/src/gnutls/lib/pubkey.c

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/*
 * GnuTLS public key support
 * Copyright (C) 2010-2012 Free Software Foundation, Inc.
 * Copyright (C) 2017 Red Hat, Inc.
 * 
 * Author: Nikos Mavrogiannopoulos
 *
 * 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 <gnutls/pkcs11.h>
#include <stdio.h>
#include <string.h>
#include "errors.h"
#include "datum.h"
#include "pkcs11_int.h"
#include <gnutls/abstract.h>
#include "tls-sig.h"
#include "pk.h"
#include "x509_int.h"
#include "num.h"
#include "x509/common.h"
#include "x509_b64.h"
#include "abstract_int.h"
#include "fips.h"
#include "urls.h"
#include "ecc.h"

static int pubkey_verify_hashed_data(const gnutls_sign_entry_st *se,
             const mac_entry_st *me,
             const gnutls_datum_t *hash,
             const gnutls_datum_t *signature,
             gnutls_pk_params_st *params,
             gnutls_x509_spki_st *sign_params,
             unsigned flags);

static int pubkey_supports_sig(gnutls_pubkey_t pubkey,
             const gnutls_sign_entry_st *se);

unsigned pubkey_to_bits(const gnutls_pk_params_st *params)
{
  switch (params->algo) {
  case GNUTLS_PK_RSA:
  case GNUTLS_PK_RSA_PSS:
  case GNUTLS_PK_RSA_OAEP:
    return _gnutls_mpi_get_nbits(params->params[RSA_MODULUS]);
  case GNUTLS_PK_DSA:
    return _gnutls_mpi_get_nbits(params->params[DSA_P]);
  case GNUTLS_PK_ECDSA:
  case GNUTLS_PK_EDDSA_ED25519:
  case GNUTLS_PK_EDDSA_ED448:
  case GNUTLS_PK_ECDH_X25519:
  case GNUTLS_PK_ECDH_X448:
  case GNUTLS_PK_GOST_01:
  case GNUTLS_PK_GOST_12_256:
  case GNUTLS_PK_GOST_12_512:
    return gnutls_ecc_curve_get_size(params->curve) * 8;
  default:
    return 0;
  }
}

/**
 * gnutls_pubkey_get_pk_algorithm:
 * @key: should contain a #gnutls_pubkey_t type
 * @bits: If set will return the number of bits of the parameters (may be NULL)
 *
 * This function will return the public key algorithm of a public
 * key and if possible will return a number of bits that indicates
 * the security parameter of the key.
 *
 * Returns: a member of the #gnutls_pk_algorithm_t enumeration on
 *   success, or a negative error code on error.
 *
 * Since: 2.12.0
 **/
int gnutls_pubkey_get_pk_algorithm(gnutls_pubkey_t key, unsigned int *bits)
{
  if (bits)
    *bits = key->bits;

  return key->params.algo;
}

/**
 * gnutls_pubkey_get_key_usage:
 * @key: should contain a #gnutls_pubkey_t type
 * @usage: If set will return the number of bits of the parameters (may be NULL)
 *
 * This function will return the key usage of the public key.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 2.12.0
 **/
int gnutls_pubkey_get_key_usage(gnutls_pubkey_t key, unsigned int *usage)
{
  if (usage)
    *usage = key->key_usage;

  return 0;
}

/**
 * gnutls_pubkey_init:
 * @key: A pointer to the type to be initialized
 *
 * This function will initialize a public key.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 2.12.0
 **/
int gnutls_pubkey_init(gnutls_pubkey_t *key)
{
  *key = NULL;
  FAIL_IF_LIB_ERROR;

  *key = gnutls_calloc(1, sizeof(struct gnutls_pubkey_st));
  if (*key == NULL) {
    gnutls_assert();
    return GNUTLS_E_MEMORY_ERROR;
  }

  return 0;
}

/**
 * gnutls_pubkey_deinit:
 * @key: The key to be deinitialized
 *
 * This function will deinitialize a public key structure.
 *
 * Since: 2.12.0
 **/
void gnutls_pubkey_deinit(gnutls_pubkey_t key)
{
  if (!key)
    return;
  gnutls_pk_params_release(&key->params);
  gnutls_free(key);
}

/**
 * gnutls_pubkey_import_x509:
 * @key: The public key
 * @crt: The certificate to be imported
 * @flags: should be zero
 *
 * This function will import the given public key to the abstract
 * #gnutls_pubkey_t type.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 2.12.0
 **/
int gnutls_pubkey_import_x509(gnutls_pubkey_t key, gnutls_x509_crt_t crt,
            unsigned int flags)
{
  int ret;

  gnutls_pk_params_release(&key->params);
  /* params initialized in _gnutls_x509_crt_get_mpis */

  ret = gnutls_x509_crt_get_pk_algorithm(crt, &key->bits);
  if (ret < 0)
    return gnutls_assert_val(ret);

  key->params.algo = ret;

  ret = gnutls_x509_crt_get_key_usage(crt, &key->key_usage, NULL);
  if (ret < 0)
    key->key_usage = 0;

  ret = _gnutls_x509_crt_get_mpis(crt, &key->params);
  if (ret < 0) {
    gnutls_assert();
    return ret;
  }

  return 0;
}

/**
 * gnutls_pubkey_import_x509_crq:
 * @key: The public key
 * @crq: The certificate to be imported
 * @flags: should be zero
 *
 * This function will import the given public key to the abstract
 * #gnutls_pubkey_t type.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.1.5
 **/
int gnutls_pubkey_import_x509_crq(gnutls_pubkey_t key, gnutls_x509_crq_t crq,
          unsigned int flags)
{
  int ret;

  gnutls_pk_params_release(&key->params);
  /* params initialized in _gnutls_x509_crq_get_mpis */

  key->params.algo = gnutls_x509_crq_get_pk_algorithm(crq, &key->bits);

  ret = gnutls_x509_crq_get_key_usage(crq, &key->key_usage, NULL);
  if (ret < 0)
    key->key_usage = 0;

  ret = _gnutls_x509_crq_get_mpis(crq, &key->params);
  if (ret < 0) {
    gnutls_assert();
    return ret;
  }

  return 0;
}

/**
 * gnutls_pubkey_import_privkey:
 * @key: The public key
 * @pkey: The private key
 * @usage: GNUTLS_KEY_* key usage flags.
 * @flags: should be zero
 *
 * Imports the public key from a private.  This function will import
 * the given public key to the abstract #gnutls_pubkey_t type.
 *
 * Note that in certain keys this operation may not be possible, e.g.,
 * in other than RSA PKCS#11 keys.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 2.12.0
 **/
int gnutls_pubkey_import_privkey(gnutls_pubkey_t key, gnutls_privkey_t pkey,
         unsigned int usage, unsigned int flags)
{
  gnutls_pk_params_release(&key->params);
  gnutls_pk_params_init(&key->params);

  key->key_usage = usage;
  key->params.algo = gnutls_privkey_get_pk_algorithm(pkey, &key->bits);

  return _gnutls_privkey_get_public_mpis(pkey, &key->params);
}

/**
 * gnutls_pubkey_get_preferred_hash_algorithm:
 * @key: Holds the certificate
 * @hash: The result of the call with the hash algorithm used for signature
 * @mand: If non zero it means that the algorithm MUST use this hash. May be NULL.
 *
 * This function will read the certificate and return the appropriate digest
 * algorithm to use for signing with this certificate. Some certificates (i.e.
 * DSA might not be able to sign without the preferred algorithm).
 *
 * To get the signature algorithm instead of just the hash use gnutls_pk_to_sign()
 * with the algorithm of the certificate/key and the provided @hash.
 *
 * Returns: the 0 if the hash algorithm is found. A negative error code is
 * returned on error.
 *
 * Since: 2.12.0
 **/
int gnutls_pubkey_get_preferred_hash_algorithm(gnutls_pubkey_t key,
                 gnutls_digest_algorithm_t *hash,
                 unsigned int *mand)
{
  int ret;
  const mac_entry_st *me;

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

  if (mand)
    *mand = 0;

  switch (key->params.algo) {
  case GNUTLS_PK_DSA:
    if (mand)
      *mand = 1;
    FALLTHROUGH;
  case GNUTLS_PK_ECDSA:

    me = _gnutls_dsa_q_to_hash(&key->params, NULL);
    if (hash)
      *hash = (gnutls_digest_algorithm_t)me->id;

    ret = 0;
    break;
  case GNUTLS_PK_EDDSA_ED25519:
    if (hash)
      *hash = GNUTLS_DIG_SHA512;

    ret = 0;
    break;
  case GNUTLS_PK_EDDSA_ED448:
    if (hash)
      *hash = GNUTLS_DIG_SHAKE_256;

    ret = 0;
    break;
  case GNUTLS_PK_GOST_01:
  case GNUTLS_PK_GOST_12_256:
  case GNUTLS_PK_GOST_12_512:
    if (hash)
      *hash = _gnutls_gost_digest(key->params.algo);
    if (mand)
      *mand = 1;

    ret = 0;
    break;
  case GNUTLS_PK_RSA_PSS:
    if (mand && key->params.spki.rsa_pss_dig)
      *mand = 1;

    if (hash) {
      if (key->params.spki.rsa_pss_dig) {
        *hash = key->params.spki.rsa_pss_dig;
      } else {
        *hash = _gnutls_pk_bits_to_sha_hash(
          pubkey_to_bits(&key->params));
      }
    }
    ret = 0;
    break;
  case GNUTLS_PK_RSA:
    if (hash)
      *hash = _gnutls_pk_bits_to_sha_hash(
        pubkey_to_bits(&key->params));
    ret = 0;
    break;

  default:
    gnutls_assert();
    ret = GNUTLS_E_INTERNAL_ERROR;
  }

  return ret;
}

#ifdef ENABLE_PKCS11

/* The EC_PARAMS attribute can contain either printable string with curve name
 * or OID defined in RFC 8410 */
int _gnutls_pubkey_parse_ecc_eddsa_params(const gnutls_datum_t *parameters,
            gnutls_ecc_curve_t *outcurve)
{
  gnutls_ecc_curve_t curve = GNUTLS_ECC_CURVE_INVALID;
  asn1_node asn1 = NULL;
  unsigned int etype = ASN1_ETYPE_INVALID;
  char str[MAX_OID_SIZE];
  int str_size;
  int ret;

  ret = asn1_create_element(_gnutls_get_gnutls_asn(),
          "GNUTLS.pkcs-11-ec-Parameters", &asn1);
  if (ret != ASN1_SUCCESS) {
    gnutls_assert();
    return _gnutls_asn2err(ret);
  }

  ret = asn1_der_decoding(&asn1, parameters->data, parameters->size,
        NULL);
  if (ret != ASN1_SUCCESS) {
    gnutls_assert();
    ret = _gnutls_asn2err(ret);
    goto cleanup;
  }

