public:
  enum class Role { kClient, kServer };

  explicit MockQUICTransport(Role role) : role_(role) {
    // The caller is expected to configure initial secrets.
    levels_[ssl_encryption_initial].write_secret = {1};
    levels_[ssl_encryption_initial].read_secret = {1};
  }

  void set_peer(MockQUICTransport *peer) { peer_ = peer; }

  bool has_alert() const { return has_alert_; }
  ssl_encryption_level_t alert_level() const { return alert_level_; }
  uint8_t alert() const { return alert_; }

  bool PeerSecretsMatch(ssl_encryption_level_t level) const {
    return levels_[level].write_secret == peer_->levels_[level].read_secret &&
           levels_[level].read_secret == peer_->levels_[level].write_secret &&
           levels_[level].cipher == peer_->levels_[level].cipher;
  }

  bool HasReadSecret(ssl_encryption_level_t level) const {
    return !levels_[level].read_secret.empty();
  }

  bool HasWriteSecret(ssl_encryption_level_t level) const {
    return !levels_[level].write_secret.empty();
  }

  void AllowOutOfOrderWrites() { allow_out_of_order_writes_ = true; }

  bool SetReadSecret(ssl_encryption_level_t level, const SSL_CIPHER *cipher,
                     Span<const uint8_t> secret) {
    if (HasReadSecret(level)) {
      ADD_FAILURE() << LevelToString(level) << " read secret configured twice";
      return false;
    }

    if (role_ == Role::kClient && level == ssl_encryption_early_data) {
      ADD_FAILURE() << "Unexpected early data read secret";
      return false;
    }

    ssl_encryption_level_t ack_level =
        level == ssl_encryption_early_data ? ssl_encryption_application : level;
    if (!HasWriteSecret(ack_level)) {
      ADD_FAILURE() << LevelToString(level)
                    << " read secret configured before ACK write secret";
      return false;
    }

    if (cipher == nullptr) {
      ADD_FAILURE() << "Unexpected null cipher";
      return false;
    }

    if (level != ssl_encryption_early_data &&
        SSL_CIPHER_get_id(cipher) != levels_[level].cipher) {
      ADD_FAILURE() << "Cipher suite inconsistent";
      return false;
    }

    levels_[level].read_secret.assign(secret.begin(), secret.end());
    levels_[level].cipher = SSL_CIPHER_get_id(cipher);
    return true;
  }

  bool SetWriteSecret(ssl_encryption_level_t level, const SSL_CIPHER *cipher,
                      Span<const uint8_t> secret) {
    if (HasWriteSecret(level)) {
      ADD_FAILURE() << LevelToString(level) << " write secret configured twice";
      return false;
    }

    if (role_ == Role::kServer && level == ssl_encryption_early_data) {
      ADD_FAILURE() << "Unexpected early data write secret";
      return false;
    }

    if (cipher == nullptr) {
      ADD_FAILURE() << "Unexpected null cipher";
      return false;
    }

    levels_[level].write_secret.assign(secret.begin(), secret.end());
    levels_[level].cipher = SSL_CIPHER_get_id(cipher);
    return true;
  }

  bool WriteHandshakeData(ssl_encryption_level_t level,
                          Span<const uint8_t> data) {
    if (levels_[level].write_secret.empty()) {
      ADD_FAILURE() << LevelToString(level)
                    << " write secret not yet configured";
      return false;
    }

    // Although the levels are conceptually separate, BoringSSL finishes writing
    // data from a previous level before installing keys for the next level.
    if (!allow_out_of_order_writes_) {
      switch (level) {
        case ssl_encryption_early_data:
          ADD_FAILURE() << "unexpected handshake data at early data level";
          return false;
        case ssl_encryption_initial:
          if (!levels_[ssl_encryption_handshake].write_secret.empty()) {
            ADD_FAILURE()
                << LevelToString(level)
                << " handshake data written after handshake keys installed";
            return false;
          }
          OPENSSL_FALLTHROUGH;
        case ssl_encryption_handshake:
          if (!levels_[ssl_encryption_application].write_secret.empty()) {
            ADD_FAILURE()
                << LevelToString(level)
                << " handshake data written after application keys installed";
            return false;
          }
          OPENSSL_FALLTHROUGH;
        case ssl_encryption_application:
          break;
      }
    }

    levels_[level].write_data.insert(levels_[level].write_data.end(),
                                     data.begin(), data.end());
    return true;
  }

  bool SendAlert(ssl_encryption_level_t level, uint8_t alert_value) {
    if (has_alert_) {
      ADD_FAILURE() << "duplicate alert sent";
      return false;
    }

    if (levels_[level].write_secret.empty()) {
      ADD_FAILURE() << LevelToString(level)
                    << " write secret not yet configured";
      return false;
    }

    has_alert_ = true;
    alert_level_ = level;
    alert_ = alert_value;
    return true;
  }

  bool ReadHandshakeData(std::vector<uint8_t> *out,
                         ssl_encryption_level_t level,
                         size_t num = std::numeric_limits<size_t>::max()) {
    if (levels_[level].read_secret.empty()) {
      ADD_FAILURE() << "data read before keys configured in level " << level;
      return false;
    }
    // The peer may not have configured any keys yet.
    if (peer_->levels_[level].write_secret.empty()) {
      out->clear();
      return true;
    }
    // Check the peer computed the same key.
    if (peer_->levels_[level].write_secret != levels_[level].read_secret) {
      ADD_FAILURE() << "peer write key does not match read key in level "
                    << level;
      return false;
    }
    if (peer_->levels_[level].cipher != levels_[level].cipher) {
      ADD_FAILURE() << "peer cipher does not match in level " << level;
      return false;
    }
    std::vector<uint8_t> *peer_data = &peer_->levels_[level].write_data;
    num = std::min(num, peer_data->size());
    out->assign(peer_data->begin(), peer_data->begin() + num);
    peer_data->erase(peer_data->begin(), peer_data->begin() + num);
    return true;
  }

 private:
  Role role_;
  MockQUICTransport *peer_ = nullptr;

  bool allow_out_of_order_writes_ = false;
  bool has_alert_ = false;
  ssl_encryption_level_t alert_level_ = ssl_encryption_initial;
  uint8_t alert_ = 0;

  struct Level {
    std::vector<uint8_t> write_data;
    std::vector<uint8_t> write_secret;
    std::vector<uint8_t> read_secret;
    uint32_t cipher = 0;
  };
  Level levels_[kNumQUICLevels];
};

class MockQUICTransportPair {
 public:
  MockQUICTransportPair()
      : client_(MockQUICTransport::Role::kClient),
        server_(MockQUICTransport::Role::kServer) {
    client_.set_peer(&server_);
    server_.set_peer(&client_);
  }

  ~MockQUICTransportPair() {
    client_.set_peer(nullptr);
    server_.set_peer(nullptr);
  }

