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80a47a2c TK |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
f9ba5e22 | 5 | /* Copyright (c) University of Cambridge, 1995 - 2018 */ |
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 | ||
617d3932 | 29 | pdkim_ctx dkim_sign_ctx; |
80a47a2c | 30 | |
ca9cb170 | 31 | int dkim_verify_oldpool; |
1cfe5c1c | 32 | pdkim_ctx *dkim_verify_ctx = NULL; |
1cfe5c1c | 33 | pdkim_signature *dkim_cur_sig = NULL; |
b9df1829 | 34 | static const uschar * dkim_collect_error = NULL; |
80a47a2c | 35 | |
64b67b65 JH |
36 | #define DKIM_MAX_SIGNATURES 20 |
37 | ||
d73e45df JH |
38 | |
39 | ||
40 | /*XXX the caller only uses the first record if we return multiple. | |
d73e45df JH |
41 | */ |
42 | ||
617d3932 JH |
43 | uschar * |
44 | dkim_exim_query_dns_txt(uschar * name) | |
1cfe5c1c JH |
45 | { |
46 | dns_answer dnsa; | |
47 | dns_scan dnss; | |
48 | dns_record *rr; | |
1eedc10f | 49 | gstring * g = NULL; |
80a47a2c | 50 | |
1cfe5c1c | 51 | lookup_dnssec_authenticated = NULL; |
617d3932 | 52 | if (dns_lookup(&dnsa, name, T_TXT, NULL) != DNS_SUCCEED) |
1eedc10f | 53 | return NULL; /*XXX better error detail? logging? */ |
80a47a2c | 54 | |
1cfe5c1c | 55 | /* Search for TXT record */ |
80a47a2c | 56 | |
1cfe5c1c JH |
57 | for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS); |
58 | rr; | |
59 | rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) | |
60 | if (rr->type == T_TXT) | |
61 | { | |
80a47a2c | 62 | int rr_offset = 0; |
1cfe5c1c JH |
63 | |
64 | /* Copy record content to the answer buffer */ | |
65 | ||
66 | while (rr_offset < rr->size) | |
67 | { | |
68 | uschar len = rr->data[rr_offset++]; | |
1eedc10f JH |
69 | |
70 | g = string_catn(g, US(rr->data + rr_offset), len); | |
71 | if (g->ptr >= PDKIM_DNS_TXT_MAX_RECLEN) | |
72 | goto bad; | |
73 | ||
1cfe5c1c | 74 | rr_offset += len; |
4263f395 | 75 | } |
dd33c4e6 HSHR |
76 | |
77 | /* check if this looks like a DKIM record */ | |
d011368a | 78 | if (Ustrncmp(g->s, "v=", 2) != 0 || strncasecmp(CS g->s, "v=dkim", 6) == 0) |
1eedc10f | 79 | { |
617d3932 | 80 | gstring_reset_unused(g); |
1eedc10f JH |
81 | return string_from_gstring(g); |
82 | } | |
83 | ||
84 | if (g) g->ptr = 0; /* overwrite previous record */ | |
80a47a2c | 85 | } |
80a47a2c | 86 | |
1eedc10f JH |
87 | bad: |
88 | if (g) store_reset(g); | |
89 | return NULL; /*XXX better error detail? logging? */ | |
80a47a2c TK |
90 | } |
91 | ||
92 | ||
2592e6c0 JH |
93 | void |
94 | dkim_exim_init(void) | |
95 | { | |
96 | pdkim_init(); | |
97 | } | |
98 | ||
99 | ||
ca9cb170 | 100 | |
1cfe5c1c | 101 | void |
e983e85a | 102 | dkim_exim_verify_init(BOOL dot_stuffing) |
1cfe5c1c | 103 | { |
ca9cb170 JH |
104 | /* There is a store-reset between header & body reception |
105 | so cannot use the main pool. Any allocs done by Exim | |
106 | memory-handling must use the perm pool. */ | |
107 | ||
108 | dkim_verify_oldpool = store_pool; | |
109 | store_pool = POOL_PERM; | |
110 | ||
1cfe5c1c | 111 | /* Free previous context if there is one */ |
80a47a2c | 112 | |
1cfe5c1c JH |
113 | if (dkim_verify_ctx) |
114 | pdkim_free_ctx(dkim_verify_ctx); | |
80a47a2c | 115 | |
1cfe5c1c | 116 | /* Create new context */ |
80a47a2c | 117 | |
e983e85a | 118 | dkim_verify_ctx = pdkim_init_verify(&dkim_exim_query_dns_txt, dot_stuffing); |
64b67b65 | 119 | dkim_collect_input = dkim_verify_ctx ? DKIM_MAX_SIGNATURES : 0; |
b9df1829 | 120 | dkim_collect_error = NULL; |
ca9cb170 | 121 | |
584e96c6 JH |
122 | /* Start feed up with any cached data */ |
123 | receive_get_cache(); | |
124 | ||
ca9cb170 | 125 | store_pool = dkim_verify_oldpool; |
80a47a2c TK |
126 | } |
127 | ||
128 | ||
1cfe5c1c JH |
129 | void |
130 | dkim_exim_verify_feed(uschar * data, int len) | |
131 | { | |
f7302073 JH |
132 | int rc; |
133 | ||
ca9cb170 | 134 | store_pool = POOL_PERM; |
1cfe5c1c | 135 | if ( dkim_collect_input |
ef698bf6 | 136 | && (rc = pdkim_feed(dkim_verify_ctx, data, len)) != PDKIM_OK) |
f7302073 | 137 | { |
b9df1829 | 138 | dkim_collect_error = pdkim_errstr(rc); |
f7302073 | 139 | log_write(0, LOG_MAIN, |
b9df1829 | 140 | "DKIM: validation error: %.100s", dkim_collect_error); |
64b67b65 | 141 | dkim_collect_input = 0; |
f7302073 | 142 | } |
