Copyright updates:
[exim.git] / src / src / acl.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* Copyright (c) The Exim Maintainers 2020 */
7 /* See the file NOTICE for conditions of use and distribution. */
8
9 /* Code for handling Access Control Lists (ACLs) */
10
11 #include "exim.h"
12
13
14 /* Default callout timeout */
15
16 #define CALLOUT_TIMEOUT_DEFAULT 30
17
18 /* ACL verb codes - keep in step with the table of verbs that follows */
19
20 enum { ACL_ACCEPT, ACL_DEFER, ACL_DENY, ACL_DISCARD, ACL_DROP, ACL_REQUIRE,
21 ACL_WARN };
22
23 /* ACL verbs */
24
25 static uschar *verbs[] = {
26 [ACL_ACCEPT] = US"accept",
27 [ACL_DEFER] = US"defer",
28 [ACL_DENY] = US"deny",
29 [ACL_DISCARD] = US"discard",
30 [ACL_DROP] = US"drop",
31 [ACL_REQUIRE] = US"require",
32 [ACL_WARN] = US"warn"
33 };
34
35 /* For each verb, the conditions for which "message" or "log_message" are used
36 are held as a bitmap. This is to avoid expanding the strings unnecessarily. For
37 "accept", the FAIL case is used only after "endpass", but that is selected in
38 the code. */
39
40 static int msgcond[] = {
41 [ACL_ACCEPT] = BIT(OK) | BIT(FAIL) | BIT(FAIL_DROP),
42 [ACL_DEFER] = BIT(OK),
43 [ACL_DENY] = BIT(OK),
44 [ACL_DISCARD] = BIT(OK) | BIT(FAIL) | BIT(FAIL_DROP),
45 [ACL_DROP] = BIT(OK),
46 [ACL_REQUIRE] = BIT(FAIL) | BIT(FAIL_DROP),
47 [ACL_WARN] = BIT(OK)
48 };
49
50 /* ACL condition and modifier codes - keep in step with the table that
51 follows.
52 down. */
53
54 enum { ACLC_ACL,
55 ACLC_ADD_HEADER,
56 ACLC_AUTHENTICATED,
57 #ifdef EXPERIMENTAL_BRIGHTMAIL
58 ACLC_BMI_OPTIN,
59 #endif
60 ACLC_CONDITION,
61 ACLC_CONTINUE,
62 ACLC_CONTROL,
63 #ifdef EXPERIMENTAL_DCC
64 ACLC_DCC,
65 #endif
66 #ifdef WITH_CONTENT_SCAN
67 ACLC_DECODE,
68 #endif
69 ACLC_DELAY,
70 #ifndef DISABLE_DKIM
71 ACLC_DKIM_SIGNER,
72 ACLC_DKIM_STATUS,
73 #endif
74 #ifdef SUPPORT_DMARC
75 ACLC_DMARC_STATUS,
76 #endif
77 ACLC_DNSLISTS,
78 ACLC_DOMAINS,
79 ACLC_ENCRYPTED,
80 ACLC_ENDPASS,
81 ACLC_HOSTS,
82 ACLC_LOCAL_PARTS,
83 ACLC_LOG_MESSAGE,
84 ACLC_LOG_REJECT_TARGET,
85 ACLC_LOGWRITE,
86 #ifdef WITH_CONTENT_SCAN
87 ACLC_MALWARE,
88 #endif
89 ACLC_MESSAGE,
90 #ifdef WITH_CONTENT_SCAN
91 ACLC_MIME_REGEX,
92 #endif
93 ACLC_QUEUE,
94 ACLC_RATELIMIT,
95 ACLC_RECIPIENTS,
96 #ifdef WITH_CONTENT_SCAN
97 ACLC_REGEX,
98 #endif
99 ACLC_REMOVE_HEADER,
100 ACLC_SENDER_DOMAINS,
101 ACLC_SENDERS,
102 ACLC_SET,
103 #ifdef WITH_CONTENT_SCAN
104 ACLC_SPAM,
105 #endif
106 #ifdef SUPPORT_SPF
107 ACLC_SPF,
108 ACLC_SPF_GUESS,
109 #endif
110 ACLC_UDPSEND,
111 ACLC_VERIFY };
112
113 /* ACL conditions/modifiers: "delay", "control", "continue", "endpass",
114 "message", "log_message", "log_reject_target", "logwrite", "queue" and "set" are
115 modifiers that look like conditions but always return TRUE. They are used for
116 their side effects. Do not invent new modifier names that result in one name
117 being the prefix of another; the binary-search in the list will go wrong. */
118
119 typedef struct condition_def {
120 uschar *name;
121
122 /* Flag to indicate the condition/modifier has a string expansion done
123 at the outer level. In the other cases, expansion already occurs in the
124 checking functions. */
125 BOOL expand_at_top:1;
126
127 BOOL is_modifier:1;
128
129 /* Bit map vector of which conditions and modifiers are not allowed at certain
130 times. For each condition and modifier, there's a bitmap of dis-allowed times.
131 For some, it is easier to specify the negation of a small number of allowed
132 times. */
133 unsigned forbids;
134
135 } condition_def;
136
137 static condition_def conditions[] = {
138 [ACLC_ACL] = { US"acl", FALSE, FALSE, 0 },
139
140 [ACLC_ADD_HEADER] = { US"add_header", TRUE, TRUE,
141 (unsigned int)
142 ~(ACL_BIT_MAIL | ACL_BIT_RCPT |
143 ACL_BIT_PREDATA | ACL_BIT_DATA |
144 #ifndef DISABLE_PRDR
145 ACL_BIT_PRDR |
146 #endif
147 ACL_BIT_MIME | ACL_BIT_NOTSMTP |
148 ACL_BIT_DKIM |
149 ACL_BIT_NOTSMTP_START),
150 },
151
152 [ACLC_AUTHENTICATED] = { US"authenticated", FALSE, FALSE,
153 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START |
154 ACL_BIT_CONNECT | ACL_BIT_HELO,
155 },
156 #ifdef EXPERIMENTAL_BRIGHTMAIL
157 [ACLC_BMI_OPTIN] = { US"bmi_optin", TRUE, TRUE,
158 ACL_BIT_AUTH |
159 ACL_BIT_CONNECT | ACL_BIT_HELO |
160 ACL_BIT_DATA | ACL_BIT_MIME |
161 # ifndef DISABLE_PRDR
162 ACL_BIT_PRDR |
163 # endif
164 ACL_BIT_ETRN | ACL_BIT_EXPN |
165 ACL_BIT_MAILAUTH |
166 ACL_BIT_MAIL | ACL_BIT_STARTTLS |
167 ACL_BIT_VRFY | ACL_BIT_PREDATA |
168 ACL_BIT_NOTSMTP_START,
169 },
170 #endif
171 [ACLC_CONDITION] = { US"condition", TRUE, FALSE, 0 },
172 [ACLC_CONTINUE] = { US"continue", TRUE, TRUE, 0 },
173
174 /* Certain types of control are always allowed, so we let it through
175 always and check in the control processing itself. */
176 [ACLC_CONTROL] = { US"control", TRUE, TRUE, 0 },
177
178 #ifdef EXPERIMENTAL_DCC
179 [ACLC_DCC] = { US"dcc", TRUE, FALSE,
180 (unsigned int)
181 ~(ACL_BIT_DATA |
182 # ifndef DISABLE_PRDR
183 ACL_BIT_PRDR |
184 # endif
185 ACL_BIT_NOTSMTP),
186 },
187 #endif
188 #ifdef WITH_CONTENT_SCAN
189 [ACLC_DECODE] = { US"decode", TRUE, FALSE, (unsigned int) ~ACL_BIT_MIME },
190
191 #endif
192 [ACLC_DELAY] = { US"delay", TRUE, TRUE, ACL_BIT_NOTQUIT },
193 #ifndef DISABLE_DKIM
194 [ACLC_DKIM_SIGNER] = { US"dkim_signers", TRUE, FALSE, (unsigned int) ~ACL_BIT_DKIM },
195 [ACLC_DKIM_STATUS] = { US"dkim_status", TRUE, FALSE, (unsigned int) ~ACL_BIT_DKIM },
196 #endif
197 #ifdef SUPPORT_DMARC
198 [ACLC_DMARC_STATUS] = { US"dmarc_status", TRUE, FALSE, (unsigned int) ~ACL_BIT_DATA },
199 #endif
200
201 /* Explicit key lookups can be made in non-smtp ACLs so pass
202 always and check in the verify processing itself. */
203 [ACLC_DNSLISTS] = { US"dnslists", TRUE, FALSE, 0 },
204
205 [ACLC_DOMAINS] = { US"domains", FALSE, FALSE,
206 (unsigned int)
207 ~(ACL_BIT_RCPT | ACL_BIT_VRFY
208 #ifndef DISABLE_PRDR
209 |ACL_BIT_PRDR
210 #endif
211 ),
212 },
213 [ACLC_ENCRYPTED] = { US"encrypted", FALSE, FALSE,
214 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START |
215 ACL_BIT_HELO,
216 },
217
218 [ACLC_ENDPASS] = { US"endpass", TRUE, TRUE, 0 },
219
220 [ACLC_HOSTS] = { US"hosts", FALSE, FALSE,
221 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START,
222 },
223 [ACLC_LOCAL_PARTS] = { US"local_parts", FALSE, FALSE,
224 (unsigned int)
225 ~(ACL_BIT_RCPT | ACL_BIT_VRFY
226 #ifndef DISABLE_PRDR
227 | ACL_BIT_PRDR
228 #endif
229 ),
230 },
231
232 [ACLC_LOG_MESSAGE] = { US"log_message", TRUE, TRUE, 0 },
233 [ACLC_LOG_REJECT_TARGET] = { US"log_reject_target", TRUE, TRUE, 0 },
234 [ACLC_LOGWRITE] = { US"logwrite", TRUE, TRUE, 0 },
235
236 #ifdef WITH_CONTENT_SCAN
237 [ACLC_MALWARE] = { US"malware", TRUE, FALSE,
238 (unsigned int)
239 ~(ACL_BIT_DATA |
240 # ifndef DISABLE_PRDR
241 ACL_BIT_PRDR |
242 # endif
243 ACL_BIT_NOTSMTP),
244 },
245 #endif
246
247 [ACLC_MESSAGE] = { US"message", TRUE, TRUE, 0 },
248 #ifdef WITH_CONTENT_SCAN
249 [ACLC_MIME_REGEX] = { US"mime_regex", TRUE, FALSE, (unsigned int) ~ACL_BIT_MIME },
250 #endif
251
252 [ACLC_QUEUE] = { US"queue", TRUE, TRUE,
253 ACL_BIT_NOTSMTP |
254 #ifndef DISABLE_PRDR
255 ACL_BIT_PRDR |
256 #endif
257 ACL_BIT_DATA,
258 },
259
260 [ACLC_RATELIMIT] = { US"ratelimit", TRUE, FALSE, 0 },
261 [ACLC_RECIPIENTS] = { US"recipients", FALSE, FALSE, (unsigned int) ~ACL_BIT_RCPT },
262
263 #ifdef WITH_CONTENT_SCAN
264 [ACLC_REGEX] = { US"regex", TRUE, FALSE,
265 (unsigned int)
266 ~(ACL_BIT_DATA |
267 # ifndef DISABLE_PRDR
268 ACL_BIT_PRDR |
269 # endif
270 ACL_BIT_NOTSMTP |
271 ACL_BIT_MIME),
272 },
273
274 #endif
275 [ACLC_REMOVE_HEADER] = { US"remove_header", TRUE, TRUE,
276 (unsigned int)
277 ~(ACL_BIT_MAIL|ACL_BIT_RCPT |
278 ACL_BIT_PREDATA | ACL_BIT_DATA |
279 #ifndef DISABLE_PRDR
280 ACL_BIT_PRDR |
281 #endif
282 ACL_BIT_MIME | ACL_BIT_NOTSMTP |
283 ACL_BIT_NOTSMTP_START),
284 },
285 [ACLC_SENDER_DOMAINS] = { US"sender_domains", FALSE, FALSE,
286 ACL_BIT_AUTH | ACL_BIT_CONNECT |
287 ACL_BIT_HELO |
288 ACL_BIT_MAILAUTH | ACL_BIT_QUIT |
289 ACL_BIT_ETRN | ACL_BIT_EXPN |
290 ACL_BIT_STARTTLS | ACL_BIT_VRFY,
291 },
292 [ACLC_SENDERS] = { US"senders", FALSE, FALSE,
293 ACL_BIT_AUTH | ACL_BIT_CONNECT |
294 ACL_BIT_HELO |
295 ACL_BIT_MAILAUTH | ACL_BIT_QUIT |
296 ACL_BIT_ETRN | ACL_BIT_EXPN |
297 ACL_BIT_STARTTLS | ACL_BIT_VRFY,
298 },
299
300 [ACLC_SET] = { US"set", TRUE, TRUE, 0 },
301
302 #ifdef WITH_CONTENT_SCAN
303 [ACLC_SPAM] = { US"spam", TRUE, FALSE,
304 (unsigned int) ~(ACL_BIT_DATA |
305 # ifndef DISABLE_PRDR
306 ACL_BIT_PRDR |
307 # endif
308 ACL_BIT_NOTSMTP),
309 },
310 #endif
311 #ifdef SUPPORT_SPF
312 [ACLC_SPF] = { US"spf", TRUE, FALSE,
313 ACL_BIT_AUTH | ACL_BIT_CONNECT |
314 ACL_BIT_HELO | ACL_BIT_MAILAUTH |
315 ACL_BIT_ETRN | ACL_BIT_EXPN |
316 ACL_BIT_STARTTLS | ACL_BIT_VRFY |
317 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START,
318 },
319 [ACLC_SPF_GUESS] = { US"spf_guess", TRUE, FALSE,
320 ACL_BIT_AUTH | ACL_BIT_CONNECT |
321 ACL_BIT_HELO | ACL_BIT_MAILAUTH |
322 ACL_BIT_ETRN | ACL_BIT_EXPN |
323 ACL_BIT_STARTTLS | ACL_BIT_VRFY |
324 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START,
325 },
326 #endif
327 [ACLC_UDPSEND] = { US"udpsend", TRUE, TRUE, 0 },
328
329 /* Certain types of verify are always allowed, so we let it through
330 always and check in the verify function itself */
331 [ACLC_VERIFY] = { US"verify", TRUE, FALSE, 0 },
332 };
333
334
335
336 /* Return values from decode_control(); used as index so keep in step
337 with the controls_list table that follows! */
338
339 enum {
340 CONTROL_AUTH_UNADVERTISED,
341 #ifdef EXPERIMENTAL_BRIGHTMAIL
342 CONTROL_BMI_RUN,
343 #endif
344 CONTROL_CASEFUL_LOCAL_PART,
345 CONTROL_CASELOWER_LOCAL_PART,
346 CONTROL_CUTTHROUGH_DELIVERY,
347 CONTROL_DEBUG,
348 #ifndef DISABLE_DKIM
349 CONTROL_DKIM_VERIFY,
350 #endif
351 #ifdef SUPPORT_DMARC
352 CONTROL_DMARC_VERIFY,
353 CONTROL_DMARC_FORENSIC,
354 #endif
355 CONTROL_DSCP,
356 CONTROL_ENFORCE_SYNC,
357 CONTROL_ERROR, /* pseudo-value for decode errors */
358 CONTROL_FAKEDEFER,
359 CONTROL_FAKEREJECT,
360 CONTROL_FREEZE,
361
362 CONTROL_NO_CALLOUT_FLUSH,
363 CONTROL_NO_DELAY_FLUSH,
364 CONTROL_NO_ENFORCE_SYNC,
365 #ifdef WITH_CONTENT_SCAN
366 CONTROL_NO_MBOX_UNSPOOL,
367 #endif
368 CONTROL_NO_MULTILINE,
369 CONTROL_NO_PIPELINING,
370
371 CONTROL_QUEUE,
372 CONTROL_SUBMISSION,
373 CONTROL_SUPPRESS_LOCAL_FIXUPS,
374 #ifdef SUPPORT_I18N
375 CONTROL_UTF8_DOWNCONVERT,
376 #endif
377 };
378
379
380
381 /* Structure listing various control arguments, with their characteristics.
