path: root/lib/x509/pkcs7.c

/*
 * Copyright (C) 2003-2005, 2008-2010, 2012 Free Software Foundation,
 * Inc.
 *
 * 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 3 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 <http://www.gnu.org/licenses/>
 *
 */

/* Functions that relate on PKCS7 certificate lists parsing.
 */

#include <gnutls_int.h>
#include <libtasn1.h>

#ifdef ENABLE_PKI

#include <gnutls_datum.h>
#include <gnutls_global.h>
#include <gnutls_errors.h>
#include <common.h>
#include <x509_b64.h>

#define SIGNED_DATA_OID "1.2.840.113549.1.7.2"

/* Decodes the PKCS #7 signed data, and returns an ASN1_TYPE, 
 * which holds them. If raw is non null then the raw decoded
 * data are copied (they are locally allocated) there.
 */
static int
_decode_pkcs7_signed_data (ASN1_TYPE pkcs7, ASN1_TYPE * sdata,
                           gnutls_datum_t * raw)
{
  char oid[MAX_OID_SIZE];
  ASN1_TYPE c2;
  uint8_t *tmp = NULL;
  int tmp_size, len, result;

  len = sizeof (oid) - 1;
  result = asn1_read_value (pkcs7, "contentType", oid, &len);
  if (result != ASN1_SUCCESS)
    {
      gnutls_assert ();
      return _gnutls_asn2err (result);
    }

  if (strcmp (oid, SIGNED_DATA_OID) != 0)
    {
      gnutls_assert ();
      _gnutls_debug_log ("Unknown PKCS7 Content OID '%s'\n", oid);
      return GNUTLS_E_UNKNOWN_PKCS_CONTENT_TYPE;
    }

  if ((result = asn1_create_element
       (_gnutls_get_pkix (), "PKIX1.pkcs-7-SignedData", &c2)) != ASN1_SUCCESS)
    {
      gnutls_assert ();
      return _gnutls_asn2err (result);
    }

  /* the Signed-data has been created, so
   * decode them.
   */
  tmp_size = 0;
  result = asn1_read_value (pkcs7, "content", NULL, &tmp_size);
  if (result != ASN1_MEM_ERROR)
    {
      gnutls_assert ();
      result = _gnutls_asn2err (result);
      goto cleanup;
    }

  tmp = gnutls_malloc (tmp_size);
  if (tmp == NULL)
    {
      gnutls_assert ();
      result = GNUTLS_E_MEMORY_ERROR;
      goto cleanup;
    }

  result = asn1_read_value (pkcs7, "content", tmp, &tmp_size);
  if (result != ASN1_SUCCESS)
    {
      gnutls_assert ();
      result = _gnutls_asn2err (result);
      goto cleanup;
    }

  /* tmp, tmp_size hold the data and the size of the CertificateSet structure
   * actually the ANY stuff.
   */

  /* Step 1. In case of a signed structure extract certificate set.
   */

  result = asn1_der_decoding (&c2, tmp, tmp_size, NULL);
  if (result != ASN1_SUCCESS)
    {
      gnutls_assert ();
      result = _gnutls_asn2err (result);
      goto cleanup;
    }

  if (raw == NULL)
    {
      gnutls_free (tmp);
    }
  else
    {
      raw->data = tmp;
      raw->size = tmp_size;
    }

  *sdata = c2;

  return 0;

cleanup:
  if (c2)
    asn1_delete_structure (&c2);
  gnutls_free (tmp);
  return result;
}

/**
 * gnutls_pkcs7_init:
 * @pkcs7: The structure to be initialized
 *
 * This function will initialize a PKCS7 structure. PKCS7 structures
 * usually contain lists of X.509 Certificates and X.509 Certificate
 * revocation lists.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 **/
int
gnutls_pkcs7_init (gnutls_pkcs7_t * pkcs7)
{
  *pkcs7 = gnutls_calloc (1, sizeof (gnutls_pkcs7_int));

  if (*pkcs7)
    {
      int result = asn1_create_element (_gnutls_get_pkix (),
                                        "PKIX1.pkcs-7-ContentInfo",
                                        &(*pkcs7)->pkcs7);
      if (result != ASN1_SUCCESS)
        {
          gnutls_assert ();
          gnutls_free (*pkcs7);
          return _gnutls_asn2err (result);
        }
      return 0;                 /* success */
    }
  return GNUTLS_E_MEMORY_ERROR;
}

