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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 | |
d73e45df JH |
23 | |
24 | ||
25 | /*XXX the caller only uses the first record if we return multiple. | |
26 | Could we hand back an allocated string? | |
27 | */ | |
28 | ||
1cfe5c1c JH |
29 | static int |
30 | dkim_exim_query_dns_txt(char *name, char *answer) | |
31 | { | |
32 | dns_answer dnsa; | |
33 | dns_scan dnss; | |
34 | dns_record *rr; | |
80a47a2c | 35 | |
1cfe5c1c JH |
36 | lookup_dnssec_authenticated = NULL; |
37 | if (dns_lookup(&dnsa, US name, T_TXT, NULL) != DNS_SUCCEED) | |
f7302073 | 38 | return PDKIM_FAIL; /*XXX better error detail? logging? */ |
80a47a2c | 39 | |
1cfe5c1c | 40 | /* Search for TXT record */ |
80a47a2c | 41 | |
1cfe5c1c JH |
42 | for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS); |
43 | rr; | |
44 | rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) | |
45 | if (rr->type == T_TXT) | |
46 | { | |
80a47a2c TK |
47 | int rr_offset = 0; |
48 | int answer_offset = 0; | |
1cfe5c1c JH |
49 | |
50 | /* Copy record content to the answer buffer */ | |
51 | ||
52 | while (rr_offset < rr->size) | |
53 | { | |
54 | uschar len = rr->data[rr_offset++]; | |
55 | snprintf(answer + answer_offset, | |
56 | PDKIM_DNS_TXT_MAX_RECLEN - answer_offset, | |
5903c6ff | 57 | "%.*s", (int)len, CS (rr->data + rr_offset)); |
1cfe5c1c JH |
58 | rr_offset += len; |
59 | answer_offset += len; | |
60 | if (answer_offset >= PDKIM_DNS_TXT_MAX_RECLEN) | |
f7302073 | 61 | return PDKIM_FAIL; /*XXX better error detail? logging? */ |
4263f395 | 62 | } |
1cfe5c1c | 63 | return PDKIM_OK; |
80a47a2c | 64 | } |
80a47a2c | 65 | |
f7302073 | 66 | return PDKIM_FAIL; /*XXX better error detail? logging? */ |
80a47a2c TK |
67 | } |
68 | ||
69 | ||
2592e6c0 JH |
70 | void |
71 | dkim_exim_init(void) | |
72 | { | |
73 | pdkim_init(); | |
74 | } | |
75 | ||
76 | ||
ca9cb170 | 77 | |
1cfe5c1c | 78 | void |
e983e85a | 79 | dkim_exim_verify_init(BOOL dot_stuffing) |
1cfe5c1c | 80 | { |
ca9cb170 JH |
81 | /* There is a store-reset between header & body reception |
82 | so cannot use the main pool. Any allocs done by Exim | |
83 | memory-handling must use the perm pool. */ | |
84 | ||
85 | dkim_verify_oldpool = store_pool; | |
86 | store_pool = POOL_PERM; | |
87 | ||
1cfe5c1c | 88 | /* Free previous context if there is one */ |
80a47a2c | 89 | |
1cfe5c1c JH |
90 | if (dkim_verify_ctx) |
91 | pdkim_free_ctx(dkim_verify_ctx); | |
80a47a2c | 92 | |
1cfe5c1c | 93 | /* Create new context */ |
80a47a2c | 94 | |
e983e85a | 95 | dkim_verify_ctx = pdkim_init_verify(&dkim_exim_query_dns_txt, dot_stuffing); |
3b957582 | 96 | dkim_collect_input = !!dkim_verify_ctx; |
b9df1829 | 97 | dkim_collect_error = NULL; |
ca9cb170 | 98 | |
584e96c6 JH |
99 | /* Start feed up with any cached data */ |
100 | receive_get_cache(); | |
101 | ||
ca9cb170 | 102 | store_pool = dkim_verify_oldpool; |
80a47a2c TK |
103 | } |
104 | ||
105 | ||
1cfe5c1c JH |
106 | void |
107 | dkim_exim_verify_feed(uschar * data, int len) | |
108 | { | |
f7302073 JH |
109 | int rc; |
110 | ||
ca9cb170 | 111 | store_pool = POOL_PERM; |
