/*

 * Copyright (C) 2002-2012 Free Software Foundation, Inc.

 * 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 <num.h>

#include "str.h"

#include <stdarg.h>

#include <c-ctype.h>

#include <intprops.h>

#include <nettle/base64.h>

#include "extras/hex.h"

/* These functions are like strcat, strcpy. They only

 * do bound checking (they shouldn't cause buffer overruns),

 * and they always produce null terminated strings.

 *

 * They should be used only with null terminated strings.

 */

void _gnutls_str_cat(char *dest, size_t dest_tot_size, const char *src)

{

	size_t str_size = strlen(src);

	size_t dest_size = strlen(dest);

	if (dest_tot_size - dest_size > str_size) {

		strcat(dest, src);

	} else {

		if (dest_tot_size - dest_size > 0) {

			strncat(dest, src,

				(dest_tot_size - dest_size) - 1);

			dest[dest_tot_size - 1] = 0;

		}

	}

}

void _gnutls_str_cpy(char *dest, size_t dest_tot_size, const char *src)

{

	size_t str_size = strlen(src);

	if (dest_tot_size > str_size) {

		strcpy(dest, src);

	} else {

		if (dest_tot_size > 0) {

			memcpy(dest, src, (dest_tot_size) - 1);

			dest[dest_tot_size - 1] = 0;

		}

	}

}

void _gnutls_buffer_init(gnutls_buffer_st * str)

{

	str->data = str->allocd = NULL;

	str->max_length = 0;

	str->length = 0;

}

void _gnutls_buffer_clear(gnutls_buffer_st * str)

{

	if (str == NULL || str->allocd == NULL)

		return;

	gnutls_free(str->allocd);

	str->data = NULL;

	str->max_length = 0;

	str->length = 0;

}

#define MIN_CHUNK 1024

static void align_allocd_with_data(gnutls_buffer_st * dest)

{

	assert(dest->allocd != NULL);

	assert(dest->data != NULL);

	if (dest->length)

		memmove(dest->allocd, dest->data, dest->length);

	dest->data = dest->allocd;

}

/**

 * gnutls_buffer_append_data:

 * @dest: the buffer to append to

 * @data: the data

 * @data_size: the size of @data

 *

 * Appends the provided @data to the destination buffer.

 *

 * Returns: %GNUTLS_E_SUCCESS on success, otherwise a negative error code.

 *

 * Since: 3.4.0

 **/

int

gnutls_buffer_append_data(gnutls_buffer_t dest, const void *data,

			   size_t data_size)

{

	size_t const tot_len = data_size + dest->length;

	size_t const unused = MEMSUB(dest->data, dest->allocd);

	if (unlikely(dest->data != NULL && dest->allocd == NULL))

		return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

	if (data_size == 0)

		return 0;

	if (unlikely(sizeof(size_t) == 4 &&

	    INT_ADD_OVERFLOW (((ssize_t)MAX(data_size, MIN_CHUNK)), ((ssize_t)dest->length)))) {

		return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);

	}

	if (dest->max_length >= tot_len) {

		if (dest->max_length - unused <= tot_len) {

			align_allocd_with_data(dest);

		}

	} else {

		size_t const new_len =

		    MAX(data_size, MIN_CHUNK) + MAX(dest->max_length,

						    MIN_CHUNK);

		dest->allocd = gnutls_realloc_fast(dest->allocd, new_len);

		if (dest->allocd == NULL) {

			gnutls_assert();

			return GNUTLS_E_MEMORY_ERROR;

		}

		dest->max_length = new_len;

		dest->data = dest->allocd + unused;

		align_allocd_with_data(dest);

	}

	assert(dest->data != NULL);

	memcpy(&dest->data[dest->length], data, data_size);

	dest->length = tot_len;

	return 0;

}

int _gnutls_buffer_resize(gnutls_buffer_st * dest, size_t new_size)

{

	if (unlikely(dest->data != NULL && dest->allocd == NULL))

		return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

	if (dest->max_length >= new_size) {

		size_t unused = MEMSUB(dest->data, dest->allocd);

		if (dest->max_length - unused <= new_size) {

			align_allocd_with_data(dest);

		}

		return 0;

	} else {

		size_t unused = MEMSUB(dest->data, dest->allocd);

		size_t alloc_len =

		    MAX(new_size, MIN_CHUNK) + MAX(dest->max_length,

						   MIN_CHUNK);

		dest->allocd =

		    gnutls_realloc_fast(dest->allocd, alloc_len);

		if (dest->allocd == NULL) {

			gnutls_assert();

			return GNUTLS_E_MEMORY_ERROR;

		}

		dest->max_length = alloc_len;

		dest->data = dest->allocd + unused;

		align_allocd_with_data(dest);

		return 0;

	}

}

/* Appends the provided string. The null termination byte is appended

 * but not included in length.