/**
 * gnutls_pkcs7_deinit:
 * @pkcs7: The structure to be initialized
 *
 * This function will deinitialize a PKCS7 structure.
 **/
void
gnutls_pkcs7_deinit (gnutls_pkcs7_t pkcs7)
{
  if (!pkcs7)
    return;

  if (pkcs7->pkcs7)
    asn1_delete_structure (&pkcs7->pkcs7);

  gnutls_free (pkcs7);
}

/**
 * gnutls_pkcs7_import:
 * @pkcs7: The structure to store the parsed PKCS7.
 * @data: The DER or PEM encoded PKCS7.
 * @format: One of DER or PEM
 *
 * This function will convert the given DER or PEM encoded PKCS7 to
 * the native #gnutls_pkcs7_t format.  The output will be stored in
 * @pkcs7.
 *
 * If the PKCS7 is PEM encoded it should have a header of "PKCS7".
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 **/
int
gnutls_pkcs7_import (gnutls_pkcs7_t pkcs7, const gnutls_datum_t * data,
                     gnutls_x509_crt_fmt_t format)
{
  int result = 0, need_free = 0;
  gnutls_datum_t _data;

  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

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

  /* If the PKCS7 is in PEM format then decode it
   */
  if (format == GNUTLS_X509_FMT_PEM)
    {
      uint8_t *out;

      result = _gnutls_fbase64_decode (PEM_PKCS7, data->data, data->size,
                                       &out);

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

      _data.data = out;
      _data.size = result;

      need_free = 1;
    }


  result = asn1_der_decoding (&pkcs7->pkcs7, _data.data, _data.size, NULL);
  if (result != ASN1_SUCCESS)
    {
      result = _gnutls_asn2err (result);
      gnutls_assert ();
      goto cleanup;
    }

  if (need_free)
    _gnutls_free_datum (&_data);

  return 0;

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

/**
 * gnutls_pkcs7_get_crt_raw:
 * @pkcs7: should contain a gnutls_pkcs7_t structure
 * @indx: contains the index of the certificate to extract
 * @certificate: the contents of the certificate will be copied
 *   there (may be null)
 * @certificate_size: should hold the size of the certificate
 *
 * This function will return a certificate of the PKCS7 or RFC2630
 * certificate set.
 *
 * After the last certificate has been read
 * %GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.  If the provided buffer is not long enough,
 *   then @certificate_size is updated and
 *   %GNUTLS_E_SHORT_MEMORY_BUFFER is returned.
 **/
int
gnutls_pkcs7_get_crt_raw (gnutls_pkcs7_t pkcs7,
                          int indx, void *certificate,
                          size_t * certificate_size)
{
  ASN1_TYPE c2 = ASN1_TYPE_EMPTY;
  int result, len;
  char root2[ASN1_MAX_NAME_SIZE];
  char oid[MAX_OID_SIZE];
  gnutls_datum_t tmp = { NULL, 0 };

  if (certificate_size == NULL || pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  /* Step 1. decode the signed data.
   */
  result = _decode_pkcs7_signed_data (pkcs7->pkcs7, &c2, &tmp);
  if (result < 0)
    {
      gnutls_assert ();
      return result;
    }

  /* Step 2. Parse the CertificateSet 
   */

  snprintf (root2, sizeof (root2), "certificates.?%u", indx + 1);

  len = sizeof (oid) - 1;

  result = asn1_read_value (c2, root2, oid, &len);

  if (result == ASN1_VALUE_NOT_FOUND)
    {
      result = GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
      goto cleanup;
    }

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

  /* if 'Certificate' is the choice found: 
   */
  if (strcmp (oid, "certificate") == 0)
    {
      int start, end;

      result = asn1_der_decoding_startEnd (c2, tmp.data, tmp.size,
                                           root2, &start, &end);

