1 /* $Cambridge: exim/src/src/acl.c,v 1.88 2010/06/06 00:27:52 pdp Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2009 */
8 /* See the file NOTICE for conditions of use and distribution. */
10 /* Code for handling Access Control Lists (ACLs) */
15 /* Default callout timeout */
17 #define CALLOUT_TIMEOUT_DEFAULT 30
19 /* ACL verb codes - keep in step with the table of verbs that follows */
21 enum { ACL_ACCEPT, ACL_DEFER, ACL_DENY, ACL_DISCARD, ACL_DROP, ACL_REQUIRE,
26 static uschar *verbs[] =
27 { US"accept", US"defer", US"deny", US"discard", US"drop", US"require",
30 /* For each verb, the conditions for which "message" or "log_message" are used
31 are held as a bitmap. This is to avoid expanding the strings unnecessarily. For
32 "accept", the FAIL case is used only after "endpass", but that is selected in
35 static int msgcond[] = {
36 (1<<OK) | (1<<FAIL) | (1<<FAIL_DROP), /* accept */
39 (1<<OK) | (1<<FAIL) | (1<<FAIL_DROP), /* discard */
41 (1<<FAIL) | (1<<FAIL_DROP), /* require */
45 /* ACL condition and modifier codes - keep in step with the table that
46 follows, and the cond_expand_at_top and uschar cond_modifiers tables lower
52 #ifdef EXPERIMENTAL_BRIGHTMAIL
58 #ifdef EXPERIMENTAL_DCC
61 #ifdef WITH_CONTENT_SCAN
65 #ifdef WITH_OLD_DEMIME
79 ACLC_LOG_REJECT_TARGET,
81 #ifdef WITH_CONTENT_SCAN
85 #ifdef WITH_CONTENT_SCAN
90 #ifdef WITH_CONTENT_SCAN
96 #ifdef WITH_CONTENT_SCAN
99 #ifdef EXPERIMENTAL_SPF
105 /* ACL conditions/modifiers: "delay", "control", "continue", "endpass",
106 "message", "log_message", "log_reject_target", "logwrite", and "set" are
107 modifiers that look like conditions but always return TRUE. They are used for
108 their side effects. */
110 static uschar *conditions[] = {
114 #ifdef EXPERIMENTAL_BRIGHTMAIL
120 #ifdef EXPERIMENTAL_DCC
123 #ifdef WITH_CONTENT_SCAN
127 #ifdef WITH_OLD_DEMIME
141 US"log_reject_target",
143 #ifdef WITH_CONTENT_SCAN
147 #ifdef WITH_CONTENT_SCAN
152 #ifdef WITH_CONTENT_SCAN
155 US"sender_domains", US"senders", US"set",
156 #ifdef WITH_CONTENT_SCAN
159 #ifdef EXPERIMENTAL_SPF
166 /* Return values from decode_control(); keep in step with the table of names
170 CONTROL_AUTH_UNADVERTISED,
171 #ifdef EXPERIMENTAL_BRIGHTMAIL
179 CONTROL_CASEFUL_LOCAL_PART,
180 CONTROL_CASELOWER_LOCAL_PART,
181 CONTROL_ENFORCE_SYNC,
182 CONTROL_NO_ENFORCE_SYNC,
186 CONTROL_SUPPRESS_LOCAL_FIXUPS,
187 #ifdef WITH_CONTENT_SCAN
188 CONTROL_NO_MBOX_UNSPOOL,
192 CONTROL_NO_MULTILINE,
193 CONTROL_NO_PIPELINING,
194 CONTROL_NO_DELAY_FLUSH,
195 CONTROL_NO_CALLOUT_FLUSH
198 /* ACL control names; keep in step with the table above! This list is used for
199 turning ids into names. The actual list of recognized names is in the variable
200 control_def controls_list[] below. The fact that there are two lists is a mess
201 and should be tidied up. */
203 static uschar *controls[] = {
204 US"allow_auth_unadvertised",
205 #ifdef EXPERIMENTAL_BRIGHTMAIL
210 US"dkim_disable_verify",
213 US"caseful_local_part",
214 US"caselower_local_part",
220 US"suppress_local_fixups",
221 #ifdef WITH_CONTENT_SCAN
226 US"no_multiline_responses",
232 /* Flags to indicate for which conditions/modifiers a string expansion is done
233 at the outer level. In the other cases, expansion already occurs in the
234 checking functions. */
236 static uschar cond_expand_at_top[] = {
238 TRUE, /* add_header */
239 FALSE, /* authenticated */
240 #ifdef EXPERIMENTAL_BRIGHTMAIL
241 TRUE, /* bmi_optin */
243 TRUE, /* condition */
246 #ifdef EXPERIMENTAL_DCC
249 #ifdef WITH_CONTENT_SCAN
253 #ifdef WITH_OLD_DEMIME
257 TRUE, /* dkim_signers */
258 TRUE, /* dkim_status */
262 FALSE, /* encrypted */
265 FALSE, /* local_parts */
266 TRUE, /* log_message */
267 TRUE, /* log_reject_target */
269 #ifdef WITH_CONTENT_SCAN
273 #ifdef WITH_CONTENT_SCAN
274 TRUE, /* mime_regex */
276 TRUE, /* ratelimit */
277 FALSE, /* recipients */
278 #ifdef WITH_CONTENT_SCAN
281 FALSE, /* sender_domains */
284 #ifdef WITH_CONTENT_SCAN
287 #ifdef EXPERIMENTAL_SPF
289 TRUE, /* spf_guess */
294 /* Flags to identify the modifiers */
296 static uschar cond_modifiers[] = {
298 TRUE, /* add_header */
299 FALSE, /* authenticated */
300 #ifdef EXPERIMENTAL_BRIGHTMAIL
301 TRUE, /* bmi_optin */
303 FALSE, /* condition */
306 #ifdef EXPERIMENTAL_DCC
309 #ifdef WITH_CONTENT_SCAN
313 #ifdef WITH_OLD_DEMIME
317 FALSE, /* dkim_signers */
318 FALSE, /* dkim_status */
320 FALSE, /* dnslists */
322 FALSE, /* encrypted */
325 FALSE, /* local_parts */
326 TRUE, /* log_message */
327 TRUE, /* log_reject_target */
329 #ifdef WITH_CONTENT_SCAN
333 #ifdef WITH_CONTENT_SCAN
334 FALSE, /* mime_regex */
336 FALSE, /* ratelimit */
337 FALSE, /* recipients */
338 #ifdef WITH_CONTENT_SCAN
341 FALSE, /* sender_domains */
344 #ifdef WITH_CONTENT_SCAN
347 #ifdef EXPERIMENTAL_SPF
349 FALSE, /* spf_guess */
354 /* Bit map vector of which conditions and modifiers are not allowed at certain
355 times. For each condition and modifier, there's a bitmap of dis-allowed times.
356 For some, it is easier to specify the negation of a small number of allowed
359 static unsigned int cond_forbids[] = {
363 ~((1<<ACL_WHERE_MAIL)|(1<<ACL_WHERE_RCPT)| /* add_header */
364 (1<<ACL_WHERE_PREDATA)|(1<<ACL_WHERE_DATA)|
365 (1<<ACL_WHERE_MIME)|(1<<ACL_WHERE_NOTSMTP)|
367 (1<<ACL_WHERE_NOTSMTP_START)),
369 (1<<ACL_WHERE_NOTSMTP)| /* authenticated */
370 (1<<ACL_WHERE_NOTSMTP_START)|
371 (1<<ACL_WHERE_CONNECT)|(1<<ACL_WHERE_HELO),
373 #ifdef EXPERIMENTAL_BRIGHTMAIL
374 (1<<ACL_WHERE_AUTH)| /* bmi_optin */
375 (1<<ACL_WHERE_CONNECT)|(1<<ACL_WHERE_HELO)|
376 (1<<ACL_WHERE_DATA)|(1<<ACL_WHERE_MIME)|
377 (1<<ACL_WHERE_ETRN)|(1<<ACL_WHERE_EXPN)|
378 (1<<ACL_WHERE_MAILAUTH)|
379 (1<<ACL_WHERE_MAIL)|(1<<ACL_WHERE_STARTTLS)|
380 (1<<ACL_WHERE_VRFY)|(1<<ACL_WHERE_PREDATA)|
381 (1<<ACL_WHERE_NOTSMTP_START),
388 /* Certain types of control are always allowed, so we let it through
389 always and check in the control processing itself. */
393 #ifdef EXPERIMENTAL_DCC
395 ~((1<<ACL_WHERE_DATA)|(1<<ACL_WHERE_NOTSMTP)), /* dcc */
398 #ifdef WITH_CONTENT_SCAN
400 ~(1<<ACL_WHERE_MIME), /* decode */
403 (1<<ACL_WHERE_NOTQUIT), /* delay */
405 #ifdef WITH_OLD_DEMIME
407 ~((1<<ACL_WHERE_DATA)|(1<<ACL_WHERE_NOTSMTP)), /* demime */
412 ~(1<<ACL_WHERE_DKIM), /* dkim_signers */
415 ~(1<<ACL_WHERE_DKIM), /* dkim_status */
418 (1<<ACL_WHERE_NOTSMTP)| /* dnslists */
419 (1<<ACL_WHERE_NOTSMTP_START),
422 ~(1<<ACL_WHERE_RCPT), /* domains */
424 (1<<ACL_WHERE_NOTSMTP)| /* encrypted */
425 (1<<ACL_WHERE_CONNECT)|
426 (1<<ACL_WHERE_NOTSMTP_START)|
431 (1<<ACL_WHERE_NOTSMTP)| /* hosts */
432 (1<<ACL_WHERE_NOTSMTP_START),
435 ~(1<<ACL_WHERE_RCPT), /* local_parts */
439 0, /* log_reject_target */
443 #ifdef WITH_CONTENT_SCAN
445 ~((1<<ACL_WHERE_DATA)|(1<<ACL_WHERE_NOTSMTP)), /* malware */
450 #ifdef WITH_CONTENT_SCAN
452 ~(1<<ACL_WHERE_MIME), /* mime_regex */
458 ~(1<<ACL_WHERE_RCPT), /* recipients */
460 #ifdef WITH_CONTENT_SCAN
462 ~((1<<ACL_WHERE_DATA)|(1<<ACL_WHERE_NOTSMTP)| /* regex */
463 (1<<ACL_WHERE_MIME)),
466 (1<<ACL_WHERE_AUTH)|(1<<ACL_WHERE_CONNECT)| /* sender_domains */
468 (1<<ACL_WHERE_MAILAUTH)|(1<<ACL_WHERE_QUIT)|
469 (1<<ACL_WHERE_ETRN)|(1<<ACL_WHERE_EXPN)|
470 (1<<ACL_WHERE_STARTTLS)|(1<<ACL_WHERE_VRFY),
472 (1<<ACL_WHERE_AUTH)|(1<<ACL_WHERE_CONNECT)| /* senders */
474 (1<<ACL_WHERE_MAILAUTH)|(1<<ACL_WHERE_QUIT)|
475 (1<<ACL_WHERE_ETRN)|(1<<ACL_WHERE_EXPN)|
476 (1<<ACL_WHERE_STARTTLS)|(1<<ACL_WHERE_VRFY),
480 #ifdef WITH_CONTENT_SCAN
482 ~((1<<ACL_WHERE_DATA)|(1<<ACL_WHERE_NOTSMTP)), /* spam */
485 #ifdef EXPERIMENTAL_SPF
486 (1<<ACL_WHERE_AUTH)|(1<<ACL_WHERE_CONNECT)| /* spf */
488 (1<<ACL_WHERE_MAILAUTH)|
489 (1<<ACL_WHERE_ETRN)|(1<<ACL_WHERE_EXPN)|
490 (1<<ACL_WHERE_STARTTLS)|(1<<ACL_WHERE_VRFY)|
491 (1<<ACL_WHERE_NOTSMTP)|
492 (1<<ACL_WHERE_NOTSMTP_START),
494 (1<<ACL_WHERE_AUTH)|(1<<ACL_WHERE_CONNECT)| /* spf_guess */
496 (1<<ACL_WHERE_MAILAUTH)|
497 (1<<ACL_WHERE_ETRN)|(1<<ACL_WHERE_EXPN)|
498 (1<<ACL_WHERE_STARTTLS)|(1<<ACL_WHERE_VRFY)|
499 (1<<ACL_WHERE_NOTSMTP)|
500 (1<<ACL_WHERE_NOTSMTP_START),
503 /* Certain types of verify are always allowed, so we let it through
504 always and check in the verify function itself */
510 /* Bit map vector of which controls are not allowed at certain times. For
511 each control, there's a bitmap of dis-allowed times. For some, it is easier to
512 specify the negation of a small number of allowed times. */
514 static unsigned int control_forbids[] = {
516 ~((1<<ACL_WHERE_CONNECT)|(1<<ACL_WHERE_HELO)), /* allow_auth_unadvertised */
518 #ifdef EXPERIMENTAL_BRIGHTMAIL
525 (1<<ACL_WHERE_DATA)|(1<<ACL_WHERE_NOTSMTP)| /* dkim_disable_verify */
526 (1<<ACL_WHERE_NOTSMTP_START),
532 ~(1<<ACL_WHERE_RCPT), /* caseful_local_part */
535 ~(1<<ACL_WHERE_RCPT), /* caselower_local_part */
537 (1<<ACL_WHERE_NOTSMTP)| /* enforce_sync */
538 (1<<ACL_WHERE_NOTSMTP_START),
540 (1<<ACL_WHERE_NOTSMTP)| /* no_enforce_sync */
541 (1<<ACL_WHERE_NOTSMTP_START),
544 ~((1<<ACL_WHERE_MAIL)|(1<<ACL_WHERE_RCPT)| /* freeze */
545 (1<<ACL_WHERE_PREDATA)|(1<<ACL_WHERE_DATA)|
546 (1<<ACL_WHERE_NOTSMTP)|(1<<ACL_WHERE_MIME)),
549 ~((1<<ACL_WHERE_MAIL)|(1<<ACL_WHERE_RCPT)| /* queue_only */
550 (1<<ACL_WHERE_PREDATA)|(1<<ACL_WHERE_DATA)|
551 (1<<ACL_WHERE_NOTSMTP)|(1<<ACL_WHERE_MIME)),
554 ~((1<<ACL_WHERE_MAIL)|(1<<ACL_WHERE_RCPT)| /* submission */
555 (1<<ACL_WHERE_PREDATA)),
558 ~((1<<ACL_WHERE_MAIL)|(1<<ACL_WHERE_RCPT)| /* suppress_local_fixups */
559 (1<<ACL_WHERE_PREDATA)|
560 (1<<ACL_WHERE_NOTSMTP_START)),
562 #ifdef WITH_CONTENT_SCAN
564 ~((1<<ACL_WHERE_MAIL)|(1<<ACL_WHERE_RCPT)| /* no_mbox_unspool */
565 (1<<ACL_WHERE_PREDATA)|(1<<ACL_WHERE_DATA)|
566 (1<<ACL_WHERE_MIME)),
570 ~((1<<ACL_WHERE_MAIL)|(1<<ACL_WHERE_RCPT)| /* fakedefer */
571 (1<<ACL_WHERE_PREDATA)|(1<<ACL_WHERE_DATA)|
572 (1<<ACL_WHERE_MIME)),
575 ~((1<<ACL_WHERE_MAIL)|(1<<ACL_WHERE_RCPT)| /* fakereject */
576 (1<<ACL_WHERE_PREDATA)|(1<<ACL_WHERE_DATA)|
577 (1<<ACL_WHERE_MIME)),
579 (1<<ACL_WHERE_NOTSMTP)| /* no_multiline */
580 (1<<ACL_WHERE_NOTSMTP_START),
582 (1<<ACL_WHERE_NOTSMTP)| /* no_pipelining */
583 (1<<ACL_WHERE_NOTSMTP_START),
585 (1<<ACL_WHERE_NOTSMTP)| /* no_delay_flush */
586 (1<<ACL_WHERE_NOTSMTP_START),
588 (1<<ACL_WHERE_NOTSMTP)| /* no_callout_flush */
589 (1<<ACL_WHERE_NOTSMTP_START)
592 /* Structure listing various control arguments, with their characteristics. */
594 typedef struct control_def {
596 int value; /* CONTROL_xxx value */
597 BOOL has_option; /* Has /option(s) following */
600 static control_def controls_list[] = {
601 { US"allow_auth_unadvertised", CONTROL_AUTH_UNADVERTISED, FALSE },
602 #ifdef EXPERIMENTAL_BRIGHTMAIL
603 { US"bmi_run", CONTROL_BMI_RUN, FALSE },
605 { US"debug", CONTROL_DEBUG, TRUE },
607 { US"dkim_disable_verify", CONTROL_DKIM_VERIFY, FALSE },
609 { US"caseful_local_part", CONTROL_CASEFUL_LOCAL_PART, FALSE },
610 { US"caselower_local_part", CONTROL_CASELOWER_LOCAL_PART, FALSE },
611 { US"enforce_sync", CONTROL_ENFORCE_SYNC, FALSE },
612 { US"freeze", CONTROL_FREEZE, TRUE },
613 { US"no_callout_flush", CONTROL_NO_CALLOUT_FLUSH, FALSE },
614 { US"no_delay_flush", CONTROL_NO_DELAY_FLUSH, FALSE },
615 { US"no_enforce_sync", CONTROL_NO_ENFORCE_SYNC, FALSE },
616 { US"no_multiline_responses", CONTROL_NO_MULTILINE, FALSE },
617 { US"no_pipelining", CONTROL_NO_PIPELINING, FALSE },
618 { US"queue_only", CONTROL_QUEUE_ONLY, FALSE },
619 #ifdef WITH_CONTENT_SCAN
620 { US"no_mbox_unspool", CONTROL_NO_MBOX_UNSPOOL, FALSE },
622 { US"fakedefer", CONTROL_FAKEDEFER, TRUE },
623 { US"fakereject", CONTROL_FAKEREJECT, TRUE },
