Commit | Line | Data |
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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 | ||
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; |
b9df1829 | 21 | static const uschar * dkim_collect_error = NULL; |
80a47a2c | 22 | |
1cfe5c1c JH |
23 | static int |
24 | dkim_exim_query_dns_txt(char *name, char *answer) | |
25 | { | |
26 | dns_answer dnsa; | |
27 | dns_scan dnss; | |
28 | dns_record *rr; | |
80a47a2c | 29 | |
1cfe5c1c JH |
30 | lookup_dnssec_authenticated = NULL; |
31 | if (dns_lookup(&dnsa, US name, T_TXT, NULL) != DNS_SUCCEED) | |
f7302073 | 32 | return PDKIM_FAIL; /*XXX better error detail? logging? */ |
80a47a2c | 33 | |
1cfe5c1c | 34 | /* Search for TXT record */ |
80a47a2c | 35 | |
1cfe5c1c JH |
36 | for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS); |
37 | rr; | |
38 | rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) | |
39 | if (rr->type == T_TXT) | |
40 | { | |
80a47a2c TK |
41 | int rr_offset = 0; |
42 | int answer_offset = 0; | |
1cfe5c1c JH |
43 | |
44 | /* Copy record content to the answer buffer */ | |
45 | ||
46 | while (rr_offset < rr->size) | |
47 | { | |
48 | uschar len = rr->data[rr_offset++]; | |
49 | snprintf(answer + answer_offset, | |
50 | PDKIM_DNS_TXT_MAX_RECLEN - answer_offset, | |
51 | "%.*s", (int)len, (char *) (rr->data + rr_offset)); | |
52 | rr_offset += len; | |
53 | answer_offset += len; | |
54 | if (answer_offset >= PDKIM_DNS_TXT_MAX_RECLEN) | |
f7302073 | 55 | return PDKIM_FAIL; /*XXX better error detail? logging? */ |
4263f395 | 56 | } |
1cfe5c1c | 57 | return PDKIM_OK; |
80a47a2c | 58 | } |
80a47a2c | 59 | |
f7302073 | 60 | return PDKIM_FAIL; /*XXX better error detail? logging? */ |
80a47a2c TK |
61 | } |
62 | ||
63 | ||
2592e6c0 JH |
64 | void |
65 | dkim_exim_init(void) | |
66 | { | |
67 | pdkim_init(); | |
68 | } | |
69 | ||
70 | ||
ca9cb170 | 71 | |
1cfe5c1c | 72 | void |
e983e85a | 73 | dkim_exim_verify_init(BOOL dot_stuffing) |
1cfe5c1c | 74 | { |
ca9cb170 JH |
75 | /* There is a store-reset between header & body reception |
76 | so cannot use the main pool. Any allocs done by Exim | |
77 | memory-handling must use the perm pool. */ | |
78 | ||
79 | dkim_verify_oldpool = store_pool; | |
80 | store_pool = POOL_PERM; | |
81 | ||
1cfe5c1c | 82 | /* Free previous context if there is one */ |
80a47a2c | 83 | |
1cfe5c1c JH |
84 | if (dkim_verify_ctx) |
85 | pdkim_free_ctx(dkim_verify_ctx); | |
80a47a2c | 86 | |
1cfe5c1c | 87 | /* Create new context */ |
80a47a2c | 88 | |
e983e85a | 89 | dkim_verify_ctx = pdkim_init_verify(&dkim_exim_query_dns_txt, dot_stuffing); |
3b957582 | 90 | dkim_collect_input = !!dkim_verify_ctx; |
b9df1829 | 91 | dkim_collect_error = NULL; |
ca9cb170 | 92 | |
584e96c6 JH |
93 | /* Start feed up with any cached data */ |
94 | receive_get_cache(); | |
95 | ||
ca9cb170 | 96 | store_pool = dkim_verify_oldpool; |
80a47a2c TK |
97 | } |
98 | ||
99 | ||
1cfe5c1c JH |
100 | void |
101 | dkim_exim_verify_feed(uschar * data, int len) | |
102 | { | |
f7302073 JH |
103 | int rc; |
104 | ||
ca9cb170 | 105 | store_pool = POOL_PERM; |
