/*

 * Copyright (C) 2003-2014 Free Software Foundation, Inc.

 *

 * Author: Nikos Mavrogiannopoulos

 *

 * This file is part of GnuTLS.

 *

 * The GnuTLS is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public License

 * as published by the Free Software Foundation; either version 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 to the X.509 extension parsing.

 */

#include "gnutls_int.h"

#include "errors.h"

#include "global.h"

#include <libtasn1.h>

#include "common.h"

#include <gnutls/x509-ext.h>

#include <gnutls/x509.h>

#include "x509_int.h"

#include "datum.h"

int _gnutls_get_extension(asn1_node asn, const char *root,

        const char *extension_id, int indx,

        gnutls_datum_t *ret, unsigned int *_critical)

{

  int k, result, len;

  char name[MAX_NAME_SIZE], name2[MAX_NAME_SIZE];

  char str_critical[10];

  int critical = 0;

  char extnID[MAX_OID_SIZE];

  gnutls_datum_t value;

  int indx_counter = 0;

  ret->data = NULL;

  ret->size = 0;

  k = 0;

  do {

    k++;

    snprintf(name, sizeof(name), "%s.?%d", root, k);

    _gnutls_str_cpy(name2, sizeof(name2), name);

    _gnutls_str_cat(name2, sizeof(name2), ".extnID");

    len = sizeof(extnID) - 1;

    result = asn1_read_value(asn, name2, extnID, &len);

    if (result == ASN1_ELEMENT_NOT_FOUND) {

      break;

    } else if (result != ASN1_SUCCESS) {

      gnutls_assert();

      return _gnutls_asn2err(result);

    }

    /* Handle Extension 

     */

    if (streq(extnID, extension_id) && indx == indx_counter++) {

      /* extension was found 

       */

      /* read the critical status.

       */

      _gnutls_str_cpy(name2, sizeof(name2), name);

      _gnutls_str_cat(name2, sizeof(name2), ".critical");

      len = sizeof(str_critical);

      result =

        asn1_read_value(asn, name2, str_critical, &len);

      if (result == ASN1_ELEMENT_NOT_FOUND) {

        gnutls_assert();

        break;

      } else if (result != ASN1_SUCCESS) {

        gnutls_assert();

        return _gnutls_asn2err(result);

      }

      if (str_critical[0] == 'T')

        critical = 1;

      else

        critical = 0;

      /* read the value.

       */

      _gnutls_str_cpy(name2, sizeof(name2), name);

      _gnutls_str_cat(name2, sizeof(name2), ".extnValue");

      result = _gnutls_x509_read_value(asn, name2, &value);

      if (result < 0) {

        gnutls_assert();

        return result;

      }

      ret->data = value.data;

      ret->size = value.size;

      if (_critical)

        *_critical = critical;

      return 0;

    }

  } while (1);

  if (result == ASN1_ELEMENT_NOT_FOUND) {

    return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;

  } else {

    gnutls_assert();

    return _gnutls_asn2err(result);

  }

}

static int get_indx_extension(asn1_node asn, const char *root, int indx,

            gnutls_datum_t *out)

{

  char name[MAX_NAME_SIZE];

  int ret;

  out->data = NULL;

  out->size = 0;

  snprintf(name, sizeof(name), "%s.?%d.extnValue", root, indx + 1);

  ret = _gnutls_x509_read_value(asn, name, out);

  if (ret < 0)

    return gnutls_assert_val(ret);

  return 0;

}

int _gnutls_x509_crt_get_extension(gnutls_x509_crt_t cert,

           const char *extension_id, int indx,

           gnutls_datum_t *data, unsigned int *critical)

{

  return _gnutls_get_extension(cert->cert, "tbsCertificate.extensions",

             extension_id, indx, data, critical);

}

/**

 * gnutls_x509_crt_get_extension_data2:

 * @cert: should contain a #gnutls_x509_crt_t type

 * @indx: Specifies which extension OID to read. Use (0) to get the first one.

