idna.c

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/* idna.c --- Convert to or from IDN strings.
 * Copyright (C) 2002, 2003, 2004  Simon Josefsson
 *
 * This file is part of GNU Libidn.
 *
 * GNU Libidn 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.
 *
 * 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with GNU Libidn; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
 *
 */

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <stdlib.h>
#include <string.h>
#include <stringprep.h>
#include <punycode.h>

#include "idna.h"

#define DOTP(c) ((c) == 0x002E || (c) == 0x3002 ||      \
                 (c) == 0xFF0E || (c) == 0xFF61)

/* Core functions */

int
idna_to_ascii_4i (const uint32_t * in, size_t inlen, char *out, int flags)
{
  size_t len, outlen;
  uint32_t *src;                /* XXX don't need to copy data? */
  int rc;

  /*
   * ToASCII consists of the following steps:
   *
   * 1. If all code points in the sequence are in the ASCII range (0..7F)
   * then skip to step 3.
   */

  {
    size_t i;
    int inasciirange;

    inasciirange = 1;
    for (i = 0; i < inlen; i++)
      if (in[i] > 0x7F)
        inasciirange = 0;
    if (inasciirange)
      {
        src = malloc (sizeof (in[0]) * (inlen + 1));
        if (src == NULL)
          return IDNA_MALLOC_ERROR;

        memcpy (src, in, sizeof (in[0]) * inlen);
        src[inlen] = 0;

        goto step3;
      }
  }

  /*
   * 2. Perform the steps specified in [NAMEPREP] and fail if there is
   * an error. The AllowUnassigned flag is used in [NAMEPREP].
   */

  {
    char *p;

    p = stringprep_ucs4_to_utf8 (in, inlen, NULL, NULL);
    if (p == NULL)
      return IDNA_MALLOC_ERROR;

    len = strlen (p);
    do
      {
        char *newp;

        len = 2 * len + 10;     /* XXX better guess? */
        newp = realloc (p, len);
        if (newp == NULL)
          {
            free (p);
            return IDNA_MALLOC_ERROR;
          }
        p = newp;

        if (flags & IDNA_ALLOW_UNASSIGNED)
          rc = stringprep_nameprep (p, len);
        else
          rc = stringprep_nameprep_no_unassigned (p, len);
      }
    while (rc == STRINGPREP_TOO_SMALL_BUFFER);

    if (rc != STRINGPREP_OK)
      {
        free (p);
        return IDNA_STRINGPREP_ERROR;
      }

    src = stringprep_utf8_to_ucs4 (p, -1, NULL);

    free (p);
  }

step3:
  /*
   * 3. If the UseSTD3ASCIIRules flag is set, then perform these checks:
   *
   * (a) Verify the absence of non-LDH ASCII code points; that is,
   * the absence of 0..2C, 2E..2F, 3A..40, 5B..60, and 7B..7F.
   *
   * (b) Verify the absence of leading and trailing hyphen-minus;
   * that is, the absence of U+002D at the beginning and end of
   * the sequence.
   */

  if (flags & IDNA_USE_STD3_ASCII_RULES)
    {
      size_t i;

      for (i = 0; src[i]; i++)
        if (src[i] <= 0x2C || src[i] == 0x2E || src[i] == 0x2F ||
            (src[i] >= 0x3A && src[i] <= 0x40) ||
            (src[i] >= 0x5B && src[i] <= 0x60) ||
            (src[i] >= 0x7B && src[i] <= 0x7F))
          {
            free (src);
            return IDNA_CONTAINS_NON_LDH;
          }

      if (src[0] == 0x002D || (i > 0 && src[i - 1] == 0x002D))
        {
          free (src);
          return IDNA_CONTAINS_MINUS;
        }
    }

  /*
   * 4. If all code points in the sequence are in the ASCII range
   * (0..7F), then skip to step 8.
   */

