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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 | ||
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. | |
d73e45df JH |
39 | */ |
40 | ||
1eedc10f JH |
41 | static uschar * |
42 | dkim_exim_query_dns_txt(char * name) | |
1cfe5c1c JH |
43 | { |
44 | dns_answer dnsa; | |
45 | dns_scan dnss; | |
46 | dns_record *rr; | |
1eedc10f | 47 | gstring * g = NULL; |
80a47a2c | 48 | |
1cfe5c1c JH |
49 | lookup_dnssec_authenticated = NULL; |
50 | if (dns_lookup(&dnsa, US name, T_TXT, NULL) != DNS_SUCCEED) | |
1eedc10f | 51 | return NULL; /*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 | 60 | int rr_offset = 0; |
1cfe5c1c JH |
61 | |
62 | /* Copy record content to the answer buffer */ | |
63 | ||
64 | while (rr_offset < rr->size) | |
65 | { | |
66 | uschar len = rr->data[rr_offset++]; | |
1eedc10f JH |
67 | |
68 | g = string_catn(g, US(rr->data + rr_offset), len); | |
69 | if (g->ptr >= PDKIM_DNS_TXT_MAX_RECLEN) | |
70 | goto bad; | |
71 | ||
1cfe5c1c | 72 | rr_offset += len; |
4263f395 | 73 | } |
dd33c4e6 HSHR |
74 | |
75 | /* check if this looks like a DKIM record */ | |
d011368a | 76 | if (Ustrncmp(g->s, "v=", 2) != 0 || strncasecmp(CS g->s, "v=dkim", 6) == 0) |
1eedc10f JH |
77 | { |
78 | store_reset(g->s + g->ptr + 1); | |
79 | return string_from_gstring(g); | |
80 | } | |
81 | ||
82 | if (g) g->ptr = 0; /* overwrite previous record */ | |
80a47a2c | 83 | } |
80a47a2c | 84 | |
1eedc10f JH |
85 | bad: |
86 | if (g) store_reset(g); | |
87 | return NULL; /*XXX better error detail? logging? */ | |
80a47a2c TK |
88 | } |
89 | ||
90 | ||
2592e6c0 JH |
91 | void |
92 | dkim_exim_init(void) | |
93 | { | |
94 | pdkim_init(); | |
95 | } | |
96 | ||
97 | ||
ca9cb170 | 98 | |
1cfe5c1c | 99 | void |
e983e85a | 100 | dkim_exim_verify_init(BOOL dot_stuffing) |
1cfe5c1c | 101 | { |
ca9cb170 JH |
102 | /* There is a store-reset between header & body reception |
103 | so cannot use the main pool. Any allocs done by Exim | |
104 | memory-handling must use the perm pool. */ | |
105 | ||
106 | dkim_verify_oldpool = store_pool; | |
107 | store_pool = POOL_PERM; | |
108 | ||
1cfe5c1c | 109 | /* Free previous context if there is one */ |
80a47a2c | 110 | |
1cfe5c1c JH |
111 | if (dkim_verify_ctx) |
112 | pdkim_free_ctx(dkim_verify_ctx); | |
80a47a2c | 113 | |
1cfe5c1c | 114 | /* Create new context */ |
80a47a2c | 115 | |
e983e85a | 116 | dkim_verify_ctx = pdkim_init_verify(&dkim_exim_query_dns_txt, dot_stuffing); |
3b957582 | 117 | dkim_collect_input = !!dkim_verify_ctx; |
b9df1829 | 118 | dkim_collect_error = NULL; |
ca9cb170 | 119 | |
584e96c6 JH |
120 | /* Start feed up with any cached data */ |
121 | receive_get_cache(); | |
122 | ||
ca9cb170 | 123 | store_pool = dkim_verify_oldpool; |
80a47a2c TK |
124 | } |
125 | ||
126 | ||
1cfe5c1c JH |
127 | void |
128 | dkim_exim_verify_feed(uschar * data, int len) | |
129 | { | |
f7302073 JH |
130 | int rc; |
131 | ||
ca9cb170 | 132 | store_pool = POOL_PERM; |
1cfe5c1c | 133 | if ( dkim_collect_input |
ef698bf6 | 134 | && (rc = pdkim_feed(dkim_verify_ctx, data, len)) != PDKIM_OK) |
f7302073 | 135 | { |
b9df1829 | 136 | dkim_collect_error = pdkim_errstr(rc); |
f7302073 | 137 | log_write(0, LOG_MAIN, |
b9df1829 | 138 | "DKIM: validation error: %.100s", dkim_collect_error); |
1cfe5c1c | 139 | dkim_collect_input = FALSE; |
f7302073 | 140 | } |
ca9cb170 | 141 | store_pool = dkim_verify_oldpool; |
80a47a2c TK |
142 | } |
143 | ||
144 | ||
a79d8834 JH |
145 | /* Log the result for the given signature */ |
