/src/gnutls/lib/x509/privkey_pkcs8.c

Source (jump to first uncovered line)
/*
 * Copyright (C) 2003-2016 Free Software Foundation, Inc.
 * Copyright (C) 2014-2017 Red Hat
 * Copyright (C) 2014-2016 Nikos Mavrogiannopoulos
 *
 * Author: Nikos Mavrogiannopoulos
 *
 * This file is part of GnuTLS.
 *
 * The GnuTLS is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>
 *
 */

#include "gnutls_int.h"

#include "datum.h"
#include "global.h"
#include "errors.h"
#include "common.h"
#include "x509.h"
#include "x509_b64.h"
#include "x509_int.h"
#include "pkcs7_int.h"
#include "algorithms.h"
#include "num.h"
#include "random.h"
#include "pk.h"
#include "attributes.h"
#include "prov-seed.h"

static int _decode_pkcs8_ecc_key(asn1_node pkcs8_asn,
         gnutls_x509_privkey_t pkey);
static int pkcs8_key_info(const gnutls_datum_t *raw_key,
        const struct pkcs_cipher_schema_st **p,
        struct pbkdf2_params *kdf_params, char **oid);

static int decode_private_key_info(const gnutls_datum_t *der,
           gnutls_x509_privkey_t pkey);

#define PEM_PKCS8 "ENCRYPTED PRIVATE KEY"
#define PEM_UNENCRYPTED_PKCS8 "PRIVATE KEY"

typedef enum ml_dsa_privkey_format_flags_t {
  ML_DSA_PRIVKEY_FORMAT_NONE = 0,
  ML_DSA_PRIVKEY_FORMAT_SEED = 1 << 0,
  ML_DSA_PRIVKEY_FORMAT_EXPANDED = 1 << 1,
  ML_DSA_PRIVKEY_FORMAT_BOTH = ML_DSA_PRIVKEY_FORMAT_SEED |
             ML_DSA_PRIVKEY_FORMAT_EXPANDED,
} ml_dsa_privkey_format_flags_t;

static inline ml_dsa_privkey_format_flags_t
flags_to_ml_dsa_privkey_format(gnutls_pkcs_encrypt_flags_t flags)
{
  ml_dsa_privkey_format_flags_t format = ML_DSA_PRIVKEY_FORMAT_NONE;

  if (flags & GNUTLS_PKCS_MLDSA_SEED)
    format |= ML_DSA_PRIVKEY_FORMAT_SEED;
  if (flags & GNUTLS_PKCS_MLDSA_EXPANDED)
    format |= ML_DSA_PRIVKEY_FORMAT_EXPANDED;

  return format;
}

static int encode_ml_dsa_inner_private_key(const gnutls_x509_privkey_t pkey,
             gnutls_datum_t *raw_key,
             ml_dsa_privkey_format_flags_t format)
{
  int ret = 0;
  asn1_node inner_asn = NULL;

  /* The default is the "both" format if seed is available;
   * otherwise, "expanded" */
  if (format == ML_DSA_PRIVKEY_FORMAT_NONE) {
    format = pkey->params.raw_seed.data ?
         ML_DSA_PRIVKEY_FORMAT_BOTH :
         ML_DSA_PRIVKEY_FORMAT_EXPANDED;
  }

  /* libtasn1 doesn't support encoding instructions in CHOICE,
   * format it manually */
  if (format == ML_DSA_PRIVKEY_FORMAT_SEED) {
    raw_key->data = gnutls_malloc(34);
    if (!raw_key->data)
      return GNUTLS_E_MEMORY_ERROR;

    raw_key->data[0] = 0x80;
    raw_key->data[1] = 0x20;
    memcpy(&raw_key->data[2], pkey->params.raw_seed.data, 32);
    raw_key->size = 34;
  } else {
    int result;

    result = asn1_create_element(_gnutls_get_gnutls_asn(),
               "GNUTLS.MLDSAInnerPrivateKey",
               &inner_asn);
    if (result != ASN1_SUCCESS)
      return gnutls_assert_val(_gnutls_asn2err(result));

    switch (format) {
    case ML_DSA_PRIVKEY_FORMAT_EXPANDED:
      result = asn1_write_value(inner_asn, "", "expandedKey",
              1);
      if (result != ASN1_SUCCESS) {
        gnutls_assert();
        ret = _gnutls_asn2err(result);
        goto cleanup;
      }
      result = asn1_write_value(inner_asn, "expandedKey",
              pkey->params.raw_priv.data,
              pkey->params.raw_priv.size);
      if (result != ASN1_SUCCESS) {
        gnutls_assert();
        ret = _gnutls_asn2err(result);
        goto cleanup;
      }
      break;
    case ML_DSA_PRIVKEY_FORMAT_BOTH:
      result = asn1_write_value(inner_asn, "", "both", 1);
      if (result != ASN1_SUCCESS) {
        gnutls_assert();
        ret = _gnutls_asn2err(result);
        goto cleanup;
      }
      result = asn1_write_value(inner_asn, "both.seed",
              pkey->params.raw_seed.data,
              pkey->params.raw_seed.size);
      if (result != ASN1_SUCCESS) {
        gnutls_assert();
        ret = _gnutls_asn2err(result);
        goto cleanup;
      }
      result = asn1_write_value(inner_asn, "both.expandedKey",
              pkey->params.raw_priv.data,
              pkey->params.raw_priv.size);
      if (result != ASN1_SUCCESS) {
        gnutls_assert();
        ret = _gnutls_asn2err(result);
        goto cleanup;
      }
      break;
    default:
      ret = gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
      goto cleanup;
    }

    ret = _gnutls_x509_der_encode(inner_asn, "", raw_key, 0);
    if (ret < 0) {
      gnutls_assert();
      goto cleanup;
    }
  }

cleanup:
  asn1_delete_structure2(&inner_asn, ASN1_DELETE_FLAG_ZEROIZE);
  return ret;
}

/* Returns a negative error code if the encryption schema in
 * the OID is not supported. The schema ID is returned.
 */
/* Encodes a private key to the raw format PKCS #8 needs.
 * For RSA it is a PKCS #1 DER private key and for DSA it is
 * an ASN.1 INTEGER of the x value.
 */
inline static int _encode_privkey(gnutls_x509_privkey_t pkey,
          gnutls_datum_t *raw,
          gnutls_pkcs_encrypt_flags_t flags)
{
  int ret;
  asn1_node spk = NULL;

  switch (pkey->params.algo) {
  case GNUTLS_PK_EDDSA_ED25519:
  case GNUTLS_PK_EDDSA_ED448:
  case GNUTLS_PK_ECDH_X25519:
  case GNUTLS_PK_ECDH_X448:
    /* we encode as octet string (which is going to be stored inside
     * another octet string). No comments. */
    ret = _gnutls_x509_encode_string(ASN1_ETYPE_OCTET_STRING,
             pkey->params.raw_priv.data,
             pkey->params.raw_priv.size,
             raw);
    if (ret < 0)
      gnutls_assert();
    return ret;
  case GNUTLS_PK_MLDSA44:
  case GNUTLS_PK_MLDSA65:
  case GNUTLS_PK_MLDSA87:
    ret = encode_ml_dsa_inner_private_key(
      pkey, raw, flags_to_ml_dsa_privkey_format(flags));
    if (ret < 0)
      gnutls_assert();
    break;
  case GNUTLS_PK_GOST_01:
  case GNUTLS_PK_GOST_12_256:
  case GNUTLS_PK_GOST_12_512:
    if ((ret = asn1_create_element(_gnutls_get_gnutls_asn(),
                 "GNUTLS.GOSTPrivateKey",
                 &spk)) != ASN1_SUCCESS) {
      gnutls_assert();
      ret = _gnutls_asn2err(ret);
      goto error;
    }

    ret = _gnutls_x509_write_key_int_le(
      spk, "", pkey->params.params[GOST_K]);
    if (ret < 0) {
      gnutls_assert();
      goto error;
    }

    ret = _gnutls_x509_der_encode(spk, "", raw, 0);
    if (ret < 0) {
      gnutls_assert();
      goto error;
    }

    asn1_delete_structure2(&spk, ASN1_DELETE_FLAG_ZEROIZE);
    break;

