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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 | 128 | int dkim_signers_size = 0, dkim_signers_ptr = 0, rc; |
94e1f16d | 129 | gstring * g = NULL; |
b9df1829 | 130 | const uschar * errstr; |
1cfe5c1c | 131 | |
ca9cb170 JH |
132 | store_pool = POOL_PERM; |
133 | ||
1cfe5c1c JH |
134 | /* Delete eventual previous signature chain */ |
135 | ||
41468ba1 | 136 | dkim_signers = NULL; |
1cfe5c1c JH |
137 | dkim_signatures = NULL; |
138 | ||
bd8fbe36 | 139 | if (dkim_collect_error) |
1cfe5c1c JH |
140 | { |
141 | log_write(0, LOG_MAIN, | |
b9df1829 JH |
142 | "DKIM: Error during validation, disabling signature verification: %.100s", |
143 | dkim_collect_error); | |
1cfe5c1c | 144 | dkim_disable_verify = TRUE; |
ca9cb170 | 145 | goto out; |
1cfe5c1c | 146 | } |
80a47a2c | 147 | |
1cfe5c1c | 148 | dkim_collect_input = FALSE; |
80a47a2c | 149 | |
1cfe5c1c | 150 | /* Finish DKIM operation and fetch link to signatures chain */ |
80a47a2c | 151 | |
b9df1829 JH |
152 | rc = pdkim_feed_finish(dkim_verify_ctx, &dkim_signatures, &errstr); |
153 | if (rc != PDKIM_OK) | |
f7302073 | 154 | { |
b9df1829 JH |
155 | log_write(0, LOG_MAIN, "DKIM: validation error: %.100s%s%s", pdkim_errstr(rc), |
156 | errstr ? ": " : "", errstr ? errstr : US""); | |
ca9cb170 | 157 | goto out; |
f7302073 | 158 | } |
1cfe5c1c JH |
159 | |
160 | for (sig = dkim_signatures; sig; sig = sig->next) | |
161 | { | |
94e1f16d JH |
162 | uschar * s; |
163 | gstring * logmsg; | |
1cfe5c1c JH |
164 | |
165 | /* Log a line for each signature */ | |
166 | ||
41468ba1 | 167 | if (!(s = sig->domain)) s = US"<UNSET>"; |
94e1f16d | 168 | logmsg = string_append(NULL, 2, "d=", s); |
41468ba1 | 169 | if (!(s = sig->selector)) s = US"<UNSET>"; |
94e1f16d JH |
170 | logmsg = string_append(logmsg, 2, " s=", s); |
171 | logmsg = string_append(logmsg, 7, | |
41468ba1 JH |
172 | " c=", sig->canon_headers == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", |
173 | "/", sig->canon_body == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", | |
d73e45df | 174 | " a=", dkim_sig_to_a_tag(sig), |
41468ba1 JH |
175 | string_sprintf(" b=%d", |
176 | (int)sig->sighash.len > -1 ? sig->sighash.len * 8 : 0)); | |
94e1f16d JH |
177 | if ((s= sig->identity)) logmsg = string_append(logmsg, 2, " i=", s); |
178 | if (sig->created > 0) logmsg = string_cat(logmsg, | |
41468ba1 | 179 | string_sprintf(" t=%lu", sig->created)); |
94e1f16d | 180 | if (sig->expires > 0) logmsg = string_cat(logmsg, |
41468ba1 | 181 | string_sprintf(" x=%lu", sig->expires)); |
94e1f16d | 182 | if (sig->bodylength > -1) logmsg = string_cat(logmsg, |
41468ba1 | 183 | string_sprintf(" l=%lu", sig->bodylength)); |
1cfe5c1c JH |
184 | |
185 | switch (sig->verify_status) | |
186 | { | |
187 | case PDKIM_VERIFY_NONE: | |
94e1f16d | 188 | logmsg = string_cat(logmsg, " [not verified]"); |
80a47a2c | 189 | break; |
1cfe5c1c JH |
190 | |
191 | case PDKIM_VERIFY_INVALID: | |
94e1f16d | 192 | logmsg = string_cat(logmsg, " [invalid - "); |
1cfe5c1c JH |