624 { US"submission", CONTROL_SUBMISSION, TRUE },
625 { US"suppress_local_fixups", CONTROL_SUPPRESS_LOCAL_FIXUPS, FALSE }
628 /* Support data structures for Client SMTP Authorization. acl_verify_csa()
629 caches its result in a tree to avoid repeated DNS queries. The result is an
630 integer code which is used as an index into the following tables of
631 explanatory strings and verification return codes. */
633 static tree_node *csa_cache = NULL;
635 enum { CSA_UNKNOWN, CSA_OK, CSA_DEFER_SRV, CSA_DEFER_ADDR,
636 CSA_FAIL_EXPLICIT, CSA_FAIL_DOMAIN, CSA_FAIL_NOADDR, CSA_FAIL_MISMATCH };
638 /* The acl_verify_csa() return code is translated into an acl_verify() return
639 code using the following table. It is OK unless the client is definitely not
640 authorized. This is because CSA is supposed to be optional for sending sites,
641 so recipients should not be too strict about checking it - especially because
642 DNS problems are quite likely to occur. It's possible to use $csa_status in
643 further ACL conditions to distinguish ok, unknown, and defer if required, but
644 the aim is to make the usual configuration simple. */
646 static int csa_return_code[] = {
648 FAIL, FAIL, FAIL, FAIL
651 static uschar *csa_status_string[] = {
652 US"unknown", US"ok", US"defer", US"defer",
653 US"fail", US"fail", US"fail", US"fail"
656 static uschar *csa_reason_string[] = {
659 US"deferred (SRV lookup failed)",
660 US"deferred (target address lookup failed)",
661 US"failed (explicit authorization required)",
662 US"failed (host name not authorized)",
663 US"failed (no authorized addresses)",
664 US"failed (client address mismatch)"
667 /* Options for the ratelimit condition. Note that there are two variants of
668 the per_rcpt option, depending on the ACL that is used to measure the rate.
669 However any ACL must be able to look up per_rcpt rates in /noupdate mode,
670 so the two variants must have the same internal representation as well as
671 the same configuration string. */
674 RATE_PER_WHAT, RATE_PER_CLASH, RATE_PER_ADDR, RATE_PER_BYTE, RATE_PER_CMD,
675 RATE_PER_CONN, RATE_PER_MAIL, RATE_PER_RCPT, RATE_PER_ALLRCPTS
678 #define RATE_SET(var,new) \
679 (((var) == RATE_PER_WHAT) ? ((var) = RATE_##new) : ((var) = RATE_PER_CLASH))
681 static uschar *ratelimit_option_string[] = {
682 US"?", US"!", US"per_addr", US"per_byte", US"per_cmd",
683 US"per_conn", US"per_mail", US"per_rcpt", US"per_rcpt"
686 /* Enable recursion between acl_check_internal() and acl_check_condition() */
688 static int acl_check_internal(int, address_item *, uschar *, int, uschar **,
692 /*************************************************
693 * Pick out name from list *
694 *************************************************/
696 /* Use a binary chop method
703 Returns: offset in list, or -1 if not found
707 acl_checkname(uschar *name, uschar **list, int end)
713 int mid = (start + end)/2;
714 int c = Ustrcmp(name, list[mid]);
715 if (c == 0) return mid;
716 if (c < 0) end = mid; else start = mid + 1;
723 /*************************************************
724 * Read and parse one ACL *
725 *************************************************/
727 /* This function is called both from readconf in order to parse the ACLs in the
728 configuration file, and also when an ACL is encountered dynamically (e.g. as
729 the result of an expansion). It is given a function to call in order to
730 retrieve the lines of the ACL. This function handles skipping comments and
731 blank lines (where relevant).
734 func function to get next line of ACL
735 error where to put an error message
737 Returns: pointer to ACL, or NULL
738 NULL can be legal (empty ACL); in this case error will be NULL
742 acl_read(uschar *(*func)(void), uschar **error)
744 acl_block *yield = NULL;
745 acl_block **lastp = &yield;
746 acl_block *this = NULL;
747 acl_condition_block *cond;
748 acl_condition_block **condp = NULL;
753 while ((s = (*func)()) != NULL)
756 BOOL negated = FALSE;
757 uschar *saveline = s;
760 /* Conditions (but not verbs) are allowed to be negated by an initial
763 while (isspace(*s)) s++;
770 /* Read the name of a verb or a condition, or the start of a new ACL, which
771 can be started by a name, or by a macro definition. */
773 s = readconf_readname(name, sizeof(name), s);
774 if (*s == ':' || (isupper(name[0]) && *s == '=')) return yield;
776 /* If a verb is unrecognized, it may be another condition or modifier that
777 continues the previous verb. */
779 v = acl_checkname(name, verbs, sizeof(verbs)/sizeof(char *));
784 *error = string_sprintf("unknown ACL verb \"%s\" in \"%s\"", name,
796 *error = string_sprintf("malformed ACL line \"%s\"", saveline);
799 this = store_get(sizeof(acl_block));
801 lastp = &(this->next);
804 this->condition = NULL;
805 condp = &(this->condition);
806 if (*s == 0) continue; /* No condition on this line */
812 s = readconf_readname(name, sizeof(name), s); /* Condition name */
815 /* Handle a condition or modifier. */
817 c = acl_checkname(name, conditions, sizeof(conditions)/sizeof(char *));
820 *error = string_sprintf("unknown ACL condition/modifier in \"%s\"",
825 /* The modifiers may not be negated */
827 if (negated && cond_modifiers[c])
829 *error = string_sprintf("ACL error: negation is not allowed with "
830 "\"%s\"", conditions[c]);
834 /* ENDPASS may occur only with ACCEPT or DISCARD. */
836 if (c == ACLC_ENDPASS &&
837 this->verb != ACL_ACCEPT &&
838 this->verb != ACL_DISCARD)
840 *error = string_sprintf("ACL error: \"%s\" is not allowed with \"%s\"",
841 conditions[c], verbs[this->verb]);
845 cond = store_get(sizeof(acl_condition_block));
848 cond->u.negated = negated;
851 condp = &(cond->next);
853 /* The "set" modifier is different in that its argument is "name=value"
854 rather than just a value, and we can check the validity of the name, which
855 gives us a variable name to insert into the data block. The original ACL
856 variable names were acl_c0 ... acl_c9 and acl_m0 ... acl_m9. This was
857 extended to 20 of each type, but after that people successfully argued for
858 arbitrary names. In the new scheme, the names must start with acl_c or acl_m.
859 After that, we allow alphanumerics and underscores, but the first character
860 after c or m must be a digit or an underscore. This retains backwards
867 if (Ustrncmp(s, "acl_c", 5) != 0 &&
868 Ustrncmp(s, "acl_m", 5) != 0)
870 *error = string_sprintf("invalid variable name after \"set\" in ACL "
871 "modifier \"set %s\" (must start \"acl_c\" or \"acl_m\")", s);
876 if (!isdigit(*endptr) && *endptr != '_')
878 *error = string_sprintf("invalid variable name after \"set\" in ACL "
879 "modifier \"set %s\" (digit or underscore must follow acl_c or acl_m)",
884 while (*endptr != 0 && *endptr != '=' && !isspace(*endptr))
886 if (!isalnum(*endptr) && *endptr != '_')
888 *error = string_sprintf("invalid character \"%c\" in variable name "
889 "in ACL modifier \"set %s\"", *endptr, s);
895 cond->u.varname = string_copyn(s + 4, endptr - s - 4);
897 while (isspace(*s)) s++;
900 /* For "set", we are now positioned for the data. For the others, only
901 "endpass" has no data */
903 if (c != ACLC_ENDPASS)
907 *error = string_sprintf("\"=\" missing after ACL \"%s\" %s", name,
908 cond_modifiers[c]? US"modifier" : US"condition");
911 while (isspace(*s)) s++;
912 cond->arg = string_copy(s);
921 /*************************************************
922 * Set up added header line(s) *
923 *************************************************/
925 /* This function is called by the add_header modifier, and also from acl_warn()
926 to implement the now-deprecated way of adding header lines using "message" on a
927 "warn" verb. The argument is treated as a sequence of header lines which are
928 added to a chain, provided there isn't an identical one already there.
930 Argument: string of header lines
935 setup_header(uschar *hstring)
938 int hlen = Ustrlen(hstring);
940 /* An empty string does nothing; otherwise add a final newline if necessary. */
942 if (hlen <= 0) return;
943 if (hstring[hlen-1] != '\n') hstring = string_sprintf("%s\n", hstring);
945 /* Loop for multiple header lines, taking care about continuations */
947 for (p = q = hstring; *p != 0; )
950 int newtype = htype_add_bot;
951 header_line **hptr = &acl_added_headers;
953 /* Find next header line within the string */
957 q = Ustrchr(q, '\n');
958 if (*(++q) != ' ' && *q != '\t') break;
961 /* If the line starts with a colon, interpret the instruction for where to
962 add it. This temporarily sets up a new type. */
966 if (strncmpic(p, US":after_received:", 16) == 0)
968 newtype = htype_add_rec;
971 else if (strncmpic(p, US":at_start_rfc:", 14) == 0)
973 newtype = htype_add_rfc;
976 else if (strncmpic(p, US":at_start:", 10) == 0)
978 newtype = htype_add_top;
981 else if (strncmpic(p, US":at_end:", 8) == 0)
983 newtype = htype_add_bot;
986 while (*p == ' ' || *p == '\t') p++;
989 /* See if this line starts with a header name, and if not, add X-ACL-Warn:
990 to the front of it. */
992 for (s = p; s < q - 1; s++)
994 if (*s == ':' || !isgraph(*s)) break;
997 s = string_sprintf("%s%.*s", (*s == ':')? "" : "X-ACL-Warn: ", q - p, p);
1000 /* See if this line has already been added */
1002 while (*hptr != NULL)
1004 if (Ustrncmp((*hptr)->text, s, hlen) == 0) break;
1005 hptr = &((*hptr)->next);
1008 /* Add if not previously present */
1012 header_line *h = store_get(sizeof(header_line));
1021 /* Advance for next header line within the string */
1030 /*************************************************
1032 *************************************************/
1034 /* This function is called when a WARN verb's conditions are true. It adds to
1035 the message's headers, and/or writes information to the log. In each case, this
1036 only happens once (per message for headers, per connection for log).
1038 ** NOTE: The header adding action using the "message" setting is historic, and
1039 its use is now deprecated. The new add_header modifier should be used instead.
1042 where ACL_WHERE_xxxx indicating which ACL this is
1043 user_message message for adding to headers
1044 log_message message for logging, if different
1050 acl_warn(int where, uschar *user_message, uschar *log_message)
1052 if (log_message != NULL && log_message != user_message)
1055 string_item *logged;
1057 text = string_sprintf("%s Warning: %s", host_and_ident(TRUE),
1058 string_printing(log_message));
1060 /* If a sender verification has failed, and the log message is "sender verify
1061 failed", add the failure message. */
1063 if (sender_verified_failed != NULL &&
1064 sender_verified_failed->message != NULL &&
1065 strcmpic(log_message, US"sender verify failed") == 0)
1066 text = string_sprintf("%s: %s", text, sender_verified_failed->message);
1068 /* Search previously logged warnings. They are kept in malloc
1069 store so they can be freed at the start of a new message. */
1071 for (logged = acl_warn_logged; logged != NULL; logged = logged->next)
1072 if (Ustrcmp(logged->text, text) == 0) break;
1076 int length = Ustrlen(text) + 1;
1077 log_write(0, LOG_MAIN, "%s", text);
1078 logged = store_malloc(sizeof(string_item) + length);
1079 logged->text = (uschar *)logged + sizeof(string_item);
1080 memcpy(logged->text, text, length);
1081 logged->next = acl_warn_logged;
1082 acl_warn_logged = logged;
1086 /* If there's no user message, we are done. */
1088 if (user_message == NULL) return;
1090 /* If this isn't a message ACL, we can't do anything with a user message.
