938bea7d9eb13baf55f1928bf09e10d50e36a018
[exim.git] / src / src / acl.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* 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 [ACL_ACCEPT] = US"accept",
26 [ACL_DEFER] = US"defer",
27 [ACL_DENY] = US"deny",
28 [ACL_DISCARD] = US"discard",
29 [ACL_DROP] = US"drop",
30 [ACL_REQUIRE] = US"require",
31 [ACL_WARN] = US"warn"
32 };
33
34 /* For each verb, the conditions for which "message" or "log_message" are used
35 are held as a bitmap. This is to avoid expanding the strings unnecessarily. For
36 "accept", the FAIL case is used only after "endpass", but that is selected in
37 the code. */
38
39 static int msgcond[] = {
40 [ACL_ACCEPT] = BIT(OK) | BIT(FAIL) | BIT(FAIL_DROP),
41 [ACL_DEFER] = BIT(OK),
42 [ACL_DENY] = BIT(OK),
43 [ACL_DISCARD] = BIT(OK) | BIT(FAIL) | BIT(FAIL_DROP),
44 [ACL_DROP] = BIT(OK),
45 [ACL_REQUIRE] = BIT(FAIL) | BIT(FAIL_DROP),
46 [ACL_WARN] = BIT(OK)
47 };
48
49 /* ACL condition and modifier codes - keep in step with the table that
50 follows.
51 down. */
52
53 enum { ACLC_ACL,
54 ACLC_ADD_HEADER,
55 ACLC_AUTHENTICATED,
56 #ifdef EXPERIMENTAL_BRIGHTMAIL
57 ACLC_BMI_OPTIN,
58 #endif
59 ACLC_CONDITION,
60 ACLC_CONTINUE,
61 ACLC_CONTROL,
62 #ifdef EXPERIMENTAL_DCC
63 ACLC_DCC,
64 #endif
65 #ifdef WITH_CONTENT_SCAN
66 ACLC_DECODE,
67 #endif
68 ACLC_DELAY,
69 #ifndef DISABLE_DKIM
70 ACLC_DKIM_SIGNER,
71 ACLC_DKIM_STATUS,
72 #endif
73 #ifdef SUPPORT_DMARC
74 ACLC_DMARC_STATUS,
75 #endif
76 ACLC_DNSLISTS,
77 ACLC_DOMAINS,
78 ACLC_ENCRYPTED,
79 ACLC_ENDPASS,
80 ACLC_HOSTS,
81 ACLC_LOCAL_PARTS,
82 ACLC_LOG_MESSAGE,
83 ACLC_LOG_REJECT_TARGET,
84 ACLC_LOGWRITE,
85 #ifdef WITH_CONTENT_SCAN
86 ACLC_MALWARE,
87 #endif
88 ACLC_MESSAGE,
89 #ifdef WITH_CONTENT_SCAN
90 ACLC_MIME_REGEX,
91 #endif
92 ACLC_QUEUE,
93 ACLC_RATELIMIT,
94 ACLC_RECIPIENTS,
95 #ifdef WITH_CONTENT_SCAN
96 ACLC_REGEX,
97 #endif
98 ACLC_REMOVE_HEADER,
99 ACLC_SENDER_DOMAINS,
100 ACLC_SENDERS,
101 ACLC_SET,
102 #ifdef WITH_CONTENT_SCAN
103 ACLC_SPAM,
104 #endif
105 #ifdef SUPPORT_SPF
106 ACLC_SPF,
107 ACLC_SPF_GUESS,
108 #endif
109 ACLC_UDPSEND,
110 ACLC_VERIFY };
111
112 /* ACL conditions/modifiers: "delay", "control", "continue", "endpass",
113 "message", "log_message", "log_reject_target", "logwrite", "queue" and "set" are
114 modifiers that look like conditions but always return TRUE. They are used for
115 their side effects. */
116
117 typedef struct condition_def {
118 uschar *name;
119
120 /* Flag to indicate the condition/modifier has a string expansion done
121 at the outer level. In the other cases, expansion already occurs in the
122 checking functions. */
123 BOOL expand_at_top:1;
124
125 BOOL is_modifier:1;
126
127 /* Bit map vector of which conditions and modifiers are not allowed at certain
128 times. For each condition and modifier, there's a bitmap of dis-allowed times.
129 For some, it is easier to specify the negation of a small number of allowed
130 times. */
131 unsigned forbids;
132
133 } condition_def;
134
135 static condition_def conditions[] = {
136 [ACLC_ACL] = { US"acl", FALSE, FALSE, 0 },
137
138 [ACLC_ADD_HEADER] = { US"add_header", TRUE, TRUE,
139 (unsigned int)
140 ~(ACL_BIT_MAIL | ACL_BIT_RCPT |
141 ACL_BIT_PREDATA | ACL_BIT_DATA |
142 #ifndef DISABLE_PRDR
143 ACL_BIT_PRDR |
144 #endif
145 ACL_BIT_MIME | ACL_BIT_NOTSMTP |
146 ACL_BIT_DKIM |
147 ACL_BIT_NOTSMTP_START),
148 },
149
150 [ACLC_AUTHENTICATED] = { US"authenticated", FALSE, FALSE,
151 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START |
152 ACL_BIT_CONNECT | ACL_BIT_HELO,
153 },
154 #ifdef EXPERIMENTAL_BRIGHTMAIL
155 [ACLC_BMI_OPTIN] = { US"bmi_optin", TRUE, TRUE,
156 ACL_BIT_AUTH |
157 ACL_BIT_CONNECT | ACL_BIT_HELO |
158 ACL_BIT_DATA | ACL_BIT_MIME |
159 # ifndef DISABLE_PRDR
160 ACL_BIT_PRDR |
161 # endif
162 ACL_BIT_ETRN | ACL_BIT_EXPN |
163 ACL_BIT_MAILAUTH |
164 ACL_BIT_MAIL | ACL_BIT_STARTTLS |
165 ACL_BIT_VRFY | ACL_BIT_PREDATA |
166 ACL_BIT_NOTSMTP_START,
167 },
168 #endif
169 [ACLC_CONDITION] = { US"condition", TRUE, FALSE, 0 },
170 [ACLC_CONTINUE] = { 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 [ACLC_CONTROL] = { US"control", TRUE, TRUE, 0 },
175
176 #ifdef EXPERIMENTAL_DCC
177 [ACLC_DCC] = { US"dcc", TRUE, FALSE,
178 (unsigned int)
179 ~(ACL_BIT_DATA |
180 # ifndef DISABLE_PRDR
181 ACL_BIT_PRDR |
182 # endif
183 ACL_BIT_NOTSMTP),
184 },
185 #endif
186 #ifdef WITH_CONTENT_SCAN
187 [ACLC_DECODE] = { US"decode", TRUE, FALSE, (unsigned int) ~ACL_BIT_MIME },
188
189 #endif
190 [ACLC_DELAY] = { US"delay", TRUE, TRUE, ACL_BIT_NOTQUIT },
191 #ifndef DISABLE_DKIM
192 [ACLC_DKIM_SIGNER] = { US"dkim_signers", TRUE, FALSE, (unsigned int) ~ACL_BIT_DKIM },
193 [ACLC_DKIM_STATUS] = { US"dkim_status", TRUE, FALSE, (unsigned int) ~ACL_BIT_DKIM },
194 #endif
195 #ifdef SUPPORT_DMARC
196 [ACLC_DMARC_STATUS] = { US"dmarc_status", TRUE, FALSE, (unsigned int) ~ACL_BIT_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 [ACLC_DNSLISTS] = { US"dnslists", TRUE, FALSE, 0 },
202
203 [ACLC_DOMAINS] = { US"domains", FALSE, FALSE,
204 (unsigned int)
205 ~(ACL_BIT_RCPT | ACL_BIT_VRFY
206 #ifndef DISABLE_PRDR
207 |ACL_BIT_PRDR
208 #endif
209 ),
210 },
211 [ACLC_ENCRYPTED] = { US"encrypted", FALSE, FALSE,
212 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START |
213 ACL_BIT_HELO,
214 },
215
216 [ACLC_ENDPASS] = { US"endpass", TRUE, TRUE, 0 },
217
218 [ACLC_HOSTS] = { US"hosts", FALSE, FALSE,
219 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START,
220 },
221 [ACLC_LOCAL_PARTS] = { US"local_parts", FALSE, FALSE,
222 (unsigned int)
223 ~(ACL_BIT_RCPT | ACL_BIT_VRFY
224 #ifndef DISABLE_PRDR
225 | ACL_BIT_PRDR
226 #endif
227 ),
228 },
229
230 [ACLC_LOG_MESSAGE] = { US"log_message", TRUE, TRUE, 0 },
231 [ACLC_LOG_REJECT_TARGET] = { US"log_reject_target", TRUE, TRUE, 0 },
232 [ACLC_LOGWRITE] = { US"logwrite", TRUE, TRUE, 0 },
233
234 #ifdef WITH_CONTENT_SCAN
235 [ACLC_MALWARE] = { US"malware", TRUE, FALSE,
236 (unsigned int)
237 ~(ACL_BIT_DATA |
238 # ifndef DISABLE_PRDR
239 ACL_BIT_PRDR |
240 # endif
241 ACL_BIT_NOTSMTP),
242 },
243 #endif
244
245 [ACLC_MESSAGE] = { US"message", TRUE, TRUE, 0 },
246 #ifdef WITH_CONTENT_SCAN
247 [ACLC_MIME_REGEX] = { US"mime_regex", TRUE, FALSE, (unsigned int) ~ACL_BIT_MIME },
248 #endif
249
250 [ACLC_QUEUE] = { US"queue", TRUE, TRUE,
251 ACL_BIT_NOTSMTP |
252 #ifndef DISABLE_PRDR
253 ACL_BIT_PRDR |
254 #endif
255 ACL_BIT_DATA,
256 },
257
258 [ACLC_RATELIMIT] = { US"ratelimit", TRUE, FALSE, 0 },
259 [ACLC_RECIPIENTS] = { US"recipients", FALSE, FALSE, (unsigned int) ~ACL_BIT_RCPT },
260
261 #ifdef WITH_CONTENT_SCAN
262 [ACLC_REGEX] = { US"regex", TRUE, FALSE,
263 (unsigned int)
264 ~(ACL_BIT_DATA |
265 # ifndef DISABLE_PRDR
266 ACL_BIT_PRDR |
267 # endif
268 ACL_BIT_NOTSMTP |
269 ACL_BIT_MIME),
270 },
271
272 #endif
273 [ACLC_REMOVE_HEADER] = { US"remove_header", TRUE, TRUE,
274 (unsigned int)
275 ~(ACL_BIT_MAIL|ACL_BIT_RCPT |
276 ACL_BIT_PREDATA | ACL_BIT_DATA |
277 #ifndef DISABLE_PRDR
278 ACL_BIT_PRDR |
279 #endif
280 ACL_BIT_MIME | ACL_BIT_NOTSMTP |
281 ACL_BIT_NOTSMTP_START),
282 },
283 [ACLC_SENDER_DOMAINS] = { US"sender_domains", FALSE, FALSE,
284 ACL_BIT_AUTH | ACL_BIT_CONNECT |
285 ACL_BIT_HELO |
286 ACL_BIT_MAILAUTH | ACL_BIT_QUIT |
287 ACL_BIT_ETRN | ACL_BIT_EXPN |
288 ACL_BIT_STARTTLS | ACL_BIT_VRFY,
289 },
290 [ACLC_SENDERS] = { US"senders", FALSE, FALSE,
291 ACL_BIT_AUTH | ACL_BIT_CONNECT |
292 ACL_BIT_HELO |
293 ACL_BIT_MAILAUTH | ACL_BIT_QUIT |
294 ACL_BIT_ETRN | ACL_BIT_EXPN |
295 ACL_BIT_STARTTLS | ACL_BIT_VRFY,
296 },
297
298 [ACLC_SET] = { US"set", TRUE, TRUE, 0 },
299
300 #ifdef WITH_CONTENT_SCAN
301 [ACLC_SPAM] = { US"spam", TRUE, FALSE,
302 (unsigned int) ~(ACL_BIT_DATA |
303 # ifndef DISABLE_PRDR
304 ACL_BIT_PRDR |
305 # endif
306 ACL_BIT_NOTSMTP),
307 },
308 #endif
309 #ifdef SUPPORT_SPF
310 [ACLC_SPF] = { US"spf", TRUE, FALSE,
311 ACL_BIT_AUTH | ACL_BIT_CONNECT |
312 ACL_BIT_HELO | ACL_BIT_MAILAUTH |
313 ACL_BIT_ETRN | ACL_BIT_EXPN |
314 ACL_BIT_STARTTLS | ACL_BIT_VRFY |
315 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START,
316 },
317 [ACLC_SPF_GUESS] = { US"spf_guess", TRUE, FALSE,
318 ACL_BIT_AUTH | ACL_BIT_CONNECT |
319 ACL_BIT_HELO | ACL_BIT_MAILAUTH |
320 ACL_BIT_ETRN | ACL_BIT_EXPN |
321 ACL_BIT_STARTTLS | ACL_BIT_VRFY |
322 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START,
323 },
324 #endif
325 [ACLC_UDPSEND] = { US"udpsend", TRUE, TRUE, 0 },
326
327 /* Certain types of verify are always allowed, so we let it through
328 always and check in the verify function itself */
329 [ACLC_VERIFY] = { US"verify", TRUE, FALSE, 0 },
330 };
331
332
333
334 /* Return values from decode_control(); used as index so keep in step
335 with the controls_list table that follows! */
336
337 enum {
338 CONTROL_AUTH_UNADVERTISED,
339 #ifdef EXPERIMENTAL_BRIGHTMAIL
340 CONTROL_BMI_RUN,
341 #endif
342 CONTROL_CASEFUL_LOCAL_PART,
343 CONTROL_CASELOWER_LOCAL_PART,
344 CONTROL_CUTTHROUGH_DELIVERY,
345 CONTROL_DEBUG,
346 #ifndef DISABLE_DKIM
347 CONTROL_DKIM_VERIFY,
348 #endif
349 #ifdef SUPPORT_DMARC
350 CONTROL_DMARC_VERIFY,
351 CONTROL_DMARC_FORENSIC,
352 #endif
353 CONTROL_DSCP,
354 CONTROL_ENFORCE_SYNC,
355 CONTROL_ERROR, /* pseudo-value for decode errors */
356 CONTROL_FAKEDEFER,
357 CONTROL_FAKEREJECT,
358 CONTROL_FREEZE,
359
360 CONTROL_NO_CALLOUT_FLUSH,
361 CONTROL_NO_DELAY_FLUSH,
362 CONTROL_NO_ENFORCE_SYNC,
363 #ifdef WITH_CONTENT_SCAN
364 CONTROL_NO_MBOX_UNSPOOL,
365 #endif
366 CONTROL_NO_MULTILINE,
367 CONTROL_NO_PIPELINING,
368
369 CONTROL_QUEUE_ONLY,
370 CONTROL_SUBMISSION,
371 CONTROL_SUPPRESS_LOCAL_FIXUPS,
372 #ifdef SUPPORT_I18N
373 CONTROL_UTF8_DOWNCONVERT,
374 #endif
375 };
376
377
378
379 /* Structure listing various control arguments, with their characteristics.