 */

int _gnutls_buffer_append_str(gnutls_buffer_st * dest, const char *src)

{

	int ret;

	ret = _gnutls_buffer_append_data(dest, src, strlen(src) + 1);

	if (ret >= 0)

		dest->length--;

	return ret;

}

/* returns data from a string in a constant buffer.

 * The data will NOT be valid if buffer is released or

 * data are appended in the buffer.

 */

void

_gnutls_buffer_pop_datum(gnutls_buffer_st * str, gnutls_datum_t * data,

			 size_t req_size)

{

	if (str->length == 0) {

		data->data = NULL;

		data->size = 0;

		return;

	}

	if (req_size > str->length)

		req_size = str->length;

	data->data = str->data;

	data->size = req_size;

	str->data += req_size;

	str->length -= req_size;

	/* if string becomes empty start from beginning */

	if (str->length == 0) {

		str->data = str->allocd;

	}

	return;

}

/* converts the buffer to a datum if possible. After this call

 * (failed or not) the buffer should be considered deinitialized.

 */

int _gnutls_buffer_to_datum(gnutls_buffer_st * str, gnutls_datum_t * data, unsigned is_str)

{

	int ret;

	if (str->length == 0) {

		data->data = NULL;

		data->size = 0;

		ret = 0;

		goto fail;

	}

	if (is_str) {

		ret = _gnutls_buffer_append_data(str, "\x00", 1);

		if (ret < 0) {

			gnutls_assert();

			goto fail;

		}

	}

	if (str->allocd != str->data) {

		data->data = gnutls_malloc(str->length);

		if (data->data == NULL) {

			gnutls_assert();

			ret = GNUTLS_E_MEMORY_ERROR;

			goto fail;

		}

		memcpy(data->data, str->data, str->length);

		data->size = str->length;

		_gnutls_buffer_clear(str);

	} else {

		data->data = str->data;

		data->size = str->length;

		_gnutls_buffer_init(str);

	}

	if (is_str) {

		data->size--;

	}

	return 0;

 fail:

	_gnutls_buffer_clear(str);

	return ret;

}

/* returns data from a string in a constant buffer. Will

 * fail with GNUTLS_E_PARSING_ERROR, if the string has not enough data.

 */

int

_gnutls_buffer_pop_data(gnutls_buffer_st * str, void *data,

			size_t req_size)

{

	gnutls_datum_t tdata;

	_gnutls_buffer_pop_datum(str, &tdata, req_size);

	if (tdata.data == NULL || tdata.size != req_size) {

		return GNUTLS_E_PARSING_ERROR;

	}

	memcpy(data, tdata.data, tdata.size);

	return 0;

}

int

_gnutls_buffer_append_printf(gnutls_buffer_st * dest, const char *fmt, ...)

{

	va_list args;

	int len;

	char *str = NULL;

	va_start(args, fmt);

	len = vasprintf(&str, fmt, args);

	va_end(args);

	if (len < 0 || !str)

		return -1;

	len = _gnutls_buffer_append_str(dest, str);

	free(str);

	return len;

}

static int

_gnutls_buffer_insert_data(gnutls_buffer_st * dest, int pos,

			   const void *str, size_t str_size)

{

	size_t orig_length = dest->length;

	int ret;

	ret = _gnutls_buffer_resize(dest, dest->length + str_size);	/* resize to make space */

	if (ret < 0)

		return ret;

	assert(dest->data != NULL);

	memmove(&dest->data[pos + str_size], &dest->data[pos],

		orig_length - pos);

	memcpy(&dest->data[pos], str, str_size);

	dest->length += str_size;

	return 0;

}

static void

_gnutls_buffer_delete_data(gnutls_buffer_st * dest, int pos,

			   size_t str_size)

{

	memmove(&dest->data[pos], &dest->data[pos + str_size],

		dest->length - pos - str_size);

	dest->length -= str_size;

	return;

}

int

_gnutls_buffer_append_escape(gnutls_buffer_st * dest, const void *data,

			     size_t data_size, const char *invalid_chars)

{

	int rv = -1;

	char t[5];

	unsigned int pos = dest->length;

	rv = _gnutls_buffer_append_data(dest, data, data_size);

	if (rv < 0)

		return gnutls_assert_val(rv);

	while (pos < dest->length) {

		if (dest->data[pos] == '\\'

			|| strchr(invalid_chars, dest->data[pos])

			|| !c_isgraph(dest->data[pos])) {

			snprintf(t, sizeof(t), "%%%.2X",

				 (unsigned int) dest->data[pos]);

