Commit | Line | Data |
---|---|---|
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); | |
d34c22b8 | 24 | builtin_macro_create_var(US"_DKIM_OVERSIGN_HEADERS", US PDKIM_OVERSIGN_HEADERS); |
970424a5 JH |
25 | } |
26 | # else /*!MACRO_PREDEF*/ | |
27 | ||
28 | ||
29 | ||
617d3932 | 30 | pdkim_ctx dkim_sign_ctx; |
80a47a2c | 31 | |
ca9cb170 | 32 | int dkim_verify_oldpool; |
1cfe5c1c | 33 | pdkim_ctx *dkim_verify_ctx = NULL; |
1cfe5c1c | 34 | pdkim_signature *dkim_cur_sig = NULL; |
b9df1829 | 35 | static const uschar * dkim_collect_error = NULL; |
80a47a2c | 36 | |
64b67b65 JH |
37 | #define DKIM_MAX_SIGNATURES 20 |
38 | ||
d73e45df JH |
39 | |
40 | ||
362e4161 JH |
41 | /* Look up the DKIM record in DNS for the given hostname. |
42 | Will use the first found if there are multiple. | |
43 | The return string is tainted, having come from off-site. | |
d73e45df JH |
44 | */ |
45 | ||
617d3932 | 46 | uschar * |
fc2ba7b9 | 47 | dkim_exim_query_dns_txt(const uschar * name) |
1cfe5c1c | 48 | { |
8743d3ac | 49 | dns_answer * dnsa = store_get_dns_answer(); |
1cfe5c1c | 50 | dns_scan dnss; |
f3ebb786 | 51 | rmark reset_point = store_mark(); |
1eedc10f | 52 | gstring * g = NULL; |
80a47a2c | 53 | |
1cfe5c1c | 54 | lookup_dnssec_authenticated = NULL; |
362e4161 | 55 | if (dns_lookup(dnsa, name, T_TXT, NULL) != DNS_SUCCEED) |
1eedc10f | 56 | return NULL; /*XXX better error detail? logging? */ |
80a47a2c | 57 | |
1cfe5c1c | 58 | /* Search for TXT record */ |
80a47a2c | 59 | |
362e4161 | 60 | for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); |
1cfe5c1c | 61 | rr; |
362e4161 | 62 | rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) |
1cfe5c1c JH |
63 | if (rr->type == T_TXT) |
64 | { | |
80a47a2c | 65 | int rr_offset = 0; |
1cfe5c1c JH |
66 | |
67 | /* Copy record content to the answer buffer */ | |
68 | ||
69 | while (rr_offset < rr->size) | |
70 | { | |
71 | uschar len = rr->data[rr_offset++]; | |
1eedc10f JH |
72 | |
73 | g = string_catn(g, US(rr->data + rr_offset), len); | |
74 | if (g->ptr >= PDKIM_DNS_TXT_MAX_RECLEN) | |
75 | goto bad; | |
76 | ||
1cfe5c1c | 77 | rr_offset += len; |
4263f395 | 78 | } |
dd33c4e6 HSHR |
79 | |
80 | /* check if this looks like a DKIM record */ | |
d011368a | 81 | if (Ustrncmp(g->s, "v=", 2) != 0 || strncasecmp(CS g->s, "v=dkim", 6) == 0) |
1eedc10f | 82 | { |
e59797e3 | 83 | gstring_release_unused(g); |
1eedc10f JH |
84 | return string_from_gstring(g); |
85 | } | |
86 | ||
87 | if (g) g->ptr = 0; /* overwrite previous record */ | |
80a47a2c | 88 | } |
80a47a2c | 89 | |
1eedc10f | 90 | bad: |
f3ebb786 | 91 | store_reset(reset_point); |
1eedc10f | 92 | return NULL; /*XXX better error detail? logging? */ |
80a47a2c TK |
93 | } |
94 | ||
95 | ||
2592e6c0 JH |
96 | void |
97 | dkim_exim_init(void) | |
98 | { | |
d85cdeb5 JH |
99 | if (f.dkim_init_done) return; |
100 | f.dkim_init_done = TRUE; | |
2592e6c0 JH |
101 | pdkim_init(); |
102 | } | |
103 | ||
104 | ||
ca9cb170 | 105 | |
1cfe5c1c | 106 | void |
e983e85a | 107 | dkim_exim_verify_init(BOOL dot_stuffing) |
1cfe5c1c | 108 | { |
d85cdeb5 JH |
109 | dkim_exim_init(); |
110 | ||
ca9cb170 JH |
111 | /* There is a store-reset between header & body reception |
112 | so cannot use the main pool. Any allocs done by Exim | |
113 | memory-handling must use the perm pool. */ | |
114 | ||
115 | dkim_verify_oldpool = store_pool; | |
116 | store_pool = POOL_PERM; | |
117 | ||
1cfe5c1c | 118 | /* Free previous context if there is one */ |
80a47a2c | 119 | |
1cfe5c1c JH |
120 | if (dkim_verify_ctx) |
121 | pdkim_free_ctx(dkim_verify_ctx); | |
80a47a2c | 122 | |
1cfe5c1c | 123 | /* Create new context */ |
80a47a2c | 124 | |
e983e85a | 125 | dkim_verify_ctx = pdkim_init_verify(&dkim_exim_query_dns_txt, dot_stuffing); |
64b67b65 | 126 | dkim_collect_input = dkim_verify_ctx ? DKIM_MAX_SIGNATURES : 0; |
b9df1829 | 127 | dkim_collect_error = NULL; |
ca9cb170 | 128 | |
584e96c6 JH |
129 | /* Start feed up with any cached data */ |
130 | receive_get_cache(); | |
131 | ||
ca9cb170 | 132 | store_pool = dkim_verify_oldpool; |
80a47a2c TK |
133 | } |
134 | ||
135 | ||
1cfe5c1c JH |
136 | void |
137 | dkim_exim_verify_feed(uschar * data, int len) | |
138 | { | |
f7302073 JH |
139 | int rc; |
140 | ||
ca9cb170 | 141 | store_pool = POOL_PERM; |
1cfe5c1c | 142 | if ( dkim_collect_input |
