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Date:: Sun Aug 30 19:24:18 2020 UTC
Message:: Use new osmtpd_mheader_skip_* API
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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 char *
26 osmtpd_mheader_skip_sp(char *ptr, int optional)
27 {
28 	if (ptr[0] == 0x20)
29 		return ptr + 1;
30 	return optional ? ptr : NULL;
31 }
32 
33 char *
34 osmtpd_mheader_skip_htab(char *ptr, int optional)
35 {
36 	if (ptr[0] == 0x9)
37 		return ptr + 1;
38 	return optional ? ptr : NULL;
39 }
40 
41 char *
42 osmtpd_mheader_skip_wsp(char *ptr, int optional)
43 {
44 	char *start = ptr;
45 
46 	if ((ptr = osmtpd_mheader_skip_sp(start, 0)) != NULL ||
47 	    (ptr = osmtpd_mheader_skip_htab(start, 0)) != NULL)
48 		return ptr;
49 	return optional ? ptr : NULL;
50 }
51 
52 char *
53 osmtpd_mheader_skip_crlf(char *ptr, int optional)
54 {
55 	if (ptr[0] == 13 && ptr[1] == 10)
56 		return ptr + 2;
57 	return optional ? ptr : NULL;
58 }
59 
60 char *
61 osmtpd_mheader_skip_vchar(char *ptr, int optional)
62 {
63 	if (ptr[0] >= 0x21 && ptr[0] <= 0x7e)
64 		return ptr + 1;
65 	return optional ? ptr : NULL;
66 }
67 
68 char *
69 osmtpd_mheader_skip_lf(char *ptr, int optional)
70 {
71 	if (ptr[0] == 0xa)
72 		return ptr + 1;
73 	return optional ? ptr : NULL;
74 }
75 
76 char *
77 osmtpd_mheader_skip_cr(char *ptr, int optional)
78 {
79 	if (ptr[0] == 0xd)
80 		return ptr + 1;
81 	return optional ? ptr : NULL;
82 }
83 
84 char *
85 osmtpd_mheader_skip_alpha(char *ptr, int optional)
86 {
87 	if ((ptr[0] >= 0x41 && ptr[0] <= 0x5a) ||
88 	    (ptr[0] >= 0x61 && ptr[0] <= 0x7a))
89 		return ptr + 1;
90 	return optional ? ptr : NULL;
91 }
92 
93 char *
94 osmtpd_mheader_skip_digit(char *ptr, int optional)
95 {
96 	if (ptr[0] >= 0x30 && ptr[0] <= 0x39)
97 		return ptr + 1;
98 	return optional ? ptr : NULL;
99 }
100 
101 char *
102 osmtpd_mheader_skip_dquote(char *ptr, int optional)
103 {
104 	if (ptr[0] == 0x22)
105 		return ptr + 1;
106 	return optional ? ptr : NULL;
107 }
108 
109 char *
110 osmtpd_mheader_skip_char(char *ptr, int optional)
111 {
112 	if (ptr[0] >= 0x1 && ptr[0] <= 0x7f)
113 		return ptr + 1;
114 	return optional ? ptr : NULL;
115 }
116 
117 char *
118 osmtpd_mheader_skip_ctl(char *ptr, int optional)
119 {
120 	if ((ptr[0] >= 0x0 && ptr[0] <= 0x1f) || ptr[0] == 0x7f)
121 		return ptr + 1;
122 	return optional ? ptr : NULL;
123 }
124 
125 char *
126 osmtpd_mheader_skip_obs_fws(char *ptr, int optional)
127 {
128 	char *start = ptr, *prev;
129 
130 	if ((ptr = osmtpd_mheader_skip_wsp(ptr, 0)) == NULL)