193 | switch (sig->verify_ext_status) |
194 | { | |
195 | case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: | |
94e1f16d | 196 | logmsg = string_cat(logmsg, |
1cfe5c1c JH |
197 | "public key record (currently?) unavailable]"); |
198 | break; | |
199 | ||
200 | case PDKIM_VERIFY_INVALID_BUFFER_SIZE: | |
94e1f16d | 201 | logmsg = string_cat(logmsg, "overlong public key record]"); |
1cfe5c1c JH |
202 | break; |
203 | ||
df3def24 JH |
204 | case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: |
205 | case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: | |
94e1f16d | 206 | logmsg = string_cat(logmsg, "syntax error in public key record]"); |
1cfe5c1c | 207 | break; |
07eeb4df | 208 | |
209 | case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: | |
94e1f16d | 210 | logmsg = string_cat(logmsg, "signature tag missing or invalid]"); |
07eeb4df | 211 | break; |
212 | ||
213 | case PDKIM_VERIFY_INVALID_DKIM_VERSION: | |
94e1f16d | 214 | logmsg = string_cat(logmsg, "unsupported DKIM version]"); |
07eeb4df | 215 | break; |
1cfe5c1c JH |
216 | |
217 | default: | |
94e1f16d | 218 | logmsg = string_cat(logmsg, "unspecified problem]"); |
1cfe5c1c | 219 | } |
80a47a2c | 220 | break; |
1cfe5c1c JH |
221 | |
222 | case PDKIM_VERIFY_FAIL: | |
223 | logmsg = | |
94e1f16d | 224 | string_cat(logmsg, " [verification failed - "); |
1cfe5c1c JH |
225 | switch (sig->verify_ext_status) |
226 | { | |
227 | case PDKIM_VERIFY_FAIL_BODY: | |
94e1f16d | 228 | logmsg = string_cat(logmsg, |
1cfe5c1c JH |
229 | "body hash mismatch (body probably modified in transit)]"); |
230 | break; | |
231 | ||
232 | case PDKIM_VERIFY_FAIL_MESSAGE: | |
94e1f16d | 233 | logmsg = string_cat(logmsg, |
1cfe5c1c JH |
234 | "signature did not verify (headers probably modified in transit)]"); |
235 | break; | |
236 | ||
237 | default: | |
94e1f16d | 238 | logmsg = string_cat(logmsg, "unspecified reason]"); |
1cfe5c1c | 239 | } |
80a47a2c | 240 | break; |
1cfe5c1c JH |
241 | |
242 | case PDKIM_VERIFY_PASS: | |
94e1f16d | 243 | logmsg = string_cat(logmsg, " [verification succeeded]"); |
80a47a2c TK |
244 | break; |
245 | } | |
246 | ||
94e1f16d | 247 | log_write(0, LOG_MAIN, "DKIM: %s", string_from_gstring(logmsg)); |
80a47a2c | 248 | |
1cfe5c1c JH |
249 | /* Build a colon-separated list of signing domains (and identities, if present) in dkim_signers */ |
250 | ||
41468ba1 | 251 | if (sig->domain) |
94e1f16d | 252 | g = string_append_listele(g, ':', sig->domain); |
1cfe5c1c JH |
253 | |
254 | if (sig->identity) | |
94e1f16d | 255 | g = string_append_listele(g, ':', sig->identity); |
80a47a2c | 256 | |
1cfe5c1c | 257 | /* Process next signature */ |
80a47a2c TK |
258 | } |
259 | ||
94e1f16d JH |
260 | if (g) dkim_signers = g->s; |
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: | |
d73e45df | 339 | return dkim_sig_to_a_tag(dkim_cur_sig); |
1cfe5c1c JH |
340 | |
341 | case DKIM_BODYLENGTH: | |
342 | return dkim_cur_sig->bodylength >= 0 | |
343 | ? string_sprintf(OFF_T_FMT, (LONGLONG_T) dkim_cur_sig->bodylength) | |
344 | : dkim_exim_expand_defaults(what); | |