 * @data: will contain the extension DER-encoded data

 *

 * This function will return the requested by the index extension data in the

 * certificate.  The extension data will be allocated using

 * gnutls_malloc().

 *

 * Use gnutls_x509_crt_get_extension_info() to extract the OID.

 *

 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned,

 *   otherwise a negative error code is returned.  If you have reached the

 *   last extension available %GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE

 *   will be returned.

 **/

int gnutls_x509_crt_get_extension_data2(gnutls_x509_crt_t cert, unsigned indx,

          gnutls_datum_t *data)

{

  return get_indx_extension(cert->cert, "tbsCertificate.extensions", indx,

          data);

}

int _gnutls_x509_crl_get_extension(gnutls_x509_crl_t crl,

           const char *extension_id, int indx,

           gnutls_datum_t *data, unsigned int *critical)

{

  return _gnutls_get_extension(crl->crl, "tbsCertList.crlExtensions",

             extension_id, indx, data, critical);

}

/**

 * gnutls_x509_crl_get_extension_data2:

 * @crl: should contain a #gnutls_x509_crl_t type

 * @indx: Specifies which extension OID to read. Use (0) to get the first one.

 * @data: will contain the extension DER-encoded data

 *

 * This function will return the requested by the index extension data in the

 * certificate revocation list.  The extension data will be allocated using

 * gnutls_malloc().

 *

 * Use gnutls_x509_crt_get_extension_info() to extract the OID.

 *

 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned,

 *   otherwise a negative error code is returned.  If you have reached the

 *   last extension available %GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE

 *   will be returned.

 **/

int gnutls_x509_crl_get_extension_data2(gnutls_x509_crl_t crl, unsigned indx,

          gnutls_datum_t *data)

{

  return get_indx_extension(crl->crl, "tbsCertList.crlExtensions", indx,

          data);

}

/* This function will attempt to return the requested extension OID found in

 * the given X509v3 certificate. 

 *

 * If you have passed the last extension, GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will

 * be returned.

 */

static int get_extension_oid(asn1_node asn, const char *root, unsigned indx,

           void *oid, size_t *sizeof_oid)

{

  int k, result, len;

  char name[MAX_NAME_SIZE], name2[MAX_NAME_SIZE];

  char extnID[MAX_OID_SIZE];

  unsigned indx_counter = 0;

  k = 0;

  do {

    k++;

    snprintf(name, sizeof(name), "%s.?%d", root, k);

    _gnutls_str_cpy(name2, sizeof(name2), name);

    _gnutls_str_cat(name2, sizeof(name2), ".extnID");

    len = sizeof(extnID) - 1;

    result = asn1_read_value(asn, name2, extnID, &len);

    if (result == ASN1_ELEMENT_NOT_FOUND) {

      gnutls_assert();

      break;

    } else if (result != ASN1_SUCCESS) {

      gnutls_assert();

      return _gnutls_asn2err(result);

    }

    /* Handle Extension 

     */

    if (indx == indx_counter++) {

      len = strlen(extnID) + 1;

      if (*sizeof_oid < (unsigned)len) {

        *sizeof_oid = len;

        gnutls_assert();

        return GNUTLS_E_SHORT_MEMORY_BUFFER;

      }

      memcpy(oid, extnID, len);

      *sizeof_oid = len - 1;

      return 0;

    }

  } while (1);

  if (result == ASN1_ELEMENT_NOT_FOUND) {

    return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;

  } else {

    gnutls_assert();

    return _gnutls_asn2err(result);

  }

}

/* This function will attempt to return the requested extension OID found in

 * the given X509v3 certificate. 

 *

 * If you have passed the last extension, GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will

 * be returned.

 */

int _gnutls_x509_crt_get_extension_oid(gnutls_x509_crt_t cert, int indx,

               void *oid, size_t *sizeof_oid)

{

  return get_extension_oid(cert->cert, "tbsCertificate.extensions", indx,

         oid, sizeof_oid);

}

int _gnutls_x509_crl_get_extension_oid(gnutls_x509_crl_t crl, int indx,

               void *oid, size_t *sizeof_oid)

{

  return get_extension_oid(crl->crl, "tbsCertList.crlExtensions", indx,

         oid, sizeof_oid);

}

/* This function will attempt to set the requested extension in

 * the given X509v3 certificate. 

