/src/gnutls/lib/x509/pkcs7.c

Source
/*
 * Copyright (C) 2003-2015 Free Software Foundation, Inc.
 * Copyright (C) 2015 Red Hat, 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 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/>
 *
 */

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

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

#include "datum.h"
#include "global.h"
#include "errors.h"
#include "common.h"
#include "x509_b64.h"
#include "pkcs7_int.h"
#include <gnutls/abstract.h>
#include <gnutls/pkcs7.h>

#define ATTR_MESSAGE_DIGEST "1.2.840.113549.1.9.4"
#define ATTR_SIGNING_TIME "1.2.840.113549.1.9.5"
#define ATTR_CONTENT_TYPE "1.2.840.113549.1.9.3"

static const uint8_t one = 1;

/* Decodes the PKCS #7 signed data, and returns an asn1_node,
 * 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(gnutls_pkcs7_t pkcs7)
{
  asn1_node c2;
  int len, result;
  gnutls_datum_t tmp = { NULL, 0 };

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

  if (!streq(pkcs7->encap_data_oid, SIGNED_DATA_OID)) {
    gnutls_assert();
    _gnutls_debug_log("Unknown PKCS7 Content OID '%s'\n",
          pkcs7->encap_data_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.
   */
  result = _gnutls_x509_read_value(pkcs7->pkcs7, "content", &tmp);
  if (result < 0) {
    gnutls_assert();
    goto cleanup;
  }

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

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

  /* read the encapsulated content */
  len = MAX_OID_SIZE - 1;
  result = asn1_read_value(c2, "encapContentInfo.eContentType",
         pkcs7->encap_data_oid, &len);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto cleanup;
  }

  if (!streq(pkcs7->encap_data_oid, DATA_OID) &&
      !streq(pkcs7->encap_data_oid, DIGESTED_DATA_OID)) {
    _gnutls_debug_log(
      "Unknown PKCS#7 Encapsulated Content OID '%s'; treating as raw data\n",
      pkcs7->encap_data_oid);
  }

  /* Try reading as octet string according to rfc5652. If that fails, attempt
   * a raw read according to rfc2315 */
  result = _gnutls_x509_read_string(c2, "encapContentInfo.eContent",
            &pkcs7->der_signed_data,
            ASN1_ETYPE_OCTET_STRING, 1);
  if (result < 0) {
    result = _gnutls_x509_read_value(c2,
             "encapContentInfo.eContent",
             &pkcs7->der_signed_data);
    if (result < 0) {
      pkcs7->der_signed_data.data = NULL;
      pkcs7->der_signed_data.size = 0;
    } else {
      int tag_len, len_len;
      unsigned char cls;
      unsigned long tag;

      /* we skip the embedded element's tag and length - uncharted territorry - used by MICROSOFT_CERT_TRUST_LIST */
      result = asn1_get_tag_der(pkcs7->der_signed_data.data,
              pkcs7->der_signed_data.size,
              &cls, &tag_len, &tag);
      if (result != ASN1_SUCCESS) {
        gnutls_assert();
        result = _gnutls_asn2err(result);
        goto cleanup;
      }

      result = asn1_get_length_ber(
        pkcs7->der_signed_data.data + tag_len,
        pkcs7->der_signed_data.size - tag_len,
        &len_len);
      if (result < 0) {
        gnutls_assert();
        result = GNUTLS_E_ASN1_DER_ERROR;
        goto cleanup;
      }

      tag_len += len_len;
      memmove(pkcs7->der_signed_data.data,
        &pkcs7->der_signed_data.data[tag_len],
        pkcs7->der_signed_data.size - tag_len);
      pkcs7->der_signed_data.size -= tag_len;
    }
  }

  if (pkcs7->signed_data)
    asn1_delete_structure(&pkcs7->signed_data);
  pkcs7->signed_data = c2;
  gnutls_free(tmp.data);

  return 0;

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

static int pkcs7_reinit(gnutls_pkcs7_t pkcs7)
{
  int result;

  asn1_delete_structure(&pkcs7->pkcs7);

  result = asn1_create_element(_gnutls_get_pkix(),
             "PKIX1.pkcs-7-ContentInfo", &pkcs7->pkcs7);
  if (result != ASN1_SUCCESS) {
    result = _gnutls_asn2err(result);
    gnutls_assert();
    return result;
  }

  return 0;
}

/**
 * gnutls_pkcs7_init:
 * @pkcs7: A pointer to the type 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 = pkcs7_reinit(*pkcs7);
    if (result < 0) {
      gnutls_assert();
      gnutls_free(*pkcs7);
      return result;
    }
    return 0; /* success */
  }
  return GNUTLS_E_MEMORY_ERROR;
}

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

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

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

  _gnutls_free_datum(&pkcs7->der_signed_data);

  gnutls_free(pkcs7);
}

/**
 * gnutls_pkcs7_import:
 * @pkcs7: The data 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. Any signed data that may be present inside the @pkcs7
 * structure, like certificates set by gnutls_pkcs7_set_crt(), will
 * be freed and overwritten by this function.
 *
 * 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) {
    result = _gnutls_fbase64_decode(PEM_PKCS7, data->data,
            data->size, &_data);

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

    need_free = 1;
  }

  if (pkcs7->expanded) {
    result = pkcs7_reinit(pkcs7);
    if (result < 0) {
      gnutls_assert();
      goto cleanup;
    }
  }
  pkcs7->expanded = 1;

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

  /* Decode the signed data.
   */
  result = _decode_pkcs7_signed_data(pkcs7);
  if (result < 0) {
    gnutls_assert();
    goto cleanup;
  }

  result = 0;

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

/**
 * gnutls_pkcs7_get_crt_raw2:
 * @pkcs7: should contain a gnutls_pkcs7_t type
 * @indx: contains the index of the certificate to extract
 * @cert: will hold the contents of the certificate; must be deallocated with gnutls_free()
 *
 * 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.
 *
 * Since: 3.4.2
 **/
int gnutls_pkcs7_get_crt_raw2(gnutls_pkcs7_t pkcs7, unsigned indx,
            gnutls_datum_t *cert)
{
  int result, len;
  char root2[MAX_NAME_SIZE];
  char oid[MAX_OID_SIZE];
  gnutls_datum_t tmp = { NULL, 0 };

  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  /* Step 2. Parse the CertificateSet
   */
  snprintf(root2, sizeof(root2), "certificates.?%u", indx + 1);

  len = sizeof(oid) - 1;

  result = asn1_read_value(pkcs7->signed_data, 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 (streq(oid, "certificate")) {
    int start, end;

    result = _gnutls_x509_read_value(pkcs7->pkcs7, "content", &tmp);
    if (result < 0) {
      gnutls_assert();
      goto cleanup;
    }

    result = asn1_der_decoding_startEnd(pkcs7->signed_data,
                tmp.data, tmp.size, root2,
                &start, &end);

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

    end = end - start + 1;

    result = _gnutls_set_datum(cert, &tmp.data[start], end);
  } else {
    result = GNUTLS_E_UNSUPPORTED_CERTIFICATE_TYPE;
  }

cleanup:
  _gnutls_free_datum(&tmp);
  return result;
}

/**
 * gnutls_pkcs7_get_crt_raw:
 * @pkcs7: should contain a gnutls_pkcs7_t type
 * @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, unsigned indx,
           void *certificate, size_t *certificate_size)
{
  int ret;
  gnutls_datum_t tmp = { NULL, 0 };

  ret = gnutls_pkcs7_get_crt_raw2(pkcs7, indx, &tmp);
  if (ret < 0)
    return gnutls_assert_val(ret);

  if ((unsigned)tmp.size > *certificate_size) {
    *certificate_size = tmp.size;
    ret = GNUTLS_E_SHORT_MEMORY_BUFFER;
    goto cleanup;
  }

