tidying
[exim.git] / src / src / acl.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2016 */
6 /* See the file NOTICE for conditions of use and distribution. */
7
8 /* Code for handling Access Control Lists (ACLs) */
9
10 #include "exim.h"
11
12
13 /* Default callout timeout */
14
15 #define CALLOUT_TIMEOUT_DEFAULT 30
16
17 /* ACL verb codes - keep in step with the table of verbs that follows */
18
19 enum { ACL_ACCEPT, ACL_DEFER, ACL_DENY, ACL_DISCARD, ACL_DROP, ACL_REQUIRE,
20 ACL_WARN };
21
22 /* ACL verbs */
23
24 static uschar *verbs[] = {
25 US"accept",
26 US"defer",
27 US"deny",
28 US"discard",
29 US"drop",
30 US"require",
31 US"warn" };
32
33 /* For each verb, the conditions for which "message" or "log_message" are used
34 are held as a bitmap. This is to avoid expanding the strings unnecessarily. For
35 "accept", the FAIL case is used only after "endpass", but that is selected in
36 the code. */
37
38 static int msgcond[] = {
39 (1<<OK) | (1<<FAIL) | (1<<FAIL_DROP), /* accept */
40 (1<<OK), /* defer */
41 (1<<OK), /* deny */
42 (1<<OK) | (1<<FAIL) | (1<<FAIL_DROP), /* discard */
43 (1<<OK), /* drop */
44 (1<<FAIL) | (1<<FAIL_DROP), /* require */
45 (1<<OK) /* warn */
46 };
47
48 /* ACL condition and modifier codes - keep in step with the table that
49 follows.
50 down. */
51
52 enum { ACLC_ACL,
53 ACLC_ADD_HEADER,
54 ACLC_AUTHENTICATED,
55 #ifdef EXPERIMENTAL_BRIGHTMAIL
56 ACLC_BMI_OPTIN,
57 #endif
58 ACLC_CONDITION,
59 ACLC_CONTINUE,
60 ACLC_CONTROL,
61 #ifdef EXPERIMENTAL_DCC
62 ACLC_DCC,
63 #endif
64 #ifdef WITH_CONTENT_SCAN
65 ACLC_DECODE,
66 #endif
67 ACLC_DELAY,
68 #ifndef DISABLE_DKIM
69 ACLC_DKIM_SIGNER,
70 ACLC_DKIM_STATUS,
71 #endif
72 #ifdef EXPERIMENTAL_DMARC
73 ACLC_DMARC_STATUS,
74 #endif
75 ACLC_DNSLISTS,
76 ACLC_DOMAINS,
77 ACLC_ENCRYPTED,
78 ACLC_ENDPASS,
79 ACLC_HOSTS,
80 ACLC_LOCAL_PARTS,
81 ACLC_LOG_MESSAGE,
82 ACLC_LOG_REJECT_TARGET,
83 ACLC_LOGWRITE,
84 #ifdef WITH_CONTENT_SCAN
85 ACLC_MALWARE,
86 #endif
87 ACLC_MESSAGE,
88 #ifdef WITH_CONTENT_SCAN
89 ACLC_MIME_REGEX,
90 #endif
91 ACLC_QUEUE,
92 ACLC_RATELIMIT,
93 ACLC_RECIPIENTS,
94 #ifdef WITH_CONTENT_SCAN
95 ACLC_REGEX,
96 #endif
97 ACLC_REMOVE_HEADER,
98 ACLC_SENDER_DOMAINS,
99 ACLC_SENDERS,
100 ACLC_SET,
101 #ifdef WITH_CONTENT_SCAN
102 ACLC_SPAM,
103 #endif
104 #ifdef EXPERIMENTAL_SPF
105 ACLC_SPF,
106 ACLC_SPF_GUESS,
107 #endif
108 ACLC_UDPSEND,
109 ACLC_VERIFY };
110
111 /* ACL conditions/modifiers: "delay", "control", "continue", "endpass",
112 "message", "log_message", "log_reject_target", "logwrite", "queue" and "set" are
113 modifiers that look like conditions but always return TRUE. They are used for
114 their side effects. */
115
116 typedef struct condition_def {
117 uschar *name;
118
119 /* Flag to indicate the condition/modifier has a string expansion done
120 at the outer level. In the other cases, expansion already occurs in the
121 checking functions. */
122 BOOL expand_at_top:1;
123
124 BOOL is_modifier:1;
125
126 /* Bit map vector of which conditions and modifiers are not allowed at certain
127 times. For each condition and modifier, there's a bitmap of dis-allowed times.
128 For some, it is easier to specify the negation of a small number of allowed
129 times. */
130 unsigned forbids;
131
132 } condition_def;
133
134 static condition_def conditions[] = {
135 { US"acl", FALSE, FALSE, 0 },
136
137 { US"add_header", TRUE, TRUE,
138 (unsigned int)
139 ~((1<<ACL_WHERE_MAIL)|(1<<ACL_WHERE_RCPT)|
140 (1<<ACL_WHERE_PREDATA)|(1<<ACL_WHERE_DATA)|
141 #ifndef DISABLE_PRDR
142 (1<<ACL_WHERE_PRDR)|
143 #endif
144 (1<<ACL_WHERE_MIME)|(1<<ACL_WHERE_NOTSMTP)|
145 (1<<ACL_WHERE_DKIM)|
146 (1<<ACL_WHERE_NOTSMTP_START)),
147 },
148
149 { US"authenticated", FALSE, FALSE,
150 (1<<ACL_WHERE_NOTSMTP)|
151 (1<<ACL_WHERE_NOTSMTP_START)|
152 (1<<ACL_WHERE_CONNECT)|(1<<ACL_WHERE_HELO),
153 },
154 #ifdef EXPERIMENTAL_BRIGHTMAIL
155 { US"bmi_optin", TRUE, TRUE,
156 (1<<ACL_WHERE_AUTH)|
157 (1<<ACL_WHERE_CONNECT)|(1<<ACL_WHERE_HELO)|
158 (1<<ACL_WHERE_DATA)|(1<<ACL_WHERE_MIME)|
159 # ifndef DISABLE_PRDR
160 (1<<ACL_WHERE_PRDR)|
161 # endif
162 (1<<ACL_WHERE_ETRN)|(1<<ACL_WHERE_EXPN)|
163 (1<<ACL_WHERE_MAILAUTH)|
164 (1<<ACL_WHERE_MAIL)|(1<<ACL_WHERE_STARTTLS)|
165 (1<<ACL_WHERE_VRFY)|(1<<ACL_WHERE_PREDATA)|
166 (1<<ACL_WHERE_NOTSMTP_START),
167 },
168 #endif
169 { US"condition", TRUE, FALSE, 0 },
170 { US"continue", TRUE, TRUE, 0 },
171
172 /* Certain types of control are always allowed, so we let it through
173 always and check in the control processing itself. */
174 { US"control", TRUE, TRUE, 0 },
175
176 #ifdef EXPERIMENTAL_DCC
177 { US"dcc", TRUE, FALSE,
178 (unsigned int)
179 ~((1<<ACL_WHERE_DATA)|
180 # ifndef DISABLE_PRDR
181 (1<<ACL_WHERE_PRDR)|
182 # endif
183 (1<<ACL_WHERE_NOTSMTP)),
184 },
185 #endif
186 #ifdef WITH_CONTENT_SCAN
187 { US"decode", TRUE, FALSE, (unsigned int) ~(1<<ACL_WHERE_MIME) },
188
189 #endif
190 { US"delay", TRUE, TRUE, (1<<ACL_WHERE_NOTQUIT) },
191 #ifndef DISABLE_DKIM
192 { US"dkim_signers", TRUE, FALSE, (unsigned int) ~(1<<ACL_WHERE_DKIM) },
193 { US"dkim_status", TRUE, FALSE, (unsigned int) ~(1<<ACL_WHERE_DKIM) },
194 #endif
195 #ifdef EXPERIMENTAL_DMARC
196 { US"dmarc_status", TRUE, FALSE, (unsigned int) ~(1<<ACL_WHERE_DATA) },
197 #endif
198
199 /* Explicit key lookups can be made in non-smtp ACLs so pass
200 always and check in the verify processing itself. */
201 { US"dnslists", TRUE, FALSE, 0 },
202
203 { US"domains", FALSE, FALSE,
204 (unsigned int)
205 ~((1<<ACL_WHERE_RCPT)
206 |(1<<ACL_WHERE_VRFY)
207 #ifndef DISABLE_PRDR
208 |(1<<ACL_WHERE_PRDR)
209 #endif
210 ),
211 },
212 { US"encrypted", FALSE, FALSE,
213 (1<<ACL_WHERE_NOTSMTP)|
214 (1<<ACL_WHERE_CONNECT)|
215 (1<<ACL_WHERE_NOTSMTP_START)|
216 (1<<ACL_WHERE_HELO),
217 },
218
219 { US"endpass", TRUE, TRUE, 0 },
220
221 { US"hosts", FALSE, FALSE,
222 (1<<ACL_WHERE_NOTSMTP)|
223 (1<<ACL_WHERE_NOTSMTP_START),
224 },
225 { US"local_parts", FALSE, FALSE,
226 (unsigned int)
227 ~((1<<ACL_WHERE_RCPT)
228 |(1<<ACL_WHERE_VRFY)
229 #ifndef DISABLE_PRDR
230 |(1<<ACL_WHERE_PRDR)
231 #endif
232 ),
233 },
234
235 { US"log_message", TRUE, TRUE, 0 },
236 { US"log_reject_target", TRUE, TRUE, 0 },
237 { US"logwrite", TRUE, TRUE, 0 },
238
239 #ifdef WITH_CONTENT_SCAN
240 { US"malware", TRUE, FALSE,
241 (unsigned int)
242 ~((1<<ACL_WHERE_DATA)|
243 # ifndef DISABLE_PRDR
244 (1<<ACL_WHERE_PRDR)|
245 # endif
246 (1<<ACL_WHERE_NOTSMTP)),
247 },
248 #endif
249
250 { US"message", TRUE, TRUE, 0 },
251 #ifdef WITH_CONTENT_SCAN
252 { US"mime_regex", TRUE, FALSE, (unsigned int) ~(1<<ACL_WHERE_MIME) },
253 #endif
254
255 { US"queue", TRUE, TRUE,
256 (1<<ACL_WHERE_NOTSMTP)|
257 #ifndef DISABLE_PRDR
258 (1<<ACL_WHERE_PRDR)|
259 #endif
260 (1<<ACL_WHERE_DATA),
261 },
262
263 { US"ratelimit", TRUE, FALSE, 0 },
264 { US"recipients", FALSE, FALSE, (unsigned int) ~(1<<ACL_WHERE_RCPT) },
265
266 #ifdef WITH_CONTENT_SCAN
267 { US"regex", TRUE, FALSE,
268 (unsigned int)
269 ~((1<<ACL_WHERE_DATA)|
270 # ifndef DISABLE_PRDR
271 (1<<ACL_WHERE_PRDR)|
272 # endif
273 (1<<ACL_WHERE_NOTSMTP)|
274 (1<<ACL_WHERE_MIME)),
275 },
276
277 #endif
278 { US"remove_header", TRUE, TRUE,
279 (unsigned int)
280 ~((1<<ACL_WHERE_MAIL)|(1<<ACL_WHERE_RCPT)|
281 (1<<ACL_WHERE_PREDATA)|(1<<ACL_WHERE_DATA)|
282 #ifndef DISABLE_PRDR
283 (1<<ACL_WHERE_PRDR)|
284 #endif
285 (1<<ACL_WHERE_MIME)|(1<<ACL_WHERE_NOTSMTP)|
286 (1<<ACL_WHERE_NOTSMTP_START)),
287 },
288 { US"sender_domains", FALSE, FALSE,
289 (1<<ACL_WHERE_AUTH)|(1<<ACL_WHERE_CONNECT)|
290 (1<<ACL_WHERE_HELO)|
291 (1<<ACL_WHERE_MAILAUTH)|(1<<ACL_WHERE_QUIT)|
292 (1<<ACL_WHERE_ETRN)|(1<<ACL_WHERE_EXPN)|
293 (1<<ACL_WHERE_STARTTLS)|(1<<ACL_WHERE_VRFY),
294 },
295 { US"senders", FALSE, FALSE,
296 (1<<ACL_WHERE_AUTH)|(1<<ACL_WHERE_CONNECT)|
297 (1<<ACL_WHERE_HELO)|
298 (1<<ACL_WHERE_MAILAUTH)|(1<<ACL_WHERE_QUIT)|
299 (1<<ACL_WHERE_ETRN)|(1<<ACL_WHERE_EXPN)|
300 (1<<ACL_WHERE_STARTTLS)|(1<<ACL_WHERE_VRFY),
301 },
302
303 { US"set", TRUE, TRUE, 0 },
304
305 #ifdef WITH_CONTENT_SCAN
306 { US"spam", TRUE, FALSE,
307 (unsigned int)
308 ~((1<<ACL_WHERE_DATA)|
309 # ifndef DISABLE_PRDR
310 (1<<ACL_WHERE_PRDR)|
311 # endif
312 (1<<ACL_WHERE_NOTSMTP)),
313 },
314 #endif
315 #ifdef EXPERIMENTAL_SPF
316 { US"spf", TRUE, FALSE,
317 (1<<ACL_WHERE_AUTH)|(1<<ACL_WHERE_CONNECT)|
318 (1<<ACL_WHERE_HELO)|
319 (1<<ACL_WHERE_MAILAUTH)|
320 (1<<ACL_WHERE_ETRN)|(1<<ACL_WHERE_EXPN)|
321 (1<<ACL_WHERE_STARTTLS)|(1<<ACL_WHERE_VRFY)|
322 (1<<ACL_WHERE_NOTSMTP)|
323 (1<<ACL_WHERE_NOTSMTP_START),
324 },
325 { US"spf_guess", TRUE, FALSE,
326 (1<<ACL_WHERE_AUTH)|(1<<ACL_WHERE_CONNECT)|
327 (1<<ACL_WHERE_HELO)|
328 (1<<ACL_WHERE_MAILAUTH)|
329 (1<<ACL_WHERE_ETRN)|(1<<ACL_WHERE_EXPN)|
330 (1<<ACL_WHERE_STARTTLS)|(1<<ACL_WHERE_VRFY)|
331 (1<<ACL_WHERE_NOTSMTP)|
332 (1<<ACL_WHERE_NOTSMTP_START),
333 },
334 #endif
335 { US"udpsend", TRUE, TRUE, 0 },
336
337 /* Certain types of verify are always allowed, so we let it through
338 always and check in the verify function itself */
339 { US"verify", TRUE, FALSE,
340 0
341 },
342 };
343
344
345
346 /* Return values from decode_control(); used as index so keep in step
347 with the controls_list table that follows! */
348
349 enum {
350 CONTROL_AUTH_UNADVERTISED,
351 #ifdef EXPERIMENTAL_BRIGHTMAIL
352 CONTROL_BMI_RUN,
353 #endif
354 CONTROL_CASEFUL_LOCAL_PART,
355 CONTROL_CASELOWER_LOCAL_PART,
356 CONTROL_CUTTHROUGH_DELIVERY,
357 CONTROL_DEBUG,
358 #ifndef DISABLE_DKIM
359 CONTROL_DKIM_VERIFY,
360 #endif
361 #ifdef EXPERIMENTAL_DMARC
362 CONTROL_DMARC_VERIFY,
363 CONTROL_DMARC_FORENSIC,
364 #endif
365 CONTROL_DSCP,
366 CONTROL_ENFORCE_SYNC,
367 CONTROL_ERROR, /* pseudo-value for decode errors */
368 CONTROL_FAKEDEFER,
369 CONTROL_FAKEREJECT,
370 CONTROL_FREEZE,
371
372 CONTROL_NO_CALLOUT_FLUSH,
373 CONTROL_NO_DELAY_FLUSH,
374 CONTROL_NO_ENFORCE_SYNC,
375 #ifdef WITH_CONTENT_SCAN
376 CONTROL_NO_MBOX_UNSPOOL,
377 #endif
378 CONTROL_NO_MULTILINE,
379 CONTROL_NO_PIPELINING,
380
381 CONTROL_QUEUE_ONLY,
382 CONTROL_SUBMISSION,
383 CONTROL_SUPPRESS_LOCAL_FIXUPS,
384 #ifdef SUPPORT_I18N
385 CONTROL_UTF8_DOWNCONVERT,
386 #endif
387 };
388
389
390
391 /* Structure listing various control arguments, with their characteristics.
