Exemple #1
0
int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, size_t key_len,
                 const EVP_MD *md, ENGINE *impl) {
  if (md == NULL) {
    md = ctx->md;
  }

  // If either |key| is non-NULL or |md| has changed, initialize with a new key
  // rather than rewinding the previous one.
  //
  // TODO(davidben,eroman): Passing the previous |md| with a NULL |key| is
  // ambiguous between using the empty key and reusing the previous key. There
  // exist callers which intend the latter, but the former is an awkward edge
  // case. Fix to API to avoid this.
  if (md != ctx->md || key != NULL) {
    uint8_t pad[EVP_MAX_MD_BLOCK_SIZE];
    uint8_t key_block[EVP_MAX_MD_BLOCK_SIZE];
    unsigned key_block_len;

    size_t block_size = EVP_MD_block_size(md);
    assert(block_size <= sizeof(key_block));
    if (block_size < key_len) {
      // Long keys are hashed.
      if (!EVP_DigestInit_ex(&ctx->md_ctx, md, impl) ||
          !EVP_DigestUpdate(&ctx->md_ctx, key, key_len) ||
          !EVP_DigestFinal_ex(&ctx->md_ctx, key_block, &key_block_len)) {
        return 0;
      }
    } else {
      assert(key_len <= sizeof(key_block));
      OPENSSL_memcpy(key_block, key, key_len);
      key_block_len = (unsigned)key_len;
    }
    // Keys are then padded with zeros.
    if (key_block_len != EVP_MAX_MD_BLOCK_SIZE) {
      OPENSSL_memset(&key_block[key_block_len], 0, sizeof(key_block) - key_block_len);
    }

    for (size_t i = 0; i < EVP_MAX_MD_BLOCK_SIZE; i++) {
      pad[i] = 0x36 ^ key_block[i];
    }
    if (!EVP_DigestInit_ex(&ctx->i_ctx, md, impl) ||
        !EVP_DigestUpdate(&ctx->i_ctx, pad, EVP_MD_block_size(md))) {
      return 0;
    }

    for (size_t i = 0; i < EVP_MAX_MD_BLOCK_SIZE; i++) {
      pad[i] = 0x5c ^ key_block[i];
    }
    if (!EVP_DigestInit_ex(&ctx->o_ctx, md, impl) ||
        !EVP_DigestUpdate(&ctx->o_ctx, pad, EVP_MD_block_size(md))) {
      return 0;
    }

    ctx->md = md;
  }

  if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->i_ctx)) {
    return 0;
  }

  return 1;
}
Exemple #2
0
void EVP_tls_cbc_copy_mac(uint8_t *out, size_t md_size, const uint8_t *in,
                          size_t in_len, size_t orig_len) {
  uint8_t rotated_mac1[EVP_MAX_MD_SIZE], rotated_mac2[EVP_MAX_MD_SIZE];
  uint8_t *rotated_mac = rotated_mac1;
  uint8_t *rotated_mac_tmp = rotated_mac2;

  // mac_end is the index of |in| just after the end of the MAC.
  size_t mac_end = in_len;
  size_t mac_start = mac_end - md_size;

  assert(orig_len >= in_len);
  assert(in_len >= md_size);
  assert(md_size <= EVP_MAX_MD_SIZE);

  // scan_start contains the number of bytes that we can ignore because
  // the MAC's position can only vary by 255 bytes.
  size_t scan_start = 0;
  // This information is public so it's safe to branch based on it.
  if (orig_len > md_size + 255 + 1) {
    scan_start = orig_len - (md_size + 255 + 1);
  }

  size_t rotate_offset = 0;
  uint8_t mac_started = 0;
  OPENSSL_memset(rotated_mac, 0, md_size);
  for (size_t i = scan_start, j = 0; i < orig_len; i++, j++) {
    if (j >= md_size) {
      j -= md_size;
    }
    crypto_word_t is_mac_start = constant_time_eq_w(i, mac_start);
    mac_started |= is_mac_start;
    uint8_t mac_ended = constant_time_ge_8(i, mac_end);
    rotated_mac[j] |= in[i] & mac_started & ~mac_ended;
    // Save the offset that |mac_start| is mapped to.
    rotate_offset |= j & is_mac_start;
  }

  // Now rotate the MAC. We rotate in log(md_size) steps, one for each bit
  // position.
  for (size_t offset = 1; offset < md_size; offset <<= 1, rotate_offset >>= 1) {
    // Rotate by |offset| iff the corresponding bit is set in
    // |rotate_offset|, placing the result in |rotated_mac_tmp|.
    const uint8_t skip_rotate = (rotate_offset & 1) - 1;
    for (size_t i = 0, j = offset; i < md_size; i++, j++) {
      if (j >= md_size) {
        j -= md_size;
      }
      rotated_mac_tmp[i] =
          constant_time_select_8(skip_rotate, rotated_mac[i], rotated_mac[j]);
    }

    // Swap pointers so |rotated_mac| contains the (possibly) rotated value.
    // Note the number of iterations and thus the identity of these pointers is
    // public information.
    uint8_t *tmp = rotated_mac;
    rotated_mac = rotated_mac_tmp;
    rotated_mac_tmp = tmp;
  }

  OPENSSL_memcpy(out, rotated_mac, md_size);
}
Exemple #3
0
static int aead_aes_gcm_seal_scatter(const EVP_AEAD_CTX *ctx, uint8_t *out,
                                     uint8_t *out_tag, size_t *out_tag_len,
                                     size_t max_out_tag_len,
                                     const uint8_t *nonce, size_t nonce_len,
                                     const uint8_t *in, size_t in_len,
                                     const uint8_t *extra_in,
                                     size_t extra_in_len,
                                     const uint8_t *ad, size_t ad_len) {
  struct aead_aes_gcm_ctx *gcm_ctx = (struct aead_aes_gcm_ctx *) &ctx->state;

  if (extra_in_len + ctx->tag_len < ctx->tag_len) {
    OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE);
    return 0;
  }
  if (max_out_tag_len < extra_in_len + ctx->tag_len) {
    OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BUFFER_TOO_SMALL);
    return 0;
  }
  if (nonce_len == 0) {
    OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_INVALID_NONCE_SIZE);
    return 0;
  }

  const AES_KEY *key = &gcm_ctx->ks.ks;

