1 /*
2  * Copyright (c) 2020 Martijn van Duren <martijn@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <ctype.h>
18 #include <errno.h>
19 #include <stddef.h>
20 #include <string.h>
21 #include <strings.h>
22 
23 #include "mheader.h"
24 
25 #include <stdio.h>
26 char *
27 osmtpd_mheader_skip_sp(char *ptr, int optional)
28 {
29 	if (ptr[0] == 0x20)
30 		return ptr + 1;
31 	return optional ? ptr : NULL;
32 }
33 
34 char *
35 osmtpd_mheader_skip_htab(char *ptr, int optional)
36 {
37 	if (ptr[0] == 0x9)
38 		return ptr + 1;
39 	return optional ? ptr : NULL;
40 }
41 
42 char *
43 osmtpd_mheader_skip_wsp(char *ptr, int optional)
44 {
45 	char *start = ptr;
46 
47 	if ((ptr = osmtpd_mheader_skip_sp(start, 0)) != NULL ||
48 	    (ptr = osmtpd_mheader_skip_htab(start, 0)) != NULL)
49 		return ptr;
50 	return optional ? ptr : NULL;
51 }
52 
53 char *
54 osmtpd_mheader_skip_crlf(char *ptr, int optional)
55 {
56 	if (ptr[0] == 13 && ptr[1] == 10)
57 		return ptr + 2;
58 	return optional ? ptr : NULL;
59 }
60 
61 char *
62 osmtpd_mheader_skip_vchar(char *ptr, int optional)
63 {
64 	if (ptr[0] >= 0x21 && ptr[0] <= 0x7e)
65 		return ptr + 1;
66 	return optional ? ptr : NULL;
67 }
68 
69 char *
70 osmtpd_mheader_skip_lf(char *ptr, int optional)
71 {
72 	if (ptr[0] == 0xa)
73 		return ptr + 1;
74 	return optional ? ptr : NULL;
75 }
76 
77 char *
78 osmtpd_mheader_skip_cr(char *ptr, int optional)
79 {
80 	if (ptr[0] == 0xd)
81 		return ptr + 1;
82 	return optional ? ptr : NULL;
83 }
84 
85 char *
86 osmtpd_mheader_skip_alpha(char *ptr, int optional)
87 {
88 	if ((ptr[0] >= 0x41 && ptr[0] <= 0x5a) ||
89 	    (ptr[0] >= 0x61 && ptr[0] <= 0x7a))
90 		return ptr + 1;
91 	return optional ? ptr : NULL;
92 }
93 
94 char *
95 osmtpd_mheader_skip_digit(char *ptr, int optional)
96 {
97 	if (ptr[0] >= 0x30 && ptr[0] <= 0x39)
98 		return ptr + 1;
99 	return optional ? ptr : NULL;
100 }
101 
102 char *
103 osmtpd_mheader_skip_dquote(char *ptr, int optional)
104 {
105 	if (ptr[0] == 0x22)
106 		return ptr + 1;
107 	return optional ? ptr : NULL;
108 }
109 
110 char *
111 osmtpd_mheader_skip_obs_fws(char *ptr, int optional)
112 {
113 	char *start = ptr, *prev;
114 
115 	if ((ptr = osmtpd_mheader_skip_wsp(ptr, 0)) == NULL)
116 		return optional ? start : NULL;
117 	prev = ptr;
118 	while ((ptr = osmtpd_mheader_skip_wsp(ptr, 0)) != NULL)
119 		prev = ptr;
120 
121 	ptr = prev;
122 	while (1) {
123 		if ((ptr = osmtpd_mheader_skip_crlf(ptr, 0)) == NULL)
124 			return prev;
125 		if ((ptr = osmtpd_mheader_skip_wsp(ptr, 0)) == NULL)