  MockQUICTransport *client() { return &client_; }
  MockQUICTransport *server() { return &server_; }

  bool SecretsMatch(ssl_encryption_level_t level) const {
    // We only need to check |HasReadSecret| and |HasWriteSecret| on |client_|.
    // |PeerSecretsMatch| checks that |server_| is analogously configured.
    return client_.PeerSecretsMatch(level) &&
           client_.HasWriteSecret(level) &&
           (level == ssl_encryption_early_data || client_.HasReadSecret(level));
  }

 private:
  MockQUICTransport client_;
  MockQUICTransport server_;
};

class QUICMethodTest : public testing::Test {
 protected:
  void SetUp() override {
    client_ctx_.reset(SSL_CTX_new(TLS_method()));
    server_ctx_.reset(SSL_CTX_new(TLS_method()));
    ASSERT_TRUE(client_ctx_);
    ASSERT_TRUE(server_ctx_);

    bssl::UniquePtr<X509> cert = GetTestCertificate();
    bssl::UniquePtr<EVP_PKEY> key = GetTestKey();
    ASSERT_TRUE(cert);
    ASSERT_TRUE(key);
    ASSERT_TRUE(SSL_CTX_use_certificate(server_ctx_.get(), cert.get()));
    ASSERT_TRUE(SSL_CTX_use_PrivateKey(server_ctx_.get(), key.get()));

    SSL_CTX_set_min_proto_version(server_ctx_.get(), TLS1_3_VERSION);
    SSL_CTX_set_max_proto_version(server_ctx_.get(), TLS1_3_VERSION);
    SSL_CTX_set_min_proto_version(client_ctx_.get(), TLS1_3_VERSION);
    SSL_CTX_set_max_proto_version(client_ctx_.get(), TLS1_3_VERSION);
  }

  static MockQUICTransport *TransportFromSSL(const SSL *ssl) {
    return ex_data_.Get(ssl);
  }

  static bool ProvideHandshakeData(
      SSL *ssl, size_t num = std::numeric_limits<size_t>::max()) {
    MockQUICTransport *transport = TransportFromSSL(ssl);
    ssl_encryption_level_t level = SSL_quic_read_level(ssl);
    std::vector<uint8_t> data;
    return transport->ReadHandshakeData(&data, level, num) &&
           SSL_provide_quic_data(ssl, level, data.data(), data.size());
  }

  void AllowOutOfOrderWrites() {
    allow_out_of_order_writes_ = true;
  }

  bool CreateClientAndServer() {
    client_.reset(SSL_new(client_ctx_.get()));
    server_.reset(SSL_new(server_ctx_.get()));
    if (!client_ || !server_) {
      return false;
    }

    SSL_set_connect_state(client_.get());
    SSL_set_accept_state(server_.get());

    transport_.reset(new MockQUICTransportPair);
    ex_data_.Set(client_.get(), transport_->client());
    ex_data_.Set(server_.get(), transport_->server());
    if (allow_out_of_order_writes_) {
      transport_->client()->AllowOutOfOrderWrites();
      transport_->server()->AllowOutOfOrderWrites();
    }
    return true;
  }

  // CompleteHandshakesForQUIC runs |SSL_do_handshake| on |client_| and
  // |server_| until each completes once. It returns true on success and false
  // on failure.
  bool CompleteHandshakesForQUIC() {
    bool client_done = false, server_done = false;
    while (!client_done || !server_done) {
      if (!client_done) {
        if (!ProvideHandshakeData(client_.get())) {
          ADD_FAILURE() << "ProvideHandshakeData(client_) failed";
          return false;
        }
        int client_ret = SSL_do_handshake(client_.get());
        int client_err = SSL_get_error(client_.get(), client_ret);
        if (client_ret == 1) {
          client_done = true;
        } else if (client_ret != -1 || client_err != SSL_ERROR_WANT_READ) {
          ADD_FAILURE() << "Unexpected client output: " << client_ret << " "
                        << client_err;
          return false;
        }
      }

      if (!server_done) {
        if (!ProvideHandshakeData(server_.get())) {
          ADD_FAILURE() << "ProvideHandshakeData(server_) failed";
          return false;
        }
        int server_ret = SSL_do_handshake(server_.get());
        int server_err = SSL_get_error(server_.get(), server_ret);
        if (server_ret == 1) {
          server_done = true;
        } else if (server_ret != -1 || server_err != SSL_ERROR_WANT_READ) {
          ADD_FAILURE() << "Unexpected server output: " << server_ret << " "
                        << server_err;
          return false;
        }
      }
    }
    return true;
  }

  bssl::UniquePtr<SSL_SESSION> CreateClientSessionForQUIC() {
    g_last_session = nullptr;
    SSL_CTX_sess_set_new_cb(client_ctx_.get(), SaveLastSession);
    if (!CreateClientAndServer() ||
        !CompleteHandshakesForQUIC()) {
      return nullptr;
    }

    // The server sent NewSessionTicket messages in the handshake.
    if (!ProvideHandshakeData(client_.get()) ||
        !SSL_process_quic_post_handshake(client_.get())) {
      return nullptr;
    }

    return std::move(g_last_session);
  }

  void ExpectHandshakeSuccess() {
    EXPECT_TRUE(transport_->SecretsMatch(ssl_encryption_application));
    EXPECT_EQ(ssl_encryption_application, SSL_quic_read_level(client_.get()));
    EXPECT_EQ(ssl_encryption_application, SSL_quic_write_level(client_.get()));
    EXPECT_EQ(ssl_encryption_application, SSL_quic_read_level(server_.get()));
    EXPECT_EQ(ssl_encryption_application, SSL_quic_write_level(server_.get()));
    EXPECT_FALSE(transport_->client()->has_alert());
    EXPECT_FALSE(transport_->server()->has_alert());

    // SSL_do_handshake is now idempotent.
    EXPECT_EQ(SSL_do_handshake(client_.get()), 1);
    EXPECT_EQ(SSL_do_handshake(server_.get()), 1);
  }