  GCM128_CONTEXT gcm;
  OPENSSL_memset(&gcm, 0, sizeof(gcm));
  OPENSSL_memcpy(&gcm.gcm_key, &gcm_ctx->gcm_key, sizeof(gcm.gcm_key));
  CRYPTO_gcm128_setiv(&gcm, key, nonce, nonce_len);

  if (ad_len > 0 && !CRYPTO_gcm128_aad(&gcm, ad, ad_len)) {
    return 0;
  }

  if (gcm_ctx->ctr) {
    if (!CRYPTO_gcm128_encrypt_ctr32(&gcm, key, in, out, in_len,
                                     gcm_ctx->ctr)) {
      return 0;
    }
  } else {
    if (!CRYPTO_gcm128_encrypt(&gcm, key, in, out, in_len)) {
      return 0;
    }
  }

  if (extra_in_len) {
    if (gcm_ctx->ctr) {
      if (!CRYPTO_gcm128_encrypt_ctr32(&gcm, key, extra_in, out_tag,
                                       extra_in_len, gcm_ctx->ctr)) {
        return 0;
      }
    } else {
      if (!CRYPTO_gcm128_encrypt(&gcm, key, extra_in, out_tag, extra_in_len)) {
        return 0;
      }
    }
  }

  CRYPTO_gcm128_tag(&gcm, out_tag + extra_in_len, ctx->tag_len);
  *out_tag_len = ctx->tag_len + extra_in_len;