  {
    size_t i;
    int inasciirange;

    inasciirange = 1;
    for (i = 0; src[i]; i++)
      {
        if (src[i] > 0x7F)
          inasciirange = 0;
        /* copy string to output buffer if we are about to skip to step8 */
        if (i < 64)
          out[i] = src[i];
      }
    if (i < 64)
      out[i] = '\0';
    if (inasciirange)
      goto step8;
  }

  /*
   * 5. Verify that the sequence does NOT begin with the ACE prefix.
   *
   */

  {
    size_t i;
    int match;

    match = 1;
    for (i = 0; match && i < strlen (IDNA_ACE_PREFIX); i++)
      if (((uint32_t) IDNA_ACE_PREFIX[i] & 0xFF) != src[i])
        match = 0;
    if (match)
      {
        free (src);
        return IDNA_CONTAINS_ACE_PREFIX;
      }
  }

  /*
   * 6. Encode the sequence using the encoding algorithm in [PUNYCODE]
   * and fail if there is an error.
   */
  for (len = 0; src[len]; len++)
    ;
  src[len] = '\0';
  outlen = 63 - strlen (IDNA_ACE_PREFIX);
  rc = punycode_encode (len, src, NULL,
                        &outlen, &out[strlen (IDNA_ACE_PREFIX)]);
  if (rc != PUNYCODE_SUCCESS)
    {
      free (src);
      return IDNA_PUNYCODE_ERROR;
    }
  out[strlen (IDNA_ACE_PREFIX) + outlen] = '\0';

  /*
   * 7. Prepend the ACE prefix.
   */

  memcpy (out, IDNA_ACE_PREFIX, strlen (IDNA_ACE_PREFIX));

  /*
   * 8. Verify that the number of code points is in the range 1 to 63
   * inclusive (0 is excluded).
   */

step8:
  free (src);
  if (strlen (out) < 1 || strlen (out) > 63)
    return IDNA_INVALID_LENGTH;

  return IDNA_SUCCESS;
}

/* ToUnicode().  May realloc() utf8in.  Will free utf8in unconditionally. */
static int
idna_to_unicode_internal (char *utf8in,
                          uint32_t * out, size_t * outlen, int flags)
{
  int rc;
  char tmpout[64];
  size_t utf8len = strlen (utf8in) + 1;
  size_t addlen = 0;

  /*
   * ToUnicode consists of the following steps:
   *
   * 1. If the sequence contains any code points outside the ASCII range
   * (0..7F) then proceed to step 2, otherwise skip to step 3.
   */

  {
    size_t i;
    int inasciirange;

    inasciirange = 1;
    for (i = 0; utf8in[i]; i++)
      if (utf8in[i] & ~0x7F)
        inasciirange = 0;
    if (inasciirange)
      goto step3;
  }

  /*
   * 2. Perform the steps specified in [NAMEPREP] and fail if there is an
   * error. (If step 3 of ToASCII is also performed here, it will not
   * affect the overall behavior of ToUnicode, but it is not
   * necessary.) The AllowUnassigned flag is used in [NAMEPREP].
   */
  do
    {
      char *newp = realloc (utf8in, utf8len + addlen);
      if (newp == NULL)
        {
          free (utf8in);
          return IDNA_MALLOC_ERROR;
        }
      utf8in = newp;
      if (flags & IDNA_ALLOW_UNASSIGNED)
        rc = stringprep_nameprep (utf8in, utf8len + addlen);
      else
        rc = stringprep_nameprep_no_unassigned (utf8in, utf8len + addlen);
      addlen += 1;
    }
  while (rc == STRINGPREP_TOO_SMALL_BUFFER);

  if (rc != STRINGPREP_OK)
    {
      free (utf8in);
      return IDNA_STRINGPREP_ERROR;
    }

  /* 3. Verify that the sequence begins with the ACE prefix, and save a
   * copy of the sequence.
   */

step3:
  if (memcmp (IDNA_ACE_PREFIX, utf8in, strlen (IDNA_ACE_PREFIX)) != 0)
    {
      free (utf8in);
      return IDNA_NO_ACE_PREFIX;
    }