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

      end = end - start + 1;

      if ((unsigned) end > *certificate_size)
        {
          *certificate_size = end;
          result = GNUTLS_E_SHORT_MEMORY_BUFFER;
          goto cleanup;
        }

      if (certificate)
        memcpy (certificate, &tmp.data[start], end);

      *certificate_size = end;

      result = 0;

    }
  else
    {
      result = GNUTLS_E_UNSUPPORTED_CERTIFICATE_TYPE;
    }

cleanup:
  _gnutls_free_datum (&tmp);
  if (c2)
    asn1_delete_structure (&c2);
  return result;
}

/**
 * gnutls_pkcs7_get_crt_count:
 * @pkcs7: should contain a #gnutls_pkcs7_t structure
 *
 * This function will return the number of certifcates in the PKCS7
 * or RFC2630 certificate set.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 **/
int
gnutls_pkcs7_get_crt_count (gnutls_pkcs7_t pkcs7)
{
  ASN1_TYPE c2 = ASN1_TYPE_EMPTY;
  int result, count;

  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  /* Step 1. decode the signed data.
   */
  result = _decode_pkcs7_signed_data (pkcs7->pkcs7, &c2, NULL);
  if (result < 0)
    {
      gnutls_assert ();
      return result;
    }

  /* Step 2. Count the CertificateSet */

  result = asn1_number_of_elements (c2, "certificates", &count);

  asn1_delete_structure (&c2);

  if (result != ASN1_SUCCESS)
    {
      gnutls_assert ();
      return 0;                 /* no certificates */
    }

  return count;

}

/**
 * gnutls_pkcs7_export:
 * @pkcs7: Holds the pkcs7 structure
 * @format: the format of output params. One of PEM or DER.
 * @output_data: will contain a structure 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 pkcs7 structure to DER or PEM format.
 *
 * 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 PKCS7".
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
  **/
int
gnutls_pkcs7_export (gnutls_pkcs7_t pkcs7,
                     gnutls_x509_crt_fmt_t format, void *output_data,
                     size_t * output_data_size)
{
  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  return _gnutls_x509_export_int (pkcs7->pkcs7, format, PEM_PKCS7,
                                  output_data, output_data_size);
}

/* Creates an empty signed data structure in the pkcs7
 * structure and returns a handle to the signed data.
 */
static int
create_empty_signed_data (ASN1_TYPE pkcs7, ASN1_TYPE * sdata)
{
  uint8_t one = 1;
  int result;

  *sdata = ASN1_TYPE_EMPTY;

  if ((result = asn1_create_element
       (_gnutls_get_pkix (), "PKIX1.pkcs-7-SignedData",
        sdata)) != ASN1_SUCCESS)
    {
      gnutls_assert ();
      result = _gnutls_asn2err (result);
      goto cleanup;
    }

  /* Use version 1
   */
  result = asn1_write_value (*sdata, "version", &one, 1);
  if (result != ASN1_SUCCESS)
    {
      gnutls_assert ();
      result = _gnutls_asn2err (result);
      goto cleanup;
    }

  /* Use no digest algorithms
   */

  /* id-data */
  result =
    asn1_write_value (*sdata, "encapContentInfo.eContentType",
                      "1.2.840.113549.1.7.5", 1);
  if (result != ASN1_SUCCESS)
    {
      gnutls_assert ();
      result = _gnutls_asn2err (result);
      goto cleanup;
    }

  result = asn1_write_value (*sdata, "encapContentInfo.eContent", NULL, 0);
  if (result != ASN1_SUCCESS)
    {
      gnutls_assert ();
      result = _gnutls_asn2err (result);
      goto cleanup;
    }

  /* Add no certificates.
   */

  /* Add no crls.
   */

  /* Add no signerInfos.
   */

  /* Write the content type of the signed data
   */
  result = asn1_write_value (pkcs7, "contentType", SIGNED_DATA_OID, 1);
  if (result != ASN1_SUCCESS)
    {
      gnutls_assert ();
      result = _gnutls_asn2err (result);
      goto cleanup;
    }

  return 0;

cleanup:
  asn1_delete_structure (sdata);
  return result;