380 For each control, there's a bitmap of dis-allowed times. For some, it is easier
381 to specify the negation of a small number of allowed times. */
382
383 typedef struct control_def {
384 uschar *name;
385 BOOL has_option; /* Has /option(s) following */
386 unsigned forbids; /* bitmap of dis-allowed times */
387 } control_def;
388
389 static control_def controls_list[] = {
390 /* name has_option forbids */
391 [CONTROL_AUTH_UNADVERTISED] =
392 { US"allow_auth_unadvertised", FALSE,
393 (unsigned)
394 ~(ACL_BIT_CONNECT | ACL_BIT_HELO)
395 },
396 #ifdef EXPERIMENTAL_BRIGHTMAIL
397 [CONTROL_BMI_RUN] =
398 { US"bmi_run", FALSE, 0 },
399 #endif
400 [CONTROL_CASEFUL_LOCAL_PART] =
401 { US"caseful_local_part", FALSE, (unsigned) ~ACL_BIT_RCPT },
402 [CONTROL_CASELOWER_LOCAL_PART] =
403 { US"caselower_local_part", FALSE, (unsigned) ~ACL_BIT_RCPT },
404 [CONTROL_CUTTHROUGH_DELIVERY] =
405 { US"cutthrough_delivery", TRUE, 0 },
406 [CONTROL_DEBUG] =
407 { US"debug", TRUE, 0 },
408
409 #ifndef DISABLE_DKIM
410 [CONTROL_DKIM_VERIFY] =
411 { US"dkim_disable_verify", FALSE,
412 ACL_BIT_DATA | ACL_BIT_NOTSMTP |
413 # ifndef DISABLE_PRDR
414 ACL_BIT_PRDR |
415 # endif
416 ACL_BIT_NOTSMTP_START
417 },
418 #endif
419
420 #ifdef SUPPORT_DMARC
421 [CONTROL_DMARC_VERIFY] =
422 { US"dmarc_disable_verify", FALSE,
423 ACL_BIT_DATA | ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START
424 },
425 [CONTROL_DMARC_FORENSIC] =
426 { US"dmarc_enable_forensic", FALSE,
427 ACL_BIT_DATA | ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START
428 },
429 #endif
430
431 [CONTROL_DSCP] =
432 { US"dscp", TRUE,
433 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START | ACL_BIT_NOTQUIT
434 },
435 [CONTROL_ENFORCE_SYNC] =
436 { US"enforce_sync", FALSE,
437 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START
438 },
439
440 /* Pseudo-value for decode errors */
441 [CONTROL_ERROR] =
442 { US"error", FALSE, 0 },
443
444 [CONTROL_FAKEDEFER] =
445 { US"fakedefer", TRUE,
446 (unsigned)
447 ~(ACL_BIT_MAIL | ACL_BIT_RCPT |
448 ACL_BIT_PREDATA | ACL_BIT_DATA |
449 #ifndef DISABLE_PRDR
450 ACL_BIT_PRDR |
451 #endif
452 ACL_BIT_MIME)
453 },
454 [CONTROL_FAKEREJECT] =
455 { US"fakereject", TRUE,
456 (unsigned)
457 ~(ACL_BIT_MAIL | ACL_BIT_RCPT |
458 ACL_BIT_PREDATA | ACL_BIT_DATA |
459 #ifndef DISABLE_PRDR
460 ACL_BIT_PRDR |
461 #endif
462 ACL_BIT_MIME)
463 },
464 [CONTROL_FREEZE] =
465 { US"freeze", TRUE,
466 (unsigned)
467 ~(ACL_BIT_MAIL | ACL_BIT_RCPT |
468 ACL_BIT_PREDATA | ACL_BIT_DATA |
469 // ACL_BIT_PRDR| /* Not allow one user to freeze for all */
470 ACL_BIT_NOTSMTP | ACL_BIT_MIME)
471 },
472
473 [CONTROL_NO_CALLOUT_FLUSH] =
474 { US"no_callout_flush", FALSE,
475 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START
476 },
477 [CONTROL_NO_DELAY_FLUSH] =
478 { US"no_delay_flush", FALSE,
479 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START
480 },
481
482 [CONTROL_NO_ENFORCE_SYNC] =
483 { US"no_enforce_sync", FALSE,
484 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START
485 },
486 #ifdef WITH_CONTENT_SCAN
487 [CONTROL_NO_MBOX_UNSPOOL] =
488 { US"no_mbox_unspool", FALSE,
489 (unsigned)
490 ~(ACL_BIT_MAIL | ACL_BIT_RCPT |
491 ACL_BIT_PREDATA | ACL_BIT_DATA |
492 // ACL_BIT_PRDR| /* Not allow one user to freeze for all */
493 ACL_BIT_MIME)
494 },
495 #endif
496 [CONTROL_NO_MULTILINE] =
497 { US"no_multiline_responses", FALSE,
498 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START
499 },
500 [CONTROL_NO_PIPELINING] =
501 { US"no_pipelining", FALSE,
502 ACL_BIT_NOTSMTP | ACL_BIT_NOTSMTP_START
503 },
504
505 [CONTROL_QUEUE_ONLY] =
506 { US"queue_only", FALSE,
507 (unsigned)
508 ~(ACL_BIT_MAIL | ACL_BIT_RCPT |
509 ACL_BIT_PREDATA | ACL_BIT_DATA |
510 // ACL_BIT_PRDR| /* Not allow one user to freeze for all */
511 ACL_BIT_NOTSMTP | ACL_BIT_MIME)
512 },
513
514
515 [CONTROL_SUBMISSION] =
516 { US"submission", TRUE,
517 (unsigned)
518 ~(ACL_BIT_MAIL | ACL_BIT_RCPT | ACL_BIT_PREDATA)
519 },
520 [CONTROL_SUPPRESS_LOCAL_FIXUPS] =
521 { US"suppress_local_fixups", FALSE,
522 (unsigned)
523 ~(ACL_BIT_MAIL | ACL_BIT_RCPT | ACL_BIT_PREDATA |
524 ACL_BIT_NOTSMTP_START)
525 },
526 #ifdef SUPPORT_I18N
527 [CONTROL_UTF8_DOWNCONVERT] =
528 { US"utf8_downconvert", TRUE, (unsigned) ~(ACL_BIT_RCPT | ACL_BIT_VRFY)
529 }
530 #endif
531 };
532
533 /* Support data structures for Client SMTP Authorization. acl_verify_csa()
534 caches its result in a tree to avoid repeated DNS queries. The result is an
535 integer code which is used as an index into the following tables of
536 explanatory strings and verification return codes. */
537
538 static tree_node *csa_cache = NULL;
539
540 enum { CSA_UNKNOWN, CSA_OK, CSA_DEFER_SRV, CSA_DEFER_ADDR,
541 CSA_FAIL_EXPLICIT, CSA_FAIL_DOMAIN, CSA_FAIL_NOADDR, CSA_FAIL_MISMATCH };
542
543 /* The acl_verify_csa() return code is translated into an acl_verify() return
544 code using the following table. It is OK unless the client is definitely not
545 authorized. This is because CSA is supposed to be optional for sending sites,
546 so recipients should not be too strict about checking it - especially because
547 DNS problems are quite likely to occur. It's possible to use $csa_status in
548 further ACL conditions to distinguish ok, unknown, and defer if required, but
549 the aim is to make the usual configuration simple. */
550
551 static int csa_return_code[] = {
552 [CSA_UNKNOWN] = OK,
553 [CSA_OK] = OK,
554 [CSA_DEFER_SRV] = OK,
555 [CSA_DEFER_ADDR] = OK,
556 [CSA_FAIL_EXPLICIT] = FAIL,
557 [CSA_FAIL_DOMAIN] = FAIL,
558 [CSA_FAIL_NOADDR] = FAIL,
559 [CSA_FAIL_MISMATCH] = FAIL
560 };
561
562 static uschar *csa_status_string[] = {
563 [CSA_UNKNOWN] = US"unknown",
564 [CSA_OK] = US"ok",
565 [CSA_DEFER_SRV] = US"defer",
566 [CSA_DEFER_ADDR] = US"defer",
567 [CSA_FAIL_EXPLICIT] = US"fail",
568 [CSA_FAIL_DOMAIN] = US"fail",
569 [CSA_FAIL_NOADDR] = US"fail",
570 [CSA_FAIL_MISMATCH] = US"fail"
571 };
572
573 static uschar *csa_reason_string[] = {
574 [CSA_UNKNOWN] = US"unknown",
575 [CSA_OK] = US"ok",
576 [CSA_DEFER_SRV] = US"deferred (SRV lookup failed)",
577 [CSA_DEFER_ADDR] = US"deferred (target address lookup failed)",
578 [CSA_FAIL_EXPLICIT] = US"failed (explicit authorization required)",
579 [CSA_FAIL_DOMAIN] = US"failed (host name not authorized)",
580 [CSA_FAIL_NOADDR] = US"failed (no authorized addresses)",
581 [CSA_FAIL_MISMATCH] = US"failed (client address mismatch)"
582 };
583
584 /* Options for the ratelimit condition. Note that there are two variants of
585 the per_rcpt option, depending on the ACL that is used to measure the rate.
586 However any ACL must be able to look up per_rcpt rates in /noupdate mode,
587 so the two variants must have the same internal representation as well as
588 the same configuration string. */
589
590 enum {
591 RATE_PER_WHAT, RATE_PER_CLASH, RATE_PER_ADDR, RATE_PER_BYTE, RATE_PER_CMD,
592 RATE_PER_CONN, RATE_PER_MAIL, RATE_PER_RCPT, RATE_PER_ALLRCPTS
593 };
594
595 #define RATE_SET(var,new) \
596 (((var) == RATE_PER_WHAT) ? ((var) = RATE_##new) : ((var) = RATE_PER_CLASH))
597
598 static uschar *ratelimit_option_string[] = {
599 [RATE_PER_WHAT] = US"?",
600 [RATE_PER_CLASH] = US"!",
601 [RATE_PER_ADDR] = US"per_addr",
602 [RATE_PER_BYTE] = US"per_byte",
603 [RATE_PER_CMD] = US"per_cmd",
604 [RATE_PER_CONN] = US"per_conn",
605 [RATE_PER_MAIL] = US"per_mail",
606 [RATE_PER_RCPT] = US"per_rcpt",
607 [RATE_PER_ALLRCPTS] = US"per_rcpt"
608 };
609
610 /* Enable recursion between acl_check_internal() and acl_check_condition() */
611
612 static int acl_check_wargs(int, address_item *, const uschar *, uschar **,
613 uschar **);
614
615
616 /*************************************************
617 * Find control in list *
618 *************************************************/
619
620 /* The lists are always in order, so binary chop can be used.
621
622 Arguments:
623 name the control name to search for
624 ol the first entry in the control list
625 last one more than the offset of the last entry in the control list
626
627 Returns: index of a control entry, or -1 if not found
628 */
629
630 static int
631 find_control(const uschar * name, control_def * ol, int last)
632 {
633 for (int first = 0; last > first; )
634 {
635 int middle = (first + last)/2;
636 uschar * s = ol[middle].name;
637 int c = Ustrncmp(name, s, Ustrlen(s));
638 if (c == 0) return middle;
639 else if (c > 0) first = middle + 1;
640 else last = middle;
641 }
642 return -1;
643 }
644
645
646
647 /*************************************************
648 * Pick out condition from list *
649 *************************************************/
650
651 /* Use a binary chop method
652
653 Arguments:
654 name name to find
655 list list of conditions
656 end size of list
657
658 Returns: offset in list, or -1 if not found
659 */
660
661 static int
662 acl_checkcondition(uschar * name, condition_def * list, int end)
663 {
664 for (int start = 0; start < end; )
665 {
666 int mid = (start + end)/2;
667 int c = Ustrcmp(name, list[mid].name);
668 if (c == 0) return mid;
669 if (c < 0) end = mid;
670 else start = mid + 1;
671 }
672 return -1;
673 }
674
675
676 /*************************************************
677 * Pick out name from list *
678 *************************************************/
679
680 /* Use a binary chop method
681
682 Arguments:
683 name name to find
684 list list of names
685 end size of list
686
687 Returns: offset in list, or -1 if not found
688 */
689
690 static int
691 acl_checkname(uschar *name, uschar **list, int end)
692 {
693 for (int start = 0; start < end; )
694 {
695 int mid = (start + end)/2;
696 int c = Ustrcmp(name, list[mid]);
697 if (c == 0) return mid;
698 if (c < 0) end = mid; else start = mid + 1;
699 }
700
701 return -1;
702 }
703
704
705 /*************************************************
706 * Read and parse one ACL *
707 *************************************************/
708
709 /* This function is called both from readconf in order to parse the ACLs in the
710 configuration file, and also when an ACL is encountered dynamically (e.g. as
711 the result of an expansion). It is given a function to call in order to
712 retrieve the lines of the ACL. This function handles skipping comments and
713 blank lines (where relevant).
714
715 Arguments:
716 func function to get next line of ACL
717 error where to put an error message
718
719 Returns: pointer to ACL, or NULL
720 NULL can be legal (empty ACL); in this case error will be NULL
721 */
722
723 acl_block *
724 acl_read(uschar *(*func)(void), uschar **error)
725 {
726 acl_block *yield = NULL;
727 acl_block **lastp = &yield;
728 acl_block *this = NULL;
729 acl_condition_block *cond;
730 acl_condition_block **condp = NULL;
731 uschar * s;
732
733 *error = NULL;
734
735 while ((s = (*func)()) != NULL)
736 {
737 int v, c;
738 BOOL negated = FALSE;
739 uschar *saveline = s;
740 uschar name[64];
741
742 /* Conditions (but not verbs) are allowed to be negated by an initial
743 exclamation mark. */
744
745 while (isspace(*s)) s++;
746 if (*s == '!')
747 {
748 negated = TRUE;
749 s++;
750 }
751
752 /* Read the name of a verb or a condition, or the start of a new ACL, which
753 can be started by a name, or by a macro definition. */
754
755 s = readconf_readname(name, sizeof(name), s);
756 if (*s == ':' || (isupper(name[0]) && *s == '=')) return yield;
757
758 /* If a verb is unrecognized, it may be another condition or modifier that
759 continues the previous verb. */
760
761 if ((v = acl_checkname(name, verbs, nelem(verbs))) < 0)
762 {
763 if (!this)
764 {
765 *error = string_sprintf("unknown ACL verb \"%s\" in \"%s\"", name,
766 saveline);
767 return NULL;
768 }
769 }
770
771 /* New verb */
772
773 else
774 {
775 if (negated)
776 {
777 *error = string_sprintf("malformed ACL line \"%s\"", saveline);
778 return NULL;
779 }
780 this = store_get(sizeof(acl_block), FALSE);
781 *lastp = this;
782 lastp = &(this->next);
783 this->next = NULL;
784 this->condition = NULL;
785 this->verb = v;
786 this->srcline = config_lineno; /* for debug output */
787 this->srcfile = config_filename; /**/
788 condp = &(this->condition);
789 if (*s == 0) continue; /* No condition on this line */
790 if (*s == '!')
791 {
792 negated = TRUE;
793 s++;
794 }
795 s = readconf_readname(name, sizeof(name), s); /* Condition name */
796 }
797
798 /* Handle a condition or modifier. */
799
800 if ((c = acl_checkcondition(name, conditions, nelem(conditions))) < 0)
801 {
802 *error = string_sprintf("unknown ACL condition/modifier in \"%s\"",
803 saveline);
804 return NULL;
805 }
806
807 /* The modifiers may not be negated */
808
809 if (negated && conditions[c].is_modifier)
810 {
811 *error = string_sprintf("ACL error: negation is not allowed with "
812 "\"%s\"", conditions[c].name);
813 return NULL;
814 }
815
816 /* ENDPASS may occur only with ACCEPT or DISCARD. */
817
818 if (c == ACLC_ENDPASS &&
819 this->verb != ACL_ACCEPT &&
820 this->verb != ACL_DISCARD)
821 {
822 *error = string_sprintf("ACL error: \"%s\" is not allowed with \"%s\"",
823 conditions[c].name, verbs[this->verb]);
824 return NULL;
825 }
826
827 cond = store_get(sizeof(acl_condition_block), FALSE);
828 cond->next = NULL;
829 cond->type = c;
830 cond->u.negated = negated;
831
832 *condp = cond;
833 condp = &(cond->next);
834
835 /* The "set" modifier is different in that its argument is "name=value"
836 rather than just a value, and we can check the validity of the name, which
837 gives us a variable name to insert into the data block. The original ACL
838 variable names were acl_c0 ... acl_c9 and acl_m0 ... acl_m9. This was
839 extended to 20 of each type, but after that people successfully argued for
840 arbitrary names. In the new scheme, the names must start with acl_c or acl_m.
841 After that, we allow alphanumerics and underscores, but the first character
842 after c or m must be a digit or an underscore. This retains backwards
843 compatibility. */
844
845 if (c == ACLC_SET)
846 #ifndef DISABLE_DKIM
847 if ( Ustrncmp(s, "dkim_verify_status", 18) == 0
848 || Ustrncmp(s, "dkim_verify_reason", 18) == 0)
849 {
850 uschar * endptr = s+18;
851
852 if (isalnum(*endptr))
853 {
854 *error = string_sprintf("invalid variable name after \"set\" in ACL "
855 "modifier \"set %s\" "
856 "(only \"dkim_verify_status\" or \"dkim_verify_reason\" permitted)",
857 s);
858 return NULL;
859 }
860 cond->u.varname = string_copyn(s, 18);
861 s = endptr;
862 while (isspace(*s)) s++;
863 }
864 else
865 #endif
866 {
867 uschar *endptr;
868
869 if (Ustrncmp(s, "acl_c", 5) != 0 && Ustrncmp(s, "acl_m", 5) != 0)
870 {
871 *error = string_sprintf("invalid variable name after \"set\" in ACL "
872 "modifier \"set %s\" (must start \"acl_c\" or \"acl_m\")", s);
873 return NULL;
874 }
875
876 endptr = s + 5;
877 if (!isdigit(*endptr) && *endptr != '_')
878 {
879 *error = string_sprintf("invalid variable name after \"set\" in ACL "
880 "modifier \"set %s\" (digit or underscore must follow acl_c or acl_m)",
881 s);
882 return NULL;
883 }
884
885 while (*endptr && *endptr != '=' && !isspace(*endptr))
886 {
887 if (!isalnum(*endptr) && *endptr != '_')
888 {
889 *error = string_sprintf("invalid character \"%c\" in variable name "
890 "in ACL modifier \"set %s\"", *endptr, s);
891 return NULL;
892 }
893 endptr++;
894 }
895
896 cond->u.varname = string_copyn(s + 4, endptr - s - 4);
897 s = endptr;
898 while (isspace(*s)) s++;
899 }
900
901 /* For "set", we are now positioned for the data. For the others, only
902 "endpass" has no data */
903
904 if (c != ACLC_ENDPASS)
905 {
906 if (*s++ != '=')
907 {
908 *error = string_sprintf("\"=\" missing after ACL \"%s\" %s", name,
909 conditions[c].is_modifier ? US"modifier" : US"condition");
910 return NULL;
911 }
912 while (isspace(*s)) s++;
913 cond->arg = string_copy(s);
914 }
915 }
916
917 return yield;
918 }
919
920
921
922 /*************************************************
923 * Set up added header line(s) *
924 *************************************************/
925
926 /* This function is called by the add_header modifier, and also from acl_warn()
927 to implement the now-deprecated way of adding header lines using "message" on a
928 "warn" verb. The argument is treated as a sequence of header lines which are
929 added to a chain, provided there isn't an identical one already there.
930
931 Argument: string of header lines
932 Returns: nothing
933 */
934
935 static void
936 setup_header(const uschar *hstring)
937 {
938 const uschar *p, *q;
939 int hlen = Ustrlen(hstring);
940
941 /* Ignore any leading newlines */
942 while (*hstring == '\n') hstring++, hlen--;
943
944 /* An empty string does nothing; ensure exactly one final newline. */
945 if (hlen <= 0) return;
946 if (hstring[--hlen] != '\n') /* no newline */
947 q = string_sprintf("%s\n", hstring);
948 else if (hstring[hlen-1] == '\n') /* double newline */
949 {
950 uschar * s = string_copy(hstring);
951 while(s[--hlen] == '\n')
952 s[hlen+1] = '\0';
953 q = s;
954 }
955 else
956 q = hstring;
957
958 /* Loop for multiple header lines, taking care about continuations */
959
960 for (p = q; *p; p = q)
961 {
962 const uschar *s;
963 uschar * hdr;
964 int newtype = htype_add_bot;
965 header_line **hptr = &acl_added_headers;
966
967 /* Find next header line within the string */
968
969 for (;;)
970 {
971 q = Ustrchr(q, '\n'); /* we know there was a newline */
972 if (*++q != ' ' && *q != '\t') break;
973 }
974
975 /* If the line starts with a colon, interpret the instruction for where to
976 add it. This temporarily sets up a new type. */
977
978 if (*p == ':')
979 {
980 if (strncmpic(p, US":after_received:", 16) == 0)
981 {
982 newtype = htype_add_rec;
983 p += 16;
984 }
985 else if (strncmpic(p, US":at_start_rfc:", 14) == 0)
986 {
987 newtype = htype_add_rfc;
988 p += 14;
989 }
990 else if (strncmpic(p, US":at_start:", 10) == 0)
991 {
992 newtype = htype_add_top;
993 p += 10;
994 }
995 else if (strncmpic(p, US":at_end:", 8) == 0)
996 {
997 newtype = htype_add_bot;
998 p += 8;
999 }
1000 while (*p == ' ' || *p == '\t') p++;
1001 }
1002
1003 /* See if this line starts with a header name, and if not, add X-ACL-Warn:
1004 to the front of it. */
1005
1006 for (s = p; s < q - 1; s++)
1007 if (*s == ':' || !isgraph(*s)) break;
1008
1009 hdr = string_sprintf("%s%.*s", *s == ':' ? "" : "X-ACL-Warn: ", (int) (q - p), p);
1010 hlen = Ustrlen(hdr);
1011
1012 /* See if this line has already been added */
1013
1014 while (*hptr)
1015 {
1016 if (Ustrncmp((*hptr)->text, hdr, hlen) == 0) break;
1017 hptr = &(*hptr)->next;
1018 }
1019
1020 /* Add if not previously present */
1021
1022 if (!*hptr)
1023 {
1024 /* The header_line struct itself is not tainted, though it points to
1025 possibly tainted data. */
1026 header_line * h = store_get(sizeof(header_line), FALSE);
1027 h->text = hdr;
1028 h->next = NULL;
1029 h->type = newtype;
1030 h->slen = hlen;
1031 *hptr = h;
1032 hptr = &h->next;
1033 }
1034 }
1035 }
1036
1037
1038
1039 /*************************************************
1040 * List the added header lines *
1041 *************************************************/
1042 uschar *
1043 fn_hdrs_added(void)
1044 {
1045 gstring * g = NULL;
1046
1047 for (header_line * h = acl_added_headers; h; h = h->next)
1048 {
1049 int i = h->slen;
1050 if (h->text[i-1] == '\n') i--;
1051 g = string_append_listele_n(g, '\n', h->text, i);
1052 }
1053
1054 return g ? g->s : NULL;
1055 }
1056
1057
1058 /*************************************************
1059 * Set up removed header line(s) *
1060 *************************************************/
1061
1062 /* This function is called by the remove_header modifier. The argument is
1063 treated as a sequence of header names which are added to a colon separated
1064 list, provided there isn't an identical one already there.
