// Copyright 1999-2016 The OpenSSL Project Authors. All Rights Reserved.

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//     https://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

#include <openssl/pkcs8.h>

#include <limits.h>

#include <string.h>

#include <openssl/bytestring.h>

#include <openssl/cipher.h>

#include <openssl/digest.h>

#include <openssl/err.h>

#include <openssl/mem.h>

#include <openssl/nid.h>

#include <openssl/rand.h>

#include "../internal.h"

#include "internal.h"

using namespace bssl;

// 1.2.840.113549.1.5.12

static const uint8_t kPBKDF2[] = {0x2a, 0x86, 0x48, 0x86, 0xf7,

                                  0x0d, 0x01, 0x05, 0x0c};

// 1.2.840.113549.1.5.13

static const uint8_t kPBES2[] = {0x2a, 0x86, 0x48, 0x86, 0xf7,

                                 0x0d, 0x01, 0x05, 0x0d};

// 1.2.840.113549.2.7

static const uint8_t kHMACWithSHA1[] = {0x2a, 0x86, 0x48, 0x86,

                                        0xf7, 0x0d, 0x02, 0x07};

// 1.2.840.113549.2.9

static const uint8_t kHMACWithSHA256[] = {0x2a, 0x86, 0x48, 0x86,

                                          0xf7, 0x0d, 0x02, 0x09};

static const struct {

  uint8_t oid[9];

  uint8_t oid_len;

  int nid;

  const EVP_CIPHER *(*cipher_func)();

} kCipherOIDs[] = {

    // 1.2.840.113549.3.2

    {{0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x03, 0x02},

     8,

     NID_rc2_cbc,

     &EVP_rc2_cbc},

    // 1.2.840.113549.3.7

    {{0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x03, 0x07},

     8,

     NID_des_ede3_cbc,

     &EVP_des_ede3_cbc},

    // 2.16.840.1.101.3.4.1.2

    {{0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x01, 0x02},

     9,

     NID_aes_128_cbc,

     &EVP_aes_128_cbc},

    // 2.16.840.1.101.3.4.1.22

    {{0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x01, 0x16},

     9,

     NID_aes_192_cbc,

     &EVP_aes_192_cbc},

    // 2.16.840.1.101.3.4.1.42

    {{0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x01, 0x2a},

     9,

     NID_aes_256_cbc,

     &EVP_aes_256_cbc},

};

static const EVP_CIPHER *cbs_to_cipher(const CBS *cbs) {

  for (const auto &cipher : kCipherOIDs) {

    if (CBS_mem_equal(cbs, cipher.oid, cipher.oid_len)) {

      return cipher.cipher_func();

    }

  }

  return nullptr;

}

static int add_cipher_oid(CBB *out, int nid) {

  for (const auto &cipher : kCipherOIDs) {

    if (cipher.nid == nid) {

      return CBB_add_asn1_element(out, CBS_ASN1_OBJECT, cipher.oid,

                                  cipher.oid_len);

    }

  }

  OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_UNSUPPORTED_CIPHER);

  return 0;

}

const EVP_CIPHER *bssl::pkcs5_pbe2_nid_to_cipher(int nid) {

  for (const auto &cipher : kCipherOIDs) {

    if (cipher.nid == nid) {

      return cipher.cipher_func();

    }

  }

  return nullptr;

}

static int pkcs5_pbe2_cipher_init(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,

                                  const EVP_MD *pbkdf2_md, uint32_t iterations,

                                  const char *pass, size_t pass_len,

                                  const uint8_t *salt, size_t salt_len,

                                  const uint8_t *iv, size_t iv_len, int enc) {

  if (iv_len != EVP_CIPHER_iv_length(cipher)) {

    OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_ERROR_SETTING_CIPHER_PARAMS);

    return 0;

  }

  uint8_t key[EVP_MAX_KEY_LENGTH];

  int ret = PKCS5_PBKDF2_HMAC(pass, pass_len, salt, salt_len, iterations,

                              pbkdf2_md, EVP_CIPHER_key_length(cipher), key) &&

            EVP_CipherInit_ex(ctx, cipher, nullptr /* engine */, key, iv, enc);