1cfe5c1c | 106 | if ( dkim_collect_input |
e983e85a | 107 | && (rc = pdkim_feed(dkim_verify_ctx, CS data, len)) != PDKIM_OK) |
f7302073 | 108 | { |
b9df1829 | 109 | dkim_collect_error = pdkim_errstr(rc); |
f7302073 | 110 | log_write(0, LOG_MAIN, |
b9df1829 | 111 | "DKIM: validation error: %.100s", dkim_collect_error); |
1cfe5c1c | 112 | dkim_collect_input = FALSE; |
f7302073 | 113 | } |
ca9cb170 | 114 | store_pool = dkim_verify_oldpool; |
80a47a2c TK |
115 | } |
116 | ||
117 | ||
1cfe5c1c JH |
118 | void |
119 | dkim_exim_verify_finish(void) | |
120 | { | |
41468ba1 | 121 | pdkim_signature * sig = NULL; |
b9df1829 JH |
122 | int dkim_signers_size = 0, dkim_signers_ptr = 0, rc; |
123 | const uschar * errstr; | |
1cfe5c1c | 124 | |
ca9cb170 JH |
125 | store_pool = POOL_PERM; |
126 | ||
1cfe5c1c JH |
127 | /* Delete eventual previous signature chain */ |
128 | ||
41468ba1 | 129 | dkim_signers = NULL; |
1cfe5c1c JH |
130 | dkim_signatures = NULL; |
131 | ||
bd8fbe36 | 132 | if (dkim_collect_error) |
1cfe5c1c JH |
133 | { |
134 | log_write(0, LOG_MAIN, | |
b9df1829 JH |
135 | "DKIM: Error during validation, disabling signature verification: %.100s", |
136 | dkim_collect_error); | |
1cfe5c1c | 137 | dkim_disable_verify = TRUE; |
ca9cb170 | 138 | goto out; |
1cfe5c1c | 139 | } |
80a47a2c | 140 | |
1cfe5c1c | 141 | dkim_collect_input = FALSE; |
80a47a2c | 142 | |
1cfe5c1c | 143 | /* Finish DKIM operation and fetch link to signatures chain */ |
80a47a2c | 144 | |
b9df1829 JH |
145 | rc = pdkim_feed_finish(dkim_verify_ctx, &dkim_signatures, &errstr); |
146 | if (rc != PDKIM_OK) | |
f7302073 | 147 | { |
b9df1829 JH |
148 | log_write(0, LOG_MAIN, "DKIM: validation error: %.100s%s%s", pdkim_errstr(rc), |
149 | errstr ? ": " : "", errstr ? errstr : US""); | |
ca9cb170 | 150 | goto out; |
f7302073 | 151 | } |
1cfe5c1c JH |
152 | |
153 | for (sig = dkim_signatures; sig; sig = sig->next) | |
154 | { | |
41468ba1 JH |
155 | int size = 0, ptr = 0; |
156 | uschar * logmsg = NULL, * s; | |
1cfe5c1c JH |
157 | |
158 | /* Log a line for each signature */ | |
159 | ||
41468ba1 JH |
160 | if (!(s = sig->domain)) s = US"<UNSET>"; |
161 | logmsg = string_append(logmsg, &size, &ptr, 2, "d=", s); | |
162 | if (!(s = sig->selector)) s = US"<UNSET>"; | |
163 | logmsg = string_append(logmsg, &size, &ptr, 2, " s=", s); | |
164 | logmsg = string_append(logmsg, &size, &ptr, 7, | |
165 | " c=", sig->canon_headers == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", | |
166 | "/", sig->canon_body == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", | |
167 | " a=", sig->algo == PDKIM_ALGO_RSA_SHA256 | |
168 | ? "rsa-sha256" | |
169 | : sig->algo == PDKIM_ALGO_RSA_SHA1 ? "rsa-sha1" : "err", | |
170 | string_sprintf(" b=%d", | |
171 | (int)sig->sighash.len > -1 ? sig->sighash.len * 8 : 0)); | |
31323b30 HSHR |
172 | if ((s= sig->identity)) logmsg = string_append(logmsg, &size, &ptr, 2, " i=", s); |
173 | if (sig->created > 0) logmsg = string_append(logmsg, &size, &ptr, 1, | |
41468ba1 | 174 | string_sprintf(" t=%lu", sig->created)); |