1cfe5c1c | 112 | if ( dkim_collect_input |
ef698bf6 | 113 | && (rc = pdkim_feed(dkim_verify_ctx, data, len)) != PDKIM_OK) |
f7302073 | 114 | { |
b9df1829 | 115 | dkim_collect_error = pdkim_errstr(rc); |
f7302073 | 116 | log_write(0, LOG_MAIN, |
b9df1829 | 117 | "DKIM: validation error: %.100s", dkim_collect_error); |
1cfe5c1c | 118 | dkim_collect_input = FALSE; |
f7302073 | 119 | } |
ca9cb170 | 120 | store_pool = dkim_verify_oldpool; |
80a47a2c TK |
121 | } |
122 | ||
123 | ||
1cfe5c1c JH |
124 | void |
125 | dkim_exim_verify_finish(void) | |
126 | { | |
41468ba1 | 127 | pdkim_signature * sig = NULL; |
b9df1829 JH |
128 | int dkim_signers_size = 0, dkim_signers_ptr = 0, rc; |
129 | const uschar * errstr; | |
1cfe5c1c | 130 | |
ca9cb170 JH |
131 | store_pool = POOL_PERM; |
132 | ||
1cfe5c1c JH |
133 | /* Delete eventual previous signature chain */ |
134 | ||
41468ba1 | 135 | dkim_signers = NULL; |
1cfe5c1c JH |
136 | dkim_signatures = NULL; |
137 | ||
bd8fbe36 | 138 | if (dkim_collect_error) |
1cfe5c1c JH |
139 | { |
140 | log_write(0, LOG_MAIN, | |
b9df1829 JH |
141 | "DKIM: Error during validation, disabling signature verification: %.100s", |
142 | dkim_collect_error); | |
1cfe5c1c | 143 | dkim_disable_verify = TRUE; |
ca9cb170 | 144 | goto out; |
1cfe5c1c | 145 | } |
80a47a2c | 146 | |
1cfe5c1c | 147 | dkim_collect_input = FALSE; |
80a47a2c | 148 | |
1cfe5c1c | 149 | /* Finish DKIM operation and fetch link to signatures chain */ |
80a47a2c | 150 | |
b9df1829 JH |
151 | rc = pdkim_feed_finish(dkim_verify_ctx, &dkim_signatures, &errstr); |
152 | if (rc != PDKIM_OK) | |
f7302073 | 153 | { |
b9df1829 JH |
154 | log_write(0, LOG_MAIN, "DKIM: validation error: %.100s%s%s", pdkim_errstr(rc), |
155 | errstr ? ": " : "", errstr ? errstr : US""); | |
ca9cb170 | 156 | goto out; |
f7302073 | 157 | } |
1cfe5c1c JH |
158 | |
159 | for (sig = dkim_signatures; sig; sig = sig->next) | |
160 | { | |
41468ba1 JH |
161 | int size = 0, ptr = 0; |
162 | uschar * logmsg = NULL, * s; | |
1cfe5c1c JH |
163 | |
164 | /* Log a line for each signature */ | |
165 | ||
41468ba1 JH |
166 | if (!(s = sig->domain)) s = US"<UNSET>"; |
167 | logmsg = string_append(logmsg, &size, &ptr, 2, "d=", s); | |
168 | if (!(s = sig->selector)) s = US"<UNSET>"; | |
169 | logmsg = string_append(logmsg, &size, &ptr, 2, " s=", s); | |
170 | logmsg = string_append(logmsg, &size, &ptr, 7, | |
171 | " c=", sig->canon_headers == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", | |
172 | "/", sig->canon_body == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", | |
d73e45df | 173 | " a=", dkim_sig_to_a_tag(sig), |
41468ba1 JH |
174 | string_sprintf(" b=%d", |
175 | (int)sig->sighash.len > -1 ? sig->sighash.len * 8 : 0)); | |
31323b30 HSHR |
176 | if ((s= sig->identity)) logmsg = string_append(logmsg, &size, &ptr, 2, " i=", s); |
177 | if (sig->created > 0) logmsg = string_append(logmsg, &size, &ptr, 1, | |
41468ba1 | 178 | string_sprintf(" t=%lu", sig->created)); |
31323b30 | 179 | if (sig->expires > 0) logmsg = string_append(logmsg, &size, &ptr, 1, |
41468ba1 | 180 | string_sprintf(" x=%lu", sig->expires)); |