  *certificate_size = tmp.size;
  if (certificate)
    memcpy(certificate, tmp.data, tmp.size);

cleanup:
  _gnutls_free_datum(&tmp);
  return ret;
}

/**
 * gnutls_pkcs7_get_crt_count:
 * @pkcs7: should contain a #gnutls_pkcs7_t type
 *
 * This function will return the number of certificates in the PKCS7
 * or RFC2630 certificate set.
 *
 * Returns: On success, a positive number is returned, otherwise a
 *   negative error value.
 **/
int gnutls_pkcs7_get_crt_count(gnutls_pkcs7_t pkcs7)
{
  int result, count;

  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  /* Step 2. Count the CertificateSet */

  result = asn1_number_of_elements(pkcs7->signed_data, "certificates",
           &count);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    return 0; /* no certificates */
  }

  return count;
}

/**
 * gnutls_pkcs7_signature_info_deinit:
 * @info: should point to a #gnutls_pkcs7_signature_info_st structure
 *
 * This function will deinitialize any allocated value in the
 * provided #gnutls_pkcs7_signature_info_st.
 *
 * Since: 3.4.2
 **/
void gnutls_pkcs7_signature_info_deinit(gnutls_pkcs7_signature_info_st *info)
{
  gnutls_free(info->sig.data);
  gnutls_free(info->issuer_dn.data);
  gnutls_free(info->signer_serial.data);
  gnutls_free(info->issuer_keyid.data);
  gnutls_pkcs7_attrs_deinit(info->signed_attrs);
  gnutls_pkcs7_attrs_deinit(info->unsigned_attrs);
  memset(info, 0, sizeof(*info));
}

static time_t parse_time(gnutls_pkcs7_t pkcs7, const char *root)
{
  char tval[128];
  asn1_node c2 = NULL;
  time_t ret;
  int result, len;

  result = asn1_create_element(_gnutls_get_pkix(), "PKIX1.Time", &c2);
  if (result != ASN1_SUCCESS) {
    ret = -1;
    gnutls_assert();
    goto cleanup;
  }

  len = sizeof(tval);
  result = asn1_read_value(pkcs7->signed_data, root, tval, &len);
  if (result != ASN1_SUCCESS) {
    ret = -1;
    gnutls_assert();
    goto cleanup;
  }

  result = _asn1_strict_der_decode(&c2, tval, len, NULL);
  if (result != ASN1_SUCCESS) {
    ret = -1;
    gnutls_assert();
    goto cleanup;
  }

  ret = _gnutls_x509_get_time(c2, "", 0);

cleanup:
  asn1_delete_structure(&c2);
  return ret;
}

/**
 * gnutls_pkcs7_get_signature_count:
 * @pkcs7: should contain a #gnutls_pkcs7_t type
 *
 * This function will return the number of signatures in the PKCS7
 * structure.
 *
 * Returns: On success, a positive number is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.4.3
 **/
int gnutls_pkcs7_get_signature_count(gnutls_pkcs7_t pkcs7)
{
  int ret, count;

  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  ret = asn1_number_of_elements(pkcs7->signed_data, "signerInfos",
              &count);
  if (ret != ASN1_SUCCESS) {
    gnutls_assert();
    return 0;
  }

  return count;
}

/**
 * gnutls_pkcs7_get_signature_info:
 * @pkcs7: should contain a #gnutls_pkcs7_t type
 * @idx: the index of the signature info to check
 * @info: will contain the output signature
 *
 * This function will return information about the signature identified
 * by idx in the provided PKCS #7 structure. The information should be
 * deinitialized using gnutls_pkcs7_signature_info_deinit().
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.4.2
 **/
int gnutls_pkcs7_get_signature_info(gnutls_pkcs7_t pkcs7, unsigned idx,
            gnutls_pkcs7_signature_info_st *info)
{
  int ret, count, len;
  char root[256];
  char oid[MAX_OID_SIZE];
  gnutls_pk_algorithm_t pk;
  gnutls_sign_algorithm_t sig;
  gnutls_datum_t tmp = { NULL, 0 };
  unsigned i;

  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  memset(info, 0, sizeof(*info));
  info->signing_time = -1;

  ret = asn1_number_of_elements(pkcs7->signed_data, "signerInfos",
              &count);
  if (ret != ASN1_SUCCESS || idx + 1 > (unsigned)count) {
    gnutls_assert();
    return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
  }
  snprintf(root, sizeof(root),
     "signerInfos.?%u.signatureAlgorithm.algorithm", idx + 1);

  len = sizeof(oid) - 1;
  ret = asn1_read_value(pkcs7->signed_data, root, oid, &len);
  if (ret != ASN1_SUCCESS) {
    gnutls_assert();
    goto unsupp_algo;
  }

  sig = gnutls_oid_to_sign(oid);
  if (sig == GNUTLS_SIGN_UNKNOWN) {
    /* great PKCS #7 allows to only specify a public key algo */
    pk = gnutls_oid_to_pk(oid);
    if (pk == GNUTLS_PK_UNKNOWN) {
      gnutls_assert();
      goto unsupp_algo;
    }

    /* use the digests algorithm */
    snprintf(root, sizeof(root),
       "signerInfos.?%u.digestAlgorithm.algorithm", idx + 1);

    len = sizeof(oid) - 1;
    ret = asn1_read_value(pkcs7->signed_data, root, oid, &len);
    if (ret != ASN1_SUCCESS) {
      gnutls_assert();
      goto unsupp_algo;
    }

    ret = gnutls_oid_to_digest(oid);
    if (ret == GNUTLS_DIG_UNKNOWN) {
      gnutls_assert();
      goto unsupp_algo;
    }

    sig = gnutls_pk_to_sign(pk, ret);
    if (sig == GNUTLS_SIGN_UNKNOWN) {
      gnutls_assert();
      goto unsupp_algo;
    }
  }

  info->algo = sig;

  snprintf(root, sizeof(root), "signerInfos.?%u.signature", idx + 1);
  /* read the signature */
  ret = _gnutls_x509_read_value(pkcs7->signed_data, root, &info->sig);
  if (ret < 0) {
    gnutls_assert();
    goto fail;
  }

  /* read the issuer info */
  snprintf(root, sizeof(root),
     "signerInfos.?%u.sid.issuerAndSerialNumber.issuer.rdnSequence",
     idx + 1);
  /* read the signature */
  ret = _gnutls_x509_get_raw_field(pkcs7->signed_data, root,
           &info->issuer_dn);
  if (ret >= 0) {
    snprintf(
      root, sizeof(root),
      "signerInfos.?%u.sid.issuerAndSerialNumber.serialNumber",
      idx + 1);
    /* read the signature */
    ret = _gnutls_x509_read_value(pkcs7->signed_data, root,
                &info->signer_serial);
    if (ret < 0) {
      gnutls_assert();
      goto fail;
    }
  } else { /* keyid */
    snprintf(root, sizeof(root),
       "signerInfos.?%u.sid.subjectKeyIdentifier", idx + 1);
    /* read the signature */
    ret = _gnutls_x509_read_value(pkcs7->signed_data, root,
                &info->issuer_keyid);
    if (ret < 0) {
      gnutls_assert();
    }
  }

  if (info->issuer_keyid.data == NULL && info->issuer_dn.data == NULL) {
    ret = gnutls_assert_val(GNUTLS_E_PARSING_ERROR);
    goto fail;
  }

