Commit | Line | Data |
---|---|---|
80a47a2c TK |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
80fea873 | 5 | /* Copyright (c) University of Cambridge, 1995 - 2016 */ |
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 | ||
15 | #include "pdkim/pdkim.h" | |
16 | ||
ca9cb170 | 17 | int dkim_verify_oldpool; |
1cfe5c1c | 18 | pdkim_ctx *dkim_verify_ctx = NULL; |
80a47a2c | 19 | pdkim_signature *dkim_signatures = NULL; |
1cfe5c1c | 20 | pdkim_signature *dkim_cur_sig = NULL; |
80a47a2c | 21 | |
1cfe5c1c JH |
22 | static int |
23 | dkim_exim_query_dns_txt(char *name, char *answer) | |
24 | { | |
25 | dns_answer dnsa; | |
26 | dns_scan dnss; | |
27 | dns_record *rr; | |
80a47a2c | 28 | |
1cfe5c1c JH |
29 | lookup_dnssec_authenticated = NULL; |
30 | if (dns_lookup(&dnsa, US name, T_TXT, NULL) != DNS_SUCCEED) | |
f7302073 | 31 | return PDKIM_FAIL; /*XXX better error detail? logging? */ |
80a47a2c | 32 | |
1cfe5c1c | 33 | /* Search for TXT record */ |
80a47a2c | 34 | |
1cfe5c1c JH |
35 | for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS); |
36 | rr; | |
37 | rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) | |
38 | if (rr->type == T_TXT) | |
39 | { | |
80a47a2c TK |
40 | int rr_offset = 0; |
41 | int answer_offset = 0; | |
1cfe5c1c JH |
42 | |
43 | /* Copy record content to the answer buffer */ | |
44 | ||
45 | while (rr_offset < rr->size) | |
46 | { | |
47 | uschar len = rr->data[rr_offset++]; | |
48 | snprintf(answer + answer_offset, | |
49 | PDKIM_DNS_TXT_MAX_RECLEN - answer_offset, | |
50 | "%.*s", (int)len, (char *) (rr->data + rr_offset)); | |
51 | rr_offset += len; | |
52 | answer_offset += len; | |
53 | if (answer_offset >= PDKIM_DNS_TXT_MAX_RECLEN) | |
f7302073 | 54 | return PDKIM_FAIL; /*XXX better error detail? logging? */ |
4263f395 | 55 | } |
1cfe5c1c | 56 | return PDKIM_OK; |
80a47a2c | 57 | } |
80a47a2c | 58 | |
f7302073 | 59 | return PDKIM_FAIL; /*XXX better error detail? logging? */ |
80a47a2c TK |
60 | } |
61 | ||
62 | ||
2592e6c0 JH |
63 | void |
64 | dkim_exim_init(void) | |
65 | { | |
66 | pdkim_init(); | |
67 | } | |
68 | ||
69 | ||
ca9cb170 | 70 | |
1cfe5c1c JH |
71 | void |
72 | dkim_exim_verify_init(void) | |
73 | { | |
ca9cb170 JH |
74 | /* There is a store-reset between header & body reception |
75 | so cannot use the main pool. Any allocs done by Exim | |
76 | memory-handling must use the perm pool. */ | |
77 | ||
78 | dkim_verify_oldpool = store_pool; | |
79 | store_pool = POOL_PERM; | |
80 | ||
1cfe5c1c | 81 | /* Free previous context if there is one */ |
80a47a2c | 82 | |
1cfe5c1c JH |
83 | if (dkim_verify_ctx) |
84 | pdkim_free_ctx(dkim_verify_ctx); | |
80a47a2c | 85 | |
1cfe5c1c | 86 | /* Create new context */ |
80a47a2c | 87 | |
0d04a285 | 88 | dkim_verify_ctx = pdkim_init_verify(&dkim_exim_query_dns_txt); |
3b957582 | 89 | dkim_collect_input = !!dkim_verify_ctx; |
ca9cb170 JH |
90 | |
91 | store_pool = dkim_verify_oldpool; | |
80a47a2c TK |
92 | } |
93 | ||
94 | ||
1cfe5c1c JH |