392 For each control, there's a bitmap of dis-allowed times. For some, it is easier
393 to specify the negation of a small number of allowed times. */
394
395 typedef struct control_def {
396 uschar *name;
397 BOOL has_option; /* Has /option(s) following */
398 unsigned forbids; /* bitmap of dis-allowed times */
399 } control_def;
400
401 static control_def controls_list[] = {
402 { US"allow_auth_unadvertised", FALSE,
403 (unsigned)
404 ~((1<<ACL_WHERE_CONNECT)|(1<<ACL_WHERE_HELO))
405 },
406 #ifdef EXPERIMENTAL_BRIGHTMAIL
407 { US"bmi_run", FALSE, 0 },
408 #endif
409 { US"caseful_local_part", FALSE, (unsigned) ~(1<<ACL_WHERE_RCPT) },
410 { US"caselower_local_part", FALSE, (unsigned) ~(1<<ACL_WHERE_RCPT) },
411 { US"cutthrough_delivery", TRUE, 0 },
412 { US"debug", TRUE, 0 },
413
414 #ifndef DISABLE_DKIM
415 { US"dkim_disable_verify", FALSE,
416 (1<<ACL_WHERE_DATA)|(1<<ACL_WHERE_NOTSMTP)|
417 # ifndef DISABLE_PRDR
418 (1<<ACL_WHERE_PRDR)|
419 # endif
420 (1<<ACL_WHERE_NOTSMTP_START)
421 },
422 #endif
423
424 #ifdef EXPERIMENTAL_DMARC
425 { US"dmarc_disable_verify", FALSE,
426 (1<<ACL_WHERE_DATA)|(1<<ACL_WHERE_NOTSMTP)|(1<<ACL_WHERE_NOTSMTP_START)
427 },
428 { US"dmarc_enable_forensic", FALSE,
429 (1<<ACL_WHERE_DATA)|(1<<ACL_WHERE_NOTSMTP)|(1<<ACL_WHERE_NOTSMTP_START)
430 },
431 #endif
432
433 { US"dscp", TRUE,
434 (1<<ACL_WHERE_NOTSMTP)|(1<<ACL_WHERE_NOTSMTP_START)|(1<<ACL_WHERE_NOTQUIT)
435 },
436 { US"enforce_sync", FALSE,
437 (1<<ACL_WHERE_NOTSMTP)|(1<<ACL_WHERE_NOTSMTP_START)
438 },
439
440 /* Pseudo-value for decode errors */
441 { US"error", FALSE, 0 },
442
443 { US"fakedefer", TRUE,
444 (unsigned)
445 ~((1<<ACL_WHERE_MAIL)|(1<<ACL_WHERE_RCPT)|
446 (1<<ACL_WHERE_PREDATA)|(1<<ACL_WHERE_DATA)|
447 #ifndef DISABLE_PRDR
448 (1<<ACL_WHERE_PRDR)|
449 #endif
450 (1<<ACL_WHERE_MIME))
451 },
452 { US"fakereject", TRUE,
453 (unsigned)
454 ~((1<<ACL_WHERE_MAIL)|(1<<ACL_WHERE_RCPT)|
455 (1<<ACL_WHERE_PREDATA)|(1<<ACL_WHERE_DATA)|
456 #ifndef DISABLE_PRDR
457 (1<<ACL_WHERE_PRDR)|
458 #endif
459 (1<<ACL_WHERE_MIME))
460 },
461 { US"freeze", TRUE,
462 (unsigned)
463 ~((1<<ACL_WHERE_MAIL)|(1<<ACL_WHERE_RCPT)|
464 (1<<ACL_WHERE_PREDATA)|(1<<ACL_WHERE_DATA)|
465 // (1<<ACL_WHERE_PRDR)| /* Not allow one user to freeze for all */
466 (1<<ACL_WHERE_NOTSMTP)|(1<<ACL_WHERE_MIME))
467 },
468
469 { US"no_callout_flush", FALSE,
470 (1<<ACL_WHERE_NOTSMTP)| (1<<ACL_WHERE_NOTSMTP_START)
471 },
472 { US"no_delay_flush", FALSE,
473 (1<<ACL_WHERE_NOTSMTP)|(1<<ACL_WHERE_NOTSMTP_START)
474 },
475
476 { US"no_enforce_sync", FALSE,
477 (1<<ACL_WHERE_NOTSMTP)|(1<<ACL_WHERE_NOTSMTP_START)
478 },
479 #ifdef WITH_CONTENT_SCAN
480 { US"no_mbox_unspool", FALSE,
481 (unsigned)
482 ~((1<<ACL_WHERE_MAIL)|(1<<ACL_WHERE_RCPT)|
483 (1<<ACL_WHERE_PREDATA)|(1<<ACL_WHERE_DATA)|
484 // (1<<ACL_WHERE_PRDR)| /* Not allow one user to freeze for all */
485 (1<<ACL_WHERE_MIME))
486 },
487 #endif
488 { US"no_multiline_responses", FALSE,
489 (1<<ACL_WHERE_NOTSMTP)|(1<<ACL_WHERE_NOTSMTP_START)
490 },
491 { US"no_pipelining", FALSE,
492 (1<<ACL_WHERE_NOTSMTP)|(1<<ACL_WHERE_NOTSMTP_START)
493 },
494
495 { US"queue_only", FALSE,
496 (unsigned)
497 ~((1<<ACL_WHERE_MAIL)|(1<<ACL_WHERE_RCPT)|
498 (1<<ACL_WHERE_PREDATA)|(1<<ACL_WHERE_DATA)|
499 // (1<<ACL_WHERE_PRDR)| /* Not allow one user to freeze for all */
500 (1<<ACL_WHERE_NOTSMTP)|(1<<ACL_WHERE_MIME))
501 },
502 { US"submission", TRUE,
503 (unsigned)
504 ~((1<<ACL_WHERE_MAIL)|(1<<ACL_WHERE_RCPT)|(1<<ACL_WHERE_PREDATA))
505 },
506 { US"suppress_local_fixups", FALSE,
507 (unsigned)
508 ~((1<<ACL_WHERE_MAIL)|(1<<ACL_WHERE_RCPT)|(1<<ACL_WHERE_PREDATA)|
509 (1<<ACL_WHERE_NOTSMTP_START))
510 },
511 #ifdef SUPPORT_I18N
512 { US"utf8_downconvert", TRUE, 0 }
513 #endif
514 };
515
516 /* Support data structures for Client SMTP Authorization. acl_verify_csa()
517 caches its result in a tree to avoid repeated DNS queries. The result is an
518 integer code which is used as an index into the following tables of
519 explanatory strings and verification return codes. */
520
521 static tree_node *csa_cache = NULL;
522
523 enum { CSA_UNKNOWN, CSA_OK, CSA_DEFER_SRV, CSA_DEFER_ADDR,
524 CSA_FAIL_EXPLICIT, CSA_FAIL_DOMAIN, CSA_FAIL_NOADDR, CSA_FAIL_MISMATCH };
525
526 /* The acl_verify_csa() return code is translated into an acl_verify() return
527 code using the following table. It is OK unless the client is definitely not
528 authorized. This is because CSA is supposed to be optional for sending sites,
529 so recipients should not be too strict about checking it - especially because
530 DNS problems are quite likely to occur. It's possible to use $csa_status in
531 further ACL conditions to distinguish ok, unknown, and defer if required, but
532 the aim is to make the usual configuration simple. */
533
534 static int csa_return_code[] = {
535 OK, OK, OK, OK,
536 FAIL, FAIL, FAIL, FAIL
537 };
538
539 static uschar *csa_status_string[] = {
540 US"unknown", US"ok", US"defer", US"defer",
541 US"fail", US"fail", US"fail", US"fail"
542 };
543
544 static uschar *csa_reason_string[] = {
545 US"unknown",
546 US"ok",
547 US"deferred (SRV lookup failed)",
548 US"deferred (target address lookup failed)",
549 US"failed (explicit authorization required)",
550 US"failed (host name not authorized)",
551 US"failed (no authorized addresses)",
552 US"failed (client address mismatch)"
553 };
554
555 /* Options for the ratelimit condition. Note that there are two variants of
556 the per_rcpt option, depending on the ACL that is used to measure the rate.
557 However any ACL must be able to look up per_rcpt rates in /noupdate mode,
558 so the two variants must have the same internal representation as well as
559 the same configuration string. */
560
561 enum {
562 RATE_PER_WHAT, RATE_PER_CLASH, RATE_PER_ADDR, RATE_PER_BYTE, RATE_PER_CMD,
563 RATE_PER_CONN, RATE_PER_MAIL, RATE_PER_RCPT, RATE_PER_ALLRCPTS
564 };
565
566 #define RATE_SET(var,new) \
567 (((var) == RATE_PER_WHAT) ? ((var) = RATE_##new) : ((var) = RATE_PER_CLASH))
568
569 static uschar *ratelimit_option_string[] = {
570 US"?", US"!", US"per_addr", US"per_byte", US"per_cmd",
571 US"per_conn", US"per_mail", US"per_rcpt", US"per_rcpt"
572 };
573
574 /* Enable recursion between acl_check_internal() and acl_check_condition() */
575
576 static int acl_check_wargs(int, address_item *, const uschar *, uschar **,
577 uschar **);
578
579
580 /*************************************************
581 * Find control in list *
582 *************************************************/
583
584 /* The lists are always in order, so binary chop can be used.
585
586 Arguments:
587 name the control name to search for
588 ol the first entry in the control list
589 last one more than the offset of the last entry in the control list
590
591 Returns: index of a control entry, or -1 if not found
592 */
593
594 static int
595 find_control(const uschar * name, control_def * ol, int last)
596 {
597 int first = 0;
598 while (last > first)
599 {
600 int middle = (first + last)/2;
601 uschar * s = ol[middle].name;
602 int c = Ustrncmp(name, s, Ustrlen(s));
603 if (c == 0) return middle;
604 else if (c > 0) first = middle + 1;
605 else last = middle;
606 }
607 return -1;
608 }
609
610
611
612 /*************************************************
613 * Pick out condition from list *
614 *************************************************/
615
616 /* Use a binary chop method
617
618 Arguments:
619 name name to find
620 list list of conditions
621 end size of list
622
623 Returns: offset in list, or -1 if not found
624 */
625
626 static int
627 acl_checkcondition(uschar * name, condition_def * list, int end)
628 {
629 int start = 0;
630 while (start < end)
631 {
632 int mid = (start + end)/2;
633 int c = Ustrcmp(name, list[mid].name);
634 if (c == 0) return mid;
635 if (c < 0) end = mid;
636 else start = mid + 1;
637 }
638 return -1;
639 }
640
641
642 /*************************************************
643 * Pick out name from list *
644 *************************************************/
645
646 /* Use a binary chop method
647
648 Arguments:
649 name name to find
650 list list of names
651 end size of list
652
653 Returns: offset in list, or -1 if not found
654 */
655
656 static int
657 acl_checkname(uschar *name, uschar **list, int end)
658 {
659 int start = 0;
660
661 while (start < end)
662 {
663 int mid = (start + end)/2;
664 int c = Ustrcmp(name, list[mid]);
665 if (c == 0) return mid;
666 if (c < 0) end = mid; else start = mid + 1;
667 }
668
669 return -1;
670 }
671
672
673 /*************************************************
674 * Read and parse one ACL *
675 *************************************************/
676
677 /* This function is called both from readconf in order to parse the ACLs in the
678 configuration file, and also when an ACL is encountered dynamically (e.g. as
679 the result of an expansion). It is given a function to call in order to
680 retrieve the lines of the ACL. This function handles skipping comments and
681 blank lines (where relevant).
682
683 Arguments:
684 func function to get next line of ACL
685 error where to put an error message
686
687 Returns: pointer to ACL, or NULL
688 NULL can be legal (empty ACL); in this case error will be NULL
689 */
690
691 acl_block *
692 acl_read(uschar *(*func)(void), uschar **error)
693 {
694 acl_block *yield = NULL;
695 acl_block **lastp = &yield;
696 acl_block *this = NULL;
697 acl_condition_block *cond;
698 acl_condition_block **condp = NULL;
699 uschar *s;
700
701 *error = NULL;
702
703 while ((s = (*func)()) != NULL)
704 {
705 int v, c;
706 BOOL negated = FALSE;
707 uschar *saveline = s;
708 uschar name[64];
709
710 /* Conditions (but not verbs) are allowed to be negated by an initial
711 exclamation mark. */
712
713 while (isspace(*s)) s++;
714 if (*s == '!')
715 {
716 negated = TRUE;
717 s++;
718 }
719
720 /* Read the name of a verb or a condition, or the start of a new ACL, which
721 can be started by a name, or by a macro definition. */
722
723 s = readconf_readname(name, sizeof(name), s);
724 if (*s == ':' || (isupper(name[0]) && *s == '=')) return yield;
725
726 /* If a verb is unrecognized, it may be another condition or modifier that
727 continues the previous verb. */
728
729 if ((v = acl_checkname(name, verbs, nelem(verbs))) < 0)
730 {
731 if (this == NULL)
732 {
733 *error = string_sprintf("unknown ACL verb \"%s\" in \"%s\"", name,
734 saveline);
735 return NULL;
736 }
737 }
738
739 /* New verb */
740
741 else
742 {
743 if (negated)
744 {
745 *error = string_sprintf("malformed ACL line \"%s\"", saveline);
746 return NULL;
747 }
748 this = store_get(sizeof(acl_block));
749 *lastp = this;
750 lastp = &(this->next);
751 this->next = NULL;
752 this->verb = v;
753 this->condition = NULL;
754 condp = &(this->condition);
755 if (*s == 0) continue; /* No condition on this line */
756 if (*s == '!')
757 {
758 negated = TRUE;
759 s++;
760 }
761 s = readconf_readname(name, sizeof(name), s); /* Condition name */
762 }
763
764 /* Handle a condition or modifier. */
765
766 if ((c = acl_checkcondition(name, conditions, nelem(conditions))) < 0)
767 {
768 *error = string_sprintf("unknown ACL condition/modifier in \"%s\"",
769 saveline);
770 return NULL;
771 }
772
773 /* The modifiers may not be negated */
774
775 if (negated && conditions[c].is_modifier)
776 {
777 *error = string_sprintf("ACL error: negation is not allowed with "
778 "\"%s\"", conditions[c].name);
779 return NULL;
780 }
781
782 /* ENDPASS may occur only with ACCEPT or DISCARD. */
783
784 if (c == ACLC_ENDPASS &&
785 this->verb != ACL_ACCEPT &&
786 this->verb != ACL_DISCARD)
787 {
788 *error = string_sprintf("ACL error: \"%s\" is not allowed with \"%s\"",
789 conditions[c].name, verbs[this->verb]);
790 return NULL;
791 }
792
793 cond = store_get(sizeof(acl_condition_block));
794 cond->next = NULL;
795 cond->type = c;
796 cond->u.negated = negated;
797
798 *condp = cond;
799 condp = &(cond->next);
800
801 /* The "set" modifier is different in that its argument is "name=value"
802 rather than just a value, and we can check the validity of the name, which
803 gives us a variable name to insert into the data block. The original ACL
804 variable names were acl_c0 ... acl_c9 and acl_m0 ... acl_m9. This was
805 extended to 20 of each type, but after that people successfully argued for
806 arbitrary names. In the new scheme, the names must start with acl_c or acl_m.
807 After that, we allow alphanumerics and underscores, but the first character
808 after c or m must be a digit or an underscore. This retains backwards
809 compatibility. */
810
811 if (c == ACLC_SET)
812 {
813 uschar *endptr;
814
815 if (Ustrncmp(s, "acl_c", 5) != 0 &&
816 Ustrncmp(s, "acl_m", 5) != 0)
817 {
818 *error = string_sprintf("invalid variable name after \"set\" in ACL "
819 "modifier \"set %s\" (must start \"acl_c\" or \"acl_m\")", s);
820 return NULL;
821 }
822
823 endptr = s + 5;
824 if (!isdigit(*endptr) && *endptr != '_')
825 {
826 *error = string_sprintf("invalid variable name after \"set\" in ACL "
827 "modifier \"set %s\" (digit or underscore must follow acl_c or acl_m)",
828 s);
829 return NULL;
830 }
831
832 while (*endptr != 0 && *endptr != '=' && !isspace(*endptr))
833 {
834 if (!isalnum(*endptr) && *endptr != '_')
835 {
836 *error = string_sprintf("invalid character \"%c\" in variable name "
837 "in ACL modifier \"set %s\"", *endptr, s);
838 return NULL;
839 }
840 endptr++;
841 }
842
843 cond->u.varname = string_copyn(s + 4, endptr - s - 4);
844 s = endptr;
845 while (isspace(*s)) s++;
846 }
847
848 /* For "set", we are now positioned for the data. For the others, only
849 "endpass" has no data */
850
851 if (c != ACLC_ENDPASS)
852 {
853 if (*s++ != '=')
854 {
855 *error = string_sprintf("\"=\" missing after ACL \"%s\" %s", name,
856 conditions[c].is_modifier ? US"modifier" : US"condition");
857 return NULL;
858 }
859 while (isspace(*s)) s++;
860 cond->arg = string_copy(s);
861 }
862 }
863
864 return yield;
865 }
866
867
868
869 /*************************************************
870 * Set up added header line(s) *
871 *************************************************/
872
873 /* This function is called by the add_header modifier, and also from acl_warn()
874 to implement the now-deprecated way of adding header lines using "message" on a
875 "warn" verb. The argument is treated as a sequence of header lines which are
876 added to a chain, provided there isn't an identical one already there.