  // Returns a default SSL_QUIC_METHOD. Individual methods may be overwritten by
  // the test.
  SSL_QUIC_METHOD DefaultQUICMethod() {
    return SSL_QUIC_METHOD{
        SetReadSecretCallback, SetWriteSecretCallback, AddHandshakeDataCallback,
        FlushFlightCallback,   SendAlertCallback,
    };
  }

  static int SetReadSecretCallback(SSL *ssl, ssl_encryption_level_t level,
                                   const SSL_CIPHER *cipher,
                                   const uint8_t *secret, size_t secret_len) {
    return TransportFromSSL(ssl)->SetReadSecret(
        level, cipher, MakeConstSpan(secret, secret_len));
  }

  static int SetWriteSecretCallback(SSL *ssl, ssl_encryption_level_t level,
                                    const SSL_CIPHER *cipher,
                                    const uint8_t *secret, size_t secret_len) {
    return TransportFromSSL(ssl)->SetWriteSecret(
        level, cipher, MakeConstSpan(secret, secret_len));
  }

  static int AddHandshakeDataCallback(SSL *ssl,
                                      enum ssl_encryption_level_t level,
                                      const uint8_t *data, size_t len) {
    EXPECT_EQ(level, SSL_quic_write_level(ssl));
    return TransportFromSSL(ssl)->WriteHandshakeData(level,
                                                     MakeConstSpan(data, len));
  }

  static int FlushFlightCallback(SSL *ssl) { return 1; }

  static int SendAlertCallback(SSL *ssl, ssl_encryption_level_t level,
                               uint8_t alert) {
    EXPECT_EQ(level, SSL_quic_write_level(ssl));
    return TransportFromSSL(ssl)->SendAlert(level, alert);
  }

  bssl::UniquePtr<SSL_CTX> client_ctx_;
  bssl::UniquePtr<SSL_CTX> server_ctx_;

  static UnownedSSLExData<MockQUICTransport> ex_data_;
  std::unique_ptr<MockQUICTransportPair> transport_;

  bssl::UniquePtr<SSL> client_;
  bssl::UniquePtr<SSL> server_;

  bool allow_out_of_order_writes_ = false;
};

UnownedSSLExData<MockQUICTransport> QUICMethodTest::ex_data_;

// Test a full handshake and resumption work.
TEST_F(QUICMethodTest, Basic) {
  const SSL_QUIC_METHOD quic_method = DefaultQUICMethod();

  g_last_session = nullptr;

  SSL_CTX_set_session_cache_mode(client_ctx_.get(), SSL_SESS_CACHE_BOTH);
  SSL_CTX_sess_set_new_cb(client_ctx_.get(), SaveLastSession);
  ASSERT_TRUE(SSL_CTX_set_quic_method(client_ctx_.get(), &quic_method));
  ASSERT_TRUE(SSL_CTX_set_quic_method(server_ctx_.get(), &quic_method));

  ASSERT_TRUE(CreateClientAndServer());
  ASSERT_TRUE(CompleteHandshakesForQUIC());

  ExpectHandshakeSuccess();
  EXPECT_FALSE(SSL_session_reused(client_.get()));
  EXPECT_FALSE(SSL_session_reused(server_.get()));

  // The server sent NewSessionTicket messages in the handshake.
  EXPECT_FALSE(g_last_session);
  ASSERT_TRUE(ProvideHandshakeData(client_.get()));
  EXPECT_EQ(SSL_process_quic_post_handshake(client_.get()), 1);
  EXPECT_TRUE(g_last_session);

  // Create a second connection to verify resumption works.
  ASSERT_TRUE(CreateClientAndServer());
  bssl::UniquePtr<SSL_SESSION> session = std::move(g_last_session);
  SSL_set_session(client_.get(), session.get());

  ASSERT_TRUE(CompleteHandshakesForQUIC());

  ExpectHandshakeSuccess();
  EXPECT_TRUE(SSL_session_reused(client_.get()));
  EXPECT_TRUE(SSL_session_reused(server_.get()));
}

// Test that HelloRetryRequest in QUIC works.
TEST_F(QUICMethodTest, HelloRetryRequest) {
  const SSL_QUIC_METHOD quic_method = DefaultQUICMethod();

  ASSERT_TRUE(SSL_CTX_set_quic_method(client_ctx_.get(), &quic_method));
  ASSERT_TRUE(SSL_CTX_set_quic_method(server_ctx_.get(), &quic_method));

  // BoringSSL predicts the most preferred curve, so using different preferences
  // will trigger HelloRetryRequest.
  static const int kClientPrefs[] = {NID_X25519, NID_X9_62_prime256v1};
  ASSERT_TRUE(SSL_CTX_set1_curves(client_ctx_.get(), kClientPrefs,
                                  OPENSSL_ARRAY_SIZE(kClientPrefs)));
  static const int kServerPrefs[] = {NID_X9_62_prime256v1, NID_X25519};
  ASSERT_TRUE(SSL_CTX_set1_curves(server_ctx_.get(), kServerPrefs,
                                  OPENSSL_ARRAY_SIZE(kServerPrefs)));

  ASSERT_TRUE(CreateClientAndServer());
  ASSERT_TRUE(CompleteHandshakesForQUIC());
  ExpectHandshakeSuccess();
}

// Test that, even in a 1-RTT handshake, the server installs keys at the right
// time. Half-RTT keys are available early, but 1-RTT read keys are deferred.
TEST_F(QUICMethodTest, HalfRTTKeys) {
  const SSL_QUIC_METHOD quic_method = DefaultQUICMethod();

  ASSERT_TRUE(SSL_CTX_set_quic_method(client_ctx_.get(), &quic_method));
  ASSERT_TRUE(SSL_CTX_set_quic_method(server_ctx_.get(), &quic_method));
  ASSERT_TRUE(CreateClientAndServer());

  // The client sends ClientHello.
  ASSERT_EQ(SSL_do_handshake(client_.get()), -1);
  ASSERT_EQ(SSL_ERROR_WANT_READ, SSL_get_error(client_.get(), -1));

  // The server reads ClientHello and sends ServerHello..Finished.
  ASSERT_TRUE(ProvideHandshakeData(server_.get()));
  ASSERT_EQ(SSL_do_handshake(server_.get()), -1);
  ASSERT_EQ(SSL_ERROR_WANT_READ, SSL_get_error(server_.get(), -1));

  // At this point, the server has half-RTT write keys, but it cannot access
  // 1-RTT read keys until client Finished.
  EXPECT_TRUE(transport_->server()->HasWriteSecret(ssl_encryption_application));
  EXPECT_FALSE(transport_->server()->HasReadSecret(ssl_encryption_application));

  // Finish up the client and server handshakes.
  ASSERT_TRUE(CompleteHandshakesForQUIC());

  // Both sides can now exchange 1-RTT data.
  ExpectHandshakeSuccess();
}

TEST_F(QUICMethodTest, ZeroRTTAccept) {
  const SSL_QUIC_METHOD quic_method = DefaultQUICMethod();

  SSL_CTX_set_session_cache_mode(client_ctx_.get(), SSL_SESS_CACHE_BOTH);
  SSL_CTX_set_early_data_enabled(client_ctx_.get(), 1);
  SSL_CTX_set_early_data_enabled(server_ctx_.get(), 1);
  ASSERT_TRUE(SSL_CTX_set_quic_method(client_ctx_.get(), &quic_method));
  ASSERT_TRUE(SSL_CTX_set_quic_method(server_ctx_.get(), &quic_method));

  bssl::UniquePtr<SSL_SESSION> session = CreateClientSessionForQUIC();
  ASSERT_TRUE(session);