1065
1066 Argument: string of header names
1067 Returns: nothing
1068 */
1069
1070 static void
1071 setup_remove_header(const uschar *hnames)
1072 {
1073 if (*hnames)
1074 acl_removed_headers = acl_removed_headers
1075 ? string_sprintf("%s : %s", acl_removed_headers, hnames)
1076 : string_copy(hnames);
1077 }
1078
1079
1080
1081 /*************************************************
1082 * Handle warnings *
1083 *************************************************/
1084
1085 /* This function is called when a WARN verb's conditions are true. It adds to
1086 the message's headers, and/or writes information to the log. In each case, this
1087 only happens once (per message for headers, per connection for log).
1088
1089 ** NOTE: The header adding action using the "message" setting is historic, and
1090 its use is now deprecated. The new add_header modifier should be used instead.
1091
1092 Arguments:
1093 where ACL_WHERE_xxxx indicating which ACL this is
1094 user_message message for adding to headers
1095 log_message message for logging, if different
1096
1097 Returns: nothing
1098 */
1099
1100 static void
1101 acl_warn(int where, uschar *user_message, uschar *log_message)
1102 {
1103 if (log_message != NULL && log_message != user_message)
1104 {
1105 uschar *text;
1106 string_item *logged;
1107
1108 text = string_sprintf("%s Warning: %s", host_and_ident(TRUE),
1109 string_printing(log_message));
1110
1111 /* If a sender verification has failed, and the log message is "sender verify
1112 failed", add the failure message. */
1113
1114 if (sender_verified_failed != NULL &&
1115 sender_verified_failed->message != NULL &&
1116 strcmpic(log_message, US"sender verify failed") == 0)
1117 text = string_sprintf("%s: %s", text, sender_verified_failed->message);
1118
1119 /* Search previously logged warnings. They are kept in malloc
1120 store so they can be freed at the start of a new message. */
1121
1122 for (logged = acl_warn_logged; logged; logged = logged->next)
1123 if (Ustrcmp(logged->text, text) == 0) break;
1124
1125 if (!logged)
1126 {
1127 int length = Ustrlen(text) + 1;
1128 log_write(0, LOG_MAIN, "%s", text);
1129 logged = store_malloc(sizeof(string_item) + length);
1130 logged->text = US logged + sizeof(string_item);
1131 memcpy(logged->text, text, length);
1132 logged->next = acl_warn_logged;
1133 acl_warn_logged = logged;
1134 }
1135 }
1136
1137 /* If there's no user message, we are done. */
1138
1139 if (!user_message) return;
1140
1141 /* If this isn't a message ACL, we can't do anything with a user message.
1142 Log an error. */
1143
1144 if (where > ACL_WHERE_NOTSMTP)
1145 {
1146 log_write(0, LOG_MAIN|LOG_PANIC, "ACL \"warn\" with \"message\" setting "
1147 "found in a non-message (%s) ACL: cannot specify header lines here: "
1148 "message ignored", acl_wherenames[where]);
1149 return;
1150 }
1151
1152 /* The code for setting up header lines is now abstracted into a separate
1153 function so that it can be used for the add_header modifier as well. */
1154
1155 setup_header(user_message);
1156 }
1157
1158
1159
1160 /*************************************************
1161 * Verify and check reverse DNS *
1162 *************************************************/
1163
1164 /* Called from acl_verify() below. We look up the host name(s) of the client IP
1165 address if this has not yet been done. The host_name_lookup() function checks
1166 that one of these names resolves to an address list that contains the client IP
1167 address, so we don't actually have to do the check here.
1168
1169 Arguments:
1170 user_msgptr pointer for user message
1171 log_msgptr pointer for log message
1172
1173 Returns: OK verification condition succeeded
1174 FAIL verification failed
1175 DEFER there was a problem verifying
1176 */
1177
1178 static int
1179 acl_verify_reverse(uschar **user_msgptr, uschar **log_msgptr)
1180 {
1181 int rc;
1182
1183 user_msgptr = user_msgptr; /* stop compiler warning */
1184
1185 /* Previous success */
1186
1187 if (sender_host_name != NULL) return OK;
1188
1189 /* Previous failure */
1190
1191 if (host_lookup_failed)
1192 {
1193 *log_msgptr = string_sprintf("host lookup failed%s", host_lookup_msg);
1194 return FAIL;
1195 }
1196
1197 /* Need to do a lookup */
1198
1199 HDEBUG(D_acl)
1200 debug_printf_indent("looking up host name to force name/address consistency check\n");
1201
1202 if ((rc = host_name_lookup()) != OK)
1203 {
1204 *log_msgptr = rc == DEFER
1205 ? US"host lookup deferred for reverse lookup check"
1206 : string_sprintf("host lookup failed for reverse lookup check%s",
1207 host_lookup_msg);
1208 return rc; /* DEFER or FAIL */
1209 }
1210
1211 host_build_sender_fullhost();
1212 return OK;
1213 }
1214
1215
1216
1217 /*************************************************
1218 * Check client IP address matches CSA target *
1219 *************************************************/
1220
1221 /* Called from acl_verify_csa() below. This routine scans a section of a DNS
1222 response for address records belonging to the CSA target hostname. The section
1223 is specified by the reset argument, either RESET_ADDITIONAL or RESET_ANSWERS.
1224 If one of the addresses matches the client's IP address, then the client is
1225 authorized by CSA. If there are target IP addresses but none of them match
1226 then the client is using an unauthorized IP address. If there are no target IP
1227 addresses then the client cannot be using an authorized IP address. (This is
1228 an odd configuration - why didn't the SRV record have a weight of 1 instead?)
1229
1230 Arguments:
1231 dnsa the DNS answer block
1232 dnss a DNS scan block for us to use
1233 reset option specifying what portion to scan, as described above
1234 target the target hostname to use for matching RR names
1235
1236 Returns: CSA_OK successfully authorized
1237 CSA_FAIL_MISMATCH addresses found but none matched
1238 CSA_FAIL_NOADDR no target addresses found
1239 */
1240
1241 static int
1242 acl_verify_csa_address(dns_answer *dnsa, dns_scan *dnss, int reset,
1243 uschar *target)
1244 {
1245 int rc = CSA_FAIL_NOADDR;
1246
1247 for (dns_record * rr = dns_next_rr(dnsa, dnss, reset);
1248 rr;
1249 rr = dns_next_rr(dnsa, dnss, RESET_NEXT))
1250 {
1251 /* Check this is an address RR for the target hostname. */
1252
1253 if (rr->type != T_A
1254 #if HAVE_IPV6
1255 && rr->type != T_AAAA
1256 #endif
1257 ) continue;
1258
1259 if (strcmpic(target, rr->name) != 0) continue;
1260
1261 rc = CSA_FAIL_MISMATCH;
1262
1263 /* Turn the target address RR into a list of textual IP addresses and scan
1264 the list. There may be more than one if it is an A6 RR. */
1265
1266 for (dns_address * da = dns_address_from_rr(dnsa, rr); da; da = da->next)
1267 {
1268 /* If the client IP address matches the target IP address, it's good! */
1269
1270 DEBUG(D_acl) debug_printf_indent("CSA target address is %s\n", da->address);
1271
1272 if (strcmpic(sender_host_address, da->address) == 0) return CSA_OK;
1273 }
1274 }
1275
1276 /* If we found some target addresses but none of them matched, the client is
1277 using an unauthorized IP address, otherwise the target has no authorized IP
1278 addresses. */
1279
1280 return rc;
1281 }
1282
1283
1284
1285 /*************************************************
1286 * Verify Client SMTP Authorization *
1287 *************************************************/
1288
1289 /* Called from acl_verify() below. This routine calls dns_lookup_special()
1290 to find the CSA SRV record corresponding to the domain argument, or
1291 $sender_helo_name if no argument is provided. It then checks that the
1292 client is authorized, and that its IP address corresponds to the SRV
1293 target's address by calling acl_verify_csa_address() above. The address
1294 should have been returned in the DNS response's ADDITIONAL section, but if
1295 not we perform another DNS lookup to get it.
1296
1297 Arguments:
1298 domain pointer to optional parameter following verify = csa
1299
1300 Returns: CSA_UNKNOWN no valid CSA record found
1301 CSA_OK successfully authorized
1302 CSA_FAIL_* client is definitely not authorized
1303 CSA_DEFER_* there was a DNS problem
1304 */
1305
1306 static int
1307 acl_verify_csa(const uschar *domain)
1308 {
1309 tree_node *t;
1310 const uschar *found;
1311 int priority, weight, port;
1312 dns_answer * dnsa = store_get_dns_answer();
1313 dns_scan dnss;
1314 dns_record *rr;
1315 int rc, type;
1316 uschar target[256];
1317
1318 /* Work out the domain we are using for the CSA lookup. The default is the
1319 client's HELO domain. If the client has not said HELO, use its IP address
1320 instead. If it's a local client (exim -bs), CSA isn't applicable. */
1321
1322 while (isspace(*domain) && *domain != '\0') ++domain;
1323 if (*domain == '\0') domain = sender_helo_name;
1324 if (domain == NULL) domain = sender_host_address;
1325 if (sender_host_address == NULL) return CSA_UNKNOWN;
1326
1327 /* If we have an address literal, strip off the framing ready for turning it
1328 into a domain. The framing consists of matched square brackets possibly
1329 containing a keyword and a colon before the actual IP address. */
1330
1331 if (domain[0] == '[')
1332 {
1333 const uschar *start = Ustrchr(domain, ':');
1334 if (start == NULL) start = domain;
1335 domain = string_copyn(start + 1, Ustrlen(start) - 2);
1336 }
1337
1338 /* Turn domains that look like bare IP addresses into domains in the reverse
1339 DNS. This code also deals with address literals and $sender_host_address. It's
1340 not quite kosher to treat bare domains such as EHLO 192.0.2.57 the same as
1341 address literals, but it's probably the most friendly thing to do. This is an
1342 extension to CSA, so we allow it to be turned off for proper conformance. */
1343
1344 if (string_is_ip_address(domain, NULL) != 0)
1345 {
1346 if (!dns_csa_use_reverse) return CSA_UNKNOWN;
1347 domain = dns_build_reverse(domain);
1348 }
1349
1350 /* Find out if we've already done the CSA check for this domain. If we have,
1351 return the same result again. Otherwise build a new cached result structure
1352 for this domain. The name is filled in now, and the value is filled in when
1353 we return from this function. */
1354
1355 t = tree_search(csa_cache, domain);
1356 if (t != NULL) return t->data.val;
1357
1358 t = store_get_perm(sizeof(tree_node) + Ustrlen(domain), is_tainted(domain));
1359 Ustrcpy(t->name, domain);
1360 (void)tree_insertnode(&csa_cache, t);
1361
1362 /* Now we are ready to do the actual DNS lookup(s). */
1363
1364 found = domain;
1365 switch (dns_special_lookup(dnsa, domain, T_CSA, &found))
1366 {
1367 /* If something bad happened (most commonly DNS_AGAIN), defer. */
1368
1369 default:
1370 return t->data.val = CSA_DEFER_SRV;
1371
1372 /* If we found nothing, the client's authorization is unknown. */
1373
1374 case DNS_NOMATCH:
1375 case DNS_NODATA:
1376 return t->data.val = CSA_UNKNOWN;
1377
1378 /* We got something! Go on to look at the reply in more detail. */
1379
1380 case DNS_SUCCEED:
1381 break;
1382 }
1383
1384 /* Scan the reply for well-formed CSA SRV records. */
1385
1386 for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
1387 rr;
1388 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == T_SRV)
1389 {
1390 const uschar * p = rr->data;
1391
1392 /* Extract the numerical SRV fields (p is incremented) */
1393
1394 GETSHORT(priority, p);
1395 GETSHORT(weight, p);
1396 GETSHORT(port, p);
1397
1398 DEBUG(D_acl)
1399 debug_printf_indent("CSA priority=%d weight=%d port=%d\n", priority, weight, port);
1400
1401 /* Check the CSA version number */
1402
1403 if (priority != 1) continue;
1404
1405 /* If the domain does not have a CSA SRV record of its own (i.e. the domain
1406 found by dns_special_lookup() is a parent of the one we asked for), we check
1407 the subdomain assertions in the port field. At the moment there's only one
1408 assertion: legitimate SMTP clients are all explicitly authorized with CSA
1409 SRV records of their own. */
1410
1411 if (Ustrcmp(found, domain) != 0)
1412 return t->data.val = port & 1 ? CSA_FAIL_EXPLICIT : CSA_UNKNOWN;
1413
1414 /* This CSA SRV record refers directly to our domain, so we check the value
1415 in the weight field to work out the domain's authorization. 0 and 1 are
1416 unauthorized; 3 means the client is authorized but we can't check the IP
1417 address in order to authenticate it, so we treat it as unknown; values
1418 greater than 3 are undefined. */
1419
1420 if (weight < 2) return t->data.val = CSA_FAIL_DOMAIN;
1421
1422 if (weight > 2) continue;
1423
1424 /* Weight == 2, which means the domain is authorized. We must check that the
1425 client's IP address is listed as one of the SRV target addresses. Save the
1426 target hostname then break to scan the additional data for its addresses. */
1427
1428 (void)dn_expand(dnsa->answer, dnsa->answer + dnsa->answerlen, p,
1429 (DN_EXPAND_ARG4_TYPE)target, sizeof(target));
1430
1431 DEBUG(D_acl) debug_printf_indent("CSA target is %s\n", target);
1432
1433 break;
1434 }
1435
1436 /* If we didn't break the loop then no appropriate records were found. */
1437
1438 if (!rr) return t->data.val = CSA_UNKNOWN;
1439
1440 /* Do not check addresses if the target is ".", in accordance with RFC 2782.
1441 A target of "." indicates there are no valid addresses, so the client cannot
1442 be authorized. (This is an odd configuration because weight=2 target=. is
1443 equivalent to weight=1, but we check for it in order to keep load off the
1444 root name servers.) Note that dn_expand() turns "." into "". */
1445
1446 if (Ustrcmp(target, "") == 0) return t->data.val = CSA_FAIL_NOADDR;
1447
1448 /* Scan the additional section of the CSA SRV reply for addresses belonging
1449 to the target. If the name server didn't return any additional data (e.g.
1450 because it does not fully support SRV records), we need to do another lookup
1451 to obtain the target addresses; otherwise we have a definitive result. */
1452
1453 rc = acl_verify_csa_address(dnsa, &dnss, RESET_ADDITIONAL, target);
1454 if (rc != CSA_FAIL_NOADDR) return t->data.val = rc;
1455
1456 /* The DNS lookup type corresponds to the IP version used by the client. */
1457
1458 #if HAVE_IPV6
1459 if (Ustrchr(sender_host_address, ':') != NULL)
1460 type = T_AAAA;
1461 else
1462 #endif /* HAVE_IPV6 */
1463 type = T_A;
1464
1465
1466 lookup_dnssec_authenticated = NULL;
1467 switch (dns_lookup(dnsa, target, type, NULL))
1468 {
1469 /* If something bad happened (most commonly DNS_AGAIN), defer. */
1470
1471 default:
1472 return t->data.val = CSA_DEFER_ADDR;
1473
1474 /* If the query succeeded, scan the addresses and return the result. */
1475
1476 case DNS_SUCCEED:
1477 rc = acl_verify_csa_address(dnsa, &dnss, RESET_ANSWERS, target);
1478 if (rc != CSA_FAIL_NOADDR) return t->data.val = rc;
1479 /* else fall through */
1480
1481 /* If the target has no IP addresses, the client cannot have an authorized
1482 IP address. However, if the target site uses A6 records (not AAAA records)
1483 we have to do yet another lookup in order to check them. */
1484
1485 case DNS_NOMATCH:
1486 case DNS_NODATA:
1487 return t->data.val = CSA_FAIL_NOADDR;
1488 }
1489 }
1490
1491
1492
1493 /*************************************************
1494 * Handle verification (address & other) *
1495 *************************************************/
1496
1497 enum { VERIFY_REV_HOST_LKUP, VERIFY_CERT, VERIFY_HELO, VERIFY_CSA, VERIFY_HDR_SYNTAX,
1498 VERIFY_NOT_BLIND, VERIFY_HDR_SNDR, VERIFY_SNDR, VERIFY_RCPT,
1499 VERIFY_HDR_NAMES_ASCII, VERIFY_ARC
1500 };
1501 typedef struct {
1502 uschar * name;
1503 int value;
1504 unsigned where_allowed; /* bitmap */
1505 BOOL no_options; /* Never has /option(s) following */
1506 unsigned alt_opt_sep; /* >0 Non-/ option separator (custom parser) */
1507 } verify_type_t;
1508 static verify_type_t verify_type_list[] = {
1509 /* name value where no-opt opt-sep */
1510 { US"reverse_host_lookup", VERIFY_REV_HOST_LKUP, (unsigned)~0, FALSE, 0 },
1511 { US"certificate", VERIFY_CERT, (unsigned)~0, TRUE, 0 },
1512 { US"helo", VERIFY_HELO, (unsigned)~0, TRUE, 0 },
1513 { US"csa", VERIFY_CSA, (unsigned)~0, FALSE, 0 },
1514 { US"header_syntax", VERIFY_HDR_SYNTAX, ACL_BIT_DATA | ACL_BIT_NOTSMTP, TRUE, 0 },
1515 { US"not_blind", VERIFY_NOT_BLIND, ACL_BIT_DATA | ACL_BIT_NOTSMTP, FALSE, 0 },
1516 { US"header_sender", VERIFY_HDR_SNDR, ACL_BIT_DATA | ACL_BIT_NOTSMTP, FALSE, 0 },
1517 { US"sender", VERIFY_SNDR, ACL_BIT_MAIL | ACL_BIT_RCPT
1518 |ACL_BIT_PREDATA | ACL_BIT_DATA | ACL_BIT_NOTSMTP,
1519 FALSE, 6 },
1520 { US"recipient", VERIFY_RCPT, ACL_BIT_RCPT, FALSE, 0 },
1521 { US"header_names_ascii", VERIFY_HDR_NAMES_ASCII, ACL_BIT_DATA | ACL_BIT_NOTSMTP, TRUE, 0 },
1522 #ifdef EXPERIMENTAL_ARC
1523 { US"arc", VERIFY_ARC, ACL_BIT_DATA, FALSE , 0 },
1524 #endif
1525 };
1526
1527
1528 enum { CALLOUT_DEFER_OK, CALLOUT_NOCACHE, CALLOUT_RANDOM, CALLOUT_USE_SENDER,
1529 CALLOUT_USE_POSTMASTER, CALLOUT_POSTMASTER, CALLOUT_FULLPOSTMASTER,
1530 CALLOUT_MAILFROM, CALLOUT_POSTMASTER_MAILFROM, CALLOUT_MAXWAIT, CALLOUT_CONNECT,
1531 CALLOUT_HOLD, CALLOUT_TIME /* TIME must be last */
1532 };
1533 typedef struct {
1534 uschar * name;
1535 int value;
1536 int flag;
1537 BOOL has_option; /* Has =option(s) following */
1538 BOOL timeval; /* Has a time value */
1539 } callout_opt_t;
1540 static callout_opt_t callout_opt_list[] = {
1541 /* name value flag has-opt has-time */
1542 { US"defer_ok", CALLOUT_DEFER_OK, 0, FALSE, FALSE },
1543 { US"no_cache", CALLOUT_NOCACHE, vopt_callout_no_cache, FALSE, FALSE },
1544 { US"random", CALLOUT_RANDOM, vopt_callout_random, FALSE, FALSE },
1545 { US"use_sender", CALLOUT_USE_SENDER, vopt_callout_recipsender, FALSE, FALSE },
1546 { US"use_postmaster", CALLOUT_USE_POSTMASTER,vopt_callout_recippmaster, FALSE, FALSE },
1547 { US"postmaster_mailfrom",CALLOUT_POSTMASTER_MAILFROM,0, TRUE, FALSE },
1548 { US"postmaster", CALLOUT_POSTMASTER, 0, FALSE, FALSE },
1549 { US"fullpostmaster", CALLOUT_FULLPOSTMASTER,vopt_callout_fullpm, FALSE, FALSE },
1550 { US"mailfrom", CALLOUT_MAILFROM, 0, TRUE, FALSE },
1551 { US"maxwait", CALLOUT_MAXWAIT, 0, TRUE, TRUE },
1552 { US"connect", CALLOUT_CONNECT, 0, TRUE, TRUE },
1553 { US"hold", CALLOUT_HOLD, vopt_callout_hold, FALSE, FALSE },
1554 { NULL, CALLOUT_TIME, 0, FALSE, TRUE }
1555 };
1556
1557
1558
1559 /* This function implements the "verify" condition. It is called when
1560 encountered in any ACL, because some tests are almost always permitted. Some
1561 just don't make sense, and always fail (for example, an attempt to test a host
1562 lookup for a non-TCP/IP message). Others are restricted to certain ACLs.
