/* Copyright (c) 2016, 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 <limits.h>
#include <stdio.h>

#include <string>
#include <vector>

#include <gtest/gtest.h>

#include <openssl/asn1.h>
#include <openssl/asn1t.h>
#include <openssl/bytestring.h>
#include <openssl/err.h>
#include <openssl/mem.h>
#include <openssl/obj.h>
#include <openssl/span.h>
#include <openssl/x509v3.h>

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


// kTag128 is an ASN.1 structure with a universal tag with number 128.
static const uint8_t kTag128[] = {
    0x1f, 0x81, 0x00, 0x01, 0x00,
};

// kTag258 is an ASN.1 structure with a universal tag with number 258.
static const uint8_t kTag258[] = {
    0x1f, 0x82, 0x02, 0x01, 0x00,
};

static_assert(V_ASN1_NEG_INTEGER == 258,
              "V_ASN1_NEG_INTEGER changed. Update kTag258 to collide with it.");

// kTagOverflow is an ASN.1 structure with a universal tag with number 2^35-1,
// which will not fit in an int.
static const uint8_t kTagOverflow[] = {
    0x1f, 0xff, 0xff, 0xff, 0xff, 0x7f, 0x01, 0x00,
};

TEST(ASN1Test, LargeTags) {
  const uint8_t *p = kTag258;
  bssl::UniquePtr<ASN1_TYPE> obj(d2i_ASN1_TYPE(NULL, &p, sizeof(kTag258)));
  EXPECT_FALSE(obj) << "Parsed value with illegal tag" << obj->type;
  ERR_clear_error();

  p = kTagOverflow;
  obj.reset(d2i_ASN1_TYPE(NULL, &p, sizeof(kTagOverflow)));
  EXPECT_FALSE(obj) << "Parsed value with tag overflow" << obj->type;
  ERR_clear_error();

  p = kTag128;
  obj.reset(d2i_ASN1_TYPE(NULL, &p, sizeof(kTag128)));
  ASSERT_TRUE(obj);
  EXPECT_EQ(128, obj->type);
  const uint8_t kZero = 0;
  EXPECT_EQ(Bytes(&kZero, 1), Bytes(obj->value.asn1_string->data,
                                    obj->value.asn1_string->length));
}

TEST(ASN1Test, IntegerSetting) {
  bssl::UniquePtr<ASN1_INTEGER> by_bn(ASN1_INTEGER_new());
  bssl::UniquePtr<ASN1_INTEGER> by_long(ASN1_INTEGER_new());
  bssl::UniquePtr<ASN1_INTEGER> by_uint64(ASN1_INTEGER_new());
  bssl::UniquePtr<BIGNUM> bn(BN_new());

  const std::vector<int64_t> kValues = {
      LONG_MIN, -2, -1, 0, 1, 2, 0xff, 0x100, 0xffff, 0x10000, LONG_MAX,
  };
  for (const auto &i : kValues) {
    SCOPED_TRACE(i);

    ASSERT_EQ(1, ASN1_INTEGER_set(by_long.get(), i));
    const uint64_t abs = i < 0 ? (0 - (uint64_t) i) : i;
    ASSERT_TRUE(BN_set_u64(bn.get(), abs));
    BN_set_negative(bn.get(), i < 0);
    ASSERT_TRUE(BN_to_ASN1_INTEGER(bn.get(), by_bn.get()));

    EXPECT_EQ(0, ASN1_INTEGER_cmp(by_bn.get(), by_long.get()));

    if (i >= 0) {
      ASSERT_EQ(1, ASN1_INTEGER_set_uint64(by_uint64.get(), i));
      EXPECT_EQ(0, ASN1_INTEGER_cmp(by_bn.get(), by_uint64.get()));
    }
  }
}

template <typename T>
void TestSerialize(T obj, int (*i2d_func)(T a, uint8_t **pp),
                   bssl::Span<const uint8_t> expected) {
  // Test the allocating version first. It is easiest to debug.
  uint8_t *ptr = nullptr;
  int len = i2d_func(obj, &ptr);
  ASSERT_GT(len, 0);
  EXPECT_EQ(Bytes(expected), Bytes(ptr, len));
  OPENSSL_free(ptr);

  len = i2d_func(obj, nullptr);
  ASSERT_GT(len, 0);
  EXPECT_EQ(len, static_cast<int>(expected.size()));

  std::vector<uint8_t> buf(len);
  ptr = buf.data();
  len = i2d_func(obj, &ptr);
  ASSERT_EQ(len, static_cast<int>(expected.size()));
  EXPECT_EQ(ptr, buf.data() + buf.size());
  EXPECT_EQ(Bytes(expected), Bytes(buf));
}

TEST(ASN1Test, SerializeObject) {
  static const uint8_t kDER[] = {0x06, 0x09, 0x2a, 0x86, 0x48, 0x86,
                                 0xf7, 0x0d, 0x01, 0x01, 0x01};
  const ASN1_OBJECT *obj = OBJ_nid2obj(NID_rsaEncryption);
  TestSerialize(obj, i2d_ASN1_OBJECT, kDER);
}

TEST(ASN1Test, SerializeBoolean) {
  static const uint8_t kTrue[] = {0x01, 0x01, 0xff};
  TestSerialize(0xff, i2d_ASN1_BOOLEAN, kTrue);
  // Other constants are also correctly encoded as TRUE.
  TestSerialize(1, i2d_ASN1_BOOLEAN, kTrue);
  TestSerialize(0x100, i2d_ASN1_BOOLEAN, kTrue);

  static const uint8_t kFalse[] = {0x01, 0x01, 0x00};
  TestSerialize(0x00, i2d_ASN1_BOOLEAN, kFalse);
}

// The templates go through a different codepath, so test them separately.
TEST(ASN1Test, SerializeEmbeddedBoolean) {
  bssl::UniquePtr<BASIC_CONSTRAINTS> val(BASIC_CONSTRAINTS_new());
  ASSERT_TRUE(val);

  // BasicConstraints defaults to FALSE, so the encoding should be empty.
  static const uint8_t kLeaf[] = {0x30, 0x00};
  val->ca = 0;
  TestSerialize(val.get(), i2d_BASIC_CONSTRAINTS, kLeaf);

  // TRUE should always be encoded as 0xff, independent of what value the caller
  // placed in the |ASN1_BOOLEAN|.
  static const uint8_t kCA[] = {0x30, 0x03, 0x01, 0x01, 0xff};
  val->ca = 0xff;
  TestSerialize(val.get(), i2d_BASIC_CONSTRAINTS, kCA);
  val->ca = 1;
  TestSerialize(val.get(), i2d_BASIC_CONSTRAINTS, kCA);
  val->ca = 0x100;
  TestSerialize(val.get(), i2d_BASIC_CONSTRAINTS, kCA);
}

TEST(ASN1Test, ASN1Type) {
  const struct {
    int type;
    std::vector<uint8_t> der;
  } kTests[] = {
      // BOOLEAN { TRUE }
      {V_ASN1_BOOLEAN, {0x01, 0x01, 0xff}},
      // BOOLEAN { FALSE }
      {V_ASN1_BOOLEAN, {0x01, 0x01, 0x00}},
      // OCTET_STRING { "a" }
      {V_ASN1_OCTET_STRING, {0x04, 0x01, 0x61}},
      // OCTET_STRING { }
      {V_ASN1_OCTET_STRING, {0x04, 0x00}},
      // BIT_STRING { `01` `00` }
      {V_ASN1_BIT_STRING, {0x03, 0x02, 0x01, 0x00}},
      // INTEGER { -1 }
      {V_ASN1_INTEGER, {0x02, 0x01, 0xff}},
      // OBJECT_IDENTIFIER { 1.2.840.113554.4.1.72585.2 }
      {V_ASN1_OBJECT,
       {0x06, 0x0c, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x12, 0x04, 0x01, 0x84, 0xb7,
        0x09, 0x02}},
      // NULL {}
      {V_ASN1_NULL, {0x05, 0x00}},
      // SEQUENCE {}
      {V_ASN1_SEQUENCE, {0x30, 0x00}},
      // SET {}
      {V_ASN1_SET, {0x31, 0x00}},
      // [0] { UTF8String { "a" } }
      {V_ASN1_OTHER, {0xa0, 0x03, 0x0c, 0x01, 0x61}},
  };
  for (const auto &t : kTests) {
    SCOPED_TRACE(Bytes(t.der));

    // The input should successfully parse.
    const uint8_t *ptr = t.der.data();
    bssl::UniquePtr<ASN1_TYPE> val(d2i_ASN1_TYPE(nullptr, &ptr, t.der.size()));
    ASSERT_TRUE(val);

    EXPECT_EQ(ASN1_TYPE_get(val.get()), t.type);
    EXPECT_EQ(val->type, t.type);
    TestSerialize(val.get(), i2d_ASN1_TYPE, t.der);
  }
}

// Test that reading |value.ptr| from a FALSE |ASN1_TYPE| behaves correctly. The
// type historically supported this, so maintain the invariant in case external
// code relies on it.
TEST(ASN1Test, UnusedBooleanBits) {
  // OCTET_STRING { "a" }
  static const uint8_t kDER[] = {0x04, 0x01, 0x61};
  const uint8_t *ptr = kDER;
  bssl::UniquePtr<ASN1_TYPE> val(d2i_ASN1_TYPE(nullptr, &ptr, sizeof(kDER)));
  ASSERT_TRUE(val);
  EXPECT_EQ(V_ASN1_OCTET_STRING, val->type);
  EXPECT_TRUE(val->value.ptr);

