Commit | Line | Data |
---|---|---|
80a47a2c TK |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
d4e5e70b | 5 | /* Copyright (c) University of Cambridge, 1995 - 2017 */ |
80a47a2c TK |
6 | /* See the file NOTICE for conditions of use and distribution. */ |
7 | ||
8 | /* Code for DKIM support. Other DKIM relevant code is in | |
9 | receive.c, transport.c and transports/smtp.c */ | |
10 | ||
11 | #include "exim.h" | |
12 | ||
13 | #ifndef DISABLE_DKIM | |
14 | ||
970424a5 JH |
15 | # include "pdkim/pdkim.h" |
16 | ||
17 | # ifdef MACRO_PREDEF | |
5f69a529 | 18 | # include "macro_predef.h" |
970424a5 JH |
19 | |
20 | void | |
a2701501 | 21 | params_dkim(void) |
970424a5 JH |
22 | { |
23 | builtin_macro_create_var(US"_DKIM_SIGN_HEADERS", US PDKIM_DEFAULT_SIGN_HEADERS); | |
24 | } | |
25 | # else /*!MACRO_PREDEF*/ | |
26 | ||
27 | ||
28 | ||
80a47a2c | 29 | |
ca9cb170 | 30 | int dkim_verify_oldpool; |
1cfe5c1c | 31 | pdkim_ctx *dkim_verify_ctx = NULL; |
80a47a2c | 32 | pdkim_signature *dkim_signatures = NULL; |
1cfe5c1c | 33 | pdkim_signature *dkim_cur_sig = NULL; |
b9df1829 | 34 | static const uschar * dkim_collect_error = NULL; |
80a47a2c | 35 | |
d73e45df JH |
36 | |
37 | ||
38 | /*XXX the caller only uses the first record if we return multiple. | |
d73e45df JH |
39 | */ |
40 | ||
1eedc10f JH |
41 | static uschar * |
42 | dkim_exim_query_dns_txt(char * name) | |
1cfe5c1c JH |
43 | { |
44 | dns_answer dnsa; | |
45 | dns_scan dnss; | |
46 | dns_record *rr; | |
1eedc10f | 47 | gstring * g = NULL; |
80a47a2c | 48 | |
1cfe5c1c JH |
49 | lookup_dnssec_authenticated = NULL; |
50 | if (dns_lookup(&dnsa, US name, T_TXT, NULL) != DNS_SUCCEED) | |
1eedc10f | 51 | return NULL; /*XXX better error detail? logging? */ |
80a47a2c | 52 | |
1cfe5c1c | 53 | /* Search for TXT record */ |
80a47a2c | 54 | |
1cfe5c1c JH |
55 | for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS); |
56 | rr; | |
57 | rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) | |
58 | if (rr->type == T_TXT) | |
59 | { | |
80a47a2c TK |
60 | int rr_offset = 0; |
61 | int answer_offset = 0; | |
1cfe5c1c JH |
62 | |
63 | /* Copy record content to the answer buffer */ | |
64 | ||
65 | while (rr_offset < rr->size) | |
66 | { | |
67 | uschar len = rr->data[rr_offset++]; | |
1eedc10f JH |
68 | |
69 | g = string_catn(g, US(rr->data + rr_offset), len); | |
70 | if (g->ptr >= PDKIM_DNS_TXT_MAX_RECLEN) | |
71 | goto bad; | |
72 | ||
1cfe5c1c | 73 | rr_offset += len; |
4263f395 | 74 | } |
dd33c4e6 HSHR |
75 | |
76 | /* check if this looks like a DKIM record */ | |
1eedc10f JH |
77 | if (strncmp(g->s, "v=", 2) != 0 || strncasecmp(g->s, "v=dkim", 6) == 0) |
78 | { | |
79 | store_reset(g->s + g->ptr + 1); | |
80 | return string_from_gstring(g); | |
81 | } | |
82 | ||
83 | if (g) g->ptr = 0; /* overwrite previous record */ | |
80a47a2c | 84 | } |
80a47a2c | 85 | |
1eedc10f JH |
86 | bad: |
87 | if (g) store_reset(g); | |
88 | return NULL; /*XXX better error detail? logging? */ | |
80a47a2c TK |
89 | } |
90 | ||
91 | ||
2592e6c0 JH |
92 | void |
93 | dkim_exim_init(void) | |
94 | { | |
95 | pdkim_init(); | |
96 | } | |
97 | ||
98 | ||
ca9cb170 | 99 | |
1cfe5c1c | 100 | void |
e983e85a | 101 | dkim_exim_verify_init(BOOL dot_stuffing) |
1cfe5c1c | 102 | { |
ca9cb170 JH |
103 | /* There is a store-reset between header & body reception |
104 | so cannot use the main pool. Any allocs done by Exim | |
105 | memory-handling must use the perm pool. */ | |
106 | ||
107 | dkim_verify_oldpool = store_pool; | |
108 | store_pool = POOL_PERM; | |
109 | ||
1cfe5c1c | 110 | /* Free previous context if there is one */ |
80a47a2c | 111 | |
1cfe5c1c JH |
112 | if (dkim_verify_ctx) |
113 | pdkim_free_ctx(dkim_verify_ctx); | |