131 		return optional ? start : NULL;
132 	prev = ptr;
133 	while ((ptr = osmtpd_mheader_skip_wsp(ptr, 0)) != NULL)
134 		prev = ptr;
135 
136 	ptr = prev;
137 	while (1) {
138 		if ((ptr = osmtpd_mheader_skip_crlf(ptr, 0)) == NULL)
139 			return prev;
140 		if ((ptr = osmtpd_mheader_skip_wsp(ptr, 0)) == NULL)
141 			return prev;
142 		prev = ptr;
143 		while ((ptr = osmtpd_mheader_skip_wsp(ptr, 0)) != NULL)
144 			prev = ptr;
145 		ptr = prev;
146 	}
147 }
148 
149 char *
150 osmtpd_mheader_skip_fws(char *ptr, int optional)
151 {
152 	char *start = ptr, *prev = ptr;
153 
154 	while ((ptr = osmtpd_mheader_skip_wsp(ptr, 0)) != NULL)
155 		prev = ptr;
156 	if ((ptr = osmtpd_mheader_skip_crlf(prev, 1)) == prev)
157 		ptr = start;
158 	if ((ptr = osmtpd_mheader_skip_wsp(ptr, 0)) == NULL)
159 		return osmtpd_mheader_skip_obs_fws(start, optional);
160 	prev = ptr;
161 	while ((ptr = osmtpd_mheader_skip_wsp(ptr, 0)) != NULL)
162 		prev = ptr;
163 	return prev;
164 }
165 
166 char *
167 osmtpd_mheader_skip_obs_no_ws_ctl(char *ptr, int optional)
168 {
169 	if ((ptr[0] >= 1 && ptr[0] <= 8) || ptr[0] == 11 || ptr[0] == 12 ||
170 	    (ptr[0] >= 14 && ptr[0] <= 31) || ptr[0] == 127)
171 		return ptr + 1;
172 	return optional ? ptr : NULL;
173 }
174 
175 char *
176 osmtpd_mheader_skip_obs_ctext(char *ptr, int optional)
177 {
178 	return osmtpd_mheader_skip_obs_no_ws_ctl(ptr, optional);
179 }
180 
181 char *
182 osmtpd_mheader_skip_ctext(char *ptr, int optional)
183 {
184 	char *start = ptr;
185 
186 	if ((ptr[0] >= 33 && ptr[0] <= 39) || (ptr[0] >= 42 && ptr[0] <= 91) ||
187 	    (ptr[0] >= 93 && ptr[0] <= 126))
188 		return ptr + 1;
189 	if ((ptr = osmtpd_mheader_skip_obs_ctext(ptr, 0)) != NULL)
190 		return ptr;
191 	return optional ? start : NULL;
192 }
193 
194 char *
195 osmtpd_mheader_skip_obs_qp(char *ptr, int optional)
196 {
197 	char *start = ptr;
198 
199 	if (ptr[0] == '\\' && (
200 	    (ptr = osmtpd_mheader_skip_obs_no_ws_ctl(start + 1, 0)) != NULL ||
201 	    (ptr = osmtpd_mheader_skip_lf(start + 1, 0)) != NULL ||
202 	    (ptr = osmtpd_mheader_skip_cr(start + 1, 0)) != NULL))
203 		return ptr;
204 	return optional ? start : NULL;
205 }
206 
207 char *
208 osmtpd_mheader_skip_quoted_pair(char *ptr, int optional)
209 {
210 	char *start = ptr;
211 
212 	if (ptr[0] == '\\' && (
213 	    (ptr = osmtpd_mheader_skip_vchar(start + 1, 0)) != NULL ||
214 	    (ptr = osmtpd_mheader_skip_wsp(start + 1, 0)) != NULL))
215 		return ptr;
216 	return osmtpd_mheader_skip_obs_qp(start, optional);
217 }
218 
219 char *