  // Set |val| to a BOOLEAN containing FALSE.
  ASN1_TYPE_set(val.get(), V_ASN1_BOOLEAN, NULL);
  EXPECT_EQ(V_ASN1_BOOLEAN, val->type);
  EXPECT_FALSE(val->value.ptr);
}

TEST(ASN1Test, ASN1ObjectReuse) {
  // 1.2.840.113554.4.1.72585.2, an arbitrary unknown OID.
  static const uint8_t kOID[] = {0x2a, 0x86, 0x48, 0x86, 0xf7, 0x12,
                                 0x04, 0x01, 0x84, 0xb7, 0x09, 0x02};
  ASN1_OBJECT *obj = ASN1_OBJECT_create(NID_undef, kOID, sizeof(kOID),
                                        "short name", "long name");
  ASSERT_TRUE(obj);

  // OBJECT_IDENTIFIER { 1.3.101.112 }
  static const uint8_t kDER[] = {0x06, 0x03, 0x2b, 0x65, 0x70};
  const uint8_t *ptr = kDER;
  EXPECT_TRUE(d2i_ASN1_OBJECT(&obj, &ptr, sizeof(kDER)));
  EXPECT_EQ(NID_ED25519, OBJ_obj2nid(obj));
  ASN1_OBJECT_free(obj);

  // Repeat the test, this time overriding a static |ASN1_OBJECT|.
  obj = OBJ_nid2obj(NID_rsaEncryption);
  ptr = kDER;
  EXPECT_TRUE(d2i_ASN1_OBJECT(&obj, &ptr, sizeof(kDER)));
  EXPECT_EQ(NID_ED25519, OBJ_obj2nid(obj));
  ASN1_OBJECT_free(obj);
}

TEST(ASN1Test, BitString) {
  const size_t kNotWholeBytes = static_cast<size_t>(-1);
  const struct {
    std::vector<uint8_t> in;
    size_t num_bytes;
  } kValidInputs[] = {
      // Empty bit string
      {{0x03, 0x01, 0x00}, 0},
      // 0b1
      {{0x03, 0x02, 0x07, 0x80}, kNotWholeBytes},
      // 0b1010
      {{0x03, 0x02, 0x04, 0xa0}, kNotWholeBytes},
      // 0b1010101
      {{0x03, 0x02, 0x01, 0xaa}, kNotWholeBytes},
      // 0b10101010
      {{0x03, 0x02, 0x00, 0xaa}, 1},
      // Bits 0 and 63 are set
      {{0x03, 0x09, 0x00, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01}, 8},
      // 64 zero bits
      {{0x03, 0x09, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}, 8},
  };
  for (const auto &test : kValidInputs) {
    SCOPED_TRACE(Bytes(test.in));
    // The input should parse and round-trip correctly.
    const uint8_t *ptr = test.in.data();
    bssl::UniquePtr<ASN1_BIT_STRING> val(
        d2i_ASN1_BIT_STRING(nullptr, &ptr, test.in.size()));
    ASSERT_TRUE(val);
    TestSerialize(val.get(), i2d_ASN1_BIT_STRING, test.in);

    // Check the byte count.
    size_t num_bytes;
    if (test.num_bytes == kNotWholeBytes) {
      EXPECT_FALSE(ASN1_BIT_STRING_num_bytes(val.get(), &num_bytes));
    } else {
      ASSERT_TRUE(ASN1_BIT_STRING_num_bytes(val.get(), &num_bytes));
      EXPECT_EQ(num_bytes, test.num_bytes);
    }
  }

  const std::vector<uint8_t> kInvalidInputs[] = {
      // Wrong tag
      {0x04, 0x01, 0x00},
      // Missing leading byte
      {0x03, 0x00},
      // Leading byte too high
      {0x03, 0x02, 0x08, 0x00},
      {0x03, 0x02, 0xff, 0x00},
      // TODO(https://crbug.com/boringssl/354): Reject these inputs.
      // Empty bit strings must have a zero leading byte.
      // {0x03, 0x01, 0x01},
      // Unused bits must all be zero.
      // {0x03, 0x02, 0x06, 0xc1 /* 0b11000001 */},
  };
  for (const auto &test : kInvalidInputs) {
    SCOPED_TRACE(Bytes(test));
    const uint8_t *ptr = test.data();
    bssl::UniquePtr<ASN1_BIT_STRING> val(
        d2i_ASN1_BIT_STRING(nullptr, &ptr, test.size()));
    EXPECT_FALSE(val);
  }
}

TEST(ASN1Test, SetBit) {
  bssl::UniquePtr<ASN1_BIT_STRING> val(ASN1_BIT_STRING_new());
  ASSERT_TRUE(val);
  static const uint8_t kBitStringEmpty[] = {0x03, 0x01, 0x00};
  TestSerialize(val.get(), i2d_ASN1_BIT_STRING, kBitStringEmpty);
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 0));
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 100));

  // Set a few bits via |ASN1_BIT_STRING_set_bit|.
  ASSERT_TRUE(ASN1_BIT_STRING_set_bit(val.get(), 0, 1));
  ASSERT_TRUE(ASN1_BIT_STRING_set_bit(val.get(), 1, 1));
  ASSERT_TRUE(ASN1_BIT_STRING_set_bit(val.get(), 2, 0));
  ASSERT_TRUE(ASN1_BIT_STRING_set_bit(val.get(), 3, 1));
  static const uint8_t kBitString1101[] = {0x03, 0x02, 0x04, 0xd0};
  TestSerialize(val.get(), i2d_ASN1_BIT_STRING, kBitString1101);
  EXPECT_EQ(1, ASN1_BIT_STRING_get_bit(val.get(), 0));
  EXPECT_EQ(1, ASN1_BIT_STRING_get_bit(val.get(), 1));
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 2));
  EXPECT_EQ(1, ASN1_BIT_STRING_get_bit(val.get(), 3));
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 4));

  // Bits that were set may be cleared.
  ASSERT_TRUE(ASN1_BIT_STRING_set_bit(val.get(), 1, 0));
  static const uint8_t kBitString1001[] = {0x03, 0x02, 0x04, 0x90};
  TestSerialize(val.get(), i2d_ASN1_BIT_STRING, kBitString1001);
  EXPECT_EQ(1, ASN1_BIT_STRING_get_bit(val.get(), 0));
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 1));
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 2));
  EXPECT_EQ(1, ASN1_BIT_STRING_get_bit(val.get(), 3));
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 4));

  // Clearing trailing bits truncates the string.
  ASSERT_TRUE(ASN1_BIT_STRING_set_bit(val.get(), 3, 0));
  static const uint8_t kBitString1[] = {0x03, 0x02, 0x07, 0x80};
  TestSerialize(val.get(), i2d_ASN1_BIT_STRING, kBitString1);
  EXPECT_EQ(1, ASN1_BIT_STRING_get_bit(val.get(), 0));
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 1));
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 2));
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 3));
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 4));

  // Bits may be set beyond the end of the string.
  ASSERT_TRUE(ASN1_BIT_STRING_set_bit(val.get(), 63, 1));
  static const uint8_t kBitStringLong[] = {0x03, 0x09, 0x00, 0x80, 0x00, 0x00,
                                           0x00, 0x00, 0x00, 0x00, 0x01};
  TestSerialize(val.get(), i2d_ASN1_BIT_STRING, kBitStringLong);
  EXPECT_EQ(1, ASN1_BIT_STRING_get_bit(val.get(), 0));
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 62));
  EXPECT_EQ(1, ASN1_BIT_STRING_get_bit(val.get(), 63));
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 64));

  // The string can be truncated back down again.
  ASSERT_TRUE(ASN1_BIT_STRING_set_bit(val.get(), 63, 0));
  TestSerialize(val.get(), i2d_ASN1_BIT_STRING, kBitString1);
  EXPECT_EQ(1, ASN1_BIT_STRING_get_bit(val.get(), 0));
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 62));
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 63));
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 64));

  // |ASN1_BIT_STRING_set_bit| also truncates when starting from a parsed
  // string.
  const uint8_t *ptr = kBitStringLong;
  val.reset(d2i_ASN1_BIT_STRING(nullptr, &ptr, sizeof(kBitStringLong)));
  ASSERT_TRUE(val);
  TestSerialize(val.get(), i2d_ASN1_BIT_STRING, kBitStringLong);
  ASSERT_TRUE(ASN1_BIT_STRING_set_bit(val.get(), 63, 0));
  TestSerialize(val.get(), i2d_ASN1_BIT_STRING, kBitString1);
  EXPECT_EQ(1, ASN1_BIT_STRING_get_bit(val.get(), 0));
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 62));
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 63));
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 64));

