Commit | Line | Data |
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617d3932 JH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | /* Experimental ARC support for Exim | |
5 | Copyright (c) Jeremy Harris 2018 | |
6 | License: GPL | |
7 | */ | |
8 | ||
9 | #include "exim.h" | |
10 | #ifdef EXPERIMENTAL_ARC | |
11 | # if !defined SUPPORT_SPF | |
12 | # error SPF must also be enabled for ARC | |
13 | # elif defined DISABLE_DKIM | |
14 | # error DKIM must also be enabled for ARC | |
15 | # else | |
16 | ||
17 | # include "functions.h" | |
18 | # include "pdkim/pdkim.h" | |
19 | # include "pdkim/signing.h" | |
20 | ||
21 | extern pdkim_ctx * dkim_verify_ctx; | |
22 | extern pdkim_ctx dkim_sign_ctx; | |
23 | ||
24 | /******************************************************************************/ | |
25 | ||
26 | typedef struct hdr_rlist { | |
27 | struct hdr_rlist * prev; | |
28 | BOOL used; | |
29 | header_line * h; | |
30 | } hdr_rlist; | |
31 | ||
32 | typedef struct arc_line { | |
33 | header_line * complete; /* including the header name; nul-term */ | |
34 | uschar * relaxed; | |
35 | ||
36 | /* identified tag contents */ | |
37 | /*XXX t= for AS? */ | |
38 | blob i; | |
39 | blob cv; | |
40 | blob a; | |
41 | blob b; | |
42 | blob bh; | |
43 | blob d; | |
44 | blob h; | |
45 | blob s; | |
46 | blob c; | |
47 | blob l; | |
48 | ||
49 | /* tag content sub-portions */ | |
50 | blob a_algo; | |
51 | blob a_hash; | |
52 | ||
53 | blob c_head; | |
54 | blob c_body; | |
55 | ||
56 | /* modified copy of b= field in line */ | |
57 | blob rawsig_no_b_val; | |
58 | } arc_line; | |
59 | ||
60 | typedef struct arc_set { | |
61 | struct arc_set * next; | |
62 | struct arc_set * prev; | |
63 | ||
64 | unsigned instance; | |
65 | arc_line * hdr_aar; | |
66 | arc_line * hdr_ams; | |
67 | arc_line * hdr_as; | |
68 | ||
93c931f8 | 69 | const uschar * ams_verify_done; |
617d3932 JH |
70 | BOOL ams_verify_passed; |
71 | } arc_set; | |
72 | ||
73 | typedef struct arc_ctx { | |
74 | arc_set * arcset_chain; | |
75 | arc_set * arcset_chain_last; | |
76 | } arc_ctx; | |
77 | ||
78 | #define ARC_HDR_AAR US"ARC-Authentication-Results:" | |
79 | #define ARC_HDRLEN_AAR 27 | |
80 | #define ARC_HDR_AMS US"ARC-Message-Signature:" | |
81 | #define ARC_HDRLEN_AMS 22 | |
82 | #define ARC_HDR_AS US"ARC-Seal:" | |
83 | #define ARC_HDRLEN_AS 9 | |
84 | #define HDR_AR US"Authentication-Results:" | |
85 | #define HDRLEN_AR 23 | |
86 | ||
87 | static hdr_rlist * headers_rlist; | |
88 | static arc_ctx arc_sign_ctx = { NULL }; | |
89 | ||
90 | ||
91 | /******************************************************************************/ | |
92 | ||
93 | ||
94 | /* Get the instance number from the header. | |
95 | Return 0 on error */ | |
96 | static unsigned | |
97 | arc_instance_from_hdr(const arc_line * al) | |
98 | { | |
978e78de | 99 | const uschar * s = al->i.data; |
617d3932 | 100 | if (!s || !al->i.len) return 0; |
978e78de | 101 | return (unsigned) atoi(CCS s); |
617d3932 JH |
102 | } |
103 | ||
104 | ||
105 | static uschar * | |
106 | skip_fws(uschar * s) | |
107 | { | |
108 | uschar c = *s; | |
109 | while (c && (c == ' ' || c == '\t' || c == '\n' || c == '\r')) c = *++s; | |
110 | return s; | |
111 | } | |
112 | ||
113 | ||
114 | /* Locate instance struct on chain, inserting a new one if | |
115 | needed. The chain is in increasing-instance-number order | |
116 | by the "next" link, and we have a "prev" link also. | |
117 | */ | |
118 | ||
119 | static arc_set * | |
120 | arc_find_set(arc_ctx * ctx, unsigned i) | |
121 | { | |
122 | arc_set ** pas, * as, * next, * prev; | |
123 | ||
124 | for (pas = &ctx->arcset_chain, prev = NULL, next = ctx->arcset_chain; | |
125 | as = *pas; pas = &as->next) | |
126 | { | |
127 | if (as->instance > i) break; | |
128 | if (as->instance == i) | |
129 | { | |
130 | DEBUG(D_acl) debug_printf("ARC: existing instance %u\n", i); | |
131 | return as; | |
132 | } | |
133 | next = as->next; | |
134 | prev = as; | |
135 | } | |
136 | ||
137 | DEBUG(D_acl) debug_printf("ARC: new instance %u\n", i); | |
138 | *pas = as = store_get(sizeof(arc_set)); | |
139 | memset(as, 0, sizeof(arc_set)); | |
140 | as->next = next; | |
141 | as->prev = prev; | |
142 | as->instance = i; | |
143 | if (next) | |
144 | next->prev = as; | |
145 | else | |
146 | ctx->arcset_chain_last = as; | |
147 | return as; | |
148 | } | |
149 | ||
150 | ||
151 | ||
152 | /* Insert a tag content into the line structure. | |
153 | Note this is a reference to existing data, not a copy. | |
154 | Check for already-seen tag. | |
155 | The string-pointer is on the '=' for entry. Update it past the | |
156 | content (to the ;) on return; | |
157 | */ | |
158 | ||
159 | static uschar * | |
160 | arc_insert_tagvalue(arc_line * al, unsigned loff, uschar ** ss) | |
161 | { | |
162 | uschar * s = *ss; | |
163 | uschar c = *++s; | |
164 | blob * b = (blob *)(US al + loff); | |
165 | size_t len = 0; | |
166 | ||
167 | /* [FWS] tag-value [FWS] */ | |
168 | ||
169 | if (b->data) return US"fail"; | |
170 | s = skip_fws(s); /* FWS */ | |
171 | ||
172 | b->data = s; | |
173 | while ((c = *s) && c != ';') { len++; s++; } | |
174 | *ss = s; | |
175 | while (len && ((c = s[-1]) == ' ' || c == '\t' || c == '\n' || c == '\r')) | |
176 | { s--; len--; } /* FWS */ | |
177 | b->len = len; | |
178 | return NULL; | |
179 | } | |
180 | ||
181 | ||
182 | /* Inspect a header line, noting known tag fields. | |
183 | Check for duplicates. */ | |
184 | ||
185 | static uschar * | |
186 | arc_parse_line(arc_line * al, header_line * h, unsigned off, BOOL instance_only) | |
187 | { | |
188 | uschar * s = h->text + off; | |
978e78de | 189 | uschar * r = NULL; /* compiler-quietening */ |
617d3932 JH |
190 | uschar c; |
191 | ||
192 | al->complete = h; | |
193 | ||
194 | if (!instance_only) | |
195 | { | |
196 | al->rawsig_no_b_val.data = store_get(h->slen + 1); | |
197 | memcpy(al->rawsig_no_b_val.data, h->text, off); /* copy the header name blind */ | |
198 | r = al->rawsig_no_b_val.data + off; | |
199 | al->rawsig_no_b_val.len = off; | |
200 | } | |
201 | ||
202 | /* tag-list = tag-spec *( ";" tag-spec ) [ ";" ] */ | |
203 | ||
204 | while ((c = *s)) | |
205 | { | |
206 | char tagchar; | |
207 | uschar * t; | |
208 | unsigned i = 0; | |
209 | uschar * fieldstart = s; | |
210 | uschar * bstart = NULL, * bend; | |
211 | ||
212 | /* tag-spec = [FWS] tag-name [FWS] "=" [FWS] tag-value [FWS] */ | |
213 | ||
214 | s = skip_fws(s); /* FWS */ | |
215 | if (!*s) break; | |
216 | /* debug_printf("%s: consider '%s'\n", __FUNCTION__, s); */ | |
217 | tagchar = *s++; | |
218 | s = skip_fws(s); /* FWS */ | |
219 | if (!*s) break; | |
220 | ||
221 | if (!instance_only || tagchar == 'i') switch (tagchar) | |
222 | { | |
223 | case 'a': /* a= AMS algorithm */ | |
224 | { | |
225 | if (*s != '=') return US"no 'a' value"; | |
226 | if (arc_insert_tagvalue(al, offsetof(arc_line, a), &s)) return US"a tag dup"; | |
227 | ||
228 | /* substructure: algo-hash (eg. rsa-sha256) */ | |
229 | ||
230 | t = al->a_algo.data = al->a.data; | |
231 | while (*t != '-') | |
232 | if (!*t++ || ++i > al->a.len) return US"no '-' in 'a' value"; | |
233 | al->a_algo.len = i; | |
234 | if (*t++ != '-') return US"no '-' in 'a' value"; | |
235 | al->a_hash.data = t; | |
236 | al->a_hash.len = al->a.len - i - 1; | |
237 | } | |
238 | break; | |
239 | case 'b': | |
240 | { | |
241 | gstring * g = NULL; | |
242 | ||
243 | switch (*s) | |
244 | { | |
245 | case '=': /* b= AMS signature */ | |
246 | if (al->b.data) return US"already b data"; | |
247 | bstart = s+1; | |
248 | ||
249 | /* The signature can have FWS inserted in the content; | |
250 | make a stripped copy */ | |
251 | ||
252 | while ((c = *++s) && c != ';') | |
253 | if (c != ' ' && c != '\t' && c != '\n' && c != '\r') | |
