idna.c File Reference

Handling of international domain names. More...

#include "config.h"
#include <stdint.h>
#include <stdio.h>
#include "mutt/lib.h"
#include "config/lib.h"
#include "core/lib.h"
#include "idna2.h"
#include <stdbool.h>
#include <string.h>

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Macros
#define	IDN2_SKIP_LIBIDN_COMPAT

Functions
static bool	check_idn (char *domain)
	Is domain in Punycode? More...
int	mutt_idna_to_ascii_lz (const char *input, char **output, uint8_t flags)
	Convert a domain to Punycode. More...
char *	mutt_idna_intl_to_local (const char *user, const char *domain, uint8_t flags)
	Convert an email's domain from Punycode. More...
char *	mutt_idna_local_to_intl (const char *user, const char *domain)
	Convert an email's domain to Punycode. More...
const char *	mutt_idna_print_version (void)
	Create an IDN version string. More...

Detailed Description

Handling of international domain names.

Authors

• Thomas Roessler

Copyright

This program is free software: you can redistribute it and/or modify it under the terms of 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.

This program 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 a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.

Definition in file idna.c.

Macro Definition Documentation

IDN2_SKIP_LIBIDN_COMPAT

#define IDN2_SKIP_LIBIDN_COMPAT

Definition at line 45 of file idna.c.

Function Documentation

check_idn()

static bool check_idn ( char *  domain )

static

Is domain in Punycode?

Parameters

domain

Domain to test

Return values

true	At least one part of domain is in Punycode

Definition at line 84 of file idna.c.

{
  if (!domain)
    return false;
 
  if (mutt_istr_startswith(domain, "xn--"))
    return true;
 
  while ((domain = strchr(domain, '.')))
  {
    if (mutt_istr_startswith(++domain, "xn--"))
      return true;
  }
 
  return false;
}

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mutt_idna_to_ascii_lz()

int mutt_idna_to_ascii_lz	(	const char *	input,
		char **	output,
		uint8_t	flags
	)

Convert a domain to Punycode.

Parameters

[in]	input	Domain
[out]	output	Result
[in]	flags	Flags, e.g. IDNA_ALLOW_UNASSIGNED

Return values

0	Success
>0	Failure, error code

Convert a domain from the current locale to Punycode.

Note

The caller must free output

Definition at line 113 of file idna.c.

{
  if (!input || !output)
    return 1;
 
#if (IDN_VERSION == 2)
  return idn2_to_ascii_8z(input, output, flags | IDN2_NFC_INPUT | IDN2_NONTRANSITIONAL);
#else
  return idna_to_ascii_lz(input, output, flags);
#endif
}

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mutt_idna_intl_to_local()

char * mutt_idna_intl_to_local	(	const char *	user,
		const char *	domain,
		uint8_t	flags
	)

Convert an email's domain from Punycode.

Parameters

user	Username
domain	Domain
flags	Flags, e.g. MI_MAY_BE_IRREVERSIBLE

Return values

ptr	Newly allocated local email address
NULL	Error in conversion

If $idn_decode is set, then the domain will be converted from Punycode. For example, "xn--ls8h.la" becomes the emoji domain: ":poop:.la" Then the user and domain are changed from 'utf-8' to the encoding in $charset.

If the flag MI_MAY_BE_IRREVERSIBLE is NOT given, then the results will be checked to make sure that the transformation is "undo-able".

Note

The caller must free the returned string.

Definition at line 144 of file idna.c.

{
  char *mailbox = NULL;
  char *reversed_user = NULL, *reversed_domain = NULL;
  char *tmp = NULL;
 
  char *local_user = mutt_str_dup(user);
  char *local_domain = mutt_str_dup(domain);
 
#ifdef HAVE_LIBIDN
  bool is_idn_encoded = check_idn(local_domain);
  const bool c_idn_decode = cs_subset_bool(NeoMutt->sub, "idn_decode");
  if (is_idn_encoded && c_idn_decode)
  {
#if (IDN_VERSION == 2)
    if (idn2_to_unicode_8z8z(local_domain, &tmp, IDN2_ALLOW_UNASSIGNED) != IDN2_OK)
#else
    if (idna_to_unicode_8z8z(local_domain, &tmp, IDNA_ALLOW_UNASSIGNED) != IDNA_SUCCESS)
#endif
    {
      goto cleanup;
    }
    mutt_str_replace(&local_domain, tmp);
    FREE(&tmp);
  }
#endif /* HAVE_LIBIDN */
 
  /* we don't want charset-hook effects, so we set flags to 0 */
  const char *const c_charset = cs_subset_string(NeoMutt->sub, "charset");
  if (mutt_ch_convert_string(&local_user, "utf-8", c_charset, MUTT_ICONV_NO_FLAGS) != 0)
    goto cleanup;
 
  if (mutt_ch_convert_string(&local_domain, "utf-8", c_charset, MUTT_ICONV_NO_FLAGS) != 0)
    goto cleanup;
 