80a47a2c | 114 | |
1cfe5c1c | 115 | /* Create new context */ |
80a47a2c | 116 | |
e983e85a | 117 | dkim_verify_ctx = pdkim_init_verify(&dkim_exim_query_dns_txt, dot_stuffing); |
3b957582 | 118 | dkim_collect_input = !!dkim_verify_ctx; |
b9df1829 | 119 | dkim_collect_error = NULL; |
ca9cb170 | 120 | |
584e96c6 JH |
121 | /* Start feed up with any cached data */ |
122 | receive_get_cache(); | |
123 | ||
ca9cb170 | 124 | store_pool = dkim_verify_oldpool; |
80a47a2c TK |
125 | } |
126 | ||
127 | ||
1cfe5c1c JH |
128 | void |
129 | dkim_exim_verify_feed(uschar * data, int len) | |
130 | { | |
f7302073 JH |
131 | int rc; |
132 | ||
ca9cb170 | 133 | store_pool = POOL_PERM; |
1cfe5c1c | 134 | if ( dkim_collect_input |
ef698bf6 | 135 | && (rc = pdkim_feed(dkim_verify_ctx, data, len)) != PDKIM_OK) |
f7302073 | 136 | { |
b9df1829 | 137 | dkim_collect_error = pdkim_errstr(rc); |
f7302073 | 138 | log_write(0, LOG_MAIN, |
b9df1829 | 139 | "DKIM: validation error: %.100s", dkim_collect_error); |
1cfe5c1c | 140 | dkim_collect_input = FALSE; |
f7302073 | 141 | } |
ca9cb170 | 142 | store_pool = dkim_verify_oldpool; |
80a47a2c TK |
143 | } |
144 | ||
145 | ||
a79d8834 JH |
146 | /* Log the result for the given signature */ |
147 | static void | |
148 | dkim_exim_verify_log_sig(pdkim_signature * sig) | |
1cfe5c1c | 149 | { |
cc55f420 | 150 | gstring * logmsg; |
a79d8834 JH |
151 | uschar * s; |
152 | ||
cc55f420 JH |
153 | if (!sig) return; |
154 | ||
2c47372f JH |
155 | if ( !dkim_verify_overall |
156 | && dkim_verify_status | |
157 | ? Ustrcmp(dkim_verify_status, US"pass") == 0 | |
158 | : sig->verify_status == PDKIM_VERIFY_PASS | |
159 | ) | |
160 | dkim_verify_overall = string_copy(sig->domain); | |
161 | ||
162 | if (!LOGGING(dkim_verbose)) return; | |
163 | ||
aaaa94ea | 164 | logmsg = string_catn(NULL, US"DKIM: ", 6); |
a79d8834 JH |
165 | if (!(s = sig->domain)) s = US"<UNSET>"; |
166 | logmsg = string_append(logmsg, 2, "d=", s); | |
167 | if (!(s = sig->selector)) s = US"<UNSET>"; | |
168 | logmsg = string_append(logmsg, 2, " s=", s); | |
dd33c4e6 | 169 | logmsg = string_append(logmsg, 7, |
a79d8834 JH |
170 | " c=", sig->canon_headers == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", |
171 | "/", sig->canon_body == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", | |
172 | " a=", dkim_sig_to_a_tag(sig), | |
173 | string_sprintf(" b=" SIZE_T_FMT, | |
174 | (int)sig->sighash.len > -1 ? sig->sighash.len * 8 : 0)); | |
175 | if ((s= sig->identity)) logmsg = string_append(logmsg, 2, " i=", s); | |
176 | if (sig->created > 0) logmsg = string_cat(logmsg, | |
177 | string_sprintf(" t=%lu", sig->created)); | |
178 | if (sig->expires > 0) logmsg = string_cat(logmsg, | |
179 | string_sprintf(" x=%lu", sig->expires)); | |
180 | if (sig->bodylength > -1) logmsg = string_cat(logmsg, | |
181 | string_sprintf(" l=%lu", sig->bodylength)); | |
182 | ||
183 | if ( !dkim_verify_status | |
184 | || ( dkim_verify_status == dkim_exim_expand_query(DKIM_VERIFY_STATUS) | |
185 | && dkim_verify_reason == dkim_exim_expand_query(DKIM_VERIFY_REASON) | |
186 | ) ) | |
1cfe5c1c JH |
187 | switch (sig->verify_status) |
188 | { | |
189 | case PDKIM_VERIFY_NONE: | |
aaaa94ea | 190 | logmsg = string_cat(logmsg, US" [not verified]"); |
80a47a2c | 191 | break; |
1cfe5c1c JH |
192 | |
193 | case PDKIM_VERIFY_INVALID: | |
aaaa94ea | 194 | logmsg = string_cat(logmsg, US" [invalid - "); |
1cfe5c1c JH |
195 | switch (sig->verify_ext_status) |
196 | { | |
197 | case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: | |
acec9514 | 198 | logmsg = string_cat(logmsg, |
aaaa94ea | 199 | US"public key record (currently?) unavailable]"); |
1cfe5c1c JH |
