Commit | Line | Data |
---|---|---|
80a47a2c TK |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
d4e5e70b | 5 | /* Copyright (c) University of Cambridge, 1995 - 2017 */ |
80a47a2c TK |
6 | /* See the file NOTICE for conditions of use and distribution. */ |
7 | ||
8 | /* Code for DKIM support. Other DKIM relevant code is in | |
9 | receive.c, transport.c and transports/smtp.c */ | |
10 | ||
11 | #include "exim.h" | |
12 | ||
13 | #ifndef DISABLE_DKIM | |
14 | ||
970424a5 JH |
15 | # include "pdkim/pdkim.h" |
16 | ||
17 | # ifdef MACRO_PREDEF | |
5f69a529 | 18 | # include "macro_predef.h" |
970424a5 JH |
19 | |
20 | void | |
a2701501 | 21 | params_dkim(void) |
970424a5 JH |
22 | { |
23 | builtin_macro_create_var(US"_DKIM_SIGN_HEADERS", US PDKIM_DEFAULT_SIGN_HEADERS); | |
24 | } | |
25 | # else /*!MACRO_PREDEF*/ | |
26 | ||
27 | ||
28 | ||
80a47a2c | 29 | |
ca9cb170 | 30 | int dkim_verify_oldpool; |
1cfe5c1c | 31 | pdkim_ctx *dkim_verify_ctx = NULL; |
80a47a2c | 32 | pdkim_signature *dkim_signatures = NULL; |
1cfe5c1c | 33 | pdkim_signature *dkim_cur_sig = NULL; |
b9df1829 | 34 | static const uschar * dkim_collect_error = NULL; |
80a47a2c | 35 | |
d73e45df JH |
36 | |
37 | ||
38 | /*XXX the caller only uses the first record if we return multiple. | |
39 | Could we hand back an allocated string? | |
40 | */ | |
41 | ||
1cfe5c1c JH |
42 | static int |
43 | dkim_exim_query_dns_txt(char *name, char *answer) | |
44 | { | |
45 | dns_answer dnsa; | |
46 | dns_scan dnss; | |
47 | dns_record *rr; | |
80a47a2c | 48 | |
1cfe5c1c JH |
49 | lookup_dnssec_authenticated = NULL; |
50 | if (dns_lookup(&dnsa, US name, T_TXT, NULL) != DNS_SUCCEED) | |
f7302073 | 51 | return PDKIM_FAIL; /*XXX better error detail? logging? */ |
80a47a2c | 52 | |
1cfe5c1c | 53 | /* Search for TXT record */ |
80a47a2c | 54 | |
1cfe5c1c JH |
55 | for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS); |
56 | rr; | |
57 | rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) | |
58 | if (rr->type == T_TXT) | |
59 | { | |
80a47a2c TK |
60 | int rr_offset = 0; |
61 | int answer_offset = 0; | |
1cfe5c1c JH |
62 | |
63 | /* Copy record content to the answer buffer */ | |
64 | ||
65 | while (rr_offset < rr->size) | |
66 | { | |
67 | uschar len = rr->data[rr_offset++]; | |
68 | snprintf(answer + answer_offset, | |
69 | PDKIM_DNS_TXT_MAX_RECLEN - answer_offset, | |
5903c6ff | 70 | "%.*s", (int)len, CS (rr->data + rr_offset)); |
1cfe5c1c JH |
71 | rr_offset += len; |
72 | answer_offset += len; | |
73 | if (answer_offset >= PDKIM_DNS_TXT_MAX_RECLEN) | |
f7302073 | 74 | return PDKIM_FAIL; /*XXX better error detail? logging? */ |
4263f395 | 75 | } |
1cfe5c1c | 76 | return PDKIM_OK; |
80a47a2c | 77 | } |
80a47a2c | 78 | |
f7302073 | 79 | return PDKIM_FAIL; /*XXX better error detail? logging? */ |
80a47a2c TK |