  /* Read the type of choice.
   */
  str_size = sizeof(str) - 1;
  ret = asn1_read_value(asn1, "", str, &str_size);
  if (ret != ASN1_SUCCESS) {
    gnutls_assert();
    ret = _gnutls_asn2err(ret);
    goto cleanup;
  }
  str[str_size] = 0;

  /* Convert the choice to enum type */
  if (strcmp(str, "oId") == 0) {
    etype = ASN1_ETYPE_OBJECT_ID;
  } else if (strcmp(str, "curveName") == 0) {
    etype = ASN1_ETYPE_PRINTABLE_STRING;
  }

  str_size = sizeof(str) - 1;
  switch (etype) {
  case ASN1_ETYPE_OBJECT_ID:
    ret = asn1_read_value(asn1, "oId", str, &str_size);
    if (ret != ASN1_SUCCESS) {
      gnutls_assert();
      ret = _gnutls_asn2err(ret);
      break;
    }

    curve = gnutls_oid_to_ecc_curve(str);
    if (curve != GNUTLS_ECC_CURVE_ED25519 &&
        curve != GNUTLS_ECC_CURVE_ED448) {
      _gnutls_debug_log(
        "Curve %s is not supported for EdDSA\n", str);
      gnutls_assert();
      curve = GNUTLS_ECC_CURVE_INVALID;
      ret = GNUTLS_E_ECC_UNSUPPORTED_CURVE;
      break;
    }

    ret = GNUTLS_E_SUCCESS;
    break;

  case ASN1_ETYPE_PRINTABLE_STRING:
    ret = asn1_read_value(asn1, "curveName", str, &str_size);
    if (ret != ASN1_SUCCESS) {
      gnutls_assert();
      ret = _gnutls_asn2err(ret);
      break;
    }

    if (str_size == strlen("edwards25519") &&
        strncmp(str, "edwards25519", str_size) == 0) {
      curve = GNUTLS_ECC_CURVE_ED25519;
      ret = GNUTLS_E_SUCCESS;
      break;
    } else if (str_size == strlen("edwards448") &&
         strncmp(str, "edwards448", str_size) == 0) {
      curve = GNUTLS_ECC_CURVE_ED448;
      ret = GNUTLS_E_SUCCESS;
      break;
    }
    /* FALLTHROUGH */

  default:
    /* Neither of CHOICEs found. Fail */
    gnutls_assert();
    ret = GNUTLS_E_ECC_UNSUPPORTED_CURVE;
    curve = GNUTLS_ECC_CURVE_INVALID;
    break;
  }

cleanup:
  asn1_delete_structure(&asn1);
  *outcurve = curve;
  return ret;
}

static int gnutls_pubkey_import_ecc_eddsa(gnutls_pubkey_t key,
            const gnutls_datum_t *parameters,
            const gnutls_datum_t *ecpoint)
{
  int ret;

  gnutls_ecc_curve_t curve = GNUTLS_ECC_CURVE_INVALID;
  gnutls_datum_t raw_point = { NULL, 0 };

  ret = _gnutls_pubkey_parse_ecc_eddsa_params(parameters, &curve);
  if (ret < 0) {
    return gnutls_assert_val(ret);
  }

  ret = _gnutls_x509_decode_string(ASN1_ETYPE_OCTET_STRING, ecpoint->data,
           ecpoint->size, &raw_point, 0);
  if (ret < 0) {
    gnutls_assert();
    gnutls_free(raw_point.data);
    return ret;
  }
  ret = gnutls_pubkey_import_ecc_raw(key, curve, &raw_point, NULL);

  gnutls_free(raw_point.data);
  return ret;
}

/* Same as above, but for Edwards key agreement */
static int gnutls_pubkey_parse_ecc_ecdh_params(const gnutls_datum_t *parameters,
                 gnutls_ecc_curve_t *outcurve)
{
  gnutls_ecc_curve_t curve = GNUTLS_ECC_CURVE_INVALID;
  asn1_node asn1 = NULL;
  unsigned int etype = ASN1_ETYPE_INVALID;
  char str[MAX_OID_SIZE];
  int str_size;
  int ret;

  ret = asn1_create_element(_gnutls_get_gnutls_asn(),
          "GNUTLS.pkcs-11-ec-Parameters", &asn1);
  if (ret != ASN1_SUCCESS) {
    gnutls_assert();
    return _gnutls_asn2err(ret);
  }

  ret = asn1_der_decoding(&asn1, parameters->data, parameters->size,
        NULL);
  if (ret != ASN1_SUCCESS) {
    gnutls_assert();
    ret = _gnutls_asn2err(ret);
    goto cleanup;
  }

  /* Read the type of choice.
   */
  str_size = sizeof(str) - 1;
  ret = asn1_read_value(asn1, "", str, &str_size);
  if (ret != ASN1_SUCCESS) {
    gnutls_assert();
    ret = _gnutls_asn2err(ret);
    goto cleanup;
  }
  str[str_size] = 0;

  /* Convert the choice to enum type */
  if (strcmp(str, "oId") == 0) {
    etype = ASN1_ETYPE_OBJECT_ID;
  } else if (strcmp(str, "curveName") == 0) {
    etype = ASN1_ETYPE_PRINTABLE_STRING;
  }

  str_size = sizeof(str) - 1;
  switch (etype) {
  case ASN1_ETYPE_OBJECT_ID:
    ret = asn1_read_value(asn1, "oId", str, &str_size);
    if (ret != ASN1_SUCCESS) {
      gnutls_assert();
      ret = _gnutls_asn2err(ret);
      break;
    }

    curve = gnutls_oid_to_ecc_curve(str);
    if (curve != GNUTLS_ECC_CURVE_X25519 &&
        curve != GNUTLS_ECC_CURVE_X448) {
      _gnutls_debug_log(
        "Curve %s is not supported for Edwards-based key agreement\n",
        str);
      gnutls_assert();
      curve = GNUTLS_ECC_CURVE_INVALID;
      ret = GNUTLS_E_ECC_UNSUPPORTED_CURVE;
      break;
    }

    ret = GNUTLS_E_SUCCESS;
    break;

  case ASN1_ETYPE_PRINTABLE_STRING:
    ret = asn1_read_value(asn1, "curveName", str, &str_size);
    if (ret != ASN1_SUCCESS) {
      gnutls_assert();
      ret = _gnutls_asn2err(ret);
      break;
    }

    if (str_size == strlen("x25519") &&
        strncmp(str, "x25519", str_size) == 0) {
      curve = GNUTLS_ECC_CURVE_X25519;
      ret = GNUTLS_E_SUCCESS;
      break;
    } else if (str_size == strlen("x448") &&
         strncmp(str, "x448", str_size) == 0) {
      curve = GNUTLS_ECC_CURVE_X448;
      ret = GNUTLS_E_SUCCESS;
      break;
    }
    /* FALLTHROUGH */

  default:
    /* Neither of CHOICEs found. Fail */
    gnutls_assert();
    ret = GNUTLS_E_ECC_UNSUPPORTED_CURVE;
    curve = GNUTLS_ECC_CURVE_INVALID;
    break;
  }

cleanup:
  asn1_delete_structure(&asn1);
  *outcurve = curve;
  return ret;
}

static int gnutls_pubkey_import_ecc_ecdh(gnutls_pubkey_t key,
           const gnutls_datum_t *parameters,
           const gnutls_datum_t *ecpoint)
{
  int ret;

  gnutls_ecc_curve_t curve = GNUTLS_ECC_CURVE_INVALID;
  gnutls_datum_t raw_point = { NULL, 0 };

  ret = gnutls_pubkey_parse_ecc_ecdh_params(parameters, &curve);
  if (ret < 0) {
    return gnutls_assert_val(ret);
  }

  ret = _gnutls_x509_decode_string(ASN1_ETYPE_OCTET_STRING, ecpoint->data,
           ecpoint->size, &raw_point, 0);
  if (ret < 0) {
    gnutls_assert();
    gnutls_free(raw_point.data);
    return ret;
  }
  ret = gnutls_pubkey_import_ecc_raw(key, curve, &raw_point, NULL);

  gnutls_free(raw_point.data);
  return ret;
}

/**
 * gnutls_pubkey_import_pkcs11:
 * @key: The public key
 * @obj: The parameters to be imported
 * @flags: should be zero
 *
 * Imports a public key from a pkcs11 key. This function will import
 * the given public key to the abstract #gnutls_pubkey_t type.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 2.12.0
 **/
int gnutls_pubkey_import_pkcs11(gnutls_pubkey_t key, gnutls_pkcs11_obj_t obj,
        unsigned int flags)
{
  int ret, type;

  type = gnutls_pkcs11_obj_get_type(obj);
  if (type != GNUTLS_PKCS11_OBJ_PUBKEY &&
      type != GNUTLS_PKCS11_OBJ_X509_CRT) {
    gnutls_assert();
    return GNUTLS_E_INVALID_REQUEST;
  }

  if (type == GNUTLS_PKCS11_OBJ_X509_CRT) {
    gnutls_x509_crt_t xcrt;

    ret = gnutls_x509_crt_init(&xcrt);
    if (ret < 0) {
      gnutls_assert() return ret;
    }

    ret = gnutls_x509_crt_import_pkcs11(xcrt, obj);
    if (ret < 0) {
      gnutls_assert();
      goto cleanup_crt;
    }

    ret = gnutls_pubkey_import_x509(key, xcrt, 0);
    if (ret < 0) {
      gnutls_assert();
      goto cleanup_crt;
    }

    ret = gnutls_x509_crt_get_key_usage(xcrt, &key->key_usage,
                NULL);
    if (ret < 0)
      key->key_usage = 0;

    ret = 0;
  cleanup_crt:
    gnutls_x509_crt_deinit(xcrt);
    return ret;
  }

  key->key_usage = obj->key_usage;

  switch (obj->pk_algorithm) {
  case GNUTLS_PK_RSA:
  case GNUTLS_PK_RSA_PSS:
    ret = gnutls_pubkey_import_rsa_raw(key, &obj->pubkey[0],
               &obj->pubkey[1]);
    break;
  case GNUTLS_PK_DSA:
    ret = gnutls_pubkey_import_dsa_raw(key, &obj->pubkey[0],
               &obj->pubkey[1],
               &obj->pubkey[2],
               &obj->pubkey[3]);
    break;
  case GNUTLS_PK_EC:
    ret = gnutls_pubkey_import_ecc_x962(key, &obj->pubkey[0],
                &obj->pubkey[1]);
    break;
  case GNUTLS_PK_EDDSA_ED25519:
  case GNUTLS_PK_EDDSA_ED448:
    ret = gnutls_pubkey_import_ecc_eddsa(key, &obj->pubkey[0],
                 &obj->pubkey[1]);
    break;
  case GNUTLS_PK_ECDH_X25519:
    ret = gnutls_pubkey_import_ecc_ecdh(key, &obj->pubkey[0],
                &obj->pubkey[1]);
    break;
  default:
    gnutls_assert();
    return GNUTLS_E_UNIMPLEMENTED_FEATURE;
  }