254 | g = string_catn(g, s, 1); | |
255 | al->b.data = string_from_gstring(g); | |
256 | al->b.len = g->ptr; | |
257 | gstring_reset_unused(g); | |
258 | bend = s; | |
259 | break; | |
260 | case 'h': /* bh= AMS body hash */ | |
261 | s = skip_fws(++s); /* FWS */ | |
262 | if (*s != '=') return US"no bh value"; | |
263 | if (al->bh.data) return US"already bh data"; | |
264 | ||
265 | /* The bodyhash can have FWS inserted in the content; | |
266 | make a stripped copy */ | |
267 | ||
268 | while ((c = *++s) && c != ';') | |
269 | if (c != ' ' && c != '\t' && c != '\n' && c != '\r') | |
270 | g = string_catn(g, s, 1); | |
271 | al->bh.data = string_from_gstring(g); | |
272 | al->bh.len = g->ptr; | |
273 | gstring_reset_unused(g); | |
274 | break; | |
275 | default: | |
276 | return US"b? tag"; | |
277 | } | |
278 | } | |
279 | break; | |
280 | case 'c': | |
281 | switch (*s) | |
282 | { | |
283 | case '=': /* c= AMS canonicalisation */ | |
284 | if (arc_insert_tagvalue(al, offsetof(arc_line, c), &s)) return US"c tag dup"; | |
285 | ||
286 | /* substructure: head/body (eg. relaxed/simple)) */ | |
287 | ||
288 | t = al->c_head.data = al->c.data; | |
289 | while (isalpha(*t)) | |
290 | if (!*t++ || ++i > al->a.len) break; | |
291 | al->c_head.len = i; | |
292 | if (*t++ == '/') /* /body is optional */ | |
293 | { | |
294 | al->c_body.data = t; | |
295 | al->c_body.len = al->c.len - i - 1; | |
296 | } | |
297 | else | |
298 | { | |
299 | al->c_body.data = US"simple"; | |
300 | al->c_body.len = 6; | |
301 | } | |
302 | break; | |
303 | case 'v': /* cv= AS validity */ | |
304 | if (*++s != '=') return US"cv tag val"; | |
305 | if (arc_insert_tagvalue(al, offsetof(arc_line, cv), &s)) return US"cv tag dup"; | |
306 | break; | |
307 | default: | |
308 | return US"c? tag"; | |
309 | } | |
310 | break; | |
311 | case 'd': /* d= AMS domain */ | |
312 | if (*s != '=') return US"d tag val"; | |
313 | if (arc_insert_tagvalue(al, offsetof(arc_line, d), &s)) return US"d tag dup"; | |
314 | break; | |
315 | case 'h': /* h= AMS headers */ | |
316 | if (*s != '=') return US"h tag val"; | |
317 | if (arc_insert_tagvalue(al, offsetof(arc_line, h), &s)) return US"h tag dup"; | |
318 | break; | |
319 | case 'i': /* i= ARC set instance */ | |
320 | if (*s != '=') return US"i tag val"; | |
321 | if (arc_insert_tagvalue(al, offsetof(arc_line, i), &s)) return US"i tag dup"; | |
322 | if (instance_only) goto done; | |
323 | break; | |
324 | case 'l': /* l= bodylength */ | |
325 | if (*s != '=') return US"l tag val"; | |
326 | if (arc_insert_tagvalue(al, offsetof(arc_line, l), &s)) return US"l tag dup"; | |
327 | break; | |
328 | case 's': /* s= AMS selector */ | |
329 | if (*s != '=') return US"s tag val"; | |
330 | if (arc_insert_tagvalue(al, offsetof(arc_line, s), &s)) return US"s tag dup"; | |
331 | break; | |
332 | } | |
333 | ||
334 | while ((c = *s) && c != ';') s++; | |
335 | if (c) s++; /* ; after tag-spec */ | |
336 | ||
337 | /* for all but the b= tag, copy the field including FWS. For the b=, | |
338 | drop the tag content. */ | |
339 | ||
340 | if (!instance_only) | |
341 | if (bstart) | |
342 | { | |
343 | size_t n = bstart - fieldstart; | |
344 | memcpy(r, fieldstart, n); /* FWS "b=" */ | |
345 | r += n; | |
346 | al->rawsig_no_b_val.len += n; | |
347 | n = s - bend; | |
348 | memcpy(r, bend, n); /* FWS ";" */ | |
349 | r += n; | |
350 | al->rawsig_no_b_val.len += n; | |
351 | } | |
352 | else | |
353 | { | |
354 | size_t n = s - fieldstart; | |
355 | memcpy(r, fieldstart, n); | |
356 | r += n; | |
357 | al->rawsig_no_b_val.len += n; | |
358 | } | |
359 | } | |
360 | ||
361 | if (!instance_only) | |
362 | *r = '\0'; | |
363 | ||
364 | done: | |
365 | /* debug_printf("%s: finshed\n", __FUNCTION__); */ | |
366 | return NULL; | |
367 | } | |
368 | ||
369 | ||
370 | /* Insert one header line in the correct set of the chain, | |
371 | adding instances as needed and checking for duplicate lines. | |
372 | */ | |
373 | ||
374 | static uschar * | |
375 | arc_insert_hdr(arc_ctx * ctx, header_line * h, unsigned off, unsigned hoff, | |
376 | BOOL instance_only) | |
377 | { | |
378 | int i; | |
379 | arc_set * as; | |
380 | arc_line * al = store_get(sizeof(arc_line)), ** alp; | |
381 | uschar * e; | |
382 | ||
383 | memset(al, 0, sizeof(arc_line)); | |
384 | ||
385 | if ((e = arc_parse_line(al, h, off, instance_only))) | |
386 | { | |
387 | DEBUG(D_acl) if (e) debug_printf("ARC: %s\n", e); | |
388 | return US"line parse"; | |
389 | } | |
390 | if (!(i = arc_instance_from_hdr(al))) return US"instance find"; | |
391 | if (!(as = arc_find_set(ctx, i))) return US"set find"; | |
392 | if (*(alp = (arc_line **)(US as + hoff))) return US"dup hdr"; | |
393 | ||
394 | *alp = al; | |
395 | return NULL; | |
396 | } | |
397 | ||
398 | ||
399 | ||
400 | ||
401 | static const uschar * | |
402 | arc_try_header(arc_ctx * ctx, header_line * h, BOOL instance_only) | |
403 | { | |
404 | const uschar * e; | |
405 | ||
406 | /*debug_printf("consider hdr '%s'\n", h->text);*/ | |
407 | if (strncmpic(ARC_HDR_AAR, h->text, ARC_HDRLEN_AAR) == 0) | |
408 | { | |
409 | DEBUG(D_acl) | |
410 | { | |
411 | int len = h->slen; | |
412 | uschar * s; | |
413 | for (s = h->text + h->slen; s[-1] == '\r' || s[-1] == '\n'; ) | |
414 | s--, len--; | |
415 | debug_printf("ARC: found AAR: %.*s\n", len, h->text); | |
416 | } | |
417 | if ((e = arc_insert_hdr(ctx, h, ARC_HDRLEN_AAR, offsetof(arc_set, hdr_aar), | |
418 | TRUE))) | |
419 | { | |
420 | DEBUG(D_acl) debug_printf("inserting AAR: %s\n", e); | |
421 | return US"inserting AAR"; | |
422 | } | |
423 | } | |
424 | else if (strncmpic(ARC_HDR_AMS, h->text, ARC_HDRLEN_AMS) == 0) | |
425 | { | |
426 | arc_line * ams; | |
427 | ||
428 | DEBUG(D_acl) | |
429 | { | |
430 | int len = h->slen; | |
431 | uschar * s; | |
432 | for (s = h->text + h->slen; s[-1] == '\r' || s[-1] == '\n'; ) | |
433 | s--, len--; | |
434 | debug_printf("ARC: found AMS: %.*s\n", len, h->text); | |
435 | } | |
436 | if ((e = arc_insert_hdr(ctx, h, ARC_HDRLEN_AMS, offsetof(arc_set, hdr_ams), | |
437 | instance_only))) | |
438 | { | |
439 | DEBUG(D_acl) debug_printf("inserting AMS: %s\n", e); | |
440 | return US"inserting AMS"; | |
441 | } | |
442 | ||
443 | /* defaults */ | |
444 | /*XXX dubious selection of ams here */ | |
445 | ams = ctx->arcset_chain->hdr_ams; | |
446 | if (!ams->c.data) | |
447 | { | |
448 | ams->c_head.data = US"simple"; ams->c_head.len = 6; | |
449 | ams->c_body = ams->c_head; | |
450 | } | |
451 | } | |
452 | else if (strncmpic(ARC_HDR_AS, h->text, ARC_HDRLEN_AS) == 0) | |
453 | { | |
454 | DEBUG(D_acl) | |
455 | { | |
456 | int len = h->slen; | |
457 | uschar * s; | |
458 | for (s = h->text + h->slen; s[-1] == '\r' || s[-1] == '\n'; ) | |
459 | s--, len--; | |
460 | debug_printf("ARC: found AS: %.*s\n", len, h->text); | |
461 | } | |
462 | if ((e = arc_insert_hdr(ctx, h, ARC_HDRLEN_AS, offsetof(arc_set, hdr_as), | |
463 | instance_only))) | |
464 | { | |
465 | DEBUG(D_acl) debug_printf("inserting AS: %s\n", e); | |
466 | return US"inserting AS"; | |
467 | } | |
468 | } | |
469 | return NULL; | |
470 | } | |
471 | ||
472 | ||
473 | ||
474 | /* Gather the chain of arc sets from the headers. | |
475 | Check for duplicates while that is done. Also build the | |
476 | reverse-order headers list; | |
477 | ||
478 | Return: ARC state if determined, eg. by lack of any ARC chain. | |
479 | */ | |
480 | ||
481 | static const uschar * | |
482 | arc_vfy_collect_hdrs(arc_ctx * ctx) | |
483 | { | |
484 | header_line * h; | |
978e78de | 485 | hdr_rlist * r = NULL, * rprev = NULL; |
617d3932 JH |
486 | const uschar * e; |
487 | ||
488 | DEBUG(D_acl) debug_printf("ARC: collecting arc sets\n"); | |
489 | for (h = header_list; h; h = h->next) | |
490 | { | |
491 | r = store_get(sizeof(hdr_rlist)); | |
492 | r->prev = rprev; | |