31323b30 | 175 | if (sig->expires > 0) logmsg = string_append(logmsg, &size, &ptr, 1, |
41468ba1 | 176 | string_sprintf(" x=%lu", sig->expires)); |
31323b30 | 177 | if (sig->bodylength > -1) logmsg = string_append(logmsg, &size, &ptr, 1, |
41468ba1 | 178 | string_sprintf(" l=%lu", sig->bodylength)); |
1cfe5c1c JH |
179 | |
180 | switch (sig->verify_status) | |
181 | { | |
182 | case PDKIM_VERIFY_NONE: | |
41468ba1 | 183 | logmsg = string_append(logmsg, &size, &ptr, 1, " [not verified]"); |
80a47a2c | 184 | break; |
1cfe5c1c JH |
185 | |
186 | case PDKIM_VERIFY_INVALID: | |
41468ba1 | 187 | logmsg = string_append(logmsg, &size, &ptr, 1, " [invalid - "); |
1cfe5c1c JH |
188 | switch (sig->verify_ext_status) |
189 | { | |
190 | case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: | |
191 | logmsg = string_append(logmsg, &size, &ptr, 1, | |
192 | "public key record (currently?) unavailable]"); | |
193 | break; | |
194 | ||
195 | case PDKIM_VERIFY_INVALID_BUFFER_SIZE: | |
196 | logmsg = string_append(logmsg, &size, &ptr, 1, | |
197 | "overlong public key record]"); | |
198 | break; | |
199 | ||
df3def24 JH |
200 | case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: |
201 | case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: | |
1cfe5c1c JH |
202 | logmsg = string_append(logmsg, &size, &ptr, 1, |
203 | "syntax error in public key record]"); | |
204 | break; | |
07eeb4df | 205 | |
206 | case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: | |
207 | logmsg = string_append(logmsg, &size, &ptr, 1, | |
208 | "signature tag missing or invalid]"); | |
209 | break; | |
210 | ||
211 | case PDKIM_VERIFY_INVALID_DKIM_VERSION: | |
212 | logmsg = string_append(logmsg, &size, &ptr, 1, | |
213 | "unsupported DKIM version]"); | |
214 | break; | |
1cfe5c1c JH |
215 | |
216 | default: | |
217 | logmsg = string_append(logmsg, &size, &ptr, 1, | |
218 | "unspecified problem]"); | |
219 | } | |
80a47a2c | 220 | break; |
1cfe5c1c JH |
221 | |
222 | case PDKIM_VERIFY_FAIL: | |
223 | logmsg = | |
41468ba1 | 224 | string_append(logmsg, &size, &ptr, 1, " [verification failed - "); |
1cfe5c1c JH |
225 | switch (sig->verify_ext_status) |
226 | { | |
227 | case PDKIM_VERIFY_FAIL_BODY: | |
228 | logmsg = string_append(logmsg, &size, &ptr, 1, | |
229 | "body hash mismatch (body probably modified in transit)]"); | |
230 | break; | |
231 | ||
232 | case PDKIM_VERIFY_FAIL_MESSAGE: | |
233 | logmsg = string_append(logmsg, &size, &ptr, 1, | |
234 | "signature did not verify (headers probably modified in transit)]"); | |
235 | break; | |
236 | ||
237 | default: | |
238 | logmsg = string_append(logmsg, &size, &ptr, 1, "unspecified reason]"); | |
239 | } | |
80a47a2c | 240 | break; |
1cfe5c1c JH |
241 | |
242 | case PDKIM_VERIFY_PASS: | |
243 | logmsg = | |
41468ba1 | 244 | string_append(logmsg, &size, &ptr, 1, " [verification succeeded]"); |
80a47a2c TK |
245 | break; |
246 | } | |
247 | ||
1cfe5c1c JH |
248 | logmsg[ptr] = '\0'; |
249 | log_write(0, LOG_MAIN, "DKIM: %s", logmsg); | |
80a47a2c | 250 | |
1cfe5c1c JH |
251 | /* Build a colon-separated list of signing domains (and identities, if present) in dkim_signers */ |