146 | static void | |
147 | dkim_exim_verify_log_sig(pdkim_signature * sig) | |
1cfe5c1c | 148 | { |
cc55f420 | 149 | gstring * logmsg; |
a79d8834 JH |
150 | uschar * s; |
151 | ||
cc55f420 JH |
152 | if (!sig) return; |
153 | ||
2c47372f JH |
154 | if ( !dkim_verify_overall |
155 | && dkim_verify_status | |
156 | ? Ustrcmp(dkim_verify_status, US"pass") == 0 | |
157 | : sig->verify_status == PDKIM_VERIFY_PASS | |
158 | ) | |
159 | dkim_verify_overall = string_copy(sig->domain); | |
160 | ||
161 | if (!LOGGING(dkim_verbose)) return; | |
162 | ||
aaaa94ea | 163 | logmsg = string_catn(NULL, US"DKIM: ", 6); |
a79d8834 JH |
164 | if (!(s = sig->domain)) s = US"<UNSET>"; |
165 | logmsg = string_append(logmsg, 2, "d=", s); | |
166 | if (!(s = sig->selector)) s = US"<UNSET>"; | |
167 | logmsg = string_append(logmsg, 2, " s=", s); | |
dd33c4e6 | 168 | logmsg = string_append(logmsg, 7, |
a79d8834 JH |
169 | " c=", sig->canon_headers == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", |
170 | "/", sig->canon_body == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", | |
171 | " a=", dkim_sig_to_a_tag(sig), | |
172 | string_sprintf(" b=" SIZE_T_FMT, | |
173 | (int)sig->sighash.len > -1 ? sig->sighash.len * 8 : 0)); | |
174 | if ((s= sig->identity)) logmsg = string_append(logmsg, 2, " i=", s); | |
175 | if (sig->created > 0) logmsg = string_cat(logmsg, | |
176 | string_sprintf(" t=%lu", sig->created)); | |
177 | if (sig->expires > 0) logmsg = string_cat(logmsg, | |
178 | string_sprintf(" x=%lu", sig->expires)); | |
179 | if (sig->bodylength > -1) logmsg = string_cat(logmsg, | |
180 | string_sprintf(" l=%lu", sig->bodylength)); | |
181 | ||
182 | if ( !dkim_verify_status | |
183 | || ( dkim_verify_status == dkim_exim_expand_query(DKIM_VERIFY_STATUS) | |
184 | && dkim_verify_reason == dkim_exim_expand_query(DKIM_VERIFY_REASON) | |
185 | ) ) | |
1cfe5c1c JH |
186 | switch (sig->verify_status) |
187 | { | |
188 | case PDKIM_VERIFY_NONE: | |
aaaa94ea | 189 | logmsg = string_cat(logmsg, US" [not verified]"); |
80a47a2c | 190 | break; |
1cfe5c1c JH |
191 | |
192 | case PDKIM_VERIFY_INVALID: | |
aaaa94ea | 193 | logmsg = string_cat(logmsg, US" [invalid - "); |
1cfe5c1c JH |
194 | switch (sig->verify_ext_status) |
195 | { | |
196 | case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: | |
acec9514 | 197 | logmsg = string_cat(logmsg, |
aaaa94ea | 198 | US"public key record (currently?) unavailable]"); |
1cfe5c1c JH |
199 | break; |
200 | ||
201 | case PDKIM_VERIFY_INVALID_BUFFER_SIZE: | |
aaaa94ea | 202 | logmsg = string_cat(logmsg, US"overlong public key record]"); |
1cfe5c1c JH |
203 | break; |
204 | ||
df3def24 JH |
205 | case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: |
206 | case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: | |
aaaa94ea | 207 | logmsg = string_cat(logmsg, US"syntax error in public key record]"); |
1cfe5c1c | 208 | break; |
07eeb4df | 209 | |
a79d8834 | 210 | case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: |
aaaa94ea | 211 | logmsg = string_cat(logmsg, US"signature tag missing or invalid]"); |
a79d8834 | 212 | break; |
07eeb4df | 213 | |
a79d8834 | 214 | case PDKIM_VERIFY_INVALID_DKIM_VERSION: |
aaaa94ea | 215 | logmsg = string_cat(logmsg, US"unsupported DKIM version]"); |
a79d8834 | 216 | break; |
1cfe5c1c JH |
217 | |
218 | default: | |
aaaa94ea | 219 | logmsg = string_cat(logmsg, US"unspecified problem]"); |
1cfe5c1c | 220 | } |
80a47a2c | 221 | break; |
1cfe5c1c JH |
222 | |
223 | case PDKIM_VERIFY_FAIL: | |