493 | r->used = FALSE; | |
494 | r->h = h; | |
495 | rprev = r; | |
496 | ||
497 | if ((e = arc_try_header(ctx, h, FALSE))) | |
93c931f8 JH |
498 | { |
499 | arc_state_reason = string_sprintf("collecting headers: %s", e); | |
500 | return US"fail"; | |
501 | } | |
617d3932 JH |
502 | } |
503 | headers_rlist = r; | |
504 | ||
505 | if (!ctx->arcset_chain) return US"none"; | |
506 | return NULL; | |
507 | } | |
508 | ||
509 | ||
510 | static BOOL | |
511 | arc_cv_match(arc_line * al, const uschar * s) | |
512 | { | |
513 | return Ustrncmp(s, al->cv.data, al->cv.len) == 0; | |
514 | } | |
515 | ||
516 | /******************************************************************************/ | |
517 | ||
518 | /* Return the hash of headers from the message that the AMS claims it | |
519 | signed. | |
520 | */ | |
521 | ||
522 | static void | |
523 | arc_get_verify_hhash(arc_ctx * ctx, arc_line * ams, blob * hhash) | |
524 | { | |
525 | const uschar * headernames = string_copyn(ams->h.data, ams->h.len); | |
526 | const uschar * hn; | |
527 | int sep = ':'; | |
528 | hdr_rlist * r; | |
529 | BOOL relaxed = Ustrncmp(US"relaxed", ams->c_head.data, ams->c_head.len) == 0; | |
530 | int hashtype = pdkim_hashname_to_hashtype( | |
531 | ams->a_hash.data, ams->a_hash.len); | |
532 | hctx hhash_ctx; | |
533 | const uschar * s; | |
534 | int len; | |
535 | ||
536 | if (!exim_sha_init(&hhash_ctx, pdkim_hashes[hashtype].exim_hashmethod)) | |
537 | { | |
538 | DEBUG(D_acl) | |
539 | debug_printf("ARC: hash setup error, possibly nonhandled hashtype\n"); | |
540 | return; | |
541 | } | |
542 | ||
543 | /* For each headername in the list from the AMS (walking in order) | |
544 | walk the message headers in reverse order, adding to the hash any | |
545 | found for the first time. For that last point, maintain used-marks | |
546 | on the list of message headers. */ | |
547 | ||
548 | DEBUG(D_acl) debug_printf("ARC: AMS header data for verification:\n"); | |
549 | ||
550 | for (r = headers_rlist; r; r = r->prev) | |
551 | r->used = FALSE; | |
552 | while ((hn = string_nextinlist(&headernames, &sep, NULL, 0))) | |
553 | for (r = headers_rlist; r; r = r->prev) | |
554 | if ( !r->used | |
555 | && strncasecmp(CCS (s = r->h->text), CCS hn, Ustrlen(hn)) == 0 | |
556 | ) | |
557 | { | |
558 | if (relaxed) s = pdkim_relax_header_n(s, r->h->slen, TRUE); | |
559 | ||
560 | len = Ustrlen(s); | |
561 | DEBUG(D_acl) pdkim_quoteprint(s, len); | |
562 | exim_sha_update(&hhash_ctx, s, Ustrlen(s)); | |
563 | r->used = TRUE; | |
564 | break; | |
565 | } | |
566 | ||
d64f2515 | 567 | /* Finally add in the signature header (with the b= tag stripped); no CRLF */ |
617d3932 JH |
568 | |
569 | s = ams->rawsig_no_b_val.data, len = ams->rawsig_no_b_val.len; | |
570 | if (relaxed) | |
d64f2515 | 571 | len = Ustrlen(s = pdkim_relax_header_n(s, len, FALSE)); |
617d3932 JH |
572 | DEBUG(D_acl) pdkim_quoteprint(s, len); |
573 | exim_sha_update(&hhash_ctx, s, len); | |
574 | ||
575 | exim_sha_finish(&hhash_ctx, hhash); | |
576 | DEBUG(D_acl) | |
577 | { debug_printf("ARC: header hash: "); pdkim_hexprint(hhash->data, hhash->len); } | |
578 | return; | |
579 | } | |
580 | ||
581 | ||
582 | ||
583 | ||
584 | static pdkim_pubkey * | |
585 | arc_line_to_pubkey(arc_line * al) | |
586 | { | |
587 | uschar * dns_txt; | |
588 | pdkim_pubkey * p; | |
589 | ||
590 | if (!(dns_txt = dkim_exim_query_dns_txt(string_sprintf("%.*s._domainkey.%.*s", | |
591 | al->s.len, al->s.data, al->d.len, al->d.data)))) | |
592 | { | |
593 | DEBUG(D_acl) debug_printf("pubkey dns lookup fail\n"); | |
594 | return NULL; | |
595 | } | |
596 | ||
597 | if ( !(p = pdkim_parse_pubkey_record(dns_txt)) | |
598 | || (Ustrcmp(p->srvtype, "*") != 0 && Ustrcmp(p->srvtype, "email") != 0) | |
599 | ) | |
600 | { | |
601 | DEBUG(D_acl) debug_printf("pubkey dns lookup format error\n"); | |
602 | return NULL; | |
603 | } | |
604 | ||
605 | /* If the pubkey limits use to specified hashes, reject unusable | |
606 | signatures. XXX should we have looked for multiple dns records? */ | |
607 | ||
608 | if (p->hashes) | |
609 | { | |
610 | const uschar * list = p->hashes, * ele; | |
611 | int sep = ':'; | |
612 | ||
613 | while ((ele = string_nextinlist(&list, &sep, NULL, 0))) | |
614 | if (Ustrncmp(ele, al->a_hash.data, al->a_hash.len) == 0) break; | |
615 | if (!ele) | |
616 | { | |
617 | DEBUG(D_acl) debug_printf("pubkey h=%s vs sig a=%.*s\n", | |
978e78de | 618 | p->hashes, (int)al->a.len, al->a.data); |
617d3932 JH |
619 | return NULL; |
620 | } | |
621 | } | |
622 | return p; | |
623 | } | |
624 | ||
625 | ||
626 | ||
627 | ||
628 | static pdkim_bodyhash * | |
629 | arc_ams_setup_vfy_bodyhash(arc_line * ams) | |
630 | { | |
631 | int canon_head, canon_body; | |
632 | long bodylen; | |
633 | ||
dde9989b | 634 | if (!ams->c.data) ams->c.data = US"simple"; /* RFC 6376 (DKIM) default */ |
617d3932 JH |
635 | pdkim_cstring_to_canons(ams->c.data, ams->c.len, &canon_head, &canon_body); |
636 | bodylen = ams->l.data | |
637 | ? strtol(CS string_copyn(ams->l.data, ams->l.len), NULL, 10) : -1; | |
638 | ||
639 | return pdkim_set_bodyhash(dkim_verify_ctx, | |
640 | pdkim_hashname_to_hashtype(ams->a_hash.data, ams->a_hash.len), | |
641 | canon_body, | |
642 | bodylen); | |
643 | } | |
644 | ||
645 | ||
646 | ||
647 | /* Verify an AMS. This is a DKIM-sig header, but with an ARC i= tag | |
648 | and without a DKIM v= tag. | |
649 | */ | |
650 | ||
93c931f8 | 651 | static const uschar * |
617d3932 JH |
652 | arc_ams_verify(arc_ctx * ctx, arc_set * as) |
653 | { | |
654 | arc_line * ams = as->hdr_ams; | |
655 | pdkim_bodyhash * b; | |
656 | pdkim_pubkey * p; | |
657 | blob sighash; | |
658 | blob hhash; | |
659 | ev_ctx vctx; | |
660 | int hashtype; | |
661 | const uschar * errstr; | |
662 | ||
93c931f8 | 663 | as->ams_verify_done = US"in-progress"; |
617d3932 JH |
664 | |
665 | /* Check the AMS has all the required tags: | |
666 | "a=" algorithm | |
667 | "b=" signature | |
668 | "bh=" body hash | |
669 | "d=" domain (for key lookup) | |
670 | "h=" headers (included in signature) | |
671 | "s=" key-selector (for key lookup) | |
672 | */ | |
673 | if ( !ams->a.data || !ams->b.data || !ams->bh.data || !ams->d.data | |
674 | || !ams->h.data || !ams->s.data) | |
93c931f8 JH |
675 | { |
676 | as->ams_verify_done = arc_state_reason = US"required tag missing"; | |
617d3932 | 677 | return US"fail"; |
93c931f8 | 678 | } |
617d3932 JH |
679 | |
680 | ||
681 | /* The bodyhash should have been created earlier, and the dkim code should | |
682 | have managed calculating it during message input. Find the reference to it. */ | |
683 | ||
684 | if (!(b = arc_ams_setup_vfy_bodyhash(ams))) | |
93c931f8 JH |
685 | { |
686 | as->ams_verify_done = arc_state_reason = US"internal hash setup error"; | |
617d3932 | 687 | return US"fail"; |
93c931f8 | 688 | } |
617d3932 JH |
689 | |
690 | DEBUG(D_acl) | |
691 | { | |
692 | debug_printf("ARC i=%d AMS Body bytes hashed: %lu\n" | |
693 | " Body %.*s computed: ", | |
694 | as->instance, b->signed_body_bytes, | |
978e78de | 695 | (int)ams->a_hash.len, ams->a_hash.data); |
617d3932 JH |
696 | pdkim_hexprint(CUS b->bh.data, b->bh.len); |
697 | } | |
698 | ||
699 | /* We know the bh-tag blob is of a nul-term string, so safe as a string */ | |
700 | ||
701 | if ( !ams->bh.data | |
702 | || (pdkim_decode_base64(ams->bh.data, &sighash), sighash.len != b->bh.len) | |
703 | || memcmp(sighash.data, b->bh.data, b->bh.len) != 0 | |
704 | ) | |
705 | { | |
706 | DEBUG(D_acl) | |
707 | { | |
708 | debug_printf("ARC i=%d AMS Body hash from headers: ", as->instance); | |
709 | pdkim_hexprint(sighash.data, sighash.len); | |
710 | debug_printf("ARC i=%d AMS Body hash did NOT match\n", as->instance); | |
711 | } | |
93c931f8 | 712 | return as->ams_verify_done = arc_state_reason = US"AMS body hash miscompare"; |