200 | break; |
201 | ||
202 | case PDKIM_VERIFY_INVALID_BUFFER_SIZE: | |
aaaa94ea | 203 | logmsg = string_cat(logmsg, US"overlong public key record]"); |
1cfe5c1c JH |
204 | break; |
205 | ||
df3def24 JH |
206 | case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: |
207 | case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: | |
aaaa94ea | 208 | logmsg = string_cat(logmsg, US"syntax error in public key record]"); |
1cfe5c1c | 209 | break; |
07eeb4df | 210 | |
a79d8834 | 211 | case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: |
aaaa94ea | 212 | logmsg = string_cat(logmsg, US"signature tag missing or invalid]"); |
a79d8834 | 213 | break; |
07eeb4df | 214 | |
a79d8834 | 215 | case PDKIM_VERIFY_INVALID_DKIM_VERSION: |
aaaa94ea | 216 | logmsg = string_cat(logmsg, US"unsupported DKIM version]"); |
a79d8834 | 217 | break; |
1cfe5c1c JH |
218 | |
219 | default: | |
aaaa94ea | 220 | logmsg = string_cat(logmsg, US"unspecified problem]"); |
1cfe5c1c | 221 | } |
80a47a2c | 222 | break; |
1cfe5c1c JH |
223 | |
224 | case PDKIM_VERIFY_FAIL: | |
aaaa94ea | 225 | logmsg = string_cat(logmsg, US" [verification failed - "); |
1cfe5c1c JH |
226 | switch (sig->verify_ext_status) |
227 | { | |
228 | case PDKIM_VERIFY_FAIL_BODY: | |
acec9514 | 229 | logmsg = string_cat(logmsg, |
aaaa94ea | 230 | US"body hash mismatch (body probably modified in transit)]"); |
1cfe5c1c JH |
231 | break; |
232 | ||
233 | case PDKIM_VERIFY_FAIL_MESSAGE: | |
acec9514 | 234 | logmsg = string_cat(logmsg, |
aaaa94ea JH |
235 | US"signature did not verify " |
236 | "(headers probably modified in transit)]"); | |
1cfe5c1c JH |
237 | break; |
238 | ||
239 | default: | |
aaaa94ea | 240 | logmsg = string_cat(logmsg, US"unspecified reason]"); |
1cfe5c1c | 241 | } |
80a47a2c | 242 | break; |
1cfe5c1c JH |
243 | |
244 | case PDKIM_VERIFY_PASS: | |
aaaa94ea | 245 | logmsg = string_cat(logmsg, US" [verification succeeded]"); |
80a47a2c TK |
246 | break; |
247 | } | |
a79d8834 JH |
248 | else |
249 | logmsg = string_append(logmsg, 5, | |
250 | US" [", dkim_verify_status, US" - ", dkim_verify_reason, US"]"); | |
251 | ||
aaaa94ea | 252 | log_write(0, LOG_MAIN, "%s", string_from_gstring(logmsg)); |
a79d8834 JH |
253 | return; |
254 | } | |
255 | ||
80a47a2c | 256 | |
a79d8834 JH |
257 | /* Log a line for each signature */ |
258 | void | |
259 | dkim_exim_verify_log_all(void) | |
260 | { | |
261 | pdkim_signature * sig; | |
262 | for (sig = dkim_signatures; sig; sig = sig->next) dkim_exim_verify_log_sig(sig); | |
263 | } | |
1cfe5c1c | 264 | |
80a47a2c | 265 | |
a79d8834 JH |
266 | void |
267 | dkim_exim_verify_finish(void) | |
268 | { | |
269 | pdkim_signature * sig; | |
270 | int rc; | |
271 | gstring * g = NULL; | |
272 | const uschar * errstr; | |
273 | ||
274 | store_pool = POOL_PERM; | |
275 | ||
276 | /* Delete eventual previous signature chain */ | |
277 | ||
278 | dkim_signers = NULL; | |
279 | dkim_signatures = NULL; | |
280 | ||
281 | if (dkim_collect_error) | |
282 | { | |
283 | log_write(0, LOG_MAIN, | |
284 | "DKIM: Error during validation, disabling signature verification: %.100s", | |
285 | dkim_collect_error); | |
286 | dkim_disable_verify = TRUE; | |
287 | goto out; | |
288 | } | |
289 | ||
290 | dkim_collect_input = FALSE; | |
291 | ||
292 | /* Finish DKIM operation and fetch link to signatures chain */ | |
293 | ||
294 | rc = pdkim_feed_finish(dkim_verify_ctx, &dkim_signatures, &errstr); | |
295 | if (rc != PDKIM_OK) | |
296 | { | |
297 | log_write(0, LOG_MAIN, "DKIM: validation error: %.100s%s%s", pdkim_errstr(rc), | |
298 | errstr ? ": " : "", errstr ? errstr : US""); | |
299 | goto out; | |
300 | } | |
301 | ||