345 | ||
346 | case DKIM_CANON_BODY: | |
347 | switch (dkim_cur_sig->canon_body) | |
348 | { | |
349 | case PDKIM_CANON_RELAXED: return US"relaxed"; | |
350 | case PDKIM_CANON_SIMPLE: | |
351 | default: return US"simple"; | |
80a47a2c | 352 | } |
1cfe5c1c JH |
353 | |
354 | case DKIM_CANON_HEADERS: | |
355 | switch (dkim_cur_sig->canon_headers) | |
356 | { | |
357 | case PDKIM_CANON_RELAXED: return US"relaxed"; | |
358 | case PDKIM_CANON_SIMPLE: | |
359 | default: return US"simple"; | |
360 | } | |
361 | ||
362 | case DKIM_COPIEDHEADERS: | |
363 | return dkim_cur_sig->copiedheaders | |
364 | ? US dkim_cur_sig->copiedheaders : dkim_exim_expand_defaults(what); | |
365 | ||
366 | case DKIM_CREATED: | |
367 | return dkim_cur_sig->created > 0 | |
368 | ? string_sprintf("%llu", dkim_cur_sig->created) | |
369 | : dkim_exim_expand_defaults(what); | |
370 | ||
371 | case DKIM_EXPIRES: | |
372 | return dkim_cur_sig->expires > 0 | |
373 | ? string_sprintf("%llu", dkim_cur_sig->expires) | |
374 | : dkim_exim_expand_defaults(what); | |
375 | ||
376 | case DKIM_HEADERNAMES: | |
377 | return dkim_cur_sig->headernames | |
2592e6c0 | 378 | ? dkim_cur_sig->headernames : dkim_exim_expand_defaults(what); |
1cfe5c1c JH |
379 | |
380 | case DKIM_IDENTITY: | |
381 | return dkim_cur_sig->identity | |
382 | ? US dkim_cur_sig->identity : dkim_exim_expand_defaults(what); | |
383 | ||
384 | case DKIM_KEY_GRANULARITY: | |
385 | return dkim_cur_sig->pubkey | |
386 | ? dkim_cur_sig->pubkey->granularity | |
387 | ? US dkim_cur_sig->pubkey->granularity | |
388 | : dkim_exim_expand_defaults(what) | |
389 | : dkim_exim_expand_defaults(what); | |
390 | ||
391 | case DKIM_KEY_SRVTYPE: | |
392 | return dkim_cur_sig->pubkey | |
393 | ? dkim_cur_sig->pubkey->srvtype | |
394 | ? US dkim_cur_sig->pubkey->srvtype | |
395 | : dkim_exim_expand_defaults(what) | |
396 | : dkim_exim_expand_defaults(what); | |
397 | ||
398 | case DKIM_KEY_NOTES: | |
399 | return dkim_cur_sig->pubkey | |
400 | ? dkim_cur_sig->pubkey->notes | |
401 | ? US dkim_cur_sig->pubkey->notes | |
402 | : dkim_exim_expand_defaults(what) | |
403 | : dkim_exim_expand_defaults(what); | |
404 | ||
405 | case DKIM_KEY_TESTING: | |
406 | return dkim_cur_sig->pubkey | |
407 | ? dkim_cur_sig->pubkey->testing | |
408 | ? US"1" | |
409 | : dkim_exim_expand_defaults(what) | |
410 | : dkim_exim_expand_defaults(what); | |
411 | ||
412 | case DKIM_NOSUBDOMAINS: | |
413 | return dkim_cur_sig->pubkey | |
414 | ? dkim_cur_sig->pubkey->no_subdomaining | |
415 | ? US"1" | |
416 | : dkim_exim_expand_defaults(what) | |
417 | : dkim_exim_expand_defaults(what); | |
418 | ||
419 | case DKIM_VERIFY_STATUS: | |
420 | switch (dkim_cur_sig->verify_status) | |
421 | { | |
422 | case PDKIM_VERIFY_INVALID: return US"invalid"; | |
423 | case PDKIM_VERIFY_FAIL: return US"fail"; | |
424 | case PDKIM_VERIFY_PASS: return US"pass"; | |
425 | case PDKIM_VERIFY_NONE: | |
426 | default: return US"none"; | |
80a47a2c | 427 | } |
80a47a2c | 428 | |
1cfe5c1c JH |
429 | case DKIM_VERIFY_REASON: |
430 | switch (dkim_cur_sig->verify_ext_status) | |