aaaa94ea | 224 | logmsg = string_cat(logmsg, US" [verification failed - "); |
1cfe5c1c JH |
225 | switch (sig->verify_ext_status) |
226 | { | |
227 | case PDKIM_VERIFY_FAIL_BODY: | |
acec9514 | 228 | logmsg = string_cat(logmsg, |
aaaa94ea | 229 | US"body hash mismatch (body probably modified in transit)]"); |
1cfe5c1c JH |
230 | break; |
231 | ||
232 | case PDKIM_VERIFY_FAIL_MESSAGE: | |
acec9514 | 233 | logmsg = string_cat(logmsg, |
aaaa94ea JH |
234 | US"signature did not verify " |
235 | "(headers probably modified in transit)]"); | |
1cfe5c1c JH |
236 | break; |
237 | ||
238 | default: | |
aaaa94ea | 239 | logmsg = string_cat(logmsg, US"unspecified reason]"); |
1cfe5c1c | 240 | } |
80a47a2c | 241 | break; |
1cfe5c1c JH |
242 | |
243 | case PDKIM_VERIFY_PASS: | |
aaaa94ea | 244 | logmsg = string_cat(logmsg, US" [verification succeeded]"); |
80a47a2c TK |
245 | break; |
246 | } | |
a79d8834 JH |
247 | else |
248 | logmsg = string_append(logmsg, 5, | |
249 | US" [", dkim_verify_status, US" - ", dkim_verify_reason, US"]"); | |
250 | ||
aaaa94ea | 251 | log_write(0, LOG_MAIN, "%s", string_from_gstring(logmsg)); |
a79d8834 JH |
252 | return; |
253 | } | |
254 | ||
80a47a2c | 255 | |
a79d8834 JH |
256 | /* Log a line for each signature */ |
257 | void | |
258 | dkim_exim_verify_log_all(void) | |
259 | { | |
260 | pdkim_signature * sig; | |
261 | for (sig = dkim_signatures; sig; sig = sig->next) dkim_exim_verify_log_sig(sig); | |
262 | } | |
1cfe5c1c | 263 | |
80a47a2c | 264 | |
a79d8834 JH |
265 | void |
266 | dkim_exim_verify_finish(void) | |
267 | { | |
268 | pdkim_signature * sig; | |
269 | int rc; | |
270 | gstring * g = NULL; | |
286b9d5f | 271 | const uschar * errstr = NULL; |
a79d8834 JH |
272 | |
273 | store_pool = POOL_PERM; | |
274 | ||
275 | /* Delete eventual previous signature chain */ | |
276 | ||
277 | dkim_signers = NULL; | |
278 | dkim_signatures = NULL; | |
279 | ||
280 | if (dkim_collect_error) | |
281 | { | |
282 | log_write(0, LOG_MAIN, | |
283 | "DKIM: Error during validation, disabling signature verification: %.100s", | |
284 | dkim_collect_error); | |
285 | dkim_disable_verify = TRUE; | |
286 | goto out; | |
287 | } | |
288 | ||
289 | dkim_collect_input = FALSE; | |
290 | ||
291 | /* Finish DKIM operation and fetch link to signatures chain */ | |
292 | ||
293 | rc = pdkim_feed_finish(dkim_verify_ctx, &dkim_signatures, &errstr); | |
286b9d5f JH |
294 | if (rc != PDKIM_OK && errstr) |
295 | log_write(0, LOG_MAIN, "DKIM: validation error: %s", errstr); | |
a79d8834 JH |
296 | |
297 | /* Build a colon-separated list of signing domains (and identities, if present) in dkim_signers */ | |
298 | ||
299 | for (sig = dkim_signatures; sig; sig = sig->next) | |
300 | { | |
301 | if (sig->domain) g = string_append_listele(g, ':', sig->domain); | |
302 | if (sig->identity) g = string_append_listele(g, ':', sig->identity); | |
80a47a2c TK |
303 | } |
304 | ||
acec9514 JH |
305 | if (g) dkim_signers = g->s; |
306 | ||
ca9cb170 JH |
307 | out: |
308 | store_pool = dkim_verify_oldpool; | |
80a47a2c TK |
309 | } |
310 | ||
311 | ||
18067c75 JH |
312 | |
313 | /* Args as per dkim_exim_acl_run() below */ | |
314 | static int | |
315 | dkim_acl_call(uschar * id, gstring ** res_ptr, | |
316 | uschar ** user_msgptr, uschar ** log_msgptr) | |
317 | { | |
318 | int rc; | |
319 | DEBUG(D_receive) | |
320 | debug_printf("calling acl_smtp_dkim for dkim_cur_signer='%s'\n", id); | |
321 | ||
322 | rc = acl_check(ACL_WHERE_DKIM, NULL, acl_smtp_dkim, user_msgptr, log_msgptr); | |
