tld.c

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/* tld.c --- Declarations for TLD restriction checking.
   Copyright (C) 2004-2024 Simon Josefsson.
   Copyright (C) 2003-2024 Free Software Foundation, Inc.
 
   Author: Thomas Jacob, Internet24.de
 
   This file is part of GNU Libidn.
 
   GNU Libidn is free software: you can redistribute it and/or
   modify it under the terms of either:
 
     * the GNU Lesser General Public License as published by the Free
       Software Foundation; either version 3 of the License, or (at
       your option) any later version.
 
   or
 
     * the GNU General Public License as published by the Free
       Software Foundation; either version 2 of the License, or (at
       your option) any later version.
 
   or both in parallel, as here.
 
   GNU Libidn 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
   General Public License for more details.
 
   You should have received copies of the GNU General Public License and
   the GNU Lesser General Public License along with this program.  If
   not, see <https://www.gnu.org/licenses/>. */
 
#include <config.h>
 
/* Get stringprep_utf8_to_ucs4, stringprep_locale_to_utf8. */
#include <stringprep.h>
 
/* Get strcmp(). */
#include <string.h>
 
/* Get specifications. */
#include <tld.h>
 
/* Array of built-in domain restriction structures.  See tlds.c.  */
extern const Tld_table *_tld_tables[];
 
const Tld_table *
tld_get_table (const char *tld, const Tld_table **tables)
{
  const Tld_table **tldtable = NULL;
 
  if (!tld || !tables)
    return NULL;
 
  for (tldtable = tables; *tldtable; tldtable++)
    if (!strcmp ((*tldtable)->name, tld))
      return *tldtable;
 
  return NULL;
}
 
const Tld_table *
tld_default_table (const char *tld, const Tld_table **overrides)
{
  const Tld_table *tldtable = NULL;
 
  if (!tld)
    return NULL;
 
  if (overrides)
    tldtable = tld_get_table (tld, overrides);
 
  if (!tldtable)
    tldtable = tld_get_table (tld, _tld_tables);
 
  return tldtable;
}
 
#define DOTP(c) ((c) == 0x002E || (c) == 0x3002 ||      \
                 (c) == 0xFF0E || (c) == 0xFF61)
 
int
tld_get_4 (const uint32_t *in, size_t inlen, char **out)
{
  const uint32_t *ipos;
  size_t olen;
 
  *out = NULL;
  if (!in || inlen == 0)
    return TLD_NODATA;
 
  ipos = &in[inlen - 1];
  olen = 0;
  /* Scan backwards for non(latin)letters. */
  while (ipos >= in && ((*ipos >= 0x41 && *ipos <= 0x5A) ||
                        (*ipos >= 0x61 && *ipos <= 0x7A)))
    ipos--, olen++;
 
  if (olen > 0 && ipos >= in && DOTP (*ipos))
    {
      /* Found something that appears a TLD. */
      char *out_s = malloc (sizeof (char) * (olen + 1));
      char *opos = out_s;
 
      if (!opos)
        return TLD_MALLOC_ERROR;
 
      ipos++;
      /* Transcribe to lowercase ascii string. */
      for (; ipos < &in[inlen]; ipos++, opos++)
        *opos = *ipos > 0x5A ? *ipos : *ipos + 0x20;
      *opos = 0;
      *out = out_s;
      return TLD_SUCCESS;
    }
 
  return TLD_NO_TLD;
}
 
int
tld_get_4z (const uint32_t *in, char **out)
{
  const uint32_t *ipos = in;
 
  if (!in)
    return TLD_NODATA;
 
  while (*ipos)
    ipos++;
 
  return tld_get_4 (in, ipos - in, out);
}
 
int
tld_get_z (const char *in, char **out)
{
  uint32_t *iucs;
  size_t i, ilen;
  int rc;
 
  ilen = strlen (in);
  iucs = calloc (ilen, sizeof (*iucs));
 
  if (!iucs)
    return TLD_MALLOC_ERROR;
 
  for (i = 0; i < ilen; i++)
    iucs[i] = in[i];
 
  rc = tld_get_4 (iucs, ilen, out);
 
  free (iucs);
 