1563
1564 Arguments:
1565 where where called from
1566 addr the recipient address that the ACL is handling, or NULL
1567 arg the argument of "verify"
1568 user_msgptr pointer for user message
1569 log_msgptr pointer for log message
1570 basic_errno where to put verify errno
1571
1572 Returns: OK verification condition succeeded
1573 FAIL verification failed
1574 DEFER there was a problem verifying
1575 ERROR syntax error
1576 */
1577
1578 static int
1579 acl_verify(int where, address_item *addr, const uschar *arg,
1580 uschar **user_msgptr, uschar **log_msgptr, int *basic_errno)
1581 {
1582 int sep = '/';
1583 int callout = -1;
1584 int callout_overall = -1;
1585 int callout_connect = -1;
1586 int verify_options = 0;
1587 int rc;
1588 BOOL verify_header_sender = FALSE;
1589 BOOL defer_ok = FALSE;
1590 BOOL callout_defer_ok = FALSE;
1591 BOOL no_details = FALSE;
1592 BOOL success_on_redirect = FALSE;
1593 address_item *sender_vaddr = NULL;
1594 uschar *verify_sender_address = NULL;
1595 uschar *pm_mailfrom = NULL;
1596 uschar *se_mailfrom = NULL;
1597
1598 /* Some of the verify items have slash-separated options; some do not. Diagnose
1599 an error if options are given for items that don't expect them.
1600 */
1601
1602 uschar *slash = Ustrchr(arg, '/');
1603 const uschar *list = arg;
1604 uschar *ss = string_nextinlist(&list, &sep, big_buffer, big_buffer_size);
1605 verify_type_t * vp;
1606
1607 if (!ss) goto BAD_VERIFY;
1608
1609 /* Handle name/address consistency verification in a separate function. */
1610
1611 for (vp = verify_type_list;
1612 CS vp < CS verify_type_list + sizeof(verify_type_list);
1613 vp++
1614 )
1615 if (vp->alt_opt_sep ? strncmpic(ss, vp->name, vp->alt_opt_sep) == 0
1616 : strcmpic (ss, vp->name) == 0)
1617 break;
1618 if (CS vp >= CS verify_type_list + sizeof(verify_type_list))
1619 goto BAD_VERIFY;
1620
1621 if (vp->no_options && slash)
1622 {
1623 *log_msgptr = string_sprintf("unexpected '/' found in \"%s\" "
1624 "(this verify item has no options)", arg);
1625 return ERROR;
1626 }
1627 if (!(vp->where_allowed & BIT(where)))
1628 {
1629 *log_msgptr = string_sprintf("cannot verify %s in ACL for %s",
1630 vp->name, acl_wherenames[where]);
1631 return ERROR;
1632 }
1633 switch(vp->value)
1634 {
1635 case VERIFY_REV_HOST_LKUP:
1636 if (!sender_host_address) return OK;
1637 if ((rc = acl_verify_reverse(user_msgptr, log_msgptr)) == DEFER)
1638 while ((ss = string_nextinlist(&list, &sep, NULL, 0)))
1639 if (strcmpic(ss, US"defer_ok") == 0)
1640 return OK;
1641 return rc;
1642
1643 case VERIFY_CERT:
1644 /* TLS certificate verification is done at STARTTLS time; here we just
1645 test whether it was successful or not. (This is for optional verification; for
1646 mandatory verification, the connection doesn't last this long.) */
1647
1648 if (tls_in.certificate_verified) return OK;
1649 *user_msgptr = US"no verified certificate";
1650 return FAIL;
1651
1652 case VERIFY_HELO:
1653 /* We can test the result of optional HELO verification that might have
1654 occurred earlier. If not, we can attempt the verification now. */
1655
1656 if (!f.helo_verified && !f.helo_verify_failed) smtp_verify_helo();
1657 return f.helo_verified ? OK : FAIL;
1658
1659 case VERIFY_CSA:
1660 /* Do Client SMTP Authorization checks in a separate function, and turn the
1661 result code into user-friendly strings. */
1662
1663 rc = acl_verify_csa(list);
1664 *log_msgptr = *user_msgptr = string_sprintf("client SMTP authorization %s",
1665 csa_reason_string[rc]);
1666 csa_status = csa_status_string[rc];
1667 DEBUG(D_acl) debug_printf_indent("CSA result %s\n", csa_status);
1668 return csa_return_code[rc];
1669
1670 #ifdef EXPERIMENTAL_ARC
1671 case VERIFY_ARC:
1672 { /* Do Authenticated Received Chain checks in a separate function. */
1673 const uschar * condlist = CUS string_nextinlist(&list, &sep, NULL, 0);
1674 int csep = 0;
1675 uschar * cond;
1676
1677 if (!(arc_state = acl_verify_arc())) return DEFER;
1678 DEBUG(D_acl) debug_printf_indent("ARC verify result %s %s%s%s\n", arc_state,
1679 arc_state_reason ? "(":"", arc_state_reason, arc_state_reason ? ")":"");
1680
1681 if (!condlist) condlist = US"none:pass";
1682 while ((cond = string_nextinlist(&condlist, &csep, NULL, 0)))
1683 if (Ustrcmp(arc_state, cond) == 0) return OK;
1684 return FAIL;
1685 }
1686 #endif
1687
1688 case VERIFY_HDR_SYNTAX:
1689 /* Check that all relevant header lines have the correct 5322-syntax. If there is
1690 a syntax error, we return details of the error to the sender if configured to
1691 send out full details. (But a "message" setting on the ACL can override, as
1692 always). */
1693
1694 rc = verify_check_headers(log_msgptr);
1695 if (rc != OK && *log_msgptr)
1696 if (smtp_return_error_details)
1697 *user_msgptr = string_sprintf("Rejected after DATA: %s", *log_msgptr);
1698 else
1699 acl_verify_message = *log_msgptr;
1700 return rc;
1701
1702 case VERIFY_HDR_NAMES_ASCII:
1703 /* Check that all header names are true 7 bit strings
1704 See RFC 5322, 2.2. and RFC 6532, 3. */
1705
1706 rc = verify_check_header_names_ascii(log_msgptr);
1707 if (rc != OK && smtp_return_error_details && *log_msgptr)
1708 *user_msgptr = string_sprintf("Rejected after DATA: %s", *log_msgptr);
1709 return rc;
1710
1711 case VERIFY_NOT_BLIND:
1712 /* Check that no recipient of this message is "blind", that is, every envelope
1713 recipient must be mentioned in either To: or Cc:. */
1714 {
1715 BOOL case_sensitive = TRUE;
1716
1717 while ((ss = string_nextinlist(&list, &sep, NULL, 0)))
1718 if (strcmpic(ss, US"case_insensitive") == 0)
1719 case_sensitive = FALSE;
1720 else
1721 {
1722 *log_msgptr = string_sprintf("unknown option \"%s\" in ACL "
1723 "condition \"verify %s\"", ss, arg);
1724 return ERROR;
1725 }
1726
1727 if ((rc = verify_check_notblind(case_sensitive)) != OK)
1728 {
1729 *log_msgptr = US"bcc recipient detected";
1730 if (smtp_return_error_details)
1731 *user_msgptr = string_sprintf("Rejected after DATA: %s", *log_msgptr);
1732 }
1733 return rc;
1734 }
1735
1736 /* The remaining verification tests check recipient and sender addresses,
1737 either from the envelope or from the header. There are a number of
1738 slash-separated options that are common to all of them. */
1739
1740 case VERIFY_HDR_SNDR:
1741 verify_header_sender = TRUE;
1742 break;
1743
1744 case VERIFY_SNDR:
1745 /* In the case of a sender, this can optionally be followed by an address to use
1746 in place of the actual sender (rare special-case requirement). */
1747 {
1748 uschar *s = ss + 6;
1749 if (*s == 0)
1750 verify_sender_address = sender_address;
1751 else
1752 {
1753 while (isspace(*s)) s++;
1754 if (*s++ != '=') goto BAD_VERIFY;
1755 while (isspace(*s)) s++;
1756 verify_sender_address = string_copy(s);
1757 }
1758 }
1759 break;
1760
1761 case VERIFY_RCPT:
1762 break;
1763 }
1764
1765
1766
1767 /* Remaining items are optional; they apply to sender and recipient
1768 verification, including "header sender" verification. */
1769
1770 while ((ss = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
1771 {
1772 if (strcmpic(ss, US"defer_ok") == 0) defer_ok = TRUE;
1773 else if (strcmpic(ss, US"no_details") == 0) no_details = TRUE;
1774 else if (strcmpic(ss, US"success_on_redirect") == 0) success_on_redirect = TRUE;
1775
1776 /* These two old options are left for backwards compatibility */
1777
1778 else if (strcmpic(ss, US"callout_defer_ok") == 0)
1779 {
1780 callout_defer_ok = TRUE;
1781 if (callout == -1) callout = CALLOUT_TIMEOUT_DEFAULT;
1782 }
1783
1784 else if (strcmpic(ss, US"check_postmaster") == 0)
1785 {
1786 pm_mailfrom = US"";
1787 if (callout == -1) callout = CALLOUT_TIMEOUT_DEFAULT;
1788 }
1789
1790 /* The callout option has a number of sub-options, comma separated */
1791
1792 else if (strncmpic(ss, US"callout", 7) == 0)
1793 {
1794 callout = CALLOUT_TIMEOUT_DEFAULT;
1795 ss += 7;
1796 if (*ss != 0)
1797 {
1798 while (isspace(*ss)) ss++;
1799 if (*ss++ == '=')
1800 {
1801 const uschar * sublist = ss;
1802 int optsep = ',';
1803 uschar buffer[256];
1804 uschar * opt;
1805
1806 while (isspace(*sublist)) sublist++;
1807 while ((opt = string_nextinlist(&sublist, &optsep, buffer, sizeof(buffer))))
1808 {
1809 callout_opt_t * op;
1810 double period = 1.0F;
1811
1812 for (op= callout_opt_list; op->name; op++)
1813 if (strncmpic(opt, op->name, Ustrlen(op->name)) == 0)
1814 break;
1815
1816 verify_options |= op->flag;
1817 if (op->has_option)
1818 {
1819 opt += Ustrlen(op->name);
1820 while (isspace(*opt)) opt++;
1821 if (*opt++ != '=')
1822 {
1823 *log_msgptr = string_sprintf("'=' expected after "
1824 "\"%s\" in ACL verify condition \"%s\"", op->name, arg);
1825 return ERROR;
1826 }
1827 while (isspace(*opt)) opt++;
1828 }
1829 if (op->timeval && (period = readconf_readtime(opt, 0, FALSE)) < 0)
1830 {
1831 *log_msgptr = string_sprintf("bad time value in ACL condition "
1832 "\"verify %s\"", arg);
1833 return ERROR;
1834 }
1835
1836 switch(op->value)
1837 {
1838 case CALLOUT_DEFER_OK: callout_defer_ok = TRUE; break;
1839 case CALLOUT_POSTMASTER: pm_mailfrom = US""; break;
1840 case CALLOUT_FULLPOSTMASTER: pm_mailfrom = US""; break;
1841 case CALLOUT_MAILFROM:
1842 if (!verify_header_sender)
1843 {
1844 *log_msgptr = string_sprintf("\"mailfrom\" is allowed as a "
1845 "callout option only for verify=header_sender (detected in ACL "
1846 "condition \"%s\")", arg);
1847 return ERROR;
1848 }
1849 se_mailfrom = string_copy(opt);
1850 break;
1851 case CALLOUT_POSTMASTER_MAILFROM: pm_mailfrom = string_copy(opt); break;
1852 case CALLOUT_MAXWAIT: callout_overall = period; break;
1853 case CALLOUT_CONNECT: callout_connect = period; break;
1854 case CALLOUT_TIME: callout = period; break;
1855 }
1856 }
1857 }
1858 else
1859 {
1860 *log_msgptr = string_sprintf("'=' expected after \"callout\" in "
1861 "ACL condition \"%s\"", arg);
1862 return ERROR;
1863 }
1864 }
1865 }
1866
1867 /* Option not recognized */
1868
1869 else
1870 {
1871 *log_msgptr = string_sprintf("unknown option \"%s\" in ACL "
1872 "condition \"verify %s\"", ss, arg);
1873 return ERROR;
1874 }
1875 }
1876
1877 if ((verify_options & (vopt_callout_recipsender|vopt_callout_recippmaster)) ==
1878 (vopt_callout_recipsender|vopt_callout_recippmaster))
1879 {
1880 *log_msgptr = US"only one of use_sender and use_postmaster can be set "
1881 "for a recipient callout";
1882 return ERROR;
1883 }
1884
1885 /* Handle sender-in-header verification. Default the user message to the log
1886 message if giving out verification details. */
1887
1888 if (verify_header_sender)
1889 {
1890 int verrno;
1891
1892 if ((rc = verify_check_header_address(user_msgptr, log_msgptr, callout,
1893 callout_overall, callout_connect, se_mailfrom, pm_mailfrom, verify_options,
1894 &verrno)) != OK)
1895 {
1896 *basic_errno = verrno;
1897 if (smtp_return_error_details)
1898 {
1899 if (!*user_msgptr && *log_msgptr)
1900 *user_msgptr = string_sprintf("Rejected after DATA: %s", *log_msgptr);
1901 if (rc == DEFER) f.acl_temp_details = TRUE;
1902 }
1903 }
1904 }
1905
1906 /* Handle a sender address. The default is to verify *the* sender address, but
1907 optionally a different address can be given, for special requirements. If the
1908 address is empty, we are dealing with a bounce message that has no sender, so
1909 we cannot do any checking. If the real sender address gets rewritten during
1910 verification (e.g. DNS widening), set the flag to stop it being rewritten again
1911 during message reception.
1912
1913 A list of verified "sender" addresses is kept to try to avoid doing to much
1914 work repetitively when there are multiple recipients in a message and they all
1915 require sender verification. However, when callouts are involved, it gets too
1916 complicated because different recipients may require different callout options.
1917 Therefore, we always do a full sender verify when any kind of callout is
1918 specified. Caching elsewhere, for instance in the DNS resolver and in the
1919 callout handling, should ensure that this is not terribly inefficient. */
1920
1921 else if (verify_sender_address)
1922 {
1923 if ((verify_options & (vopt_callout_recipsender|vopt_callout_recippmaster)))
1924 {
1925 *log_msgptr = US"use_sender or use_postmaster cannot be used for a "
1926 "sender verify callout";
1927 return ERROR;
1928 }
1929
1930 sender_vaddr = verify_checked_sender(verify_sender_address);
1931 if (sender_vaddr != NULL && /* Previously checked */
1932 callout <= 0) /* No callout needed this time */
1933 {
1934 /* If the "routed" flag is set, it means that routing worked before, so
1935 this check can give OK (the saved return code value, if set, belongs to a
1936 callout that was done previously). If the "routed" flag is not set, routing
1937 must have failed, so we use the saved return code. */
1938
1939 if (testflag(sender_vaddr, af_verify_routed))
1940 rc = OK;
1941 else
1942 {
1943 rc = sender_vaddr->special_action;
1944 *basic_errno = sender_vaddr->basic_errno;
1945 }
1946 HDEBUG(D_acl) debug_printf_indent("using cached sender verify result\n");
1947 }
1948
1949 /* Do a new verification, and cache the result. The cache is used to avoid
1950 verifying the sender multiple times for multiple RCPTs when callouts are not
1951 specified (see comments above).
1952
1953 The cache is also used on failure to give details in response to the first
1954 RCPT that gets bounced for this reason. However, this can be suppressed by
1955 the no_details option, which sets the flag that says "this detail has already
1956 been sent". The cache normally contains just one address, but there may be
1957 more in esoteric circumstances. */
1958
1959 else
1960 {
1961 BOOL routed = TRUE;
1962 uschar *save_address_data = deliver_address_data;
1963
1964 sender_vaddr = deliver_make_addr(verify_sender_address, TRUE);
1965 #ifdef SUPPORT_I18N
1966 if ((sender_vaddr->prop.utf8_msg = message_smtputf8))
1967 {
1968 sender_vaddr->prop.utf8_downcvt = message_utf8_downconvert == 1;
1969 sender_vaddr->prop.utf8_downcvt_maybe = message_utf8_downconvert == -1;
1970 }
1971 #endif
1972 if (no_details) setflag(sender_vaddr, af_sverify_told);
1973 if (verify_sender_address[0] != 0)
1974 {
1975 /* If this is the real sender address, save the unrewritten version
1976 for use later in receive. Otherwise, set a flag so that rewriting the
1977 sender in verify_address() does not update sender_address. */
1978
1979 if (verify_sender_address == sender_address)
1980 sender_address_unrewritten = sender_address;
1981 else
1982 verify_options |= vopt_fake_sender;
1983
1984 if (success_on_redirect)
1985 verify_options |= vopt_success_on_redirect;
1986
1987 /* The recipient, qualify, and expn options are never set in
1988 verify_options. */
1989
1990 rc = verify_address(sender_vaddr, NULL, verify_options, callout,
1991 callout_overall, callout_connect, se_mailfrom, pm_mailfrom, &routed);
1992
1993 HDEBUG(D_acl) debug_printf_indent("----------- end verify ------------\n");
1994
1995 if (rc != OK)
1996 *basic_errno = sender_vaddr->basic_errno;
1997 else
1998 DEBUG(D_acl)
1999 {
2000 if (Ustrcmp(sender_vaddr->address, verify_sender_address) != 0)
2001 debug_printf_indent("sender %s verified ok as %s\n",
2002 verify_sender_address, sender_vaddr->address);
2003 else
2004 debug_printf_indent("sender %s verified ok\n",
2005 verify_sender_address);
2006 }
2007 }
2008 else
2009 rc = OK; /* Null sender */
2010
2011 /* Cache the result code */
2012
2013 if (routed) setflag(sender_vaddr, af_verify_routed);
2014 if (callout > 0) setflag(sender_vaddr, af_verify_callout);
2015 sender_vaddr->special_action = rc;
2016 sender_vaddr->next = sender_verified_list;
2017 sender_verified_list = sender_vaddr;
2018
2019 /* Restore the recipient address data, which might have been clobbered by
2020 the sender verification. */
2021
2022 deliver_address_data = save_address_data;
2023 }
2024
2025 /* Put the sender address_data value into $sender_address_data */
2026
2027 sender_address_data = sender_vaddr->prop.address_data;
2028 }
2029
2030 /* A recipient address just gets a straightforward verify; again we must handle
2031 the DEFER overrides. */
2032
2033 else
2034 {
2035 address_item addr2;
2036
2037 if (success_on_redirect)
2038 verify_options |= vopt_success_on_redirect;
2039
2040 /* We must use a copy of the address for verification, because it might
2041 get rewritten. */
2042
2043 addr2 = *addr;
2044 rc = verify_address(&addr2, NULL, verify_options|vopt_is_recipient, callout,
2045 callout_overall, callout_connect, se_mailfrom, pm_mailfrom, NULL);
2046 HDEBUG(D_acl) debug_printf_indent("----------- end verify ------------\n");
2047
2048 *basic_errno = addr2.basic_errno;
2049 *log_msgptr = addr2.message;
2050 *user_msgptr = (addr2.user_message != NULL)?