877
878 Argument: string of header lines
879 Returns: nothing
880 */
881
882 static void
883 setup_header(const uschar *hstring)
884 {
885 const uschar *p, *q;
886 int hlen = Ustrlen(hstring);
887
888 /* Ignore any leading newlines */
889 while (*hstring == '\n') hstring++, hlen--;
890
891 /* An empty string does nothing; ensure exactly one final newline. */
892 if (hlen <= 0) return;
893 if (hstring[--hlen] != '\n') /* no newline */
894 q = string_sprintf("%s\n", hstring);
895 else if (hstring[hlen-1] == '\n') /* double newline */
896 {
897 uschar * s = string_copy(hstring);
898 while(s[--hlen] == '\n')
899 s[hlen+1] = '\0';
900 q = s;
901 }
902 else
903 q = hstring;
904
905 /* Loop for multiple header lines, taking care about continuations */
906
907 for (p = q; *p != 0; )
908 {
909 const uschar *s;
910 uschar * hdr;
911 int newtype = htype_add_bot;
912 header_line **hptr = &acl_added_headers;
913
914 /* Find next header line within the string */
915
916 for (;;)
917 {
918 q = Ustrchr(q, '\n'); /* we know there was a newline */
919 if (*(++q) != ' ' && *q != '\t') break;
920 }
921
922 /* If the line starts with a colon, interpret the instruction for where to
923 add it. This temporarily sets up a new type. */
924
925 if (*p == ':')
926 {
927 if (strncmpic(p, US":after_received:", 16) == 0)
928 {
929 newtype = htype_add_rec;
930 p += 16;
931 }
932 else if (strncmpic(p, US":at_start_rfc:", 14) == 0)
933 {
934 newtype = htype_add_rfc;
935 p += 14;
936 }
937 else if (strncmpic(p, US":at_start:", 10) == 0)
938 {
939 newtype = htype_add_top;
940 p += 10;
941 }
942 else if (strncmpic(p, US":at_end:", 8) == 0)
943 {
944 newtype = htype_add_bot;
945 p += 8;
946 }
947 while (*p == ' ' || *p == '\t') p++;
948 }
949
950 /* See if this line starts with a header name, and if not, add X-ACL-Warn:
951 to the front of it. */
952
953 for (s = p; s < q - 1; s++)
954 {
955 if (*s == ':' || !isgraph(*s)) break;
956 }
957
958 hdr = string_sprintf("%s%.*s", (*s == ':')? "" : "X-ACL-Warn: ", (int) (q - p), p);
959 hlen = Ustrlen(hdr);
960
961 /* See if this line has already been added */
962
963 while (*hptr != NULL)
964 {
965 if (Ustrncmp((*hptr)->text, hdr, hlen) == 0) break;
966 hptr = &((*hptr)->next);
967 }
968
969 /* Add if not previously present */
970
971 if (*hptr == NULL)
972 {
973 header_line *h = store_get(sizeof(header_line));
974 h->text = hdr;
975 h->next = NULL;
976 h->type = newtype;
977 h->slen = hlen;
978 *hptr = h;
979 hptr = &(h->next);
980 }
981
982 /* Advance for next header line within the string */
983
984 p = q;
985 }
986 }
987
988
989
990 /*************************************************
991 * List the added header lines *
992 *************************************************/
993 uschar *
994 fn_hdrs_added(void)
995 {
996 uschar * ret = NULL;
997 int size = 0;
998 int ptr = 0;
999 header_line * h = acl_added_headers;
1000 uschar * s;
1001 uschar * cp;
1002
1003 if (!h) return NULL;
1004
1005 do
1006 {
1007 s = h->text;
1008 while ((cp = Ustrchr(s, '\n')) != NULL)
1009 {
1010 if (cp[1] == '\0') break;
1011
1012 /* contains embedded newline; needs doubling */
1013 ret = string_catn(ret, &size, &ptr, s, cp-s+1);
1014 ret = string_catn(ret, &size, &ptr, US"\n", 1);
1015 s = cp+1;
1016 }
1017 /* last bit of header */
1018
1019 ret = string_catn(ret, &size, &ptr, s, cp-s+1); /* newline-sep list */
1020 }
1021 while((h = h->next));
1022
1023 ret[ptr-1] = '\0'; /* overwrite last newline */
1024 return ret;
1025 }
1026
1027
1028 /*************************************************
1029 * Set up removed header line(s) *
1030 *************************************************/
1031
1032 /* This function is called by the remove_header modifier. The argument is
1033 treated as a sequence of header names which are added to a colon separated
1034 list, provided there isn't an identical one already there.
1035
1036 Argument: string of header names
1037 Returns: nothing
1038 */
1039
1040 static void
1041 setup_remove_header(const uschar *hnames)
1042 {
1043 if (*hnames != 0)
1044 acl_removed_headers = acl_removed_headers
1045 ? string_sprintf("%s : %s", acl_removed_headers, hnames)
1046 : string_copy(hnames);
1047 }
1048
1049
1050
1051 /*************************************************
1052 * Handle warnings *
1053 *************************************************/
1054
1055 /* This function is called when a WARN verb's conditions are true. It adds to
1056 the message's headers, and/or writes information to the log. In each case, this
1057 only happens once (per message for headers, per connection for log).
1058
1059 ** NOTE: The header adding action using the "message" setting is historic, and
1060 its use is now deprecated. The new add_header modifier should be used instead.
1061
1062 Arguments:
1063 where ACL_WHERE_xxxx indicating which ACL this is
1064 user_message message for adding to headers
1065 log_message message for logging, if different
1066
1067 Returns: nothing
1068 */
1069
1070 static void
1071 acl_warn(int where, uschar *user_message, uschar *log_message)
1072 {
1073 if (log_message != NULL && log_message != user_message)
1074 {
1075 uschar *text;
1076 string_item *logged;
1077
1078 text = string_sprintf("%s Warning: %s", host_and_ident(TRUE),
1079 string_printing(log_message));
1080
1081 /* If a sender verification has failed, and the log message is "sender verify
1082 failed", add the failure message. */
1083
1084 if (sender_verified_failed != NULL &&
1085 sender_verified_failed->message != NULL &&
1086 strcmpic(log_message, US"sender verify failed") == 0)
1087 text = string_sprintf("%s: %s", text, sender_verified_failed->message);
1088
1089 /* Search previously logged warnings. They are kept in malloc
1090 store so they can be freed at the start of a new message. */
1091
1092 for (logged = acl_warn_logged; logged != NULL; logged = logged->next)
1093 if (Ustrcmp(logged->text, text) == 0) break;
1094
1095 if (logged == NULL)
1096 {
1097 int length = Ustrlen(text) + 1;
1098 log_write(0, LOG_MAIN, "%s", text);
1099 logged = store_malloc(sizeof(string_item) + length);
1100 logged->text = (uschar *)logged + sizeof(string_item);
1101 memcpy(logged->text, text, length);
1102 logged->next = acl_warn_logged;
1103 acl_warn_logged = logged;
1104 }
1105 }
1106
1107 /* If there's no user message, we are done. */
1108
1109 if (user_message == NULL) return;
1110
1111 /* If this isn't a message ACL, we can't do anything with a user message.
1112 Log an error. */
1113
1114 if (where > ACL_WHERE_NOTSMTP)
1115 {
1116 log_write(0, LOG_MAIN|LOG_PANIC, "ACL \"warn\" with \"message\" setting "
1117 "found in a non-message (%s) ACL: cannot specify header lines here: "
1118 "message ignored", acl_wherenames[where]);
1119 return;
1120 }
1121
1122 /* The code for setting up header lines is now abstracted into a separate
1123 function so that it can be used for the add_header modifier as well. */
1124
1125 setup_header(user_message);
1126 }
1127
1128
1129
1130 /*************************************************
1131 * Verify and check reverse DNS *
1132 *************************************************/
1133
1134 /* Called from acl_verify() below. We look up the host name(s) of the client IP
1135 address if this has not yet been done. The host_name_lookup() function checks
1136 that one of these names resolves to an address list that contains the client IP
1137 address, so we don't actually have to do the check here.
1138
1139 Arguments:
1140 user_msgptr pointer for user message
1141 log_msgptr pointer for log message
1142
1143 Returns: OK verification condition succeeded
1144 FAIL verification failed
1145 DEFER there was a problem verifying
1146 */
1147
1148 static int
1149 acl_verify_reverse(uschar **user_msgptr, uschar **log_msgptr)
1150 {
1151 int rc;
1152
1153 user_msgptr = user_msgptr; /* stop compiler warning */
1154
1155 /* Previous success */
1156
1157 if (sender_host_name != NULL) return OK;
1158
1159 /* Previous failure */
1160
1161 if (host_lookup_failed)
1162 {
1163 *log_msgptr = string_sprintf("host lookup failed%s", host_lookup_msg);
1164 return FAIL;
1165 }
1166
1167 /* Need to do a lookup */
1168
1169 HDEBUG(D_acl)
1170 debug_printf_indent("looking up host name to force name/address consistency check\n");
1171
1172 if ((rc = host_name_lookup()) != OK)
1173 {
1174 *log_msgptr = (rc == DEFER)?
1175 US"host lookup deferred for reverse lookup check"
1176 :
1177 string_sprintf("host lookup failed for reverse lookup check%s",
1178 host_lookup_msg);
1179 return rc; /* DEFER or FAIL */
1180 }
1181
1182 host_build_sender_fullhost();
1183 return OK;
1184 }
1185
1186
1187
1188 /*************************************************
1189 * Check client IP address matches CSA target *
1190 *************************************************/
1191
1192 /* Called from acl_verify_csa() below. This routine scans a section of a DNS
1193 response for address records belonging to the CSA target hostname. The section
1194 is specified by the reset argument, either RESET_ADDITIONAL or RESET_ANSWERS.
1195 If one of the addresses matches the client's IP address, then the client is
1196 authorized by CSA. If there are target IP addresses but none of them match
1197 then the client is using an unauthorized IP address. If there are no target IP
1198 addresses then the client cannot be using an authorized IP address. (This is
1199 an odd configuration - why didn't the SRV record have a weight of 1 instead?)
1200
1201 Arguments:
1202 dnsa the DNS answer block
1203 dnss a DNS scan block for us to use
1204 reset option specifying what portion to scan, as described above
1205 target the target hostname to use for matching RR names
1206
1207 Returns: CSA_OK successfully authorized
1208 CSA_FAIL_MISMATCH addresses found but none matched
1209 CSA_FAIL_NOADDR no target addresses found
1210 */
1211
1212 static int
1213 acl_verify_csa_address(dns_answer *dnsa, dns_scan *dnss, int reset,
1214 uschar *target)
1215 {
1216 dns_record *rr;
1217 dns_address *da;
1218
1219 BOOL target_found = FALSE;
1220
1221 for (rr = dns_next_rr(dnsa, dnss, reset);
1222 rr != NULL;
1223 rr = dns_next_rr(dnsa, dnss, RESET_NEXT))
1224 {
1225 /* Check this is an address RR for the target hostname. */
1226
1227 if (rr->type != T_A
1228 #if HAVE_IPV6
1229 && rr->type != T_AAAA
1230 #endif
1231 ) continue;
1232
1233 if (strcmpic(target, rr->name) != 0) continue;
1234
1235 target_found = TRUE;
1236
1237 /* Turn the target address RR into a list of textual IP addresses and scan
1238 the list. There may be more than one if it is an A6 RR. */
1239
1240 for (da = dns_address_from_rr(dnsa, rr); da != NULL; da = da->next)
1241 {
1242 /* If the client IP address matches the target IP address, it's good! */
1243
1244 DEBUG(D_acl) debug_printf_indent("CSA target address is %s\n", da->address);
1245
1246 if (strcmpic(sender_host_address, da->address) == 0) return CSA_OK;
1247 }
1248 }
1249
1250 /* If we found some target addresses but none of them matched, the client is
1251 using an unauthorized IP address, otherwise the target has no authorized IP
1252 addresses. */
1253
1254 if (target_found) return CSA_FAIL_MISMATCH;
1255 else return CSA_FAIL_NOADDR;
1256 }
1257
1258
1259
1260 /*************************************************
1261 * Verify Client SMTP Authorization *
1262 *************************************************/
1263
1264 /* Called from acl_verify() below. This routine calls dns_lookup_special()
1265 to find the CSA SRV record corresponding to the domain argument, or
1266 $sender_helo_name if no argument is provided. It then checks that the
1267 client is authorized, and that its IP address corresponds to the SRV
1268 target's address by calling acl_verify_csa_address() above. The address
1269 should have been returned in the DNS response's ADDITIONAL section, but if
1270 not we perform another DNS lookup to get it.
1271
1272 Arguments:
1273 domain pointer to optional parameter following verify = csa
1274
1275 Returns: CSA_UNKNOWN no valid CSA record found
1276 CSA_OK successfully authorized
1277 CSA_FAIL_* client is definitely not authorized
1278 CSA_DEFER_* there was a DNS problem
1279 */
1280
1281 static int
1282 acl_verify_csa(const uschar *domain)
1283 {
1284 tree_node *t;
1285 const uschar *found;
1286 int priority, weight, port;
1287 dns_answer dnsa;
1288 dns_scan dnss;
1289 dns_record *rr;
1290 int rc, type;
1291 uschar target[256];
1292
1293 /* Work out the domain we are using for the CSA lookup. The default is the
1294 client's HELO domain. If the client has not said HELO, use its IP address
1295 instead. If it's a local client (exim -bs), CSA isn't applicable. */
1296
1297 while (isspace(*domain) && *domain != '\0') ++domain;
1298 if (*domain == '\0') domain = sender_helo_name;
1299 if (domain == NULL) domain = sender_host_address;
1300 if (sender_host_address == NULL) return CSA_UNKNOWN;
1301
1302 /* If we have an address literal, strip off the framing ready for turning it
1303 into a domain. The framing consists of matched square brackets possibly
1304 containing a keyword and a colon before the actual IP address. */
1305
1306 if (domain[0] == '[')
1307 {
1308 const uschar *start = Ustrchr(domain, ':');
1309 if (start == NULL) start = domain;
1310 domain = string_copyn(start + 1, Ustrlen(start) - 2);
1311 }
1312
1313 /* Turn domains that look like bare IP addresses into domains in the reverse
1314 DNS. This code also deals with address literals and $sender_host_address. It's
1315 not quite kosher to treat bare domains such as EHLO 192.0.2.57 the same as
1316 address literals, but it's probably the most friendly thing to do. This is an
1317 extension to CSA, so we allow it to be turned off for proper conformance. */
1318
1319 if (string_is_ip_address(domain, NULL) != 0)
1320 {
1321 if (!dns_csa_use_reverse) return CSA_UNKNOWN;
1322 dns_build_reverse(domain, target);
1323 domain = target;
1324 }
1325
1326 /* Find out if we've already done the CSA check for this domain. If we have,
1327 return the same result again. Otherwise build a new cached result structure
1328 for this domain. The name is filled in now, and the value is filled in when
1329 we return from this function. */
1330
1331 t = tree_search(csa_cache, domain);
1332 if (t != NULL) return t->data.val;
1333
1334 t = store_get_perm(sizeof(tree_node) + Ustrlen(domain));
1335 Ustrcpy(t->name, domain);
1336 (void)tree_insertnode(&csa_cache, t);
1337
1338 /* Now we are ready to do the actual DNS lookup(s). */
1339
1340 found = domain;
1341 switch (dns_special_lookup(&dnsa, domain, T_CSA, &found))
1342 {
1343 /* If something bad happened (most commonly DNS_AGAIN), defer. */
1344
1345 default:
1346 return t->data.val = CSA_DEFER_SRV;
1347
1348 /* If we found nothing, the client's authorization is unknown. */
1349
1350 case DNS_NOMATCH:
1351 case DNS_NODATA:
1352 return t->data.val = CSA_UNKNOWN;
1353
1354 /* We got something! Go on to look at the reply in more detail. */
1355
1356 case DNS_SUCCEED:
1357 break;
1358 }
1359
1360 /* Scan the reply for well-formed CSA SRV records. */
1361
1362 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
1363 rr;
1364 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) if (rr->type == T_SRV)
1365 {
1366 const uschar * p = rr->data;
1367
1368 /* Extract the numerical SRV fields (p is incremented) */
1369
1370 GETSHORT(priority, p);
1371 GETSHORT(weight, p);
1372 GETSHORT(port, p);
1373
1374 DEBUG(D_acl)
1375 debug_printf_indent("CSA priority=%d weight=%d port=%d\n", priority, weight, port);
1376
1377 /* Check the CSA version number */
1378
1379 if (priority != 1) continue;
1380
1381 /* If the domain does not have a CSA SRV record of its own (i.e. the domain
1382 found by dns_special_lookup() is a parent of the one we asked for), we check
1383 the subdomain assertions in the port field. At the moment there's only one
1384 assertion: legitimate SMTP clients are all explicitly authorized with CSA
1385 SRV records of their own. */
1386
1387 if (Ustrcmp(found, domain) != 0)
1388 return t->data.val = port & 1 ? CSA_FAIL_EXPLICIT : CSA_UNKNOWN;
1389
1390 /* This CSA SRV record refers directly to our domain, so we check the value
1391 in the weight field to work out the domain's authorization. 0 and 1 are
1392 unauthorized; 3 means the client is authorized but we can't check the IP
1393 address in order to authenticate it, so we treat it as unknown; values
1394 greater than 3 are undefined. */
1395
1396 if (weight < 2) return t->data.val = CSA_FAIL_DOMAIN;
1397
1398 if (weight > 2) continue;
1399
1400 /* Weight == 2, which means the domain is authorized. We must check that the
1401 client's IP address is listed as one of the SRV target addresses. Save the
1402 target hostname then break to scan the additional data for its addresses. */
1403
1404 (void)dn_expand(dnsa.answer, dnsa.answer + dnsa.answerlen, p,
1405 (DN_EXPAND_ARG4_TYPE)target, sizeof(target));
1406
1407 DEBUG(D_acl) debug_printf_indent("CSA target is %s\n", target);
1408
1409 break;
1410 }
1411
1412 /* If we didn't break the loop then no appropriate records were found. */
1413
1414 if (rr == NULL) return t->data.val = CSA_UNKNOWN;
1415
1416 /* Do not check addresses if the target is ".", in accordance with RFC 2782.