  ASSERT_TRUE(CreateClientAndServer());
  SSL_set_session(client_.get(), session.get());

  // The client handshake should return immediately into the early data state.
  ASSERT_EQ(SSL_do_handshake(client_.get()), 1);
  EXPECT_TRUE(SSL_in_early_data(client_.get()));
  // The transport should have keys for sending 0-RTT data.
  EXPECT_TRUE(transport_->client()->HasWriteSecret(ssl_encryption_early_data));

  // The server will consume the ClientHello and also enter the early data
  // state.
  ASSERT_TRUE(ProvideHandshakeData(server_.get()));
  ASSERT_EQ(SSL_do_handshake(server_.get()), 1);
  EXPECT_TRUE(SSL_in_early_data(server_.get()));
  EXPECT_TRUE(transport_->SecretsMatch(ssl_encryption_early_data));
  // At this point, the server has half-RTT write keys, but it cannot access
  // 1-RTT read keys until client Finished.
  EXPECT_TRUE(transport_->server()->HasWriteSecret(ssl_encryption_application));
  EXPECT_FALSE(transport_->server()->HasReadSecret(ssl_encryption_application));

  // Finish up the client and server handshakes.
  ASSERT_TRUE(CompleteHandshakesForQUIC());

  // Both sides can now exchange 1-RTT data.
  ExpectHandshakeSuccess();
  EXPECT_TRUE(SSL_session_reused(client_.get()));
  EXPECT_TRUE(SSL_session_reused(server_.get()));
  EXPECT_FALSE(SSL_in_early_data(client_.get()));
  EXPECT_FALSE(SSL_in_early_data(server_.get()));
  EXPECT_TRUE(SSL_early_data_accepted(client_.get()));
  EXPECT_TRUE(SSL_early_data_accepted(server_.get()));
}

TEST_F(QUICMethodTest, ZeroRTTReject) {
  const SSL_QUIC_METHOD quic_method = DefaultQUICMethod();

  SSL_CTX_set_session_cache_mode(client_ctx_.get(), SSL_SESS_CACHE_BOTH);
  SSL_CTX_set_early_data_enabled(client_ctx_.get(), 1);
  SSL_CTX_set_early_data_enabled(server_ctx_.get(), 1);
  ASSERT_TRUE(SSL_CTX_set_quic_method(client_ctx_.get(), &quic_method));
  ASSERT_TRUE(SSL_CTX_set_quic_method(server_ctx_.get(), &quic_method));

  bssl::UniquePtr<SSL_SESSION> session = CreateClientSessionForQUIC();
  ASSERT_TRUE(session);

  for (bool reject_hrr : {false, true}) {
    SCOPED_TRACE(reject_hrr);

    ASSERT_TRUE(CreateClientAndServer());
    if (reject_hrr) {
      // Configure the server to prefer P-256, which will reject 0-RTT via
      // HelloRetryRequest.
      int p256 = NID_X9_62_prime256v1;
      ASSERT_TRUE(SSL_set1_curves(server_.get(), &p256, 1));
    } else {
      // Disable 0-RTT on the server, so it will reject it.
      SSL_set_early_data_enabled(server_.get(), 0);
    }
    SSL_set_session(client_.get(), session.get());

    // The client handshake should return immediately into the early data state.
    ASSERT_EQ(SSL_do_handshake(client_.get()), 1);
    EXPECT_TRUE(SSL_in_early_data(client_.get()));
    // The transport should have keys for sending 0-RTT data.
    EXPECT_TRUE(
        transport_->client()->HasWriteSecret(ssl_encryption_early_data));

    // The server will consume the ClientHello, but it will not accept 0-RTT.
    ASSERT_TRUE(ProvideHandshakeData(server_.get()));
    ASSERT_EQ(SSL_do_handshake(server_.get()), -1);
    EXPECT_EQ(SSL_ERROR_WANT_READ, SSL_get_error(server_.get(), -1));
    EXPECT_FALSE(SSL_in_early_data(server_.get()));
    EXPECT_FALSE(
        transport_->server()->HasReadSecret(ssl_encryption_early_data));

    // The client consumes the server response and signals 0-RTT rejection.
    for (;;) {
      ASSERT_TRUE(ProvideHandshakeData(client_.get()));
      ASSERT_EQ(-1, SSL_do_handshake(client_.get()));
      int err = SSL_get_error(client_.get(), -1);
      if (err == SSL_ERROR_EARLY_DATA_REJECTED) {
        break;
      }
      ASSERT_EQ(SSL_ERROR_WANT_READ, err);
    }

    // As in TLS over TCP, 0-RTT rejection is sticky.
    ASSERT_EQ(-1, SSL_do_handshake(client_.get()));
    ASSERT_EQ(SSL_ERROR_EARLY_DATA_REJECTED, SSL_get_error(client_.get(), -1));

    // Finish up the client and server handshakes.
    SSL_reset_early_data_reject(client_.get());
    ASSERT_TRUE(CompleteHandshakesForQUIC());

    // Both sides can now exchange 1-RTT data.
    ExpectHandshakeSuccess();
    EXPECT_TRUE(SSL_session_reused(client_.get()));
    EXPECT_TRUE(SSL_session_reused(server_.get()));
    EXPECT_FALSE(SSL_in_early_data(client_.get()));
    EXPECT_FALSE(SSL_in_early_data(server_.get()));
    EXPECT_FALSE(SSL_early_data_accepted(client_.get()));
    EXPECT_FALSE(SSL_early_data_accepted(server_.get()));
  }
}

TEST_F(QUICMethodTest, NoZeroRTTKeysBeforeReverify) {
  const SSL_QUIC_METHOD quic_method = DefaultQUICMethod();

  SSL_CTX_set_session_cache_mode(client_ctx_.get(), SSL_SESS_CACHE_BOTH);
  SSL_CTX_set_early_data_enabled(client_ctx_.get(), 1);
  SSL_CTX_set_reverify_on_resume(client_ctx_.get(), 1);
  SSL_CTX_set_early_data_enabled(server_ctx_.get(), 1);
  ASSERT_TRUE(SSL_CTX_set_quic_method(client_ctx_.get(), &quic_method));
  ASSERT_TRUE(SSL_CTX_set_quic_method(server_ctx_.get(), &quic_method));

  bssl::UniquePtr<SSL_SESSION> session = CreateClientSessionForQUIC();
  ASSERT_TRUE(session);

  ASSERT_TRUE(CreateClientAndServer());
  SSL_set_session(client_.get(), session.get());