252 | ||
41468ba1 JH |
253 | if (sig->domain) |
254 | dkim_signers = string_append_listele(dkim_signers, ':', sig->domain); | |
1cfe5c1c JH |
255 | |
256 | if (sig->identity) | |
41468ba1 | 257 | dkim_signers = string_append_listele(dkim_signers, ':', sig->identity); |
80a47a2c | 258 | |
1cfe5c1c | 259 | /* Process next signature */ |
80a47a2c TK |
260 | } |
261 | ||
ca9cb170 JH |
262 | out: |
263 | store_pool = dkim_verify_oldpool; | |
80a47a2c TK |
264 | } |
265 | ||
266 | ||
1cfe5c1c JH |
267 | void |
268 | dkim_exim_acl_setup(uschar * id) | |
269 | { | |
270 | pdkim_signature * sig; | |
271 | uschar * cmp_val; | |
272 | ||
1cfe5c1c JH |
273 | dkim_cur_sig = NULL; |
274 | dkim_cur_signer = id; | |
275 | ||
276 | if (dkim_disable_verify || !id || !dkim_verify_ctx) | |
277 | return; | |
278 | ||
279 | /* Find signature to run ACL on */ | |
280 | ||
281 | for (sig = dkim_signatures; sig; sig = sig->next) | |
282 | if ( (cmp_val = Ustrchr(id, '@') != NULL ? US sig->identity : US sig->domain) | |
283 | && strcmpic(cmp_val, id) == 0 | |
284 | ) | |
285 | { | |
286 | dkim_cur_sig = sig; | |
287 | ||
288 | /* The "dkim_domain" and "dkim_selector" expansion variables have | |
289 | related globals, since they are used in the signing code too. | |
290 | Instead of inventing separate names for verification, we set | |
291 | them here. This is easy since a domain and selector is guaranteed | |
292 | to be in a signature. The other dkim_* expansion items are | |
293 | dynamically fetched from dkim_cur_sig at expansion time (see | |
294 | function below). */ | |
295 | ||
296 | dkim_signing_domain = US sig->domain; | |
297 | dkim_signing_selector = US sig->selector; | |
dcd03763 | 298 | dkim_key_length = sig->sighash.len * 8; |
1cfe5c1c | 299 | return; |
80a47a2c | 300 | } |
80a47a2c TK |
301 | } |
302 | ||
303 | ||
1cfe5c1c JH |
304 | static uschar * |
305 | dkim_exim_expand_defaults(int what) | |
306 | { | |
307 | switch (what) | |
308 | { | |
309 | case DKIM_ALGO: return US""; | |
310 | case DKIM_BODYLENGTH: return US"9999999999999"; | |
311 | case DKIM_CANON_BODY: return US""; | |
312 | case DKIM_CANON_HEADERS: return US""; | |
313 | case DKIM_COPIEDHEADERS: return US""; | |
314 | case DKIM_CREATED: return US"0"; | |
315 | case DKIM_EXPIRES: return US"9999999999999"; | |
316 | case DKIM_HEADERNAMES: return US""; | |
317 | case DKIM_IDENTITY: return US""; | |
318 | case DKIM_KEY_GRANULARITY: return US"*"; | |
319 | case DKIM_KEY_SRVTYPE: return US"*"; | |
320 | case DKIM_KEY_NOTES: return US""; | |
321 | case DKIM_KEY_TESTING: return US"0"; | |
322 | case DKIM_NOSUBDOMAINS: return US"0"; | |
323 | case DKIM_VERIFY_STATUS: return US"none"; | |
324 | case DKIM_VERIFY_REASON: return US""; | |
325 | default: return US""; | |
326 | } | |
327 | } | |
80a47a2c | 328 | |
80a47a2c | 329 | |
1cfe5c1c JH |
330 | uschar * |
331 | dkim_exim_expand_query(int what) | |
332 | { | |
333 | if (!dkim_verify_ctx || dkim_disable_verify || !dkim_cur_sig) | |
334 | return dkim_exim_expand_defaults(what); | |
335 | ||
336 | switch (what) | |
337 | { | |
