/src/gnutls/lib/x509/common.c

Source
/*
 * Copyright (C) 2003-2014 Free Software Foundation, Inc.
 * Copyright (C) 2015-2016 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/>
 *
 */

#include "gnutls_int.h"
#include <libtasn1.h>
#include "datum.h"
#include "global.h"
#include "errors.h"
#include "str.h"
#include "x509.h"
#include "num.h"
#include "x509_b64.h"
#include <c-strcase.h>
#include "intprops.h"
#include "x509_int.h"
#include "extras/hex.h"
#include "common.h"

static int data2hex(const void *data, size_t data_size, gnutls_datum_t *out);

#define ENTRY(oid, ldap, asn, etype) \
  { oid, sizeof(oid) - 1, ldap, sizeof(ldap) - 1, asn, etype }

/* when there is no name description */
#define ENTRY_ND(oid, asn, etype) { oid, sizeof(oid) - 1, NULL, 0, asn, etype }

/* This list contains all the OIDs that may be
 * contained in a rdnSequence and are printable.
 */
static const struct oid_to_string _oid2str[] = {
  /* PKIX
   */
  ENTRY("1.3.6.1.5.5.7.9.2", "placeOfBirth", "PKIX1.DirectoryString",
        ASN1_ETYPE_INVALID),
  ENTRY("1.3.6.1.5.5.7.9.3", "gender", NULL, ASN1_ETYPE_PRINTABLE_STRING),
  ENTRY("1.3.6.1.5.5.7.9.4", "countryOfCitizenship", NULL,
        ASN1_ETYPE_PRINTABLE_STRING),
  ENTRY("1.3.6.1.5.5.7.9.5", "countryOfResidence", NULL,
        ASN1_ETYPE_PRINTABLE_STRING),

  ENTRY("2.5.4.6", "C", NULL, ASN1_ETYPE_PRINTABLE_STRING),
  ENTRY("2.5.4.9", "street", "PKIX1.DirectoryString", ASN1_ETYPE_INVALID),
  ENTRY("2.5.4.12", "title", "PKIX1.DirectoryString", ASN1_ETYPE_INVALID),
  ENTRY("2.5.4.10", "O", "PKIX1.DirectoryString", ASN1_ETYPE_INVALID),
  ENTRY("2.5.4.11", "OU", "PKIX1.DirectoryString", ASN1_ETYPE_INVALID),
  ENTRY("2.5.4.3", "CN", "PKIX1.DirectoryString", ASN1_ETYPE_INVALID),
  ENTRY("2.5.4.7", "L", "PKIX1.DirectoryString", ASN1_ETYPE_INVALID),
  ENTRY("2.5.4.8", "ST", "PKIX1.DirectoryString", ASN1_ETYPE_INVALID),
  ENTRY("2.5.4.13", "description", "PKIX1.DirectoryString",
        ASN1_ETYPE_INVALID),

  ENTRY("2.5.4.5", "serialNumber", NULL, ASN1_ETYPE_PRINTABLE_STRING),
  ENTRY("2.5.4.20", "telephoneNumber", NULL, ASN1_ETYPE_PRINTABLE_STRING),
  ENTRY("2.5.4.4", "surName", "PKIX1.DirectoryString",
        ASN1_ETYPE_INVALID),
  ENTRY("2.5.4.43", "initials", "PKIX1.DirectoryString",
        ASN1_ETYPE_INVALID),
  ENTRY("2.5.4.44", "generationQualifier", "PKIX1.DirectoryString",
        ASN1_ETYPE_INVALID),
  ENTRY("2.5.4.42", "givenName", "PKIX1.DirectoryString",
        ASN1_ETYPE_INVALID),
  ENTRY("2.5.4.65", "pseudonym", "PKIX1.DirectoryString",
        ASN1_ETYPE_INVALID),
  ENTRY("2.5.4.46", "dnQualifier", NULL, ASN1_ETYPE_PRINTABLE_STRING),
  ENTRY("2.5.4.17", "postalCode", "PKIX1.DirectoryString",
        ASN1_ETYPE_INVALID),
  ENTRY("2.5.4.41", "name", "PKIX1.DirectoryString", ASN1_ETYPE_INVALID),
  ENTRY("2.5.4.15", "businessCategory", "PKIX1.DirectoryString",
        ASN1_ETYPE_INVALID),

  ENTRY("0.9.2342.19200300.100.1.25", "DC", NULL, ASN1_ETYPE_IA5_STRING),
  ENTRY("0.9.2342.19200300.100.1.1", "UID", "PKIX1.DirectoryString",
        ASN1_ETYPE_INVALID),
  ENTRY("1.2.840.113556.1.4.656", "userPrincipalName",
        "PKIX1.DirectoryString", ASN1_ETYPE_INVALID),

  /* Extended validation
   */
  ENTRY("1.3.6.1.4.1.311.60.2.1.1",
        "jurisdictionOfIncorporationLocalityName",
        "PKIX1.DirectoryString", ASN1_ETYPE_INVALID),
  ENTRY("1.3.6.1.4.1.311.60.2.1.2",
        "jurisdictionOfIncorporationStateOrProvinceName",
        "PKIX1.DirectoryString", ASN1_ETYPE_INVALID),
  ENTRY("1.3.6.1.4.1.311.60.2.1.3",
        "jurisdictionOfIncorporationCountryName", NULL,
        ASN1_ETYPE_PRINTABLE_STRING),

  /* PKCS #9
   */
  ENTRY("1.2.840.113549.1.9.1", "EMAIL", NULL, ASN1_ETYPE_IA5_STRING),
  ENTRY_ND("1.2.840.113549.1.9.7", "PKIX1.pkcs-9-challengePassword",
     ASN1_ETYPE_INVALID),

  /* friendly name */
  ENTRY_ND("1.2.840.113549.1.9.20", NULL, ASN1_ETYPE_BMP_STRING),
  /* local key id */
  ENTRY_ND("1.2.840.113549.1.9.21", NULL, ASN1_ETYPE_OCTET_STRING),
  ENTRY_ND("1.2.840.113549.1.9.4", NULL, ASN1_ETYPE_OCTET_STRING),

  /* rfc3920 section 5.1.1 */
  ENTRY("1.3.6.1.5.5.7.8.5", "XmppAddr", NULL, ASN1_ETYPE_UTF8_STRING),

  /* Russian things: https://cdnimg.rg.ru/pril/66/91/91/23041_pril.pdf */
  /* Main state registration number */
  ENTRY("1.2.643.100.1", "OGRN", NULL, ASN1_ETYPE_NUMERIC_STRING),
  /* Individual insurance account number */
  ENTRY("1.2.643.100.3", "SNILS", NULL, ASN1_ETYPE_NUMERIC_STRING),
  /* Main state registration number for individual enterpreneurs */
  ENTRY("1.2.643.100.5", "OGRNIP", NULL, ASN1_ETYPE_NUMERIC_STRING),
  /* VAT identification number */
  ENTRY("1.2.643.3.131.1.1", "INN", NULL, ASN1_ETYPE_NUMERIC_STRING),