  // A parsed bit string preserves trailing zero bits.
  static const uint8_t kBitString10010[] = {0x03, 0x02, 0x03, 0x90};
  ptr = kBitString10010;
  val.reset(d2i_ASN1_BIT_STRING(nullptr, &ptr, sizeof(kBitString10010)));
  ASSERT_TRUE(val);
  TestSerialize(val.get(), i2d_ASN1_BIT_STRING, kBitString10010);
  // But |ASN1_BIT_STRING_set_bit| will truncate it even if otherwise a no-op.
  ASSERT_TRUE(ASN1_BIT_STRING_set_bit(val.get(), 0, 1));
  TestSerialize(val.get(), i2d_ASN1_BIT_STRING, kBitString1001);
  EXPECT_EQ(1, ASN1_BIT_STRING_get_bit(val.get(), 0));
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 62));
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 63));
  EXPECT_EQ(0, ASN1_BIT_STRING_get_bit(val.get(), 64));

  // By default, a BIT STRING implicitly truncates trailing zeros.
  val.reset(ASN1_BIT_STRING_new());
  ASSERT_TRUE(val);
  static const uint8_t kZeros[64] = {0};
  ASSERT_TRUE(ASN1_STRING_set(val.get(), kZeros, sizeof(kZeros)));
  TestSerialize(val.get(), i2d_ASN1_BIT_STRING, kBitStringEmpty);
}

TEST(ASN1Test, StringToUTF8) {
  static const struct {
    std::vector<uint8_t> in;
    int type;
    const char *expected;
  } kTests[] = {
      // Non-minimal, two-byte UTF-8.
      {{0xc0, 0x81}, V_ASN1_UTF8STRING, nullptr},
      // Non-minimal, three-byte UTF-8.
      {{0xe0, 0x80, 0x81}, V_ASN1_UTF8STRING, nullptr},
      // Non-minimal, four-byte UTF-8.
      {{0xf0, 0x80, 0x80, 0x81}, V_ASN1_UTF8STRING, nullptr},
      // Truncated, four-byte UTF-8.
      {{0xf0, 0x80, 0x80}, V_ASN1_UTF8STRING, nullptr},
      // Low-surrogate value.
      {{0xed, 0xa0, 0x80}, V_ASN1_UTF8STRING, nullptr},
      // High-surrogate value.
      {{0xed, 0xb0, 0x81}, V_ASN1_UTF8STRING, nullptr},
      // Initial BOMs should be rejected from UCS-2 and UCS-4.
      {{0xfe, 0xff, 0, 88}, V_ASN1_BMPSTRING, nullptr},
      {{0, 0, 0xfe, 0xff, 0, 0, 0, 88}, V_ASN1_UNIVERSALSTRING, nullptr},
      // Otherwise, BOMs should pass through.
      {{0, 88, 0xfe, 0xff}, V_ASN1_BMPSTRING, "X\xef\xbb\xbf"},
      {{0, 0, 0, 88, 0, 0, 0xfe, 0xff}, V_ASN1_UNIVERSALSTRING,
       "X\xef\xbb\xbf"},
      // The maximum code-point should pass though.
      {{0, 16, 0xff, 0xfd}, V_ASN1_UNIVERSALSTRING, "\xf4\x8f\xbf\xbd"},
      // Values outside the Unicode space should not.
      {{0, 17, 0, 0}, V_ASN1_UNIVERSALSTRING, nullptr},
      // Non-characters should be rejected.
      {{0, 1, 0xff, 0xff}, V_ASN1_UNIVERSALSTRING, nullptr},
      {{0, 1, 0xff, 0xfe}, V_ASN1_UNIVERSALSTRING, nullptr},
      {{0, 0, 0xfd, 0xd5}, V_ASN1_UNIVERSALSTRING, nullptr},
      // BMPString is UCS-2, not UTF-16, so surrogate pairs are invalid.
      {{0xd8, 0, 0xdc, 1}, V_ASN1_BMPSTRING, nullptr},
  };

  for (const auto &test : kTests) {
    SCOPED_TRACE(Bytes(test.in));
    SCOPED_TRACE(test.type);
    bssl::UniquePtr<ASN1_STRING> s(ASN1_STRING_type_new(test.type));
    ASSERT_TRUE(s);
    ASSERT_TRUE(ASN1_STRING_set(s.get(), test.in.data(), test.in.size()));

    uint8_t *utf8;
    const int utf8_len = ASN1_STRING_to_UTF8(&utf8, s.get());
    EXPECT_EQ(utf8_len < 0, test.expected == nullptr);
    if (utf8_len >= 0) {
      if (test.expected != nullptr) {
        EXPECT_EQ(Bytes(test.expected), Bytes(utf8, utf8_len));
      }
      OPENSSL_free(utf8);
    } else {
      ERR_clear_error();
    }
  }
}

static std::string ASN1StringToStdString(const ASN1_STRING *str) {
  return std::string(ASN1_STRING_get0_data(str),
                     ASN1_STRING_get0_data(str) + ASN1_STRING_length(str));
}

TEST(ASN1Test, SetTime) {
  static const struct {
    time_t time;
    const char *generalized;
    const char *utc;
  } kTests[] = {
    {-631152001, "19491231235959Z", nullptr},
    {-631152000, "19500101000000Z", "500101000000Z"},
    {0, "19700101000000Z", "700101000000Z"},
    {981173106, "20010203040506Z", "010203040506Z"},
#if defined(OPENSSL_64_BIT)
    // TODO(https://crbug.com/boringssl/416): These cases overflow 32-bit
    // |time_t| and do not consistently work on 32-bit platforms. For now,
    // disable the tests on 32-bit. Re-enable them once the bug is fixed.
    {2524607999, "20491231235959Z", "491231235959Z"},
    {2524608000, "20500101000000Z", nullptr},
    // Test boundary conditions.
    {-62167219200, "00000101000000Z", nullptr},
    {-62167219201, nullptr, nullptr},
    {253402300799, "99991231235959Z", nullptr},
    {253402300800, nullptr, nullptr},
#endif
  };
  for (const auto &t : kTests) {
    SCOPED_TRACE(t.time);
#if defined(OPENSSL_WINDOWS)
    // Windows |time_t| functions can only handle 1970 through 3000. See
    // https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/gmtime-s-gmtime32-s-gmtime64-s?view=msvc-160
    if (t.time < 0 || int64_t{t.time} > 32535215999) {
      continue;
    }
#endif

    bssl::UniquePtr<ASN1_UTCTIME> utc(ASN1_UTCTIME_set(nullptr, t.time));
    if (t.utc) {
      ASSERT_TRUE(utc);
      EXPECT_EQ(V_ASN1_UTCTIME, ASN1_STRING_type(utc.get()));
      EXPECT_EQ(t.utc, ASN1StringToStdString(utc.get()));
    } else {
      EXPECT_FALSE(utc);
    }

    bssl::UniquePtr<ASN1_GENERALIZEDTIME> generalized(
        ASN1_GENERALIZEDTIME_set(nullptr, t.time));
    if (t.generalized) {
      ASSERT_TRUE(generalized);
      EXPECT_EQ(V_ASN1_GENERALIZEDTIME, ASN1_STRING_type(generalized.get()));
      EXPECT_EQ(t.generalized, ASN1StringToStdString(generalized.get()));
    } else {
      EXPECT_FALSE(generalized);
    }

    bssl::UniquePtr<ASN1_TIME> choice(ASN1_TIME_set(nullptr, t.time));
    if (t.generalized) {
      ASSERT_TRUE(choice);
      if (t.utc) {
        EXPECT_EQ(V_ASN1_UTCTIME, ASN1_STRING_type(choice.get()));
        EXPECT_EQ(t.utc, ASN1StringToStdString(choice.get()));
      } else {
        EXPECT_EQ(V_ASN1_GENERALIZEDTIME, ASN1_STRING_type(choice.get()));
        EXPECT_EQ(t.generalized, ASN1StringToStdString(choice.get()));
      }
    } else {
      EXPECT_FALSE(choice);
    }
  }
}

static std::vector<uint8_t> StringToVector(const std::string &str) {
  return std::vector<uint8_t>(str.begin(), str.end());
}

TEST(ASN1Test, StringPrintEx) {
  const struct {
    int type;
    std::vector<uint8_t> data;
    int str_flags;
    unsigned long flags;
    std::string expected;
  } kTests[] = {
      // A string like "hello" is never escaped or quoted.
      // |ASN1_STRFLGS_ESC_QUOTE| only introduces quotes when needed. Note
      // OpenSSL interprets T61String as Latin-1.
      {V_ASN1_T61STRING, StringToVector("hello"), 0, 0, "hello"},
      {V_ASN1_T61STRING, StringToVector("hello"), 0,
       ASN1_STRFLGS_ESC_2253 | ASN1_STRFLGS_ESC_CTRL | ASN1_STRFLGS_ESC_MSB,
       "hello"},
      {V_ASN1_T61STRING, StringToVector("hello"), 0,
       ASN1_STRFLGS_ESC_2253 | ASN1_STRFLGS_ESC_CTRL | ASN1_STRFLGS_ESC_MSB |
           ASN1_STRFLGS_ESC_QUOTE,
       "hello"},

      // By default, 8-bit characters are printed without escaping.
      {V_ASN1_T61STRING,
       {0, '\n', 0x80, 0xff, ',', '+', '"', '\\', '<', '>', ';'},
       0,
       0,
       std::string(1, '\0') + "\n\x80\xff,+\"\\<>;"},