ca9cb170 | 143 | store_pool = dkim_verify_oldpool; |
80a47a2c TK |
144 | } |
145 | ||
146 | ||
a79d8834 JH |
147 | /* Log the result for the given signature */ |
148 | static void | |
149 | dkim_exim_verify_log_sig(pdkim_signature * sig) | |
1cfe5c1c | 150 | { |
cc55f420 | 151 | gstring * logmsg; |
a79d8834 JH |
152 | uschar * s; |
153 | ||
cc55f420 JH |
154 | if (!sig) return; |
155 | ||
6678c382 | 156 | /* Remember the domain for the first pass result */ |
dfbcb5ac | 157 | |
2c47372f JH |
158 | if ( !dkim_verify_overall |
159 | && dkim_verify_status | |
160 | ? Ustrcmp(dkim_verify_status, US"pass") == 0 | |
161 | : sig->verify_status == PDKIM_VERIFY_PASS | |
162 | ) | |
163 | dkim_verify_overall = string_copy(sig->domain); | |
164 | ||
6678c382 JH |
165 | /* Rewrite the sig result if the ACL overrode it. This is only |
166 | needed because the DMARC code (sigh) peeks at the dkim sigs. | |
167 | Mark the sig for this having been done. */ | |
168 | ||
169 | if ( dkim_verify_status | |
170 | && ( dkim_verify_status != dkim_exim_expand_query(DKIM_VERIFY_STATUS) | |
171 | || dkim_verify_reason != dkim_exim_expand_query(DKIM_VERIFY_REASON) | |
172 | ) ) | |
173 | { /* overridden by ACL */ | |
174 | sig->verify_ext_status = -1; | |
175 | if (Ustrcmp(dkim_verify_status, US"fail") == 0) | |
176 | sig->verify_status = PDKIM_VERIFY_POLICY | PDKIM_VERIFY_FAIL; | |
177 | else if (Ustrcmp(dkim_verify_status, US"invalid") == 0) | |
178 | sig->verify_status = PDKIM_VERIFY_POLICY | PDKIM_VERIFY_INVALID; | |
179 | else if (Ustrcmp(dkim_verify_status, US"none") == 0) | |
180 | sig->verify_status = PDKIM_VERIFY_POLICY | PDKIM_VERIFY_NONE; | |
181 | else if (Ustrcmp(dkim_verify_status, US"pass") == 0) | |
182 | sig->verify_status = PDKIM_VERIFY_POLICY | PDKIM_VERIFY_PASS; | |
183 | else | |
184 | sig->verify_status = -1; | |
185 | } | |
186 | ||
2c47372f JH |
187 | if (!LOGGING(dkim_verbose)) return; |
188 | ||
6678c382 | 189 | |
aaaa94ea | 190 | logmsg = string_catn(NULL, US"DKIM: ", 6); |
a79d8834 JH |
191 | if (!(s = sig->domain)) s = US"<UNSET>"; |
192 | logmsg = string_append(logmsg, 2, "d=", s); | |
193 | if (!(s = sig->selector)) s = US"<UNSET>"; | |
194 | logmsg = string_append(logmsg, 2, " s=", s); | |
52f12a7c JH |
195 | logmsg = string_fmt_append(logmsg, " c=%s/%s a=%s b=" SIZE_T_FMT, |
196 | sig->canon_headers == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", | |
197 | sig->canon_body == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", | |
198 | dkim_sig_to_a_tag(sig), | |
199 | (int)sig->sighash.len > -1 ? sig->sighash.len * 8 : (size_t)0); | |
a79d8834 | 200 | if ((s= sig->identity)) logmsg = string_append(logmsg, 2, " i=", s); |
52f12a7c JH |
201 | if (sig->created > 0) logmsg = string_fmt_append(logmsg, " t=%lu", |
202 | sig->created); | |
203 | if (sig->expires > 0) logmsg = string_fmt_append(logmsg, " x=%lu", | |
204 | sig->expires); | |
205 | if (sig->bodylength > -1) logmsg = string_fmt_append(logmsg, " l=%lu", | |
206 | sig->bodylength); | |
a79d8834 | 207 | |
dfbcb5ac JH |
208 | if (sig->verify_status & PDKIM_VERIFY_POLICY) |
209 | logmsg = string_append(logmsg, 5, | |
210 | US" [", dkim_verify_status, US" - ", dkim_verify_reason, US"]"); | |
211 | else | |
1cfe5c1c JH |
212 | switch (sig->verify_status) |
213 | { | |
214 | case PDKIM_VERIFY_NONE: | |
aaaa94ea | 215 | logmsg = string_cat(logmsg, US" [not verified]"); |
80a47a2c | 216 | break; |
1cfe5c1c JH |
217 | |
218 | case PDKIM_VERIFY_INVALID: | |
aaaa94ea | 219 | logmsg = string_cat(logmsg, US" [invalid - "); |
1cfe5c1c JH |
220 | switch (sig->verify_ext_status) |
221 | { | |
222 | case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: | |
acec9514 | 223 | logmsg = string_cat(logmsg, |
aaaa94ea | 224 | US"public key record (currently?) unavailable]"); |
1cfe5c1c JH |
225 | break; |
226 | ||
227 | case PDKIM_VERIFY_INVALID_BUFFER_SIZE: | |
aaaa94ea | 228 | logmsg = string_cat(logmsg, US"overlong public key record]"); |
1cfe5c1c JH |
229 | break; |
230 | ||
df3def24 JH |
231 | case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: |
232 | case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: | |
aaaa94ea | 233 | logmsg = string_cat(logmsg, US"syntax error in public key record]"); |