  /* read the signing time */
  for (i = 0;; i++) {
    snprintf(root, sizeof(root),
       "signerInfos.?%u.signedAttrs.?%u.type", idx + 1,
       i + 1);
    len = sizeof(oid) - 1;
    ret = asn1_read_value(pkcs7->signed_data, root, oid, &len);
    if (ret != ASN1_SUCCESS) {
      break;
    }

    snprintf(root, sizeof(root),
       "signerInfos.?%u.signedAttrs.?%u.values.?1", idx + 1,
       i + 1);
    ret = _gnutls_x509_read_value(pkcs7->signed_data, root, &tmp);
    if (ret == GNUTLS_E_ASN1_ELEMENT_NOT_FOUND) {
      tmp.data = NULL;
      tmp.size = 0;
    } else if (ret < 0) {
      gnutls_assert();
      goto fail;
    }

    ret = gnutls_pkcs7_add_attr(&info->signed_attrs, oid, &tmp, 0);
    gnutls_free(tmp.data);

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

    if (streq(oid, ATTR_SIGNING_TIME)) {
      info->signing_time = parse_time(pkcs7, root);
    }
  }

  /* read the unsigned attrs */
  for (i = 0;; i++) {
    snprintf(root, sizeof(root),
       "signerInfos.?%u.unsignedAttrs.?%u.type", idx + 1,
       i + 1);
    len = sizeof(oid) - 1;
    ret = asn1_read_value(pkcs7->signed_data, root, oid, &len);
    if (ret != ASN1_SUCCESS) {
      break;
    }

    snprintf(root, sizeof(root),
       "signerInfos.?%u.unsignedAttrs.?%u.values.?1", idx + 1,
       i + 1);
    ret = _gnutls_x509_read_value(pkcs7->signed_data, root, &tmp);
    if (ret == GNUTLS_E_ASN1_ELEMENT_NOT_FOUND) {
      tmp.data = NULL;
      tmp.size = 0;
    } else if (ret < 0) {
      gnutls_assert();
      goto fail;
    }

    ret = gnutls_pkcs7_add_attr(&info->unsigned_attrs, oid, &tmp,
              0);
    gnutls_free(tmp.data);

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

  return 0;
fail:
  gnutls_free(tmp.data);
  gnutls_pkcs7_signature_info_deinit(info);
  return ret;
unsupp_algo:
  return GNUTLS_E_UNKNOWN_ALGORITHM;
}

/* Verifies that the hash attribute ATTR_MESSAGE_DIGEST is present
 * and matches our calculated hash */
static int verify_hash_attr(gnutls_pkcs7_t pkcs7, const char *root,
          gnutls_sign_algorithm_t algo,
          const gnutls_datum_t *data)
{
  unsigned hash;
  gnutls_datum_t tmp = { NULL, 0 };
  gnutls_datum_t tmp2 = { NULL, 0 };
  uint8_t hash_output[MAX_HASH_SIZE];
  unsigned hash_size, i;
  char oid[MAX_OID_SIZE];
  char name[256];
  unsigned msg_digest_ok = 0;
  unsigned num_cont_types = 0;
  int ret;

  hash = gnutls_sign_get_hash_algorithm(algo);

  /* hash the data */
  if (hash == GNUTLS_DIG_UNKNOWN)
    return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);

  hash_size = gnutls_hash_get_len(hash);

  if (data == NULL || data->data == NULL) {
    data = &pkcs7->der_signed_data;
  }

  if (data->size == 0) {
    return gnutls_assert_val(GNUTLS_E_NO_EMBEDDED_DATA);
  }

  ret = gnutls_hash_fast(hash, data->data, data->size, hash_output);
  if (ret < 0)
    return gnutls_assert_val(ret);

  /* now verify that hash matches */
  for (i = 0;; i++) {
    snprintf(name, sizeof(name), "%s.signedAttrs.?%u", root, i + 1);

    ret = _gnutls_x509_decode_and_read_attribute(
      pkcs7->signed_data, name, oid, sizeof(oid), &tmp, 1, 0);
    if (ret < 0) {
      if (ret == GNUTLS_E_ASN1_ELEMENT_NOT_FOUND)
        break;
      return gnutls_assert_val(ret);
    }

    if (streq(oid, ATTR_MESSAGE_DIGEST)) {
      ret = _gnutls_x509_decode_string(
        ASN1_ETYPE_OCTET_STRING, tmp.data, tmp.size,
        &tmp2, 0);
      if (ret < 0) {
        gnutls_assert();
        goto cleanup;
      }

      if (tmp2.size == hash_size &&
          memeq(hash_output, tmp2.data, tmp2.size)) {
        msg_digest_ok = 1;
      } else {
        gnutls_assert();
      }
    } else if (streq(oid, ATTR_CONTENT_TYPE)) {
      if (num_cont_types > 0) {
        gnutls_assert();
        ret = GNUTLS_E_PARSING_ERROR;
        goto cleanup;
      }

      num_cont_types++;

      /* check if it matches */
      ret = _gnutls_x509_get_raw_field(
        pkcs7->signed_data,
        "encapContentInfo.eContentType", &tmp2);
      if (ret < 0) {
        gnutls_assert();
        goto cleanup;
      }

      if (tmp2.size != tmp.size ||
          !memeq(tmp.data, tmp2.data, tmp2.size)) {
        gnutls_assert();
        ret = GNUTLS_E_PARSING_ERROR;
        goto cleanup;
      }
    }

    gnutls_free(tmp.data);
    gnutls_free(tmp2.data);
  }

  if (msg_digest_ok)
    ret = 0;
  else
    ret = gnutls_assert_val(GNUTLS_E_PK_SIG_VERIFY_FAILED);

cleanup:
  gnutls_free(tmp.data);
  gnutls_free(tmp2.data);
  return ret;
}

/* Returns the data to be used for signature verification. PKCS #7
 * decided that this should not be an easy task.
 */
static int figure_pkcs7_sigdata(gnutls_pkcs7_t pkcs7, const char *root,
        const gnutls_datum_t *data,
        gnutls_sign_algorithm_t algo,
        gnutls_datum_t *sigdata)
{
  int ret;
  char name[256];

  snprintf(name, sizeof(name), "%s.signedAttrs", root);
  /* read the signature */
  ret = _gnutls_x509_get_raw_field(pkcs7->signed_data, name, sigdata);
  if (ret == 0) {
    /* verify that hash matches */
    ret = verify_hash_attr(pkcs7, root, algo, data);
    if (ret < 0)
      return gnutls_assert_val(ret);

    if (sigdata->size > 0)
      sigdata->data[0] = 0x31;

    return 0;
  }

  /* We have no signedAttrs. Use the provided data, or the encapsulated */
  if (data == NULL || data->data == NULL) {
    return _gnutls_set_datum(sigdata, pkcs7->der_signed_data.data,
           pkcs7->der_signed_data.size);
  }

  return _gnutls_set_datum(sigdata, data->data, data->size);
}

/**
 * gnutls_pkcs7_get_embedded_data:
 * @pkcs7: should contain a gnutls_pkcs7_t type
 * @flags: must be zero or %GNUTLS_PKCS7_EDATA_GET_RAW
 * @data: will hold the embedded data in the provided structure
 *
 * This function will return the data embedded in the signature of
 * the PKCS7 structure. If no data are available then
 * %GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.
 *
 * The returned data must be de-allocated using gnutls_free().
 *
 * Note, that this function returns the exact same data that are
 * authenticated. If the %GNUTLS_PKCS7_EDATA_GET_RAW flag is provided,
 * the returned data will be including the wrapping tag/value as
 * they are encoded in the structure.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.4.8
 **/
int gnutls_pkcs7_get_embedded_data(gnutls_pkcs7_t pkcs7, unsigned flags,
           gnutls_datum_t *data)
{
  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  if (pkcs7->der_signed_data.size == 0)
    return gnutls_assert_val(GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE);

  if (flags & GNUTLS_PKCS7_EDATA_GET_RAW) {
    if (pkcs7->signed_data == NULL)
      return gnutls_assert_val(
        GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE);

    return _gnutls_x509_read_value(
      pkcs7->signed_data, "encapContentInfo.eContent", data);
  } else {
    return _gnutls_set_datum(data, pkcs7->der_signed_data.data,
           pkcs7->der_signed_data.size);
  }
}