ef698bf6 | 143 | && (rc = pdkim_feed(dkim_verify_ctx, data, len)) != PDKIM_OK) |
f7302073 | 144 | { |
b9df1829 | 145 | dkim_collect_error = pdkim_errstr(rc); |
f7302073 | 146 | log_write(0, LOG_MAIN, |
b9df1829 | 147 | "DKIM: validation error: %.100s", dkim_collect_error); |
64b67b65 | 148 | dkim_collect_input = 0; |
f7302073 | 149 | } |
ca9cb170 | 150 | store_pool = dkim_verify_oldpool; |
80a47a2c TK |
151 | } |
152 | ||
153 | ||
a79d8834 JH |
154 | /* Log the result for the given signature */ |
155 | static void | |
156 | dkim_exim_verify_log_sig(pdkim_signature * sig) | |
1cfe5c1c | 157 | { |
cc55f420 | 158 | gstring * logmsg; |
a79d8834 JH |
159 | uschar * s; |
160 | ||
cc55f420 JH |
161 | if (!sig) return; |
162 | ||
6678c382 | 163 | /* Remember the domain for the first pass result */ |
dfbcb5ac | 164 | |
2c47372f JH |
165 | if ( !dkim_verify_overall |
166 | && dkim_verify_status | |
167 | ? Ustrcmp(dkim_verify_status, US"pass") == 0 | |
168 | : sig->verify_status == PDKIM_VERIFY_PASS | |
169 | ) | |
170 | dkim_verify_overall = string_copy(sig->domain); | |
171 | ||
6678c382 JH |
172 | /* Rewrite the sig result if the ACL overrode it. This is only |
173 | needed because the DMARC code (sigh) peeks at the dkim sigs. | |
174 | Mark the sig for this having been done. */ | |
175 | ||
176 | if ( dkim_verify_status | |
177 | && ( dkim_verify_status != dkim_exim_expand_query(DKIM_VERIFY_STATUS) | |
178 | || dkim_verify_reason != dkim_exim_expand_query(DKIM_VERIFY_REASON) | |
179 | ) ) | |
180 | { /* overridden by ACL */ | |
181 | sig->verify_ext_status = -1; | |
182 | if (Ustrcmp(dkim_verify_status, US"fail") == 0) | |
183 | sig->verify_status = PDKIM_VERIFY_POLICY | PDKIM_VERIFY_FAIL; | |
184 | else if (Ustrcmp(dkim_verify_status, US"invalid") == 0) | |
185 | sig->verify_status = PDKIM_VERIFY_POLICY | PDKIM_VERIFY_INVALID; | |
186 | else if (Ustrcmp(dkim_verify_status, US"none") == 0) | |
187 | sig->verify_status = PDKIM_VERIFY_POLICY | PDKIM_VERIFY_NONE; | |
188 | else if (Ustrcmp(dkim_verify_status, US"pass") == 0) | |
189 | sig->verify_status = PDKIM_VERIFY_POLICY | PDKIM_VERIFY_PASS; | |
190 | else | |
191 | sig->verify_status = -1; | |
192 | } | |
193 | ||
2c47372f JH |
194 | if (!LOGGING(dkim_verbose)) return; |
195 | ||
6678c382 | 196 | |
aaaa94ea | 197 | logmsg = string_catn(NULL, US"DKIM: ", 6); |
a79d8834 JH |
198 | if (!(s = sig->domain)) s = US"<UNSET>"; |
199 | logmsg = string_append(logmsg, 2, "d=", s); | |
200 | if (!(s = sig->selector)) s = US"<UNSET>"; | |
201 | logmsg = string_append(logmsg, 2, " s=", s); | |
52f12a7c JH |
202 | logmsg = string_fmt_append(logmsg, " c=%s/%s a=%s b=" SIZE_T_FMT, |
203 | sig->canon_headers == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", | |
204 | sig->canon_body == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", | |
205 | dkim_sig_to_a_tag(sig), | |
206 | (int)sig->sighash.len > -1 ? sig->sighash.len * 8 : (size_t)0); | |
a79d8834 | 207 | if ((s= sig->identity)) logmsg = string_append(logmsg, 2, " i=", s); |
52f12a7c JH |
208 | if (sig->created > 0) logmsg = string_fmt_append(logmsg, " t=%lu", |
209 | sig->created); | |
210 | if (sig->expires > 0) logmsg = string_fmt_append(logmsg, " x=%lu", | |
211 | sig->expires); | |
212 | if (sig->bodylength > -1) logmsg = string_fmt_append(logmsg, " l=%lu", | |
213 | sig->bodylength); | |
a79d8834 | 214 | |
dfbcb5ac JH |
215 | if (sig->verify_status & PDKIM_VERIFY_POLICY) |
216 | logmsg = string_append(logmsg, 5, | |
217 | US" [", dkim_verify_status, US" - ", dkim_verify_reason, US"]"); | |
218 | else | |
1cfe5c1c JH |
219 | switch (sig->verify_status) |
220 | { | |
221 | case PDKIM_VERIFY_NONE: | |
aaaa94ea | 222 | logmsg = string_cat(logmsg, US" [not verified]"); |
80a47a2c | 223 | break; |
1cfe5c1c JH |
224 | |
225 | case PDKIM_VERIFY_INVALID: | |
aaaa94ea | 226 | logmsg = string_cat(logmsg, US" [invalid - "); |
1cfe5c1c JH |
227 | switch (sig->verify_ext_status) |
228 | { | |
229 | case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: | |
acec9514 | 230 | logmsg = string_cat(logmsg, |
aaaa94ea | 231 | US"public key record (currently?) unavailable]"); |
1cfe5c1c JH |
232 | break; |
233 | ||
234 | case PDKIM_VERIFY_INVALID_BUFFER_SIZE: | |
aaaa94ea | 235 | logmsg = string_cat(logmsg, US"overlong public key record]"); |
1cfe5c1c JH |