1cfe5c1c | 234 | break; |
07eeb4df | 235 | |
a79d8834 | 236 | case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: |
aaaa94ea | 237 | logmsg = string_cat(logmsg, US"signature tag missing or invalid]"); |
a79d8834 | 238 | break; |
07eeb4df | 239 | |
a79d8834 | 240 | case PDKIM_VERIFY_INVALID_DKIM_VERSION: |
aaaa94ea | 241 | logmsg = string_cat(logmsg, US"unsupported DKIM version]"); |
a79d8834 | 242 | break; |
1cfe5c1c JH |
243 | |
244 | default: | |
aaaa94ea | 245 | logmsg = string_cat(logmsg, US"unspecified problem]"); |
1cfe5c1c | 246 | } |
80a47a2c | 247 | break; |
1cfe5c1c JH |
248 | |
249 | case PDKIM_VERIFY_FAIL: | |
aaaa94ea | 250 | logmsg = string_cat(logmsg, US" [verification failed - "); |
1cfe5c1c JH |
251 | switch (sig->verify_ext_status) |
252 | { | |
253 | case PDKIM_VERIFY_FAIL_BODY: | |
acec9514 | 254 | logmsg = string_cat(logmsg, |
aaaa94ea | 255 | US"body hash mismatch (body probably modified in transit)]"); |
1cfe5c1c JH |
256 | break; |
257 | ||
258 | case PDKIM_VERIFY_FAIL_MESSAGE: | |
acec9514 | 259 | logmsg = string_cat(logmsg, |
aaaa94ea JH |
260 | US"signature did not verify " |
261 | "(headers probably modified in transit)]"); | |
dfbcb5ac | 262 | break; |
1cfe5c1c JH |
263 | |
264 | default: | |
aaaa94ea | 265 | logmsg = string_cat(logmsg, US"unspecified reason]"); |
1cfe5c1c | 266 | } |
80a47a2c | 267 | break; |
1cfe5c1c JH |
268 | |
269 | case PDKIM_VERIFY_PASS: | |
aaaa94ea | 270 | logmsg = string_cat(logmsg, US" [verification succeeded]"); |
80a47a2c TK |
271 | break; |
272 | } | |
a79d8834 | 273 | |
aaaa94ea | 274 | log_write(0, LOG_MAIN, "%s", string_from_gstring(logmsg)); |
a79d8834 JH |
275 | return; |
276 | } | |
277 | ||
80a47a2c | 278 | |
a79d8834 JH |
279 | /* Log a line for each signature */ |
280 | void | |
281 | dkim_exim_verify_log_all(void) | |
282 | { | |
283 | pdkim_signature * sig; | |
284 | for (sig = dkim_signatures; sig; sig = sig->next) dkim_exim_verify_log_sig(sig); | |
285 | } | |
1cfe5c1c | 286 | |
80a47a2c | 287 | |
a79d8834 JH |
288 | void |
289 | dkim_exim_verify_finish(void) | |
290 | { | |
291 | pdkim_signature * sig; | |
292 | int rc; | |
293 | gstring * g = NULL; | |
286b9d5f | 294 | const uschar * errstr = NULL; |
a79d8834 JH |
295 | |
296 | store_pool = POOL_PERM; | |
297 | ||
298 | /* Delete eventual previous signature chain */ | |
299 | ||
300 | dkim_signers = NULL; | |
301 | dkim_signatures = NULL; | |
302 | ||
303 | if (dkim_collect_error) | |
304 | { | |
305 | log_write(0, LOG_MAIN, | |
306 | "DKIM: Error during validation, disabling signature verification: %.100s", | |
307 | dkim_collect_error); | |
8768d548 | 308 | f.dkim_disable_verify = TRUE; |
a79d8834 JH |
309 | goto out; |
310 | } | |
311 | ||
64b67b65 | 312 | dkim_collect_input = 0; |
a79d8834 JH |
313 | |
314 | /* Finish DKIM operation and fetch link to signatures chain */ | |
315 | ||
b4757e36 JH |
316 | rc = pdkim_feed_finish(dkim_verify_ctx, (pdkim_signature **)&dkim_signatures, |
317 | &errstr); | |
286b9d5f JH |
318 | if (rc != PDKIM_OK && errstr) |
319 | log_write(0, LOG_MAIN, "DKIM: validation error: %s", errstr); | |
a79d8834 JH |
320 | |
321 | /* Build a colon-separated list of signing domains (and identities, if present) in dkim_signers */ | |
322 | ||
323 | for (sig = dkim_signatures; sig; sig = sig->next) | |
324 | { | |
325 | if (sig->domain) g = string_append_listele(g, ':', sig->domain); | |
326 | if (sig->identity) g = string_append_listele(g, ':', sig->identity); | |
80a47a2c TK |
327 | } |
328 | ||
acec9514 JH |
329 | if (g) dkim_signers = g->s; |
330 | ||
ca9cb170 JH |
331 | out: |
332 | store_pool = dkim_verify_oldpool; | |
80a47a2c TK |
333 | } |
334 | ||
335 | ||
18067c75 JH |
336 | |
337 | /* Args as per dkim_exim_acl_run() below */ | |
338 | static int | |
339 | dkim_acl_call(uschar * id, gstring ** res_ptr, | |
340 | uschar ** user_msgptr, uschar ** log_msgptr) | |
341 | { | |
342 | int rc; | |
343 | DEBUG(D_receive) | |
344 | debug_printf("calling acl_smtp_dkim for dkim_cur_signer='%s'\n", id); | |
345 | ||
346 | rc = acl_check(ACL_WHERE_DKIM, NULL, acl_smtp_dkim, user_msgptr, log_msgptr); | |
347 | dkim_exim_verify_log_sig(dkim_cur_sig); | |
348 | *res_ptr = string_append_listele(*res_ptr, ':', dkim_verify_status); | |