  return 1;
}
int BORINGSSL_self_test(void) {
  static const uint8_t kAESKey[16] = "BoringCrypto Key";
  static const uint8_t kAESIV[16] = {0};
  static const uint8_t kPlaintext[64] =
      "BoringCryptoModule FIPS KAT Encryption and Decryption Plaintext!";
  static const uint8_t kAESCBCCiphertext[64] = {
      0x87, 0x2d, 0x98, 0xc2, 0xcc, 0x31, 0x5b, 0x41, 0xe0, 0xfa, 0x7b,
      0x0a, 0x71, 0xc0, 0x42, 0xbf, 0x4f, 0x61, 0xd0, 0x0d, 0x58, 0x8c,
      0xf7, 0x05, 0xfb, 0x94, 0x89, 0xd3, 0xbc, 0xaa, 0x1a, 0x50, 0x45,
      0x1f, 0xc3, 0x8c, 0xb8, 0x98, 0x86, 0xa3, 0xe3, 0x6c, 0xfc, 0xad,
      0x3a, 0xb5, 0x59, 0x27, 0x7d, 0x21, 0x07, 0xca, 0x4c, 0x1d, 0x55,
      0x34, 0xdd, 0x5a, 0x2d, 0xc4, 0xb4, 0xf5, 0xa8,
#if !defined(BORINGSSL_FIPS_BREAK_AES_CBC)
      0x35
#else
      0x00
#endif
  };
  static const uint8_t kAESGCMCiphertext[80] = {
      0x4a, 0xd8, 0xe7, 0x7d, 0x78, 0xd7, 0x7d, 0x5e, 0xb2, 0x11, 0xb6, 0xc9,
      0xa4, 0xbc, 0xb2, 0xae, 0xbe, 0x93, 0xd1, 0xb7, 0xfe, 0x65, 0xc1, 0x82,
      0x2a, 0xb6, 0x71, 0x5f, 0x1a, 0x7c, 0xe0, 0x1b, 0x2b, 0xe2, 0x53, 0xfa,
      0xa0, 0x47, 0xfa, 0xd7, 0x8f, 0xb1, 0x4a, 0xc4, 0xdc, 0x89, 0xf9, 0xb4,
      0x14, 0x4d, 0xde, 0x95, 0xea, 0x29, 0x69, 0x76, 0x81, 0xa3, 0x5c, 0x33,
      0xd8, 0x37, 0xd8, 0xfa, 0x47, 0x19, 0x46, 0x2f, 0xf1, 0x90, 0xb7, 0x61,
      0x8f, 0x6f, 0xdd, 0x31, 0x3f, 0x6a, 0x64,
#if !defined(BORINGSSL_FIPS_BREAK_AES_GCM)
      0x0d
#else
      0x00
#endif
  };
  static const DES_cblock kDESKey1 = {"BCMDESK1"};
  static const DES_cblock kDESKey2 = {"BCMDESK2"};
  static const DES_cblock kDESKey3 = {"BCMDESK3"};
  static const DES_cblock kDESIV = {"BCMDESIV"};
  static const uint8_t kDESCiphertext[64] = {
      0xa4, 0x30, 0x7a, 0x4c, 0x1f, 0x60, 0x16, 0xd7, 0x4f, 0x41, 0xe1,
      0xbb, 0x27, 0xc4, 0x27, 0x37, 0xd4, 0x7f, 0xb9, 0x10, 0xf8, 0xbc,
      0xaf, 0x93, 0x91, 0xb8, 0x88, 0x24, 0xb1, 0xf6, 0xf8, 0xbd, 0x31,
      0x96, 0x06, 0x76, 0xde, 0x32, 0xcd, 0x29, 0x29, 0xba, 0x70, 0x5f,
      0xea, 0xc0, 0xcb, 0xde, 0xc7, 0x75, 0x90, 0xe0, 0x0f, 0x5e, 0x2c,
      0x0d, 0x49, 0x20, 0xd5, 0x30, 0x83, 0xf8, 0x08,
#if !defined(BORINGSSL_FIPS_BREAK_DES)
      0x5a
#else
      0x00
#endif
  };
  static const uint8_t kPlaintextSHA1[20] = {
      0xc6, 0xf8, 0xc9, 0x63, 0x1c, 0x14, 0x23, 0x62, 0x9b, 0xbd,
      0x55, 0x82, 0xf4, 0xd6, 0x1d, 0xf2, 0xab, 0x7d, 0xc8,
#if !defined(BORINGSSL_FIPS_BREAK_SHA_1)
      0x28
#else
      0x00
#endif
  };
  static const uint8_t kPlaintextSHA256[32] = {
      0x37, 0xbd, 0x70, 0x53, 0x72, 0xfc, 0xd4, 0x03, 0x79, 0x70, 0xfb,
      0x06, 0x95, 0xb1, 0x2a, 0x82, 0x48, 0xe1, 0x3e, 0xf2, 0x33, 0xfb,
      0xef, 0x29, 0x81, 0x22, 0x45, 0x40, 0x43, 0x70, 0xce,
#if !defined(BORINGSSL_FIPS_BREAK_SHA_256)
      0x0f
#else
      0x00
#endif
  };
  static const uint8_t kPlaintextSHA512[64] = {
      0x08, 0x6a, 0x1c, 0x84, 0x61, 0x9d, 0x8e, 0xb3, 0xc0, 0x97, 0x4e,
      0xa1, 0x9f, 0x9c, 0xdc, 0xaf, 0x3b, 0x5c, 0x31, 0xf0, 0xf2, 0x74,
      0xc3, 0xbd, 0x6e, 0xd6, 0x1e, 0xb2, 0xbb, 0x34, 0x74, 0x72, 0x5c,
      0x51, 0x29, 0x8b, 0x87, 0x3a, 0xa3, 0xf2, 0x25, 0x23, 0xd4, 0x1c,
      0x82, 0x1b, 0xfe, 0xd3, 0xc6, 0xee, 0xb5, 0xd6, 0xaf, 0x07, 0x7b,
      0x98, 0xca, 0xa7, 0x01, 0xf3, 0x94, 0xf3, 0x68,
#if !defined(BORINGSSL_FIPS_BREAK_SHA_512)
      0x14
#else
      0x00
#endif
  };
  static const uint8_t kRSASignature[256] = {
      0x62, 0x66, 0x4b, 0xe3, 0xb1, 0xd2, 0x83, 0xf1, 0xa8, 0x56, 0x2b, 0x33,
      0x60, 0x1e, 0xdb, 0x1e, 0x06, 0xf7, 0xa7, 0x1e, 0xa8, 0xef, 0x03, 0x4d,
      0x0c, 0xf6, 0x83, 0x75, 0x7a, 0xf0, 0x14, 0xc7, 0xe2, 0x94, 0x3a, 0xb5,
      0x67, 0x56, 0xa5, 0x48, 0x7f, 0x3a, 0xa5, 0xbf, 0xf7, 0x1d, 0x44, 0xa6,
      0x34, 0xed, 0x9b, 0xd6, 0x51, 0xaa, 0x2c, 0x4e, 0xce, 0x60, 0x5f, 0xe9,
      0x0e, 0xd5, 0xcd, 0xeb, 0x23, 0x27, 0xf8, 0xfb, 0x45, 0xe5, 0x34, 0x63,
      0x77, 0x7f, 0x2e, 0x80, 0xcf, 0x9d, 0x2e, 0xfc, 0xe2, 0x50, 0x75, 0x29,
      0x46, 0xf4, 0xaf, 0x91, 0xed, 0x36, 0xe1, 0x5e, 0xef, 0x66, 0xa1, 0xff,
      0x27, 0xfc, 0x87, 0x7e, 0x60, 0x84, 0x0f, 0x54, 0x51, 0x56, 0x0f, 0x68,
      0x99, 0xc0, 0x3f, 0xeb, 0xa5, 0xa0, 0x46, 0xb0, 0x86, 0x02, 0xb0, 0xc8,
      0xe8, 0x46, 0x13, 0x06, 0xcd, 0xb7, 0x8a, 0xd0, 0x3b, 0x46, 0xd0, 0x14,
      0x64, 0x53, 0x9b, 0x5b, 0x5e, 0x02, 0x45, 0xba, 0x6e, 0x7e, 0x0a, 0xb9,
      0x9e, 0x62, 0xb7, 0xd5, 0x7a, 0x87, 0xea, 0xd3, 0x24, 0xa5, 0xef, 0xb3,
      0xdc, 0x05, 0x9c, 0x04, 0x60, 0x4b, 0xde, 0xa8, 0x90, 0x08, 0x7b, 0x6a,
      0x5f, 0xb4, 0x3f, 0xda, 0xc5, 0x1f, 0x6e, 0xd6, 0x15, 0xde, 0x65, 0xa4,
      0x6e, 0x62, 0x9d, 0x8f, 0xa8, 0xbe, 0x86, 0xf6, 0x09, 0x90, 0x40, 0xa5,
      0xf4, 0x23, 0xc5, 0xf6, 0x38, 0x86, 0x0d, 0x1c, 0xed, 0x4a, 0x0a, 0xae,
      0xa4, 0x26, 0xc2, 0x2e, 0xd3, 0x13, 0x66, 0x61, 0xea, 0x35, 0x01, 0x0e,
      0x13, 0xda, 0x78, 0x20, 0xae, 0x59, 0x5f, 0x9b, 0xa9, 0x6c, 0xf9, 0x1b,
      0xdf, 0x76, 0x53, 0xc8, 0xa7, 0xf5, 0x63, 0x6d, 0xf3, 0xff, 0xfd, 0xaf,
      0x75, 0x4b, 0xac, 0x67, 0xb1, 0x3c, 0xbf, 0x5e, 0xde, 0x73, 0x02, 0x6d,
      0xd2, 0x0c, 0xb1,
#if !defined(BORINGSSL_FIPS_BREAK_RSA_SIG)
      0x64
#else
      0x00
#endif
  };
  const uint8_t kDRBGEntropy[48] =
      "BCM Known Answer Test DBRG Initial Entropy      ";
  const uint8_t kDRBGPersonalization[18] = "BCMPersonalization";
  const uint8_t kDRBGAD[16] = "BCM DRBG KAT AD ";
  const uint8_t kDRBGOutput[64] = {
      0x1d, 0x63, 0xdf, 0x05, 0x51, 0x49, 0x22, 0x46, 0xcd, 0x9b, 0xc5,
      0xbb, 0xf1, 0x5d, 0x44, 0xae, 0x13, 0x78, 0xb1, 0xe4, 0x7c, 0xf1,
      0x96, 0x33, 0x3d, 0x60, 0xb6, 0x29, 0xd4, 0xbb, 0x6b, 0x44, 0xf9,
      0xef, 0xd9, 0xf4, 0xa2, 0xba, 0x48, 0xea, 0x39, 0x75, 0x59, 0x32,
      0xf7, 0x31, 0x2c, 0x98, 0x14, 0x2b, 0x49, 0xdf, 0x02, 0xb6, 0x5d,
      0x71, 0x09, 0x50, 0xdb, 0x23, 0xdb, 0xe5, 0x22,
#if !defined(BORINGSSL_FIPS_BREAK_DRBG)
      0x95
#else
      0x00
#endif
  };
  const uint8_t kDRBGEntropy2[48] =
      "BCM Known Answer Test DBRG Reseed Entropy       ";
  const uint8_t kDRBGReseedOutput[64] = {
      0xa4, 0x77, 0x05, 0xdb, 0x14, 0x11, 0x76, 0x71, 0x42, 0x5b, 0xd8,
      0xd7, 0xa5, 0x4f, 0x8b, 0x39, 0xf2, 0x10, 0x4a, 0x50, 0x5b, 0xa2,
      0xc8, 0xf0, 0xbb, 0x3e, 0xa1, 0xa5, 0x90, 0x7d, 0x54, 0xd9, 0xc6,
      0xb0, 0x96, 0xc0, 0x2b, 0x7e, 0x9b, 0xc9, 0xa1, 0xdd, 0x78, 0x2e,
      0xd5, 0xa8, 0x66, 0x16, 0xbd, 0x18, 0x3c, 0xf2, 0xaa, 0x7a, 0x2b,
      0x37, 0xf9, 0xab, 0x35, 0x64, 0x15, 0x01, 0x3f, 0xc4,
  };
  const uint8_t kECDSASigR[32] = {
      0x67, 0x80, 0xc5, 0xfc, 0x70, 0x27, 0x5e, 0x2c, 0x70, 0x61, 0xa0,
      0xe7, 0x87, 0x7b, 0xb1, 0x74, 0xde, 0xad, 0xeb, 0x98, 0x87, 0x02,
      0x7f, 0x3f, 0xa8, 0x36, 0x54, 0x15, 0x8b, 0xa7, 0xf5,
#if !defined(BORINGSSL_FIPS_BREAK_ECDSA_SIG)
      0x0c,
#else
      0x00,
#endif
  };
  const uint8_t kECDSASigS[32] = {
      0xa5, 0x93, 0xe0, 0x23, 0x91, 0xe7, 0x4b, 0x8d, 0x77, 0x25, 0xa6,
      0xba, 0x4d, 0xd9, 0x86, 0x77, 0xda, 0x7d, 0x8f, 0xef, 0xc4, 0x1a,
      0xf0, 0xcc, 0x81, 0xe5, 0xea, 0x3f, 0xc2, 0x41, 0x7f, 0xd8,
  };