  { NULL, 0, NULL, 0, NULL, 0 }
};

const struct oid_to_string *
_gnutls_oid_get_entry(const struct oid_to_string *ots, const char *oid)
{
  unsigned int i = 0;
  unsigned len = strlen(oid);

  do {
    if (len == ots[i].oid_size && strcmp(ots[i].oid, oid) == 0)
      return &ots[i];
    i++;
  } while (ots[i].oid != NULL);

  return NULL;
}

const char *_gnutls_oid_get_asn_desc(const char *oid)
{
  const struct oid_to_string *entry =
    _gnutls_oid_get_entry(_oid2str, oid);
  return entry ? entry->asn_desc : NULL;
}

const char *_gnutls_ldap_string_to_oid(const char *str, unsigned str_len)
{
  unsigned int i = 0;

  do {
    if ((_oid2str[i].name_desc != NULL) &&
        (str_len == _oid2str[i].name_desc_size) &&
        (c_strncasecmp(_oid2str[i].name_desc, str, str_len) == 0))
      return _oid2str[i].oid;
    i++;
  } while (_oid2str[i].oid != NULL);

  return NULL;
}

/* Escapes a string following the rules from RFC4514.
 */
static int str_escape(const gnutls_datum_t *str, gnutls_datum_t *escaped)
{
  unsigned int j, i;
  uint8_t *buffer = NULL;
  size_t size;
  int ret;

  if (str == NULL)
    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

  /* the string will be at most twice the original */
  if (!INT_MULTIPLY_OK(str->size, 2, &size) ||
      !INT_ADD_OK(size, 2, &size))
    return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);

  buffer = gnutls_malloc(size);
  if (buffer == NULL)
    return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);

  for (i = j = 0; i < str->size; i++) {
    if (str->data[i] == 0) {
      /* this is handled earlier */
      ret = gnutls_assert_val(GNUTLS_E_ASN1_DER_ERROR);
      goto cleanup;
    }

    if (str->data[i] == ',' || str->data[i] == '+' ||
        str->data[i] == '"' || str->data[i] == '\\' ||
        str->data[i] == '<' || str->data[i] == '>' ||
        str->data[i] == ';' || str->data[i] == 0)
      buffer[j++] = '\\';
    else if (i == 0 && str->data[i] == '#')
      buffer[j++] = '\\';
    else if (i == 0 && str->data[i] == ' ')
      buffer[j++] = '\\';
    else if (i == (str->size - 1) && str->data[i] == ' ')
      buffer[j++] = '\\';

    buffer[j++] = str->data[i];
  }

  /* null terminate the string */
  buffer[j] = 0;
  escaped->data = buffer;
  escaped->size = j;

  return 0;
cleanup:
  gnutls_free(buffer);
  return ret;
}

/**
 * gnutls_x509_dn_oid_known:
 * @oid: holds an Object Identifier in a null terminated string
 *
 * This function will inform about known DN OIDs. This is useful since
 * functions like gnutls_x509_crt_set_dn_by_oid() use the information
 * on known OIDs to properly encode their input. Object Identifiers
 * that are not known are not encoded by these functions, and their
 * input is stored directly into the ASN.1 structure. In that case of
 * unknown OIDs, you have the responsibility of DER encoding your
 * data.
 *
 * Returns: 1 on known OIDs and 0 otherwise.
 **/
int gnutls_x509_dn_oid_known(const char *oid)
{
  return _gnutls_oid_get_entry(_oid2str, oid) != NULL;
}

/**
 * gnutls_x509_dn_oid_name:
 * @oid: holds an Object Identifier in a null terminated string
 * @flags: 0 or GNUTLS_X509_DN_OID_*
 *
 * This function will return the name of a known DN OID. If
 * %GNUTLS_X509_DN_OID_RETURN_OID is specified this function
 * will return the given OID if no descriptive name has been
 * found.
 *
 * Returns: A null terminated string or NULL otherwise.
 *
 * Since: 3.0
 **/
const char *gnutls_x509_dn_oid_name(const char *oid, unsigned int flags)
{
  const struct oid_to_string *entry =
    _gnutls_oid_get_entry(_oid2str, oid);

  if (entry && entry->name_desc)
    return entry->name_desc;
  if (flags & GNUTLS_X509_DN_OID_RETURN_OID)
    return oid;
  else
    return NULL;
}

static int make_printable_string(unsigned etype, const gnutls_datum_t *input,
         gnutls_datum_t *out)
{
  int printable = 0;
  int ret;

  /* empty input strings result to a null string */
  if (input->data == NULL || input->size == 0) {
    out->data = gnutls_calloc(1, 1);
    if (out->data == NULL)
      return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);
    out->size = 0;
    return 0;
  }

  if (etype == ASN1_ETYPE_BMP_STRING) {
    ret = _gnutls_ucs2_to_utf8(input->data, input->size, out, 1);
    if (ret < 0) {
      /* could not convert. Handle it as non-printable */
      printable = 0;
    } else
      printable = 1;
  } else if (etype == ASN1_ETYPE_TELETEX_STRING) {
    /* HACK: if the teletex string contains only ascii
     * characters then treat it as printable.
     */
    if (_gnutls_str_is_print((char *)input->data, input->size)) {
      out->data = gnutls_malloc(input->size + 1);
      if (out->data == NULL)
        return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);

      memcpy(out->data, input->data, input->size);
      out->size = input->size;

      out->data[out->size] = 0;

      printable = 1;
    }
  } else if (etype !=
       ASN1_ETYPE_UNIVERSAL_STRING) /* supported but not printable */
    return GNUTLS_E_INVALID_REQUEST;

  if (printable == 0) { /* need to allocate out */
    ret = data2hex(input->data, input->size, out);
    if (ret < 0) {
      gnutls_assert();
      return ret;
    }
  }

  return 0;
}

static int decode_complex_string(const struct oid_to_string *oentry,
         void *value, int value_size,
         gnutls_datum_t *out)
{
  char str[MAX_STRING_LEN], tmpname[128];
  int len = -1, result;
  asn1_node tmpasn = NULL;
  char asn1_err[ASN1_MAX_ERROR_DESCRIPTION_SIZE] = "";
  unsigned int etype;
  gnutls_datum_t td = { NULL, 0 };

  if (oentry->asn_desc == NULL) {
    gnutls_assert();
    return GNUTLS_E_INTERNAL_ERROR;
  }

  if ((result = asn1_create_element(_gnutls_get_pkix(), oentry->asn_desc,
            &tmpasn)) != ASN1_SUCCESS) {
    gnutls_assert();
    return _gnutls_asn2err(result);
  }

  if ((result = _asn1_strict_der_decode(&tmpasn, value, value_size,
                asn1_err)) != ASN1_SUCCESS) {
    gnutls_assert();
    _gnutls_debug_log("_asn1_strict_der_decode: %s\n", asn1_err);
    asn1_delete_structure(&tmpasn);
    return _gnutls_asn2err(result);
  }

  /* Read the type of choice.
   */
  len = sizeof(str) - 1;
  if ((result = asn1_read_value(tmpasn, "", str, &len)) !=
      ASN1_SUCCESS) { /* CHOICE */
    gnutls_assert();
    asn1_delete_structure(&tmpasn);
    return _gnutls_asn2err(result);
  }

  str[len] = 0;