95 | void |
96 | dkim_exim_verify_feed(uschar * data, int len) | |
97 | { | |
f7302073 JH |
98 | int rc; |
99 | ||
ca9cb170 | 100 | store_pool = POOL_PERM; |
1cfe5c1c | 101 | if ( dkim_collect_input |
f7302073 JH |
102 | && (rc = pdkim_feed(dkim_verify_ctx, (char *)data, len)) != PDKIM_OK) |
103 | { | |
104 | log_write(0, LOG_MAIN, | |
105 | "DKIM: validation error: %.100s", pdkim_errstr(rc)); | |
1cfe5c1c | 106 | dkim_collect_input = FALSE; |
f7302073 | 107 | } |
ca9cb170 | 108 | store_pool = dkim_verify_oldpool; |
80a47a2c TK |
109 | } |
110 | ||
111 | ||
1cfe5c1c JH |
112 | void |
113 | dkim_exim_verify_finish(void) | |
114 | { | |
115 | pdkim_signature *sig = NULL; | |
116 | int dkim_signers_size = 0; | |
117 | int dkim_signers_ptr = 0; | |
118 | dkim_signers = NULL; | |
f7302073 | 119 | int rc; |
1cfe5c1c | 120 | |
ca9cb170 JH |
121 | store_pool = POOL_PERM; |
122 | ||
1cfe5c1c JH |
123 | /* Delete eventual previous signature chain */ |
124 | ||
125 | dkim_signatures = NULL; | |
126 | ||
127 | /* If we have arrived here with dkim_collect_input == FALSE, it | |
128 | means there was a processing error somewhere along the way. | |
129 | Log the incident and disable futher verification. */ | |
130 | ||
131 | if (!dkim_collect_input) | |
132 | { | |
133 | log_write(0, LOG_MAIN, | |
134 | "DKIM: Error while running this message through validation," | |
135 | " disabling signature verification."); | |
136 | dkim_disable_verify = TRUE; | |
ca9cb170 | 137 | goto out; |
1cfe5c1c | 138 | } |
80a47a2c | 139 | |
1cfe5c1c | 140 | dkim_collect_input = FALSE; |
80a47a2c | 141 | |
1cfe5c1c | 142 | /* Finish DKIM operation and fetch link to signatures chain */ |
80a47a2c | 143 | |
f7302073 JH |
144 | if ((rc = pdkim_feed_finish(dkim_verify_ctx, &dkim_signatures)) != PDKIM_OK) |
145 | { | |
146 | log_write(0, LOG_MAIN, | |
147 | "DKIM: validation error: %.100s", pdkim_errstr(rc)); | |
ca9cb170 | 148 | goto out; |
f7302073 | 149 | } |
1cfe5c1c JH |
150 | |
151 | for (sig = dkim_signatures; sig; sig = sig->next) | |
152 | { | |
153 | int size = 0; | |
154 | int ptr = 0; | |
155 | ||
156 | /* Log a line for each signature */ | |
157 | ||
158 | uschar *logmsg = string_append(NULL, &size, &ptr, 5, | |
abe1010c | 159 | string_sprintf("d=%s s=%s c=%s/%s a=%s b=%d ", |
1cfe5c1c JH |
160 | sig->domain, |
161 | sig->selector, | |
07eeb4df | 162 | sig->canon_headers == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", |
163 | sig->canon_body == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", | |
164 | sig->algo == PDKIM_ALGO_RSA_SHA256 | |
165 | ? "rsa-sha256" | |
166 | : sig->algo == PDKIM_ALGO_RSA_SHA1 ? "rsa-sha1" : "err", | |
167 | (int)sig->sigdata.len > -1 ? sig->sigdata.len * 8 : 0 | |
abe1010c | 168 | ), |
1cfe5c1c JH |
169 | |
170 | sig->identity ? string_sprintf("i=%s ", sig->identity) : US"", | |
171 | sig->created > 0 ? string_sprintf("t=%lu ", sig->created) : US"", | |
172 | sig->expires > 0 ? string_sprintf("x=%lu ", sig->expires) : US"", | |