220 osmtpd_mheader_skip_ccontent(char *ptr, int optional)
221 {
222 	char *start = ptr;
223 
224 	if ((ptr = osmtpd_mheader_skip_ctext(ptr, 0)) != NULL)
225 		return ptr;
226 	if ((ptr = osmtpd_mheader_skip_quoted_pair(start, 0)) != NULL)
227 		return ptr;
228 	if ((ptr = osmtpd_mheader_skip_comment(start, 0)) != NULL)
229 		return ptr;
230 	return optional ? start : NULL;
231 }
232 
233 char *
234 osmtpd_mheader_skip_comment(char *ptr, int optional)
235 {
236 	char *start = ptr;
237 
238 	if (ptr++[0] != '(')
239 		return optional ? start : NULL;
240 	while (1) {
241 		ptr = osmtpd_mheader_skip_fws(ptr, 1);
242 		if (ptr[0] == ')')
243 			return ptr + 1;
244 		if ((ptr = osmtpd_mheader_skip_ccontent(ptr, 0)) == NULL)
245 			return optional ? start : NULL;
246 	}
247 }
248 
249 char *
250 osmtpd_mheader_skip_cfws(char *ptr, int optional)
251 {
252 	char *start = ptr, *prev;
253 
254 	while (1) {
255 		ptr = osmtpd_mheader_skip_fws(ptr, 1);
256 		prev = ptr;
257 		if ((ptr = osmtpd_mheader_skip_comment(ptr, 0)) == NULL) {
258 			ptr = prev;
259 			break;
260 		}
261 	}
262 	return ptr == start && !optional ? NULL : ptr;
263 }
264 
265 char *
266 osmtpd_mheader_skip_atext(char *ptr, int optional)
267 {
268 	char *start = ptr;
269 
270 	if ((ptr = osmtpd_mheader_skip_alpha(start, 0)) != NULL ||
271 	    (ptr = osmtpd_mheader_skip_digit(start, 0)) != NULL)
272 		return ptr;
273 	ptr = start;
274 	if (ptr[0] == '!' || ptr[0] == '#' || ptr[0] == '$' || ptr[0] == '%' ||
275 	    ptr[0] == '&' || ptr[0] == '\'' || ptr[0] == '*' || ptr[0] == '+' ||
276 	    ptr[0] == '-' || ptr[0] == '/' || ptr[0] == '=' || ptr[0] == '?' ||
277 	    ptr[0] == '^' || ptr[0] == '_' || ptr[0] == '`' || ptr[0] == '{' ||
278 	    ptr[0] == '|' || ptr[0] == '}' || ptr[0] == '~')
279 		return ptr + 1;
280 	return optional ? start : NULL;
281 }
282 
283 char *
284 osmtpd_mheader_skip_atom(char *ptr, int optional)
285 {
286 	char *start = ptr, *prev;
287 
288 	ptr = osmtpd_mheader_skip_cfws(ptr, 1);
289 	if ((ptr = osmtpd_mheader_skip_atext(ptr, 0)) == NULL)
290 		return optional ? start : NULL;
291 	do {
292 		prev = ptr;
293 		ptr = osmtpd_mheader_skip_atext(ptr, 1);
294 	} while (prev != ptr);
295 	return osmtpd_mheader_skip_cfws(ptr, 1);
296 }
297 
298 char *
299 osmtpd_mheader_skip_dot_atom_text(char *ptr, int optional)
300 {
301 	char *start = ptr, *prev;
302 
303 	if ((ptr = osmtpd_mheader_skip_atext(ptr, 0)) == NULL)
304 		return optional ? start : NULL;
305 	do {
306 		prev = ptr;
307 		ptr = osmtpd_mheader_skip_atext(ptr, 1);
308 	} while (ptr != prev);