382 For each control, there's a bitmap of dis-allowed times. For some, it is easier
383 to specify the negation of a small number of allowed times. */
384
385 typedef struct control_def {
386 uschar *name;
387 BOOL has_option; /* Has /option(s) following */
388 unsigned forbids; /* bitmap of dis-allowed times */
389 } control_def;
390
391 static control_def controls_list[] = {
392 /* name has_option forbids */
393 [CONTROL_AUTH_UNADVERTISED] =
394 { US"allow_auth_unadvertised", FALSE,
395 (unsigned)
396 ~(ACL_BIT_CONNECT | ACL_BIT_HELO)
397 },
398 #ifdef EXPERIMENTAL_BRIGHTMAIL
399 [CONTROL_BMI_RUN] =
400 { US"bmi_run", FALSE, 0 },
401 #endif
402 [CONTROL_CASEFUL_LOCAL_PART] =
403 { US"caseful_local_part", FALSE, (unsigned) ~ACL_BIT_RCPT },
404 [CONTROL_CASELOWER_LOCAL_PART] =
405 { US"caselower_local_part", FALSE, (unsigned) ~ACL_BIT_RCPT },
406 [CONTROL_CUTTHROUGH_DELIVERY] =
407 { US"cutthrough_delivery", TRUE, 0 },
408 [CONTROL_DEBUG] =
409 { US"debug", TRUE, 0 },
410
411 #ifndef DISABLE_DKIM
412 [CONTROL_DKIM_VERIFY] =
413 { US"dkim_disable_verify", FALSE,
414 ACL_BIT_DATA | ACL_BIT_NOTSMTP |
415 # ifndef DISABLE_PRDR
416 ACL_BIT_PRDR |
417 # endif
418 ACL_BIT_NOTSMTP_START
419 },
420 #endif
421
422 #ifdef SUPPORT_DMARC
423 [CONTROL_DMARC_VERIFY] =
424 { US"dmarc_disable_verify", FALSE,
425 ACL_BIT_DATA | ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START
426 },
427 [CONTROL_DMARC_FORENSIC] =
428 { US"dmarc_enable_forensic", FALSE,
429 ACL_BIT_DATA | ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START
430 },
431 #endif
432
433 [CONTROL_DSCP] =
434 { US"dscp", TRUE,
435 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START | ACL_BIT_NOTQUIT
436 },
437 [CONTROL_ENFORCE_SYNC] =
438 { US"enforce_sync", FALSE,
439 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START
440 },
441
442 /* Pseudo-value for decode errors */
443 [CONTROL_ERROR] =
444 { US"error", FALSE, 0 },
445
446 [CONTROL_FAKEDEFER] =
447 { US"fakedefer", TRUE,
448 (unsigned)
449 ~(ACL_BIT_MAIL | ACL_BIT_RCPT |
450 ACL_BIT_PREDATA | ACL_BIT_DATA |
451 #ifndef DISABLE_PRDR
452 ACL_BIT_PRDR |
453 #endif
454 ACL_BIT_MIME)
455 },
456 [CONTROL_FAKEREJECT] =
457 { US"fakereject", TRUE,
458 (unsigned)
459 ~(ACL_BIT_MAIL | ACL_BIT_RCPT |
460 ACL_BIT_PREDATA | ACL_BIT_DATA |
461 #ifndef DISABLE_PRDR
462 ACL_BIT_PRDR |
463 #endif
464 ACL_BIT_MIME)
465 },
466 [CONTROL_FREEZE] =
467 { US"freeze", TRUE,
468 (unsigned)
469 ~(ACL_BIT_MAIL | ACL_BIT_RCPT |
470 ACL_BIT_PREDATA | ACL_BIT_DATA |
471 // ACL_BIT_PRDR| /* Not allow one user to freeze for all */
472 ACL_BIT_NOTSMTP | ACL_BIT_MIME)
473 },
474
475 [CONTROL_NO_CALLOUT_FLUSH] =
476 { US"no_callout_flush", FALSE,
477 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START
478 },
479 [CONTROL_NO_DELAY_FLUSH] =
480 { US"no_delay_flush", FALSE,
481 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START
482 },
483
484 [CONTROL_NO_ENFORCE_SYNC] =
485 { US"no_enforce_sync", FALSE,
486 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START
487 },
488 #ifdef WITH_CONTENT_SCAN
489 [CONTROL_NO_MBOX_UNSPOOL] =
490 { US"no_mbox_unspool", FALSE,
491 (unsigned)
492 ~(ACL_BIT_MAIL | ACL_BIT_RCPT |
493 ACL_BIT_PREDATA | ACL_BIT_DATA |
494 // ACL_BIT_PRDR| /* Not allow one user to freeze for all */
495 ACL_BIT_MIME)
496 },
497 #endif
498 [CONTROL_NO_MULTILINE] =
499 { US"no_multiline_responses", FALSE,
500 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START
501 },
502 [CONTROL_NO_PIPELINING] =
503 { US"no_pipelining", FALSE,
504 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START
505 },
506
507 [CONTROL_QUEUE] =
508 { US"queue", TRUE,
509 (unsigned)
510 ~(ACL_BIT_MAIL | ACL_BIT_RCPT |
511 ACL_BIT_PREDATA | ACL_BIT_DATA |
512 // ACL_BIT_PRDR| /* Not allow one user to freeze for all */
513 ACL_BIT_NOTSMTP | ACL_BIT_MIME)
514 },
515
516 [CONTROL_SUBMISSION] =
517 { US"submission", TRUE,
518 (unsigned)
519 ~(ACL_BIT_MAIL | ACL_BIT_RCPT | ACL_BIT_PREDATA)
520 },
521 [CONTROL_SUPPRESS_LOCAL_FIXUPS] =
522 { US"suppress_local_fixups", FALSE,
523 (unsigned)
524 ~(ACL_BIT_MAIL | ACL_BIT_RCPT | ACL_BIT_PREDATA |
525 ACL_BIT_NOTSMTP_START)
526 },
527 #ifdef SUPPORT_I18N
528 [CONTROL_UTF8_DOWNCONVERT] =
529 { US"utf8_downconvert", TRUE, (unsigned) ~(ACL_BIT_RCPT | ACL_BIT_VRFY)
530 }
531 #endif
532 };
533
534 /* Support data structures for Client SMTP Authorization. acl_verify_csa()
535 caches its result in a tree to avoid repeated DNS queries. The result is an
536 integer code which is used as an index into the following tables of
537 explanatory strings and verification return codes. */
538
539 static tree_node *csa_cache = NULL;
540
541 enum { CSA_UNKNOWN, CSA_OK, CSA_DEFER_SRV, CSA_DEFER_ADDR,
542 CSA_FAIL_EXPLICIT, CSA_FAIL_DOMAIN, CSA_FAIL_NOADDR, CSA_FAIL_MISMATCH };
543
544 /* The acl_verify_csa() return code is translated into an acl_verify() return
545 code using the following table. It is OK unless the client is definitely not
546 authorized. This is because CSA is supposed to be optional for sending sites,
547 so recipients should not be too strict about checking it - especially because
548 DNS problems are quite likely to occur. It's possible to use $csa_status in
549 further ACL conditions to distinguish ok, unknown, and defer if required, but
550 the aim is to make the usual configuration simple. */
551
552 static int csa_return_code[] = {
553 [CSA_UNKNOWN] = OK,
554 [CSA_OK] = OK,
555 [CSA_DEFER_SRV] = OK,
556 [CSA_DEFER_ADDR] = OK,
557 [CSA_FAIL_EXPLICIT] = FAIL,
558 [CSA_FAIL_DOMAIN] = FAIL,
559 [CSA_FAIL_NOADDR] = FAIL,
560 [CSA_FAIL_MISMATCH] = FAIL
561 };
562
563 static uschar *csa_status_string[] = {
564 [CSA_UNKNOWN] = US"unknown",
565 [CSA_OK] = US"ok",
566 [CSA_DEFER_SRV] = US"defer",
567 [CSA_DEFER_ADDR] = US"defer",
568 [CSA_FAIL_EXPLICIT] = US"fail",
569 [CSA_FAIL_DOMAIN] = US"fail",
570 [CSA_FAIL_NOADDR] = US"fail",
571 [CSA_FAIL_MISMATCH] = US"fail"
572 };
573
574 static uschar *csa_reason_string[] = {
575 [CSA_UNKNOWN] = US"unknown",
576 [CSA_OK] = US"ok",
577 [CSA_DEFER_SRV] = US"deferred (SRV lookup failed)",
578 [CSA_DEFER_ADDR] = US"deferred (target address lookup failed)",
579 [CSA_FAIL_EXPLICIT] = US"failed (explicit authorization required)",
580 [CSA_FAIL_DOMAIN] = US"failed (host name not authorized)",
581 [CSA_FAIL_NOADDR] = US"failed (no authorized addresses)",
582 [CSA_FAIL_MISMATCH] = US"failed (client address mismatch)"
583 };
584
585 /* Options for the ratelimit condition. Note that there are two variants of
586 the per_rcpt option, depending on the ACL that is used to measure the rate.
587 However any ACL must be able to look up per_rcpt rates in /noupdate mode,
588 so the two variants must have the same internal representation as well as
589 the same configuration string. */
590
591 enum {
592 RATE_PER_WHAT, RATE_PER_CLASH, RATE_PER_ADDR, RATE_PER_BYTE, RATE_PER_CMD,
593 RATE_PER_CONN, RATE_PER_MAIL, RATE_PER_RCPT, RATE_PER_ALLRCPTS
594 };
595
596 #define RATE_SET(var,new) \
597 (((var) == RATE_PER_WHAT) ? ((var) = RATE_##new) : ((var) = RATE_PER_CLASH))
598
599 static uschar *ratelimit_option_string[] = {
600 [RATE_PER_WHAT] = US"?",
601 [RATE_PER_CLASH] = US"!",
602 [RATE_PER_ADDR] = US"per_addr",
603 [RATE_PER_BYTE] = US"per_byte",
604 [RATE_PER_CMD] = US"per_cmd",
605 [RATE_PER_CONN] = US"per_conn",
606 [RATE_PER_MAIL] = US"per_mail",
607 [RATE_PER_RCPT] = US"per_rcpt",
608 [RATE_PER_ALLRCPTS] = US"per_rcpt"
609 };
610
611 /* Enable recursion between acl_check_internal() and acl_check_condition() */
612
613 static int acl_check_wargs(int, address_item *, const uschar *, uschar **,
614 uschar **);
615
616
617 /*************************************************
618 * Find control in list *
619 *************************************************/
620
621 /* The lists are always in order, so binary chop can be used.
622
623 Arguments:
624 name the control name to search for
625 ol the first entry in the control list
626 last one more than the offset of the last entry in the control list
627
628 Returns: index of a control entry, or -1 if not found
629 */
630
631 static int
632 find_control(const uschar * name, control_def * ol, int last)
633 {
634 for (int first = 0; last > first; )
635 {
636 int middle = (first + last)/2;
637 uschar * s = ol[middle].name;
638 int c = Ustrncmp(name, s, Ustrlen(s));
639 if (c == 0) return middle;
640 else if (c > 0) first = middle + 1;
641 else last = middle;
642 }
643 return -1;
644 }
645
646
647
648 /*************************************************
649 * Pick out condition from list *
650 *************************************************/
651
652 /* Use a binary chop method
653
654 Arguments:
655 name name to find
656 list list of conditions
657 end size of list
658
659 Returns: offset in list, or -1 if not found
660 */
661
662 static int
663 acl_checkcondition(uschar * name, condition_def * list, int end)
664 {
665 for (int start = 0; start < end; )
666 {
667 int mid = (start + end)/2;
668 int c = Ustrcmp(name, list[mid].name);
669 if (c == 0) return mid;
670 if (c < 0) end = mid;
671 else start = mid + 1;
672 }
673 return -1;
674 }
675
676
677 /*************************************************
678 * Pick out name from list *
679 *************************************************/
680
681 /* Use a binary chop method
682
683 Arguments:
684 name name to find
685 list list of names
686 end size of list
687
688 Returns: offset in list, or -1 if not found
689 */
690
691 static int
692 acl_checkname(uschar *name, uschar **list, int end)
693 {
694 for (int start = 0; start < end; )
695 {
696 int mid = (start + end)/2;
697 int c = Ustrcmp(name, list[mid]);
698 if (c == 0) return mid;
699 if (c < 0) end = mid; else start = mid + 1;
700 }
701
702 return -1;
703 }
704
705
706 /*************************************************
707 * Read and parse one ACL *
708 *************************************************/
709
710 /* This function is called both from readconf in order to parse the ACLs in the
711 configuration file, and also when an ACL is encountered dynamically (e.g. as
712 the result of an expansion). It is given a function to call in order to
713 retrieve the lines of the ACL. This function handles skipping comments and
714 blank lines (where relevant).
715
716 Arguments:
717 func function to get next line of ACL
718 error where to put an error message
719
720 Returns: pointer to ACL, or NULL
721 NULL can be legal (empty ACL); in this case error will be NULL
722 */
723
724 acl_block *
725 acl_read(uschar *(*func)(void), uschar **error)
726 {
727 acl_block *yield = NULL;
728 acl_block **lastp = &yield;
729 acl_block *this = NULL;
730 acl_condition_block *cond;
731 acl_condition_block **condp = NULL;
732 uschar * s;
733
734 *error = NULL;
735
736 while ((s = (*func)()))
737 {
738 int v, c;
739 BOOL negated = FALSE;
740 uschar *saveline = s;
741 uschar name[64];
742
743 /* Conditions (but not verbs) are allowed to be negated by an initial
744 exclamation mark. */
745
746 if (Uskip_whitespace(&s) == '!')
747 {
748 negated = TRUE;
749 s++;
750 }
751
752 /* Read the name of a verb or a condition, or the start of a new ACL, which
753 can be started by a name, or by a macro definition. */
754
755 s = readconf_readname(name, sizeof(name), s);
756 if (*s == ':' || (isupper(name[0]) && *s == '=')) return yield;
757
758 /* If a verb is unrecognized, it may be another condition or modifier that
759 continues the previous verb. */
760
761 if ((v = acl_checkname(name, verbs, nelem(verbs))) < 0)
762 {
763 if (!this)
764 {
765 *error = string_sprintf("unknown ACL verb \"%s\" in \"%s\"", name,
766 saveline);
767 return NULL;
768 }
769 }
770
771 /* New verb */
772
773 else
774 {
775 if (negated)
776 {
777 *error = string_sprintf("malformed ACL line \"%s\"", saveline);
778 return NULL;
779 }
780 this = store_get(sizeof(acl_block), FALSE);
781 *lastp = this;
782 lastp = &(this->next);
783 this->next = NULL;
784 this->condition = NULL;
785 this->verb = v;
786 this->srcline = config_lineno; /* for debug output */
787 this->srcfile = config_filename; /**/
788 condp = &(this->condition);
789 if (*s == 0) continue; /* No condition on this line */
790 if (*s == '!')
791 {
792 negated = TRUE;
793 s++;
794 }
795 s = readconf_readname(name, sizeof(name), s); /* Condition name */
796 }
797
798 /* Handle a condition or modifier. */
799
800 if ((c = acl_checkcondition(name, conditions, nelem(conditions))) < 0)
801 {
802 *error = string_sprintf("unknown ACL condition/modifier in \"%s\"",
803 saveline);
804 return NULL;
805 }
806
807 /* The modifiers may not be negated */
808
809 if (negated && conditions[c].is_modifier)
810 {
811 *error = string_sprintf("ACL error: negation is not allowed with "
812 "\"%s\"", conditions[c].name);
813 return NULL;
814 }
815
816 /* ENDPASS may occur only with ACCEPT or DISCARD. */
817
818 if (c == ACLC_ENDPASS &&
819 this->verb != ACL_ACCEPT &&
820 this->verb != ACL_DISCARD)
821 {
822 *error = string_sprintf("ACL error: \"%s\" is not allowed with \"%s\"",
823 conditions[c].name, verbs[this->verb]);
824 return NULL;
825 }
826
827 cond = store_get(sizeof(acl_condition_block), FALSE);
828 cond->next = NULL;
829 cond->type = c;
830 cond->u.negated = negated;
831
832 *condp = cond;
833 condp = &(cond->next);
834
835 /* The "set" modifier is different in that its argument is "name=value"
836 rather than just a value, and we can check the validity of the name, which
837 gives us a variable name to insert into the data block. The original ACL
838 variable names were acl_c0 ... acl_c9 and acl_m0 ... acl_m9. This was
839 extended to 20 of each type, but after that people successfully argued for
840 arbitrary names. In the new scheme, the names must start with acl_c or acl_m.