1093 if (where > ACL_WHERE_NOTSMTP)
1095 log_write(0, LOG_MAIN|LOG_PANIC, "ACL \"warn\" with \"message\" setting "
1096 "found in a non-message (%s) ACL: cannot specify header lines here: "
1097 "message ignored", acl_wherenames[where]);
1101 /* The code for setting up header lines is now abstracted into a separate
1102 function so that it can be used for the add_header modifier as well. */
1104 setup_header(user_message);
1109 /*************************************************
1110 * Verify and check reverse DNS *
1111 *************************************************/
1113 /* Called from acl_verify() below. We look up the host name(s) of the client IP
1114 address if this has not yet been done. The host_name_lookup() function checks
1115 that one of these names resolves to an address list that contains the client IP
1116 address, so we don't actually have to do the check here.
1119 user_msgptr pointer for user message
1120 log_msgptr pointer for log message
1122 Returns: OK verification condition succeeded
1123 FAIL verification failed
1124 DEFER there was a problem verifying
1128 acl_verify_reverse(uschar **user_msgptr, uschar **log_msgptr)
1132 user_msgptr = user_msgptr; /* stop compiler warning */
1134 /* Previous success */
1136 if (sender_host_name != NULL) return OK;
1138 /* Previous failure */
1140 if (host_lookup_failed)
1142 *log_msgptr = string_sprintf("host lookup failed%s", host_lookup_msg);
1146 /* Need to do a lookup */
1149 debug_printf("looking up host name to force name/address consistency check\n");
1151 if ((rc = host_name_lookup()) != OK)
1153 *log_msgptr = (rc == DEFER)?
1154 US"host lookup deferred for reverse lookup check"
1156 string_sprintf("host lookup failed for reverse lookup check%s",
1158 return rc; /* DEFER or FAIL */
1161 host_build_sender_fullhost();
1167 /*************************************************
1168 * Check client IP address matches CSA target *
1169 *************************************************/
1171 /* Called from acl_verify_csa() below. This routine scans a section of a DNS
1172 response for address records belonging to the CSA target hostname. The section
1173 is specified by the reset argument, either RESET_ADDITIONAL or RESET_ANSWERS.
1174 If one of the addresses matches the client's IP address, then the client is
1175 authorized by CSA. If there are target IP addresses but none of them match
1176 then the client is using an unauthorized IP address. If there are no target IP
1177 addresses then the client cannot be using an authorized IP address. (This is
1178 an odd configuration - why didn't the SRV record have a weight of 1 instead?)
1181 dnsa the DNS answer block
1182 dnss a DNS scan block for us to use
1183 reset option specifing what portion to scan, as described above
1184 target the target hostname to use for matching RR names
1186 Returns: CSA_OK successfully authorized
1187 CSA_FAIL_MISMATCH addresses found but none matched
1188 CSA_FAIL_NOADDR no target addresses found
1192 acl_verify_csa_address(dns_answer *dnsa, dns_scan *dnss, int reset,
1198 BOOL target_found = FALSE;
1200 for (rr = dns_next_rr(dnsa, dnss, reset);
1202 rr = dns_next_rr(dnsa, dnss, RESET_NEXT))
1204 /* Check this is an address RR for the target hostname. */
1208 && rr->type != T_AAAA
1215 if (strcmpic(target, rr->name) != 0) continue;
1217 target_found = TRUE;
1219 /* Turn the target address RR into a list of textual IP addresses and scan
1220 the list. There may be more than one if it is an A6 RR. */
1222 for (da = dns_address_from_rr(dnsa, rr); da != NULL; da = da->next)
1224 /* If the client IP address matches the target IP address, it's good! */
1226 DEBUG(D_acl) debug_printf("CSA target address is %s\n", da->address);
1228 if (strcmpic(sender_host_address, da->address) == 0) return CSA_OK;
1232 /* If we found some target addresses but none of them matched, the client is
1233 using an unauthorized IP address, otherwise the target has no authorized IP
1236 if (target_found) return CSA_FAIL_MISMATCH;
1237 else return CSA_FAIL_NOADDR;
1242 /*************************************************
1243 * Verify Client SMTP Authorization *
1244 *************************************************/
1246 /* Called from acl_verify() below. This routine calls dns_lookup_special()
1247 to find the CSA SRV record corresponding to the domain argument, or
1248 $sender_helo_name if no argument is provided. It then checks that the
1249 client is authorized, and that its IP address corresponds to the SRV
1250 target's address by calling acl_verify_csa_address() above. The address
1251 should have been returned in the DNS response's ADDITIONAL section, but if
1252 not we perform another DNS lookup to get it.
1255 domain pointer to optional parameter following verify = csa
1257 Returns: CSA_UNKNOWN no valid CSA record found
1258 CSA_OK successfully authorized
1259 CSA_FAIL_* client is definitely not authorized
1260 CSA_DEFER_* there was a DNS problem
1264 acl_verify_csa(uschar *domain)
1268 int priority, weight, port;
1275 /* Work out the domain we are using for the CSA lookup. The default is the
1276 client's HELO domain. If the client has not said HELO, use its IP address
1277 instead. If it's a local client (exim -bs), CSA isn't applicable. */
1279 while (isspace(*domain) && *domain != '\0') ++domain;
1280 if (*domain == '\0') domain = sender_helo_name;
1281 if (domain == NULL) domain = sender_host_address;
1282 if (sender_host_address == NULL) return CSA_UNKNOWN;
1284 /* If we have an address literal, strip off the framing ready for turning it
1285 into a domain. The framing consists of matched square brackets possibly
1286 containing a keyword and a colon before the actual IP address. */
1288 if (domain[0] == '[')
1290 uschar *start = Ustrchr(domain, ':');
1291 if (start == NULL) start = domain;
1292 domain = string_copyn(start + 1, Ustrlen(start) - 2);
1295 /* Turn domains that look like bare IP addresses into domains in the reverse
1296 DNS. This code also deals with address literals and $sender_host_address. It's
1297 not quite kosher to treat bare domains such as EHLO 192.0.2.57 the same as
1298 address literals, but it's probably the most friendly thing to do. This is an
1299 extension to CSA, so we allow it to be turned off for proper conformance. */
1301 if (string_is_ip_address(domain, NULL) != 0)
1303 if (!dns_csa_use_reverse) return CSA_UNKNOWN;
1304 dns_build_reverse(domain, target);
1308 /* Find out if we've already done the CSA check for this domain. If we have,
1309 return the same result again. Otherwise build a new cached result structure
1310 for this domain. The name is filled in now, and the value is filled in when
1311 we return from this function. */
1313 t = tree_search(csa_cache, domain);
1314 if (t != NULL) return t->data.val;
1316 t = store_get_perm(sizeof(tree_node) + Ustrlen(domain));
1317 Ustrcpy(t->name, domain);
1318 (void)tree_insertnode(&csa_cache, t);
1320 /* Now we are ready to do the actual DNS lookup(s). */
1323 switch (dns_special_lookup(&dnsa, domain, T_CSA, &found))
1325 /* If something bad happened (most commonly DNS_AGAIN), defer. */
1328 return t->data.val = CSA_DEFER_SRV;
1330 /* If we found nothing, the client's authorization is unknown. */
1334 return t->data.val = CSA_UNKNOWN;
1336 /* We got something! Go on to look at the reply in more detail. */
1342 /* Scan the reply for well-formed CSA SRV records. */
1344 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
1346 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
1348 if (rr->type != T_SRV) continue;
1350 /* Extract the numerical SRV fields (p is incremented) */
1353 GETSHORT(priority, p);
1354 GETSHORT(weight, p);
1358 debug_printf("CSA priority=%d weight=%d port=%d\n", priority, weight, port);
1360 /* Check the CSA version number */
1362 if (priority != 1) continue;
1364 /* If the domain does not have a CSA SRV record of its own (i.e. the domain
1365 found by dns_special_lookup() is a parent of the one we asked for), we check
1366 the subdomain assertions in the port field. At the moment there's only one
1367 assertion: legitimate SMTP clients are all explicitly authorized with CSA
1368 SRV records of their own. */
1370 if (found != domain)
1373 return t->data.val = CSA_FAIL_EXPLICIT;
1375 return t->data.val = CSA_UNKNOWN;
1378 /* This CSA SRV record refers directly to our domain, so we check the value
1379 in the weight field to work out the domain's authorization. 0 and 1 are
1380 unauthorized; 3 means the client is authorized but we can't check the IP
1381 address in order to authenticate it, so we treat it as unknown; values
1382 greater than 3 are undefined. */
1384 if (weight < 2) return t->data.val = CSA_FAIL_DOMAIN;
1386 if (weight > 2) continue;
1388 /* Weight == 2, which means the domain is authorized. We must check that the
1389 client's IP address is listed as one of the SRV target addresses. Save the
1390 target hostname then break to scan the additional data for its addresses. */
1392 (void)dn_expand(dnsa.answer, dnsa.answer + dnsa.answerlen, p,
1393 (DN_EXPAND_ARG4_TYPE)target, sizeof(target));
1395 DEBUG(D_acl) debug_printf("CSA target is %s\n", target);
1400 /* If we didn't break the loop then no appropriate records were found. */
1402 if (rr == NULL) return t->data.val = CSA_UNKNOWN;
1404 /* Do not check addresses if the target is ".", in accordance with RFC 2782.
1405 A target of "." indicates there are no valid addresses, so the client cannot
1406 be authorized. (This is an odd configuration because weight=2 target=. is
1407 equivalent to weight=1, but we check for it in order to keep load off the
1408 root name servers.) Note that dn_expand() turns "." into "". */
1410 if (Ustrcmp(target, "") == 0) return t->data.val = CSA_FAIL_NOADDR;
1412 /* Scan the additional section of the CSA SRV reply for addresses belonging
1413 to the target. If the name server didn't return any additional data (e.g.
1414 because it does not fully support SRV records), we need to do another lookup
1415 to obtain the target addresses; otherwise we have a definitive result. */
1417 rc = acl_verify_csa_address(&dnsa, &dnss, RESET_ADDITIONAL, target);
1418 if (rc != CSA_FAIL_NOADDR) return t->data.val = rc;
1420 /* The DNS lookup type corresponds to the IP version used by the client. */
1423 if (Ustrchr(sender_host_address, ':') != NULL)
1426 #endif /* HAVE_IPV6 */
1430 #if HAVE_IPV6 && defined(SUPPORT_A6)
1434 switch (dns_lookup(&dnsa, target, type, NULL))
1436 /* If something bad happened (most commonly DNS_AGAIN), defer. */
1439 return t->data.val = CSA_DEFER_ADDR;
1441 /* If the query succeeded, scan the addresses and return the result. */
1444 rc = acl_verify_csa_address(&dnsa, &dnss, RESET_ANSWERS, target);
1445 if (rc != CSA_FAIL_NOADDR) return t->data.val = rc;
1446 /* else fall through */
1448 /* If the target has no IP addresses, the client cannot have an authorized
1449 IP address. However, if the target site uses A6 records (not AAAA records)
1450 we have to do yet another lookup in order to check them. */
1455 #if HAVE_IPV6 && defined(SUPPORT_A6)
1456 if (type == T_AAAA) { type = T_A6; goto DNS_LOOKUP_AGAIN; }
1459 return t->data.val = CSA_FAIL_NOADDR;
1465 /*************************************************
1466 * Handle verification (address & other) *
1467 *************************************************/
1469 /* This function implements the "verify" condition. It is called when
1470 encountered in any ACL, because some tests are almost always permitted. Some
1471 just don't make sense, and always fail (for example, an attempt to test a host
1472 lookup for a non-TCP/IP message). Others are restricted to certain ACLs.
1475 where where called from
1476 addr the recipient address that the ACL is handling, or NULL
1477 arg the argument of "verify"
1478 user_msgptr pointer for user message
1479 log_msgptr pointer for log message
1480 basic_errno where to put verify errno
1482 Returns: OK verification condition succeeded
1483 FAIL verification failed
1484 DEFER there was a problem verifying
1489 acl_verify(int where, address_item *addr, uschar *arg,
1490 uschar **user_msgptr, uschar **log_msgptr, int *basic_errno)
1494 int callout_overall = -1;
1495 int callout_connect = -1;
1496 int verify_options = 0;
1498 BOOL verify_header_sender = FALSE;
1499 BOOL defer_ok = FALSE;
1500 BOOL callout_defer_ok = FALSE;
1501 BOOL no_details = FALSE;
1502 BOOL success_on_redirect = FALSE;
1503 address_item *sender_vaddr = NULL;
1504 uschar *verify_sender_address = NULL;
1505 uschar *pm_mailfrom = NULL;
1506 uschar *se_mailfrom = NULL;
1508 /* Some of the verify items have slash-separated options; some do not. Diagnose
1509 an error if options are given for items that don't expect them. This code has
1510 now got very message. Refactoring to use a table would be a good idea one day.