302 | /* Build a colon-separated list of signing domains (and identities, if present) in dkim_signers */ | |
303 | ||
304 | for (sig = dkim_signatures; sig; sig = sig->next) | |
305 | { | |
306 | if (sig->domain) g = string_append_listele(g, ':', sig->domain); | |
307 | if (sig->identity) g = string_append_listele(g, ':', sig->identity); | |
80a47a2c TK |
308 | } |
309 | ||
acec9514 JH |
310 | if (g) dkim_signers = g->s; |
311 | ||
ca9cb170 JH |
312 | out: |
313 | store_pool = dkim_verify_oldpool; | |
80a47a2c TK |
314 | } |
315 | ||
316 | ||
18067c75 JH |
317 | |
318 | /* Args as per dkim_exim_acl_run() below */ | |
319 | static int | |
320 | dkim_acl_call(uschar * id, gstring ** res_ptr, | |
321 | uschar ** user_msgptr, uschar ** log_msgptr) | |
322 | { | |
323 | int rc; | |
324 | DEBUG(D_receive) | |
325 | debug_printf("calling acl_smtp_dkim for dkim_cur_signer='%s'\n", id); | |
326 | ||
327 | rc = acl_check(ACL_WHERE_DKIM, NULL, acl_smtp_dkim, user_msgptr, log_msgptr); | |
328 | dkim_exim_verify_log_sig(dkim_cur_sig); | |
329 | *res_ptr = string_append_listele(*res_ptr, ':', dkim_verify_status); | |
330 | return rc; | |
331 | } | |
332 | ||
333 | ||
334 | ||
335 | /* For the given identity, run the DKIM ACL once for each matching signature. | |
336 | ||
337 | Arguments | |
338 | id Identity to look for in dkim signatures | |
339 | res_ptr ptr to growable string-list of status results, | |
340 | appended to per ACL run | |
341 | user_msgptr where to put a user error (for SMTP response) | |
342 | log_msgptr where to put a logging message (not for SMTP response) | |
343 | ||
344 | Returns: OK access is granted by an ACCEPT verb | |
345 | DISCARD access is granted by a DISCARD verb | |
346 | FAIL access is denied | |
347 | FAIL_DROP access is denied; drop the connection | |
348 | DEFER can't tell at the moment | |
349 | ERROR disaster | |
350 | */ | |
351 | ||
352 | int | |
353 | dkim_exim_acl_run(uschar * id, gstring ** res_ptr, | |
354 | uschar ** user_msgptr, uschar ** log_msgptr) | |
1cfe5c1c JH |
355 | { |
356 | pdkim_signature * sig; | |
357 | uschar * cmp_val; | |
18067c75 | 358 | int rc = -1; |
1cfe5c1c | 359 | |
cc55f420 JH |
360 | dkim_verify_status = US"none"; |
361 | dkim_verify_reason = US""; | |
1cfe5c1c JH |
362 | dkim_cur_signer = id; |
363 | ||
364 | if (dkim_disable_verify || !id || !dkim_verify_ctx) | |
18067c75 | 365 | return OK; |
1cfe5c1c | 366 | |
18067c75 | 367 | /* Find signatures to run ACL on */ |
1cfe5c1c JH |
368 | |
369 | for (sig = dkim_signatures; sig; sig = sig->next) | |
370 | if ( (cmp_val = Ustrchr(id, '@') != NULL ? US sig->identity : US sig->domain) | |
371 | && strcmpic(cmp_val, id) == 0 | |
372 | ) | |
373 | { | |
1cfe5c1c | 374 | /* The "dkim_domain" and "dkim_selector" expansion variables have |
18067c75 JH |
375 | related globals, since they are used in the signing code too. |
376 | Instead of inventing separate names for verification, we set | |
377 | them here. This is easy since a domain and selector is guaranteed | |
378 | to be in a signature. The other dkim_* expansion items are | |
379 | dynamically fetched from dkim_cur_sig at expansion time (see | |
380 | function below). */ | |
1cfe5c1c | 381 | |
18067c75 | 382 | dkim_cur_sig = sig; |
1cfe5c1c JH |
383 | dkim_signing_domain = US sig->domain; |
384 | dkim_signing_selector = US sig->selector; | |
dcd03763 | 385 | dkim_key_length = sig->sighash.len * 8; |
a79d8834 JH |
386 | |
387 | /* These two return static strings, so we can compare the addr | |
388 | later to see if the ACL overwrote them. Check that when logging */ | |
389 | ||
390 | dkim_verify_status = dkim_exim_expand_query(DKIM_VERIFY_STATUS); | |
391 | dkim_verify_reason = dkim_exim_expand_query(DKIM_VERIFY_REASON); | |