  EVP_AEAD_CTX aead_ctx;
  EVP_AEAD_CTX_zero(&aead_ctx);
  RSA *rsa_key = NULL;
  EC_KEY *ec_key = NULL;
  ECDSA_SIG *sig = NULL;
  int ret = 0;

  AES_KEY aes_key;
  uint8_t aes_iv[16];
  uint8_t output[256];

  // AES-CBC Encryption KAT
  memcpy(aes_iv, kAESIV, sizeof(kAESIV));
  if (AES_set_encrypt_key(kAESKey, 8 * sizeof(kAESKey), &aes_key) != 0) {
    goto err;
  }
  AES_cbc_encrypt(kPlaintext, output, sizeof(kPlaintext), &aes_key, aes_iv,
                  AES_ENCRYPT);
  if (!check_test(kAESCBCCiphertext, output, sizeof(kAESCBCCiphertext),
                  "AES-CBC Encryption KAT")) {
    goto err;
  }

  // AES-CBC Decryption KAT
  memcpy(aes_iv, kAESIV, sizeof(kAESIV));
  if (AES_set_decrypt_key(kAESKey, 8 * sizeof(kAESKey), &aes_key) != 0) {
    goto err;
  }
  AES_cbc_encrypt(kAESCBCCiphertext, output, sizeof(kAESCBCCiphertext),
                  &aes_key, aes_iv, AES_DECRYPT);
  if (!check_test(kPlaintext, output, sizeof(kPlaintext),
                  "AES-CBC Decryption KAT")) {
    goto err;
  }

  size_t out_len;
  uint8_t nonce[EVP_AEAD_MAX_NONCE_LENGTH];
  OPENSSL_memset(nonce, 0, sizeof(nonce));
  if (!EVP_AEAD_CTX_init(&aead_ctx, EVP_aead_aes_128_gcm(), kAESKey,
                         sizeof(kAESKey), 0, NULL)) {
    goto err;
  }

  // AES-GCM Encryption KAT
  if (!EVP_AEAD_CTX_seal(&aead_ctx, output, &out_len, sizeof(output), nonce,
                         EVP_AEAD_nonce_length(EVP_aead_aes_128_gcm()),
                         kPlaintext, sizeof(kPlaintext), NULL, 0) ||
      !check_test(kAESGCMCiphertext, output, sizeof(kAESGCMCiphertext),
                  "AES-GCM Encryption KAT")) {
    goto err;
  }

  // AES-GCM Decryption KAT
  if (!EVP_AEAD_CTX_open(&aead_ctx, output, &out_len, sizeof(output), nonce,
                         EVP_AEAD_nonce_length(EVP_aead_aes_128_gcm()),
                         kAESGCMCiphertext, sizeof(kAESGCMCiphertext), NULL,
                         0) ||
      !check_test(kPlaintext, output, sizeof(kPlaintext),
                  "AES-GCM Decryption KAT")) {
    goto err;
  }

  DES_key_schedule des1, des2, des3;
  DES_cblock des_iv;
  DES_set_key(&kDESKey1, &des1);
  DES_set_key(&kDESKey2, &des2);
  DES_set_key(&kDESKey3, &des3);

  // 3DES Encryption KAT
  memcpy(&des_iv, &kDESIV, sizeof(des_iv));
  DES_ede3_cbc_encrypt(kPlaintext, output, sizeof(kPlaintext), &des1, &des2,
                       &des3, &des_iv, DES_ENCRYPT);
  if (!check_test(kDESCiphertext, output, sizeof(kDESCiphertext),
                  "3DES Encryption KAT")) {
    goto err;
  }

  // 3DES Decryption KAT
  memcpy(&des_iv, &kDESIV, sizeof(des_iv));
  DES_ede3_cbc_encrypt(kDESCiphertext, output, sizeof(kDESCiphertext), &des1,
                       &des2, &des3, &des_iv, DES_DECRYPT);
  if (!check_test(kPlaintext, output, sizeof(kPlaintext),
                  "3DES Decryption KAT")) {
    goto err;
  }

  // SHA-1 KAT
  SHA1(kPlaintext, sizeof(kPlaintext), output);
  if (!check_test(kPlaintextSHA1, output, sizeof(kPlaintextSHA1),
                  "SHA-1 KAT")) {
    goto err;
  }

  // SHA-256 KAT
  SHA256(kPlaintext, sizeof(kPlaintext), output);
  if (!check_test(kPlaintextSHA256, output, sizeof(kPlaintextSHA256),
                  "SHA-256 KAT")) {
    goto err;
  }

  // SHA-512 KAT
  SHA512(kPlaintext, sizeof(kPlaintext), output);
  if (!check_test(kPlaintextSHA512, output, sizeof(kPlaintextSHA512),
                  "SHA-512 KAT")) {
    goto err;
  }

  rsa_key = self_test_rsa_key();
  if (rsa_key == NULL) {
    fprintf(stderr, "RSA KeyGen failed\n");
    goto err;
  }

  // RSA Sign KAT
  unsigned sig_len;

  // Disable blinding for the power-on tests because it's not needed and
  // triggers an entropy draw.
  rsa_key->flags |= RSA_FLAG_NO_BLINDING;

  if (!RSA_sign(NID_sha256, kPlaintextSHA256, sizeof(kPlaintextSHA256), output,
                &sig_len, rsa_key) ||
      !check_test(kRSASignature, output, sizeof(kRSASignature),
                  "RSA Sign KAT")) {
    goto err;
  }

  // RSA Verify KAT
  if (!RSA_verify(NID_sha256, kPlaintextSHA256, sizeof(kPlaintextSHA256),
                  kRSASignature, sizeof(kRSASignature), rsa_key)) {
    fprintf(stderr, "RSA Verify KAT failed.\n");
    goto err;
  }

  ec_key = self_test_ecdsa_key();
  if (ec_key == NULL) {
    fprintf(stderr, "ECDSA KeyGen failed\n");
    goto err;
  }