173 | sig->bodylength > -1 ? string_sprintf("l=%lu ", sig->bodylength) : US"" | |
174 | ); | |
175 | ||
176 | switch (sig->verify_status) | |
177 | { | |
178 | case PDKIM_VERIFY_NONE: | |
179 | logmsg = string_append(logmsg, &size, &ptr, 1, "[not verified]"); | |
80a47a2c | 180 | break; |
1cfe5c1c JH |
181 | |
182 | case PDKIM_VERIFY_INVALID: | |
183 | logmsg = string_append(logmsg, &size, &ptr, 1, "[invalid - "); | |
184 | switch (sig->verify_ext_status) | |
185 | { | |
186 | case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: | |
187 | logmsg = string_append(logmsg, &size, &ptr, 1, | |
188 | "public key record (currently?) unavailable]"); | |
189 | break; | |
190 | ||
191 | case PDKIM_VERIFY_INVALID_BUFFER_SIZE: | |
192 | logmsg = string_append(logmsg, &size, &ptr, 1, | |
193 | "overlong public key record]"); | |
194 | break; | |
195 | ||
df3def24 JH |
196 | case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: |
197 | case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: | |
1cfe5c1c JH |
198 | logmsg = string_append(logmsg, &size, &ptr, 1, |
199 | "syntax error in public key record]"); | |
200 | break; | |
07eeb4df | 201 | |
202 | case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: | |
203 | logmsg = string_append(logmsg, &size, &ptr, 1, | |
204 | "signature tag missing or invalid]"); | |
205 | break; | |
206 | ||
207 | case PDKIM_VERIFY_INVALID_DKIM_VERSION: | |
208 | logmsg = string_append(logmsg, &size, &ptr, 1, | |
209 | "unsupported DKIM version]"); | |
210 | break; | |
1cfe5c1c JH |
211 | |
212 | default: | |
213 | logmsg = string_append(logmsg, &size, &ptr, 1, | |
214 | "unspecified problem]"); | |
215 | } | |
80a47a2c | 216 | break; |
1cfe5c1c JH |
217 | |
218 | case PDKIM_VERIFY_FAIL: | |
219 | logmsg = | |
220 | string_append(logmsg, &size, &ptr, 1, "[verification failed - "); | |
221 | switch (sig->verify_ext_status) | |
222 | { | |
223 | case PDKIM_VERIFY_FAIL_BODY: | |
224 | logmsg = string_append(logmsg, &size, &ptr, 1, | |
225 | "body hash mismatch (body probably modified in transit)]"); | |
226 | break; | |
227 | ||
228 | case PDKIM_VERIFY_FAIL_MESSAGE: | |
229 | logmsg = string_append(logmsg, &size, &ptr, 1, | |
230 | "signature did not verify (headers probably modified in transit)]"); | |
231 | break; | |
232 | ||
233 | default: | |
234 | logmsg = string_append(logmsg, &size, &ptr, 1, "unspecified reason]"); | |
235 | } | |
80a47a2c | 236 | break; |
1cfe5c1c JH |
237 | |
238 | case PDKIM_VERIFY_PASS: | |
239 | logmsg = | |
240 | string_append(logmsg, &size, &ptr, 1, "[verification succeeded]"); | |
80a47a2c TK |
241 | break; |
242 | } | |
243 | ||
1cfe5c1c JH |
244 | logmsg[ptr] = '\0'; |
245 | log_write(0, LOG_MAIN, "DKIM: %s", logmsg); | |
80a47a2c | 246 | |
1cfe5c1c JH |
247 | /* Build a colon-separated list of signing domains (and identities, if present) in dkim_signers */ |
248 | ||
249 | dkim_signers = string_append(dkim_signers, | |
250 | &dkim_signers_size, | |