349 | return rc; | |
350 | } | |
351 | ||
352 | ||
353 | ||
354 | /* For the given identity, run the DKIM ACL once for each matching signature. | |
355 | ||
356 | Arguments | |
357 | id Identity to look for in dkim signatures | |
358 | res_ptr ptr to growable string-list of status results, | |
359 | appended to per ACL run | |
360 | user_msgptr where to put a user error (for SMTP response) | |
361 | log_msgptr where to put a logging message (not for SMTP response) | |
362 | ||
363 | Returns: OK access is granted by an ACCEPT verb | |
364 | DISCARD access is granted by a DISCARD verb | |
365 | FAIL access is denied | |
366 | FAIL_DROP access is denied; drop the connection | |
367 | DEFER can't tell at the moment | |
368 | ERROR disaster | |
369 | */ | |
370 | ||
371 | int | |
372 | dkim_exim_acl_run(uschar * id, gstring ** res_ptr, | |
373 | uschar ** user_msgptr, uschar ** log_msgptr) | |
1cfe5c1c JH |
374 | { |
375 | pdkim_signature * sig; | |
376 | uschar * cmp_val; | |
18067c75 | 377 | int rc = -1; |
1cfe5c1c | 378 | |
cc55f420 JH |
379 | dkim_verify_status = US"none"; |
380 | dkim_verify_reason = US""; | |
1cfe5c1c JH |
381 | dkim_cur_signer = id; |
382 | ||
8768d548 | 383 | if (f.dkim_disable_verify || !id || !dkim_verify_ctx) |
18067c75 | 384 | return OK; |
1cfe5c1c | 385 | |
18067c75 | 386 | /* Find signatures to run ACL on */ |
1cfe5c1c JH |
387 | |
388 | for (sig = dkim_signatures; sig; sig = sig->next) | |
389 | if ( (cmp_val = Ustrchr(id, '@') != NULL ? US sig->identity : US sig->domain) | |
390 | && strcmpic(cmp_val, id) == 0 | |
391 | ) | |
392 | { | |
1cfe5c1c | 393 | /* The "dkim_domain" and "dkim_selector" expansion variables have |
18067c75 JH |
394 | related globals, since they are used in the signing code too. |
395 | Instead of inventing separate names for verification, we set | |
396 | them here. This is easy since a domain and selector is guaranteed | |
397 | to be in a signature. The other dkim_* expansion items are | |
398 | dynamically fetched from dkim_cur_sig at expansion time (see | |
b4757e36 | 399 | dkim_exim_expand_query() below). */ |
1cfe5c1c | 400 | |
18067c75 | 401 | dkim_cur_sig = sig; |
1cfe5c1c JH |
402 | dkim_signing_domain = US sig->domain; |
403 | dkim_signing_selector = US sig->selector; | |
dcd03763 | 404 | dkim_key_length = sig->sighash.len * 8; |
a79d8834 JH |
405 | |
406 | /* These two return static strings, so we can compare the addr | |
407 | later to see if the ACL overwrote them. Check that when logging */ | |
408 | ||
409 | dkim_verify_status = dkim_exim_expand_query(DKIM_VERIFY_STATUS); | |
410 | dkim_verify_reason = dkim_exim_expand_query(DKIM_VERIFY_REASON); | |
dd33c4e6 | 411 | |
18067c75 JH |
412 | if ((rc = dkim_acl_call(id, res_ptr, user_msgptr, log_msgptr)) != OK) |
413 | return rc; | |
80a47a2c | 414 | } |
18067c75 JH |
415 | |
416 | if (rc != -1) | |
417 | return rc; | |
418 | ||
419 | /* No matching sig found. Call ACL once anyway. */ | |
420 | ||
421 | dkim_cur_sig = NULL; | |
422 | return dkim_acl_call(id, res_ptr, user_msgptr, log_msgptr); | |
80a47a2c TK |
423 | } |
424 | ||
425 | ||
1cfe5c1c JH |
426 | static uschar * |
427 | dkim_exim_expand_defaults(int what) | |
428 | { | |
429 | switch (what) | |
430 | { | |
431 | case DKIM_ALGO: return US""; | |
432 | case DKIM_BODYLENGTH: return US"9999999999999"; | |
433 | case DKIM_CANON_BODY: return US""; | |
434 | case DKIM_CANON_HEADERS: return US""; | |
435 | case DKIM_COPIEDHEADERS: return US""; | |
436 | case DKIM_CREATED: return US"0"; | |
437 | case DKIM_EXPIRES: return US"9999999999999"; | |
438 | case DKIM_HEADERNAMES: return US""; | |
439 | case DKIM_IDENTITY: return US""; | |
440 | case DKIM_KEY_GRANULARITY: return US"*"; | |
441 | case DKIM_KEY_SRVTYPE: return US"*"; | |
442 | case DKIM_KEY_NOTES: return US""; | |
443 | case DKIM_KEY_TESTING: return US"0"; | |
444 | case DKIM_NOSUBDOMAINS: return US"0"; | |
445 | case DKIM_VERIFY_STATUS: return US"none"; | |
446 | case DKIM_VERIFY_REASON: return US""; | |
447 | default: return US""; | |
448 | } | |
449 | } | |
80a47a2c | 450 | |
80a47a2c | 451 | |
1cfe5c1c JH |
452 | uschar * |
453 | dkim_exim_expand_query(int what) | |
454 | { | |