236 | break; |
237 | ||
df3def24 JH |
238 | case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: |
239 | case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: | |
aaaa94ea | 240 | logmsg = string_cat(logmsg, US"syntax error in public key record]"); |
1cfe5c1c | 241 | break; |
07eeb4df | 242 | |
a79d8834 | 243 | case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: |
aaaa94ea | 244 | logmsg = string_cat(logmsg, US"signature tag missing or invalid]"); |
a79d8834 | 245 | break; |
07eeb4df | 246 | |
a79d8834 | 247 | case PDKIM_VERIFY_INVALID_DKIM_VERSION: |
aaaa94ea | 248 | logmsg = string_cat(logmsg, US"unsupported DKIM version]"); |
a79d8834 | 249 | break; |
1cfe5c1c JH |
250 | |
251 | default: | |
aaaa94ea | 252 | logmsg = string_cat(logmsg, US"unspecified problem]"); |
1cfe5c1c | 253 | } |
80a47a2c | 254 | break; |
1cfe5c1c JH |
255 | |
256 | case PDKIM_VERIFY_FAIL: | |
aaaa94ea | 257 | logmsg = string_cat(logmsg, US" [verification failed - "); |
1cfe5c1c JH |
258 | switch (sig->verify_ext_status) |
259 | { | |
260 | case PDKIM_VERIFY_FAIL_BODY: | |
acec9514 | 261 | logmsg = string_cat(logmsg, |
aaaa94ea | 262 | US"body hash mismatch (body probably modified in transit)]"); |
1cfe5c1c JH |
263 | break; |
264 | ||
265 | case PDKIM_VERIFY_FAIL_MESSAGE: | |
acec9514 | 266 | logmsg = string_cat(logmsg, |
aaaa94ea JH |
267 | US"signature did not verify " |
268 | "(headers probably modified in transit)]"); | |
dfbcb5ac | 269 | break; |
1cfe5c1c JH |
270 | |
271 | default: | |
aaaa94ea | 272 | logmsg = string_cat(logmsg, US"unspecified reason]"); |
1cfe5c1c | 273 | } |
80a47a2c | 274 | break; |
1cfe5c1c JH |
275 | |
276 | case PDKIM_VERIFY_PASS: | |
aaaa94ea | 277 | logmsg = string_cat(logmsg, US" [verification succeeded]"); |
80a47a2c TK |
278 | break; |
279 | } | |
a79d8834 | 280 | |
aaaa94ea | 281 | log_write(0, LOG_MAIN, "%s", string_from_gstring(logmsg)); |
a79d8834 JH |
282 | return; |
283 | } | |
284 | ||
80a47a2c | 285 | |
a79d8834 JH |
286 | /* Log a line for each signature */ |
287 | void | |
288 | dkim_exim_verify_log_all(void) | |
289 | { | |
d7978c0f JH |
290 | for (pdkim_signature * sig = dkim_signatures; sig; sig = sig->next) |
291 | dkim_exim_verify_log_sig(sig); | |
a79d8834 | 292 | } |
1cfe5c1c | 293 | |
80a47a2c | 294 | |
a79d8834 JH |
295 | void |
296 | dkim_exim_verify_finish(void) | |
297 | { | |
a79d8834 JH |
298 | int rc; |
299 | gstring * g = NULL; | |
286b9d5f | 300 | const uschar * errstr = NULL; |
a79d8834 JH |
301 | |
302 | store_pool = POOL_PERM; | |
303 | ||
304 | /* Delete eventual previous signature chain */ | |
305 | ||
306 | dkim_signers = NULL; | |
307 | dkim_signatures = NULL; | |
308 | ||
309 | if (dkim_collect_error) | |
310 | { | |
311 | log_write(0, LOG_MAIN, | |
312 | "DKIM: Error during validation, disabling signature verification: %.100s", | |
313 | dkim_collect_error); | |
8768d548 | 314 | f.dkim_disable_verify = TRUE; |
a79d8834 JH |
315 | goto out; |
316 | } | |
317 | ||
64b67b65 | 318 | dkim_collect_input = 0; |
a79d8834 JH |
319 | |
320 | /* Finish DKIM operation and fetch link to signatures chain */ | |
321 | ||
b4757e36 JH |
322 | rc = pdkim_feed_finish(dkim_verify_ctx, (pdkim_signature **)&dkim_signatures, |
323 | &errstr); | |
286b9d5f JH |
324 | if (rc != PDKIM_OK && errstr) |
325 | log_write(0, LOG_MAIN, "DKIM: validation error: %s", errstr); | |
a79d8834 JH |
326 | |
327 | /* Build a colon-separated list of signing domains (and identities, if present) in dkim_signers */ | |
328 | ||
d7978c0f | 329 | for (pdkim_signature * sig = dkim_signatures; sig; sig = sig->next) |
a79d8834 JH |
330 | { |
331 | if (sig->domain) g = string_append_listele(g, ':', sig->domain); | |
332 | if (sig->identity) g = string_append_listele(g, ':', sig->identity); | |
80a47a2c TK |
333 | } |
334 | ||
acec9514 JH |
335 | if (g) dkim_signers = g->s; |
336 | ||
ca9cb170 JH |
337 | out: |
338 | store_pool = dkim_verify_oldpool; | |
80a47a2c TK |
339 | } |
340 | ||
341 | ||
18067c75 JH |
342 | |
343 | /* Args as per dkim_exim_acl_run() below */ | |
344 | static int | |
345 | dkim_acl_call(uschar * id, gstring ** res_ptr, | |
346 | uschar ** user_msgptr, uschar ** log_msgptr) | |
347 | { | |
348 | int rc; | |
349 | DEBUG(D_receive) | |
350 | debug_printf("calling acl_smtp_dkim for dkim_cur_signer='%s'\n", id); | |