/**
 * gnutls_pkcs7_get_embedded_data_oid:
 * @pkcs7: should contain a gnutls_pkcs7_t type
 *
 * This function will return the OID of the data embedded in the signature of
 * the PKCS7 structure. If no data are available then %NULL will be
 * returned. The returned value will be valid during the lifetime
 * of the @pkcs7 structure.
 *
 * Returns: On success, a pointer to an OID string, %NULL on error.
 *
 * Since: 3.5.5
 **/
const char *gnutls_pkcs7_get_embedded_data_oid(gnutls_pkcs7_t pkcs7)
{
  if (pkcs7 == NULL || pkcs7->encap_data_oid[0] == 0)
    return NULL;

  return pkcs7->encap_data_oid;
}

/**
 * gnutls_pkcs7_verify_direct:
 * @pkcs7: should contain a #gnutls_pkcs7_t type
 * @signer: the certificate believed to have signed the structure
 * @idx: the index of the signature info to check
 * @data: The data to be verified or %NULL
 * @flags: Zero or an OR list of #gnutls_certificate_verify_flags
 *
 * This function will verify the provided data against the signature
 * present in the SignedData of the PKCS #7 structure. If the data
 * provided are NULL then the data in the encapsulatedContent field
 * will be used instead.
 *
 * Note that, unlike gnutls_pkcs7_verify() this function does not
 * verify the key purpose of the signer. It is expected for the caller
 * to verify the intended purpose of the %signer -e.g., via gnutls_x509_crt_get_key_purpose_oid(),
 * or gnutls_x509_crt_check_key_purpose().
 *
 * Note also, that since GnuTLS 3.5.6 this function introduces checks in the
 * end certificate (@signer), including time checks and key usage checks.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value. A verification error results to a
 *   %GNUTLS_E_PK_SIG_VERIFY_FAILED and the lack of encapsulated data
 *   to verify to a %GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE.
 *
 * Since: 3.4.2
 **/
int gnutls_pkcs7_verify_direct(gnutls_pkcs7_t pkcs7, gnutls_x509_crt_t signer,
             unsigned idx, const gnutls_datum_t *data,
             unsigned flags)
{
  int count, ret;
  gnutls_datum_t tmpdata = { NULL, 0 };
  gnutls_pkcs7_signature_info_st info;
  gnutls_datum_t sigdata = { NULL, 0 };
  char root[128];

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

  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  ret = asn1_number_of_elements(pkcs7->signed_data, "signerInfos",
              &count);
  if (ret != ASN1_SUCCESS || idx + 1 > (unsigned)count) {
    gnutls_assert();
    return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
  }

  ret = gnutls_pkcs7_get_signature_info(pkcs7, idx, &info);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  snprintf(root, sizeof(root), "signerInfos.?%u", idx + 1);
  ret = figure_pkcs7_sigdata(pkcs7, root, data, info.algo, &sigdata);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  ret = gnutls_x509_crt_verify_data2(signer, info.algo, flags, &sigdata,
             &info.sig);
  if (ret < 0) {
    gnutls_assert();
  }

cleanup:
  gnutls_free(tmpdata.data);
  gnutls_free(sigdata.data);
  gnutls_pkcs7_signature_info_deinit(&info);

  return ret;
}

/* Finds the issuer of the given certificate (@cert) in the
 * included in PKCS#7 list of certificates */
static gnutls_x509_crt_t find_verified_issuer_of(gnutls_pkcs7_t pkcs7,
             gnutls_x509_crt_t cert,
             const char *purpose,
             unsigned vflags)
{
  gnutls_x509_crt_t issuer = NULL;
  int ret, count;
  gnutls_datum_t tmp = { NULL, 0 };
  unsigned i, vtmp;

  count = gnutls_pkcs7_get_crt_count(pkcs7);
  if (count < 0) {
    gnutls_assert();
    return NULL;
  }

  for (i = 0; i < (unsigned)count; i++) {
    /* Try to find the signer in the appended list. */
    ret = gnutls_pkcs7_get_crt_raw2(pkcs7, i, &tmp);
    if (ret < 0) {
      gnutls_assert();
      goto fail;
    }

    ret = gnutls_x509_crt_init(&issuer);
    if (ret < 0) {
      gnutls_assert();
      goto fail;
    }

    ret = gnutls_x509_crt_import(issuer, &tmp, GNUTLS_X509_FMT_DER);
    if (ret < 0) {
      gnutls_assert();
      goto fail;
    }

    if (!gnutls_x509_crt_check_issuer(cert, issuer)) {
      gnutls_assert();
      goto skip;
    }

    ret = gnutls_x509_crt_verify(
      cert, &issuer, 1,
      vflags | GNUTLS_VERIFY_DO_NOT_ALLOW_SAME, &vtmp);
    if (ret < 0 || vtmp != 0 ||
        (purpose != NULL &&
         !_gnutls_check_key_purpose(issuer, purpose, 0))) {
      gnutls_assert(); /* maybe next one is trusted */
      _gnutls_cert_log("failed verification with", issuer);
    skip:
      gnutls_x509_crt_deinit(issuer);
      issuer = NULL;
      gnutls_free(tmp.data);
      continue;
    }

    _gnutls_cert_log("issued by", issuer);

    /* we found a signer we trust. let's return it */
    break;
  }

  if (issuer == NULL) {
    gnutls_assert();
    return NULL;
  }
  goto cleanup;

fail:
  if (issuer) {
    gnutls_x509_crt_deinit(issuer);
    issuer = NULL;
  }

cleanup:
  gnutls_free(tmp.data);

  return issuer;
}

/* Finds a certificate that is issued by @issuer -if given-, and matches
 * either the serial number or the key ID (both in @info) .
 */
static gnutls_x509_crt_t
find_child_of_with_serial(gnutls_pkcs7_t pkcs7, gnutls_x509_crt_t issuer,
        const char *purpose,
        gnutls_pkcs7_signature_info_st *info)
{
  gnutls_x509_crt_t crt = NULL;
  int ret, count;
  uint8_t tmp[128];
  size_t tmp_size;
  gnutls_datum_t tmpdata = { NULL, 0 };
  unsigned i;

  count = gnutls_pkcs7_get_crt_count(pkcs7);
  if (count < 0) {
    gnutls_assert();
    return NULL;
  }

  for (i = 0; i < (unsigned)count; i++) {
    /* Try to find the crt in the appended list. */
    ret = gnutls_pkcs7_get_crt_raw2(pkcs7, i, &tmpdata);
    if (ret < 0) {
      gnutls_assert();
      goto fail;
    }

    ret = gnutls_x509_crt_init(&crt);
    if (ret < 0) {
      gnutls_assert();
      goto fail;
    }

    ret = gnutls_x509_crt_import(crt, &tmpdata,
               GNUTLS_X509_FMT_DER);
    if (ret < 0) {
      gnutls_assert();
      goto fail;
    }

    if (issuer != NULL) {
      if (!gnutls_x509_crt_check_issuer(crt, issuer)) {
        gnutls_assert();
        goto skip;
      }
    }

    if (purpose) {
      ret = _gnutls_check_key_purpose(crt, purpose, 0);
      if (ret == 0) {
        _gnutls_cert_log("key purpose unacceptable",
             crt);
        goto skip;
      }
    }

