NeoMutt  2021-10-29-33-g41675a
Teaching an old dog new tricks
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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"
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Go to the source code of this file.

Macros

#define IDN2_SKIP_LIBIDN_COMPAT
 

Functions

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

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

◆ 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
userUsername
domainDomain
flagsFlags, e.g. MI_MAY_BE_IRREVERSIBLE
Return values
ptrNewly allocated local email address
NULLError 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.

145 {
146  char *mailbox = NULL;
147  char *reversed_user = NULL, *reversed_domain = NULL;
148  char *tmp = NULL;
149 
150  char *local_user = mutt_str_dup(user);
151  char *local_domain = mutt_str_dup(domain);
152 
153 #ifdef HAVE_LIBIDN
154  bool is_idn_encoded = check_idn(local_domain);
155  const bool c_idn_decode = cs_subset_bool(NeoMutt->sub, "idn_decode");
156  if (is_idn_encoded && c_idn_decode)
157  {
158 #if (IDN_VERSION == 2)
159  if (idn2_to_unicode_8z8z(local_domain, &tmp, IDN2_ALLOW_UNASSIGNED) != IDN2_OK)
160 #else
161  if (idna_to_unicode_8z8z(local_domain, &tmp, IDNA_ALLOW_UNASSIGNED) != IDNA_SUCCESS)
162 #endif
163  {
164  goto cleanup;
165  }
166  mutt_str_replace(&local_domain, tmp);
167  FREE(&tmp);
168  }
169 #endif /* HAVE_LIBIDN */
170 
171  /* we don't want charset-hook effects, so we set flags to 0 */
172  const char *const c_charset = cs_subset_string(NeoMutt->sub, "charset");
173  if (mutt_ch_convert_string(&local_user, "utf-8", c_charset, MUTT_ICONV_NO_FLAGS) != 0)
174  goto cleanup;
175 
176  if (mutt_ch_convert_string(&local_domain, "utf-8", c_charset, MUTT_ICONV_NO_FLAGS) != 0)
177  goto cleanup;
178 
179  /* make sure that we can convert back and come out with the same
180  * user and domain name. */
181  if ((flags & MI_MAY_BE_IRREVERSIBLE) == 0)
182  {
183  reversed_user = mutt_str_dup(local_user);
184 
185  if (mutt_ch_convert_string(&reversed_user, c_charset, "utf-8", MUTT_ICONV_NO_FLAGS) != 0)
186  {
187  mutt_debug(LL_DEBUG1, "Not reversible. Charset conv to utf-8 failed for user = '%s'\n",
188  reversed_user);
189  goto cleanup;
190  }
191 
192  if (!mutt_istr_equal(user, reversed_user))
193  {
194  mutt_debug(LL_DEBUG1, "#1 Not reversible. orig = '%s', reversed = '%s'\n",
195  user, reversed_user);
196  goto cleanup;
197  }
198 
199  reversed_domain = mutt_str_dup(local_domain);
200 
201  if (mutt_ch_convert_string(&reversed_domain, c_charset, "utf-8", MUTT_ICONV_NO_FLAGS) != 0)
202  {
203  mutt_debug(LL_DEBUG1, "Not reversible. Charset conv to utf-8 failed for domain = '%s'\n",
204  reversed_domain);
205  goto cleanup;
206  }
207 
208 #ifdef HAVE_LIBIDN
209  /* If the original domain was UTF-8, idna encoding here could
210  * produce a non-matching domain! Thus we only want to do the
211  * idna_to_ascii_8z() if the original domain was IDNA encoded. */
212  if (is_idn_encoded && c_idn_decode)
213  {
214 #if (IDN_VERSION == 2)
215  if (idn2_to_ascii_8z(reversed_domain, &tmp,
216  IDN2_ALLOW_UNASSIGNED | IDN2_NFC_INPUT | IDN2_NONTRANSITIONAL) != IDN2_OK)
217 #else
218  if (idna_to_ascii_8z(reversed_domain, &tmp, IDNA_ALLOW_UNASSIGNED) != IDNA_SUCCESS)
219 #endif
220  {
221  mutt_debug(LL_DEBUG1, "Not reversible. idna_to_ascii_8z failed for domain = '%s'\n",
222  reversed_domain);
223  goto cleanup;
224  }
225  mutt_str_replace(&reversed_domain, tmp);
226  }
227 #endif /* HAVE_LIBIDN */
228 
229  if (!mutt_istr_equal(domain, reversed_domain))
230  {
231  mutt_debug(LL_DEBUG1, "#2 Not reversible. orig = '%s', reversed = '%s'\n",
232  domain, reversed_domain);
233  goto cleanup;
234  }
235  }
236 
237  mailbox = mutt_mem_malloc(mutt_str_len(local_user) + mutt_str_len(local_domain) + 2);
238  sprintf(mailbox, "%s@%s", NONULL(local_user), NONULL(local_domain));
239 
240 cleanup:
241  FREE(&local_user);
242  FREE(&local_domain);
243  FREE(&tmp);
244  FREE(&reversed_domain);
245  FREE(&reversed_user);
246 
247  return mailbox;
248 }
#define mutt_debug(LEVEL,...)
Definition: logging.h:84
const char * cs_subset_string(const struct ConfigSubset *sub, const char *name)
Get a string config item by name.
Definition: helpers.c:317
bool cs_subset_bool(const struct ConfigSubset *sub, const char *name)
Get a boolean config item by name.
Definition: helpers.c:73
#define MI_MAY_BE_IRREVERSIBLE
Definition: idna2.h:30
@ LL_DEBUG1
Log at debug level 1.
Definition: logging.h:40
void * mutt_mem_malloc(size_t size)
Allocate memory on the heap.
Definition: memory.c:90
#define FREE(x)
Definition: memory.h:40
int mutt_ch_convert_string(char **ps, const char *from, const char *to, uint8_t flags)
Convert a string between encodings.
Definition: charset.c:765
#define MUTT_ICONV_NO_FLAGS
No flags are set.
Definition: charset.h:71
bool mutt_istr_equal(const char *a, const char *b)
Compare two strings, ignoring case.
Definition: string.c:727
char * mutt_str_dup(const char *str)
Copy a string, safely.
Definition: string.c:181
size_t mutt_str_len(const char *a)
Calculate the length of a string, safely.
Definition: string.c:475
char * mutt_str_replace(char **p, const char *s)
Replace one string with another.
Definition: string.c:257
#define NONULL(x)
Definition: string2.h:37
Container for Accounts, Notifications.
Definition: neomutt.h:37
struct ConfigSubset * sub
Inherited config items.
Definition: neomutt.h:39
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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
userUsername
domainDomain
Return values
ptrNewly allocated Punycode email address
NULLError 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.