351 | ||
352 | rc = acl_check(ACL_WHERE_DKIM, NULL, acl_smtp_dkim, user_msgptr, log_msgptr); | |
353 | dkim_exim_verify_log_sig(dkim_cur_sig); | |
354 | *res_ptr = string_append_listele(*res_ptr, ':', dkim_verify_status); | |
355 | return rc; | |
356 | } | |
357 | ||
358 | ||
359 | ||
360 | /* For the given identity, run the DKIM ACL once for each matching signature. | |
361 | ||
362 | Arguments | |
363 | id Identity to look for in dkim signatures | |
364 | res_ptr ptr to growable string-list of status results, | |
365 | appended to per ACL run | |
366 | user_msgptr where to put a user error (for SMTP response) | |
367 | log_msgptr where to put a logging message (not for SMTP response) | |
368 | ||
369 | Returns: OK access is granted by an ACCEPT verb | |
370 | DISCARD access is granted by a DISCARD verb | |
371 | FAIL access is denied | |
372 | FAIL_DROP access is denied; drop the connection | |
373 | DEFER can't tell at the moment | |
374 | ERROR disaster | |
375 | */ | |
376 | ||
377 | int | |
378 | dkim_exim_acl_run(uschar * id, gstring ** res_ptr, | |
379 | uschar ** user_msgptr, uschar ** log_msgptr) | |
1cfe5c1c | 380 | { |
1cfe5c1c | 381 | uschar * cmp_val; |
18067c75 | 382 | int rc = -1; |
1cfe5c1c | 383 | |
cc55f420 JH |
384 | dkim_verify_status = US"none"; |
385 | dkim_verify_reason = US""; | |
1cfe5c1c JH |
386 | dkim_cur_signer = id; |
387 | ||
8768d548 | 388 | if (f.dkim_disable_verify || !id || !dkim_verify_ctx) |
18067c75 | 389 | return OK; |
1cfe5c1c | 390 | |
18067c75 | 391 | /* Find signatures to run ACL on */ |
1cfe5c1c | 392 | |
d7978c0f | 393 | for (pdkim_signature * sig = dkim_signatures; sig; sig = sig->next) |
1cfe5c1c JH |
394 | if ( (cmp_val = Ustrchr(id, '@') != NULL ? US sig->identity : US sig->domain) |
395 | && strcmpic(cmp_val, id) == 0 | |
396 | ) | |
397 | { | |
1cfe5c1c | 398 | /* The "dkim_domain" and "dkim_selector" expansion variables have |
18067c75 JH |
399 | related globals, since they are used in the signing code too. |
400 | Instead of inventing separate names for verification, we set | |
401 | them here. This is easy since a domain and selector is guaranteed | |
402 | to be in a signature. The other dkim_* expansion items are | |
403 | dynamically fetched from dkim_cur_sig at expansion time (see | |
b4757e36 | 404 | dkim_exim_expand_query() below). */ |
1cfe5c1c | 405 | |
18067c75 | 406 | dkim_cur_sig = sig; |
1cfe5c1c JH |
407 | dkim_signing_domain = US sig->domain; |
408 | dkim_signing_selector = US sig->selector; | |
dcd03763 | 409 | dkim_key_length = sig->sighash.len * 8; |
a79d8834 JH |
410 | |
411 | /* These two return static strings, so we can compare the addr | |
412 | later to see if the ACL overwrote them. Check that when logging */ | |
413 | ||
414 | dkim_verify_status = dkim_exim_expand_query(DKIM_VERIFY_STATUS); | |
415 | dkim_verify_reason = dkim_exim_expand_query(DKIM_VERIFY_REASON); | |
dd33c4e6 | 416 | |
18067c75 JH |
417 | if ((rc = dkim_acl_call(id, res_ptr, user_msgptr, log_msgptr)) != OK) |
418 | return rc; | |
80a47a2c | 419 | } |
18067c75 JH |
420 | |
421 | if (rc != -1) | |
422 | return rc; | |
423 | ||
424 | /* No matching sig found. Call ACL once anyway. */ | |
425 | ||
426 | dkim_cur_sig = NULL; | |
427 | return dkim_acl_call(id, res_ptr, user_msgptr, log_msgptr); | |
80a47a2c TK |
428 | } |
429 | ||
430 | ||
1cfe5c1c JH |
431 | static uschar * |
432 | dkim_exim_expand_defaults(int what) | |
433 | { | |
434 | switch (what) | |
435 | { | |
436 | case DKIM_ALGO: return US""; | |
437 | case DKIM_BODYLENGTH: return US"9999999999999"; | |
438 | case DKIM_CANON_BODY: return US""; | |
439 | case DKIM_CANON_HEADERS: return US""; | |
440 | case DKIM_COPIEDHEADERS: return US""; | |
441 | case DKIM_CREATED: return US"0"; | |
442 | case DKIM_EXPIRES: return US"9999999999999"; | |
443 | case DKIM_HEADERNAMES: return US""; | |
444 | case DKIM_IDENTITY: return US""; | |
445 | case DKIM_KEY_GRANULARITY: return US"*"; | |
446 | case DKIM_KEY_SRVTYPE: return US"*"; | |
447 | case DKIM_KEY_NOTES: return US""; | |
448 | case DKIM_KEY_TESTING: return US"0"; | |
449 | case DKIM_NOSUBDOMAINS: return US"0"; | |
450 | case DKIM_VERIFY_STATUS: return US"none"; | |
451 | case DKIM_VERIFY_REASON: return US""; | |
452 | default: return US""; | |
453 | } | |
454 | } | |
80a47a2c | 455 | |