}

/**
 * gnutls_pkcs7_set_crt_raw:
 * @pkcs7: should contain a #gnutls_pkcs7_t structure
 * @crt: the DER encoded certificate to be added
 *
 * This function will add a certificate to the PKCS7 or RFC2630
 * certificate set.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 **/
int
gnutls_pkcs7_set_crt_raw (gnutls_pkcs7_t pkcs7, const gnutls_datum_t * crt)
{
  ASN1_TYPE c2 = ASN1_TYPE_EMPTY;
  int result;

  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  /* Step 1. decode the signed data.
   */
  result = _decode_pkcs7_signed_data (pkcs7->pkcs7, &c2, NULL);
  if (result < 0 && result != GNUTLS_E_ASN1_VALUE_NOT_FOUND)
    {
      gnutls_assert ();
      return result;
    }

  /* If the signed data are uninitialized
   * then create them.
   */
  if (result == GNUTLS_E_ASN1_VALUE_NOT_FOUND)
    {
      /* The pkcs7 structure is new, so create the
       * signedData.
       */
      result = create_empty_signed_data (pkcs7->pkcs7, &c2);
      if (result < 0)
        {
          gnutls_assert ();
          return result;
        }
    }

  /* Step 2. Append the new certificate.
   */

  result = asn1_write_value (c2, "certificates", "NEW", 1);
  if (result != ASN1_SUCCESS)
    {
      gnutls_assert ();
      result = _gnutls_asn2err (result);
      goto cleanup;
    }

  result = asn1_write_value (c2, "certificates.?LAST", "certificate", 1);
  if (result != ASN1_SUCCESS)
    {
      gnutls_assert ();
      result = _gnutls_asn2err (result);
      goto cleanup;
    }

  result =
    asn1_write_value (c2, "certificates.?LAST.certificate", crt->data,
                      crt->size);
  if (result != ASN1_SUCCESS)
    {
      gnutls_assert ();
      result = _gnutls_asn2err (result);
      goto cleanup;
    }

  /* Step 3. Replace the old content with the new
   */
  result =
    _gnutls_x509_der_encode_and_copy (c2, "", pkcs7->pkcs7, "content", 0);
  if (result < 0)
    {
      gnutls_assert ();
      goto cleanup;
    }

  asn1_delete_structure (&c2);

  return 0;

cleanup:
  if (c2)
    asn1_delete_structure (&c2);
  return result;
}

/**
 * gnutls_pkcs7_set_crt:
 * @pkcs7: should contain a #gnutls_pkcs7_t structure
 * @crt: the certificate to be copied.
 *
 * This function will add a parsed certificate to the PKCS7 or
 * RFC2630 certificate set.  This is a wrapper function over
 * gnutls_pkcs7_set_crt_raw() .
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 **/
int
gnutls_pkcs7_set_crt (gnutls_pkcs7_t pkcs7, gnutls_x509_crt_t crt)
{
  int ret;
  gnutls_datum_t data;

  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  ret = _gnutls_x509_der_encode (crt->cert, "", &data, 0);
  if (ret < 0)
    {
      gnutls_assert ();
      return ret;
    }

  ret = gnutls_pkcs7_set_crt_raw (pkcs7, &data);

  _gnutls_free_datum (&data);

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

  return 0;
}


/**
 * gnutls_pkcs7_delete_crt:
 * @pkcs7: should contain a gnutls_pkcs7_t structure
 * @indx: the index of the certificate to delete
 *
 * This function will delete a certificate from a PKCS7 or RFC2630
 * certificate set.  Index starts from 0. Returns 0 on success.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 **/
int
gnutls_pkcs7_delete_crt (gnutls_pkcs7_t pkcs7, int indx)
{
  ASN1_TYPE c2 = ASN1_TYPE_EMPTY;
  int result;
  char root2[ASN1_MAX_NAME_SIZE];

  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  /* Step 1. Decode the signed data.
   */
  result = _decode_pkcs7_signed_data (pkcs7->pkcs7, &c2, NULL);
  if (result < 0)
    {
      gnutls_assert ();
      return result;
    }