    if (info->signer_serial.size > 0) {
      tmp_size = sizeof(tmp);
      ret = gnutls_x509_crt_get_serial(crt, tmp, &tmp_size);
      if (ret < 0) {
        gnutls_assert();
        goto skip;
      }

      if (tmp_size != info->signer_serial.size ||
          !memeq(info->signer_serial.data, tmp, tmp_size)) {
        _gnutls_cert_log("doesn't match serial", crt);
        gnutls_assert();
        goto skip;
      }
    } else if (info->issuer_keyid.size > 0) {
      tmp_size = sizeof(tmp);
      ret = gnutls_x509_crt_get_subject_key_id(
        crt, tmp, &tmp_size, NULL);
      if (ret < 0) {
        gnutls_assert();
        goto skip;
      }

      if (tmp_size != info->issuer_keyid.size ||
          !memeq(info->issuer_keyid.data, tmp, tmp_size)) {
        _gnutls_cert_log("doesn't match key ID", crt);
        gnutls_assert();
      skip:
        gnutls_x509_crt_deinit(crt);
        crt = NULL;
        gnutls_free(tmpdata.data);
        continue;
      }
    } else {
      gnutls_assert();
      crt = NULL;
      goto fail;
    }

    _gnutls_cert_log("signer is", crt);

    /* we found the child with the given serial or key ID */
    break;
  }

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

  goto cleanup;
fail:
  if (crt) {
    gnutls_x509_crt_deinit(crt);
    crt = NULL;
  }

cleanup:
  gnutls_free(tmpdata.data);

  return crt;
}

static gnutls_x509_crt_t find_signer(gnutls_pkcs7_t pkcs7,
             gnutls_x509_trust_list_t tl,
             gnutls_typed_vdata_st *vdata,
             unsigned vdata_size, unsigned vflags,
             gnutls_pkcs7_signature_info_st *info)
{
  gnutls_x509_crt_t issuer = NULL;
  gnutls_x509_crt_t signer = NULL;
  int ret;
  gnutls_datum_t tmp = { NULL, 0 };
  unsigned i, vtmp;
  const char *purpose = NULL;

  if (info->issuer_keyid.data) {
    ret = gnutls_x509_trust_list_get_issuer_by_subject_key_id(
      tl, NULL, &info->issuer_keyid, &signer, 0);
    if (ret < 0) {
      gnutls_assert();
      signer = NULL;
    }
  }

  /* get key purpose */
  for (i = 0; i < vdata_size; i++) {
    if (vdata[i].type == GNUTLS_DT_KEY_PURPOSE_OID) {
      purpose = (char *)vdata[i].data;
      break;
    }
  }

  /* this will give us the issuer of the signer (wtf) */
  if (info->issuer_dn.data && signer == NULL) {
    ret = gnutls_x509_trust_list_get_issuer_by_dn(
      tl, &info->issuer_dn, &issuer, 0);
    if (ret < 0) {
      gnutls_assert();
      signer = NULL;
    }

    if (issuer) {
      /* try to find the actual signer in the list of
       * certificates */
      signer = find_child_of_with_serial(pkcs7, issuer,
                 purpose, info);
      if (signer == NULL) {
        gnutls_assert();
        goto fail;
      }

      gnutls_x509_crt_deinit(issuer);
      issuer = NULL;
    }
  }

  if (signer == NULL) {
    /* get the signer from the pkcs7 list; the one that matches serial
     * or key ID */
    signer = find_child_of_with_serial(pkcs7, NULL, purpose, info);
    if (signer == NULL) {
      gnutls_assert();
      goto fail;
    }

    /* if the signer cannot be verified from our trust list, make a chain of certificates
     * starting from the identified signer, to a root we know. */
    ret = gnutls_x509_trust_list_verify_crt2(
      tl, &signer, 1, vdata, vdata_size, vflags, &vtmp, NULL);
    if (ret < 0 || vtmp != 0) {
      gnutls_x509_crt_t prev = NULL;

      issuer = signer;
      /* construct a chain */
      do {
        if (prev && prev != signer) {
          gnutls_x509_crt_deinit(prev);
        }
        prev = issuer;

        issuer = find_verified_issuer_of(
          pkcs7, issuer, purpose, vflags);

        if (issuer != NULL &&
            gnutls_x509_crt_check_issuer(issuer,
                 issuer)) {
          if (prev && prev != signer)
            gnutls_x509_crt_deinit(prev);
          prev = issuer;
          break;
        }
      } while (issuer != NULL);

      issuer = prev; /* the last we have seen */

      if (issuer == NULL) {
        gnutls_assert();
        goto fail;
      }

      ret = gnutls_x509_trust_list_verify_crt2(
        tl, &issuer, 1, vdata, vdata_size, vflags,
        &vtmp, NULL);
      if (ret < 0 || vtmp != 0) {
        /* could not construct a valid chain */
        _gnutls_reason_log(
          "signer's chain failed trust list verification",
          vtmp);
        gnutls_assert();
        goto fail;
      }
    }
  } else {
    /* verify that the signer we got is trusted */
    ret = gnutls_x509_trust_list_verify_crt2(
      tl, &signer, 1, vdata, vdata_size, vflags, &vtmp, NULL);
    if (ret < 0 || vtmp != 0) {
      /* could not construct a valid chain */
      _gnutls_reason_log(
        "signer failed trust list verification", vtmp);
      gnutls_assert();
      goto fail;
    }
  }

  if (signer == NULL) {
    gnutls_assert();
    goto fail;
  }

  goto cleanup;

fail:
  if (signer != NULL) {
    if (issuer == signer)
      issuer = NULL;
    gnutls_x509_crt_deinit(signer);
    signer = NULL;
  }

cleanup:
  if (issuer != NULL) {
    gnutls_x509_crt_deinit(issuer);
    issuer = NULL;
  }
  gnutls_free(tmp.data);

  return signer;
}

/**
 * gnutls_pkcs7_verify:
 * @pkcs7: should contain a #gnutls_pkcs7_t type
 * @tl: A list of trusted certificates
 * @vdata: an array of typed data
 * @vdata_size: the number of data elements
 * @idx: the index of the signature info to check
 * @data: The data to be verified or %NULL
 * @flags: Zero or an OR list of #gnutls_certificate_verify_flags
 *
 * This function will verify the provided data against the signature
 * present in the SignedData of the PKCS #7 structure. If the data
 * provided are NULL then the data in the encapsulatedContent field
 * will be used instead.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value. A verification error results to a
 *   %GNUTLS_E_PK_SIG_VERIFY_FAILED and the lack of encapsulated data
 *   to verify to a %GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE.
 *
 * Since: 3.4.2
 **/
int gnutls_pkcs7_verify(gnutls_pkcs7_t pkcs7, gnutls_x509_trust_list_t tl,
      gnutls_typed_vdata_st *vdata, unsigned int vdata_size,
      unsigned idx, const gnutls_datum_t *data,
      unsigned flags)
{
  int count, ret;
  gnutls_datum_t tmpdata = { NULL, 0 };
  gnutls_pkcs7_signature_info_st info;
  gnutls_x509_crt_t signer;
  gnutls_datum_t sigdata = { NULL, 0 };
  char root[128];

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

  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  ret = asn1_number_of_elements(pkcs7->signed_data, "signerInfos",
              &count);
  if (ret != ASN1_SUCCESS || idx + 1 > (unsigned)count) {
    gnutls_assert();
    return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
  }