  // ECDSA Sign/Verify PWCT

  // The 'k' value for ECDSA is fixed to avoid an entropy draw.
  ec_key->fixed_k = BN_new();
  if (ec_key->fixed_k == NULL ||
      !BN_set_word(ec_key->fixed_k, 42)) {
    fprintf(stderr, "Out of memory\n");
    goto err;
  }

  sig = ECDSA_do_sign(kPlaintextSHA256, sizeof(kPlaintextSHA256), ec_key);

  uint8_t ecdsa_r_bytes[sizeof(kECDSASigR)];
  uint8_t ecdsa_s_bytes[sizeof(kECDSASigS)];
  if (sig == NULL ||
      BN_num_bytes(sig->r) != sizeof(ecdsa_r_bytes) ||
      !BN_bn2bin(sig->r, ecdsa_r_bytes) ||
      BN_num_bytes(sig->s) != sizeof(ecdsa_s_bytes) ||
      !BN_bn2bin(sig->s, ecdsa_s_bytes) ||
      !check_test(kECDSASigR, ecdsa_r_bytes, sizeof(kECDSASigR), "ECDSA R") ||
      !check_test(kECDSASigS, ecdsa_s_bytes, sizeof(kECDSASigS), "ECDSA S")) {
    fprintf(stderr, "ECDSA KAT failed.\n");
    goto err;
  }

  // DBRG KAT
  CTR_DRBG_STATE drbg;
  if (!CTR_DRBG_init(&drbg, kDRBGEntropy, kDRBGPersonalization,
                     sizeof(kDRBGPersonalization)) ||
      !CTR_DRBG_generate(&drbg, output, sizeof(kDRBGOutput), kDRBGAD,
                         sizeof(kDRBGAD)) ||
      !check_test(kDRBGOutput, output, sizeof(kDRBGOutput),
                  "DBRG Generate KAT") ||
      !CTR_DRBG_reseed(&drbg, kDRBGEntropy2, kDRBGAD, sizeof(kDRBGAD)) ||
      !CTR_DRBG_generate(&drbg, output, sizeof(kDRBGReseedOutput), kDRBGAD,
                         sizeof(kDRBGAD)) ||
      !check_test(kDRBGReseedOutput, output, sizeof(kDRBGReseedOutput),
                  "DRBG Reseed KAT")) {
    goto err;
  }
  CTR_DRBG_clear(&drbg);

  CTR_DRBG_STATE kZeroDRBG;
  memset(&kZeroDRBG, 0, sizeof(kZeroDRBG));
  if (!check_test(&kZeroDRBG, &drbg, sizeof(drbg), "DRBG Clear KAT")) {
    goto err;
  }

  ret = 1;

err:
  EVP_AEAD_CTX_cleanup(&aead_ctx);
  RSA_free(rsa_key);
  EC_KEY_free(ec_key);
  ECDSA_SIG_free(sig);

  return ret;
}
Exemple #5
0
// bn_mul_part_recursive sets |r| to |a| * |b|, using |t| as scratch space. |r|
// has length 4*|n|, |a| has length |n| + |tna|, |b| has length |n| + |tnb|, and
// |t| has length 8*|n|. |n| must be a power of two. Additionally, we must have
// 0 <= tna < n and 0 <= tnb < n, and |tna| and |tnb| must differ by at most
// one.
//
// TODO(davidben): Make this take |size_t| and perhaps the actual lengths of |a|
// and |b|.
static void bn_mul_part_recursive(BN_ULONG *r, const BN_ULONG *a,
                                  const BN_ULONG *b, int n, int tna, int tnb,
                                  BN_ULONG *t) {
  // |n| is a power of two.
  assert(n != 0 && (n & (n - 1)) == 0);
  // Check |tna| and |tnb| are in range.
  assert(0 <= tna && tna < n);
  assert(0 <= tnb && tnb < n);
  assert(-1 <= tna - tnb && tna - tnb <= 1);

  int n2 = n * 2;
  if (n < 8) {
    bn_mul_normal(r, a, n + tna, b, n + tnb);
    OPENSSL_memset(r + n2 + tna + tnb, 0, n2 - tna - tnb);
    return;
  }

  // Split |a| and |b| into a0,a1 and b0,b1, where a0 and b0 have size |n|. |a1|
  // and |b1| have size |tna| and |tnb|, respectively.
  // Split |t| into t0,t1,t2,t3, each of size |n|, with the remaining 4*|n| used
  // for recursive calls.
  // Split |r| into r0,r1,r2,r3. We must contribute a0*b0 to r0,r1, a0*a1+b0*b1
  // to r1,r2, and a1*b1 to r2,r3. The middle term we will compute as:
  //
  //   a0*a1 + b0*b1 = (a0 - a1)*(b1 - b0) + a1*b1 + a0*b0

  // t0 = a0 - a1 and t1 = b1 - b0. The result will be multiplied, so we XOR
  // their sign masks, giving the sign of (a0 - a1)*(b1 - b0). t0 and t1
  // themselves store the absolute value.
  BN_ULONG neg = bn_abs_sub_part_words(t, a, &a[n], tna, n - tna, &t[n2]);
  neg ^= bn_abs_sub_part_words(&t[n], &b[n], b, tnb, tnb - n, &t[n2]);

  // Compute:
  // t2,t3 = t0 * t1 = |(a0 - a1)*(b1 - b0)|
  // r0,r1 = a0 * b0
  // r2,r3 = a1 * b1
  if (n == 8) {
    bn_mul_comba8(&t[n2], t, &t[n]);
    bn_mul_comba8(r, a, b);

    bn_mul_normal(&r[n2], &a[n], tna, &b[n], tnb);
    // |bn_mul_normal| only writes |tna| + |tna| words. Zero the rest.
    OPENSSL_memset(&r[n2 + tna + tnb], 0, sizeof(BN_ULONG) * (n2 - tna - tnb));
  } else {
    BN_ULONG *p = &t[n2 * 2];
    bn_mul_recursive(&t[n2], t, &t[n], n, 0, 0, p);
    bn_mul_recursive(r, a, b, n, 0, 0, p);

    OPENSSL_memset(&r[n2], 0, sizeof(BN_ULONG) * n2);
    if (tna < BN_MUL_RECURSIVE_SIZE_NORMAL &&
        tnb < BN_MUL_RECURSIVE_SIZE_NORMAL) {
      bn_mul_normal(&r[n2], &a[n], tna, &b[n], tnb);
    } else {
      int i = n;
      for (;;) {
        i /= 2;
        if (i < tna || i < tnb) {
          // E.g., n == 16, i == 8 and tna == 11. |tna| and |tnb| are within one
          // of each other, so if |tna| is larger and tna > i, then we know
          // tnb >= i, and this call is valid.
          bn_mul_part_recursive(&r[n2], &a[n], &b[n], i, tna - i, tnb - i, p);
          break;
        }
        if (i == tna || i == tnb) {
          // If there is only a bottom half to the number, just do it. We know
          // the larger of |tna - i| and |tnb - i| is zero. The other is zero or
          // -1 by because of |tna| and |tnb| differ by at most one.
          bn_mul_recursive(&r[n2], &a[n], &b[n], i, tna - i, tnb - i, p);
          break;
        }