2051 addr2.user_message : addr2.message;
2052
2053 /* Allow details for temporary error if the address is so flagged. */
2054 if (testflag((&addr2), af_pass_message)) f.acl_temp_details = TRUE;
2055
2056 /* Make $address_data visible */
2057 deliver_address_data = addr2.prop.address_data;
2058 }
2059
2060 /* We have a result from the relevant test. Handle defer overrides first. */
2061
2062 if (rc == DEFER && (defer_ok ||
2063 (callout_defer_ok && *basic_errno == ERRNO_CALLOUTDEFER)))
2064 {
2065 HDEBUG(D_acl) debug_printf_indent("verify defer overridden by %s\n",
2066 defer_ok? "defer_ok" : "callout_defer_ok");
2067 rc = OK;
2068 }
2069
2070 /* If we've failed a sender, set up a recipient message, and point
2071 sender_verified_failed to the address item that actually failed. */
2072
2073 if (rc != OK && verify_sender_address != NULL)
2074 {
2075 if (rc != DEFER)
2076 *log_msgptr = *user_msgptr = US"Sender verify failed";
2077 else if (*basic_errno != ERRNO_CALLOUTDEFER)
2078 *log_msgptr = *user_msgptr = US"Could not complete sender verify";
2079 else
2080 {
2081 *log_msgptr = US"Could not complete sender verify callout";
2082 *user_msgptr = smtp_return_error_details? sender_vaddr->user_message :
2083 *log_msgptr;
2084 }
2085
2086 sender_verified_failed = sender_vaddr;
2087 }
2088
2089 /* Verifying an address messes up the values of $domain and $local_part,
2090 so reset them before returning if this is a RCPT ACL. */
2091
2092 if (addr != NULL)
2093 {
2094 deliver_domain = addr->domain;
2095 deliver_localpart = addr->local_part;
2096 }
2097 return rc;
2098
2099 /* Syntax errors in the verify argument come here. */
2100
2101 BAD_VERIFY:
2102 *log_msgptr = string_sprintf("expected \"sender[=address]\", \"recipient\", "
2103 "\"helo\", \"header_syntax\", \"header_sender\", \"header_names_ascii\" "
2104 "or \"reverse_host_lookup\" at start of ACL condition "
2105 "\"verify %s\"", arg);
2106 return ERROR;
2107 }
2108
2109
2110
2111
2112 /*************************************************
2113 * Check argument for control= modifier *
2114 *************************************************/
2115
2116 /* Called from acl_check_condition() below
2117
2118 Arguments:
2119 arg the argument string for control=
2120 pptr set to point to the terminating character
2121 where which ACL we are in
2122 log_msgptr for error messages
2123
2124 Returns: CONTROL_xxx value
2125 */
2126
2127 static int
2128 decode_control(const uschar *arg, const uschar **pptr, int where, uschar **log_msgptr)
2129 {
2130 int idx, len;
2131 control_def * d;
2132
2133 if ( (idx = find_control(arg, controls_list, nelem(controls_list))) < 0
2134 || ( arg[len = Ustrlen((d = controls_list+idx)->name)] != 0
2135 && (!d->has_option || arg[len] != '/')
2136 ) )
2137 {
2138 *log_msgptr = string_sprintf("syntax error in \"control=%s\"", arg);
2139 return CONTROL_ERROR;
2140 }
2141
2142 *pptr = arg + len;
2143 return idx;
2144 }
2145
2146
2147
2148
2149 /*************************************************
2150 * Return a ratelimit error *
2151 *************************************************/
2152
2153 /* Called from acl_ratelimit() below
2154
2155 Arguments:
2156 log_msgptr for error messages
2157 format format string
2158 ... supplementary arguments
2159
2160 Returns: ERROR
2161 */
2162
2163 static int
2164 ratelimit_error(uschar **log_msgptr, const char *format, ...)
2165 {
2166 va_list ap;
2167 gstring * g =
2168 string_cat(NULL, US"error in arguments to \"ratelimit\" condition: ");
2169
2170 va_start(ap, format);
2171 g = string_vformat(g, SVFMT_EXTEND|SVFMT_REBUFFER, format, ap);
2172 va_end(ap);
2173
2174 gstring_release_unused(g);
2175 *log_msgptr = string_from_gstring(g);
2176 return ERROR;
2177 }
2178
2179
2180
2181
2182 /*************************************************
2183 * Handle rate limiting *
2184 *************************************************/
2185
2186 /* Called by acl_check_condition() below to calculate the result
2187 of the ACL ratelimit condition.
2188
2189 Note that the return value might be slightly unexpected: if the
2190 sender's rate is above the limit then the result is OK. This is
2191 similar to the dnslists condition, and is so that you can write
2192 ACL clauses like: defer ratelimit = 15 / 1h
2193
2194 Arguments:
2195 arg the option string for ratelimit=
2196 where ACL_WHERE_xxxx indicating which ACL this is
2197 log_msgptr for error messages
2198
2199 Returns: OK - Sender's rate is above limit
2200 FAIL - Sender's rate is below limit
2201 DEFER - Problem opening ratelimit database
2202 ERROR - Syntax error in options.
2203 */
2204
2205 static int
2206 acl_ratelimit(const uschar *arg, int where, uschar **log_msgptr)
2207 {
2208 double limit, period, count;
2209 uschar *ss;
2210 uschar *key = NULL;
2211 uschar *unique = NULL;
2212 int sep = '/';
2213 BOOL leaky = FALSE, strict = FALSE, readonly = FALSE;
2214 BOOL noupdate = FALSE, badacl = FALSE;
2215 int mode = RATE_PER_WHAT;
2216 int old_pool, rc;
2217 tree_node **anchor, *t;
2218 open_db dbblock, *dbm;
2219 int dbdb_size;
2220 dbdata_ratelimit *dbd;
2221 dbdata_ratelimit_unique *dbdb;
2222 struct timeval tv;
2223
2224 /* Parse the first two options and record their values in expansion
2225 variables. These variables allow the configuration to have informative
2226 error messages based on rate limits obtained from a table lookup. */
2227
2228 /* First is the maximum number of messages per period / maximum burst
2229 size, which must be greater than or equal to zero. Zero is useful for
2230 rate measurement as opposed to rate limiting. */
2231
2232 if (!(sender_rate_limit = string_nextinlist(&arg, &sep, NULL, 0)))
2233 return ratelimit_error(log_msgptr, "sender rate limit not set");
2234
2235 limit = Ustrtod(sender_rate_limit, &ss);
2236 if (tolower(*ss) == 'k') { limit *= 1024.0; ss++; }
2237 else if (tolower(*ss) == 'm') { limit *= 1024.0*1024.0; ss++; }
2238 else if (tolower(*ss) == 'g') { limit *= 1024.0*1024.0*1024.0; ss++; }
2239
2240 if (limit < 0.0 || *ss != '\0')
2241 return ratelimit_error(log_msgptr,
2242 "\"%s\" is not a positive number", sender_rate_limit);
2243
2244 /* Second is the rate measurement period / exponential smoothing time
2245 constant. This must be strictly greater than zero, because zero leads to
2246 run-time division errors. */
2247
2248 period = !(sender_rate_period = string_nextinlist(&arg, &sep, NULL, 0))
2249 ? -1.0 : readconf_readtime(sender_rate_period, 0, FALSE);
2250 if (period <= 0.0)
2251 return ratelimit_error(log_msgptr,
2252 "\"%s\" is not a time value", sender_rate_period);
2253
2254 /* By default we are counting one of something, but the per_rcpt,
2255 per_byte, and count options can change this. */
2256
2257 count = 1.0;
2258
2259 /* Parse the other options. */
2260
2261 while ((ss = string_nextinlist(&arg, &sep, big_buffer, big_buffer_size)))
2262 {
2263 if (strcmpic(ss, US"leaky") == 0) leaky = TRUE;
2264 else if (strcmpic(ss, US"strict") == 0) strict = TRUE;
2265 else if (strcmpic(ss, US"noupdate") == 0) noupdate = TRUE;
2266 else if (strcmpic(ss, US"readonly") == 0) readonly = TRUE;
2267 else if (strcmpic(ss, US"per_cmd") == 0) RATE_SET(mode, PER_CMD);
2268 else if (strcmpic(ss, US"per_conn") == 0)
2269 {
2270 RATE_SET(mode, PER_CONN);
2271 if (where == ACL_WHERE_NOTSMTP || where == ACL_WHERE_NOTSMTP_START)
2272 badacl = TRUE;
2273 }
2274 else if (strcmpic(ss, US"per_mail") == 0)
2275 {
2276 RATE_SET(mode, PER_MAIL);
2277 if (where > ACL_WHERE_NOTSMTP) badacl = TRUE;
2278 }
2279 else if (strcmpic(ss, US"per_rcpt") == 0)
2280 {
2281 /* If we are running in the RCPT ACL, then we'll count the recipients
2282 one by one, but if we are running when we have accumulated the whole
2283 list then we'll add them all in one batch. */
2284 if (where == ACL_WHERE_RCPT)
2285 RATE_SET(mode, PER_RCPT);
2286 else if (where >= ACL_WHERE_PREDATA && where <= ACL_WHERE_NOTSMTP)
2287 RATE_SET(mode, PER_ALLRCPTS), count = (double)recipients_count;
2288 else if (where == ACL_WHERE_MAIL || where > ACL_WHERE_NOTSMTP)
2289 RATE_SET(mode, PER_RCPT), badacl = TRUE;
2290 }
2291 else if (strcmpic(ss, US"per_byte") == 0)
2292 {
2293 /* If we have not yet received the message data and there was no SIZE
2294 declaration on the MAIL command, then it's safe to just use a value of
2295 zero and let the recorded rate decay as if nothing happened. */
2296 RATE_SET(mode, PER_MAIL);
2297 if (where > ACL_WHERE_NOTSMTP) badacl = TRUE;
2298 else count = message_size < 0 ? 0.0 : (double)message_size;
2299 }
2300 else if (strcmpic(ss, US"per_addr") == 0)
2301 {
2302 RATE_SET(mode, PER_RCPT);
2303 if (where != ACL_WHERE_RCPT) badacl = TRUE, unique = US"*";
2304 else unique = string_sprintf("%s@%s", deliver_localpart, deliver_domain);
2305 }
2306 else if (strncmpic(ss, US"count=", 6) == 0)
2307 {
2308 uschar *e;
2309 count = Ustrtod(ss+6, &e);
2310 if (count < 0.0 || *e != '\0')
2311 return ratelimit_error(log_msgptr, "\"%s\" is not a positive number", ss);
2312 }
2313 else if (strncmpic(ss, US"unique=", 7) == 0)
2314 unique = string_copy(ss + 7);
2315 else if (!key)
2316 key = string_copy(ss);
2317 else
2318 key = string_sprintf("%s/%s", key, ss);
2319 }
2320
2321 /* Sanity check. When the badacl flag is set the update mode must either
2322 be readonly (which is the default if it is omitted) or, for backwards
2323 compatibility, a combination of noupdate and strict or leaky. */
2324
2325 if (mode == RATE_PER_CLASH)
2326 return ratelimit_error(log_msgptr, "conflicting per_* options");
2327 if (leaky + strict + readonly > 1)
2328 return ratelimit_error(log_msgptr, "conflicting update modes");
2329 if (badacl && (leaky || strict) && !noupdate)
2330 return ratelimit_error(log_msgptr,
2331 "\"%s\" must not have /leaky or /strict option, or cannot be used in %s ACL",
2332 ratelimit_option_string[mode], acl_wherenames[where]);
2333
2334 /* Set the default values of any unset options. In readonly mode we
2335 perform the rate computation without any increment so that its value
2336 decays to eventually allow over-limit senders through. */
2337
2338 if (noupdate) readonly = TRUE, leaky = strict = FALSE;
2339 if (badacl) readonly = TRUE;
2340 if (readonly) count = 0.0;
2341 if (!strict && !readonly) leaky = TRUE;
2342 if (mode == RATE_PER_WHAT) mode = RATE_PER_MAIL;
2343
2344 /* Create the lookup key. If there is no explicit key, use sender_host_address.
2345 If there is no sender_host_address (e.g. -bs or acl_not_smtp) then we simply
2346 omit it. The smoothing constant (sender_rate_period) and the per_xxx options
2347 are added to the key because they alter the meaning of the stored data. */
2348
2349 if (!key)
2350 key = !sender_host_address ? US"" : sender_host_address;
2351
2352 key = string_sprintf("%s/%s/%s%s",
2353 sender_rate_period,
2354 ratelimit_option_string[mode],
2355 unique == NULL ? "" : "unique/",
2356 key);
2357
2358 HDEBUG(D_acl)
2359 debug_printf_indent("ratelimit condition count=%.0f %.1f/%s\n", count, limit, key);
2360
2361 /* See if we have already computed the rate by looking in the relevant tree.
2362 For per-connection rate limiting, store tree nodes and dbdata in the permanent
2363 pool so that they survive across resets. In readonly mode we only remember the
2364 result for the rest of this command in case a later command changes it. After
2365 this bit of logic the code is independent of the per_* mode. */
2366
2367 old_pool = store_pool;
2368
2369 if (readonly)
2370 anchor = &ratelimiters_cmd;
2371 else switch(mode)
2372 {
2373 case RATE_PER_CONN:
2374 anchor = &ratelimiters_conn;
2375 store_pool = POOL_PERM;
2376 break;
2377 case RATE_PER_BYTE:
2378 case RATE_PER_MAIL:
2379 case RATE_PER_ALLRCPTS:
2380 anchor = &ratelimiters_mail;
2381 break;
2382 case RATE_PER_ADDR:
2383 case RATE_PER_CMD:
2384 case RATE_PER_RCPT:
2385 anchor = &ratelimiters_cmd;
2386 break;
2387 default:
2388 anchor = NULL; /* silence an "unused" complaint */
2389 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2390 "internal ACL error: unknown ratelimit mode %d", mode);
2391 break;
2392 }
2393
2394 if ((t = tree_search(*anchor, key)))
2395 {
2396 dbd = t->data.ptr;
2397 /* The following few lines duplicate some of the code below. */
2398 rc = (dbd->rate < limit)? FAIL : OK;
2399 store_pool = old_pool;
2400 sender_rate = string_sprintf("%.1f", dbd->rate);
2401 HDEBUG(D_acl)
2402 debug_printf_indent("ratelimit found pre-computed rate %s\n", sender_rate);
2403 return rc;
2404 }
2405
2406 /* We aren't using a pre-computed rate, so get a previously recorded rate
2407 from the database, which will be updated and written back if required. */
2408
2409 if (!(dbm = dbfn_open(US"ratelimit", O_RDWR, &dbblock, TRUE, TRUE)))
2410 {
2411 store_pool = old_pool;
2412 sender_rate = NULL;
2413 HDEBUG(D_acl) debug_printf_indent("ratelimit database not available\n");
2414 *log_msgptr = US"ratelimit database not available";
2415 return DEFER;
2416 }
2417 dbdb = dbfn_read_with_length(dbm, key, &dbdb_size);
2418 dbd = NULL;
2419
2420 gettimeofday(&tv, NULL);
2421
2422 if (dbdb)
2423 {
2424 /* Locate the basic ratelimit block inside the DB data. */
2425 HDEBUG(D_acl) debug_printf_indent("ratelimit found key in database\n");
2426 dbd = &dbdb->dbd;
2427
2428 /* Forget the old Bloom filter if it is too old, so that we count each
2429 repeating event once per period. We don't simply clear and re-use the old
2430 filter because we want its size to change if the limit changes. Note that
2431 we keep the dbd pointer for copying the rate into the new data block. */
2432
2433 if(unique && tv.tv_sec > dbdb->bloom_epoch + period)
2434 {
2435 HDEBUG(D_acl) debug_printf_indent("ratelimit discarding old Bloom filter\n");
2436 dbdb = NULL;
2437 }
2438
2439 /* Sanity check. */
2440
2441 if(unique && dbdb_size < sizeof(*dbdb))
2442 {
2443 HDEBUG(D_acl) debug_printf_indent("ratelimit discarding undersize Bloom filter\n");
2444 dbdb = NULL;
2445 }
2446 }
2447
2448 /* Allocate a new data block if the database lookup failed
2449 or the Bloom filter passed its age limit. */
2450
2451 if (!dbdb)
2452 {
2453 if (!unique)
2454 {
2455 /* No Bloom filter. This basic ratelimit block is initialized below. */
2456 HDEBUG(D_acl) debug_printf_indent("ratelimit creating new rate data block\n");
2457 dbdb_size = sizeof(*dbd);
2458 dbdb = store_get(dbdb_size, FALSE); /* not tainted */
2459 }
2460 else
2461 {
2462 int extra;
2463 HDEBUG(D_acl) debug_printf_indent("ratelimit creating new Bloom filter\n");
2464
2465 /* See the long comment below for an explanation of the magic number 2.
2466 The filter has a minimum size in case the rate limit is very small;
2467 this is determined by the definition of dbdata_ratelimit_unique. */
2468
2469 extra = (int)limit * 2 - sizeof(dbdb->bloom);
2470 if (extra < 0) extra = 0;
2471 dbdb_size = sizeof(*dbdb) + extra;
2472 dbdb = store_get(dbdb_size, FALSE); /* not tainted */
2473 dbdb->bloom_epoch = tv.tv_sec;
2474 dbdb->bloom_size = sizeof(dbdb->bloom) + extra;
2475 memset(dbdb->bloom, 0, dbdb->bloom_size);
2476
2477 /* Preserve any basic ratelimit data (which is our longer-term memory)
2478 by copying it from the discarded block. */
2479
2480 if (dbd)
2481 {
2482 dbdb->dbd = *dbd;
2483 dbd = &dbdb->dbd;
2484 }
2485 }
2486 }
2487
2488 /* If we are counting unique events, find out if this event is new or not.
2489 If the client repeats the event during the current period then it should be
2490 counted. We skip this code in readonly mode for efficiency, because any
2491 changes to the filter will be discarded and because count is already set to
2492 zero. */
2493
2494 if (unique && !readonly)
2495 {
2496 /* We identify unique events using a Bloom filter. (You can find my
2497 notes on Bloom filters at http://fanf.livejournal.com/81696.html)
2498 With the per_addr option, an "event" is a recipient address, though the
2499 user can use the unique option to define their own events. We only count
2500 an event if we have not seen it before.