  /* We set the etype on the strings that may need
   * some conversion to UTF-8. The INVALID flag indicates
   * no conversion needed */
  if (strcmp(str, "teletexString") == 0)
    etype = ASN1_ETYPE_TELETEX_STRING;
  else if (strcmp(str, "bmpString") == 0)
    etype = ASN1_ETYPE_BMP_STRING;
  else if (strcmp(str, "universalString") == 0)
    etype = ASN1_ETYPE_UNIVERSAL_STRING;
  else
    etype = ASN1_ETYPE_INVALID;

  _gnutls_str_cpy(tmpname, sizeof(tmpname), str);

  result = _gnutls_x509_read_value(tmpasn, tmpname, &td);
  asn1_delete_structure(&tmpasn);
  if (result < 0)
    return gnutls_assert_val(result);

  if (etype != ASN1_ETYPE_INVALID) {
    result = make_printable_string(etype, &td, out);

    _gnutls_free_datum(&td);

    if (result < 0)
      return gnutls_assert_val(result);
  } else {
    out->data = td.data;
    out->size = td.size;
    /* _gnutls_x509_read_value always null terminates */
  }

  assert(out->data != NULL);

  /* Refuse to deal with strings containing NULs. */
  if (strlen((void *)out->data) != (size_t)out->size) {
    _gnutls_free_datum(out);
    return gnutls_assert_val(GNUTLS_E_ASN1_EMBEDDED_NULL_IN_STRING);
  }

  return 0;
}

/* This function will convert an attribute value, specified by the OID,
 * to a string. The result will be a null terminated string.
 *
 * res may be null. This will just return the res_size, needed to
 * hold the string.
 */
int _gnutls_x509_dn_to_string(const char *oid, void *value, int value_size,
            gnutls_datum_t *str)
{
  const struct oid_to_string *oentry;
  int ret;
  gnutls_datum_t tmp = { NULL, 0 };

  if (value == NULL || value_size <= 0) {
    gnutls_assert();
    return GNUTLS_E_INVALID_REQUEST;
  }

  oentry = _gnutls_oid_get_entry(_oid2str, oid);
  if (oentry == NULL) { /* unknown OID -> hex */
  unknown_oid:
    ret = data2hex(value, value_size, str);
    if (ret < 0) {
      gnutls_assert();
      return ret;
    }
    return 0;
  }

  if (oentry->asn_desc != NULL) { /* complex */
    ret = decode_complex_string(oentry, value, value_size, &tmp);
    if (ret < 0) {
      /* we failed decoding -> handle it as unknown OID */
      goto unknown_oid;
    }
  } else {
    ret = _gnutls_x509_decode_string(oentry->etype, value,
             value_size, &tmp, 0);
    if (ret < 0) {
      /* we failed decoding -> handle it as unknown OID */
      goto unknown_oid;
    }
  }

  ret = str_escape(&tmp, str);
  _gnutls_free_datum(&tmp);

  if (ret < 0)
    return gnutls_assert_val(ret);

  return 0;
}

/* Converts a data string to an LDAP rfc2253 hex string
 * something like '#01020304'
 */
static int data2hex(const void *data, size_t data_size, gnutls_datum_t *out)
{
  gnutls_datum_t tmp, td;
  int ret;
  size_t size;

  td.size = hex_str_size(data_size) + 1; /* +1 for '#' */
  td.data = gnutls_malloc(td.size);
  if (td.data == NULL)
    return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);

  tmp.data = (void *)data;
  tmp.size = data_size;

  td.data[0] = '#';
  size = td.size - 1; /* don't include '#' */
  ret = gnutls_hex_encode(&tmp, (char *)&td.data[1], &size);
  if (ret < 0) {
    gnutls_assert();
    gnutls_free(td.data);
    return GNUTLS_E_SHORT_MEMORY_BUFFER;
  }

  td.size--; /* don't include null */

  out->data = td.data;
  out->size = td.size;

  return 0;
}

gnutls_x509_subject_alt_name_t _gnutls_x509_san_find_type(char *str_type)
{
  if (strcmp(str_type, "dNSName") == 0)
    return GNUTLS_SAN_DNSNAME;
  if (strcmp(str_type, "rfc822Name") == 0)
    return GNUTLS_SAN_RFC822NAME;
  if (strcmp(str_type, "uniformResourceIdentifier") == 0)
    return GNUTLS_SAN_URI;
  if (strcmp(str_type, "iPAddress") == 0)
    return GNUTLS_SAN_IPADDRESS;
  if (strcmp(str_type, "otherName") == 0)
    return GNUTLS_SAN_OTHERNAME;
  if (strcmp(str_type, "directoryName") == 0)
    return GNUTLS_SAN_DN;
  if (strcmp(str_type, "registeredID") == 0)
    return GNUTLS_SAN_REGISTERED_ID;

  return (gnutls_x509_subject_alt_name_t)-1;
}

/* A generic export function. Will export the given ASN.1 encoded data
 * to PEM or DER raw data.
 */
int _gnutls_x509_export_int_named(asn1_node asn1_data, const char *name,
          gnutls_x509_crt_fmt_t format,
          const char *pem_header,
          unsigned char *output_data,
          size_t *output_data_size)
{
  int ret;
  gnutls_datum_t out = { NULL, 0 };
  size_t size;

  ret = _gnutls_x509_export_int_named2(asn1_data, name, format,
               pem_header, &out);
  if (ret < 0)
    return gnutls_assert_val(ret);

  if (format == GNUTLS_X509_FMT_PEM)
    size = out.size + 1;
  else
    size = out.size;

  if (*output_data_size < size) {
    *output_data_size = size;
    ret = gnutls_assert_val(GNUTLS_E_SHORT_MEMORY_BUFFER);
    goto cleanup;
  }

  *output_data_size = (size_t)out.size;
  if (output_data) {
    if (out.size > 0) {
      memcpy(output_data, out.data, (size_t)out.size);
    }
    if (format == GNUTLS_X509_FMT_PEM)
      output_data[out.size] = 0;
  }

  ret = 0;

cleanup:
  gnutls_free(out.data);

  return ret;
}

/* A generic export function. Will export the given ASN.1 encoded data
 * to PEM or DER raw data.
 */
int _gnutls_x509_export_int_named2(asn1_node asn1_data, const char *name,
           gnutls_x509_crt_fmt_t format,
           const char *pem_header, gnutls_datum_t *out)
{
  int ret;

  if (format == GNUTLS_X509_FMT_DER) {
    ret = _gnutls_x509_der_encode(asn1_data, name, out, 0);
    if (ret < 0)
      return gnutls_assert_val(ret);
  } else { /* PEM */
    gnutls_datum_t tmp;

    ret = _gnutls_x509_der_encode(asn1_data, name, &tmp, 0);
    if (ret < 0)
      return gnutls_assert_val(ret);

    ret = _gnutls_fbase64_encode(pem_header, tmp.data, tmp.size,
               out);
    _gnutls_free_datum(&tmp);

    if (ret < 0)
      return gnutls_assert_val(ret);
  }

  return 0;
}

/* Decodes an octet string. The etype specifies the string type.
 * The returned string is always null terminated (but null is not
 * included in size).
 */
int _gnutls_x509_decode_string(unsigned int etype, const uint8_t *der,
             size_t der_size, gnutls_datum_t *output,
             unsigned allow_ber)
{
  long ret;
  uint8_t *str;
  unsigned int str_size, len;
  gnutls_datum_t td;
  int tag_len, len_len;
  unsigned char class;
  unsigned long tag;

  output->data = NULL;
  output->size = 0;