1513 uschar *slash = Ustrchr(arg, '/');
1515 uschar *ss = string_nextinlist(&list, &sep, big_buffer, big_buffer_size);
1517 if (ss == NULL) goto BAD_VERIFY;
1519 /* Handle name/address consistency verification in a separate function. */
1521 if (strcmpic(ss, US"reverse_host_lookup") == 0)
1523 if (slash != NULL) goto NO_OPTIONS;
1524 if (sender_host_address == NULL) return OK;
1525 return acl_verify_reverse(user_msgptr, log_msgptr);
1528 /* TLS certificate verification is done at STARTTLS time; here we just
1529 test whether it was successful or not. (This is for optional verification; for
1530 mandatory verification, the connection doesn't last this long.) */
1532 if (strcmpic(ss, US"certificate") == 0)
1534 if (slash != NULL) goto NO_OPTIONS;
1535 if (tls_certificate_verified) return OK;
1536 *user_msgptr = US"no verified certificate";
1540 /* We can test the result of optional HELO verification that might have
1541 occurred earlier. If not, we can attempt the verification now. */
1543 if (strcmpic(ss, US"helo") == 0)
1545 if (slash != NULL) goto NO_OPTIONS;
1546 if (!helo_verified && !helo_verify_failed) smtp_verify_helo();
1547 return helo_verified? OK : FAIL;
1550 /* Do Client SMTP Authorization checks in a separate function, and turn the
1551 result code into user-friendly strings. */
1553 if (strcmpic(ss, US"csa") == 0)
1555 rc = acl_verify_csa(list);
1556 *log_msgptr = *user_msgptr = string_sprintf("client SMTP authorization %s",
1557 csa_reason_string[rc]);
1558 csa_status = csa_status_string[rc];
1559 DEBUG(D_acl) debug_printf("CSA result %s\n", csa_status);
1560 return csa_return_code[rc];
1563 /* Check that all relevant header lines have the correct syntax. If there is
1564 a syntax error, we return details of the error to the sender if configured to
1565 send out full details. (But a "message" setting on the ACL can override, as
1568 if (strcmpic(ss, US"header_syntax") == 0)
1570 if (slash != NULL) goto NO_OPTIONS;
1571 if (where != ACL_WHERE_DATA && where != ACL_WHERE_NOTSMTP) goto WRONG_ACL;
1572 rc = verify_check_headers(log_msgptr);
1573 if (rc != OK && smtp_return_error_details && *log_msgptr != NULL)
1574 *user_msgptr = string_sprintf("Rejected after DATA: %s", *log_msgptr);
1578 /* Check that no recipient of this message is "blind", that is, every envelope
1579 recipient must be mentioned in either To: or Cc:. */
1581 if (strcmpic(ss, US"not_blind") == 0)
1583 if (slash != NULL) goto NO_OPTIONS;
1584 if (where != ACL_WHERE_DATA && where != ACL_WHERE_NOTSMTP) goto WRONG_ACL;
1585 rc = verify_check_notblind();
1588 *log_msgptr = string_sprintf("bcc recipient detected");
1589 if (smtp_return_error_details)
1590 *user_msgptr = string_sprintf("Rejected after DATA: %s", *log_msgptr);
1595 /* The remaining verification tests check recipient and sender addresses,
1596 either from the envelope or from the header. There are a number of
1597 slash-separated options that are common to all of them. */
1600 /* Check that there is at least one verifiable sender address in the relevant
1601 header lines. This can be followed by callout and defer options, just like
1602 sender and recipient. */
1604 if (strcmpic(ss, US"header_sender") == 0)
1606 if (where != ACL_WHERE_DATA && where != ACL_WHERE_NOTSMTP) goto WRONG_ACL;
1607 verify_header_sender = TRUE;
1610 /* Otherwise, first item in verify argument must be "sender" or "recipient".
1611 In the case of a sender, this can optionally be followed by an address to use
1612 in place of the actual sender (rare special-case requirement). */
1614 else if (strncmpic(ss, US"sender", 6) == 0)
1617 if (where > ACL_WHERE_NOTSMTP)
1619 *log_msgptr = string_sprintf("cannot verify sender in ACL for %s "
1620 "(only possible for MAIL, RCPT, PREDATA, or DATA)",
1621 acl_wherenames[where]);
1625 verify_sender_address = sender_address;
1628 while (isspace(*s)) s++;
1629 if (*s++ != '=') goto BAD_VERIFY;
1630 while (isspace(*s)) s++;
1631 verify_sender_address = string_copy(s);
1636 if (strcmpic(ss, US"recipient") != 0) goto BAD_VERIFY;
1639 *log_msgptr = string_sprintf("cannot verify recipient in ACL for %s "
1640 "(only possible for RCPT)", acl_wherenames[where]);
1645 /* Remaining items are optional; they apply to sender and recipient
1646 verification, including "header sender" verification. */
1648 while ((ss = string_nextinlist(&list, &sep, big_buffer, big_buffer_size))
1651 if (strcmpic(ss, US"defer_ok") == 0) defer_ok = TRUE;
1652 else if (strcmpic(ss, US"no_details") == 0) no_details = TRUE;
1653 else if (strcmpic(ss, US"success_on_redirect") == 0) success_on_redirect = TRUE;
1655 /* These two old options are left for backwards compatibility */
1657 else if (strcmpic(ss, US"callout_defer_ok") == 0)
1659 callout_defer_ok = TRUE;
1660 if (callout == -1) callout = CALLOUT_TIMEOUT_DEFAULT;
1663 else if (strcmpic(ss, US"check_postmaster") == 0)
1666 if (callout == -1) callout = CALLOUT_TIMEOUT_DEFAULT;
1669 /* The callout option has a number of sub-options, comma separated */
1671 else if (strncmpic(ss, US"callout", 7) == 0)
1673 callout = CALLOUT_TIMEOUT_DEFAULT;
1677 while (isspace(*ss)) ss++;
1683 while (isspace(*ss)) ss++;
1685 /* This callout option handling code has become a mess as new options
1686 have been added in an ad hoc manner. It should be tidied up into some
1687 kind of table-driven thing. */
1689 while ((opt = string_nextinlist(&ss, &optsep, buffer, sizeof(buffer)))
1692 if (strcmpic(opt, US"defer_ok") == 0) callout_defer_ok = TRUE;
1693 else if (strcmpic(opt, US"no_cache") == 0)
1694 verify_options |= vopt_callout_no_cache;
1695 else if (strcmpic(opt, US"random") == 0)
1696 verify_options |= vopt_callout_random;
1697 else if (strcmpic(opt, US"use_sender") == 0)
1698 verify_options |= vopt_callout_recipsender;
1699 else if (strcmpic(opt, US"use_postmaster") == 0)
1700 verify_options |= vopt_callout_recippmaster;
1701 else if (strcmpic(opt, US"postmaster") == 0) pm_mailfrom = US"";
1702 else if (strcmpic(opt, US"fullpostmaster") == 0)
1705 verify_options |= vopt_callout_fullpm;
1708 else if (strncmpic(opt, US"mailfrom", 8) == 0)
1710 if (!verify_header_sender)
1712 *log_msgptr = string_sprintf("\"mailfrom\" is allowed as a "
1713 "callout option only for verify=header_sender (detected in ACL "
1714 "condition \"%s\")", arg);
1718 while (isspace(*opt)) opt++;
1721 *log_msgptr = string_sprintf("'=' expected after "
1722 "\"mailfrom\" in ACL condition \"%s\"", arg);
1725 while (isspace(*opt)) opt++;
1726 se_mailfrom = string_copy(opt);
1729 else if (strncmpic(opt, US"postmaster_mailfrom", 19) == 0)
1732 while (isspace(*opt)) opt++;
1735 *log_msgptr = string_sprintf("'=' expected after "
1736 "\"postmaster_mailfrom\" in ACL condition \"%s\"", arg);
1739 while (isspace(*opt)) opt++;
1740 pm_mailfrom = string_copy(opt);
1743 else if (strncmpic(opt, US"maxwait", 7) == 0)
1746 while (isspace(*opt)) opt++;
1749 *log_msgptr = string_sprintf("'=' expected after \"maxwait\" in "
1750 "ACL condition \"%s\"", arg);
1753 while (isspace(*opt)) opt++;
1754 callout_overall = readconf_readtime(opt, 0, FALSE);
1755 if (callout_overall < 0)
1757 *log_msgptr = string_sprintf("bad time value in ACL condition "
1758 "\"verify %s\"", arg);
1762 else if (strncmpic(opt, US"connect", 7) == 0)
1765 while (isspace(*opt)) opt++;
1768 *log_msgptr = string_sprintf("'=' expected after "
1769 "\"callout_overaall\" in ACL condition \"%s\"", arg);
1772 while (isspace(*opt)) opt++;
1773 callout_connect = readconf_readtime(opt, 0, FALSE);
1774 if (callout_connect < 0)
1776 *log_msgptr = string_sprintf("bad time value in ACL condition "
1777 "\"verify %s\"", arg);
1781 else /* Plain time is callout connect/command timeout */
1783 callout = readconf_readtime(opt, 0, FALSE);
1786 *log_msgptr = string_sprintf("bad time value in ACL condition "
1787 "\"verify %s\"", arg);
1795 *log_msgptr = string_sprintf("'=' expected after \"callout\" in "
1796 "ACL condition \"%s\"", arg);
1802 /* Option not recognized */
1806 *log_msgptr = string_sprintf("unknown option \"%s\" in ACL "
1807 "condition \"verify %s\"", ss, arg);
1812 if ((verify_options & (vopt_callout_recipsender|vopt_callout_recippmaster)) ==
1813 (vopt_callout_recipsender|vopt_callout_recippmaster))
1815 *log_msgptr = US"only one of use_sender and use_postmaster can be set "
1816 "for a recipient callout";
1820 /* Handle sender-in-header verification. Default the user message to the log
1821 message if giving out verification details. */
1823 if (verify_header_sender)
1826 rc = verify_check_header_address(user_msgptr, log_msgptr, callout,
1827 callout_overall, callout_connect, se_mailfrom, pm_mailfrom, verify_options,
1831 *basic_errno = verrno;
1832 if (smtp_return_error_details)
1834 if (*user_msgptr == NULL && *log_msgptr != NULL)
1835 *user_msgptr = string_sprintf("Rejected after DATA: %s", *log_msgptr);
1836 if (rc == DEFER) acl_temp_details = TRUE;
1841 /* Handle a sender address. The default is to verify *the* sender address, but
1842 optionally a different address can be given, for special requirements. If the
1843 address is empty, we are dealing with a bounce message that has no sender, so
1844 we cannot do any checking. If the real sender address gets rewritten during
1845 verification (e.g. DNS widening), set the flag to stop it being rewritten again
1846 during message reception.
1848 A list of verified "sender" addresses is kept to try to avoid doing to much
1849 work repetitively when there are multiple recipients in a message and they all
1850 require sender verification. However, when callouts are involved, it gets too
1851 complicated because different recipients may require different callout options.
1852 Therefore, we always do a full sender verify when any kind of callout is
1853 specified. Caching elsewhere, for instance in the DNS resolver and in the
1854 callout handling, should ensure that this is not terribly inefficient. */
1856 else if (verify_sender_address != NULL)
1858 if ((verify_options & (vopt_callout_recipsender|vopt_callout_recippmaster))
1861 *log_msgptr = US"use_sender or use_postmaster cannot be used for a "
1862 "sender verify callout";
1866 sender_vaddr = verify_checked_sender(verify_sender_address);
1867 if (sender_vaddr != NULL && /* Previously checked */
1868 callout <= 0) /* No callout needed this time */
1870 /* If the "routed" flag is set, it means that routing worked before, so
1871 this check can give OK (the saved return code value, if set, belongs to a
1872 callout that was done previously). If the "routed" flag is not set, routing
1873 must have failed, so we use the saved return code. */
1875 if (testflag(sender_vaddr, af_verify_routed)) rc = OK; else
1877 rc = sender_vaddr->special_action;
1878 *basic_errno = sender_vaddr->basic_errno;
1880 HDEBUG(D_acl) debug_printf("using cached sender verify result\n");
1883 /* Do a new verification, and cache the result. The cache is used to avoid
1884 verifying the sender multiple times for multiple RCPTs when callouts are not
1885 specified (see comments above).
1887 The cache is also used on failure to give details in response to the first
1888 RCPT that gets bounced for this reason. However, this can be suppressed by
1889 the no_details option, which sets the flag that says "this detail has already
1890 been sent". The cache normally contains just one address, but there may be
1891 more in esoteric circumstances. */
1896 uschar *save_address_data = deliver_address_data;
1898 sender_vaddr = deliver_make_addr(verify_sender_address, TRUE);
1899 if (no_details) setflag(sender_vaddr, af_sverify_told);
1900 if (verify_sender_address[0] != 0)
1902 /* If this is the real sender address, save the unrewritten version
1903 for use later in receive. Otherwise, set a flag so that rewriting the
1904 sender in verify_address() does not update sender_address. */
1906 if (verify_sender_address == sender_address)
1907 sender_address_unrewritten = sender_address;
1909 verify_options |= vopt_fake_sender;
1911 if (success_on_redirect)
1912 verify_options |= vopt_success_on_redirect;
1914 /* The recipient, qualify, and expn options are never set in
1917 rc = verify_address(sender_vaddr, NULL, verify_options, callout,
1918 callout_overall, callout_connect, se_mailfrom, pm_mailfrom, &routed);
1920 HDEBUG(D_acl) debug_printf("----------- end verify ------------\n");
1924 if (Ustrcmp(sender_vaddr->address, verify_sender_address) != 0)
1926 DEBUG(D_acl) debug_printf("sender %s verified ok as %s\n",
1927 verify_sender_address, sender_vaddr->address);
1931 DEBUG(D_acl) debug_printf("sender %s verified ok\n",
1932 verify_sender_address);
1935 else *basic_errno = sender_vaddr->basic_errno;
1937 else rc = OK; /* Null sender */
1939 /* Cache the result code */
1941 if (routed) setflag(sender_vaddr, af_verify_routed);
1942 if (callout > 0) setflag(sender_vaddr, af_verify_callout);
1943 sender_vaddr->special_action = rc;
1944 sender_vaddr->next = sender_verified_list;
1945 sender_verified_list = sender_vaddr;
1947 /* Restore the recipient address data, which might have been clobbered by
1948 the sender verification. */
1950 deliver_address_data = save_address_data;
1953 /* Put the sender address_data value into $sender_address_data */
1955 sender_address_data = sender_vaddr->p.address_data;
1958 /* A recipient address just gets a straightforward verify; again we must handle
1959 the DEFER overrides. */
1965 if (success_on_redirect)
1966 verify_options |= vopt_success_on_redirect;
1968 /* We must use a copy of the address for verification, because it might
1972 rc = verify_address(&addr2, NULL, verify_options|vopt_is_recipient, callout,
1973 callout_overall, callout_connect, se_mailfrom, pm_mailfrom, NULL);
1974 HDEBUG(D_acl) debug_printf("----------- end verify ------------\n");
1976 *basic_errno = addr2.basic_errno;
1977 *log_msgptr = addr2.message;
1978 *user_msgptr = (addr2.user_message != NULL)?