      // Flags control different escapes. Note that any escape flag will cause
      // blackslashes to be escaped.
      {V_ASN1_T61STRING,
       {0, '\n', 0x80, 0xff, ',', '+', '"', '\\', '<', '>', ';'},
       0,
       ASN1_STRFLGS_ESC_2253,
       std::string(1, '\0') + "\n\x80\xff\\,\\+\\\"\\\\\\<\\>\\;"},
      {V_ASN1_T61STRING,
       {0, '\n', 0x80, 0xff, ',', '+', '"', '\\', '<', '>', ';'},
       0,
       ASN1_STRFLGS_ESC_CTRL,
       "\\00\\0A\x80\xff,+\"\\\\<>;"},
      {V_ASN1_T61STRING,
       {0, '\n', 0x80, 0xff, ',', '+', '"', '\\', '<', '>', ';'},
       0,
       ASN1_STRFLGS_ESC_MSB,
       std::string(1, '\0') + "\n\\80\\FF,+\"\\\\<>;"},
      {V_ASN1_T61STRING,
       {0, '\n', 0x80, 0xff, ',', '+', '"', '\\', '<', '>', ';'},
       0,
       ASN1_STRFLGS_ESC_2253 | ASN1_STRFLGS_ESC_CTRL | ASN1_STRFLGS_ESC_MSB,
       "\\00\\0A\\80\\FF\\,\\+\\\"\\\\\\<\\>\\;"},

      // When quoted, fewer characters need to be escaped in RFC 2253.
      {V_ASN1_T61STRING,
       {0, '\n', 0x80, 0xff, ',', '+', '"', '\\', '<', '>', ';'},
       0,
       ASN1_STRFLGS_ESC_2253 | ASN1_STRFLGS_ESC_CTRL | ASN1_STRFLGS_ESC_MSB |
           ASN1_STRFLGS_ESC_QUOTE,
       "\"\\00\\0A\\80\\FF,+\\\"\\\\<>;\""},

      // If no characters benefit from quotes, no quotes are added.
      {V_ASN1_T61STRING,
       {0, '\n', 0x80, 0xff, '"', '\\'},
       0,
       ASN1_STRFLGS_ESC_2253 | ASN1_STRFLGS_ESC_CTRL | ASN1_STRFLGS_ESC_MSB |
           ASN1_STRFLGS_ESC_QUOTE,
       "\\00\\0A\\80\\FF\\\"\\\\"},

      // RFC 2253 only escapes spaces at the start and end of a string.
      {V_ASN1_T61STRING, StringToVector("   "), 0, ASN1_STRFLGS_ESC_2253,
       "\\  \\ "},
      {V_ASN1_T61STRING, StringToVector("   "), 0,
       ASN1_STRFLGS_ESC_2253 | ASN1_STRFLGS_ESC_QUOTE, "\"   \""},

      // RFC 2253 only escapes # at the start of a string.
      {V_ASN1_T61STRING, StringToVector("###"), 0, ASN1_STRFLGS_ESC_2253,
       "\\###"},
      {V_ASN1_T61STRING, StringToVector("###"), 0,
       ASN1_STRFLGS_ESC_2253 | ASN1_STRFLGS_ESC_QUOTE, "\"###\""},

      // By default, strings are decoded and Unicode code points are
      // individually escaped.
      {V_ASN1_UTF8STRING, StringToVector("a\xc2\x80\xc4\x80\xf0\x90\x80\x80"),
       0, ASN1_STRFLGS_ESC_MSB, "a\\80\\U0100\\W00010000"},
      {V_ASN1_BMPSTRING,
       {0x00, 'a', 0x00, 0x80, 0x01, 0x00},
       0,
       ASN1_STRFLGS_ESC_MSB,
       "a\\80\\U0100"},
      {V_ASN1_UNIVERSALSTRING,
       {0x00, 0x00, 0x00, 'a',   //
        0x00, 0x00, 0x00, 0x80,  //
        0x00, 0x00, 0x01, 0x00,  //
        0x00, 0x01, 0x00, 0x00},
       0,
       ASN1_STRFLGS_ESC_MSB,
       "a\\80\\U0100\\W00010000"},

      // |ASN1_STRFLGS_UTF8_CONVERT| normalizes everything to UTF-8 and then
      // escapes individual bytes.
      {V_ASN1_IA5STRING, StringToVector("a\x80"), 0,
       ASN1_STRFLGS_ESC_MSB | ASN1_STRFLGS_UTF8_CONVERT, "a\\C2\\80"},
      {V_ASN1_T61STRING, StringToVector("a\x80"), 0,
       ASN1_STRFLGS_ESC_MSB | ASN1_STRFLGS_UTF8_CONVERT, "a\\C2\\80"},
      {V_ASN1_UTF8STRING, StringToVector("a\xc2\x80\xc4\x80\xf0\x90\x80\x80"),
       0, ASN1_STRFLGS_ESC_MSB | ASN1_STRFLGS_UTF8_CONVERT,
       "a\\C2\\80\\C4\\80\\F0\\90\\80\\80"},
      {V_ASN1_BMPSTRING,
       {0x00, 'a', 0x00, 0x80, 0x01, 0x00},
       0,
       ASN1_STRFLGS_ESC_MSB | ASN1_STRFLGS_UTF8_CONVERT,
       "a\\C2\\80\\C4\\80"},
      {V_ASN1_UNIVERSALSTRING,
       {0x00, 0x00, 0x00, 'a',   //
        0x00, 0x00, 0x00, 0x80,  //
        0x00, 0x00, 0x01, 0x00,  //
        0x00, 0x01, 0x00, 0x00},
       0,
       ASN1_STRFLGS_ESC_MSB | ASN1_STRFLGS_UTF8_CONVERT,
       "a\\C2\\80\\C4\\80\\F0\\90\\80\\80"},

      // The same as above, but without escaping the UTF-8 encoding.
      {V_ASN1_IA5STRING, StringToVector("a\x80"), 0, ASN1_STRFLGS_UTF8_CONVERT,
       "a\xc2\x80"},
      {V_ASN1_T61STRING, StringToVector("a\x80"), 0, ASN1_STRFLGS_UTF8_CONVERT,
       "a\xc2\x80"},
      {V_ASN1_UTF8STRING, StringToVector("a\xc2\x80\xc4\x80\xf0\x90\x80\x80"),
       0, ASN1_STRFLGS_UTF8_CONVERT, "a\xc2\x80\xc4\x80\xf0\x90\x80\x80"},
      {V_ASN1_BMPSTRING,
       {0x00, 'a', 0x00, 0x80, 0x01, 0x00},
       0,
       ASN1_STRFLGS_UTF8_CONVERT,
       "a\xc2\x80\xc4\x80"},
      {V_ASN1_UNIVERSALSTRING,
       {0x00, 0x00, 0x00, 'a',   //
        0x00, 0x00, 0x00, 0x80,  //
        0x00, 0x00, 0x01, 0x00,  //
        0x00, 0x01, 0x00, 0x00},
       0,
       ASN1_STRFLGS_UTF8_CONVERT,
       "a\xc2\x80\xc4\x80\xf0\x90\x80\x80"},

      // Types that cannot be decoded are, by default, treated as a byte string.
      {V_ASN1_OCTET_STRING, {0xff}, 0, 0, "\xff"},
      {-1, {0xff}, 0, 0, "\xff"},
      {100, {0xff}, 0, 0, "\xff"},

      // |ASN1_STRFLGS_UTF8_CONVERT| still converts these bytes to UTF-8.
      //
      // TODO(davidben): This seems like a bug. Although it's unclear because
      // the non-RFC-2253 options aren't especially sound. Can we just remove
      // them?
      {V_ASN1_OCTET_STRING, {0xff}, 0, ASN1_STRFLGS_UTF8_CONVERT, "\xc3\xbf"},
      {-1, {0xff}, 0, ASN1_STRFLGS_UTF8_CONVERT, "\xc3\xbf"},
      {100, {0xff}, 0, ASN1_STRFLGS_UTF8_CONVERT, "\xc3\xbf"},

      // |ASN1_STRFLGS_IGNORE_TYPE| causes the string type to be ignored, so it
      // is always treated as a byte string, even if it is not a valid encoding.
      {V_ASN1_UTF8STRING, {0xff}, 0, ASN1_STRFLGS_IGNORE_TYPE, "\xff"},
      {V_ASN1_BMPSTRING, {0xff}, 0, ASN1_STRFLGS_IGNORE_TYPE, "\xff"},
      {V_ASN1_UNIVERSALSTRING, {0xff}, 0, ASN1_STRFLGS_IGNORE_TYPE, "\xff"},

      // |ASN1_STRFLGS_SHOW_TYPE| prepends the type name.
      {V_ASN1_UTF8STRING, {'a'}, 0, ASN1_STRFLGS_SHOW_TYPE, "UTF8STRING:a"},
      {-1, {'a'}, 0, ASN1_STRFLGS_SHOW_TYPE, "(unknown):a"},
      {100, {'a'}, 0, ASN1_STRFLGS_SHOW_TYPE, "(unknown):a"},