309 
310 	while (ptr[0] == '.') {
311 		ptr++;
312 		if ((ptr = osmtpd_mheader_skip_atext(ptr, 0)) == NULL)
313 			return prev;
314 		do {
315 			prev = ptr;
316 			ptr = osmtpd_mheader_skip_atext(ptr, 1);
317 		} while (ptr != prev);
318 	}
319 	return ptr;
320 }
321 
322 char *
323 osmtpd_mheader_skip_dot_atom(char *ptr, int optional)
324 {
325 	char *start = ptr;
326 
327 	ptr = osmtpd_mheader_skip_cfws(ptr, 1);
328 	if ((ptr = osmtpd_mheader_skip_dot_atom_text(ptr, 0)) == NULL)
329 		return optional ? start : NULL;
330 	return osmtpd_mheader_skip_cfws(ptr, 1);
331 }
332 
333 
334 char *
335 osmtpd_mheader_skip_obs_qtext(char *ptr, int optional)
336 {
337 	return osmtpd_mheader_skip_obs_no_ws_ctl(ptr, optional);
338 }
339 
340 char *
341 osmtpd_mheader_skip_qtext(char *ptr, int optional)
342 {
343 	char *start = ptr;
344 
345 	if (ptr[0] == 33 || (ptr[0] >= 35 && ptr[0] <= 91) ||
346 	    (ptr[0] >= 93 && ptr[0] <= 126))
347 		return ptr + 1;
348 	if ((ptr = osmtpd_mheader_skip_obs_qtext(ptr, 0)) != NULL)
349 		return ptr;
350 	return optional ? start : NULL;
351 }
352 
353 char *
354 osmtpd_mheader_skip_qcontent(char *ptr, int optional)
355 {
356 	char *start = ptr;
357 
358 	if ((ptr = osmtpd_mheader_skip_qtext(ptr, 0)) != NULL)
359 		return ptr;
360 	return osmtpd_mheader_skip_quoted_pair(start, optional);
361 }
362 
363 char *
364 osmtpd_mheader_skip_quoted_string(char *ptr, int optional)
365 {
366 	char *start = ptr, *prev;
367 
368 	ptr = osmtpd_mheader_skip_cfws(ptr, 1);
369 	if ((ptr = osmtpd_mheader_skip_dquote(ptr, 0)) == NULL)
370 		return optional ? start : NULL;
371 	prev = ptr;
372 	while (1) {
373 		ptr = osmtpd_mheader_skip_fws(ptr, 1);
374 		if ((ptr = osmtpd_mheader_skip_qcontent(ptr, 0)) == NULL)
375 			break;
376 		prev = ptr;
377 	}
378 	if ((ptr = osmtpd_mheader_skip_dquote(prev, 0)) == NULL)
379 		return optional ? start : NULL;
380 	return osmtpd_mheader_skip_cfws(ptr, 1);
381 }
382 
383 char *
384 osmtpd_mheader_skip_word(char *ptr, int optional)
385 {
386 	char *start = ptr;
387 
388 	if ((ptr = osmtpd_mheader_skip_atom(ptr, 0)) != NULL)
389 		return ptr;
390 	return osmtpd_mheader_skip_quoted_string(start, optional);
391 }
392 
393 char *
394 osmtpd_mheader_skip_obs_phrase(char *ptr, int optional)
395 {
396 	char *start = ptr, *prev;
397 
398 	if ((ptr = osmtpd_mheader_skip_word(ptr, 0)) == NULL)
399 		return optional ? start : NULL;
400 	while (1) {
401 		prev = ptr;
402 		if ((ptr = osmtpd_mheader_skip_word(ptr, 0)) != NULL)
403 			continue;
404 		ptr = prev;
405 		if (ptr[0] == '.')