1979 addr2.user_message : addr2.message;
1981 /* Allow details for temporary error if the address is so flagged. */
1982 if (testflag((&addr2), af_pass_message)) acl_temp_details = TRUE;
1984 /* Make $address_data visible */
1985 deliver_address_data = addr2.p.address_data;
1988 /* We have a result from the relevant test. Handle defer overrides first. */
1990 if (rc == DEFER && (defer_ok ||
1991 (callout_defer_ok && *basic_errno == ERRNO_CALLOUTDEFER)))
1993 HDEBUG(D_acl) debug_printf("verify defer overridden by %s\n",
1994 defer_ok? "defer_ok" : "callout_defer_ok");
1998 /* If we've failed a sender, set up a recipient message, and point
1999 sender_verified_failed to the address item that actually failed. */
2001 if (rc != OK && verify_sender_address != NULL)
2005 *log_msgptr = *user_msgptr = US"Sender verify failed";
2007 else if (*basic_errno != ERRNO_CALLOUTDEFER)
2009 *log_msgptr = *user_msgptr = US"Could not complete sender verify";
2013 *log_msgptr = US"Could not complete sender verify callout";
2014 *user_msgptr = smtp_return_error_details? sender_vaddr->user_message :
2018 sender_verified_failed = sender_vaddr;
2021 /* Verifying an address messes up the values of $domain and $local_part,
2022 so reset them before returning if this is a RCPT ACL. */
2026 deliver_domain = addr->domain;
2027 deliver_localpart = addr->local_part;
2031 /* Syntax errors in the verify argument come here. */
2034 *log_msgptr = string_sprintf("expected \"sender[=address]\", \"recipient\", "
2035 "\"helo\", \"header_syntax\", \"header_sender\" or "
2036 "\"reverse_host_lookup\" at start of ACL condition "
2037 "\"verify %s\"", arg);
2040 /* Options supplied when not allowed come here */
2043 *log_msgptr = string_sprintf("unexpected '/' found in \"%s\" "
2044 "(this verify item has no options)", arg);
2047 /* Calls in the wrong ACL come here */
2050 *log_msgptr = string_sprintf("cannot check header contents in ACL for %s "
2051 "(only possible in ACL for DATA)", acl_wherenames[where]);
2058 /*************************************************
2059 * Check argument for control= modifier *
2060 *************************************************/
2062 /* Called from acl_check_condition() below
2065 arg the argument string for control=
2066 pptr set to point to the terminating character
2067 where which ACL we are in
2068 log_msgptr for error messages
2070 Returns: CONTROL_xxx value
2074 decode_control(uschar *arg, uschar **pptr, int where, uschar **log_msgptr)
2079 for (d = controls_list;
2080 d < controls_list + sizeof(controls_list)/sizeof(control_def);
2083 len = Ustrlen(d->name);
2084 if (Ustrncmp(d->name, arg, len) == 0) break;
2087 if (d >= controls_list + sizeof(controls_list)/sizeof(control_def) ||
2088 (arg[len] != 0 && (!d->has_option || arg[len] != '/')))
2090 *log_msgptr = string_sprintf("syntax error in \"control=%s\"", arg);
2091 return CONTROL_ERROR;
2101 /*************************************************
2102 * Return a ratelimit error *
2103 *************************************************/
2105 /* Called from acl_ratelimit() below
2108 log_msgptr for error messages
2109 format format string
2110 ... supplementary arguments
2111 ss ratelimit option name
2112 where ACL_WHERE_xxxx indicating which ACL this is
2118 ratelimit_error(uschar **log_msgptr, const char *format, ...)
2121 uschar buffer[STRING_SPRINTF_BUFFER_SIZE];
2122 va_start(ap, format);
2123 if (!string_vformat(buffer, sizeof(buffer), format, ap))
2124 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2125 "string_sprintf expansion was longer than %d", sizeof(buffer));
2127 *log_msgptr = string_sprintf(
2128 "error in arguments to \"ratelimit\" condition: %s", buffer);
2135 /*************************************************
2136 * Handle rate limiting *
2137 *************************************************/
2139 /* Called by acl_check_condition() below to calculate the result
2140 of the ACL ratelimit condition.
2142 Note that the return value might be slightly unexpected: if the
2143 sender's rate is above the limit then the result is OK. This is
2144 similar to the dnslists condition, and is so that you can write
2145 ACL clauses like: defer ratelimit = 15 / 1h
2148 arg the option string for ratelimit=
2149 where ACL_WHERE_xxxx indicating which ACL this is
2150 log_msgptr for error messages
2152 Returns: OK - Sender's rate is above limit
2153 FAIL - Sender's rate is below limit
2154 DEFER - Problem opening ratelimit database
2155 ERROR - Syntax error in options.
2159 acl_ratelimit(uschar *arg, int where, uschar **log_msgptr)
2161 double limit, period, count;
2164 uschar *unique = NULL;
2166 BOOL leaky = FALSE, strict = FALSE, readonly = FALSE;
2167 BOOL noupdate = FALSE, badacl = FALSE;
2168 int mode = RATE_PER_WHAT;
2170 tree_node **anchor, *t;
2171 open_db dbblock, *dbm;
2173 dbdata_ratelimit *dbd;
2174 dbdata_ratelimit_unique *dbdb;
2177 /* Parse the first two options and record their values in expansion
2178 variables. These variables allow the configuration to have informative
2179 error messages based on rate limits obtained from a table lookup. */
2181 /* First is the maximum number of messages per period / maximum burst
2182 size, which must be greater than or equal to zero. Zero is useful for
2183 rate measurement as opposed to rate limiting. */
2185 sender_rate_limit = string_nextinlist(&arg, &sep, NULL, 0);
2186 if (sender_rate_limit == NULL)
2190 limit = Ustrtod(sender_rate_limit, &ss);
2191 if (tolower(*ss) == 'k') { limit *= 1024.0; ss++; }
2192 else if (tolower(*ss) == 'm') { limit *= 1024.0*1024.0; ss++; }
2193 else if (tolower(*ss) == 'g') { limit *= 1024.0*1024.0*1024.0; ss++; }
2195 if (limit < 0.0 || *ss != '\0')
2196 return ratelimit_error(log_msgptr,
2197 "\"%s\" is not a positive number", sender_rate_limit);
2199 /* Second is the rate measurement period / exponential smoothing time
2200 constant. This must be strictly greater than zero, because zero leads to
2201 run-time division errors. */
2203 sender_rate_period = string_nextinlist(&arg, &sep, NULL, 0);
2204 if (sender_rate_period == NULL) period = -1.0;
2205 else period = readconf_readtime(sender_rate_period, 0, FALSE);
2207 return ratelimit_error(log_msgptr,
2208 "\"%s\" is not a time value", sender_rate_period);
2210 /* By default we are counting one of something, but the per_rcpt,
2211 per_byte, and count options can change this. */
2215 /* Parse the other options. */
2217 while ((ss = string_nextinlist(&arg, &sep, big_buffer, big_buffer_size))
2220 if (strcmpic(ss, US"leaky") == 0) leaky = TRUE;
2221 else if (strcmpic(ss, US"strict") == 0) strict = TRUE;
2222 else if (strcmpic(ss, US"noupdate") == 0) noupdate = TRUE;
2223 else if (strcmpic(ss, US"readonly") == 0) readonly = TRUE;
2224 else if (strcmpic(ss, US"per_cmd") == 0) RATE_SET(mode, PER_CMD);
2225 else if (strcmpic(ss, US"per_conn") == 0)
2227 RATE_SET(mode, PER_CONN);
2228 if (where == ACL_WHERE_NOTSMTP || where == ACL_WHERE_NOTSMTP_START)
2231 else if (strcmpic(ss, US"per_mail") == 0)
2233 RATE_SET(mode, PER_MAIL);
2234 if (where > ACL_WHERE_NOTSMTP) badacl = TRUE;
2236 else if (strcmpic(ss, US"per_rcpt") == 0)
2238 /* If we are running in the RCPT ACL, then we'll count the recipients
2239 one by one, but if we are running when we have accumulated the whole
2240 list then we'll add them all in one batch. */
2241 if (where == ACL_WHERE_RCPT)
2242 RATE_SET(mode, PER_RCPT);
2243 else if (where >= ACL_WHERE_PREDATA && where <= ACL_WHERE_NOTSMTP)
2244 RATE_SET(mode, PER_ALLRCPTS), count = (double)recipients_count;
2245 else if (where == ACL_WHERE_MAIL || where > ACL_WHERE_NOTSMTP)
2246 RATE_SET(mode, PER_RCPT), badacl = TRUE;
2248 else if (strcmpic(ss, US"per_byte") == 0)
2250 /* If we have not yet received the message data and there was no SIZE
2251 declaration on the MAIL comand, then it's safe to just use a value of
2252 zero and let the recorded rate decay as if nothing happened. */
2253 RATE_SET(mode, PER_MAIL);
2254 if (where > ACL_WHERE_NOTSMTP) badacl = TRUE;
2255 else count = message_size < 0 ? 0.0 : (double)message_size;
2257 else if (strcmpic(ss, US"per_addr") == 0)
2259 RATE_SET(mode, PER_RCPT);
2260 if (where != ACL_WHERE_RCPT) badacl = TRUE, unique = "*";
2261 else unique = string_sprintf("%s@%s", deliver_localpart, deliver_domain);
2263 else if (strncmpic(ss, US"count=", 6) == 0)
2266 count = Ustrtod(ss+6, &e);
2267 if (count < 0.0 || *e != '\0')
2268 return ratelimit_error(log_msgptr,
2269 "\"%s\" is not a positive number", ss);
2271 else if (strncmpic(ss, US"unique=", 7) == 0)
2272 unique = string_copy(ss + 7);
2273 else if (key == NULL)
2274 key = string_copy(ss);
2276 key = string_sprintf("%s/%s", key, ss);
2279 /* Sanity check. When the badacl flag is set the update mode must either
2280 be readonly (which is the default if it is omitted) or, for backwards
2281 compatibility, a combination of noupdate and strict or leaky. */
2283 if (mode == RATE_PER_CLASH)
2284 return ratelimit_error(log_msgptr, "conflicting per_* options");
2285 if (leaky + strict + readonly > 1)
2286 return ratelimit_error(log_msgptr, "conflicting update modes");
2287 if (badacl && (leaky || strict) && !noupdate)
2288 return ratelimit_error(log_msgptr,
2289 "\"%s\" must not have /leaky or /strict option in %s ACL",
2290 ratelimit_option_string[mode], acl_wherenames[where]);
2292 /* Set the default values of any unset options. In readonly mode we
2293 perform the rate computation without any increment so that its value
2294 decays to eventually allow over-limit senders through. */
2296 if (noupdate) readonly = TRUE, leaky = strict = FALSE;
2297 if (badacl) readonly = TRUE;
2298 if (readonly) count = 0.0;
2299 if (!strict && !readonly) leaky = TRUE;
2300 if (mode == RATE_PER_WHAT) mode = RATE_PER_MAIL;
2302 /* Create the lookup key. If there is no explicit key, use sender_host_address.
2303 If there is no sender_host_address (e.g. -bs or acl_not_smtp) then we simply
2304 omit it. The smoothing constant (sender_rate_period) and the per_xxx options
2305 are added to the key because they alter the meaning of the stored data. */
2308 key = (sender_host_address == NULL)? US"" : sender_host_address;
2310 key = string_sprintf("%s/%s/%s%s",
2312 ratelimit_option_string[mode],
2313 unique == NULL ? "" : "unique/",
2317 debug_printf("ratelimit condition count=%.0f %.1f/%s\n", count, limit, key);
2319 /* See if we have already computed the rate by looking in the relevant tree.
2320 For per-connection rate limiting, store tree nodes and dbdata in the permanent
2321 pool so that they survive across resets. In readonly mode we only remember the
2322 result for the rest of this command in case a later command changes it. After
2323 this bit of logic the code is independent of the per_* mode. */
2325 old_pool = store_pool;
2328 anchor = &ratelimiters_cmd;
2331 anchor = &ratelimiters_conn;
2332 store_pool = POOL_PERM;
2336 case RATE_PER_ALLRCPTS:
2337 anchor = &ratelimiters_mail;
2342 anchor = &ratelimiters_cmd;
2345 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2346 "internal ACL error: unknown ratelimit mode %d", mode);
2350 t = tree_search(*anchor, key);
2354 /* The following few lines duplicate some of the code below. */
2355 rc = (dbd->rate < limit)? FAIL : OK;
2356 store_pool = old_pool;
2357 sender_rate = string_sprintf("%.1f", dbd->rate);
2359 debug_printf("ratelimit found pre-computed rate %s\n", sender_rate);
2363 /* We aren't using a pre-computed rate, so get a previously recorded rate
2364 from the database, which will be updated and written back if required. */
2366 dbm = dbfn_open(US"ratelimit", O_RDWR, &dbblock, TRUE);
2369 store_pool = old_pool;
2371 HDEBUG(D_acl) debug_printf("ratelimit database not available\n");
2372 *log_msgptr = US"ratelimit database not available";
2375 dbdb = dbfn_read_with_length(dbm, key, &dbdb_size);
2378 gettimeofday(&tv, NULL);
2382 /* Locate the basic ratelimit block inside the DB data. */
2383 HDEBUG(D_acl) debug_printf("ratelimit found key in database\n");
2386 /* Forget the old Bloom filter if it is too old, so that we count each
2387 repeating event once per period. We don't simply clear and re-use the old
2388 filter because we want its size to change if the limit changes. Note that
2389 we keep the dbd pointer for copying the rate into the new data block. */
2391 if(unique != NULL && tv.tv_sec > dbdb->bloom_epoch + period)
2393 HDEBUG(D_acl) debug_printf("ratelimit discarding old Bloom filter\n");
2399 if(unique != NULL && dbdb_size < sizeof(*dbdb))
2401 HDEBUG(D_acl) debug_printf("ratelimit discarding undersize Bloom filter\n");
2406 /* Allocate a new data block if the database lookup failed
2407 or the Bloom filter passed its age limit. */
2413 /* No Bloom filter. This basic ratelimit block is initialized below. */
2414 HDEBUG(D_acl) debug_printf("ratelimit creating new rate data block\n");
2415 dbdb_size = sizeof(*dbd);
2416 dbdb = store_get(dbdb_size);
2421 HDEBUG(D_acl) debug_printf("ratelimit creating new Bloom filter\n");
2423 /* See the long comment below for an explanation of the magic number 2.
2424 The filter has a minimum size in case the rate limit is very small;
2425 this is determined by the definition of dbdata_ratelimit_unique. */
2427 extra = (int)limit * 2 - sizeof(dbdb->bloom);
2428 if (extra < 0) extra = 0;
2429 dbdb_size = sizeof(*dbdb) + extra;
2430 dbdb = store_get(dbdb_size);
2431 dbdb->bloom_epoch = tv.tv_sec;
2432 dbdb->bloom_size = sizeof(dbdb->bloom) + extra;
2433 memset(dbdb->bloom, 0, dbdb->bloom_size);
2435 /* Preserve any basic ratelimit data (which is our longer-term memory)
2436 by copying it from the discarded block. */
2446 /* If we are counting unique events, find out if this event is new or not.
2447 If the client repeats the event during the current period then it should be
2448 counted. We skip this code in readonly mode for efficiency, because any
2449 changes to the filter will be discarded and because count is already set to
2452 if (unique != NULL && !readonly)
2454 /* We identify unique events using a Bloom filter. (You can find my
2455 notes on Bloom filters at http://fanf.livejournal.com/81696.html)
2456 With the per_addr option, an "event" is a recipient address, though the
2457 user can use the unique option to define their own events. We only count
2458 an event if we have not seen it before.
2460 We size the filter according to the rate limit, which (in leaky mode)
2461 is the limit on the population of the filter. We allow 16 bits of space
2462 per entry (see the construction code above) and we set (up to) 8 of them
2463 when inserting an element (see the loop below). The probability of a false
2464 positive (an event we have not seen before but which we fail to count) is
2468 allzero = exp(-numhash * pop / size)
2469 = exp(-0.5 * pop / limit)
2470 fpr = pow(1 - allzero, numhash)
2472 For senders at the limit the fpr is 0.06% or 1 in 1700
2473 and for senders at half the limit it is 0.0006% or 1 in 170000
2475 In strict mode the Bloom filter can fill up beyond the normal limit, in
2476 which case the false positive rate will rise. This means that the
2477 measured rate for very fast senders can bogusly drop off after a while.