80 | } |
81 | ||
82 | ||
2592e6c0 JH |
83 | void |
84 | dkim_exim_init(void) | |
85 | { | |
86 | pdkim_init(); | |
87 | } | |
88 | ||
89 | ||
ca9cb170 | 90 | |
1cfe5c1c | 91 | void |
e983e85a | 92 | dkim_exim_verify_init(BOOL dot_stuffing) |
1cfe5c1c | 93 | { |
ca9cb170 JH |
94 | /* There is a store-reset between header & body reception |
95 | so cannot use the main pool. Any allocs done by Exim | |
96 | memory-handling must use the perm pool. */ | |
97 | ||
98 | dkim_verify_oldpool = store_pool; | |
99 | store_pool = POOL_PERM; | |
100 | ||
1cfe5c1c | 101 | /* Free previous context if there is one */ |
80a47a2c | 102 | |
1cfe5c1c JH |
103 | if (dkim_verify_ctx) |
104 | pdkim_free_ctx(dkim_verify_ctx); | |
80a47a2c | 105 | |
1cfe5c1c | 106 | /* Create new context */ |
80a47a2c | 107 | |
e983e85a | 108 | dkim_verify_ctx = pdkim_init_verify(&dkim_exim_query_dns_txt, dot_stuffing); |
3b957582 | 109 | dkim_collect_input = !!dkim_verify_ctx; |
b9df1829 | 110 | dkim_collect_error = NULL; |
ca9cb170 | 111 | |
584e96c6 JH |
112 | /* Start feed up with any cached data */ |
113 | receive_get_cache(); | |
114 | ||
ca9cb170 | 115 | store_pool = dkim_verify_oldpool; |
80a47a2c TK |
116 | } |
117 | ||
118 | ||
1cfe5c1c JH |
119 | void |
120 | dkim_exim_verify_feed(uschar * data, int len) | |
121 | { | |
f7302073 JH |
122 | int rc; |
123 | ||
ca9cb170 | 124 | store_pool = POOL_PERM; |
1cfe5c1c | 125 | if ( dkim_collect_input |
ef698bf6 | 126 | && (rc = pdkim_feed(dkim_verify_ctx, data, len)) != PDKIM_OK) |
f7302073 | 127 | { |
b9df1829 | 128 | dkim_collect_error = pdkim_errstr(rc); |
f7302073 | 129 | log_write(0, LOG_MAIN, |
b9df1829 | 130 | "DKIM: validation error: %.100s", dkim_collect_error); |
1cfe5c1c | 131 | dkim_collect_input = FALSE; |
f7302073 | 132 | } |
ca9cb170 | 133 | store_pool = dkim_verify_oldpool; |
80a47a2c TK |
134 | } |
135 | ||
136 | ||
1cfe5c1c JH |
137 | void |
138 | dkim_exim_verify_finish(void) | |
139 | { | |
41468ba1 | 140 | pdkim_signature * sig = NULL; |
bb07bcd3 | 141 | int rc; |
acec9514 | 142 | gstring * g = NULL; |
b9df1829 | 143 | const uschar * errstr; |
1cfe5c1c | 144 | |
ca9cb170 JH |
145 | store_pool = POOL_PERM; |
146 | ||
1cfe5c1c JH |
147 | /* Delete eventual previous signature chain */ |
148 | ||
41468ba1 | 149 | dkim_signers = NULL; |
1cfe5c1c JH |
150 | dkim_signatures = NULL; |
151 | ||
bd8fbe36 | 152 | if (dkim_collect_error) |
1cfe5c1c JH |
153 | { |
154 | log_write(0, LOG_MAIN, | |
b9df1829 JH |
155 | "DKIM: Error during validation, disabling signature verification: %.100s", |
156 | dkim_collect_error); | |
1cfe5c1c | 157 | dkim_disable_verify = TRUE; |
ca9cb170 | 158 | goto out; |
1cfe5c1c | 159 | } |
80a47a2c | 160 | |
1cfe5c1c | 161 | dkim_collect_input = FALSE; |
80a47a2c | 162 | |
1cfe5c1c | 163 | /* Finish DKIM operation and fetch link to signatures chain */ |