  // Configure the certificate (re)verification to never complete. The client
  // handshake should pause.
  SSL_set_custom_verify(
      client_.get(), SSL_VERIFY_PEER,
      [](SSL *ssl, uint8_t *out_alert) -> ssl_verify_result_t {
        return ssl_verify_retry;
      });
  ASSERT_EQ(SSL_do_handshake(client_.get()), -1);
  ASSERT_EQ(SSL_get_error(client_.get(), -1),
            SSL_ERROR_WANT_CERTIFICATE_VERIFY);

  // The early data keys have not yet been released.
  EXPECT_FALSE(transport_->client()->HasWriteSecret(ssl_encryption_early_data));

  // After the verification completes, the handshake progresses to the 0-RTT
  // point and releases keys.
  SSL_set_custom_verify(
      client_.get(), SSL_VERIFY_PEER,
      [](SSL *ssl, uint8_t *out_alert) -> ssl_verify_result_t {
        return ssl_verify_ok;
      });
  ASSERT_EQ(SSL_do_handshake(client_.get()), 1);
  EXPECT_TRUE(SSL_in_early_data(client_.get()));
  EXPECT_TRUE(transport_->client()->HasWriteSecret(ssl_encryption_early_data));
}

// Test only releasing data to QUIC one byte at a time on request, to maximize
// state machine pauses. Additionally, test that existing asynchronous callbacks
// still work.
TEST_F(QUICMethodTest, Async) {
  const SSL_QUIC_METHOD quic_method = DefaultQUICMethod();

  ASSERT_TRUE(SSL_CTX_set_quic_method(client_ctx_.get(), &quic_method));
  ASSERT_TRUE(SSL_CTX_set_quic_method(server_ctx_.get(), &quic_method));
  ASSERT_TRUE(CreateClientAndServer());

  // Install an asynchronous certificate callback.
  bool cert_cb_ok = false;
  SSL_set_cert_cb(server_.get(),
                  [](SSL *, void *arg) -> int {
                    return *static_cast<bool *>(arg) ? 1 : -1;
                  },
                  &cert_cb_ok);

  for (;;) {
    int client_ret = SSL_do_handshake(client_.get());
    if (client_ret != 1) {
      ASSERT_EQ(client_ret, -1);
      ASSERT_EQ(SSL_get_error(client_.get(), client_ret), SSL_ERROR_WANT_READ);
      ASSERT_TRUE(ProvideHandshakeData(client_.get(), 1));
    }

    int server_ret = SSL_do_handshake(server_.get());
    if (server_ret != 1) {
      ASSERT_EQ(server_ret, -1);
      int ssl_err = SSL_get_error(server_.get(), server_ret);
      switch (ssl_err) {
        case SSL_ERROR_WANT_READ:
          ASSERT_TRUE(ProvideHandshakeData(server_.get(), 1));
          break;
        case SSL_ERROR_WANT_X509_LOOKUP:
          ASSERT_FALSE(cert_cb_ok);
          cert_cb_ok = true;
          break;
        default:
          FAIL() << "Unexpected SSL_get_error result: " << ssl_err;
      }
    }

    if (client_ret == 1 && server_ret == 1) {
      break;
    }
  }

  ExpectHandshakeSuccess();
}

// Test buffering write data until explicit flushes.
TEST_F(QUICMethodTest, Buffered) {
  AllowOutOfOrderWrites();

  struct BufferedFlight {
    std::vector<uint8_t> data[kNumQUICLevels];
  };
  static UnownedSSLExData<BufferedFlight> buffered_flights;

  auto add_handshake_data = [](SSL *ssl, enum ssl_encryption_level_t level,
                               const uint8_t *data, size_t len) -> int {
    BufferedFlight *flight = buffered_flights.Get(ssl);
    flight->data[level].insert(flight->data[level].end(), data, data + len);
    return 1;
  };

  auto flush_flight = [](SSL *ssl) -> int {
    BufferedFlight *flight = buffered_flights.Get(ssl);
    for (size_t level = 0; level < kNumQUICLevels; level++) {
      if (!flight->data[level].empty()) {
        if (!TransportFromSSL(ssl)->WriteHandshakeData(
                static_cast<ssl_encryption_level_t>(level),
                flight->data[level])) {
          return 0;
        }
        flight->data[level].clear();
      }
    }
    return 1;
  };

  SSL_QUIC_METHOD quic_method = DefaultQUICMethod();
  quic_method.add_handshake_data = add_handshake_data;
  quic_method.flush_flight = flush_flight;

  ASSERT_TRUE(SSL_CTX_set_quic_method(client_ctx_.get(), &quic_method));
  ASSERT_TRUE(SSL_CTX_set_quic_method(server_ctx_.get(), &quic_method));
  ASSERT_TRUE(CreateClientAndServer());

  BufferedFlight client_flight, server_flight;
  buffered_flights.Set(client_.get(), &client_flight);
  buffered_flights.Set(server_.get(), &server_flight);

  ASSERT_TRUE(CompleteHandshakesForQUIC());

  ExpectHandshakeSuccess();
}

// Test that excess data at one level is rejected. That is, if a single
// |SSL_provide_quic_data| call included both ServerHello and
// EncryptedExtensions in a single chunk, BoringSSL notices and rejects this on
// key change.
TEST_F(QUICMethodTest, ExcessProvidedData) {
  AllowOutOfOrderWrites();

  auto add_handshake_data = [](SSL *ssl, enum ssl_encryption_level_t level,
                               const uint8_t *data, size_t len) -> int {
    // Switch everything to the initial level.
    return TransportFromSSL(ssl)->WriteHandshakeData(ssl_encryption_initial,
                                                     MakeConstSpan(data, len));
  };

  SSL_QUIC_METHOD quic_method = DefaultQUICMethod();
  quic_method.add_handshake_data = add_handshake_data;

  ASSERT_TRUE(SSL_CTX_set_quic_method(client_ctx_.get(), &quic_method));
  ASSERT_TRUE(SSL_CTX_set_quic_method(server_ctx_.get(), &quic_method));
  ASSERT_TRUE(CreateClientAndServer());

  // Send the ClientHello and ServerHello through Finished.
  ASSERT_EQ(SSL_do_handshake(client_.get()), -1);
  ASSERT_EQ(SSL_get_error(client_.get(), -1), SSL_ERROR_WANT_READ);
  ASSERT_TRUE(ProvideHandshakeData(server_.get()));
  ASSERT_EQ(SSL_do_handshake(server_.get()), -1);
  ASSERT_EQ(SSL_get_error(server_.get(), -1), SSL_ERROR_WANT_READ);

  // The client is still waiting for the ServerHello at initial
  // encryption.
  ASSERT_EQ(ssl_encryption_initial, SSL_quic_read_level(client_.get()));

  // |add_handshake_data| incorrectly wrote everything at the initial level, so
  // this queues up ServerHello through Finished in one chunk.
  ASSERT_TRUE(ProvideHandshakeData(client_.get()));