 *

 * Critical will be either 0 or 1.

 */

static int add_extension(asn1_node asn, const char *root,

       const char *extension_id,

       const gnutls_datum_t *ext_data, unsigned int critical)

{

  int result;

  const char *str;

  char name[MAX_NAME_SIZE];

  snprintf(name, sizeof(name), "%s", root);

  /* Add a new extension in the list.

   */

  result = asn1_write_value(asn, name, "NEW", 1);

  if (result != ASN1_SUCCESS) {

    gnutls_assert();

    return _gnutls_asn2err(result);

  }

  if (root[0] != 0)

    snprintf(name, sizeof(name), "%s.?LAST.extnID", root);

  else

    snprintf(name, sizeof(name), "?LAST.extnID");

  result = asn1_write_value(asn, name, extension_id, 1);

  if (result != ASN1_SUCCESS) {

    gnutls_assert();

    return _gnutls_asn2err(result);

  }

  if (critical == 0)

    str = "FALSE";

  else

    str = "TRUE";

  if (root[0] != 0)

    snprintf(name, sizeof(name), "%s.?LAST.critical", root);

  else

    snprintf(name, sizeof(name), "?LAST.critical");

  result = asn1_write_value(asn, name, str, 1);

  if (result != ASN1_SUCCESS) {

    gnutls_assert();

    return _gnutls_asn2err(result);

  }

  if (root[0] != 0)

    snprintf(name, sizeof(name), "%s.?LAST.extnValue", root);

  else

    snprintf(name, sizeof(name), "?LAST.extnValue");

  result = _gnutls_x509_write_value(asn, name, ext_data);

  if (result < 0) {

    gnutls_assert();

    return result;

  }

  return 0;

}

/* Overwrite the given extension (using the index)

 * index here starts from one.

 */

static int overwrite_extension(asn1_node asn, const char *root,

             unsigned int indx,

             const gnutls_datum_t *ext_data,

             unsigned int critical)

{

  char name[MAX_NAME_SIZE], name2[MAX_NAME_SIZE];

  const char *str;

  int result;

  if (root[0] != 0)

    snprintf(name, sizeof(name), "%s.?%u", root, indx);

  else

    snprintf(name, sizeof(name), "?%u", indx);

  if (critical == 0)

    str = "FALSE";

  else

    str = "TRUE";

  _gnutls_str_cpy(name2, sizeof(name2), name);

  _gnutls_str_cat(name2, sizeof(name2), ".critical");

  result = asn1_write_value(asn, name2, str, 1);

  if (result != ASN1_SUCCESS) {

    gnutls_assert();

    return _gnutls_asn2err(result);

  }

  _gnutls_str_cpy(name2, sizeof(name2), name);

  _gnutls_str_cat(name2, sizeof(name2), ".extnValue");

  result = _gnutls_x509_write_value(asn, name2, ext_data);

  if (result < 0) {

    gnutls_assert();

    return result;

  }

  return 0;

}

int _gnutls_set_extension(asn1_node asn, const char *root, const char *ext_id,

        const gnutls_datum_t *ext_data, unsigned int critical)

{

  int result = 0;

  int k, len;

  char name[MAX_NAME_SIZE], name2[MAX_NAME_SIZE];

  char extnID[MAX_OID_SIZE];

  /* Find the index of the given extension.