126 			return prev;
127 		prev = ptr;
128 		while ((ptr = osmtpd_mheader_skip_wsp(ptr, 0)) != NULL)
129 			prev = ptr;
130 		ptr = prev;
131 	}
132 }
133 
134 char *
135 osmtpd_mheader_skip_fws(char *ptr, int optional)
136 {
137 	char *start = ptr, *prev = ptr;
138 
139 	while ((ptr = osmtpd_mheader_skip_wsp(ptr, 0)) != NULL)
140 		prev = ptr;
141 	if ((ptr = osmtpd_mheader_skip_crlf(prev, 1)) == prev)
142 		ptr = start;
143 	if ((ptr = osmtpd_mheader_skip_wsp(ptr, 0)) == NULL)
144 		return osmtpd_mheader_skip_obs_fws(start, optional);
145 	prev = ptr;
146 	while ((ptr = osmtpd_mheader_skip_wsp(ptr, 0)) != NULL)
147 		prev = ptr;
148 	return prev;
149 }
150 
151 char *
152 osmtpd_mheader_skip_obs_no_ws_ctl(char *ptr, int optional)
153 {
154 	if ((ptr[0] >= 1 && ptr[0] <= 8) || ptr[0] == 11 || ptr[0] == 12 ||
155 	    (ptr[0] >= 14 && ptr[0] <= 31) || ptr[0] == 127)
156 		return ptr + 1;
157 	return optional ? ptr : NULL;
158 }
159 
160 char *
161 osmtpd_mheader_skip_obs_ctext(char *ptr, int optional)
162 {
163 	return osmtpd_mheader_skip_obs_no_ws_ctl(ptr, optional);
164 }
165 
166 char *
167 osmtpd_mheader_skip_ctext(char *ptr, int optional)
168 {
169 	char *start = ptr;
170 
171 	if ((ptr[0] >= 33 && ptr[0] <= 39) || (ptr[0] >= 42 && ptr[0] <= 91) ||
172 	    (ptr[0] >= 93 && ptr[0] <= 126))
173 		return ptr + 1;
174 	if ((ptr = osmtpd_mheader_skip_obs_ctext(ptr, 0)) != NULL)
175 		return ptr;
176 	return optional ? start : NULL;
177 }
178 
179 char *
180 osmtpd_mheader_skip_obs_qp(char *ptr, int optional)
181 {
182 	char *start = ptr;
183 
184 	if (ptr[0] == '\\' && (
185 	    (ptr = osmtpd_mheader_skip_obs_no_ws_ctl(start + 1, 0)) != NULL ||
186 	    (ptr = osmtpd_mheader_skip_lf(start + 1, 0)) != NULL ||
187 	    (ptr = osmtpd_mheader_skip_cr(start + 1, 0)) != NULL))
188 		return ptr;
189 	return optional ? start : NULL;
190 }
191 
192 char *
193 osmtpd_mheader_skip_quoted_pair(char *ptr, int optional)
194 {
195 	char *start = ptr;
196 
197 	if (ptr[0] == '\\' && (
198 	    (ptr = osmtpd_mheader_skip_vchar(start + 1, 0)) != NULL ||
199 	    (ptr = osmtpd_mheader_skip_wsp(start + 1, 0)) != NULL))
200 		return ptr;
201 	return osmtpd_mheader_skip_obs_qp(start, optional);
202 }
203 
204 char *
205 osmtpd_mheader_skip_ccontent(char *ptr, int optional)
206 {
207 	char *start = ptr;
208 
209 	if ((ptr = osmtpd_mheader_skip_ctext(ptr, 0)) != NULL)
210 		return ptr;
211 	if ((ptr = osmtpd_mheader_skip_quoted_pair(start, 0)) != NULL)
212 		return ptr;