      // |ASN1_STRFLGS_DUMP_ALL| and |ASN1_STRFLGS_DUMP_UNKNOWN| cause
      // non-string types to be printed in hex, though without the DER wrapper
      // by default.
      {V_ASN1_UTF8STRING, StringToVector("\xe2\x98\x83"), 0,
       ASN1_STRFLGS_DUMP_UNKNOWN, "\\U2603"},
      {V_ASN1_UTF8STRING, StringToVector("\xe2\x98\x83"), 0,
       ASN1_STRFLGS_DUMP_ALL, "#E29883"},
      {V_ASN1_OCTET_STRING, StringToVector("\xe2\x98\x83"), 0,
       ASN1_STRFLGS_DUMP_UNKNOWN, "#E29883"},
      {V_ASN1_OCTET_STRING, StringToVector("\xe2\x98\x83"), 0,
       ASN1_STRFLGS_DUMP_ALL, "#E29883"},

      // |ASN1_STRFLGS_DUMP_DER| includes the entire element.
      {V_ASN1_UTF8STRING, StringToVector("\xe2\x98\x83"), 0,
       ASN1_STRFLGS_DUMP_ALL | ASN1_STRFLGS_DUMP_DER, "#0C03E29883"},
      {V_ASN1_OCTET_STRING, StringToVector("\xe2\x98\x83"), 0,
       ASN1_STRFLGS_DUMP_ALL | ASN1_STRFLGS_DUMP_DER, "#0403E29883"},
      {V_ASN1_BIT_STRING,
       {0x80},
       ASN1_STRING_FLAG_BITS_LEFT | 4,
       ASN1_STRFLGS_DUMP_ALL | ASN1_STRFLGS_DUMP_DER,
       "#03020480"},
      // INTEGER { 1 }
      {V_ASN1_INTEGER,
       {0x01},
       0,
       ASN1_STRFLGS_DUMP_ALL | ASN1_STRFLGS_DUMP_DER,
       "#020101"},
      // INTEGER { -1 }
      {V_ASN1_NEG_INTEGER,
       {0x01},
       0,
       ASN1_STRFLGS_DUMP_ALL | ASN1_STRFLGS_DUMP_DER,
       "#0201FF"},
      // ENUMERATED { 1 }
      {V_ASN1_ENUMERATED,
       {0x01},
       0,
       ASN1_STRFLGS_DUMP_ALL | ASN1_STRFLGS_DUMP_DER,
       "#0A0101"},
      // ENUMERATED { -1 }
      {V_ASN1_NEG_ENUMERATED,
       {0x01},
       0,
       ASN1_STRFLGS_DUMP_ALL | ASN1_STRFLGS_DUMP_DER,
       "#0A01FF"},
  };
  for (const auto &t : kTests) {
    SCOPED_TRACE(t.type);
    SCOPED_TRACE(Bytes(t.data));
    SCOPED_TRACE(t.str_flags);
    SCOPED_TRACE(t.flags);

    bssl::UniquePtr<ASN1_STRING> str(ASN1_STRING_type_new(t.type));
    ASSERT_TRUE(ASN1_STRING_set(str.get(), t.data.data(), t.data.size()));
    str->flags = t.str_flags;

    // If the |BIO| is null, it should measure the size.
    int len = ASN1_STRING_print_ex(nullptr, str.get(), t.flags);
    EXPECT_EQ(len, static_cast<int>(t.expected.size()));

    // Measuring the size should also work for the |FILE| version
    len = ASN1_STRING_print_ex_fp(nullptr, str.get(), t.flags);
    EXPECT_EQ(len, static_cast<int>(t.expected.size()));

    // Actually print the string.
    bssl::UniquePtr<BIO> bio(BIO_new(BIO_s_mem()));
    ASSERT_TRUE(bio);
    len = ASN1_STRING_print_ex(bio.get(), str.get(), t.flags);
    EXPECT_EQ(len, static_cast<int>(t.expected.size()));

    const uint8_t *bio_contents;
    size_t bio_len;
    ASSERT_TRUE(BIO_mem_contents(bio.get(), &bio_contents, &bio_len));
    EXPECT_EQ(t.expected, std::string(bio_contents, bio_contents + bio_len));
  }

  const struct {
    int type;
    std::vector<uint8_t> data;
    int str_flags;
    unsigned long flags;
  } kUnprintableTests[] = {
      // When decoding strings, invalid codepoints are errors.
      {V_ASN1_UTF8STRING, {0xff}, 0, ASN1_STRFLGS_ESC_MSB},
      {V_ASN1_BMPSTRING, {0xff}, 0, ASN1_STRFLGS_ESC_MSB},
      {V_ASN1_BMPSTRING, {0xff}, 0, ASN1_STRFLGS_ESC_MSB},
      {V_ASN1_UNIVERSALSTRING, {0xff}, 0, ASN1_STRFLGS_ESC_MSB},
  };
  for (const auto &t : kUnprintableTests) {
    SCOPED_TRACE(t.type);
    SCOPED_TRACE(Bytes(t.data));
    SCOPED_TRACE(t.str_flags);
    SCOPED_TRACE(t.flags);

    bssl::UniquePtr<ASN1_STRING> str(ASN1_STRING_type_new(t.type));
    ASSERT_TRUE(ASN1_STRING_set(str.get(), t.data.data(), t.data.size()));
    str->flags = t.str_flags;

    // If the |BIO| is null, it should measure the size.
    int len = ASN1_STRING_print_ex(nullptr, str.get(), t.flags);
    EXPECT_EQ(len, -1);
    ERR_clear_error();

    // Measuring the size should also work for the |FILE| version
    len = ASN1_STRING_print_ex_fp(nullptr, str.get(), t.flags);
    EXPECT_EQ(len, -1);
    ERR_clear_error();

    // Actually print the string.
    bssl::UniquePtr<BIO> bio(BIO_new(BIO_s_mem()));
    ASSERT_TRUE(bio);
    len = ASN1_STRING_print_ex(bio.get(), str.get(), t.flags);
    EXPECT_EQ(len, -1);
    ERR_clear_error();
  }
}

TEST(ASN1Test, MBString) {
  const unsigned long kAll = B_ASN1_PRINTABLESTRING | B_ASN1_IA5STRING |
                             B_ASN1_T61STRING | B_ASN1_BMPSTRING |
                             B_ASN1_UNIVERSALSTRING | B_ASN1_UTF8STRING;

  const struct {
    int format;
    std::vector<uint8_t> in;
    unsigned long mask;
    int expected_type;
    std::vector<uint8_t> expected_data;
    int num_codepoints;
  } kTests[] = {
      // Given a choice of formats, we pick the smallest that fits.
      {MBSTRING_UTF8, {}, kAll, V_ASN1_PRINTABLESTRING, {}, 0},
      {MBSTRING_UTF8, {'a'}, kAll, V_ASN1_PRINTABLESTRING, {'a'}, 1},
      {MBSTRING_UTF8,
       {'a', 'A', '0', '\'', '(', ')', '+', ',', '-', '.', '/', ':', '=', '?'},
       kAll,
       V_ASN1_PRINTABLESTRING,
       {'a', 'A', '0', '\'', '(', ')', '+', ',', '-', '.', '/', ':', '=', '?'},
       14},
      {MBSTRING_UTF8, {'*'}, kAll, V_ASN1_IA5STRING, {'*'}, 1},
      {MBSTRING_UTF8, {'\n'}, kAll, V_ASN1_IA5STRING, {'\n'}, 1},
      {MBSTRING_UTF8,
       {0xc2, 0x80 /* U+0080 */},
       kAll,
       V_ASN1_T61STRING,
       {0x80},
       1},
      {MBSTRING_UTF8,
       {0xc4, 0x80 /* U+0100 */},
       kAll,
       V_ASN1_BMPSTRING,
       {0x01, 0x00},
       1},
      {MBSTRING_UTF8,
       {0xf0, 0x90, 0x80, 0x80 /* U+10000 */},
       kAll,
       V_ASN1_UNIVERSALSTRING,
       {0x00, 0x01, 0x00, 0x00},
       1},
      {MBSTRING_UTF8,
       {0xf0, 0x90, 0x80, 0x80 /* U+10000 */},
       kAll & ~B_ASN1_UNIVERSALSTRING,
       V_ASN1_UTF8STRING,
       {0xf0, 0x90, 0x80, 0x80},
       1},

      // NUL is not printable. It should also not terminate iteration.
      {MBSTRING_UTF8, {0}, kAll, V_ASN1_IA5STRING, {0}, 1},
      {MBSTRING_UTF8, {0, 'a'}, kAll, V_ASN1_IA5STRING, {0, 'a'}, 2},

      // When a particular format is specified, we use it.
      {MBSTRING_UTF8,
       {'a'},
       B_ASN1_PRINTABLESTRING,
       V_ASN1_PRINTABLESTRING,
       {'a'},
       1},
      {MBSTRING_UTF8, {'a'}, B_ASN1_IA5STRING, V_ASN1_IA5STRING, {'a'}, 1},
      {MBSTRING_UTF8, {'a'}, B_ASN1_T61STRING, V_ASN1_T61STRING, {'a'}, 1},
      {MBSTRING_UTF8, {'a'}, B_ASN1_UTF8STRING, V_ASN1_UTF8STRING, {'a'}, 1},
      {MBSTRING_UTF8,
       {'a'},
       B_ASN1_BMPSTRING,
       V_ASN1_BMPSTRING,
       {0x00, 'a'},
       1},
      {MBSTRING_UTF8,
       {'a'},
       B_ASN1_UNIVERSALSTRING,
       V_ASN1_UNIVERSALSTRING,
       {0x00, 0x00, 0x00, 'a'},
       1},