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

  return 0;
}

#endif /* ENABLE_PKCS11 */

/**
 * gnutls_pubkey_export:
 * @key: Holds the certificate
 * @format: the format of output params. One of PEM or DER.
 * @output_data: will contain a certificate 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 public key to DER or PEM format.
 * The contents of the exported data is the SubjectPublicKeyInfo
 * X.509 structure.
 *
 * 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 CERTIFICATE".
 *
 * Returns: In case of failure a negative error code will be
 *   returned, and 0 on success.
 *
 * Since: 2.12.0
 **/
int gnutls_pubkey_export(gnutls_pubkey_t key, gnutls_x509_crt_fmt_t format,
       void *output_data, size_t *output_data_size)
{
  int result;
  asn1_node spk = NULL;

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

  if ((result = asn1_create_element(_gnutls_get_pkix(),
            "PKIX1.SubjectPublicKeyInfo",
            &spk)) != ASN1_SUCCESS) {
    gnutls_assert();
    return _gnutls_asn2err(result);
  }

  result = _gnutls_x509_encode_and_copy_PKI_params(spk, "", &key->params);
  if (result < 0) {
    gnutls_assert();
    goto cleanup;
  }

  result = _gnutls_x509_export_int_named(spk, "", format, PEM_PK,
                 output_data, output_data_size);
  if (result < 0) {
    gnutls_assert();
    goto cleanup;
  }

  result = 0;

cleanup:
  asn1_delete_structure(&spk);

  return result;
}

/**
 * gnutls_pubkey_export2:
 * @key: Holds the certificate
 * @format: the format of output params. One of PEM or DER.
 * @out: will contain a certificate PEM or DER encoded
 *
 * This function will export the public key to DER or PEM format.
 * The contents of the exported data is the SubjectPublicKeyInfo
 * X.509 structure.
 *
 * The output buffer will be allocated using gnutls_malloc().
 *
 * If the structure is PEM encoded, it will have a header
 * of "BEGIN CERTIFICATE".
 *
 * Returns: In case of failure a negative error code will be
 *   returned, and 0 on success.
 *
 * Since: 3.1.3
 **/
int gnutls_pubkey_export2(gnutls_pubkey_t key, gnutls_x509_crt_fmt_t format,
        gnutls_datum_t *out)
{
  int result;
  asn1_node spk = NULL;

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

  if ((result = asn1_create_element(_gnutls_get_pkix(),
            "PKIX1.SubjectPublicKeyInfo",
            &spk)) != ASN1_SUCCESS) {
    gnutls_assert();
    return _gnutls_asn2err(result);
  }

  result = _gnutls_x509_encode_and_copy_PKI_params(spk, "", &key->params);
  if (result < 0) {
    gnutls_assert();
    goto cleanup;
  }

  result = _gnutls_x509_export_int_named2(spk, "", format, PEM_PK, out);
  if (result < 0) {
    gnutls_assert();
    goto cleanup;
  }

  result = 0;

cleanup:
  asn1_delete_structure(&spk);

  return result;
}

/**
 * gnutls_pubkey_get_key_id:
 * @key: Holds the public key
 * @flags: should be one of the flags from %gnutls_keyid_flags_t
 * @output_data: will contain the key ID
 * @output_data_size: holds the size of output_data (and will be
 *   replaced by the actual size of parameters)
 *
 * This function will return a unique ID that depends on the public
 * key parameters. This ID can be used in checking whether a
 * certificate corresponds to the given public key.
 *
 * 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.  The output will normally be a SHA-1 hash output,
 * which is 20 bytes.
 *
 * Returns: In case of failure a negative error code will be
 *   returned, and 0 on success.
 *
 * Since: 2.12.0
 **/
int gnutls_pubkey_get_key_id(gnutls_pubkey_t key, unsigned int flags,
           unsigned char *output_data,
           size_t *output_data_size)
{
  int ret = 0;

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

  ret = _gnutls_get_key_id(&key->params, output_data, output_data_size,
         flags);
  if (ret < 0) {
    gnutls_assert();
    return ret;
  }

  return 0;
}

/**
 * gnutls_pubkey_export_rsa_raw2:
 * @key: Holds the certificate
 * @m: will hold the modulus (may be %NULL)
 * @e: will hold the public exponent (may be %NULL)
 * @flags: flags from %gnutls_abstract_export_flags_t
 *
 * This function will export the RSA public key's parameters found in
 * the given structure.  The new parameters will be allocated using
 * gnutls_malloc() and will be stored in the appropriate datum.
 *
 * This function allows for %NULL parameters since 3.4.1.
 *
 * Returns: %GNUTLS_E_SUCCESS on success, otherwise a negative error code.
 *
 * Since: 3.6.0
 **/
int gnutls_pubkey_export_rsa_raw2(gnutls_pubkey_t key, gnutls_datum_t *m,
          gnutls_datum_t *e, unsigned flags)
{
  int ret;
  mpi_dprint_func dprint = _gnutls_mpi_dprint_lz;

  if (flags & GNUTLS_EXPORT_FLAG_NO_LZ)
    dprint = _gnutls_mpi_dprint;

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

  if (!GNUTLS_PK_IS_RSA(key->params.algo)) {
    gnutls_assert();
    return GNUTLS_E_INVALID_REQUEST;
  }

  if (m) {
    ret = dprint(key->params.params[0], m);
    if (ret < 0) {
      gnutls_assert();
      return ret;
    }
  }

  if (e) {
    ret = dprint(key->params.params[1], e);
    if (ret < 0) {
      gnutls_assert();
      _gnutls_free_datum(m);
      return ret;
    }
  }

  return 0;
}

/**
 * gnutls_pubkey_export_rsa_raw:
 * @key: Holds the certificate
 * @m: will hold the modulus (may be %NULL)
 * @e: will hold the public exponent (may be %NULL)
 *
 * This function will export the RSA public key's parameters found in
 * the given structure.  The new parameters will be allocated using
 * gnutls_malloc() and will be stored in the appropriate datum.
 *
 * This function allows for %NULL parameters since 3.4.1.
 *
 * Returns: %GNUTLS_E_SUCCESS on success, otherwise a negative error code.
 *
 * Since: 3.3.0
 **/
int gnutls_pubkey_export_rsa_raw(gnutls_pubkey_t key, gnutls_datum_t *m,
         gnutls_datum_t *e)
{
  return gnutls_pubkey_export_rsa_raw2(key, m, e, 0);
}

/**
 * gnutls_pubkey_export_dsa_raw:
 * @key: Holds the public key
 * @p: will hold the p (may be %NULL)
 * @q: will hold the q (may be %NULL)
 * @g: will hold the g (may be %NULL)
 * @y: will hold the y (may be %NULL)
 *
 * This function will export the DSA public key's parameters found in
 * the given certificate.  The new parameters will be allocated using
 * gnutls_malloc() and will be stored in the appropriate datum.
 *
 * This function allows for %NULL parameters since 3.4.1.
 *
 * Returns: %GNUTLS_E_SUCCESS on success, otherwise a negative error code.
 *
 * Since: 3.3.0
 **/
int gnutls_pubkey_export_dsa_raw(gnutls_pubkey_t key, gnutls_datum_t *p,
         gnutls_datum_t *q, gnutls_datum_t *g,
         gnutls_datum_t *y)
{
  return gnutls_pubkey_export_dsa_raw2(key, p, q, g, y, 0);
}

/**
 * gnutls_pubkey_export_dsa_raw2:
 * @key: Holds the public key
 * @p: will hold the p (may be %NULL)
 * @q: will hold the q (may be %NULL)
 * @g: will hold the g (may be %NULL)
 * @y: will hold the y (may be %NULL)
 * @flags: flags from %gnutls_abstract_export_flags_t
 *
 * This function will export the DSA public key's parameters found in
 * the given certificate.  The new parameters will be allocated using
 * gnutls_malloc() and will be stored in the appropriate datum.
 *
 * This function allows for %NULL parameters since 3.4.1.
 *
 * Returns: %GNUTLS_E_SUCCESS on success, otherwise a negative error code.
 *
 * Since: 3.6.0
 **/
int gnutls_pubkey_export_dsa_raw2(gnutls_pubkey_t key, gnutls_datum_t *p,
          gnutls_datum_t *q, gnutls_datum_t *g,
          gnutls_datum_t *y, unsigned flags)
{
  int ret;
  mpi_dprint_func dprint = _gnutls_mpi_dprint_lz;

  if (flags & GNUTLS_EXPORT_FLAG_NO_LZ)
    dprint = _gnutls_mpi_dprint;

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

  if (key->params.algo != GNUTLS_PK_DSA) {
    gnutls_assert();
    return GNUTLS_E_INVALID_REQUEST;
  }

  /* P */
  if (p) {
    ret = dprint(key->params.params[0], p);
    if (ret < 0) {
      gnutls_assert();
      return ret;
    }
  }

  /* Q */
  if (q) {
    ret = dprint(key->params.params[1], q);
    if (ret < 0) {
      gnutls_assert();
      _gnutls_free_datum(p);
      return ret;
    }
  }

  /* G */
  if (g) {
    ret = dprint(key->params.params[2], g);
    if (ret < 0) {
      gnutls_assert();
      _gnutls_free_datum(p);
      _gnutls_free_datum(q);
      return ret;
    }
  }