213 	if ((ptr = osmtpd_mheader_skip_comment(start, 0)) != NULL)
214 		return ptr;
215 	return optional ? start : NULL;
216 }
217 
218 char *
219 osmtpd_mheader_skip_comment(char *ptr, int optional)
220 {
221 	char *start = ptr;
222 
223 	if (ptr++[0] != '(')
224 		return optional ? start : NULL;
225 	while (1) {
226 		ptr = osmtpd_mheader_skip_fws(ptr, 1);
227 		if (ptr[0] == ')')
228 			return ptr + 1;
229 		if ((ptr = osmtpd_mheader_skip_ccontent(ptr, 0)) == NULL)
230 			return optional ? start : NULL;
231 	}
232 }
233 
234 char *
235 osmtpd_mheader_skip_cfws(char *ptr, int optional)
236 {
237 	char *start = ptr, *prev;
238 
239 	while (1) {
240 		ptr = osmtpd_mheader_skip_fws(ptr, 1);
241 		prev = ptr;
242 		if ((ptr = osmtpd_mheader_skip_comment(ptr, 0)) == NULL) {
243 			ptr = prev;
244 			break;
245 		}
246 	}
247 	return ptr == start && !optional ? NULL : ptr;
248 }
249 
250 char *
251 osmtpd_mheader_skip_atext(char *ptr, int optional)
252 {
253 	char *start = ptr;
254 
255 	if ((ptr = osmtpd_mheader_skip_alpha(start, 0)) != NULL ||
256 	    (ptr = osmtpd_mheader_skip_digit(start, 0)) != NULL)
257 		return ptr;
258 	ptr = start;
259 	if (ptr[0] == '!' || ptr[0] == '#' || ptr[0] == '$' || ptr[0] == '%' ||
260 	    ptr[0] == '&' || ptr[0] == '\'' || ptr[0] == '*' || ptr[0] == '+' ||
261 	    ptr[0] == '-' || ptr[0] == '/' || ptr[0] == '=' || ptr[0] == '?' ||
262 	    ptr[0] == '^' || ptr[0] == '_' || ptr[0] == '`' || ptr[0] == '{' ||
263 	    ptr[0] == '|' || ptr[0] == '}' || ptr[0] == '~')
264 		return ptr + 1;
265 	return optional ? start : NULL;
266 }
267 
268 char *
269 osmtpd_mheader_skip_atom(char *ptr, int optional)
270 {
271 	char *start = ptr, *prev;
272 
273 	ptr = osmtpd_mheader_skip_cfws(ptr, 1);
274 	if ((ptr = osmtpd_mheader_skip_atext(ptr, 0)) == NULL)
275 		return optional ? start : NULL;
276 	do {
277 		prev = ptr;
278 		ptr = osmtpd_mheader_skip_atext(ptr, 1);
279 	} while (prev != ptr);
280 	return osmtpd_mheader_skip_cfws(ptr, 1);
281 }
282 
283 char *
284 osmtpd_mheader_skip_dot_atom_text(char *ptr, int optional)
285 {
286 	char *start = ptr, *prev;
287 
288 	if ((ptr = osmtpd_mheader_skip_atext(ptr, 0)) == NULL)
289 		return optional ? start : NULL;
290 	do {
291 		prev = ptr;
292 		ptr = osmtpd_mheader_skip_atext(ptr, 1);
293 	} while (ptr != prev);
294 
295 	while (ptr[0] == '.') {
296 		ptr++;
297 		if ((ptr = osmtpd_mheader_skip_atext(ptr, 0)) == NULL)
298 			return prev;
299 		do {
300 			prev = ptr;
301 			ptr = osmtpd_mheader_skip_atext(ptr, 1);
302 		} while (ptr != prev);