8768d548 | 455 | if (!dkim_verify_ctx || f.dkim_disable_verify || !dkim_cur_sig) |
1cfe5c1c JH |
456 | return dkim_exim_expand_defaults(what); |
457 | ||
458 | switch (what) | |
459 | { | |
460 | case DKIM_ALGO: | |
d73e45df | 461 | return dkim_sig_to_a_tag(dkim_cur_sig); |
1cfe5c1c JH |
462 | |
463 | case DKIM_BODYLENGTH: | |
464 | return dkim_cur_sig->bodylength >= 0 | |
bb07bcd3 | 465 | ? string_sprintf("%ld", dkim_cur_sig->bodylength) |
1cfe5c1c JH |
466 | : dkim_exim_expand_defaults(what); |
467 | ||
468 | case DKIM_CANON_BODY: | |
469 | switch (dkim_cur_sig->canon_body) | |
470 | { | |
471 | case PDKIM_CANON_RELAXED: return US"relaxed"; | |
472 | case PDKIM_CANON_SIMPLE: | |
473 | default: return US"simple"; | |
80a47a2c | 474 | } |
1cfe5c1c JH |
475 | |
476 | case DKIM_CANON_HEADERS: | |
a79d8834 JH |
477 | switch (dkim_cur_sig->canon_headers) |
478 | { | |
479 | case PDKIM_CANON_RELAXED: return US"relaxed"; | |
480 | case PDKIM_CANON_SIMPLE: | |
481 | default: return US"simple"; | |
482 | } | |
1cfe5c1c JH |
483 | |
484 | case DKIM_COPIEDHEADERS: | |
485 | return dkim_cur_sig->copiedheaders | |
486 | ? US dkim_cur_sig->copiedheaders : dkim_exim_expand_defaults(what); | |
487 | ||
488 | case DKIM_CREATED: | |
489 | return dkim_cur_sig->created > 0 | |
bb07bcd3 | 490 | ? string_sprintf("%lu", dkim_cur_sig->created) |
1cfe5c1c JH |
491 | : dkim_exim_expand_defaults(what); |
492 | ||
493 | case DKIM_EXPIRES: | |
494 | return dkim_cur_sig->expires > 0 | |
bb07bcd3 | 495 | ? string_sprintf("%lu", dkim_cur_sig->expires) |
1cfe5c1c JH |
496 | : dkim_exim_expand_defaults(what); |
497 | ||
498 | case DKIM_HEADERNAMES: | |
499 | return dkim_cur_sig->headernames | |
2592e6c0 | 500 | ? dkim_cur_sig->headernames : dkim_exim_expand_defaults(what); |
1cfe5c1c JH |
501 | |
502 | case DKIM_IDENTITY: | |
503 | return dkim_cur_sig->identity | |
504 | ? US dkim_cur_sig->identity : dkim_exim_expand_defaults(what); | |
505 | ||
506 | case DKIM_KEY_GRANULARITY: | |
507 | return dkim_cur_sig->pubkey | |
508 | ? dkim_cur_sig->pubkey->granularity | |
509 | ? US dkim_cur_sig->pubkey->granularity | |
510 | : dkim_exim_expand_defaults(what) | |
511 | : dkim_exim_expand_defaults(what); | |
512 | ||
513 | case DKIM_KEY_SRVTYPE: | |
514 | return dkim_cur_sig->pubkey | |
515 | ? dkim_cur_sig->pubkey->srvtype | |
516 | ? US dkim_cur_sig->pubkey->srvtype | |
517 | : dkim_exim_expand_defaults(what) | |
518 | : dkim_exim_expand_defaults(what); | |
519 | ||
520 | case DKIM_KEY_NOTES: | |
521 | return dkim_cur_sig->pubkey | |
522 | ? dkim_cur_sig->pubkey->notes | |
523 | ? US dkim_cur_sig->pubkey->notes | |
524 | : dkim_exim_expand_defaults(what) | |
525 | : dkim_exim_expand_defaults(what); | |
526 | ||
527 | case DKIM_KEY_TESTING: | |
528 | return dkim_cur_sig->pubkey | |
529 | ? dkim_cur_sig->pubkey->testing | |
530 | ? US"1" | |
531 | : dkim_exim_expand_defaults(what) | |
532 | : dkim_exim_expand_defaults(what); | |
533 | ||
534 | case DKIM_NOSUBDOMAINS: | |
535 | return dkim_cur_sig->pubkey | |
536 | ? dkim_cur_sig->pubkey->no_subdomaining | |
537 | ? US"1" | |
538 | : dkim_exim_expand_defaults(what) | |
539 | : dkim_exim_expand_defaults(what); | |
540 | ||
541 | case DKIM_VERIFY_STATUS: | |
542 | switch (dkim_cur_sig->verify_status) | |
543 | { | |
544 | case PDKIM_VERIFY_INVALID: return US"invalid"; | |
545 | case PDKIM_VERIFY_FAIL: return US"fail"; | |
546 | case PDKIM_VERIFY_PASS: return US"pass"; | |
547 | case PDKIM_VERIFY_NONE: | |
548 | default: return US"none"; | |
80a47a2c | 549 | } |
80a47a2c | 550 | |
1cfe5c1c JH |
551 | case DKIM_VERIFY_REASON: |
552 | switch (dkim_cur_sig->verify_ext_status) | |
553 | { | |
554 | case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: | |
555 | return US"pubkey_unavailable"; | |
df3def24 JH |
556 | case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD:return US"pubkey_dns_syntax"; |
557 | case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: return US"pubkey_der_syntax"; | |
1cfe5c1c JH |
558 | case PDKIM_VERIFY_FAIL_BODY: return US"bodyhash_mismatch"; |
559 | case PDKIM_VERIFY_FAIL_MESSAGE: return US"signature_incorrect"; | |
560 | } | |
80a47a2c | 561 | |
1cfe5c1c JH |
562 | default: |
563 | return US""; | |
80a47a2c TK |
564 | } |
565 | } | |