80a47a2c | 164 | |
b9df1829 JH |
165 | rc = pdkim_feed_finish(dkim_verify_ctx, &dkim_signatures, &errstr); |
166 | if (rc != PDKIM_OK) | |
f7302073 | 167 | { |
b9df1829 JH |
168 | log_write(0, LOG_MAIN, "DKIM: validation error: %.100s%s%s", pdkim_errstr(rc), |
169 | errstr ? ": " : "", errstr ? errstr : US""); | |
ca9cb170 | 170 | goto out; |
f7302073 | 171 | } |
1cfe5c1c JH |
172 | |
173 | for (sig = dkim_signatures; sig; sig = sig->next) | |
174 | { | |
acec9514 JH |
175 | uschar * s; |
176 | gstring * logmsg; | |
1cfe5c1c JH |
177 | |
178 | /* Log a line for each signature */ | |
179 | ||
41468ba1 | 180 | if (!(s = sig->domain)) s = US"<UNSET>"; |
acec9514 | 181 | logmsg = string_append(NULL, 2, "d=", s); |
41468ba1 | 182 | if (!(s = sig->selector)) s = US"<UNSET>"; |
acec9514 JH |
183 | logmsg = string_append(logmsg, 2, " s=", s); |
184 | logmsg = string_append(logmsg, 7, | |
41468ba1 JH |
185 | " c=", sig->canon_headers == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", |
186 | "/", sig->canon_body == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", | |
d73e45df | 187 | " a=", dkim_sig_to_a_tag(sig), |
bb07bcd3 | 188 | string_sprintf(" b=" SIZE_T_FMT, |
41468ba1 | 189 | (int)sig->sighash.len > -1 ? sig->sighash.len * 8 : 0)); |
acec9514 JH |
190 | if ((s= sig->identity)) logmsg = string_append(logmsg, 2, " i=", s); |
191 | if (sig->created > 0) logmsg = string_cat(logmsg, | |
41468ba1 | 192 | string_sprintf(" t=%lu", sig->created)); |
acec9514 | 193 | if (sig->expires > 0) logmsg = string_cat(logmsg, |
41468ba1 | 194 | string_sprintf(" x=%lu", sig->expires)); |
acec9514 | 195 | if (sig->bodylength > -1) logmsg = string_cat(logmsg, |
41468ba1 | 196 | string_sprintf(" l=%lu", sig->bodylength)); |
1cfe5c1c JH |
197 | |
198 | switch (sig->verify_status) | |
199 | { | |
200 | case PDKIM_VERIFY_NONE: | |
acec9514 | 201 | logmsg = string_cat(logmsg, " [not verified]"); |
80a47a2c | 202 | break; |
1cfe5c1c JH |
203 | |
204 | case PDKIM_VERIFY_INVALID: | |
acec9514 | 205 | logmsg = string_cat(logmsg, " [invalid - "); |
1cfe5c1c JH |
206 | switch (sig->verify_ext_status) |
207 | { | |
208 | case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: | |
acec9514 | 209 | logmsg = string_cat(logmsg, |
1cfe5c1c JH |
210 | "public key record (currently?) unavailable]"); |
211 | break; | |
212 | ||
213 | case PDKIM_VERIFY_INVALID_BUFFER_SIZE: | |
acec9514 | 214 | logmsg = string_cat(logmsg, "overlong public key record]"); |
1cfe5c1c JH |
215 | break; |
216 | ||
df3def24 JH |
217 | case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: |
218 | case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: | |
acec9514 | 219 | logmsg = string_cat(logmsg, "syntax error in public key record]"); |
1cfe5c1c | 220 | break; |
07eeb4df | 221 | |