2501
2502 We size the filter according to the rate limit, which (in leaky mode)
2503 is the limit on the population of the filter. We allow 16 bits of space
2504 per entry (see the construction code above) and we set (up to) 8 of them
2505 when inserting an element (see the loop below). The probability of a false
2506 positive (an event we have not seen before but which we fail to count) is
2507
2508 size = limit * 16
2509 numhash = 8
2510 allzero = exp(-numhash * pop / size)
2511 = exp(-0.5 * pop / limit)
2512 fpr = pow(1 - allzero, numhash)
2513
2514 For senders at the limit the fpr is 0.06% or 1 in 1700
2515 and for senders at half the limit it is 0.0006% or 1 in 170000
2516
2517 In strict mode the Bloom filter can fill up beyond the normal limit, in
2518 which case the false positive rate will rise. This means that the
2519 measured rate for very fast senders can bogusly drop off after a while.
2520
2521 At twice the limit, the fpr is 2.5% or 1 in 40
2522 At four times the limit, it is 31% or 1 in 3.2
2523
2524 It takes ln(pop/limit) periods for an over-limit burst of pop events to
2525 decay below the limit, and if this is more than one then the Bloom filter
2526 will be discarded before the decay gets that far. The false positive rate
2527 at this threshold is 9.3% or 1 in 10.7. */
2528
2529 BOOL seen;
2530 unsigned n, hash, hinc;
2531 uschar md5sum[16];
2532 md5 md5info;
2533
2534 /* Instead of using eight independent hash values, we combine two values
2535 using the formula h1 + n * h2. This does not harm the Bloom filter's
2536 performance, and means the amount of hash we need is independent of the
2537 number of bits we set in the filter. */
2538
2539 md5_start(&md5info);
2540 md5_end(&md5info, unique, Ustrlen(unique), md5sum);
2541 hash = md5sum[0] | md5sum[1] << 8 | md5sum[2] << 16 | md5sum[3] << 24;
2542 hinc = md5sum[4] | md5sum[5] << 8 | md5sum[6] << 16 | md5sum[7] << 24;
2543
2544 /* Scan the bits corresponding to this event. A zero bit means we have
2545 not seen it before. Ensure all bits are set to record this event. */
2546
2547 HDEBUG(D_acl) debug_printf_indent("ratelimit checking uniqueness of %s\n", unique);
2548
2549 seen = TRUE;
2550 for (n = 0; n < 8; n++, hash += hinc)
2551 {
2552 int bit = 1 << (hash % 8);
2553 int byte = (hash / 8) % dbdb->bloom_size;
2554 if ((dbdb->bloom[byte] & bit) == 0)
2555 {
2556 dbdb->bloom[byte] |= bit;
2557 seen = FALSE;
2558 }
2559 }
2560
2561 /* If this event has occurred before, do not count it. */
2562
2563 if (seen)
2564 {
2565 HDEBUG(D_acl) debug_printf_indent("ratelimit event found in Bloom filter\n");
2566 count = 0.0;
2567 }
2568 else
2569 HDEBUG(D_acl) debug_printf_indent("ratelimit event added to Bloom filter\n");
2570 }
2571
2572 /* If there was no previous ratelimit data block for this key, initialize
2573 the new one, otherwise update the block from the database. The initial rate
2574 is what would be computed by the code below for an infinite interval. */
2575
2576 if (!dbd)
2577 {
2578 HDEBUG(D_acl) debug_printf_indent("ratelimit initializing new key's rate data\n");
2579 dbd = &dbdb->dbd;
2580 dbd->time_stamp = tv.tv_sec;
2581 dbd->time_usec = tv.tv_usec;
2582 dbd->rate = count;
2583 }
2584 else
2585 {
2586 /* The smoothed rate is computed using an exponentially weighted moving
2587 average adjusted for variable sampling intervals. The standard EWMA for
2588 a fixed sampling interval is: f'(t) = (1 - a) * f(t) + a * f'(t - 1)
2589 where f() is the measured value and f'() is the smoothed value.
2590
2591 Old data decays out of the smoothed value exponentially, such that data n
2592 samples old is multiplied by a^n. The exponential decay time constant p
2593 is defined such that data p samples old is multiplied by 1/e, which means
2594 that a = exp(-1/p). We can maintain the same time constant for a variable
2595 sampling interval i by using a = exp(-i/p).
2596
2597 The rate we are measuring is messages per period, suitable for directly
2598 comparing with the limit. The average rate between now and the previous
2599 message is period / interval, which we feed into the EWMA as the sample.
2600
2601 It turns out that the number of messages required for the smoothed rate
2602 to reach the limit when they are sent in a burst is equal to the limit.
2603 This can be seen by analysing the value of the smoothed rate after N
2604 messages sent at even intervals. Let k = (1 - a) * p/i
2605
2606 rate_1 = (1 - a) * p/i + a * rate_0
2607 = k + a * rate_0
2608 rate_2 = k + a * rate_1
2609 = k + a * k + a^2 * rate_0
2610 rate_3 = k + a * k + a^2 * k + a^3 * rate_0
2611 rate_N = rate_0 * a^N + k * SUM(x=0..N-1)(a^x)
2612 = rate_0 * a^N + k * (1 - a^N) / (1 - a)
2613 = rate_0 * a^N + p/i * (1 - a^N)
2614
2615 When N is large, a^N -> 0 so rate_N -> p/i as desired.
2616
2617 rate_N = p/i + (rate_0 - p/i) * a^N
2618 a^N = (rate_N - p/i) / (rate_0 - p/i)
2619 N * -i/p = log((rate_N - p/i) / (rate_0 - p/i))
2620 N = p/i * log((rate_0 - p/i) / (rate_N - p/i))
2621
2622 Numerical analysis of the above equation, setting the computed rate to
2623 increase from rate_0 = 0 to rate_N = limit, shows that for large sending
2624 rates, p/i, the number of messages N = limit. So limit serves as both the
2625 maximum rate measured in messages per period, and the maximum number of
2626 messages that can be sent in a fast burst. */
2627
2628 double this_time = (double)tv.tv_sec
2629 + (double)tv.tv_usec / 1000000.0;
2630 double prev_time = (double)dbd->time_stamp
2631 + (double)dbd->time_usec / 1000000.0;
2632
2633 /* We must avoid division by zero, and deal gracefully with the clock going
2634 backwards. If we blunder ahead when time is in reverse then the computed
2635 rate will be bogus. To be safe we clamp interval to a very small number. */
2636
2637 double interval = this_time - prev_time <= 0.0 ? 1e-9
2638 : this_time - prev_time;
2639
2640 double i_over_p = interval / period;
2641 double a = exp(-i_over_p);
2642
2643 /* Combine the instantaneous rate (period / interval) with the previous rate
2644 using the smoothing factor a. In order to measure sized events, multiply the
2645 instantaneous rate by the count of bytes or recipients etc. */
2646
2647 dbd->time_stamp = tv.tv_sec;
2648 dbd->time_usec = tv.tv_usec;
2649 dbd->rate = (1 - a) * count / i_over_p + a * dbd->rate;
2650
2651 /* When events are very widely spaced the computed rate tends towards zero.
2652 Although this is accurate it turns out not to be useful for our purposes,
2653 especially when the first event after a long silence is the start of a spam
2654 run. A more useful model is that the rate for an isolated event should be the
2655 size of the event per the period size, ignoring the lack of events outside
2656 the current period and regardless of where the event falls in the period. So,
2657 if the interval was so long that the calculated rate is unhelpfully small, we
2658 re-initialize the rate. In the absence of higher-rate bursts, the condition
2659 below is true if the interval is greater than the period. */
2660
2661 if (dbd->rate < count) dbd->rate = count;
2662 }
2663
2664 /* Clients sending at the limit are considered to be over the limit.
2665 This matters for edge cases such as a limit of zero, when the client
2666 should be completely blocked. */
2667
2668 rc = dbd->rate < limit ? FAIL : OK;
2669
2670 /* Update the state if the rate is low or if we are being strict. If we
2671 are in leaky mode and the sender's rate is too high, we do not update
2672 the recorded rate in order to avoid an over-aggressive sender's retry
2673 rate preventing them from getting any email through. If readonly is set,
2674 neither leaky nor strict are set, so we do not do any updates. */
2675
2676 if ((rc == FAIL && leaky) || strict)
2677 {
2678 dbfn_write(dbm, key, dbdb, dbdb_size);
2679 HDEBUG(D_acl) debug_printf_indent("ratelimit db updated\n");
2680 }
2681 else
2682 {
2683 HDEBUG(D_acl) debug_printf_indent("ratelimit db not updated: %s\n",
2684 readonly? "readonly mode" : "over the limit, but leaky");
2685 }
2686
2687 dbfn_close(dbm);
2688
2689 /* Store the result in the tree for future reference. Take the taint status
2690 from the key for consistency even though it's unlikely we'll ever expand this. */
2691
2692 t = store_get(sizeof(tree_node) + Ustrlen(key), is_tainted(key));
2693 t->data.ptr = dbd;
2694 Ustrcpy(t->name, key);
2695 (void)tree_insertnode(anchor, t);
2696
2697 /* We create the formatted version of the sender's rate very late in
2698 order to ensure that it is done using the correct storage pool. */
2699
2700 store_pool = old_pool;
2701 sender_rate = string_sprintf("%.1f", dbd->rate);
2702
2703 HDEBUG(D_acl)
2704 debug_printf_indent("ratelimit computed rate %s\n", sender_rate);
2705
2706 return rc;
2707 }
2708
2709
2710
2711 /*************************************************
2712 * The udpsend ACL modifier *
2713 *************************************************/
2714
2715 /* Called by acl_check_condition() below.
2716
2717 Arguments:
2718 arg the option string for udpsend=
2719 log_msgptr for error messages
2720
2721 Returns: OK - Completed.
2722 DEFER - Problem with DNS lookup.
2723 ERROR - Syntax error in options.
2724 */
2725
2726 static int
2727 acl_udpsend(const uschar *arg, uschar **log_msgptr)
2728 {
2729 int sep = 0;
2730 uschar *hostname;
2731 uschar *portstr;
2732 uschar *portend;
2733 host_item *h;
2734 int portnum;
2735 int len;
2736 int r, s;
2737 uschar * errstr;
2738
2739 hostname = string_nextinlist(&arg, &sep, NULL, 0);
2740 portstr = string_nextinlist(&arg, &sep, NULL, 0);
2741
2742 if (!hostname)
2743 {
2744 *log_msgptr = US"missing destination host in \"udpsend\" modifier";
2745 return ERROR;
2746 }
2747 if (!portstr)
2748 {
2749 *log_msgptr = US"missing destination port in \"udpsend\" modifier";
2750 return ERROR;
2751 }
2752 if (!arg)
2753 {
2754 *log_msgptr = US"missing datagram payload in \"udpsend\" modifier";
2755 return ERROR;
2756 }
2757 portnum = Ustrtol(portstr, &portend, 10);
2758 if (*portend != '\0')
2759 {
2760 *log_msgptr = US"bad destination port in \"udpsend\" modifier";
2761 return ERROR;
2762 }
2763
2764 /* Make a single-item host list. */
2765 h = store_get(sizeof(host_item), FALSE);
2766 memset(h, 0, sizeof(host_item));
2767 h->name = hostname;
2768 h->port = portnum;
2769 h->mx = MX_NONE;
2770
2771 if (string_is_ip_address(hostname, NULL))
2772 h->address = hostname, r = HOST_FOUND;
2773 else
2774 r = host_find_byname(h, NULL, 0, NULL, FALSE);
2775 if (r == HOST_FIND_FAILED || r == HOST_FIND_AGAIN)
2776 {
2777 *log_msgptr = US"DNS lookup failed in \"udpsend\" modifier";
2778 return DEFER;
2779 }
2780
2781 HDEBUG(D_acl)
2782 debug_printf_indent("udpsend [%s]:%d %s\n", h->address, portnum, arg);
2783
2784 /*XXX this could better use sendto */
2785 r = s = ip_connectedsocket(SOCK_DGRAM, h->address, portnum, portnum,
2786 1, NULL, &errstr, NULL);
2787 if (r < 0) goto defer;
2788 len = Ustrlen(arg);
2789 r = send(s, arg, len, 0);
2790 if (r < 0)
2791 {
2792 errstr = US strerror(errno);
2793 close(s);
2794 goto defer;
2795 }
2796 close(s);
2797 if (r < len)
2798 {
2799 *log_msgptr =
2800 string_sprintf("\"udpsend\" truncated from %d to %d octets", len, r);
2801 return DEFER;
2802 }
2803
2804 HDEBUG(D_acl)
2805 debug_printf_indent("udpsend %d bytes\n", r);
2806
2807 return OK;
2808
2809 defer:
2810 *log_msgptr = string_sprintf("\"udpsend\" failed: %s", errstr);
2811 return DEFER;
2812 }
2813
2814
2815
2816 /*************************************************
2817 * Handle conditions/modifiers on an ACL item *
2818 *************************************************/
2819
2820 /* Called from acl_check() below.
2821
2822 Arguments:
2823 verb ACL verb
2824 cb ACL condition block - if NULL, result is OK
2825 where where called from
2826 addr the address being checked for RCPT, or NULL
2827 level the nesting level
2828 epp pointer to pass back TRUE if "endpass" encountered
2829 (applies only to "accept" and "discard")
2830 user_msgptr user message pointer
2831 log_msgptr log message pointer
2832 basic_errno pointer to where to put verify error
2833
2834 Returns: OK - all conditions are met
2835 DISCARD - an "acl" condition returned DISCARD - only allowed
2836 for "accept" or "discard" verbs
2837 FAIL - at least one condition fails
2838 FAIL_DROP - an "acl" condition returned FAIL_DROP
2839 DEFER - can't tell at the moment (typically, lookup defer,
2840 but can be temporary callout problem)
2841 ERROR - ERROR from nested ACL or expansion failure or other
2842 error
2843 */
2844
2845 static int
2846 acl_check_condition(int verb, acl_condition_block *cb, int where,
2847 address_item *addr, int level, BOOL *epp, uschar **user_msgptr,
2848 uschar **log_msgptr, int *basic_errno)
2849 {
2850 uschar *user_message = NULL;
2851 uschar *log_message = NULL;
2852 int rc = OK;
2853 #ifdef WITH_CONTENT_SCAN
2854 int sep = -'/';
2855 #endif
2856
2857 for (; cb; cb = cb->next)
2858 {
2859 const uschar *arg;
2860 int control_type;
2861
2862 /* The message and log_message items set up messages to be used in
2863 case of rejection. They are expanded later. */
2864
2865 if (cb->type == ACLC_MESSAGE)
2866 {
2867 HDEBUG(D_acl) debug_printf_indent(" message: %s\n", cb->arg);
2868 user_message = cb->arg;
2869 continue;
2870 }
2871
2872 if (cb->type == ACLC_LOG_MESSAGE)
2873 {
2874 HDEBUG(D_acl) debug_printf_indent("l_message: %s\n", cb->arg);
2875 log_message = cb->arg;
2876 continue;
2877 }
2878
2879 /* The endpass "condition" just sets a flag to show it occurred. This is