617d3932 JH |
713 | } |
714 | ||
715 | DEBUG(D_acl) debug_printf("ARC i=%d AMS Body hash compared OK\n", as->instance); | |
716 | ||
717 | /* Get the public key from DNS */ | |
718 | ||
719 | if (!(p = arc_line_to_pubkey(ams))) | |
93c931f8 | 720 | return as->ams_verify_done = arc_state_reason = US"pubkey problem"; |
617d3932 JH |
721 | |
722 | /* We know the b-tag blob is of a nul-term string, so safe as a string */ | |
723 | pdkim_decode_base64(ams->b.data, &sighash); | |
724 | ||
725 | arc_get_verify_hhash(ctx, ams, &hhash); | |
726 | ||
727 | /* Setup the interface to the signing library */ | |
728 | ||
729 | if ((errstr = exim_dkim_verify_init(&p->key, KEYFMT_DER, &vctx))) | |
730 | { | |
731 | DEBUG(D_acl) debug_printf("ARC verify init: %s\n", errstr); | |
93c931f8 | 732 | as->ams_verify_done = arc_state_reason = US"internal sigverify init error"; |
617d3932 JH |
733 | return US"fail"; |
734 | } | |
735 | ||
736 | hashtype = pdkim_hashname_to_hashtype(ams->a_hash.data, ams->a_hash.len); | |
737 | ||
738 | if ((errstr = exim_dkim_verify(&vctx, | |
739 | pdkim_hashes[hashtype].exim_hashmethod, &hhash, &sighash))) | |
740 | { | |
741 | DEBUG(D_acl) debug_printf("ARC i=%d AMS verify %s\n", as->instance, errstr); | |
93c931f8 | 742 | return as->ams_verify_done = arc_state_reason = US"AMS sig nonverify"; |
617d3932 JH |
743 | } |
744 | ||
745 | DEBUG(D_acl) debug_printf("ARC i=%d AMS verify pass\n", as->instance); | |
746 | as->ams_verify_passed = TRUE; | |
747 | return NULL; | |
748 | } | |
749 | ||
750 | ||
751 | ||
752 | /* Check the sets are instance-continuous and that all | |
753 | members are present. Check that no arc_seals are "fail". | |
754 | Set the highest instance number global. | |
755 | Verify the latest AMS. | |
756 | */ | |
757 | static uschar * | |
758 | arc_headers_check(arc_ctx * ctx) | |
759 | { | |
760 | arc_set * as; | |
761 | int inst; | |
762 | BOOL ams_fail_found = FALSE; | |
763 | uschar * ret = NULL; | |
764 | ||
765 | if (!(as = ctx->arcset_chain)) | |
766 | return US"none"; | |
767 | ||
768 | for(inst = 0; as; as = as->next) | |
769 | { | |
770 | if ( as->instance != ++inst | |
771 | || !as->hdr_aar || !as->hdr_ams || !as->hdr_as | |
772 | || arc_cv_match(as->hdr_as, US"fail") | |
773 | ) | |
774 | { | |
dde9989b | 775 | arc_state_reason = string_sprintf("i=%d" |
93c931f8 | 776 | " (cv, sequence or missing header)", as->instance); |
dde9989b JH |
777 | DEBUG(D_acl) debug_printf("ARC chain fail at %s\n", arc_state_reason); |
778 | return US"fail"; | |
617d3932 JH |
779 | } |
780 | ||
781 | /* Evaluate the oldest-pass AMS validation while we're here. | |
782 | It does not affect the AS chain validation but is reported as | |
783 | auxilary info. */ | |
784 | ||
785 | if (!ams_fail_found) | |
786 | if (arc_ams_verify(ctx, as)) | |
787 | ams_fail_found = TRUE; | |
788 | else | |
789 | arc_oldest_pass = inst; | |
93c931f8 | 790 | arc_state_reason = NULL; |
617d3932 JH |
791 | } |
792 | ||
793 | arc_received = ctx->arcset_chain_last; | |
794 | arc_received_instance = inst; | |
795 | if (ret) | |
796 | return ret; | |
797 | ||
798 | /* We can skip the latest-AMS validation, if we already did it. */ | |
799 | ||
800 | as = ctx->arcset_chain_last; | |
93c931f8 JH |
801 | if (as->ams_verify_done && !as->ams_verify_passed) |
802 | { | |
803 | arc_state_reason = as->ams_verify_done; | |
804 | return US"fail"; | |
805 | } | |
806 | if (!!arc_ams_verify(ctx, as)) | |
617d3932 JH |
807 | return US"fail"; |
808 | ||
809 | return NULL; | |
810 | } | |
811 | ||
812 | ||
813 | /******************************************************************************/ | |
814 | static const uschar * | |
815 | arc_seal_verify(arc_ctx * ctx, arc_set * as) | |
816 | { | |
817 | arc_line * hdr_as = as->hdr_as; | |
818 | arc_set * as2; | |
819 | int hashtype; | |
820 | hctx hhash_ctx; | |
821 | blob hhash_computed; | |
822 | blob sighash; | |
823 | ev_ctx vctx; | |
824 | pdkim_pubkey * p; | |
825 | const uschar * errstr; | |
826 | ||
827 | DEBUG(D_acl) debug_printf("ARC: AS vfy i=%d\n", as->instance); | |
828 | /* | |
829 | 1. If the value of the "cv" tag on that seal is "fail", the | |
830 | chain state is "fail" and the algorithm stops here. (This | |
831 | step SHOULD be skipped if the earlier step (2.1) was | |
832 | performed) [it was] | |
833 | ||
834 | 2. In Boolean nomenclature: if ((i == 1 && cv != "none") or (cv | |
835 | == "none" && i != 1)) then the chain state is "fail" and the | |
836 | algorithm stops here (note that the ordering of the logic is | |
837 | structured for short-circuit evaluation). | |
838 | */ | |
839 | ||
840 | if ( as->instance == 1 && !arc_cv_match(hdr_as, US"none") | |
841 | || arc_cv_match(hdr_as, US"none") && as->instance != 1 | |
842 | ) | |
93c931f8 JH |
843 | { |
844 | arc_state_reason = US"seal cv state"; | |
617d3932 | 845 | return US"fail"; |
93c931f8 | 846 | } |
617d3932 JH |
847 | |
848 | /* | |
849 | 3. Initialize a hash function corresponding to the "a" tag of | |
850 | the ARC-Seal. | |
851 | */ | |
852 | ||
853 | hashtype = pdkim_hashname_to_hashtype(hdr_as->a_hash.data, hdr_as->a_hash.len); | |
854 | ||
855 | if (!exim_sha_init(&hhash_ctx, pdkim_hashes[hashtype].exim_hashmethod)) | |
856 | { | |
857 | DEBUG(D_acl) | |
858 | debug_printf("ARC: hash setup error, possibly nonhandled hashtype\n"); | |
93c931f8 | 859 | arc_state_reason = US"seal hash setup error"; |
617d3932 JH |
860 | return US"fail"; |
861 | } | |
862 | ||
863 | /* | |
864 | 4. Compute the canonicalized form of the ARC header fields, in | |
865 | the order described in Section 5.4.2, using the "relaxed" | |
866 | header canonicalization defined in Section 3.4.2 of | |
867 | [RFC6376]. Pass the canonicalized result to the hash | |
868 | function. | |
d64f2515 JH |
869 | |
870 | Headers are CRLF-separated, but the last one is not crlf-terminated. | |
617d3932 JH |
871 | */ |
872 | ||
873 | DEBUG(D_acl) debug_printf("ARC: AS header data for verification:\n"); | |
874 | for (as2 = ctx->arcset_chain; | |
875 | as2 && as2->instance <= as->instance; | |
876 | as2 = as2->next) | |
877 | { | |
878 | arc_line * al; | |
879 | uschar * s; | |
880 | int len; | |
881 | ||
882 | al = as2->hdr_aar; | |
883 | if (!(s = al->relaxed)) | |
884 | al->relaxed = s = pdkim_relax_header_n(al->complete->text, | |
885 | al->complete->slen, TRUE); | |
886 | len = Ustrlen(s); | |
887 | DEBUG(D_acl) pdkim_quoteprint(s, len); | |
888 | exim_sha_update(&hhash_ctx, s, len); | |
889 | ||
890 | al = as2->hdr_ams; | |
891 | if (!(s = al->relaxed)) | |
892 | al->relaxed = s = pdkim_relax_header_n(al->complete->text, | |
893 | al->complete->slen, TRUE); | |
894 | len = Ustrlen(s); | |
895 | DEBUG(D_acl) pdkim_quoteprint(s, len); | |
896 | exim_sha_update(&hhash_ctx, s, len); | |
897 | ||
898 | al = as2->hdr_as; | |
899 | if (as2->instance == as->instance) | |
900 | s = pdkim_relax_header_n(al->rawsig_no_b_val.data, | |
d64f2515 | 901 | al->rawsig_no_b_val.len, FALSE); |
617d3932 JH |
902 | else if (!(s = al->relaxed)) |
903 | al->relaxed = s = pdkim_relax_header_n(al->complete->text, | |
904 | al->complete->slen, TRUE); | |
905 | len = Ustrlen(s); | |
906 | DEBUG(D_acl) pdkim_quoteprint(s, len); | |
907 | exim_sha_update(&hhash_ctx, s, len); | |
908 | } | |
909 | ||
910 | /* | |
911 | 5. Retrieve the final digest from the hash function. | |
912 | */ | |
913 | ||
914 | exim_sha_finish(&hhash_ctx, &hhash_computed); | |
915 | DEBUG(D_acl) | |
916 | { | |
917 | debug_printf("ARC i=%d AS Header %.*s computed: ", | |
978e78de | 918 | as->instance, (int)hdr_as->a_hash.len, hdr_as->a_hash.data); |
617d3932 JH |
919 | pdkim_hexprint(hhash_computed.data, hhash_computed.len); |
920 | } | |
921 | ||
922 | ||
923 | /* | |
924 | 6. Retrieve the public key identified by the "s" and "d" tags in | |