303 	}
304 	return ptr;
305 }
306 
307 char *
308 osmtpd_mheader_skip_dot_atom(char *ptr, int optional)
309 {
310 	char *start = ptr;
311 
312 	ptr = osmtpd_mheader_skip_cfws(ptr, 1);
313 	if ((ptr = osmtpd_mheader_skip_dot_atom_text(ptr, 0)) == NULL)
314 		return optional ? start : NULL;
315 	return osmtpd_mheader_skip_cfws(ptr, 1);
316 }
317 
318 
319 char *
320 osmtpd_mheader_skip_obs_qtext(char *ptr, int optional)
321 {
322 	return osmtpd_mheader_skip_obs_no_ws_ctl(ptr, optional);
323 }
324 
325 char *
326 osmtpd_mheader_skip_qtext(char *ptr, int optional)
327 {
328 	char *start = ptr;
329 
330 	if (ptr[0] == 33 || (ptr[0] >= 35 && ptr[0] <= 91) ||
331 	    (ptr[0] >= 93 && ptr[0] <= 126))
332 		return ptr + 1;
333 	if ((ptr = osmtpd_mheader_skip_obs_qtext(ptr, 0)) != NULL)
334 		return ptr;
335 	return optional ? start : NULL;
336 }
337 
338 char *
339 osmtpd_mheader_skip_qcontent(char *ptr, int optional)
340 {
341 	char *start = ptr;
342 
343 	if ((ptr = osmtpd_mheader_skip_qtext(ptr, 0)) != NULL)
344 		return ptr;
345 	return osmtpd_mheader_skip_quoted_pair(start, optional);
346 }
347 
348 char *
349 osmtpd_mheader_skip_quoted_string(char *ptr, int optional)
350 {
351 	char *start = ptr, *prev;
352 
353 	ptr = osmtpd_mheader_skip_cfws(ptr, 1);
354 	if ((ptr = osmtpd_mheader_skip_dquote(ptr, 0)) == NULL)
355 		return optional ? start : NULL;
356 	prev = ptr;
357 	while (1) {
358 		ptr = osmtpd_mheader_skip_fws(ptr, 1);
359 		if ((ptr = osmtpd_mheader_skip_qcontent(ptr, 0)) == NULL)
360 			break;
361 		prev = ptr;
362 	}
363 	if ((ptr = osmtpd_mheader_skip_dquote(prev, 0)) == NULL)
364 		return optional ? start : NULL;
365 	return osmtpd_mheader_skip_cfws(ptr, 1);
366 }
367 
368 char *
369 osmtpd_mheader_skip_word(char *ptr, int optional)
370 {
371 	char *start = ptr;
372 
373 	if ((ptr = osmtpd_mheader_skip_atom(ptr, 0)) != NULL)
374 		return ptr;
375 	return osmtpd_mheader_skip_quoted_string(start, optional);
376 }
377 
378 char *
379 osmtpd_mheader_skip_obs_phrase(char *ptr, int optional)
380 {
381 	char *start = ptr, *prev;
382 
383 	if ((ptr = osmtpd_mheader_skip_word(ptr, 0)) == NULL)
384 		return optional ? start : NULL;
385 	while (1) {
386 		prev = ptr;
387 		if ((ptr = osmtpd_mheader_skip_word(ptr, 0)) != NULL)
388 			continue;
389 		ptr = prev;
390 		if (ptr[0] == '.') {
391 			ptr++;
392 			continue;
393 		}
394 		if ((ptr = osmtpd_mheader_skip_cfws(ptr, 0)) != NULL)
395 			continue;
396 		return prev;
397 	}
398 }
399 
400 char *