566 | ||
567 | ||
617d3932 JH |
568 | void |
569 | dkim_exim_sign_init(void) | |
570 | { | |
571 | int old_pool = store_pool; | |
572 | store_pool = POOL_MAIN; | |
573 | pdkim_init_context(&dkim_sign_ctx, FALSE, &dkim_exim_query_dns_txt); | |
574 | store_pool = old_pool; | |
575 | } | |
576 | ||
577 | ||
0b8f4f1a | 578 | /* Generate signatures for the given file. |
42055a33 | 579 | If a prefix is given, prepend it to the file for the calculations. |
0b8f4f1a JH |
580 | |
581 | Return: | |
582 | NULL: error; error string written | |
583 | string: signature header(s), or a zero-length string (not an error) | |
42055a33 JH |
584 | */ |
585 | ||
acec9514 | 586 | gstring * |
42055a33 JH |
587 | dkim_exim_sign(int fd, off_t off, uschar * prefix, |
588 | struct ob_dkim * dkim, const uschar ** errstr) | |
55414b25 | 589 | { |
617d3932 | 590 | const uschar * dkim_domain = NULL; |
1cfe5c1c | 591 | int sep = 0; |
acec9514 | 592 | gstring * seen_doms = NULL; |
9e70917d | 593 | pdkim_signature * sig; |
acec9514 | 594 | gstring * sigbuf; |
1cfe5c1c JH |
595 | int pdkim_rc; |
596 | int sread; | |
ef698bf6 | 597 | uschar buf[4096]; |
1cfe5c1c JH |
598 | int save_errno = 0; |
599 | int old_pool = store_pool; | |
7c6ec81b | 600 | uschar * errwhen; |
617d3932 | 601 | const uschar * s; |
1cfe5c1c | 602 | |
617d3932 JH |
603 | if (dkim->dot_stuffed) |
604 | dkim_sign_ctx.flags |= PDKIM_DOT_TERM; | |
1cfe5c1c | 605 | |
617d3932 | 606 | store_pool = POOL_MAIN; |
9e70917d | 607 | |
617d3932 | 608 | if ((s = dkim->dkim_domain) && !(dkim_domain = expand_cstring(s))) |
1cfe5c1c | 609 | /* expansion error, do not send message. */ |
7c6ec81b | 610 | { errwhen = US"dkim_domain"; goto expand_bad; } |
1cfe5c1c JH |
611 | |
612 | /* Set $dkim_domain expansion variable to each unique domain in list. */ | |
613 | ||
617d3932 JH |
614 | if (dkim_domain) |
615 | while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, NULL, 0))) | |
1cfe5c1c | 616 | { |
9e70917d JH |
617 | const uschar * dkim_sel; |
618 | int sel_sep = 0; | |
619 | ||
42055a33 | 620 | if (dkim_signing_domain[0] == '\0') |
1cfe5c1c JH |
621 | continue; |
622 | ||
623 | /* Only sign once for each domain, no matter how often it | |
624 | appears in the expanded list. */ | |
625 | ||
9e70917d JH |
626 | if (match_isinlist(dkim_signing_domain, CUSS &seen_doms, |
627 | 0, NULL, NULL, MCL_STRING, TRUE, NULL) == OK) | |
628 | continue; | |
1cfe5c1c | 629 | |
acec9514 | 630 | seen_doms = string_append_listele(seen_doms, ':', dkim_signing_domain); |
1cfe5c1c | 631 | |
9e70917d JH |
632 | /* Set $dkim_selector expansion variable to each selector in list, |
633 | for this domain. */ | |
1cfe5c1c | 634 | |
9e70917d | 635 | if (!(dkim_sel = expand_string(dkim->dkim_selector))) |
7c6ec81b | 636 | { errwhen = US"dkim_selector"; goto expand_bad; } |
1cfe5c1c | 637 | |
9e70917d JH |
638 | while ((dkim_signing_selector = string_nextinlist(&dkim_sel, &sel_sep, |
639 | NULL, 0))) | |
1cfe5c1c | 640 | { |
9e70917d JH |
641 | uschar * dkim_canon_expanded; |
642 | int pdkim_canon; | |
643 | uschar * dkim_sign_headers_expanded = NULL; | |
644 | uschar * dkim_private_key_expanded; | |
645 | uschar * dkim_hash_expanded; | |
7c6ec81b | 646 | uschar * dkim_identity_expanded = NULL; |
2bc0f45e JH |
647 | uschar * dkim_timestamps_expanded = NULL; |
648 | unsigned long tval = 0, xval = 0; | |
80a47a2c | 649 | |
9e70917d | 650 | /* Get canonicalization to use */ |
1cfe5c1c | 651 | |
9e70917d JH |
652 | dkim_canon_expanded = dkim->dkim_canon |
653 | ? expand_string(dkim->dkim_canon) : US"relaxed"; | |
7c6ec81b JH |
654 | if (!dkim_canon_expanded) /* expansion error, do not send message. */ |
655 | { errwhen = US"dkim_canon"; goto expand_bad; } | |
1cfe5c1c | 656 | |
9e70917d JH |
657 | if (Ustrcmp(dkim_canon_expanded, "relaxed") == 0) |
658 | pdkim_canon = PDKIM_CANON_RELAXED; | |
659 | else if (Ustrcmp(dkim_canon_expanded, "simple") == 0) | |
660 | pdkim_canon = PDKIM_CANON_SIMPLE; | |
661 | else | |
662 | { | |
663 | log_write(0, LOG_MAIN, | |
664 | "DKIM: unknown canonicalization method '%s', defaulting to 'relaxed'.\n", | |
665 | dkim_canon_expanded); | |
666 | pdkim_canon = PDKIM_CANON_RELAXED; | |
667 | } | |
1cfe5c1c | 668 | |
7c6ec81b JH |