31323b30 | 181 | if (sig->bodylength > -1) logmsg = string_append(logmsg, &size, &ptr, 1, |
41468ba1 | 182 | string_sprintf(" l=%lu", sig->bodylength)); |
1cfe5c1c JH |
183 | |
184 | switch (sig->verify_status) | |
185 | { | |
186 | case PDKIM_VERIFY_NONE: | |
41468ba1 | 187 | logmsg = string_append(logmsg, &size, &ptr, 1, " [not verified]"); |
80a47a2c | 188 | break; |
1cfe5c1c JH |
189 | |
190 | case PDKIM_VERIFY_INVALID: | |
41468ba1 | 191 | logmsg = string_append(logmsg, &size, &ptr, 1, " [invalid - "); |
1cfe5c1c JH |
192 | switch (sig->verify_ext_status) |
193 | { | |
194 | case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: | |
195 | logmsg = string_append(logmsg, &size, &ptr, 1, | |
196 | "public key record (currently?) unavailable]"); | |
197 | break; | |
198 | ||
199 | case PDKIM_VERIFY_INVALID_BUFFER_SIZE: | |
200 | logmsg = string_append(logmsg, &size, &ptr, 1, | |
201 | "overlong public key record]"); | |
202 | break; | |
203 | ||
df3def24 JH |
204 | case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: |
205 | case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: | |
1cfe5c1c JH |
206 | logmsg = string_append(logmsg, &size, &ptr, 1, |
207 | "syntax error in public key record]"); | |
208 | break; | |
07eeb4df | 209 | |
210 | case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: | |
211 | logmsg = string_append(logmsg, &size, &ptr, 1, | |
212 | "signature tag missing or invalid]"); | |
213 | break; | |
214 | ||
215 | case PDKIM_VERIFY_INVALID_DKIM_VERSION: | |
216 | logmsg = string_append(logmsg, &size, &ptr, 1, | |
217 | "unsupported DKIM version]"); | |
218 | break; | |
1cfe5c1c JH |
219 | |
220 | default: | |
221 | logmsg = string_append(logmsg, &size, &ptr, 1, | |
222 | "unspecified problem]"); | |
223 | } | |
80a47a2c | 224 | break; |
1cfe5c1c JH |
225 | |
226 | case PDKIM_VERIFY_FAIL: | |
227 | logmsg = | |
41468ba1 | 228 | string_append(logmsg, &size, &ptr, 1, " [verification failed - "); |
1cfe5c1c JH |
229 | switch (sig->verify_ext_status) |
230 | { | |
231 | case PDKIM_VERIFY_FAIL_BODY: | |
232 | logmsg = string_append(logmsg, &size, &ptr, 1, | |
233 | "body hash mismatch (body probably modified in transit)]"); | |
234 | break; | |
235 | ||
236 | case PDKIM_VERIFY_FAIL_MESSAGE: | |
237 | logmsg = string_append(logmsg, &size, &ptr, 1, | |
238 | "signature did not verify (headers probably modified in transit)]"); | |
239 | break; | |
240 | ||
241 | default: | |
242 | logmsg = string_append(logmsg, &size, &ptr, 1, "unspecified reason]"); | |
243 | } | |
80a47a2c | 244 | break; |
1cfe5c1c JH |
245 | |
246 | case PDKIM_VERIFY_PASS: | |
247 | logmsg = | |
41468ba1 | 248 | string_append(logmsg, &size, &ptr, 1, " [verification succeeded]"); |
80a47a2c TK |
249 | break; |
250 | } | |
251 | ||
1cfe5c1c JH |
252 | logmsg[ptr] = '\0'; |
253 | log_write(0, LOG_MAIN, "DKIM: %s", logmsg); | |
80a47a2c | 254 | |
1cfe5c1c JH |
255 | /* Build a colon-separated list of signing domains (and identities, if present) in dkim_signers */ |
256 | ||
41468ba1 | 257 | if (sig->domain) |
4226691b JH |
258 | dkim_signers = string_append_listele(dkim_signers, &dkim_signers_size, |
259 | &dkim_signers_ptr, ':', sig->domain); | |