  /* asn1_decode_simple_{ber,der} don't accept empty string,
   * check it beforehand.
   */
  ret = asn1_get_tag_der(der, der_size, &class, &tag_len, &tag);
  if (ret != ASN1_SUCCESS) {
    gnutls_assert();
    ret = _gnutls_asn2err(ret);
    return ret;
  }

  if (allow_ber)
    ret = asn1_get_length_ber(der + tag_len, der_size - tag_len,
            &len_len);
  else
    ret = asn1_get_length_der(der + tag_len, der_size - tag_len,
            &len_len);
  if (ret == 0) {
    output->data = NULL;
    output->size = 0;
    return 0;
  }

  if (allow_ber)
    ret = asn1_decode_simple_ber(etype, der, der_size, &str,
               &str_size, NULL);
  else
    ret = asn1_decode_simple_der(etype, der, der_size,
               (const uint8_t **)&str, &str_size);
  if (ret != ASN1_SUCCESS) {
    gnutls_assert();
    ret = _gnutls_asn2err(ret);
    return ret;
  }

  td.size = str_size;
  td.data = gnutls_malloc(str_size + 1);
  if (td.data == NULL)
    return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);

  if (str_size > 0)
    memcpy(td.data, str, str_size);
  td.data[str_size] = 0;

  if (allow_ber)
    free(str);

  ret = make_printable_string(etype, &td, output);
  if (ret == GNUTLS_E_INVALID_REQUEST) { /* unsupported etype */
    output->data = td.data;
    output->size = td.size;
    ret = 0;
  } else if (ret <= 0) {
    _gnutls_free_datum(&td);
  }

  /* Refuse to deal with strings containing NULs. */
  if (etype != ASN1_ETYPE_OCTET_STRING) {
    if (output->data)
      len = strlen((void *)output->data);
    else
      len = 0;

    if (len != (size_t)output->size) {
      _gnutls_free_datum(output);
      ret = gnutls_assert_val(
        GNUTLS_E_ASN1_EMBEDDED_NULL_IN_STRING);
    }
  }

  return ret;
}

/* Reads a value from an ASN1 tree, and puts the output
 * in an allocated variable in the given datum.
 *
 * Note that this function always allocates one plus
 * the required data size (and places a null byte).
 */
static int x509_read_value(asn1_node c, const char *root, gnutls_datum_t *ret,
         unsigned allow_null)
{
  int len = 0, result;
  uint8_t *tmp = NULL;
  unsigned int etype;

  result = asn1_read_value_type(c, root, NULL, &len, &etype);
  if (result == 0 && allow_null == 0 && len == 0) {
    /* don't allow null strings */
    return gnutls_assert_val(GNUTLS_E_ASN1_DER_ERROR);
  } else if (result == 0 && allow_null == 0 &&
       etype == ASN1_ETYPE_OBJECT_ID && len == 1) {
    return gnutls_assert_val(GNUTLS_E_ASN1_DER_ERROR);
  }

  if (result != ASN1_MEM_ERROR) {
    if (result != ASN1_SUCCESS || allow_null == 0 || len != 0) {
      result = _gnutls_asn2err(result);
      return result;
    }
  }

  if (etype == ASN1_ETYPE_BIT_STRING) {
    len = (len + 7) / 8;
  }

  tmp = gnutls_malloc((size_t)len + 1);
  if (tmp == NULL) {
    gnutls_assert();
    result = GNUTLS_E_MEMORY_ERROR;
    goto cleanup;
  }

  if (len > 0) {
    result = asn1_read_value(c, root, tmp, &len);
    if (result != ASN1_SUCCESS) {
      gnutls_assert();
      result = _gnutls_asn2err(result);
      goto cleanup;
    }

    switch (etype) {
    case ASN1_ETYPE_BIT_STRING:
      ret->size = (len + 7) / 8;
      break;
    case ASN1_ETYPE_OBJECT_ID:
      if (len > 0) {
        ret->size = len - 1;
      } else {
        result = gnutls_assert_val(
          GNUTLS_E_ASN1_DER_ERROR);
        goto cleanup;
      }
      break;
    default:
      ret->size = (unsigned)len;
      break;
    }
  } else {
    ret->size = 0;
  }

  tmp[ret->size] = 0;
  ret->data = tmp;

  return 0;

cleanup:
  gnutls_free(tmp);
  return result;
}

int _gnutls_x509_read_value(asn1_node c, const char *root, gnutls_datum_t *ret)
{
  return x509_read_value(c, root, ret, 0);
}

int _gnutls_x509_read_null_value(asn1_node c, const char *root,
         gnutls_datum_t *ret)
{
  return x509_read_value(c, root, ret, 1);
}

/* Reads a value from an ASN1 tree, then interprets it as the provided
 * type of string and returns the output in an allocated variable.
 *
 * Note that this function always places a null character
 * at the end of a readable string value (which is not accounted into size)
 */
int _gnutls_x509_read_string(asn1_node c, const char *root, gnutls_datum_t *ret,
           unsigned int etype, unsigned int allow_ber)
{
  int len = 0, result;
  size_t slen;
  uint8_t *tmp = NULL;
  unsigned rtype;

  result = asn1_read_value_type(c, root, NULL, &len, &rtype);
  if (result != ASN1_MEM_ERROR) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    return result;
  }

  if (rtype == ASN1_ETYPE_BIT_STRING)
    len /= 8;

  tmp = gnutls_malloc((size_t)len + 1);
  if (tmp == NULL) {
    gnutls_assert();
    result = GNUTLS_E_MEMORY_ERROR;
    goto cleanup;
  }

  result = asn1_read_value(c, root, tmp, &len);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto cleanup;
  }

  if (rtype == ASN1_ETYPE_BIT_STRING)
    len /= 8;

  /* Extract the STRING.
   */
  slen = (size_t)len;

  result = _gnutls_x509_decode_string(etype, tmp, slen, ret, allow_ber);
  if (result < 0) {
    gnutls_assert();
    goto cleanup;
  }
  gnutls_free(tmp);

  return 0;

cleanup:
  gnutls_free(tmp);
  return result;
}

/* The string type should be IA5String, UTF8String etc. Leave
 * null for octet string */
int _gnutls_x509_encode_string(unsigned int etype, const void *input_data,
             size_t input_size, gnutls_datum_t *output)
{
  uint8_t tl[ASN1_MAX_TL_SIZE];
  unsigned int tl_size;
  int ret;

  tl_size = sizeof(tl);
  ret = asn1_encode_simple_der(etype, input_data, input_size, tl,
             &tl_size);
  if (ret != ASN1_SUCCESS) {
    gnutls_assert();
    ret = _gnutls_asn2err(ret);
    return ret;
  }

  output->data = gnutls_malloc(tl_size + input_size);
  if (output->data == NULL)
    return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);

  memcpy(output->data, tl, tl_size);
  memcpy(output->data + tl_size, input_data, input_size);

  output->size = tl_size + input_size;

  return 0;
}

/* DER Encodes the src asn1_node and stores it to
 * the given datum. If str is non zero then the data are encoded as
 * an OCTET STRING.
 */
int _gnutls_x509_der_encode(asn1_node src, const char *src_name,
          gnutls_datum_t *res, int str)
{
  int size, result;
  int asize;
  uint8_t *data = NULL;
  asn1_node c2 = NULL;

  size = 0;
  result = asn1_der_coding(src, src_name, NULL, &size, NULL);
  /* this check explicitly covers the case where size == 0 && result == 0 */
  if (result != ASN1_MEM_ERROR) {
    gnutls_assert();
    return _gnutls_asn2err(result);
  }