        // This loop will eventually terminate when |i| falls below
        // |BN_MUL_RECURSIVE_SIZE_NORMAL| because we know one of |tna| and |tnb|
        // exceeds that.
      }
    }
  }

  // t0,t1,c = r0,r1 + r2,r3 = a0*b0 + a1*b1
  BN_ULONG c = bn_add_words(t, r, &r[n2], n2);

  // t2,t3,c = t0,t1,c + neg*t2,t3 = (a0 - a1)*(b1 - b0) + a1*b1 + a0*b0.
  // The second term is stored as the absolute value, so we do this with a
  // constant-time select.
  BN_ULONG c_neg = c - bn_sub_words(&t[n2 * 2], t, &t[n2], n2);
  BN_ULONG c_pos = c + bn_add_words(&t[n2], t, &t[n2], n2);
  bn_select_words(&t[n2], neg, &t[n2 * 2], &t[n2], n2);
  OPENSSL_COMPILE_ASSERT(sizeof(BN_ULONG) <= sizeof(crypto_word_t),
                         crypto_word_t_too_small);
  c = constant_time_select_w(neg, c_neg, c_pos);

  // We now have our three components. Add them together.
  // r1,r2,c = r1,r2 + t2,t3,c
  c += bn_add_words(&r[n], &r[n], &t[n2], n2);

  // Propagate the carry bit to the end.
  for (int i = n + n2; i < n2 + n2; i++) {
    BN_ULONG old = r[i];
    r[i] = old + c;
    c = r[i] < old;
  }

  // The product should fit without carries.
  assert(c == 0);
}
Exemple #6
0
// bn_mul_recursive sets |r| to |a| * |b|, using |t| as scratch space. |r| has
// length 2*|n2|, |a| has length |n2| + |dna|, |b| has length |n2| + |dnb|, and
// |t| has length 4*|n2|. |n2| must be a power of two. Finally, we must have
// -|BN_MUL_RECURSIVE_SIZE_NORMAL|/2 <= |dna| <= 0 and
// -|BN_MUL_RECURSIVE_SIZE_NORMAL|/2 <= |dnb| <= 0.
//
// TODO(davidben): Simplify and |size_t| the calling convention around lengths
// here.
static void bn_mul_recursive(BN_ULONG *r, const BN_ULONG *a, const BN_ULONG *b,
                             int n2, int dna, int dnb, BN_ULONG *t) {
  // |n2| is a power of two.
  assert(n2 != 0 && (n2 & (n2 - 1)) == 0);
  // Check |dna| and |dnb| are in range.
  assert(-BN_MUL_RECURSIVE_SIZE_NORMAL/2 <= dna && dna <= 0);
  assert(-BN_MUL_RECURSIVE_SIZE_NORMAL/2 <= dnb && dnb <= 0);

  // Only call bn_mul_comba 8 if n2 == 8 and the
  // two arrays are complete [steve]
  if (n2 == 8 && dna == 0 && dnb == 0) {
    bn_mul_comba8(r, a, b);
    return;
  }

  // Else do normal multiply
  if (n2 < BN_MUL_RECURSIVE_SIZE_NORMAL) {
    bn_mul_normal(r, a, n2 + dna, b, n2 + dnb);
    if (dna + dnb < 0) {
      OPENSSL_memset(&r[2 * n2 + dna + dnb], 0,
                     sizeof(BN_ULONG) * -(dna + dnb));
    }
    return;
  }

  // Split |a| and |b| into a0,a1 and b0,b1, where a0 and b0 have size |n|.
  // Split |t| into t0,t1,t2,t3, each of size |n|, with the remaining 4*|n| used
  // for recursive calls.
  // Split |r| into r0,r1,r2,r3. We must contribute a0*b0 to r0,r1, a0*a1+b0*b1
  // to r1,r2, and a1*b1 to r2,r3. The middle term we will compute as:
  //
  //   a0*a1 + b0*b1 = (a0 - a1)*(b1 - b0) + a1*b1 + a0*b0
  //
  // Note that we know |n| >= |BN_MUL_RECURSIVE_SIZE_NORMAL|/2 above, so
  // |tna| and |tnb| are non-negative.
  int n = n2 / 2, tna = n + dna, tnb = n + dnb;

  // t0 = a0 - a1 and t1 = b1 - b0. The result will be multiplied, so we XOR
  // their sign masks, giving the sign of (a0 - a1)*(b1 - b0). t0 and t1
  // themselves store the absolute value.
  BN_ULONG neg = bn_abs_sub_part_words(t, a, &a[n], tna, n - tna, &t[n2]);
  neg ^= bn_abs_sub_part_words(&t[n], &b[n], b, tnb, tnb - n, &t[n2]);

  // Compute:
  // t2,t3 = t0 * t1 = |(a0 - a1)*(b1 - b0)|
  // r0,r1 = a0 * b0
  // r2,r3 = a1 * b1
  if (n == 4 && dna == 0 && dnb == 0) {
    bn_mul_comba4(&t[n2], t, &t[n]);

    bn_mul_comba4(r, a, b);
    bn_mul_comba4(&r[n2], &a[n], &b[n]);
  } else if (n == 8 && dna == 0 && dnb == 0) {
    bn_mul_comba8(&t[n2], t, &t[n]);

    bn_mul_comba8(r, a, b);
    bn_mul_comba8(&r[n2], &a[n], &b[n]);
  } else {
    BN_ULONG *p = &t[n2 * 2];
    bn_mul_recursive(&t[n2], t, &t[n], n, 0, 0, p);
    bn_mul_recursive(r, a, b, n, 0, 0, p);
    bn_mul_recursive(&r[n2], &a[n], &b[n], n, dna, dnb, p);
  }

  // t0,t1,c = r0,r1 + r2,r3 = a0*b0 + a1*b1
  BN_ULONG c = bn_add_words(t, r, &r[n2], n2);

  // t2,t3,c = t0,t1,c + neg*t2,t3 = (a0 - a1)*(b1 - b0) + a1*b1 + a0*b0.
  // The second term is stored as the absolute value, so we do this with a
  // constant-time select.
  BN_ULONG c_neg = c - bn_sub_words(&t[n2 * 2], t, &t[n2], n2);
  BN_ULONG c_pos = c + bn_add_words(&t[n2], t, &t[n2], n2);
  bn_select_words(&t[n2], neg, &t[n2 * 2], &t[n2], n2);
  OPENSSL_COMPILE_ASSERT(sizeof(BN_ULONG) <= sizeof(crypto_word_t),
                         crypto_word_t_too_small);
  c = constant_time_select_w(neg, c_neg, c_pos);

  // We now have our three components. Add them together.
  // r1,r2,c = r1,r2 + t2,t3,c
  c += bn_add_words(&r[n], &r[n], &t[n2], n2);

  // Propagate the carry bit to the end.
  for (int i = n + n2; i < n2 + n2; i++) {
    BN_ULONG old = r[i];
    r[i] = old + c;
    c = r[i] < old;
  }