222 | case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: | |
acec9514 | 223 | logmsg = string_cat(logmsg, "signature tag missing or invalid]"); |
07eeb4df | 224 | break; |
225 | ||
226 | case PDKIM_VERIFY_INVALID_DKIM_VERSION: | |
acec9514 | 227 | logmsg = string_cat(logmsg, "unsupported DKIM version]"); |
07eeb4df | 228 | break; |
1cfe5c1c JH |
229 | |
230 | default: | |
acec9514 | 231 | logmsg = string_cat(logmsg, "unspecified problem]"); |
1cfe5c1c | 232 | } |
80a47a2c | 233 | break; |
1cfe5c1c JH |
234 | |
235 | case PDKIM_VERIFY_FAIL: | |
236 | logmsg = | |
acec9514 | 237 | string_cat(logmsg, " [verification failed - "); |
1cfe5c1c JH |
238 | switch (sig->verify_ext_status) |
239 | { | |
240 | case PDKIM_VERIFY_FAIL_BODY: | |
acec9514 | 241 | logmsg = string_cat(logmsg, |
1cfe5c1c JH |
242 | "body hash mismatch (body probably modified in transit)]"); |
243 | break; | |
244 | ||
245 | case PDKIM_VERIFY_FAIL_MESSAGE: | |
acec9514 | 246 | logmsg = string_cat(logmsg, |
1cfe5c1c JH |
247 | "signature did not verify (headers probably modified in transit)]"); |
248 | break; | |
249 | ||
250 | default: | |
acec9514 | 251 | logmsg = string_cat(logmsg, "unspecified reason]"); |
1cfe5c1c | 252 | } |
80a47a2c | 253 | break; |
1cfe5c1c JH |
254 | |
255 | case PDKIM_VERIFY_PASS: | |
acec9514 | 256 | logmsg = string_cat(logmsg, " [verification succeeded]"); |
80a47a2c TK |
257 | break; |
258 | } | |
259 | ||
acec9514 | 260 | log_write(0, LOG_MAIN, "DKIM: %s", string_from_gstring(logmsg)); |
80a47a2c | 261 | |
1cfe5c1c JH |
262 | /* Build a colon-separated list of signing domains (and identities, if present) in dkim_signers */ |
263 | ||
41468ba1 | 264 | if (sig->domain) |
acec9514 | 265 | g = string_append_listele(g, ':', sig->domain); |
1cfe5c1c JH |
266 | |
267 | if (sig->identity) | |
acec9514 | 268 | g = string_append_listele(g, ':', sig->identity); |
80a47a2c | 269 | |
1cfe5c1c | 270 | /* Process next signature */ |
80a47a2c TK |
271 | } |
272 | ||
acec9514 JH |
273 | if (g) dkim_signers = g->s; |
274 | ||
ca9cb170 JH |
275 | out: |
276 | store_pool = dkim_verify_oldpool; | |
80a47a2c TK |
277 | } |
278 | ||
279 | ||
1cfe5c1c JH |
280 | void |
281 | dkim_exim_acl_setup(uschar * id) | |
282 | { | |
283 | pdkim_signature * sig; | |
284 | uschar * cmp_val; | |
285 | ||
1cfe5c1c JH |
286 | dkim_cur_sig = NULL; |
287 | dkim_cur_signer = id; | |
288 | ||
289 | if (dkim_disable_verify || !id || !dkim_verify_ctx) | |
290 | return; | |
291 | ||
292 | /* Find signature to run ACL on */ | |
293 | ||
294 | for (sig = dkim_signatures; sig; sig = sig->next) | |
295 | if ( (cmp_val = Ustrchr(id, '@') != NULL ? US sig->identity : US sig->domain) | |
296 | && strcmpic(cmp_val, id) == 0 | |
297 | ) | |
298 | { | |
299 | dkim_cur_sig = sig; | |
300 | ||