431 | { | |
432 | case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: | |
433 | return US"pubkey_unavailable"; | |
df3def24 JH |
434 | case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD:return US"pubkey_dns_syntax"; |
435 | case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: return US"pubkey_der_syntax"; | |
1cfe5c1c JH |
436 | case PDKIM_VERIFY_FAIL_BODY: return US"bodyhash_mismatch"; |
437 | case PDKIM_VERIFY_FAIL_MESSAGE: return US"signature_incorrect"; | |
438 | } | |
80a47a2c | 439 | |
1cfe5c1c JH |
440 | default: |
441 | return US""; | |
80a47a2c TK |
442 | } |
443 | } | |
444 | ||
445 | ||
42055a33 JH |
446 | /* Generate signatures for the given file, returning a string. |
447 | If a prefix is given, prepend it to the file for the calculations. | |
448 | */ | |
449 | ||
94e1f16d | 450 | gstring * |
42055a33 JH |
451 | dkim_exim_sign(int fd, off_t off, uschar * prefix, |
452 | struct ob_dkim * dkim, const uschar ** errstr) | |
55414b25 | 453 | { |
e983e85a | 454 | const uschar * dkim_domain; |
1cfe5c1c | 455 | int sep = 0; |
94e1f16d | 456 | gstring * seen_doms = NULL; |
9e70917d JH |
457 | pdkim_ctx ctx; |
458 | pdkim_signature * sig; | |
94e1f16d | 459 | gstring * sigbuf; |
1cfe5c1c JH |
460 | int pdkim_rc; |
461 | int sread; | |
ef698bf6 | 462 | uschar buf[4096]; |
1cfe5c1c JH |
463 | int save_errno = 0; |
464 | int old_pool = store_pool; | |
7c6ec81b | 465 | uschar * errwhen; |
1cfe5c1c JH |
466 | |
467 | store_pool = POOL_MAIN; | |
468 | ||
9e70917d JH |
469 | pdkim_init_context(&ctx, dkim->dot_stuffed, &dkim_exim_query_dns_txt); |
470 | ||
e983e85a | 471 | if (!(dkim_domain = expand_cstring(dkim->dkim_domain))) |
1cfe5c1c | 472 | /* expansion error, do not send message. */ |
7c6ec81b | 473 | { errwhen = US"dkim_domain"; goto expand_bad; } |
1cfe5c1c JH |
474 | |
475 | /* Set $dkim_domain expansion variable to each unique domain in list. */ | |
476 | ||
42055a33 | 477 | while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, NULL, 0))) |
1cfe5c1c | 478 | { |
9e70917d JH |
479 | const uschar * dkim_sel; |
480 | int sel_sep = 0; | |
481 | ||
42055a33 | 482 | if (dkim_signing_domain[0] == '\0') |
1cfe5c1c JH |
483 | continue; |
484 | ||
485 | /* Only sign once for each domain, no matter how often it | |
486 | appears in the expanded list. */ | |
487 | ||
9e70917d JH |
488 | if (match_isinlist(dkim_signing_domain, CUSS &seen_doms, |
489 | 0, NULL, NULL, MCL_STRING, TRUE, NULL) == OK) | |
490 | continue; | |
1cfe5c1c | 491 | |
94e1f16d | 492 | seen_doms = string_append_listele(seen_doms, ':', dkim_signing_domain); |
1cfe5c1c | 493 | |
9e70917d JH |
494 | /* Set $dkim_selector expansion variable to each selector in list, |
495 | for this domain. */ | |
1cfe5c1c | 496 | |
9e70917d | 497 | if (!(dkim_sel = expand_string(dkim->dkim_selector))) |
e983e85a | 498 | if (!(dkim_signing_selector = expand_string(dkim->dkim_selector))) |
7c6ec81b | 499 | { errwhen = US"dkim_selector"; goto expand_bad; } |
1cfe5c1c | 500 | |
9e70917d JH |
501 | while ((dkim_signing_selector = string_nextinlist(&dkim_sel, &sel_sep, |