  // The product should fit without carries.
  assert(c == 0);
}
Exemple #7
0
/* r is 2*n words in size,
 * a and b are both n words in size.    (There's not actually a 'b' here ...)
 * n must be a power of 2.
 * We multiply and return the result.
 * t must be 2*n words in size
 * We calculate
 * a[0]*b[0]
 * a[0]*b[0]+a[1]*b[1]+(a[0]-a[1])*(b[1]-b[0])
 * a[1]*b[1]
 */
static void bn_sqr_recursive(BN_ULONG *r, const BN_ULONG *a, int n2, BN_ULONG *t) {
  int n = n2 / 2;
  int zero, c1;
  BN_ULONG ln, lo, *p;

  if (n2 == 4) {
    bn_sqr_comba4(r, a);
    return;
  } else if (n2 == 8) {
    bn_sqr_comba8(r, a);
    return;
  }
  if (n2 < BN_SQR_RECURSIVE_SIZE_NORMAL) {
    bn_sqr_normal(r, a, n2, t);
    return;
  }
  /* r=(a[0]-a[1])*(a[1]-a[0]) */
  c1 = bn_cmp_words(a, &(a[n]), n);
  zero = 0;
  if (c1 > 0) {
    bn_sub_words(t, a, &(a[n]), n);
  } else if (c1 < 0) {
    bn_sub_words(t, &(a[n]), a, n);
  } else {
    zero = 1;
  }

  /* The result will always be negative unless it is zero */
  p = &(t[n2 * 2]);

  if (!zero) {
    bn_sqr_recursive(&(t[n2]), t, n, p);
  } else {
    OPENSSL_memset(&(t[n2]), 0, n2 * sizeof(BN_ULONG));
  }
  bn_sqr_recursive(r, a, n, p);
  bn_sqr_recursive(&(r[n2]), &(a[n]), n, p);

  /* t[32] holds (a[0]-a[1])*(a[1]-a[0]), it is negative or zero
   * r[10] holds (a[0]*b[0])
   * r[32] holds (b[1]*b[1]) */

  c1 = (int)(bn_add_words(t, r, &(r[n2]), n2));

  /* t[32] is negative */
  c1 -= (int)(bn_sub_words(&(t[n2]), t, &(t[n2]), n2));

  /* t[32] holds (a[0]-a[1])*(a[1]-a[0])+(a[0]*a[0])+(a[1]*a[1])
   * r[10] holds (a[0]*a[0])
   * r[32] holds (a[1]*a[1])
   * c1 holds the carry bits */
  c1 += (int)(bn_add_words(&(r[n]), &(r[n]), &(t[n2]), n2));
  if (c1) {
    p = &(r[n + n2]);
    lo = *p;
    ln = (lo + c1) & BN_MASK2;
    *p = ln;

    /* The overflow will stop before we over write
     * words we should not overwrite */
    if (ln < (BN_ULONG)c1) {
      do {
        p++;
        lo = *p;
        ln = (lo + 1) & BN_MASK2;
        *p = ln;
      } while (ln == 0);
    }
  }
}
Exemple #8
0
/* tnX may not be negative but less than n */
static void bn_mul_part_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n,
                                  int tna, int tnb, BN_ULONG *t) {
  int i, j, n2 = n * 2;
  int c1, c2, neg;
  BN_ULONG ln, lo, *p;

  if (n < 8) {
    bn_mul_normal(r, a, n + tna, b, n + tnb);
    return;
  }

  /* r=(a[0]-a[1])*(b[1]-b[0]) */
  c1 = bn_cmp_part_words(a, &(a[n]), tna, n - tna);
  c2 = bn_cmp_part_words(&(b[n]), b, tnb, tnb - n);
  neg = 0;
  switch (c1 * 3 + c2) {
    case -4:
      bn_sub_part_words(t, &(a[n]), a, tna, tna - n);       /* - */
      bn_sub_part_words(&(t[n]), b, &(b[n]), tnb, n - tnb); /* - */
      break;
    case -3:
    /* break; */
    case -2:
      bn_sub_part_words(t, &(a[n]), a, tna, tna - n);       /* - */
      bn_sub_part_words(&(t[n]), &(b[n]), b, tnb, tnb - n); /* + */
      neg = 1;
      break;
    case -1:
    case 0:
    case 1:
    /* break; */
    case 2:
      bn_sub_part_words(t, a, &(a[n]), tna, n - tna);       /* + */
      bn_sub_part_words(&(t[n]), b, &(b[n]), tnb, n - tnb); /* - */
      neg = 1;
      break;
    case 3:
    /* break; */
    case 4:
      bn_sub_part_words(t, a, &(a[n]), tna, n - tna);
      bn_sub_part_words(&(t[n]), &(b[n]), b, tnb, tnb - n);
      break;
  }

  if (n == 8) {
    bn_mul_comba8(&(t[n2]), t, &(t[n]));
    bn_mul_comba8(r, a, b);
    bn_mul_normal(&(r[n2]), &(a[n]), tna, &(b[n]), tnb);
    OPENSSL_memset(&(r[n2 + tna + tnb]), 0, sizeof(BN_ULONG) * (n2 - tna - tnb));
  } else {
    p = &(t[n2 * 2]);
    bn_mul_recursive(&(t[n2]), t, &(t[n]), n, 0, 0, p);
    bn_mul_recursive(r, a, b, n, 0, 0, p);
    i = n / 2;
    /* If there is only a bottom half to the number,
     * just do it */
    if (tna > tnb) {
      j = tna - i;
    } else {
      j = tnb - i;
    }

    if (j == 0) {
      bn_mul_recursive(&(r[n2]), &(a[n]), &(b[n]), i, tna - i, tnb - i, p);
      OPENSSL_memset(&(r[n2 + i * 2]), 0, sizeof(BN_ULONG) * (n2 - i * 2));
    } else if (j > 0) {
      /* eg, n == 16, i == 8 and tn == 11 */
      bn_mul_part_recursive(&(r[n2]), &(a[n]), &(b[n]), i, tna - i, tnb - i, p);
      OPENSSL_memset(&(r[n2 + tna + tnb]), 0,
                     sizeof(BN_ULONG) * (n2 - tna - tnb));
    } else {
      /* (j < 0) eg, n == 16, i == 8 and tn == 5 */
      OPENSSL_memset(&(r[n2]), 0, sizeof(BN_ULONG) * n2);
      if (tna < BN_MUL_RECURSIVE_SIZE_NORMAL &&
          tnb < BN_MUL_RECURSIVE_SIZE_NORMAL) {
        bn_mul_normal(&(r[n2]), &(a[n]), tna, &(b[n]), tnb);
      } else {
        for (;;) {
          i /= 2;
          /* these simplified conditions work
           * exclusively because difference
           * between tna and tnb is 1 or 0 */
          if (i < tna || i < tnb) {
            bn_mul_part_recursive(&(r[n2]), &(a[n]), &(b[n]), i, tna - i,
                                  tnb - i, p);
            break;
          } else if (i == tna || i == tnb) {
            bn_mul_recursive(&(r[n2]), &(a[n]), &(b[n]), i, tna - i, tnb - i,
                             p);
            break;
          }
        }
      }
    }
  }