dd33c4e6 | 392 | |
18067c75 JH |
393 | if ((rc = dkim_acl_call(id, res_ptr, user_msgptr, log_msgptr)) != OK) |
394 | return rc; | |
80a47a2c | 395 | } |
18067c75 JH |
396 | |
397 | if (rc != -1) | |
398 | return rc; | |
399 | ||
400 | /* No matching sig found. Call ACL once anyway. */ | |
401 | ||
402 | dkim_cur_sig = NULL; | |
403 | return dkim_acl_call(id, res_ptr, user_msgptr, log_msgptr); | |
80a47a2c TK |
404 | } |
405 | ||
406 | ||
1cfe5c1c JH |
407 | static uschar * |
408 | dkim_exim_expand_defaults(int what) | |
409 | { | |
410 | switch (what) | |
411 | { | |
412 | case DKIM_ALGO: return US""; | |
413 | case DKIM_BODYLENGTH: return US"9999999999999"; | |
414 | case DKIM_CANON_BODY: return US""; | |
415 | case DKIM_CANON_HEADERS: return US""; | |
416 | case DKIM_COPIEDHEADERS: return US""; | |
417 | case DKIM_CREATED: return US"0"; | |
418 | case DKIM_EXPIRES: return US"9999999999999"; | |
419 | case DKIM_HEADERNAMES: return US""; | |
420 | case DKIM_IDENTITY: return US""; | |
421 | case DKIM_KEY_GRANULARITY: return US"*"; | |
422 | case DKIM_KEY_SRVTYPE: return US"*"; | |
423 | case DKIM_KEY_NOTES: return US""; | |
424 | case DKIM_KEY_TESTING: return US"0"; | |
425 | case DKIM_NOSUBDOMAINS: return US"0"; | |
426 | case DKIM_VERIFY_STATUS: return US"none"; | |
427 | case DKIM_VERIFY_REASON: return US""; | |
428 | default: return US""; | |
429 | } | |
430 | } | |
80a47a2c | 431 | |
80a47a2c | 432 | |
1cfe5c1c JH |
433 | uschar * |
434 | dkim_exim_expand_query(int what) | |
435 | { | |
436 | if (!dkim_verify_ctx || dkim_disable_verify || !dkim_cur_sig) | |
437 | return dkim_exim_expand_defaults(what); | |
438 | ||
439 | switch (what) | |
440 | { | |
441 | case DKIM_ALGO: | |
d73e45df | 442 | return dkim_sig_to_a_tag(dkim_cur_sig); |
1cfe5c1c JH |
443 | |
444 | case DKIM_BODYLENGTH: | |
445 | return dkim_cur_sig->bodylength >= 0 | |
bb07bcd3 | 446 | ? string_sprintf("%ld", dkim_cur_sig->bodylength) |
1cfe5c1c JH |
447 | : dkim_exim_expand_defaults(what); |
448 | ||
449 | case DKIM_CANON_BODY: | |
450 | switch (dkim_cur_sig->canon_body) | |
451 | { | |
452 | case PDKIM_CANON_RELAXED: return US"relaxed"; | |
453 | case PDKIM_CANON_SIMPLE: | |
454 | default: return US"simple"; | |
80a47a2c | 455 | } |
1cfe5c1c JH |
456 | |
457 | case DKIM_CANON_HEADERS: | |
a79d8834 JH |
458 | switch (dkim_cur_sig->canon_headers) |
459 | { | |
460 | case PDKIM_CANON_RELAXED: return US"relaxed"; | |
461 | case PDKIM_CANON_SIMPLE: | |
462 | default: return US"simple"; | |
463 | } | |
1cfe5c1c JH |
464 | |
465 | case DKIM_COPIEDHEADERS: | |
466 | return dkim_cur_sig->copiedheaders | |
467 | ? US dkim_cur_sig->copiedheaders : dkim_exim_expand_defaults(what); | |
468 | ||
469 | case DKIM_CREATED: | |
470 | return dkim_cur_sig->created > 0 | |
bb07bcd3 | 471 | ? string_sprintf("%lu", dkim_cur_sig->created) |
1cfe5c1c JH |
472 | : dkim_exim_expand_defaults(what); |
473 | ||
474 | case DKIM_EXPIRES: | |
475 | return dkim_cur_sig->expires > 0 | |
bb07bcd3 | 476 | ? string_sprintf("%lu", dkim_cur_sig->expires) |
1cfe5c1c JH |
477 | : dkim_exim_expand_defaults(what); |
478 | ||
479 | case DKIM_HEADERNAMES: | |
480 | return dkim_cur_sig->headernames | |
2592e6c0 | 481 | ? dkim_cur_sig->headernames : dkim_exim_expand_defaults(what); |
1cfe5c1c JH |
482 | |
483 | case DKIM_IDENTITY: | |
484 | return dkim_cur_sig->identity | |
485 | ? US dkim_cur_sig->identity : dkim_exim_expand_defaults(what); | |
486 | ||
487 | case DKIM_KEY_GRANULARITY: | |
488 | return dkim_cur_sig->pubkey | |
489 | ? dkim_cur_sig->pubkey->granularity | |
490 | ? US dkim_cur_sig->pubkey->granularity | |
491 | : dkim_exim_expand_defaults(what) | |
492 | : dkim_exim_expand_defaults(what); | |
493 | ||