  // The client reads ServerHello successfully, but then rejects the buffered
  // EncryptedExtensions on key change.
  ASSERT_EQ(SSL_do_handshake(client_.get()), -1);
  ASSERT_EQ(SSL_get_error(client_.get(), -1), SSL_ERROR_SSL);
  uint32_t err = ERR_get_error();
  EXPECT_EQ(ERR_GET_LIB(err), ERR_LIB_SSL);
  EXPECT_EQ(ERR_GET_REASON(err), SSL_R_EXCESS_HANDSHAKE_DATA);

  // The client sends an alert in response to this. The alert is sent at
  // handshake level because we install write secrets before read secrets and
  // the error is discovered when installing the read secret. (How to send
  // alerts on protocol syntax errors near key changes is ambiguous in general.)
  ASSERT_TRUE(transport_->client()->has_alert());
  EXPECT_EQ(transport_->client()->alert_level(), ssl_encryption_handshake);
  EXPECT_EQ(transport_->client()->alert(), SSL_AD_UNEXPECTED_MESSAGE);

  // Sanity-check handshake secrets. The error is discovered while setting the
  // read secret, so only the write secret has been installed.
  EXPECT_TRUE(transport_->client()->HasWriteSecret(ssl_encryption_handshake));
  EXPECT_FALSE(transport_->client()->HasReadSecret(ssl_encryption_handshake));
}

// Test that |SSL_provide_quic_data| will reject data at the wrong level.
TEST_F(QUICMethodTest, ProvideWrongLevel) {
  const SSL_QUIC_METHOD quic_method = DefaultQUICMethod();

  ASSERT_TRUE(SSL_CTX_set_quic_method(client_ctx_.get(), &quic_method));
  ASSERT_TRUE(SSL_CTX_set_quic_method(server_ctx_.get(), &quic_method));
  ASSERT_TRUE(CreateClientAndServer());

  // Send the ClientHello and ServerHello through Finished.
  ASSERT_EQ(SSL_do_handshake(client_.get()), -1);
  ASSERT_EQ(SSL_get_error(client_.get(), -1), SSL_ERROR_WANT_READ);
  ASSERT_TRUE(ProvideHandshakeData(server_.get()));
  ASSERT_EQ(SSL_do_handshake(server_.get()), -1);
  ASSERT_EQ(SSL_get_error(server_.get(), -1), SSL_ERROR_WANT_READ);

  // The client is still waiting for the ServerHello at initial
  // encryption.
  ASSERT_EQ(ssl_encryption_initial, SSL_quic_read_level(client_.get()));

  // Data cannot be provided at the next level.
  std::vector<uint8_t> data;
  ASSERT_TRUE(
      transport_->client()->ReadHandshakeData(&data, ssl_encryption_initial));
  ASSERT_FALSE(SSL_provide_quic_data(client_.get(), ssl_encryption_handshake,
                                     data.data(), data.size()));
  ERR_clear_error();

  // Progress to EncryptedExtensions.
  ASSERT_TRUE(SSL_provide_quic_data(client_.get(), ssl_encryption_initial,
                                    data.data(), data.size()));
  ASSERT_EQ(SSL_do_handshake(client_.get()), -1);
  ASSERT_EQ(SSL_get_error(client_.get(), -1), SSL_ERROR_WANT_READ);
  ASSERT_EQ(ssl_encryption_handshake, SSL_quic_read_level(client_.get()));

  // Data cannot be provided at the previous level.
  ASSERT_TRUE(
      transport_->client()->ReadHandshakeData(&data, ssl_encryption_handshake));
  ASSERT_FALSE(SSL_provide_quic_data(client_.get(), ssl_encryption_initial,
                                     data.data(), data.size()));
}

TEST_F(QUICMethodTest, TooMuchData) {
  const SSL_QUIC_METHOD quic_method = DefaultQUICMethod();

  ASSERT_TRUE(SSL_CTX_set_quic_method(client_ctx_.get(), &quic_method));
  ASSERT_TRUE(SSL_CTX_set_quic_method(server_ctx_.get(), &quic_method));
  ASSERT_TRUE(CreateClientAndServer());

  size_t limit =
      SSL_quic_max_handshake_flight_len(client_.get(), ssl_encryption_initial);
  uint8_t b = 0;
  for (size_t i = 0; i < limit; i++) {
    ASSERT_TRUE(
        SSL_provide_quic_data(client_.get(), ssl_encryption_initial, &b, 1));
  }

  EXPECT_FALSE(
      SSL_provide_quic_data(client_.get(), ssl_encryption_initial, &b, 1));
}

// Provide invalid post-handshake data.
TEST_F(QUICMethodTest, BadPostHandshake) {
  const SSL_QUIC_METHOD quic_method = DefaultQUICMethod();

  g_last_session = nullptr;

  SSL_CTX_set_session_cache_mode(client_ctx_.get(), SSL_SESS_CACHE_BOTH);
  SSL_CTX_sess_set_new_cb(client_ctx_.get(), SaveLastSession);
  ASSERT_TRUE(SSL_CTX_set_quic_method(client_ctx_.get(), &quic_method));
  ASSERT_TRUE(SSL_CTX_set_quic_method(server_ctx_.get(), &quic_method));
  ASSERT_TRUE(CreateClientAndServer());
  ASSERT_TRUE(CompleteHandshakesForQUIC());

  EXPECT_EQ(SSL_do_handshake(client_.get()), 1);
  EXPECT_EQ(SSL_do_handshake(server_.get()), 1);
  EXPECT_TRUE(transport_->SecretsMatch(ssl_encryption_application));
  EXPECT_FALSE(transport_->client()->has_alert());
  EXPECT_FALSE(transport_->server()->has_alert());

  // Junk sent as part of post-handshake data should cause an error.
  uint8_t kJunk[] = {0x17, 0x0, 0x0, 0x4, 0xB, 0xE, 0xE, 0xF};
  ASSERT_TRUE(SSL_provide_quic_data(client_.get(), ssl_encryption_application,
                                    kJunk, sizeof(kJunk)));
  EXPECT_EQ(SSL_process_quic_post_handshake(client_.get()), 0);
}

static void ExpectReceivedTransportParamsEqual(const SSL *ssl,
                                               Span<const uint8_t> expected) {
  const uint8_t *received;
  size_t received_len;
  SSL_get_peer_quic_transport_params(ssl, &received, &received_len);
  ASSERT_EQ(received_len, expected.size());
  EXPECT_EQ(Bytes(received, received_len), Bytes(expected));
}

TEST_F(QUICMethodTest, SetTransportParameters) {
  const SSL_QUIC_METHOD quic_method = DefaultQUICMethod();
  ASSERT_TRUE(SSL_CTX_set_quic_method(client_ctx_.get(), &quic_method));
  ASSERT_TRUE(SSL_CTX_set_quic_method(server_ctx_.get(), &quic_method));