  /* allocate data for the der
   */

  if (str)
    size += 16; /* for later to include the octet tags */
  asize = size;

  data = gnutls_malloc((size_t)size);
  if (data == NULL) {
    gnutls_assert();
    return GNUTLS_E_MEMORY_ERROR;
  }

  result = asn1_der_coding(src, src_name, data, &size, NULL);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto cleanup;
  }

  if (str) {
    if ((result = asn1_create_element(_gnutls_get_pkix(),
              "PKIX1.pkcs-7-Data", &c2)) !=
        ASN1_SUCCESS) {
      gnutls_assert();
      result = _gnutls_asn2err(result);
      goto cleanup;
    }

    result = asn1_write_value(c2, "", data, size);
    if (result != ASN1_SUCCESS) {
      gnutls_assert();
      result = _gnutls_asn2err(result);
      goto cleanup;
    }

    result = asn1_der_coding(c2, "", data, &asize, NULL);
    if (result != ASN1_SUCCESS) {
      gnutls_assert();
      result = _gnutls_asn2err(result);
      goto cleanup;
    }

    size = asize;

    asn1_delete_structure(&c2);
  }

  res->data = data;
  res->size = (unsigned)size;
  return 0;

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

/* DER Encodes the src asn1_node and stores it to
 * dest in dest_name. Useful to encode something and store it
 * as OCTET. If str is non null then the data are encoded as
 * an OCTET STRING.
 */
int _gnutls_x509_der_encode_and_copy(asn1_node src, const char *src_name,
             asn1_node dest, const char *dest_name,
             int str)
{
  int result;
  gnutls_datum_t encoded = { NULL, 0 };

  result = _gnutls_x509_der_encode(src, src_name, &encoded, str);

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

  /* Write the data.
   */
  result = asn1_write_value(dest, dest_name, encoded.data,
          (int)encoded.size);

  _gnutls_free_datum(&encoded);

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

  return 0;
}

/* Writes the value of the datum in the given asn1_node.
 */
int _gnutls_x509_write_value(asn1_node c, const char *root,
           const gnutls_datum_t *data)
{
  int ret;

  /* Write the data.
   */
  ret = asn1_write_value(c, root, data->data, data->size);
  if (ret != ASN1_SUCCESS) {
    gnutls_assert();
    return _gnutls_asn2err(ret);
  }

  return 0;
}

/* Writes the value of the datum in the given asn1_node as a string.
 */
int _gnutls_x509_write_string(asn1_node c, const char *root,
            const gnutls_datum_t *data, unsigned int etype)
{
  int ret;
  gnutls_datum_t val = { NULL, 0 };

  ret = _gnutls_x509_encode_string(etype, data->data, data->size, &val);
  if (ret < 0)
    return gnutls_assert_val(ret);

  /* Write the data.
   */
  ret = asn1_write_value(c, root, val.data, val.size);
  if (ret != ASN1_SUCCESS) {
    gnutls_assert();
    ret = _gnutls_asn2err(ret);
    goto cleanup;
  }

  ret = 0;

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

void _asnstr_append_name(char *name, size_t name_size, const char *part1,
       const char *part2)
{
  if (part1[0] != 0) {
    _gnutls_str_cpy(name, name_size, part1);
    _gnutls_str_cat(name, name_size, part2);
  } else
    _gnutls_str_cpy(name, name_size,
        part2 + 1 /* remove initial dot */);
}

/* Encodes and copies the private key parameters into a
 * subjectPublicKeyInfo structure.
 *
 */
int _gnutls_x509_encode_and_copy_PKI_params(asn1_node dst, const char *dst_name,
              const gnutls_pk_params_st *params)
{
  const char *oid;
  gnutls_datum_t der = { NULL, 0 };
  int result;
  char name[128];

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

  /* write the OID
   */
  _asnstr_append_name(name, sizeof(name), dst_name,
          ".algorithm.algorithm");

  result = asn1_write_value(dst, name, oid, 1);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    return _gnutls_asn2err(result);
  }

  result = _gnutls_x509_write_pubkey_params(params, &der);
  if (result < 0) {
    gnutls_assert();
    return result;
  }

  _asnstr_append_name(name, sizeof(name), dst_name,
          ".algorithm.parameters");

  result = asn1_write_value(dst, name, der.data, der.size);
  _gnutls_free_datum(&der);

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

  result = _gnutls_x509_write_pubkey(params, &der);
  if (result < 0) {
    gnutls_assert();
    return result;
  }

  /* Write the DER parameters. (in bits)
   */
  _asnstr_append_name(name, sizeof(name), dst_name, ".subjectPublicKey");
  result = asn1_write_value(dst, name, der.data, der.size * 8);
  _gnutls_free_datum(&der);

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

  return 0;
}

/* Encodes and public key parameters into a
 * subjectPublicKeyInfo structure and stores it in der.
 */
int _gnutls_x509_encode_PKI_params(gnutls_datum_t *der,
           const gnutls_pk_params_st *params)
{
  int ret;
  asn1_node tmp;

  ret = asn1_create_element(_gnutls_get_pkix(), "PKIX1.Certificate",
          &tmp);
  if (ret != ASN1_SUCCESS) {
    gnutls_assert();
    return _gnutls_asn2err(ret);
  }

  ret = _gnutls_x509_encode_and_copy_PKI_params(
    tmp, "tbsCertificate.subjectPublicKeyInfo", params);
  if (ret != ASN1_SUCCESS) {
    gnutls_assert();
    ret = _gnutls_asn2err(ret);
    goto cleanup;
  }

  ret = _gnutls_x509_der_encode(
    tmp, "tbsCertificate.subjectPublicKeyInfo", der, 0);

cleanup:
  asn1_delete_structure(&tmp);

  return ret;
}

/* Reads and returns the PK algorithm of the given certificate-like
 * ASN.1 structure. src_name should be something like "tbsCertificate.subjectPublicKeyInfo".
 */
int _gnutls_x509_get_pk_algorithm(asn1_node src, const char *src_name,
          gnutls_ecc_curve_t *curve, unsigned int *bits)
{
  int result;
  int algo;
  char oid[64];
  int len;
  gnutls_ecc_curve_t lcurve = GNUTLS_ECC_CURVE_INVALID;
  char name[128];

  _asnstr_append_name(name, sizeof(name), src_name,
          ".algorithm.algorithm");
  len = sizeof(oid);
  result = asn1_read_value(src, name, oid, &len);