   */

  k = 0;

  do {

    k++;

    if (root[0] != 0)

      snprintf(name, sizeof(name), "%s.?%d", root, k);

    else

      snprintf(name, sizeof(name), "?%d", k);

    len = sizeof(extnID) - 1;

    result = asn1_read_value(asn, name, extnID, &len);

    /* move to next

     */

    if (result == ASN1_ELEMENT_NOT_FOUND) {

      break;

    }

    do {

      _gnutls_str_cpy(name2, sizeof(name2), name);

      _gnutls_str_cat(name2, sizeof(name2), ".extnID");

      len = sizeof(extnID) - 1;

      result = asn1_read_value(asn, name2, extnID, &len);

      if (result == ASN1_ELEMENT_NOT_FOUND) {

        gnutls_assert();

        break;

      } else if (result != ASN1_SUCCESS) {

        gnutls_assert();

        return _gnutls_asn2err(result);

      }

      /* Handle Extension 

       */

      if (streq(extnID, ext_id)) {

        /* extension was found 

         */

        return overwrite_extension(asn, root, k,

                 ext_data, critical);

      }

    } while (0);

  } while (1);

  if (result == ASN1_ELEMENT_NOT_FOUND) {

    return add_extension(asn, root, ext_id, ext_data, critical);

  } else {

    gnutls_assert();

    return _gnutls_asn2err(result);

  }

  return 0;

}

/* This function will attempt to overwrite the requested extension with

 * the given one. 

 *

 * Critical will be either 0 or 1.

 */

int _gnutls_x509_crt_set_extension(gnutls_x509_crt_t cert, const char *ext_id,

           const gnutls_datum_t *ext_data,

           unsigned int critical)

{

  MODIFIED(cert);

  cert->use_extensions = 1;

  return _gnutls_set_extension(cert->cert, "tbsCertificate.extensions",

             ext_id, ext_data, critical);

}

int _gnutls_x509_crl_set_extension(gnutls_x509_crl_t crl, const char *ext_id,

           const gnutls_datum_t *ext_data,

           unsigned int critical)

{

  return _gnutls_set_extension(crl->crl, "tbsCertList.crlExtensions",

             ext_id, ext_data, critical);

}

int _gnutls_x509_crq_set_extension(gnutls_x509_crq_t crq, const char *ext_id,

           const gnutls_datum_t *ext_data,

           unsigned int critical)

{

  unsigned char *extensions = NULL;

  size_t extensions_size = 0;

  gnutls_datum_t der;

  asn1_node c2;

  int result;

  result = gnutls_x509_crq_get_attribute_by_oid(

    crq, "1.2.840.113549.1.9.14", 0, NULL, &extensions_size);

  if (result == GNUTLS_E_SHORT_MEMORY_BUFFER) {

    extensions = gnutls_malloc(extensions_size);

    if (extensions == NULL) {

      gnutls_assert();

      return GNUTLS_E_MEMORY_ERROR;

    }

    result = gnutls_x509_crq_get_attribute_by_oid(

      crq, "1.2.840.113549.1.9.14", 0, extensions,

      &extensions_size);

  }

  if (result < 0) {

    if (result == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) {

      extensions_size = 0;

    } else {

      gnutls_assert();

      gnutls_free(extensions);

      return result;

    }

  }

  result = asn1_create_element(_gnutls_get_pkix(), "PKIX1.Extensions",

             &c2);

  if (result != ASN1_SUCCESS) {

    gnutls_assert();

    gnutls_free(extensions);

    return _gnutls_asn2err(result);

  }

  if (extensions_size > 0) {

    result = _asn1_strict_der_decode(&c2, extensions,

             extensions_size, NULL);

    gnutls_free(extensions);

    if (result != ASN1_SUCCESS) {

      gnutls_assert();

      asn1_delete_structure(&c2);

      return _gnutls_asn2err(result);

    }

  }

  result = _gnutls_set_extension(c2, "", ext_id, ext_data, critical);

  if (result < 0) {

    gnutls_assert();

    asn1_delete_structure(&c2);

    return result;

  }

  result = _gnutls_x509_der_encode(c2, "", &der, 0);

  asn1_delete_structure(&c2);

  if (result < 0) {

    gnutls_assert();

    return result;

  }

  result = gnutls_x509_crq_set_attribute_by_oid(

    crq, "1.2.840.113549.1.9.14", der.data, der.size);

  gnutls_free(der.data);

  if (result < 0) {

    gnutls_assert();

    return result;

  }

  return 0;

}

/* extract an INTEGER from the DER encoded extension

 */

int _gnutls_x509_ext_extract_number(uint8_t *number, size_t *_nr_size,

            uint8_t *extnValue, int extnValueLen)

{

  asn1_node ext = NULL;

  int result;

  int nr_size = *_nr_size;

  /* here it doesn't matter so much that we use CertificateSerialNumber. It is equal

   * to using INTEGER.