251 | &dkim_signers_ptr, 2, sig->domain, ":"); | |
252 | ||
253 | if (sig->identity) | |
9e5d6b55 | 254 | dkim_signers = string_append(dkim_signers, |
1cfe5c1c JH |
255 | &dkim_signers_size, |
256 | &dkim_signers_ptr, 2, sig->identity, ":"); | |
80a47a2c | 257 | |
1cfe5c1c | 258 | /* Process next signature */ |
80a47a2c TK |
259 | } |
260 | ||
1cfe5c1c JH |
261 | /* NULL-terminate and chop the last colon from the domain list */ |
262 | ||
263 | if (dkim_signers) | |
264 | { | |
265 | dkim_signers[dkim_signers_ptr] = '\0'; | |
266 | if (Ustrlen(dkim_signers) > 0) | |
267 | dkim_signers[Ustrlen(dkim_signers) - 1] = '\0'; | |
0d2b278d | 268 | } |
ca9cb170 JH |
269 | |
270 | out: | |
271 | store_pool = dkim_verify_oldpool; | |
80a47a2c TK |
272 | } |
273 | ||
274 | ||
1cfe5c1c JH |
275 | void |
276 | dkim_exim_acl_setup(uschar * id) | |
277 | { | |
278 | pdkim_signature * sig; | |
279 | uschar * cmp_val; | |
280 | ||
1cfe5c1c JH |
281 | dkim_cur_sig = NULL; |
282 | dkim_cur_signer = id; | |
283 | ||
284 | if (dkim_disable_verify || !id || !dkim_verify_ctx) | |
285 | return; | |
286 | ||
287 | /* Find signature to run ACL on */ | |
288 | ||
289 | for (sig = dkim_signatures; sig; sig = sig->next) | |
290 | if ( (cmp_val = Ustrchr(id, '@') != NULL ? US sig->identity : US sig->domain) | |
291 | && strcmpic(cmp_val, id) == 0 | |
292 | ) | |
293 | { | |
294 | dkim_cur_sig = sig; | |
295 | ||
296 | /* The "dkim_domain" and "dkim_selector" expansion variables have | |
297 | related globals, since they are used in the signing code too. | |
298 | Instead of inventing separate names for verification, we set | |
299 | them here. This is easy since a domain and selector is guaranteed | |
300 | to be in a signature. The other dkim_* expansion items are | |
301 | dynamically fetched from dkim_cur_sig at expansion time (see | |
302 | function below). */ | |
303 | ||
304 | dkim_signing_domain = US sig->domain; | |
305 | dkim_signing_selector = US sig->selector; | |
2592e6c0 | 306 | dkim_key_length = sig->sigdata.len * 8; |
1cfe5c1c | 307 | return; |
80a47a2c | 308 | } |
80a47a2c TK |
309 | } |
310 | ||
311 | ||
1cfe5c1c JH |
312 | static uschar * |
313 | dkim_exim_expand_defaults(int what) | |
314 | { | |
315 | switch (what) | |
316 | { | |
317 | case DKIM_ALGO: return US""; | |
318 | case DKIM_BODYLENGTH: return US"9999999999999"; | |
319 | case DKIM_CANON_BODY: return US""; | |
320 | case DKIM_CANON_HEADERS: return US""; | |
321 | case DKIM_COPIEDHEADERS: return US""; | |
322 | case DKIM_CREATED: return US"0"; | |
323 | case DKIM_EXPIRES: return US"9999999999999"; | |
324 | case DKIM_HEADERNAMES: return US""; | |
325 | case DKIM_IDENTITY: return US""; | |
326 | case DKIM_KEY_GRANULARITY: return US"*"; | |
327 | case DKIM_KEY_SRVTYPE: return US"*"; | |
328 | case DKIM_KEY_NOTES: return US""; | |
329 | case DKIM_KEY_TESTING: return US"0"; | |
330 | case DKIM_NOSUBDOMAINS: return US"0"; | |
331 | case DKIM_VERIFY_STATUS: return US"none"; | |