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

  algo = _gnutls_oid_to_pk_and_curve(oid, &lcurve);
  if (algo == GNUTLS_PK_UNKNOWN) {
    _gnutls_debug_log("%s: unknown public key algorithm: %s\n",
          __func__, oid);
  }

  if (curve)
    *curve = lcurve;

  if (bits == NULL) {
    return algo;
  }

  /* Now read the parameters' bits
   */
  if (lcurve != GNUTLS_ECC_CURVE_INVALID) { /* curve present */
    bits[0] = gnutls_ecc_curve_get_size(lcurve) * 8;
  } else {
    gnutls_pk_params_st params;
    gnutls_pk_params_init(&params);

    result = _gnutls_get_asn_mpis(src, src_name, &params);
    if (result < 0)
      return gnutls_assert_val(result);

    bits[0] = pubkey_to_bits(&params);
    gnutls_pk_params_release(&params);
  }

  return algo;
}

/* Reads the DER signed data from the certificate and allocates space and
 * returns them into signed_data.
 */
int _gnutls_x509_get_signed_data(asn1_node src, const gnutls_datum_t *der,
         const char *src_name,
         gnutls_datum_t *signed_data)
{
  int start, end, result;

  if (der == NULL || der->size == 0) {
    return _gnutls_x509_der_encode(src, src_name, signed_data, 0);
  }

  /* Get the signed data
   */
  result = asn1_der_decoding_startEnd(src, der->data, der->size, src_name,
              &start, &end);
  if (result != ASN1_SUCCESS) {
    result = _gnutls_asn2err(result);
    gnutls_assert();
    goto cleanup;
  }

  result = _gnutls_set_datum(signed_data, &der->data[start],
           end - start + 1);

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

  result = 0;

cleanup:
  return result;
}

/*-
 * gnutls_x509_get_signature_algorithm:
 * @src: should contain an asn1_node structure
 * @src_name: the description of the signature field
 *
 * This function will return a value of the #gnutls_sign_algorithm_t
 * enumeration that is the signature algorithm that has been used to
 * sign this certificate.
 *
 * Returns: a #gnutls_sign_algorithm_t value, or a negative error code on
 *   error.
 -*/
int _gnutls_x509_get_signature_algorithm(asn1_node src, const char *src_name)
{
  int result;
  char name[128];
  gnutls_datum_t sa = { NULL, 0 };

  _gnutls_str_cpy(name, sizeof(name), src_name);
  _gnutls_str_cat(name, sizeof(name), ".algorithm");

  /* Read the signature algorithm */
  result = _gnutls_x509_read_value(src, name, &sa);

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

  /* Read the signature parameters. Unless the algorithm is
   * RSA-PSS, parameters are not read. They will be read from
   * the issuer's certificate if needed.
   */
  if (sa.data && strcmp((char *)sa.data, PK_PKIX1_RSA_PSS_OID) == 0) {
    gnutls_datum_t der = { NULL, 0 };
    gnutls_x509_spki_st params;

    _gnutls_str_cpy(name, sizeof(name), src_name);
    _gnutls_str_cat(name, sizeof(name), ".parameters");

    result = _gnutls_x509_read_value(src, name, &der);
    if (result < 0) {
      _gnutls_free_datum(&sa);
      return gnutls_assert_val(result);
    }

    result = _gnutls_x509_read_rsa_pss_params(der.data, der.size,
                &params);
    _gnutls_free_datum(&der);

    if (result == 0)
      result = gnutls_pk_to_sign(params.pk,
               params.rsa_pss_dig);
  } else if (sa.data) {
    result = gnutls_oid_to_sign((char *)sa.data);
  } else {
    result = GNUTLS_E_UNKNOWN_ALGORITHM;
  }

  _gnutls_free_datum(&sa);

  if (result == GNUTLS_SIGN_UNKNOWN)
    result = GNUTLS_E_UNKNOWN_ALGORITHM;

  return result;
}

/* Reads the DER signature from the certificate and allocates space and
 * returns them into signed_data.
 */
int _gnutls_x509_get_signature(asn1_node src, const char *src_name,
             gnutls_datum_t *signature)
{
  int result, len;
  int bits;

  signature->data = NULL;
  signature->size = 0;

  /* Read the signature
   */
  len = 0;
  result = asn1_read_value(src, src_name, NULL, &len);

  if (result != ASN1_MEM_ERROR) {
    result = _gnutls_asn2err(result);
    gnutls_assert();
    goto cleanup;
  }

  bits = len;
  if (bits % 8 != 0 || bits < 8) {
    gnutls_assert();
    result = GNUTLS_E_CERTIFICATE_ERROR;
    goto cleanup;
  }

  len = bits / 8;

  signature->data = gnutls_malloc(len);
  if (signature->data == NULL) {
    gnutls_assert();
    result = GNUTLS_E_MEMORY_ERROR;
    return result;
  }

  /* read the bit string of the signature
   */
  bits = len;
  result = asn1_read_value(src, src_name, signature->data, &bits);

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

  signature->size = len;

  return 0;

cleanup:
  gnutls_free(signature->data);
  return result;
}

/* ASN.1 PrintableString rules */
static int is_printable(char p)
{
  if ((p >= 'a' && p <= 'z') || (p >= 'A' && p <= 'Z') ||
      (p >= '0' && p <= '9') || p == ' ' || p == '(' || p == ')' ||
      p == '+' || p == ',' || p == '-' || p == '.' || p == '/' ||
      p == ':' || p == '=' || p == '?')
    return 1;

  return 0;
}

static int write_complex_string(asn1_node asn_struct, const char *where,
        const struct oid_to_string *oentry,
        const uint8_t *data, size_t data_size)
{
  char tmp[128];
  asn1_node c2;
  int result;
  const char *string_type;
  unsigned int i;

  result = asn1_create_element(_gnutls_get_pkix(), oentry->asn_desc, &c2);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    return _gnutls_asn2err(result);
  }

  tmp[0] = 0;

  string_type = "printableString";

  /* Check if the data is ASN.1 printable, and use
   * the UTF8 string type if not.
   */
  for (i = 0; i < data_size; i++) {
    if (!is_printable(data[i])) {
      string_type = "utf8String";
      break;
    }
  }

  /* if the type is a CHOICE then write the
   * type we'll use.
   */
  result = asn1_write_value(c2, "", string_type, 1);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }

  _gnutls_str_cpy(tmp, sizeof(tmp), string_type);

  result = asn1_write_value(c2, tmp, data, data_size);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }

  result = _gnutls_x509_der_encode_and_copy(c2, "", asn_struct, where, 0);
  if (result < 0) {
    gnutls_assert();
    goto error;
  }

  result = 0;

error:
  asn1_delete_structure(&c2);
  return result;
}

/* This will encode and write the AttributeTypeAndValue field.
 * 'multi' must be (0) if writing an AttributeTypeAndValue, and 1 if Attribute.
 * In all cases only one value is written.
 */
int _gnutls_x509_encode_and_write_attribute(const char *given_oid,
              asn1_node asn1_struct,
              const char *where,
              const void *_data, int data_size,
              int multi)
{
  const uint8_t *data = _data;
  char tmp[128];
  int result;
  const struct oid_to_string *oentry;

  oentry = _gnutls_oid_get_entry(_oid2str, given_oid);
  if (oentry == NULL) {
    gnutls_assert();
    _gnutls_debug_log("Cannot find OID: %s\n", given_oid);
    return GNUTLS_E_X509_UNSUPPORTED_OID;
  }

