path: root/lib/gnutls_str.c

/*
 * Copyright (C) 2002-2012 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 <http://www.gnu.org/licenses/>
 *
 */

#include <gnutls_int.h>
#include <gnutls_errors.h>
#include <gnutls_num.h>
#include <gnutls_str.h>
#include <stdarg.h>
#include <c-ctype.h>

/* These function 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)
        {
          strncpy (dest, src, (dest_tot_size) - 1);
          dest[dest_tot_size - 1] = 0;
        }
    }
}

void
_gnutls_mem_cpy (char *dest, size_t dest_tot_size, const char *src,
                 size_t src_size)
{

  if (dest_tot_size >= src_size)
    {
      memcpy (dest, src, src_size);
    }
  else
    {
      if (dest_tot_size > 0)
        {
          memcpy (dest, src, dest_tot_size);
        }
    }
}

void
_gnutls_buffer_init (gnutls_buffer_st * str)
{
  str->data = str->allocd = NULL;
  str->max_length = 0;
  str->length = 0;
}

void _gnutls_buffer_replace_data( gnutls_buffer_st * buf, gnutls_datum_t * data)
{
    gnutls_free(buf->allocd);
    buf->allocd = buf->data = data->data;
    buf->max_length = buf->length = data->size;
}

void
_gnutls_buffer_clear (gnutls_buffer_st * str)
{
  if (str == NULL || str->allocd == NULL)
    return;
  gnutls_free (str->allocd);

  str->data = str->allocd = NULL;
  str->max_length = 0;
  str->length = 0;
}

#define MIN_CHUNK 1024

int
_gnutls_buffer_append_data (gnutls_buffer_st * dest, const void *data,
                            size_t data_size)
{
  size_t tot_len = data_size + dest->length;

  if (data_size == 0) return 0;

  if (dest->max_length >= tot_len)
    {
      size_t unused = MEMSUB (dest->data, dest->allocd);

      if (dest->max_length - unused <= tot_len)
        {
          if (dest->length && dest->data)
            memmove (dest->allocd, dest->data, dest->length);

          dest->data = dest->allocd;
        }
      memmove (&dest->data[dest->length], data, data_size);
      dest->length = tot_len;

      return tot_len;
    }
  else
    {
      size_t unused = MEMSUB (dest->data, dest->allocd);
      size_t 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;

      if (dest->length && dest->data)
        memmove (dest->allocd, dest->data, dest->length);
      dest->data = dest->allocd;

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

      return tot_len;
    }
}

int
_gnutls_buffer_resize (gnutls_buffer_st * dest, size_t new_size)
{
  if (dest->max_length >= new_size)
    {
      size_t unused = MEMSUB (dest->data, dest->allocd);
      if (dest->max_length - unused <= new_size)
        {
          if (dest->length && dest->data)
            memmove (dest->allocd, dest->data, dest->length);
          dest->data = dest->allocd;
        }

      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;

      if (dest->length && dest->data)
        memmove (dest->allocd, dest->data, dest->length);
      dest->data = dest->allocd;

      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 begining */
  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)
{

  if (str->length == 0)
    {
      data->data = NULL;
      data->size = 0;
      _gnutls_buffer_clear (str);
      return 0;
    }

  if (str->allocd != str->data)
    {
      data->data = gnutls_malloc (str->length);
      if (data->data == NULL)
        {
          gnutls_assert ();
          _gnutls_buffer_clear (str);
          return GNUTLS_E_MEMORY_ERROR;
        }
      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);
    }

  return 0;
}

/* returns data from a string in a constant buffer.
 */
void
_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);

  *req_size = tdata.size;
  memcpy (data, tdata.data, tdata.size);

  return;
}

int
_gnutls_buffer_append_printf (gnutls_buffer_st * dest, const char *fmt, ...)
{
  va_list args;
  int len;
  char *str;

  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;

  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_escape (gnutls_buffer_st * dest, int all,
                       const char *const invalid_chars)
{
  int rv = -1;
  char t[5];
  unsigned int pos = 0;

  while (pos < dest->length)
    {

      if (all != 0 || (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] == '%')
        {
          char b[3];
          unsigned int u;
          unsigned char x;

          b[0] = dest->data[pos + 1];
          b[1] = dest->data[pos + 2];
          b[2] = 0;

          sscanf (b, "%02x", &u);

          x = u;

          _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.
 *
 * 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;
        }

      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_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.
 *
 * Note that hex_data should be null terminated.
 *
 * Returns: %GNUTLS_E_SHORT_MEMORY_BUFFER if the buffer given is not
 *   long enough, or 0 on success.
 **/
int
gnutls_hex_decode (const gnutls_datum_t * hex_data, void *result,
                   size_t * result_size)
{
  int ret;

  ret =
    _gnutls_hex2bin ((char*)hex_data->data, hex_data->size, (uint8_t *) result,
                     result_size);
  if (ret < 0)
    return ret;