401 osmtpd_mheader_skip_phrase(char *ptr, int optional)
402 {
403 	/* obs-phrase is a superset of phrae */
404 	return osmtpd_mheader_skip_obs_phrase(ptr, optional);
405 #if 0
406 	char *start = ptr, *prev;
407 
408 	if ((ptr = osmtpd_mheader_skip_word(ptr, 0)) == NULL)
409 		return optional ? start : NULL;
410 	while (1) {
411 		prev = ptr;
412 		if ((ptr = osmtpd_mheader_skip_word(ptr, 0)) == NULL)
413 			return prev;
414 	}
415 #endif
416 }
417 
418 char *
419 osmtpd_mheader_skip_obs_local_part(char *ptr, int optional)
420 {
421 	char *start = ptr, *prev;
422 
423 	if ((ptr = osmtpd_mheader_skip_word(ptr, 0)) == NULL)
424 		return optional ? start : NULL;
425 	prev = ptr;
426 	while (ptr[0] == '.') {
427 		ptr++;
428 		if ((ptr = osmtpd_mheader_skip_word(ptr, 0)) == NULL)
429 			return prev;
430 		prev = ptr;
431 	}
432 	return ptr;
433 }
434 
435 char *
436 osmtpd_mheader_skip_local_part(char *ptr, int optional)
437 {
438 	char *start = ptr;
439 
440 	if ((ptr = osmtpd_mheader_skip_dot_atom(ptr, 0)) != NULL)
441 		return ptr;
442 	ptr = start;
443 	if ((ptr = osmtpd_mheader_skip_quoted_string(ptr, 0)) != NULL)
444 		return ptr;
445 	return osmtpd_mheader_skip_obs_local_part(start, optional);
446 }
447 
448 char *
449 osmtpd_mheader_skip_obs_dtext(char *ptr, int optional)
450 {
451 	char *start = ptr;
452 
453 	if ((ptr = osmtpd_mheader_skip_obs_no_ws_ctl(ptr, 0)) != NULL)
454 		return ptr;
455 	return osmtpd_mheader_skip_quoted_pair(start, optional);
456 }
457 
458 char *
459 osmtpd_mheader_skip_dtext(char *ptr, int optional)
460 {
461 	if ((ptr[0] >= 33 && ptr[0] <= 90) || (ptr[0] >= 94 && ptr[0] <= 126))
462 		return ptr + 1;
463 	return osmtpd_mheader_skip_obs_dtext(ptr, optional);
464 
465 }
466 
467 char *
468 osmtpd_mheader_skip_domain_literal(char *ptr, int optional)
469 {
470 	char *start = ptr, *prev;
471 
472 	ptr = osmtpd_mheader_skip_cfws(ptr, 1);
473 	if (ptr++[0] != '[')
474 		return optional ? start : NULL;
475 	while (1) {
476 		ptr = osmtpd_mheader_skip_fws(ptr, 1);
477 		prev = ptr;
478 		if ((ptr = osmtpd_mheader_skip_dtext(ptr, 0)) == NULL) {
479 			ptr = prev;
480 			break;
481 		}
482 	}
483 	if (ptr[0] != ']')
484 		return optional ? start : NULL;
485 	ptr++;
486 	return osmtpd_mheader_skip_cfws(ptr, 1);
487 }
488 
489 char *
490 osmtpd_mheader_skip_obs_domain(char *ptr, int optional)
491 {
492 	char *start = ptr, *prev;
493 
494 	if ((ptr = osmtpd_mheader_skip_atom(ptr, 0)) == NULL)
495 		return optional ? start : NULL;
496 	prev = ptr;
497 	while (1) {
498 		if (ptr++[0] != '.')