332 | case DKIM_VERIFY_REASON: return US""; | |
333 | default: return US""; | |
334 | } | |
335 | } | |
80a47a2c | 336 | |
80a47a2c | 337 | |
1cfe5c1c JH |
338 | uschar * |
339 | dkim_exim_expand_query(int what) | |
340 | { | |
341 | if (!dkim_verify_ctx || dkim_disable_verify || !dkim_cur_sig) | |
342 | return dkim_exim_expand_defaults(what); | |
343 | ||
344 | switch (what) | |
345 | { | |
346 | case DKIM_ALGO: | |
347 | switch (dkim_cur_sig->algo) | |
348 | { | |
349 | case PDKIM_ALGO_RSA_SHA1: return US"rsa-sha1"; | |
350 | case PDKIM_ALGO_RSA_SHA256: | |
351 | default: return US"rsa-sha256"; | |
da5dfc3a | 352 | } |
1cfe5c1c JH |
353 | |
354 | case DKIM_BODYLENGTH: | |
355 | return dkim_cur_sig->bodylength >= 0 | |
356 | ? string_sprintf(OFF_T_FMT, (LONGLONG_T) dkim_cur_sig->bodylength) | |
357 | : dkim_exim_expand_defaults(what); | |
358 | ||
359 | case DKIM_CANON_BODY: | |
360 | switch (dkim_cur_sig->canon_body) | |
361 | { | |
362 | case PDKIM_CANON_RELAXED: return US"relaxed"; | |
363 | case PDKIM_CANON_SIMPLE: | |
364 | default: return US"simple"; | |
80a47a2c | 365 | } |
1cfe5c1c JH |
366 | |
367 | case DKIM_CANON_HEADERS: | |
368 | switch (dkim_cur_sig->canon_headers) | |
369 | { | |
370 | case PDKIM_CANON_RELAXED: return US"relaxed"; | |
371 | case PDKIM_CANON_SIMPLE: | |
372 | default: return US"simple"; | |
373 | } | |
374 | ||
375 | case DKIM_COPIEDHEADERS: | |
376 | return dkim_cur_sig->copiedheaders | |
377 | ? US dkim_cur_sig->copiedheaders : dkim_exim_expand_defaults(what); | |
378 | ||
379 | case DKIM_CREATED: | |
380 | return dkim_cur_sig->created > 0 | |
381 | ? string_sprintf("%llu", dkim_cur_sig->created) | |
382 | : dkim_exim_expand_defaults(what); | |
383 | ||
384 | case DKIM_EXPIRES: | |
385 | return dkim_cur_sig->expires > 0 | |
386 | ? string_sprintf("%llu", dkim_cur_sig->expires) | |
387 | : dkim_exim_expand_defaults(what); | |
388 | ||
389 | case DKIM_HEADERNAMES: | |
390 | return dkim_cur_sig->headernames | |
2592e6c0 | 391 | ? dkim_cur_sig->headernames : dkim_exim_expand_defaults(what); |
1cfe5c1c JH |
392 | |
393 | case DKIM_IDENTITY: | |
394 | return dkim_cur_sig->identity | |
395 | ? US dkim_cur_sig->identity : dkim_exim_expand_defaults(what); | |
396 | ||
397 | case DKIM_KEY_GRANULARITY: | |
398 | return dkim_cur_sig->pubkey | |
399 | ? dkim_cur_sig->pubkey->granularity | |
400 | ? US dkim_cur_sig->pubkey->granularity | |
401 | : dkim_exim_expand_defaults(what) | |
402 | : dkim_exim_expand_defaults(what); | |
403 | ||
404 | case DKIM_KEY_SRVTYPE: | |
405 | return dkim_cur_sig->pubkey | |
406 | ? dkim_cur_sig->pubkey->srvtype | |
407 | ? US dkim_cur_sig->pubkey->srvtype | |
408 | : dkim_exim_expand_defaults(what) | |
409 | : dkim_exim_expand_defaults(what); | |
410 | ||
411 | case DKIM_KEY_NOTES: | |
412 | return dkim_cur_sig->pubkey | |
413 | ? dkim_cur_sig->pubkey->notes | |
414 | ? US dkim_cur_sig->pubkey->notes | |
415 | : dkim_exim_expand_defaults(what) | |
416 | : dkim_exim_expand_defaults(what); | |