2880 checked at compile time to be on an "accept" or "discard" item. */
2881
2882 if (cb->type == ACLC_ENDPASS)
2883 {
2884 *epp = TRUE;
2885 continue;
2886 }
2887
2888 /* For other conditions and modifiers, the argument is expanded now for some
2889 of them, but not for all, because expansion happens down in some lower level
2890 checking functions in some cases. */
2891
2892 if (!conditions[cb->type].expand_at_top)
2893 arg = cb->arg;
2894 else if (!(arg = expand_string(cb->arg)))
2895 {
2896 if (f.expand_string_forcedfail) continue;
2897 *log_msgptr = string_sprintf("failed to expand ACL string \"%s\": %s",
2898 cb->arg, expand_string_message);
2899 return f.search_find_defer ? DEFER : ERROR;
2900 }
2901
2902 /* Show condition, and expanded condition if it's different */
2903
2904 HDEBUG(D_acl)
2905 {
2906 int lhswidth = 0;
2907 debug_printf_indent("check %s%s %n",
2908 (!conditions[cb->type].is_modifier && cb->u.negated)? "!":"",
2909 conditions[cb->type].name, &lhswidth);
2910
2911 if (cb->type == ACLC_SET)
2912 {
2913 #ifndef DISABLE_DKIM
2914 if ( Ustrcmp(cb->u.varname, "dkim_verify_status") == 0
2915 || Ustrcmp(cb->u.varname, "dkim_verify_reason") == 0)
2916 {
2917 debug_printf("%s ", cb->u.varname);
2918 lhswidth += 19;
2919 }
2920 else
2921 #endif
2922 {
2923 debug_printf("acl_%s ", cb->u.varname);
2924 lhswidth += 5 + Ustrlen(cb->u.varname);
2925 }
2926 }
2927
2928 debug_printf("= %s\n", cb->arg);
2929
2930 if (arg != cb->arg)
2931 debug_printf("%.*s= %s\n", lhswidth,
2932 US" ", CS arg);
2933 }
2934
2935 /* Check that this condition makes sense at this time */
2936
2937 if ((conditions[cb->type].forbids & (1 << where)) != 0)
2938 {
2939 *log_msgptr = string_sprintf("cannot %s %s condition in %s ACL",
2940 conditions[cb->type].is_modifier ? "use" : "test",
2941 conditions[cb->type].name, acl_wherenames[where]);
2942 return ERROR;
2943 }
2944
2945 /* Run the appropriate test for each condition, or take the appropriate
2946 action for the remaining modifiers. */
2947
2948 switch(cb->type)
2949 {
2950 case ACLC_ADD_HEADER:
2951 setup_header(arg);
2952 break;
2953
2954 /* A nested ACL that returns "discard" makes sense only for an "accept" or
2955 "discard" verb. */
2956
2957 case ACLC_ACL:
2958 rc = acl_check_wargs(where, addr, arg, user_msgptr, log_msgptr);
2959 if (rc == DISCARD && verb != ACL_ACCEPT && verb != ACL_DISCARD)
2960 {
2961 *log_msgptr = string_sprintf("nested ACL returned \"discard\" for "
2962 "\"%s\" command (only allowed with \"accept\" or \"discard\")",
2963 verbs[verb]);
2964 return ERROR;
2965 }
2966 break;
2967
2968 case ACLC_AUTHENTICATED:
2969 rc = sender_host_authenticated ? match_isinlist(sender_host_authenticated,
2970 &arg, 0, NULL, NULL, MCL_STRING, TRUE, NULL) : FAIL;
2971 break;
2972
2973 #ifdef EXPERIMENTAL_BRIGHTMAIL
2974 case ACLC_BMI_OPTIN:
2975 {
2976 int old_pool = store_pool;
2977 store_pool = POOL_PERM;
2978 bmi_current_optin = string_copy(arg);
2979 store_pool = old_pool;
2980 }
2981 break;
2982 #endif
2983
2984 case ACLC_CONDITION:
2985 /* The true/false parsing here should be kept in sync with that used in
2986 expand.c when dealing with ECOND_BOOL so that we don't have too many
2987 different definitions of what can be a boolean. */
2988 if (*arg == '-'
2989 ? Ustrspn(arg+1, "0123456789") == Ustrlen(arg+1) /* Negative number */
2990 : Ustrspn(arg, "0123456789") == Ustrlen(arg)) /* Digits, or empty */
2991 rc = (Uatoi(arg) == 0)? FAIL : OK;
2992 else
2993 rc = (strcmpic(arg, US"no") == 0 ||
2994 strcmpic(arg, US"false") == 0)? FAIL :
2995 (strcmpic(arg, US"yes") == 0 ||
2996 strcmpic(arg, US"true") == 0)? OK : DEFER;
2997 if (rc == DEFER)
2998 *log_msgptr = string_sprintf("invalid \"condition\" value \"%s\"", arg);
2999 break;
3000
3001 case ACLC_CONTINUE: /* Always succeeds */
3002 break;
3003
3004 case ACLC_CONTROL:
3005 {
3006 const uschar *p = NULL;
3007 control_type = decode_control(arg, &p, where, log_msgptr);
3008
3009 /* Check if this control makes sense at this time */
3010
3011 if (controls_list[control_type].forbids & (1 << where))
3012 {
3013 *log_msgptr = string_sprintf("cannot use \"control=%s\" in %s ACL",
3014 controls_list[control_type].name, acl_wherenames[where]);
3015 return ERROR;
3016 }
3017
3018 switch(control_type)
3019 {
3020 case CONTROL_AUTH_UNADVERTISED:
3021 f.allow_auth_unadvertised = TRUE;
3022 break;
3023
3024 #ifdef EXPERIMENTAL_BRIGHTMAIL
3025 case CONTROL_BMI_RUN:
3026 bmi_run = 1;
3027 break;
3028 #endif
3029
3030 #ifndef DISABLE_DKIM
3031 case CONTROL_DKIM_VERIFY:
3032 f.dkim_disable_verify = TRUE;
3033 # ifdef SUPPORT_DMARC
3034 /* Since DKIM was blocked, skip DMARC too */
3035 f.dmarc_disable_verify = TRUE;
3036 f.dmarc_enable_forensic = FALSE;
3037 # endif
3038 break;
3039 #endif
3040
3041 #ifdef SUPPORT_DMARC
3042 case CONTROL_DMARC_VERIFY:
3043 f.dmarc_disable_verify = TRUE;
3044 break;
3045
3046 case CONTROL_DMARC_FORENSIC:
3047 f.dmarc_enable_forensic = TRUE;
3048 break;
3049 #endif
3050
3051 case CONTROL_DSCP:
3052 if (*p == '/')
3053 {
3054 int fd, af, level, optname, value;
3055 /* If we are acting on stdin, the setsockopt may fail if stdin is not
3056 a socket; we can accept that, we'll just debug-log failures anyway. */
3057 fd = fileno(smtp_in);
3058 if ((af = ip_get_address_family(fd)) < 0)
3059 {
3060 HDEBUG(D_acl)
3061 debug_printf_indent("smtp input is probably not a socket [%s], not setting DSCP\n",
3062 strerror(errno));
3063 break;
3064 }
3065 if (dscp_lookup(p+1, af, &level, &optname, &value))
3066 if (setsockopt(fd, level, optname, &value, sizeof(value)) < 0)
3067 {
3068 HDEBUG(D_acl) debug_printf_indent("failed to set input DSCP[%s]: %s\n",
3069 p+1, strerror(errno));
3070 }
3071 else
3072 {
3073 HDEBUG(D_acl) debug_printf_indent("set input DSCP to \"%s\"\n", p+1);
3074 }
3075 else
3076 {
3077 *log_msgptr = string_sprintf("unrecognised DSCP value in \"control=%s\"", arg);
3078 return ERROR;
3079 }
3080 }
3081 else
3082 {
3083 *log_msgptr = string_sprintf("syntax error in \"control=%s\"", arg);
3084 return ERROR;
3085 }
3086 break;
3087
3088 case CONTROL_ERROR:
3089 return ERROR;
3090
3091 case CONTROL_CASEFUL_LOCAL_PART:
3092 deliver_localpart = addr->cc_local_part;
3093 break;
3094
3095 case CONTROL_CASELOWER_LOCAL_PART:
3096 deliver_localpart = addr->lc_local_part;
3097 break;
3098
3099 case CONTROL_ENFORCE_SYNC:
3100 smtp_enforce_sync = TRUE;
3101 break;
3102
3103 case CONTROL_NO_ENFORCE_SYNC:
3104 smtp_enforce_sync = FALSE;
3105 break;
3106
3107 #ifdef WITH_CONTENT_SCAN
3108 case CONTROL_NO_MBOX_UNSPOOL:
3109 f.no_mbox_unspool = TRUE;
3110 break;
3111 #endif
3112
3113 case CONTROL_NO_MULTILINE:
3114 f.no_multiline_responses = TRUE;
3115 break;
3116
3117 case CONTROL_NO_PIPELINING:
3118 f.pipelining_enable = FALSE;
3119 break;
3120
3121 case CONTROL_NO_DELAY_FLUSH:
3122 f.disable_delay_flush = TRUE;
3123 break;
3124
3125 case CONTROL_NO_CALLOUT_FLUSH:
3126 f.disable_callout_flush = TRUE;
3127 break;
3128
3129 case CONTROL_FAKEREJECT:
3130 cancel_cutthrough_connection(TRUE, US"fakereject");
3131 case CONTROL_FAKEDEFER:
3132 fake_response = (control_type == CONTROL_FAKEDEFER) ? DEFER : FAIL;
3133 if (*p == '/')
3134 {
3135 const uschar *pp = p + 1;
3136 while (*pp) pp++;
3137 fake_response_text = expand_string(string_copyn(p+1, pp-p-1));
3138 p = pp;
3139 }
3140 else /* Explicitly reset to default string */
3141 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).";
3142 break;
3143
3144 case CONTROL_FREEZE:
3145 f.deliver_freeze = TRUE;
3146 deliver_frozen_at = time(NULL);
3147 freeze_tell = freeze_tell_config; /* Reset to configured value */
3148 if (Ustrncmp(p, "/no_tell", 8) == 0)
3149 {
3150 p += 8;
3151 freeze_tell = NULL;
3152 }
3153 if (*p)
3154 {
3155 *log_msgptr = string_sprintf("syntax error in \"control=%s\"", arg);
3156 return ERROR;
3157 }
3158 cancel_cutthrough_connection(TRUE, US"item frozen");
3159 break;
3160
3161 case CONTROL_QUEUE_ONLY:
3162 f.queue_only_policy = TRUE;
3163 cancel_cutthrough_connection(TRUE, US"queueing forced");
3164 break;
3165
3166 case CONTROL_SUBMISSION:
3167 originator_name = US"";
3168 f.submission_mode = TRUE;
3169 while (*p == '/')
3170 {
3171 if (Ustrncmp(p, "/sender_retain", 14) == 0)
3172 {
3173 p += 14;
3174 f.active_local_sender_retain = TRUE;
3175 f.active_local_from_check = FALSE;
3176 }
3177 else if (Ustrncmp(p, "/domain=", 8) == 0)
3178 {
3179 const uschar *pp = p + 8;
3180 while (*pp && *pp != '/') pp++;
3181 submission_domain = string_copyn(p+8, pp-p-8);
3182 p = pp;
3183 }
3184 /* The name= option must be last, because it swallows the rest of
3185 the string. */
3186 else if (Ustrncmp(p, "/name=", 6) == 0)
3187 {
3188 const uschar *pp = p + 6;
3189 while (*pp) pp++;
3190 submission_name = string_copy(parse_fix_phrase(p+6, pp-p-6,
3191 big_buffer, big_buffer_size));
3192 p = pp;
3193 }
3194 else break;
3195 }
3196 if (*p)
3197 {
3198 *log_msgptr = string_sprintf("syntax error in \"control=%s\"", arg);
3199 return ERROR;
3200 }
3201 break;
3202
3203 case CONTROL_DEBUG:
3204 {
3205 uschar * debug_tag = NULL;
3206 uschar * debug_opts = NULL;
3207 BOOL kill = FALSE;
3208
3209 while (*p == '/')
3210 {
3211 const uschar * pp = p+1;
3212 if (Ustrncmp(pp, "tag=", 4) == 0)
3213 {
3214 for (pp += 4; *pp && *pp != '/';) pp++;
3215 debug_tag = string_copyn(p+5, pp-p-5);
3216 }
3217 else if (Ustrncmp(pp, "opts=", 5) == 0)
3218 {
3219 for (pp += 5; *pp && *pp != '/';) pp++;
3220 debug_opts = string_copyn(p+6, pp-p-6);
3221 }
3222 else if (Ustrncmp(pp, "kill", 4) == 0)
3223 {
3224 for (pp += 4; *pp && *pp != '/';) pp++;
3225 kill = TRUE;
3226 }
3227 else
3228 while (*pp && *pp != '/') pp++;
3229 p = pp;
3230 }
3231
3232 if (kill)
3233 debug_logging_stop();
3234 else
3235 debug_logging_activate(debug_tag, debug_opts);
3236 break;
3237 }
3238
3239 case CONTROL_SUPPRESS_LOCAL_FIXUPS:
3240 f.suppress_local_fixups = TRUE;
3241 break;
3242
3243 case CONTROL_CUTTHROUGH_DELIVERY:
3244 {
3245 uschar * ignored = NULL;
3246 #ifndef DISABLE_PRDR
3247 if (prdr_requested)
3248 #else
3249 if (0)
3250 #endif
3251 /* Too hard to think about for now. We might in future cutthrough
3252 the case where both sides handle prdr and this-node prdr acl
3253 is "accept" */
3254 ignored = US"PRDR active";
3255 else
3256 {
3257 if (f.deliver_freeze)
3258 ignored = US"frozen";
3259 else if (f.queue_only_policy)
3260 ignored = US"queue-only";
3261 else if (fake_response == FAIL)
3262 ignored = US"fakereject";
3263 else
3264 {
3265 if (rcpt_count == 1)
3266 {
3267 cutthrough.delivery = TRUE; /* control accepted */
3268 while (*p == '/')
3269 {
3270 const uschar * pp = p+1;
3271 if (Ustrncmp(pp, "defer=", 6) == 0)
3272 {
3273 pp += 6;
3274 if (Ustrncmp(pp, "pass", 4) == 0) cutthrough.defer_pass = TRUE;
3275 /* else if (Ustrncmp(pp, "spool") == 0) ; default */
3276 }
3277 else
3278 while (*pp && *pp != '/') pp++;
3279 p = pp;
3280 }
3281 }
3282 else
3283 ignored = US"nonfirst rcpt";
3284 }
3285 }
3286 DEBUG(D_acl) if (ignored)
3287 debug_printf(" cutthrough request ignored on %s item\n", ignored);
3288 }
3289 break;
3290
3291 #ifdef SUPPORT_I18N
3292 case CONTROL_UTF8_DOWNCONVERT:
3293 if (*p == '/')
3294 {
3295 if (p[1] == '1')
3296 {
3297 message_utf8_downconvert = 1;
3298 addr->prop.utf8_downcvt = TRUE;
3299 addr->prop.utf8_downcvt_maybe = FALSE;
3300 p += 2;
3301 break;
3302 }
3303 if (p[1] == '0')
3304 {
3305 message_utf8_downconvert = 0;
3306 addr->prop.utf8_downcvt = FALSE;
3307 addr->prop.utf8_downcvt_maybe = FALSE;
3308 p += 2;
3309 break;
3310 }
3311 if (p[1] == '-' && p[2] == '1')
3312 {
3313 message_utf8_downconvert = -1;
3314 addr->prop.utf8_downcvt = FALSE;
3315 addr->prop.utf8_downcvt_maybe = TRUE;
3316 p += 3;
3317 break;
3318 }
3319 *log_msgptr = US"bad option value for control=utf8_downconvert";
3320 }
3321 else
3322 {
3323 message_utf8_downconvert = 1;
3324 addr->prop.utf8_downcvt = TRUE;
3325 addr->prop.utf8_downcvt_maybe = FALSE;
3326 break;
3327 }
3328 return ERROR;
3329 #endif
3330
3331 }
3332 break;
3333 }
3334
3335 #ifdef EXPERIMENTAL_DCC
3336 case ACLC_DCC:
3337 {
3338 /* Separate the regular expression and any optional parameters. */
3339 const uschar * list = arg;
3340 uschar *ss = string_nextinlist(&list, &sep, big_buffer, big_buffer_size);
3341 /* Run the dcc backend. */
3342 rc = dcc_process(&ss);
3343 /* Modify return code based upon the existence of options. */
3344 while ((ss = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
3345 if (strcmpic(ss, US"defer_ok") == 0 && rc == DEFER)
3346 rc = FAIL; /* FAIL so that the message is passed to the next ACL */
3347 }
3348 break;
3349 #endif
3350
3351 #ifdef WITH_CONTENT_SCAN
3352 case ACLC_DECODE:
3353 rc = mime_decode(&arg);
3354 break;
3355 #endif
3356
3357 case ACLC_DELAY:
3358 {
3359 int delay = readconf_readtime(arg, 0, FALSE);
3360 if (delay < 0)
3361 {
3362 *log_msgptr = string_sprintf("syntax error in argument for \"delay\" "
3363 "modifier: \"%s\" is not a time value", arg);
3364 return ERROR;
3365 }
3366 else
3367 {
3368 HDEBUG(D_acl) debug_printf_indent("delay modifier requests %d-second delay\n",
3369 delay);
3370 if (host_checking)
3371 {
3372 HDEBUG(D_acl)
3373 debug_printf_indent("delay skipped in -bh checking mode\n");
3374 }
3375
3376 /* NOTE 1: Remember that we may be
3377 dealing with stdin/stdout here, in addition to TCP/IP connections.
3378 Also, delays may be specified for non-SMTP input, where smtp_out and
3379 smtp_in will be NULL. Whatever is done must work in all cases.
3380
3381 NOTE 2: The added feature of flushing the output before a delay must
3382 apply only to SMTP input. Hence the test for smtp_out being non-NULL.