  /* 4. Remove the ACE prefix.
   */

  memmove (utf8in, &utf8in[strlen (IDNA_ACE_PREFIX)],
           strlen (utf8in) - strlen (IDNA_ACE_PREFIX) + 1);

  /* 5. Decode the sequence using the decoding algorithm in [PUNYCODE]
   * and fail if there is an error. Save a copy of the result of
   * this step.
   */

  (*outlen)--;                  /* reserve one for the zero */

  rc = punycode_decode (strlen (utf8in), utf8in, outlen, out, NULL);
  if (rc != PUNYCODE_SUCCESS)
    {
      free (utf8in);
      return IDNA_PUNYCODE_ERROR;
    }

  out[*outlen] = 0;             /* add zero */

  /* 6. Apply ToASCII.
   */

  rc = idna_to_ascii_4i (out, *outlen, tmpout, flags);
  if (rc != IDNA_SUCCESS)
    {
      free (utf8in);
      return rc;
    }

  /* 7. Verify that the result of step 6 matches the saved copy from
   * step 3, using a case-insensitive ASCII comparison.
   */

  if (strcasecmp (utf8in, tmpout + strlen (IDNA_ACE_PREFIX)) != 0)
    {
      free (utf8in);
      return IDNA_ROUNDTRIP_VERIFY_ERROR;
    }

  /* 8. Return the saved copy from step 5.
   */

  free (utf8in);
  return IDNA_SUCCESS;
}

int
idna_to_unicode_44i (const uint32_t * in, size_t inlen,
                     uint32_t * out, size_t * outlen, int flags)
{
  int rc;
  size_t outlensave = *outlen;
  char *p;

  p = stringprep_ucs4_to_utf8 (in, inlen, NULL, NULL);
  if (p == NULL)
    return IDNA_MALLOC_ERROR;

  rc = idna_to_unicode_internal (p, out, outlen, flags);
  if (rc != IDNA_SUCCESS)
    {
      memcpy (out, in, sizeof (in[0]) * (inlen < outlensave ?
                                         inlen : outlensave));
      *outlen = inlen;
    }

  /* p is freed in idna_to_unicode_internal.  */

  return rc;
}

/* Wrappers that handle several labels */

int
idna_to_ascii_4z (const uint32_t * input, char **output, int flags)
{
  const uint32_t *start = input;
  const uint32_t *end = input;
  char buf[64];
  char *out = NULL;
  int rc;

  /* 1) Whenever dots are used as label separators, the following
     characters MUST be recognized as dots: U+002E (full stop),
     U+3002 (ideographic full stop), U+FF0E (fullwidth full stop),
     U+FF61 (halfwidth ideographic full stop). */

  if (input[0] == 0)
    {
      /* Handle implicit zero-length root label. */
      *output = malloc (1);
      if (!*output)
        return IDNA_MALLOC_ERROR;
      strcpy (*output, "");
      return IDNA_SUCCESS;
    }

  if (DOTP (input[0]) && input[1] == 0)
    {
      /* Handle explicit zero-length root label. */
      *output = malloc (2);
      if (!*output)
        return IDNA_MALLOC_ERROR;
      strcpy (*output, ".");
      return IDNA_SUCCESS;
    }

  *output = NULL;
  do
    {
      end = start;

      for (; *end && !DOTP (*end); end++)
        ;

      if (*end == '\0' && start == end)
        {
          /* Handle explicit zero-length root label. */
          buf[0] = '\0';
        }
      else
        {
          rc = idna_to_ascii_4i (start, end - start, buf, flags);
          if (rc != IDNA_SUCCESS)
            return rc;
        }

      if (out)
        {
          char *newp = realloc (out, strlen (out) + 1 + strlen (buf) + 1);
          if (!newp)
            {
              free (out);
              return IDNA_MALLOC_ERROR;
            }
          out = newp;
          strcat (out, ".");
          strcat (out, buf);
        }
      else
        {
          out = (char *) malloc (strlen (buf) + 1);
          if (!out)
            return IDNA_MALLOC_ERROR;
          strcpy (out, buf);
        }

      start = end + 1;
    }
  while (*end);