265 {
266  char *mailbox = NULL;
267  char *tmp = NULL;
268 
269  char *intl_user = mutt_str_dup(user);
270  char *intl_domain = mutt_str_dup(domain);
271 
272  /* we don't want charset-hook effects, so we set flags to 0 */
273  const char *const c_charset = cs_subset_string(NeoMutt->sub, "charset");
274  if (mutt_ch_convert_string(&intl_user, c_charset, "utf-8", MUTT_ICONV_NO_FLAGS) != 0)
275  goto cleanup;
276 
277  if (mutt_ch_convert_string(&intl_domain, c_charset, "utf-8", MUTT_ICONV_NO_FLAGS) != 0)
278  goto cleanup;
279 
280 #ifdef HAVE_LIBIDN
281  const bool c_idn_encode = cs_subset_bool(NeoMutt->sub, "idn_encode");
282  if (c_idn_encode)
283  {
284 #if (IDN_VERSION == 2)
285  if (idn2_to_ascii_8z(intl_domain, &tmp,
286  IDN2_ALLOW_UNASSIGNED | IDN2_NFC_INPUT | IDN2_NONTRANSITIONAL) != IDN2_OK)
287 #else
288  if (idna_to_ascii_8z(intl_domain, &tmp, IDNA_ALLOW_UNASSIGNED) != IDNA_SUCCESS)
289 #endif
290  {
291  goto cleanup;
292  }
293  mutt_str_replace(&intl_domain, tmp);
294  }
295 #endif /* HAVE_LIBIDN */
296 
297  mailbox = mutt_mem_malloc(mutt_str_len(intl_user) + mutt_str_len(intl_domain) + 2);
298  sprintf(mailbox, "%s@%s", NONULL(intl_user), NONULL(intl_domain));
299 
300 cleanup:
301  FREE(&intl_user);
302  FREE(&intl_domain);
303  FREE(&tmp);
304 
305  return mailbox;
306 }
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◆ mutt_idna_print_version()

const char* mutt_idna_print_version ( void  )

Create an IDN version string.

Return values
ptrVersion string
Note
This is a static string and must not be freed.

Definition at line 314 of file idna.c.

315 {
316  static char vstring[256];
317 
318 #ifdef HAVE_LIBIDN
319 #if (IDN_VERSION == 2)
320  snprintf(vstring, sizeof(vstring), "libidn2: %s (compiled with %s)",
321  idn2_check_version(NULL), IDN2_VERSION);
322 #elif (IDN_VERSION == 1)
323  snprintf(vstring, sizeof(vstring), "libidn: %s (compiled with %s)",
324  stringprep_check_version(NULL), STRINGPREP_VERSION);
325 #endif
326 #endif /* HAVE_LIBIDN */
327 
328  return vstring;
329 }
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