/*

 * 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 <http://www.gnu.org/licenses/>

 *

 */

#include "gnutls_int.h"

#include "errors.h"

#include "str.h"

#include <unistr.h>

#ifdef HAVE_LIBIDN2

# include <idn2.h>

#if IDN2_VERSION_NUMBER < 0x02000000

# define idn2_to_ascii_8z idn2_lookup_u8

# define ICAST uint8_t

#else

# define ICAST char

#endif

/**

 * 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;

#if IDN2_VERSION_NUMBER >= 0x00140000

	/* IDN2_NONTRANSITIONAL automatically converts to lowercase

	 * IDN2_NFC_INPUT converts to NFC before toASCII conversion

	 *

	 * Since IDN2_NONTRANSITIONAL implicitely 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. */

	idn2_flags |= IDN2_NONTRANSITIONAL;

	idn2_tflags |= IDN2_TRANSITIONAL;

#endif

	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;

}

#if IDN2_VERSION_NUMBER < 0x02000000

int _idn2_punycode_decode(

	size_t input_length,

	const char input[],

	size_t *output_length,

	uint32_t output[],

	unsigned char case_flags[]);

static int idn2_to_unicode_8z8z(const char *src, char **dst, unsigned flags)

{

	int rc, run;

	size_t out_len = 0;

	const char *e, *s;

	char *p = NULL;

	for (run = 0; run < 2; run++) {

		if (run) {

			p = malloc(out_len + 1);

			if (!p)

				return IDN2_MALLOC;

			*dst = p;

		}

		out_len = 0;

		for (e = s = src; *e; s = e) {

			while (*e && *e != '.')

				e++;

			if (e - s > 4 && (s[0] == 'x' || s[0] == 'X') && (s[1] == 'n' || s[1] == 'N') && s[2] == '-' && s[3] == '-') {

				size_t u32len = IDN2_LABEL_MAX_LENGTH * 4;

				uint32_t u32[IDN2_LABEL_MAX_LENGTH * 4];

				uint8_t u8[IDN2_LABEL_MAX_LENGTH + 1];

				size_t u8len;

				rc = _idn2_punycode_decode(e - s - 4, s + 4, &u32len, u32, NULL);

				if (rc != IDN2_OK)

					return rc;

				u8len = sizeof(u8);

				if (u32_to_u8(u32, u32len, u8, &u8len) == NULL)

					return IDN2_ENCODING_ERROR;

				u8[u8len] = '\0';

				if (run)

					memcpy(*dst + out_len, u8, u8len);

				out_len += u8len;

			} else {

				if (run)

					memcpy(*dst + out_len, s, e - s);

				out_len += e - s;

			}

			if (*e) {

				e++;

				if (run)

					(*dst)[out_len] = '.';

				out_len++;

			}

		}

	}

	(*dst)[out_len] = 0;

	return IDN2_OK;

}

#endif

/**

 * 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);

	}

}