301 | /* The "dkim_domain" and "dkim_selector" expansion variables have | |
302 | related globals, since they are used in the signing code too. | |
303 | Instead of inventing separate names for verification, we set | |
304 | them here. This is easy since a domain and selector is guaranteed | |
305 | to be in a signature. The other dkim_* expansion items are | |
306 | dynamically fetched from dkim_cur_sig at expansion time (see | |
307 | function below). */ | |
308 | ||
309 | dkim_signing_domain = US sig->domain; | |
310 | dkim_signing_selector = US sig->selector; | |
dcd03763 | 311 | dkim_key_length = sig->sighash.len * 8; |
1cfe5c1c | 312 | return; |
80a47a2c | 313 | } |
80a47a2c TK |
314 | } |
315 | ||
316 | ||
1cfe5c1c JH |
317 | static uschar * |
318 | dkim_exim_expand_defaults(int what) | |
319 | { | |
320 | switch (what) | |
321 | { | |
322 | case DKIM_ALGO: return US""; | |
323 | case DKIM_BODYLENGTH: return US"9999999999999"; | |
324 | case DKIM_CANON_BODY: return US""; | |
325 | case DKIM_CANON_HEADERS: return US""; | |
326 | case DKIM_COPIEDHEADERS: return US""; | |
327 | case DKIM_CREATED: return US"0"; | |
328 | case DKIM_EXPIRES: return US"9999999999999"; | |
329 | case DKIM_HEADERNAMES: return US""; | |
330 | case DKIM_IDENTITY: return US""; | |
331 | case DKIM_KEY_GRANULARITY: return US"*"; | |
332 | case DKIM_KEY_SRVTYPE: return US"*"; | |
333 | case DKIM_KEY_NOTES: return US""; | |
334 | case DKIM_KEY_TESTING: return US"0"; | |
335 | case DKIM_NOSUBDOMAINS: return US"0"; | |
336 | case DKIM_VERIFY_STATUS: return US"none"; | |
337 | case DKIM_VERIFY_REASON: return US""; | |
338 | default: return US""; | |
339 | } | |
340 | } | |
80a47a2c | 341 | |
80a47a2c | 342 | |
1cfe5c1c JH |
343 | uschar * |
344 | dkim_exim_expand_query(int what) | |
345 | { | |
346 | if (!dkim_verify_ctx || dkim_disable_verify || !dkim_cur_sig) | |
347 | return dkim_exim_expand_defaults(what); | |
348 | ||
349 | switch (what) | |
350 | { | |
351 | case DKIM_ALGO: | |
d73e45df | 352 | return dkim_sig_to_a_tag(dkim_cur_sig); |
1cfe5c1c JH |
353 | |
354 | case DKIM_BODYLENGTH: | |
355 | return dkim_cur_sig->bodylength >= 0 | |
bb07bcd3 | 356 | ? string_sprintf("%ld", dkim_cur_sig->bodylength) |
1cfe5c1c JH |
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 | |
bb07bcd3 | 381 | ? string_sprintf("%lu", dkim_cur_sig->created) |
1cfe5c1c JH |
382 | : dkim_exim_expand_defaults(what); |
383 | ||
384 | case DKIM_EXPIRES: | |
385 | return dkim_cur_sig->expires > 0 | |
bb07bcd3 | 386 | ? string_sprintf("%lu", dkim_cur_sig->expires) |
1cfe5c1c JH |
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 | ||
42055a33 JH |
459 | /* Generate signatures for the given file, returning a string. |
460 | If a prefix is given, prepend it to the file for the calculations. | |
461 | */ | |
462 | ||
acec9514 | 463 | gstring * |