			_gnutls_buffer_delete_data(dest, pos, 1);

			if (_gnutls_buffer_insert_data(dest, pos, t, 3) < 0) {

				rv = -1;

				goto cleanup;

			}

			pos += 3;

		} else

			pos++;

	}

	rv = 0;

      cleanup:

	return rv;

}

int _gnutls_buffer_unescape(gnutls_buffer_st * dest)

{

	int rv = -1;

	unsigned int pos = 0;

	while (pos < dest->length) {

		if (dest->data[pos] == '%') {

			if (pos + 1 < dest->length && dest->data[pos + 1] == '%') {

				// %% -> %

				_gnutls_buffer_delete_data(dest, pos, 1);

			} else if (pos + 2 < dest->length && c_isxdigit(dest->data[pos + 1]) && c_isxdigit(dest->data[pos + 2])) {

				unsigned char x;

				hex_decode((char *) dest->data + pos + 1, 2, &x, 1);

				_gnutls_buffer_delete_data(dest, pos, 3);

				_gnutls_buffer_insert_data(dest, pos, &x, 1);

			}

		}

		pos++;

	}

	rv = 0;

	return rv;

}

/* Converts the given string (old) to hex. A buffer must be provided

 * to hold the new hex string. The new string will be null terminated.

 * If the buffer does not have enough space to hold the string, a

 * truncated hex string is returned (always null terminated).

 */

char *_gnutls_bin2hex(const void *_old, size_t oldlen,

		      char *buffer, size_t buffer_size,

		      const char *separator)

{

	unsigned int i, j;

	const uint8_t *old = _old;

	int step = 2;

	const char empty[] = "";

	if (separator != NULL && separator[0] != 0)

		step = 3;

	else

		separator = empty;

	if (buffer_size < 3) {

		gnutls_assert();

		return NULL;

	}

	i = j = 0;

	sprintf(&buffer[j], "%.2x", old[i]);

	j += 2;

	i++;

	for (; i < oldlen && j + step < buffer_size; j += step) {

		sprintf(&buffer[j], "%s%.2x", separator, old[i]);

		i++;

	}

	buffer[j] = '\0';

	return buffer;

}

/**

 * gnutls_hex2bin:

 * @hex_data: string with data in hex format

 * @hex_size: size of hex data

 * @bin_data: output array with binary data

 * @bin_size: when calling should hold maximum size of @bin_data,

 *	    on return will hold actual length of @bin_data.

 *

 * Convert a buffer with hex data to binary data. This function

 * unlike gnutls_hex_decode() can parse hex data with separators

 * between numbers. That is, it ignores any non-hex characters.

 *

 * Returns: %GNUTLS_E_SUCCESS on success, otherwise a negative error code.

 *

 * Since: 2.4.0

 **/

int

gnutls_hex2bin(const char *hex_data,

	       size_t hex_size, void *bin_data, size_t * bin_size)

{

	return _gnutls_hex2bin(hex_data, hex_size, (void *) bin_data,

			       bin_size);

}

int

_gnutls_hex2bin(const char *hex_data, size_t hex_size, uint8_t * bin_data,

		size_t * bin_size)

{

	unsigned int i, j;

	uint8_t hex2_data[3];

	unsigned long val;

	hex2_data[2] = 0;

	for (i = j = 0; i < hex_size;) {

		if (!isxdigit(hex_data[i])) {	/* skip non-hex such as the ':' in 00:FF */

			i++;

			continue;

		}

		if (j >= *bin_size) {

			gnutls_assert();

			return GNUTLS_E_SHORT_MEMORY_BUFFER;

		}

		if (i+1 >= hex_size)

			return gnutls_assert_val(GNUTLS_E_PARSING_ERROR);

		hex2_data[0] = hex_data[i];

		hex2_data[1] = hex_data[i + 1];

		i += 2;

		val = strtoul((char *) hex2_data, NULL, 16);

		if (val == ULONG_MAX) {

			gnutls_assert();

			return GNUTLS_E_PARSING_ERROR;

		}

		bin_data[j] = val;

		j++;

	}

	*bin_size = j;

	return 0;

}

/**

 * gnutls_hex_decode2:

 * @hex_data: contain the encoded data

 * @result: the result in an allocated string

 *

 * This function will decode the given encoded data, using the hex

 * encoding used by PSK password files.

 *

 * Returns: %GNUTLS_E_PARSING_ERROR on invalid hex data, or 0 on success.