1417 A target of "." indicates there are no valid addresses, so the client cannot
1418 be authorized. (This is an odd configuration because weight=2 target=. is
1419 equivalent to weight=1, but we check for it in order to keep load off the
1420 root name servers.) Note that dn_expand() turns "." into "". */
1421
1422 if (Ustrcmp(target, "") == 0) return t->data.val = CSA_FAIL_NOADDR;
1423
1424 /* Scan the additional section of the CSA SRV reply for addresses belonging
1425 to the target. If the name server didn't return any additional data (e.g.
1426 because it does not fully support SRV records), we need to do another lookup
1427 to obtain the target addresses; otherwise we have a definitive result. */
1428
1429 rc = acl_verify_csa_address(&dnsa, &dnss, RESET_ADDITIONAL, target);
1430 if (rc != CSA_FAIL_NOADDR) return t->data.val = rc;
1431
1432 /* The DNS lookup type corresponds to the IP version used by the client. */
1433
1434 #if HAVE_IPV6
1435 if (Ustrchr(sender_host_address, ':') != NULL)
1436 type = T_AAAA;
1437 else
1438 #endif /* HAVE_IPV6 */
1439 type = T_A;
1440
1441
1442 lookup_dnssec_authenticated = NULL;
1443 switch (dns_lookup(&dnsa, target, type, NULL))
1444 {
1445 /* If something bad happened (most commonly DNS_AGAIN), defer. */
1446
1447 default:
1448 return t->data.val = CSA_DEFER_ADDR;
1449
1450 /* If the query succeeded, scan the addresses and return the result. */
1451
1452 case DNS_SUCCEED:
1453 rc = acl_verify_csa_address(&dnsa, &dnss, RESET_ANSWERS, target);
1454 if (rc != CSA_FAIL_NOADDR) return t->data.val = rc;
1455 /* else fall through */
1456
1457 /* If the target has no IP addresses, the client cannot have an authorized
1458 IP address. However, if the target site uses A6 records (not AAAA records)
1459 we have to do yet another lookup in order to check them. */
1460
1461 case DNS_NOMATCH:
1462 case DNS_NODATA:
1463 return t->data.val = CSA_FAIL_NOADDR;
1464 }
1465 }
1466
1467
1468
1469 /*************************************************
1470 * Handle verification (address & other) *
1471 *************************************************/
1472
1473 enum { VERIFY_REV_HOST_LKUP, VERIFY_CERT, VERIFY_HELO, VERIFY_CSA, VERIFY_HDR_SYNTAX,
1474 VERIFY_NOT_BLIND, VERIFY_HDR_SNDR, VERIFY_SNDR, VERIFY_RCPT,
1475 VERIFY_HDR_NAMES_ASCII
1476 };
1477 typedef struct {
1478 uschar * name;
1479 int value;
1480 unsigned where_allowed; /* bitmap */
1481 BOOL no_options; /* Never has /option(s) following */
1482 unsigned alt_opt_sep; /* >0 Non-/ option separator (custom parser) */
1483 } verify_type_t;
1484 static verify_type_t verify_type_list[] = {
1485 { US"reverse_host_lookup", VERIFY_REV_HOST_LKUP, ~0, FALSE, 0 },
1486 { US"certificate", VERIFY_CERT, ~0, TRUE, 0 },
1487 { US"helo", VERIFY_HELO, ~0, TRUE, 0 },
1488 { US"csa", VERIFY_CSA, ~0, FALSE, 0 },
1489 { US"header_syntax", VERIFY_HDR_SYNTAX, (1<<ACL_WHERE_DATA)|(1<<ACL_WHERE_NOTSMTP), TRUE, 0 },
1490 { US"not_blind", VERIFY_NOT_BLIND, (1<<ACL_WHERE_DATA)|(1<<ACL_WHERE_NOTSMTP), TRUE, 0 },
1491 { US"header_sender", VERIFY_HDR_SNDR, (1<<ACL_WHERE_DATA)|(1<<ACL_WHERE_NOTSMTP), FALSE, 0 },
1492 { US"sender", VERIFY_SNDR, (1<<ACL_WHERE_MAIL)|(1<<ACL_WHERE_RCPT)
1493 |(1<<ACL_WHERE_PREDATA)|(1<<ACL_WHERE_DATA)|(1<<ACL_WHERE_NOTSMTP),
1494 FALSE, 6 },
1495 { US"recipient", VERIFY_RCPT, (1<<ACL_WHERE_RCPT), FALSE, 0 },
1496 { US"header_names_ascii", VERIFY_HDR_NAMES_ASCII, (1<<ACL_WHERE_DATA)|(1<<ACL_WHERE_NOTSMTP), TRUE, 0 }
1497 };
1498
1499
1500 enum { CALLOUT_DEFER_OK, CALLOUT_NOCACHE, CALLOUT_RANDOM, CALLOUT_USE_SENDER,
1501 CALLOUT_USE_POSTMASTER, CALLOUT_POSTMASTER, CALLOUT_FULLPOSTMASTER,
1502 CALLOUT_MAILFROM, CALLOUT_POSTMASTER_MAILFROM, CALLOUT_MAXWAIT, CALLOUT_CONNECT,
1503 CALLOUT_HOLD, CALLOUT_TIME /* TIME must be last */
1504 };
1505 typedef struct {
1506 uschar * name;
1507 int value;
1508 int flag;
1509 BOOL has_option; /* Has =option(s) following */
1510 BOOL timeval; /* Has a time value */
1511 } callout_opt_t;
1512 static callout_opt_t callout_opt_list[] = {
1513 { US"defer_ok", CALLOUT_DEFER_OK, 0, FALSE, FALSE },
1514 { US"no_cache", CALLOUT_NOCACHE, vopt_callout_no_cache, FALSE, FALSE },
1515 { US"random", CALLOUT_RANDOM, vopt_callout_random, FALSE, FALSE },
1516 { US"use_sender", CALLOUT_USE_SENDER, vopt_callout_recipsender, FALSE, FALSE },
1517 { US"use_postmaster", CALLOUT_USE_POSTMASTER,vopt_callout_recippmaster, FALSE, FALSE },
1518 { US"postmaster_mailfrom",CALLOUT_POSTMASTER_MAILFROM,0, TRUE, FALSE },
1519 { US"postmaster", CALLOUT_POSTMASTER, 0, FALSE, FALSE },
1520 { US"fullpostmaster", CALLOUT_FULLPOSTMASTER,vopt_callout_fullpm, FALSE, FALSE },
1521 { US"mailfrom", CALLOUT_MAILFROM, 0, TRUE, FALSE },
1522 { US"maxwait", CALLOUT_MAXWAIT, 0, TRUE, TRUE },
1523 { US"connect", CALLOUT_CONNECT, 0, TRUE, TRUE },
1524 { US"hold", CALLOUT_HOLD, vopt_callout_hold, FALSE, FALSE },
1525 { NULL, CALLOUT_TIME, 0, FALSE, TRUE }
1526 };
1527
1528
1529
1530 /* This function implements the "verify" condition. It is called when
1531 encountered in any ACL, because some tests are almost always permitted. Some
1532 just don't make sense, and always fail (for example, an attempt to test a host
1533 lookup for a non-TCP/IP message). Others are restricted to certain ACLs.
1534
1535 Arguments:
1536 where where called from
1537 addr the recipient address that the ACL is handling, or NULL
1538 arg the argument of "verify"
1539 user_msgptr pointer for user message
1540 log_msgptr pointer for log message
1541 basic_errno where to put verify errno
1542
1543 Returns: OK verification condition succeeded
1544 FAIL verification failed
1545 DEFER there was a problem verifying
1546 ERROR syntax error
1547 */
1548
1549 static int
1550 acl_verify(int where, address_item *addr, const uschar *arg,
1551 uschar **user_msgptr, uschar **log_msgptr, int *basic_errno)
1552 {
1553 int sep = '/';
1554 int callout = -1;
1555 int callout_overall = -1;
1556 int callout_connect = -1;
1557 int verify_options = 0;
1558 int rc;
1559 BOOL verify_header_sender = FALSE;
1560 BOOL defer_ok = FALSE;
1561 BOOL callout_defer_ok = FALSE;
1562 BOOL no_details = FALSE;
1563 BOOL success_on_redirect = FALSE;
1564 address_item *sender_vaddr = NULL;
1565 uschar *verify_sender_address = NULL;
1566 uschar *pm_mailfrom = NULL;
1567 uschar *se_mailfrom = NULL;
1568
1569 /* Some of the verify items have slash-separated options; some do not. Diagnose
1570 an error if options are given for items that don't expect them.
1571 */
1572
1573 uschar *slash = Ustrchr(arg, '/');
1574 const uschar *list = arg;
1575 uschar *ss = string_nextinlist(&list, &sep, big_buffer, big_buffer_size);
1576 verify_type_t * vp;
1577
1578 if (ss == NULL) goto BAD_VERIFY;
1579
1580 /* Handle name/address consistency verification in a separate function. */
1581
1582 for (vp= verify_type_list;
1583 (char *)vp < (char *)verify_type_list + sizeof(verify_type_list);
1584 vp++
1585 )
1586 if (vp->alt_opt_sep ? strncmpic(ss, vp->name, vp->alt_opt_sep) == 0
1587 : strcmpic (ss, vp->name) == 0)
1588 break;
1589 if ((char *)vp >= (char *)verify_type_list + sizeof(verify_type_list))
1590 goto BAD_VERIFY;
1591
1592 if (vp->no_options && slash != NULL)
1593 {
1594 *log_msgptr = string_sprintf("unexpected '/' found in \"%s\" "
1595 "(this verify item has no options)", arg);
1596 return ERROR;
1597 }
1598 if (!(vp->where_allowed & (1<<where)))
1599 {
1600 *log_msgptr = string_sprintf("cannot verify %s in ACL for %s", vp->name, acl_wherenames[where]);
1601 return ERROR;
1602 }
1603 switch(vp->value)
1604 {
1605 case VERIFY_REV_HOST_LKUP:
1606 if (sender_host_address == NULL) return OK;
1607 if ((rc = acl_verify_reverse(user_msgptr, log_msgptr)) == DEFER)
1608 while ((ss = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1609 if (strcmpic(ss, US"defer_ok") == 0)
1610 return OK;
1611 return rc;
1612
1613 case VERIFY_CERT:
1614 /* TLS certificate verification is done at STARTTLS time; here we just
1615 test whether it was successful or not. (This is for optional verification; for
1616 mandatory verification, the connection doesn't last this long.) */
1617
1618 if (tls_in.certificate_verified) return OK;
1619 *user_msgptr = US"no verified certificate";
1620 return FAIL;
1621
1622 case VERIFY_HELO:
1623 /* We can test the result of optional HELO verification that might have
1624 occurred earlier. If not, we can attempt the verification now. */
1625
1626 if (!helo_verified && !helo_verify_failed) smtp_verify_helo();
1627 return helo_verified? OK : FAIL;
1628
1629 case VERIFY_CSA:
1630 /* Do Client SMTP Authorization checks in a separate function, and turn the
1631 result code into user-friendly strings. */
1632
1633 rc = acl_verify_csa(list);
1634 *log_msgptr = *user_msgptr = string_sprintf("client SMTP authorization %s",
1635 csa_reason_string[rc]);
1636 csa_status = csa_status_string[rc];
1637 DEBUG(D_acl) debug_printf_indent("CSA result %s\n", csa_status);
1638 return csa_return_code[rc];
1639
1640 case VERIFY_HDR_SYNTAX:
1641 /* Check that all relevant header lines have the correct syntax. If there is
1642 a syntax error, we return details of the error to the sender if configured to
1643 send out full details. (But a "message" setting on the ACL can override, as
1644 always). */
1645
1646 rc = verify_check_headers(log_msgptr);
1647 if (rc != OK && *log_msgptr)
1648 if (smtp_return_error_details)
1649 *user_msgptr = string_sprintf("Rejected after DATA: %s", *log_msgptr);
1650 else
1651 acl_verify_message = *log_msgptr;
1652 return rc;
1653
1654 case VERIFY_HDR_NAMES_ASCII:
1655 /* Check that all header names are true 7 bit strings
1656 See RFC 5322, 2.2. and RFC 6532, 3. */
1657
1658 rc = verify_check_header_names_ascii(log_msgptr);
1659 if (rc != OK && smtp_return_error_details && *log_msgptr != NULL)
1660 *user_msgptr = string_sprintf("Rejected after DATA: %s", *log_msgptr);
1661 return rc;
1662
1663 case VERIFY_NOT_BLIND:
1664 /* Check that no recipient of this message is "blind", that is, every envelope
1665 recipient must be mentioned in either To: or Cc:. */
1666
1667 rc = verify_check_notblind();
1668 if (rc != OK)
1669 {
1670 *log_msgptr = string_sprintf("bcc recipient detected");
1671 if (smtp_return_error_details)
1672 *user_msgptr = string_sprintf("Rejected after DATA: %s", *log_msgptr);
1673 }
1674 return rc;
1675
1676 /* The remaining verification tests check recipient and sender addresses,
1677 either from the envelope or from the header. There are a number of
1678 slash-separated options that are common to all of them. */
1679
1680 case VERIFY_HDR_SNDR:
1681 verify_header_sender = TRUE;
1682 break;
1683
1684 case VERIFY_SNDR:
1685 /* In the case of a sender, this can optionally be followed by an address to use
1686 in place of the actual sender (rare special-case requirement). */
1687 {
1688 uschar *s = ss + 6;
1689 if (*s == 0)
1690 verify_sender_address = sender_address;
1691 else
1692 {
1693 while (isspace(*s)) s++;
1694 if (*s++ != '=') goto BAD_VERIFY;
1695 while (isspace(*s)) s++;
1696 verify_sender_address = string_copy(s);
1697 }
1698 }
1699 break;
1700
1701 case VERIFY_RCPT:
1702 break;
1703 }
1704
1705
1706
1707 /* Remaining items are optional; they apply to sender and recipient
1708 verification, including "header sender" verification. */
1709
1710 while ((ss = string_nextinlist(&list, &sep, big_buffer, big_buffer_size))
1711 != NULL)
1712 {
1713 if (strcmpic(ss, US"defer_ok") == 0) defer_ok = TRUE;
1714 else if (strcmpic(ss, US"no_details") == 0) no_details = TRUE;
1715 else if (strcmpic(ss, US"success_on_redirect") == 0) success_on_redirect = TRUE;
1716
1717 /* These two old options are left for backwards compatibility */
1718
1719 else if (strcmpic(ss, US"callout_defer_ok") == 0)
1720 {
1721 callout_defer_ok = TRUE;
1722 if (callout == -1) callout = CALLOUT_TIMEOUT_DEFAULT;
1723 }
1724
1725 else if (strcmpic(ss, US"check_postmaster") == 0)
1726 {
1727 pm_mailfrom = US"";
1728 if (callout == -1) callout = CALLOUT_TIMEOUT_DEFAULT;
1729 }
1730
1731 /* The callout option has a number of sub-options, comma separated */
1732
1733 else if (strncmpic(ss, US"callout", 7) == 0)
1734 {
1735 callout = CALLOUT_TIMEOUT_DEFAULT;
1736 ss += 7;
1737 if (*ss != 0)
1738 {
1739 while (isspace(*ss)) ss++;
1740 if (*ss++ == '=')
1741 {
1742 const uschar * sublist = ss;
1743 int optsep = ',';
1744 uschar *opt;
1745 uschar buffer[256];
1746 while (isspace(*sublist)) sublist++;
1747
1748 while ((opt = string_nextinlist(&sublist, &optsep, buffer, sizeof(buffer))))
1749 {
1750 callout_opt_t * op;
1751 double period = 1.0F;
1752
1753 for (op= callout_opt_list; op->name; op++)