841 After that, we allow alphanumerics and underscores, but the first character
842 after c or m must be a digit or an underscore. This retains backwards
843 compatibility. */
844
845 if (c == ACLC_SET)
846 #ifndef DISABLE_DKIM
847 if ( Ustrncmp(s, "dkim_verify_status", 18) == 0
848 || Ustrncmp(s, "dkim_verify_reason", 18) == 0)
849 {
850 uschar * endptr = s+18;
851
852 if (isalnum(*endptr))
853 {
854 *error = string_sprintf("invalid variable name after \"set\" in ACL "
855 "modifier \"set %s\" "
856 "(only \"dkim_verify_status\" or \"dkim_verify_reason\" permitted)",
857 s);
858 return NULL;
859 }
860 cond->u.varname = string_copyn(s, 18);
861 s = endptr;
862 Uskip_whitespace(&s);
863 }
864 else
865 #endif
866 {
867 uschar *endptr;
868
869 if (Ustrncmp(s, "acl_c", 5) != 0 && Ustrncmp(s, "acl_m", 5) != 0)
870 {
871 *error = string_sprintf("invalid variable name after \"set\" in ACL "
872 "modifier \"set %s\" (must start \"acl_c\" or \"acl_m\")", s);
873 return NULL;
874 }
875
876 endptr = s + 5;
877 if (!isdigit(*endptr) && *endptr != '_')
878 {
879 *error = string_sprintf("invalid variable name after \"set\" in ACL "
880 "modifier \"set %s\" (digit or underscore must follow acl_c or acl_m)",
881 s);
882 return NULL;
883 }
884
885 while (*endptr && *endptr != '=' && !isspace(*endptr))
886 {
887 if (!isalnum(*endptr) && *endptr != '_')
888 {
889 *error = string_sprintf("invalid character \"%c\" in variable name "
890 "in ACL modifier \"set %s\"", *endptr, s);
891 return NULL;
892 }
893 endptr++;
894 }
895
896 cond->u.varname = string_copyn(s + 4, endptr - s - 4);
897 s = endptr;
898 Uskip_whitespace(&s);
899 }
900
901 /* For "set", we are now positioned for the data. For the others, only
902 "endpass" has no data */
903
904 if (c != ACLC_ENDPASS)
905 {
906 if (*s++ != '=')
907 {
908 *error = string_sprintf("\"=\" missing after ACL \"%s\" %s", name,
909 conditions[c].is_modifier ? US"modifier" : US"condition");
910 return NULL;
911 }
912 Uskip_whitespace(&s);
913 cond->arg = string_copy(s);
914 }
915 }
916
917 return yield;
918 }
919
920
921
922 /*************************************************
923 * Set up added header line(s) *
924 *************************************************/
925
926 /* This function is called by the add_header modifier, and also from acl_warn()
927 to implement the now-deprecated way of adding header lines using "message" on a
928 "warn" verb. The argument is treated as a sequence of header lines which are
929 added to a chain, provided there isn't an identical one already there.
930
931 Argument: string of header lines
932 Returns: nothing
933 */
934
935 static void
936 setup_header(const uschar *hstring)
937 {
938 const uschar *p, *q;
939 int hlen = Ustrlen(hstring);
940
941 /* Ignore any leading newlines */
942 while (*hstring == '\n') hstring++, hlen--;
943
944 /* An empty string does nothing; ensure exactly one final newline. */
945 if (hlen <= 0) return;
946 if (hstring[--hlen] != '\n') /* no newline */
947 q = string_sprintf("%s\n", hstring);
948 else if (hstring[hlen-1] == '\n') /* double newline */
949 {
950 uschar * s = string_copy(hstring);
951 while(s[--hlen] == '\n')
952 s[hlen+1] = '\0';
953 q = s;
954 }
955 else
956 q = hstring;
957
958 /* Loop for multiple header lines, taking care about continuations */
959
960 for (p = q; *p; p = q)
961 {
962 const uschar *s;
963 uschar * hdr;
964 int newtype = htype_add_bot;
965 header_line **hptr = &acl_added_headers;
966
967 /* Find next header line within the string */
968
969 for (;;)
970 {
971 q = Ustrchr(q, '\n'); /* we know there was a newline */
972 if (*++q != ' ' && *q != '\t') break;
973 }
974
975 /* If the line starts with a colon, interpret the instruction for where to
976 add it. This temporarily sets up a new type. */
977
978 if (*p == ':')
979 {
980 if (strncmpic(p, US":after_received:", 16) == 0)
981 {
982 newtype = htype_add_rec;
983 p += 16;
984 }
985 else if (strncmpic(p, US":at_start_rfc:", 14) == 0)
986 {
987 newtype = htype_add_rfc;
988 p += 14;
989 }
990 else if (strncmpic(p, US":at_start:", 10) == 0)
991 {
992 newtype = htype_add_top;
993 p += 10;
994 }
995 else if (strncmpic(p, US":at_end:", 8) == 0)
996 {
997 newtype = htype_add_bot;
998 p += 8;
999 }
1000 while (*p == ' ' || *p == '\t') p++;
1001 }
1002
1003 /* See if this line starts with a header name, and if not, add X-ACL-Warn:
1004 to the front of it. */
1005
1006 for (s = p; s < q - 1; s++)
1007 if (*s == ':' || !isgraph(*s)) break;
1008
1009 hdr = string_sprintf("%s%.*s", *s == ':' ? "" : "X-ACL-Warn: ", (int) (q - p), p);
1010 hlen = Ustrlen(hdr);
1011
1012 /* See if this line has already been added */
1013
1014 while (*hptr)
1015 {
1016 if (Ustrncmp((*hptr)->text, hdr, hlen) == 0) break;
1017 hptr = &(*hptr)->next;
1018 }
1019
1020 /* Add if not previously present */
1021
1022 if (!*hptr)
1023 {
1024 /* The header_line struct itself is not tainted, though it points to
1025 possibly tainted data. */
1026 header_line * h = store_get(sizeof(header_line), FALSE);
1027 h->text = hdr;
1028 h->next = NULL;
1029 h->type = newtype;
1030 h->slen = hlen;
1031 *hptr = h;
1032 hptr = &h->next;
1033 }
1034 }
1035 }
1036
1037
1038
1039 /*************************************************
1040 * List the added header lines *
1041 *************************************************/
1042 uschar *
1043 fn_hdrs_added(void)
1044 {
1045 gstring * g = NULL;
1046
1047 for (header_line * h = acl_added_headers; h; h = h->next)
1048 {
1049 int i = h->slen;
1050 if (h->text[i-1] == '\n') i--;
1051 g = string_append_listele_n(g, '\n', h->text, i);
1052 }
1053
1054 return g ? g->s : NULL;
1055 }
1056
1057
1058 /*************************************************
1059 * Set up removed header line(s) *
1060 *************************************************/
1061
1062 /* This function is called by the remove_header modifier. The argument is
1063 treated as a sequence of header names which are added to a colon separated
1064 list, provided there isn't an identical one already there.
1065
1066 Argument: string of header names
1067 Returns: nothing
1068 */
1069
1070 static void
1071 setup_remove_header(const uschar *hnames)
1072 {
1073 if (*hnames)
1074 acl_removed_headers = acl_removed_headers
1075 ? string_sprintf("%s : %s", acl_removed_headers, hnames)
1076 : string_copy(hnames);
1077 }
1078
1079
1080
1081 /*************************************************
1082 * Handle warnings *
1083 *************************************************/
1084
1085 /* This function is called when a WARN verb's conditions are true. It adds to
1086 the message's headers, and/or writes information to the log. In each case, this
1087 only happens once (per message for headers, per connection for log).
1088
1089 ** NOTE: The header adding action using the "message" setting is historic, and
1090 its use is now deprecated. The new add_header modifier should be used instead.
1091
1092 Arguments:
1093 where ACL_WHERE_xxxx indicating which ACL this is
1094 user_message message for adding to headers
1095 log_message message for logging, if different
1096
1097 Returns: nothing
1098 */
1099
1100 static void
1101 acl_warn(int where, uschar *user_message, uschar *log_message)
1102 {
1103 if (log_message != NULL && log_message != user_message)
1104 {
1105 uschar *text;
1106 string_item *logged;
1107
1108 text = string_sprintf("%s Warning: %s", host_and_ident(TRUE),
1109 string_printing(log_message));
1110
1111 /* If a sender verification has failed, and the log message is "sender verify
1112 failed", add the failure message. */
1113
1114 if (sender_verified_failed != NULL &&
1115 sender_verified_failed->message != NULL &&
1116 strcmpic(log_message, US"sender verify failed") == 0)
1117 text = string_sprintf("%s: %s", text, sender_verified_failed->message);
1118
1119 /* Search previously logged warnings. They are kept in malloc
1120 store so they can be freed at the start of a new message. */
1121
1122 for (logged = acl_warn_logged; logged; logged = logged->next)
1123 if (Ustrcmp(logged->text, text) == 0) break;
1124
1125 if (!logged)
1126 {
1127 int length = Ustrlen(text) + 1;
1128 log_write(0, LOG_MAIN, "%s", text);
1129 logged = store_malloc(sizeof(string_item) + length);
1130 logged->text = US logged + sizeof(string_item);
1131 memcpy(logged->text, text, length);
1132 logged->next = acl_warn_logged;
1133 acl_warn_logged = logged;
1134 }
1135 }
1136
1137 /* If there's no user message, we are done. */
1138
1139 if (!user_message) return;
1140
1141 /* If this isn't a message ACL, we can't do anything with a user message.
1142 Log an error. */
1143
1144 if (where > ACL_WHERE_NOTSMTP)
1145 {
1146 log_write(0, LOG_MAIN|LOG_PANIC, "ACL \"warn\" with \"message\" setting "
1147 "found in a non-message (%s) ACL: cannot specify header lines here: "
1148 "message ignored", acl_wherenames[where]);
1149 return;
1150 }
1151
1152 /* The code for setting up header lines is now abstracted into a separate
1153 function so that it can be used for the add_header modifier as well. */
1154
1155 setup_header(user_message);
1156 }
1157
1158
1159
1160 /*************************************************
1161 * Verify and check reverse DNS *
1162 *************************************************/
1163
1164 /* Called from acl_verify() below. We look up the host name(s) of the client IP
1165 address if this has not yet been done. The host_name_lookup() function checks
1166 that one of these names resolves to an address list that contains the client IP
1167 address, so we don't actually have to do the check here.
1168
1169 Arguments:
1170 user_msgptr pointer for user message
1171 log_msgptr pointer for log message
1172
1173 Returns: OK verification condition succeeded
1174 FAIL verification failed
1175 DEFER there was a problem verifying
1176 */
1177
1178 static int
1179 acl_verify_reverse(uschar **user_msgptr, uschar **log_msgptr)
1180 {
1181 int rc;
1182
1183 user_msgptr = user_msgptr; /* stop compiler warning */
1184
1185 /* Previous success */
1186
1187 if (sender_host_name != NULL) return OK;
1188
1189 /* Previous failure */
1190
1191 if (host_lookup_failed)
1192 {
1193 *log_msgptr = string_sprintf("host lookup failed%s", host_lookup_msg);
1194 return FAIL;
1195 }
1196
1197 /* Need to do a lookup */
1198
1199 HDEBUG(D_acl)
1200 debug_printf_indent("looking up host name to force name/address consistency check\n");
1201
1202 if ((rc = host_name_lookup()) != OK)
1203 {
1204 *log_msgptr = rc == DEFER
1205 ? US"host lookup deferred for reverse lookup check"
1206 : string_sprintf("host lookup failed for reverse lookup check%s",
1207 host_lookup_msg);
1208 return rc; /* DEFER or FAIL */
1209 }
1210
1211 host_build_sender_fullhost();
1212 return OK;
1213 }
1214
1215
1216
1217 /*************************************************
1218 * Check client IP address matches CSA target *
1219 *************************************************/
1220
1221 /* Called from acl_verify_csa() below. This routine scans a section of a DNS
1222 response for address records belonging to the CSA target hostname. The section
1223 is specified by the reset argument, either RESET_ADDITIONAL or RESET_ANSWERS.
1224 If one of the addresses matches the client's IP address, then the client is
1225 authorized by CSA. If there are target IP addresses but none of them match
1226 then the client is using an unauthorized IP address. If there are no target IP
1227 addresses then the client cannot be using an authorized IP address. (This is
1228 an odd configuration - why didn't the SRV record have a weight of 1 instead?)
1229
1230 Arguments:
1231 dnsa the DNS answer block
1232 dnss a DNS scan block for us to use
1233 reset option specifying what portion to scan, as described above
1234 target the target hostname to use for matching RR names
1235
1236 Returns: CSA_OK successfully authorized
1237 CSA_FAIL_MISMATCH addresses found but none matched
1238 CSA_FAIL_NOADDR no target addresses found
1239 */
1240
1241 static int
1242 acl_verify_csa_address(dns_answer *dnsa, dns_scan *dnss, int reset,
1243 uschar *target)
1244 {
1245 int rc = CSA_FAIL_NOADDR;
1246
1247 for (dns_record * rr = dns_next_rr(dnsa, dnss, reset);
1248 rr;
1249 rr = dns_next_rr(dnsa, dnss, RESET_NEXT))
1250 {
1251 /* Check this is an address RR for the target hostname. */
1252
1253 if (rr->type != T_A
1254 #if HAVE_IPV6
1255 && rr->type != T_AAAA
1256 #endif
1257 ) continue;
1258
1259 if (strcmpic(target, rr->name) != 0) continue;
1260
1261 rc = CSA_FAIL_MISMATCH;
1262
1263 /* Turn the target address RR into a list of textual IP addresses and scan
1264 the list. There may be more than one if it is an A6 RR. */
1265
1266 for (dns_address * da = dns_address_from_rr(dnsa, rr); da; da = da->next)
1267 {
1268 /* If the client IP address matches the target IP address, it's good! */
1269
1270 DEBUG(D_acl) debug_printf_indent("CSA target address is %s\n", da->address);
1271
1272 if (strcmpic(sender_host_address, da->address) == 0) return CSA_OK;
1273 }
1274 }
1275
1276 /* If we found some target addresses but none of them matched, the client is
1277 using an unauthorized IP address, otherwise the target has no authorized IP
1278 addresses. */
1279
1280 return rc;
1281 }
1282
1283
1284
1285 /*************************************************
1286 * Verify Client SMTP Authorization *
1287 *************************************************/
1288
1289 /* Called from acl_verify() below. This routine calls dns_lookup_special()
1290 to find the CSA SRV record corresponding to the domain argument, or
1291 $sender_helo_name if no argument is provided. It then checks that the
1292 client is authorized, and that its IP address corresponds to the SRV
1293 target's address by calling acl_verify_csa_address() above. The address
1294 should have been returned in the DNS response's ADDITIONAL section, but if
1295 not we perform another DNS lookup to get it.