323 | dkim_exim_verify_log_sig(dkim_cur_sig); | |
324 | *res_ptr = string_append_listele(*res_ptr, ':', dkim_verify_status); | |
325 | return rc; | |
326 | } | |
327 | ||
328 | ||
329 | ||
330 | /* For the given identity, run the DKIM ACL once for each matching signature. | |
331 | ||
332 | Arguments | |
333 | id Identity to look for in dkim signatures | |
334 | res_ptr ptr to growable string-list of status results, | |
335 | appended to per ACL run | |
336 | user_msgptr where to put a user error (for SMTP response) | |
337 | log_msgptr where to put a logging message (not for SMTP response) | |
338 | ||
339 | Returns: OK access is granted by an ACCEPT verb | |
340 | DISCARD access is granted by a DISCARD verb | |
341 | FAIL access is denied | |
342 | FAIL_DROP access is denied; drop the connection | |
343 | DEFER can't tell at the moment | |
344 | ERROR disaster | |
345 | */ | |
346 | ||
347 | int | |
348 | dkim_exim_acl_run(uschar * id, gstring ** res_ptr, | |
349 | uschar ** user_msgptr, uschar ** log_msgptr) | |
1cfe5c1c JH |
350 | { |
351 | pdkim_signature * sig; | |
352 | uschar * cmp_val; | |
18067c75 | 353 | int rc = -1; |
1cfe5c1c | 354 | |
cc55f420 JH |
355 | dkim_verify_status = US"none"; |
356 | dkim_verify_reason = US""; | |
1cfe5c1c JH |
357 | dkim_cur_signer = id; |
358 | ||
359 | if (dkim_disable_verify || !id || !dkim_verify_ctx) | |
18067c75 | 360 | return OK; |
1cfe5c1c | 361 | |
18067c75 | 362 | /* Find signatures to run ACL on */ |
1cfe5c1c JH |
363 | |
364 | for (sig = dkim_signatures; sig; sig = sig->next) | |
365 | if ( (cmp_val = Ustrchr(id, '@') != NULL ? US sig->identity : US sig->domain) | |
366 | && strcmpic(cmp_val, id) == 0 | |
367 | ) | |
368 | { | |
1cfe5c1c | 369 | /* The "dkim_domain" and "dkim_selector" expansion variables have |
18067c75 JH |
370 | related globals, since they are used in the signing code too. |
371 | Instead of inventing separate names for verification, we set | |
372 | them here. This is easy since a domain and selector is guaranteed | |
373 | to be in a signature. The other dkim_* expansion items are | |
374 | dynamically fetched from dkim_cur_sig at expansion time (see | |
375 | function below). */ | |
1cfe5c1c | 376 | |
18067c75 | 377 | dkim_cur_sig = sig; |
1cfe5c1c JH |
378 | dkim_signing_domain = US sig->domain; |
379 | dkim_signing_selector = US sig->selector; | |
dcd03763 | 380 | dkim_key_length = sig->sighash.len * 8; |
a79d8834 JH |
381 | |
382 | /* These two return static strings, so we can compare the addr | |
383 | later to see if the ACL overwrote them. Check that when logging */ | |
384 | ||
385 | dkim_verify_status = dkim_exim_expand_query(DKIM_VERIFY_STATUS); | |
386 | dkim_verify_reason = dkim_exim_expand_query(DKIM_VERIFY_REASON); | |
dd33c4e6 | 387 | |
18067c75 JH |
388 | if ((rc = dkim_acl_call(id, res_ptr, user_msgptr, log_msgptr)) != OK) |
389 | return rc; | |
80a47a2c | 390 | } |
18067c75 JH |
391 | |
392 | if (rc != -1) | |
393 | return rc; | |
394 | ||
395 | /* No matching sig found. Call ACL once anyway. */ | |
396 | ||
397 | dkim_cur_sig = NULL; | |
398 | return dkim_acl_call(id, res_ptr, user_msgptr, log_msgptr); | |
80a47a2c TK |
399 | } |
400 | ||
401 | ||
1cfe5c1c JH |
402 | static uschar * |
403 | dkim_exim_expand_defaults(int what) | |
404 | { | |
405 | switch (what) | |
406 | { | |
407 | case DKIM_ALGO: return US""; | |
408 | case DKIM_BODYLENGTH: return US"9999999999999"; | |
409 | case DKIM_CANON_BODY: return US""; | |
410 | case DKIM_CANON_HEADERS: return US""; | |
411 | case DKIM_COPIEDHEADERS: return US""; | |