80a47a2c | 456 | |
1cfe5c1c JH |
457 | uschar * |
458 | dkim_exim_expand_query(int what) | |
459 | { | |
8768d548 | 460 | if (!dkim_verify_ctx || f.dkim_disable_verify || !dkim_cur_sig) |
1cfe5c1c JH |
461 | return dkim_exim_expand_defaults(what); |
462 | ||
463 | switch (what) | |
464 | { | |
465 | case DKIM_ALGO: | |
d73e45df | 466 | return dkim_sig_to_a_tag(dkim_cur_sig); |
1cfe5c1c JH |
467 | |
468 | case DKIM_BODYLENGTH: | |
469 | return dkim_cur_sig->bodylength >= 0 | |
bb07bcd3 | 470 | ? string_sprintf("%ld", dkim_cur_sig->bodylength) |
1cfe5c1c JH |
471 | : dkim_exim_expand_defaults(what); |
472 | ||
473 | case DKIM_CANON_BODY: | |
474 | switch (dkim_cur_sig->canon_body) | |
475 | { | |
476 | case PDKIM_CANON_RELAXED: return US"relaxed"; | |
477 | case PDKIM_CANON_SIMPLE: | |
478 | default: return US"simple"; | |
80a47a2c | 479 | } |
1cfe5c1c JH |
480 | |
481 | case DKIM_CANON_HEADERS: | |
a79d8834 JH |
482 | switch (dkim_cur_sig->canon_headers) |
483 | { | |
484 | case PDKIM_CANON_RELAXED: return US"relaxed"; | |
485 | case PDKIM_CANON_SIMPLE: | |
486 | default: return US"simple"; | |
487 | } | |
1cfe5c1c JH |
488 | |
489 | case DKIM_COPIEDHEADERS: | |
490 | return dkim_cur_sig->copiedheaders | |
491 | ? US dkim_cur_sig->copiedheaders : dkim_exim_expand_defaults(what); | |
492 | ||
493 | case DKIM_CREATED: | |
494 | return dkim_cur_sig->created > 0 | |
bb07bcd3 | 495 | ? string_sprintf("%lu", dkim_cur_sig->created) |
1cfe5c1c JH |
496 | : dkim_exim_expand_defaults(what); |
497 | ||
498 | case DKIM_EXPIRES: | |
499 | return dkim_cur_sig->expires > 0 | |
bb07bcd3 | 500 | ? string_sprintf("%lu", dkim_cur_sig->expires) |
1cfe5c1c JH |
501 | : dkim_exim_expand_defaults(what); |
502 | ||
503 | case DKIM_HEADERNAMES: | |
504 | return dkim_cur_sig->headernames | |
2592e6c0 | 505 | ? dkim_cur_sig->headernames : dkim_exim_expand_defaults(what); |
1cfe5c1c JH |
506 | |
507 | case DKIM_IDENTITY: | |
508 | return dkim_cur_sig->identity | |
509 | ? US dkim_cur_sig->identity : dkim_exim_expand_defaults(what); | |
510 | ||
511 | case DKIM_KEY_GRANULARITY: | |
512 | return dkim_cur_sig->pubkey | |
513 | ? dkim_cur_sig->pubkey->granularity | |
514 | ? US dkim_cur_sig->pubkey->granularity | |
515 | : dkim_exim_expand_defaults(what) | |
516 | : dkim_exim_expand_defaults(what); | |
517 | ||
518 | case DKIM_KEY_SRVTYPE: | |
519 | return dkim_cur_sig->pubkey | |
520 | ? dkim_cur_sig->pubkey->srvtype | |
521 | ? US dkim_cur_sig->pubkey->srvtype | |
522 | : dkim_exim_expand_defaults(what) | |
523 | : dkim_exim_expand_defaults(what); | |
524 | ||
525 | case DKIM_KEY_NOTES: | |
526 | return dkim_cur_sig->pubkey | |
527 | ? dkim_cur_sig->pubkey->notes | |
528 | ? US dkim_cur_sig->pubkey->notes | |
529 | : dkim_exim_expand_defaults(what) | |
530 | : dkim_exim_expand_defaults(what); | |
531 | ||
532 | case DKIM_KEY_TESTING: | |
533 | return dkim_cur_sig->pubkey | |
534 | ? dkim_cur_sig->pubkey->testing | |
535 | ? US"1" | |
536 | : dkim_exim_expand_defaults(what) | |
537 | : dkim_exim_expand_defaults(what); | |
538 | ||
539 | case DKIM_NOSUBDOMAINS: | |
540 | return dkim_cur_sig->pubkey | |
541 | ? dkim_cur_sig->pubkey->no_subdomaining | |
542 | ? US"1" | |
543 | : dkim_exim_expand_defaults(what) | |
544 | : dkim_exim_expand_defaults(what); | |
545 | ||
546 | case DKIM_VERIFY_STATUS: | |
547 | switch (dkim_cur_sig->verify_status) | |
548 | { | |
549 | case PDKIM_VERIFY_INVALID: return US"invalid"; | |
550 | case PDKIM_VERIFY_FAIL: return US"fail"; | |
551 | case PDKIM_VERIFY_PASS: return US"pass"; | |
552 | case PDKIM_VERIFY_NONE: | |
553 | default: return US"none"; | |
80a47a2c | 554 | } |
80a47a2c | 555 | |
1cfe5c1c JH |
556 | case DKIM_VERIFY_REASON: |
557 | switch (dkim_cur_sig->verify_ext_status) | |
558 | { | |
559 | case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: | |
560 | return US"pubkey_unavailable"; | |
df3def24 JH |
561 | case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD:return US"pubkey_dns_syntax"; |
562 | case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: return US"pubkey_der_syntax"; | |
1cfe5c1c JH |
563 | case PDKIM_VERIFY_FAIL_BODY: return US"bodyhash_mismatch"; |
564 | case PDKIM_VERIFY_FAIL_MESSAGE: return US"signature_incorrect"; | |
565 | } | |
80a47a2c | 566 | |
1cfe5c1c JH |
567 | default: |
568 | return US""; | |
