/*

 * Copyright (C) 2017 Tim Rühsen

 * Copyright (C) 2016, 2017 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 "errors.h"

#include "str.h"

#include <unistr.h>

#ifdef HAVE_LIBIDN2

#include <idn2.h>

#define ICAST char

/**

 * gnutls_idna_map:

 * @input: contain the UTF-8 formatted domain name

 * @ilen: the length of the provided string

 * @out: the result in an null-terminated allocated string

 * @flags: should be zero

 *

 * This function will convert the provided UTF-8 domain name, to

 * its IDNA mapping in an allocated variable. Note that depending on the flags the used gnutls

 * library was compiled with, the output of this function may vary (i.e.,

 * may be IDNA2008, or IDNA2003).

 *

 * To force IDNA2008 specify the flag %GNUTLS_IDNA_FORCE_2008. In

 * the case GnuTLS is not compiled with the necessary dependencies,

 * %GNUTLS_E_UNIMPLEMENTED_FEATURE will be returned to indicate that

 * gnutls is unable to perform the requested conversion.

 *

 * Note also, that this function will return an empty string if an

 * empty string is provided as input.

 *

 * Returns: %GNUTLS_E_INVALID_UTF8_STRING on invalid UTF-8 data, or 0 on success.

 *

 * Since: 3.5.8

 **/

int gnutls_idna_map(const char *input, unsigned ilen, gnutls_datum_t *out,

        unsigned flags)

{

  char *idna = NULL;

  int rc, ret;

  gnutls_datum_t istr;

  unsigned int idn2_flags = IDN2_NFC_INPUT;

  unsigned int idn2_tflags = IDN2_NFC_INPUT;

  /* IDN2_NONTRANSITIONAL automatically converts to lowercase

   * IDN2_NFC_INPUT converts to NFC before toASCII conversion

   *

   * Since IDN2_NONTRANSITIONAL implicitly does NFC conversion, we don't need

   * the additional IDN2_NFC_INPUT. But just for the unlikely case that the linked

   * library is not matching the headers when building and it doesn't support TR46,

   * we provide IDN2_NFC_INPUT.

   *

   * Without IDN2_USE_STD3_ASCII_RULES, the result could contain any ASCII characters,

   * e.g. 'evil.c\u2100.example.com' will be converted into

   * 'evil.ca/c.example.com', which seems no good idea. */

  idn2_flags |= IDN2_NONTRANSITIONAL | IDN2_USE_STD3_ASCII_RULES;

  idn2_tflags |= IDN2_TRANSITIONAL | IDN2_USE_STD3_ASCII_RULES;

  if (ilen == 0) {

    out->data = (uint8_t *)gnutls_strdup("");

    out->size = 0;

    if (out->data == NULL)

      return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);

    return 0;

  }

  if (_gnutls_str_is_print(input, ilen)) {

    return _gnutls_set_strdatum(out, input, ilen);

  }

  ret = _gnutls_set_strdatum(&istr, input, ilen);

  if (ret < 0) {

    gnutls_assert();

    return ret;

  }

  rc = idn2_to_ascii_8z((ICAST *)istr.data, (ICAST **)&idna, idn2_flags);

  if (rc == IDN2_DISALLOWED && !(flags & GNUTLS_IDNA_FORCE_2008))

    rc = idn2_to_ascii_8z((ICAST *)istr.data, (ICAST **)&idna,

              idn2_tflags);

  if (rc != IDN2_OK) {

    gnutls_assert();

    idna = NULL; /* in case idn2_lookup_u8 modifies &idna */

    _gnutls_debug_log(

      "unable to convert name '%s' to IDNA format: %s\n",

      istr.data, idn2_strerror(rc));

    ret = GNUTLS_E_INVALID_UTF8_STRING;

    goto fail;

  }

  if (gnutls_free != idn2_free) {

    ret = _gnutls_set_strdatum(out, idna, strlen(idna));

  } else {

    out->data = (unsigned char *)idna;

    out->size = strlen(idna);

    idna = NULL;

    ret = 0;

  }

fail:

  idn2_free(idna);

  gnutls_free(istr.data);

  return ret;

}

/**

 * gnutls_idna_reverse_map:

 * @input: contain the ACE (IDNA) formatted domain name

 * @ilen: the length of the provided string

 * @out: the result in an null-terminated allocated UTF-8 string

 * @flags: should be zero

 *

 * This function will convert an ACE (ASCII-encoded) domain name to a UTF-8 domain name.

 *

 * If GnuTLS is compiled without IDNA support, then this function

 * will return %GNUTLS_E_UNIMPLEMENTED_FEATURE.

 *

 * Note also, that this function will return an empty string if an

 * empty string is provided as input.