412 | case DKIM_CREATED: return US"0"; | |
413 | case DKIM_EXPIRES: return US"9999999999999"; | |
414 | case DKIM_HEADERNAMES: return US""; | |
415 | case DKIM_IDENTITY: return US""; | |
416 | case DKIM_KEY_GRANULARITY: return US"*"; | |
417 | case DKIM_KEY_SRVTYPE: return US"*"; | |
418 | case DKIM_KEY_NOTES: return US""; | |
419 | case DKIM_KEY_TESTING: return US"0"; | |
420 | case DKIM_NOSUBDOMAINS: return US"0"; | |
421 | case DKIM_VERIFY_STATUS: return US"none"; | |
422 | case DKIM_VERIFY_REASON: return US""; | |
423 | default: return US""; | |
424 | } | |
425 | } | |
80a47a2c | 426 | |
80a47a2c | 427 | |
1cfe5c1c JH |
428 | uschar * |
429 | dkim_exim_expand_query(int what) | |
430 | { | |
431 | if (!dkim_verify_ctx || dkim_disable_verify || !dkim_cur_sig) | |
432 | return dkim_exim_expand_defaults(what); | |
433 | ||
434 | switch (what) | |
435 | { | |
436 | case DKIM_ALGO: | |
d73e45df | 437 | return dkim_sig_to_a_tag(dkim_cur_sig); |
1cfe5c1c JH |
438 | |
439 | case DKIM_BODYLENGTH: | |
440 | return dkim_cur_sig->bodylength >= 0 | |
bb07bcd3 | 441 | ? string_sprintf("%ld", dkim_cur_sig->bodylength) |
1cfe5c1c JH |
442 | : dkim_exim_expand_defaults(what); |
443 | ||
444 | case DKIM_CANON_BODY: | |
445 | switch (dkim_cur_sig->canon_body) | |
446 | { | |
447 | case PDKIM_CANON_RELAXED: return US"relaxed"; | |
448 | case PDKIM_CANON_SIMPLE: | |
449 | default: return US"simple"; | |
80a47a2c | 450 | } |
1cfe5c1c JH |
451 | |
452 | case DKIM_CANON_HEADERS: | |
a79d8834 JH |
453 | switch (dkim_cur_sig->canon_headers) |
454 | { | |
455 | case PDKIM_CANON_RELAXED: return US"relaxed"; | |
456 | case PDKIM_CANON_SIMPLE: | |
457 | default: return US"simple"; | |
458 | } | |
1cfe5c1c JH |
459 | |
460 | case DKIM_COPIEDHEADERS: | |
461 | return dkim_cur_sig->copiedheaders | |
462 | ? US dkim_cur_sig->copiedheaders : dkim_exim_expand_defaults(what); | |
463 | ||
464 | case DKIM_CREATED: | |
465 | return dkim_cur_sig->created > 0 | |
bb07bcd3 | 466 | ? string_sprintf("%lu", dkim_cur_sig->created) |
1cfe5c1c JH |
467 | : dkim_exim_expand_defaults(what); |
468 | ||
469 | case DKIM_EXPIRES: | |
470 | return dkim_cur_sig->expires > 0 | |
bb07bcd3 | 471 | ? string_sprintf("%lu", dkim_cur_sig->expires) |
1cfe5c1c JH |
472 | : dkim_exim_expand_defaults(what); |
473 | ||
474 | case DKIM_HEADERNAMES: | |
475 | return dkim_cur_sig->headernames | |
2592e6c0 | 476 | ? dkim_cur_sig->headernames : dkim_exim_expand_defaults(what); |
1cfe5c1c JH |
477 | |
478 | case DKIM_IDENTITY: | |
479 | return dkim_cur_sig->identity | |
480 | ? US dkim_cur_sig->identity : dkim_exim_expand_defaults(what); | |
481 | ||
482 | case DKIM_KEY_GRANULARITY: | |
483 | return dkim_cur_sig->pubkey | |
484 | ? dkim_cur_sig->pubkey->granularity | |
485 | ? US dkim_cur_sig->pubkey->granularity | |
486 | : dkim_exim_expand_defaults(what) | |
487 | : dkim_exim_expand_defaults(what); | |
488 | ||
489 | case DKIM_KEY_SRVTYPE: | |
490 | return dkim_cur_sig->pubkey | |
491 | ? dkim_cur_sig->pubkey->srvtype | |
492 | ? US dkim_cur_sig->pubkey->srvtype | |
493 | : dkim_exim_expand_defaults(what) | |
494 | : dkim_exim_expand_defaults(what); | |
495 | ||
496 | case DKIM_KEY_NOTES: | |
497 | return dkim_cur_sig->pubkey | |
498 | ? dkim_cur_sig->pubkey->notes | |
499 | ? US dkim_cur_sig->pubkey->notes | |
500 | : dkim_exim_expand_defaults(what) | |
501 | : dkim_exim_expand_defaults(what); | |
502 | ||
503 | case DKIM_KEY_TESTING: | |
504 | return dkim_cur_sig->pubkey | |
505 | ? dkim_cur_sig->pubkey->testing | |