925 | the ARC-Seal, as described in Section 4.1.6. | |
926 | */ | |
927 | ||
928 | if (!(p = arc_line_to_pubkey(hdr_as))) | |
929 | return US"pubkey problem"; | |
930 | ||
931 | /* | |
932 | 7. Determine whether the signature portion ("b" tag) of the ARC- | |
933 | Seal and the digest computed above are valid according to the | |
934 | public key. (See also Section Section 8.4 for failure case | |
935 | handling) | |
936 | ||
937 | 8. If the signature is not valid, the chain state is "fail" and | |
938 | the algorithm stops here. | |
939 | */ | |
940 | ||
941 | /* We know the b-tag blob is of a nul-term string, so safe as a string */ | |
942 | pdkim_decode_base64(hdr_as->b.data, &sighash); | |
943 | ||
944 | if ((errstr = exim_dkim_verify_init(&p->key, KEYFMT_DER, &vctx))) | |
945 | { | |
946 | DEBUG(D_acl) debug_printf("ARC verify init: %s\n", errstr); | |
947 | return US"fail"; | |
948 | } | |
949 | ||
950 | hashtype = pdkim_hashname_to_hashtype(hdr_as->a_hash.data, hdr_as->a_hash.len); | |
951 | ||
952 | if ((errstr = exim_dkim_verify(&vctx, | |
953 | pdkim_hashes[hashtype].exim_hashmethod, | |
954 | &hhash_computed, &sighash))) | |
955 | { | |
956 | DEBUG(D_acl) | |
957 | debug_printf("ARC i=%d AS headers verify: %s\n", as->instance, errstr); | |
d64f2515 | 958 | arc_state_reason = US"seal sigverify error"; |
617d3932 JH |
959 | return US"fail"; |
960 | } | |
961 | ||
962 | DEBUG(D_acl) debug_printf("ARC: AS vfy i=%d pass\n", as->instance); | |
963 | return NULL; | |
964 | } | |
965 | ||
966 | ||
967 | static const uschar * | |
968 | arc_verify_seals(arc_ctx * ctx) | |
969 | { | |
970 | arc_set * as = ctx->arcset_chain; | |
971 | ||
972 | if (!as) | |
973 | return US"none"; | |
974 | ||
975 | while (as) | |
976 | { | |
977 | if (arc_seal_verify(ctx, as)) return US"fail"; | |
978 | as = as->next; | |
979 | } | |
980 | DEBUG(D_acl) debug_printf("ARC: AS vfy overall pass\n"); | |
981 | return NULL; | |
982 | } | |
983 | /******************************************************************************/ | |
984 | ||
985 | /* Do ARC verification. Called from DATA ACL, on a verify = arc | |
986 | condition. No arguments; we are checking globals. | |
987 | ||
988 | Return: The ARC state, or NULL on error. | |
989 | */ | |
990 | ||
991 | const uschar * | |
992 | acl_verify_arc(void) | |
993 | { | |
994 | arc_ctx ctx = { NULL }; | |
995 | const uschar * res; | |
996 | ||
0ed25f66 JH |
997 | if (!dkim_verify_ctx) |
998 | { | |
999 | DEBUG(D_acl) debug_printf("ARC: no DKIM verify context\n"); | |
1000 | return NULL; | |
1001 | } | |
1002 | ||
617d3932 JH |
1003 | /* AS evaluation, per |
1004 | https://tools.ietf.org/html/draft-ietf-dmarc-arc-protocol-10#section-6 | |
1005 | */ | |
1006 | /* 1. Collect all ARC sets currently on the message. If there were | |
1007 | none, the ARC state is "none" and the algorithm stops here. | |
1008 | */ | |
1009 | ||
1010 | if ((res = arc_vfy_collect_hdrs(&ctx))) | |
1011 | goto out; | |
1012 | ||
1013 | /* 2. If the form of any ARC set is invalid (e.g., does not contain | |
1014 | exactly one of each of the three ARC-specific header fields), | |
1015 | then the chain state is "fail" and the algorithm stops here. | |
1016 | ||
1017 | 1. To avoid the overhead of unnecessary computation and delay | |
1018 | from crypto and DNS operations, the cv value for all ARC- | |
1019 | Seal(s) MAY be checked at this point. If any of the values | |
1020 | are "fail", then the overall state of the chain is "fail" and | |
1021 | the algorithm stops here. | |
1022 | ||
1023 | 3. Conduct verification of the ARC-Message-Signature header field | |
1024 | bearing the highest instance number. If this verification fails, | |
1025 | then the chain state is "fail" and the algorithm stops here. | |
1026 | */ | |
1027 | ||
1028 | if ((res = arc_headers_check(&ctx))) | |
1029 | goto out; | |
1030 | ||
1031 | /* 4. For each ARC-Seal from the "N"th instance to the first, apply the | |
1032 | following logic: | |
1033 | ||
1034 | 1. If the value of the "cv" tag on that seal is "fail", the | |
1035 | chain state is "fail" and the algorithm stops here. (This | |
1036 | step SHOULD be skipped if the earlier step (2.1) was | |
1037 | performed) | |
1038 | ||
1039 | 2. In Boolean nomenclature: if ((i == 1 && cv != "none") or (cv | |
1040 | == "none" && i != 1)) then the chain state is "fail" and the | |
1041 | algorithm stops here (note that the ordering of the logic is | |
1042 | structured for short-circuit evaluation). | |
1043 | ||
1044 | 3. Initialize a hash function corresponding to the "a" tag of | |
1045 | the ARC-Seal. | |
1046 | ||
1047 | 4. Compute the canonicalized form of the ARC header fields, in | |
1048 | the order described in Section 5.4.2, using the "relaxed" | |
1049 | header canonicalization defined in Section 3.4.2 of | |
1050 | [RFC6376]. Pass the canonicalized result to the hash | |
1051 | function. | |
1052 | ||
1053 | 5. Retrieve the final digest from the hash function. | |
1054 | ||
1055 | 6. Retrieve the public key identified by the "s" and "d" tags in | |
1056 | the ARC-Seal, as described in Section 4.1.6. | |
1057 | ||
1058 | 7. Determine whether the signature portion ("b" tag) of the ARC- | |
1059 | Seal and the digest computed above are valid according to the | |
1060 | public key. (See also Section Section 8.4 for failure case | |
1061 | handling) | |
1062 | ||
1063 | 8. If the signature is not valid, the chain state is "fail" and | |
1064 | the algorithm stops here. | |
1065 | ||
1066 | 5. If all seals pass validation, then the chain state is "pass", and | |
1067 | the algorithm is complete. | |
1068 | */ | |
1069 | ||
1070 | if ((res = arc_verify_seals(&ctx))) | |
1071 | goto out; | |
1072 | ||
1073 | res = US"pass"; | |
1074 | ||
1075 | out: | |
1076 | return res; | |
1077 | } | |
1078 | ||
1079 | /******************************************************************************/ | |
1080 | ||
1081 | /* Prepend the header to the rlist */ | |
1082 | ||
1083 | static hdr_rlist * | |
1084 | arc_rlist_entry(hdr_rlist * list, const uschar * s, int len) | |
1085 | { | |
1086 | hdr_rlist * r = store_get(sizeof(hdr_rlist) + sizeof(header_line)); | |
1087 | header_line * h = r->h = (header_line *)(r+1); | |
1088 | ||
1089 | r->prev = list; | |
1090 | r->used = FALSE; | |
1091 | h->next = NULL; | |
1092 | h->type = 0; | |
1093 | h->slen = len; | |
1094 | h->text = US s; | |
1095 | ||
1096 | /* This works for either NL or CRLF lines; also nul-termination */ | |
1097 | while (*++s) | |
1098 | if (*s == '\n' && s[1] != '\t' && s[1] != ' ') break; | |
1099 | s++; /* move past end of line */ | |
1100 | ||
1101 | return r; | |
1102 | } | |
1103 | ||
1104 | ||
1105 | /* Walk the given headers strings identifying each header, and construct | |
dde9989b | 1106 | a reverse-order list. |
617d3932 JH |
1107 | */ |
1108 | ||
1109 | static hdr_rlist * | |
1110 | arc_sign_scan_headers(arc_ctx * ctx, gstring * sigheaders) | |
1111 | { | |
1112 | const uschar * s; | |
1113 | hdr_rlist * rheaders = NULL; | |
1114 | ||
1115 | s = sigheaders ? sigheaders->s : NULL; | |
1116 | if (s) while (*s) | |
1117 | { | |
978e78de | 1118 | const uschar * s2 = s; |
617d3932 JH |
1119 | |
1120 | /* This works for either NL or CRLF lines; also nul-termination */ | |
1121 | while (*++s2) | |
1122 | if (*s2 == '\n' && s2[1] != '\t' && s2[1] != ' ') break; | |
1123 | s2++; /* move past end of line */ | |
1124 | ||
1125 | rheaders = arc_rlist_entry(rheaders, s, s2 - s); | |
1126 | s = s2; | |
1127 | } | |
1128 | return rheaders; | |
1129 | } | |
1130 | ||
1131 | ||
1132 | ||
1133 | /* Return the A-R content, without identity, with line-ending and | |
1134 | NUL termination. */ | |
1135 | ||
1136 | static BOOL | |
1137 | arc_sign_find_ar(header_line * headers, const uschar * identity, blob * ret) | |