1754 if (strncmpic(opt, op->name, Ustrlen(op->name)) == 0)
1755 break;
1756
1757 verify_options |= op->flag;
1758 if (op->has_option)
1759 {
1760 opt += Ustrlen(op->name);
1761 while (isspace(*opt)) opt++;
1762 if (*opt++ != '=')
1763 {
1764 *log_msgptr = string_sprintf("'=' expected after "
1765 "\"%s\" in ACL verify condition \"%s\"", op->name, arg);
1766 return ERROR;
1767 }
1768 while (isspace(*opt)) opt++;
1769 }
1770 if (op->timeval && (period = readconf_readtime(opt, 0, FALSE)) < 0)
1771 {
1772 *log_msgptr = string_sprintf("bad time value in ACL condition "
1773 "\"verify %s\"", arg);
1774 return ERROR;
1775 }
1776
1777 switch(op->value)
1778 {
1779 case CALLOUT_DEFER_OK: callout_defer_ok = TRUE; break;
1780 case CALLOUT_POSTMASTER: pm_mailfrom = US""; break;
1781 case CALLOUT_FULLPOSTMASTER: pm_mailfrom = US""; break;
1782 case CALLOUT_MAILFROM:
1783 if (!verify_header_sender)
1784 {
1785 *log_msgptr = string_sprintf("\"mailfrom\" is allowed as a "
1786 "callout option only for verify=header_sender (detected in ACL "
1787 "condition \"%s\")", arg);
1788 return ERROR;
1789 }
1790 se_mailfrom = string_copy(opt);
1791 break;
1792 case CALLOUT_POSTMASTER_MAILFROM: pm_mailfrom = string_copy(opt); break;
1793 case CALLOUT_MAXWAIT: callout_overall = period; break;
1794 case CALLOUT_CONNECT: callout_connect = period; break;
1795 case CALLOUT_TIME: callout = period; break;
1796 }
1797 }
1798 }
1799 else
1800 {
1801 *log_msgptr = string_sprintf("'=' expected after \"callout\" in "
1802 "ACL condition \"%s\"", arg);
1803 return ERROR;
1804 }
1805 }
1806 }
1807
1808 /* Option not recognized */
1809
1810 else
1811 {
1812 *log_msgptr = string_sprintf("unknown option \"%s\" in ACL "
1813 "condition \"verify %s\"", ss, arg);
1814 return ERROR;
1815 }
1816 }
1817
1818 if ((verify_options & (vopt_callout_recipsender|vopt_callout_recippmaster)) ==
1819 (vopt_callout_recipsender|vopt_callout_recippmaster))
1820 {
1821 *log_msgptr = US"only one of use_sender and use_postmaster can be set "
1822 "for a recipient callout";
1823 return ERROR;
1824 }
1825
1826 /* Handle sender-in-header verification. Default the user message to the log
1827 message if giving out verification details. */
1828
1829 if (verify_header_sender)
1830 {
1831 int verrno;
1832
1833 if ((rc = verify_check_header_address(user_msgptr, log_msgptr, callout,
1834 callout_overall, callout_connect, se_mailfrom, pm_mailfrom, verify_options,
1835 &verrno)) != OK)
1836 {
1837 *basic_errno = verrno;
1838 if (smtp_return_error_details)
1839 {
1840 if (!*user_msgptr && *log_msgptr)
1841 *user_msgptr = string_sprintf("Rejected after DATA: %s", *log_msgptr);
1842 if (rc == DEFER) acl_temp_details = TRUE;
1843 }
1844 }
1845 }
1846
1847 /* Handle a sender address. The default is to verify *the* sender address, but
1848 optionally a different address can be given, for special requirements. If the
1849 address is empty, we are dealing with a bounce message that has no sender, so
1850 we cannot do any checking. If the real sender address gets rewritten during
1851 verification (e.g. DNS widening), set the flag to stop it being rewritten again
1852 during message reception.
1853
1854 A list of verified "sender" addresses is kept to try to avoid doing to much
1855 work repetitively when there are multiple recipients in a message and they all
1856 require sender verification. However, when callouts are involved, it gets too
1857 complicated because different recipients may require different callout options.
1858 Therefore, we always do a full sender verify when any kind of callout is
1859 specified. Caching elsewhere, for instance in the DNS resolver and in the
1860 callout handling, should ensure that this is not terribly inefficient. */
1861
1862 else if (verify_sender_address)
1863 {
1864 if ((verify_options & (vopt_callout_recipsender|vopt_callout_recippmaster)))
1865 {
1866 *log_msgptr = US"use_sender or use_postmaster cannot be used for a "
1867 "sender verify callout";
1868 return ERROR;
1869 }
1870
1871 sender_vaddr = verify_checked_sender(verify_sender_address);
1872 if (sender_vaddr != NULL && /* Previously checked */
1873 callout <= 0) /* No callout needed this time */
1874 {
1875 /* If the "routed" flag is set, it means that routing worked before, so
1876 this check can give OK (the saved return code value, if set, belongs to a
1877 callout that was done previously). If the "routed" flag is not set, routing
1878 must have failed, so we use the saved return code. */
1879
1880 if (testflag(sender_vaddr, af_verify_routed))
1881 rc = OK;
1882 else
1883 {
1884 rc = sender_vaddr->special_action;
1885 *basic_errno = sender_vaddr->basic_errno;
1886 }
1887 HDEBUG(D_acl) debug_printf_indent("using cached sender verify result\n");
1888 }
1889
1890 /* Do a new verification, and cache the result. The cache is used to avoid
1891 verifying the sender multiple times for multiple RCPTs when callouts are not
1892 specified (see comments above).
1893
1894 The cache is also used on failure to give details in response to the first
1895 RCPT that gets bounced for this reason. However, this can be suppressed by
1896 the no_details option, which sets the flag that says "this detail has already
1897 been sent". The cache normally contains just one address, but there may be
1898 more in esoteric circumstances. */
1899
1900 else
1901 {
1902 BOOL routed = TRUE;
1903 uschar *save_address_data = deliver_address_data;
1904
1905 sender_vaddr = deliver_make_addr(verify_sender_address, TRUE);
1906 #ifdef SUPPORT_I18N
1907 if ((sender_vaddr->prop.utf8_msg = message_smtputf8))
1908 {
1909 sender_vaddr->prop.utf8_downcvt = message_utf8_downconvert == 1;
1910 sender_vaddr->prop.utf8_downcvt_maybe = message_utf8_downconvert == -1;
1911 }
1912 #endif
1913 if (no_details) setflag(sender_vaddr, af_sverify_told);
1914 if (verify_sender_address[0] != 0)
1915 {
1916 /* If this is the real sender address, save the unrewritten version
1917 for use later in receive. Otherwise, set a flag so that rewriting the
1918 sender in verify_address() does not update sender_address. */
1919
1920 if (verify_sender_address == sender_address)
1921 sender_address_unrewritten = sender_address;
1922 else
1923 verify_options |= vopt_fake_sender;
1924
1925 if (success_on_redirect)
1926 verify_options |= vopt_success_on_redirect;
1927
1928 /* The recipient, qualify, and expn options are never set in
1929 verify_options. */
1930
1931 rc = verify_address(sender_vaddr, NULL, verify_options, callout,
1932 callout_overall, callout_connect, se_mailfrom, pm_mailfrom, &routed);
1933
1934 HDEBUG(D_acl) debug_printf_indent("----------- end verify ------------\n");
1935
1936 if (rc != OK)
1937 *basic_errno = sender_vaddr->basic_errno;
1938 else
1939 DEBUG(D_acl)
1940 {
1941 if (Ustrcmp(sender_vaddr->address, verify_sender_address) != 0)
1942 debug_printf_indent("sender %s verified ok as %s\n",
1943 verify_sender_address, sender_vaddr->address);
1944 else
1945 debug_printf_indent("sender %s verified ok\n",
1946 verify_sender_address);
1947 }
1948 }
1949 else
1950 rc = OK; /* Null sender */
1951
1952 /* Cache the result code */
1953
1954 if (routed) setflag(sender_vaddr, af_verify_routed);
1955 if (callout > 0) setflag(sender_vaddr, af_verify_callout);
1956 sender_vaddr->special_action = rc;
1957 sender_vaddr->next = sender_verified_list;
1958 sender_verified_list = sender_vaddr;
1959
1960 /* Restore the recipient address data, which might have been clobbered by
1961 the sender verification. */
1962
1963 deliver_address_data = save_address_data;
1964 }
1965
1966 /* Put the sender address_data value into $sender_address_data */
1967
1968 sender_address_data = sender_vaddr->prop.address_data;
1969 }
1970
1971 /* A recipient address just gets a straightforward verify; again we must handle
1972 the DEFER overrides. */
1973
1974 else
1975 {
1976 address_item addr2;
1977
1978 if (success_on_redirect)
1979 verify_options |= vopt_success_on_redirect;
1980
1981 /* We must use a copy of the address for verification, because it might
1982 get rewritten. */
1983
1984 addr2 = *addr;
1985 rc = verify_address(&addr2, NULL, verify_options|vopt_is_recipient, callout,
1986 callout_overall, callout_connect, se_mailfrom, pm_mailfrom, NULL);
1987 HDEBUG(D_acl) debug_printf_indent("----------- end verify ------------\n");
1988
1989 *basic_errno = addr2.basic_errno;
1990 *log_msgptr = addr2.message;
1991 *user_msgptr = (addr2.user_message != NULL)?
1992 addr2.user_message : addr2.message;
1993
1994 /* Allow details for temporary error if the address is so flagged. */
1995 if (testflag((&addr2), af_pass_message)) acl_temp_details = TRUE;
1996
1997 /* Make $address_data visible */
1998 deliver_address_data = addr2.prop.address_data;
1999 }
2000
2001 /* We have a result from the relevant test. Handle defer overrides first. */
2002
2003 if (rc == DEFER && (defer_ok ||
2004 (callout_defer_ok && *basic_errno == ERRNO_CALLOUTDEFER)))
2005 {
2006 HDEBUG(D_acl) debug_printf_indent("verify defer overridden by %s\n",
2007 defer_ok? "defer_ok" : "callout_defer_ok");
2008 rc = OK;
2009 }
2010
2011 /* If we've failed a sender, set up a recipient message, and point
2012 sender_verified_failed to the address item that actually failed. */
2013
2014 if (rc != OK && verify_sender_address != NULL)
2015 {
2016 if (rc != DEFER)
2017 *log_msgptr = *user_msgptr = US"Sender verify failed";
2018 else if (*basic_errno != ERRNO_CALLOUTDEFER)
2019 *log_msgptr = *user_msgptr = US"Could not complete sender verify";
2020 else
2021 {
2022 *log_msgptr = US"Could not complete sender verify callout";
2023 *user_msgptr = smtp_return_error_details? sender_vaddr->user_message :
2024 *log_msgptr;
2025 }
2026
2027 sender_verified_failed = sender_vaddr;
2028 }
2029
2030 /* Verifying an address messes up the values of $domain and $local_part,
2031 so reset them before returning if this is a RCPT ACL. */
2032
2033 if (addr != NULL)
2034 {
2035 deliver_domain = addr->domain;
2036 deliver_localpart = addr->local_part;
2037 }
2038 return rc;
2039
2040 /* Syntax errors in the verify argument come here. */
2041
2042 BAD_VERIFY:
2043 *log_msgptr = string_sprintf("expected \"sender[=address]\", \"recipient\", "
2044 "\"helo\", \"header_syntax\", \"header_sender\", \"header_names_ascii\" "
2045 "or \"reverse_host_lookup\" at start of ACL condition "
2046 "\"verify %s\"", arg);
2047 return ERROR;
2048 }
2049
2050
2051
2052
2053 /*************************************************
2054 * Check argument for control= modifier *
2055 *************************************************/
2056
2057 /* Called from acl_check_condition() below
2058
2059 Arguments:
2060 arg the argument string for control=
2061 pptr set to point to the terminating character
2062 where which ACL we are in
2063 log_msgptr for error messages
2064
2065 Returns: CONTROL_xxx value
2066 */
2067
2068 static int
2069 decode_control(const uschar *arg, const uschar **pptr, int where, uschar **log_msgptr)
2070 {
2071 int idx, len;
2072 control_def * d;
2073
2074 if ( (idx = find_control(arg, controls_list, nelem(controls_list))) < 0
2075 || ( arg[len = Ustrlen((d = controls_list+idx)->name)] != 0
2076 && (!d->has_option || arg[len] != '/')
2077 ) )
2078 {
2079 *log_msgptr = string_sprintf("syntax error in \"control=%s\"", arg);
2080 return CONTROL_ERROR;
2081 }
2082
2083 *pptr = arg + len;
2084 return idx;
2085 }
2086
2087
2088
2089
2090 /*************************************************
2091 * Return a ratelimit error *
2092 *************************************************/
2093
2094 /* Called from acl_ratelimit() below
2095
2096 Arguments:
2097 log_msgptr for error messages
2098 format format string
2099 ... supplementary arguments
2100 ss ratelimit option name
2101 where ACL_WHERE_xxxx indicating which ACL this is
2102
2103 Returns: ERROR
2104 */
2105
2106 static int
2107 ratelimit_error(uschar **log_msgptr, const char *format, ...)
2108 {
2109 va_list ap;
2110 uschar buffer[STRING_SPRINTF_BUFFER_SIZE];
2111 va_start(ap, format);
2112 if (!string_vformat(buffer, sizeof(buffer), format, ap))
2113 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2114 "string_sprintf expansion was longer than " SIZE_T_FMT, sizeof(buffer));
2115 va_end(ap);
2116 *log_msgptr = string_sprintf(
2117 "error in arguments to \"ratelimit\" condition: %s", buffer);
2118 return ERROR;
2119 }
2120
2121
2122
2123
2124 /*************************************************
2125 * Handle rate limiting *
2126 *************************************************/
2127
2128 /* Called by acl_check_condition() below to calculate the result
2129 of the ACL ratelimit condition.