338 | case DKIM_ALGO: | |
339 | switch (dkim_cur_sig->algo) | |
340 | { | |
341 | case PDKIM_ALGO_RSA_SHA1: return US"rsa-sha1"; | |
342 | case PDKIM_ALGO_RSA_SHA256: | |
343 | default: return US"rsa-sha256"; | |
da5dfc3a | 344 | } |
1cfe5c1c JH |
345 | |
346 | case DKIM_BODYLENGTH: | |
347 | return dkim_cur_sig->bodylength >= 0 | |
348 | ? string_sprintf(OFF_T_FMT, (LONGLONG_T) dkim_cur_sig->bodylength) | |
349 | : dkim_exim_expand_defaults(what); | |
350 | ||
351 | case DKIM_CANON_BODY: | |
352 | switch (dkim_cur_sig->canon_body) | |
353 | { | |
354 | case PDKIM_CANON_RELAXED: return US"relaxed"; | |
355 | case PDKIM_CANON_SIMPLE: | |
356 | default: return US"simple"; | |
80a47a2c | 357 | } |
1cfe5c1c JH |
358 | |
359 | case DKIM_CANON_HEADERS: | |
360 | switch (dkim_cur_sig->canon_headers) | |
361 | { | |
362 | case PDKIM_CANON_RELAXED: return US"relaxed"; | |
363 | case PDKIM_CANON_SIMPLE: | |
364 | default: return US"simple"; | |
365 | } | |
366 | ||
367 | case DKIM_COPIEDHEADERS: | |
368 | return dkim_cur_sig->copiedheaders | |
369 | ? US dkim_cur_sig->copiedheaders : dkim_exim_expand_defaults(what); | |
370 | ||
371 | case DKIM_CREATED: | |
372 | return dkim_cur_sig->created > 0 | |
373 | ? string_sprintf("%llu", dkim_cur_sig->created) | |
374 | : dkim_exim_expand_defaults(what); | |
375 | ||
376 | case DKIM_EXPIRES: | |
377 | return dkim_cur_sig->expires > 0 | |
378 | ? string_sprintf("%llu", dkim_cur_sig->expires) | |
379 | : dkim_exim_expand_defaults(what); | |
380 | ||
381 | case DKIM_HEADERNAMES: | |
382 | return dkim_cur_sig->headernames | |
2592e6c0 | 383 | ? dkim_cur_sig->headernames : dkim_exim_expand_defaults(what); |
1cfe5c1c JH |
384 | |
385 | case DKIM_IDENTITY: | |
386 | return dkim_cur_sig->identity | |
387 | ? US dkim_cur_sig->identity : dkim_exim_expand_defaults(what); | |
388 | ||
389 | case DKIM_KEY_GRANULARITY: | |
390 | return dkim_cur_sig->pubkey | |
391 | ? dkim_cur_sig->pubkey->granularity | |
392 | ? US dkim_cur_sig->pubkey->granularity | |
393 | : dkim_exim_expand_defaults(what) | |
394 | : dkim_exim_expand_defaults(what); | |
395 | ||
396 | case DKIM_KEY_SRVTYPE: | |
397 | return dkim_cur_sig->pubkey | |
398 | ? dkim_cur_sig->pubkey->srvtype | |
399 | ? US dkim_cur_sig->pubkey->srvtype | |
400 | : dkim_exim_expand_defaults(what) | |
401 | : dkim_exim_expand_defaults(what); | |
402 | ||
403 | case DKIM_KEY_NOTES: | |
404 | return dkim_cur_sig->pubkey | |
405 | ? dkim_cur_sig->pubkey->notes | |
406 | ? US dkim_cur_sig->pubkey->notes | |
407 | : dkim_exim_expand_defaults(what) | |
408 | : dkim_exim_expand_defaults(what); | |
409 | ||
410 | case DKIM_KEY_TESTING: | |
411 | return dkim_cur_sig->pubkey | |
412 | ? dkim_cur_sig->pubkey->testing | |
413 | ? US"1" | |
414 | : dkim_exim_expand_defaults(what) | |
415 | : dkim_exim_expand_defaults(what); | |
416 | ||
417 | case DKIM_NOSUBDOMAINS: | |
418 | return dkim_cur_sig->pubkey | |
419 | ? dkim_cur_sig->pubkey->no_subdomaining | |
420 | ? US"1" | |
421 | : dkim_exim_expand_defaults(what) | |
422 | : dkim_exim_expand_defaults(what); | |
423 | ||
424 | case DKIM_VERIFY_STATUS: | |