1138 | { | |
1139 | header_line * h; | |
1140 | int ilen = Ustrlen(identity); | |
1141 | ||
1142 | ret->data = NULL; | |
1143 | for(h = headers; h; h = h->next) | |
1144 | { | |
1145 | uschar * s = h->text, c; | |
1146 | int len = h->slen; | |
1147 | ||
1148 | if (Ustrncmp(s, HDR_AR, HDRLEN_AR) != 0) continue; | |
1149 | s += HDRLEN_AR, len -= HDRLEN_AR; /* header name */ | |
1150 | while ( len > 0 | |
1151 | && (c = *s) && (c == ' ' || c == '\t' || c == '\r' || c == '\n')) | |
1152 | s++, len--; /* FWS */ | |
1153 | if (Ustrncmp(s, identity, ilen) != 0) continue; | |
1154 | s += ilen; len -= ilen; /* identity */ | |
1155 | if (len <= 0) continue; | |
1156 | if ((c = *s) && c == ';') s++, len--; /* identity terminator */ | |
1157 | while ( len > 0 | |
1158 | && (c = *s) && (c == ' ' || c == '\t' || c == '\r' || c == '\n')) | |
1159 | s++, len--; /* FWS */ | |
1160 | if (len <= 0) continue; | |
1161 | ret->data = s; | |
1162 | ret->len = len; | |
1163 | return TRUE; | |
1164 | } | |
1165 | return FALSE; | |
1166 | } | |
1167 | ||
1168 | ||
1169 | ||
1170 | /* Append a constructed AAR including CRLF. Add it to the arc_ctx too. */ | |
1171 | ||
1172 | static gstring * | |
1173 | arc_sign_append_aar(gstring * g, arc_ctx * ctx, | |
1174 | const uschar * identity, int instance, blob * ar) | |
1175 | { | |
1176 | int aar_off = g ? g->ptr : 0; | |
1177 | arc_set * as = store_get(sizeof(arc_set) + sizeof(arc_line) + sizeof(header_line)); | |
1178 | arc_line * al = (arc_line *)(as+1); | |
1179 | header_line * h = (header_line *)(al+1); | |
1180 | ||
1181 | g = string_catn(g, ARC_HDR_AAR, ARC_HDRLEN_AAR); | |
1182 | g = string_cat(g, string_sprintf(" i=%d; %s;\r\n\t", instance, identity)); | |
1183 | g = string_catn(g, US ar->data, ar->len); | |
1184 | ||
1185 | h->slen = g->ptr - aar_off; | |
1186 | h->text = g->s + aar_off; | |
1187 | al->complete = h; | |
1188 | as->next = NULL; | |
1189 | as->prev = ctx->arcset_chain_last; | |
1190 | as->instance = instance; | |
1191 | as->hdr_aar = al; | |
1192 | if (instance == 1) | |
1193 | ctx->arcset_chain = as; | |
1194 | else | |
1195 | ctx->arcset_chain_last->next = as; | |
1196 | ctx->arcset_chain_last = as; | |
1197 | ||
1198 | DEBUG(D_transport) debug_printf("ARC: AAR '%.*s'\n", h->slen - 2, h->text); | |
1199 | return g; | |
1200 | } | |
1201 | ||
1202 | ||
1203 | ||
1204 | static BOOL | |
1205 | arc_sig_from_pseudoheader(gstring * hdata, int hashtype, const uschar * privkey, | |
1206 | blob * sig, const uschar * why) | |
1207 | { | |
1208 | hashmethod hm = /*sig->keytype == KEYTYPE_ED25519*/ FALSE | |
1209 | ? HASH_SHA2_512 : pdkim_hashes[hashtype].exim_hashmethod; | |
1210 | blob hhash; | |
1211 | es_ctx sctx; | |
1212 | const uschar * errstr; | |
1213 | ||
1214 | DEBUG(D_transport) | |
1215 | { | |
1216 | hctx hhash_ctx; | |
1217 | debug_printf("ARC: %s header data for signing:\n", why); | |
1218 | pdkim_quoteprint(hdata->s, hdata->ptr); | |
1219 | ||
1220 | (void) exim_sha_init(&hhash_ctx, pdkim_hashes[hashtype].exim_hashmethod); | |
1221 | exim_sha_update(&hhash_ctx, hdata->s, hdata->ptr); | |
1222 | exim_sha_finish(&hhash_ctx, &hhash); | |
1223 | debug_printf("ARC: header hash: "); pdkim_hexprint(hhash.data, hhash.len); | |
1224 | } | |
1225 | ||
1226 | if (FALSE /*need hash for Ed25519 or GCrypt signing*/ ) | |
1227 | { | |
1228 | hctx hhash_ctx; | |
1229 | (void) exim_sha_init(&hhash_ctx, pdkim_hashes[hashtype].exim_hashmethod); | |
1230 | exim_sha_update(&hhash_ctx, hdata->s, hdata->ptr); | |
1231 | exim_sha_finish(&hhash_ctx, &hhash); | |
1232 | } | |
1233 | else | |
1234 | { | |
1235 | hhash.data = hdata->s; | |
1236 | hhash.len = hdata->ptr; | |
1237 | } | |
1238 | ||
1239 | if ( (errstr = exim_dkim_signing_init(privkey, &sctx)) | |
1240 | || (errstr = exim_dkim_sign(&sctx, hm, &hhash, sig))) | |
1241 | { | |
1242 | log_write(0, LOG_MAIN|LOG_PANIC, "ARC: %s signing: %s\n", why, errstr); | |
1243 | return FALSE; | |
1244 | } | |
1245 | return TRUE; | |
1246 | } | |
1247 | ||
1248 | ||
1249 | ||
1250 | static gstring * | |
1251 | arc_sign_append_sig(gstring * g, blob * sig) | |
1252 | { | |
1253 | /*debug_printf("%s: raw sig ", __FUNCTION__); pdkim_hexprint(sig->data, sig->len);*/ | |
1254 | sig->data = pdkim_encode_base64(sig); | |
1255 | sig->len = Ustrlen(sig->data); | |
1256 | for (;;) | |
1257 | { | |
1258 | int len = MIN(sig->len, 74); | |
1259 | g = string_catn(g, sig->data, len); | |
1260 | if ((sig->len -= len) == 0) break; | |
1261 | sig->data += len; | |
1262 | g = string_catn(g, US"\r\n\t ", 5); | |
1263 | } | |
1264 | g = string_catn(g, US";\r\n", 3); | |
1265 | gstring_reset_unused(g); | |
1266 | string_from_gstring(g); | |
1267 | return g; | |
1268 | } | |
1269 | ||
1270 | ||
1271 | /* Append a constructed AMS including CRLF. Add it to the arc_ctx too. */ | |
1272 | ||
1273 | static gstring * | |
1274 | arc_sign_append_ams(gstring * g, arc_ctx * ctx, int instance, | |
1275 | const uschar * identity, const uschar * selector, blob * bodyhash, | |
1276 | hdr_rlist * rheaders, const uschar * privkey) | |
1277 | { | |
1278 | uschar * s; | |
1279 | gstring * hdata = NULL; | |
1280 | int col; | |
1281 | int hashtype = pdkim_hashname_to_hashtype(US"sha256", 6); /*XXX hardwired */ | |
1282 | blob sig; | |
1283 | int ams_off; | |
1284 | arc_line * al = store_get(sizeof(header_line) + sizeof(arc_line)); | |
1285 | header_line * h = (header_line *)(al+1); | |
1286 | ||
1287 | /* debug_printf("%s\n", __FUNCTION__); */ | |
1288 | ||
1289 | /* Construct the to-be-signed AMS pseudo-header: everything but the sig. */ | |
1290 | ||
1291 | ams_off = g->ptr; | |
1292 | g = string_append(g, 10, | |
1293 | ARC_HDR_AMS, | |
1294 | US" i=", string_sprintf("%d", instance), | |
1295 | US"; a=rsa-sha256; c=relaxed; d=", identity, /*XXX hardwired */ | |
1296 | US"; s=", selector, | |
1297 | US";\r\n\tbh=", pdkim_encode_base64(bodyhash), | |
1298 | US";\r\n\th="); | |
1299 | ||
1300 | for(col = 3; rheaders; rheaders = rheaders->prev) | |
1301 | { | |
1302 | const uschar * hnames = US"DKIM-Signature:" PDKIM_DEFAULT_SIGN_HEADERS; | |
1303 | uschar * name, * htext = rheaders->h->text; | |
1304 | int sep = ':'; | |
1305 | ||
1306 | /* Spot headers of interest */ | |
1307 | ||
1308 | while ((name = string_nextinlist(&hnames, &sep, NULL, 0))) | |
1309 | { | |
1310 | int len = Ustrlen(name); | |
1311 | if (strncasecmp(CCS htext, CCS name, len) == 0) | |
1312 | { | |
1313 | /* If too long, fold line in h= field */ | |
1314 | ||
1315 | if (col + len > 78) g = string_catn(g, US"\r\n\t ", 5), col = 3; | |
1316 | ||
1317 | /* Add name to h= list */ | |
1318 | ||
1319 | g = string_catn(g, name, len); | |
1320 | g = string_catn(g, US":", 1); | |
1321 | col += len + 1; | |
1322 | ||
1323 | /* Accumulate header for hashing/signing */ | |
1324 | ||
1325 | hdata = string_cat(hdata, | |
1326 | pdkim_relax_header_n(htext, rheaders->h->slen, TRUE)); /*XXX hardwired */ | |
1327 | break; | |
1328 | } | |
1329 | } | |
1330 | } | |
1331 | ||
1332 | /* Lose the last colon from the h= list */ | |
1333 | ||
1334 | if (g->s[g->ptr - 1] == ':') g->ptr--; | |
1335 | ||
1336 | g = string_catn(g, US";\r\n\tb=;", 7); | |
1337 | ||
1338 | /* Include the pseudo-header in the accumulation */ | |
617d3932 | 1339 | |
d64f2515 | 1340 | s = pdkim_relax_header_n(g->s + ams_off, g->ptr - ams_off, FALSE); |
617d3932 JH |
1341 | hdata = string_cat(hdata, s); |
1342 | ||
1343 | /* Calculate the signature from the accumulation */ | |
1344 | /*XXX does that need further relaxation? there are spaces embedded in the b= strings! */ | |
1345 | ||
1346 | if (!arc_sig_from_pseudoheader(hdata, hashtype, privkey, &sig, US"AMS")) | |
1347 | return NULL; | |
1348 | ||
1349 | /* Lose the trailing semicolon from the psuedo-header, and append the signature | |
