path: root/lib/gnutls_str.c

/*
 * Copyright (C) 2002, 2004, 2005, 2007, 2008, 2009, 2010 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 library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
 * USA
 *
 */

#include <gnutls_int.h>
#include <gnutls_errors.h>
#include <gnutls_num.h>
#include <gnutls_str.h>
#include <stdarg.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_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 (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 (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 (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;
    }
}

int
_gnutls_buffer_append_str (gnutls_buffer_st * dest, const char *src)
{
  return _gnutls_buffer_append_data (dest, src, strlen (src));
}

/* 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 the buffer
 * is at an usable state and might not be used or deinitialized */
int
_gnutls_buffer_to_datum (gnutls_buffer_st * str, gnutls_datum_t * data)
{

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

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

  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,
		       const char *const invalid_chars)
{
  int rv = -1;
  char t[5];
  int pos = 0;

  while (pos < dest->length)
    {

      if (dest->data[pos] == '\\' || strchr (invalid_chars, dest->data[pos])
	  || !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++;
    }

  rv = 0;

cleanup:

  return rv;
}

int
_gnutls_buffer_unescape (gnutls_buffer_st * dest)
{
  int rv = -1;
  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 opaque *old = _old;
  int step = 2;
  const char empty[] = "";

  if (separator != NULL && separator[0] != 0)
    step = 3;
  else
    separator = empty;

  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 *@bin_size should hold size of @bin_data,
 *            on return will hold actual size of @bin_data.
 *
 * Convert a buffer with hex data to binary data.
 *
 * Returns: %GNUTLS_E_SUCCESS on success, otherwise an error.
 *
 * Since: 2.4.0
 **/
int
gnutls_hex2bin (const char *hex_data,
		size_t hex_size, char *bin_data, size_t * bin_size)
{
  return _gnutls_hex2bin (hex_data, (int) hex_size, bin_data, bin_size);
}

int
_gnutls_hex2bin (const opaque * hex_data, int hex_size, opaque * bin_data,
		 size_t * bin_size)
{
  int i, j;
  opaque 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;
}


/* 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
 */
int
_gnutls_hostname_compare (const char *certname,
			  size_t certnamesize, const char *hostname)
{
  /* find the first different character */
  for (; *certname && *hostname && toupper (*certname) == 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))
	    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, size_t data_size)
{
  opaque ss[4];
  _gnutls_write_uint32 (data_size, ss);
  return _gnutls_buffer_append_data (buf, ss, 4);
}

/* 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, const void *data,
				   size_t data_size)
{
  _gnutls_buffer_append_prefix (buf, data_size);
  if (data_size > 0)
    return _gnutls_buffer_append_data (buf, data, data_size);

  return 0;
}

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;
}