1cfe5c1c JH |
260 | |
261 | if (sig->identity) | |
4226691b JH |
262 | dkim_signers = string_append_listele(dkim_signers, &dkim_signers_size, |
263 | &dkim_signers_ptr, ':', sig->identity); | |
80a47a2c | 264 | |
1cfe5c1c | 265 | /* Process next signature */ |
80a47a2c TK |
266 | } |
267 | ||
ca9cb170 JH |
268 | out: |
269 | store_pool = dkim_verify_oldpool; | |
80a47a2c TK |
270 | } |
271 | ||
272 | ||
1cfe5c1c JH |
273 | void |
274 | dkim_exim_acl_setup(uschar * id) | |
275 | { | |
276 | pdkim_signature * sig; | |
277 | uschar * cmp_val; | |
278 | ||
1cfe5c1c JH |
279 | dkim_cur_sig = NULL; |
280 | dkim_cur_signer = id; | |
281 | ||
282 | if (dkim_disable_verify || !id || !dkim_verify_ctx) | |
283 | return; | |
284 | ||
285 | /* Find signature to run ACL on */ | |
286 | ||
287 | for (sig = dkim_signatures; sig; sig = sig->next) | |
288 | if ( (cmp_val = Ustrchr(id, '@') != NULL ? US sig->identity : US sig->domain) | |
289 | && strcmpic(cmp_val, id) == 0 | |
290 | ) | |
291 | { | |
292 | dkim_cur_sig = sig; | |
293 | ||
294 | /* The "dkim_domain" and "dkim_selector" expansion variables have | |
295 | related globals, since they are used in the signing code too. | |
296 | Instead of inventing separate names for verification, we set | |
297 | them here. This is easy since a domain and selector is guaranteed | |
298 | to be in a signature. The other dkim_* expansion items are | |
299 | dynamically fetched from dkim_cur_sig at expansion time (see | |
300 | function below). */ | |
301 | ||
302 | dkim_signing_domain = US sig->domain; | |
303 | dkim_signing_selector = US sig->selector; | |
dcd03763 | 304 | dkim_key_length = sig->sighash.len * 8; |
1cfe5c1c | 305 | return; |
80a47a2c | 306 | } |
80a47a2c TK |
307 | } |
308 | ||
309 | ||
1cfe5c1c JH |
310 | static uschar * |
311 | dkim_exim_expand_defaults(int what) | |
312 | { | |
313 | switch (what) | |
314 | { | |
315 | case DKIM_ALGO: return US""; | |
316 | case DKIM_BODYLENGTH: return US"9999999999999"; | |
317 | case DKIM_CANON_BODY: return US""; | |
318 | case DKIM_CANON_HEADERS: return US""; | |
319 | case DKIM_COPIEDHEADERS: return US""; | |
320 | case DKIM_CREATED: return US"0"; | |
321 | case DKIM_EXPIRES: return US"9999999999999"; | |
322 | case DKIM_HEADERNAMES: return US""; | |
323 | case DKIM_IDENTITY: return US""; | |
324 | case DKIM_KEY_GRANULARITY: return US"*"; | |
325 | case DKIM_KEY_SRVTYPE: return US"*"; | |
326 | case DKIM_KEY_NOTES: return US""; | |
327 | case DKIM_KEY_TESTING: return US"0"; | |
328 | case DKIM_NOSUBDOMAINS: return US"0"; | |
329 | case DKIM_VERIFY_STATUS: return US"none"; | |
330 | case DKIM_VERIFY_REASON: return US""; | |
331 | default: return US""; | |
332 | } | |
333 | } | |
80a47a2c | 334 | |
80a47a2c | 335 | |
1cfe5c1c JH |
336 | uschar * |
337 | dkim_exim_expand_query(int what) | |
338 | { | |
339 | if (!dkim_verify_ctx || dkim_disable_verify || !dkim_cur_sig) | |
340 | return dkim_exim_expand_defaults(what); | |
341 | ||
342 | switch (what) | |
343 | { | |
344 | case DKIM_ALGO: | |
d73e45df | 345 | return dkim_sig_to_a_tag(dkim_cur_sig); |
1cfe5c1c JH |
346 | |
347 | case DKIM_BODYLENGTH: | |