42055a33 JH |
464 | dkim_exim_sign(int fd, off_t off, uschar * prefix, |
465 | struct ob_dkim * dkim, const uschar ** errstr) | |
55414b25 | 466 | { |
e983e85a | 467 | const uschar * dkim_domain; |
1cfe5c1c | 468 | int sep = 0; |
acec9514 | 469 | gstring * seen_doms = NULL; |
9e70917d JH |
470 | pdkim_ctx ctx; |
471 | pdkim_signature * sig; | |
acec9514 | 472 | gstring * sigbuf; |
1cfe5c1c JH |
473 | int pdkim_rc; |
474 | int sread; | |
ef698bf6 | 475 | uschar buf[4096]; |
1cfe5c1c JH |
476 | int save_errno = 0; |
477 | int old_pool = store_pool; | |
7c6ec81b | 478 | uschar * errwhen; |
1cfe5c1c JH |
479 | |
480 | store_pool = POOL_MAIN; | |
481 | ||
9e70917d JH |
482 | pdkim_init_context(&ctx, dkim->dot_stuffed, &dkim_exim_query_dns_txt); |
483 | ||
e983e85a | 484 | if (!(dkim_domain = expand_cstring(dkim->dkim_domain))) |
1cfe5c1c | 485 | /* expansion error, do not send message. */ |
7c6ec81b | 486 | { errwhen = US"dkim_domain"; goto expand_bad; } |
1cfe5c1c JH |
487 | |
488 | /* Set $dkim_domain expansion variable to each unique domain in list. */ | |
489 | ||
42055a33 | 490 | while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, NULL, 0))) |
1cfe5c1c | 491 | { |
9e70917d JH |
492 | const uschar * dkim_sel; |
493 | int sel_sep = 0; | |
494 | ||
42055a33 | 495 | if (dkim_signing_domain[0] == '\0') |
1cfe5c1c JH |
496 | continue; |
497 | ||
498 | /* Only sign once for each domain, no matter how often it | |
499 | appears in the expanded list. */ | |
500 | ||
9e70917d JH |
501 | if (match_isinlist(dkim_signing_domain, CUSS &seen_doms, |
502 | 0, NULL, NULL, MCL_STRING, TRUE, NULL) == OK) | |
503 | continue; | |
1cfe5c1c | 504 | |
acec9514 | 505 | seen_doms = string_append_listele(seen_doms, ':', dkim_signing_domain); |
1cfe5c1c | 506 | |
9e70917d JH |
507 | /* Set $dkim_selector expansion variable to each selector in list, |
508 | for this domain. */ | |
1cfe5c1c | 509 | |
9e70917d | 510 | if (!(dkim_sel = expand_string(dkim->dkim_selector))) |
e983e85a | 511 | if (!(dkim_signing_selector = expand_string(dkim->dkim_selector))) |
7c6ec81b | 512 | { errwhen = US"dkim_selector"; goto expand_bad; } |
1cfe5c1c | 513 | |
9e70917d JH |
514 | while ((dkim_signing_selector = string_nextinlist(&dkim_sel, &sel_sep, |
515 | NULL, 0))) | |
1cfe5c1c | 516 | { |
9e70917d JH |
517 | uschar * dkim_canon_expanded; |
518 | int pdkim_canon; | |
519 | uschar * dkim_sign_headers_expanded = NULL; | |
520 | uschar * dkim_private_key_expanded; | |
521 | uschar * dkim_hash_expanded; | |
7c6ec81b | 522 | uschar * dkim_identity_expanded = NULL; |
80a47a2c | 523 | |
9e70917d | 524 | /* Get canonicalization to use */ |
1cfe5c1c | 525 | |
9e70917d JH |
526 | dkim_canon_expanded = dkim->dkim_canon |
527 | ? expand_string(dkim->dkim_canon) : US"relaxed"; | |
7c6ec81b JH |