80a47a2c TK |
569 | } |
570 | } | |
571 | ||
572 | ||
617d3932 JH |
573 | void |
574 | dkim_exim_sign_init(void) | |
575 | { | |
576 | int old_pool = store_pool; | |
d85cdeb5 JH |
577 | |
578 | dkim_exim_init(); | |
617d3932 JH |
579 | store_pool = POOL_MAIN; |
580 | pdkim_init_context(&dkim_sign_ctx, FALSE, &dkim_exim_query_dns_txt); | |
581 | store_pool = old_pool; | |
582 | } | |
583 | ||
584 | ||
0b8f4f1a | 585 | /* Generate signatures for the given file. |
42055a33 | 586 | If a prefix is given, prepend it to the file for the calculations. |
0b8f4f1a JH |
587 | |
588 | Return: | |
589 | NULL: error; error string written | |
590 | string: signature header(s), or a zero-length string (not an error) | |
42055a33 JH |
591 | */ |
592 | ||
acec9514 | 593 | gstring * |
42055a33 JH |
594 | dkim_exim_sign(int fd, off_t off, uschar * prefix, |
595 | struct ob_dkim * dkim, const uschar ** errstr) | |
55414b25 | 596 | { |
617d3932 | 597 | const uschar * dkim_domain = NULL; |
1cfe5c1c | 598 | int sep = 0; |
acec9514 | 599 | gstring * seen_doms = NULL; |
9e70917d | 600 | pdkim_signature * sig; |
acec9514 | 601 | gstring * sigbuf; |
1cfe5c1c JH |
602 | int pdkim_rc; |
603 | int sread; | |
ef698bf6 | 604 | uschar buf[4096]; |
1cfe5c1c JH |
605 | int save_errno = 0; |
606 | int old_pool = store_pool; | |
7c6ec81b | 607 | uschar * errwhen; |
617d3932 | 608 | const uschar * s; |
1cfe5c1c | 609 | |
617d3932 JH |
610 | if (dkim->dot_stuffed) |
611 | dkim_sign_ctx.flags |= PDKIM_DOT_TERM; | |
1cfe5c1c | 612 | |
617d3932 | 613 | store_pool = POOL_MAIN; |
9e70917d | 614 | |
617d3932 | 615 | if ((s = dkim->dkim_domain) && !(dkim_domain = expand_cstring(s))) |
1cfe5c1c | 616 | /* expansion error, do not send message. */ |
7c6ec81b | 617 | { errwhen = US"dkim_domain"; goto expand_bad; } |
1cfe5c1c JH |
618 | |
619 | /* Set $dkim_domain expansion variable to each unique domain in list. */ | |
620 | ||
617d3932 JH |
621 | if (dkim_domain) |
622 | while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, NULL, 0))) | |
1cfe5c1c | 623 | { |
9e70917d JH |
624 | const uschar * dkim_sel; |
625 | int sel_sep = 0; | |
626 | ||
42055a33 | 627 | if (dkim_signing_domain[0] == '\0') |
1cfe5c1c JH |
628 | continue; |
629 | ||
630 | /* Only sign once for each domain, no matter how often it | |
631 | appears in the expanded list. */ | |
632 | ||
fe12ec88 | 633 | dkim_signing_domain = string_copylc(dkim_signing_domain); |
9e70917d JH |
634 | if (match_isinlist(dkim_signing_domain, CUSS &seen_doms, |
635 | 0, NULL, NULL, MCL_STRING, TRUE, NULL) == OK) | |
636 | continue; | |
1cfe5c1c | 637 | |
acec9514 | 638 | seen_doms = string_append_listele(seen_doms, ':', dkim_signing_domain); |
1cfe5c1c | 639 | |
9e70917d JH |
640 | /* Set $dkim_selector expansion variable to each selector in list, |
641 | for this domain. */ | |
1cfe5c1c | 642 | |
9e70917d | 643 | if (!(dkim_sel = expand_string(dkim->dkim_selector))) |
7c6ec81b | 644 | { errwhen = US"dkim_selector"; goto expand_bad; } |
1cfe5c1c | 645 | |
9e70917d JH |
646 | while ((dkim_signing_selector = string_nextinlist(&dkim_sel, &sel_sep, |
647 | NULL, 0))) | |
1cfe5c1c | 648 | { |
9e70917d JH |
649 | uschar * dkim_canon_expanded; |
650 | int pdkim_canon; | |
651 | uschar * dkim_sign_headers_expanded = NULL; | |
652 | uschar * dkim_private_key_expanded; | |
653 | uschar * dkim_hash_expanded; | |
7c6ec81b | 654 | uschar * dkim_identity_expanded = NULL; |
2bc0f45e JH |
655 | uschar * dkim_timestamps_expanded = NULL; |
656 | unsigned long tval = 0, xval = 0; | |
80a47a2c | 657 | |
9e70917d | 658 | /* Get canonicalization to use */ |
1cfe5c1c | 659 | |
9e70917d JH |
660 | dkim_canon_expanded = dkim->dkim_canon |
661 | ? expand_string(dkim->dkim_canon) : US"relaxed"; | |
7c6ec81b JH |
662 | if (!dkim_canon_expanded) /* expansion error, do not send message. */ |
663 | { errwhen = US"dkim_canon"; goto expand_bad; } | |
1cfe5c1c | 664 | |
9e70917d JH |
665 | if (Ustrcmp(dkim_canon_expanded, "relaxed") == 0) |
666 | pdkim_canon = PDKIM_CANON_RELAXED; | |
667 | else if (Ustrcmp(dkim_canon_expanded, "simple") == 0) | |
668 | pdkim_canon = PDKIM_CANON_SIMPLE; | |
669 | else | |
670 | { | |
671 | log_write(0, LOG_MAIN, | |
672 | "DKIM: unknown canonicalization method '%s', defaulting to 'relaxed'.\n", | |
673 | dkim_canon_expanded); | |