348 | return dkim_cur_sig->bodylength >= 0 | |
349 | ? string_sprintf(OFF_T_FMT, (LONGLONG_T) dkim_cur_sig->bodylength) | |
350 | : dkim_exim_expand_defaults(what); | |
351 | ||
352 | case DKIM_CANON_BODY: | |
353 | switch (dkim_cur_sig->canon_body) | |
354 | { | |
355 | case PDKIM_CANON_RELAXED: return US"relaxed"; | |
356 | case PDKIM_CANON_SIMPLE: | |
357 | default: return US"simple"; | |
80a47a2c | 358 | } |
1cfe5c1c JH |
359 | |
360 | case DKIM_CANON_HEADERS: | |
361 | switch (dkim_cur_sig->canon_headers) | |
362 | { | |
363 | case PDKIM_CANON_RELAXED: return US"relaxed"; | |
364 | case PDKIM_CANON_SIMPLE: | |
365 | default: return US"simple"; | |
366 | } | |
367 | ||
368 | case DKIM_COPIEDHEADERS: | |
369 | return dkim_cur_sig->copiedheaders | |
370 | ? US dkim_cur_sig->copiedheaders : dkim_exim_expand_defaults(what); | |
371 | ||
372 | case DKIM_CREATED: | |
373 | return dkim_cur_sig->created > 0 | |
374 | ? string_sprintf("%llu", dkim_cur_sig->created) | |
375 | : dkim_exim_expand_defaults(what); | |
376 | ||
377 | case DKIM_EXPIRES: | |
378 | return dkim_cur_sig->expires > 0 | |
379 | ? string_sprintf("%llu", dkim_cur_sig->expires) | |
380 | : dkim_exim_expand_defaults(what); | |
381 | ||
382 | case DKIM_HEADERNAMES: | |
383 | return dkim_cur_sig->headernames | |
2592e6c0 | 384 | ? dkim_cur_sig->headernames : dkim_exim_expand_defaults(what); |
1cfe5c1c JH |
385 | |
386 | case DKIM_IDENTITY: | |
387 | return dkim_cur_sig->identity | |
388 | ? US dkim_cur_sig->identity : dkim_exim_expand_defaults(what); | |
389 | ||
390 | case DKIM_KEY_GRANULARITY: | |
391 | return dkim_cur_sig->pubkey | |
392 | ? dkim_cur_sig->pubkey->granularity | |
393 | ? US dkim_cur_sig->pubkey->granularity | |
394 | : dkim_exim_expand_defaults(what) | |
395 | : dkim_exim_expand_defaults(what); | |
396 | ||
397 | case DKIM_KEY_SRVTYPE: | |
398 | return dkim_cur_sig->pubkey | |
399 | ? dkim_cur_sig->pubkey->srvtype | |
400 | ? US dkim_cur_sig->pubkey->srvtype | |
401 | : dkim_exim_expand_defaults(what) | |
402 | : dkim_exim_expand_defaults(what); | |
403 | ||
404 | case DKIM_KEY_NOTES: | |
405 | return dkim_cur_sig->pubkey | |
406 | ? dkim_cur_sig->pubkey->notes | |
407 | ? US dkim_cur_sig->pubkey->notes | |
408 | : dkim_exim_expand_defaults(what) | |
409 | : dkim_exim_expand_defaults(what); | |
410 | ||
411 | case DKIM_KEY_TESTING: | |
412 | return dkim_cur_sig->pubkey | |
413 | ? dkim_cur_sig->pubkey->testing | |
414 | ? US"1" | |
415 | : dkim_exim_expand_defaults(what) | |
416 | : dkim_exim_expand_defaults(what); | |
417 | ||
418 | case DKIM_NOSUBDOMAINS: | |
419 | return dkim_cur_sig->pubkey | |
420 | ? dkim_cur_sig->pubkey->no_subdomaining | |
421 | ? US"1" | |
422 | : dkim_exim_expand_defaults(what) | |
423 | : dkim_exim_expand_defaults(what); | |
424 | ||
425 | case DKIM_VERIFY_STATUS: | |
426 | switch (dkim_cur_sig->verify_status) | |
427 | { | |
428 | case PDKIM_VERIFY_INVALID: return US"invalid"; | |
429 | case PDKIM_VERIFY_FAIL: return US"fail"; | |
430 | case PDKIM_VERIFY_PASS: return US"pass"; | |
431 | case PDKIM_VERIFY_NONE: | |
432 | default: return US"none"; | |
80a47a2c | 433 | } |
80a47a2c | 434 | |
1cfe5c1c JH |