1296
1297 Arguments:
1298 domain pointer to optional parameter following verify = csa
1299
1300 Returns: CSA_UNKNOWN no valid CSA record found
1301 CSA_OK successfully authorized
1302 CSA_FAIL_* client is definitely not authorized
1303 CSA_DEFER_* there was a DNS problem
1304 */
1305
1306 static int
1307 acl_verify_csa(const uschar *domain)
1308 {
1309 tree_node *t;
1310 const uschar *found;
1311 int priority, weight, port;
1312 dns_answer * dnsa = store_get_dns_answer();
1313 dns_scan dnss;
1314 dns_record *rr;
1315 int rc, type;
1316 uschar target[256];
1317
1318 /* Work out the domain we are using for the CSA lookup. The default is the
1319 client's HELO domain. If the client has not said HELO, use its IP address
1320 instead. If it's a local client (exim -bs), CSA isn't applicable. */
1321
1322 while (isspace(*domain) && *domain != '\0') ++domain;
1323 if (*domain == '\0') domain = sender_helo_name;
1324 if (domain == NULL) domain = sender_host_address;
1325 if (sender_host_address == NULL) return CSA_UNKNOWN;
1326
1327 /* If we have an address literal, strip off the framing ready for turning it
1328 into a domain. The framing consists of matched square brackets possibly
1329 containing a keyword and a colon before the actual IP address. */
1330
1331 if (domain[0] == '[')
1332 {
1333 const uschar *start = Ustrchr(domain, ':');
1334 if (start == NULL) start = domain;
1335 domain = string_copyn(start + 1, Ustrlen(start) - 2);
1336 }
1337
1338 /* Turn domains that look like bare IP addresses into domains in the reverse
1339 DNS. This code also deals with address literals and $sender_host_address. It's
1340 not quite kosher to treat bare domains such as EHLO 192.0.2.57 the same as
1341 address literals, but it's probably the most friendly thing to do. This is an
1342 extension to CSA, so we allow it to be turned off for proper conformance. */
1343
1344 if (string_is_ip_address(domain, NULL) != 0)
1345 {
1346 if (!dns_csa_use_reverse) return CSA_UNKNOWN;
1347 domain = dns_build_reverse(domain);
1348 }
1349
1350 /* Find out if we've already done the CSA check for this domain. If we have,
1351 return the same result again. Otherwise build a new cached result structure
1352 for this domain. The name is filled in now, and the value is filled in when
1353 we return from this function. */
1354
1355 t = tree_search(csa_cache, domain);
1356 if (t != NULL) return t->data.val;
1357
1358 t = store_get_perm(sizeof(tree_node) + Ustrlen(domain), is_tainted(domain));
1359 Ustrcpy(t->name, domain);
1360 (void)tree_insertnode(&csa_cache, t);
1361
1362 /* Now we are ready to do the actual DNS lookup(s). */
1363
1364 found = domain;
1365 switch (dns_special_lookup(dnsa, domain, T_CSA, &found))
1366 {
1367 /* If something bad happened (most commonly DNS_AGAIN), defer. */
1368
1369 default:
1370 return t->data.val = CSA_DEFER_SRV;
1371
1372 /* If we found nothing, the client's authorization is unknown. */
1373
1374 case DNS_NOMATCH:
1375 case DNS_NODATA:
1376 return t->data.val = CSA_UNKNOWN;
1377
1378 /* We got something! Go on to look at the reply in more detail. */
1379
1380 case DNS_SUCCEED:
1381 break;
1382 }
1383
1384 /* Scan the reply for well-formed CSA SRV records. */
1385
1386 for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
1387 rr;
1388 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == T_SRV)
1389 {
1390 const uschar * p = rr->data;
1391
1392 /* Extract the numerical SRV fields (p is incremented) */
1393
1394 GETSHORT(priority, p);
1395 GETSHORT(weight, p);
1396 GETSHORT(port, p);
1397
1398 DEBUG(D_acl)
1399 debug_printf_indent("CSA priority=%d weight=%d port=%d\n", priority, weight, port);
1400
1401 /* Check the CSA version number */
1402
1403 if (priority != 1) continue;
1404
1405 /* If the domain does not have a CSA SRV record of its own (i.e. the domain
1406 found by dns_special_lookup() is a parent of the one we asked for), we check
1407 the subdomain assertions in the port field. At the moment there's only one
1408 assertion: legitimate SMTP clients are all explicitly authorized with CSA
1409 SRV records of their own. */
1410
1411 if (Ustrcmp(found, domain) != 0)
1412 return t->data.val = port & 1 ? CSA_FAIL_EXPLICIT : CSA_UNKNOWN;
1413
1414 /* This CSA SRV record refers directly to our domain, so we check the value
1415 in the weight field to work out the domain's authorization. 0 and 1 are
1416 unauthorized; 3 means the client is authorized but we can't check the IP
1417 address in order to authenticate it, so we treat it as unknown; values
1418 greater than 3 are undefined. */
1419
1420 if (weight < 2) return t->data.val = CSA_FAIL_DOMAIN;
1421
1422 if (weight > 2) continue;
1423
1424 /* Weight == 2, which means the domain is authorized. We must check that the
1425 client's IP address is listed as one of the SRV target addresses. Save the
1426 target hostname then break to scan the additional data for its addresses. */
1427
1428 (void)dn_expand(dnsa->answer, dnsa->answer + dnsa->answerlen, p,
1429 (DN_EXPAND_ARG4_TYPE)target, sizeof(target));
1430
1431 DEBUG(D_acl) debug_printf_indent("CSA target is %s\n", target);
1432
1433 break;
1434 }
1435
1436 /* If we didn't break the loop then no appropriate records were found. */
1437
1438 if (!rr) return t->data.val = CSA_UNKNOWN;
1439
1440 /* Do not check addresses if the target is ".", in accordance with RFC 2782.
1441 A target of "." indicates there are no valid addresses, so the client cannot
1442 be authorized. (This is an odd configuration because weight=2 target=. is
1443 equivalent to weight=1, but we check for it in order to keep load off the
1444 root name servers.) Note that dn_expand() turns "." into "". */
1445
1446 if (Ustrcmp(target, "") == 0) return t->data.val = CSA_FAIL_NOADDR;
1447
1448 /* Scan the additional section of the CSA SRV reply for addresses belonging
1449 to the target. If the name server didn't return any additional data (e.g.
1450 because it does not fully support SRV records), we need to do another lookup
1451 to obtain the target addresses; otherwise we have a definitive result. */
1452
1453 rc = acl_verify_csa_address(dnsa, &dnss, RESET_ADDITIONAL, target);
1454 if (rc != CSA_FAIL_NOADDR) return t->data.val = rc;
1455
1456 /* The DNS lookup type corresponds to the IP version used by the client. */
1457
1458 #if HAVE_IPV6
1459 if (Ustrchr(sender_host_address, ':') != NULL)
1460 type = T_AAAA;
1461 else
1462 #endif /* HAVE_IPV6 */
1463 type = T_A;
1464
1465
1466 lookup_dnssec_authenticated = NULL;
1467 switch (dns_lookup(dnsa, target, type, NULL))
1468 {
1469 /* If something bad happened (most commonly DNS_AGAIN), defer. */
1470
1471 default:
1472 return t->data.val = CSA_DEFER_ADDR;
1473
1474 /* If the query succeeded, scan the addresses and return the result. */
1475
1476 case DNS_SUCCEED:
1477 rc = acl_verify_csa_address(dnsa, &dnss, RESET_ANSWERS, target);
1478 if (rc != CSA_FAIL_NOADDR) return t->data.val = rc;
1479 /* else fall through */
1480
1481 /* If the target has no IP addresses, the client cannot have an authorized
1482 IP address. However, if the target site uses A6 records (not AAAA records)
1483 we have to do yet another lookup in order to check them. */
1484
1485 case DNS_NOMATCH:
1486 case DNS_NODATA:
1487 return t->data.val = CSA_FAIL_NOADDR;
1488 }
1489 }
1490
1491
1492
1493 /*************************************************
1494 * Handle verification (address & other) *
1495 *************************************************/
1496
1497 enum { VERIFY_REV_HOST_LKUP, VERIFY_CERT, VERIFY_HELO, VERIFY_CSA, VERIFY_HDR_SYNTAX,
1498 VERIFY_NOT_BLIND, VERIFY_HDR_SNDR, VERIFY_SNDR, VERIFY_RCPT,
1499 VERIFY_HDR_NAMES_ASCII, VERIFY_ARC
1500 };
1501 typedef struct {
1502 uschar * name;
1503 int value;
1504 unsigned where_allowed; /* bitmap */
1505 BOOL no_options; /* Never has /option(s) following */
1506 unsigned alt_opt_sep; /* >0 Non-/ option separator (custom parser) */
1507 } verify_type_t;
1508 static verify_type_t verify_type_list[] = {
1509 /* name value where no-opt opt-sep */
1510 { US"reverse_host_lookup", VERIFY_REV_HOST_LKUP, (unsigned)~0, FALSE, 0 },
1511 { US"certificate", VERIFY_CERT, (unsigned)~0, TRUE, 0 },
1512 { US"helo", VERIFY_HELO, (unsigned)~0, TRUE, 0 },
1513 { US"csa", VERIFY_CSA, (unsigned)~0, FALSE, 0 },
1514 { US"header_syntax", VERIFY_HDR_SYNTAX, ACL_BIT_DATA | ACL_BIT_NOTSMTP, TRUE, 0 },
1515 { US"not_blind", VERIFY_NOT_BLIND, ACL_BIT_DATA | ACL_BIT_NOTSMTP, FALSE, 0 },
1516 { US"header_sender", VERIFY_HDR_SNDR, ACL_BIT_DATA | ACL_BIT_NOTSMTP, FALSE, 0 },
1517 { US"sender", VERIFY_SNDR, ACL_BIT_MAIL | ACL_BIT_RCPT
1518 |ACL_BIT_PREDATA | ACL_BIT_DATA | ACL_BIT_NOTSMTP,
1519 FALSE, 6 },
1520 { US"recipient", VERIFY_RCPT, ACL_BIT_RCPT, FALSE, 0 },
1521 { US"header_names_ascii", VERIFY_HDR_NAMES_ASCII, ACL_BIT_DATA | ACL_BIT_NOTSMTP, TRUE, 0 },
1522 #ifdef EXPERIMENTAL_ARC
1523 { US"arc", VERIFY_ARC, ACL_BIT_DATA, FALSE , 0 },
1524 #endif
1525 };
1526
1527
1528 enum { CALLOUT_DEFER_OK, CALLOUT_NOCACHE, CALLOUT_RANDOM, CALLOUT_USE_SENDER,
1529 CALLOUT_USE_POSTMASTER, CALLOUT_POSTMASTER, CALLOUT_FULLPOSTMASTER,
1530 CALLOUT_MAILFROM, CALLOUT_POSTMASTER_MAILFROM, CALLOUT_MAXWAIT, CALLOUT_CONNECT,
1531 CALLOUT_HOLD, CALLOUT_TIME /* TIME must be last */
1532 };
1533 typedef struct {
1534 uschar * name;
1535 int value;
1536 int flag;
1537 BOOL has_option; /* Has =option(s) following */
1538 BOOL timeval; /* Has a time value */
1539 } callout_opt_t;
1540 static callout_opt_t callout_opt_list[] = {
1541 /* name value flag has-opt has-time */
1542 { US"defer_ok", CALLOUT_DEFER_OK, 0, FALSE, FALSE },
1543 { US"no_cache", CALLOUT_NOCACHE, vopt_callout_no_cache, FALSE, FALSE },
1544 { US"random", CALLOUT_RANDOM, vopt_callout_random, FALSE, FALSE },
1545 { US"use_sender", CALLOUT_USE_SENDER, vopt_callout_recipsender, FALSE, FALSE },
1546 { US"use_postmaster", CALLOUT_USE_POSTMASTER,vopt_callout_recippmaster, FALSE, FALSE },
1547 { US"postmaster_mailfrom",CALLOUT_POSTMASTER_MAILFROM,0, TRUE, FALSE },
1548 { US"postmaster", CALLOUT_POSTMASTER, 0, FALSE, FALSE },
1549 { US"fullpostmaster", CALLOUT_FULLPOSTMASTER,vopt_callout_fullpm, FALSE, FALSE },
1550 { US"mailfrom", CALLOUT_MAILFROM, 0, TRUE, FALSE },
1551 { US"maxwait", CALLOUT_MAXWAIT, 0, TRUE, TRUE },
1552 { US"connect", CALLOUT_CONNECT, 0, TRUE, TRUE },
1553 { US"hold", CALLOUT_HOLD, vopt_callout_hold, FALSE, FALSE },
1554 { NULL, CALLOUT_TIME, 0, FALSE, TRUE }
1555 };
1556
1557
1558
1559 /* This function implements the "verify" condition. It is called when
1560 encountered in any ACL, because some tests are almost always permitted. Some
1561 just don't make sense, and always fail (for example, an attempt to test a host
1562 lookup for a non-TCP/IP message). Others are restricted to certain ACLs.
1563
1564 Arguments:
1565 where where called from
1566 addr the recipient address that the ACL is handling, or NULL
1567 arg the argument of "verify"
1568 user_msgptr pointer for user message
1569 log_msgptr pointer for log message
1570 basic_errno where to put verify errno
1571
1572 Returns: OK verification condition succeeded
1573 FAIL verification failed
1574 DEFER there was a problem verifying
1575 ERROR syntax error
1576 */
1577
1578 static int
1579 acl_verify(int where, address_item *addr, const uschar *arg,
1580 uschar **user_msgptr, uschar **log_msgptr, int *basic_errno)
1581 {
1582 int sep = '/';
1583 int callout = -1;
1584 int callout_overall = -1;
1585 int callout_connect = -1;
1586 int verify_options = 0;
1587 int rc;
1588 BOOL verify_header_sender = FALSE;
1589 BOOL defer_ok = FALSE;
1590 BOOL callout_defer_ok = FALSE;
1591 BOOL no_details = FALSE;
1592 BOOL success_on_redirect = FALSE;
1593 address_item *sender_vaddr = NULL;
1594 uschar *verify_sender_address = NULL;
1595 uschar *pm_mailfrom = NULL;
1596 uschar *se_mailfrom = NULL;
1597
1598 /* Some of the verify items have slash-separated options; some do not. Diagnose
1599 an error if options are given for items that don't expect them.
1600 */
1601
1602 uschar *slash = Ustrchr(arg, '/');
1603 const uschar *list = arg;
1604 uschar *ss = string_nextinlist(&list, &sep, NULL, 0);
1605 verify_type_t * vp;
1606
1607 if (!ss) goto BAD_VERIFY;
1608
1609 /* Handle name/address consistency verification in a separate function. */
1610
1611 for (vp = verify_type_list;
1612 CS vp < CS verify_type_list + sizeof(verify_type_list);
1613 vp++
1614 )
1615 if (vp->alt_opt_sep ? strncmpic(ss, vp->name, vp->alt_opt_sep) == 0
1616 : strcmpic (ss, vp->name) == 0)
1617 break;
1618 if (CS vp >= CS verify_type_list + sizeof(verify_type_list))
1619 goto BAD_VERIFY;
1620
1621 if (vp->no_options && slash)
1622 {
1623 *log_msgptr = string_sprintf("unexpected '/' found in \"%s\" "
1624 "(this verify item has no options)", arg);
1625 return ERROR;
1626 }
1627 if (!(vp->where_allowed & BIT(where)))
1628 {
1629 *log_msgptr = string_sprintf("cannot verify %s in ACL for %s",
1630 vp->name, acl_wherenames[where]);
1631 return ERROR;
1632 }
1633 switch(vp->value)
1634 {
1635 case VERIFY_REV_HOST_LKUP:
1636 if (!sender_host_address) return OK;
1637 if ((rc = acl_verify_reverse(user_msgptr, log_msgptr)) == DEFER)
1638 while ((ss = string_nextinlist(&list, &sep, NULL, 0)))
1639 if (strcmpic(ss, US"defer_ok") == 0)
1640 return OK;
1641 return rc;
1642
1643 case VERIFY_CERT:
1644 /* TLS certificate verification is done at STARTTLS time; here we just
1645 test whether it was successful or not. (This is for optional verification; for
1646 mandatory verification, the connection doesn't last this long.) */
1647
1648 if (tls_in.certificate_verified) return OK;
1649 *user_msgptr = US"no verified certificate";
1650 return FAIL;
1651
1652 case VERIFY_HELO:
1653 /* We can test the result of optional HELO verification that might have
1654 occurred earlier. If not, we can attempt the verification now. */
1655
1656 if (!f.helo_verified && !f.helo_verify_failed) smtp_verify_helo();
1657 return f.helo_verified ? OK : FAIL;
1658
1659 case VERIFY_CSA:
1660 /* Do Client SMTP Authorization checks in a separate function, and turn the
1661 result code into user-friendly strings. */
1662
1663 rc = acl_verify_csa(list);
1664 *log_msgptr = *user_msgptr = string_sprintf("client SMTP authorization %s",
1665 csa_reason_string[rc]);
1666 csa_status = csa_status_string[rc];
1667 DEBUG(D_acl) debug_printf_indent("CSA result %s\n", csa_status);
1668 return csa_return_code[rc];
1669
1670 #ifdef EXPERIMENTAL_ARC
1671 case VERIFY_ARC:
1672 { /* Do Authenticated Received Chain checks in a separate function. */
1673 const uschar * condlist = CUS string_nextinlist(&list, &sep, NULL, 0);
1674 int csep = 0;
1675 uschar * cond;
1676
1677 if (!(arc_state = acl_verify_arc())) return DEFER;
1678 DEBUG(D_acl) debug_printf_indent("ARC verify result %s %s%s%s\n", arc_state,
1679 arc_state_reason ? "(":"", arc_state_reason, arc_state_reason ? ")":"");
1680
1681 if (!condlist) condlist = US"none:pass";
1682 while ((cond = string_nextinlist(&condlist, &csep, NULL, 0)))
1683 if (Ustrcmp(arc_state, cond) == 0) return OK;
1684 return FAIL;
1685 }
1686 #endif
1687
1688 case VERIFY_HDR_SYNTAX:
1689 /* Check that all relevant header lines have the correct 5322-syntax. If there is
1690 a syntax error, we return details of the error to the sender if configured to
1691 send out full details. (But a "message" setting on the ACL can override, as
1692 always). */
1693
1694 rc = verify_check_headers(log_msgptr);
1695 if (rc != OK && *log_msgptr)
1696 if (smtp_return_error_details)