  case GNUTLS_PK_RSA:
  case GNUTLS_PK_RSA_PSS:
  case GNUTLS_PK_RSA_OAEP:
  case GNUTLS_PK_ECDSA:
    ret = _gnutls_x509_export_int2(pkey->key, GNUTLS_X509_FMT_DER,
                 "", raw);
    if (ret < 0) {
      gnutls_assert();
      goto error;
    }

    break;
  case GNUTLS_PK_DSA:
    /* DSAPublicKey == INTEGER */
    if ((ret = asn1_create_element(_gnutls_get_gnutls_asn(),
                 "GNUTLS.DSAPublicKey", &spk)) !=
        ASN1_SUCCESS) {
      gnutls_assert();
      return _gnutls_asn2err(ret);
    }

    ret = _gnutls_x509_write_int(spk, "", pkey->params.params[4],
               1);
    if (ret < 0) {
      gnutls_assert();
      goto error;
    }
    ret = _gnutls_x509_der_encode(spk, "", raw, 0);
    if (ret < 0) {
      gnutls_assert();
      goto error;
    }

    asn1_delete_structure2(&spk, ASN1_DELETE_FLAG_ZEROIZE);
    break;

  default:
    gnutls_assert();
    return GNUTLS_E_INVALID_REQUEST;
  }

  return 0;

error:
  asn1_delete_structure2(&spk, ASN1_DELETE_FLAG_ZEROIZE);
  asn1_delete_structure(&spk);
  return ret;
}

/* 
 * Encodes a PKCS #1 private key to a PKCS #8 private key
 * info. The output will be allocated and stored into der. Also
 * the asn1_node of private key info will be returned.
 */
static int encode_to_private_key_info(gnutls_x509_privkey_t pkey,
              gnutls_datum_t *der, asn1_node *pkey_info,
              gnutls_pkcs_encrypt_flags_t flags)
{
  int result, len;
  uint8_t null = 0;
  const char *oid;
  gnutls_datum_t algo_params = { NULL, 0 };
  gnutls_datum_t algo_privkey = { NULL, 0 };

  oid = gnutls_pk_get_oid(pkey->params.algo);
  if (oid == NULL) {
    gnutls_assert();
    return GNUTLS_E_UNIMPLEMENTED_FEATURE;
  }

  result = _gnutls_x509_write_pubkey_params(&pkey->params, &algo_params);
  if (result < 0) {
    gnutls_assert();
    return result;
  }

  if ((result = asn1_create_element(_gnutls_get_pkix(),
            "PKIX1.pkcs-8-PrivateKeyInfo",
            pkey_info)) != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }

  /* Write the version.
   */
  result = asn1_write_value(*pkey_info, "version", &null, 1);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }

  /* write the privateKeyAlgorithm
   * fields. (OID+NULL data)
   */
  result = asn1_write_value(*pkey_info, "privateKeyAlgorithm.algorithm",
          oid, 1);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }

  result = asn1_write_value(*pkey_info, "privateKeyAlgorithm.parameters",
          algo_params.data, algo_params.size);
  _gnutls_free_key_datum(&algo_params);

  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }

  /* Write the raw private key
   */
  result = _encode_privkey(pkey, &algo_privkey, flags);
  if (result < 0) {
    gnutls_assert();
    goto error;
  }

  result = asn1_write_value(*pkey_info, "privateKey", algo_privkey.data,
          algo_privkey.size);
  _gnutls_free_key_datum(&algo_privkey);

  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }

  if ((pkey->params.pkflags & GNUTLS_PK_FLAG_PROVABLE) &&
      pkey->params.seed_size > 0) {
    gnutls_datum_t seed_info;
    /* rfc8479 attribute encoding */

    result = _x509_encode_provable_seed(pkey, &seed_info);
    if (result < 0) {
      gnutls_assert();
      goto error;
    }

    result = _x509_set_attribute(*pkey_info, "attributes",
               OID_ATTR_PROV_SEED, &seed_info);
    gnutls_free(seed_info.data);
    if (result < 0) {
      gnutls_assert();
      goto error;
    }
  } else {
    /* Append an empty attributes field.
     */
    result = asn1_write_value(*pkey_info, "attributes", NULL, 0);
    if (result != ASN1_SUCCESS) {
      gnutls_assert();
      result = _gnutls_asn2err(result);
      goto error;
    }
  }

  /* Append an empty publicKey field.
   */
  result = asn1_write_value(*pkey_info, "publicKey", NULL, 0);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }

  /* DER Encode the generated private key info.
   */
  len = 0;
  result = asn1_der_coding(*pkey_info, "", NULL, &len, NULL);
  if (result != ASN1_MEM_ERROR) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }

  /* allocate data for the der
   */
  der->size = len;
  der->data = gnutls_malloc(len);
  if (der->data == NULL) {
    gnutls_assert();
    return GNUTLS_E_MEMORY_ERROR;
  }

  result = asn1_der_coding(*pkey_info, "", der->data, &len, NULL);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }

  return 0;

error:
  asn1_delete_structure2(pkey_info, ASN1_DELETE_FLAG_ZEROIZE);
  _gnutls_free_datum(&algo_params);
  _gnutls_free_key_datum(&algo_privkey);
  return result;
}

/* Converts a PKCS #8 private key info to
 * a PKCS #8 EncryptedPrivateKeyInfo.
 */
static int encode_to_pkcs8_key(schema_id schema, const gnutls_datum_t *der_key,
             const char *password, asn1_node *out)
{
  int result;
  gnutls_datum_t key = { NULL, 0 };
  gnutls_datum_t tmp = { NULL, 0 };
  asn1_node pkcs8_asn = NULL;
  struct pbkdf2_params kdf_params;
  struct pbe_enc_params enc_params;
  const struct pkcs_cipher_schema_st *s;

  s = _gnutls_pkcs_schema_get(schema);
  if (s == NULL || s->decrypt_only) {
    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
  }

  if ((result = asn1_create_element(
         _gnutls_get_pkix(), "PKIX1.pkcs-8-EncryptedPrivateKeyInfo",
         &pkcs8_asn)) != ASN1_SUCCESS) {
    gnutls_assert();
    return _gnutls_asn2err(result);
  }

  /* Write the encryption schema OID
   */
  result = asn1_write_value(pkcs8_asn, "encryptionAlgorithm.algorithm",
          s->write_oid, 1);

  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }

  /* Generate a symmetric key.
   */

  result = _gnutls_pkcs_generate_key(schema, password, &kdf_params,
             &enc_params, &key);
  if (result < 0) {
    gnutls_assert();
    goto error;
  }

  result = _gnutls_pkcs_write_schema_params(
    schema, pkcs8_asn, "encryptionAlgorithm.parameters",
    &kdf_params, &enc_params);
  if (result < 0) {
    gnutls_assert();
    goto error;
  }

  /* Parameters have been encoded. Now
   * encrypt the Data.
   */
  result =
    _gnutls_pkcs_raw_encrypt_data(der_key, &enc_params, &key, &tmp);
  if (result < 0) {
    gnutls_assert();
    goto error;
  }

  /* write the encrypted data.
   */
  result = asn1_write_value(pkcs8_asn, "encryptedData", tmp.data,
          tmp.size);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }

  _gnutls_free_datum(&tmp);
  _gnutls_free_key_datum(&key);

  *out = pkcs8_asn;

  return 0;

error:
  _gnutls_free_key_datum(&key);
  _gnutls_free_datum(&tmp);
  asn1_delete_structure2(&pkcs8_asn, ASN1_DELETE_FLAG_ZEROIZE);
  return result;
}