417 | ||
418 | case DKIM_KEY_TESTING: | |
419 | return dkim_cur_sig->pubkey | |
420 | ? dkim_cur_sig->pubkey->testing | |
421 | ? US"1" | |
422 | : dkim_exim_expand_defaults(what) | |
423 | : dkim_exim_expand_defaults(what); | |
424 | ||
425 | case DKIM_NOSUBDOMAINS: | |
426 | return dkim_cur_sig->pubkey | |
427 | ? dkim_cur_sig->pubkey->no_subdomaining | |
428 | ? US"1" | |
429 | : dkim_exim_expand_defaults(what) | |
430 | : dkim_exim_expand_defaults(what); | |
431 | ||
432 | case DKIM_VERIFY_STATUS: | |
433 | switch (dkim_cur_sig->verify_status) | |
434 | { | |
435 | case PDKIM_VERIFY_INVALID: return US"invalid"; | |
436 | case PDKIM_VERIFY_FAIL: return US"fail"; | |
437 | case PDKIM_VERIFY_PASS: return US"pass"; | |
438 | case PDKIM_VERIFY_NONE: | |
439 | default: return US"none"; | |
80a47a2c | 440 | } |
80a47a2c | 441 | |
1cfe5c1c JH |
442 | case DKIM_VERIFY_REASON: |
443 | switch (dkim_cur_sig->verify_ext_status) | |
444 | { | |
445 | case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: | |
446 | return US"pubkey_unavailable"; | |
df3def24 JH |
447 | case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD:return US"pubkey_dns_syntax"; |
448 | case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: return US"pubkey_der_syntax"; | |
1cfe5c1c JH |
449 | case PDKIM_VERIFY_FAIL_BODY: return US"bodyhash_mismatch"; |
450 | case PDKIM_VERIFY_FAIL_MESSAGE: return US"signature_incorrect"; | |
451 | } | |
80a47a2c | 452 | |
1cfe5c1c JH |
453 | default: |
454 | return US""; | |
80a47a2c TK |
455 | } |
456 | } | |
457 | ||
458 | ||
55414b25 | 459 | uschar * |
1cfe5c1c JH |
460 | dkim_exim_sign(int dkim_fd, uschar * dkim_private_key, |
461 | const uschar * dkim_domain, uschar * dkim_selector, | |
462 | uschar * dkim_canon, uschar * dkim_sign_headers) | |
55414b25 | 463 | { |
1cfe5c1c JH |
464 | int sep = 0; |
465 | uschar *seen_items = NULL; | |
466 | int seen_items_size = 0; | |
467 | int seen_items_offset = 0; | |
468 | uschar itembuf[256]; | |
469 | uschar *dkim_canon_expanded; | |
470 | uschar *dkim_sign_headers_expanded; | |
471 | uschar *dkim_private_key_expanded; | |
472 | pdkim_ctx *ctx = NULL; | |
473 | uschar *rc = NULL; | |
474 | uschar *sigbuf = NULL; | |
475 | int sigsize = 0; | |
476 | int sigptr = 0; | |
477 | pdkim_signature *signature; | |
478 | int pdkim_canon; | |
479 | int pdkim_rc; | |
480 | int sread; | |
481 | char buf[4096]; | |
482 | int save_errno = 0; | |
483 | int old_pool = store_pool; | |
484 | ||
485 | store_pool = POOL_MAIN; | |
486 | ||
487 | if (!(dkim_domain = expand_cstring(dkim_domain))) | |
488 | { | |
489 | /* expansion error, do not send message. */ | |
490 | log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand " | |
491 | "dkim_domain: %s", expand_string_message); | |
f7302073 | 492 | goto bad; |
1cfe5c1c JH |
493 | } |
494 | ||
495 | /* Set $dkim_domain expansion variable to each unique domain in list. */ | |
496 | ||
497 | while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, | |