494 | case DKIM_KEY_SRVTYPE: | |
495 | return dkim_cur_sig->pubkey | |
496 | ? dkim_cur_sig->pubkey->srvtype | |
497 | ? US dkim_cur_sig->pubkey->srvtype | |
498 | : dkim_exim_expand_defaults(what) | |
499 | : dkim_exim_expand_defaults(what); | |
500 | ||
501 | case DKIM_KEY_NOTES: | |
502 | return dkim_cur_sig->pubkey | |
503 | ? dkim_cur_sig->pubkey->notes | |
504 | ? US dkim_cur_sig->pubkey->notes | |
505 | : dkim_exim_expand_defaults(what) | |
506 | : dkim_exim_expand_defaults(what); | |
507 | ||
508 | case DKIM_KEY_TESTING: | |
509 | return dkim_cur_sig->pubkey | |
510 | ? dkim_cur_sig->pubkey->testing | |
511 | ? US"1" | |
512 | : dkim_exim_expand_defaults(what) | |
513 | : dkim_exim_expand_defaults(what); | |
514 | ||
515 | case DKIM_NOSUBDOMAINS: | |
516 | return dkim_cur_sig->pubkey | |
517 | ? dkim_cur_sig->pubkey->no_subdomaining | |
518 | ? US"1" | |
519 | : dkim_exim_expand_defaults(what) | |
520 | : dkim_exim_expand_defaults(what); | |
521 | ||
522 | case DKIM_VERIFY_STATUS: | |
523 | switch (dkim_cur_sig->verify_status) | |
524 | { | |
525 | case PDKIM_VERIFY_INVALID: return US"invalid"; | |
526 | case PDKIM_VERIFY_FAIL: return US"fail"; | |
527 | case PDKIM_VERIFY_PASS: return US"pass"; | |
528 | case PDKIM_VERIFY_NONE: | |
529 | default: return US"none"; | |
80a47a2c | 530 | } |
80a47a2c | 531 | |
1cfe5c1c JH |
532 | case DKIM_VERIFY_REASON: |
533 | switch (dkim_cur_sig->verify_ext_status) | |
534 | { | |
535 | case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: | |
536 | return US"pubkey_unavailable"; | |
df3def24 JH |
537 | case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD:return US"pubkey_dns_syntax"; |
538 | case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: return US"pubkey_der_syntax"; | |
1cfe5c1c JH |
539 | case PDKIM_VERIFY_FAIL_BODY: return US"bodyhash_mismatch"; |
540 | case PDKIM_VERIFY_FAIL_MESSAGE: return US"signature_incorrect"; | |
541 | } | |
80a47a2c | 542 | |
1cfe5c1c JH |
543 | default: |
544 | return US""; | |
80a47a2c TK |
545 | } |
546 | } | |
547 | ||
548 | ||
0b8f4f1a | 549 | /* Generate signatures for the given file. |
42055a33 | 550 | If a prefix is given, prepend it to the file for the calculations. |
0b8f4f1a JH |
551 | |
552 | Return: | |
553 | NULL: error; error string written | |
554 | string: signature header(s), or a zero-length string (not an error) | |
42055a33 JH |
555 | */ |
556 | ||
acec9514 | 557 | gstring * |
42055a33 JH |
558 | dkim_exim_sign(int fd, off_t off, uschar * prefix, |
559 | struct ob_dkim * dkim, const uschar ** errstr) | |
55414b25 | 560 | { |
e983e85a | 561 | const uschar * dkim_domain; |
1cfe5c1c | 562 | int sep = 0; |
acec9514 | 563 | gstring * seen_doms = NULL; |
9e70917d JH |
564 | pdkim_ctx ctx; |
565 | pdkim_signature * sig; | |
acec9514 | 566 | gstring * sigbuf; |
1cfe5c1c JH |
567 | int pdkim_rc; |
568 | int sread; | |
ef698bf6 | 569 | uschar buf[4096]; |
1cfe5c1c JH |
570 | int save_errno = 0; |
571 | int old_pool = store_pool; | |
7c6ec81b | 572 | uschar * errwhen; |
1cfe5c1c JH |
573 | |
574 | store_pool = POOL_MAIN; | |
575 | ||
9e70917d JH |
576 | pdkim_init_context(&ctx, dkim->dot_stuffed, &dkim_exim_query_dns_txt); |
577 | ||
e983e85a | 578 | if (!(dkim_domain = expand_cstring(dkim->dkim_domain))) |
1cfe5c1c | 579 | /* expansion error, do not send message. */ |
7c6ec81b | 580 | { errwhen = US"dkim_domain"; goto expand_bad; } |
1cfe5c1c JH |
581 | |
582 | /* Set $dkim_domain expansion variable to each unique domain in list. */ | |
583 | ||
42055a33 | 584 | while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, NULL, 0))) |
1cfe5c1c | 585 | { |
9e70917d JH |
586 | const uschar * dkim_sel; |
587 | int sel_sep = 0; | |
588 | ||