      // A long string with characters of many widths, to test sizes are
      // measured in code points.
      {MBSTRING_UTF8,
       {
           'a',                     //
           0xc2, 0x80,              // U+0080
           0xc4, 0x80,              // U+0100
           0xf0, 0x90, 0x80, 0x80,  // U+10000
       },
       B_ASN1_UNIVERSALSTRING,
       V_ASN1_UNIVERSALSTRING,
       {
           0x00, 0x00, 0x00, 'a',   //
           0x00, 0x00, 0x00, 0x80,  //
           0x00, 0x00, 0x01, 0x00,  //
           0x00, 0x01, 0x00, 0x00,  //
       },
       4},
  };
  for (const auto &t : kTests) {
    SCOPED_TRACE(t.format);
    SCOPED_TRACE(Bytes(t.in));
    SCOPED_TRACE(t.mask);

    // Passing in nullptr should do a dry run.
    EXPECT_EQ(t.expected_type,
              ASN1_mbstring_copy(nullptr, t.in.data(), t.in.size(), t.format,
                                 t.mask));

    // Test allocating a new object.
    ASN1_STRING *str = nullptr;
    EXPECT_EQ(
        t.expected_type,
        ASN1_mbstring_copy(&str, t.in.data(), t.in.size(), t.format, t.mask));
    ASSERT_TRUE(str);
    EXPECT_EQ(t.expected_type, ASN1_STRING_type(str));
    EXPECT_EQ(Bytes(t.expected_data),
              Bytes(ASN1_STRING_get0_data(str), ASN1_STRING_length(str)));

    // Test writing into an existing object.
    ASN1_STRING_free(str);
    str = ASN1_STRING_new();
    ASSERT_TRUE(str);
    ASN1_STRING *old_str = str;
    EXPECT_EQ(
        t.expected_type,
        ASN1_mbstring_copy(&str, t.in.data(), t.in.size(), t.format, t.mask));
    ASSERT_EQ(old_str, str);
    EXPECT_EQ(t.expected_type, ASN1_STRING_type(str));
    EXPECT_EQ(Bytes(t.expected_data),
              Bytes(ASN1_STRING_get0_data(str), ASN1_STRING_length(str)));
    ASN1_STRING_free(str);
    str = nullptr;

    // minsize and maxsize should be enforced, even in a dry run.
    EXPECT_EQ(t.expected_type,
              ASN1_mbstring_ncopy(nullptr, t.in.data(), t.in.size(), t.format,
                                  t.mask, /*minsize=*/t.num_codepoints,
                                  /*maxsize=*/t.num_codepoints));

    EXPECT_EQ(t.expected_type,
              ASN1_mbstring_ncopy(&str, t.in.data(), t.in.size(), t.format,
                                  t.mask, /*minsize=*/t.num_codepoints,
                                  /*maxsize=*/t.num_codepoints));
    ASSERT_TRUE(str);
    EXPECT_EQ(t.expected_type, ASN1_STRING_type(str));
    EXPECT_EQ(Bytes(t.expected_data),
              Bytes(ASN1_STRING_get0_data(str), ASN1_STRING_length(str)));
    ASN1_STRING_free(str);
    str = nullptr;

    EXPECT_EQ(-1, ASN1_mbstring_ncopy(
                      nullptr, t.in.data(), t.in.size(), t.format, t.mask,
                      /*minsize=*/t.num_codepoints + 1, /*maxsize=*/0));
    ERR_clear_error();
    EXPECT_EQ(-1, ASN1_mbstring_ncopy(
                      &str, t.in.data(), t.in.size(), t.format, t.mask,
                      /*minsize=*/t.num_codepoints + 1, /*maxsize=*/0));
    EXPECT_FALSE(str);
    ERR_clear_error();
    if (t.num_codepoints > 1) {
      EXPECT_EQ(-1, ASN1_mbstring_ncopy(
                        nullptr, t.in.data(), t.in.size(), t.format, t.mask,
                        /*minsize=*/0, /*maxsize=*/t.num_codepoints - 1));
      ERR_clear_error();
      EXPECT_EQ(-1, ASN1_mbstring_ncopy(
                        &str, t.in.data(), t.in.size(), t.format, t.mask,
                        /*minsize=*/0, /*maxsize=*/t.num_codepoints - 1));
      EXPECT_FALSE(str);
      ERR_clear_error();
    }
  }

  const struct {
    int format;
    std::vector<uint8_t> in;
    unsigned long mask;
  } kInvalidTests[] = {
      // Invalid encodings are rejected.
      {MBSTRING_UTF8, {0xff}, B_ASN1_UTF8STRING},
      {MBSTRING_BMP, {0xff}, B_ASN1_UTF8STRING},
      {MBSTRING_UNIV, {0xff}, B_ASN1_UTF8STRING},

      // Lone surrogates are not code points.
      {MBSTRING_UTF8, {0xed, 0xa0, 0x80}, B_ASN1_UTF8STRING},
      {MBSTRING_BMP, {0xd8, 0x00}, B_ASN1_UTF8STRING},
      {MBSTRING_UNIV, {0x00, 0x00, 0xd8, 0x00}, B_ASN1_UTF8STRING},

      // The input does not fit in the allowed output types.
      {MBSTRING_UTF8, {'\n'}, B_ASN1_PRINTABLESTRING},
      {MBSTRING_UTF8,
       {0xc2, 0x80 /* U+0080 */},
       B_ASN1_PRINTABLESTRING | B_ASN1_IA5STRING},
      {MBSTRING_UTF8,
       {0xc4, 0x80 /* U+0100 */},
       B_ASN1_PRINTABLESTRING | B_ASN1_IA5STRING | B_ASN1_T61STRING},
      {MBSTRING_UTF8,
       {0xf0, 0x90, 0x80, 0x80 /* U+10000 */},
       B_ASN1_PRINTABLESTRING | B_ASN1_IA5STRING | B_ASN1_T61STRING |
           B_ASN1_BMPSTRING},

      // Unrecognized bits are ignored.
      {MBSTRING_UTF8, {'\n'}, B_ASN1_PRINTABLESTRING | B_ASN1_SEQUENCE},
  };
  for (const auto &t : kInvalidTests) {
    SCOPED_TRACE(t.format);
    SCOPED_TRACE(Bytes(t.in));
    SCOPED_TRACE(t.mask);

    EXPECT_EQ(-1, ASN1_mbstring_copy(nullptr, t.in.data(), t.in.size(),
                                     t.format, t.mask));
    ERR_clear_error();

    ASN1_STRING *str = nullptr;
    EXPECT_EQ(-1, ASN1_mbstring_copy(&str, t.in.data(), t.in.size(),
                                     t.format, t.mask));
    ERR_clear_error();
    EXPECT_EQ(nullptr, str);
  }
}

TEST(ASN1Test, StringByNID) {
  // |ASN1_mbstring_*| tests above test most of the interactions with |inform|,
  // so all tests below use UTF-8.
  const struct {
    int nid;
    std::string in;
    int expected_type;
    std::string expected;
  } kTests[] = {
      // Although DirectoryString and PKCS9String allow many types of strings,
      // we prefer UTF8String.
      {NID_commonName, "abc", V_ASN1_UTF8STRING, "abc"},
      {NID_commonName, "\xe2\x98\x83", V_ASN1_UTF8STRING, "\xe2\x98\x83"},
      {NID_localityName, "abc", V_ASN1_UTF8STRING, "abc"},
      {NID_stateOrProvinceName, "abc", V_ASN1_UTF8STRING, "abc"},
      {NID_organizationName, "abc", V_ASN1_UTF8STRING, "abc"},
      {NID_organizationalUnitName, "abc", V_ASN1_UTF8STRING, "abc"},
      {NID_pkcs9_unstructuredName, "abc", V_ASN1_UTF8STRING, "abc"},
      {NID_pkcs9_challengePassword, "abc", V_ASN1_UTF8STRING, "abc"},
      {NID_pkcs9_unstructuredAddress, "abc", V_ASN1_UTF8STRING, "abc"},
      {NID_givenName, "abc", V_ASN1_UTF8STRING, "abc"},
      {NID_givenName, "abc", V_ASN1_UTF8STRING, "abc"},
      {NID_givenName, "abc", V_ASN1_UTF8STRING, "abc"},
      {NID_surname, "abc", V_ASN1_UTF8STRING, "abc"},
      {NID_initials, "abc", V_ASN1_UTF8STRING, "abc"},
      {NID_name, "abc", V_ASN1_UTF8STRING, "abc"},

      // Some attribute types use a particular string type.
      {NID_countryName, "US", V_ASN1_PRINTABLESTRING, "US"},
      {NID_pkcs9_emailAddress, "example@example.com", V_ASN1_IA5STRING,
       "example@example.com"},
      {NID_serialNumber, "1234", V_ASN1_PRINTABLESTRING, "1234"},
      {NID_friendlyName, "abc", V_ASN1_BMPSTRING,
       std::string({'\0', 'a', '\0', 'b', '\0', 'c'})},
      {NID_dnQualifier, "US", V_ASN1_PRINTABLESTRING, "US"},
      {NID_domainComponent, "com", V_ASN1_IA5STRING, "com"},
      {NID_ms_csp_name, "abc", V_ASN1_BMPSTRING,
       std::string({'\0', 'a', '\0', 'b', '\0', 'c'})},