1697 *user_msgptr = string_sprintf("Rejected after DATA: %s", *log_msgptr);
1698 else
1699 acl_verify_message = *log_msgptr;
1700 return rc;
1701
1702 case VERIFY_HDR_NAMES_ASCII:
1703 /* Check that all header names are true 7 bit strings
1704 See RFC 5322, 2.2. and RFC 6532, 3. */
1705
1706 rc = verify_check_header_names_ascii(log_msgptr);
1707 if (rc != OK && smtp_return_error_details && *log_msgptr)
1708 *user_msgptr = string_sprintf("Rejected after DATA: %s", *log_msgptr);
1709 return rc;
1710
1711 case VERIFY_NOT_BLIND:
1712 /* Check that no recipient of this message is "blind", that is, every envelope
1713 recipient must be mentioned in either To: or Cc:. */
1714 {
1715 BOOL case_sensitive = TRUE;
1716
1717 while ((ss = string_nextinlist(&list, &sep, NULL, 0)))
1718 if (strcmpic(ss, US"case_insensitive") == 0)
1719 case_sensitive = FALSE;
1720 else
1721 {
1722 *log_msgptr = string_sprintf("unknown option \"%s\" in ACL "
1723 "condition \"verify %s\"", ss, arg);
1724 return ERROR;
1725 }
1726
1727 if ((rc = verify_check_notblind(case_sensitive)) != OK)
1728 {
1729 *log_msgptr = US"bcc recipient detected";
1730 if (smtp_return_error_details)
1731 *user_msgptr = string_sprintf("Rejected after DATA: %s", *log_msgptr);
1732 }
1733 return rc;
1734 }
1735
1736 /* The remaining verification tests check recipient and sender addresses,
1737 either from the envelope or from the header. There are a number of
1738 slash-separated options that are common to all of them. */
1739
1740 case VERIFY_HDR_SNDR:
1741 verify_header_sender = TRUE;
1742 break;
1743
1744 case VERIFY_SNDR:
1745 /* In the case of a sender, this can optionally be followed by an address to use
1746 in place of the actual sender (rare special-case requirement). */
1747 {
1748 uschar *s = ss + 6;
1749 if (*s == 0)
1750 verify_sender_address = sender_address;
1751 else
1752 {
1753 while (isspace(*s)) s++;
1754 if (*s++ != '=') goto BAD_VERIFY;
1755 while (isspace(*s)) s++;
1756 verify_sender_address = string_copy(s);
1757 }
1758 }
1759 break;
1760
1761 case VERIFY_RCPT:
1762 break;
1763 }
1764
1765
1766
1767 /* Remaining items are optional; they apply to sender and recipient
1768 verification, including "header sender" verification. */
1769
1770 while ((ss = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1771 {
1772 if (strcmpic(ss, US"defer_ok") == 0) defer_ok = TRUE;
1773 else if (strcmpic(ss, US"no_details") == 0) no_details = TRUE;
1774 else if (strcmpic(ss, US"success_on_redirect") == 0) success_on_redirect = TRUE;
1775
1776 /* These two old options are left for backwards compatibility */
1777
1778 else if (strcmpic(ss, US"callout_defer_ok") == 0)
1779 {
1780 callout_defer_ok = TRUE;
1781 if (callout == -1) callout = CALLOUT_TIMEOUT_DEFAULT;
1782 }
1783
1784 else if (strcmpic(ss, US"check_postmaster") == 0)
1785 {
1786 pm_mailfrom = US"";
1787 if (callout == -1) callout = CALLOUT_TIMEOUT_DEFAULT;
1788 }
1789
1790 /* The callout option has a number of sub-options, comma separated */
1791
1792 else if (strncmpic(ss, US"callout", 7) == 0)
1793 {
1794 callout = CALLOUT_TIMEOUT_DEFAULT;
1795 ss += 7;
1796 if (*ss != 0)
1797 {
1798 while (isspace(*ss)) ss++;
1799 if (*ss++ == '=')
1800 {
1801 const uschar * sublist = ss;
1802 int optsep = ',';
1803 uschar buffer[256];
1804 uschar * opt;
1805
1806 while (isspace(*sublist)) sublist++;
1807 while ((opt = string_nextinlist(&sublist, &optsep, buffer, sizeof(buffer))))
1808 {
1809 callout_opt_t * op;
1810 double period = 1.0F;
1811
1812 for (op= callout_opt_list; op->name; op++)
1813 if (strncmpic(opt, op->name, Ustrlen(op->name)) == 0)
1814 break;
1815
1816 verify_options |= op->flag;
1817 if (op->has_option)
1818 {
1819 opt += Ustrlen(op->name);
1820 while (isspace(*opt)) opt++;
1821 if (*opt++ != '=')
1822 {
1823 *log_msgptr = string_sprintf("'=' expected after "
1824 "\"%s\" in ACL verify condition \"%s\"", op->name, arg);
1825 return ERROR;
1826 }
1827 while (isspace(*opt)) opt++;
1828 }
1829 if (op->timeval && (period = readconf_readtime(opt, 0, FALSE)) < 0)
1830 {
1831 *log_msgptr = string_sprintf("bad time value in ACL condition "
1832 "\"verify %s\"", arg);
1833 return ERROR;
1834 }
1835
1836 switch(op->value)
1837 {
1838 case CALLOUT_DEFER_OK: callout_defer_ok = TRUE; break;
1839 case CALLOUT_POSTMASTER: pm_mailfrom = US""; break;
1840 case CALLOUT_FULLPOSTMASTER: pm_mailfrom = US""; break;
1841 case CALLOUT_MAILFROM:
1842 if (!verify_header_sender)
1843 {
1844 *log_msgptr = string_sprintf("\"mailfrom\" is allowed as a "
1845 "callout option only for verify=header_sender (detected in ACL "
1846 "condition \"%s\")", arg);
1847 return ERROR;
1848 }
1849 se_mailfrom = string_copy(opt);
1850 break;
1851 case CALLOUT_POSTMASTER_MAILFROM: pm_mailfrom = string_copy(opt); break;
1852 case CALLOUT_MAXWAIT: callout_overall = period; break;
1853 case CALLOUT_CONNECT: callout_connect = period; break;
1854 case CALLOUT_TIME: callout = period; break;
1855 }
1856 }
1857 }
1858 else
1859 {
1860 *log_msgptr = string_sprintf("'=' expected after \"callout\" in "
1861 "ACL condition \"%s\"", arg);
1862 return ERROR;
1863 }
1864 }
1865 }
1866
1867 /* Option not recognized */
1868
1869 else
1870 {
1871 *log_msgptr = string_sprintf("unknown option \"%s\" in ACL "
1872 "condition \"verify %s\"", ss, arg);
1873 return ERROR;
1874 }
1875 }
1876
1877 if ((verify_options & (vopt_callout_recipsender|vopt_callout_recippmaster)) ==
1878 (vopt_callout_recipsender|vopt_callout_recippmaster))
1879 {
1880 *log_msgptr = US"only one of use_sender and use_postmaster can be set "
1881 "for a recipient callout";
1882 return ERROR;
1883 }
1884
1885 /* Handle sender-in-header verification. Default the user message to the log
1886 message if giving out verification details. */
1887
1888 if (verify_header_sender)
1889 {
1890 int verrno;
1891
1892 if ((rc = verify_check_header_address(user_msgptr, log_msgptr, callout,
1893 callout_overall, callout_connect, se_mailfrom, pm_mailfrom, verify_options,
1894 &verrno)) != OK)
1895 {
1896 *basic_errno = verrno;
1897 if (smtp_return_error_details)
1898 {
1899 if (!*user_msgptr && *log_msgptr)
1900 *user_msgptr = string_sprintf("Rejected after DATA: %s", *log_msgptr);
1901 if (rc == DEFER) f.acl_temp_details = TRUE;
1902 }
1903 }
1904 }
1905
1906 /* Handle a sender address. The default is to verify *the* sender address, but
1907 optionally a different address can be given, for special requirements. If the
1908 address is empty, we are dealing with a bounce message that has no sender, so
1909 we cannot do any checking. If the real sender address gets rewritten during
1910 verification (e.g. DNS widening), set the flag to stop it being rewritten again
1911 during message reception.
1912
1913 A list of verified "sender" addresses is kept to try to avoid doing to much
1914 work repetitively when there are multiple recipients in a message and they all
1915 require sender verification. However, when callouts are involved, it gets too
1916 complicated because different recipients may require different callout options.
1917 Therefore, we always do a full sender verify when any kind of callout is
1918 specified. Caching elsewhere, for instance in the DNS resolver and in the
1919 callout handling, should ensure that this is not terribly inefficient. */
1920
1921 else if (verify_sender_address)
1922 {
1923 if ((verify_options & (vopt_callout_recipsender|vopt_callout_recippmaster)))
1924 {
1925 *log_msgptr = US"use_sender or use_postmaster cannot be used for a "
1926 "sender verify callout";
1927 return ERROR;
1928 }
1929
1930 sender_vaddr = verify_checked_sender(verify_sender_address);
1931 if (sender_vaddr != NULL && /* Previously checked */
1932 callout <= 0) /* No callout needed this time */
1933 {
1934 /* If the "routed" flag is set, it means that routing worked before, so
1935 this check can give OK (the saved return code value, if set, belongs to a
1936 callout that was done previously). If the "routed" flag is not set, routing
1937 must have failed, so we use the saved return code. */
1938
1939 if (testflag(sender_vaddr, af_verify_routed))
1940 rc = OK;
1941 else
1942 {
1943 rc = sender_vaddr->special_action;
1944 *basic_errno = sender_vaddr->basic_errno;
1945 }
1946 HDEBUG(D_acl) debug_printf_indent("using cached sender verify result\n");
1947 }
1948
1949 /* Do a new verification, and cache the result. The cache is used to avoid
1950 verifying the sender multiple times for multiple RCPTs when callouts are not
1951 specified (see comments above).
1952
1953 The cache is also used on failure to give details in response to the first
1954 RCPT that gets bounced for this reason. However, this can be suppressed by
1955 the no_details option, which sets the flag that says "this detail has already
1956 been sent". The cache normally contains just one address, but there may be
1957 more in esoteric circumstances. */
1958
1959 else
1960 {
1961 BOOL routed = TRUE;
1962 uschar *save_address_data = deliver_address_data;
1963
1964 sender_vaddr = deliver_make_addr(verify_sender_address, TRUE);
1965 #ifdef SUPPORT_I18N
1966 if ((sender_vaddr->prop.utf8_msg = message_smtputf8))
1967 {
1968 sender_vaddr->prop.utf8_downcvt = message_utf8_downconvert == 1;
1969 sender_vaddr->prop.utf8_downcvt_maybe = message_utf8_downconvert == -1;
1970 }
1971 #endif
1972 if (no_details) setflag(sender_vaddr, af_sverify_told);
1973 if (verify_sender_address[0] != 0)
1974 {
1975 /* If this is the real sender address, save the unrewritten version
1976 for use later in receive. Otherwise, set a flag so that rewriting the
1977 sender in verify_address() does not update sender_address. */
1978
1979 if (verify_sender_address == sender_address)
1980 sender_address_unrewritten = sender_address;
1981 else
1982 verify_options |= vopt_fake_sender;
1983
1984 if (success_on_redirect)
1985 verify_options |= vopt_success_on_redirect;
1986
1987 /* The recipient, qualify, and expn options are never set in
1988 verify_options. */
1989
1990 rc = verify_address(sender_vaddr, NULL, verify_options, callout,
1991 callout_overall, callout_connect, se_mailfrom, pm_mailfrom, &routed);
1992
1993 HDEBUG(D_acl) debug_printf_indent("----------- end verify ------------\n");
1994
1995 if (rc != OK)
1996 *basic_errno = sender_vaddr->basic_errno;
1997 else
1998 DEBUG(D_acl)
1999 {
2000 if (Ustrcmp(sender_vaddr->address, verify_sender_address) != 0)
2001 debug_printf_indent("sender %s verified ok as %s\n",
2002 verify_sender_address, sender_vaddr->address);
2003 else
2004 debug_printf_indent("sender %s verified ok\n",
2005 verify_sender_address);
2006 }
2007 }
2008 else
2009 rc = OK; /* Null sender */
2010
2011 /* Cache the result code */
2012
2013 if (routed) setflag(sender_vaddr, af_verify_routed);
2014 if (callout > 0) setflag(sender_vaddr, af_verify_callout);
2015 sender_vaddr->special_action = rc;
2016 sender_vaddr->next = sender_verified_list;
2017 sender_verified_list = sender_vaddr;
2018
2019 /* Restore the recipient address data, which might have been clobbered by
2020 the sender verification. */
2021
2022 deliver_address_data = save_address_data;
2023 }
2024
2025 /* Put the sender address_data value into $sender_address_data */
2026
2027 sender_address_data = sender_vaddr->prop.address_data;
2028 }
2029
2030 /* A recipient address just gets a straightforward verify; again we must handle
2031 the DEFER overrides. */
2032
2033 else
2034 {
2035 address_item addr2;
2036
2037 if (success_on_redirect)
2038 verify_options |= vopt_success_on_redirect;
2039
2040 /* We must use a copy of the address for verification, because it might
2041 get rewritten. */
2042
2043 addr2 = *addr;
2044 rc = verify_address(&addr2, NULL, verify_options|vopt_is_recipient, callout,
2045 callout_overall, callout_connect, se_mailfrom, pm_mailfrom, NULL);
2046 HDEBUG(D_acl) debug_printf_indent("----------- end verify ------------\n");
2047
2048 *basic_errno = addr2.basic_errno;
2049 *log_msgptr = addr2.message;
2050 *user_msgptr = (addr2.user_message != NULL)?
2051 addr2.user_message : addr2.message;
2052
2053 /* Allow details for temporary error if the address is so flagged. */
2054 if (testflag((&addr2), af_pass_message)) f.acl_temp_details = TRUE;
2055
2056 /* Make $address_data visible */
2057 deliver_address_data = addr2.prop.address_data;
2058 }
2059
2060 /* We have a result from the relevant test. Handle defer overrides first. */
2061
2062 if (rc == DEFER && (defer_ok ||
2063 (callout_defer_ok && *basic_errno == ERRNO_CALLOUTDEFER)))
2064 {
2065 HDEBUG(D_acl) debug_printf_indent("verify defer overridden by %s\n",
2066 defer_ok? "defer_ok" : "callout_defer_ok");
2067 rc = OK;
2068 }
2069
2070 /* If we've failed a sender, set up a recipient message, and point
2071 sender_verified_failed to the address item that actually failed. */
2072
2073 if (rc != OK && verify_sender_address != NULL)
2074 {
2075 if (rc != DEFER)
2076 *log_msgptr = *user_msgptr = US"Sender verify failed";
2077 else if (*basic_errno != ERRNO_CALLOUTDEFER)
2078 *log_msgptr = *user_msgptr = US"Could not complete sender verify";
2079 else
2080 {
2081 *log_msgptr = US"Could not complete sender verify callout";
2082 *user_msgptr = smtp_return_error_details? sender_vaddr->user_message :
2083 *log_msgptr;
2084 }
2085
2086 sender_verified_failed = sender_vaddr;
2087 }
2088
2089 /* Verifying an address messes up the values of $domain and $local_part,
2090 so reset them before returning if this is a RCPT ACL. */
2091
2092 if (addr != NULL)
2093 {
2094 deliver_domain = addr->domain;
2095 deliver_localpart = addr->local_part;
2096 }
2097 return rc;
2098
2099 /* Syntax errors in the verify argument come here. */
2100
2101 BAD_VERIFY:
2102 *log_msgptr = string_sprintf("expected \"sender[=address]\", \"recipient\", "
2103 "\"helo\", \"header_syntax\", \"header_sender\", \"header_names_ascii\" "
2104 "or \"reverse_host_lookup\" at start of ACL condition "
2105 "\"verify %s\"", arg);
2106 return ERROR;
2107 }
2108
2109
2110
2111
2112 /*************************************************
2113 * Check argument for control= modifier *
2114 *************************************************/
2115
2116 /* Called from acl_check_condition() below.
2117 To handle the case "queue_only" we accept an _ in the
2118 initial / option-switch position.
2119
2120 Arguments:
2121 arg the argument string for control=
2122 pptr set to point to the terminating character
2123 where which ACL we are in
2124 log_msgptr for error messages
2125
2126 Returns: CONTROL_xxx value
2127 */
2128
2129 static int
2130 decode_control(const uschar *arg, const uschar **pptr, int where, uschar **log_msgptr)
2131 {
2132 int idx, len;
2133 control_def * d;
2134 uschar c;
2135
2136 if ( (idx = find_control(arg, controls_list, nelem(controls_list))) < 0
2137 || ( (c = arg[len = Ustrlen((d = controls_list+idx)->name)]) != 0
2138 && (!d->has_option || c != '/' && c != '_')
2139 ) )
2140 {
2141 *log_msgptr = string_sprintf("syntax error in \"control=%s\"", arg);
2142 return CONTROL_ERROR;
2143 }
2144
2145 *pptr = arg + len;
2146 return idx;
2147 }
2148
2149
2150
2151
2152 /*************************************************
2153 * Return a ratelimit error *
2154 *************************************************/
2155
2156 /* Called from acl_ratelimit() below
2157
2158 Arguments:
2159 log_msgptr for error messages
2160 format format string
2161 ... supplementary arguments
2162
2163 Returns: ERROR
2164 */
2165
2166 static int
2167 ratelimit_error(uschar **log_msgptr, const char *format, ...)