425 | switch (dkim_cur_sig->verify_status) | |
426 | { | |
427 | case PDKIM_VERIFY_INVALID: return US"invalid"; | |
428 | case PDKIM_VERIFY_FAIL: return US"fail"; | |
429 | case PDKIM_VERIFY_PASS: return US"pass"; | |
430 | case PDKIM_VERIFY_NONE: | |
431 | default: return US"none"; | |
80a47a2c | 432 | } |
80a47a2c | 433 | |
1cfe5c1c JH |
434 | case DKIM_VERIFY_REASON: |
435 | switch (dkim_cur_sig->verify_ext_status) | |
436 | { | |
437 | case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: | |
438 | return US"pubkey_unavailable"; | |
df3def24 JH |
439 | case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD:return US"pubkey_dns_syntax"; |
440 | case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: return US"pubkey_der_syntax"; | |
1cfe5c1c JH |
441 | case PDKIM_VERIFY_FAIL_BODY: return US"bodyhash_mismatch"; |
442 | case PDKIM_VERIFY_FAIL_MESSAGE: return US"signature_incorrect"; | |
443 | } | |
80a47a2c | 444 | |
1cfe5c1c JH |
445 | default: |
446 | return US""; | |
80a47a2c TK |
447 | } |
448 | } | |
449 | ||
450 | ||
42055a33 JH |
451 | /* Generate signatures for the given file, returning a string. |
452 | If a prefix is given, prepend it to the file for the calculations. | |
453 | */ | |
454 | ||
55414b25 | 455 | uschar * |
42055a33 JH |
456 | dkim_exim_sign(int fd, off_t off, uschar * prefix, |
457 | struct ob_dkim * dkim, const uschar ** errstr) | |
55414b25 | 458 | { |
e983e85a | 459 | const uschar * dkim_domain; |
1cfe5c1c JH |
460 | int sep = 0; |
461 | uschar *seen_items = NULL; | |
462 | int seen_items_size = 0; | |
463 | int seen_items_offset = 0; | |
1cfe5c1c JH |
464 | uschar *dkim_canon_expanded; |
465 | uschar *dkim_sign_headers_expanded; | |
466 | uschar *dkim_private_key_expanded; | |
467 | pdkim_ctx *ctx = NULL; | |
468 | uschar *rc = NULL; | |
469 | uschar *sigbuf = NULL; | |
470 | int sigsize = 0; | |
471 | int sigptr = 0; | |
472 | pdkim_signature *signature; | |
473 | int pdkim_canon; | |
474 | int pdkim_rc; | |
475 | int sread; | |
476 | char buf[4096]; | |
477 | int save_errno = 0; | |
478 | int old_pool = store_pool; | |
479 | ||
480 | store_pool = POOL_MAIN; | |
481 | ||
e983e85a | 482 | if (!(dkim_domain = expand_cstring(dkim->dkim_domain))) |
1cfe5c1c JH |
483 | { |
484 | /* expansion error, do not send message. */ | |
485 | log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand " | |
486 | "dkim_domain: %s", expand_string_message); | |
f7302073 | 487 | goto bad; |
1cfe5c1c JH |
488 | } |
489 | ||
490 | /* Set $dkim_domain expansion variable to each unique domain in list. */ | |
491 | ||
42055a33 | 492 | while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, NULL, 0))) |
1cfe5c1c | 493 | { |
42055a33 | 494 | if (dkim_signing_domain[0] == '\0') |
1cfe5c1c JH |
495 | continue; |
496 | ||
497 | /* Only sign once for each domain, no matter how often it | |
498 | appears in the expanded list. */ | |
499 | ||
500 | if (seen_items) | |
501 | { | |
502 | const uschar *seen_items_list = seen_items; | |
503 | if (match_isinlist(dkim_signing_domain, | |
504 | &seen_items_list, 0, NULL, NULL, MCL_STRING, TRUE, | |