2130
2131 Note that the return value might be slightly unexpected: if the
2132 sender's rate is above the limit then the result is OK. This is
2133 similar to the dnslists condition, and is so that you can write
2134 ACL clauses like: defer ratelimit = 15 / 1h
2135
2136 Arguments:
2137 arg the option string for ratelimit=
2138 where ACL_WHERE_xxxx indicating which ACL this is
2139 log_msgptr for error messages
2140
2141 Returns: OK - Sender's rate is above limit
2142 FAIL - Sender's rate is below limit
2143 DEFER - Problem opening ratelimit database
2144 ERROR - Syntax error in options.
2145 */
2146
2147 static int
2148 acl_ratelimit(const uschar *arg, int where, uschar **log_msgptr)
2149 {
2150 double limit, period, count;
2151 uschar *ss;
2152 uschar *key = NULL;
2153 uschar *unique = NULL;
2154 int sep = '/';
2155 BOOL leaky = FALSE, strict = FALSE, readonly = FALSE;
2156 BOOL noupdate = FALSE, badacl = FALSE;
2157 int mode = RATE_PER_WHAT;
2158 int old_pool, rc;
2159 tree_node **anchor, *t;
2160 open_db dbblock, *dbm;
2161 int dbdb_size;
2162 dbdata_ratelimit *dbd;
2163 dbdata_ratelimit_unique *dbdb;
2164 struct timeval tv;
2165
2166 /* Parse the first two options and record their values in expansion
2167 variables. These variables allow the configuration to have informative
2168 error messages based on rate limits obtained from a table lookup. */
2169
2170 /* First is the maximum number of messages per period / maximum burst
2171 size, which must be greater than or equal to zero. Zero is useful for
2172 rate measurement as opposed to rate limiting. */
2173
2174 sender_rate_limit = string_nextinlist(&arg, &sep, NULL, 0);
2175 if (sender_rate_limit == NULL)
2176 return ratelimit_error(log_msgptr, "sender rate limit not set");
2177
2178 limit = Ustrtod(sender_rate_limit, &ss);
2179 if (tolower(*ss) == 'k') { limit *= 1024.0; ss++; }
2180 else if (tolower(*ss) == 'm') { limit *= 1024.0*1024.0; ss++; }
2181 else if (tolower(*ss) == 'g') { limit *= 1024.0*1024.0*1024.0; ss++; }
2182
2183 if (limit < 0.0 || *ss != '\0')
2184 return ratelimit_error(log_msgptr,
2185 "\"%s\" is not a positive number", sender_rate_limit);
2186
2187 /* Second is the rate measurement period / exponential smoothing time
2188 constant. This must be strictly greater than zero, because zero leads to
2189 run-time division errors. */
2190
2191 sender_rate_period = string_nextinlist(&arg, &sep, NULL, 0);
2192 if (sender_rate_period == NULL) period = -1.0;
2193 else period = readconf_readtime(sender_rate_period, 0, FALSE);
2194 if (period <= 0.0)
2195 return ratelimit_error(log_msgptr,
2196 "\"%s\" is not a time value", sender_rate_period);
2197
2198 /* By default we are counting one of something, but the per_rcpt,
2199 per_byte, and count options can change this. */
2200
2201 count = 1.0;
2202
2203 /* Parse the other options. */
2204
2205 while ((ss = string_nextinlist(&arg, &sep, big_buffer, big_buffer_size))
2206 != NULL)
2207 {
2208 if (strcmpic(ss, US"leaky") == 0) leaky = TRUE;
2209 else if (strcmpic(ss, US"strict") == 0) strict = TRUE;
2210 else if (strcmpic(ss, US"noupdate") == 0) noupdate = TRUE;
2211 else if (strcmpic(ss, US"readonly") == 0) readonly = TRUE;
2212 else if (strcmpic(ss, US"per_cmd") == 0) RATE_SET(mode, PER_CMD);
2213 else if (strcmpic(ss, US"per_conn") == 0)
2214 {
2215 RATE_SET(mode, PER_CONN);
2216 if (where == ACL_WHERE_NOTSMTP || where == ACL_WHERE_NOTSMTP_START)
2217 badacl = TRUE;
2218 }
2219 else if (strcmpic(ss, US"per_mail") == 0)
2220 {
2221 RATE_SET(mode, PER_MAIL);
2222 if (where > ACL_WHERE_NOTSMTP) badacl = TRUE;
2223 }
2224 else if (strcmpic(ss, US"per_rcpt") == 0)
2225 {
2226 /* If we are running in the RCPT ACL, then we'll count the recipients
2227 one by one, but if we are running when we have accumulated the whole
2228 list then we'll add them all in one batch. */
2229 if (where == ACL_WHERE_RCPT)
2230 RATE_SET(mode, PER_RCPT);
2231 else if (where >= ACL_WHERE_PREDATA && where <= ACL_WHERE_NOTSMTP)
2232 RATE_SET(mode, PER_ALLRCPTS), count = (double)recipients_count;
2233 else if (where == ACL_WHERE_MAIL || where > ACL_WHERE_NOTSMTP)
2234 RATE_SET(mode, PER_RCPT), badacl = TRUE;
2235 }
2236 else if (strcmpic(ss, US"per_byte") == 0)
2237 {
2238 /* If we have not yet received the message data and there was no SIZE
2239 declaration on the MAIL command, then it's safe to just use a value of
2240 zero and let the recorded rate decay as if nothing happened. */
2241 RATE_SET(mode, PER_MAIL);
2242 if (where > ACL_WHERE_NOTSMTP) badacl = TRUE;
2243 else count = message_size < 0 ? 0.0 : (double)message_size;
2244 }
2245 else if (strcmpic(ss, US"per_addr") == 0)
2246 {
2247 RATE_SET(mode, PER_RCPT);
2248 if (where != ACL_WHERE_RCPT) badacl = TRUE, unique = US"*";
2249 else unique = string_sprintf("%s@%s", deliver_localpart, deliver_domain);
2250 }
2251 else if (strncmpic(ss, US"count=", 6) == 0)
2252 {
2253 uschar *e;
2254 count = Ustrtod(ss+6, &e);
2255 if (count < 0.0 || *e != '\0')
2256 return ratelimit_error(log_msgptr,
2257 "\"%s\" is not a positive number", ss);
2258 }
2259 else if (strncmpic(ss, US"unique=", 7) == 0)
2260 unique = string_copy(ss + 7);
2261 else if (key == NULL)
2262 key = string_copy(ss);
2263 else
2264 key = string_sprintf("%s/%s", key, ss);
2265 }
2266
2267 /* Sanity check. When the badacl flag is set the update mode must either
2268 be readonly (which is the default if it is omitted) or, for backwards
2269 compatibility, a combination of noupdate and strict or leaky. */
2270
2271 if (mode == RATE_PER_CLASH)
2272 return ratelimit_error(log_msgptr, "conflicting per_* options");
2273 if (leaky + strict + readonly > 1)
2274 return ratelimit_error(log_msgptr, "conflicting update modes");
2275 if (badacl && (leaky || strict) && !noupdate)
2276 return ratelimit_error(log_msgptr,
2277 "\"%s\" must not have /leaky or /strict option in %s ACL",
2278 ratelimit_option_string[mode], acl_wherenames[where]);
2279
2280 /* Set the default values of any unset options. In readonly mode we
2281 perform the rate computation without any increment so that its value
2282 decays to eventually allow over-limit senders through. */
2283
2284 if (noupdate) readonly = TRUE, leaky = strict = FALSE;
2285 if (badacl) readonly = TRUE;
2286 if (readonly) count = 0.0;
2287 if (!strict && !readonly) leaky = TRUE;
2288 if (mode == RATE_PER_WHAT) mode = RATE_PER_MAIL;
2289
2290 /* Create the lookup key. If there is no explicit key, use sender_host_address.
2291 If there is no sender_host_address (e.g. -bs or acl_not_smtp) then we simply
2292 omit it. The smoothing constant (sender_rate_period) and the per_xxx options
2293 are added to the key because they alter the meaning of the stored data. */
2294
2295 if (key == NULL)
2296 key = (sender_host_address == NULL)? US"" : sender_host_address;
2297
2298 key = string_sprintf("%s/%s/%s%s",
2299 sender_rate_period,
2300 ratelimit_option_string[mode],
2301 unique == NULL ? "" : "unique/",
2302 key);
2303
2304 HDEBUG(D_acl)
2305 debug_printf_indent("ratelimit condition count=%.0f %.1f/%s\n", count, limit, key);
2306
2307 /* See if we have already computed the rate by looking in the relevant tree.
2308 For per-connection rate limiting, store tree nodes and dbdata in the permanent
2309 pool so that they survive across resets. In readonly mode we only remember the
2310 result for the rest of this command in case a later command changes it. After
2311 this bit of logic the code is independent of the per_* mode. */
2312
2313 old_pool = store_pool;
2314
2315 if (readonly)
2316 anchor = &ratelimiters_cmd;
2317 else switch(mode) {
2318 case RATE_PER_CONN:
2319 anchor = &ratelimiters_conn;
2320 store_pool = POOL_PERM;
2321 break;
2322 case RATE_PER_BYTE:
2323 case RATE_PER_MAIL:
2324 case RATE_PER_ALLRCPTS:
2325 anchor = &ratelimiters_mail;
2326 break;
2327 case RATE_PER_ADDR:
2328 case RATE_PER_CMD:
2329 case RATE_PER_RCPT:
2330 anchor = &ratelimiters_cmd;
2331 break;
2332 default:
2333 anchor = NULL; /* silence an "unused" complaint */
2334 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2335 "internal ACL error: unknown ratelimit mode %d", mode);
2336 break;
2337 }
2338
2339 t = tree_search(*anchor, key);
2340 if (t != NULL)
2341 {
2342 dbd = t->data.ptr;
2343 /* The following few lines duplicate some of the code below. */
2344 rc = (dbd->rate < limit)? FAIL : OK;
2345 store_pool = old_pool;
2346 sender_rate = string_sprintf("%.1f", dbd->rate);
2347 HDEBUG(D_acl)
2348 debug_printf_indent("ratelimit found pre-computed rate %s\n", sender_rate);
2349 return rc;
2350 }
2351
2352 /* We aren't using a pre-computed rate, so get a previously recorded rate
2353 from the database, which will be updated and written back if required. */
2354
2355 dbm = dbfn_open(US"ratelimit", O_RDWR, &dbblock, TRUE);
2356 if (dbm == NULL)
2357 {
2358 store_pool = old_pool;
2359 sender_rate = NULL;
2360 HDEBUG(D_acl) debug_printf_indent("ratelimit database not available\n");
2361 *log_msgptr = US"ratelimit database not available";
2362 return DEFER;
2363 }
2364 dbdb = dbfn_read_with_length(dbm, key, &dbdb_size);
2365 dbd = NULL;
2366
2367 gettimeofday(&tv, NULL);
2368
2369 if (dbdb != NULL)
2370 {
2371 /* Locate the basic ratelimit block inside the DB data. */
2372 HDEBUG(D_acl) debug_printf_indent("ratelimit found key in database\n");
2373 dbd = &dbdb->dbd;
2374
2375 /* Forget the old Bloom filter if it is too old, so that we count each
2376 repeating event once per period. We don't simply clear and re-use the old
2377 filter because we want its size to change if the limit changes. Note that
2378 we keep the dbd pointer for copying the rate into the new data block. */
2379
2380 if(unique != NULL && tv.tv_sec > dbdb->bloom_epoch + period)
2381 {
2382 HDEBUG(D_acl) debug_printf_indent("ratelimit discarding old Bloom filter\n");
2383 dbdb = NULL;
2384 }
2385
2386 /* Sanity check. */
2387
2388 if(unique != NULL && dbdb_size < sizeof(*dbdb))
2389 {
2390 HDEBUG(D_acl) debug_printf_indent("ratelimit discarding undersize Bloom filter\n");
2391 dbdb = NULL;
2392 }
2393 }
2394
2395 /* Allocate a new data block if the database lookup failed
2396 or the Bloom filter passed its age limit. */
2397
2398 if (dbdb == NULL)
2399 {
2400 if (unique == NULL)
2401 {
2402 /* No Bloom filter. This basic ratelimit block is initialized below. */
2403 HDEBUG(D_acl) debug_printf_indent("ratelimit creating new rate data block\n");
2404 dbdb_size = sizeof(*dbd);
2405 dbdb = store_get(dbdb_size);
2406 }
2407 else
2408 {
2409 int extra;
2410 HDEBUG(D_acl) debug_printf_indent("ratelimit creating new Bloom filter\n");
2411
2412 /* See the long comment below for an explanation of the magic number 2.
2413 The filter has a minimum size in case the rate limit is very small;
2414 this is determined by the definition of dbdata_ratelimit_unique. */
2415
2416 extra = (int)limit * 2 - sizeof(dbdb->bloom);
2417 if (extra < 0) extra = 0;
2418 dbdb_size = sizeof(*dbdb) + extra;
2419 dbdb = store_get(dbdb_size);
2420 dbdb->bloom_epoch = tv.tv_sec;
2421 dbdb->bloom_size = sizeof(dbdb->bloom) + extra;
2422 memset(dbdb->bloom, 0, dbdb->bloom_size);
2423
2424 /* Preserve any basic ratelimit data (which is our longer-term memory)
2425 by copying it from the discarded block. */
2426
2427 if (dbd != NULL)
2428 {
2429 dbdb->dbd = *dbd;
2430 dbd = &dbdb->dbd;
2431 }
2432 }
2433 }
2434
2435 /* If we are counting unique events, find out if this event is new or not.
2436 If the client repeats the event during the current period then it should be
2437 counted. We skip this code in readonly mode for efficiency, because any
2438 changes to the filter will be discarded and because count is already set to
2439 zero. */
2440
2441 if (unique != NULL && !readonly)
2442 {
2443 /* We identify unique events using a Bloom filter. (You can find my
2444 notes on Bloom filters at http://fanf.livejournal.com/81696.html)
2445 With the per_addr option, an "event" is a recipient address, though the
2446 user can use the unique option to define their own events. We only count
2447 an event if we have not seen it before.
2448
2449 We size the filter according to the rate limit, which (in leaky mode)
2450 is the limit on the population of the filter. We allow 16 bits of space
2451 per entry (see the construction code above) and we set (up to) 8 of them
2452 when inserting an element (see the loop below). The probability of a false
2453 positive (an event we have not seen before but which we fail to count) is
2454
2455 size = limit * 16
2456 numhash = 8
2457 allzero = exp(-numhash * pop / size)
2458 = exp(-0.5 * pop / limit)
2459 fpr = pow(1 - allzero, numhash)
2460
2461 For senders at the limit the fpr is 0.06% or 1 in 1700
2462 and for senders at half the limit it is 0.0006% or 1 in 170000
2463
2464 In strict mode the Bloom filter can fill up beyond the normal limit, in
2465 which case the false positive rate will rise. This means that the
2466 measured rate for very fast senders can bogusly drop off after a while.
2467
2468 At twice the limit, the fpr is 2.5% or 1 in 40
2469 At four times the limit, it is 31% or 1 in 3.2
2470
2471 It takes ln(pop/limit) periods for an over-limit burst of pop events to
2472 decay below the limit, and if this is more than one then the Bloom filter
2473 will be discarded before the decay gets that far. The false positive rate
2474 at this threshold is 9.3% or 1 in 10.7. */
2475
2476 BOOL seen;
2477 unsigned n, hash, hinc;
2478 uschar md5sum[16];
2479 md5 md5info;
2480
2481 /* Instead of using eight independent hash values, we combine two values
2482 using the formula h1 + n * h2. This does not harm the Bloom filter's
2483 performance, and means the amount of hash we need is independent of the
2484 number of bits we set in the filter. */
2485
2486 md5_start(&md5info);
2487 md5_end(&md5info, unique, Ustrlen(unique), md5sum);
2488 hash = md5sum[0] | md5sum[1] << 8 | md5sum[2] << 16 | md5sum[3] << 24;
2489 hinc = md5sum[4] | md5sum[5] << 8 | md5sum[6] << 16 | md5sum[7] << 24;
2490
2491 /* Scan the bits corresponding to this event. A zero bit means we have
2492 not seen it before. Ensure all bits are set to record this event. */
2493
2494 HDEBUG(D_acl) debug_printf_indent("ratelimit checking uniqueness of %s\n", unique);
2495
2496 seen = TRUE;
2497 for (n = 0; n < 8; n++, hash += hinc)
2498 {
2499 int bit = 1 << (hash % 8);
2500 int byte = (hash / 8) % dbdb->bloom_size;
2501 if ((dbdb->bloom[byte] & bit) == 0)
2502 {
2503 dbdb->bloom[byte] |= bit;
2504 seen = FALSE;
2505 }
2506 }
2507
2508 /* If this event has occurred before, do not count it. */
2509
2510 if (seen)
2511 {
2512 HDEBUG(D_acl) debug_printf_indent("ratelimit event found in Bloom filter\n");
2513 count = 0.0;
2514 }
2515 else
2516 HDEBUG(D_acl) debug_printf_indent("ratelimit event added to Bloom filter\n");
2517 }
2518
2519 /* If there was no previous ratelimit data block for this key, initialize
2520 the new one, otherwise update the block from the database. The initial rate
2521 is what would be computed by the code below for an infinite interval. */
2522
2523 if (dbd == NULL)
2524 {
2525 HDEBUG(D_acl) debug_printf_indent("ratelimit initializing new key's rate data\n");
2526 dbd = &dbdb->dbd;
2527 dbd->time_stamp = tv.tv_sec;
2528 dbd->time_usec = tv.tv_usec;
2529 dbd->rate = count;
2530 }
2531 else
2532 {
2533 /* The smoothed rate is computed using an exponentially weighted moving
2534 average adjusted for variable sampling intervals. The standard EWMA for
2535 a fixed sampling interval is: f'(t) = (1 - a) * f(t) + a * f'(t - 1)
2536 where f() is the measured value and f'() is the smoothed value.
2537
2538 Old data decays out of the smoothed value exponentially, such that data n
2539 samples old is multiplied by a^n. The exponential decay time constant p
2540 is defined such that data p samples old is multiplied by 1/e, which means
2541 that a = exp(-1/p). We can maintain the same time constant for a variable
2542 sampling interval i by using a = exp(-i/p).