/**
 * gnutls_x509_privkey_export_pkcs8:
 * @key: Holds the key
 * @format: the format of output params. One of PEM or DER.
 * @password: the password that will be used to encrypt the key.
 * @flags: an ORed sequence of gnutls_pkcs_encrypt_flags_t
 * @output_data: will contain a private key PEM or DER encoded
 * @output_data_size: holds the size of output_data (and will be
 *   replaced by the actual size of parameters)
 *
 * This function will export the private key to a PKCS8 structure.
 * Both RSA and DSA keys can be exported. For DSA keys we use
 * PKCS #11 definitions. If the flags do not specify the encryption
 * cipher, then the default 3DES (PBES2) will be used.
 *
 * The @password can be either ASCII or UTF-8 in the default PBES2
 * encryption schemas, or ASCII for the PKCS12 schemas.
 *
 * If the buffer provided is not long enough to hold the output, then
 * *output_data_size is updated and GNUTLS_E_SHORT_MEMORY_BUFFER will
 * be returned.
 *
 * If the structure is PEM encoded, it will have a header
 * of "BEGIN ENCRYPTED PRIVATE KEY" or "BEGIN PRIVATE KEY" if
 * encryption is not used.
 *
 * Returns: In case of failure a negative error code will be
 *   returned, and 0 on success.
 **/
int gnutls_x509_privkey_export_pkcs8(gnutls_x509_privkey_t key,
             gnutls_x509_crt_fmt_t format,
             const char *password, unsigned int flags,
             void *output_data,
             size_t *output_data_size)
{
  asn1_node pkcs8_asn = NULL, pkey_info;
  int ret;
  gnutls_datum_t tmp = { NULL, 0 };
  schema_id schema;

  if (key == NULL) {
    gnutls_assert();
    return GNUTLS_E_INVALID_REQUEST;
  }

  /* Get the private key info
   * tmp holds the DER encoding.
   */
  ret = encode_to_private_key_info(key, &tmp, &pkey_info, flags);
  if (ret < 0) {
    gnutls_assert();
    return ret;
  }

  schema = _gnutls_pkcs_flags_to_schema(flags);

  if (((flags & GNUTLS_PKCS_PLAIN) || password == NULL) &&
      !(flags & GNUTLS_PKCS_NULL_PASSWORD)) {
    _gnutls_free_datum(&tmp);

    ret = _gnutls_x509_export_int(pkey_info, format,
                PEM_UNENCRYPTED_PKCS8,
                output_data, output_data_size);

    asn1_delete_structure2(&pkey_info, ASN1_DELETE_FLAG_ZEROIZE);
  } else {
    asn1_delete_structure2(
      &pkey_info,
      ASN1_DELETE_FLAG_ZEROIZE); /* we don't need it */

    ret = encode_to_pkcs8_key(schema, &tmp, password, &pkcs8_asn);
    _gnutls_free_key_datum(&tmp);

    if (ret < 0) {
      gnutls_assert();
      return ret;
    }

    ret = _gnutls_x509_export_int(pkcs8_asn, format, PEM_PKCS8,
                output_data, output_data_size);

    asn1_delete_structure2(&pkcs8_asn, ASN1_DELETE_FLAG_ZEROIZE);
  }

  return ret;
}

/**
 * gnutls_pkcs8_info:
 * @data: Holds the PKCS #8 data
 * @format: the format of the PKCS #8 data
 * @schema: indicate the schema as one of %gnutls_pkcs_encrypt_flags_t
 * @cipher: the cipher used as %gnutls_cipher_algorithm_t
 * @salt: PBKDF2 salt (if non-NULL then @salt_size initially holds its size)
 * @salt_size: PBKDF2 salt size
 * @iter_count: PBKDF2 iteration count
 * @oid: if non-NULL it will contain an allocated null-terminated variable with the OID
 *
 * This function will provide information on the algorithms used
 * in a particular PKCS #8 structure. If the structure algorithms
 * are unknown the code %GNUTLS_E_UNKNOWN_CIPHER_TYPE will be returned,
 * and only @oid, will be set. That is, @oid will be set on encrypted PKCS #8
 * structures whether supported or not. It must be deinitialized using gnutls_free().
 * The other variables are only set on supported structures.
 *
 * Returns: %GNUTLS_E_INVALID_REQUEST if the provided structure isn't an encrypted key,
 *  %GNUTLS_E_UNKNOWN_CIPHER_TYPE if the structure's encryption isn't supported, or
 *  another negative error code in case of a failure. Zero on success.
 *
 * Since: 3.4.0
 **/
int gnutls_pkcs8_info(const gnutls_datum_t *data, gnutls_x509_crt_fmt_t format,
          unsigned int *schema, unsigned int *cipher, void *salt,
          unsigned int *salt_size, unsigned int *iter_count,
          char **oid)
{
  int ret = 0, need_free = 0;
  gnutls_datum_t _data;
  const struct pkcs_cipher_schema_st *p = NULL;
  struct pbkdf2_params kdf;

  memset(&kdf, 0, sizeof(kdf));

  if (oid)
    *oid = NULL;

  _data.data = data->data;
  _data.size = data->size;

  /* If the Certificate is in PEM format then decode it
   */
  if (format == GNUTLS_X509_FMT_PEM) {
    /* Try the first header 
     */
    ret = _gnutls_fbase64_decode(PEM_UNENCRYPTED_PKCS8, data->data,
               data->size, &_data);

    if (ret < 0) { /* Try the encrypted header 
         */
      ret = _gnutls_fbase64_decode(PEM_PKCS8, data->data,
                 data->size, &_data);

      if (ret < 0) {
        gnutls_assert();
        return ret;
      }
    }

    need_free = 1;
  }

  ret = pkcs8_key_info(&_data, &p, &kdf, oid);
  if (ret == GNUTLS_E_DECRYPTION_FAILED)
    ret = GNUTLS_E_INVALID_REQUEST;
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  assert(p != NULL);

  if (need_free)
    _gnutls_free_datum(&_data);

  if (schema)
    *schema = p->flag;

  if (cipher)
    *cipher = p->cipher;

  if (iter_count)
    *iter_count = kdf.iter_count;

  if (salt) {
    if (*salt_size >= (unsigned)kdf.salt_size) {
      memcpy(salt, kdf.salt, kdf.salt_size);
    } else {
      *salt_size = kdf.salt_size;
      ret = gnutls_assert_val(GNUTLS_E_SHORT_MEMORY_BUFFER);
      goto cleanup;
    }
  }

  if (salt_size)
    *salt_size = kdf.salt_size;

  return 0;

cleanup:
  if (ret != GNUTLS_E_UNKNOWN_CIPHER_TYPE && oid) {
    gnutls_free(*oid);
  }
  if (need_free)
    _gnutls_free_datum(&_data);
  return ret;
}

/**
 * gnutls_x509_privkey_export2_pkcs8:
 * @key: Holds the key
 * @format: the format of output params. One of PEM or DER.
 * @password: the password that will be used to encrypt the key.
 * @flags: an ORed sequence of gnutls_pkcs_encrypt_flags_t
 * @out: will contain a private key PEM or DER encoded
 *
 * This function will export the private key to a PKCS8 structure.
 * Both RSA and DSA keys can be exported. For DSA keys we use
 * PKCS #11 definitions. If the flags do not specify the encryption
 * cipher, then the default 3DES (PBES2) will be used.
 *
 * The @password can be either ASCII or UTF-8 in the default PBES2
 * encryption schemas, or ASCII for the PKCS12 schemas.
 *
 * The output buffer is allocated using gnutls_malloc().
 *
 * If the structure is PEM encoded, it will have a header
 * of "BEGIN ENCRYPTED PRIVATE KEY" or "BEGIN PRIVATE KEY" if
 * encryption is not used.
 *
 * Returns: In case of failure a negative error code will be
 *   returned, and 0 on success.
 *
 * Since 3.1.3
 **/
int gnutls_x509_privkey_export2_pkcs8(gnutls_x509_privkey_t key,
              gnutls_x509_crt_fmt_t format,
              const char *password, unsigned int flags,
              gnutls_datum_t *out)
{
  asn1_node pkcs8_asn = NULL, pkey_info;
  int ret;
  gnutls_datum_t tmp = { NULL, 0 };
  schema_id schema;

  if (key == NULL) {
    gnutls_assert();
    return GNUTLS_E_INVALID_REQUEST;
  }

  /* Get the private key info
   * tmp holds the DER encoding.
   */
  ret = encode_to_private_key_info(key, &tmp, &pkey_info, flags);
  if (ret < 0) {
    gnutls_assert();
    return ret;
  }

  schema = _gnutls_pkcs_flags_to_schema(flags);

  if (((flags & GNUTLS_PKCS_PLAIN) || password == NULL) &&
      !(flags & GNUTLS_PKCS_NULL_PASSWORD)) {
    _gnutls_free_key_datum(&tmp);