42055a33 | 589 | if (dkim_signing_domain[0] == '\0') |
1cfe5c1c JH |
590 | continue; |
591 | ||
592 | /* Only sign once for each domain, no matter how often it | |
593 | appears in the expanded list. */ | |
594 | ||
9e70917d JH |
595 | if (match_isinlist(dkim_signing_domain, CUSS &seen_doms, |
596 | 0, NULL, NULL, MCL_STRING, TRUE, NULL) == OK) | |
597 | continue; | |
1cfe5c1c | 598 | |
acec9514 | 599 | seen_doms = string_append_listele(seen_doms, ':', dkim_signing_domain); |
1cfe5c1c | 600 | |
9e70917d JH |
601 | /* Set $dkim_selector expansion variable to each selector in list, |
602 | for this domain. */ | |
1cfe5c1c | 603 | |
9e70917d | 604 | if (!(dkim_sel = expand_string(dkim->dkim_selector))) |
e983e85a | 605 | if (!(dkim_signing_selector = expand_string(dkim->dkim_selector))) |
7c6ec81b | 606 | { errwhen = US"dkim_selector"; goto expand_bad; } |
1cfe5c1c | 607 | |
9e70917d JH |
608 | while ((dkim_signing_selector = string_nextinlist(&dkim_sel, &sel_sep, |
609 | NULL, 0))) | |
1cfe5c1c | 610 | { |
9e70917d JH |
611 | uschar * dkim_canon_expanded; |
612 | int pdkim_canon; | |
613 | uschar * dkim_sign_headers_expanded = NULL; | |
614 | uschar * dkim_private_key_expanded; | |
615 | uschar * dkim_hash_expanded; | |
7c6ec81b | 616 | uschar * dkim_identity_expanded = NULL; |
80a47a2c | 617 | |
9e70917d | 618 | /* Get canonicalization to use */ |
1cfe5c1c | 619 | |
9e70917d JH |
620 | dkim_canon_expanded = dkim->dkim_canon |
621 | ? expand_string(dkim->dkim_canon) : US"relaxed"; | |
7c6ec81b JH |
622 | if (!dkim_canon_expanded) /* expansion error, do not send message. */ |
623 | { errwhen = US"dkim_canon"; goto expand_bad; } | |
1cfe5c1c | 624 | |
9e70917d JH |
625 | if (Ustrcmp(dkim_canon_expanded, "relaxed") == 0) |
626 | pdkim_canon = PDKIM_CANON_RELAXED; | |
627 | else if (Ustrcmp(dkim_canon_expanded, "simple") == 0) | |
628 | pdkim_canon = PDKIM_CANON_SIMPLE; | |
629 | else | |
630 | { | |
631 | log_write(0, LOG_MAIN, | |
632 | "DKIM: unknown canonicalization method '%s', defaulting to 'relaxed'.\n", | |
633 | dkim_canon_expanded); | |
634 | pdkim_canon = PDKIM_CANON_RELAXED; | |
635 | } | |
1cfe5c1c | 636 | |
7c6ec81b JH |
637 | if ( dkim->dkim_sign_headers |
638 | && !(dkim_sign_headers_expanded = expand_string(dkim->dkim_sign_headers))) | |
639 | { errwhen = US"dkim_sign_header"; goto expand_bad; } | |
640 | /* else pass NULL, which means default header list */ | |
1cfe5c1c | 641 | |
9e70917d | 642 | /* Get private key to use. */ |
e983e85a | 643 | |
9e70917d | 644 | if (!(dkim_private_key_expanded = expand_string(dkim->dkim_private_key))) |
7c6ec81b | 645 | { errwhen = US"dkim_private_key"; goto expand_bad; } |
80a47a2c | 646 | |
9e70917d JH |
647 | if ( Ustrlen(dkim_private_key_expanded) == 0 |
648 | || Ustrcmp(dkim_private_key_expanded, "0") == 0 | |
649 | || Ustrcmp(dkim_private_key_expanded, "false") == 0 | |
650 | ) | |
651 | continue; /* don't sign, but no error */ | |
652 | ||
653 | if (dkim_private_key_expanded[0] == '/') | |
1cfe5c1c | 654 | { |
9e70917d JH |
655 | int privkey_fd, off = 0, len; |
656 | ||
657 | /* Looks like a filename, load the private key. */ | |
658 | ||
659 | memset(big_buffer, 0, big_buffer_size); | |
660 | ||
661 | if ((privkey_fd = open(CS dkim_private_key_expanded, O_RDONLY)) < 0) | |
59d98039 | 662 | { |
9e70917d JH |
663 | log_write(0, LOG_MAIN | LOG_PANIC, "unable to open " |
664 | "private key file for reading: %s", | |
59d98039 JH |
665 | dkim_private_key_expanded); |
666 | goto bad; | |
667 | } | |
9e70917d JH |
668 | |
669 | do | |
670 | { | |
671 | if ((len = read(privkey_fd, big_buffer + off, big_buffer_size - 2 - off)) < 0) | |
672 | { | |
673 | (void) close(privkey_fd); | |