  /* Y */
  if (y) {
    ret = dprint(key->params.params[3], y);
    if (ret < 0) {
      gnutls_assert();
      _gnutls_free_datum(p);
      _gnutls_free_datum(g);
      _gnutls_free_datum(q);
      return ret;
    }
  }

  return 0;
}

/**
 * gnutls_pubkey_export_dh_raw:
 * @key: Holds the public key
 * @params: will hold the Diffie-Hellman parameter (optional), must be initialized
 * @y: will hold the y
 * @flags: flags from %gnutls_abstract_export_flags_t
 *
 * This function will export the Diffie-Hellman public key parameter
 * found in the given public key.  The new parameter will be allocated
 * using gnutls_malloc() and will be stored in the appropriate datum.
 *
 * To retrieve other parameters common in both public key and private
 * key, use gnutls_dh_params_export_raw().
 *
 * This function allows for %NULL parameters since 3.4.1.
 *
 * Returns: %GNUTLS_E_SUCCESS on success, otherwise a negative error code.
 *
 * Since: 3.8.2
 **/
int gnutls_pubkey_export_dh_raw(gnutls_pubkey_t key, gnutls_dh_params_t params,
        gnutls_datum_t *y, unsigned flags)
{
  int ret;
  mpi_dprint_func dprint = _gnutls_mpi_dprint_lz;

  if (flags & GNUTLS_EXPORT_FLAG_NO_LZ) {
    dprint = _gnutls_mpi_dprint;
  }

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

  if (key->params.algo != GNUTLS_PK_DH) {
    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
  }

  if (params) {
    params->params[0] = _gnutls_mpi_copy(key->params.params[DH_P]);
    params->params[1] = _gnutls_mpi_copy(key->params.params[DH_G]);
    if (key->params.params[DH_Q]) {
      params->params[2] =
        _gnutls_mpi_copy(key->params.params[DH_Q]);
    }
    params->q_bits = key->params.qbits;
  }

  /* Y */
  if (y) {
    ret = dprint(key->params.params[DH_Y], y);
    if (ret < 0) {
      return gnutls_assert_val(ret);
    }
  }

  return 0;
}

/**
 * gnutls_pubkey_export_ecc_raw:
 * @key: Holds the public key
 * @curve: will hold the curve (may be %NULL)
 * @x: will hold x-coordinate (may be %NULL)
 * @y: will hold y-coordinate (may be %NULL)
 *
 * This function will export the ECC public key's parameters found in
 * the given key.  The new parameters will be allocated using
 * gnutls_malloc() and will be stored in the appropriate datum.
 *
 * In EdDSA curves the @y parameter will be %NULL and the other parameters
 * will be in the native format for the curve.
 *
 * This function allows for %NULL parameters since 3.4.1.
 *
 * Returns: %GNUTLS_E_SUCCESS on success, otherwise a negative error code.
 *
 * Since: 3.0
 **/
int gnutls_pubkey_export_ecc_raw(gnutls_pubkey_t key, gnutls_ecc_curve_t *curve,
         gnutls_datum_t *x, gnutls_datum_t *y)
{
  return gnutls_pubkey_export_ecc_raw2(key, curve, x, y, 0);
}

/**
 * gnutls_pubkey_export_ecc_raw2:
 * @key: Holds the public key
 * @curve: will hold the curve (may be %NULL)
 * @x: will hold x-coordinate (may be %NULL)
 * @y: will hold y-coordinate (may be %NULL)
 * @flags: flags from %gnutls_abstract_export_flags_t
 *
 * This function will export the ECC public key's parameters found in
 * the given key.  The new parameters will be allocated using
 * gnutls_malloc() and will be stored in the appropriate datum.
 *
 * In EdDSA curves the @y parameter will be %NULL and the other parameters
 * will be in the native format for the curve.
 *
 * This function allows for %NULL parameters since 3.4.1.
 *
 * Returns: %GNUTLS_E_SUCCESS on success, otherwise a negative error code.
 *
 * Since: 3.6.0
 **/
int gnutls_pubkey_export_ecc_raw2(gnutls_pubkey_t key,
          gnutls_ecc_curve_t *curve, gnutls_datum_t *x,
          gnutls_datum_t *y, unsigned int flags)
{
  int ret;
  mpi_dprint_func dprint = _gnutls_mpi_dprint_lz;

  if (flags & GNUTLS_EXPORT_FLAG_NO_LZ)
    dprint = _gnutls_mpi_dprint;

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

  if (!IS_EC(key->params.algo)) {
    gnutls_assert();
    return GNUTLS_E_INVALID_REQUEST;
  }

  if (curve)
    *curve = key->params.curve;

  if (key->params.algo == GNUTLS_PK_EDDSA_ED25519 ||
      key->params.algo == GNUTLS_PK_EDDSA_ED448 ||
      key->params.algo == GNUTLS_PK_ECDH_X25519 ||
      key->params.algo == GNUTLS_PK_ECDH_X448) {
    if (x) {
      ret = _gnutls_set_datum(x, key->params.raw_pub.data,
            key->params.raw_pub.size);
      if (ret < 0)
        return gnutls_assert_val(ret);
    }
    if (y) {
      y->data = NULL;
      y->size = 0;
    }
    return 0;
  }

  /* ECDSA */

  /* X */
  if (x) {
    ret = dprint(key->params.params[ECC_X], x);
    if (ret < 0) {
      gnutls_assert();
      return ret;
    }
  }

  /* Y */
  if (y) {
    ret = dprint(key->params.params[ECC_Y], y);
    if (ret < 0) {
      gnutls_assert();
      _gnutls_free_datum(x);
      return ret;
    }
  }

  return 0;
}

/**
 * gnutls_pubkey_export_ecc_x962:
 * @key: Holds the public key
 * @parameters: DER encoding of an ANSI X9.62 parameters
 * @ecpoint: DER encoding of ANSI X9.62 ECPoint
 *
 * This function will export the ECC public key's parameters found in
 * the given certificate.  The new parameters will be allocated using
 * gnutls_malloc() and will be stored in the appropriate datum.
 *
 * Returns: %GNUTLS_E_SUCCESS on success, otherwise a negative error code.
 *
 * Since: 3.3.0
 **/
int gnutls_pubkey_export_ecc_x962(gnutls_pubkey_t key,
          gnutls_datum_t *parameters,
          gnutls_datum_t *ecpoint)
{
  int ret;
  gnutls_datum_t raw_point = { NULL, 0 };

  if (key == NULL || key->params.algo != GNUTLS_PK_EC)
    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

  ret = _gnutls_x509_write_ecc_pubkey(&key->params, &raw_point);
  if (ret < 0)
    return gnutls_assert_val(ret);

  ret = _gnutls_x509_encode_string(ASN1_ETYPE_OCTET_STRING,
           raw_point.data, raw_point.size,
           ecpoint);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  ret = _gnutls_x509_write_ecc_params(key->params.curve, parameters);
  if (ret < 0) {
    _gnutls_free_datum(ecpoint);
    gnutls_assert();
    goto cleanup;
  }

  ret = 0;
cleanup:
  gnutls_free(raw_point.data);
  return ret;
}

/**
 * gnutls_pubkey_export_gost_raw2:
 * @key: Holds the public key
 * @curve: will hold the curve (may be %NULL)
 * @digest: will hold the curve (may be %NULL)
 * @paramset: will hold the parameters id (may be %NULL)
 * @x: will hold the x-coordinate (may be %NULL)
 * @y: will hold the y-coordinate (may be %NULL)
 * @flags: flags from %gnutls_abstract_export_flags_t
 *
 * This function will export the GOST public key's parameters found in
 * the given key.  The new parameters will be allocated using
 * gnutls_malloc() and will be stored in the appropriate datum.
 *
 * Note: parameters will be stored with least significant byte first. On
 * version 3.6.3 this was incorrectly returned in big-endian format.
 *
 * Returns: %GNUTLS_E_SUCCESS on success, otherwise a negative error code.
 *
 * Since: 3.6.3
 **/
int gnutls_pubkey_export_gost_raw2(gnutls_pubkey_t key,
           gnutls_ecc_curve_t *curve,
           gnutls_digest_algorithm_t *digest,
           gnutls_gost_paramset_t *paramset,
           gnutls_datum_t *x, gnutls_datum_t *y,
           unsigned int flags)
{
  int ret;

  mpi_dprint_func dprint = _gnutls_mpi_dprint_le;

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

  if (key->params.algo != GNUTLS_PK_GOST_01 &&
      key->params.algo != GNUTLS_PK_GOST_12_256 &&
      key->params.algo != GNUTLS_PK_GOST_12_512) {
    gnutls_assert();
    return GNUTLS_E_INVALID_REQUEST;
  }

  if (curve)
    *curve = key->params.curve;

  if (digest)
    *digest = _gnutls_gost_digest(key->params.algo);

  if (paramset)
    *paramset = key->params.gost_params;

  /* X */
  if (x) {
    ret = dprint(key->params.params[GOST_X], x);
    if (ret < 0) {
      gnutls_assert();
      return ret;
    }
  }

  /* Y */
  if (y) {
    ret = dprint(key->params.params[GOST_Y], y);
    if (ret < 0) {
      gnutls_assert();
      _gnutls_free_datum(x);
      return ret;
    }
  }

  return 0;
}

/**
 * gnutls_pubkey_import:
 * @key: The public key. 
 * @data: The DER or PEM encoded certificate. 
 * @format: One of DER or PEM 
 * 
 * This function will import the provided public key in
 * a SubjectPublicKeyInfo X.509 structure to a native
 * %gnutls_pubkey_t type. The output will be stored 
 * in @key. If the public key is PEM encoded it should have a header 
 * of "PUBLIC KEY". 
 * 
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 * negative error value.
 *
 * Since: 2.12.0
 **/
int gnutls_pubkey_import(gnutls_pubkey_t key, const gnutls_datum_t *data,
       gnutls_x509_crt_fmt_t format)
{
  int result = 0, need_free = 0;
  gnutls_datum_t _data;
  asn1_node spk;

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

  _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 */
    result = _gnutls_fbase64_decode(PEM_PK, data->data, data->size,
            &_data);

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

    need_free = 1;
  }

  if ((result = asn1_create_element(_gnutls_get_pkix(),
            "PKIX1.SubjectPublicKeyInfo",
            &spk)) != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto cleanup;
  }

  result = _asn1_strict_der_decode(&spk, _data.data, _data.size, NULL);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto cleanup;
  }

  result = _gnutls_get_asn_mpis(spk, "", &key->params);
  if (result < 0) {
    gnutls_assert();
    goto cleanup;
  }

  key->bits = pubkey_to_bits(&key->params);
  result = 0;

cleanup:
  asn1_delete_structure(&spk);

  if (need_free)
    _gnutls_free_datum(&_data);
  return result;
}

/**
 * gnutls_x509_crt_set_pubkey:
 * @crt: should contain a #gnutls_x509_crt_t type
 * @key: holds a public key
 *
 * This function will set the public parameters from the given public
 * key to the certificate. The @key can be deallocated after that.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 2.12.0
 **/
int gnutls_x509_crt_set_pubkey(gnutls_x509_crt_t crt, gnutls_pubkey_t key)
{
  int result;