    ret = _gnutls_x509_export_int2(pkey_info, format,
                 PEM_UNENCRYPTED_PKCS8, out);

    asn1_delete_structure2(&pkey_info, ASN1_DELETE_FLAG_ZEROIZE);
  } else {
    asn1_delete_structure2(
      &pkey_info,
      ASN1_DELETE_FLAG_ZEROIZE); /* we don't need it */

    ret = encode_to_pkcs8_key(schema, &tmp, password, &pkcs8_asn);
    _gnutls_free_key_datum(&tmp);

    if (ret < 0) {
      gnutls_assert();
      return ret;
    }

    ret = _gnutls_x509_export_int2(pkcs8_asn, format, PEM_PKCS8,
                 out);

    asn1_delete_structure2(&pkcs8_asn, ASN1_DELETE_FLAG_ZEROIZE);
  }

  return ret;
}

/* We've gotten this far. In the real world it's almost certain
   * that we're dealing with a good file, but wrong password.
   * Sadly like 90% of random data is somehow valid DER for the
   * a first small number of bytes, so no easy way to guarantee. */
#define CHECK_ERR_FOR_ENCRYPTED(result)                     \
  if (result == GNUTLS_E_ASN1_ELEMENT_NOT_FOUND ||    \
      result == GNUTLS_E_ASN1_IDENTIFIER_NOT_FOUND || \
      result == GNUTLS_E_ASN1_DER_ERROR ||            \
      result == GNUTLS_E_ASN1_VALUE_NOT_FOUND ||      \
      result == GNUTLS_E_ASN1_GENERIC_ERROR ||        \
      result == GNUTLS_E_ASN1_VALUE_NOT_VALID ||      \
      result == GNUTLS_E_ASN1_TAG_ERROR ||            \
      result == GNUTLS_E_ASN1_TAG_IMPLICIT ||         \
      result == GNUTLS_E_ASN1_TYPE_ANY_ERROR ||       \
      result == GNUTLS_E_ASN1_SYNTAX_ERROR ||         \
      result == GNUTLS_E_ASN1_DER_OVERFLOW) {         \
    result = GNUTLS_E_DECRYPTION_FAILED;        \
  }

static int pkcs8_key_decrypt(const gnutls_datum_t *raw_key, asn1_node pkcs8_asn,
           const char *password, gnutls_x509_privkey_t pkey)
{
  int result, len;
  char enc_oid[MAX_OID_SIZE];
  gnutls_datum_t tmp = { NULL, 0 };
  int params_start, params_end, params_len;
  struct pbkdf2_params kdf_params;
  struct pbe_enc_params enc_params;
  schema_id schema;

  /* Check the encryption schema OID
   */
  len = sizeof(enc_oid);
  result = asn1_read_value(pkcs8_asn, "encryptionAlgorithm.algorithm",
         enc_oid, &len);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    goto error;
  }

  if ((result = _gnutls_check_pkcs_cipher_schema(enc_oid)) < 0) {
    gnutls_assert();
    goto error;
  }

  schema = result;

  /* Get the DER encoding of the parameters.
   */
  result = asn1_der_decoding_startEnd(pkcs8_asn, raw_key->data,
              raw_key->size,
              "encryptionAlgorithm.parameters",
              &params_start, &params_end);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }
  params_len = params_end - params_start + 1;

  result = _gnutls_read_pkcs_schema_params(&schema, password,
             &raw_key->data[params_start],
             params_len, &kdf_params,
             &enc_params);

  if (result < 0) {
    gnutls_assert();
    goto error;
  }

  /* Parameters have been decoded. Now
   * decrypt the EncryptedData.
   */
  result = _gnutls_pkcs_raw_decrypt_data(schema, pkcs8_asn,
                 "encryptedData", password,
                 &kdf_params, &enc_params, &tmp);
  if (result < 0) {
    gnutls_assert();
    result = GNUTLS_E_DECRYPTION_FAILED;
    goto error;
  }

  result = decode_private_key_info(&tmp, pkey);
  _gnutls_free_key_datum(&tmp);

  CHECK_ERR_FOR_ENCRYPTED(result);
  if (result < 0) {
    gnutls_assert();
    goto error;
  }

  return 0;

error:
  return result;
}

static int check_for_decrypted(const gnutls_datum_t *der)
{
  int result;
  asn1_node pkcs8_asn = NULL;

  if ((result = asn1_create_element(_gnutls_get_pkix(),
            "PKIX1.pkcs-8-PrivateKeyInfo",
            &pkcs8_asn)) != ASN1_SUCCESS) {
    gnutls_assert();
    return _gnutls_asn2err(result);
  }

  result =
    _asn1_strict_der_decode(&pkcs8_asn, der->data, der->size, NULL);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }

  result = 0;
error:
  asn1_delete_structure2(&pkcs8_asn, ASN1_DELETE_FLAG_ZEROIZE);
  return result;
}

static int pkcs8_key_info(const gnutls_datum_t *raw_key,
        const struct pkcs_cipher_schema_st **p,
        struct pbkdf2_params *kdf_params, char **oid)
{
  int result, len;
  char enc_oid[MAX_OID_SIZE * 2];
  int params_start, params_end, params_len;
  struct pbe_enc_params enc_params;
  schema_id schema;
  asn1_node pkcs8_asn = NULL;

  memset(&enc_params, 0, sizeof(enc_params));

  result = check_for_decrypted(raw_key);
  if (result == 0)
    return GNUTLS_E_INVALID_REQUEST;

  if ((result = asn1_create_element(
         _gnutls_get_pkix(), "PKIX1.pkcs-8-EncryptedPrivateKeyInfo",
         &pkcs8_asn)) != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }

  result = _asn1_strict_der_decode(&pkcs8_asn, raw_key->data,
           raw_key->size, NULL);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }

  /* Check the encryption schema OID
   */
  len = sizeof(enc_oid);
  result = asn1_read_value(pkcs8_asn, "encryptionAlgorithm.algorithm",
         enc_oid, &len);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    goto error;
  }

  if (oid) {
    *oid = gnutls_strdup(enc_oid);
  }

  if ((result = _gnutls_check_pkcs_cipher_schema(enc_oid)) < 0) {
    gnutls_assert();
    goto error;
  }

  schema = result;

  /* Get the DER encoding of the parameters.
   */
  result = asn1_der_decoding_startEnd(pkcs8_asn, raw_key->data,
              raw_key->size,
              "encryptionAlgorithm.parameters",
              &params_start, &params_end);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }
  params_len = params_end - params_start + 1;

  result = _gnutls_read_pkcs_schema_params(&schema, NULL,
             &raw_key->data[params_start],
             params_len, kdf_params,
             &enc_params);

  if (result < 0) {
    gnutls_assert();
    if (oid && enc_params.pbes2_oid[0] != 0) {
      snprintf(enc_oid, sizeof(enc_oid), "%s/%s", *oid,
         enc_params.pbes2_oid);
      gnutls_free(*oid);
      *oid = gnutls_strdup(enc_oid);
    }
    goto error;
  }

  *p = _gnutls_pkcs_schema_get(schema);
  if (*p == NULL) {
    gnutls_assert();
    result = GNUTLS_E_UNKNOWN_CIPHER_TYPE;
    goto error;
  }

  result = 0;

error:
  asn1_delete_structure2(&pkcs8_asn, ASN1_DELETE_FLAG_ZEROIZE);
  return result;
}

/* Converts a PKCS #8 key to
 * an internal structure (gnutls_private_key)
 * (normally a PKCS #1 encoded RSA key)
 */
static int pkcs8_key_decode(const gnutls_datum_t *raw_key, const char *password,
          gnutls_x509_privkey_t pkey, unsigned int decrypt)
{
  int result;
  asn1_node pkcs8_asn = NULL;

  if ((result = asn1_create_element(
         _gnutls_get_pkix(), "PKIX1.pkcs-8-EncryptedPrivateKeyInfo",
         &pkcs8_asn)) != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }

  result = _asn1_strict_der_decode(&pkcs8_asn, raw_key->data,
           raw_key->size, NULL);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }

  if (decrypt)
    result = pkcs8_key_decrypt(raw_key, pkcs8_asn, password, pkey);
  else
    result = 0;

error:
  asn1_delete_structure2(&pkcs8_asn, ASN1_DELETE_FLAG_ZEROIZE);
  return result;
}