1350 | (folded over lines) and termination to complete it. */ | |
1351 | ||
1352 | g->ptr--; | |
1353 | g = arc_sign_append_sig(g, &sig); | |
1354 | ||
1355 | h->slen = g->ptr - ams_off; | |
1356 | h->text = g->s + ams_off; | |
1357 | al->complete = h; | |
1358 | ctx->arcset_chain_last->hdr_ams = al; | |
1359 | ||
1360 | DEBUG(D_transport) debug_printf("ARC: AMS '%.*s'\n", h->slen - 2, h->text); | |
1361 | return g; | |
1362 | } | |
1363 | ||
1364 | ||
1365 | ||
1366 | /* Look for an arc= result in an A-R header blob. We know that its data | |
1367 | happens to be a NUL-term string. */ | |
1368 | ||
1369 | static uschar * | |
1370 | arc_ar_cv_status(blob * ar) | |
1371 | { | |
1372 | const uschar * resinfo = ar->data; | |
1373 | int sep = ';'; | |
1374 | uschar * methodspec, * s; | |
1375 | ||
1376 | while ((methodspec = string_nextinlist(&resinfo, &sep, NULL, 0))) | |
1377 | if (Ustrncmp(methodspec, US"arc=", 4) == 0) | |
1378 | { | |
1379 | uschar c; | |
1380 | for (s = methodspec += 4; | |
1381 | (c = *s) && c != ';' && c != ' ' && c != '\r' && c != '\n'; ) s++; | |
1382 | return string_copyn(methodspec, s - methodspec); | |
1383 | } | |
abc01b4f | 1384 | return US"none"; |
617d3932 JH |
1385 | } |
1386 | ||
1387 | ||
1388 | ||
1389 | /* Build the AS header and prepend it */ | |
1390 | ||
1391 | static gstring * | |
1392 | arc_sign_prepend_as(gstring * arcset_interim, arc_ctx * ctx, | |
1393 | int instance, const uschar * identity, const uschar * selector, blob * ar, | |
1394 | const uschar * privkey) | |
1395 | { | |
1396 | gstring * arcset; | |
1397 | arc_set * as; | |
1398 | uschar * status = arc_ar_cv_status(ar); | |
1399 | arc_line * al = store_get(sizeof(header_line) + sizeof(arc_line)); | |
1400 | header_line * h = (header_line *)(al+1); | |
617d3932 JH |
1401 | |
1402 | gstring * hdata = NULL; | |
1403 | int hashtype = pdkim_hashname_to_hashtype(US"sha256", 6); /*XXX hardwired */ | |
1404 | blob sig; | |
1405 | ||
1406 | /* | |
1407 | - Generate AS | |
1408 | - no body coverage | |
1409 | - no h= tag; implicit coverage | |
1410 | - arc status from A-R | |
1411 | - if fail: | |
1412 | - coverage is just the new ARC set | |
1413 | including self (but with an empty b= in self) | |
1414 | - if non-fail: | |
1415 | - all ARC set headers, set-number order, aar then ams then as, | |
1416 | including self (but with an empty b= in self) | |
1417 | */ | |
1418 | ||
1419 | /* Construct the AS except for the signature */ | |
1420 | ||
1421 | arcset = string_append(NULL, 10, | |
1422 | ARC_HDR_AS, | |
1423 | US" i=", string_sprintf("%d", instance), | |
1424 | US"; cv=", status, | |
59066f8f | 1425 | US"; a=rsa-sha256; d=", identity, /*XXX hardwired */ |
617d3932 JH |
1426 | US"; s=", selector, /*XXX same as AMS */ |
1427 | US";\r\n\t b=;"); | |
1428 | ||
1429 | h->slen = arcset->ptr; | |
1430 | h->text = arcset->s; | |
1431 | al->complete = h; | |
1432 | ctx->arcset_chain_last->hdr_as = al; | |
1433 | ||
1434 | /* For any but "fail" chain-verify status, walk the entire chain in order by | |
1435 | instance. For fail, only the new arc-set. Accumulate the elements walked. */ | |
1436 | ||
1437 | for (as = Ustrcmp(status, US"fail") == 0 | |
1438 | ? ctx->arcset_chain_last : ctx->arcset_chain; | |
1439 | as; as = as->next) | |
1440 | { | |
1441 | /* Accumulate AAR then AMS then AS. Relaxed canonicalisation | |
1442 | is required per standard. */ | |
1443 | ||
1444 | h = as->hdr_aar->complete; | |
1445 | hdata = string_cat(hdata, pdkim_relax_header_n(h->text, h->slen, TRUE)); | |
1446 | h = as->hdr_ams->complete; | |
1447 | hdata = string_cat(hdata, pdkim_relax_header_n(h->text, h->slen, TRUE)); | |
1448 | h = as->hdr_as->complete; | |
d64f2515 | 1449 | hdata = string_cat(hdata, pdkim_relax_header_n(h->text, h->slen, !!as->next)); |
617d3932 JH |
1450 | } |
1451 | ||
1452 | /* Calculate the signature from the accumulation */ | |
1453 | ||
1454 | if (!arc_sig_from_pseudoheader(hdata, hashtype, privkey, &sig, US"AS")) | |
1455 | return NULL; | |
1456 | ||
1457 | /* Lose the trailing semicolon */ | |
1458 | arcset->ptr--; | |
1459 | arcset = arc_sign_append_sig(arcset, &sig); | |
1460 | DEBUG(D_transport) debug_printf("ARC: AS '%.*s'\n", arcset->ptr - 2, arcset->s); | |
1461 | ||
1462 | /* Finally, append the AMS and AAR to the new AS */ | |
1463 | ||
1464 | return string_catn(arcset, arcset_interim->s, arcset_interim->ptr); | |
1465 | } | |
1466 | ||
1467 | ||
1468 | /**************************************/ | |
1469 | ||
1470 | /* Return pointer to pdkim_bodyhash for given hash method, creating new | |
1471 | method if needed. | |
1472 | */ | |
1473 | ||
1474 | void * | |
1475 | arc_ams_setup_sign_bodyhash(void) | |
1476 | { | |
1477 | int canon_head, canon_body; | |
1478 | ||
1479 | DEBUG(D_transport) debug_printf("ARC: requesting bodyhash\n"); | |
1480 | pdkim_cstring_to_canons(US"relaxed", 7, &canon_head, &canon_body); /*XXX hardwired */ | |
1481 | return pdkim_set_bodyhash(&dkim_sign_ctx, | |
1482 | pdkim_hashname_to_hashtype(US"sha256", 6), /*XXX hardwired */ | |
1483 | canon_body, | |
1484 | -1); | |
1485 | } | |
1486 | ||
1487 | ||
1488 | ||
dde9989b JH |
1489 | void |
1490 | arc_sign_init(void) | |
1491 | { | |
1492 | memset(&arc_sign_ctx, 0, sizeof(arc_sign_ctx)); | |
1493 | } | |
1494 | ||
1495 | ||
1496 | ||
617d3932 JH |
1497 | /* A "normal" header line, identified by DKIM processing. These arrive before |
1498 | the call to arc_sign(), which carries any newly-created DKIM headers - and | |
1499 | those go textually before the normal ones in the message. | |
1500 | ||
1501 | We have to take the feed from DKIM as, in the transport-filter case, the | |
1502 | headers are not in memory at the time of the call to arc_sign(). | |
1503 | ||
1504 | Take a copy of the header and construct a reverse-order list. | |
1505 | Also parse ARC-chain headers and build the chain struct, retaining pointers | |
1506 | into the copies. | |
1507 | */ | |
1508 | ||
1509 | static const uschar * | |
1510 | arc_header_sign_feed(gstring * g) | |
1511 | { | |
1512 | uschar * s = string_copyn(g->s, g->ptr); | |
1513 | headers_rlist = arc_rlist_entry(headers_rlist, s, g->ptr); | |
1514 | return arc_try_header(&arc_sign_ctx, headers_rlist->h, TRUE); | |
1515 | } | |
1516 | ||
1517 | ||
1518 | ||
1519 | /* ARC signing. Called from the smtp transport, if the arc_sign option is set. | |
1520 | The dkim_exim_sign() function has already been called, so will have hashed the | |
1521 | message body for us so long as we requested a hash previously. | |
1522 | ||
1523 | Arguments: | |
1524 | signspec Three-element colon-sep list: identity, selector, privkey | |
1525 | Already expanded | |
1526 | sigheaders Any signature headers already generated, eg. by DKIM, or NULL | |
1527 | errstr Error string | |
1528 | ||
1529 | Return value | |
1530 | Set of headers to prepend to the message, including the supplied sigheaders | |
1531 | but not the plainheaders. | |
1532 | */ | |
1533 | ||
1534 | gstring * | |
1535 | arc_sign(const uschar * signspec, gstring * sigheaders, uschar ** errstr) | |
1536 | { | |
1537 | const uschar * identity, * selector, * privkey; | |
1538 | int sep = 0; | |
1539 | header_line * headers; | |
1540 | hdr_rlist * rheaders; | |
1541 | blob ar; | |
1542 | int instance; | |
1543 | gstring * g = NULL; | |
1544 | pdkim_bodyhash * b; | |
1545 | ||
1546 | /* Parse the signing specification */ | |
1547 | ||
1548 | identity = string_nextinlist(&signspec, &sep, NULL, 0); | |
1549 | selector = string_nextinlist(&signspec, &sep, NULL, 0); | |
1550 | if ( !*identity | !*selector | |
1551 | || !(privkey = string_nextinlist(&signspec, &sep, NULL, 0)) || !*privkey) | |
1552 | { | |
47dc3814 JH |
1553 | log_write(0, LOG_MAIN|LOG_PANIC, "ARC: bad signing-specification (%s)", |
1554 | !*identity ? "identity" : !*selector ? "selector" : "private-key"); | |