2479 At twice the limit, the fpr is 2.5% or 1 in 40
2480 At four times the limit, it is 31% or 1 in 3.2
2482 It takes ln(pop/limit) periods for an over-limit burst of pop events to
2483 decay below the limit, and if this is more than one then the Bloom filter
2484 will be discarded before the decay gets that far. The false positive rate
2485 at this threshold is 9.3% or 1 in 10.7. */
2488 unsigned n, hash, hinc;
2492 /* Instead of using eight independent hash values, we combine two values
2493 using the formula h1 + n * h2. This does not harm the Bloom filter's
2494 performance, and means the amount of hash we need is independent of the
2495 number of bits we set in the filter. */
2497 md5_start(&md5info);
2498 md5_end(&md5info, unique, Ustrlen(unique), md5sum);
2499 hash = md5sum[0] | md5sum[1] << 8 | md5sum[2] << 16 | md5sum[3] << 24;
2500 hinc = md5sum[4] | md5sum[5] << 8 | md5sum[6] << 16 | md5sum[7] << 24;
2502 /* Scan the bits corresponding to this event. A zero bit means we have
2503 not seen it before. Ensure all bits are set to record this event. */
2505 HDEBUG(D_acl) debug_printf("ratelimit checking uniqueness of %s\n", unique);
2508 for (n = 0; n < 8; n++, hash += hinc)
2510 int bit = 1 << (hash % 8);
2511 int byte = (hash / 8) % dbdb->bloom_size;
2512 if ((dbdb->bloom[byte] & bit) == 0)
2514 dbdb->bloom[byte] |= bit;
2519 /* If this event has occurred before, do not count it. */
2523 HDEBUG(D_acl) debug_printf("ratelimit event found in Bloom filter\n");
2527 HDEBUG(D_acl) debug_printf("ratelimit event added to Bloom filter\n");
2530 /* If there was no previous ratelimit data block for this key, initialize
2531 the new one, otherwise update the block from the database. The initial rate
2532 is what would be computed by the code below for an infinite interval. */
2536 HDEBUG(D_acl) debug_printf("ratelimit initializing new key's rate data\n");
2538 dbd->time_stamp = tv.tv_sec;
2539 dbd->time_usec = tv.tv_usec;
2544 /* The smoothed rate is computed using an exponentially weighted moving
2545 average adjusted for variable sampling intervals. The standard EWMA for
2546 a fixed sampling interval is: f'(t) = (1 - a) * f(t) + a * f'(t - 1)
2547 where f() is the measured value and f'() is the smoothed value.
2549 Old data decays out of the smoothed value exponentially, such that data n
2550 samples old is multiplied by a^n. The exponential decay time constant p
2551 is defined such that data p samples old is multiplied by 1/e, which means
2552 that a = exp(-1/p). We can maintain the same time constant for a variable
2553 sampling interval i by using a = exp(-i/p).
2555 The rate we are measuring is messages per period, suitable for directly
2556 comparing with the limit. The average rate between now and the previous
2557 message is period / interval, which we feed into the EWMA as the sample.
2559 It turns out that the number of messages required for the smoothed rate
2560 to reach the limit when they are sent in a burst is equal to the limit.
2561 This can be seen by analysing the value of the smoothed rate after N
2562 messages sent at even intervals. Let k = (1 - a) * p/i
2564 rate_1 = (1 - a) * p/i + a * rate_0
2566 rate_2 = k + a * rate_1
2567 = k + a * k + a^2 * rate_0
2568 rate_3 = k + a * k + a^2 * k + a^3 * rate_0
2569 rate_N = rate_0 * a^N + k * SUM(x=0..N-1)(a^x)
2570 = rate_0 * a^N + k * (1 - a^N) / (1 - a)
2571 = rate_0 * a^N + p/i * (1 - a^N)
2573 When N is large, a^N -> 0 so rate_N -> p/i as desired.
2575 rate_N = p/i + (rate_0 - p/i) * a^N
2576 a^N = (rate_N - p/i) / (rate_0 - p/i)
2577 N * -i/p = log((rate_N - p/i) / (rate_0 - p/i))
2578 N = p/i * log((rate_0 - p/i) / (rate_N - p/i))
2580 Numerical analysis of the above equation, setting the computed rate to
2581 increase from rate_0 = 0 to rate_N = limit, shows that for large sending
2582 rates, p/i, the number of messages N = limit. So limit serves as both the
2583 maximum rate measured in messages per period, and the maximum number of
2584 messages that can be sent in a fast burst. */
2586 double this_time = (double)tv.tv_sec
2587 + (double)tv.tv_usec / 1000000.0;
2588 double prev_time = (double)dbd->time_stamp
2589 + (double)dbd->time_usec / 1000000.0;
2591 /* We must avoid division by zero, and deal gracefully with the clock going
2592 backwards. If we blunder ahead when time is in reverse then the computed
2593 rate will be bogus. To be safe we clamp interval to a very small number. */
2595 double interval = this_time - prev_time <= 0.0 ? 1e-9
2596 : this_time - prev_time;
2598 double i_over_p = interval / period;
2599 double a = exp(-i_over_p);
2601 /* Combine the instantaneous rate (period / interval) with the previous rate
2602 using the smoothing factor a. In order to measure sized events, multiply the
2603 instantaneous rate by the count of bytes or recipients etc. */
2605 dbd->time_stamp = tv.tv_sec;
2606 dbd->time_usec = tv.tv_usec;
2607 dbd->rate = (1 - a) * count / i_over_p + a * dbd->rate;
2609 /* When events are very widely spaced the computed rate tends towards zero.
2610 Although this is accurate it turns out not to be useful for our purposes,
2611 especially when the first event after a long silence is the start of a spam
2612 run. A more useful model is that the rate for an isolated event should be the
2613 size of the event per the period size, ignoring the lack of events outside
2614 the current period and regardless of where the event falls in the period. So,
2615 if the interval was so long that the calculated rate is unhelpfully small, we
2616 re-intialize the rate. In the absence of higher-rate bursts, the condition
2617 below is true if the interval is greater than the period. */
2619 if (dbd->rate < count) dbd->rate = count;
2622 /* Clients sending at the limit are considered to be over the limit.
2623 This matters for edge cases such as a limit of zero, when the client
2624 should be completely blocked. */
2626 rc = (dbd->rate < limit)? FAIL : OK;
2628 /* Update the state if the rate is low or if we are being strict. If we
2629 are in leaky mode and the sender's rate is too high, we do not update
2630 the recorded rate in order to avoid an over-aggressive sender's retry
2631 rate preventing them from getting any email through. If readonly is set,
2632 neither leaky nor strict are set, so we do not do any updates. */
2634 if ((rc == FAIL && leaky) || strict)
2636 dbfn_write(dbm, key, dbdb, dbdb_size);
2637 HDEBUG(D_acl) debug_printf("ratelimit db updated\n");
2641 HDEBUG(D_acl) debug_printf("ratelimit db not updated: %s\n",
2642 readonly? "readonly mode" : "over the limit, but leaky");
2647 /* Store the result in the tree for future reference. */
2649 t = store_get(sizeof(tree_node) + Ustrlen(key));
2651 Ustrcpy(t->name, key);
2652 (void)tree_insertnode(anchor, t);
2654 /* We create the formatted version of the sender's rate very late in
2655 order to ensure that it is done using the correct storage pool. */
2657 store_pool = old_pool;
2658 sender_rate = string_sprintf("%.1f", dbd->rate);
2661 debug_printf("ratelimit computed rate %s\n", sender_rate);
2668 /*************************************************
2669 * Handle conditions/modifiers on an ACL item *
2670 *************************************************/
2672 /* Called from acl_check() below.
2676 cb ACL condition block - if NULL, result is OK
2677 where where called from
2678 addr the address being checked for RCPT, or NULL
2679 level the nesting level
2680 epp pointer to pass back TRUE if "endpass" encountered
2681 (applies only to "accept" and "discard")
2682 user_msgptr user message pointer
2683 log_msgptr log message pointer
2684 basic_errno pointer to where to put verify error
2686 Returns: OK - all conditions are met
2687 DISCARD - an "acl" condition returned DISCARD - only allowed
2688 for "accept" or "discard" verbs
2689 FAIL - at least one condition fails
2690 FAIL_DROP - an "acl" condition returned FAIL_DROP
2691 DEFER - can't tell at the moment (typically, lookup defer,
2692 but can be temporary callout problem)
2693 ERROR - ERROR from nested ACL or expansion failure or other
2698 acl_check_condition(int verb, acl_condition_block *cb, int where,
2699 address_item *addr, int level, BOOL *epp, uschar **user_msgptr,
2700 uschar **log_msgptr, int *basic_errno)
2702 uschar *user_message = NULL;
2703 uschar *log_message = NULL;
2704 uschar *debug_tag = NULL;
2705 uschar *debug_opts = NULL;
2708 #ifdef WITH_CONTENT_SCAN
2712 for (; cb != NULL; cb = cb->next)
2717 /* The message and log_message items set up messages to be used in
2718 case of rejection. They are expanded later. */
2720 if (cb->type == ACLC_MESSAGE)
2722 user_message = cb->arg;
2726 if (cb->type == ACLC_LOG_MESSAGE)
2728 log_message = cb->arg;
2732 /* The endpass "condition" just sets a flag to show it occurred. This is
2733 checked at compile time to be on an "accept" or "discard" item. */
2735 if (cb->type == ACLC_ENDPASS)
2741 /* For other conditions and modifiers, the argument is expanded now for some
2742 of them, but not for all, because expansion happens down in some lower level
2743 checking functions in some cases. */
2745 if (cond_expand_at_top[cb->type])
2747 arg = expand_string(cb->arg);
2750 if (expand_string_forcedfail) continue;
2751 *log_msgptr = string_sprintf("failed to expand ACL string \"%s\": %s",
2752 cb->arg, expand_string_message);
2753 return search_find_defer? DEFER : ERROR;
2758 /* Show condition, and expanded condition if it's different */
2763 debug_printf("check %s%s %n",
2764 (!cond_modifiers[cb->type] && cb->u.negated)? "!":"",
2765 conditions[cb->type], &lhswidth);
2767 if (cb->type == ACLC_SET)
2769 debug_printf("acl_%s ", cb->u.varname);
2770 lhswidth += 5 + Ustrlen(cb->u.varname);
2773 debug_printf("= %s\n", cb->arg);
2776 debug_printf("%.*s= %s\n", lhswidth,
2780 /* Check that this condition makes sense at this time */
2782 if ((cond_forbids[cb->type] & (1 << where)) != 0)
2784 *log_msgptr = string_sprintf("cannot %s %s condition in %s ACL",
2785 cond_modifiers[cb->type]? "use" : "test",
2786 conditions[cb->type], acl_wherenames[where]);
2790 /* Run the appropriate test for each condition, or take the appropriate
2791 action for the remaining modifiers. */
2795 case ACLC_ADD_HEADER:
2799 /* A nested ACL that returns "discard" makes sense only for an "accept" or
2803 rc = acl_check_internal(where, addr, arg, level+1, user_msgptr, log_msgptr);
2804 if (rc == DISCARD && verb != ACL_ACCEPT && verb != ACL_DISCARD)
2806 *log_msgptr = string_sprintf("nested ACL returned \"discard\" for "
2807 "\"%s\" command (only allowed with \"accept\" or \"discard\")",
2813 case ACLC_AUTHENTICATED:
2814 rc = (sender_host_authenticated == NULL)? FAIL :
2815 match_isinlist(sender_host_authenticated, &arg, 0, NULL, NULL, MCL_STRING,
2819 #ifdef EXPERIMENTAL_BRIGHTMAIL
2820 case ACLC_BMI_OPTIN:
2822 int old_pool = store_pool;
2823 store_pool = POOL_PERM;
2824 bmi_current_optin = string_copy(arg);
2825 store_pool = old_pool;
2830 case ACLC_CONDITION:
2831 /* The true/false parsing here should be kept in sync with that used in
2832 expand.c when dealing with ECOND_BOOL so that we don't have too many
2833 different definitions of what can be a boolean. */
2834 if (Ustrspn(arg, "0123456789") == Ustrlen(arg)) /* Digits, or empty */
2835 rc = (Uatoi(arg) == 0)? FAIL : OK;
2837 rc = (strcmpic(arg, US"no") == 0 ||
2838 strcmpic(arg, US"false") == 0)? FAIL :
2839 (strcmpic(arg, US"yes") == 0 ||
2840 strcmpic(arg, US"true") == 0)? OK : DEFER;
2842 *log_msgptr = string_sprintf("invalid \"condition\" value \"%s\"", arg);
2845 case ACLC_CONTINUE: /* Always succeeds */
2849 control_type = decode_control(arg, &p, where, log_msgptr);
2851 /* Check if this control makes sense at this time */
2853 if ((control_forbids[control_type] & (1 << where)) != 0)
2855 *log_msgptr = string_sprintf("cannot use \"control=%s\" in %s ACL",
2856 controls[control_type], acl_wherenames[where]);
2860 switch(control_type)
2862 case CONTROL_AUTH_UNADVERTISED:
2863 allow_auth_unadvertised = TRUE;
2866 #ifdef EXPERIMENTAL_BRIGHTMAIL
2867 case CONTROL_BMI_RUN:
2872 #ifndef DISABLE_DKIM
2873 case CONTROL_DKIM_VERIFY:
2874 dkim_disable_verify = TRUE;
2881 case CONTROL_CASEFUL_LOCAL_PART:
2882 deliver_localpart = addr->cc_local_part;
2885 case CONTROL_CASELOWER_LOCAL_PART:
2886 deliver_localpart = addr->lc_local_part;
2889 case CONTROL_ENFORCE_SYNC:
2890 smtp_enforce_sync = TRUE;
2893 case CONTROL_NO_ENFORCE_SYNC:
2894 smtp_enforce_sync = FALSE;
2897 #ifdef WITH_CONTENT_SCAN
2898 case CONTROL_NO_MBOX_UNSPOOL:
2899 no_mbox_unspool = TRUE;
2903 case CONTROL_NO_MULTILINE:
2904 no_multiline_responses = TRUE;
2907 case CONTROL_NO_PIPELINING:
2908 pipelining_enable = FALSE;
2911 case CONTROL_NO_DELAY_FLUSH:
2912 disable_delay_flush = TRUE;
2915 case CONTROL_NO_CALLOUT_FLUSH:
2916 disable_callout_flush = TRUE;
2919 case CONTROL_FAKEDEFER:
2920 case CONTROL_FAKEREJECT:
2921 fake_response = (control_type == CONTROL_FAKEDEFER) ? DEFER : FAIL;
2925 while (*pp != 0) pp++;
2926 fake_response_text = expand_string(string_copyn(p+1, pp-p-1));
2931 /* Explicitly reset to default string */
2932 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).";
2936 case CONTROL_FREEZE:
2937 deliver_freeze = TRUE;
2938 deliver_frozen_at = time(NULL);
2939 freeze_tell = freeze_tell_config; /* Reset to configured value */
2940 if (Ustrncmp(p, "/no_tell", 8) == 0)
2947 *log_msgptr = string_sprintf("syntax error in \"control=%s\"", arg);
2952 case CONTROL_QUEUE_ONLY:
2953 queue_only_policy = TRUE;
2956 case CONTROL_SUBMISSION:
2957 originator_name = US"";
2958 submission_mode = TRUE;
2961 if (Ustrncmp(p, "/sender_retain", 14) == 0)
2964 active_local_sender_retain = TRUE;
2965 active_local_from_check = FALSE;
2967 else if (Ustrncmp(p, "/domain=", 8) == 0)
2970 while (*pp != 0 && *pp != '/') pp++;
2971 submission_domain = string_copyn(p+8, pp-p-8);
2974 /* The name= option must be last, because it swallows the rest of
2976 else if (Ustrncmp(p, "/name=", 6) == 0)
2979 while (*pp != 0) pp++;
2980 submission_name = string_copy(parse_fix_phrase(p+6, pp-p-6,
2981 big_buffer, big_buffer_size));
2988 *log_msgptr = string_sprintf("syntax error in \"control=%s\"", arg);
2996 if (Ustrncmp(p, "/tag=", 5) == 0)
2999 while (*pp != '\0' && *pp != '/') pp++;
3000 debug_tag = string_copyn(p+5, pp-p-5);
3003 else if (Ustrncmp(p, "/opts=", 6) == 0)
3006 while (*pp != '\0' && *pp != '/') pp++;
3007 debug_opts = string_copyn(p+6, pp-p-6);
3011 debug_logging_activate(debug_tag, debug_opts);
3014 case CONTROL_SUPPRESS_LOCAL_FIXUPS:
3015 suppress_local_fixups = TRUE;
3020 #ifdef EXPERIMENTAL_DCC
3023 /* Seperate the regular expression and any optional parameters. */
3024 uschar *ss = string_nextinlist(&arg, &sep, big_buffer, big_buffer_size);
3025 /* Run the dcc backend. */
3026 rc = dcc_process(&ss);
3027 /* Modify return code based upon the existance of options. */
3028 while ((ss = string_nextinlist(&arg, &sep, big_buffer, big_buffer_size))
3030 if (strcmpic(ss, US"defer_ok") == 0 && rc == DEFER)
3032 /* FAIL so that the message is passed to the next ACL */
3040 #ifdef WITH_CONTENT_SCAN
3042 rc = mime_decode(&arg);
3048 int delay = readconf_readtime(arg, 0, FALSE);
3051 *log_msgptr = string_sprintf("syntax error in argument for \"delay\" "
3052 "modifier: \"%s\" is not a time value", arg);
3057 HDEBUG(D_acl) debug_printf("delay modifier requests %d-second delay\n",
3062 debug_printf("delay skipped in -bh checking mode\n");
3065 /* It appears to be impossible to detect that a TCP/IP connection has
3066 gone away without reading from it. This means that we cannot shorten
3067 the delay below if the client goes away, because we cannot discover
3068 that the client has closed its end of the connection. (The connection
3069 is actually in a half-closed state, waiting for the server to close its
3070 end.) It would be nice to be able to detect this state, so that the
3071 Exim process is not held up unnecessarily. However, it seems that we
3072 can't. The poll() function does not do the right thing, and in any case
3073 it is not always available.