/* Decodes an RSA privateKey from a PKCS8 structure.
 */
static int _decode_pkcs8_rsa_key(asn1_node pkcs8_asn,
         gnutls_x509_privkey_t pkey)
{
  int ret;
  gnutls_datum_t tmp = { NULL, 0 };

  ret = _gnutls_x509_read_value(pkcs8_asn, "privateKey", &tmp);
  if (ret < 0) {
    gnutls_assert();
    goto error;
  }

  pkey->key = _gnutls_privkey_decode_pkcs1_rsa_key(&tmp, pkey);
  _gnutls_free_key_datum(&tmp);

  if (pkey->key == NULL) {
    ret = GNUTLS_E_PK_INVALID_PRIVKEY;
    gnutls_assert();
    goto error;
  }

  ret = 0;

error:
  return ret;
}

/* Decodes an RSA-PSS privateKey from a PKCS8 structure.
 */
static int _decode_pkcs8_rsa_pss_key(asn1_node pkcs8_asn,
             gnutls_x509_privkey_t pkey)
{
  int ret;
  gnutls_datum_t tmp = { NULL, 0 };
  gnutls_x509_spki_st params;

  memset(&params, 0, sizeof(params));

  ret = _gnutls_x509_read_value(pkcs8_asn,
              "privateKeyAlgorithm.parameters", &tmp);
  if (ret < 0) {
    if (ret == GNUTLS_E_ASN1_VALUE_NOT_FOUND ||
        ret == GNUTLS_E_ASN1_ELEMENT_NOT_FOUND)
      goto skip_params;

    gnutls_assert();
    goto error;
  }

  ret = _gnutls_x509_read_rsa_pss_params(tmp.data, tmp.size, &params);
  _gnutls_free_key_datum(&tmp);

  if (ret < 0) {
    gnutls_assert();
    goto error;
  }

skip_params:
  ret = _decode_pkcs8_rsa_key(pkcs8_asn, pkey);
  if (ret < 0) {
    gnutls_assert();
    goto error;
  }

  pkey->params.algo = GNUTLS_PK_RSA_PSS;
  ret = _gnutls_x509_spki_copy(&pkey->params.spki, &params);
  if (ret < 0) {
    gnutls_assert();
    goto error;
  }

  ret = 0;

error:
  return ret;
}

/* Decodes an RSA-OAEP privateKey from a PKCS8 structure.
 */
static int _decode_pkcs8_rsa_oaep_key(asn1_node pkcs8_asn,
              gnutls_x509_privkey_t pkey)
{
  int ret;
  gnutls_datum_t tmp = { NULL, 0 };
  gnutls_x509_spki_st params;

  memset(&params, 0, sizeof(params));

  ret = _gnutls_x509_read_value(pkcs8_asn,
              "privateKeyAlgorithm.parameters", &tmp);
  if (ret < 0) {
    if (ret == GNUTLS_E_ASN1_VALUE_NOT_FOUND ||
        ret == GNUTLS_E_ASN1_ELEMENT_NOT_FOUND)
      goto skip_params;

    gnutls_assert();
    goto error;
  }

  ret = _gnutls_x509_read_rsa_oaep_params(tmp.data, tmp.size, &params);
  _gnutls_free_key_datum(&tmp);

  if (ret < 0) {
    gnutls_assert();
    goto error;
  }

skip_params:
  ret = _decode_pkcs8_rsa_key(pkcs8_asn, pkey);
  if (ret < 0) {
    gnutls_assert();
    goto error;
  }

  pkey->params.algo = GNUTLS_PK_RSA_OAEP;
  /* Take ownership of allocated members of params */
  pkey->params.spki = params;

  ret = 0;

error:
  return ret;
}

/* Decodes an ECC privateKey from a PKCS8 structure.
 */
static int _decode_pkcs8_ecc_key(asn1_node pkcs8_asn,
         gnutls_x509_privkey_t pkey)
{
  int ret;
  gnutls_datum_t tmp = { NULL, 0 };
  unsigned char oid[MAX_OID_SIZE];
  unsigned curve = GNUTLS_ECC_CURVE_INVALID;
  int len, result;

  /* openssl PKCS #8 files with ECC keys place the curve in
   * privateKeyAlgorithm.parameters instead of the ECPrivateKey.parameters.
   */
  len = sizeof(oid);
  result = asn1_read_value(pkcs8_asn, "privateKeyAlgorithm.parameters",
         oid, &len);
  if (result == ASN1_SUCCESS) {
    ret = _gnutls_x509_read_ecc_params(oid, len, &curve);
    if (ret < 0) {
      _gnutls_debug_log("PKCS#8: unknown curve OID %s\n",
            oid);
      curve = GNUTLS_ECC_CURVE_INVALID;
    }
  }

  ret = _gnutls_x509_read_value(pkcs8_asn, "privateKey", &tmp);
  if (ret < 0) {
    gnutls_assert();
    goto error;
  }

  ret = _gnutls_privkey_decode_ecc_key(&pkey->key, &tmp, pkey, curve);
  _gnutls_free_key_datum(&tmp);

  if (ret < 0) {
    gnutls_assert();
    goto error;
  }

  ret = 0;

error:
  return ret;
}

static int _decode_pkcs8_eddsa_key(asn1_node pkcs8_asn,
           gnutls_x509_privkey_t pkey, const char *oid)
{
  int ret;
  gnutls_datum_t tmp;
  gnutls_ecc_curve_t curve = GNUTLS_ECC_CURVE_INVALID;
  const gnutls_ecc_curve_entry_st *ce;

  gnutls_pk_params_init(&pkey->params);

  curve = gnutls_oid_to_ecc_curve(oid);
  if (curve == GNUTLS_ECC_CURVE_INVALID) {
    _gnutls_debug_log("PKCS#8: unknown curve OID %s\n", oid);
    return gnutls_assert_val(GNUTLS_E_ECC_UNSUPPORTED_CURVE);
  }

  ce = _gnutls_ecc_curve_get_params(curve);
  if (_curve_is_eddsa(ce)) {
    ret = _gnutls_x509_read_string(pkcs8_asn, "privateKey", &tmp,
                 ASN1_ETYPE_OCTET_STRING, 1);
    if (ret < 0) {
      gnutls_assert();
      return gnutls_assert_val(ret);
    }

    if (tmp.size != ce->size) {
      gnutls_free(tmp.data);
      return gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
    }
    gnutls_free(pkey->params.raw_priv.data);
    switch (curve) {
    case GNUTLS_ECC_CURVE_ED25519:
      pkey->params.algo = GNUTLS_PK_EDDSA_ED25519;
      break;
    case GNUTLS_ECC_CURVE_ED448:
      pkey->params.algo = GNUTLS_PK_EDDSA_ED448;
      break;
    default:
      return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
    }
    pkey->params.raw_priv.data = tmp.data;
    pkey->params.raw_priv.size = tmp.size;
    pkey->params.curve = curve;

    tmp.data = NULL;
    return 0;
  } else {
    return gnutls_assert_val(GNUTLS_E_ECC_UNSUPPORTED_CURVE);
  }
}

static int _decode_pkcs8_modern_ecdh_key(asn1_node pkcs8_asn,
           gnutls_x509_privkey_t pkey,
           const char *oid)
{
  int ret;
  gnutls_datum_t tmp;
  gnutls_ecc_curve_t curve = GNUTLS_ECC_CURVE_INVALID;
  const gnutls_ecc_curve_entry_st *ce;

  gnutls_pk_params_init(&pkey->params);

  curve = gnutls_oid_to_ecc_curve(oid);
  if (curve == GNUTLS_ECC_CURVE_INVALID) {
    _gnutls_debug_log("PKCS#8: unknown curve OID %s\n", oid);
    return gnutls_assert_val(GNUTLS_E_ECC_UNSUPPORTED_CURVE);
  }

  ce = _gnutls_ecc_curve_get_params(curve);
  if (_curve_is_modern_ecdh(ce)) {
    ret = _gnutls_x509_read_string(pkcs8_asn, "privateKey", &tmp,
                 ASN1_ETYPE_OCTET_STRING, 1);
    if (ret < 0) {
      gnutls_assert();
      return gnutls_assert_val(ret);
    }

    if (tmp.size != ce->size) {
      gnutls_free(tmp.data);
      return gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
    }
    gnutls_free(pkey->params.raw_priv.data);
    switch (curve) {
    case GNUTLS_ECC_CURVE_X25519:
      pkey->params.algo = GNUTLS_PK_ECDH_X25519;
      break;
    case GNUTLS_ECC_CURVE_X448:
      pkey->params.algo = GNUTLS_PK_ECDH_X448;
      break;
    default:
      return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
    }
    pkey->params.raw_priv.data = tmp.data;
    pkey->params.raw_priv.size = tmp.size;
    pkey->params.curve = curve;

    tmp.data = NULL;
    return 0;
  } else {
    return gnutls_assert_val(GNUTLS_E_ECC_UNSUPPORTED_CURVE);
  }
}