  OPENSSL_cleanse(key, EVP_MAX_KEY_LENGTH);

  return ret;

}

int bssl::PKCS5_pbe2_encrypt_init(CBB *out, EVP_CIPHER_CTX *ctx,

                                  const EVP_CIPHER *cipher, uint32_t iterations,

                                  const char *pass, size_t pass_len,

                                  const uint8_t *salt, size_t salt_len) {

  int cipher_nid = EVP_CIPHER_nid(cipher);

  if (cipher_nid == NID_undef) {

    OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_CIPHER_HAS_NO_OBJECT_IDENTIFIER);

    return 0;

  }

  // Generate a random IV.

  uint8_t iv[EVP_MAX_IV_LENGTH];

  if (!RAND_bytes(iv, EVP_CIPHER_iv_length(cipher))) {

    return 0;

  }

  // See RFC 8018, appendix A.

  CBB algorithm, param, kdf, kdf_param, prf, cipher_cbb;

  if (!CBB_add_asn1(out, &algorithm, CBS_ASN1_SEQUENCE) ||

      !CBB_add_asn1_element(&algorithm, CBS_ASN1_OBJECT, kPBES2,

                            sizeof(kPBES2)) ||

      !CBB_add_asn1(&algorithm, &param, CBS_ASN1_SEQUENCE) ||

      !CBB_add_asn1(&param, &kdf, CBS_ASN1_SEQUENCE) ||

      !CBB_add_asn1_element(&kdf, CBS_ASN1_OBJECT, kPBKDF2, sizeof(kPBKDF2)) ||

      !CBB_add_asn1(&kdf, &kdf_param, CBS_ASN1_SEQUENCE) ||

      !CBB_add_asn1_octet_string(&kdf_param, salt, salt_len) ||

      !CBB_add_asn1_uint64(&kdf_param, iterations) ||

      // Specify a key length for RC2.

      (cipher_nid == NID_rc2_cbc &&

       !CBB_add_asn1_uint64(&kdf_param, EVP_CIPHER_key_length(cipher))) ||

      // Use hmacWithSHA256 for the PRF.

      !CBB_add_asn1(&kdf_param, &prf, CBS_ASN1_SEQUENCE) ||

      !CBB_add_asn1_element(&prf, CBS_ASN1_OBJECT, kHMACWithSHA256,

                            sizeof(kHMACWithSHA256)) ||

      !CBB_add_asn1_element(&prf, CBS_ASN1_NULL, nullptr, 0) ||

      !CBB_add_asn1(&param, &cipher_cbb, CBS_ASN1_SEQUENCE) ||

      !add_cipher_oid(&cipher_cbb, cipher_nid) ||

      // RFC 8018 says RC2-CBC and RC5-CBC-Pad use a SEQUENCE with version and

      // IV, but OpenSSL always uses an OCTET STRING IV, so we do the same.

      !CBB_add_asn1_octet_string(&cipher_cbb, iv,

                                 EVP_CIPHER_iv_length(cipher)) ||

      !CBB_flush(out)) {

    return 0;

  }

  return pkcs5_pbe2_cipher_init(ctx, cipher, EVP_sha256(), iterations, pass,

                                pass_len, salt, salt_len, iv,

                                EVP_CIPHER_iv_length(cipher), 1 /* encrypt */);

}

int bssl::PKCS5_pbe2_decrypt_init(const struct pbe_suite *suite,

                                  EVP_CIPHER_CTX *ctx, const char *pass,

                                  size_t pass_len, CBS *param) {

  CBS pbe_param, kdf, kdf_obj, enc_scheme, enc_obj;

  if (!CBS_get_asn1(param, &pbe_param, CBS_ASN1_SEQUENCE) ||

      CBS_len(param) != 0 ||

      !CBS_get_asn1(&pbe_param, &kdf, CBS_ASN1_SEQUENCE) ||

      !CBS_get_asn1(&pbe_param, &enc_scheme, CBS_ASN1_SEQUENCE) ||

      CBS_len(&pbe_param) != 0 ||

      !CBS_get_asn1(&kdf, &kdf_obj, CBS_ASN1_OBJECT) ||

      !CBS_get_asn1(&enc_scheme, &enc_obj, CBS_ASN1_OBJECT)) {

    OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_DECODE_ERROR);

    return 0;