617d3932 JH |
1555 | return NULL; |
1556 | } | |
1557 | if (*privkey == '/' && !(privkey = expand_file_big_buffer(privkey))) | |
1558 | return NULL; | |
1559 | ||
1560 | DEBUG(D_transport) debug_printf("ARC: sign for %s\n", identity); | |
1561 | ||
dde9989b JH |
1562 | /* Make an rlist of any new DKIM headers, then add the "normals" rlist to it. |
1563 | Then scan the list for an A-R header. */ | |
617d3932 JH |
1564 | |
1565 | string_from_gstring(sigheaders); | |
1566 | if ((rheaders = arc_sign_scan_headers(&arc_sign_ctx, sigheaders))) | |
1567 | { | |
1568 | hdr_rlist ** rp; | |
1569 | for (rp = &rheaders; *rp; ) rp = &(*rp)->prev; | |
1570 | *rp = headers_rlist; | |
1571 | headers_rlist = rheaders; | |
1572 | } | |
1573 | else | |
1574 | rheaders = headers_rlist; | |
dde9989b | 1575 | |
617d3932 JH |
1576 | /* Finally, build a normal-order headers list */ |
1577 | /*XXX only needed for hunt-the-AR? */ | |
dde9989b JH |
1578 | { |
1579 | header_line * hnext = NULL; | |
1580 | for (; rheaders; hnext = rheaders->h, rheaders = rheaders->prev) | |
1581 | rheaders->h->next = hnext; | |
1582 | headers = hnext; | |
1583 | } | |
617d3932 JH |
1584 | |
1585 | if (!(arc_sign_find_ar(headers, identity, &ar))) | |
1586 | { | |
1587 | log_write(0, LOG_MAIN|LOG_PANIC, "ARC: no Authentication-Results header for signing"); | |
1588 | return sigheaders ? sigheaders : string_get(0); | |
1589 | } | |
1590 | ||
dde9989b JH |
1591 | /* We previously built the data-struct for the existing ARC chain, if any, using a headers |
1592 | feed from the DKIM module. Use that to give the instance number for the ARC set we are | |
1593 | about to build. */ | |
1594 | ||
1595 | DEBUG(D_transport) | |
1596 | if (arc_sign_ctx.arcset_chain_last) | |
1597 | debug_printf("ARC: existing chain highest instance: %d\n", | |
1598 | arc_sign_ctx.arcset_chain_last->instance); | |
1599 | else | |
1600 | debug_printf("ARC: no existing chain\n"); | |
1601 | ||
1602 | instance = arc_sign_ctx.arcset_chain_last ? arc_sign_ctx.arcset_chain_last->instance + 1 : 1; | |
1603 | ||
617d3932 JH |
1604 | /* |
1605 | - Generate AAR | |
1606 | - copy the A-R; prepend i= & identity | |
1607 | */ | |
1608 | ||
1609 | g = arc_sign_append_aar(g, &arc_sign_ctx, identity, instance, &ar); | |
1610 | ||
1611 | /* | |
1612 | - Generate AMS | |
1613 | - Looks fairly like a DKIM sig | |
1614 | - Cover all DKIM sig headers as well as the usuals | |
1615 | - ? oversigning? | |
1616 | - Covers the data | |
1617 | - we must have requested a suitable bodyhash previously | |
1618 | */ | |
1619 | ||
1620 | b = arc_ams_setup_sign_bodyhash(); | |
1621 | g = arc_sign_append_ams(g, &arc_sign_ctx, instance, identity, selector, | |
1622 | &b->bh, headers_rlist, privkey); | |
1623 | ||
1624 | /* | |
1625 | - Generate AS | |
1626 | - no body coverage | |
1627 | - no h= tag; implicit coverage | |
1628 | - arc status from A-R | |
1629 | - if fail: | |
1630 | - coverage is just the new ARC set | |
1631 | including self (but with an empty b= in self) | |
1632 | - if non-fail: | |
1633 | - all ARC set headers, set-number order, aar then ams then as, | |
1634 | including self (but with an empty b= in self) | |
1635 | */ | |
1636 | ||
1637 | g = arc_sign_prepend_as(g, &arc_sign_ctx, instance, identity, selector, &ar, privkey); | |
1638 | ||
1639 | /* Finally, append the dkim headers and return the lot. */ | |
1640 | ||
1641 | g = string_catn(g, sigheaders->s, sigheaders->ptr); | |
1642 | (void) string_from_gstring(g); | |
1643 | gstring_reset_unused(g); | |
1644 | return g; | |
1645 | } | |
1646 | ||
1647 | ||
1648 | /******************************************************************************/ | |
1649 | ||
1650 | /* Check to see if the line is an AMS and if so, set up to validate it. | |
1651 | Called from the DKIM input processing. This must be done now as the message | |
1652 | body data is hashed during input. | |
1653 | ||
1654 | We call the DKIM code to request a body-hash; it has the facility already | |
1655 | and the hash parameters might be common with other requests. | |
1656 | */ | |
1657 | ||
1658 | static const uschar * | |
1659 | arc_header_vfy_feed(gstring * g) | |
1660 | { | |
1661 | header_line h; | |
1662 | arc_line al; | |
1663 | pdkim_bodyhash * b; | |
1664 | uschar * errstr; | |
1665 | ||
1666 | if (!dkim_verify_ctx) return US"no dkim context"; | |
1667 | ||
1668 | if (strncmpic(ARC_HDR_AMS, g->s, ARC_HDRLEN_AMS) != 0) return US"not AMS"; | |
1669 | ||
1670 | DEBUG(D_receive) debug_printf("ARC: spotted AMS header\n"); | |
1671 | /* Parse the AMS header */ | |
1672 | ||
1673 | h.next = NULL; | |
1674 | h.slen = g->size; | |
1675 | h.text = g->s; | |
1676 | memset(&al, 0, sizeof(arc_line)); | |
1677 | if ((errstr = arc_parse_line(&al, &h, ARC_HDRLEN_AMS, FALSE))) | |
1678 | { | |
1679 | DEBUG(D_acl) if (errstr) debug_printf("ARC: %s\n", errstr); | |
1680 | return US"line parsing error"; | |
1681 | } | |
1682 | ||
1683 | /* defaults */ | |
1684 | if (!al.c.data) | |
1685 | { | |
1686 | al.c_body.data = US"simple"; al.c_body.len = 6; | |
1687 | al.c_head = al.c_body; | |
1688 | } | |
1689 | ||
1690 | /* Ask the dkim code to calc a bodyhash with those specs */ | |
1691 | ||
1692 | if (!(b = arc_ams_setup_vfy_bodyhash(&al))) | |
1693 | return US"dkim hash setup fail"; | |
1694 | ||
1695 | /* Discard the reference; search again at verify time, knowing that one | |
1696 | should have been created here. */ | |
1697 | ||
1698 | return NULL; | |
1699 | } | |
1700 | ||
1701 | ||
1702 | ||
1703 | /* A header line has been identified by DKIM processing. | |
1704 | ||
1705 | Arguments: | |
1706 | g Header line | |
1707 | is_vfy TRUE for verify mode or FALSE for signing mode | |
1708 | ||
1709 | Return: | |
1710 | NULL for success, or an error string (probably unused) | |
1711 | */ | |
1712 | ||
1713 | const uschar * | |
1714 | arc_header_feed(gstring * g, BOOL is_vfy) | |
1715 | { | |
1716 | return is_vfy ? arc_header_vfy_feed(g) : arc_header_sign_feed(g); | |
1717 | } | |
1718 | ||
1719 | ||
1720 | ||
1721 | /******************************************************************************/ | |
1722 | ||
1723 | /* Construct an Authenticate-Results header portion, for the ARC module */ | |
1724 | ||
1725 | gstring * | |
1726 | authres_arc(gstring * g) | |
1727 | { | |
1728 | if (arc_state) | |
1729 | { | |
1730 | arc_line * highest_ams; | |
978e78de | 1731 | int start = 0; /* Compiler quietening */ |
617d3932 JH |
1732 | DEBUG(D_acl) start = g->ptr; |
1733 | ||
1734 | g = string_append(g, 2, US";\n\tarc=", arc_state); | |
1735 | if (arc_received_instance > 0) | |
1736 | { | |
1737 | g = string_append(g, 3, US" (i=", | |
93c931f8 JH |
1738 | string_sprintf("%d", arc_received_instance), US")"); |
1739 | if (arc_state_reason) | |
1740 | g = string_append(g, 3, US"(", arc_state_reason, US")"); | |
1741 | g = string_catn(g, US" header.s=", 10); | |
617d3932 JH |
1742 | highest_ams = arc_received->hdr_ams; |
1743 | g = string_catn(g, highest_ams->s.data, highest_ams->s.len); | |
1744 | ||
1745 | g = string_append(g, 2, | |
1746 | US" arc.oldest-pass=", string_sprintf("%d", arc_oldest_pass)); | |
1747 | ||
1748 | if (sender_host_address) | |
1749 | g = string_append(g, 2, US" smtp.client-ip=", sender_host_address); | |
1750 | } | |
dde9989b JH |
1751 | else if (arc_state_reason) |
1752 | g = string_append(g, 3, US" (", arc_state_reason, US")"); | |
617d3932 JH |
1753 | DEBUG(D_acl) debug_printf("ARC: authres '%.*s'\n", |
1754 | g->ptr - start - 3, g->s + start + 3); | |
1755 | } | |
1756 | else | |
1757 | DEBUG(D_acl) debug_printf("ARC: no authres\n"); | |
1758 | return g; | |
1759 | } | |
1760 | ||
1761 | ||
1762 | # endif /* SUPPORT_SPF */ | |
1763 | #endif /* EXPERIMENTAL_ARC */ | |
1764 | /* vi: aw ai sw=2 | |
1765 | */ |