502 | NULL, 0))) | |
1cfe5c1c | 503 | { |
9e70917d JH |
504 | uschar * dkim_canon_expanded; |
505 | int pdkim_canon; | |
506 | uschar * dkim_sign_headers_expanded = NULL; | |
507 | uschar * dkim_private_key_expanded; | |
508 | uschar * dkim_hash_expanded; | |
7c6ec81b | 509 | uschar * dkim_identity_expanded = NULL; |
80a47a2c | 510 | |
9e70917d | 511 | /* Get canonicalization to use */ |
1cfe5c1c | 512 | |
9e70917d JH |
513 | dkim_canon_expanded = dkim->dkim_canon |
514 | ? expand_string(dkim->dkim_canon) : US"relaxed"; | |
7c6ec81b JH |
515 | if (!dkim_canon_expanded) /* expansion error, do not send message. */ |
516 | { errwhen = US"dkim_canon"; goto expand_bad; } | |
1cfe5c1c | 517 | |
9e70917d JH |
518 | if (Ustrcmp(dkim_canon_expanded, "relaxed") == 0) |
519 | pdkim_canon = PDKIM_CANON_RELAXED; | |
520 | else if (Ustrcmp(dkim_canon_expanded, "simple") == 0) | |
521 | pdkim_canon = PDKIM_CANON_SIMPLE; | |
522 | else | |
523 | { | |
524 | log_write(0, LOG_MAIN, | |
525 | "DKIM: unknown canonicalization method '%s', defaulting to 'relaxed'.\n", | |
526 | dkim_canon_expanded); | |
527 | pdkim_canon = PDKIM_CANON_RELAXED; | |
528 | } | |
1cfe5c1c | 529 | |
7c6ec81b JH |
530 | if ( dkim->dkim_sign_headers |
531 | && !(dkim_sign_headers_expanded = expand_string(dkim->dkim_sign_headers))) | |
532 | { errwhen = US"dkim_sign_header"; goto expand_bad; } | |
533 | /* else pass NULL, which means default header list */ | |
1cfe5c1c | 534 | |
9e70917d | 535 | /* Get private key to use. */ |
e983e85a | 536 | |
9e70917d | 537 | if (!(dkim_private_key_expanded = expand_string(dkim->dkim_private_key))) |
7c6ec81b | 538 | { errwhen = US"dkim_private_key"; goto expand_bad; } |
80a47a2c | 539 | |
9e70917d JH |
540 | if ( Ustrlen(dkim_private_key_expanded) == 0 |
541 | || Ustrcmp(dkim_private_key_expanded, "0") == 0 | |
542 | || Ustrcmp(dkim_private_key_expanded, "false") == 0 | |
543 | ) | |
544 | continue; /* don't sign, but no error */ | |
545 | ||
546 | if (dkim_private_key_expanded[0] == '/') | |
1cfe5c1c | 547 | { |
9e70917d JH |
548 | int privkey_fd, off = 0, len; |
549 | ||
550 | /* Looks like a filename, load the private key. */ | |
551 | ||
552 | memset(big_buffer, 0, big_buffer_size); | |
553 | ||
554 | if ((privkey_fd = open(CS dkim_private_key_expanded, O_RDONLY)) < 0) | |
59d98039 | 555 | { |
9e70917d JH |
556 | log_write(0, LOG_MAIN | LOG_PANIC, "unable to open " |
557 | "private key file for reading: %s", | |
59d98039 JH |
558 | dkim_private_key_expanded); |
559 | goto bad; | |
560 | } | |
9e70917d JH |
561 | |
562 | do | |
563 | { | |
564 | if ((len = read(privkey_fd, big_buffer + off, big_buffer_size - 2 - off)) < 0) | |
565 | { | |
566 | (void) close(privkey_fd); | |
567 | log_write(0, LOG_MAIN|LOG_PANIC, "unable to read private key file: %s", | |
568 | dkim_private_key_expanded); | |
569 | goto bad; | |
570 | } | |
571 | off += len; | |
572 | } | |
573 | while (len > 0); | |
574 | ||
575 | (void) close(privkey_fd); | |
576 | big_buffer[off] = '\0'; | |
577 | dkim_private_key_expanded = big_buffer; | |