674 | pdkim_canon = PDKIM_CANON_RELAXED; | |
675 | } | |
1cfe5c1c | 676 | |
7c6ec81b JH |
677 | if ( dkim->dkim_sign_headers |
678 | && !(dkim_sign_headers_expanded = expand_string(dkim->dkim_sign_headers))) | |
679 | { errwhen = US"dkim_sign_header"; goto expand_bad; } | |
680 | /* else pass NULL, which means default header list */ | |
1cfe5c1c | 681 | |
9e70917d | 682 | /* Get private key to use. */ |
e983e85a | 683 | |
9e70917d | 684 | if (!(dkim_private_key_expanded = expand_string(dkim->dkim_private_key))) |
7c6ec81b | 685 | { errwhen = US"dkim_private_key"; goto expand_bad; } |
80a47a2c | 686 | |
9e70917d JH |
687 | if ( Ustrlen(dkim_private_key_expanded) == 0 |
688 | || Ustrcmp(dkim_private_key_expanded, "0") == 0 | |
689 | || Ustrcmp(dkim_private_key_expanded, "false") == 0 | |
690 | ) | |
691 | continue; /* don't sign, but no error */ | |
692 | ||
617d3932 JH |
693 | if ( dkim_private_key_expanded[0] == '/' |
694 | && !(dkim_private_key_expanded = | |
695 | expand_file_big_buffer(dkim_private_key_expanded))) | |
696 | goto bad; | |
80a47a2c | 697 | |
9e70917d | 698 | if (!(dkim_hash_expanded = expand_string(dkim->dkim_hash))) |
7c6ec81b JH |
699 | { errwhen = US"dkim_hash"; goto expand_bad; } |
700 | ||
701 | if (dkim->dkim_identity) | |
702 | if (!(dkim_identity_expanded = expand_string(dkim->dkim_identity))) | |
703 | { errwhen = US"dkim_identity"; goto expand_bad; } | |
704 | else if (!*dkim_identity_expanded) | |
705 | dkim_identity_expanded = NULL; | |
1cfe5c1c | 706 | |
2bc0f45e JH |
707 | if (dkim->dkim_timestamps) |
708 | if (!(dkim_timestamps_expanded = expand_string(dkim->dkim_timestamps))) | |
709 | { errwhen = US"dkim_timestamps"; goto expand_bad; } | |
710 | else | |
711 | xval = (tval = (unsigned long) time(NULL)) | |
48334568 | 712 | + strtoul(CCS dkim_timestamps_expanded, NULL, 10); |
2bc0f45e | 713 | |
617d3932 | 714 | if (!(sig = pdkim_init_sign(&dkim_sign_ctx, dkim_signing_domain, |
9e70917d JH |
715 | dkim_signing_selector, |
716 | dkim_private_key_expanded, | |
717 | dkim_hash_expanded, | |
718 | errstr | |
719 | ))) | |
720 | goto bad; | |
721 | dkim_private_key_expanded[0] = '\0'; | |
722 | ||
723 | pdkim_set_optional(sig, | |
724 | CS dkim_sign_headers_expanded, | |
27fd1318 | 725 | CS dkim_identity_expanded, |
9e70917d | 726 | pdkim_canon, |
2bc0f45e | 727 | pdkim_canon, -1, tval, xval); |
9e70917d | 728 | |
617d3932 | 729 | if (!pdkim_set_sig_bodyhash(&dkim_sign_ctx, sig)) |
cf1cce5e JH |
730 | goto bad; |
731 | ||
617d3932 JH |
732 | if (!dkim_sign_ctx.sig) /* link sig to context chain */ |
733 | dkim_sign_ctx.sig = sig; | |
9e70917d JH |
734 | else |
735 | { | |
617d3932 | 736 | pdkim_signature * n = dkim_sign_ctx.sig; |
9e70917d JH |
737 | while (n->next) n = n->next; |
738 | n->next = sig; | |
739 | } | |
80a47a2c | 740 | } |
9e70917d | 741 | } |
617d3932 JH |
742 | |
743 | /* We may need to carry on with the data-feed even if there are no DKIM sigs to | |
744 | produce, if some other package (eg. ARC) is signing. */ | |
745 | ||
746 | if (!dkim_sign_ctx.sig && !dkim->force_bodyhash) | |
0b8f4f1a JH |
747 | { |
748 | DEBUG(D_transport) debug_printf("DKIM: no viable signatures to use\n"); | |
749 | sigbuf = string_get(1); /* return a zero-len string */ | |
0b8f4f1a | 750 | } |
9e70917d | 751 | else |
9e70917d | 752 | { |
617d3932 JH |
753 | if (prefix && (pdkim_rc = pdkim_feed(&dkim_sign_ctx, prefix, Ustrlen(prefix))) != PDKIM_OK) |
754 | goto pk_bad; | |
a8e1eeba | 755 | |
617d3932 JH |
756 | if (lseek(fd, off, SEEK_SET) < 0) |
757 | sread = -1; | |
758 | else | |
759 | while ((sread = read(fd, &buf, sizeof(buf))) > 0) | |
760 | if ((pdkim_rc = pdkim_feed(&dkim_sign_ctx, buf, sread)) != PDKIM_OK) | |
761 | goto pk_bad; | |
9e70917d | 762 | |
617d3932 JH |
763 | /* Handle failed read above. */ |
764 | if (sread == -1) | |
765 | { | |
766 | debug_printf("DKIM: Error reading -K file.\n"); | |
767 | save_errno = errno; | |
768 | goto bad; | |
769 | } | |
770 | ||
771 | /* Build string of headers, one per signature */ | |
9e70917d | 772 | |
617d3932 JH |
773 | if ((pdkim_rc = pdkim_feed_finish(&dkim_sign_ctx, &sig, errstr)) != PDKIM_OK) |
774 | goto pk_bad; | |
775 | ||
776 | if (!sig) | |
777 | { | |
778 | DEBUG(D_transport) debug_printf("DKIM: no signatures to use\n"); | |
779 | sigbuf = string_get(1); /* return a zero-len string */ | |