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

  result = _gnutls_x509_encode_and_copy_PKI_params(
    crt->cert, "tbsCertificate.subjectPublicKeyInfo", &key->params);

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

  if (key->key_usage)
    gnutls_x509_crt_set_key_usage(crt, key->key_usage);

  return 0;
}

/**
 * gnutls_x509_crq_set_pubkey:
 * @crq: should contain a #gnutls_x509_crq_t type
 * @key: holds a public key
 *
 * This function will set the public parameters from the given public
 * key to the request. The @key can be deallocated after that.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 2.12.0
 **/
int gnutls_x509_crq_set_pubkey(gnutls_x509_crq_t crq, gnutls_pubkey_t key)
{
  int result;

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

  result = _gnutls_x509_encode_and_copy_PKI_params(
    crq->crq, "certificationRequestInfo.subjectPKInfo",
    &key->params);

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

  if (key->key_usage)
    gnutls_x509_crq_set_key_usage(crq, key->key_usage);

  return 0;
}

/**
 * gnutls_pubkey_set_key_usage:
 * @key: a certificate of type #gnutls_x509_crt_t
 * @usage: an ORed sequence of the GNUTLS_KEY_* elements.
 *
 * This function will set the key usage flags of the public key. This
 * is only useful if the key is to be exported to a certificate or
 * certificate request.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 2.12.0
 **/
int gnutls_pubkey_set_key_usage(gnutls_pubkey_t key, unsigned int usage)
{
  key->key_usage = usage;

  return 0;
}

#ifdef ENABLE_PKCS11

#if 0
/**
 * gnutls_pubkey_import_pkcs11_url:
 * @key: A key of type #gnutls_pubkey_t
 * @url: A PKCS 11 url
 * @flags: One of GNUTLS_PKCS11_OBJ_* flags
 *
 * This function will import a PKCS 11 certificate to a #gnutls_pubkey_t
 * structure.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 2.12.0
 **/
int
gnutls_pubkey_import_pkcs11_url(gnutls_pubkey_t key, const char *url,
        unsigned int flags)
{
  int x;
}
#endif

static int _gnutls_pubkey_import_pkcs11_url(gnutls_pubkey_t key,
              const char *url, unsigned int flags)
{
  gnutls_pkcs11_obj_t pcrt;
  int ret;

  ret = gnutls_pkcs11_obj_init(&pcrt);
  if (ret < 0) {
    gnutls_assert();
    return ret;
  }

  if (key->pin.cb)
    gnutls_pkcs11_obj_set_pin_function(pcrt, key->pin.cb,
               key->pin.data);

  ret = gnutls_pkcs11_obj_import_url(
    pcrt, url, flags | GNUTLS_PKCS11_OBJ_FLAG_EXPECT_PUBKEY);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  ret = gnutls_pubkey_import_pkcs11(key, pcrt, flags);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  ret = 0;
cleanup:

  gnutls_pkcs11_obj_deinit(pcrt);

  return ret;
}

#endif /* ENABLE_PKCS11 */

/**
 * gnutls_pubkey_import_url:
 * @key: A key of type #gnutls_pubkey_t
 * @url: A PKCS 11 url
 * @flags: One of GNUTLS_PKCS11_OBJ_* flags
 *
 * This function will import a public key from the provided URL.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.1.0
 **/
int gnutls_pubkey_import_url(gnutls_pubkey_t key, const char *url,
           unsigned int flags)
{
  unsigned i;

  for (i = 0; i < _gnutls_custom_urls_size; i++) {
    if (strncmp(url, _gnutls_custom_urls[i].name,
          _gnutls_custom_urls[i].name_size) == 0) {
      if (_gnutls_custom_urls[i].import_pubkey)
        return _gnutls_custom_urls[i].import_pubkey(
          key, url, flags);
    }
  }

  if (strncmp(url, PKCS11_URL, PKCS11_URL_SIZE) == 0)
#ifdef ENABLE_PKCS11
    return _gnutls_pubkey_import_pkcs11_url(key, url, flags);
#else
    return gnutls_assert_val(GNUTLS_E_UNIMPLEMENTED_FEATURE);
#endif

  if (strncmp(url, TPMKEY_URL, TPMKEY_URL_SIZE) == 0)
#ifdef HAVE_TROUSERS
    return gnutls_pubkey_import_tpm_url(key, url, NULL, 0);
#else
    return gnutls_assert_val(GNUTLS_E_UNIMPLEMENTED_FEATURE);
#endif

  return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
}

/**
 * gnutls_pubkey_import_rsa_raw:
 * @key: The key
 * @m: holds the modulus
 * @e: holds the public exponent
 *
 * This function will replace the parameters in the given structure.
 * The new parameters should be stored in the appropriate
 * gnutls_datum.
 *
 * Returns: %GNUTLS_E_SUCCESS on success, or an negative error code.
 *
 * Since: 2.12.0
 **/
int gnutls_pubkey_import_rsa_raw(gnutls_pubkey_t key, const gnutls_datum_t *m,
         const gnutls_datum_t *e)
{
  if (key == NULL) {
    gnutls_assert();
    return GNUTLS_E_INVALID_REQUEST;
  }

  gnutls_pk_params_release(&key->params);
  gnutls_pk_params_init(&key->params);

  if (_gnutls_mpi_init_scan_nz(&key->params.params[0], m->data,
             m->size)) {
    gnutls_assert();
    return GNUTLS_E_MPI_SCAN_FAILED;
  }

  if (_gnutls_mpi_init_scan_nz(&key->params.params[1], e->data,
             e->size)) {
    gnutls_assert();
    _gnutls_mpi_release(&key->params.params[0]);
    return GNUTLS_E_MPI_SCAN_FAILED;
  }

  key->params.params_nr = RSA_PUBLIC_PARAMS;
  key->params.algo = GNUTLS_PK_RSA;
  key->bits = pubkey_to_bits(&key->params);

  return 0;
}

/**
 * gnutls_pubkey_import_ecc_raw:
 * @key: The structure to store the parsed key
 * @curve: holds the curve
 * @x: holds the x-coordinate
 * @y: holds the y-coordinate
 *
 * This function will convert the given elliptic curve parameters to a
 * #gnutls_pubkey_t.  The output will be stored in @key.
 *
 * In EdDSA curves the @y parameter should be %NULL and the @x parameter must
 * be the value in the native format for the curve.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.0
 **/
int gnutls_pubkey_import_ecc_raw(gnutls_pubkey_t key, gnutls_ecc_curve_t curve,
         const gnutls_datum_t *x,
         const gnutls_datum_t *y)
{
  int ret;

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

  gnutls_pk_params_release(&key->params);
  gnutls_pk_params_init(&key->params);

  if (curve_is_eddsa(curve) || curve_is_modern_ecdh(curve)) {
    unsigned size = gnutls_ecc_curve_get_size(curve);
    if (x->size != size) {
      ret = gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
      goto cleanup;
    }

    ret = _gnutls_set_datum(&key->params.raw_pub, x->data, x->size);
    if (ret < 0) {
      gnutls_assert();
      goto cleanup;
    }

    switch (curve) {
    case GNUTLS_ECC_CURVE_ED25519:
      key->params.algo = GNUTLS_PK_EDDSA_ED25519;
      break;
    case GNUTLS_ECC_CURVE_ED448:
      key->params.algo = GNUTLS_PK_EDDSA_ED448;
      break;
    case GNUTLS_ECC_CURVE_X25519:
      key->params.algo = GNUTLS_PK_ECDH_X25519;
      break;
    case GNUTLS_ECC_CURVE_X448:
      key->params.algo = GNUTLS_PK_ECDH_X448;
      break;
    default:
      break;
    }
    key->params.curve = curve;
    key->bits = pubkey_to_bits(&key->params);

    return 0;
  }

  /* ECDSA */
  if (y == NULL) {
    gnutls_assert();
    return GNUTLS_E_INVALID_REQUEST;
  }

  key->params.curve = curve;

  if (_gnutls_mpi_init_scan_nz(&key->params.params[ECC_X], x->data,
             x->size)) {
    gnutls_assert();
    ret = GNUTLS_E_MPI_SCAN_FAILED;
    goto cleanup;
  }
  key->params.params_nr++;

  if (_gnutls_mpi_init_scan_nz(&key->params.params[ECC_Y], y->data,
             y->size)) {
    gnutls_assert();
    ret = GNUTLS_E_MPI_SCAN_FAILED;
    goto cleanup;
  }
  key->params.params_nr++;
  key->params.algo = GNUTLS_PK_ECDSA;
  key->bits = pubkey_to_bits(&key->params);

  return 0;

cleanup:
  gnutls_pk_params_release(&key->params);
  return ret;
}

/**
 * gnutls_pubkey_import_ecc_x962:
 * @key: The structure to store the parsed key
 * @parameters: DER encoding of an ANSI X9.62 parameters
 * @ecpoint: DER encoding of ANSI X9.62 ECPoint
 *
 * This function will convert the given elliptic curve parameters to a
 * #gnutls_pubkey_t.  The output will be stored in @key.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.0
 **/
int gnutls_pubkey_import_ecc_x962(gnutls_pubkey_t key,
          const gnutls_datum_t *parameters,
          const gnutls_datum_t *ecpoint)
{
  int ret;
  gnutls_datum_t raw_point = { NULL, 0 };

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

  gnutls_pk_params_release(&key->params);
  gnutls_pk_params_init(&key->params);

  key->params.params_nr = 0;

  ret = _gnutls_x509_read_ecc_params(parameters->data, parameters->size,
             &key->params.curve);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  ret = _gnutls_x509_decode_string(ASN1_ETYPE_OCTET_STRING, ecpoint->data,
           ecpoint->size, &raw_point, 0);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  ret = _gnutls_ecc_ansi_x962_import(raw_point.data, raw_point.size,
             &key->params.params[ECC_X],
             &key->params.params[ECC_Y]);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }
  key->params.params_nr += 2;
  key->params.algo = GNUTLS_PK_EC;

  gnutls_free(raw_point.data);
  return 0;

cleanup:
  gnutls_pk_params_release(&key->params);
  gnutls_free(raw_point.data);
  return ret;
}