498 | itembuf, sizeof(itembuf)))) | |
499 | { | |
500 | if (!dkim_signing_domain || dkim_signing_domain[0] == '\0') | |
501 | continue; | |
502 | ||
503 | /* Only sign once for each domain, no matter how often it | |
504 | appears in the expanded list. */ | |
505 | ||
506 | if (seen_items) | |
507 | { | |
508 | const uschar *seen_items_list = seen_items; | |
509 | if (match_isinlist(dkim_signing_domain, | |
510 | &seen_items_list, 0, NULL, NULL, MCL_STRING, TRUE, | |
511 | NULL) == OK) | |
512 | continue; | |
513 | ||
514 | seen_items = | |
515 | string_append(seen_items, &seen_items_size, &seen_items_offset, 1, ":"); | |
516 | } | |
517 | ||
518 | seen_items = | |
519 | string_append(seen_items, &seen_items_size, &seen_items_offset, 1, | |
520 | dkim_signing_domain); | |
521 | seen_items[seen_items_offset] = '\0'; | |
522 | ||
523 | /* Set up $dkim_selector expansion variable. */ | |
524 | ||
525 | if (!(dkim_signing_selector = expand_string(dkim_selector))) | |
526 | { | |
527 | log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand " | |
528 | "dkim_selector: %s", expand_string_message); | |
f7302073 | 529 | goto bad; |
1cfe5c1c JH |
530 | } |
531 | ||
532 | /* Get canonicalization to use */ | |
533 | ||
534 | dkim_canon_expanded = dkim_canon ? expand_string(dkim_canon) : US"relaxed"; | |
535 | if (!dkim_canon_expanded) | |
536 | { | |
80a47a2c | 537 | /* expansion error, do not send message. */ |
1cfe5c1c JH |
538 | log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand " |
539 | "dkim_canon: %s", expand_string_message); | |
f7302073 | 540 | goto bad; |
1cfe5c1c | 541 | } |
80a47a2c | 542 | |
1cfe5c1c JH |
543 | if (Ustrcmp(dkim_canon_expanded, "relaxed") == 0) |
544 | pdkim_canon = PDKIM_CANON_RELAXED; | |
545 | else if (Ustrcmp(dkim_canon_expanded, "simple") == 0) | |
546 | pdkim_canon = PDKIM_CANON_SIMPLE; | |
547 | else | |
548 | { | |
549 | log_write(0, LOG_MAIN, | |
550 | "DKIM: unknown canonicalization method '%s', defaulting to 'relaxed'.\n", | |
551 | dkim_canon_expanded); | |
552 | pdkim_canon = PDKIM_CANON_RELAXED; | |
a8e1eeba | 553 | } |
1cfe5c1c JH |
554 | |
555 | dkim_sign_headers_expanded = NULL; | |
556 | if (dkim_sign_headers) | |
557 | if (!(dkim_sign_headers_expanded = expand_string(dkim_sign_headers))) | |
558 | { | |
559 | log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand " | |
560 | "dkim_sign_headers: %s", expand_string_message); | |
f7302073 | 561 | goto bad; |
1cfe5c1c JH |
562 | } |
563 | /* else pass NULL, which means default header list */ | |
564 | ||
565 | /* Get private key to use. */ | |
566 | ||
567 | if (!(dkim_private_key_expanded = expand_string(dkim_private_key))) | |
568 | { | |
569 | log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand " | |
570 | "dkim_private_key: %s", expand_string_message); | |
f7302073 | 571 | goto bad; |
a8e1eeba | 572 | } |
80a47a2c | 573 | |
1cfe5c1c JH |
574 | if ( Ustrlen(dkim_private_key_expanded) == 0 |