528 | if (!dkim_canon_expanded) /* expansion error, do not send message. */ |
529 | { errwhen = US"dkim_canon"; goto expand_bad; } | |
1cfe5c1c | 530 | |
9e70917d JH |
531 | if (Ustrcmp(dkim_canon_expanded, "relaxed") == 0) |
532 | pdkim_canon = PDKIM_CANON_RELAXED; | |
533 | else if (Ustrcmp(dkim_canon_expanded, "simple") == 0) | |
534 | pdkim_canon = PDKIM_CANON_SIMPLE; | |
535 | else | |
536 | { | |
537 | log_write(0, LOG_MAIN, | |
538 | "DKIM: unknown canonicalization method '%s', defaulting to 'relaxed'.\n", | |
539 | dkim_canon_expanded); | |
540 | pdkim_canon = PDKIM_CANON_RELAXED; | |
541 | } | |
1cfe5c1c | 542 | |
7c6ec81b JH |
543 | if ( dkim->dkim_sign_headers |
544 | && !(dkim_sign_headers_expanded = expand_string(dkim->dkim_sign_headers))) | |
545 | { errwhen = US"dkim_sign_header"; goto expand_bad; } | |
546 | /* else pass NULL, which means default header list */ | |
1cfe5c1c | 547 | |
9e70917d | 548 | /* Get private key to use. */ |
e983e85a | 549 | |
9e70917d | 550 | if (!(dkim_private_key_expanded = expand_string(dkim->dkim_private_key))) |
7c6ec81b | 551 | { errwhen = US"dkim_private_key"; goto expand_bad; } |
80a47a2c | 552 | |
9e70917d JH |
553 | if ( Ustrlen(dkim_private_key_expanded) == 0 |
554 | || Ustrcmp(dkim_private_key_expanded, "0") == 0 | |
555 | || Ustrcmp(dkim_private_key_expanded, "false") == 0 | |
556 | ) | |
557 | continue; /* don't sign, but no error */ | |
558 | ||
559 | if (dkim_private_key_expanded[0] == '/') | |
1cfe5c1c | 560 | { |
9e70917d JH |
561 | int privkey_fd, off = 0, len; |
562 | ||
563 | /* Looks like a filename, load the private key. */ | |
564 | ||
565 | memset(big_buffer, 0, big_buffer_size); | |
566 | ||
567 | if ((privkey_fd = open(CS dkim_private_key_expanded, O_RDONLY)) < 0) | |
59d98039 | 568 | { |
9e70917d JH |
569 | log_write(0, LOG_MAIN | LOG_PANIC, "unable to open " |
570 | "private key file for reading: %s", | |
59d98039 JH |
571 | dkim_private_key_expanded); |
572 | goto bad; | |
573 | } | |
9e70917d JH |
574 | |
575 | do | |
576 | { | |
577 | if ((len = read(privkey_fd, big_buffer + off, big_buffer_size - 2 - off)) < 0) | |
578 | { | |
579 | (void) close(privkey_fd); | |
580 | log_write(0, LOG_MAIN|LOG_PANIC, "unable to read private key file: %s", | |
581 | dkim_private_key_expanded); | |
582 | goto bad; | |
583 | } | |
584 | off += len; | |
585 | } | |
586 | while (len > 0); | |
587 | ||
588 | (void) close(privkey_fd); | |
589 | big_buffer[off] = '\0'; | |
590 | dkim_private_key_expanded = big_buffer; | |
1ac6b2e7 | 591 | } |
80a47a2c | 592 | |
9e70917d | 593 | if (!(dkim_hash_expanded = expand_string(dkim->dkim_hash))) |
7c6ec81b JH |
594 | { errwhen = US"dkim_hash"; goto expand_bad; } |
595 | ||
596 | if (dkim->dkim_identity) | |
597 | if (!(dkim_identity_expanded = expand_string(dkim->dkim_identity))) | |
