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