506 | ? US"1" | |
507 | : dkim_exim_expand_defaults(what) | |
508 | : dkim_exim_expand_defaults(what); | |
509 | ||
510 | case DKIM_NOSUBDOMAINS: | |
511 | return dkim_cur_sig->pubkey | |
512 | ? dkim_cur_sig->pubkey->no_subdomaining | |
513 | ? US"1" | |
514 | : dkim_exim_expand_defaults(what) | |
515 | : dkim_exim_expand_defaults(what); | |
516 | ||
517 | case DKIM_VERIFY_STATUS: | |
518 | switch (dkim_cur_sig->verify_status) | |
519 | { | |
520 | case PDKIM_VERIFY_INVALID: return US"invalid"; | |
521 | case PDKIM_VERIFY_FAIL: return US"fail"; | |
522 | case PDKIM_VERIFY_PASS: return US"pass"; | |
523 | case PDKIM_VERIFY_NONE: | |
524 | default: return US"none"; | |
80a47a2c | 525 | } |
80a47a2c | 526 | |
1cfe5c1c JH |
527 | case DKIM_VERIFY_REASON: |
528 | switch (dkim_cur_sig->verify_ext_status) | |
529 | { | |
530 | case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: | |
531 | return US"pubkey_unavailable"; | |
df3def24 JH |
532 | case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD:return US"pubkey_dns_syntax"; |
533 | case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: return US"pubkey_der_syntax"; | |
1cfe5c1c JH |
534 | case PDKIM_VERIFY_FAIL_BODY: return US"bodyhash_mismatch"; |
535 | case PDKIM_VERIFY_FAIL_MESSAGE: return US"signature_incorrect"; | |
536 | } | |
80a47a2c | 537 | |
1cfe5c1c JH |
538 | default: |
539 | return US""; | |
80a47a2c TK |
540 | } |
541 | } | |
542 | ||
543 | ||
0b8f4f1a | 544 | /* Generate signatures for the given file. |
42055a33 | 545 | If a prefix is given, prepend it to the file for the calculations. |
0b8f4f1a JH |
546 | |
547 | Return: | |
548 | NULL: error; error string written | |
549 | string: signature header(s), or a zero-length string (not an error) | |
42055a33 JH |
550 | */ |
551 | ||
acec9514 | 552 | gstring * |
42055a33 JH |
553 | dkim_exim_sign(int fd, off_t off, uschar * prefix, |
554 | struct ob_dkim * dkim, const uschar ** errstr) | |
55414b25 | 555 | { |
e983e85a | 556 | const uschar * dkim_domain; |
1cfe5c1c | 557 | int sep = 0; |
acec9514 | 558 | gstring * seen_doms = NULL; |
9e70917d JH |
559 | pdkim_ctx ctx; |
560 | pdkim_signature * sig; | |
acec9514 | 561 | gstring * sigbuf; |
1cfe5c1c JH |
562 | int pdkim_rc; |
563 | int sread; | |
ef698bf6 | 564 | uschar buf[4096]; |
1cfe5c1c JH |
565 | int save_errno = 0; |
566 | int old_pool = store_pool; | |
7c6ec81b | 567 | uschar * errwhen; |
1cfe5c1c JH |
568 | |
569 | store_pool = POOL_MAIN; | |
570 | ||
9e70917d JH |
571 | pdkim_init_context(&ctx, dkim->dot_stuffed, &dkim_exim_query_dns_txt); |
572 | ||
e983e85a | 573 | if (!(dkim_domain = expand_cstring(dkim->dkim_domain))) |
1cfe5c1c | 574 | /* expansion error, do not send message. */ |
7c6ec81b | 575 | { errwhen = US"dkim_domain"; goto expand_bad; } |
1cfe5c1c JH |
576 | |
577 | /* Set $dkim_domain expansion variable to each unique domain in list. */ | |
578 | ||
42055a33 | 579 | while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, NULL, 0))) |
1cfe5c1c | 580 | { |
9e70917d JH |
581 | const uschar * dkim_sel; |
582 | int sel_sep = 0; | |
583 | ||
42055a33 | 584 | if (dkim_signing_domain[0] == '\0') |
1cfe5c1c JH |
585 | continue; |
586 | ||
587 | /* Only sign once for each domain, no matter how often it | |
588 | appears in the expanded list. */ | |
589 | ||
9e70917d JH |
590 | if (match_isinlist(dkim_signing_domain, CUSS &seen_doms, |
591 | 0, NULL, NULL, MCL_STRING, TRUE, NULL) == OK) | |
592 | continue; | |
1cfe5c1c | 593 | |
acec9514 | 594 | seen_doms = string_append_listele(seen_doms, ':', dkim_signing_domain); |