3383 */
3384
3385 else
3386 {
3387 if (smtp_out && !f.disable_delay_flush)
3388 mac_smtp_fflush();
3389
3390 #if !defined(NO_POLL_H) && defined (POLLRDHUP)
3391 {
3392 struct pollfd p;
3393 nfds_t n = 0;
3394 if (smtp_out)
3395 {
3396 p.fd = fileno(smtp_out);
3397 p.events = POLLRDHUP;
3398 n = 1;
3399 }
3400 if (poll(&p, n, delay*1000) > 0)
3401 HDEBUG(D_acl) debug_printf_indent("delay cancelled by peer close\n");
3402 }
3403 #else
3404 /* Lacking POLLRDHUP it appears to be impossible to detect that a
3405 TCP/IP connection has gone away without reading from it. This means
3406 that we cannot shorten the delay below if the client goes away,
3407 because we cannot discover that the client has closed its end of the
3408 connection. (The connection is actually in a half-closed state,
3409 waiting for the server to close its end.) It would be nice to be able
3410 to detect this state, so that the Exim process is not held up
3411 unnecessarily. However, it seems that we can't. The poll() function
3412 does not do the right thing, and in any case it is not always
3413 available. */
3414
3415 while (delay > 0) delay = sleep(delay);
3416 #endif
3417 }
3418 }
3419 }
3420 break;
3421
3422 #ifndef DISABLE_DKIM
3423 case ACLC_DKIM_SIGNER:
3424 if (dkim_cur_signer)
3425 rc = match_isinlist(dkim_cur_signer,
3426 &arg,0,NULL,NULL,MCL_STRING,TRUE,NULL);
3427 else
3428 rc = FAIL;
3429 break;
3430
3431 case ACLC_DKIM_STATUS:
3432 rc = match_isinlist(dkim_verify_status,
3433 &arg,0,NULL,NULL,MCL_STRING,TRUE,NULL);
3434 break;
3435 #endif
3436
3437 #ifdef SUPPORT_DMARC
3438 case ACLC_DMARC_STATUS:
3439 if (!f.dmarc_has_been_checked)
3440 dmarc_process();
3441 f.dmarc_has_been_checked = TRUE;
3442 /* used long way of dmarc_exim_expand_query() in case we need more
3443 * view into the process in the future. */
3444 rc = match_isinlist(dmarc_exim_expand_query(DMARC_VERIFY_STATUS),
3445 &arg,0,NULL,NULL,MCL_STRING,TRUE,NULL);
3446 break;
3447 #endif
3448
3449 case ACLC_DNSLISTS:
3450 rc = verify_check_dnsbl(where, &arg, log_msgptr);
3451 break;
3452
3453 case ACLC_DOMAINS:
3454 rc = match_isinlist(addr->domain, &arg, 0, &domainlist_anchor,
3455 addr->domain_cache, MCL_DOMAIN, TRUE, CUSS &deliver_domain_data);
3456 break;
3457
3458 /* The value in tls_cipher is the full cipher name, for example,
3459 TLSv1:DES-CBC3-SHA:168, whereas the values to test for are just the
3460 cipher names such as DES-CBC3-SHA. But program defensively. We don't know
3461 what may in practice come out of the SSL library - which at the time of
3462 writing is poorly documented. */
3463
3464 case ACLC_ENCRYPTED:
3465 if (tls_in.cipher == NULL) rc = FAIL; else
3466 {
3467 uschar *endcipher = NULL;
3468 uschar *cipher = Ustrchr(tls_in.cipher, ':');
3469 if (cipher == NULL) cipher = tls_in.cipher; else
3470 {
3471 endcipher = Ustrchr(++cipher, ':');
3472 if (endcipher != NULL) *endcipher = 0;
3473 }
3474 rc = match_isinlist(cipher, &arg, 0, NULL, NULL, MCL_STRING, TRUE, NULL);
3475 if (endcipher != NULL) *endcipher = ':';
3476 }
3477 break;
3478
3479 /* Use verify_check_this_host() instead of verify_check_host() so that
3480 we can pass over &host_data to catch any looked up data. Once it has been
3481 set, it retains its value so that it's still there if another ACL verb
3482 comes through here and uses the cache. However, we must put it into
3483 permanent store in case it is also expected to be used in a subsequent
3484 message in the same SMTP connection. */
3485
3486 case ACLC_HOSTS:
3487 rc = verify_check_this_host(&arg, sender_host_cache, NULL,
3488 (sender_host_address == NULL)? US"" : sender_host_address,
3489 CUSS &host_data);
3490 if (rc == DEFER) *log_msgptr = search_error_message;
3491 if (host_data) host_data = string_copy_perm(host_data, TRUE);
3492 break;
3493
3494 case ACLC_LOCAL_PARTS:
3495 rc = match_isinlist(addr->cc_local_part, &arg, 0,
3496 &localpartlist_anchor, addr->localpart_cache, MCL_LOCALPART, TRUE,
3497 CUSS &deliver_localpart_data);
3498 break;
3499
3500 case ACLC_LOG_REJECT_TARGET:
3501 {
3502 int logbits = 0;
3503 int sep = 0;
3504 const uschar *s = arg;
3505 uschar * ss;
3506 while ((ss = string_nextinlist(&s, &sep, big_buffer, big_buffer_size)))
3507 {
3508 if (Ustrcmp(ss, "main") == 0) logbits |= LOG_MAIN;
3509 else if (Ustrcmp(ss, "panic") == 0) logbits |= LOG_PANIC;
3510 else if (Ustrcmp(ss, "reject") == 0) logbits |= LOG_REJECT;
3511 else
3512 {
3513 logbits |= LOG_MAIN|LOG_REJECT;
3514 log_write(0, LOG_MAIN|LOG_PANIC, "unknown log name \"%s\" in "
3515 "\"log_reject_target\" in %s ACL", ss, acl_wherenames[where]);
3516 }
3517 }
3518 log_reject_target = logbits;
3519 }
3520 break;
3521
3522 case ACLC_LOGWRITE:
3523 {
3524 int logbits = 0;
3525 const uschar *s = arg;
3526 if (*s == ':')
3527 {
3528 s++;
3529 while (*s != ':')
3530 {
3531 if (Ustrncmp(s, "main", 4) == 0)
3532 { logbits |= LOG_MAIN; s += 4; }
3533 else if (Ustrncmp(s, "panic", 5) == 0)
3534 { logbits |= LOG_PANIC; s += 5; }
3535 else if (Ustrncmp(s, "reject", 6) == 0)
3536 { logbits |= LOG_REJECT; s += 6; }
3537 else
3538 {
3539 logbits = LOG_MAIN|LOG_PANIC;
3540 s = string_sprintf(":unknown log name in \"%s\" in "
3541 "\"logwrite\" in %s ACL", arg, acl_wherenames[where]);
3542 }
3543 if (*s == ',') s++;
3544 }
3545 s++;
3546 }
3547 while (isspace(*s)) s++;
3548
3549 if (logbits == 0) logbits = LOG_MAIN;
3550 log_write(0, logbits, "%s", string_printing(s));
3551 }
3552 break;
3553
3554 #ifdef WITH_CONTENT_SCAN
3555 case ACLC_MALWARE: /* Run the malware backend. */
3556 {
3557 /* Separate the regular expression and any optional parameters. */
3558 const uschar * list = arg;
3559 uschar * ss = string_nextinlist(&list, &sep, big_buffer, big_buffer_size);
3560 uschar * opt;
3561 BOOL defer_ok = FALSE;
3562 int timeout = 0;
3563
3564 while ((opt = string_nextinlist(&list, &sep, NULL, 0)))
3565 if (strcmpic(opt, US"defer_ok") == 0)
3566 defer_ok = TRUE;
3567 else if ( strncmpic(opt, US"tmo=", 4) == 0
3568 && (timeout = readconf_readtime(opt+4, '\0', FALSE)) < 0
3569 )
3570 {
3571 *log_msgptr = string_sprintf("bad timeout value in '%s'", opt);
3572 return ERROR;
3573 }
3574
3575 rc = malware(ss, timeout);
3576 if (rc == DEFER && defer_ok)
3577 rc = FAIL; /* FAIL so that the message is passed to the next ACL */
3578 }
3579 break;
3580
3581 case ACLC_MIME_REGEX:
3582 rc = mime_regex(&arg);
3583 break;
3584 #endif
3585
3586 case ACLC_QUEUE:
3587 if (is_tainted(arg))
3588 {
3589 *log_msgptr = string_sprintf("Tainted name '%s' for queue not permitted",
3590 arg);
3591 return ERROR;
3592 }
3593 if (Ustrchr(arg, '/'))
3594 {
3595 *log_msgptr = string_sprintf(
3596 "Directory separator not permitted in queue name: '%s'", arg);
3597 return ERROR;
3598 }
3599 queue_name = string_copy_perm(arg, FALSE);
3600 break;
3601
3602 case ACLC_RATELIMIT:
3603 rc = acl_ratelimit(arg, where, log_msgptr);
3604 break;
3605
3606 case ACLC_RECIPIENTS:
3607 rc = match_address_list(CUS addr->address, TRUE, TRUE, &arg, NULL, -1, 0,
3608 CUSS &recipient_data);
3609 break;
3610
3611 #ifdef WITH_CONTENT_SCAN
3612 case ACLC_REGEX:
3613 rc = regex(&arg);
3614 break;
3615 #endif
3616
3617 case ACLC_REMOVE_HEADER:
3618 setup_remove_header(arg);
3619 break;
3620
3621 case ACLC_SENDER_DOMAINS:
3622 {
3623 uschar *sdomain;
3624 sdomain = Ustrrchr(sender_address, '@');
3625 sdomain = sdomain ? sdomain + 1 : US"";
3626 rc = match_isinlist(sdomain, &arg, 0, &domainlist_anchor,
3627 sender_domain_cache, MCL_DOMAIN, TRUE, NULL);
3628 }
3629 break;
3630
3631 case ACLC_SENDERS:
3632 rc = match_address_list(CUS sender_address, TRUE, TRUE, &arg,
3633 sender_address_cache, -1, 0, CUSS &sender_data);
3634 break;
3635
3636 /* Connection variables must persist forever; message variables not */
3637
3638 case ACLC_SET:
3639 {
3640 int old_pool = store_pool;
3641 if ( cb->u.varname[0] != 'm'
3642 #ifndef DISABLE_EVENT
3643 || event_name /* An event is being delivered */
3644 #endif
3645 )
3646 store_pool = POOL_PERM;
3647 #ifndef DISABLE_DKIM /* Overwriteable dkim result variables */
3648 if (Ustrcmp(cb->u.varname, "dkim_verify_status") == 0)
3649 dkim_verify_status = string_copy(arg);
3650 else if (Ustrcmp(cb->u.varname, "dkim_verify_reason") == 0)
3651 dkim_verify_reason = string_copy(arg);
3652 else
3653 #endif
3654 acl_var_create(cb->u.varname)->data.ptr = string_copy(arg);
3655 store_pool = old_pool;
3656 }
3657 break;
3658
3659 #ifdef WITH_CONTENT_SCAN
3660 case ACLC_SPAM:
3661 {
3662 /* Separate the regular expression and any optional parameters. */
3663 const uschar * list = arg;
3664 uschar *ss = string_nextinlist(&list, &sep, big_buffer, big_buffer_size);
3665
3666 rc = spam(CUSS &ss);
3667 /* Modify return code based upon the existence of options. */
3668 while ((ss = string_nextinlist(&list, &sep, big_buffer, big_buffer_size)))
3669 if (strcmpic(ss, US"defer_ok") == 0 && rc == DEFER)
3670 rc = FAIL; /* FAIL so that the message is passed to the next ACL */
3671 }
3672 break;
3673 #endif
3674
3675 #ifdef SUPPORT_SPF
3676 case ACLC_SPF:
3677 rc = spf_process(&arg, sender_address, SPF_PROCESS_NORMAL);
3678 break;
3679 case ACLC_SPF_GUESS:
3680 rc = spf_process(&arg, sender_address, SPF_PROCESS_GUESS);
3681 break;
3682 #endif
3683
3684 case ACLC_UDPSEND:
3685 rc = acl_udpsend(arg, log_msgptr);
3686 break;
3687
3688 /* If the verb is WARN, discard any user message from verification, because
3689 such messages are SMTP responses, not header additions. The latter come
3690 only from explicit "message" modifiers. However, put the user message into
3691 $acl_verify_message so it can be used in subsequent conditions or modifiers
3692 (until something changes it). */
3693
3694 case ACLC_VERIFY:
3695 rc = acl_verify(where, addr, arg, user_msgptr, log_msgptr, basic_errno);
3696 if (*user_msgptr)
3697 acl_verify_message = *user_msgptr;
3698 if (verb == ACL_WARN) *user_msgptr = NULL;
3699 break;
3700
3701 default:
3702 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "internal ACL error: unknown "
3703 "condition %d", cb->type);
3704 break;
3705 }
3706
3707 /* If a condition was negated, invert OK/FAIL. */
3708
3709 if (!conditions[cb->type].is_modifier && cb->u.negated)
3710 if (rc == OK) rc = FAIL;
3711 else if (rc == FAIL || rc == FAIL_DROP) rc = OK;
3712
3713 if (rc != OK) break; /* Conditions loop */
3714 }
3715
3716
3717 /* If the result is the one for which "message" and/or "log_message" are used,
3718 handle the values of these modifiers. If there isn't a log message set, we make
3719 it the same as the user message.
3720
3721 "message" is a user message that will be included in an SMTP response. Unless
3722 it is empty, it overrides any previously set user message.
3723
3724 "log_message" is a non-user message, and it adds to any existing non-user
3725 message that is already set.
3726
3727 Most verbs have but a single return for which the messages are relevant, but
3728 for "discard", it's useful to have the log message both when it succeeds and
3729 when it fails. For "accept", the message is used in the OK case if there is no
3730 "endpass", but (for backwards compatibility) in the FAIL case if "endpass" is
3731 present. */
3732
3733 if (*epp && rc == OK) user_message = NULL;
3734
3735 if ((BIT(rc) & msgcond[verb]) != 0)
3736 {
3737 uschar *expmessage;
3738 uschar *old_user_msgptr = *user_msgptr;
3739 uschar *old_log_msgptr = (*log_msgptr != NULL)? *log_msgptr : old_user_msgptr;
3740
3741 /* If the verb is "warn", messages generated by conditions (verification or
3742 nested ACLs) are always discarded. This also happens for acceptance verbs
3743 when they actually do accept. Only messages specified at this level are used.
3744 However, the value of an existing message is available in $acl_verify_message
3745 during expansions. */
3746
3747 if (verb == ACL_WARN ||
3748 (rc == OK && (verb == ACL_ACCEPT || verb == ACL_DISCARD)))
3749 *log_msgptr = *user_msgptr = NULL;
3750
3751 if (user_message)
3752 {
3753 acl_verify_message = old_user_msgptr;
3754 expmessage = expand_string(user_message);
3755 if (!expmessage)
3756 {
3757 if (!f.expand_string_forcedfail)
3758 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand ACL message \"%s\": %s",
3759 user_message, expand_string_message);
3760 }
3761 else if (expmessage[0] != 0) *user_msgptr = expmessage;
3762 }
3763
3764 if (log_message)
3765 {
3766 acl_verify_message = old_log_msgptr;
3767 expmessage = expand_string(log_message);
3768 if (!expmessage)
3769 {
3770 if (!f.expand_string_forcedfail)
3771 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand ACL message \"%s\": %s",
3772 log_message, expand_string_message);
3773 }
3774 else if (expmessage[0] != 0)
3775 {
3776 *log_msgptr = (*log_msgptr == NULL)? expmessage :
3777 string_sprintf("%s: %s", expmessage, *log_msgptr);
3778 }
3779 }
3780
3781 /* If no log message, default it to the user message */
3782
3783 if (!*log_msgptr) *log_msgptr = *user_msgptr;
3784 }
3785
3786 acl_verify_message = NULL;
3787 return rc;
3788 }
3789
3790
3791
3792
3793
3794 /*************************************************
3795 * Get line from a literal ACL *
3796 *************************************************/
3797
3798 /* This function is passed to acl_read() in order to extract individual lines
3799 of a literal ACL, which we access via static pointers. We can destroy the
3800 contents because this is called only once (the compiled ACL is remembered).
3801
3802 This code is intended to treat the data in the same way as lines in the main
3803 Exim configuration file. That is:
3804
3805 . Leading spaces are ignored.
3806
3807 . A \ at the end of a line is a continuation - trailing spaces after the \
3808 are permitted (this is because I don't believe in making invisible things
3809 significant). Leading spaces on the continued part of a line are ignored.
3810
3811 . Physical lines starting (significantly) with # are totally ignored, and
3812 may appear within a sequence of backslash-continued lines.
3813
3814 . Blank lines are ignored, but will end a sequence of continuations.
3815
3816 Arguments: none
3817 Returns: a pointer to the next line
3818 */
3819
3820
3821 static uschar *acl_text; /* Current pointer in the text */
3822 static uschar *acl_text_end; /* Points one past the terminating '0' */
3823
3824
3825 static uschar *
3826 acl_getline(void)
3827 {
3828 uschar *yield;
3829
3830 /* This loop handles leading blank lines and comments. */
3831
3832 for(;;)
3833 {
3834 while (isspace(*acl_text)) acl_text++; /* Leading spaces/empty lines */
3835 if (*acl_text == 0) return NULL; /* No more data */
3836 yield = acl_text; /* Potential data line */
3837
3838 while (*acl_text && *acl_text != '\n') acl_text++;
3839
3840 /* If we hit the end before a newline, we have the whole logical line. If
3841 it's a comment, there's no more data to be given. Otherwise, yield it. */
3842
3843 if (*acl_text == 0) return (*yield == '#')? NULL : yield;
3844
3845 /* After reaching a newline, end this loop if the physical line does not
3846 start with '#'. If it does, it's a comment, and the loop continues. */
3847
3848 if (*yield != '#') break;
3849 }
3850
3851 /* This loop handles continuations. We know we have some real data, ending in
3852 newline. See if there is a continuation marker at the end (ignoring trailing
3853 white space). We know that *yield is not white space, so no need to test for
3854 cont > yield in the backwards scanning loop. */
3855
3856 for(;;)
3857 {
3858 uschar *cont;
3859 for (cont = acl_text - 1; isspace(*cont); cont--);
3860
3861 /* If no continuation follows, we are done. Mark the end of the line and
3862 return it. */
3863
3864 if (*cont != '\\')
3865 {
3866 *acl_text++ = 0;
3867 return yield;
3868 }
3869
3870 /* We have encountered a continuation. Skip over whitespace at the start of
3871 the next line, and indeed the whole of the next line or lines if they are
3872 comment lines. */
3873
3874 for (;;)
3875 {
3876 while (*(++acl_text) == ' ' || *acl_text == '\t');
3877 if (*acl_text != '#') break;
3878 while (*(++acl_text) != 0 && *acl_text != '\n');
3879 }
3880
3881 /* We have the start of a continuation line. Move all the rest of the data
3882 to join onto the previous line, and then find its end. If the end is not a
3883 newline, we are done. Otherwise loop to look for another continuation. */
3884
3885 memmove(cont, acl_text, acl_text_end - acl_text);
3886 acl_text_end -= acl_text - cont;
3887 acl_text = cont;
3888 while (*acl_text != 0 && *acl_text != '\n') acl_text++;
3889 if (*acl_text == 0) return yield;
3890 }
3891
3892 /* Control does not reach here */
3893 }
3894
3895
3896
3897
3898
3899 /*************************************************
3900 * Check access using an ACL *
3901 *************************************************/
3902
3903 /* This function is called from address_check. It may recurse via
3904 acl_check_condition() - hence the use of a level to stop looping. The ACL is
3905 passed as a string which is expanded. A forced failure implies no access check
3906 is required. If the result is a single word, it is taken as the name of an ACL
3907 which is sought in the global ACL tree. Otherwise, it is taken as literal ACL
3908 text, complete with newlines, and parsed as such. In both cases, the ACL check
3909 is then run. This function uses an auxiliary function for acl_read() to call
3910 for reading individual lines of a literal ACL. This is acl_getline(), which
3911 appears immediately above.
3912
3913 Arguments:
3914 where where called from
3915 addr address item when called from RCPT; otherwise NULL
3916 s the input string; NULL is the same as an empty ACL => DENY
3917 user_msgptr where to put a user error (for SMTP response)
3918 log_msgptr where to put a logging message (not for SMTP response)
3919
3920 Returns: OK access is granted
3921 DISCARD access is apparently granted...
3922 FAIL access is denied
3923 FAIL_DROP access is denied; drop the connection
3924 DEFER can't tell at the moment
3925 ERROR disaster
3926 */
3927
3928 static int
3929 acl_check_internal(int where, address_item *addr, uschar *s,
3930 uschar **user_msgptr, uschar **log_msgptr)
3931 {
3932 int fd = -1;
3933 acl_block *acl = NULL;
3934 uschar *acl_name = US"inline ACL";
3935 uschar *ss;
3936
3937 /* Catch configuration loops */
3938
3939 if (acl_level > 20)
3940 {
3941 *log_msgptr = US"ACL nested too deep: possible loop";
3942 return ERROR;
3943 }
3944
3945 if (!s)
3946 {
3947 HDEBUG(D_acl) debug_printf_indent("ACL is NULL: implicit DENY\n");
3948 return FAIL;
3949 }
3950
3951 /* At top level, we expand the incoming string. At lower levels, it has already
3952 been expanded as part of condition processing. */
3953
3954 if (acl_level == 0)
3955 {
3956 if (!(ss = expand_string(s)))
3957 {
3958 if (f.expand_string_forcedfail) return OK;
3959 *log_msgptr = string_sprintf("failed to expand ACL string \"%s\": %s", s,
3960 expand_string_message);
3961 return ERROR;
3962 }
3963 }
3964 else ss = s;
3965
3966 while (isspace(*ss)) ss++;
3967
3968 /* If we can't find a named ACL, the default is to parse it as an inline one.
3969 (Unless it begins with a slash; non-existent files give rise to an error.) */
3970
3971 acl_text = ss;
3972
3973 /* Handle the case of a string that does not contain any spaces. Look for a
3974 named ACL among those read from the configuration, or a previously read file.
3975 It is possible that the pointer to the ACL is NULL if the configuration
3976 contains a name with no data. If not found, and the text begins with '/',
3977 read an ACL from a file, and save it so it can be re-used. */
3978
3979 if (Ustrchr(ss, ' ') == NULL)
3980 {
3981 tree_node * t = tree_search(acl_anchor, ss);
3982 if (t)
3983 {
3984 if (!(acl = (acl_block *)(t->data.ptr)))
3985 {
3986 HDEBUG(D_acl) debug_printf_indent("ACL \"%s\" is empty: implicit DENY\n", ss);
3987 return FAIL;
3988 }
3989 acl_name = string_sprintf("ACL \"%s\"", ss);
3990 HDEBUG(D_acl) debug_printf_indent("using ACL \"%s\"\n", ss);
3991 }
3992
3993 else if (*ss == '/')
3994 {
3995 struct stat statbuf;
3996 if (is_tainted(ss))
3997 {
3998 log_write(0, LOG_MAIN|LOG_PANIC,
3999 "attempt to open tainted ACL file name \"%s\"", ss);
4000 /* Avoid leaking info to an attacker */
4001 *log_msgptr = US"internal configuration error";
4002 return ERROR;
4003 }
4004 if ((fd = Uopen(ss, O_RDONLY, 0)) < 0)
4005 {
4006 *log_msgptr = string_sprintf("failed to open ACL file \"%s\": %s", ss,
4007 strerror(errno));
4008 return ERROR;
4009 }
4010 if (fstat(fd, &statbuf) != 0)
4011 {
4012 *log_msgptr = string_sprintf("failed to fstat ACL file \"%s\": %s", ss,
4013 strerror(errno));
4014 return ERROR;
4015 }
4016
4017 /* If the string being used as a filename is tainted, so is the file content */
4018 acl_text = store_get(statbuf.st_size + 1, is_tainted(ss));
4019 acl_text_end = acl_text + statbuf.st_size + 1;
4020
4021 if (read(fd, acl_text, statbuf.st_size) != statbuf.st_size)
4022 {
4023 *log_msgptr = string_sprintf("failed to read ACL file \"%s\": %s",
4024 ss, strerror(errno));
4025 return ERROR;
4026 }
4027 acl_text[statbuf.st_size] = 0;
4028 (void)close(fd);
4029
4030 acl_name = string_sprintf("ACL \"%s\"", ss);
4031 HDEBUG(D_acl) debug_printf_indent("read ACL from file %s\n", ss);
4032 }
4033 }
4034
4035 /* Parse an ACL that is still in text form. If it came from a file, remember it
4036 in the ACL tree, having read it into the POOL_PERM store pool so that it
4037 persists between multiple messages. */
4038
4039 if (!acl)
4040 {
4041 int old_pool = store_pool;
4042 if (fd >= 0) store_pool = POOL_PERM;
4043 acl = acl_read(acl_getline, log_msgptr);
4044 store_pool = old_pool;
4045 if (!acl && *log_msgptr) return ERROR;