2168 {
2169 va_list ap;
2170 gstring * g =
2171 string_cat(NULL, US"error in arguments to \"ratelimit\" condition: ");
2172
2173 va_start(ap, format);
2174 g = string_vformat(g, SVFMT_EXTEND|SVFMT_REBUFFER, format, ap);
2175 va_end(ap);
2176
2177 gstring_release_unused(g);
2178 *log_msgptr = string_from_gstring(g);
2179 return ERROR;
2180 }
2181
2182
2183
2184
2185 /*************************************************
2186 * Handle rate limiting *
2187 *************************************************/
2188
2189 /* Called by acl_check_condition() below to calculate the result
2190 of the ACL ratelimit condition.
2191
2192 Note that the return value might be slightly unexpected: if the
2193 sender's rate is above the limit then the result is OK. This is
2194 similar to the dnslists condition, and is so that you can write
2195 ACL clauses like: defer ratelimit = 15 / 1h
2196
2197 Arguments:
2198 arg the option string for ratelimit=
2199 where ACL_WHERE_xxxx indicating which ACL this is
2200 log_msgptr for error messages
2201
2202 Returns: OK - Sender's rate is above limit
2203 FAIL - Sender's rate is below limit
2204 DEFER - Problem opening ratelimit database
2205 ERROR - Syntax error in options.
2206 */
2207
2208 static int
2209 acl_ratelimit(const uschar *arg, int where, uschar **log_msgptr)
2210 {
2211 double limit, period, count;
2212 uschar *ss;
2213 uschar *key = NULL;
2214 uschar *unique = NULL;
2215 int sep = '/';
2216 BOOL leaky = FALSE, strict = FALSE, readonly = FALSE;
2217 BOOL noupdate = FALSE, badacl = FALSE;
2218 int mode = RATE_PER_WHAT;
2219 int old_pool, rc;
2220 tree_node **anchor, *t;
2221 open_db dbblock, *dbm;
2222 int dbdb_size;
2223 dbdata_ratelimit *dbd;
2224 dbdata_ratelimit_unique *dbdb;
2225 struct timeval tv;
2226
2227 /* Parse the first two options and record their values in expansion
2228 variables. These variables allow the configuration to have informative
2229 error messages based on rate limits obtained from a table lookup. */
2230
2231 /* First is the maximum number of messages per period / maximum burst
2232 size, which must be greater than or equal to zero. Zero is useful for
2233 rate measurement as opposed to rate limiting. */
2234
2235 if (!(sender_rate_limit = string_nextinlist(&arg, &sep, NULL, 0)))
2236 return ratelimit_error(log_msgptr, "sender rate limit not set");
2237
2238 limit = Ustrtod(sender_rate_limit, &ss);
2239 if (tolower(*ss) == 'k') { limit *= 1024.0; ss++; }
2240 else if (tolower(*ss) == 'm') { limit *= 1024.0*1024.0; ss++; }
2241 else if (tolower(*ss) == 'g') { limit *= 1024.0*1024.0*1024.0; ss++; }
2242
2243 if (limit < 0.0 || *ss != '\0')
2244 return ratelimit_error(log_msgptr,
2245 "\"%s\" is not a positive number", sender_rate_limit);
2246
2247 /* Second is the rate measurement period / exponential smoothing time
2248 constant. This must be strictly greater than zero, because zero leads to
2249 run-time division errors. */
2250
2251 period = !(sender_rate_period = string_nextinlist(&arg, &sep, NULL, 0))
2252 ? -1.0 : readconf_readtime(sender_rate_period, 0, FALSE);
2253 if (period <= 0.0)
2254 return ratelimit_error(log_msgptr,
2255 "\"%s\" is not a time value", sender_rate_period);
2256
2257 /* By default we are counting one of something, but the per_rcpt,
2258 per_byte, and count options can change this. */
2259
2260 count = 1.0;
2261
2262 /* Parse the other options. */
2263
2264 while ((ss = string_nextinlist(&arg, &sep, NULL, 0)))
2265 {
2266 if (strcmpic(ss, US"leaky") == 0) leaky = TRUE;
2267 else if (strcmpic(ss, US"strict") == 0) strict = TRUE;
2268 else if (strcmpic(ss, US"noupdate") == 0) noupdate = TRUE;
2269 else if (strcmpic(ss, US"readonly") == 0) readonly = TRUE;
2270 else if (strcmpic(ss, US"per_cmd") == 0) RATE_SET(mode, PER_CMD);
2271 else if (strcmpic(ss, US"per_conn") == 0)
2272 {
2273 RATE_SET(mode, PER_CONN);
2274 if (where == ACL_WHERE_NOTSMTP || where == ACL_WHERE_NOTSMTP_START)
2275 badacl = TRUE;
2276 }
2277 else if (strcmpic(ss, US"per_mail") == 0)
2278 {
2279 RATE_SET(mode, PER_MAIL);
2280 if (where > ACL_WHERE_NOTSMTP) badacl = TRUE;
2281 }
2282 else if (strcmpic(ss, US"per_rcpt") == 0)
2283 {
2284 /* If we are running in the RCPT ACL, then we'll count the recipients
2285 one by one, but if we are running when we have accumulated the whole
2286 list then we'll add them all in one batch. */
2287 if (where == ACL_WHERE_RCPT)
2288 RATE_SET(mode, PER_RCPT);
2289 else if (where >= ACL_WHERE_PREDATA && where <= ACL_WHERE_NOTSMTP)
2290 RATE_SET(mode, PER_ALLRCPTS), count = (double)recipients_count;
2291 else if (where == ACL_WHERE_MAIL || where > ACL_WHERE_NOTSMTP)
2292 RATE_SET(mode, PER_RCPT), badacl = TRUE;
2293 }
2294 else if (strcmpic(ss, US"per_byte") == 0)
2295 {
2296 /* If we have not yet received the message data and there was no SIZE
2297 declaration on the MAIL command, then it's safe to just use a value of
2298 zero and let the recorded rate decay as if nothing happened. */
2299 RATE_SET(mode, PER_MAIL);
2300 if (where > ACL_WHERE_NOTSMTP) badacl = TRUE;
2301 else count = message_size < 0 ? 0.0 : (double)message_size;
2302 }
2303 else if (strcmpic(ss, US"per_addr") == 0)
2304 {
2305 RATE_SET(mode, PER_RCPT);
2306 if (where != ACL_WHERE_RCPT) badacl = TRUE, unique = US"*";
2307 else unique = string_sprintf("%s@%s", deliver_localpart, deliver_domain);
2308 }
2309 else if (strncmpic(ss, US"count=", 6) == 0)
2310 {
2311 uschar *e;
2312 count = Ustrtod(ss+6, &e);
2313 if (count < 0.0 || *e != '\0')
2314 return ratelimit_error(log_msgptr, "\"%s\" is not a positive number", ss);
2315 }
2316 else if (strncmpic(ss, US"unique=", 7) == 0)
2317 unique = string_copy(ss + 7);
2318 else if (!key)
2319 key = string_copy(ss);
2320 else
2321 key = string_sprintf("%s/%s", key, ss);
2322 }
2323
2324 /* Sanity check. When the badacl flag is set the update mode must either
2325 be readonly (which is the default if it is omitted) or, for backwards
2326 compatibility, a combination of noupdate and strict or leaky. */
2327
2328 if (mode == RATE_PER_CLASH)
2329 return ratelimit_error(log_msgptr, "conflicting per_* options");
2330 if (leaky + strict + readonly > 1)
2331 return ratelimit_error(log_msgptr, "conflicting update modes");
2332 if (badacl && (leaky || strict) && !noupdate)
2333 return ratelimit_error(log_msgptr,
2334 "\"%s\" must not have /leaky or /strict option, or cannot be used in %s ACL",
2335 ratelimit_option_string[mode], acl_wherenames[where]);
2336
2337 /* Set the default values of any unset options. In readonly mode we
2338 perform the rate computation without any increment so that its value
2339 decays to eventually allow over-limit senders through. */
2340
2341 if (noupdate) readonly = TRUE, leaky = strict = FALSE;
2342 if (badacl) readonly = TRUE;
2343 if (readonly) count = 0.0;
2344 if (!strict && !readonly) leaky = TRUE;
2345 if (mode == RATE_PER_WHAT) mode = RATE_PER_MAIL;
2346
2347 /* Create the lookup key. If there is no explicit key, use sender_host_address.
2348 If there is no sender_host_address (e.g. -bs or acl_not_smtp) then we simply
2349 omit it. The smoothing constant (sender_rate_period) and the per_xxx options
2350 are added to the key because they alter the meaning of the stored data. */
2351
2352 if (!key)
2353 key = !sender_host_address ? US"" : sender_host_address;
2354
2355 key = string_sprintf("%s/%s/%s%s",
2356 sender_rate_period,
2357 ratelimit_option_string[mode],
2358 unique == NULL ? "" : "unique/",
2359 key);
2360
2361 HDEBUG(D_acl)
2362 debug_printf_indent("ratelimit condition count=%.0f %.1f/%s\n", count, limit, key);
2363
2364 /* See if we have already computed the rate by looking in the relevant tree.
2365 For per-connection rate limiting, store tree nodes and dbdata in the permanent
2366 pool so that they survive across resets. In readonly mode we only remember the
2367 result for the rest of this command in case a later command changes it. After
2368 this bit of logic the code is independent of the per_* mode. */
2369
2370 old_pool = store_pool;
2371
2372 if (readonly)
2373 anchor = &ratelimiters_cmd;
2374 else switch(mode)
2375 {
2376 case RATE_PER_CONN:
2377 anchor = &ratelimiters_conn;
2378 store_pool = POOL_PERM;
2379 break;
2380 case RATE_PER_BYTE:
2381 case RATE_PER_MAIL:
2382 case RATE_PER_ALLRCPTS:
2383 anchor = &ratelimiters_mail;
2384 break;
2385 case RATE_PER_ADDR:
2386 case RATE_PER_CMD:
2387 case RATE_PER_RCPT:
2388 anchor = &ratelimiters_cmd;
2389 break;
2390 default:
2391 anchor = NULL; /* silence an "unused" complaint */
2392 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2393 "internal ACL error: unknown ratelimit mode %d", mode);
2394 break;
2395 }
2396
2397 if ((t = tree_search(*anchor, key)))
2398 {
2399 dbd = t->data.ptr;
2400 /* The following few lines duplicate some of the code below. */
2401 rc = (dbd->rate < limit)? FAIL : OK;
2402 store_pool = old_pool;
2403 sender_rate = string_sprintf("%.1f", dbd->rate);
2404 HDEBUG(D_acl)
2405 debug_printf_indent("ratelimit found pre-computed rate %s\n", sender_rate);
2406 return rc;
2407 }
2408
2409 /* We aren't using a pre-computed rate, so get a previously recorded rate
2410 from the database, which will be updated and written back if required. */
2411
2412 if (!(dbm = dbfn_open(US"ratelimit", O_RDWR, &dbblock, TRUE, TRUE)))
2413 {
2414 store_pool = old_pool;
2415 sender_rate = NULL;
2416 HDEBUG(D_acl) debug_printf_indent("ratelimit database not available\n");
2417 *log_msgptr = US"ratelimit database not available";
2418 return DEFER;
2419 }
2420 dbdb = dbfn_read_with_length(dbm, key, &dbdb_size);
2421 dbd = NULL;
2422
2423 gettimeofday(&tv, NULL);
2424
2425 if (dbdb)
2426 {
2427 /* Locate the basic ratelimit block inside the DB data. */
2428 HDEBUG(D_acl) debug_printf_indent("ratelimit found key in database\n");
2429 dbd = &dbdb->dbd;
2430
2431 /* Forget the old Bloom filter if it is too old, so that we count each
2432 repeating event once per period. We don't simply clear and re-use the old
2433 filter because we want its size to change if the limit changes. Note that
2434 we keep the dbd pointer for copying the rate into the new data block. */
2435
2436 if(unique && tv.tv_sec > dbdb->bloom_epoch + period)
2437 {
2438 HDEBUG(D_acl) debug_printf_indent("ratelimit discarding old Bloom filter\n");
2439 dbdb = NULL;
2440 }
2441
2442 /* Sanity check. */
2443
2444 if(unique && dbdb_size < sizeof(*dbdb))
2445 {
2446 HDEBUG(D_acl) debug_printf_indent("ratelimit discarding undersize Bloom filter\n");
2447 dbdb = NULL;
2448 }
2449 }
2450
2451 /* Allocate a new data block if the database lookup failed
2452 or the Bloom filter passed its age limit. */
2453
2454 if (!dbdb)
2455 {
2456 if (!unique)
2457 {
2458 /* No Bloom filter. This basic ratelimit block is initialized below. */
2459 HDEBUG(D_acl) debug_printf_indent("ratelimit creating new rate data block\n");
2460 dbdb_size = sizeof(*dbd);
2461 dbdb = store_get(dbdb_size, FALSE); /* not tainted */
2462 }
2463 else
2464 {
2465 int extra;
2466 HDEBUG(D_acl) debug_printf_indent("ratelimit creating new Bloom filter\n");
2467
2468 /* See the long comment below for an explanation of the magic number 2.
2469 The filter has a minimum size in case the rate limit is very small;
2470 this is determined by the definition of dbdata_ratelimit_unique. */
2471
2472 extra = (int)limit * 2 - sizeof(dbdb->bloom);
2473 if (extra < 0) extra = 0;
2474 dbdb_size = sizeof(*dbdb) + extra;
2475 dbdb = store_get(dbdb_size, FALSE); /* not tainted */
2476 dbdb->bloom_epoch = tv.tv_sec;
2477 dbdb->bloom_size = sizeof(dbdb->bloom) + extra;
2478 memset(dbdb->bloom, 0, dbdb->bloom_size);
2479
2480 /* Preserve any basic ratelimit data (which is our longer-term memory)
2481 by copying it from the discarded block. */
2482
2483 if (dbd)
2484 {
2485 dbdb->dbd = *dbd;
2486 dbd = &dbdb->dbd;
2487 }
2488 }
2489 }
2490
2491 /* If we are counting unique events, find out if this event is new or not.
2492 If the client repeats the event during the current period then it should be
2493 counted. We skip this code in readonly mode for efficiency, because any
2494 changes to the filter will be discarded and because count is already set to
2495 zero. */
2496
2497 if (unique && !readonly)
2498 {
2499 /* We identify unique events using a Bloom filter. (You can find my
2500 notes on Bloom filters at http://fanf.livejournal.com/81696.html)
2501 With the per_addr option, an "event" is a recipient address, though the
2502 user can use the unique option to define their own events. We only count
2503 an event if we have not seen it before.
2504
2505 We size the filter according to the rate limit, which (in leaky mode)
2506 is the limit on the population of the filter. We allow 16 bits of space
2507 per entry (see the construction code above) and we set (up to) 8 of them
2508 when inserting an element (see the loop below). The probability of a false
2509 positive (an event we have not seen before but which we fail to count) is
2510
2511 size = limit * 16
2512 numhash = 8
2513 allzero = exp(-numhash * pop / size)
2514 = exp(-0.5 * pop / limit)
2515 fpr = pow(1 - allzero, numhash)
2516
2517 For senders at the limit the fpr is 0.06% or 1 in 1700
2518 and for senders at half the limit it is 0.0006% or 1 in 170000
2519
2520 In strict mode the Bloom filter can fill up beyond the normal limit, in
2521 which case the false positive rate will rise. This means that the
2522 measured rate for very fast senders can bogusly drop off after a while.
2523
2524 At twice the limit, the fpr is 2.5% or 1 in 40
2525 At four times the limit, it is 31% or 1 in 3.2
2526
2527 It takes ln(pop/limit) periods for an over-limit burst of pop events to
2528 decay below the limit, and if this is more than one then the Bloom filter
2529 will be discarded before the decay gets that far. The false positive rate
2530 at this threshold is 9.3% or 1 in 10.7. */
2531
2532 BOOL seen;
2533 unsigned n, hash, hinc;
2534 uschar md5sum[16];
2535 md5 md5info;
2536
2537 /* Instead of using eight independent hash values, we combine two values
2538 using the formula h1 + n * h2. This does not harm the Bloom filter's
2539 performance, and means the amount of hash we need is independent of the
2540 number of bits we set in the filter. */
2541
2542 md5_start(&md5info);
2543 md5_end(&md5info, unique, Ustrlen(unique), md5sum);
2544 hash = md5sum[0] | md5sum[1] << 8 | md5sum[2] << 16 | md5sum[3] << 24;
2545 hinc = md5sum[4] | md5sum[5] << 8 | md5sum[6] << 16 | md5sum[7] << 24;
2546
2547 /* Scan the bits corresponding to this event. A zero bit means we have
2548 not seen it before. Ensure all bits are set to record this event. */
2549
2550 HDEBUG(D_acl) debug_printf_indent("ratelimit checking uniqueness of %s\n", unique);
2551
2552 seen = TRUE;
2553 for (n = 0; n < 8; n++, hash += hinc)
2554 {
2555 int bit = 1 << (hash % 8);
2556 int byte = (hash / 8) % dbdb->bloom_size;
2557 if ((dbdb->bloom[byte] & bit) == 0)
2558 {
2559 dbdb->bloom[byte] |= bit;
2560 seen = FALSE;
2561 }
2562 }
2563
2564 /* If this event has occurred before, do not count it. */
2565
2566 if (seen)
2567 {
2568 HDEBUG(D_acl) debug_printf_indent("ratelimit event found in Bloom filter\n");
2569 count = 0.0;
2570 }
2571 else
2572 HDEBUG(D_acl) debug_printf_indent("ratelimit event added to Bloom filter\n");
2573 }
2574
2575 /* If there was no previous ratelimit data block for this key, initialize
2576 the new one, otherwise update the block from the database. The initial rate
2577 is what would be computed by the code below for an infinite interval. */
2578
2579 if (!dbd)
2580 {
2581 HDEBUG(D_acl) debug_printf_indent("ratelimit initializing new key's rate data\n");
2582 dbd = &dbdb->dbd;
2583 dbd->time_stamp = tv.tv_sec;
2584 dbd->time_usec = tv.tv_usec;
2585 dbd->rate = count;
2586 }
2587 else
2588 {
2589 /* The smoothed rate is computed using an exponentially weighted moving
2590 average adjusted for variable sampling intervals. The standard EWMA for
2591 a fixed sampling interval is: f'(t) = (1 - a) * f(t) + a * f'(t - 1)
2592 where f() is the measured value and f'() is the smoothed value.