/* Converts a GOST key to
 * an internal structure (gnutls_private_key)
 */
static int _privkey_decode_gost_key(const gnutls_datum_t *raw_key,
            gnutls_x509_privkey_t pkey)
{
  int ret;
  int ecc_size = gnutls_ecc_curve_get_size(pkey->params.curve);

  /* Just to be sure here */
  if (ecc_size <= 0) {
    gnutls_assert();
    ret = GNUTLS_E_ECC_UNSUPPORTED_CURVE;
    goto error;
  }

  /* Private key form described in R 50.1.112-2016.
   * Private key can come up as masked value concatenated with several masks.
   * each part is of ecc_size bytes. Key will be unmasked in pk_fixup */
  if (raw_key->size % ecc_size == 0) {
    ret = _gnutls_mpi_init_scan_le(&pkey->params.params[GOST_K],
                 raw_key->data, raw_key->size);
    if (ret < 0) {
      gnutls_assert();
      goto error;
    }
  } else if (raw_key->data[0] == ASN1_TAG_INTEGER) {
    asn1_node pkey_asn;

    /* Very old format: INTEGER packed in OCTET STRING */
    if ((ret = asn1_create_element(_gnutls_get_gnutls_asn(),
                 "GNUTLS.GOSTPrivateKeyOld",
                 &pkey_asn)) != ASN1_SUCCESS) {
      gnutls_assert();
      ret = _gnutls_asn2err(ret);
      goto error;
    }

    ret = _asn1_strict_der_decode(&pkey_asn, raw_key->data,
                raw_key->size, NULL);
    if (ret != ASN1_SUCCESS) {
      gnutls_assert();
      ret = _gnutls_asn2err(ret);
      asn1_delete_structure2(&pkey_asn,
                 ASN1_DELETE_FLAG_ZEROIZE);
      goto error;
    }

    ret = _gnutls_x509_read_key_int(pkey_asn, "",
            &pkey->params.params[GOST_K]);
    if (ret < 0) {
      gnutls_assert();
      asn1_delete_structure2(&pkey_asn,
                 ASN1_DELETE_FLAG_ZEROIZE);
      goto error;
    }
    asn1_delete_structure2(&pkey_asn, ASN1_DELETE_FLAG_ZEROIZE);
  } else if (raw_key->data[0] == ASN1_TAG_OCTET_STRING) {
    asn1_node pkey_asn;

    /* format: OCTET STRING packed in OCTET STRING */
    if ((ret = asn1_create_element(_gnutls_get_gnutls_asn(),
                 "GNUTLS.GOSTPrivateKey",
                 &pkey_asn)) != ASN1_SUCCESS) {
      gnutls_assert();
      ret = _gnutls_asn2err(ret);
      goto error;
    }

    ret = _asn1_strict_der_decode(&pkey_asn, raw_key->data,
                raw_key->size, NULL);
    if (ret != ASN1_SUCCESS) {
      gnutls_assert();
      ret = _gnutls_asn2err(ret);
      asn1_delete_structure2(&pkey_asn,
                 ASN1_DELETE_FLAG_ZEROIZE);
      goto error;
    }

    ret = _gnutls_x509_read_key_int_le(
      pkey_asn, "", &pkey->params.params[GOST_K]);
    if (ret < 0) {
      gnutls_assert();
      asn1_delete_structure2(&pkey_asn,
                 ASN1_DELETE_FLAG_ZEROIZE);
      goto error;
    }
    asn1_delete_structure2(&pkey_asn, ASN1_DELETE_FLAG_ZEROIZE);
  } else {
    gnutls_assert();
    ret = GNUTLS_E_PARSING_ERROR;
    goto error;
  }

  pkey->params.params_nr++;

  return 0;

error:
  return ret;
}

/* Decodes a GOST privateKey from a PKCS8 structure.
 */
static int _decode_pkcs8_gost_key(asn1_node pkcs8_asn,
          gnutls_x509_privkey_t pkey,
          gnutls_pk_algorithm_t algo)
{
  int ret;
  gnutls_datum_t tmp;
  unsigned char
    oid[3 *
        MAX_OID_SIZE]; /* GOST parameters can have 3 OIDs at most */
  int len, result;

  gnutls_pk_params_init(&pkey->params);

  len = sizeof(oid);
  result = asn1_read_value(pkcs8_asn, "privateKeyAlgorithm.parameters",
         oid, &len);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    ret = GNUTLS_E_PARSING_ERROR;
    goto error;
  } else {
    ret = _gnutls_x509_read_gost_params(oid, len, &pkey->params,
                algo);
    if (ret < 0) {
      gnutls_assert();
      goto error;
    }
  }

  /* Will be fixed later by pk_fixup */
  ret = _gnutls_mpi_init(&pkey->params.params[GOST_X]);
  if (ret < 0) {
    gnutls_assert();
    goto error;
  }
  pkey->params.params_nr++;

  ret = _gnutls_mpi_init(&pkey->params.params[GOST_Y]);
  if (ret < 0) {
    gnutls_assert();
    goto error;
  }
  pkey->params.params_nr++;

  _gnutls_mpi_set_ui(pkey->params.params[GOST_X], 0);
  _gnutls_mpi_set_ui(pkey->params.params[GOST_Y], 0);

  ret = _gnutls_x509_read_value(pkcs8_asn, "privateKey", &tmp);
  if (ret < 0) {
    gnutls_assert();
    goto error;
  }

  ret = _privkey_decode_gost_key(&tmp, pkey);
  _gnutls_free_key_datum(&tmp);

  if (ret < 0) {
    gnutls_assert();
    goto error;
  }

  pkey->params.algo = algo;

  return 0;

error:
  gnutls_pk_params_clear(&pkey->params);
  gnutls_pk_params_release(&pkey->params);

  return ret;
}

/* Decodes an DSA privateKey and params from a PKCS8 structure.
 */
static int _decode_pkcs8_dsa_key(asn1_node pkcs8_asn,
         gnutls_x509_privkey_t pkey)
{
  int ret;
  gnutls_datum_t tmp = { NULL, 0 };

  gnutls_pk_params_init(&pkey->params);

  ret = _gnutls_x509_read_value(pkcs8_asn, "privateKey", &tmp);
  if (ret < 0) {
    gnutls_assert();
    goto error;
  }

  ret = _gnutls_x509_read_der_int(tmp.data, tmp.size,
          &pkey->params.params[4]);
  _gnutls_free_key_datum(&tmp);

  if (ret < 0) {
    gnutls_assert();
    goto error;
  }

  ret = _gnutls_x509_read_value(pkcs8_asn,
              "privateKeyAlgorithm.parameters", &tmp);
  if (ret < 0) {
    gnutls_assert();
    goto error;
  }

  ret = _gnutls_x509_read_pubkey_params(GNUTLS_PK_DSA, tmp.data, tmp.size,
                &pkey->params);
  _gnutls_free_datum(&tmp);
  if (ret < 0) {
    gnutls_assert();
    goto error;
  }

  if (_gnutls_mpi_cmp_ui(pkey->params.params[0], 0) == 0) {
    gnutls_assert();
    ret = GNUTLS_E_ILLEGAL_PARAMETER;
    goto error;
  }