406 			continue;
407 		if ((ptr = osmtpd_mheader_skip_cfws(ptr, 0)) != NULL)
408 			continue;
409 		return prev;
410 	}
411 }
412 
413 char *
414 osmtpd_mheader_skip_phrase(char *ptr, int optional)
415 {
416 	/* obs-phrase is a superset of phrae */
417 	return osmtpd_mheader_skip_obs_phrase(ptr, optional);
418 #if 0
419 	char *start = ptr, *prev;
420 
421 	if ((ptr = osmtpd_mheader_skip_word(ptr, 0)) == NULL)
422 		return optional ? start : NULL;
423 	while (1) {
424 		prev = ptr;
425 		if ((ptr = osmtpd_mheader_skip_word(ptr, 0)) == NULL)
426 			return prev;
427 	}
428 #endif
429 }
430 
431 char *
432 osmtpd_mheader_skip_obs_local_part(char *ptr, int optional)
433 {
434 	char *start = ptr, *prev;
435 
436 	if ((ptr = osmtpd_mheader_skip_word(ptr, 0)) == NULL)
437 		return optional ? start : NULL;
438 	prev = ptr;
439 	while (ptr[0] == '.') {
440 		ptr++;
441 		if ((ptr = osmtpd_mheader_skip_word(ptr, 0)) == NULL)
442 			return prev;
443 		prev = ptr;
444 	}
445 	return ptr;
446 }
447 
448 char *
449 osmtpd_mheader_skip_local_part(char *ptr, int optional)
450 {
451 	char *start = ptr;
452 
453 	if ((ptr = osmtpd_mheader_skip_dot_atom(ptr, 0)) != NULL)
454 		return ptr;
455 	ptr = start;
456 	if ((ptr = osmtpd_mheader_skip_quoted_string(ptr, 0)) != NULL)
457 		return ptr;
458 	return osmtpd_mheader_skip_obs_local_part(start, optional);
459 }
460 
461 char *
462 osmtpd_mheader_skip_obs_dtext(char *ptr, int optional)
463 {
464 	char *start = ptr;
465 
466 	if ((ptr = osmtpd_mheader_skip_obs_no_ws_ctl(ptr, 0)) != NULL)
467 		return ptr;
468 	return osmtpd_mheader_skip_quoted_pair(start, optional);
469 }
470 
471 char *
472 osmtpd_mheader_skip_dtext(char *ptr, int optional)
473 {
474 	if ((ptr[0] >= 33 && ptr[0] <= 90) || (ptr[0] >= 94 && ptr[0] <= 126))
475 		return ptr + 1;
476 	return osmtpd_mheader_skip_obs_dtext(ptr, optional);
477 
478 }
479 
480 char *
481 osmtpd_mheader_skip_domain_literal(char *ptr, int optional)
482 {
483 	char *start = ptr, *prev;
484 
485 	ptr = osmtpd_mheader_skip_cfws(ptr, 1);
486 	if (ptr++[0] != '[')
487 		return optional ? start : NULL;
488 	while (1) {
489 		ptr = osmtpd_mheader_skip_fws(ptr, 1);
490 		prev = ptr;
491 		if ((ptr = osmtpd_mheader_skip_dtext(ptr, 0)) == NULL) {
492 			ptr = prev;
493 			break;
494 		}
495 	}
496 	if (ptr[0] != ']')
497 		return optional ? start : NULL;
498 	return osmtpd_mheader_skip_cfws(ptr, 1);
499 }
500 
501 char *
502 osmtpd_mheader_skip_obs_domain(char *ptr, int optional)
503 {
504 	char *start = ptr, *prev;
505 
506 	if ((ptr = osmtpd_mheader_skip_atom(ptr, 0)) == NULL)
507 		return optional ? start : NULL;
508 	prev = ptr;
509 	while (1) {
510 		if (ptr++[0] != '.')
511 			return prev;
512 		if ((ptr = osmtpd_mheader_skip_atom(ptr, 0)) == NULL)
513 			return prev;
514 		prev = ptr;
515 	}
516 }
517 
518 char *
519 osmtpd_mheader_skip_domain(char *ptr, int optional)
520 {
521 	char *start = ptr;
522 
523 	if ((ptr = osmtpd_mheader_skip_dot_atom(start, 0)) != NULL)
524 		return ptr;
525 	if ((ptr = osmtpd_mheader_skip_domain_literal(start, 0)) != NULL)
526 		return ptr;