674 | log_write(0, LOG_MAIN|LOG_PANIC, "unable to read private key file: %s", | |
675 | dkim_private_key_expanded); | |
676 | goto bad; | |
677 | } | |
678 | off += len; | |
679 | } | |
680 | while (len > 0); | |
681 | ||
682 | (void) close(privkey_fd); | |
683 | big_buffer[off] = '\0'; | |
684 | dkim_private_key_expanded = big_buffer; | |
1ac6b2e7 | 685 | } |
80a47a2c | 686 | |
9e70917d | 687 | if (!(dkim_hash_expanded = expand_string(dkim->dkim_hash))) |
7c6ec81b JH |
688 | { errwhen = US"dkim_hash"; goto expand_bad; } |
689 | ||
690 | if (dkim->dkim_identity) | |
691 | if (!(dkim_identity_expanded = expand_string(dkim->dkim_identity))) | |
692 | { errwhen = US"dkim_identity"; goto expand_bad; } | |
693 | else if (!*dkim_identity_expanded) | |
694 | dkim_identity_expanded = NULL; | |
1cfe5c1c | 695 | |
9e70917d JH |
696 | /*XXX so we currently nail signing to RSA + this hash. |
697 | Need to extract algo from privkey and check for disallowed combos. */ | |
d73e45df | 698 | |
9e70917d JH |
699 | if (!(sig = pdkim_init_sign(&ctx, dkim_signing_domain, |
700 | dkim_signing_selector, | |
701 | dkim_private_key_expanded, | |
702 | dkim_hash_expanded, | |
703 | errstr | |
704 | ))) | |
705 | goto bad; | |
706 | dkim_private_key_expanded[0] = '\0'; | |
707 | ||
708 | pdkim_set_optional(sig, | |
709 | CS dkim_sign_headers_expanded, | |
27fd1318 | 710 | CS dkim_identity_expanded, |
9e70917d JH |
711 | pdkim_canon, |
712 | pdkim_canon, -1, 0, 0); | |
713 | ||
714 | if (!ctx.sig) /* link sig to context chain */ | |
715 | ctx.sig = sig; | |
716 | else | |
717 | { | |
718 | pdkim_signature * n = ctx.sig; | |
719 | while (n->next) n = n->next; | |
720 | n->next = sig; | |
721 | } | |
80a47a2c | 722 | } |
9e70917d | 723 | } |
0b8f4f1a JH |
724 | if (!ctx.sig) |
725 | { | |
726 | DEBUG(D_transport) debug_printf("DKIM: no viable signatures to use\n"); | |
727 | sigbuf = string_get(1); /* return a zero-len string */ | |
728 | goto CLEANUP; | |
729 | } | |
80a47a2c | 730 | |
0b8f4f1a JH |
731 | if (prefix && (pdkim_feed(&ctx, prefix, Ustrlen(prefix))) != PDKIM_OK) |
732 | goto pk_bad; | |
80a47a2c | 733 | |
9e70917d JH |
734 | if (lseek(fd, off, SEEK_SET) < 0) |
735 | sread = -1; | |
736 | else | |
737 | while ((sread = read(fd, &buf, sizeof(buf))) > 0) | |
738 | if ((pdkim_rc = pdkim_feed(&ctx, buf, sread)) != PDKIM_OK) | |
739 | goto pk_bad; | |
80a47a2c | 740 | |
9e70917d JH |
741 | /* Handle failed read above. */ |
742 | if (sread == -1) | |
743 | { | |
744 | debug_printf("DKIM: Error reading -K file.\n"); | |
745 | save_errno = errno; | |
746 | goto bad; | |
80a47a2c | 747 | } |
a8e1eeba | 748 | |
9e70917d JH |
749 | /* Build string of headers, one per signature */ |
750 | ||
751 | if ((pdkim_rc = pdkim_feed_finish(&ctx, &sig, errstr)) != PDKIM_OK) | |
752 | goto pk_bad; | |
753 | ||
acec9514 JH |
754 | for (sigbuf = NULL; sig; sig = sig->next) |
755 | sigbuf = string_append(sigbuf, 2, US sig->signature_header, US"\r\n"); | |
9e70917d | 756 | |
1cfe5c1c | 757 | CLEANUP: |
0b8f4f1a | 758 | (void) string_from_gstring(sigbuf); |
f7302073 JH |
759 | store_pool = old_pool; |
760 | errno = save_errno; | |
9e70917d | 761 | return sigbuf; |
f7302073 JH |
762 | |
763 | pk_bad: | |
764 | log_write(0, LOG_MAIN|LOG_PANIC, | |
765 | "DKIM: signing failed: %.100s", pdkim_errstr(pdkim_rc)); | |
766 | bad: | |
9e70917d | 767 | sigbuf = NULL; |
f7302073 | 768 | goto CLEANUP; |
7c6ec81b JH |
769 | |
770 | expand_bad: | |
771 | log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand %s: %s", | |
772 | errwhen, expand_string_message); | |
773 | goto bad; | |
93f2d376 | 774 | } |
80a47a2c | 775 | |
970424a5 JH |
776 | # endif /*!MACRO_PREDEF*/ |
777 | #endif /*!DISABLE_DKIM*/ |