435 | case DKIM_VERIFY_REASON: |
436 | switch (dkim_cur_sig->verify_ext_status) | |
437 | { | |
438 | case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: | |
439 | return US"pubkey_unavailable"; | |
df3def24 JH |
440 | case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD:return US"pubkey_dns_syntax"; |
441 | case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: return US"pubkey_der_syntax"; | |
1cfe5c1c JH |
442 | case PDKIM_VERIFY_FAIL_BODY: return US"bodyhash_mismatch"; |
443 | case PDKIM_VERIFY_FAIL_MESSAGE: return US"signature_incorrect"; | |
444 | } | |
80a47a2c | 445 | |
1cfe5c1c JH |
446 | default: |
447 | return US""; | |
80a47a2c TK |
448 | } |
449 | } | |
450 | ||
451 | ||
42055a33 JH |
452 | /* Generate signatures for the given file, returning a string. |
453 | If a prefix is given, prepend it to the file for the calculations. | |
454 | */ | |
455 | ||
55414b25 | 456 | uschar * |
42055a33 JH |
457 | dkim_exim_sign(int fd, off_t off, uschar * prefix, |
458 | struct ob_dkim * dkim, const uschar ** errstr) | |
55414b25 | 459 | { |
e983e85a | 460 | const uschar * dkim_domain; |
1cfe5c1c JH |
461 | int sep = 0; |
462 | uschar *seen_items = NULL; | |
463 | int seen_items_size = 0; | |
464 | int seen_items_offset = 0; | |
1cfe5c1c JH |
465 | uschar *dkim_canon_expanded; |
466 | uschar *dkim_sign_headers_expanded; | |
467 | uschar *dkim_private_key_expanded; | |
d73e45df | 468 | uschar *dkim_hash_expanded; |
1cfe5c1c JH |
469 | pdkim_ctx *ctx = NULL; |
470 | uschar *rc = NULL; | |
471 | uschar *sigbuf = NULL; | |
472 | int sigsize = 0; | |
473 | int sigptr = 0; | |
474 | pdkim_signature *signature; | |
475 | int pdkim_canon; | |
476 | int pdkim_rc; | |
477 | int sread; | |
ef698bf6 | 478 | uschar buf[4096]; |
1cfe5c1c JH |
479 | int save_errno = 0; |
480 | int old_pool = store_pool; | |
481 | ||
482 | store_pool = POOL_MAIN; | |
483 | ||
e983e85a | 484 | if (!(dkim_domain = expand_cstring(dkim->dkim_domain))) |
1cfe5c1c JH |
485 | { |
486 | /* expansion error, do not send message. */ | |
487 | log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand " | |
488 | "dkim_domain: %s", expand_string_message); | |
f7302073 | 489 | goto bad; |
1cfe5c1c JH |
490 | } |
491 | ||
492 | /* Set $dkim_domain expansion variable to each unique domain in list. */ | |
493 | ||
42055a33 | 494 | while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, NULL, 0))) |
1cfe5c1c | 495 | { |
42055a33 | 496 | if (dkim_signing_domain[0] == '\0') |
1cfe5c1c JH |
497 | continue; |
498 | ||
499 | /* Only sign once for each domain, no matter how often it | |
500 | appears in the expanded list. */ | |
501 | ||
502 | if (seen_items) | |
503 | { | |
504 | const uschar *seen_items_list = seen_items; | |
505 | if (match_isinlist(dkim_signing_domain, | |
506 | &seen_items_list, 0, NULL, NULL, MCL_STRING, TRUE, | |
507 | NULL) == OK) | |
508 | continue; | |
509 | ||
510 | seen_items = | |
511 | string_append(seen_items, &seen_items_size, &seen_items_offset, 1, ":"); | |
512 | } | |
513 | ||
514 | seen_items = | |
515 | string_append(seen_items, &seen_items_size, &seen_items_offset, 1, | |