505 | NULL) == OK) | |
506 | continue; | |
507 | ||
508 | seen_items = | |
509 | string_append(seen_items, &seen_items_size, &seen_items_offset, 1, ":"); | |
510 | } | |
511 | ||
512 | seen_items = | |
513 | string_append(seen_items, &seen_items_size, &seen_items_offset, 1, | |
514 | dkim_signing_domain); | |
515 | seen_items[seen_items_offset] = '\0'; | |
516 | ||
517 | /* Set up $dkim_selector expansion variable. */ | |
518 | ||
e983e85a | 519 | if (!(dkim_signing_selector = expand_string(dkim->dkim_selector))) |
1cfe5c1c JH |
520 | { |
521 | log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand " | |
522 | "dkim_selector: %s", expand_string_message); | |
f7302073 | 523 | goto bad; |
1cfe5c1c JH |
524 | } |
525 | ||
526 | /* Get canonicalization to use */ | |
527 | ||
e983e85a JH |
528 | dkim_canon_expanded = dkim->dkim_canon |
529 | ? expand_string(dkim->dkim_canon) : US"relaxed"; | |
1cfe5c1c JH |
530 | if (!dkim_canon_expanded) |
531 | { | |
80a47a2c | 532 | /* expansion error, do not send message. */ |
1cfe5c1c JH |
533 | log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand " |
534 | "dkim_canon: %s", expand_string_message); | |
f7302073 | 535 | goto bad; |
1cfe5c1c | 536 | } |
80a47a2c | 537 | |
1cfe5c1c JH |
538 | if (Ustrcmp(dkim_canon_expanded, "relaxed") == 0) |
539 | pdkim_canon = PDKIM_CANON_RELAXED; | |
540 | else if (Ustrcmp(dkim_canon_expanded, "simple") == 0) | |
541 | pdkim_canon = PDKIM_CANON_SIMPLE; | |
542 | else | |
543 | { | |
544 | log_write(0, LOG_MAIN, | |
545 | "DKIM: unknown canonicalization method '%s', defaulting to 'relaxed'.\n", | |
546 | dkim_canon_expanded); | |
547 | pdkim_canon = PDKIM_CANON_RELAXED; | |
a8e1eeba | 548 | } |
1cfe5c1c JH |
549 | |
550 | dkim_sign_headers_expanded = NULL; | |
e983e85a JH |
551 | if (dkim->dkim_sign_headers) |
552 | if (!(dkim_sign_headers_expanded = expand_string(dkim->dkim_sign_headers))) | |
1cfe5c1c JH |
553 | { |
554 | log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand " | |
555 | "dkim_sign_headers: %s", expand_string_message); | |
f7302073 | 556 | goto bad; |
1cfe5c1c JH |
557 | } |
558 | /* else pass NULL, which means default header list */ | |
559 | ||
560 | /* Get private key to use. */ | |
561 | ||
e983e85a | 562 | if (!(dkim_private_key_expanded = expand_string(dkim->dkim_private_key))) |
1cfe5c1c JH |
563 | { |
564 | log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand " | |
565 | "dkim_private_key: %s", expand_string_message); | |
f7302073 | 566 | goto bad; |
a8e1eeba | 567 | } |
80a47a2c | 568 | |
1cfe5c1c JH |
569 | if ( Ustrlen(dkim_private_key_expanded) == 0 |
570 | || Ustrcmp(dkim_private_key_expanded, "0") == 0 | |
571 | || Ustrcmp(dkim_private_key_expanded, "false") == 0 | |
572 | ) | |
573 | continue; /* don't sign, but no error */ | |
574 | ||
575 | if (dkim_private_key_expanded[0] == '/') | |
576 | { | |
59d98039 | 577 | int privkey_fd, off = 0, len; |
1cfe5c1c JH |
578 | |
579 | /* Looks like a filename, load the private key. */ | |
580 | ||
581 | memset(big_buffer, 0, big_buffer_size); | |
e983e85a JH |
582 | |