669 | if ( dkim->dkim_sign_headers |
670 | && !(dkim_sign_headers_expanded = expand_string(dkim->dkim_sign_headers))) | |
671 | { errwhen = US"dkim_sign_header"; goto expand_bad; } | |
672 | /* else pass NULL, which means default header list */ | |
1cfe5c1c | 673 | |
9e70917d | 674 | /* Get private key to use. */ |
e983e85a | 675 | |
9e70917d | 676 | if (!(dkim_private_key_expanded = expand_string(dkim->dkim_private_key))) |
7c6ec81b | 677 | { errwhen = US"dkim_private_key"; goto expand_bad; } |
80a47a2c | 678 | |
9e70917d JH |
679 | if ( Ustrlen(dkim_private_key_expanded) == 0 |
680 | || Ustrcmp(dkim_private_key_expanded, "0") == 0 | |
681 | || Ustrcmp(dkim_private_key_expanded, "false") == 0 | |
682 | ) | |
683 | continue; /* don't sign, but no error */ | |
684 | ||
617d3932 JH |
685 | if ( dkim_private_key_expanded[0] == '/' |
686 | && !(dkim_private_key_expanded = | |
687 | expand_file_big_buffer(dkim_private_key_expanded))) | |
688 | goto bad; | |
80a47a2c | 689 | |
9e70917d | 690 | if (!(dkim_hash_expanded = expand_string(dkim->dkim_hash))) |
7c6ec81b JH |
691 | { errwhen = US"dkim_hash"; goto expand_bad; } |
692 | ||
693 | if (dkim->dkim_identity) | |
694 | if (!(dkim_identity_expanded = expand_string(dkim->dkim_identity))) | |
695 | { errwhen = US"dkim_identity"; goto expand_bad; } | |
696 | else if (!*dkim_identity_expanded) | |
697 | dkim_identity_expanded = NULL; | |
1cfe5c1c | 698 | |
2bc0f45e JH |
699 | if (dkim->dkim_timestamps) |
700 | if (!(dkim_timestamps_expanded = expand_string(dkim->dkim_timestamps))) | |
701 | { errwhen = US"dkim_timestamps"; goto expand_bad; } | |
702 | else | |
703 | xval = (tval = (unsigned long) time(NULL)) | |
48334568 | 704 | + strtoul(CCS dkim_timestamps_expanded, NULL, 10); |
2bc0f45e | 705 | |
617d3932 | 706 | if (!(sig = pdkim_init_sign(&dkim_sign_ctx, dkim_signing_domain, |
9e70917d JH |
707 | dkim_signing_selector, |
708 | dkim_private_key_expanded, | |
709 | dkim_hash_expanded, | |
710 | errstr | |
711 | ))) | |
712 | goto bad; | |
713 | dkim_private_key_expanded[0] = '\0'; | |
714 | ||
715 | pdkim_set_optional(sig, | |
716 | CS dkim_sign_headers_expanded, | |
27fd1318 | 717 | CS dkim_identity_expanded, |
9e70917d | 718 | pdkim_canon, |
2bc0f45e | 719 | pdkim_canon, -1, tval, xval); |
9e70917d | 720 | |
617d3932 | 721 | if (!pdkim_set_sig_bodyhash(&dkim_sign_ctx, sig)) |
cf1cce5e JH |
722 | goto bad; |
723 | ||
617d3932 JH |
724 | if (!dkim_sign_ctx.sig) /* link sig to context chain */ |
725 | dkim_sign_ctx.sig = sig; | |
9e70917d JH |
726 | else |
727 | { | |
617d3932 | 728 | pdkim_signature * n = dkim_sign_ctx.sig; |
9e70917d JH |
729 | while (n->next) n = n->next; |
730 | n->next = sig; | |
731 | } | |
80a47a2c | 732 | } |
9e70917d | 733 | } |
617d3932 JH |
734 | |
735 | /* We may need to carry on with the data-feed even if there are no DKIM sigs to | |
736 | produce, if some other package (eg. ARC) is signing. */ | |
737 | ||
738 | if (!dkim_sign_ctx.sig && !dkim->force_bodyhash) | |
0b8f4f1a JH |
739 | { |
740 | DEBUG(D_transport) debug_printf("DKIM: no viable signatures to use\n"); | |
741 | sigbuf = string_get(1); /* return a zero-len string */ | |
0b8f4f1a | 742 | } |
9e70917d | 743 | else |
9e70917d | 744 | { |
617d3932 JH |
745 | if (prefix && (pdkim_rc = pdkim_feed(&dkim_sign_ctx, prefix, Ustrlen(prefix))) != PDKIM_OK) |
746 | goto pk_bad; | |
a8e1eeba | 747 | |
617d3932 JH |
748 | if (lseek(fd, off, SEEK_SET) < 0) |
749 | sread = -1; | |
750 | else | |
751 | while ((sread = read(fd, &buf, sizeof(buf))) > 0) | |
752 | if ((pdkim_rc = pdkim_feed(&dkim_sign_ctx, buf, sread)) != PDKIM_OK) | |
753 | goto pk_bad; | |
9e70917d | 754 | |
617d3932 JH |
755 | /* Handle failed read above. */ |
756 | if (sread == -1) | |
757 | { | |
758 | debug_printf("DKIM: Error reading -K file.\n"); | |
759 | save_errno = errno; | |
760 | goto bad; | |
761 | } | |
762 | ||
763 | /* Build string of headers, one per signature */ | |
9e70917d | 764 | |
617d3932 JH |
765 | if ((pdkim_rc = pdkim_feed_finish(&dkim_sign_ctx, &sig, errstr)) != PDKIM_OK) |
766 | goto pk_bad; | |
767 | ||
768 | if (!sig) | |
769 | { | |
770 | DEBUG(D_transport) debug_printf("DKIM: no signatures to use\n"); | |
771 | sigbuf = string_get(1); /* return a zero-len string */ | |