1cfe5c1c | 595 | |
9e70917d JH |
596 | /* Set $dkim_selector expansion variable to each selector in list, |
597 | for this domain. */ | |
1cfe5c1c | 598 | |
9e70917d | 599 | if (!(dkim_sel = expand_string(dkim->dkim_selector))) |
e983e85a | 600 | if (!(dkim_signing_selector = expand_string(dkim->dkim_selector))) |
7c6ec81b | 601 | { errwhen = US"dkim_selector"; goto expand_bad; } |
1cfe5c1c | 602 | |
9e70917d JH |
603 | while ((dkim_signing_selector = string_nextinlist(&dkim_sel, &sel_sep, |
604 | NULL, 0))) | |
1cfe5c1c | 605 | { |
9e70917d JH |
606 | uschar * dkim_canon_expanded; |
607 | int pdkim_canon; | |
608 | uschar * dkim_sign_headers_expanded = NULL; | |
609 | uschar * dkim_private_key_expanded; | |
610 | uschar * dkim_hash_expanded; | |
7c6ec81b | 611 | uschar * dkim_identity_expanded = NULL; |
80a47a2c | 612 | |
9e70917d | 613 | /* Get canonicalization to use */ |
1cfe5c1c | 614 | |
9e70917d JH |
615 | dkim_canon_expanded = dkim->dkim_canon |
616 | ? expand_string(dkim->dkim_canon) : US"relaxed"; | |
7c6ec81b JH |
617 | if (!dkim_canon_expanded) /* expansion error, do not send message. */ |
618 | { errwhen = US"dkim_canon"; goto expand_bad; } | |
1cfe5c1c | 619 | |
9e70917d JH |
620 | if (Ustrcmp(dkim_canon_expanded, "relaxed") == 0) |
621 | pdkim_canon = PDKIM_CANON_RELAXED; | |
622 | else if (Ustrcmp(dkim_canon_expanded, "simple") == 0) | |
623 | pdkim_canon = PDKIM_CANON_SIMPLE; | |
624 | else | |
625 | { | |
626 | log_write(0, LOG_MAIN, | |
627 | "DKIM: unknown canonicalization method '%s', defaulting to 'relaxed'.\n", | |
628 | dkim_canon_expanded); | |
629 | pdkim_canon = PDKIM_CANON_RELAXED; | |
630 | } | |
1cfe5c1c | 631 | |
7c6ec81b JH |
632 | if ( dkim->dkim_sign_headers |
633 | && !(dkim_sign_headers_expanded = expand_string(dkim->dkim_sign_headers))) | |
634 | { errwhen = US"dkim_sign_header"; goto expand_bad; } | |
635 | /* else pass NULL, which means default header list */ | |
1cfe5c1c | 636 | |
9e70917d | 637 | /* Get private key to use. */ |
e983e85a | 638 | |
9e70917d | 639 | if (!(dkim_private_key_expanded = expand_string(dkim->dkim_private_key))) |
7c6ec81b | 640 | { errwhen = US"dkim_private_key"; goto expand_bad; } |
80a47a2c | 641 | |
9e70917d JH |
642 | if ( Ustrlen(dkim_private_key_expanded) == 0 |
643 | || Ustrcmp(dkim_private_key_expanded, "0") == 0 | |
644 | || Ustrcmp(dkim_private_key_expanded, "false") == 0 | |
645 | ) | |
646 | continue; /* don't sign, but no error */ | |
647 | ||
648 | if (dkim_private_key_expanded[0] == '/') | |
1cfe5c1c | 649 | { |
9e70917d JH |
650 | int privkey_fd, off = 0, len; |
651 | ||
652 | /* Looks like a filename, load the private key. */ | |
653 | ||
654 | memset(big_buffer, 0, big_buffer_size); | |
655 | ||
656 | if ((privkey_fd = open(CS dkim_private_key_expanded, O_RDONLY)) < 0) | |
59d98039 | 657 | { |
9e70917d JH |
658 | log_write(0, LOG_MAIN | LOG_PANIC, "unable to open " |
659 | "private key file for reading: %s", | |
59d98039 JH |
660 | dkim_private_key_expanded); |
661 | goto bad; | |
662 | } | |
9e70917d JH |
663 | |
664 | do | |
665 | { | |
666 | if ((len = read(privkey_fd, big_buffer + off, big_buffer_size - 2 - off)) < 0) | |
667 | { | |
668 | (void) close(privkey_fd); | |
669 | log_write(0, LOG_MAIN|LOG_PANIC, "unable to read private key file: %s", | |
670 | dkim_private_key_expanded); | |
671 | goto bad; | |
672 | } | |
673 | off += len; | |
674 | } | |
675 | while (len > 0); | |
676 | ||
677 | (void) close(privkey_fd); | |
678 | big_buffer[off] = '\0'; | |