  /* the public key can be generated as g^x mod p */
  ret = _gnutls_mpi_init(&pkey->params.params[3]);
  if (ret < 0) {
    gnutls_assert();
    goto error;
  }

  ret = _gnutls_mpi_powm(pkey->params.params[3], pkey->params.params[2],
             pkey->params.params[4], pkey->params.params[0]);
  if (ret < 0) {
    gnutls_assert();
    goto error;
  }

  pkey->params.algo = GNUTLS_PK_DSA;
  pkey->params.params_nr = DSA_PRIVATE_PARAMS;

  ret = _gnutls_asn1_encode_privkey(&pkey->key, &pkey->params);
  if (ret < 0) {
    gnutls_assert();
    goto error;
  }

  return 0;

error:
  if (pkey->params.params_nr != DSA_PRIVATE_PARAMS)
    _gnutls_mpi_release(&pkey->params.params[4]);
  return ret;
}

static int decode_ml_dsa_inner_private_key(const gnutls_datum_t *raw_key,
             size_t raw_pub_size,
             size_t raw_priv_size,
             gnutls_x509_privkey_t pkey)
{
  int ret;
  asn1_node inner_asn = NULL;

  /* libtasn1 doesn't support encoding instructions in CHOICE,
   * parse it manually */
  if (raw_key->size == 34 && raw_key->data[0] == 0x80 &&
      raw_key->data[1] == 0x20) {
    _gnutls_free_key_datum(&pkey->params.raw_seed);
    ret = _gnutls_set_datum(&pkey->params.raw_seed,
          &raw_key->data[2], 32);
    if (ret < 0)
      return gnutls_assert_val(ret);
  } else {
    int result;
    char choice_name[16];
    int choice_name_size = sizeof(choice_name) - 1;
    unsigned int etype;

    result = asn1_create_element(_gnutls_get_gnutls_asn(),
               "GNUTLS.MLDSAInnerPrivateKey",
               &inner_asn);
    if (result != ASN1_SUCCESS)
      return gnutls_assert_val(_gnutls_asn2err(result));

    result = _asn1_strict_der_decode(&inner_asn, raw_key->data,
             raw_key->size, NULL);
    if (result != ASN1_SUCCESS) {
      ret = gnutls_assert_val(_gnutls_asn2err(result));
      goto cleanup;
    }

    result = asn1_read_value_type(inner_asn, "", choice_name,
                &choice_name_size, &etype);
    if (result != ASN1_SUCCESS) {
      ret = gnutls_assert_val(_gnutls_asn2err(result));
      goto cleanup;
    }

    if (etype != ASN1_ETYPE_CHOICE) {
      ret = gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
      goto cleanup;
    }

    choice_name[choice_name_size] = '\0';
    if (strcmp(choice_name, "expandedKey") == 0) {
      _gnutls_free_key_datum(&pkey->params.raw_priv);
      ret = _gnutls_x509_read_value(inner_asn, choice_name,
                  &pkey->params.raw_priv);
      if (ret < 0) {
        gnutls_assert();
        goto cleanup;
      }

      /* The legacy format used in
       * liboqs/oqsprovider, which embeds public key
       * in the "privateKey" field after a private
       * key, falls to this branch */
      if (pkey->params.raw_priv.size ==
          raw_pub_size + raw_priv_size) {
        ret = _gnutls_set_datum(
          &pkey->params.raw_pub,
          &pkey->params.raw_priv
             .data[raw_priv_size],
          raw_pub_size);
        if (ret < 0) {
          gnutls_assert();
          goto cleanup;
        }
        pkey->params.raw_priv.size = raw_priv_size;
      }
    } else if (strcmp(choice_name, "both") == 0) {
      _gnutls_free_key_datum(&pkey->params.raw_seed);
      ret = _gnutls_x509_read_value(inner_asn, "both.seed",
                  &pkey->params.raw_seed);
      if (ret < 0) {
        gnutls_assert();
        goto cleanup;
      }
      if (pkey->params.raw_seed.size != 32) {
        ret = gnutls_assert_val(
          GNUTLS_E_INVALID_REQUEST);
        goto cleanup;
      }
      _gnutls_free_key_datum(&pkey->params.raw_priv);
      ret = _gnutls_x509_read_value(inner_asn,
                  "both.expandedKey",
                  &pkey->params.raw_priv);
      if (ret < 0) {
        gnutls_assert();
        goto cleanup;
      }
    } else {
      ret = gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
      goto cleanup;
    }
  }

  /* Expand seed if set */
  if (pkey->params.raw_seed.data) {
    /* For checking any inconsistency */
    gnutls_datum_t raw_priv =
      _gnutls_steal_datum(&pkey->params.raw_priv);

    pkey->params.pkflags |= GNUTLS_PK_FLAG_EXPAND_KEYS_FROM_SEED;
    ret = _gnutls_pk_generate_keys(pkey->params.algo, 0,
                 &pkey->params, 0);
    if (ret < 0) {
      gnutls_assert();
      _gnutls_free_key_datum(&raw_priv);
      goto cleanup;
    }

    if (raw_priv.data &&
        (pkey->params.raw_priv.size != raw_priv.size ||
         gnutls_memcmp(pkey->params.raw_priv.data, raw_priv.data,
           pkey->params.raw_priv.size) != 0)) {
      ret = gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
      _gnutls_free_key_datum(&raw_priv);
      goto cleanup;
    }
    _gnutls_free_key_datum(&raw_priv);
  }

cleanup:
  asn1_delete_structure2(&inner_asn, ASN1_DELETE_FLAG_ZEROIZE);
  return ret;
}

static int _decode_pkcs8_ml_dsa_key(asn1_node pkcs8_asn,
            gnutls_x509_privkey_t pkey,
            gnutls_pk_algorithm_t algo)
{
  int ret;
  unsigned int version;
  gnutls_datum_t raw_priv = { NULL, 0 };
  size_t raw_pub_size, raw_priv_size;

  switch (algo) {
  case GNUTLS_PK_MLDSA44:
    raw_priv_size = MLDSA44_PRIVKEY_SIZE;
    raw_pub_size = MLDSA44_PUBKEY_SIZE;
    break;
  case GNUTLS_PK_MLDSA65:
    raw_priv_size = MLDSA65_PRIVKEY_SIZE;
    raw_pub_size = MLDSA65_PUBKEY_SIZE;
    break;
  case GNUTLS_PK_MLDSA87:
    raw_priv_size = MLDSA87_PRIVKEY_SIZE;
    raw_pub_size = MLDSA87_PUBKEY_SIZE;
    break;
  default:
    return gnutls_assert_val(
      GNUTLS_E_UNSUPPORTED_SIGNATURE_ALGORITHM);
  }

  gnutls_pk_params_init(&pkey->params);
  pkey->params.algo = algo;

  ret = _gnutls_x509_read_uint(pkcs8_asn, "version", &version);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }
  if (version != 0 && version != 1)
    return gnutls_assert_val(GNUTLS_E_ASN1_DER_ERROR);

  ret = _gnutls_x509_read_value(pkcs8_asn, "privateKey", &raw_priv);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  /* Try the CHOICE format defined in
   * draft-ietf-lamps-dilithium-certificates-12, section 6 */
  ret = decode_ml_dsa_inner_private_key(&raw_priv, raw_pub_size,
                raw_priv_size, pkey);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  /* If version is 1, a public key may be embedded in a separate
   * field */
  if (version == 1) {
    /* For checking any inconsistency */
    gnutls_datum_t raw_pub =
      _gnutls_steal_datum(&pkey->params.raw_pub);

    ret = _gnutls_x509_read_value(pkcs8_asn, "publicKey",
                &pkey->params.raw_pub);
    if (ret < 0) {
      gnutls_assert();
      _gnutls_free_key_datum(&raw_pub);
      goto cleanup;
    }

    if (raw_pub.data &&
        (pkey->params.raw_pub.size != raw_pub.size ||
         gnutls_memcmp(pkey->params.raw_pub.data, raw_pub.data,
           pkey->params.raw_pub.size) != 0)) {
      ret = gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
      _gnutls_free_key_datum(&raw_pub);
      goto cleanup;
    }
    _gnutls_free_key_datum(&raw_pub);
  }