  /* Step 2. Delete the certificate.
   */

  snprintf (root2, sizeof (root2), "certificates.?%u", indx + 1);

  result = asn1_write_value (c2, root2, NULL, 0);
  if (result != ASN1_SUCCESS)
    {
      gnutls_assert ();
      result = _gnutls_asn2err (result);
      goto cleanup;
    }

  /* Step 3. Replace the old content with the new
   */
  result =
    _gnutls_x509_der_encode_and_copy (c2, "", pkcs7->pkcs7, "content", 0);
  if (result < 0)
    {
      gnutls_assert ();
      goto cleanup;
    }

  asn1_delete_structure (&c2);

  return 0;

cleanup:
  if (c2)
    asn1_delete_structure (&c2);
  return result;
}

/* Read and write CRLs
 */

/**
 * gnutls_pkcs7_get_crl_raw:
 * @pkcs7: should contain a #gnutls_pkcs7_t structure
 * @indx: contains the index of the crl to extract
 * @crl: the contents of the crl will be copied there (may be null)
 * @crl_size: should hold the size of the crl
 *
 * This function will return a crl of the PKCS7 or RFC2630 crl set.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.  If the provided buffer is not long enough,
 *   then @crl_size is updated and %GNUTLS_E_SHORT_MEMORY_BUFFER is
 *   returned.  After the last crl has been read
 *   %GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.
 **/
int
gnutls_pkcs7_get_crl_raw (gnutls_pkcs7_t pkcs7,
                          int indx, void *crl, size_t * crl_size)
{
  ASN1_TYPE c2 = ASN1_TYPE_EMPTY;
  int result;
  char root2[ASN1_MAX_NAME_SIZE];
  gnutls_datum_t tmp = { NULL, 0 };
  int start, end;

  if (pkcs7 == NULL || crl_size == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  /* Step 1. decode the signed data.
   */
  result = _decode_pkcs7_signed_data (pkcs7->pkcs7, &c2, &tmp);
  if (result < 0)
    {
      gnutls_assert ();
      return result;
    }

  /* Step 2. Parse the CertificateSet 
   */

  snprintf (root2, sizeof (root2), "crls.?%u", indx + 1);

  /* Get the raw CRL 
   */
  result = asn1_der_decoding_startEnd (c2, tmp.data, tmp.size,
                                       root2, &start, &end);

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

  end = end - start + 1;

  if ((unsigned) end > *crl_size)
    {
      *crl_size = end;
      result = GNUTLS_E_SHORT_MEMORY_BUFFER;
      goto cleanup;
    }

  if (crl)
    memcpy (crl, &tmp.data[start], end);

  *crl_size = end;

  result = 0;

cleanup:
  _gnutls_free_datum (&tmp);
  if (c2)
    asn1_delete_structure (&c2);
  return result;
}

/**
 * gnutls_pkcs7_get_crl_count:
 * @pkcs7: should contain a gnutls_pkcs7_t structure
 *
 * This function will return the number of certifcates in the PKCS7
 * or RFC2630 crl set.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 **/
int
gnutls_pkcs7_get_crl_count (gnutls_pkcs7_t pkcs7)
{
  ASN1_TYPE c2 = ASN1_TYPE_EMPTY;
  int result, count;

  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  /* Step 1. decode the signed data.
   */
  result = _decode_pkcs7_signed_data (pkcs7->pkcs7, &c2, NULL);
  if (result < 0)
    {
      gnutls_assert ();
      return result;
    }

  /* Step 2. Count the CertificateSet */

  result = asn1_number_of_elements (c2, "crls", &count);

  asn1_delete_structure (&c2);

  if (result != ASN1_SUCCESS)
    {
      gnutls_assert ();
      return 0;                 /* no crls */
    }

  return count;

}

/**
 * gnutls_pkcs7_set_crl_raw:
 * @pkcs7: should contain a #gnutls_pkcs7_t structure
 * @crl: the DER encoded crl to be added
 *
 * This function will add a crl to the PKCS7 or RFC2630 crl set.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 **/
int
gnutls_pkcs7_set_crl_raw (gnutls_pkcs7_t pkcs7, const gnutls_datum_t * crl)
{
  ASN1_TYPE c2 = ASN1_TYPE_EMPTY;
  int result;