  /* t[32] holds (a[0]-a[1])*(b[1]-b[0]), c1 is the sign
   * r[10] holds (a[0]*b[0])
   * r[32] holds (b[1]*b[1])
   */

  c1 = (int)(bn_add_words(t, r, &(r[n2]), n2));

  if (neg) {
    /* if t[32] is negative */
    c1 -= (int)(bn_sub_words(&(t[n2]), t, &(t[n2]), n2));
  } else {
    /* Might have a carry */
    c1 += (int)(bn_add_words(&(t[n2]), &(t[n2]), t, n2));
  }

  /* t[32] holds (a[0]-a[1])*(b[1]-b[0])+(a[0]*b[0])+(a[1]*b[1])
   * r[10] holds (a[0]*b[0])
   * r[32] holds (b[1]*b[1])
   * c1 holds the carry bits */
  c1 += (int)(bn_add_words(&(r[n]), &(r[n]), &(t[n2]), n2));
  if (c1) {
    p = &(r[n + n2]);
    lo = *p;
    ln = (lo + c1) & BN_MASK2;
    *p = ln;

    /* The overflow will stop before we over write
     * words we should not overwrite */
    if (ln < (BN_ULONG)c1) {
      do {
        p++;
        lo = *p;
        ln = (lo + 1) & BN_MASK2;
        *p = ln;
      } while (ln == 0);
    }
  }
}
Exemple #9
0
/* dnX may not be positive, but n2/2+dnX has to be */
static void bn_mul_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n2,
                             int dna, int dnb, BN_ULONG *t) {
  int n = n2 / 2, c1, c2;
  int tna = n + dna, tnb = n + dnb;
  unsigned int neg, zero;
  BN_ULONG ln, lo, *p;

  /* Only call bn_mul_comba 8 if n2 == 8 and the
   * two arrays are complete [steve]
   */
  if (n2 == 8 && dna == 0 && dnb == 0) {
    bn_mul_comba8(r, a, b);
    return;
  }

  /* Else do normal multiply */
  if (n2 < BN_MUL_RECURSIVE_SIZE_NORMAL) {
    bn_mul_normal(r, a, n2 + dna, b, n2 + dnb);
    if ((dna + dnb) < 0) {
      OPENSSL_memset(&r[2 * n2 + dna + dnb], 0,
                     sizeof(BN_ULONG) * -(dna + dnb));
    }
    return;
  }

  /* r=(a[0]-a[1])*(b[1]-b[0]) */
  c1 = bn_cmp_part_words(a, &(a[n]), tna, n - tna);
  c2 = bn_cmp_part_words(&(b[n]), b, tnb, tnb - n);
  zero = neg = 0;
  switch (c1 * 3 + c2) {
    case -4:
      bn_sub_part_words(t, &(a[n]), a, tna, tna - n);       /* - */
      bn_sub_part_words(&(t[n]), b, &(b[n]), tnb, n - tnb); /* - */
      break;
    case -3:
      zero = 1;
      break;
    case -2:
      bn_sub_part_words(t, &(a[n]), a, tna, tna - n);       /* - */
      bn_sub_part_words(&(t[n]), &(b[n]), b, tnb, tnb - n); /* + */
      neg = 1;
      break;
    case -1:
    case 0:
    case 1:
      zero = 1;
      break;
    case 2:
      bn_sub_part_words(t, a, &(a[n]), tna, n - tna);       /* + */
      bn_sub_part_words(&(t[n]), b, &(b[n]), tnb, n - tnb); /* - */
      neg = 1;
      break;
    case 3:
      zero = 1;
      break;
    case 4:
      bn_sub_part_words(t, a, &(a[n]), tna, n - tna);
      bn_sub_part_words(&(t[n]), &(b[n]), b, tnb, tnb - n);
      break;
  }

  if (n == 4 && dna == 0 && dnb == 0) {
    /* XXX: bn_mul_comba4 could take extra args to do this well */
    if (!zero) {
      bn_mul_comba4(&(t[n2]), t, &(t[n]));
    } else {
      OPENSSL_memset(&(t[n2]), 0, 8 * sizeof(BN_ULONG));
    }

    bn_mul_comba4(r, a, b);
    bn_mul_comba4(&(r[n2]), &(a[n]), &(b[n]));
  } else if (n == 8 && dna == 0 && dnb == 0) {
    /* XXX: bn_mul_comba8 could take extra args to do this well */
    if (!zero) {
      bn_mul_comba8(&(t[n2]), t, &(t[n]));
    } else {
      OPENSSL_memset(&(t[n2]), 0, 16 * sizeof(BN_ULONG));
    }

    bn_mul_comba8(r, a, b);
    bn_mul_comba8(&(r[n2]), &(a[n]), &(b[n]));
  } else {
    p = &(t[n2 * 2]);
    if (!zero) {
      bn_mul_recursive(&(t[n2]), t, &(t[n]), n, 0, 0, p);
    } else {
      OPENSSL_memset(&(t[n2]), 0, n2 * sizeof(BN_ULONG));
    }
    bn_mul_recursive(r, a, b, n, 0, 0, p);
    bn_mul_recursive(&(r[n2]), &(a[n]), &(b[n]), n, dna, dnb, p);
  }

  /* t[32] holds (a[0]-a[1])*(b[1]-b[0]), c1 is the sign
   * r[10] holds (a[0]*b[0])
   * r[32] holds (b[1]*b[1]) */

  c1 = (int)(bn_add_words(t, r, &(r[n2]), n2));

  if (neg) {
    /* if t[32] is negative */
    c1 -= (int)(bn_sub_words(&(t[n2]), t, &(t[n2]), n2));
  } else {
    /* Might have a carry */
    c1 += (int)(bn_add_words(&(t[n2]), &(t[n2]), t, n2));
  }

  /* t[32] holds (a[0]-a[1])*(b[1]-b[0])+(a[0]*b[0])+(a[1]*b[1])
   * r[10] holds (a[0]*b[0])
   * r[32] holds (b[1]*b[1])
   * c1 holds the carry bits */
  c1 += (int)(bn_add_words(&(r[n]), &(r[n]), &(t[n2]), n2));
  if (c1) {
    p = &(r[n + n2]);
    lo = *p;
    ln = (lo + c1) & BN_MASK2;
    *p = ln;

    /* The overflow will stop before we over write
     * words we should not overwrite */
    if (ln < (BN_ULONG)c1) {
      do {
        p++;
        lo = *p;
        ln = (lo + 1) & BN_MASK2;
        *p = ln;
      } while (ln == 0);
    }
  }
}