499 			return prev;
500 		if ((ptr = osmtpd_mheader_skip_atom(ptr, 0)) == NULL)
501 			return prev;
502 		prev = ptr;
503 	}
504 }
505 
506 char *
507 osmtpd_mheader_skip_domain(char *ptr, int optional)
508 {
509 	char *start = ptr;
510 
511 	if ((ptr = osmtpd_mheader_skip_dot_atom(start, 0)) != NULL)
512 		return ptr;
513 	if ((ptr = osmtpd_mheader_skip_domain_literal(start, 0)) != NULL)
514 		return ptr;
515 	return osmtpd_mheader_skip_obs_domain(start, optional);
516 }
517 
518 char *
519 osmtpd_mheader_skip_display_name(char *ptr, int optional)
520 {
521 	return osmtpd_mheader_skip_phrase(ptr, optional);
522 }
523 
524 char *
525 osmtpd_mheader_skip_obs_domain_list(char *ptr, int optional)
526 {
527 	char *start = ptr, *prev = ptr;
528 
529 	while (1) {
530 		if (ptr[0] == ',') {
531 			ptr++;
532 			prev = ptr;
533 			continue;
534 		} else if ((ptr = osmtpd_mheader_skip_cfws(ptr, 0)) != NULL) {
535 			prev = ptr;
536 			continue;
537 		}
538 		break;
539 	}
540 	ptr = prev;
541 
542 	if (ptr++[0] != '@')
543 		return optional ? start : NULL;
544 	if ((ptr = osmtpd_mheader_skip_domain(ptr, 0)) == NULL)
545 		return optional ? start : NULL;
546 	while (1) {
547 		if (ptr[0] != ',')
548 			break;
549 		ptr++;
550 		ptr = osmtpd_mheader_skip_cfws(ptr, 1);
551 		if (ptr[0] != '@')
552 			continue;
553 		prev = ptr;
554 		if ((ptr = osmtpd_mheader_skip_domain(ptr + 1, 0)) == NULL) {
555 			ptr = prev;
556 			break;
557 		}
558 	}
559 	return ptr;
560 }
561 
562 char *
563 osmtpd_mheader_skip_obs_route(char *ptr, int optional)
564 {
565 	char *start = ptr;
566 
567 	if ((ptr = osmtpd_mheader_skip_obs_domain_list(ptr, 0)) == NULL)
568 		return optional ? start : NULL;
569 	if (ptr++[0] != ':')
570 		return optional ? start : NULL;
571 	return ptr;
572 }
573 
574 char *
575 osmtpd_mheader_skip_addr_spec(char *ptr, int optional)
576 {
577 	char *start = ptr;
578 
579 	if ((ptr = osmtpd_mheader_skip_local_part(ptr, 0)) == NULL)
580 		return optional ? start : NULL;
581 	if (ptr++[0] != '@')
582 		return optional ? start : NULL;
583 	if ((ptr = osmtpd_mheader_skip_domain(ptr, 0)) == NULL)
584 		return optional ? start : NULL;
585 	return ptr;
586 }
587 
588 char *
589 osmtpd_mheader_skip_obs_angle_addr(char *ptr, int optional)
590 {
591 	char *start = ptr;
592 
593 	ptr = osmtpd_mheader_skip_cfws(ptr, 1);
594 	if (ptr++[0] != '<')
595 		return optional ? start : NULL;
596 	if ((ptr = osmtpd_mheader_skip_obs_route(ptr, 0)) == NULL)
597 		return optional ? start : NULL;
598 	if ((ptr = osmtpd_mheader_skip_addr_spec(ptr, 0)) == NULL)
599 		return optional ? start : NULL;
600 	if (ptr++[0] != '>')
601 		return optional ? start : NULL;
602 	return osmtpd_mheader_skip_cfws(ptr, 1);
603 }
604 
605 char *
606 osmtpd_mheader_skip_angle_addr(char *ptr, int optional)
607 {
608 	char *start = ptr;
609 
610 	ptr = osmtpd_mheader_skip_cfws(ptr, 1);
611 	if (ptr++[0] != '<')
612 		return osmtpd_mheader_skip_obs_angle_addr(start, optional);
613 	if ((ptr = osmtpd_mheader_skip_addr_spec(ptr, 0)) == NULL)