  /* make sure that we can convert back and come out with the same
   * user and domain name.  */
  if ((flags & MI_MAY_BE_IRREVERSIBLE) == 0)
  {
    reversed_user = mutt_str_dup(local_user);
 
    if (mutt_ch_convert_string(&reversed_user, c_charset, "utf-8", MUTT_ICONV_NO_FLAGS) != 0)
    {
      mutt_debug(LL_DEBUG1, "Not reversible. Charset conv to utf-8 failed for user = '%s'\n",
                 reversed_user);
      goto cleanup;
    }
 
    if (!mutt_istr_equal(user, reversed_user))
    {
      mutt_debug(LL_DEBUG1, "#1 Not reversible. orig = '%s', reversed = '%s'\n",
                 user, reversed_user);
      goto cleanup;
    }
 
    reversed_domain = mutt_str_dup(local_domain);
 
    if (mutt_ch_convert_string(&reversed_domain, c_charset, "utf-8", MUTT_ICONV_NO_FLAGS) != 0)
    {
      mutt_debug(LL_DEBUG1, "Not reversible. Charset conv to utf-8 failed for domain = '%s'\n",
                 reversed_domain);
      goto cleanup;
    }
 
#ifdef HAVE_LIBIDN
    /* If the original domain was UTF-8, idna encoding here could
     * produce a non-matching domain!  Thus we only want to do the
     * idna_to_ascii_8z() if the original domain was IDNA encoded.  */
    if (is_idn_encoded && c_idn_decode)
    {
#if (IDN_VERSION == 2)
      if (idn2_to_ascii_8z(reversed_domain, &tmp,
                           IDN2_ALLOW_UNASSIGNED | IDN2_NFC_INPUT | IDN2_NONTRANSITIONAL) != IDN2_OK)
#else
      if (idna_to_ascii_8z(reversed_domain, &tmp, IDNA_ALLOW_UNASSIGNED) != IDNA_SUCCESS)
#endif
      {
        mutt_debug(LL_DEBUG1, "Not reversible. idna_to_ascii_8z failed for domain = '%s'\n",
                   reversed_domain);
        goto cleanup;
      }
      mutt_str_replace(&reversed_domain, tmp);
    }
#endif /* HAVE_LIBIDN */
 
    if (!mutt_istr_equal(domain, reversed_domain))
    {
      mutt_debug(LL_DEBUG1, "#2 Not reversible. orig = '%s', reversed = '%s'\n",
                 domain, reversed_domain);
      goto cleanup;
    }
  }
 
  mailbox = mutt_mem_malloc(mutt_str_len(local_user) + mutt_str_len(local_domain) + 2);
  sprintf(mailbox, "%s@%s", NONULL(local_user), NONULL(local_domain));
 
cleanup:
  FREE(&local_user);
  FREE(&local_domain);
  FREE(&tmp);
  FREE(&reversed_domain);
  FREE(&reversed_user);
 
  return mailbox;
}

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mutt_idna_local_to_intl()

char * mutt_idna_local_to_intl	(	const char *	user,
		const char *	domain
	)

Convert an email's domain to Punycode.

Parameters

user	Username
domain	Domain

Return values

ptr	Newly allocated Punycode email address
NULL	Error in conversion

The user and domain are assumed to be encoded according to $charset. They are converted to 'utf-8'. If $idn_encode is set, then the domain will be converted to Punycode. For example, the emoji domain: ":poop:.la" becomes "xn--ls8h.la"

Note

The caller must free the returned string.

Definition at line 264 of file idna.c.

{
  char *mailbox = NULL;
  char *tmp = NULL;
 
  char *intl_user = mutt_str_dup(user);
  char *intl_domain = mutt_str_dup(domain);
 
  /* we don't want charset-hook effects, so we set flags to 0 */
  const char *const c_charset = cs_subset_string(NeoMutt->sub, "charset");
  if (mutt_ch_convert_string(&intl_user, c_charset, "utf-8", MUTT_ICONV_NO_FLAGS) != 0)
    goto cleanup;
 
  if (mutt_ch_convert_string(&intl_domain, c_charset, "utf-8", MUTT_ICONV_NO_FLAGS) != 0)
    goto cleanup;
 
#ifdef HAVE_LIBIDN
  const bool c_idn_encode = cs_subset_bool(NeoMutt->sub, "idn_encode");
  if (c_idn_encode)
  {
#if (IDN_VERSION == 2)
    if (idn2_to_ascii_8z(intl_domain, &tmp,
                         IDN2_ALLOW_UNASSIGNED | IDN2_NFC_INPUT | IDN2_NONTRANSITIONAL) != IDN2_OK)
#else
    if (idna_to_ascii_8z(intl_domain, &tmp, IDNA_ALLOW_UNASSIGNED) != IDNA_SUCCESS)
#endif
    {
      goto cleanup;
    }
    mutt_str_replace(&intl_domain, tmp);
  }
#endif /* HAVE_LIBIDN */
 
  mailbox = mutt_mem_malloc(mutt_str_len(intl_user) + mutt_str_len(intl_domain) + 2);
  sprintf(mailbox, "%s@%s", NONULL(intl_user), NONULL(intl_domain));
 
cleanup:
  FREE(&intl_user);
  FREE(&intl_domain);
  FREE(&tmp);
 
  return mailbox;
}

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mutt_idna_print_version()

const char * mutt_idna_print_version

(

void

)

Create an IDN version string.

Return values

ptr	Version string

Note

This is a static string and must not be freed.

Definition at line 314 of file idna.c.

{
  static char vstring[256];
 
#ifdef HAVE_LIBIDN
#if (IDN_VERSION == 2)
  snprintf(vstring, sizeof(vstring), "libidn2: %s (compiled with %s)",
           idn2_check_version(NULL), IDN2_VERSION);
#elif (IDN_VERSION == 1)
  snprintf(vstring, sizeof(vstring), "libidn: %s (compiled with %s)",
           stringprep_check_version(NULL), STRINGPREP_VERSION);
#endif
#endif /* HAVE_LIBIDN */
 
  return vstring;
}

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