  /* Sanity check that the resulting keys have the expected sizes */
  if ((pkey->params.raw_pub.data &&
       pkey->params.raw_pub.size != raw_pub_size) ||
      pkey->params.raw_priv.size != raw_priv_size) {
    ret = gnutls_assert_val(GNUTLS_E_ASN1_DER_ERROR);
    goto cleanup;
  }

cleanup:
  if (ret < 0) {
    gnutls_pk_params_clear(&pkey->params);
    gnutls_pk_params_release(&pkey->params);
  }
  _gnutls_free_key_datum(&raw_priv);

  return ret;
}

static int decode_private_key_info(const gnutls_datum_t *der,
           gnutls_x509_privkey_t pkey)
{
  int result, len;
  char oid[MAX_OID_SIZE];
  asn1_node pkcs8_asn = NULL;
  gnutls_datum_t sder;
  int ret;

  if ((result = asn1_create_element(_gnutls_get_pkix(),
            "PKIX1.pkcs-8-PrivateKeyInfo",
            &pkcs8_asn)) != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }

  result =
    _asn1_strict_der_decode(&pkcs8_asn, der->data, der->size, NULL);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }

  /* Check the private key algorithm OID
   */
  len = sizeof(oid);
  result = asn1_read_value(pkcs8_asn, "privateKeyAlgorithm.algorithm",
         oid, &len);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }

  pkey->params.algo = gnutls_oid_to_pk(oid);
  if (pkey->params.algo == GNUTLS_PK_UNKNOWN) {
    gnutls_assert();
    _gnutls_debug_log(
      "PKCS #8 private key OID '%s' is unsupported.\n", oid);
    result = GNUTLS_E_UNKNOWN_PK_ALGORITHM;
    goto error;
  }

  /* Get the DER encoding of the actual private key.
   */

  switch (pkey->params.algo) {
  case GNUTLS_PK_RSA:
    result = _decode_pkcs8_rsa_key(pkcs8_asn, pkey);
    break;
  case GNUTLS_PK_RSA_PSS:
    result = _decode_pkcs8_rsa_pss_key(pkcs8_asn, pkey);
    break;
  case GNUTLS_PK_RSA_OAEP:
    result = _decode_pkcs8_rsa_oaep_key(pkcs8_asn, pkey);
    break;
  case GNUTLS_PK_DSA:
    result = _decode_pkcs8_dsa_key(pkcs8_asn, pkey);
    break;
  case GNUTLS_PK_ECDSA:
    result = _decode_pkcs8_ecc_key(pkcs8_asn, pkey);
    break;
  case GNUTLS_PK_EDDSA_ED25519:
  case GNUTLS_PK_EDDSA_ED448:
    result = _decode_pkcs8_eddsa_key(pkcs8_asn, pkey, oid);
    break;
  case GNUTLS_PK_ECDH_X25519:
  case GNUTLS_PK_ECDH_X448:
    result = _decode_pkcs8_modern_ecdh_key(pkcs8_asn, pkey, oid);
    break;
  case GNUTLS_PK_GOST_01:
  case GNUTLS_PK_GOST_12_256:
  case GNUTLS_PK_GOST_12_512:
    result = _decode_pkcs8_gost_key(pkcs8_asn, pkey,
            pkey->params.algo);
    break;
  case GNUTLS_PK_MLDSA44:
  case GNUTLS_PK_MLDSA65:
  case GNUTLS_PK_MLDSA87:
    result = _decode_pkcs8_ml_dsa_key(pkcs8_asn, pkey,
              pkey->params.algo);
    break;
  default:
    result = gnutls_assert_val(GNUTLS_E_UNIMPLEMENTED_FEATURE);
    goto error;
  }

  if (result < 0) {
    gnutls_assert();
    goto error;
  }

  /* check for provable parameters attribute */
  ret = _x509_parse_attribute(pkcs8_asn, "attributes", OID_ATTR_PROV_SEED,
            0, 1, &sder);
  if (ret >= 0) { /* ignore it when not being present */
    ret = _x509_decode_provable_seed(pkey, &sder);
    gnutls_free(sder.data);
    if (ret < 0) {
      gnutls_assert();
    }
  }

  result = 0;

error:
  asn1_delete_structure2(&pkcs8_asn, ASN1_DELETE_FLAG_ZEROIZE);
  return result;
}

/**
 * gnutls_x509_privkey_import_pkcs8:
 * @key: The data to store the parsed key
 * @data: The DER or PEM encoded key.
 * @format: One of DER or PEM
 * @password: the password to decrypt the key (if it is encrypted).
 * @flags: 0 if encrypted or GNUTLS_PKCS_PLAIN if not encrypted.
 *
 * This function will convert the given DER or PEM encoded PKCS8 2.0
 * encrypted key to the native gnutls_x509_privkey_t format. The
 * output will be stored in @key.  Both RSA and DSA keys can be
 * imported, and flags can only be used to indicate an unencrypted
 * key.
 *
 * The @password can be either ASCII or UTF-8 in the default PBES2
 * encryption schemas, or ASCII for the PKCS12 schemas.
 *
 * If the Certificate is PEM encoded it should have a header of
 * "ENCRYPTED PRIVATE KEY", or "PRIVATE KEY". You only need to
 * specify the flags if the key is DER encoded, since in that case
 * the encryption status cannot be auto-detected.
 *
 * If the %GNUTLS_PKCS_PLAIN flag is specified and the supplied data
 * are encrypted then %GNUTLS_E_DECRYPTION_FAILED is returned.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 **/
int gnutls_x509_privkey_import_pkcs8(gnutls_x509_privkey_t key,
             const gnutls_datum_t *data,
             gnutls_x509_crt_fmt_t format,
             const char *password, unsigned int flags)
{
  int result = 0, need_free = 0;
  gnutls_datum_t _data;

  if (key == NULL) {
    gnutls_assert();
    return GNUTLS_E_INVALID_REQUEST;
  }

  _data.data = data->data;
  _data.size = data->size;

  key->params.algo = GNUTLS_PK_UNKNOWN;

  /* If the Certificate is in PEM format then decode it
   */
  if (format == GNUTLS_X509_FMT_PEM) {
    /* Try the first header 
     */
    result = _gnutls_fbase64_decode(PEM_UNENCRYPTED_PKCS8,
            data->data, data->size, &_data);

    if (result < 0) { /* Try the encrypted header 
           */
      result = _gnutls_fbase64_decode(PEM_PKCS8, data->data,
              data->size, &_data);

      if (result < 0) {
        gnutls_assert();
        return result;
      }
    } else if (flags == 0)
      flags |= GNUTLS_PKCS_PLAIN;

    need_free = 1;
  }

  if (key->expanded) {
    _gnutls_x509_privkey_reinit(key);
  }
  key->expanded = 1;

  /* Here we don't check for password == NULL to maintain a backwards
   * compatibility behavior, with old versions that were encrypting using
   * a NULL password.
   */
  if (flags & GNUTLS_PKCS_PLAIN) {
    result = decode_private_key_info(&_data, key);
    if (result < 0) { /* check if it is encrypted */
      if (pkcs8_key_decode(&_data, "", key, 0) == 0)
        result = GNUTLS_E_DECRYPTION_FAILED;
    }
  } else { /* encrypted. */
    result = pkcs8_key_decode(&_data, password, key, 1);
  }

  if (result < 0) {
    gnutls_assert();
    goto cleanup;
  }

  /* This part is necessary to get the public key on certain algorithms.
   * In the import above we only get the private key. */
  result =
    _gnutls_pk_fixup(key->params.algo, GNUTLS_IMPORT, &key->params);
  if (result < 0) {
    gnutls_assert();
    goto cleanup;
  }

  if (need_free)
    _gnutls_free_datum(&_data);

  /* The key has now been decoded.
   */
  return 0;

cleanup:
  asn1_delete_structure2(&key->key, ASN1_DELETE_FLAG_ZEROIZE);
  key->params.algo = GNUTLS_PK_UNKNOWN;
  if (need_free) {
    zeroize_temp_key(_data.data, _data.size);
    _gnutls_free_datum(&_data);
  }
  return result;
}

Coverage Report

Created: 2025-07-23 07:18