  return rc;
}
 
/*
 * tld_checkchar - verify that character is permitted
 * @ch: 32 bit unicode character to check.
 * @tld: A #Tld_table data structure to check @ch against.
 *
 * Verify if @ch is either in [a-z0-9-.] or mentioned as a valid
 * character in @tld.
 *
 * Return value: Return the #Tld_rc value %TLD_SUCCESS if @ch is a
 *   valid character for the TLD @tld or if @tld is %NULL,
 *   %TLD_INVALID if @ch is invalid as defined by @tld.
 */
static int
_tld_checkchar (uint32_t ch, const Tld_table *tld)
{
  const Tld_table_element *s, *e, *m;
 
  if (!tld)
    return TLD_SUCCESS;
 
  /* Check for [-a-z0-9.]. */
  if ((ch >= 0x61 && ch <= 0x7A) ||
      (ch >= 0x30 && ch <= 0x39) || ch == 0x2D || DOTP (ch))
    return TLD_SUCCESS;
 
  s = tld->valid;
  e = s + tld->nvalid;
  while (s < e)
    {
      m = s + ((e - s) >> 1);
      if (ch < m->start)
        e = m;
      else if (ch > m->end)
        s = m + 1;
      else
        return TLD_SUCCESS;
    }
 
  return TLD_INVALID;
}
 
int
tld_check_4t (const uint32_t *in, size_t inlen, size_t *errpos,
              const Tld_table *tld)
{
  const uint32_t *ipos;
  int rc;
 
  if (!tld)                     /* No data for TLD so everything is valid. */
    return TLD_SUCCESS;
 
  ipos = in;
  while (ipos < &in[inlen])
    {
      rc = _tld_checkchar (*ipos, tld);
      if (rc != TLD_SUCCESS)
        {
          if (errpos)
            *errpos = ipos - in;
          return rc;
        }
      ipos++;
    }
  return TLD_SUCCESS;
}
 
int
tld_check_4tz (const uint32_t *in, size_t *errpos, const Tld_table *tld)
{
  const uint32_t *ipos = in;
 
  if (!ipos)
    return TLD_NODATA;
 
  while (*ipos)
    ipos++;
 
  return tld_check_4t (in, ipos - in, errpos, tld);
}
 
int
tld_check_4 (const uint32_t *in, size_t inlen, size_t *errpos,
             const Tld_table **overrides)
{
  const Tld_table *tld;
  char *domain;
  int rc;
 
  if (errpos)
    *errpos = 0;
 
  /* Get TLD name. */
  rc = tld_get_4 (in, inlen, &domain);
 
  if (rc != TLD_SUCCESS)
    {
      if (rc == TLD_NO_TLD)     /* No TLD, say OK */
        return TLD_SUCCESS;
      else
        return rc;
    }
 
  /* Retrieve appropriate data structure. */
  tld = tld_default_table (domain, overrides);
  free (domain);
 
  return tld_check_4t (in, inlen, errpos, tld);
}
 
int
tld_check_4z (const uint32_t *in, size_t *errpos, const Tld_table **overrides)
{
  const uint32_t *ipos = in;
 
  if (!ipos)
    return TLD_NODATA;
 
  while (*ipos)
    ipos++;
 
  return tld_check_4 (in, ipos - in, errpos, overrides);
}
 
int
tld_check_8z (const char *in, size_t *errpos, const Tld_table **overrides)
{
  uint32_t *iucs;
  size_t ilen;
  int rc;
 
  if (!in)
    return TLD_NODATA;
 
  iucs = stringprep_utf8_to_ucs4 (in, -1, &ilen);
 
  if (!iucs)
    return TLD_MALLOC_ERROR;
 
  rc = tld_check_4 (iucs, ilen, errpos, overrides);
 
  free (iucs);
 
  return rc;
}
 
int
tld_check_lz (const char *in, size_t *errpos, const Tld_table **overrides)
{
  char *utf8;
  int rc;
 
  if (!in)
    return TLD_NODATA;
 
  utf8 = stringprep_locale_to_utf8 (in);
  if (!utf8)
    return TLD_ICONV_ERROR;
 
 
  rc = tld_check_8z (utf8, errpos, overrides);
 
  free (utf8);
 
  return rc;
}