575 | || Ustrcmp(dkim_private_key_expanded, "0") == 0 | |
576 | || Ustrcmp(dkim_private_key_expanded, "false") == 0 | |
577 | ) | |
578 | continue; /* don't sign, but no error */ | |
579 | ||
580 | if (dkim_private_key_expanded[0] == '/') | |
581 | { | |
582 | int privkey_fd = 0; | |
583 | ||
584 | /* Looks like a filename, load the private key. */ | |
585 | ||
586 | memset(big_buffer, 0, big_buffer_size); | |
587 | privkey_fd = open(CS dkim_private_key_expanded, O_RDONLY); | |
588 | if (privkey_fd < 0) | |
589 | { | |
590 | log_write(0, LOG_MAIN | LOG_PANIC, "unable to open " | |
591 | "private key file for reading: %s", | |
592 | dkim_private_key_expanded); | |
f7302073 | 593 | goto bad; |
db4d0902 | 594 | } |
80a47a2c | 595 | |
1cfe5c1c JH |
596 | if (read(privkey_fd, big_buffer, big_buffer_size - 2) < 0) |
597 | { | |
598 | log_write(0, LOG_MAIN|LOG_PANIC, "unable to read private key file: %s", | |
599 | dkim_private_key_expanded); | |
f7302073 | 600 | goto bad; |
1ac6b2e7 | 601 | } |
80a47a2c | 602 | |
1cfe5c1c JH |
603 | (void) close(privkey_fd); |
604 | dkim_private_key_expanded = big_buffer; | |
a8e1eeba | 605 | } |
1cfe5c1c | 606 | |
f7302073 JH |
607 | ctx = pdkim_init_sign( CS dkim_signing_domain, |
608 | CS dkim_signing_selector, | |
609 | CS dkim_private_key_expanded, | |
f444c2c7 | 610 | PDKIM_ALGO_RSA_SHA256); |
1cfe5c1c JH |
611 | pdkim_set_optional(ctx, |
612 | (char *) dkim_sign_headers_expanded, | |
613 | NULL, | |
614 | pdkim_canon, | |
f444c2c7 | 615 | pdkim_canon, -1, 0, 0); |
1cfe5c1c JH |
616 | |
617 | lseek(dkim_fd, 0, SEEK_SET); | |
618 | ||
619 | while ((sread = read(dkim_fd, &buf, 4096)) > 0) | |
f7302073 JH |
620 | if ((pdkim_rc = pdkim_feed(ctx, buf, sread)) != PDKIM_OK) |
621 | goto pk_bad; | |
1cfe5c1c JH |
622 | |
623 | /* Handle failed read above. */ | |
624 | if (sread == -1) | |
625 | { | |
626 | debug_printf("DKIM: Error reading -K file.\n"); | |
627 | save_errno = errno; | |
f7302073 | 628 | goto bad; |
80a47a2c | 629 | } |
80a47a2c | 630 | |
1cfe5c1c | 631 | if ((pdkim_rc = pdkim_feed_finish(ctx, &signature)) != PDKIM_OK) |
f7302073 | 632 | goto pk_bad; |
80a47a2c | 633 | |
1cfe5c1c JH |
634 | sigbuf = string_append(sigbuf, &sigsize, &sigptr, 2, |
635 | US signature->signature_header, US"\r\n"); | |
80a47a2c | 636 | |
1cfe5c1c JH |
637 | pdkim_free_ctx(ctx); |
638 | ctx = NULL; | |
80a47a2c | 639 | } |
a8e1eeba | 640 | |
1cfe5c1c JH |
641 | if (sigbuf) |
642 | { | |
643 | sigbuf[sigptr] = '\0'; | |
644 | rc = sigbuf; | |
645 | } | |
646 | else | |
647 | rc = US""; | |
648 | ||
649 | CLEANUP: | |
f7302073 JH |
650 | if (ctx) |
651 | pdkim_free_ctx(ctx); | |
652 | store_pool = old_pool; | |
653 | errno = save_errno; | |
654 | return rc; | |
655 | ||
656 | pk_bad: | |
657 | log_write(0, LOG_MAIN|LOG_PANIC, | |
658 | "DKIM: signing failed: %.100s", pdkim_errstr(pdkim_rc)); | |
659 | bad: | |
660 | rc = NULL; | |
661 | goto CLEANUP; | |
93f2d376 | 662 | } |
80a47a2c TK |
663 | |
664 | #endif |