 **/

int

gnutls_hex_decode2(const gnutls_datum_t * hex_data, gnutls_datum_t *result)

{

	int ret;

	int size = hex_data_size(hex_data->size);

	result->data = gnutls_malloc(size);

	if (result->data == NULL) {

		gnutls_assert();

		return GNUTLS_E_MEMORY_ERROR;

	}

	result->size = size;

	ret = hex_decode((char *) hex_data->data, hex_data->size,

			 result->data, result->size);

	if (ret == 0) {

		gnutls_assert();

		gnutls_free(result->data);

		return GNUTLS_E_PARSING_ERROR;

	}

	return 0;

}

/**

 * gnutls_hex_decode:

 * @hex_data: contain the encoded data

 * @result: the place where decoded data will be copied

 * @result_size: holds the size of the result

 *

 * This function will decode the given encoded data, using the hex

 * encoding used by PSK password files.

 *

 * Initially @result_size must hold the maximum size available in

 * @result, and on return it will contain the number of bytes written.

 *

 * Returns: %GNUTLS_E_SHORT_MEMORY_BUFFER if the buffer given is not

 *   long enough, %GNUTLS_E_PARSING_ERROR on invalid hex data, or 0 on success.

 **/

int

gnutls_hex_decode(const gnutls_datum_t * hex_data, void *result,

		  size_t * result_size)

{

	int ret;

	size_t size = hex_data_size(hex_data->size);

	if (*result_size < size) {

		gnutls_assert();

		return GNUTLS_E_SHORT_MEMORY_BUFFER;

	}

	ret = hex_decode((char *) hex_data->data, hex_data->size,

			 result, size);

	if (ret == 0) {

		return gnutls_assert_val(GNUTLS_E_PARSING_ERROR);

	}

	*result_size = size;

	return 0;

}

/**

 * gnutls_hex_encode:

 * @data: contain the raw data

 * @result: the place where hex data will be copied

 * @result_size: holds the size of the result

 *

 * This function will convert the given data to printable data, using

 * the hex encoding, as used in the PSK password files.

 *

 * Note that the size of the result includes the null terminator.

 *

 * Returns: %GNUTLS_E_SHORT_MEMORY_BUFFER if the buffer given is not

 * long enough, or 0 on success.

 **/

int

gnutls_hex_encode(const gnutls_datum_t * data, char *result,

		  size_t * result_size)

{

	int ret;

	size_t size = hex_str_size(data->size);

	if (*result_size < size) {

		gnutls_assert();

		return GNUTLS_E_SHORT_MEMORY_BUFFER;

	}

	ret = hex_encode(data->data, data->size, result, *result_size);

	if (ret == 0) {

		return gnutls_assert_val(GNUTLS_E_PARSING_ERROR);

	}

	*result_size = size;

	return 0;

}

/**

 * gnutls_hex_encode2:

 * @data: contain the raw data

 * @result: the result in an allocated string

 *

 * This function will convert the given data to printable data, using

 * the hex encoding, as used in the PSK password files.

 *

 * Note that the size of the result does NOT include the null terminator.

 *

 * Returns: %GNUTLS_E_SUCCESS on success, otherwise a negative error code.

 **/

int

gnutls_hex_encode2(const gnutls_datum_t * data, gnutls_datum_t *result)

{

	int ret;

	int size = hex_str_size(data->size);

	result->data = gnutls_malloc(size);

	if (result->data == NULL) {

		gnutls_assert();

		return GNUTLS_E_MEMORY_ERROR;

	}

	ret = hex_encode((char*)data->data, data->size, (char*)result->data, size);

	if (ret == 0) {

		gnutls_free(result->data);

		return gnutls_assert_val(GNUTLS_E_PARSING_ERROR);

	}

	result->size = size-1;

	return 0;

}

static int

hostname_compare_raw(const char *certname,

			 size_t certnamesize, const char *hostname)

{

	if (certnamesize == strlen(hostname) && memcmp(hostname, certname, certnamesize) == 0)

		return 1;

	return 0;

}

static int

hostname_compare_ascii(const char *certname,

			 size_t certnamesize, const char *hostname)

{

	for (;

	     *certname && *hostname

	     && c_toupper(*certname) == c_toupper(*hostname);

	     certname++, hostname++, certnamesize--);

	/* the strings are the same */

	if (certnamesize == 0 && *hostname == '\0')

		return 1;

	return 0;

}

/* compare hostname against certificate, taking account of wildcards

 * return 1 on success or 0 on error

 *

 * note: certnamesize is required as X509 certs can contain embedded NULs in

 * the strings such as CN or subjectAltName.