/**
 * gnutls_pubkey_import_gost_raw:
 * @key: The structure to store the parsed key
 * @curve: holds the curve
 * @digest: holds the digest
 * @paramset: holds the parameters id
 * @x: holds the x-coordinate
 * @y: holds the y-coordinate
 *
 * This function will convert the given GOST public key's parameters to a
 * #gnutls_pubkey_t.  The output will be stored in @key.  @digest should be
 * one of GNUTLS_DIG_GOSR_94, GNUTLS_DIG_STREEBOG_256 or
 * GNUTLS_DIG_STREEBOG_512.  If @paramset is set to GNUTLS_GOST_PARAMSET_UNKNOWN
 * default one will be selected depending on @digest.
 *
 * Note: parameters should be stored with least significant byte first. On
 * version 3.6.3 big-endian format was used incorrectly.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.6.3
 **/
int gnutls_pubkey_import_gost_raw(gnutls_pubkey_t key, gnutls_ecc_curve_t curve,
          gnutls_digest_algorithm_t digest,
          gnutls_gost_paramset_t paramset,
          const gnutls_datum_t *x,
          const gnutls_datum_t *y)
{
  int ret;
  gnutls_pk_algorithm_t pk_algo;

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

  pk_algo = _gnutls_digest_gost(digest);
  if (pk_algo == GNUTLS_PK_UNKNOWN)
    return GNUTLS_E_ILLEGAL_PARAMETER;

  if (paramset == GNUTLS_GOST_PARAMSET_UNKNOWN)
    paramset = _gnutls_gost_paramset_default(pk_algo);

  gnutls_pk_params_release(&key->params);
  gnutls_pk_params_init(&key->params);

  key->params.curve = curve;
  key->params.gost_params = paramset;

  if (_gnutls_mpi_init_scan_le(&key->params.params[GOST_X], x->data,
             x->size)) {
    gnutls_assert();
    ret = GNUTLS_E_MPI_SCAN_FAILED;
    goto cleanup;
  }
  key->params.params_nr++;

  if (_gnutls_mpi_init_scan_le(&key->params.params[GOST_Y], y->data,
             y->size)) {
    gnutls_assert();
    ret = GNUTLS_E_MPI_SCAN_FAILED;
    goto cleanup;
  }
  key->params.params_nr++;
  key->params.algo = pk_algo;

  return 0;

cleanup:
  gnutls_pk_params_release(&key->params);
  return ret;
}

/**
 * gnutls_pubkey_import_dsa_raw:
 * @key: The structure to store the parsed key
 * @p: holds the p
 * @q: holds the q
 * @g: holds the g
 * @y: holds the y
 *
 * This function will convert the given DSA raw parameters to the
 * native #gnutls_pubkey_t format.  The output will be stored
 * in @key.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 2.12.0
 **/
int gnutls_pubkey_import_dsa_raw(gnutls_pubkey_t key, const gnutls_datum_t *p,
         const gnutls_datum_t *q,
         const gnutls_datum_t *g,
         const gnutls_datum_t *y)
{
  int ret;

  if (unlikely(key == NULL || p == NULL || q == NULL || g == NULL ||
         y == NULL)) {
    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
  }

  gnutls_pk_params_release(&key->params);
  gnutls_pk_params_init(&key->params);

  if (_gnutls_mpi_init_scan_nz(&key->params.params[DSA_P], p->data,
             p->size)) {
    gnutls_assert();
    ret = GNUTLS_E_MPI_SCAN_FAILED;
    goto cleanup;
  }

  if (_gnutls_mpi_init_scan_nz(&key->params.params[DSA_Q], q->data,
             q->size)) {
    gnutls_assert();
    ret = GNUTLS_E_MPI_SCAN_FAILED;
    goto cleanup;
  }

  if (_gnutls_mpi_init_scan_nz(&key->params.params[DSA_G], g->data,
             g->size)) {
    gnutls_assert();
    ret = GNUTLS_E_MPI_SCAN_FAILED;
    goto cleanup;
  }

  if (_gnutls_mpi_init_scan_nz(&key->params.params[DSA_Y], y->data,
             y->size)) {
    gnutls_assert();
    ret = GNUTLS_E_MPI_SCAN_FAILED;
    goto cleanup;
  }

  key->params.params_nr = DSA_PUBLIC_PARAMS;
  key->params.algo = GNUTLS_PK_DSA;
  key->bits = pubkey_to_bits(&key->params);

  return 0;

cleanup:
  gnutls_pk_params_clear(&key->params);
  gnutls_pk_params_release(&key->params);

  return ret;
}

/**
 * gnutls_pubkey_import_dh_raw:
 * @key: The structure to store the parsed key
 * @params: holds the %gnutls_dh_params_t
 * @y: holds the y
 *
 * This function will convert the given Diffie-Hellman raw parameters
 * to the native #gnutls_pubkey_t format.  The output will be stored
 * in @key.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.8.2
 **/
int gnutls_pubkey_import_dh_raw(gnutls_pubkey_t key,
        const gnutls_dh_params_t params,
        const gnutls_datum_t *y)
{
  int ret;

  if (unlikely(key == NULL || params == NULL || y == NULL)) {
    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
  }

  gnutls_pk_params_release(&key->params);
  gnutls_pk_params_init(&key->params);

  key->params.params[DH_P] = _gnutls_mpi_copy(params->params[0]);
  key->params.params[DH_G] = _gnutls_mpi_copy(params->params[1]);
  if (params->params[2]) {
    key->params.params[DH_Q] = _gnutls_mpi_copy(params->params[2]);
  }
  key->params.qbits = params->q_bits;
  key->params.params_nr = DH_PUBLIC_PARAMS;

  if (_gnutls_mpi_init_scan_nz(&key->params.params[DH_Y], y->data,
             y->size)) {
    gnutls_assert();
    ret = GNUTLS_E_MPI_SCAN_FAILED;
    goto cleanup;
  }

  key->params.algo = GNUTLS_PK_DH;
  key->bits = pubkey_to_bits(&key->params);

  return 0;

cleanup:
  gnutls_pk_params_clear(&key->params);
  gnutls_pk_params_release(&key->params);
  return ret;
}

/* Updates the gnutls_x509_spki_st parameters based on the signature
 * information, and reports any incompatibilities between the existing
 * parameters (if any) with the signature algorithm */
static int fixup_spki_params(const gnutls_pk_params_st *key_params,
           const gnutls_sign_entry_st *se,
           const mac_entry_st *me,
           gnutls_x509_spki_st *params)
{
  unsigned bits;

  if (se->pk != key_params->algo) {
    if (!sign_supports_priv_pk_algorithm(se, key_params->algo)) {
      _gnutls_debug_log("have key: %s/%d, with sign %s/%d\n",
            gnutls_pk_get_name(key_params->algo),
            key_params->algo, se->name, se->id);
      return gnutls_assert_val(GNUTLS_E_CONSTRAINT_ERROR);
    }
  }

  if (params->pk == GNUTLS_PK_RSA_PSS) {
    int ret;
    if (!GNUTLS_PK_IS_RSA(key_params->algo))
      return gnutls_assert_val(GNUTLS_E_CONSTRAINT_ERROR);

    /* The requested sign algorithm is RSA-PSS, while the
     * pubkey doesn't include parameter information. Fill
     * it with the same way as gnutls_privkey_sign*. */
    if (key_params->algo == GNUTLS_PK_RSA ||
        params->rsa_pss_dig == 0) {
      bits = pubkey_to_bits(key_params);
      params->rsa_pss_dig = se->hash;
      ret = _gnutls_find_rsa_pss_salt_size(bits, me, 0);
      if (ret < 0)
        return gnutls_assert_val(ret);

      params->salt_size = ret;
    }

    if (params->rsa_pss_dig != se->hash)
      return gnutls_assert_val(GNUTLS_E_CONSTRAINT_ERROR);
  } else if (params->pk == GNUTLS_PK_DSA ||
       params->pk == GNUTLS_PK_ECDSA) {
    params->dsa_dig = se->hash;
  }

  return 0;
}

/**
 * gnutls_pubkey_verify_data2:
 * @pubkey: Holds the public key
 * @algo: The signature algorithm used
 * @flags: Zero or an OR list of #gnutls_certificate_verify_flags
 * @data: holds the signed data
 * @signature: contains the signature
 *
 * This function will verify the given signed data, using the
 * parameters from the certificate.
 *
 * Returns: In case of a verification failure %GNUTLS_E_PK_SIG_VERIFY_FAILED 
 * is returned, and zero or positive code on success. For known to be insecure
 * signatures this function will return %GNUTLS_E_INSUFFICIENT_SECURITY unless
 * the flag %GNUTLS_VERIFY_ALLOW_BROKEN is specified.
 *
 * Since: 3.0
 **/
int gnutls_pubkey_verify_data2(gnutls_pubkey_t pubkey,
             gnutls_sign_algorithm_t algo, unsigned int flags,
             const gnutls_datum_t *data,
             const gnutls_datum_t *signature)
{
  int ret;
  const mac_entry_st *me;
  gnutls_x509_spki_st params;
  const gnutls_sign_entry_st *se;

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

  if (flags & GNUTLS_VERIFY_USE_TLS1_RSA)
    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

  se = _gnutls_sign_to_entry(algo);
  if (se == NULL)
    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

  ret = pubkey_supports_sig(pubkey, se);
  if (ret < 0)
    return gnutls_assert_val(ret);

  me = hash_to_entry(se->hash);
  if (me == NULL && !_gnutls_pk_is_not_prehashed(se->pk))
    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

  ret = _gnutls_x509_spki_copy(&params, &pubkey->params.spki);
  if (ret < 0)
    return gnutls_assert_val(ret);

  params.pk = se->pk;
  if (flags & GNUTLS_VERIFY_RSA_PSS_FIXED_SALT_LENGTH) {
    params.flags |= GNUTLS_PK_FLAG_RSA_PSS_FIXED_SALT_LENGTH;
  }

  ret = pubkey_verify_data(se, me, data, signature, &pubkey->params,
         &params, flags);
  if (ret < 0) {
    gnutls_assert();
    _gnutls_x509_spki_clear(&params);
    return ret;
  }

  _gnutls_x509_spki_clear(&params);
  return 0;
}

/**
 * gnutls_pubkey_verify_hash2:
 * @key: Holds the public key
 * @algo: The signature algorithm used
 * @flags: Zero or an OR list of #gnutls_certificate_verify_flags
 * @hash: holds the hash digest to be verified
 * @signature: contains the signature
 *
 * This function will verify the given signed digest, using the
 * parameters from the public key. Note that unlike gnutls_privkey_sign_hash(),
 * this function accepts a signature algorithm instead of a digest algorithm.
 * You can use gnutls_pk_to_sign() to get the appropriate value.
 *
 * Returns: In case of a verification failure %GNUTLS_E_PK_SIG_VERIFY_FAILED 
 * is returned, and zero or positive code on success. For known to be insecure
 * signatures this function will return %GNUTLS_E_INSUFFICIENT_SECURITY unless
 * the flag %GNUTLS_VERIFY_ALLOW_BROKEN is specified.
 *
 * Since: 3.0
 **/
int gnutls_pubkey_verify_hash2(gnutls_pubkey_t key,
             gnutls_sign_algorithm_t algo, unsigned int flags,
             const gnutls_datum_t *hash,
             const gnutls_datum_t *signature)
{
  const mac_entry_st *me;
  gnutls_x509_spki_st params;
  const gnutls_sign_entry_st *se;
  int ret;