   */

  if ((result = asn1_create_element(_gnutls_get_pkix(),

            "PKIX1.CertificateSerialNumber",

            &ext)) != ASN1_SUCCESS) {

    gnutls_assert();

    return _gnutls_asn2err(result);

  }

  result = _asn1_strict_der_decode(&ext, extnValue, extnValueLen, NULL);

  if (result != ASN1_SUCCESS) {

    gnutls_assert();

    asn1_delete_structure(&ext);

    return _gnutls_asn2err(result);

  }

  /* the default value of cA is false.

   */

  result = asn1_read_value(ext, "", number, &nr_size);

  if (result != ASN1_SUCCESS)

    result = _gnutls_asn2err(result);

  else

    result = 0;

  *_nr_size = nr_size;

  asn1_delete_structure(&ext);

  return result;

}

/* generate an INTEGER in a DER encoded extension

 */

int _gnutls_x509_ext_gen_number(const uint8_t *number, size_t nr_size,

        gnutls_datum_t *der_ext)

{

  asn1_node ext = NULL;

  int result;

  result = asn1_create_element(_gnutls_get_pkix(),

             "PKIX1.CertificateSerialNumber", &ext);

  if (result != ASN1_SUCCESS) {

    gnutls_assert();

    return _gnutls_asn2err(result);

  }

  result = asn1_write_value(ext, "", number, nr_size);

  if (result != ASN1_SUCCESS) {

    gnutls_assert();

    asn1_delete_structure(&ext);

    return _gnutls_asn2err(result);

  }

  result = _gnutls_x509_der_encode(ext, "", der_ext, 0);

  asn1_delete_structure(&ext);

  if (result < 0) {

    gnutls_assert();

    return result;

  }

  return 0;

}

int _gnutls_write_general_name(asn1_node ext, const char *ext_name,

             gnutls_x509_subject_alt_name_t type,

             const void *data, unsigned int data_size)

{

  const char *str;

  int result;

  char name[128];

  if (data == NULL) {

    if (data_size == 0)

      data = (void *)"";

    else

      return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

  }

  switch (type) {

  case GNUTLS_SAN_DNSNAME:

    str = "dNSName";

    break;

  case GNUTLS_SAN_RFC822NAME:

    str = "rfc822Name";

    break;

  case GNUTLS_SAN_URI:

    str = "uniformResourceIdentifier";

    break;

  case GNUTLS_SAN_IPADDRESS:

    str = "iPAddress";

    break;

  case GNUTLS_SAN_REGISTERED_ID:

    str = "registeredID";

    break;

  default:

    gnutls_assert();

    return GNUTLS_E_INTERNAL_ERROR;

  }

  result = asn1_write_value(ext, ext_name, str, 1);

  if (result != ASN1_SUCCESS) {

    gnutls_assert();

    return _gnutls_asn2err(result);

  }

  snprintf(name, sizeof(name), "%s.%s", ext_name, str);

  result = asn1_write_value(ext, name, data, data_size);

  if (result != ASN1_SUCCESS) {

    gnutls_assert();

    asn1_delete_structure(&ext);

    return _gnutls_asn2err(result);

  }

  return 0;

}

int _gnutls_write_new_general_name(asn1_node ext, const char *ext_name,

           gnutls_x509_subject_alt_name_t type,

           const void *data, unsigned int data_size)

{

  int result;

  char name[128];

  result = asn1_write_value(ext, ext_name, "NEW", 1);

  if (result != ASN1_SUCCESS) {

    gnutls_assert();

    return _gnutls_asn2err(result);

  }

  if (ext_name[0] == 0) { /* no dot */

    _gnutls_str_cpy(name, sizeof(name), "?LAST");

  } else {

    _gnutls_str_cpy(name, sizeof(name), ext_name);