  /* read data */
  ret = gnutls_pkcs7_get_signature_info(pkcs7, idx, &info);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  snprintf(root, sizeof(root), "signerInfos.?%u", idx + 1);
  ret = figure_pkcs7_sigdata(pkcs7, root, data, info.algo, &sigdata);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  signer = find_signer(pkcs7, tl, vdata, vdata_size, flags, &info);
  if (signer) {
    ret = gnutls_x509_crt_verify_data3(signer, info.algo, vdata,
               vdata_size, &sigdata,
               &info.sig, flags);
    if (ret < 0) {
      _gnutls_cert_log("failed struct verification with",
           signer);
      gnutls_assert();
    }
    gnutls_x509_crt_deinit(signer);
  } else {
    gnutls_assert();
    ret = GNUTLS_E_PK_SIG_VERIFY_FAILED;
  }

cleanup:
  gnutls_free(tmpdata.data);
  gnutls_free(sigdata.data);
  gnutls_pkcs7_signature_info_deinit(&info);

  return ret;
}

static void disable_opt_fields(gnutls_pkcs7_t pkcs7)
{
  int result;
  int count;

  /* disable the optional fields */
  result = asn1_number_of_elements(pkcs7->signed_data, "crls", &count);
  if (result != ASN1_SUCCESS || count == 0) {
    (void)asn1_write_value(pkcs7->signed_data, "crls", NULL, 0);
  }

  result = asn1_number_of_elements(pkcs7->signed_data, "certificates",
           &count);
  if (result != ASN1_SUCCESS || count == 0) {
    (void)asn1_write_value(pkcs7->signed_data, "certificates", NULL,
               0);
  }

  return;
}

static int reencode(gnutls_pkcs7_t pkcs7)
{
  int result;

  if (pkcs7->signed_data != NULL) {
    disable_opt_fields(pkcs7);

    /* Replace the old content with the new
     */
    result = _gnutls_x509_der_encode_and_copy(
      pkcs7->signed_data, "", pkcs7->pkcs7, "content", 0);
    if (result < 0) {
      return gnutls_assert_val(result);
    }

    /* Write the content type of the signed data
     */
    result = asn1_write_value(pkcs7->pkcs7, "contentType",
            SIGNED_DATA_OID, 1);
    if (result != ASN1_SUCCESS) {
      gnutls_assert();
      return _gnutls_asn2err(result);
    }
  }
  return 0;
}

/**
 * gnutls_pkcs7_export:
 * @pkcs7: The pkcs7 type
 * @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)
{
  int ret;
  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  if ((ret = reencode(pkcs7)) < 0)
    return gnutls_assert_val(ret);

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

/**
 * gnutls_pkcs7_export2:
 * @pkcs7: The pkcs7 type
 * @format: the format of output params. One of PEM or DER.
 * @out: will contain a structure PEM or DER encoded
 *
 * This function will export the pkcs7 structure to DER or PEM format.
 *
 * The output buffer is allocated using gnutls_malloc().
 *
 * 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.
 *
 * Since: 3.1.3
 **/
int gnutls_pkcs7_export2(gnutls_pkcs7_t pkcs7, gnutls_x509_crt_fmt_t format,
       gnutls_datum_t *out)
{
  int ret;
  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  if ((ret = reencode(pkcs7)) < 0)
    return gnutls_assert_val(ret);

  return _gnutls_x509_export_int2(pkcs7->pkcs7, format, PEM_PKCS7, out);
}

/* 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_node pkcs7, asn1_node *sdata)
{
  int result;

  *sdata = NULL;

  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",
          DIGESTED_DATA_OID, 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.
   */

  return 0;

cleanup:
  asn1_delete_structure(sdata);
  return result;
}

/**
 * gnutls_pkcs7_set_crt_raw:
 * @pkcs7: The pkcs7 type
 * @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)
{
  int result;

  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

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

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

  result = asn1_write_value(pkcs7->signed_data, "certificates", "NEW", 1);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto cleanup;
  }

  result = asn1_write_value(pkcs7->signed_data, "certificates.?LAST",
          "certificate", 1);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto cleanup;
  }

  result = asn1_write_value(pkcs7->signed_data,
          "certificates.?LAST.certificate", crt->data,
          crt->size);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto cleanup;
  }

  result = 0;

cleanup:
  return result;
}

/**
 * gnutls_pkcs7_set_crt:
 * @pkcs7: The pkcs7 type
 * @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: The pkcs7 type
 * @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)
{
  int result;
  char root2[MAX_NAME_SIZE];

  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  /* Step 2. Delete the certificate.
   */

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

  result = asn1_write_value(pkcs7->signed_data, root2, NULL, 0);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto cleanup;
  }

  return 0;

cleanup:
  return result;
}

/* Read and write CRLs
 */

/**
 * gnutls_pkcs7_get_crl_raw2:
 * @pkcs7: The pkcs7 type
 * @indx: contains the index of the crl to extract
 * @crl: will contain the contents of the CRL in an allocated buffer
 *
 * This function will return a DER encoded CRL of the PKCS7 or RFC2630 crl set.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.  After the last crl has been read
 *   %GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.
 *
 * Since: 3.4.2
 **/
int gnutls_pkcs7_get_crl_raw2(gnutls_pkcs7_t pkcs7, unsigned indx,
            gnutls_datum_t *crl)
{
  int result;
  char root2[MAX_NAME_SIZE];
  gnutls_datum_t tmp = { NULL, 0 };
  int start, end;

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

  result = _gnutls_x509_read_value(pkcs7->pkcs7, "content", &tmp);
  if (result < 0) {
    gnutls_assert();
    goto cleanup;
  }

  /* Step 2. Parse the CertificateSet
   */

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

  /* Get the raw CRL
   */
  result = asn1_der_decoding_startEnd(pkcs7->signed_data, tmp.data,
              tmp.size, root2, &start, &end);

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

  end = end - start + 1;

  result = _gnutls_set_datum(crl, &tmp.data[start], end);

cleanup:
  _gnutls_free_datum(&tmp);
  return result;
}

/**
 * gnutls_pkcs7_get_crl_raw:
 * @pkcs7: The pkcs7 type
 * @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, unsigned indx, void *crl,
           size_t *crl_size)
{
  int ret;
  gnutls_datum_t tmp = { NULL, 0 };

  ret = gnutls_pkcs7_get_crl_raw2(pkcs7, indx, &tmp);
  if (ret < 0)
    return gnutls_assert_val(ret);

  if ((unsigned)tmp.size > *crl_size) {
    *crl_size = tmp.size;
    ret = GNUTLS_E_SHORT_MEMORY_BUFFER;
    goto cleanup;
  }

  assert(tmp.data != NULL);

  *crl_size = tmp.size;
  if (crl)
    memcpy(crl, tmp.data, tmp.size);

cleanup:
  _gnutls_free_datum(&tmp);
  return ret;
}

/**
 * gnutls_pkcs7_get_crl_count:
 * @pkcs7: The pkcs7 type
 *
 * This function will return the number of certificates 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)
{
  int result, count;

  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  /* Step 2. Count the CertificateSet */

  result = asn1_number_of_elements(pkcs7->signed_data, "crls", &count);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    return 0; /* no crls */
  }

  return count;
}

/**
 * gnutls_pkcs7_set_crl_raw:
 * @pkcs7: The pkcs7 type
 * @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)
{
  int result;

  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

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

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

  result = asn1_write_value(pkcs7->signed_data, "crls", "NEW", 1);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto cleanup;
  }

  result = asn1_write_value(pkcs7->signed_data, "crls.?LAST", crl->data,
          crl->size);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto cleanup;
  }

  result = 0;

cleanup:
  return result;
}

/**
 * gnutls_pkcs7_set_crl:
 * @pkcs7: The pkcs7 type
 * @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: The pkcs7 type
 * @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)
{
  int result;
  char root2[MAX_NAME_SIZE];

  if (pkcs7 == NULL)
    return GNUTLS_E_INVALID_REQUEST;