  /* write the data (value)
   */

  _gnutls_str_cpy(tmp, sizeof(tmp), where);
  _gnutls_str_cat(tmp, sizeof(tmp), ".value");

  if (multi !=
      0) { /* if not writing an AttributeTypeAndValue, but an Attribute */
    _gnutls_str_cat(tmp, sizeof(tmp), "s"); /* values */

    result = asn1_write_value(asn1_struct, tmp, "NEW", 1);
    if (result != ASN1_SUCCESS) {
      gnutls_assert();
      result = _gnutls_asn2err(result);
      goto error;
    }

    _gnutls_str_cat(tmp, sizeof(tmp), ".?LAST");
  }

  if (oentry->asn_desc != NULL) { /* write a complex string API */
    result = write_complex_string(asn1_struct, tmp, oentry, data,
                data_size);
    if (result < 0)
      return gnutls_assert_val(result);
  } else { /* write a simple string */

    gnutls_datum_t td;

    td.data = (void *)data;
    td.size = data_size;
    result = _gnutls_x509_write_string(asn1_struct, tmp, &td,
               oentry->etype);
    if (result < 0) {
      gnutls_assert();
      goto error;
    }
  }

  /* write the type
   */
  _gnutls_str_cpy(tmp, sizeof(tmp), where);
  _gnutls_str_cat(tmp, sizeof(tmp), ".type");

  result = asn1_write_value(asn1_struct, tmp, given_oid, 1);
  if (result != ASN1_SUCCESS) {
    gnutls_assert();
    result = _gnutls_asn2err(result);
    goto error;
  }

  result = 0;

error:
  return result;
}

/* copies a datum to a buffer. If it doesn't fit it returns
 * GNUTLS_E_SHORT_MEMORY_BUFFER. It always deinitializes the datum
 * after the copy.
 *
 * The buffer will always be null terminated.
 */
int _gnutls_strdatum_to_buf(gnutls_datum_t *d, void *buf, size_t *buf_size)
{
  int ret;
  uint8_t *_buf = buf;

  if (buf == NULL || *buf_size < d->size + 1) {
    *buf_size = d->size + 1;
    ret = gnutls_assert_val(GNUTLS_E_SHORT_MEMORY_BUFFER);
    goto cleanup;
  }
  memcpy(buf, d->data, d->size);
  _buf[d->size] = 0;

  *buf_size = d->size;
  ret = 0;

cleanup:
  _gnutls_free_datum(d);

  return ret;
}

int _gnutls_x509_get_raw_field2(asn1_node c2, const gnutls_datum_t *raw,
        const char *whom, gnutls_datum_t *dn)
{
  int result, len1;
  int start1, end1;
  result = asn1_der_decoding_startEnd(c2, raw->data, raw->size, whom,
              &start1, &end1);

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

  len1 = end1 - start1 + 1;

  dn->data = &raw->data[start1];
  dn->size = len1;
  result = 0;

cleanup:
  return result;
}

int _gnutls_copy_string(const gnutls_datum_t *str, uint8_t *out,
      size_t *out_size)
{
  unsigned size_to_check;

  size_to_check = str->size + 1;

  if ((unsigned)size_to_check > *out_size) {
    gnutls_assert();
    (*out_size) = size_to_check;
    return GNUTLS_E_SHORT_MEMORY_BUFFER;
  }

  if (out != NULL && str->data != NULL) {
    memcpy(out, str->data, str->size);
    out[str->size] = 0;
  } else if (out != NULL) {
    out[0] = 0;
  }
  *out_size = str->size;

  return 0;
}

int _gnutls_copy_data(const gnutls_datum_t *str, uint8_t *out, size_t *out_size)
{
  if ((unsigned)str->size > *out_size) {
    gnutls_assert();
    (*out_size) = str->size;
    return GNUTLS_E_SHORT_MEMORY_BUFFER;
  }

  if (out != NULL && str->data != NULL) {
    memcpy(out, str->data, str->size);
  }
  *out_size = str->size;

  return 0;
}

/* Converts an X.509 certificate to subjectPublicKeyInfo */
int x509_crt_to_raw_pubkey(gnutls_x509_crt_t crt, gnutls_datum_t *rpubkey)
{
  gnutls_pubkey_t pubkey = NULL;
  int ret;

  ret = gnutls_pubkey_init(&pubkey);
  if (ret < 0)
    return gnutls_assert_val(ret);

  ret = gnutls_pubkey_import_x509(pubkey, crt, 0);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  ret = gnutls_pubkey_export2(pubkey, GNUTLS_X509_FMT_DER, rpubkey);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  ret = 0;

cleanup:
  gnutls_pubkey_deinit(pubkey);
  return ret;
}

/* Converts an X.509 certificate to subjectPublicKeyInfo */
int _gnutls_x509_raw_crt_to_raw_pubkey(const gnutls_datum_t *cert,
               gnutls_datum_t *rpubkey)
{
  gnutls_x509_crt_t crt = NULL;
  int ret;

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

  ret = gnutls_x509_crt_import(crt, cert, GNUTLS_X509_FMT_DER);
  if (ret < 0) {
    gnutls_assert();
    goto cleanup;
  }

  ret = x509_crt_to_raw_pubkey(crt, rpubkey);
cleanup:
  gnutls_x509_crt_deinit(crt);

  return ret;
}

unsigned _gnutls_check_valid_key_id(const gnutls_datum_t *key_id,
            gnutls_x509_crt_t cert, time_t now,
            unsigned *has_ski)
{
  uint8_t id[MAX_KEY_ID_SIZE];
  size_t id_size;
  unsigned result = 0;

  if (has_ski)
    *has_ski = 0;

  if (now > gnutls_x509_crt_get_expiration_time(cert) ||
      now < gnutls_x509_crt_get_activation_time(cert)) {
    /* don't bother, certificate is not yet activated or expired */
    gnutls_assert();
    goto out;
  }

  id_size = sizeof(id);
  if (gnutls_x509_crt_get_subject_key_id(cert, id, &id_size, NULL) < 0) {
    gnutls_assert();
    goto out;
  }

  if (has_ski)
    *has_ski = 1;

  if (id_size == key_id->size && !memcmp(id, key_id->data, id_size))
    result = 1;

out:
  return result;
}

/* Sort a certificate list in place with subject, issuer order. @clist_size must
 * be equal to or less than %DEFAULT_MAX_VERIFY_DEPTH.
 *
 * Returns the index in clist where the initial contiguous segment ends. If the
 * chain contains multiple segments separated by gaps (e.g., missing issuers),
 * the caller shall call this function multiple times.
 *
 * For example, suppose we want the following certificate chain as a result of
 * sorting:
 *
 *   A -> (B) -> C -> D -> E -> (F) -> G -> H -> I
 *
 * from the input [A, C, E, D, G, I, H] (B and F are missing).
 *
 * On the first call of this function:
 *
 *   _gnutls_sort_clist(clist, clist_size)
 *
 * it returns 1, meaning that the first segment only contains A.  The content of
 * @clist will remain the same [A, C, E, D, G, I, H].
 *
 * Then the caller will call this function again, starting from the second
 * element:
 *
 *   _gnutls_sort_clist(&clist[1], clist_size - 1)
 *
 * This time it returns 3, meaning that the first segment contains [C, D, E].
 * The content of @clist will be [A, C, D, E, G, I, H].
 *
 * Finally, after calling the function on the remaining elements:
 *
 *   _gnutls_sort_clist(&clist[1 + 3], clist_size - (1 + 3))
 *
 * It will return 3, meaning that the first segment contains [G, H, I].  At this
 * point, sorting of @clist is complete.
 */
unsigned int _gnutls_sort_clist(gnutls_x509_crt_t *clist,
        unsigned int clist_size)
{
  int prev;
  unsigned int i, j, k;
  int issuer[DEFAULT_MAX_VERIFY_DEPTH]; /* contain the index of the issuers */
  bool insorted[DEFAULT_MAX_VERIFY_DEPTH]; /* non zero if clist[i] used in sorted list */
  gnutls_x509_crt_t sorted[DEFAULT_MAX_VERIFY_DEPTH];