527 	return osmtpd_mheader_skip_obs_domain(start, optional);
528 }
529 
530 char *
531 osmtpd_mheader_skip_display_name(char *ptr, int optional)
532 {
533 	return osmtpd_mheader_skip_phrase(ptr, optional);
534 }
535 
536 char *
537 osmtpd_mheader_skip_obs_domain_list(char *ptr, int optional)
538 {
539 	char *start = ptr, *prev;
540 
541 	while (1) {
542 		if (ptr[0] == ',') {
543 			ptr++;
544 			prev = ptr;
545 			continue;
546 		} else if ((ptr = osmtpd_mheader_skip_cfws(ptr, 0)) != NULL) {
547 			prev = ptr;
548 			continue;
549 		}
550 		break;
551 	}
552 	ptr = prev;
553 
554 	if (ptr++[0] != '@')
555 		return optional ? start : NULL;
556 	if ((ptr = osmtpd_mheader_skip_domain(ptr, 0)) == NULL)
557 		return optional ? start : NULL;
558 	while (1) {
559 		if (ptr[0] != ',')
560 			break;
561 		ptr++;
562 		ptr = osmtpd_mheader_skip_cfws(ptr, 1);
563 		if (ptr[0] != '@')
564 			continue;
565 		prev = ptr;
566 		if ((ptr = osmtpd_mheader_skip_domain(ptr + 1, 0)) == NULL) {
567 			ptr = prev;
568 			break;
569 		}
570 	}
571 	return ptr;
572 }
573 
574 char *
575 osmtpd_mheader_skip_obs_route(char *ptr, int optional)
576 {
577 	char *start = ptr;
578 
579 	if ((ptr = osmtpd_mheader_skip_obs_domain_list(ptr, 0)) == NULL)
580 		return optional ? start : NULL;
581 	if (ptr++[0] != ':')
582 		return optional ? start : NULL;
583 	return ptr;
584 }
585 
586 char *
587 osmtpd_mheader_skip_addr_spec(char *ptr, int optional)
588 {
589 	char *start = ptr;
590 
591 	if ((ptr = osmtpd_mheader_skip_local_part(ptr, 0)) == NULL)
592 		return optional ? start : NULL;
593 	if (ptr++[0] != '@')
594 		return optional ? start : NULL;
595 	if ((ptr = osmtpd_mheader_skip_domain(ptr, 0)) == NULL)
596 		return optional ? start : NULL;
597 	return ptr;
598 }
599 
600 char *
601 osmtpd_mheader_skip_obs_angle_addr(char *ptr, int optional)
602 {
603 	char *start = ptr;
604 
605 	ptr = osmtpd_mheader_skip_cfws(ptr, 1);
606 	if (ptr++[0] != '<')
607 		return optional ? start : NULL;
608 	if ((ptr = osmtpd_mheader_skip_obs_route(ptr, 0)) == NULL)
609 		return optional ? start : NULL;
610 	if ((ptr = osmtpd_mheader_skip_addr_spec(ptr, 0)) == NULL)
611 		return optional ? start : NULL;
612 	if (ptr++[0] != '>')
613 		return optional ? start : NULL;
614 	return osmtpd_mheader_skip_cfws(ptr, 1);
615 }
616 
617 char *
618 osmtpd_mheader_skip_angle_addr(char *ptr, int optional)
619 {
620 	char *start = ptr;
621 
622 	ptr = osmtpd_mheader_skip_cfws(ptr, 1);
623 	if (ptr++[0] != '<')
624 		return osmtpd_mheader_skip_obs_angle_addr(start, optional);
625 	if ((ptr = osmtpd_mheader_skip_addr_spec(ptr, 0)) == NULL)
626 		return osmtpd_mheader_skip_obs_angle_addr(start, optional);
627 	if (ptr++[0] != '>')
628 		return osmtpd_mheader_skip_obs_angle_addr(start, optional);
629 	return osmtpd_mheader_skip_cfws(ptr, 1);
630 }
631 
632 char *
633 osmtpd_mheader_skip_name_addr(char *ptr, int optional)
634 {
635 	char *start = ptr;
636 
637 	ptr = osmtpd_mheader_skip_display_name(ptr, 1);
638 	if ((ptr = osmtpd_mheader_skip_angle_addr(ptr, 0)) == NULL)
639 		return optional ? start : NULL;