772 | } | |
773 | else for (sigbuf = NULL; sig; sig = sig->next) | |
774 | sigbuf = string_append(sigbuf, 2, US sig->signature_header, US"\r\n"); | |
775 | } | |
9e70917d | 776 | |
1cfe5c1c | 777 | CLEANUP: |
0b8f4f1a | 778 | (void) string_from_gstring(sigbuf); |
f7302073 JH |
779 | store_pool = old_pool; |
780 | errno = save_errno; | |
9e70917d | 781 | return sigbuf; |
f7302073 JH |
782 | |
783 | pk_bad: | |
784 | log_write(0, LOG_MAIN|LOG_PANIC, | |
785 | "DKIM: signing failed: %.100s", pdkim_errstr(pdkim_rc)); | |
786 | bad: | |
9e70917d | 787 | sigbuf = NULL; |
f7302073 | 788 | goto CLEANUP; |
7c6ec81b JH |
789 | |
790 | expand_bad: | |
791 | log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand %s: %s", | |
792 | errwhen, expand_string_message); | |
793 | goto bad; | |
93f2d376 | 794 | } |
80a47a2c | 795 | |
dfbcb5ac JH |
796 | |
797 | ||
798 | ||
799 | gstring * | |
800 | authres_dkim(gstring * g) | |
801 | { | |
802 | pdkim_signature * sig; | |
0ae2cff6 | 803 | int start = 0; /* compiler quietening */ |
617d3932 JH |
804 | |
805 | DEBUG(D_acl) start = g->ptr; | |
dfbcb5ac JH |
806 | |
807 | for (sig = dkim_signatures; sig; sig = sig->next) | |
808 | { | |
e34f8ca2 | 809 | g = string_catn(g, US";\n\tdkim=", 8); |
dfbcb5ac JH |
810 | |
811 | if (sig->verify_status & PDKIM_VERIFY_POLICY) | |
812 | g = string_append(g, 5, | |
813 | US"policy (", dkim_verify_status, US" - ", dkim_verify_reason, US")"); | |
814 | else switch(sig->verify_status) | |
815 | { | |
816 | case PDKIM_VERIFY_NONE: g = string_cat(g, US"none"); break; | |
817 | case PDKIM_VERIFY_INVALID: | |
818 | switch (sig->verify_ext_status) | |
819 | { | |
820 | case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: | |
617d3932 | 821 | g = string_cat(g, US"tmperror (pubkey unavailable)\n\t\t"); break; |
dfbcb5ac | 822 | case PDKIM_VERIFY_INVALID_BUFFER_SIZE: |
617d3932 | 823 | g = string_cat(g, US"permerror (overlong public key record)\n\t\t"); break; |
dfbcb5ac JH |
824 | case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: |
825 | case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: | |
0e8aed8a | 826 | g = string_cat(g, US"neutral (public key record import problem)\n\t\t"); |
dfbcb5ac JH |
827 | break; |
828 | case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: | |
617d3932 | 829 | g = string_cat(g, US"neutral (signature tag missing or invalid)\n\t\t"); |
dfbcb5ac JH |
830 | break; |
831 | case PDKIM_VERIFY_INVALID_DKIM_VERSION: | |
617d3932 | 832 | g = string_cat(g, US"neutral (unsupported DKIM version)\n\t\t"); |
dfbcb5ac JH |
833 | break; |
834 | default: | |
617d3932 | 835 | g = string_cat(g, US"permerror (unspecified problem)\n\t\t"); break; |
dfbcb5ac JH |
836 | } |
837 | break; | |
838 | case PDKIM_VERIFY_FAIL: | |
839 | switch (sig->verify_ext_status) | |
840 | { | |
841 | case PDKIM_VERIFY_FAIL_BODY: | |
842 | g = string_cat(g, | |
617d3932 | 843 | US"fail (body hash mismatch; body probably modified in transit)\n\t\t"); |
dfbcb5ac JH |
844 | break; |
845 | case PDKIM_VERIFY_FAIL_MESSAGE: | |
846 | g = string_cat(g, | |
617d3932 | 847 | US"fail (signature did not verify; headers probably modified in transit)\n\t\t"); |
dfbcb5ac JH |
848 | break; |
849 | default: | |
617d3932 | 850 | g = string_cat(g, US"fail (unspecified reason)\n\t\t"); |
dfbcb5ac JH |
851 | break; |
852 | } | |
853 | break; | |
854 | case PDKIM_VERIFY_PASS: g = string_cat(g, US"pass"); break; | |
855 | default: g = string_cat(g, US"permerror"); break; | |
856 | } | |
857 | if (sig->domain) g = string_append(g, 2, US" header.d=", sig->domain); | |
858 | if (sig->identity) g = string_append(g, 2, US" header.i=", sig->identity); | |
859 | if (sig->selector) g = string_append(g, 2, US" header.s=", sig->selector); | |
860 | g = string_append(g, 2, US" header.a=", dkim_sig_to_a_tag(sig)); | |
861 | } | |
617d3932 JH |
862 | |
863 | DEBUG(D_acl) | |
864 | if (g->ptr == start) | |
865 | debug_printf("DKIM: no authres\n"); | |
866 | else | |
867 | debug_printf("DKIM: authres '%.*s'\n", g->ptr - start - 3, g->s + start + 3); | |
dfbcb5ac JH |
868 | return g; |
869 | } | |
870 | ||
871 | ||
970424a5 JH |
872 | # endif /*!MACRO_PREDEF*/ |
873 | #endif /*!DISABLE_DKIM*/ |