 *

 * Wildcards are taken into account only if they are the leftmost

 * component, and if the string is ascii only (partial advice from rfc6125)

 *

 */

int

_gnutls_hostname_compare(const char *certname,

			 size_t certnamesize, const char *hostname, unsigned vflags)

{

	char *p;

	unsigned i;

	for (i=0;i

		if (c_isprint(certname[i]) == 0)

			return hostname_compare_raw(certname, certnamesize, hostname);

	}

	if (*certname == '*' && !(vflags & GNUTLS_VERIFY_DO_NOT_ALLOW_WILDCARDS)) {

		/* a wildcard certificate */

		/* ensure that we have at least two domain components after

		 * the wildcard. */

		p = strrchr(certname, '.');

		if (p == NULL || strchr(certname, '.') == p || p[1] == 0) {

			return 0;

		}

		certname++;

		certnamesize--;

		while (1) {

			if (hostname_compare_ascii(certname, certnamesize, hostname))

				return 1;

			/* wildcards are only allowed to match a single domain

			   component or component fragment */

			if (*hostname == '\0' || *hostname == '.')

				break;

			hostname++;

		}

		return 0;

	} else {

		return hostname_compare_ascii(certname, certnamesize, hostname);

	}

}

int

_gnutls_buffer_append_prefix(gnutls_buffer_st * buf, int pfx_size,

			     size_t data_size)

{

	uint8_t ss[4];

	if (pfx_size == 32) {

		_gnutls_write_uint32(data_size, ss);

		pfx_size = 4;

	} else if (pfx_size == 24) {

		_gnutls_write_uint24(data_size, ss);

		pfx_size = 3;

	} else if (pfx_size == 16) {

		_gnutls_write_uint16(data_size, ss);

		pfx_size = 2;

	} else if (pfx_size == 8) {

		ss[0] = data_size;

		pfx_size = 1;

	} else

		return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

	return _gnutls_buffer_append_data(buf, ss, pfx_size);

}

/* Reads an uint32 number from the buffer. If check is non zero it will also check whether

 * the number read, is less than the data in the buffer

 */

int

_gnutls_buffer_pop_prefix32(gnutls_buffer_st * buf, size_t * data_size,

			    int check)

{

	size_t size;

	if (buf->length < 4) {

		gnutls_assert();

		return GNUTLS_E_PARSING_ERROR;

	}

	size = _gnutls_read_uint32(buf->data);

	if (check && size > buf->length - 4) {

		gnutls_assert();

		return GNUTLS_E_PARSING_ERROR;

	}

	buf->data += 4;

	buf->length -= 4;

	*data_size = size;

	return 0;

}

int _gnutls_buffer_pop_prefix8(gnutls_buffer_st *buf, uint8_t *data, int check)

{

	if (buf->length < 1) {

		gnutls_assert();

		return GNUTLS_E_PARSING_ERROR;

	}

	*data = buf->data[0];

	if (check && *data > buf->length - 1) {

		gnutls_assert();

		return GNUTLS_E_PARSING_ERROR;

	}

	buf->data++;

	buf->length--;

	return 0;

}

int

_gnutls_buffer_pop_prefix24(gnutls_buffer_st * buf, size_t * data_size,

			    int check)

{

	size_t size;

	if (buf->length < 3) {

		gnutls_assert();

		return GNUTLS_E_PARSING_ERROR;

	}

	size = _gnutls_read_uint24(buf->data);

	if (check && size > buf->length - 3) {

		gnutls_assert();

		return GNUTLS_E_PARSING_ERROR;

	}

	buf->data += 3;

	buf->length -= 3;

	*data_size = size;

	return 0;

}

int

_gnutls_buffer_pop_datum_prefix32(gnutls_buffer_st * buf,

				  gnutls_datum_t * data)

{

	size_t size;

	int ret;

	ret = _gnutls_buffer_pop_prefix32(buf, &size, 1);

	if (ret < 0) {

		gnutls_assert();

		return ret;

	}

	if (size > 0) {

		size_t osize = size;

		_gnutls_buffer_pop_datum(buf, data, size);

		if (osize != data->size) {

			gnutls_assert();

			return GNUTLS_E_PARSING_ERROR;

		}

	} else {

		data->size = 0;

		data->data = NULL;

	}

	return 0;

}

int

_gnutls_buffer_pop_datum_prefix16(gnutls_buffer_st * buf,

				  gnutls_datum_t * data)

{

	size_t size;

	if (buf->length < 2) {

		gnutls_assert();

		return GNUTLS_E_PARSING_ERROR;

	}

	size = _gnutls_read_uint16(buf->data);