  ASSERT_TRUE(CreateClientAndServer());
  uint8_t kClientParams[] = {1, 2, 3, 4};
  uint8_t kServerParams[] = {5, 6, 7};
  ASSERT_TRUE(SSL_set_quic_transport_params(client_.get(), kClientParams,
                                            sizeof(kClientParams)));
  ASSERT_TRUE(SSL_set_quic_transport_params(server_.get(), kServerParams,
                                            sizeof(kServerParams)));

  ASSERT_TRUE(CompleteHandshakesForQUIC());
  ExpectReceivedTransportParamsEqual(client_.get(), kServerParams);
  ExpectReceivedTransportParamsEqual(server_.get(), kClientParams);
}

TEST_F(QUICMethodTest, SetTransportParamsInCallback) {
  const SSL_QUIC_METHOD quic_method = DefaultQUICMethod();
  ASSERT_TRUE(SSL_CTX_set_quic_method(client_ctx_.get(), &quic_method));
  ASSERT_TRUE(SSL_CTX_set_quic_method(server_ctx_.get(), &quic_method));

  ASSERT_TRUE(CreateClientAndServer());
  uint8_t kClientParams[] = {1, 2, 3, 4};
  static uint8_t kServerParams[] = {5, 6, 7};
  ASSERT_TRUE(SSL_set_quic_transport_params(client_.get(), kClientParams,
                                            sizeof(kClientParams)));
  SSL_CTX_set_tlsext_servername_callback(
      server_ctx_.get(), [](SSL *ssl, int *out_alert, void *arg) -> int {
        EXPECT_TRUE(SSL_set_quic_transport_params(ssl, kServerParams,
                                                  sizeof(kServerParams)));
        return SSL_TLSEXT_ERR_OK;
      });

  ASSERT_TRUE(CompleteHandshakesForQUIC());
  ExpectReceivedTransportParamsEqual(client_.get(), kServerParams);
  ExpectReceivedTransportParamsEqual(server_.get(), kClientParams);
}

extern "C" {
int BORINGSSL_enum_c_type_test(void);
}

TEST(SSLTest, EnumTypes) {
  EXPECT_EQ(sizeof(int), sizeof(ssl_private_key_result_t));
  EXPECT_EQ(1, BORINGSSL_enum_c_type_test());
}

TEST_P(SSLVersionTest, DoubleSSLError) {
  // Connect the inner SSL connections.
  ASSERT_TRUE(Connect());

  // Make a pair of |BIO|s which wrap |client_| and |server_|.
  UniquePtr<BIO_METHOD> bio_method(BIO_meth_new(0, nullptr));
  ASSERT_TRUE(bio_method);
  ASSERT_TRUE(BIO_meth_set_read(
      bio_method.get(), [](BIO *bio, char *out, int len) -> int {
        SSL *ssl = static_cast<SSL *>(BIO_get_data(bio));
        int ret = SSL_read(ssl, out, len);
        int ssl_ret = SSL_get_error(ssl, ret);
        if (ssl_ret == SSL_ERROR_WANT_READ) {
          BIO_set_retry_read(bio);
        }
        return ret;
      }));
  ASSERT_TRUE(BIO_meth_set_write(
      bio_method.get(), [](BIO *bio, const char *in, int len) -> int {
        SSL *ssl = static_cast<SSL *>(BIO_get_data(bio));
        int ret = SSL_write(ssl, in, len);
        int ssl_ret = SSL_get_error(ssl, ret);
        if (ssl_ret == SSL_ERROR_WANT_WRITE) {
          BIO_set_retry_write(bio);
        }
        return ret;
      }));
  ASSERT_TRUE(BIO_meth_set_ctrl(
      bio_method.get(), [](BIO *bio, int cmd, long larg, void *parg) -> long {
        // |SSL| objects require |BIO_flush| support.
        if (cmd == BIO_CTRL_FLUSH) {
          return 1;
        }
        return 0;
      }));

  UniquePtr<BIO> client_bio(BIO_new(bio_method.get()));
  ASSERT_TRUE(client_bio);
  BIO_set_data(client_bio.get(), client_.get());
  BIO_set_init(client_bio.get(), 1);

  UniquePtr<BIO> server_bio(BIO_new(bio_method.get()));
  ASSERT_TRUE(server_bio);
  BIO_set_data(server_bio.get(), server_.get());
  BIO_set_init(server_bio.get(), 1);

  // Wrap the inner connections in another layer of SSL.
  UniquePtr<SSL> client_outer(SSL_new(client_ctx_.get()));
  ASSERT_TRUE(client_outer);
  SSL_set_connect_state(client_outer.get());
  SSL_set_bio(client_outer.get(), client_bio.get(), client_bio.get());
  client_bio.release();  // |SSL_set_bio| takes ownership.

  UniquePtr<SSL> server_outer(SSL_new(server_ctx_.get()));
  ASSERT_TRUE(server_outer);
  SSL_set_accept_state(server_outer.get());
  SSL_set_bio(server_outer.get(), server_bio.get(), server_bio.get());
  server_bio.release();  // |SSL_set_bio| takes ownership.

  // Configure |client_outer| to reject the server certificate.
  SSL_set_custom_verify(
      client_outer.get(), SSL_VERIFY_PEER,
      [](SSL *ssl, uint8_t *out_alert) -> ssl_verify_result_t {
        return ssl_verify_invalid;
      });

  for (;;) {
    int client_ret = SSL_do_handshake(client_outer.get());
    int client_err = SSL_get_error(client_outer.get(), client_ret);
    if (client_err != SSL_ERROR_WANT_READ &&
        client_err != SSL_ERROR_WANT_WRITE) {
      // The client handshake should terminate on a certificate verification
      // error.
      EXPECT_EQ(SSL_ERROR_SSL, client_err);
      uint32_t err = ERR_peek_error();
      EXPECT_EQ(ERR_LIB_SSL, ERR_GET_LIB(err));
      EXPECT_EQ(SSL_R_CERTIFICATE_VERIFY_FAILED, ERR_GET_REASON(err));
      break;
    }

    // Run the server handshake and continue.
    int server_ret = SSL_do_handshake(server_outer.get());
    int server_err = SSL_get_error(server_outer.get(), server_ret);
    ASSERT_TRUE(server_err == SSL_ERROR_NONE ||
                server_err == SSL_ERROR_WANT_READ ||
                server_err == SSL_ERROR_WANT_WRITE);
  }
}