2543
2544 The rate we are measuring is messages per period, suitable for directly
2545 comparing with the limit. The average rate between now and the previous
2546 message is period / interval, which we feed into the EWMA as the sample.
2547
2548 It turns out that the number of messages required for the smoothed rate
2549 to reach the limit when they are sent in a burst is equal to the limit.
2550 This can be seen by analysing the value of the smoothed rate after N
2551 messages sent at even intervals. Let k = (1 - a) * p/i
2552
2553 rate_1 = (1 - a) * p/i + a * rate_0
2554 = k + a * rate_0
2555 rate_2 = k + a * rate_1
2556 = k + a * k + a^2 * rate_0
2557 rate_3 = k + a * k + a^2 * k + a^3 * rate_0
2558 rate_N = rate_0 * a^N + k * SUM(x=0..N-1)(a^x)
2559 = rate_0 * a^N + k * (1 - a^N) / (1 - a)
2560 = rate_0 * a^N + p/i * (1 - a^N)
2561
2562 When N is large, a^N -> 0 so rate_N -> p/i as desired.
2563
2564 rate_N = p/i + (rate_0 - p/i) * a^N
2565 a^N = (rate_N - p/i) / (rate_0 - p/i)
2566 N * -i/p = log((rate_N - p/i) / (rate_0 - p/i))
2567 N = p/i * log((rate_0 - p/i) / (rate_N - p/i))
2568
2569 Numerical analysis of the above equation, setting the computed rate to
2570 increase from rate_0 = 0 to rate_N = limit, shows that for large sending
2571 rates, p/i, the number of messages N = limit. So limit serves as both the
2572 maximum rate measured in messages per period, and the maximum number of
2573 messages that can be sent in a fast burst. */
2574
2575 double this_time = (double)tv.tv_sec
2576 + (double)tv.tv_usec / 1000000.0;
2577 double prev_time = (double)dbd->time_stamp
2578 + (double)dbd->time_usec / 1000000.0;
2579
2580 /* We must avoid division by zero, and deal gracefully with the clock going
2581 backwards. If we blunder ahead when time is in reverse then the computed
2582 rate will be bogus. To be safe we clamp interval to a very small number. */
2583
2584 double interval = this_time - prev_time <= 0.0 ? 1e-9
2585 : this_time - prev_time;
2586
2587 double i_over_p = interval / period;
2588 double a = exp(-i_over_p);
2589
2590 /* Combine the instantaneous rate (period / interval) with the previous rate
2591 using the smoothing factor a. In order to measure sized events, multiply the
2592 instantaneous rate by the count of bytes or recipients etc. */
2593
2594 dbd->time_stamp = tv.tv_sec;
2595 dbd->time_usec = tv.tv_usec;
2596 dbd->rate = (1 - a) * count / i_over_p + a * dbd->rate;
2597
2598 /* When events are very widely spaced the computed rate tends towards zero.
2599 Although this is accurate it turns out not to be useful for our purposes,
2600 especially when the first event after a long silence is the start of a spam
2601 run. A more useful model is that the rate for an isolated event should be the
2602 size of the event per the period size, ignoring the lack of events outside
2603 the current period and regardless of where the event falls in the period. So,
2604 if the interval was so long that the calculated rate is unhelpfully small, we
2605 re-initialize the rate. In the absence of higher-rate bursts, the condition
2606 below is true if the interval is greater than the period. */
2607
2608 if (dbd->rate < count) dbd->rate = count;
2609 }
2610
2611 /* Clients sending at the limit are considered to be over the limit.
2612 This matters for edge cases such as a limit of zero, when the client
2613 should be completely blocked. */
2614
2615 rc = (dbd->rate < limit)? FAIL : OK;
2616
2617 /* Update the state if the rate is low or if we are being strict. If we
2618 are in leaky mode and the sender's rate is too high, we do not update
2619 the recorded rate in order to avoid an over-aggressive sender's retry
2620 rate preventing them from getting any email through. If readonly is set,
2621 neither leaky nor strict are set, so we do not do any updates. */
2622
2623 if ((rc == FAIL && leaky) || strict)
2624 {
2625 dbfn_write(dbm, key, dbdb, dbdb_size);
2626 HDEBUG(D_acl) debug_printf_indent("ratelimit db updated\n");
2627 }
2628 else
2629 {
2630 HDEBUG(D_acl) debug_printf_indent("ratelimit db not updated: %s\n",
2631 readonly? "readonly mode" : "over the limit, but leaky");
2632 }
2633
2634 dbfn_close(dbm);
2635
2636 /* Store the result in the tree for future reference. */
2637
2638 t = store_get(sizeof(tree_node) + Ustrlen(key));
2639 t->data.ptr = dbd;
2640 Ustrcpy(t->name, key);
2641 (void)tree_insertnode(anchor, t);
2642
2643 /* We create the formatted version of the sender's rate very late in
2644 order to ensure that it is done using the correct storage pool. */
2645
2646 store_pool = old_pool;
2647 sender_rate = string_sprintf("%.1f", dbd->rate);
2648
2649 HDEBUG(D_acl)
2650 debug_printf_indent("ratelimit computed rate %s\n", sender_rate);
2651
2652 return rc;
2653 }
2654
2655
2656
2657 /*************************************************
2658 * The udpsend ACL modifier *
2659 *************************************************/
2660
2661 /* Called by acl_check_condition() below.
2662
2663 Arguments:
2664 arg the option string for udpsend=
2665 log_msgptr for error messages
2666
2667 Returns: OK - Completed.
2668 DEFER - Problem with DNS lookup.
2669 ERROR - Syntax error in options.
2670 */
2671
2672 static int
2673 acl_udpsend(const uschar *arg, uschar **log_msgptr)
2674 {
2675 int sep = 0;
2676 uschar *hostname;
2677 uschar *portstr;
2678 uschar *portend;
2679 host_item *h;
2680 int portnum;
2681 int len;
2682 int r, s;
2683 uschar * errstr;
2684
2685 hostname = string_nextinlist(&arg, &sep, NULL, 0);
2686 portstr = string_nextinlist(&arg, &sep, NULL, 0);
2687
2688 if (!hostname)
2689 {
2690 *log_msgptr = US"missing destination host in \"udpsend\" modifier";
2691 return ERROR;
2692 }
2693 if (!portstr)
2694 {
2695 *log_msgptr = US"missing destination port in \"udpsend\" modifier";
2696 return ERROR;
2697 }
2698 if (!arg)
2699 {
2700 *log_msgptr = US"missing datagram payload in \"udpsend\" modifier";
2701 return ERROR;
2702 }
2703 portnum = Ustrtol(portstr, &portend, 10);
2704 if (*portend != '\0')
2705 {
2706 *log_msgptr = US"bad destination port in \"udpsend\" modifier";
2707 return ERROR;
2708 }
2709
2710 /* Make a single-item host list. */
2711 h = store_get(sizeof(host_item));
2712 memset(h, 0, sizeof(host_item));
2713 h->name = hostname;
2714 h->port = portnum;
2715 h->mx = MX_NONE;
2716
2717 if (string_is_ip_address(hostname, NULL))
2718 h->address = hostname, r = HOST_FOUND;
2719 else
2720 r = host_find_byname(h, NULL, 0, NULL, FALSE);
2721 if (r == HOST_FIND_FAILED || r == HOST_FIND_AGAIN)
2722 {
2723 *log_msgptr = US"DNS lookup failed in \"udpsend\" modifier";
2724 return DEFER;
2725 }
2726
2727 HDEBUG(D_acl)
2728 debug_printf_indent("udpsend [%s]:%d %s\n", h->address, portnum, arg);
2729
2730 r = s = ip_connectedsocket(SOCK_DGRAM, h->address, portnum, portnum,
2731 1, NULL, &errstr);
2732 if (r < 0) goto defer;
2733 len = Ustrlen(arg);
2734 r = send(s, arg, len, 0);
2735 if (r < 0)
2736 {
2737 errstr = US strerror(errno);
2738 close(s);
2739 goto defer;
2740 }
2741 close(s);
2742 if (r < len)
2743 {
2744 *log_msgptr =
2745 string_sprintf("\"udpsend\" truncated from %d to %d octets", len, r);
2746 return DEFER;
2747 }
2748
2749 HDEBUG(D_acl)
2750 debug_printf_indent("udpsend %d bytes\n", r);
2751
2752 return OK;
2753
2754 defer:
2755 *log_msgptr = string_sprintf("\"udpsend\" failed: %s", errstr);
2756 return DEFER;
2757 }
2758
2759
2760
2761 /*************************************************
2762 * Handle conditions/modifiers on an ACL item *
2763 *************************************************/
2764
2765 /* Called from acl_check() below.
2766
2767 Arguments:
2768 verb ACL verb
2769 cb ACL condition block - if NULL, result is OK
2770 where where called from
2771 addr the address being checked for RCPT, or NULL
2772 level the nesting level
2773 epp pointer to pass back TRUE if "endpass" encountered
2774 (applies only to "accept" and "discard")
2775 user_msgptr user message pointer
2776 log_msgptr log message pointer
2777 basic_errno pointer to where to put verify error
2778
2779 Returns: OK - all conditions are met
2780 DISCARD - an "acl" condition returned DISCARD - only allowed
2781 for "accept" or "discard" verbs
2782 FAIL - at least one condition fails
2783 FAIL_DROP - an "acl" condition returned FAIL_DROP
2784 DEFER - can't tell at the moment (typically, lookup defer,
2785 but can be temporary callout problem)
2786 ERROR - ERROR from nested ACL or expansion failure or other
2787 error
2788 */
2789
2790 static int
2791 acl_check_condition(int verb, acl_condition_block *cb, int where,
2792 address_item *addr, int level, BOOL *epp, uschar **user_msgptr,
2793 uschar **log_msgptr, int *basic_errno)
2794 {
2795 uschar *user_message = NULL;
2796 uschar *log_message = NULL;
2797 int rc = OK;
2798 #ifdef WITH_CONTENT_SCAN
2799 int sep = -'/';
2800 #endif
2801
2802 for (; cb != NULL; cb = cb->next)
2803 {
2804 const uschar *arg;
2805 int control_type;
2806
2807 /* The message and log_message items set up messages to be used in
2808 case of rejection. They are expanded later. */
2809
2810 if (cb->type == ACLC_MESSAGE)
2811 {
2812 HDEBUG(D_acl) debug_printf_indent(" message: %s\n", cb->arg);
2813 user_message = cb->arg;
2814 continue;
2815 }
2816
2817 if (cb->type == ACLC_LOG_MESSAGE)
2818 {
2819 HDEBUG(D_acl) debug_printf_indent("l_message: %s\n", cb->arg);
2820 log_message = cb->arg;
2821 continue;
2822 }
2823
2824 /* The endpass "condition" just sets a flag to show it occurred. This is
2825 checked at compile time to be on an "accept" or "discard" item. */
2826
2827 if (cb->type == ACLC_ENDPASS)
2828 {
2829 *epp = TRUE;
2830 continue;
2831 }
2832
2833 /* For other conditions and modifiers, the argument is expanded now for some
2834 of them, but not for all, because expansion happens down in some lower level
2835 checking functions in some cases. */
2836
2837 if (!conditions[cb->type].expand_at_top)
2838 arg = cb->arg;
2839 else if (!(arg = expand_string(cb->arg)))
2840 {
2841 if (expand_string_forcedfail) continue;
2842 *log_msgptr = string_sprintf("failed to expand ACL string \"%s\": %s",
2843 cb->arg, expand_string_message);
2844 return search_find_defer ? DEFER : ERROR;
2845 }
2846
2847 /* Show condition, and expanded condition if it's different */
2848
2849 HDEBUG(D_acl)
2850 {
2851 int lhswidth = 0;
2852 debug_printf_indent("check %s%s %n",
2853 (!conditions[cb->type].is_modifier && cb->u.negated)? "!":"",
2854 conditions[cb->type].name, &lhswidth);
2855
2856 if (cb->type == ACLC_SET)
2857 {
2858 debug_printf("acl_%s ", cb->u.varname);
2859 lhswidth += 5 + Ustrlen(cb->u.varname);
2860 }
2861
2862 debug_printf("= %s\n", cb->arg);
2863
2864 if (arg != cb->arg)
2865 debug_printf("%.*s= %s\n", lhswidth,
2866 US" ", CS arg);
2867 }
2868
2869 /* Check that this condition makes sense at this time */
2870
2871 if ((conditions[cb->type].forbids & (1 << where)) != 0)
2872 {
2873 *log_msgptr = string_sprintf("cannot %s %s condition in %s ACL",
2874 conditions[cb->type].is_modifier ? "use" : "test",
2875 conditions[cb->type].name, acl_wherenames[where]);
2876 return ERROR;
2877 }
2878
2879 /* Run the appropriate test for each condition, or take the appropriate
2880 action for the remaining modifiers. */
2881
2882 switch(cb->type)
2883 {
2884 case ACLC_ADD_HEADER:
2885 setup_header(arg);
2886 break;
2887
2888 /* A nested ACL that returns "discard" makes sense only for an "accept" or
2889 "discard" verb. */
2890
2891 case ACLC_ACL:
2892 rc = acl_check_wargs(where, addr, arg, user_msgptr, log_msgptr);
2893 if (rc == DISCARD && verb != ACL_ACCEPT && verb != ACL_DISCARD)
2894 {
2895 *log_msgptr = string_sprintf("nested ACL returned \"discard\" for "
2896 "\"%s\" command (only allowed with \"accept\" or \"discard\")",
2897 verbs[verb]);
2898 return ERROR;
2899 }
2900 break;
2901
2902 case ACLC_AUTHENTICATED:
2903 rc = (sender_host_authenticated == NULL)? FAIL :
2904 match_isinlist(sender_host_authenticated, &arg, 0, NULL, NULL, MCL_STRING,
2905 TRUE, NULL);
2906 break;
2907
2908 #ifdef EXPERIMENTAL_BRIGHTMAIL
2909 case ACLC_BMI_OPTIN:
2910 {
2911 int old_pool = store_pool;
2912 store_pool = POOL_PERM;
2913 bmi_current_optin = string_copy(arg);
2914 store_pool = old_pool;
2915 }
2916 break;
2917 #endif
2918
2919 case ACLC_CONDITION:
2920 /* The true/false parsing here should be kept in sync with that used in
2921 expand.c when dealing with ECOND_BOOL so that we don't have too many
2922 different definitions of what can be a boolean. */
2923 if (*arg == '-'
2924 ? Ustrspn(arg+1, "0123456789") == Ustrlen(arg+1) /* Negative number */
2925 : Ustrspn(arg, "0123456789") == Ustrlen(arg)) /* Digits, or empty */
2926 rc = (Uatoi(arg) == 0)? FAIL : OK;
2927 else
2928 rc = (strcmpic(arg, US"no") == 0 ||
2929 strcmpic(arg, US"false") == 0)? FAIL :
2930 (strcmpic(arg, US"yes") == 0 ||
2931 strcmpic(arg, US"true") == 0)? OK : DEFER;
2932 if (rc == DEFER)
2933 *log_msgptr = string_sprintf("invalid \"condition\" value \"%s\"", arg);
2934 break;
2935
2936 case ACLC_CONTINUE: /* Always succeeds */
2937 break;
2938
2939 case ACLC_CONTROL:
2940 {
2941 const uschar *p = NULL;
2942 control_type = decode_control(arg, &p, where, log_msgptr);
2943
2944 /* Check if this control makes sense at this time */
2945
2946 if (controls_list[control_type].forbids & (1 << where))
2947 {
2948 *log_msgptr = string_sprintf("cannot use \"control=%s\" in %s ACL",
2949 controls_list[control_type].name, acl_wherenames[where]);