516 | dkim_signing_domain); | |
517 | seen_items[seen_items_offset] = '\0'; | |
518 | ||
519 | /* Set up $dkim_selector expansion variable. */ | |
520 | ||
e983e85a | 521 | if (!(dkim_signing_selector = expand_string(dkim->dkim_selector))) |
1cfe5c1c JH |
522 | { |
523 | log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand " | |
524 | "dkim_selector: %s", expand_string_message); | |
f7302073 | 525 | goto bad; |
1cfe5c1c JH |
526 | } |
527 | ||
528 | /* Get canonicalization to use */ | |
529 | ||
e983e85a JH |
530 | dkim_canon_expanded = dkim->dkim_canon |
531 | ? expand_string(dkim->dkim_canon) : US"relaxed"; | |
1cfe5c1c JH |
532 | if (!dkim_canon_expanded) |
533 | { | |
80a47a2c | 534 | /* expansion error, do not send message. */ |
1cfe5c1c JH |
535 | log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand " |
536 | "dkim_canon: %s", expand_string_message); | |
f7302073 | 537 | goto bad; |
1cfe5c1c | 538 | } |
80a47a2c | 539 | |
1cfe5c1c JH |
540 | if (Ustrcmp(dkim_canon_expanded, "relaxed") == 0) |
541 | pdkim_canon = PDKIM_CANON_RELAXED; | |
542 | else if (Ustrcmp(dkim_canon_expanded, "simple") == 0) | |
543 | pdkim_canon = PDKIM_CANON_SIMPLE; | |
544 | else | |
545 | { | |
546 | log_write(0, LOG_MAIN, | |
547 | "DKIM: unknown canonicalization method '%s', defaulting to 'relaxed'.\n", | |
548 | dkim_canon_expanded); | |
549 | pdkim_canon = PDKIM_CANON_RELAXED; | |
a8e1eeba | 550 | } |
1cfe5c1c JH |
551 | |
552 | dkim_sign_headers_expanded = NULL; | |
e983e85a JH |
553 | if (dkim->dkim_sign_headers) |
554 | if (!(dkim_sign_headers_expanded = expand_string(dkim->dkim_sign_headers))) | |
1cfe5c1c JH |
555 | { |
556 | log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand " | |
557 | "dkim_sign_headers: %s", expand_string_message); | |
f7302073 | 558 | goto bad; |
1cfe5c1c JH |
559 | } |
560 | /* else pass NULL, which means default header list */ | |
561 | ||
562 | /* Get private key to use. */ | |
563 | ||
e983e85a | 564 | if (!(dkim_private_key_expanded = expand_string(dkim->dkim_private_key))) |
1cfe5c1c JH |
565 | { |
566 | log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand " | |
567 | "dkim_private_key: %s", expand_string_message); | |
f7302073 | 568 | goto bad; |
a8e1eeba | 569 | } |
80a47a2c | 570 | |
1cfe5c1c JH |
571 | if ( Ustrlen(dkim_private_key_expanded) == 0 |
572 | || Ustrcmp(dkim_private_key_expanded, "0") == 0 | |
573 | || Ustrcmp(dkim_private_key_expanded, "false") == 0 | |
574 | ) | |
575 | continue; /* don't sign, but no error */ | |
576 | ||
577 | if (dkim_private_key_expanded[0] == '/') | |
578 | { | |
59d98039 | 579 | int privkey_fd, off = 0, len; |
1cfe5c1c JH |
580 | |
581 | /* Looks like a filename, load the private key. */ | |
582 | ||
583 | memset(big_buffer, 0, big_buffer_size); | |
e983e85a JH |
584 | |
585 | if ((privkey_fd = open(CS dkim_private_key_expanded, O_RDONLY)) < 0) | |
1cfe5c1c JH |
586 | { |
587 | log_write(0, LOG_MAIN | LOG_PANIC, "unable to open " | |
588 | "private key file for reading: %s", | |
589 | dkim_private_key_expanded); | |
f7302073 | 590 | goto bad; |
db4d0902 | 591 | } |
80a47a2c | 592 | |
59d98039 | 593 | do |
1cfe5c1c | 594 | { |