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

  if (_gnutls_pk_is_not_prehashed(key->params.algo)) {
    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
  }

  ret = _gnutls_x509_spki_copy(&params, &key->params.spki);
  if (ret < 0)
    return gnutls_assert_val(ret);

  if (flags & GNUTLS_VERIFY_USE_TLS1_RSA) {
    if (!GNUTLS_PK_IS_RSA(key->params.algo)) {
      gnutls_assert();
      ret = GNUTLS_E_INCOMPATIBLE_SIG_WITH_KEY;
      goto cleanup;
    }
    params.pk = GNUTLS_PK_RSA;
    /* we do not check for insecure algorithms with this flag */
    ret = _gnutls_pk_verify(params.pk, hash, signature,
          &key->params, &params);
    if (ret < 0) {
      gnutls_assert();
      goto cleanup;
    }
  } else {
    se = _gnutls_sign_to_entry(algo);
    if (se == NULL) {
      gnutls_assert();
      ret = GNUTLS_E_INVALID_REQUEST;
      goto cleanup;
    }

    ret = pubkey_supports_sig(key, se);
    if (ret < 0) {
      gnutls_assert();
      goto cleanup;
    }

    params.pk = se->pk;

    me = hash_to_entry(se->hash);
    if (me == NULL && !_gnutls_pk_is_not_prehashed(se->pk)) {
      gnutls_assert();
      ret = GNUTLS_E_INVALID_REQUEST;
      goto cleanup;
    }

    ret = pubkey_verify_hashed_data(se, me, hash, signature,
            &key->params, &params, flags);
    if (ret < 0) {
      gnutls_assert();
      goto cleanup;
    }
  }

cleanup:
  _gnutls_x509_spki_clear(&params);
  return ret;
}

/**
 * gnutls_pubkey_encrypt_data:
 * @key: Holds the public key
 * @flags: should be 0 for now
 * @plaintext: The data to be encrypted
 * @ciphertext: contains the encrypted data
 *
 * This function will encrypt the given data, using the public
 * key. On success the @ciphertext will be allocated using gnutls_malloc().
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.0
 **/
int gnutls_pubkey_encrypt_data(gnutls_pubkey_t key, unsigned int flags,
             const gnutls_datum_t *plaintext,
             gnutls_datum_t *ciphertext)
{
  if (key == NULL) {
    gnutls_assert();
    return GNUTLS_E_INVALID_REQUEST;
  }

  return _gnutls_pk_encrypt(key->params.algo, ciphertext, plaintext,
          &key->params);
}

static int pubkey_supports_sig(gnutls_pubkey_t pubkey,
             const gnutls_sign_entry_st *se)
{
  if (pubkey->params.algo == GNUTLS_PK_ECDSA && se->curve) {
    gnutls_ecc_curve_t curve = pubkey->params.curve;

    if (curve != se->curve) {
      _gnutls_handshake_log(
        "have key: ECDSA with %s/%d, with sign %s/%d\n",
        gnutls_ecc_curve_get_name(curve), (int)curve,
        se->name, se->id);
      return gnutls_assert_val(
        GNUTLS_E_INCOMPATIBLE_SIG_WITH_KEY);
    }
  }

  if (se->pk !=
      pubkey->params
        .algo) { /* if the PK algorithm of the signature differs to the one on the pubkey */
    if (!sign_supports_priv_pk_algorithm(se, pubkey->params.algo)) {
      _gnutls_handshake_log(
        "have key: %s/%d, with sign %s/%d\n",
        gnutls_pk_get_name(pubkey->params.algo),
        pubkey->params.algo, se->name, se->id);
      return gnutls_assert_val(
        GNUTLS_E_INCOMPATIBLE_SIG_WITH_KEY);
    }
  }

  return 0;
}

/* Checks whether the public key given is compatible with the
 * signature algorithm used. The session is only used for audit logging, and
 * it may be null.
 */
int _gnutls_pubkey_compatible_with_sig(gnutls_session_t session,
               gnutls_pubkey_t pubkey,
               const version_entry_st *ver,
               gnutls_sign_algorithm_t sign)
{
  unsigned int hash_size = 0;
  unsigned int sig_hash_size;
  const mac_entry_st *me;
  const gnutls_sign_entry_st *se;
  int ret;

  se = _gnutls_sign_to_entry(sign);
  if (se != NULL) {
    ret = pubkey_supports_sig(pubkey, se);
    if (ret < 0)
      return gnutls_assert_val(ret);
  } else if (_gnutls_version_has_selectable_sighash(ver)) {
    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
  }

  if (pubkey->params.algo == GNUTLS_PK_DSA) {
    me = _gnutls_dsa_q_to_hash(&pubkey->params, &hash_size);

    /* DSA keys over 1024 bits cannot be used with TLS 1.x, x<2 */
    if (!_gnutls_version_has_selectable_sighash(ver)) {
      if (me->id != GNUTLS_MAC_SHA1)
        return gnutls_assert_val(
          GNUTLS_E_INCOMPAT_DSA_KEY_WITH_TLS_PROTOCOL);
    } else if (se != NULL) {
      me = hash_to_entry(se->hash);

      sig_hash_size = _gnutls_hash_get_algo_len(me);
      if (sig_hash_size < hash_size)
        _gnutls_audit_log(
          session,
          "The hash size used in signature (%u) is less than the expected (%u)\n",
          sig_hash_size, hash_size);
    }

  } else if (pubkey->params.algo == GNUTLS_PK_ECDSA) {
    if (_gnutls_version_has_selectable_sighash(ver) && se != NULL) {
      _gnutls_dsa_q_to_hash(&pubkey->params, &hash_size);

      me = hash_to_entry(se->hash);

      sig_hash_size = _gnutls_hash_get_algo_len(me);

      if (sig_hash_size < hash_size)
        _gnutls_audit_log(
          session,
          "The hash size used in signature (%u) is less than the expected (%u)\n",
          sig_hash_size, hash_size);
    }

  } else if (pubkey->params.algo == GNUTLS_PK_GOST_01 ||
       pubkey->params.algo == GNUTLS_PK_GOST_12_256 ||
       pubkey->params.algo == GNUTLS_PK_GOST_12_512) {
    if (_gnutls_version_has_selectable_sighash(ver) && se != NULL) {
      if (_gnutls_gost_digest(pubkey->params.algo) !=
          se->hash) {
        _gnutls_audit_log(
          session,
          "The hash algo used in signature (%u) is not expected (%u)\n",
          se->hash,
          _gnutls_gost_digest(
            pubkey->params.algo));
        return gnutls_assert_val(
          GNUTLS_E_CONSTRAINT_ERROR);
      }
    }

  } else if (pubkey->params.algo == GNUTLS_PK_RSA_PSS) {
    if (!_gnutls_version_has_selectable_sighash(ver))
      /* this should not have happened */
      return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);

    /* RSA PSS public keys are restricted to a single digest, i.e., signature */

    if (pubkey->params.spki.rsa_pss_dig &&
        pubkey->params.spki.rsa_pss_dig != se->hash) {
      return gnutls_assert_val(GNUTLS_E_CONSTRAINT_ERROR);
    }
  }

  return 0;
}

/* Returns the public key. 
 */
int _gnutls_pubkey_get_mpis(gnutls_pubkey_t key, gnutls_pk_params_st *params)
{
  return _gnutls_pk_params_copy(params, &key->params);
}

/* if hash==MD5 then we do RSA-MD5
 * if hash==SHA then we do RSA-SHA
 * params[0] is modulus
 * params[1] is public key
 */
static int _pkcs1_rsa_verify_sig(gnutls_pk_algorithm_t pk,
         const mac_entry_st *me,
         const gnutls_datum_t *text,
         const gnutls_datum_t *prehash,
         const gnutls_datum_t *signature,
         gnutls_pk_params_st *params,
         gnutls_x509_spki_st *sign_params)
{
  int ret;
  uint8_t md[MAX_HASH_SIZE], *cmp;
  unsigned int digest_size;
  gnutls_datum_t d, di;

  if (unlikely(me == NULL))
    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

  digest_size = _gnutls_hash_get_algo_len(me);
  if (prehash) {
    if (prehash->data == NULL || prehash->size != digest_size)
      return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

    cmp = prehash->data;
  } else {
    if (!text) {
      gnutls_assert();
      return GNUTLS_E_INVALID_REQUEST;
    }

    ret = _gnutls_hash_fast((gnutls_digest_algorithm_t)me->id,
          text->data, text->size, md);
    if (ret < 0) {
      gnutls_assert();
      return ret;
    }

    cmp = md;
  }

  d.data = cmp;
  d.size = digest_size;

  if (pk == GNUTLS_PK_RSA) {
    /* SHA-1 is allowed for SigVer in FIPS 140-3 in legacy
     * mode */
    switch (me->id) {
    case GNUTLS_MAC_SHA1:
    case GNUTLS_MAC_SHA256:
    case GNUTLS_MAC_SHA384:
    case GNUTLS_MAC_SHA512:
    case GNUTLS_MAC_SHA224:
      break;
    default:
      _gnutls_switch_fips_state(
        GNUTLS_FIPS140_OP_NOT_APPROVED);
    }

    /* decrypted is a BER encoded data of type DigestInfo
     */
    ret = encode_ber_digest_info(me, &d, &di);
    if (ret < 0)
      return gnutls_assert_val(ret);

    ret = _gnutls_pk_verify(pk, &di, signature, params,
          sign_params);
    _gnutls_free_datum(&di);
  } else {
    ret = _gnutls_pk_verify(pk, &d, signature, params, sign_params);
  }

  return ret;
}

/* Hashes input data and verifies a signature.
 */
static int dsa_verify_hashed_data(gnutls_pk_algorithm_t pk,
          const mac_entry_st *algo,
          const gnutls_datum_t *hash,
          const gnutls_datum_t *signature,
          gnutls_pk_params_st *params,
          gnutls_x509_spki_st *sign_params)
{
  gnutls_datum_t digest;
  unsigned int hash_len;

  if (algo == NULL)
    algo = _gnutls_dsa_q_to_hash(params, &hash_len);
  else
    hash_len = _gnutls_hash_get_algo_len(algo);