TEST(SSLTest, WriteWhileExplicitRenegotiate) {
  bssl::UniquePtr<SSL_CTX> ctx(SSL_CTX_new(TLS_method()));
  ASSERT_TRUE(ctx);

  bssl::UniquePtr<X509> cert = GetTestCertificate();
  bssl::UniquePtr<EVP_PKEY> pkey = GetTestKey();
  ASSERT_TRUE(cert);
  ASSERT_TRUE(pkey);
  ASSERT_TRUE(SSL_CTX_use_certificate(ctx.get(), cert.get()));
  ASSERT_TRUE(SSL_CTX_use_PrivateKey(ctx.get(), pkey.get()));
  ASSERT_TRUE(SSL_CTX_set_min_proto_version(ctx.get(), TLS1_2_VERSION));
  ASSERT_TRUE(SSL_CTX_set_max_proto_version(ctx.get(), TLS1_2_VERSION));
  ASSERT_TRUE(SSL_CTX_set_strict_cipher_list(
      ctx.get(), "TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256"));

  bssl::UniquePtr<SSL> client, server;
  ASSERT_TRUE(ConnectClientAndServer(&client, &server, ctx.get(), ctx.get(),
                                     ClientConfig(), true /* do_handshake */,
                                     false /* don't shed handshake config */));
  SSL_set_renegotiate_mode(client.get(), ssl_renegotiate_explicit);

  static const uint8_t kInput[] = {'h', 'e', 'l', 'l', 'o'};

  // Write "hello" until the buffer is full, so |client| has a pending write.
  size_t num_writes = 0;
  for (;;) {
    int ret = SSL_write(client.get(), kInput, sizeof(kInput));
    if (ret != int(sizeof(kInput))) {
      ASSERT_EQ(-1, ret);
      ASSERT_EQ(SSL_ERROR_WANT_WRITE, SSL_get_error(client.get(), ret));
      break;
    }
    num_writes++;
  }

  // Encrypt a HelloRequest.
  uint8_t in[] = {SSL3_MT_HELLO_REQUEST, 0, 0, 0};
#if defined(BORINGSSL_UNSAFE_FUZZER_MODE)
  // Fuzzer-mode records are unencrypted.
  uint8_t record[5 + sizeof(in)];
  record[0] = SSL3_RT_HANDSHAKE;
  record[1] = 3;
  record[2] = 3;  // TLS 1.2
  record[3] = 0;
  record[4] = sizeof(record) - 5;
  memcpy(record + 5, in, sizeof(in));
#else
  // Extract key material from |server|.
  static const size_t kKeyLen = 32;
  static const size_t kNonceLen = 12;
  ASSERT_EQ(2u * (kKeyLen + kNonceLen), SSL_get_key_block_len(server.get()));
  uint8_t key_block[2u * (kKeyLen + kNonceLen)];
  ASSERT_TRUE(
      SSL_generate_key_block(server.get(), key_block, sizeof(key_block)));
  Span<uint8_t> key = MakeSpan(key_block + kKeyLen, kKeyLen);
  Span<uint8_t> nonce =
      MakeSpan(key_block + kKeyLen + kKeyLen + kNonceLen, kNonceLen);

  uint8_t ad[13];
  uint64_t seq = SSL_get_write_sequence(server.get());
  for (size_t i = 0; i < 8; i++) {
    // The nonce is XORed with the sequence number.
    nonce[11 - i] ^= uint8_t(seq);
    ad[7 - i] = uint8_t(seq);
    seq >>= 8;
  }

  ad[8] = SSL3_RT_HANDSHAKE;
  ad[9] = 3;
  ad[10] = 3;  // TLS 1.2
  ad[11] = 0;
  ad[12] = sizeof(in);

  uint8_t record[5 + sizeof(in) + 16];
  record[0] = SSL3_RT_HANDSHAKE;
  record[1] = 3;
  record[2] = 3;  // TLS 1.2
  record[3] = 0;
  record[4] = sizeof(record) - 5;

  ScopedEVP_AEAD_CTX aead;
  ASSERT_TRUE(EVP_AEAD_CTX_init(aead.get(), EVP_aead_chacha20_poly1305(),
                                key.data(), key.size(),
                                EVP_AEAD_DEFAULT_TAG_LENGTH, nullptr));
  size_t len;
  ASSERT_TRUE(EVP_AEAD_CTX_seal(aead.get(), record + 5, &len,
                                sizeof(record) - 5, nonce.data(), nonce.size(),
                                in, sizeof(in), ad, sizeof(ad)));
  ASSERT_EQ(sizeof(record) - 5, len);
#endif  // BORINGSSL_UNSAFE_FUZZER_MODE

  ASSERT_EQ(int(sizeof(record)),
            BIO_write(SSL_get_wbio(server.get()), record, sizeof(record)));

  // |SSL_read| should pick up the HelloRequest.
  uint8_t byte;
  ASSERT_EQ(-1, SSL_read(client.get(), &byte, 1));
  ASSERT_EQ(SSL_ERROR_WANT_RENEGOTIATE, SSL_get_error(client.get(), -1));

  // Drain the data from the |client|.
  uint8_t buf[sizeof(kInput)];
  for (size_t i = 0; i < num_writes; i++) {
    ASSERT_EQ(int(sizeof(buf)), SSL_read(server.get(), buf, sizeof(buf)));
    EXPECT_EQ(Bytes(buf), Bytes(kInput));
  }

  // |client| should be able to finish the pending write and continue to write,
  // despite the paused HelloRequest.
  ASSERT_EQ(int(sizeof(kInput)),
            SSL_write(client.get(), kInput, sizeof(kInput)));
  ASSERT_EQ(int(sizeof(buf)), SSL_read(server.get(), buf, sizeof(buf)));
  EXPECT_EQ(Bytes(buf), Bytes(kInput));

  ASSERT_EQ(int(sizeof(kInput)),
            SSL_write(client.get(), kInput, sizeof(kInput)));
  ASSERT_EQ(int(sizeof(buf)), SSL_read(server.get(), buf, sizeof(buf)));
  EXPECT_EQ(Bytes(buf), Bytes(kInput));

  // |SSL_read| is stuck until we acknowledge the HelloRequest.
  ASSERT_EQ(-1, SSL_read(client.get(), &byte, 1));
  ASSERT_EQ(SSL_ERROR_WANT_RENEGOTIATE, SSL_get_error(client.get(), -1));

  ASSERT_TRUE(SSL_renegotiate(client.get()));
  ASSERT_EQ(-1, SSL_read(client.get(), &byte, 1));
  ASSERT_EQ(SSL_ERROR_WANT_READ, SSL_get_error(client.get(), -1));

  // We never renegotiate as a server.
  ASSERT_EQ(-1, SSL_read(server.get(), buf, sizeof(buf)));
  ASSERT_EQ(SSL_ERROR_SSL, SSL_get_error(server.get(), -1));
  uint32_t err = ERR_get_error();
  EXPECT_EQ(ERR_LIB_SSL, ERR_GET_LIB(err));
  EXPECT_EQ(SSL_R_NO_RENEGOTIATION, ERR_GET_REASON(err));
}

}  // namespace
BSSL_NAMESPACE_END