640 	return ptr;
641 }
642 
643 /* RFC 2045 */
644 char *
645 osmtpd_mheader_skip_tspecials(char *ptr, int optional)
646 {
647 	if (ptr[0] == '(' || ptr[0] == ')' || ptr[0] == '<' || ptr[0] == '>' ||
648 	    ptr[0] == '@' || ptr[0] == ',' || ptr[0] == ';' || ptr[0] == ':' ||
649 	    ptr[0] == '\\' || ptr[0] == '\'' || ptr[0] == '/' ||
650 	    ptr[0] == '[' || ptr[0] == ']' || ptr[0] == '?' || ptr[0] == '=')
651 		return ptr + 1;
652 	return optional ? ptr : NULL;
653 
654 }
655 
656 char *
657 osmtpd_mheader_skip_token(char *ptr, int optional)
658 {
659 	if (osmtpd_mheader_skip_char(ptr, 0) == NULL)
660 		return optional ? ptr : NULL;
661 	/* Can't find the official definition for SPACE, so use WSP */
662 	if (osmtpd_mheader_skip_wsp(ptr, 0) != NULL)
663 		return optional ? ptr : NULL;
664 	if (osmtpd_mheader_skip_ctl(ptr, 0) != NULL)
665 		return optional ? ptr : NULL;
666 	if (osmtpd_mheader_skip_tspecials(ptr, 0) != NULL)
667 		return optional ? ptr : NULL;
668 	ptr++;
669 	while (1) {
670 		if (osmtpd_mheader_skip_char(ptr, 0) == NULL)
671 			return ptr;
672 		if (osmtpd_mheader_skip_wsp(ptr, 0) != NULL)
673 			return ptr;
674 		if (osmtpd_mheader_skip_ctl(ptr, 0) != NULL)
675 			return ptr;
676 		if (osmtpd_mheader_skip_tspecials(ptr, 0) != NULL)
677 			return ptr;
678 		ptr++;
679 	}
680 }
681 
682 char *
683 osmtpd_mheader_skip_value(char *ptr, int optional)
684 {
685 	char *start = ptr;
686 
687 	if ((ptr = osmtpd_mheader_skip_token(ptr, 0)) == NULL)
688 		return osmtpd_mheader_skip_quoted_string(start, optional);
689 	return ptr;
690 }
691 
692 /* Return the domain component of the first mailbox */
693 char *
694 osmtpd_mheader_from_domain(char *ptr)
695 {
696 	char *tmp;
697 
698 	/* from */
699 	if (strncasecmp(ptr, "from:", 5) == 0) {
700 		ptr += 5;
701 	/* obs-from */
702 	} else if (strncasecmp(ptr, "from", 4) == 0) {
703 		ptr += 4;
704 		do {
705 			tmp = ptr;
706 		} while ((ptr = osmtpd_mheader_skip_wsp(ptr, 0)) != NULL);
707 		ptr = tmp;
708 		if (ptr++[0] != ':')
709 			return NULL;
710 	} else {
711 		errno = EINVAL;
712 		return NULL;
713 	}
714 
715 	/* Both from and obs-from use Mailbox-list CRLF */
716 	/* obs-mbox-list has just a prefix compared to mailbox-list */
717 	while (1) {
718 		tmp = ptr;
719 		ptr = osmtpd_mheader_skip_cfws(ptr, 1);
720 		if (ptr++[0] != ',') {
721 			ptr = tmp;
722 			break;
723 		}
724 	}
725 	/* We're only interested in the first mailbox */
726 	if (osmtpd_mheader_skip_name_addr(ptr, 0) != NULL) {
727 		ptr = osmtpd_mheader_skip_display_name(ptr, 1);
728 		ptr = osmtpd_mheader_skip_cfws(ptr, 1);
729 		/* < */
730 		ptr++;
731 		/* addr-spec */
732 		ptr = osmtpd_mheader_skip_local_part(ptr, 0);
733 		/* @ */
734 		ptr++;
735 		tmp = osmtpd_mheader_skip_domain(ptr, 0);
736 		return strndup(ptr, tmp - ptr);
737 	}
738 	if (osmtpd_mheader_skip_addr_spec(ptr, 0) != NULL) {
739 		ptr = osmtpd_mheader_skip_local_part(ptr, 0);
740 		/* @ */
741 		ptr++;
742 		tmp = osmtpd_mheader_skip_domain(ptr, 0);
743 		return strndup(ptr, tmp - ptr);
744 	}
745 	errno = EINVAL;
746 	return NULL;
747 }