1ac6b2e7 | 578 | } |
80a47a2c | 579 | |
9e70917d | 580 | if (!(dkim_hash_expanded = expand_string(dkim->dkim_hash))) |
7c6ec81b JH |
581 | { errwhen = US"dkim_hash"; goto expand_bad; } |
582 | ||
583 | if (dkim->dkim_identity) | |
584 | if (!(dkim_identity_expanded = expand_string(dkim->dkim_identity))) | |
585 | { errwhen = US"dkim_identity"; goto expand_bad; } | |
586 | else if (!*dkim_identity_expanded) | |
587 | dkim_identity_expanded = NULL; | |
1cfe5c1c | 588 | |
9e70917d JH |
589 | /*XXX so we currently nail signing to RSA + this hash. |
590 | Need to extract algo from privkey and check for disallowed combos. */ | |
d73e45df | 591 | |
9e70917d JH |
592 | if (!(sig = pdkim_init_sign(&ctx, dkim_signing_domain, |
593 | dkim_signing_selector, | |
594 | dkim_private_key_expanded, | |
595 | dkim_hash_expanded, | |
596 | errstr | |
597 | ))) | |
598 | goto bad; | |
599 | dkim_private_key_expanded[0] = '\0'; | |
600 | ||
601 | pdkim_set_optional(sig, | |
602 | CS dkim_sign_headers_expanded, | |
7c6ec81b | 603 | dkim_identity_expanded, |
9e70917d JH |
604 | pdkim_canon, |
605 | pdkim_canon, -1, 0, 0); | |
606 | ||
607 | if (!ctx.sig) /* link sig to context chain */ | |
608 | ctx.sig = sig; | |
609 | else | |
610 | { | |
611 | pdkim_signature * n = ctx.sig; | |
612 | while (n->next) n = n->next; | |
613 | n->next = sig; | |
614 | } | |
80a47a2c | 615 | } |
9e70917d | 616 | } |
80a47a2c | 617 | |
9e70917d JH |
618 | if (prefix) |
619 | pdkim_feed(&ctx, prefix, Ustrlen(prefix)); | |
80a47a2c | 620 | |
9e70917d JH |
621 | if (lseek(fd, off, SEEK_SET) < 0) |
622 | sread = -1; | |
623 | else | |
624 | while ((sread = read(fd, &buf, sizeof(buf))) > 0) | |
625 | if ((pdkim_rc = pdkim_feed(&ctx, buf, sread)) != PDKIM_OK) | |
626 | goto pk_bad; | |
80a47a2c | 627 | |
9e70917d JH |
628 | /* Handle failed read above. */ |
629 | if (sread == -1) | |
630 | { | |
631 | debug_printf("DKIM: Error reading -K file.\n"); | |
632 | save_errno = errno; | |
633 | goto bad; | |
80a47a2c | 634 | } |
a8e1eeba | 635 | |
9e70917d JH |
636 | /* Build string of headers, one per signature */ |
637 | ||
638 | if ((pdkim_rc = pdkim_feed_finish(&ctx, &sig, errstr)) != PDKIM_OK) | |
639 | goto pk_bad; | |
640 | ||
94e1f16d JH |
641 | for (sigbuf = NULL; sig; sig = sig->next) |
642 | sigbuf = string_append(sigbuf, 2, US sig->signature_header, US"\r\n"); | |
9e70917d | 643 | |
94e1f16d | 644 | (void) string_from_gstring(sigbuf); |
1cfe5c1c JH |
645 | |
646 | CLEANUP: | |
f7302073 JH |
647 | store_pool = old_pool; |
648 | errno = save_errno; | |
9e70917d | 649 | return sigbuf; |
f7302073 JH |
650 | |
651 | pk_bad: | |
652 | log_write(0, LOG_MAIN|LOG_PANIC, | |
653 | "DKIM: signing failed: %.100s", pdkim_errstr(pdkim_rc)); | |
654 | bad: | |
9e70917d | 655 | sigbuf = NULL; |
f7302073 | 656 | goto CLEANUP; |
7c6ec81b JH |
657 | |
658 | expand_bad: | |
659 | log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand %s: %s", | |
660 | errwhen, expand_string_message); | |
661 | goto bad; | |
93f2d376 | 662 | } |
80a47a2c TK |
663 | |
664 | #endif |