780 | } | |
781 | else for (sigbuf = NULL; sig; sig = sig->next) | |
782 | sigbuf = string_append(sigbuf, 2, US sig->signature_header, US"\r\n"); | |
783 | } | |
9e70917d | 784 | |
1cfe5c1c | 785 | CLEANUP: |
0b8f4f1a | 786 | (void) string_from_gstring(sigbuf); |
f7302073 JH |
787 | store_pool = old_pool; |
788 | errno = save_errno; | |
9e70917d | 789 | return sigbuf; |
f7302073 JH |
790 | |
791 | pk_bad: | |
792 | log_write(0, LOG_MAIN|LOG_PANIC, | |
9fa4d5b4 | 793 | "DKIM: signing failed: %.100s", pdkim_errstr(pdkim_rc)); |
f7302073 | 794 | bad: |
9e70917d | 795 | sigbuf = NULL; |
f7302073 | 796 | goto CLEANUP; |
7c6ec81b JH |
797 | |
798 | expand_bad: | |
9fa4d5b4 RJ |
799 | *errstr = string_sprintf("failed to expand %s: %s", |
800 | errwhen, expand_string_message); | |
801 | log_write(0, LOG_MAIN | LOG_PANIC, "%s", *errstr); | |
7c6ec81b | 802 | goto bad; |
93f2d376 | 803 | } |
80a47a2c | 804 | |
dfbcb5ac JH |
805 | |
806 | ||
807 | ||
808 | gstring * | |
809 | authres_dkim(gstring * g) | |
810 | { | |
0ae2cff6 | 811 | int start = 0; /* compiler quietening */ |
617d3932 JH |
812 | |
813 | DEBUG(D_acl) start = g->ptr; | |
dfbcb5ac | 814 | |
d7978c0f | 815 | for (pdkim_signature * sig = dkim_signatures; sig; sig = sig->next) |
dfbcb5ac | 816 | { |
e34f8ca2 | 817 | g = string_catn(g, US";\n\tdkim=", 8); |
dfbcb5ac JH |
818 | |
819 | if (sig->verify_status & PDKIM_VERIFY_POLICY) | |
820 | g = string_append(g, 5, | |
821 | US"policy (", dkim_verify_status, US" - ", dkim_verify_reason, US")"); | |
822 | else switch(sig->verify_status) | |
823 | { | |
824 | case PDKIM_VERIFY_NONE: g = string_cat(g, US"none"); break; | |
825 | case PDKIM_VERIFY_INVALID: | |
826 | switch (sig->verify_ext_status) | |
827 | { | |
828 | case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: | |
617d3932 | 829 | g = string_cat(g, US"tmperror (pubkey unavailable)\n\t\t"); break; |
dfbcb5ac | 830 | case PDKIM_VERIFY_INVALID_BUFFER_SIZE: |
617d3932 | 831 | g = string_cat(g, US"permerror (overlong public key record)\n\t\t"); break; |
dfbcb5ac JH |
832 | case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: |
833 | case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: | |
0e8aed8a | 834 | g = string_cat(g, US"neutral (public key record import problem)\n\t\t"); |
dfbcb5ac JH |
835 | break; |
836 | case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: | |
617d3932 | 837 | g = string_cat(g, US"neutral (signature tag missing or invalid)\n\t\t"); |
dfbcb5ac JH |
838 | break; |
839 | case PDKIM_VERIFY_INVALID_DKIM_VERSION: | |
617d3932 | 840 | g = string_cat(g, US"neutral (unsupported DKIM version)\n\t\t"); |
dfbcb5ac JH |
841 | break; |
842 | default: | |
617d3932 | 843 | g = string_cat(g, US"permerror (unspecified problem)\n\t\t"); break; |
dfbcb5ac JH |
844 | } |
845 | break; | |
846 | case PDKIM_VERIFY_FAIL: | |
847 | switch (sig->verify_ext_status) | |
848 | { | |
849 | case PDKIM_VERIFY_FAIL_BODY: | |
850 | g = string_cat(g, | |
617d3932 | 851 | US"fail (body hash mismatch; body probably modified in transit)\n\t\t"); |
dfbcb5ac JH |
852 | break; |
853 | case PDKIM_VERIFY_FAIL_MESSAGE: | |
854 | g = string_cat(g, | |
617d3932 | 855 | US"fail (signature did not verify; headers probably modified in transit)\n\t\t"); |
dfbcb5ac JH |
856 | break; |
857 | default: | |
617d3932 | 858 | g = string_cat(g, US"fail (unspecified reason)\n\t\t"); |
dfbcb5ac JH |
859 | break; |
860 | } | |
861 | break; | |
862 | case PDKIM_VERIFY_PASS: g = string_cat(g, US"pass"); break; | |
863 | default: g = string_cat(g, US"permerror"); break; | |
864 | } | |
865 | if (sig->domain) g = string_append(g, 2, US" header.d=", sig->domain); | |
866 | if (sig->identity) g = string_append(g, 2, US" header.i=", sig->identity); | |
867 | if (sig->selector) g = string_append(g, 2, US" header.s=", sig->selector); | |
868 | g = string_append(g, 2, US" header.a=", dkim_sig_to_a_tag(sig)); | |
869 | } | |
617d3932 JH |
870 | |
871 | DEBUG(D_acl) | |
872 | if (g->ptr == start) | |
873 | debug_printf("DKIM: no authres\n"); | |
874 | else | |
875 | debug_printf("DKIM: authres '%.*s'\n", g->ptr - start - 3, g->s + start + 3); | |
dfbcb5ac JH |
876 | return g; |
877 | } | |
878 | ||
879 | ||
970424a5 JH |
880 | # endif /*!MACRO_PREDEF*/ |
881 | #endif /*!DISABLE_DKIM*/ |