  /* Delete the crl.
   */

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

  result = asn1_write_value(pkcs7->signed_data, root2, NULL, 0);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto cleanup;
  }

  return 0;

cleanup:
  return result;
}

static int write_signer_id(asn1_node c2, const char *root,
         gnutls_x509_crt_t signer, unsigned flags)
{
  int result;
  size_t serial_size;
  uint8_t serial[128];
  char name[256];

  if (flags & GNUTLS_PKCS7_WRITE_SPKI) {
    const uint8_t ver = 3;

    snprintf(name, sizeof(name), "%s.version", root);
    result = asn1_write_value(c2, name, &ver, 1);
    if (result != ASN1_SUCCESS) {
      gnutls_assert();
      return _gnutls_asn2err(result);
    }

    snprintf(name, sizeof(name), "%s.sid", root);
    result = asn1_write_value(c2, name, "subjectKeyIdentifier", 1);
    if (result != ASN1_SUCCESS) {
      gnutls_assert();
      return _gnutls_asn2err(result);
    }

    serial_size = sizeof(serial);
    result = gnutls_x509_crt_get_subject_key_id(signer, serial,
                  &serial_size, NULL);
    if (result < 0)
      return gnutls_assert_val(result);

    snprintf(name, sizeof(name), "%s.subjectKeyIdentifier", root);
    result = asn1_write_value(c2, name, serial, serial_size);
    if (result != ASN1_SUCCESS) {
      gnutls_assert();
      return _gnutls_asn2err(result);
    }
  } else {
    serial_size = sizeof(serial);
    result = gnutls_x509_crt_get_serial(signer, serial,
                &serial_size);
    if (result < 0)
      return gnutls_assert_val(result);

    snprintf(name, sizeof(name), "%s.sid", root);
    result = asn1_write_value(c2, name, "issuerAndSerialNumber", 1);
    if (result != ASN1_SUCCESS) {
      gnutls_assert();
      return _gnutls_asn2err(result);
    }

    snprintf(name, sizeof(name),
       "%s.sid.issuerAndSerialNumber.serialNumber", root);
    result = asn1_write_value(c2, name, serial, serial_size);
    if (result != ASN1_SUCCESS) {
      gnutls_assert();
      return _gnutls_asn2err(result);
    }

    snprintf(name, sizeof(name),
       "%s.sid.issuerAndSerialNumber.issuer", root);
    result = asn1_copy_node(c2, name, signer->cert,
          "tbsCertificate.issuer");
    if (result != ASN1_SUCCESS) {
      gnutls_assert();
      return _gnutls_asn2err(result);
    }
  }

  return 0;
}

static int add_attrs(asn1_node c2, const char *root, gnutls_pkcs7_attrs_t attrs,
         unsigned already_set)
{
  char name[256];
  gnutls_pkcs7_attrs_st *p = attrs;
  int result;

  if (attrs == NULL) {
    /* if there are no other attributes delete that field */
    if (already_set == 0)
      (void)asn1_write_value(c2, root, NULL, 0);
  } else {
    while (p != NULL) {
      result = asn1_write_value(c2, root, "NEW", 1);
      if (result != ASN1_SUCCESS) {
        gnutls_assert();
        return _gnutls_asn2err(result);
      }

      snprintf(name, sizeof(name), "%s.?LAST.type", root);
      result = asn1_write_value(c2, name, p->oid, 1);
      if (result != ASN1_SUCCESS) {
        gnutls_assert();
        return _gnutls_asn2err(result);
      }

      snprintf(name, sizeof(name), "%s.?LAST.values", root);
      result = asn1_write_value(c2, name, "NEW", 1);
      if (result != ASN1_SUCCESS) {
        gnutls_assert();
        return _gnutls_asn2err(result);
      }

      snprintf(name, sizeof(name), "%s.?LAST.values.?1",
         root);
      result = asn1_write_value(c2, name, p->data.data,
              p->data.size);
      if (result != ASN1_SUCCESS) {
        gnutls_assert();
        return _gnutls_asn2err(result);
      }

      p = p->next;
    }
  }

  return 0;
}

static int write_attributes(asn1_node c2, const char *root,
          const gnutls_datum_t *data, const mac_entry_st *me,
          gnutls_pkcs7_attrs_t other_attrs, unsigned flags)
{
  char name[256];
  int result, ret;
  uint8_t digest[MAX_HASH_SIZE];
  gnutls_datum_t tmp = { NULL, 0 };
  unsigned digest_size;
  unsigned already_set = 0;

  if (flags & GNUTLS_PKCS7_INCLUDE_TIME) {
    if (data == NULL || data->data == NULL) {
      gnutls_assert();
      return GNUTLS_E_INVALID_REQUEST;
    }

    /* Add time */
    result = asn1_write_value(c2, root, "NEW", 1);
    if (result != ASN1_SUCCESS) {
      gnutls_assert();
      ret = _gnutls_asn2err(result);
      return ret;
    }

    snprintf(name, sizeof(name), "%s.?LAST.type", root);
    result = asn1_write_value(c2, name, ATTR_SIGNING_TIME, 1);
    if (result != ASN1_SUCCESS) {
      gnutls_assert();
      ret = _gnutls_asn2err(result);
      return ret;
    }

    snprintf(name, sizeof(name), "%s.?LAST.values", root);
    result = asn1_write_value(c2, name, "NEW", 1);
    if (result != ASN1_SUCCESS) {
      gnutls_assert();
      ret = _gnutls_asn2err(result);
      return ret;
    }

    snprintf(name, sizeof(name), "%s.?LAST.values.?1", root);
    ret = _gnutls_x509_set_raw_time(c2, name, gnutls_time(NULL));
    if (ret < 0) {
      gnutls_assert();
      return ret;
    }

    already_set = 1;
  }

  ret = add_attrs(c2, root, other_attrs, already_set);
  if (ret < 0) {
    gnutls_assert();
    return ret;
  }

  if (already_set != 0 || other_attrs != NULL) {
    /* Add content type */
    result = asn1_write_value(c2, root, "NEW", 1);
    if (result != ASN1_SUCCESS) {
      gnutls_assert();
      ret = _gnutls_asn2err(result);
      return ret;
    }

    snprintf(name, sizeof(name), "%s.?LAST.type", root);
    result = asn1_write_value(c2, name, ATTR_CONTENT_TYPE, 1);
    if (result != ASN1_SUCCESS) {
      gnutls_assert();
      ret = _gnutls_asn2err(result);
      return ret;
    }

    snprintf(name, sizeof(name), "%s.?LAST.values", root);
    result = asn1_write_value(c2, name, "NEW", 1);
    if (result != ASN1_SUCCESS) {
      gnutls_assert();
      ret = _gnutls_asn2err(result);
      return ret;
    }

    ret = _gnutls_x509_get_raw_field(
      c2, "encapContentInfo.eContentType", &tmp);
    if (ret < 0) {
      gnutls_assert();
      return ret;
    }

    snprintf(name, sizeof(name), "%s.?LAST.values.?1", root);
    result = asn1_write_value(c2, name, tmp.data, tmp.size);
    gnutls_free(tmp.data);

    if (result != ASN1_SUCCESS) {
      gnutls_assert();
      ret = _gnutls_asn2err(result);
      return ret;
    }