      // Unknown NIDs default to UTF8String.
      {NID_rsaEncryption, "abc", V_ASN1_UTF8STRING, "abc"},
  };
  for (const auto &t : kTests) {
    SCOPED_TRACE(t.nid);
    SCOPED_TRACE(t.in);

    // Test allocating a new object.
    bssl::UniquePtr<ASN1_STRING> str(ASN1_STRING_set_by_NID(
        nullptr, reinterpret_cast<const uint8_t *>(t.in.data()), t.in.size(),
        MBSTRING_UTF8, t.nid));
    ASSERT_TRUE(str);
    EXPECT_EQ(t.expected_type, ASN1_STRING_type(str.get()));
    EXPECT_EQ(Bytes(t.expected), Bytes(ASN1_STRING_get0_data(str.get()),
                                       ASN1_STRING_length(str.get())));

    // Test writing into an existing object.
    str.reset(ASN1_STRING_new());
    ASSERT_TRUE(str);
    ASN1_STRING *old_str = str.get();
    ASSERT_TRUE(ASN1_STRING_set_by_NID(
        &old_str, reinterpret_cast<const uint8_t *>(t.in.data()), t.in.size(),
        MBSTRING_UTF8, t.nid));
    ASSERT_EQ(old_str, str.get());
    EXPECT_EQ(t.expected_type, ASN1_STRING_type(str.get()));
    EXPECT_EQ(Bytes(t.expected), Bytes(ASN1_STRING_get0_data(str.get()),
                                       ASN1_STRING_length(str.get())));
  }

  const struct {
    int nid;
    std::string in;
  } kInvalidTests[] = {
      // DirectoryString forbids empty inputs.
      {NID_commonName, ""},
      {NID_localityName, ""},
      {NID_stateOrProvinceName, ""},
      {NID_organizationName, ""},
      {NID_organizationalUnitName, ""},
      {NID_pkcs9_unstructuredName, ""},
      {NID_pkcs9_challengePassword, ""},
      {NID_pkcs9_unstructuredAddress, ""},
      {NID_givenName, ""},
      {NID_givenName, ""},
      {NID_givenName, ""},
      {NID_surname, ""},
      {NID_initials, ""},
      {NID_name, ""},

      // Test upper bounds from RFC 5280.
      {NID_name, std::string(32769, 'a')},
      {NID_commonName, std::string(65, 'a')},
      {NID_localityName, std::string(129, 'a')},
      {NID_stateOrProvinceName, std::string(129, 'a')},
      {NID_organizationName, std::string(65, 'a')},
      {NID_organizationalUnitName, std::string(65, 'a')},
      {NID_pkcs9_emailAddress, std::string(256, 'a')},
      {NID_serialNumber, std::string(65, 'a')},

      // X520countryName must be exactly two characters.
      {NID_countryName, "A"},
      {NID_countryName, "AAA"},

      // Some string types cannot represent all codepoints.
      {NID_countryName, "\xe2\x98\x83"},
      {NID_pkcs9_emailAddress, "\xe2\x98\x83"},
      {NID_serialNumber, "\xe2\x98\x83"},
      {NID_dnQualifier, "\xe2\x98\x83"},
      {NID_domainComponent, "\xe2\x98\x83"},
  };
  for (const auto &t : kInvalidTests) {
    SCOPED_TRACE(t.nid);
    SCOPED_TRACE(t.in);
    bssl::UniquePtr<ASN1_STRING> str(ASN1_STRING_set_by_NID(
        nullptr, reinterpret_cast<const uint8_t *>(t.in.data()), t.in.size(),
        MBSTRING_UTF8, t.nid));
    EXPECT_FALSE(str);
    ERR_clear_error();
  }
}

TEST(ASN1Test, StringByCustomNID) {
  // This test affects library-global state. We rely on nothing else in the test
  // suite using these OIDs.
  int nid1 = OBJ_create("1.2.840.113554.4.1.72585.1000", "custom OID 1",
                        "custom OID 1");
  ASSERT_NE(NID_undef, nid1);
  int nid2 = OBJ_create("1.2.840.113554.4.1.72585.1001", "custom OID 2",
                        "custom OID 2");
  ASSERT_NE(NID_undef, nid2);

  // Values registered in the string table should be picked up.
  ASSERT_TRUE(ASN1_STRING_TABLE_add(nid1, 5, 10, V_ASN1_PRINTABLESTRING,
                                    STABLE_NO_MASK));
  bssl::UniquePtr<ASN1_STRING> str(ASN1_STRING_set_by_NID(
      nullptr, reinterpret_cast<const uint8_t *>("12345"), 5, MBSTRING_UTF8,
      nid1));
  ASSERT_TRUE(str);
  EXPECT_EQ(V_ASN1_PRINTABLESTRING, ASN1_STRING_type(str.get()));
  EXPECT_EQ(Bytes("12345"), Bytes(ASN1_STRING_get0_data(str.get()),
                                  ASN1_STRING_length(str.get())));

  // Minimum and maximum lengths are enforced.
  str.reset(ASN1_STRING_set_by_NID(
      nullptr, reinterpret_cast<const uint8_t *>("1234"), 4, MBSTRING_UTF8,
      nid1));
  EXPECT_FALSE(str);
  ERR_clear_error();
  str.reset(ASN1_STRING_set_by_NID(
      nullptr, reinterpret_cast<const uint8_t *>("12345678901"), 11,
      MBSTRING_UTF8, nid1));
  EXPECT_FALSE(str);
  ERR_clear_error();

  // Without |STABLE_NO_MASK|, we always pick UTF8String. -1 means there is no
  // length limit.
  ASSERT_TRUE(ASN1_STRING_TABLE_add(nid2, -1, -1, DIRSTRING_TYPE, 0));
  str.reset(ASN1_STRING_set_by_NID(nullptr,
                                   reinterpret_cast<const uint8_t *>("12345"),
                                   5, MBSTRING_UTF8, nid2));
  ASSERT_TRUE(str);
  EXPECT_EQ(V_ASN1_UTF8STRING, ASN1_STRING_type(str.get()));
  EXPECT_EQ(Bytes("12345"), Bytes(ASN1_STRING_get0_data(str.get()),
                                  ASN1_STRING_length(str.get())));
}

// Test that multi-string types correctly encode negative ENUMERATED.
// Multi-string types cannot contain INTEGER, so we only test ENUMERATED.
TEST(ASN1Test, NegativeEnumeratedMultistring) {
  static const uint8_t kMinusOne[] = {0x0a, 0x01, 0xff};  // ENUMERATED { -1 }
  // |ASN1_PRINTABLE| is a multi-string type that allows ENUMERATED.
  const uint8_t *p = kMinusOne;
  bssl::UniquePtr<ASN1_STRING> str(
      d2i_ASN1_PRINTABLE(nullptr, &p, sizeof(kMinusOne)));
  ASSERT_TRUE(str);
  TestSerialize(str.get(), i2d_ASN1_PRINTABLE, kMinusOne);
}

TEST(ASN1Test, PrintableType) {
  const struct {
    std::vector<uint8_t> in;
    int result;
  } kTests[] = {
      {{}, V_ASN1_PRINTABLESTRING},
      {{'a', 'A', '0', '\'', '(', ')', '+', ',', '-', '.', '/', ':', '=', '?'},
       V_ASN1_PRINTABLESTRING},
      {{'*'}, V_ASN1_IA5STRING},
      {{'\0'}, V_ASN1_IA5STRING},
      {{'\0', 'a'}, V_ASN1_IA5STRING},
      {{0, 1, 2, 3, 125, 126, 127}, V_ASN1_IA5STRING},
      {{0, 1, 2, 3, 125, 126, 127, 128}, V_ASN1_T61STRING},
      {{128, 0, 1, 2, 3, 125, 126, 127}, V_ASN1_T61STRING},
  };
  for (const auto &t : kTests) {
    SCOPED_TRACE(Bytes(t.in));
    EXPECT_EQ(t.result, ASN1_PRINTABLE_type(t.in.data(), t.in.size()));
  }
}

// Encoding a CHOICE type with an invalid selector should fail.
TEST(ASN1Test, InvalidChoice) {
  bssl::UniquePtr<GENERAL_NAME> name(GENERAL_NAME_new());
  ASSERT_TRUE(name);
  // CHOICE types are initialized with an invalid selector.
  EXPECT_EQ(-1, name->type);
  // |name| should fail to encode.
  EXPECT_EQ(-1, i2d_GENERAL_NAME(name.get(), nullptr));

  // The error should be propagated through types containing |name|.
  bssl::UniquePtr<GENERAL_NAMES> names(GENERAL_NAMES_new());
  ASSERT_TRUE(names);
  EXPECT_TRUE(bssl::PushToStack(names.get(), std::move(name)));
  EXPECT_EQ(-1, i2d_GENERAL_NAMES(names.get(), nullptr));
}