2950 return ERROR;
2951 }
2952
2953 switch(control_type)
2954 {
2955 case CONTROL_AUTH_UNADVERTISED:
2956 allow_auth_unadvertised = TRUE;
2957 break;
2958
2959 #ifdef EXPERIMENTAL_BRIGHTMAIL
2960 case CONTROL_BMI_RUN:
2961 bmi_run = 1;
2962 break;
2963 #endif
2964
2965 #ifndef DISABLE_DKIM
2966 case CONTROL_DKIM_VERIFY:
2967 dkim_disable_verify = TRUE;
2968 #ifdef EXPERIMENTAL_DMARC
2969 /* Since DKIM was blocked, skip DMARC too */
2970 dmarc_disable_verify = TRUE;
2971 dmarc_enable_forensic = FALSE;
2972 #endif
2973 break;
2974 #endif
2975
2976 #ifdef EXPERIMENTAL_DMARC
2977 case CONTROL_DMARC_VERIFY:
2978 dmarc_disable_verify = TRUE;
2979 break;
2980
2981 case CONTROL_DMARC_FORENSIC:
2982 dmarc_enable_forensic = TRUE;
2983 break;
2984 #endif
2985
2986 case CONTROL_DSCP:
2987 if (*p == '/')
2988 {
2989 int fd, af, level, optname, value;
2990 /* If we are acting on stdin, the setsockopt may fail if stdin is not
2991 a socket; we can accept that, we'll just debug-log failures anyway. */
2992 fd = fileno(smtp_in);
2993 af = ip_get_address_family(fd);
2994 if (af < 0)
2995 {
2996 HDEBUG(D_acl)
2997 debug_printf_indent("smtp input is probably not a socket [%s], not setting DSCP\n",
2998 strerror(errno));
2999 break;
3000 }
3001 if (dscp_lookup(p+1, af, &level, &optname, &value))
3002 {
3003 if (setsockopt(fd, level, optname, &value, sizeof(value)) < 0)
3004 {
3005 HDEBUG(D_acl) debug_printf_indent("failed to set input DSCP[%s]: %s\n",
3006 p+1, strerror(errno));
3007 }
3008 else
3009 {
3010 HDEBUG(D_acl) debug_printf_indent("set input DSCP to \"%s\"\n", p+1);
3011 }
3012 }
3013 else
3014 {
3015 *log_msgptr = string_sprintf("unrecognised DSCP value in \"control=%s\"", arg);
3016 return ERROR;
3017 }
3018 }
3019 else
3020 {
3021 *log_msgptr = string_sprintf("syntax error in \"control=%s\"", arg);
3022 return ERROR;
3023 }
3024 break;
3025
3026 case CONTROL_ERROR:
3027 return ERROR;
3028
3029 case CONTROL_CASEFUL_LOCAL_PART:
3030 deliver_localpart = addr->cc_local_part;
3031 break;
3032
3033 case CONTROL_CASELOWER_LOCAL_PART:
3034 deliver_localpart = addr->lc_local_part;
3035 break;
3036
3037 case CONTROL_ENFORCE_SYNC:
3038 smtp_enforce_sync = TRUE;
3039 break;
3040
3041 case CONTROL_NO_ENFORCE_SYNC:
3042 smtp_enforce_sync = FALSE;
3043 break;
3044
3045 #ifdef WITH_CONTENT_SCAN
3046 case CONTROL_NO_MBOX_UNSPOOL:
3047 no_mbox_unspool = TRUE;
3048 break;
3049 #endif
3050
3051 case CONTROL_NO_MULTILINE:
3052 no_multiline_responses = TRUE;
3053 break;
3054
3055 case CONTROL_NO_PIPELINING:
3056 pipelining_enable = FALSE;
3057 break;
3058
3059 case CONTROL_NO_DELAY_FLUSH:
3060 disable_delay_flush = TRUE;
3061 break;
3062
3063 case CONTROL_NO_CALLOUT_FLUSH:
3064 disable_callout_flush = TRUE;
3065 break;
3066
3067 case CONTROL_FAKEREJECT:
3068 cancel_cutthrough_connection(TRUE, US"fakereject");
3069 case CONTROL_FAKEDEFER:
3070 fake_response = (control_type == CONTROL_FAKEDEFER) ? DEFER : FAIL;
3071 if (*p == '/')
3072 {
3073 const uschar *pp = p + 1;
3074 while (*pp != 0) pp++;
3075 fake_response_text = expand_string(string_copyn(p+1, pp-p-1));
3076 p = pp;
3077 }
3078 else
3079 {
3080 /* Explicitly reset to default string */
3081 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).";
3082 }
3083 break;
3084
3085 case CONTROL_FREEZE:
3086 deliver_freeze = TRUE;
3087 deliver_frozen_at = time(NULL);
3088 freeze_tell = freeze_tell_config; /* Reset to configured value */
3089 if (Ustrncmp(p, "/no_tell", 8) == 0)
3090 {
3091 p += 8;
3092 freeze_tell = NULL;
3093 }
3094 if (*p != 0)
3095 {
3096 *log_msgptr = string_sprintf("syntax error in \"control=%s\"", arg);
3097 return ERROR;
3098 }
3099 cancel_cutthrough_connection(TRUE, US"item frozen");
3100 break;
3101
3102 case CONTROL_QUEUE_ONLY:
3103 queue_only_policy = TRUE;
3104 cancel_cutthrough_connection(TRUE, US"queueing forced");
3105 break;
3106
3107 case CONTROL_SUBMISSION:
3108 originator_name = US"";
3109 submission_mode = TRUE;
3110 while (*p == '/')
3111 {
3112 if (Ustrncmp(p, "/sender_retain", 14) == 0)
3113 {
3114 p += 14;
3115 active_local_sender_retain = TRUE;
3116 active_local_from_check = FALSE;
3117 }
3118 else if (Ustrncmp(p, "/domain=", 8) == 0)
3119 {
3120 const uschar *pp = p + 8;
3121 while (*pp != 0 && *pp != '/') pp++;
3122 submission_domain = string_copyn(p+8, pp-p-8);
3123 p = pp;
3124 }
3125 /* The name= option must be last, because it swallows the rest of
3126 the string. */
3127 else if (Ustrncmp(p, "/name=", 6) == 0)
3128 {
3129 const uschar *pp = p + 6;
3130 while (*pp != 0) pp++;
3131 submission_name = string_copy(parse_fix_phrase(p+6, pp-p-6,
3132 big_buffer, big_buffer_size));
3133 p = pp;
3134 }
3135 else break;
3136 }
3137 if (*p != 0)
3138 {
3139 *log_msgptr = string_sprintf("syntax error in \"control=%s\"", arg);
3140 return ERROR;
3141 }
3142 break;
3143
3144 case CONTROL_DEBUG:
3145 {
3146 uschar * debug_tag = NULL;
3147 uschar * debug_opts = NULL;
3148 BOOL kill = FALSE;
3149
3150 while (*p == '/')
3151 {
3152 const uschar * pp = p+1;
3153 if (Ustrncmp(pp, "tag=", 4) == 0)
3154 {
3155 for (pp += 4; *pp && *pp != '/';) pp++;
3156 debug_tag = string_copyn(p+5, pp-p-5);
3157 }
3158 else if (Ustrncmp(pp, "opts=", 5) == 0)
3159 {
3160 for (pp += 5; *pp && *pp != '/';) pp++;
3161 debug_opts = string_copyn(p+6, pp-p-6);
3162 }
3163 else if (Ustrncmp(pp, "kill", 4) == 0)
3164 {
3165 for (pp += 4; *pp && *pp != '/';) pp++;
3166 kill = TRUE;
3167 }
3168 else
3169 while (*pp && *pp != '/') pp++;
3170 p = pp;
3171 }
3172
3173 if (kill)
3174 debug_logging_stop();
3175 else
3176 debug_logging_activate(debug_tag, debug_opts);
3177 }
3178 break;
3179
3180 case CONTROL_SUPPRESS_LOCAL_FIXUPS:
3181 suppress_local_fixups = TRUE;
3182 break;
3183
3184 case CONTROL_CUTTHROUGH_DELIVERY:
3185 #ifndef DISABLE_PRDR
3186 if (prdr_requested)
3187 #else
3188 if (0)
3189 #endif
3190 /* Too hard to think about for now. We might in future cutthrough
3191 the case where both sides handle prdr and this-node prdr acl
3192 is "accept" */
3193 *log_msgptr = string_sprintf("PRDR on %s reception\n", arg);
3194 else
3195 {
3196 if (deliver_freeze)
3197 *log_msgptr = US"frozen";
3198 else if (queue_only_policy)
3199 *log_msgptr = US"queue-only";
3200 else if (fake_response == FAIL)
3201 *log_msgptr = US"fakereject";
3202 else
3203 {
3204 if (rcpt_count == 1)
3205 {
3206 cutthrough.delivery = TRUE;
3207 while (*p == '/')
3208 {
3209 const uschar * pp = p+1;
3210 if (Ustrncmp(pp, "defer=", 6) == 0)
3211 {
3212 pp += 6;
3213 if (Ustrncmp(pp, "pass", 4) == 0) cutthrough.defer_pass = TRUE;
3214 /* else if (Ustrncmp(pp, "spool") == 0) ; default */
3215 }
3216 else
3217 while (*pp && *pp != '/') pp++;
3218 p = pp;
3219 }
3220 }
3221 break;
3222 }
3223 *log_msgptr = string_sprintf("\"control=%s\" on %s item",
3224 arg, *log_msgptr);
3225 }
3226 return ERROR;
3227
3228 #ifdef SUPPORT_I18N
3229 case CONTROL_UTF8_DOWNCONVERT:
3230 if (*p == '/')
3231 {
3232 if (p[1] == '1')
3233 {
3234 message_utf8_downconvert = 1;
3235 addr->prop.utf8_downcvt = TRUE;
3236 addr->prop.utf8_downcvt_maybe = FALSE;
3237 p += 2;
3238 break;
3239 }
3240 if (p[1] == '0')
3241 {
3242 message_utf8_downconvert = 0;
3243 addr->prop.utf8_downcvt = FALSE;
3244 addr->prop.utf8_downcvt_maybe = FALSE;
3245 p += 2;
3246 break;
3247 }
3248 if (p[1] == '-' && p[2] == '1')
3249 {
3250 message_utf8_downconvert = -1;
3251 addr->prop.utf8_downcvt = FALSE;
3252 addr->prop.utf8_downcvt_maybe = TRUE;
3253 p += 3;
3254 break;
3255 }
3256 *log_msgptr = US"bad option value for control=utf8_downconvert";
3257 }
3258 else
3259 {
3260 message_utf8_downconvert = 1;
3261 addr->prop.utf8_downcvt = TRUE;
3262 addr->prop.utf8_downcvt_maybe = FALSE;
3263 break;
3264 }
3265 return ERROR;
3266 #endif
3267
3268 }
3269 break;
3270 }
3271
3272 #ifdef EXPERIMENTAL_DCC
3273 case ACLC_DCC:
3274 {
3275 /* Separate the regular expression and any optional parameters. */
3276 const uschar * list = arg;
3277 uschar *ss = string_nextinlist(&list, &sep, big_buffer, big_buffer_size);
3278 /* Run the dcc backend. */
3279 rc = dcc_process(&ss);
3280 /* Modify return code based upon the existence of options. */
3281 while ((ss = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
3282 if (strcmpic(ss, US"defer_ok") == 0 && rc == DEFER)
3283 rc = FAIL; /* FAIL so that the message is passed to the next ACL */
3284 }
3285 break;
3286 #endif
3287
3288 #ifdef WITH_CONTENT_SCAN
3289 case ACLC_DECODE:
3290 rc = mime_decode(&arg);
3291 break;
3292 #endif
3293
3294 case ACLC_DELAY:
3295 {
3296 int delay = readconf_readtime(arg, 0, FALSE);
3297 if (delay < 0)
3298 {
3299 *log_msgptr = string_sprintf("syntax error in argument for \"delay\" "
3300 "modifier: \"%s\" is not a time value", arg);
3301 return ERROR;
3302 }
3303 else
3304 {
3305 HDEBUG(D_acl) debug_printf_indent("delay modifier requests %d-second delay\n",
3306 delay);
3307 if (host_checking)
3308 {
3309 HDEBUG(D_acl)
3310 debug_printf_indent("delay skipped in -bh checking mode\n");
3311 }
3312
3313 /* NOTE 1: Remember that we may be
3314 dealing with stdin/stdout here, in addition to TCP/IP connections.
3315 Also, delays may be specified for non-SMTP input, where smtp_out and
3316 smtp_in will be NULL. Whatever is done must work in all cases.
3317
3318 NOTE 2: The added feature of flushing the output before a delay must
3319 apply only to SMTP input. Hence the test for smtp_out being non-NULL.
3320 */
3321
3322 else
3323 {
3324 if (smtp_out != NULL && !disable_delay_flush)
3325 mac_smtp_fflush();
3326
3327 #if !defined(NO_POLL_H) && defined (POLLRDHUP)
3328 {
3329 struct pollfd p;
3330 nfds_t n = 0;
3331 if (smtp_out)
3332 {
3333 p.fd = fileno(smtp_out);
3334 p.events = POLLRDHUP;
3335 n = 1;
3336 }
3337 if (poll(&p, n, delay*1000) > 0)
3338 HDEBUG(D_acl) debug_printf_indent("delay cancelled by peer close\n");
3339 }
3340 #else
3341 /* It appears to be impossible to detect that a TCP/IP connection has
3342 gone away without reading from it. This means that we cannot shorten
3343 the delay below if the client goes away, because we cannot discover
3344 that the client has closed its end of the connection. (The connection
3345 is actually in a half-closed state, waiting for the server to close its
3346 end.) It would be nice to be able to detect this state, so that the
3347 Exim process is not held up unnecessarily. However, it seems that we
3348 can't. The poll() function does not do the right thing, and in any case
3349 it is not always available.
3350 */
3351
3352 while (delay > 0) delay = sleep(delay);
3353 #endif
3354 }
3355 }
3356 }
3357 break;
3358
3359 #ifndef DISABLE_DKIM
3360 case ACLC_DKIM_SIGNER:
3361 if (dkim_cur_signer != NULL)
3362 rc = match_isinlist(dkim_cur_signer,
3363 &arg,0,NULL,NULL,MCL_STRING,TRUE,NULL);
3364 else
3365 rc = FAIL;
3366 break;
3367
3368 case ACLC_DKIM_STATUS:
3369 rc = match_isinlist(dkim_exim_expand_query(DKIM_VERIFY_STATUS),
3370 &arg,0,NULL,NULL,MCL_STRING,TRUE,NULL);
3371 break;
3372 #endif
3373
3374 #ifdef EXPERIMENTAL_DMARC
3375 case ACLC_DMARC_STATUS:
3376 if (!dmarc_has_been_checked)
3377 dmarc_process();
3378 dmarc_has_been_checked = TRUE;
3379 /* used long way of dmarc_exim_expand_query() in case we need more
3380 * view into the process in the future. */
3381 rc = match_isinlist(dmarc_exim_expand_query(DMARC_VERIFY_STATUS),
3382 &arg,0,NULL,NULL,MCL_STRING,TRUE,NULL);
3383 break;
3384 #endif
3385
3386 case ACLC_DNSLISTS:
3387 rc = verify_check_dnsbl(where, &arg, log_msgptr);
3388 break;
3389
3390 case ACLC_DOMAINS:
3391 rc = match_isinlist(addr->domain, &arg, 0, &domainlist_anchor,
3392 addr->domain_cache, MCL_DOMAIN, TRUE, CUSS &deliver_domain_data);
3393 break;
3394
3395 /* The value in tls_cipher is the full cipher name, for example,
3396 TLSv1:DES-CBC3-SHA:168, whereas the values to test for are just the
3397 cipher names such as DES-CBC3-SHA. But program defensively. We don't know
3398 what may in practice come out of the SSL library - which at the time of
3399 writing is poorly documented. */
3400
3401 case ACLC_ENCRYPTED:
3402 if (tls_in.cipher == NULL) rc = FAIL; else
3403 {
3404 uschar *endcipher = NULL;
3405 uschar *cipher = Ustrchr(tls_in.cipher, ':');
3406 if (cipher == NULL) cipher = tls_in.cipher; else
3407 {
3408 endcipher = Ustrchr(++cipher, ':');
3409 if (endcipher != NULL) *endcipher = 0;
3410 }
3411 rc = match_isinlist(cipher, &arg, 0, NULL, NULL, MCL_STRING, TRUE, NULL);
3412 if (endcipher != NULL) *endcipher = ':';
3413 }
3414 break;
3415
3416 /* Use verify_check_this_host() instead of verify_check_host() so that
3417 we can pass over &host_data to catch any looked up data. Once it has been
3418 set, it retains its value so that it's still there if another ACL verb
3419 comes through here and uses the cache. However, we must put it into
3420 permanent store in case it is also expected to be used in a subsequent
3421 message in the same SMTP connection. */
3422
3423 case ACLC_HOSTS:
3424 rc = verify_check_this_host(&arg, sender_host_cache, NULL,
3425 (sender_host_address == NULL)? US"" : sender_host_address,
3426 CUSS &host_data);
3427 if (rc == DEFER) *log_msgptr = search_error_message;
3428 if (host_data) host_data = string_copy_malloc(host_data);
3429 break;
3430
3431 case ACLC_LOCAL_PARTS:
3432 rc = match_isinlist(addr->cc_local_part, &arg, 0,
3433 &localpartlist_anchor, addr->localpart_cache, MCL_LOCALPART, TRUE,
3434 CUSS &deliver_localpart_data);
3435 break;
3436
3437 case ACLC_LOG_REJECT_TARGET:
3438 {
3439 int logbits = 0;
3440 int sep