  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.
 *
 * 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)
{
  size_t res = data->size + data->size + 1;

  if (*result_size < res)
    {
      gnutls_assert ();
      return GNUTLS_E_SHORT_MEMORY_BUFFER;
    }

  _gnutls_bin2hex (data->data, data->size, result, *result_size, NULL);
  *result_size = res;

  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.
 *
 * @level: is used for recursion. Use 0 when you call this function.
 */
int
_gnutls_hostname_compare (const char *certname,
                          size_t certnamesize, const char *hostname, int level)
{

  if (level > 5)
    return 0;

  /* find the first different character */
  for (; *certname && *hostname && c_toupper (*certname) == c_toupper (*hostname);
       certname++, hostname++, certnamesize--)
    ;

  /* the strings are the same */
  if (certnamesize == 0 && *hostname == '\0')
    return 1;

  if (*certname == '*')
    {
      /* a wildcard certificate */

      certname++;
      certnamesize--;

      while (1)
        {
          /* Use a recursive call to allow multiple wildcards */
          if (_gnutls_hostname_compare (certname, certnamesize, hostname, level+1))
            return 1;

          /* wildcards are only allowed to match a single domain
             component or component fragment */
          if (*hostname == '\0' || *hostname == '.')
            break;
          hostname++;
        }

      return 0;
    }

  return 0;
}

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_prefix (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_datum_prefix (gnutls_buffer_st * buf,
                                 gnutls_datum_t * data)
{
  size_t size;
  int ret;

  ret = _gnutls_buffer_pop_prefix (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_append_data_prefix (gnutls_buffer_st * buf, 
    int pfx_size, const void *data, size_t data_size)
{
int ret = 0, ret1;

  ret1 = _gnutls_buffer_append_prefix (buf, pfx_size, data_size);
  if (ret1 < 0)
    return gnutls_assert_val(ret1);

  if (data_size > 0)
    {
      ret = _gnutls_buffer_append_data (buf, data, data_size);

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

  return ret + ret1;
}

int _gnutls_buffer_append_mpi (gnutls_buffer_st * buf, int pfx_size, bigint_t mpi, int lz)
{
gnutls_datum_t dd;
int ret;

  if (lz)
    ret = _gnutls_mpi_dprint_lz (mpi, &dd);
  else
    ret = _gnutls_mpi_dprint (mpi, &dd);

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

  ret = _gnutls_buffer_append_data_prefix(buf, pfx_size, dd.data, dd.size);
  
  _gnutls_free_datum(&dd);
  
  return ret;
}

int
_gnutls_buffer_pop_data_prefix (gnutls_buffer_st * buf, void *data,
                                size_t * data_size)
{
  size_t size;
  int ret;

  ret = _gnutls_buffer_pop_prefix (buf, &size, 1);
  if (ret < 0)
    {
      gnutls_assert ();
      return ret;
    }

  if (size > 0)
    _gnutls_buffer_pop_data (buf, data, data_size);

  return 0;
}

void
_gnutls_buffer_hexprint (gnutls_buffer_st * str,
			 const void *_data, size_t len)
{
  size_t j;
  const unsigned char* data = _data;

  if (len == 0)
    _gnutls_buffer_append_str (str, "00");
  else
    {
      for (j = 0; j < len; j++)
        _gnutls_buffer_append_printf (str, "%.2x", (unsigned) data[j]);
    }
}

void
_gnutls_buffer_hexdump (gnutls_buffer_st * str, const void *_data, size_t len,
			const char *spc)
{
  size_t j;
  const unsigned char* data = _data;

  if (spc)
    _gnutls_buffer_append_str (str, spc);
  for (j = 0; j < len; j++)
    {
      if (((j + 1) % 16) == 0)
        {
          _gnutls_buffer_append_printf (str, "%.2x\n", (unsigned)data[j]);
          if (spc && j != (len - 1))
            _gnutls_buffer_append_str (str, spc);
        }
      else if (j == (len - 1))
        _gnutls_buffer_append_printf (str, "%.2x", (unsigned)data[j]);
      else
        _gnutls_buffer_append_printf (str, "%.2x:", (unsigned)data[j]);
    }
  if ((j % 16) != 0)
    _gnutls_buffer_append_str (str, "\n");
}

void
_gnutls_buffer_asciiprint (gnutls_buffer_st * str,
			   const char *data, size_t len)
{
  size_t j;

  for (j = 0; j < len; j++)
    if (c_isprint (data[j]))
      _gnutls_buffer_append_printf (str, "%c", (unsigned char) data[j]);
    else
      _gnutls_buffer_append_printf (str, ".");
}