    /* If we add any attribute we should add them all */
    /* Add hash */
    digest_size = _gnutls_hash_get_algo_len(me);
    ret = gnutls_hash_fast(MAC_TO_DIG(me->id), data->data,
               data->size, digest);
    if (ret < 0) {
      gnutls_assert();
      return ret;
    }

    result = asn1_write_value(c2, root, "NEW", 1);
    if (result != ASN1_SUCCESS) {
      gnutls_assert();
      ret = _gnutls_asn2err(result);
      return ret;
    }

    snprintf(name, sizeof(name), "%s.?LAST", root);
    ret = _gnutls_x509_encode_and_write_attribute(
      ATTR_MESSAGE_DIGEST, c2, name, digest, digest_size, 1);
    if (ret < 0) {
      gnutls_assert();
      return ret;
    }
  }

  return 0;
}

/**
 * gnutls_pkcs7_sign:
 * @pkcs7: should contain a #gnutls_pkcs7_t type
 * @signer: the certificate to sign the structure
 * @signer_key: the key to sign the structure
 * @data: The data to be signed or %NULL if the data are already embedded
 * @signed_attrs: Any additional attributes to be included in the signed ones (or %NULL)
 * @unsigned_attrs: Any additional attributes to be included in the unsigned ones (or %NULL)
 * @dig: The digest algorithm to use for signing
 * @flags: Should be zero or one of %GNUTLS_PKCS7 flags
 *
 * This function will add a signature in the provided PKCS #7 structure
 * for the provided data. Multiple signatures can be made with different
 * signers.
 *
 * The available flags are:
 *  %GNUTLS_PKCS7_EMBED_DATA, %GNUTLS_PKCS7_INCLUDE_TIME, %GNUTLS_PKCS7_INCLUDE_CERT,
 *  and %GNUTLS_PKCS7_WRITE_SPKI. They are explained in the #gnutls_pkcs7_sign_flags
 *  definition.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.4.2
 **/
int gnutls_pkcs7_sign(gnutls_pkcs7_t pkcs7, gnutls_x509_crt_t signer,
          gnutls_privkey_t signer_key, const gnutls_datum_t *data,
          gnutls_pkcs7_attrs_t signed_attrs,
          gnutls_pkcs7_attrs_t unsigned_attrs,
          gnutls_digest_algorithm_t dig, unsigned flags)
{
  int ret, result;
  gnutls_datum_t sigdata = { NULL, 0 };
  gnutls_datum_t signature = { NULL, 0 };
  const mac_entry_st *me = hash_to_entry(dig);
  unsigned pk, sigalgo;
  gnutls_x509_spki_st key_params, params;
  const gnutls_sign_entry_st *se;

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

  if (pkcs7->signed_data == NULL) {
    result = asn1_create_element(_gnutls_get_pkix(),
               "PKIX1.pkcs-7-SignedData",
               &pkcs7->signed_data);
    if (result != ASN1_SUCCESS) {
      gnutls_assert();
      ret = _gnutls_asn2err(result);
      goto cleanup;
    }

    if (!(flags & GNUTLS_PKCS7_EMBED_DATA)) {
      (void)asn1_write_value(pkcs7->signed_data,
                 "encapContentInfo.eContent",
                 NULL, 0);
    }
  }

  result = asn1_write_value(pkcs7->signed_data, "version", &one, 1);
  if (result != ASN1_SUCCESS) {
    ret = _gnutls_asn2err(result);
    goto cleanup;
  }

  result = asn1_write_value(pkcs7->signed_data,
          "encapContentInfo.eContentType", DATA_OID, 0);
  if (result != ASN1_SUCCESS) {
    ret = _gnutls_asn2err(result);
    goto cleanup;
  }

  if ((flags & GNUTLS_PKCS7_EMBED_DATA) && data->data) { /* embed data */
    ret = _gnutls_x509_write_string(pkcs7->signed_data,
            "encapContentInfo.eContent",
            data, ASN1_ETYPE_OCTET_STRING);
    if (ret < 0) {
      goto cleanup;
    }
  }

  if (flags & GNUTLS_PKCS7_INCLUDE_CERT) {
    ret = gnutls_pkcs7_set_crt(pkcs7, signer);
    if (ret < 0) {
      gnutls_assert();
      goto cleanup;
    }
  }

  /* append digest info algorithm */
  result = asn1_write_value(pkcs7->signed_data, "digestAlgorithms", "NEW",
          1);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    ret = _gnutls_asn2err(result);
    goto cleanup;
  }

  result = asn1_write_value(pkcs7->signed_data,
          "digestAlgorithms.?LAST.algorithm",
          _gnutls_x509_digest_to_oid(me), 1);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    ret = _gnutls_asn2err(result);
    goto cleanup;
  }

  (void)asn1_write_value(pkcs7->signed_data,
             "digestAlgorithms.?LAST.parameters", NULL, 0);

  /* append signer's info */
  result = asn1_write_value(pkcs7->signed_data, "signerInfos", "NEW", 1);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    ret = _gnutls_asn2err(result);
    goto cleanup;
  }

  result = asn1_write_value(pkcs7->signed_data,
          "signerInfos.?LAST.version", &one, 1);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    ret = _gnutls_asn2err(result);
    goto cleanup;
  }

  result = asn1_write_value(pkcs7->signed_data,
          "signerInfos.?LAST.digestAlgorithm.algorithm",
          _gnutls_x509_digest_to_oid(me), 1);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    ret = _gnutls_asn2err(result);
    goto cleanup;
  }

  (void)asn1_write_value(pkcs7->signed_data,
             "signerInfos.?LAST.digestAlgorithm.parameters",
             NULL, 0);

  ret = write_signer_id(pkcs7->signed_data, "signerInfos.?LAST", signer,
            flags);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  ret = add_attrs(pkcs7->signed_data, "signerInfos.?LAST.unsignedAttrs",
      unsigned_attrs, 0);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  ret = write_attributes(pkcs7->signed_data,
             "signerInfos.?LAST.signedAttrs", data, me,
             signed_attrs, flags);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  disable_opt_fields(pkcs7);

  /* write the signature algorithm */
  pk = gnutls_x509_crt_get_pk_algorithm(signer, NULL);

  ret = _gnutls_privkey_get_spki_params(signer_key, &key_params);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  ret = _gnutls_x509_crt_get_spki_params(signer, &key_params, &params);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  ret = _gnutls_privkey_update_spki_params(signer_key, pk, dig, 0,
             &params);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  se = _gnutls_pk_to_sign_entry(params.pk, dig);
  if (se == NULL) {
    ret = gnutls_assert_val(
      GNUTLS_E_UNSUPPORTED_SIGNATURE_ALGORITHM);
    goto cleanup;
  }

  /* RFC5652 is silent on what the values would be and initially I assumed that
   * typical signature algorithms should be set. However RFC2315 (PKCS#7) mentions
   * that a generic RSA OID should be used. We switch to this "unexpected" value
   * because some implementations cannot cope with the "expected" signature values.
   */
  params.legacy = 1;
  ret = _gnutls_x509_write_sign_params(
    pkcs7->signed_data, "signerInfos.?LAST.signatureAlgorithm", se,
    &params);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  sigalgo = se->id;

  /* sign the data */
  ret = figure_pkcs7_sigdata(pkcs7, "signerInfos.?LAST", data, sigalgo,
           &sigdata);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  FIX_SIGN_PARAMS(params, flags, dig);

  ret = privkey_sign_and_hash_data(signer_key, se, &sigdata, &signature,
           &params);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  result = asn1_write_value(pkcs7->signed_data,
          "signerInfos.?LAST.signature", signature.data,
          signature.size);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    ret = _gnutls_asn2err(result);
    goto cleanup;
  }

  ret = 0;

cleanup:
  gnutls_free(sigdata.data);
  gnutls_free(signature.data);
  return ret;
}

Coverage Report

Created: 2026-11-12 07:00