// Encoding NID-only |ASN1_OBJECT|s should fail.
TEST(ASN1Test, InvalidObject) {
  EXPECT_EQ(-1, i2d_ASN1_OBJECT(OBJ_nid2obj(NID_kx_ecdhe), nullptr));

  bssl::UniquePtr<X509_ALGOR> alg(X509_ALGOR_new());
  ASSERT_TRUE(alg);
  ASSERT_TRUE(X509_ALGOR_set0(alg.get(), OBJ_nid2obj(NID_kx_ecdhe),
                              V_ASN1_UNDEF, nullptr));
  EXPECT_EQ(-1, i2d_X509_ALGOR(alg.get(), nullptr));
}

// Encoding invalid |ASN1_TYPE|s should fail. |ASN1_TYPE|s are
// default-initialized to an invalid type.
TEST(ASN1Test, InvalidASN1Type) {
  bssl::UniquePtr<ASN1_TYPE> obj(ASN1_TYPE_new());
  ASSERT_TRUE(obj);
  EXPECT_EQ(-1, obj->type);
  EXPECT_EQ(-1, i2d_ASN1_TYPE(obj.get(), nullptr));
}

// Encoding invalid MSTRING types should fail. An MSTRING is a CHOICE of
// string-like types. They are initialized to an invalid type.
TEST(ASN1Test, InvalidMSTRING) {
  bssl::UniquePtr<ASN1_STRING> obj(ASN1_TIME_new());
  ASSERT_TRUE(obj);
  EXPECT_EQ(-1, obj->type);
  EXPECT_EQ(-1, i2d_ASN1_TIME(obj.get(), nullptr));

  obj.reset(DIRECTORYSTRING_new());
  ASSERT_TRUE(obj);
  EXPECT_EQ(-1, obj->type);
  EXPECT_EQ(-1, i2d_DIRECTORYSTRING(obj.get(), nullptr));
}

TEST(ASN1Test, StringTableSorted) {
  const ASN1_STRING_TABLE *table;
  size_t table_len;
  asn1_get_string_table_for_testing(&table, &table_len);
  for (size_t i = 1; i < table_len; i++) {
    EXPECT_LT(table[i-1].nid, table[i].nid);
  }
}

// The ASN.1 macros do not work on Windows shared library builds, where usage of
// |OPENSSL_EXPORT| is a bit stricter.
#if !defined(OPENSSL_WINDOWS) || !defined(BORINGSSL_SHARED_LIBRARY)

typedef struct asn1_linked_list_st {
  struct asn1_linked_list_st *next;
} ASN1_LINKED_LIST;

DECLARE_ASN1_ITEM(ASN1_LINKED_LIST)
DECLARE_ASN1_FUNCTIONS(ASN1_LINKED_LIST)

ASN1_SEQUENCE(ASN1_LINKED_LIST) = {
    ASN1_OPT(ASN1_LINKED_LIST, next, ASN1_LINKED_LIST),
} ASN1_SEQUENCE_END(ASN1_LINKED_LIST)

IMPLEMENT_ASN1_FUNCTIONS(ASN1_LINKED_LIST)

static bool MakeLinkedList(bssl::UniquePtr<uint8_t> *out, size_t *out_len,
                           size_t count) {
  bssl::ScopedCBB cbb;
  std::vector<CBB> cbbs(count);
  if (!CBB_init(cbb.get(), 2 * count) ||
      !CBB_add_asn1(cbb.get(), &cbbs[0], CBS_ASN1_SEQUENCE)) {
    return false;
  }
  for (size_t i = 1; i < count; i++) {
    if (!CBB_add_asn1(&cbbs[i - 1], &cbbs[i], CBS_ASN1_SEQUENCE)) {
      return false;
    }
  }
  uint8_t *ptr;
  if (!CBB_finish(cbb.get(), &ptr, out_len)) {
    return false;
  }
  out->reset(ptr);
  return true;
}

TEST(ASN1Test, Recursive) {
  bssl::UniquePtr<uint8_t> data;
  size_t len;

  // Sanity-check that MakeLinkedList can be parsed.
  ASSERT_TRUE(MakeLinkedList(&data, &len, 5));
  const uint8_t *ptr = data.get();
  ASN1_LINKED_LIST *list = d2i_ASN1_LINKED_LIST(nullptr, &ptr, len);
  EXPECT_TRUE(list);
  ASN1_LINKED_LIST_free(list);

  // Excessively deep structures are rejected.
  ASSERT_TRUE(MakeLinkedList(&data, &len, 100));
  ptr = data.get();
  list = d2i_ASN1_LINKED_LIST(nullptr, &ptr, len);
  EXPECT_FALSE(list);
  // Note checking the error queue here does not work. The error "stack trace"
  // is too deep, so the |ASN1_R_NESTED_TOO_DEEP| entry drops off the queue.
  ASN1_LINKED_LIST_free(list);
}

struct IMPLICIT_CHOICE {
  ASN1_STRING *string;
};

DECLARE_ASN1_FUNCTIONS(IMPLICIT_CHOICE)

ASN1_SEQUENCE(IMPLICIT_CHOICE) = {
    ASN1_IMP(IMPLICIT_CHOICE, string, DIRECTORYSTRING, 0),
} ASN1_SEQUENCE_END(IMPLICIT_CHOICE)

IMPLEMENT_ASN1_FUNCTIONS(IMPLICIT_CHOICE)

// Test that the ASN.1 templates reject types with implicitly-tagged CHOICE
// types.
TEST(ASN1Test, ImplicitChoice) {
  // Serializing a type with an implicitly tagged CHOICE should fail.
  std::unique_ptr<IMPLICIT_CHOICE, decltype(&IMPLICIT_CHOICE_free)> obj(
      IMPLICIT_CHOICE_new(), IMPLICIT_CHOICE_free);
  EXPECT_EQ(-1, i2d_IMPLICIT_CHOICE(obj.get(), nullptr));

  // An implicitly-tagged CHOICE is an error. Depending on the implementation,
  // it may be misinterpreted as without the tag, or as clobbering the CHOICE
  // tag. Test both inputs and ensure they fail.

  // SEQUENCE { UTF8String {} }
  static const uint8_t kInput1[] = {0x30, 0x02, 0x0c, 0x00};
  const uint8_t *ptr = kInput1;
  EXPECT_EQ(nullptr, d2i_IMPLICIT_CHOICE(nullptr, &ptr, sizeof(kInput1)));

  // SEQUENCE { [0 PRIMITIVE] {} }
  static const uint8_t kInput2[] = {0x30, 0x02, 0x80, 0x00};
  ptr = kInput2;
  EXPECT_EQ(nullptr, d2i_IMPLICIT_CHOICE(nullptr, &ptr, sizeof(kInput2)));
}

struct REQUIRED_FIELD {
  ASN1_INTEGER *value;
  ASN1_INTEGER *value_imp;
  ASN1_INTEGER *value_exp;
  STACK_OF(ASN1_INTEGER) *seq;
  STACK_OF(ASN1_INTEGER) *seq_imp;
  STACK_OF(ASN1_INTEGER) *seq_exp;
};

DECLARE_ASN1_FUNCTIONS(REQUIRED_FIELD)
ASN1_SEQUENCE(REQUIRED_FIELD) = {
    ASN1_SIMPLE(REQUIRED_FIELD, value, ASN1_INTEGER),
    ASN1_IMP(REQUIRED_FIELD, value_imp, ASN1_INTEGER, 0),
    ASN1_EXP(REQUIRED_FIELD, value_exp, ASN1_INTEGER, 1),
    ASN1_SEQUENCE_OF(REQUIRED_FIELD, seq, ASN1_INTEGER),
    ASN1_IMP_SEQUENCE_OF(REQUIRED_FIELD, seq_imp, ASN1_INTEGER, 2),
    ASN1_EXP_SEQUENCE_OF(REQUIRED_FIELD, seq_exp, ASN1_INTEGER, 3),
} ASN1_SEQUENCE_END(REQUIRED_FIELD)
IMPLEMENT_ASN1_FUNCTIONS(REQUIRED_FIELD)

// Test that structures with missing required fields cannot be serialized. Test
// the full combination of tagging and SEQUENCE OF.
TEST(ASN1Test, MissingRequiredField) {
  EXPECT_EQ(-1, i2d_REQUIRED_FIELD(nullptr, nullptr));

  std::unique_ptr<REQUIRED_FIELD, decltype(&REQUIRED_FIELD_free)> obj(
      nullptr, REQUIRED_FIELD_free);
  for (auto field : {&REQUIRED_FIELD::value, &REQUIRED_FIELD::value_imp,
                     &REQUIRED_FIELD::value_exp}) {
    obj.reset(REQUIRED_FIELD_new());
    ASSERT_TRUE(obj);
    ASN1_INTEGER_free((*obj).*field);
    (*obj).*field = nullptr;
    EXPECT_EQ(-1, i2d_REQUIRED_FIELD(obj.get(), nullptr));
  }

  for (auto field : {&REQUIRED_FIELD::seq, &REQUIRED_FIELD::seq_imp,
                     &REQUIRED_FIELD::seq_exp}) {
    obj.reset(REQUIRED_FIELD_new());
    ASSERT_TRUE(obj);
    sk_ASN1_INTEGER_pop_free((*obj).*field, ASN1_INTEGER_free);
    (*obj).*field = nullptr;
    EXPECT_EQ(-1, i2d_REQUIRED_FIELD(obj.get(), nullptr));
  }
}

#endif  // !WINDOWS || !SHARED_LIBRARY