3075 NOTE 1: If ever this state of affairs changes, remember that we may be
3076 dealing with stdin/stdout here, in addition to TCP/IP connections.
3077 Also, delays may be specified for non-SMTP input, where smtp_out and
3078 smtp_in will be NULL. Whatever is done must work in all cases.
3080 NOTE 2: The added feature of flushing the output before a delay must
3081 apply only to SMTP input. Hence the test for smtp_out being non-NULL.
3086 if (smtp_out != NULL && !disable_delay_flush) mac_smtp_fflush();
3087 while (delay > 0) delay = sleep(delay);
3093 #ifdef WITH_OLD_DEMIME
3099 #ifndef DISABLE_DKIM
3100 case ACLC_DKIM_SIGNER:
3101 if (dkim_cur_signer != NULL)
3102 rc = match_isinlist(dkim_cur_signer,
3103 &arg,0,NULL,NULL,MCL_STRING,TRUE,NULL);
3108 case ACLC_DKIM_STATUS:
3109 rc = match_isinlist(dkim_exim_expand_query(DKIM_VERIFY_STATUS),
3110 &arg,0,NULL,NULL,MCL_STRING,TRUE,NULL);
3115 rc = verify_check_dnsbl(&arg);
3119 rc = match_isinlist(addr->domain, &arg, 0, &domainlist_anchor,
3120 addr->domain_cache, MCL_DOMAIN, TRUE, &deliver_domain_data);
3123 /* The value in tls_cipher is the full cipher name, for example,
3124 TLSv1:DES-CBC3-SHA:168, whereas the values to test for are just the
3125 cipher names such as DES-CBC3-SHA. But program defensively. We don't know
3126 what may in practice come out of the SSL library - which at the time of
3127 writing is poorly documented. */
3129 case ACLC_ENCRYPTED:
3130 if (tls_cipher == NULL) rc = FAIL; else
3132 uschar *endcipher = NULL;
3133 uschar *cipher = Ustrchr(tls_cipher, ':');
3134 if (cipher == NULL) cipher = tls_cipher; else
3136 endcipher = Ustrchr(++cipher, ':');
3137 if (endcipher != NULL) *endcipher = 0;
3139 rc = match_isinlist(cipher, &arg, 0, NULL, NULL, MCL_STRING, TRUE, NULL);
3140 if (endcipher != NULL) *endcipher = ':';
3144 /* Use verify_check_this_host() instead of verify_check_host() so that
3145 we can pass over &host_data to catch any looked up data. Once it has been
3146 set, it retains its value so that it's still there if another ACL verb
3147 comes through here and uses the cache. However, we must put it into
3148 permanent store in case it is also expected to be used in a subsequent
3149 message in the same SMTP connection. */
3152 rc = verify_check_this_host(&arg, sender_host_cache, NULL,
3153 (sender_host_address == NULL)? US"" : sender_host_address, &host_data);
3154 if (host_data != NULL) host_data = string_copy_malloc(host_data);
3157 case ACLC_LOCAL_PARTS:
3158 rc = match_isinlist(addr->cc_local_part, &arg, 0,
3159 &localpartlist_anchor, addr->localpart_cache, MCL_LOCALPART, TRUE,
3160 &deliver_localpart_data);
3163 case ACLC_LOG_REJECT_TARGET:
3169 while ((ss = string_nextinlist(&s, &sep, big_buffer, big_buffer_size))
3172 if (Ustrcmp(ss, "main") == 0) logbits |= LOG_MAIN;
3173 else if (Ustrcmp(ss, "panic") == 0) logbits |= LOG_PANIC;
3174 else if (Ustrcmp(ss, "reject") == 0) logbits |= LOG_REJECT;
3177 logbits |= LOG_MAIN|LOG_REJECT;
3178 log_write(0, LOG_MAIN|LOG_PANIC, "unknown log name \"%s\" in "
3179 "\"log_reject_target\" in %s ACL", ss, acl_wherenames[where]);
3182 log_reject_target = logbits;
3195 if (Ustrncmp(s, "main", 4) == 0)
3196 { logbits |= LOG_MAIN; s += 4; }
3197 else if (Ustrncmp(s, "panic", 5) == 0)
3198 { logbits |= LOG_PANIC; s += 5; }
3199 else if (Ustrncmp(s, "reject", 6) == 0)
3200 { logbits |= LOG_REJECT; s += 6; }
3203 logbits = LOG_MAIN|LOG_PANIC;
3204 s = string_sprintf(":unknown log name in \"%s\" in "
3205 "\"logwrite\" in %s ACL", arg, acl_wherenames[where]);
3211 while (isspace(*s)) s++;
3214 if (logbits == 0) logbits = LOG_MAIN;
3215 log_write(0, logbits, "%s", string_printing(s));
3219 #ifdef WITH_CONTENT_SCAN
3222 /* Separate the regular expression and any optional parameters. */
3223 uschar *ss = string_nextinlist(&arg, &sep, big_buffer, big_buffer_size);
3224 /* Run the malware backend. */
3226 /* Modify return code based upon the existance of options. */
3227 while ((ss = string_nextinlist(&arg, &sep, big_buffer, big_buffer_size))
3229 if (strcmpic(ss, US"defer_ok") == 0 && rc == DEFER)
3231 /* FAIL so that the message is passed to the next ACL */
3238 case ACLC_MIME_REGEX:
3239 rc = mime_regex(&arg);
3243 case ACLC_RATELIMIT:
3244 rc = acl_ratelimit(arg, where, log_msgptr);
3247 case ACLC_RECIPIENTS:
3248 rc = match_address_list(addr->address, TRUE, TRUE, &arg, NULL, -1, 0,
3252 #ifdef WITH_CONTENT_SCAN
3258 case ACLC_SENDER_DOMAINS:
3261 sdomain = Ustrrchr(sender_address, '@');
3262 sdomain = (sdomain == NULL)? US"" : sdomain + 1;
3263 rc = match_isinlist(sdomain, &arg, 0, &domainlist_anchor,
3264 sender_domain_cache, MCL_DOMAIN, TRUE, NULL);
3269 rc = match_address_list(sender_address, TRUE, TRUE, &arg,
3270 sender_address_cache, -1, 0, &sender_data);
3273 /* Connection variables must persist forever */
3277 int old_pool = store_pool;
3278 if (cb->u.varname[0] == 'c') store_pool = POOL_PERM;
3279 acl_var_create(cb->u.varname)->data.ptr = string_copy(arg);
3280 store_pool = old_pool;
3284 #ifdef WITH_CONTENT_SCAN
3287 /* Seperate the regular expression and any optional parameters. */
3288 uschar *ss = string_nextinlist(&arg, &sep, big_buffer, big_buffer_size);
3289 /* Run the spam backend. */
3291 /* Modify return code based upon the existance of options. */
3292 while ((ss = string_nextinlist(&arg, &sep, big_buffer, big_buffer_size))
3294 if (strcmpic(ss, US"defer_ok") == 0 && rc == DEFER)
3296 /* FAIL so that the message is passed to the next ACL */
3304 #ifdef EXPERIMENTAL_SPF
3306 rc = spf_process(&arg, sender_address, SPF_PROCESS_NORMAL);
3308 case ACLC_SPF_GUESS:
3309 rc = spf_process(&arg, sender_address, SPF_PROCESS_GUESS);
3313 /* If the verb is WARN, discard any user message from verification, because
3314 such messages are SMTP responses, not header additions. The latter come
3315 only from explicit "message" modifiers. However, put the user message into
3316 $acl_verify_message so it can be used in subsequent conditions or modifiers
3317 (until something changes it). */
3320 rc = acl_verify(where, addr, arg, user_msgptr, log_msgptr, basic_errno);
3321 acl_verify_message = *user_msgptr;
3322 if (verb == ACL_WARN) *user_msgptr = NULL;
3326 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "internal ACL error: unknown "
3327 "condition %d", cb->type);
3331 /* If a condition was negated, invert OK/FAIL. */
3333 if (!cond_modifiers[cb->type] && cb->u.negated)
3335 if (rc == OK) rc = FAIL;
3336 else if (rc == FAIL || rc == FAIL_DROP) rc = OK;
3339 if (rc != OK) break; /* Conditions loop */
3343 /* If the result is the one for which "message" and/or "log_message" are used,
3344 handle the values of these modifiers. If there isn't a log message set, we make
3345 it the same as the user message.
3347 "message" is a user message that will be included in an SMTP response. Unless
3348 it is empty, it overrides any previously set user message.
3350 "log_message" is a non-user message, and it adds to any existing non-user
3351 message that is already set.
3353 Most verbs have but a single return for which the messages are relevant, but
3354 for "discard", it's useful to have the log message both when it succeeds and
3355 when it fails. For "accept", the message is used in the OK case if there is no
3356 "endpass", but (for backwards compatibility) in the FAIL case if "endpass" is
3359 if (*epp && rc == OK) user_message = NULL;
3361 if (((1<<rc) & msgcond[verb]) != 0)
3364 uschar *old_user_msgptr = *user_msgptr;
3365 uschar *old_log_msgptr = (*log_msgptr != NULL)? *log_msgptr : old_user_msgptr;
3367 /* If the verb is "warn", messages generated by conditions (verification or
3368 nested ACLs) are always discarded. This also happens for acceptance verbs
3369 when they actually do accept. Only messages specified at this level are used.
3370 However, the value of an existing message is available in $acl_verify_message
3371 during expansions. */
3373 if (verb == ACL_WARN ||
3374 (rc == OK && (verb == ACL_ACCEPT || verb == ACL_DISCARD)))
3375 *log_msgptr = *user_msgptr = NULL;
3377 if (user_message != NULL)
3379 acl_verify_message = old_user_msgptr;
3380 expmessage = expand_string(user_message);
3381 if (expmessage == NULL)
3383 if (!expand_string_forcedfail)
3384 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand ACL message \"%s\": %s",
3385 user_message, expand_string_message);
3387 else if (expmessage[0] != 0) *user_msgptr = expmessage;
3390 if (log_message != NULL)
3392 acl_verify_message = old_log_msgptr;
3393 expmessage = expand_string(log_message);
3394 if (expmessage == NULL)
3396 if (!expand_string_forcedfail)
3397 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand ACL message \"%s\": %s",
3398 log_message, expand_string_message);
3400 else if (expmessage[0] != 0)
3402 *log_msgptr = (*log_msgptr == NULL)? expmessage :
3403 string_sprintf("%s: %s", expmessage, *log_msgptr);
3407 /* If no log message, default it to the user message */
3409 if (*log_msgptr == NULL) *log_msgptr = *user_msgptr;
3412 acl_verify_message = NULL;
3420 /*************************************************
3421 * Get line from a literal ACL *
3422 *************************************************/
3424 /* This function is passed to acl_read() in order to extract individual lines
3425 of a literal ACL, which we access via static pointers. We can destroy the
3426 contents because this is called only once (the compiled ACL is remembered).
3428 This code is intended to treat the data in the same way as lines in the main
3429 Exim configuration file. That is:
3431 . Leading spaces are ignored.