  *output = out;

  return IDNA_SUCCESS;
}

int
idna_to_ascii_8z (const char *input, char **output, int flags)
{
  uint32_t *ucs4;
  size_t ucs4len;
  int rc;

  ucs4 = stringprep_utf8_to_ucs4 (input, -1, &ucs4len);
  if (!ucs4)
    return IDNA_ICONV_ERROR;

  rc = idna_to_ascii_4z (ucs4, output, flags);

  free (ucs4);

  return rc;

}

int
idna_to_ascii_lz (const char *input, char **output, int flags)
{
  char *utf8;
  int rc;

  utf8 = stringprep_locale_to_utf8 (input);
  if (!utf8)
    return IDNA_ICONV_ERROR;

  rc = idna_to_ascii_8z (utf8, output, flags);

  free (utf8);

  return rc;
}

int
idna_to_unicode_4z4z (const uint32_t * input, uint32_t ** output, int flags)
{
  const uint32_t *start = input;
  const uint32_t *end = input;
  uint32_t *buf;
  size_t buflen;
  uint32_t *out = NULL;
  size_t outlen = 0;
  int rc;

  *output = NULL;

  do
    {
      end = start;

      for (; *end && !DOTP (*end); end++)
        ;

      buflen = end - start;
      buf = malloc (sizeof (buf[0]) * (buflen + 1));
      if (!buf)
        return IDNA_MALLOC_ERROR;

      rc = idna_to_unicode_44i (start, end - start, buf, &buflen, flags);
      /* don't check rc as per specification! */

      if (out)
        {
          uint32_t *newp = realloc (out,
                                    sizeof (out[0])
                                    * (outlen + 1 + buflen + 1));
          if (!newp)
            {
              free (buf);
              free (out);
              return IDNA_MALLOC_ERROR;
            }
          out = newp;
          out[outlen++] = 0x002E;       /* '.' (full stop) */
          memcpy (out + outlen, buf, sizeof (buf[0]) * buflen);
          outlen += buflen;
          out[outlen] = 0x0;
          free (buf);
        }
      else
        {
          out = buf;
          outlen = buflen;
          out[outlen] = 0x0;
        }

      start = end + 1;
    }
  while (*end);

  *output = out;

  return IDNA_SUCCESS;
}

int
idna_to_unicode_8z4z (const char *input, uint32_t ** output, int flags)
{
  uint32_t *ucs4;
  size_t ucs4len;
  int rc;

  ucs4 = stringprep_utf8_to_ucs4 (input, -1, &ucs4len);
  if (!ucs4)
    return IDNA_ICONV_ERROR;

  rc = idna_to_unicode_4z4z (ucs4, output, flags);
  free (ucs4);

  return rc;
}

int
idna_to_unicode_8z8z (const char *input, char **output, int flags)
{
  uint32_t *ucs4;
  int rc;

  rc = idna_to_unicode_8z4z (input, &ucs4, flags);
  *output = stringprep_ucs4_to_utf8 (ucs4, -1, NULL, NULL);
  free (ucs4);

  if (!*output)
    return IDNA_ICONV_ERROR;

  return rc;
}

int
idna_to_unicode_8zlz (const char *input, char **output, int flags)
{
  char *utf8;
  int rc;

  rc = idna_to_unicode_8z8z (input, &utf8, flags);
  *output = stringprep_utf8_to_locale (utf8);
  free (utf8);

  if (!*output)
    return IDNA_ICONV_ERROR;

  return rc;
}

int
idna_to_unicode_lzlz (const char *input, char **output, int flags)
{
  char *utf8;
  int rc;

  utf8 = stringprep_locale_to_utf8 (input);
  if (!utf8)
    return IDNA_ICONV_ERROR;

  rc = idna_to_unicode_8zlz (utf8, output, flags);
  free (utf8);

  return rc;
}

---