679 | dkim_private_key_expanded = big_buffer; | |
1ac6b2e7 | 680 | } |
80a47a2c | 681 | |
9e70917d | 682 | if (!(dkim_hash_expanded = expand_string(dkim->dkim_hash))) |
7c6ec81b JH |
683 | { errwhen = US"dkim_hash"; goto expand_bad; } |
684 | ||
685 | if (dkim->dkim_identity) | |
686 | if (!(dkim_identity_expanded = expand_string(dkim->dkim_identity))) | |
687 | { errwhen = US"dkim_identity"; goto expand_bad; } | |
688 | else if (!*dkim_identity_expanded) | |
689 | dkim_identity_expanded = NULL; | |
1cfe5c1c | 690 | |
9e70917d JH |
691 | /*XXX so we currently nail signing to RSA + this hash. |
692 | Need to extract algo from privkey and check for disallowed combos. */ | |
d73e45df | 693 | |
9e70917d JH |
694 | if (!(sig = pdkim_init_sign(&ctx, dkim_signing_domain, |
695 | dkim_signing_selector, | |
696 | dkim_private_key_expanded, | |
697 | dkim_hash_expanded, | |
698 | errstr | |
699 | ))) | |
700 | goto bad; | |
701 | dkim_private_key_expanded[0] = '\0'; | |
702 | ||
703 | pdkim_set_optional(sig, | |
704 | CS dkim_sign_headers_expanded, | |
27fd1318 | 705 | CS dkim_identity_expanded, |
9e70917d JH |
706 | pdkim_canon, |
707 | pdkim_canon, -1, 0, 0); | |
708 | ||
cf1cce5e JH |
709 | if (!pdkim_set_bodyhash(&ctx, sig)) |
710 | goto bad; | |
711 | ||
9e70917d JH |
712 | if (!ctx.sig) /* link sig to context chain */ |
713 | ctx.sig = sig; | |
714 | else | |
715 | { | |
716 | pdkim_signature * n = ctx.sig; | |
717 | while (n->next) n = n->next; | |
718 | n->next = sig; | |
719 | } | |
80a47a2c | 720 | } |
9e70917d | 721 | } |
0b8f4f1a JH |
722 | if (!ctx.sig) |
723 | { | |
724 | DEBUG(D_transport) debug_printf("DKIM: no viable signatures to use\n"); | |
725 | sigbuf = string_get(1); /* return a zero-len string */ | |
726 | goto CLEANUP; | |
727 | } | |
80a47a2c | 728 | |
d011368a | 729 | if (prefix && (pdkim_rc = pdkim_feed(&ctx, prefix, Ustrlen(prefix))) != PDKIM_OK) |
0b8f4f1a | 730 | goto pk_bad; |
80a47a2c | 731 | |
9e70917d JH |
732 | if (lseek(fd, off, SEEK_SET) < 0) |
733 | sread = -1; | |
734 | else | |
735 | while ((sread = read(fd, &buf, sizeof(buf))) > 0) | |
736 | if ((pdkim_rc = pdkim_feed(&ctx, buf, sread)) != PDKIM_OK) | |
737 | goto pk_bad; | |
80a47a2c | 738 | |
9e70917d JH |
739 | /* Handle failed read above. */ |
740 | if (sread == -1) | |
741 | { | |
742 | debug_printf("DKIM: Error reading -K file.\n"); | |
743 | save_errno = errno; | |
744 | goto bad; | |
80a47a2c | 745 | } |
a8e1eeba | 746 | |
9e70917d JH |
747 | /* Build string of headers, one per signature */ |
748 | ||
749 | if ((pdkim_rc = pdkim_feed_finish(&ctx, &sig, errstr)) != PDKIM_OK) | |
750 | goto pk_bad; | |
751 | ||
acec9514 JH |
752 | for (sigbuf = NULL; sig; sig = sig->next) |
753 | sigbuf = string_append(sigbuf, 2, US sig->signature_header, US"\r\n"); | |
9e70917d | 754 | |
1cfe5c1c | 755 | CLEANUP: |
0b8f4f1a | 756 | (void) string_from_gstring(sigbuf); |
f7302073 JH |
757 | store_pool = old_pool; |
758 | errno = save_errno; | |
9e70917d | 759 | return sigbuf; |
f7302073 JH |
760 | |
761 | pk_bad: | |
762 | log_write(0, LOG_MAIN|LOG_PANIC, | |
763 | "DKIM: signing failed: %.100s", pdkim_errstr(pdkim_rc)); | |
764 | bad: | |
9e70917d | 765 | sigbuf = NULL; |
f7302073 | 766 | goto CLEANUP; |
7c6ec81b JH |
767 | |
768 | expand_bad: | |
769 | log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand %s: %s", | |
770 | errwhen, expand_string_message); | |
771 | goto bad; | |
93f2d376 | 772 | } |
80a47a2c | 773 | |
970424a5 JH |
774 | # endif /*!MACRO_PREDEF*/ |
775 | #endif /*!DISABLE_DKIM*/ |