2593
2594 Old data decays out of the smoothed value exponentially, such that data n
2595 samples old is multiplied by a^n. The exponential decay time constant p
2596 is defined such that data p samples old is multiplied by 1/e, which means
2597 that a = exp(-1/p). We can maintain the same time constant for a variable
2598 sampling interval i by using a = exp(-i/p).
2599
2600 The rate we are measuring is messages per period, suitable for directly
2601 comparing with the limit. The average rate between now and the previous
2602 message is period / interval, which we feed into the EWMA as the sample.
2603
2604 It turns out that the number of messages required for the smoothed rate
2605 to reach the limit when they are sent in a burst is equal to the limit.
2606 This can be seen by analysing the value of the smoothed rate after N
2607 messages sent at even intervals. Let k = (1 - a) * p/i
2608
2609 rate_1 = (1 - a) * p/i + a * rate_0
2610 = k + a * rate_0
2611 rate_2 = k + a * rate_1
2612 = k + a * k + a^2 * rate_0
2613 rate_3 = k + a * k + a^2 * k + a^3 * rate_0
2614 rate_N = rate_0 * a^N + k * SUM(x=0..N-1)(a^x)
2615 = rate_0 * a^N + k * (1 - a^N) / (1 - a)
2616 = rate_0 * a^N + p/i * (1 - a^N)
2617
2618 When N is large, a^N -> 0 so rate_N -> p/i as desired.
2619
2620 rate_N = p/i + (rate_0 - p/i) * a^N
2621 a^N = (rate_N - p/i) / (rate_0 - p/i)
2622 N * -i/p = log((rate_N - p/i) / (rate_0 - p/i))
2623 N = p/i * log((rate_0 - p/i) / (rate_N - p/i))
2624
2625 Numerical analysis of the above equation, setting the computed rate to
2626 increase from rate_0 = 0 to rate_N = limit, shows that for large sending
2627 rates, p/i, the number of messages N = limit. So limit serves as both the
2628 maximum rate measured in messages per period, and the maximum number of
2629 messages that can be sent in a fast burst. */
2630
2631 double this_time = (double)tv.tv_sec
2632 + (double)tv.tv_usec / 1000000.0;
2633 double prev_time = (double)dbd->time_stamp
2634 + (double)dbd->time_usec / 1000000.0;
2635
2636 /* We must avoid division by zero, and deal gracefully with the clock going
2637 backwards. If we blunder ahead when time is in reverse then the computed
2638 rate will be bogus. To be safe we clamp interval to a very small number. */
2639
2640 double interval = this_time - prev_time <= 0.0 ? 1e-9
2641 : this_time - prev_time;
2642
2643 double i_over_p = interval / period;
2644 double a = exp(-i_over_p);
2645
2646 /* Combine the instantaneous rate (period / interval) with the previous rate
2647 using the smoothing factor a. In order to measure sized events, multiply the
2648 instantaneous rate by the count of bytes or recipients etc. */
2649
2650 dbd->time_stamp = tv.tv_sec;
2651 dbd->time_usec = tv.tv_usec;
2652 dbd->rate = (1 - a) * count / i_over_p + a * dbd->rate;
2653
2654 /* When events are very widely spaced the computed rate tends towards zero.
2655 Although this is accurate it turns out not to be useful for our purposes,
2656 especially when the first event after a long silence is the start of a spam
2657 run. A more useful model is that the rate for an isolated event should be the
2658 size of the event per the period size, ignoring the lack of events outside
2659 the current period and regardless of where the event falls in the period. So,
2660 if the interval was so long that the calculated rate is unhelpfully small, we
2661 re-initialize the rate. In the absence of higher-rate bursts, the condition
2662 below is true if the interval is greater than the period. */
2663
2664 if (dbd->rate < count) dbd->rate = count;
2665 }
2666
2667 /* Clients sending at the limit are considered to be over the limit.
2668 This matters for edge cases such as a limit of zero, when the client
2669 should be completely blocked. */
2670
2671 rc = dbd->rate < limit ? FAIL : OK;
2672
2673 /* Update the state if the rate is low or if we are being strict. If we
2674 are in leaky mode and the sender's rate is too high, we do not update
2675 the recorded rate in order to avoid an over-aggressive sender's retry
2676 rate preventing them from getting any email through. If readonly is set,
2677 neither leaky nor strict are set, so we do not do any updates. */
2678
2679 if ((rc == FAIL && leaky) || strict)
2680 {
2681 dbfn_write(dbm, key, dbdb, dbdb_size);
2682 HDEBUG(D_acl) debug_printf_indent("ratelimit db updated\n");
2683 }
2684 else
2685 {
2686 HDEBUG(D_acl) debug_printf_indent("ratelimit db not updated: %s\n",
2687 readonly? "readonly mode" : "over the limit, but leaky");
2688 }
2689
2690 dbfn_close(dbm);
2691
2692 /* Store the result in the tree for future reference. Take the taint status
2693 from the key for consistency even though it's unlikely we'll ever expand this. */
2694
2695 t = store_get(sizeof(tree_node) + Ustrlen(key), is_tainted(key));
2696 t->data.ptr = dbd;
2697 Ustrcpy(t->name, key);
2698 (void)tree_insertnode(anchor, t);
2699
2700 /* We create the formatted version of the sender's rate very late in
2701 order to ensure that it is done using the correct storage pool. */
2702
2703 store_pool = old_pool;
2704 sender_rate = string_sprintf("%.1f", dbd->rate);
2705
2706 HDEBUG(D_acl)
2707 debug_printf_indent("ratelimit computed rate %s\n", sender_rate);
2708
2709 return rc;
2710 }
2711
2712
2713
2714 /*************************************************
2715 * The udpsend ACL modifier *
2716 *************************************************/
2717
2718 /* Called by acl_check_condition() below.
2719
2720 Arguments:
2721 arg the option string for udpsend=
2722 log_msgptr for error messages
2723
2724 Returns: OK - Completed.
2725 DEFER - Problem with DNS lookup.
2726 ERROR - Syntax error in options.
2727 */
2728
2729 static int
2730 acl_udpsend(const uschar *arg, uschar **log_msgptr)
2731 {
2732 int sep = 0;
2733 uschar *hostname;
2734 uschar *portstr;
2735 uschar *portend;
2736 host_item *h;
2737 int portnum;
2738 int len;
2739 int r, s;
2740 uschar * errstr;
2741
2742 hostname = string_nextinlist(&arg, &sep, NULL, 0);
2743 portstr = string_nextinlist(&arg, &sep, NULL, 0);
2744
2745 if (!hostname)
2746 {
2747 *log_msgptr = US"missing destination host in \"udpsend\" modifier";
2748 return ERROR;
2749 }
2750 if (!portstr)
2751 {
2752 *log_msgptr = US"missing destination port in \"udpsend\" modifier";
2753 return ERROR;
2754 }
2755 if (!arg)
2756 {
2757 *log_msgptr = US"missing datagram payload in \"udpsend\" modifier";
2758 return ERROR;
2759 }
2760 portnum = Ustrtol(portstr, &portend, 10);
2761 if (*portend != '\0')
2762 {
2763 *log_msgptr = US"bad destination port in \"udpsend\" modifier";
2764 return ERROR;
2765 }
2766
2767 /* Make a single-item host list. */
2768 h = store_get(sizeof(host_item), FALSE);
2769 memset(h, 0, sizeof(host_item));
2770 h->name = hostname;
2771 h->port = portnum;
2772 h->mx = MX_NONE;
2773
2774 if (string_is_ip_address(hostname, NULL))
2775 h->address = hostname, r = HOST_FOUND;
2776 else
2777 r = host_find_byname(h, NULL, 0, NULL, FALSE);
2778 if (r == HOST_FIND_FAILED || r == HOST_FIND_AGAIN)
2779 {
2780 *log_msgptr = US"DNS lookup failed in \"udpsend\" modifier";
2781 return DEFER;
2782 }
2783
2784 HDEBUG(D_acl)
2785 debug_printf_indent("udpsend [%s]:%d %s\n", h->address, portnum, arg);
2786
2787 /*XXX this could better use sendto */
2788 r = s = ip_connectedsocket(SOCK_DGRAM, h->address, portnum, portnum,
2789 1, NULL, &errstr, NULL);
2790 if (r < 0) goto defer;
2791 len = Ustrlen(arg);
2792 r = send(s, arg, len, 0);
2793 if (r < 0)
2794 {
2795 errstr = US strerror(errno);
2796 close(s);
2797 goto defer;
2798 }
2799 close(s);
2800 if (r < len)
2801 {
2802 *log_msgptr =
2803 string_sprintf("\"udpsend\" truncated from %d to %d octets", len, r);
2804 return DEFER;
2805 }
2806
2807 HDEBUG(D_acl)
2808 debug_printf_indent("udpsend %d bytes\n", r);
2809
2810 return OK;
2811
2812 defer:
2813 *log_msgptr = string_sprintf("\"udpsend\" failed: %s", errstr);
2814 return DEFER;
2815 }
2816
2817
2818
2819 /*************************************************
2820 * Handle conditions/modifiers on an ACL item *
2821 *************************************************/
2822
2823 /* Called from acl_check() below.
2824
2825 Arguments:
2826 verb ACL verb
2827 cb ACL condition block - if NULL, result is OK
2828 where where called from
2829 addr the address being checked for RCPT, or NULL
2830 level the nesting level
2831 epp pointer to pass back TRUE if "endpass" encountered
2832 (applies only to "accept" and "discard")
2833 user_msgptr user message pointer
2834 log_msgptr log message pointer
2835 basic_errno pointer to where to put verify error
2836
2837 Returns: OK - all conditions are met
2838 DISCARD - an "acl" condition returned DISCARD - only allowed
2839 for "accept" or "discard" verbs
2840 FAIL - at least one condition fails
2841 FAIL_DROP - an "acl" condition returned FAIL_DROP
2842 DEFER - can't tell at the moment (typically, lookup defer,
2843 but can be temporary callout problem)
2844 ERROR - ERROR from nested ACL or expansion failure or other
2845 error
2846 */
2847
2848 static int
2849 acl_check_condition(int verb, acl_condition_block *cb, int where,
2850 address_item *addr, int level, BOOL *epp, uschar **user_msgptr,
2851 uschar **log_msgptr, int *basic_errno)
2852 {
2853 uschar *user_message = NULL;
2854 uschar *log_message = NULL;
2855 int rc = OK;
2856 #ifdef WITH_CONTENT_SCAN
2857 int sep = -'/';
2858 #endif
2859
2860 for (; cb; cb = cb->next)
2861 {
2862 const uschar *arg;
2863 int control_type;
2864
2865 /* The message and log_message items set up messages to be used in
2866 case of rejection. They are expanded later. */
2867
2868 if (cb->type == ACLC_MESSAGE)
2869 {
2870 HDEBUG(D_acl) debug_printf_indent(" message: %s\n", cb->arg);
2871 user_message = cb->arg;
2872 continue;
2873 }
2874
2875 if (cb->type == ACLC_LOG_MESSAGE)
2876 {
2877 HDEBUG(D_acl) debug_printf_indent("l_message: %s\n", cb->arg);
2878 log_message = cb->arg;
2879 continue;
2880 }
2881
2882 /* The endpass "condition" just sets a flag to show it occurred. This is
2883 checked at compile time to be on an "accept" or "discard" item. */
2884
2885 if (cb->type == ACLC_ENDPASS)
2886 {
2887 *epp = TRUE;
2888 continue;
2889 }
2890
2891 /* For other conditions and modifiers, the argument is expanded now for some
2892 of them, but not for all, because expansion happens down in some lower level
2893 checking functions in some cases. */
2894
2895 if (!conditions[cb->type].expand_at_top)
2896 arg = cb->arg;
2897 else if (!(arg = expand_string(cb->arg)))
2898 {
2899 if (f.expand_string_forcedfail) continue;
2900 *log_msgptr = string_sprintf("failed to expand ACL string \"%s\": %s",
2901 cb->arg, expand_string_message);
2902 return f.search_find_defer ? DEFER : ERROR;
2903 }
2904
2905 /* Show condition, and expanded condition if it's different */
2906
2907 HDEBUG(D_acl)
2908 {
2909 int lhswidth = 0;
2910 debug_printf_indent("check %s%s %n",
2911 (!conditions[cb->type].is_modifier && cb->u.negated)? "!":"",
2912 conditions[cb->type].name, &lhswidth);
2913
2914 if (cb->type == ACLC_SET)
2915 {
2916 #ifndef DISABLE_DKIM
2917 if ( Ustrcmp(cb->u.varname, "dkim_verify_status") == 0
2918 || Ustrcmp(cb->u.varname, "dkim_verify_reason") == 0)
2919 {
2920 debug_printf("%s ", cb->u.varname);
2921 lhswidth += 19;
2922 }
2923 else
2924 #endif
2925 {
2926 debug_printf("acl_%s ", cb->u.varname);
2927 lhswidth += 5 + Ustrlen(cb->u.varname);
2928 }
2929 }
2930
2931 debug_printf("= %s\n", cb->arg);
2932
2933 if (arg != cb->arg)
2934 debug_printf("%.*s= %s\n", lhswidth,
2935 US" ", CS arg);
2936 }
2937
2938 /* Check that this condition makes sense at this time */
2939
2940 if ((conditions[cb->type].forbids & (1 << where)) != 0)
2941 {
2942 *log_msgptr = string_sprintf("cannot %s %s condition in %s ACL",
2943 conditions[cb->type].is_modifier ? "use" : "test",
2944 conditions[cb->type].name, acl_wherenames[where]);
2945 return ERROR;
2946 }
2947
2948 /* Run the appropriate test for each condition, or take the appropriate
2949 action for the remaining modifiers. */
2950
2951 switch(cb->type)
2952 {
2953 case ACLC_ADD_HEADER:
2954 setup_header(arg);
2955 break;
2956
2957 /* A nested ACL that returns "discard" makes sense only for an "accept" or
2958 "discard" verb. */
2959
2960 case ACLC_ACL:
2961 rc = acl_check_wargs(where, addr, arg, user_msgptr, log_msgptr);
2962 if (rc == DISCARD && verb != ACL_ACCEPT && verb != ACL_DISCARD)
2963 {
2964 *log_msgptr = string_sprintf("nested ACL returned \"discard\" for "
2965 "\"%s\" command (only allowed with \"accept\" or \"discard\")",
2966 verbs[verb]);
2967 return ERROR;
2968 }
2969 break;
2970
2971 case ACLC_AUTHENTICATED:
2972 rc = sender_host_authenticated ? match_isinlist(sender_host_authenticated,
2973 &arg, 0, NULL, NULL, MCL_STRING, TRUE, NULL) : FAIL;
2974 break;
2975
2976 #ifdef EXPERIMENTAL_BRIGHTMAIL
2977 case ACLC_BMI_OPTIN:
2978 {
2979 int old_pool = store_pool;
2980 store_pool = POOL_PERM;
2981 bmi_current_optin = string_copy(arg);
2982 store_pool = old_pool;