  /* SHA1 or better allowed */
  if (!hash->data || hash->size < hash_len) {
    gnutls_assert();
    _gnutls_debug_log(
      "Hash size (%d) does not correspond to hash %s(%d) or better.\n",
      (int)hash->size, _gnutls_mac_get_name(algo), hash_len);

    if (hash->size != 20) /* SHA1 is allowed */
      return gnutls_assert_val(GNUTLS_E_PK_SIG_VERIFY_FAILED);
  }

  digest.data = hash->data;
  digest.size = hash->size;

  return _gnutls_pk_verify(pk, &digest, signature, params, sign_params);
}

static int dsa_verify_data(gnutls_pk_algorithm_t pk, const mac_entry_st *algo,
         const gnutls_datum_t *data,
         const gnutls_datum_t *signature,
         gnutls_pk_params_st *params,
         gnutls_x509_spki_st *sign_params)
{
  int ret;
  uint8_t _digest[MAX_HASH_SIZE];
  gnutls_datum_t digest;

  if (algo == NULL)
    algo = _gnutls_dsa_q_to_hash(params, NULL);

  ret = _gnutls_hash_fast((gnutls_digest_algorithm_t)algo->id, data->data,
        data->size, _digest);
  if (ret < 0)
    return gnutls_assert_val(ret);

  digest.data = _digest;
  digest.size = _gnutls_hash_get_algo_len(algo);

  return _gnutls_pk_verify(pk, &digest, signature, params, sign_params);
}

/* Verifies the signature data, and returns GNUTLS_E_PK_SIG_VERIFY_FAILED if 
 * not verified, or 1 otherwise.
 */
static int pubkey_verify_hashed_data(const gnutls_sign_entry_st *se,
             const mac_entry_st *me,
             const gnutls_datum_t *hash,
             const gnutls_datum_t *signature,
             gnutls_pk_params_st *params,
             gnutls_x509_spki_st *sign_params,
             unsigned flags)
{
  int ret;

  if (unlikely(me == NULL))
    return gnutls_assert_val(GNUTLS_E_UNKNOWN_HASH_ALGORITHM);

  ret = fixup_spki_params(params, se, me, sign_params);
  if (ret < 0)
    return gnutls_assert_val(ret);

  switch (se->pk) {
  case GNUTLS_PK_RSA:
  case GNUTLS_PK_RSA_PSS:

    if (_pkcs1_rsa_verify_sig(se->pk, me, NULL, hash, signature,
            params, sign_params) != 0) {
      gnutls_assert();
      return GNUTLS_E_PK_SIG_VERIFY_FAILED;
    }

    break;

  case GNUTLS_PK_ECDSA:
  case GNUTLS_PK_GOST_01:
  case GNUTLS_PK_GOST_12_256:
  case GNUTLS_PK_GOST_12_512:
  case GNUTLS_PK_DSA:
    if (dsa_verify_hashed_data(se->pk, me, hash, signature, params,
             sign_params) != 0) {
      gnutls_assert();
      return GNUTLS_E_PK_SIG_VERIFY_FAILED;
    }

    break;
  default:
    gnutls_assert();
    return GNUTLS_E_INVALID_REQUEST;
  }

  if (_gnutls_sign_is_secure2(se, 0) == 0 &&
      _gnutls_is_broken_sig_allowed(se, flags) == 0) {
    return gnutls_assert_val(GNUTLS_E_INSUFFICIENT_SECURITY);
  }

  return 1;
}

/* Verifies the signature data, and returns GNUTLS_E_PK_SIG_VERIFY_FAILED if 
 * not verified, or 1 otherwise.
 */
int pubkey_verify_data(const gnutls_sign_entry_st *se, const mac_entry_st *me,
           const gnutls_datum_t *data,
           const gnutls_datum_t *signature,
           gnutls_pk_params_st *params,
           gnutls_x509_spki_st *sign_params, unsigned flags)
{
  int ret;

  if (unlikely(me == NULL))
    return gnutls_assert_val(GNUTLS_E_UNKNOWN_HASH_ALGORITHM);

  ret = fixup_spki_params(params, se, me, sign_params);
  if (ret < 0)
    return gnutls_assert_val(ret);

  switch (se->pk) {
  case GNUTLS_PK_RSA:
  case GNUTLS_PK_RSA_PSS:
    if (_pkcs1_rsa_verify_sig(se->pk, me, data, NULL, signature,
            params, sign_params) != 0) {
      gnutls_assert();
      return GNUTLS_E_PK_SIG_VERIFY_FAILED;
    }

    break;

  case GNUTLS_PK_EDDSA_ED25519:
  case GNUTLS_PK_EDDSA_ED448:
    if (_gnutls_pk_verify(se->pk, data, signature, params,
              sign_params) != 0) {
      gnutls_assert();
      return GNUTLS_E_PK_SIG_VERIFY_FAILED;
    }

    break;

  case GNUTLS_PK_EC:
  case GNUTLS_PK_DSA:
  case GNUTLS_PK_GOST_01:
  case GNUTLS_PK_GOST_12_256:
  case GNUTLS_PK_GOST_12_512:
    if (dsa_verify_data(se->pk, me, data, signature, params,
            sign_params) != 0) {
      gnutls_assert();
      return GNUTLS_E_PK_SIG_VERIFY_FAILED;
    }

    break;
  default:
    gnutls_assert();
    return GNUTLS_E_INVALID_REQUEST;
  }

  if (_gnutls_sign_is_secure2(se, 0) == 0 &&
      _gnutls_is_broken_sig_allowed(se, flags) == 0) {
    return gnutls_assert_val(GNUTLS_E_INSUFFICIENT_SECURITY);
  }

  return 1;
}

const mac_entry_st *_gnutls_dsa_q_to_hash(const gnutls_pk_params_st *params,
            unsigned int *hash_len)
{
  int bits = 0;
  int ret;

  if (params->algo == GNUTLS_PK_DSA)
    bits = _gnutls_mpi_get_nbits(params->params[1]);
  else if (params->algo == GNUTLS_PK_EC)
    bits = gnutls_ecc_curve_get_size(params->curve) * 8;

  if (bits <= 160) {
    if (hash_len)
      *hash_len = 20;
    ret = GNUTLS_DIG_SHA1;
  } else if (bits <= 192) {
    if (hash_len)
      *hash_len = 24;
    ret = GNUTLS_DIG_SHA256;
  } else if (bits <= 224) {
    if (hash_len)
      *hash_len = 28;
    ret = GNUTLS_DIG_SHA256;
  } else if (bits <= 256) {
    if (hash_len)
      *hash_len = 32;
    ret = GNUTLS_DIG_SHA256;
  } else if (bits <= 384) {
    if (hash_len)
      *hash_len = 48;
    ret = GNUTLS_DIG_SHA384;
  } else {
    if (hash_len)
      *hash_len = 64;
    ret = GNUTLS_DIG_SHA512;
  }

  return mac_to_entry(ret);
}

/**
 * gnutls_pubkey_set_pin_function:
 * @key: A key of type #gnutls_pubkey_t
 * @fn: the callback
 * @userdata: data associated with the callback
 *
 * This function will set a callback function to be used when
 * required to access the object. This function overrides any other
 * global PIN functions.
 *
 * Note that this function must be called right after initialization
 * to have effect.
 *
 * Since: 3.1.0
 *
 **/
void gnutls_pubkey_set_pin_function(gnutls_pubkey_t key,
            gnutls_pin_callback_t fn, void *userdata)
{
  key->pin.cb = fn;
  key->pin.data = userdata;
}

/**
 * gnutls_pubkey_import_x509_raw:
 * @pkey: The public key
 * @data: The public key data to be imported
 * @format: The format of the public key
 * @flags: should be zero
 *
 * This function will import the given public key to the abstract
 * #gnutls_pubkey_t type. 
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.1.3
 **/
int gnutls_pubkey_import_x509_raw(gnutls_pubkey_t pkey,
          const gnutls_datum_t *data,
          gnutls_x509_crt_fmt_t format,
          unsigned int flags)
{
  gnutls_x509_crt_t xpriv;
  int ret;

  ret = gnutls_x509_crt_init(&xpriv);
  if (ret < 0)
    return gnutls_assert_val(ret);

  ret = gnutls_x509_crt_import(xpriv, data, format);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  ret = gnutls_pubkey_import_x509(pkey, xpriv, flags);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  ret = 0;

cleanup:
  gnutls_x509_crt_deinit(xpriv);

  return ret;
}

/**
 * gnutls_pubkey_verify_params:
 * @key: should contain a #gnutls_pubkey_t type
 *
 * This function will verify the public key parameters.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.3.0
 **/
int gnutls_pubkey_verify_params(gnutls_pubkey_t key)
{
  int ret;

  ret = _gnutls_pk_verify_pub_params(key->params.algo, &key->params);
  if (ret < 0) {
    gnutls_assert();
    return ret;
  }

  return 0;
}

/**
 * gnutls_pubkey_get_spki:
 * @pubkey: a public key of type #gnutls_pubkey_t
 * @spki: a SubjectPublicKeyInfo structure of type #gnutls_pubkey_spki_t
 * @flags: must be zero
 *
 * This function will return the public key information if available.
 * The provided @spki must be initialized.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.6.0
 **/
int gnutls_pubkey_get_spki(gnutls_pubkey_t pubkey, gnutls_x509_spki_t spki,
         unsigned int flags)
{
  gnutls_x509_spki_t p = &pubkey->params.spki;

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

  if (p->pk == GNUTLS_PK_UNKNOWN)
    return gnutls_assert_val(GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE);

  return _gnutls_x509_spki_copy(spki, p);
}

/**
 * gnutls_pubkey_set_spki:
 * @pubkey: a public key of type #gnutls_pubkey_t
 * @spki: a SubjectPublicKeyInfo structure of type #gnutls_pubkey_spki_t
 * @flags: must be zero
 *
 * This function will set the public key information.
 * The provided @spki must be initialized.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.6.0
 **/
int gnutls_pubkey_set_spki(gnutls_pubkey_t pubkey,
         const gnutls_x509_spki_t spki, unsigned int flags)
{
  int ret;

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

  if (!_gnutls_pk_are_compat(pubkey->params.algo, spki->pk))
    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

  ret = _gnutls_x509_spki_copy(&pubkey->params.spki, spki);
  if (ret < 0)
    return gnutls_assert_val(ret);

  pubkey->params.algo = spki->pk;

  return 0;
}

Coverage Report

Created: 2024-07-23 07:36