598 | { errwhen = US"dkim_identity"; goto expand_bad; } | |
599 | else if (!*dkim_identity_expanded) | |
600 | dkim_identity_expanded = NULL; | |
1cfe5c1c | 601 | |
9e70917d JH |
602 | /*XXX so we currently nail signing to RSA + this hash. |
603 | Need to extract algo from privkey and check for disallowed combos. */ | |
d73e45df | 604 | |
9e70917d JH |
605 | if (!(sig = pdkim_init_sign(&ctx, dkim_signing_domain, |
606 | dkim_signing_selector, | |
607 | dkim_private_key_expanded, | |
608 | dkim_hash_expanded, | |
609 | errstr | |
610 | ))) | |
611 | goto bad; | |
612 | dkim_private_key_expanded[0] = '\0'; | |
613 | ||
614 | pdkim_set_optional(sig, | |
615 | CS dkim_sign_headers_expanded, | |
7c6ec81b | 616 | dkim_identity_expanded, |
9e70917d JH |
617 | pdkim_canon, |
618 | pdkim_canon, -1, 0, 0); | |
619 | ||
620 | if (!ctx.sig) /* link sig to context chain */ | |
621 | ctx.sig = sig; | |
622 | else | |
623 | { | |
624 | pdkim_signature * n = ctx.sig; | |
625 | while (n->next) n = n->next; | |
626 | n->next = sig; | |
627 | } | |
80a47a2c | 628 | } |
9e70917d | 629 | } |
80a47a2c | 630 | |
9e70917d JH |
631 | if (prefix) |
632 | pdkim_feed(&ctx, prefix, Ustrlen(prefix)); | |
80a47a2c | 633 | |
9e70917d JH |
634 | if (lseek(fd, off, SEEK_SET) < 0) |
635 | sread = -1; | |
636 | else | |
637 | while ((sread = read(fd, &buf, sizeof(buf))) > 0) | |
638 | if ((pdkim_rc = pdkim_feed(&ctx, buf, sread)) != PDKIM_OK) | |
639 | goto pk_bad; | |
80a47a2c | 640 | |
9e70917d JH |
641 | /* Handle failed read above. */ |
642 | if (sread == -1) | |
643 | { | |
644 | debug_printf("DKIM: Error reading -K file.\n"); | |
645 | save_errno = errno; | |
646 | goto bad; | |
80a47a2c | 647 | } |
a8e1eeba | 648 | |
9e70917d JH |
649 | /* Build string of headers, one per signature */ |
650 | ||
651 | if ((pdkim_rc = pdkim_feed_finish(&ctx, &sig, errstr)) != PDKIM_OK) | |
652 | goto pk_bad; | |
653 | ||
acec9514 JH |
654 | for (sigbuf = NULL; sig; sig = sig->next) |
655 | sigbuf = string_append(sigbuf, 2, US sig->signature_header, US"\r\n"); | |
9e70917d | 656 | |
acec9514 | 657 | (void) string_from_gstring(sigbuf); |
1cfe5c1c JH |
658 | |
659 | CLEANUP: | |
f7302073 JH |
660 | store_pool = old_pool; |
661 | errno = save_errno; | |
9e70917d | 662 | return sigbuf; |
f7302073 JH |
663 | |
664 | pk_bad: | |
665 | log_write(0, LOG_MAIN|LOG_PANIC, | |
666 | "DKIM: signing failed: %.100s", pdkim_errstr(pdkim_rc)); | |
667 | bad: | |
9e70917d | 668 | sigbuf = NULL; |
f7302073 | 669 | goto CLEANUP; |
7c6ec81b JH |
670 | |
671 | expand_bad: | |
672 | log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand %s: %s", | |
673 | errwhen, expand_string_message); | |
674 | goto bad; | |
93f2d376 | 675 | } |
80a47a2c | 676 | |
970424a5 JH |
677 | # endif /*!MACRO_PREDEF*/ |
678 | #endif /*!DISABLE_DKIM*/ |