  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  /* Step 1. decode the signed data.
   */
  result = _decode_pkcs7_signed_data (pkcs7->pkcs7, &c2, NULL);
  if (result < 0 && result != GNUTLS_E_ASN1_VALUE_NOT_FOUND)
    {
      gnutls_assert ();
      return result;
    }

  /* If the signed data are uninitialized
   * then create them.
   */
  if (result == GNUTLS_E_ASN1_VALUE_NOT_FOUND)
    {
      /* The pkcs7 structure is new, so create the
       * signedData.
       */
      result = create_empty_signed_data (pkcs7->pkcs7, &c2);
      if (result < 0)
        {
          gnutls_assert ();
          return result;
        }
    }

  /* Step 2. Append the new crl.
   */

  result = asn1_write_value (c2, "crls", "NEW", 1);
  if (result != ASN1_SUCCESS)
    {
      gnutls_assert ();
      result = _gnutls_asn2err (result);
      goto cleanup;
    }

  result = asn1_write_value (c2, "crls.?LAST", crl->data, crl->size);
  if (result != ASN1_SUCCESS)
    {
      gnutls_assert ();
      result = _gnutls_asn2err (result);
      goto cleanup;
    }

  /* Step 3. Replace the old content with the new
   */
  result =
    _gnutls_x509_der_encode_and_copy (c2, "", pkcs7->pkcs7, "content", 0);
  if (result < 0)
    {
      gnutls_assert ();
      goto cleanup;
    }

  asn1_delete_structure (&c2);

  return 0;

cleanup:
  if (c2)
    asn1_delete_structure (&c2);
  return result;
}

/**
 * gnutls_pkcs7_set_crl:
 * @pkcs7: should contain a #gnutls_pkcs7_t structure
 * @crl: the DER encoded crl to be added
 *
 * This function will add a parsed CRL to the PKCS7 or RFC2630 crl
 * set.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 **/
int
gnutls_pkcs7_set_crl (gnutls_pkcs7_t pkcs7, gnutls_x509_crl_t crl)
{
  int ret;
  gnutls_datum_t data;

  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  ret = _gnutls_x509_der_encode (crl->crl, "", &data, 0);
  if (ret < 0)
    {
      gnutls_assert ();
      return ret;
    }

  ret = gnutls_pkcs7_set_crl_raw (pkcs7, &data);

  _gnutls_free_datum (&data);

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

  return 0;
}

/**
 * gnutls_pkcs7_delete_crl:
 * @pkcs7: should contain a #gnutls_pkcs7_t structure
 * @indx: the index of the crl to delete
 *
 * This function will delete a crl from a PKCS7 or RFC2630 crl set.
 * Index starts from 0. Returns 0 on success.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 **/
int
gnutls_pkcs7_delete_crl (gnutls_pkcs7_t pkcs7, int indx)
{
  ASN1_TYPE c2 = ASN1_TYPE_EMPTY;
  int result;
  char root2[ASN1_MAX_NAME_SIZE];

  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  /* Step 1. Decode the signed data.
   */
  result = _decode_pkcs7_signed_data (pkcs7->pkcs7, &c2, NULL);
  if (result < 0)
    {
      gnutls_assert ();
      return result;
    }

  /* Step 2. Delete the crl.
   */

  snprintf (root2, sizeof (root2), "crls.?%u", indx + 1);

  result = asn1_write_value (c2, root2, NULL, 0);
  if (result != ASN1_SUCCESS)
    {
      gnutls_assert ();
      result = _gnutls_asn2err (result);
      goto cleanup;
    }

  /* Step 3. Replace the old content with the new
   */
  result =
    _gnutls_x509_der_encode_and_copy (c2, "", pkcs7->pkcs7, "content", 0);
  if (result < 0)
    {
      gnutls_assert ();
      goto cleanup;
    }

  asn1_delete_structure (&c2);

  return 0;

cleanup:
  if (c2)
    asn1_delete_structure (&c2);
  return result;
}

#endif /* ENABLE_PKI */