 *

 * Returns: A negative error code on error, or 0 on success.

 *

 * Since: 3.5.8

 **/

int gnutls_idna_reverse_map(const char *input, unsigned ilen,

          gnutls_datum_t *out, unsigned flags)

{

  char *u8 = NULL;

  int rc, ret;

  gnutls_datum_t istr;

  if (ilen == 0) {

    out->data = (uint8_t *)gnutls_strdup("");

    out->size = 0;

    if (out->data == NULL)

      return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);

    return 0;

  }

  ret = _gnutls_set_strdatum(&istr, input, ilen);

  if (ret < 0) {

    gnutls_assert();

    return ret;

  }

  /* currently libidn2 just converts single labels, thus a wrapper function */

  rc = idn2_to_unicode_8z8z((char *)istr.data, &u8, 0);

  if (rc != IDN2_OK) {

    gnutls_assert();

    _gnutls_debug_log(

      "unable to convert ACE name '%s' to UTF-8 format: %s\n",

      istr.data, idn2_strerror(rc));

    ret = GNUTLS_E_INVALID_UTF8_STRING;

    goto fail;

  }

  if (gnutls_malloc != malloc) {

    ret = _gnutls_set_strdatum(out, u8, strlen(u8));

  } else {

    out->data = (unsigned char *)u8;

    out->size = strlen(u8);

    u8 = NULL;

    ret = 0;

  }

fail:

  idn2_free(u8);

  gnutls_free(istr.data);

  return ret;

}

#else /* no HAVE_LIBIDN2 */

#undef gnutls_idna_map

int gnutls_idna_map(const char *input, unsigned ilen, gnutls_datum_t *out,

        unsigned flags)

{

  if (!_gnutls_str_is_print(input, ilen)) {

    return gnutls_assert_val(GNUTLS_E_UNIMPLEMENTED_FEATURE);

  }

  return _gnutls_set_strdatum(out, input, ilen);

}

int gnutls_idna_reverse_map(const char *input, unsigned ilen,

          gnutls_datum_t *out, unsigned flags)

{

  return gnutls_assert_val(GNUTLS_E_UNIMPLEMENTED_FEATURE);

}

#endif /* HAVE_LIBIDN2 */

int _gnutls_idna_email_map(const char *input, unsigned ilen,

         gnutls_datum_t *output)

{

  const char *p = input;

  while (*p != 0 && *p != '@') {

    if (!c_isprint(*p))

      return gnutls_assert_val(GNUTLS_E_INVALID_UTF8_EMAIL);

    p++;

  }

  if (_gnutls_str_is_print(input, ilen)) {

    return _gnutls_set_strdatum(output, input, ilen);

  }

  if (*p == '@') {

    unsigned name_part = p - input;

    int ret;

    gnutls_datum_t domain;

    ret = gnutls_idna_map(p + 1, ilen - name_part - 1, &domain, 0);

    if (ret < 0)

      return gnutls_assert_val(ret);

    output->data = gnutls_malloc(name_part + 1 + domain.size + 1);

    if (output->data == NULL) {

      gnutls_free(domain.data);

      return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);

    }

    memcpy(output->data, input, name_part);

    output->data[name_part] = '@';

    memcpy(&output->data[name_part + 1], domain.data, domain.size);

    output->data[name_part + domain.size + 1] = 0;

    output->size = name_part + domain.size + 1;

    gnutls_free(domain.data);

    return 0;

  } else {

    return gnutls_assert_val(GNUTLS_E_INVALID_UTF8_EMAIL);

  }

}

int _gnutls_idna_email_reverse_map(const char *input, unsigned ilen,

           gnutls_datum_t *output)

{

  const char *p = input;

  while (*p != 0 && *p != '@') {

    if (!c_isprint(*p))

      return gnutls_assert_val(GNUTLS_E_INVALID_UTF8_EMAIL);

    p++;

  }

  if (*p == '@') {

    unsigned name_part = p - input;

    int ret;

    gnutls_datum_t domain;

    ret = gnutls_idna_reverse_map(p + 1, ilen - name_part - 1,

                &domain, 0);

    if (ret < 0)

      return gnutls_assert_val(ret);

    output->data = gnutls_malloc(name_part + 1 + domain.size + 1);

    if (output->data == NULL) {

      gnutls_free(domain.data);

      return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);

    }

    memcpy(output->data, input, name_part);

    output->data[name_part] = '@';

    memcpy(&output->data[name_part + 1], domain.data, domain.size);

    output->data[name_part + domain.size + 1] = 0;

    output->size = name_part + domain.size + 1;

    gnutls_free(domain.data);

    return 0;

  } else {

    return gnutls_assert_val(GNUTLS_E_INVALID_UTF8_EMAIL);

  }

}