  /* Limit the number of certificates in the chain, to avoid DoS
   * because of the O(n^2) sorting below.  FIXME: Switch to a
   * topological sort algorithm which should be linear to the
   * number of certificates and subject-issuer relationships.
   */
  if (clist_size > DEFAULT_MAX_VERIFY_DEPTH) {
    _gnutls_debug_log("too many certificates; skipping sorting\n");
    return 1;
  }

  for (i = 0; i < DEFAULT_MAX_VERIFY_DEPTH; i++) {
    issuer[i] = -1;
    insorted[i] = 0;
  }

  /* Find the issuer of each certificate and store it
   * in issuer array. O(n^2) so consider that before
   * increasing DEFAULT_MAX_VERIFY_DEPTH.
   */
  for (i = 0; i < clist_size; i++) {
    /* Self-signed certificate found in the chain; skip it
     * as it should only appear in the trusted set.
     */
    if (gnutls_x509_crt_check_issuer(clist[i], clist[i])) {
      _gnutls_cert_log("self-signed cert found", clist[i]);
      continue;
    }

    for (j = 1; j < clist_size; j++) {
      if (i == j)
        continue;

      if (gnutls_x509_crt_check_issuer(clist[i], clist[j])) {
        issuer[i] = j;
        break;
      }
    }
  }

  sorted[0] = clist[0];
  insorted[0] = 1;

  prev = 0;
  for (i = 1; i < clist_size; i++) {
    prev = issuer[prev];
    if (prev < 0) { /* no issuer */
      break;
    }

    if (insorted[prev]) { /* loop detected */
      break;
    }

    sorted[i] = clist[prev];
    insorted[prev] = 1;
  }

  /* append the remaining certs */
  for (j = 1, k = i; j < clist_size; j++) {
    if (!insorted[j]) {
      sorted[k++] = clist[j];
    }
  }

  /* write out the sorted list */
  assert(k == clist_size);
  for (j = 0; j < clist_size; j++) {
    clist[j] = sorted[j];
  }

  return i;
}

int _gnutls_check_if_sorted(gnutls_x509_crt_t *crt, int nr)
{
  int i, ret;

  /* check if the X.509 list is ordered */
  if (nr > 1) {
    for (i = 0; i < nr; i++) {
      if (i > 0) {
        if (!_gnutls_x509_compare_raw_dn(
              &crt[i]->raw_dn,
              &crt[i - 1]->raw_issuer_dn)) {
          ret = gnutls_assert_val(
            GNUTLS_E_CERTIFICATE_LIST_UNSORTED);
          goto cleanup;
        }
      }
    }
  }
  ret = 0;

cleanup:
  return ret;
}

/**
 * gnutls_gost_paramset_get_name:
 * @param: is a GOST 28147 param set
 *
 * Convert a #gnutls_gost_paramset_t value to a string.
 *
 * Returns: a string that contains the name of the specified GOST param set,
 *   or %NULL.
 *
 * Since: 3.6.3
 **/
const char *gnutls_gost_paramset_get_name(gnutls_gost_paramset_t param)
{
  switch (param) {
  case GNUTLS_GOST_PARAMSET_TC26_Z:
    return "TC26-Z";
  case GNUTLS_GOST_PARAMSET_CP_A:
    return "CryptoPro-A";
  case GNUTLS_GOST_PARAMSET_CP_B:
    return "CryptoPro-B";
  case GNUTLS_GOST_PARAMSET_CP_C:
    return "CryptoPro-C";
  case GNUTLS_GOST_PARAMSET_CP_D:
    return "CryptoPro-D";
  default:
    gnutls_assert();
    return "Unknown";
  }
}

/**
 * gnutls_gost_paramset_get_oid:
 * @param: is a GOST 28147 param set
 *
 * Convert a #gnutls_gost_paramset_t value to its object identifier.
 *
 * Returns: a string that contains the object identifier of the specified GOST
 *   param set, or %NULL.
 *
 * Since: 3.6.3
 **/
const char *gnutls_gost_paramset_get_oid(gnutls_gost_paramset_t param)
{
  switch (param) {
  case GNUTLS_GOST_PARAMSET_TC26_Z:
    return GOST28147_89_TC26Z_OID;
  case GNUTLS_GOST_PARAMSET_CP_A:
    return GOST28147_89_CPA_OID;
  case GNUTLS_GOST_PARAMSET_CP_B:
    return GOST28147_89_CPB_OID;
  case GNUTLS_GOST_PARAMSET_CP_C:
    return GOST28147_89_CPC_OID;
  case GNUTLS_GOST_PARAMSET_CP_D:
    return GOST28147_89_CPD_OID;
  default:
    gnutls_assert();
    return NULL;
  }
}

/**
 * gnutls_oid_to_gost_paramset:
 * @oid: is an object identifier
 *
 * Converts a textual object identifier to a #gnutls_gost_paramset_t value.
 *
 * Returns: a #gnutls_gost_paramset_get_oid of the specified GOST 28147
 *   param st, or %GNUTLS_GOST_PARAMSET_UNKNOWN on failure.
 *
 * Since: 3.6.3
 **/
gnutls_gost_paramset_t gnutls_oid_to_gost_paramset(const char *oid)
{
  if (!strcmp(oid, GOST28147_89_TC26Z_OID))
    return GNUTLS_GOST_PARAMSET_TC26_Z;
  else if (!strcmp(oid, GOST28147_89_CPA_OID))
    return GNUTLS_GOST_PARAMSET_CP_A;
  else if (!strcmp(oid, GOST28147_89_CPB_OID))
    return GNUTLS_GOST_PARAMSET_CP_B;
  else if (!strcmp(oid, GOST28147_89_CPC_OID))
    return GNUTLS_GOST_PARAMSET_CP_C;
  else if (!strcmp(oid, GOST28147_89_CPD_OID))
    return GNUTLS_GOST_PARAMSET_CP_D;
  else
    return gnutls_assert_val(GNUTLS_GOST_PARAMSET_UNKNOWN);
}

int _gnutls_x509_get_version(asn1_node root, const char *name)
{
  uint8_t version[8];
  int len, result;

  len = sizeof(version);
  result = asn1_read_value(root, name, version, &len);
  if (result != ASN1_SUCCESS) {
    if (result == ASN1_ELEMENT_NOT_FOUND)
      return 1; /* the DEFAULT version */
    gnutls_assert();
    return _gnutls_asn2err(result);
  }

  if (len != 1 || version[0] >= 0x80)
    return gnutls_assert_val(GNUTLS_E_ASN1_DER_ERROR);

  return (int)version[0] + 1;
}

Coverage Report

Created: 2026-02-14 07:17