    _gnutls_str_cat(name, sizeof(name), ".?LAST");

  }

  result = _gnutls_write_general_name(ext, name, type, data, data_size);

  if (result < 0) {

    gnutls_assert();

    return result;

  }

  return 0;

}

int _gnutls_write_new_othername(asn1_node ext, const char *ext_name,

        const char *oid, const void *data,

        unsigned int data_size)

{

  int result;

  char name[128];

  char name2[128];

  result = asn1_write_value(ext, ext_name, "NEW", 1);

  if (result != ASN1_SUCCESS) {

    gnutls_assert();

    return _gnutls_asn2err(result);

  }

  if (ext_name[0] == 0) { /* no dot */

    _gnutls_str_cpy(name, sizeof(name), "?LAST");

  } else {

    _gnutls_str_cpy(name, sizeof(name), ext_name);

    _gnutls_str_cat(name, sizeof(name), ".?LAST");

  }

  result = asn1_write_value(ext, name, "otherName", 1);

  if (result != ASN1_SUCCESS) {

    gnutls_assert();

    return _gnutls_asn2err(result);

  }

  snprintf(name2, sizeof(name2), "%s.otherName.type-id", name);

  result = asn1_write_value(ext, name2, oid, 1);

  if (result != ASN1_SUCCESS) {

    gnutls_assert();

    return _gnutls_asn2err(result);

  }

  snprintf(name2, sizeof(name2), "%s.otherName.value", name);

  result = asn1_write_value(ext, name2, data, data_size);

  if (result != ASN1_SUCCESS) {

    gnutls_assert();

    return _gnutls_asn2err(result);

  }

  return 0;

}

/* Convert the given name to GeneralNames in a DER encoded extension.

 * This is the same as subject alternative name.

 */

int _gnutls_x509_ext_gen_subject_alt_name(gnutls_x509_subject_alt_name_t type,

            const char *othername_oid,

            const void *data,

            unsigned int data_size,

            const gnutls_datum_t *prev_der_ext,

            gnutls_datum_t *der_ext)

{

  int ret;

  gnutls_subject_alt_names_t sans = NULL;

  gnutls_datum_t name;

  ret = gnutls_subject_alt_names_init(&sans);

  if (ret < 0) {

    gnutls_assert();

    return ret;

  }

  if (prev_der_ext && prev_der_ext->data != NULL &&

      prev_der_ext->size != 0) {

    ret = gnutls_x509_ext_import_subject_alt_names(prev_der_ext,

                     sans, 0);

    if (ret < 0) {

      gnutls_assert();

      goto cleanup;

    }

  }

  name.data = (void *)data;

  name.size = data_size;

  ret = gnutls_subject_alt_names_set(sans, type, &name, othername_oid);

  if (ret < 0) {

    gnutls_assert();

    goto cleanup;

  }

  ret = gnutls_x509_ext_export_subject_alt_names(sans, der_ext);

  if (ret < 0) {

    gnutls_assert();

    goto cleanup;

  }

  ret = 0;

cleanup:

  if (sans != NULL)

    gnutls_subject_alt_names_deinit(sans);

  return ret;

}

/* generate the AuthorityKeyID in a DER encoded extension

 */

int _gnutls_x509_ext_gen_auth_key_id(const void *id, size_t id_size,

             gnutls_datum_t *der_ext)

{

  gnutls_x509_aki_t aki;

  int ret;

  gnutls_datum_t l_id;

  ret = gnutls_x509_aki_init(&aki);

  if (ret < 0)

    return gnutls_assert_val(ret);

  l_id.data = (void *)id;

  l_id.size = id_size;

  ret = gnutls_x509_aki_set_id(aki, &l_id);

  if (ret < 0) {

    gnutls_assert();

    goto cleanup;

  }

  ret = gnutls_x509_ext_export_authority_key_id(aki, der_ext);

  if (ret < 0) {

    gnutls_assert();

    goto cleanup;

  }

  ret = 0;

cleanup:

  gnutls_x509_aki_deinit(aki);

  return ret;

}