59d98039 JH |
595 | if ((len = read(privkey_fd, big_buffer + off, big_buffer_size - 2 - off)) < 0) |
596 | { | |
597 | (void) close(privkey_fd); | |
598 | log_write(0, LOG_MAIN|LOG_PANIC, "unable to read private key file: %s", | |
599 | dkim_private_key_expanded); | |
600 | goto bad; | |
601 | } | |
602 | off += len; | |
1ac6b2e7 | 603 | } |
59d98039 | 604 | while (len > 0); |
80a47a2c | 605 | |
1cfe5c1c | 606 | (void) close(privkey_fd); |
59d98039 | 607 | big_buffer[off] = '\0'; |
1cfe5c1c | 608 | dkim_private_key_expanded = big_buffer; |
a8e1eeba | 609 | } |
1cfe5c1c | 610 | |
d73e45df JH |
611 | if (!(dkim_hash_expanded = expand_string(dkim->dkim_hash))) |
612 | { | |
613 | log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand " | |
614 | "dkim_hash: %s", expand_string_message); | |
615 | goto bad; | |
616 | } | |
617 | ||
618 | /*XXX so we currently nail signing to RSA + given hash. | |
619 | Need to extract algo from privkey and check for disallowed combos. */ | |
9b2583c4 | 620 | |
d73e45df JH |
621 | if (!(ctx = pdkim_init_sign(dkim_signing_domain, |
622 | dkim_signing_selector, | |
623 | dkim_private_key_expanded, | |
624 | dkim_hash_expanded, | |
cd1a5fe0 | 625 | dkim->dot_stuffed, |
b9df1829 JH |
626 | &dkim_exim_query_dns_txt, |
627 | errstr | |
628 | ))) | |
629 | goto bad; | |
87cb4a16 | 630 | dkim_private_key_expanded[0] = '\0'; |
1cfe5c1c | 631 | pdkim_set_optional(ctx, |
e983e85a | 632 | CS dkim_sign_headers_expanded, |
1cfe5c1c JH |
633 | NULL, |
634 | pdkim_canon, | |
f444c2c7 | 635 | pdkim_canon, -1, 0, 0); |
1cfe5c1c | 636 | |
42055a33 JH |
637 | if (prefix) |
638 | pdkim_feed(ctx, prefix, Ustrlen(prefix)); | |
639 | ||
d315eda1 JH |
640 | if (lseek(fd, off, SEEK_SET) < 0) |
641 | sread = -1; | |
642 | else | |
643 | while ((sread = read(fd, &buf, sizeof(buf))) > 0) | |
644 | if ((pdkim_rc = pdkim_feed(ctx, buf, sread)) != PDKIM_OK) | |
645 | goto pk_bad; | |
1cfe5c1c JH |
646 | |
647 | /* Handle failed read above. */ | |
648 | if (sread == -1) | |
649 | { | |
650 | debug_printf("DKIM: Error reading -K file.\n"); | |
651 | save_errno = errno; | |
f7302073 | 652 | goto bad; |
80a47a2c | 653 | } |
80a47a2c | 654 | |
b9df1829 | 655 | if ((pdkim_rc = pdkim_feed_finish(ctx, &signature, errstr)) != PDKIM_OK) |
f7302073 | 656 | goto pk_bad; |
80a47a2c | 657 | |
1cfe5c1c JH |
658 | sigbuf = string_append(sigbuf, &sigsize, &sigptr, 2, |
659 | US signature->signature_header, US"\r\n"); | |
80a47a2c | 660 | |
1cfe5c1c JH |
661 | pdkim_free_ctx(ctx); |
662 | ctx = NULL; | |
80a47a2c | 663 | } |
a8e1eeba | 664 | |
1cfe5c1c JH |
665 | if (sigbuf) |
666 | { | |
667 | sigbuf[sigptr] = '\0'; | |
668 | rc = sigbuf; | |
669 | } | |
670 | else | |
671 | rc = US""; | |
672 | ||
673 | CLEANUP: | |
f7302073 JH |
674 | if (ctx) |
675 | pdkim_free_ctx(ctx); | |
676 | store_pool = old_pool; | |
677 | errno = save_errno; | |
678 | return rc; | |
679 | ||
680 | pk_bad: | |
681 | log_write(0, LOG_MAIN|LOG_PANIC, | |
682 | "DKIM: signing failed: %.100s", pdkim_errstr(pdkim_rc)); | |
683 | bad: | |
684 | rc = NULL; | |
685 | goto CLEANUP; | |
93f2d376 | 686 | } |
80a47a2c TK |
687 | |
688 | #endif |