2983 }
2984 break;
2985 #endif
2986
2987 case ACLC_CONDITION:
2988 /* The true/false parsing here should be kept in sync with that used in
2989 expand.c when dealing with ECOND_BOOL so that we don't have too many
2990 different definitions of what can be a boolean. */
2991 if (*arg == '-'
2992 ? Ustrspn(arg+1, "0123456789") == Ustrlen(arg+1) /* Negative number */
2993 : Ustrspn(arg, "0123456789") == Ustrlen(arg)) /* Digits, or empty */
2994 rc = (Uatoi(arg) == 0)? FAIL : OK;
2995 else
2996 rc = (strcmpic(arg, US"no") == 0 ||
2997 strcmpic(arg, US"false") == 0)? FAIL :
2998 (strcmpic(arg, US"yes") == 0 ||
2999 strcmpic(arg, US"true") == 0)? OK : DEFER;
3000 if (rc == DEFER)
3001 *log_msgptr = string_sprintf("invalid \"condition\" value \"%s\"", arg);
3002 break;
3003
3004 case ACLC_CONTINUE: /* Always succeeds */
3005 break;
3006
3007 case ACLC_CONTROL:
3008 {
3009 const uschar *p = NULL;
3010 control_type = decode_control(arg, &p, where, log_msgptr);
3011
3012 /* Check if this control makes sense at this time */
3013
3014 if (controls_list[control_type].forbids & (1 << where))
3015 {
3016 *log_msgptr = string_sprintf("cannot use \"control=%s\" in %s ACL",
3017 controls_list[control_type].name, acl_wherenames[where]);
3018 return ERROR;
3019 }
3020
3021 switch(control_type)
3022 {
3023 case CONTROL_AUTH_UNADVERTISED:
3024 f.allow_auth_unadvertised = TRUE;
3025 break;
3026
3027 #ifdef EXPERIMENTAL_BRIGHTMAIL
3028 case CONTROL_BMI_RUN:
3029 bmi_run = 1;
3030 break;
3031 #endif
3032
3033 #ifndef DISABLE_DKIM
3034 case CONTROL_DKIM_VERIFY:
3035 f.dkim_disable_verify = TRUE;
3036 # ifdef SUPPORT_DMARC
3037 /* Since DKIM was blocked, skip DMARC too */
3038 f.dmarc_disable_verify = TRUE;
3039 f.dmarc_enable_forensic = FALSE;
3040 # endif
3041 break;
3042 #endif
3043
3044 #ifdef SUPPORT_DMARC
3045 case CONTROL_DMARC_VERIFY:
3046 f.dmarc_disable_verify = TRUE;
3047 break;
3048
3049 case CONTROL_DMARC_FORENSIC:
3050 f.dmarc_enable_forensic = TRUE;
3051 break;
3052 #endif
3053
3054 case CONTROL_DSCP:
3055 if (*p == '/')
3056 {
3057 int fd, af, level, optname, value;
3058 /* If we are acting on stdin, the setsockopt may fail if stdin is not
3059 a socket; we can accept that, we'll just debug-log failures anyway. */
3060 fd = fileno(smtp_in);
3061 if ((af = ip_get_address_family(fd)) < 0)
3062 {
3063 HDEBUG(D_acl)
3064 debug_printf_indent("smtp input is probably not a socket [%s], not setting DSCP\n",
3065 strerror(errno));
3066 break;
3067 }
3068 if (dscp_lookup(p+1, af, &level, &optname, &value))
3069 if (setsockopt(fd, level, optname, &value, sizeof(value)) < 0)
3070 {
3071 HDEBUG(D_acl) debug_printf_indent("failed to set input DSCP[%s]: %s\n",
3072 p+1, strerror(errno));
3073 }
3074 else
3075 {
3076 HDEBUG(D_acl) debug_printf_indent("set input DSCP to \"%s\"\n", p+1);
3077 }
3078 else
3079 {
3080 *log_msgptr = string_sprintf("unrecognised DSCP value in \"control=%s\"", arg);
3081 return ERROR;
3082 }
3083 }
3084 else
3085 {
3086 *log_msgptr = string_sprintf("syntax error in \"control=%s\"", arg);
3087 return ERROR;
3088 }
3089 break;
3090
3091 case CONTROL_ERROR:
3092 return ERROR;
3093
3094 case CONTROL_CASEFUL_LOCAL_PART:
3095 deliver_localpart = addr->cc_local_part;
3096 break;
3097
3098 case CONTROL_CASELOWER_LOCAL_PART:
3099 deliver_localpart = addr->lc_local_part;
3100 break;
3101
3102 case CONTROL_ENFORCE_SYNC:
3103 smtp_enforce_sync = TRUE;
3104 break;
3105
3106 case CONTROL_NO_ENFORCE_SYNC:
3107 smtp_enforce_sync = FALSE;
3108 break;
3109
3110 #ifdef WITH_CONTENT_SCAN
3111 case CONTROL_NO_MBOX_UNSPOOL:
3112 f.no_mbox_unspool = TRUE;
3113 break;
3114 #endif
3115
3116 case CONTROL_NO_MULTILINE:
3117 f.no_multiline_responses = TRUE;
3118 break;
3119
3120 case CONTROL_NO_PIPELINING:
3121 f.pipelining_enable = FALSE;
3122 break;
3123
3124 case CONTROL_NO_DELAY_FLUSH:
3125 f.disable_delay_flush = TRUE;
3126 break;
3127
3128 case CONTROL_NO_CALLOUT_FLUSH:
3129 f.disable_callout_flush = TRUE;
3130 break;
3131
3132 case CONTROL_FAKEREJECT:
3133 cancel_cutthrough_connection(TRUE, US"fakereject");
3134 case CONTROL_FAKEDEFER:
3135 fake_response = (control_type == CONTROL_FAKEDEFER) ? DEFER : FAIL;
3136 if (*p == '/')
3137 {
3138 const uschar *pp = p + 1;
3139 while (*pp) pp++;
3140 fake_response_text = expand_string(string_copyn(p+1, pp-p-1));
3141 p = pp;
3142 }
3143 else /* Explicitly reset to default string */
3144 fake_response_text = US"Your message has been rejected but is being kept for evaluation.\nIf it was a legitimate message, it may still be delivered to the target recipient(s).";
3145 break;
3146
3147 case CONTROL_FREEZE:
3148 f.deliver_freeze = TRUE;
3149 deliver_frozen_at = time(NULL);
3150 freeze_tell = freeze_tell_config; /* Reset to configured value */
3151 if (Ustrncmp(p, "/no_tell", 8) == 0)
3152 {
3153 p += 8;
3154 freeze_tell = NULL;
3155 }
3156 if (*p)
3157 {
3158 *log_msgptr = string_sprintf("syntax error in \"control=%s\"", arg);
3159 return ERROR;
3160 }
3161 cancel_cutthrough_connection(TRUE, US"item frozen");
3162 break;
3163
3164 case CONTROL_QUEUE:
3165 f.queue_only_policy = TRUE;
3166 if (Ustrcmp(p, "_only") == 0)
3167 p += 5;
3168 else while (*p == '/')
3169 if (Ustrncmp(p, "/only", 5) == 0)
3170 { p += 5; f.queue_smtp = FALSE; }
3171 else if (Ustrncmp(p, "/first_pass_route", 17) == 0)
3172 { p += 17; f.queue_smtp = TRUE; }
3173 else
3174 break;
3175 cancel_cutthrough_connection(TRUE, US"queueing forced");
3176 break;
3177
3178 case CONTROL_SUBMISSION:
3179 originator_name = US"";
3180 f.submission_mode = TRUE;
3181 while (*p == '/')
3182 {
3183 if (Ustrncmp(p, "/sender_retain", 14) == 0)
3184 {
3185 p += 14;
3186 f.active_local_sender_retain = TRUE;
3187 f.active_local_from_check = FALSE;
3188 }
3189 else if (Ustrncmp(p, "/domain=", 8) == 0)
3190 {
3191 const uschar *pp = p + 8;
3192 while (*pp && *pp != '/') pp++;
3193 submission_domain = string_copyn(p+8, pp-p-8);
3194 p = pp;
3195 }
3196 /* The name= option must be last, because it swallows the rest of
3197 the string. */
3198 else if (Ustrncmp(p, "/name=", 6) == 0)
3199 {
3200 const uschar *pp = p + 6;
3201 while (*pp) pp++;
3202 submission_name = string_copy(parse_fix_phrase(p+6, pp-p-6,
3203 big_buffer, big_buffer_size));
3204 p = pp;
3205 }
3206 else break;
3207 }
3208 if (*p)
3209 {
3210 *log_msgptr = string_sprintf("syntax error in \"control=%s\"", arg);
3211 return ERROR;
3212 }
3213 break;
3214
3215 case CONTROL_DEBUG:
3216 {
3217 uschar * debug_tag = NULL;
3218 uschar * debug_opts = NULL;
3219 BOOL kill = FALSE;
3220
3221 while (*p == '/')
3222 {
3223 const uschar * pp = p+1;
3224 if (Ustrncmp(pp, "tag=", 4) == 0)
3225 {
3226 for (pp += 4; *pp && *pp != '/';) pp++;
3227 debug_tag = string_copyn(p+5, pp-p-5);
3228 }
3229 else if (Ustrncmp(pp, "opts=", 5) == 0)
3230 {
3231 for (pp += 5; *pp && *pp != '/';) pp++;
3232 debug_opts = string_copyn(p+6, pp-p-6);
3233 }
3234 else if (Ustrncmp(pp, "kill", 4) == 0)
3235 {
3236 for (pp += 4; *pp && *pp != '/';) pp++;
3237 kill = TRUE;
3238 }
3239 else
3240 while (*pp && *pp != '/') pp++;
3241 p = pp;
3242 }
3243
3244 if (kill)
3245 debug_logging_stop();
3246 else
3247 debug_logging_activate(debug_tag, debug_opts);
3248 break;
3249 }
3250
3251 case CONTROL_SUPPRESS_LOCAL_FIXUPS:
3252 f.suppress_local_fixups = TRUE;
3253 break;
3254
3255 case CONTROL_CUTTHROUGH_DELIVERY:
3256 {
3257 uschar * ignored = NULL;
3258 #ifndef DISABLE_PRDR
3259 if (prdr_requested)
3260 #else
3261 if (0)
3262 #endif
3263 /* Too hard to think about for now. We might in future cutthrough
3264 the case where both sides handle prdr and this-node prdr acl
3265 is "accept" */
3266 ignored = US"PRDR active";
3267 else
3268 {
3269 if (f.deliver_freeze)
3270 ignored = US"frozen";
3271 else if (f.queue_only_policy)
3272 ignored = US"queue-only";
3273 else if (fake_response == FAIL)
3274 ignored = US"fakereject";
3275 else
3276 {
3277 if (rcpt_count == 1)
3278 {
3279 cutthrough.delivery = TRUE; /* control accepted */
3280 while (*p == '/')
3281 {
3282 const uschar * pp = p+1;
3283 if (Ustrncmp(pp, "defer=", 6) == 0)
3284 {
3285 pp += 6;
3286 if (Ustrncmp(pp, "pass", 4) == 0) cutthrough.defer_pass = TRUE;
3287 /* else if (Ustrncmp(pp, "spool") == 0) ; default */
3288 }
3289 else
3290 while (*pp && *pp != '/') pp++;
3291 p = pp;
3292 }
3293 }
3294 else
3295 ignored = US"nonfirst rcpt";
3296 }
3297 }
3298 DEBUG(D_acl) if (ignored)
3299 debug_printf(" cutthrough request ignored on %s item\n", ignored);
3300 }
3301 break;
3302
3303 #ifdef SUPPORT_I18N
3304 case CONTROL_UTF8_DOWNCONVERT:
3305 if (*p == '/')
3306 {
3307 if (p[1] == '1')
3308 {
3309 message_utf8_downconvert = 1;
3310 addr->prop.utf8_downcvt = TRUE;
3311 addr->prop.utf8_downcvt_maybe = FALSE;
3312 p += 2;
3313 break;
3314 }
3315 if (p[1] == '0')
3316 {
3317 message_utf8_downconvert = 0;
3318 addr->prop.utf8_downcvt = FALSE;
3319 addr->prop.utf8_downcvt_maybe = FALSE;
3320 p += 2;
3321 break;
3322 }
3323 if (p[1] == '-' && p[2] == '1')
3324 {
3325 message_utf8_downconvert = -1;
3326 addr->prop.utf8_downcvt = FALSE;
3327 addr->prop.utf8_downcvt_maybe = TRUE;
3328 p += 3;
3329 break;
3330 }
3331 *log_msgptr = US"bad option value for control=utf8_downconvert";
3332 }
3333 else
3334 {
3335 message_utf8_downconvert = 1;
3336 addr->prop.utf8_downcvt = TRUE;
3337 addr->prop.utf8_downcvt_maybe = FALSE;
3338 break;
3339 }
3340 return ERROR;
3341 #endif
3342
3343 }
3344 break;
3345 }
3346
3347 #ifdef EXPERIMENTAL_DCC
3348 case ACLC_DCC:
3349 {
3350 /* Separate the regular expression and any optional parameters. */
3351 const uschar * list = arg;
3352 uschar *ss = string_nextinlist(&list, &sep, big_buffer, big_buffer_size);
3353 /* Run the dcc backend. */
3354 rc = dcc_process(&ss);
3355 /* Modify return code based upon the existence of options. */
3356 while ((ss = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
3357 if (strcmpic(ss, US"defer_ok") == 0 && rc == DEFER)
3358 rc = FAIL; /* FAIL so that the message is passed to the next ACL */
3359 }
3360 break;
3361 #endif
3362
3363 #ifdef WITH_CONTENT_SCAN
3364 case ACLC_DECODE:
3365 rc = mime_decode(&arg);
3366 break;
3367 #endif
3368
3369 case ACLC_DELAY:
3370 {
3371 int delay = readconf_readtime(arg, 0, FALSE);
3372 if (delay < 0)
3373 {
3374 *log_msgptr = string_sprintf("syntax error in argument for \"delay\" "
3375 "modifier: \"%s\" is not a time value", arg);
3376 return ERROR;
3377 }
3378 else
3379 {
3380 HDEBUG(D_acl) debug_printf_indent("delay modifier requests %d-second delay\n",
3381 delay);
3382 if (host_checking)
3383 {
3384 HDEBUG(D_acl)
3385 debug_printf_indent("delay skipped in -bh checking mode\n");
3386 }
3387
3388 /* NOTE 1: Remember that we may be
3389 dealing with stdin/stdout here, in addition to TCP/IP connections.
3390 Also, delays may be specified for non-SMTP input, where smtp_out and
3391 smtp_in will be NULL. Whatever is done must work in all cases.
3392
3393 NOTE 2: The added feature of flushing the output before a delay must
3394 apply only to SMTP input. Hence the test for smtp_out being non-NULL.
3395 */
3396
3397 else
3398 {
3399 if (smtp_out && !f.disable_delay_flush)
3400 mac_smtp_fflush();
3401
3402 #if !defined(NO_POLL_H) && defined (POLLRDHUP)
3403 {
3404 struct pollfd p;
3405 nfds_t n = 0;
3406 if (smtp_out)
3407 {
3408 p.fd = fileno(smtp_out);
3409 p.events = POLLRDHUP;
3410 n = 1;
3411 }
3412 if (poll(&p, n, delay*1000) > 0)
3413 HDEBUG(D_acl) debug_printf_indent("delay cancelled by peer close\n");
3414 }
3415 #else
3416 /* Lacking POLLRDHUP it appears to be impossible to detect that a
3417 TCP/IP connection has gone away without reading from it. This means
3418 that we cannot shorten the delay below if the client goes away,
3419 because we cannot discover that the client has closed its end of the
3420 connection. (The connection is actually in a half-closed state,
3421 waiting for the server to close its end.) It would be nice to be able
3422 to detect this state, so that the Exim process is not held up
3423 unnecessarily. However, it seems that we can't. The poll() function
3424 does not do the right thing, and in any case it is not always
3425 available. */
3426
3427 while (delay > 0) delay = sleep(delay);
3428 #endif
3429 }
3430 }
3431 }
3432 break;
3433
3434 #ifndef DISABLE_DKIM
3435 case ACLC_DKIM_SIGNER:
3436 if (dkim_cur_signer)
3437 rc = match_isinlist(dkim_cur_signer,
3438 &arg,0,NULL,NULL,MCL_STRING,TRUE,NULL);
3439 else
3440 rc = FAIL;
3441 break;
3442
3443 case ACLC_DKIM_STATUS:
3444 rc = match_isinlist(dkim_verify_status,
3445 &arg,0,NULL,NULL,MCL_STRING,TRUE,NULL);
3446 break;
3447 #endif
3448
3449 #ifdef SUPPORT_DMARC
3450 case ACLC_DMARC_STATUS:
3451 if (!f.dmarc_has_been_checked)
3452 dmarc_process();
3453 f.dmarc_has_been_checked = TRUE;
3454 /* used long way of dmarc_exim_expand_query() in case we need more
3455 * view into the process in the future. */
3456 rc = match_isinlist(dmarc_exim_expand_query(DMARC_VERIFY_STATUS),
3457 &arg,0,NULL,NULL,MCL_STRING,TRUE,NULL);
3458 break;
3459 #endif