583 | if ((privkey_fd = open(CS dkim_private_key_expanded, O_RDONLY)) < 0) | |
1cfe5c1c JH |
584 | { |
585 | log_write(0, LOG_MAIN | LOG_PANIC, "unable to open " | |
586 | "private key file for reading: %s", | |
587 | dkim_private_key_expanded); | |
f7302073 | 588 | goto bad; |
db4d0902 | 589 | } |
80a47a2c | 590 | |
59d98039 | 591 | do |
1cfe5c1c | 592 | { |
59d98039 JH |
593 | if ((len = read(privkey_fd, big_buffer + off, big_buffer_size - 2 - off)) < 0) |
594 | { | |
595 | (void) close(privkey_fd); | |
596 | log_write(0, LOG_MAIN|LOG_PANIC, "unable to read private key file: %s", | |
597 | dkim_private_key_expanded); | |
598 | goto bad; | |
599 | } | |
600 | off += len; | |
1ac6b2e7 | 601 | } |
59d98039 | 602 | while (len > 0); |
80a47a2c | 603 | |
1cfe5c1c | 604 | (void) close(privkey_fd); |
59d98039 | 605 | big_buffer[off] = '\0'; |
1cfe5c1c | 606 | dkim_private_key_expanded = big_buffer; |
a8e1eeba | 607 | } |
1cfe5c1c | 608 | |
b9df1829 | 609 | if (!(ctx = pdkim_init_sign(CS dkim_signing_domain, |
cd1a5fe0 JH |
610 | CS dkim_signing_selector, |
611 | CS dkim_private_key_expanded, | |
612 | PDKIM_ALGO_RSA_SHA256, | |
613 | dkim->dot_stuffed, | |
b9df1829 JH |
614 | &dkim_exim_query_dns_txt, |
615 | errstr | |
616 | ))) | |
617 | goto bad; | |
87cb4a16 | 618 | dkim_private_key_expanded[0] = '\0'; |
1cfe5c1c | 619 | pdkim_set_optional(ctx, |
e983e85a | 620 | CS dkim_sign_headers_expanded, |
1cfe5c1c JH |
621 | NULL, |
622 | pdkim_canon, | |
f444c2c7 | 623 | pdkim_canon, -1, 0, 0); |
1cfe5c1c | 624 | |
42055a33 JH |
625 | if (prefix) |
626 | pdkim_feed(ctx, prefix, Ustrlen(prefix)); | |
627 | ||
d315eda1 JH |
628 | if (lseek(fd, off, SEEK_SET) < 0) |
629 | sread = -1; | |
630 | else | |
631 | while ((sread = read(fd, &buf, sizeof(buf))) > 0) | |
632 | if ((pdkim_rc = pdkim_feed(ctx, buf, sread)) != PDKIM_OK) | |
633 | goto pk_bad; | |
1cfe5c1c JH |
634 | |
635 | /* Handle failed read above. */ | |
636 | if (sread == -1) | |
637 | { | |
638 | debug_printf("DKIM: Error reading -K file.\n"); | |
639 | save_errno = errno; | |
f7302073 | 640 | goto bad; |
80a47a2c | 641 | } |
80a47a2c | 642 | |
b9df1829 | 643 | if ((pdkim_rc = pdkim_feed_finish(ctx, &signature, errstr)) != PDKIM_OK) |
f7302073 | 644 | goto pk_bad; |
80a47a2c | 645 | |
1cfe5c1c JH |
646 | sigbuf = string_append(sigbuf, &sigsize, &sigptr, 2, |
647 | US signature->signature_header, US"\r\n"); | |
80a47a2c | 648 | |
1cfe5c1c JH |
649 | pdkim_free_ctx(ctx); |
650 | ctx = NULL; | |
80a47a2c | 651 | } |
a8e1eeba | 652 | |
1cfe5c1c JH |
653 | if (sigbuf) |
654 | { | |
655 | sigbuf[sigptr] = '\0'; | |
656 | rc = sigbuf; | |
657 | } | |
658 | else | |
659 | rc = US""; | |
660 | ||
661 | CLEANUP: | |
f7302073 JH |
662 | if (ctx) |
663 | pdkim_free_ctx(ctx); | |
664 | store_pool = old_pool; | |
665 | errno = save_errno; | |
666 | return rc; | |
667 | ||
668 | pk_bad: | |
669 | log_write(0, LOG_MAIN|LOG_PANIC, | |
670 | "DKIM: signing failed: %.100s", pdkim_errstr(pdkim_rc)); | |
671 | bad: | |
672 | rc = NULL; | |
673 | goto CLEANUP; | |
93f2d376 | 674 | } |
80a47a2c TK |
675 | |
676 | #endif |