  }

  // Only PBKDF2 is supported.

  if (!CBS_mem_equal(&kdf_obj, kPBKDF2, sizeof(kPBKDF2))) {

    OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_UNSUPPORTED_KEY_DERIVATION_FUNCTION);

    return 0;

  }

  // See if we recognise the encryption algorithm.

  const EVP_CIPHER *cipher = cbs_to_cipher(&enc_obj);

  if (cipher == nullptr) {

    OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_UNSUPPORTED_CIPHER);

    return 0;

  }

  // Parse the KDF parameters. See RFC 8018, appendix A.2.

  CBS pbkdf2_params, salt;

  uint64_t iterations;

  if (!CBS_get_asn1(&kdf, &pbkdf2_params, CBS_ASN1_SEQUENCE) ||

      CBS_len(&kdf) != 0 ||

      !CBS_get_asn1(&pbkdf2_params, &salt, CBS_ASN1_OCTETSTRING) ||

      !CBS_get_asn1_uint64(&pbkdf2_params, &iterations)) {

    OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_DECODE_ERROR);

    return 0;

  }

  if (!pkcs12_iterations_acceptable(iterations)) {

    OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_ITERATION_COUNT);

    return 0;

  }

  // The optional keyLength parameter, if present, must match the key length of

  // the cipher.

  if (CBS_peek_asn1_tag(&pbkdf2_params, CBS_ASN1_INTEGER)) {

    uint64_t key_len;

    if (!CBS_get_asn1_uint64(&pbkdf2_params, &key_len)) {

      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_DECODE_ERROR);

      return 0;

    }

    if (key_len != EVP_CIPHER_key_length(cipher)) {

      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_UNSUPPORTED_KEYLENGTH);

      return 0;

    }

  }

  const EVP_MD *md = EVP_sha1();

  if (CBS_len(&pbkdf2_params) != 0) {

    CBS alg_id, prf;

    if (!CBS_get_asn1(&pbkdf2_params, &alg_id, CBS_ASN1_SEQUENCE) ||

        !CBS_get_asn1(&alg_id, &prf, CBS_ASN1_OBJECT) ||

        CBS_len(&pbkdf2_params) != 0) {

      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_DECODE_ERROR);

      return 0;

    }

    if (CBS_mem_equal(&prf, kHMACWithSHA1, sizeof(kHMACWithSHA1))) {

      // hmacWithSHA1 is the DEFAULT, so DER requires it be omitted, but we

      // match OpenSSL in tolerating it being present.

      md = EVP_sha1();

    } else if (CBS_mem_equal(&prf, kHMACWithSHA256, sizeof(kHMACWithSHA256))) {

      md = EVP_sha256();

    } else {

      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_UNSUPPORTED_PRF);

      return 0;

    }

    // All supported PRFs use a NULL parameter.

    CBS null;

    if (!CBS_get_asn1(&alg_id, &null, CBS_ASN1_NULL) ||

        CBS_len(&null) != 0 ||

        CBS_len(&alg_id) != 0) {

      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_DECODE_ERROR);

      return 0;

    }

  }

  // Parse the encryption scheme parameters. Note OpenSSL does not match the

  // specification. Per RFC 8018, this should depend on the encryption scheme.

  // In particular, RC2-CBC uses a SEQUENCE with version and IV. We align with

  // OpenSSL.

  CBS iv;

  if (!CBS_get_asn1(&enc_scheme, &iv, CBS_ASN1_OCTETSTRING) ||

      CBS_len(&enc_scheme) != 0) {

    OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_UNSUPPORTED_PRF);

    return 0;

  }

  return pkcs5_pbe2_cipher_init(ctx, cipher, md, (uint32_t)iterations, pass,

                                pass_len, CBS_data(&salt), CBS_len(&salt),

                                CBS_data(&iv), CBS_len(&iv), 0 /* decrypt */);

}