3433 . A \ at the end of a line is a continuation - trailing spaces after the \
3434 are permitted (this is because I don't believe in making invisible things
3435 significant). Leading spaces on the continued part of a line are ignored.
3437 . Physical lines starting (significantly) with # are totally ignored, and
3438 may appear within a sequence of backslash-continued lines.
3440 . Blank lines are ignored, but will end a sequence of continuations.
3443 Returns: a pointer to the next line
3447 static uschar *acl_text; /* Current pointer in the text */
3448 static uschar *acl_text_end; /* Points one past the terminating '0' */
3456 /* This loop handles leading blank lines and comments. */
3460 while (isspace(*acl_text)) acl_text++; /* Leading spaces/empty lines */
3461 if (*acl_text == 0) return NULL; /* No more data */
3462 yield = acl_text; /* Potential data line */
3464 while (*acl_text != 0 && *acl_text != '\n') acl_text++;
3466 /* If we hit the end before a newline, we have the whole logical line. If
3467 it's a comment, there's no more data to be given. Otherwise, yield it. */
3469 if (*acl_text == 0) return (*yield == '#')? NULL : yield;
3471 /* After reaching a newline, end this loop if the physical line does not
3472 start with '#'. If it does, it's a comment, and the loop continues. */
3474 if (*yield != '#') break;
3477 /* This loop handles continuations. We know we have some real data, ending in
3478 newline. See if there is a continuation marker at the end (ignoring trailing
3479 white space). We know that *yield is not white space, so no need to test for
3480 cont > yield in the backwards scanning loop. */
3485 for (cont = acl_text - 1; isspace(*cont); cont--);
3487 /* If no continuation follows, we are done. Mark the end of the line and
3496 /* We have encountered a continuation. Skip over whitespace at the start of
3497 the next line, and indeed the whole of the next line or lines if they are
3502 while (*(++acl_text) == ' ' || *acl_text == '\t');
3503 if (*acl_text != '#') break;
3504 while (*(++acl_text) != 0 && *acl_text != '\n');
3507 /* We have the start of a continuation line. Move all the rest of the data
3508 to join onto the previous line, and then find its end. If the end is not a
3509 newline, we are done. Otherwise loop to look for another continuation. */
3511 memmove(cont, acl_text, acl_text_end - acl_text);
3512 acl_text_end -= acl_text - cont;
3514 while (*acl_text != 0 && *acl_text != '\n') acl_text++;
3515 if (*acl_text == 0) return yield;
3518 /* Control does not reach here */
3525 /*************************************************
3526 * Check access using an ACL *
3527 *************************************************/
3529 /* This function is called from address_check. It may recurse via
3530 acl_check_condition() - hence the use of a level to stop looping. The ACL is
3531 passed as a string which is expanded. A forced failure implies no access check
3532 is required. If the result is a single word, it is taken as the name of an ACL
3533 which is sought in the global ACL tree. Otherwise, it is taken as literal ACL
3534 text, complete with newlines, and parsed as such. In both cases, the ACL check
3535 is then run. This function uses an auxiliary function for acl_read() to call
3536 for reading individual lines of a literal ACL. This is acl_getline(), which
3537 appears immediately above.
3540 where where called from
3541 addr address item when called from RCPT; otherwise NULL
3542 s the input string; NULL is the same as an empty ACL => DENY
3543 level the nesting level
3544 user_msgptr where to put a user error (for SMTP response)
3545 log_msgptr where to put a logging message (not for SMTP response)
3547 Returns: OK access is granted
3548 DISCARD access is apparently granted...
3549 FAIL access is denied
3550 FAIL_DROP access is denied; drop the connection
3551 DEFER can't tell at the moment
3556 acl_check_internal(int where, address_item *addr, uschar *s, int level,
3557 uschar **user_msgptr, uschar **log_msgptr)
3560 acl_block *acl = NULL;
3561 uschar *acl_name = US"inline ACL";
3564 /* Catch configuration loops */
3568 *log_msgptr = US"ACL nested too deep: possible loop";
3574 HDEBUG(D_acl) debug_printf("ACL is NULL: implicit DENY\n");
3578 /* At top level, we expand the incoming string. At lower levels, it has already
3579 been expanded as part of condition processing. */
3583 ss = expand_string(s);
3586 if (expand_string_forcedfail) return OK;
3587 *log_msgptr = string_sprintf("failed to expand ACL string \"%s\": %s", s,
3588 expand_string_message);
3594 while (isspace(*ss))ss++;
3596 /* If we can't find a named ACL, the default is to parse it as an inline one.
3597 (Unless it begins with a slash; non-existent files give rise to an error.) */
3601 /* Handle the case of a string that does not contain any spaces. Look for a
3602 named ACL among those read from the configuration, or a previously read file.
3603 It is possible that the pointer to the ACL is NULL if the configuration
3604 contains a name with no data. If not found, and the text begins with '/',
3605 read an ACL from a file, and save it so it can be re-used. */
3607 if (Ustrchr(ss, ' ') == NULL)
3609 tree_node *t = tree_search(acl_anchor, ss);
3612 acl = (acl_block *)(t->data.ptr);
3615 HDEBUG(D_acl) debug_printf("ACL \"%s\" is empty: implicit DENY\n", ss);
3618 acl_name = string_sprintf("ACL \"%s\"", ss);
3619 HDEBUG(D_acl) debug_printf("using ACL \"%s\"\n", ss);
3622 else if (*ss == '/')
3624 struct stat statbuf;
3625 fd = Uopen(ss, O_RDONLY, 0);
3628 *log_msgptr = string_sprintf("failed to open ACL file \"%s\": %s", ss,
3633 if (fstat(fd, &statbuf) != 0)
3635 *log_msgptr = string_sprintf("failed to fstat ACL file \"%s\": %s", ss,
3640 acl_text = store_get(statbuf.st_size + 1);
3641 acl_text_end = acl_text + statbuf.st_size + 1;
3643 if (read(fd, acl_text, statbuf.st_size) != statbuf.st_size)
3645 *log_msgptr = string_sprintf("failed to read ACL file \"%s\": %s",
3646 ss, strerror(errno));
3649 acl_text[statbuf.st_size] = 0;
3652 acl_name = string_sprintf("ACL \"%s\"", ss);
3653 HDEBUG(D_acl) debug_printf("read ACL from file %s\n", ss);
3657 /* Parse an ACL that is still in text form. If it came from a file, remember it
3658 in the ACL tree, having read it into the POOL_PERM store pool so that it
3659 persists between multiple messages. */
3663 int old_pool = store_pool;
3664 if (fd >= 0) store_pool = POOL_PERM;
3665 acl = acl_read(acl_getline, log_msgptr);
3666 store_pool = old_pool;
3667 if (acl == NULL && *log_msgptr != NULL) return ERROR;
3670 tree_node *t = store_get_perm(sizeof(tree_node) + Ustrlen(ss));
3671 Ustrcpy(t->name, ss);
3673 (void)tree_insertnode(&acl_anchor, t);
3677 /* Now we have an ACL to use. It's possible it may be NULL. */
3682 int basic_errno = 0;
3683 BOOL endpass_seen = FALSE;
3685 *log_msgptr = *user_msgptr = NULL;
3686 acl_temp_details = FALSE;
3688 if ((where == ACL_WHERE_QUIT || where == ACL_WHERE_NOTQUIT) &&
3689 acl->verb != ACL_ACCEPT &&
3690 acl->verb != ACL_WARN)
3692 *log_msgptr = string_sprintf("\"%s\" is not allowed in a QUIT or not-QUIT ACL",
3697 HDEBUG(D_acl) debug_printf("processing \"%s\"\n", verbs[acl->verb]);
3699 /* Clear out any search error message from a previous check before testing
3702 search_error_message = NULL;
3703 cond = acl_check_condition(acl->verb, acl->condition, where, addr, level,
3704 &endpass_seen, user_msgptr, log_msgptr, &basic_errno);
3706 /* Handle special returns: DEFER causes a return except on a WARN verb;
3707 ERROR always causes a return. */
3712 HDEBUG(D_acl) debug_printf("%s: condition test deferred\n", verbs[acl->verb]);
3713 if (basic_errno != ERRNO_CALLOUTDEFER)
3715 if (search_error_message != NULL && *search_error_message != 0)
3716 *log_msgptr = search_error_message;
3717 if (smtp_return_error_details) acl_temp_details = TRUE;
3721 acl_temp_details = TRUE;
3723 if (acl->verb != ACL_WARN) return DEFER;
3726 default: /* Paranoia */
3728 HDEBUG(D_acl) debug_printf("%s: condition test error\n", verbs[acl->verb]);
3732 HDEBUG(D_acl) debug_printf("%s: condition test succeeded\n",
3737 HDEBUG(D_acl) debug_printf("%s: condition test failed\n", verbs[acl->verb]);
3740 /* DISCARD and DROP can happen only from a nested ACL condition, and
3741 DISCARD can happen only for an "accept" or "discard" verb. */
3744 HDEBUG(D_acl) debug_printf("%s: condition test yielded \"discard\"\n",
3749 HDEBUG(D_acl) debug_printf("%s: condition test yielded \"drop\"\n",
3754 /* At this point, cond for most verbs is either OK or FAIL or (as a result of
3755 a nested ACL condition) FAIL_DROP. However, for WARN, cond may be DEFER, and
3756 for ACCEPT and DISCARD, it may be DISCARD after a nested ACL call. */
3761 if (cond == OK || cond == DISCARD) return cond;
3764 HDEBUG(D_acl) debug_printf("accept: endpass encountered - denying access\n");
3772 acl_temp_details = TRUE;
3778 if (cond == OK) return FAIL;
3782 if (cond == OK || cond == DISCARD) return DISCARD;
3785 HDEBUG(D_acl) debug_printf("discard: endpass encountered - denying access\n");
3791 if (cond == OK) return FAIL_DROP;
3795 if (cond != OK) return cond;
3800 acl_warn(where, *user_msgptr, *log_msgptr);
3801 else if (cond == DEFER && (log_extra_selector & LX_acl_warn_skipped) != 0)
3802 log_write(0, LOG_MAIN, "%s Warning: ACL \"warn\" statement skipped: "
3803 "condition test deferred%s%s", host_and_ident(TRUE),
3804 (*log_msgptr == NULL)? US"" : US": ",
3805 (*log_msgptr == NULL)? US"" : *log_msgptr);
3806 *log_msgptr = *user_msgptr = NULL; /* In case implicit DENY follows */
3810 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "internal ACL error: unknown verb %d",
3815 /* Pass to the next ACL item */
3820 /* We have reached the end of the ACL. This is an implicit DENY. */
3822 HDEBUG(D_acl) debug_printf("end of %s: implicit DENY\n", acl_name);
3827 /*************************************************
3828 * Check access using an ACL *
3829 *************************************************/
3831 /* This is the external interface for ACL checks. It sets up an address and the
3832 expansions for $domain and $local_part when called after RCPT, then calls
3833 acl_check_internal() to do the actual work.
3836 where ACL_WHERE_xxxx indicating where called from
3837 recipient RCPT address for RCPT check, else NULL
3838 s the input string; NULL is the same as an empty ACL => DENY
3839 user_msgptr where to put a user error (for SMTP response)
3840 log_msgptr where to put a logging message (not for SMTP response)
3842 Returns: OK access is granted by an ACCEPT verb
3843 DISCARD access is granted by a DISCARD verb
3844 FAIL access is denied
3845 FAIL_DROP access is denied; drop the connection
3846 DEFER can't tell at the moment
3851 acl_check(int where, uschar *recipient, uschar *s, uschar **user_msgptr,
3852 uschar **log_msgptr)
3856 address_item *addr = NULL;
3858 *user_msgptr = *log_msgptr = NULL;
3859 sender_verified_failed = NULL;
3860 ratelimiters_cmd = NULL;
3861 log_reject_target = LOG_MAIN|LOG_REJECT;
3863 if (where == ACL_WHERE_RCPT)
3865 adb = address_defaults;
3867 addr->address = recipient;
3868 if (deliver_split_address(addr) == DEFER)
3870 *log_msgptr = US"defer in percent_hack_domains check";
3873 deliver_domain = addr->domain;
3874 deliver_localpart = addr->local_part;
3877 rc = acl_check_internal(where, addr, s, 0, user_msgptr, log_msgptr);
3879 deliver_domain = deliver_localpart = deliver_address_data =
3880 sender_address_data = NULL;
3882 /* A DISCARD response is permitted only for message ACLs, excluding the PREDATA
3883 ACL, which is really in the middle of an SMTP command. */
3887 if (where > ACL_WHERE_NOTSMTP || where == ACL_WHERE_PREDATA)
3889 log_write(0, LOG_MAIN|LOG_PANIC, "\"discard\" verb not allowed in %s "
3890 "ACL", acl_wherenames[where]);
3896 /* A DROP response is not permitted from MAILAUTH */
3898 if (rc == FAIL_DROP && where == ACL_WHERE_MAILAUTH)
3900 log_write(0, LOG_MAIN|LOG_PANIC, "\"drop\" verb not allowed in %s "
3901 "ACL", acl_wherenames[where]);
3905 /* Before giving a response, take a look at the length of any user message, and
3906 split it up into multiple lines if possible. */
3908 *user_msgptr = string_split_message(*user_msgptr);
3909 if (fake_response != OK)
3910 fake_response_text = string_split_message(fake_response_text);
3917 /*************************************************
3918 * Create ACL variable *
3919 *************************************************/
3921 /* Create an ACL variable or reuse an existing one. ACL variables are in a
3922 binary tree (see tree.c) with acl_var_c and acl_var_m as root nodes.
3925 name pointer to the variable's name, starting with c or m
3927 Returns the pointer to variable's tree node
3931 acl_var_create(uschar *name)
3933 tree_node *node, **root;
3934 root = (name[0] == 'c')? &acl_var_c : &acl_var_m;
3935 node = tree_search(*root, name);
3938 node = store_get(sizeof(tree_node) + Ustrlen(name));
3939 Ustrcpy(node->name, name);
3940 (void)tree_insertnode(root, node);
3942 node->data.ptr = NULL;
3948 /*************************************************
3949 * Write an ACL variable in spool format *
3950 *************************************************/
3952 /* This function is used as a callback for tree_walk when writing variables to
3953 the spool file. To retain spool file compatibility, what is written is -aclc or
3954 -aclm followed by the rest of the name and the data length, space separated,
3955 then the value itself, starting on a new line, and terminated by an additional
3956 newline. When we had only numbered ACL variables, the first line might look
3957 like this: "-aclc 5 20". Now it might be "-aclc foo 20" for the variable called
3961 name of the variable
3962 value of the variable
3963 ctx FILE pointer (as a void pointer)
3969 acl_var_write(uschar *name, uschar *value, void *ctx)
3971 FILE *f = (FILE *)ctx;
3972 fprintf(f, "-acl%c %s %d\n%s\n", name[0], name+1, Ustrlen(value), value);