614 		return osmtpd_mheader_skip_obs_angle_addr(start, optional);
615 	if (ptr++[0] != '>')
616 		return osmtpd_mheader_skip_obs_angle_addr(start, optional);
617 	return osmtpd_mheader_skip_cfws(ptr, 1);
618 }
619 
620 char *
621 osmtpd_mheader_skip_name_addr(char *ptr, int optional)
622 {
623 	char *start = ptr;
624 
625 	ptr = osmtpd_mheader_skip_display_name(ptr, 1);
626 	if ((ptr = osmtpd_mheader_skip_angle_addr(ptr, 0)) == NULL)
627 		return optional ? start : NULL;
628 	return ptr;
629 }
630 
631 char *
632 osmtpd_mheader_domain_uncomment(char *ptr)
633 {
634 	char *domain0, *domain, *tmp, *end;
635 
636 	if (osmtpd_mheader_skip_dot_atom(ptr, 0) != NULL) {
637 		ptr = osmtpd_mheader_skip_cfws(ptr, 1);
638 		return strndup(ptr,
639 		    osmtpd_mheader_skip_dot_atom_text(ptr, 0) - ptr);
640 	}
641 	if ((tmp = osmtpd_mheader_skip_domain_literal(ptr, 0)) != NULL) {
642 		ptr = osmtpd_mheader_skip_cfws(ptr, 1) + 1;
643 		domain0 = domain = strndup(ptr, (size_t)(tmp - ptr));
644 		if (domain0 == NULL)
645 			return NULL;
646 		end = domain0 + (tmp - ptr) + 1;
647 		domain++;
648 		while (1) {
649 			tmp = osmtpd_mheader_skip_fws(domain, 1);
650 			if (tmp != domain) {
651 				memmove(domain, tmp, end - tmp);
652 				end -= (tmp - domain);
653 			}
654 			tmp = osmtpd_mheader_skip_dtext(domain, 0);
655 			if (tmp == NULL)
656 				break;
657 			domain = tmp;
658 		}
659 		/* domain[0] ==  ']' */
660 		domain[0] = '\0';
661 		return domain0;
662 	}
663 	return strndup(ptr, osmtpd_mheader_skip_obs_domain(ptr, 1) - ptr);
664 }
665 
666 /* Return the domain component of the first mailbox */
667 char *
668 osmtpd_mheader_from_domain(char *ptr)
669 {
670 	char *tmp;
671 
672 	/* from */
673 	if (strncasecmp(ptr, "from:", 5) == 0) {
674 		ptr += 5;
675 	/* obs-from */
676 	} else if (strncasecmp(ptr, "from", 4) == 0) {
677 		ptr += 4;
678 		do {
679 			tmp = ptr;
680 		} while ((ptr = osmtpd_mheader_skip_wsp(ptr, 0)) != NULL);
681 		ptr = tmp;
682 		if (ptr++[0] != ':')
683 			return NULL;
684 	} else {
685 		errno = EINVAL;
686 		return NULL;
687 	}
688 
689 	/* Both from and obs-from use Mailbox-list CRLF */
690 	/* obs-mbox-list has just a prefix compared to mailbox-list */
691 	while (1) {
692 		tmp = ptr;
693 		ptr = osmtpd_mheader_skip_cfws(ptr, 1);
694 		if (ptr++[0] != ',') {
695 			ptr = tmp;
696 			break;
697 		}
698 	}
699 	/* We're only interested in the first mailbox */
700 	if (osmtpd_mheader_skip_name_addr(ptr, 0) != NULL) {
701 		ptr = osmtpd_mheader_skip_display_name(ptr, 1);
702 		ptr = osmtpd_mheader_skip_cfws(ptr, 1);
703 		/* < */
704 		ptr++;
705 		/* addr-spec */
706 		ptr = osmtpd_mheader_skip_local_part(ptr, 0);
707 		/* @ */
708 		ptr++;
709 		return osmtpd_mheader_domain_uncomment(ptr);
710 	}
711 	if (osmtpd_mheader_skip_addr_spec(ptr, 0) != NULL) {
712 		ptr = osmtpd_mheader_skip_local_part(ptr, 0);
713 		/* @ */
714 		ptr++;
715 		return osmtpd_mheader_domain_uncomment(ptr);
716 	}
717 	errno = EINVAL;
718 	return NULL;
719 }