chiark / gitweb /
1b671eff9258b429c525bf51e008d88c7339ee90
[exim-config] / base.m4
1 ### -*-m4-*-
2 ###
3 ### Basic settings for distorted.org.uk Exim configuration
4 ###
5 ### (c) 2012 Mark Wooding
6 ###
7
8 ###----- Licensing notice ---------------------------------------------------
9 ###
10 ### This program is free software; you can redistribute it and/or modify
11 ### it under the terms of the GNU General Public License as published by
12 ### the Free Software Foundation; either version 2 of the License, or
13 ### (at your option) any later version.
14 ###
15 ### This program is distributed in the hope that it will be useful,
16 ### but WITHOUT ANY WARRANTY; without even the implied warranty of
17 ### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18 ### GNU General Public License for more details.
19 ###
20 ### You should have received a copy of the GNU General Public License
21 ### along with this program; if not, write to the Free Software Foundation,
22 ### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
23
24 ###--------------------------------------------------------------------------
25 ### Global settings.
26
27 SECTION(global, priv)m4_dnl
28 admin_groups = CONF_admin_groups
29 trusted_groups = CONF_trusted_groups
30 prod_requires_admin = false
31
32 SECTION(global, logging)m4_dnl
33 log_file_path = : syslog
34 log_selector = \
35         +smtp_confirmation \
36         +tls_peerdn
37 log_timezone = true
38 syslog_duplication = false
39 syslog_timestamp = false
40
41 SECTION(global, daemon)m4_dnl
42 local_interfaces = <; CONF_interfaces
43 extra_local_interfaces = <; 0.0.0.0 ; ::0
44
45 SECTION(global, resource)m4_dnl
46 deliver_queue_load_max = 8
47 message_size_limit = 500M
48 queue_only_load = 12
49 smtp_accept_max = 16
50 smtp_accept_queue = 32
51 smtp_accept_reserve = 4
52 smtp_load_reserve = 10
53 smtp_reserve_hosts = +trusted
54
55 SECTION(global, policy)m4_dnl
56 host_lookup = *
57
58 SECTION(global, users)m4_dnl
59 gecos_name = $1
60 gecos_pattern = ([^,:]*)
61
62 SECTION(global, incoming)m4_dnl
63 rfc1413_hosts = *
64 rfc1413_query_timeout = 10s
65 received_header_text = Received: \
66         ${if def:sender_rcvhost \
67              {from $sender_rcvhost\n\t} \
68              {${if def:sender_ident \
69                    {from ${quote_local_part:$sender_ident} }}}}\
70         by $primary_hostname \
71         (Exim $version_number)\
72         ${if def:tls_cipher {\n\t} { }}\
73         ${if def:received_protocol \
74              {with $received_protocol \
75               ${if def:tls_cipher {(cipher=$tls_cipher)}}}}\n\t\
76         ${if def:sender_address \
77              {(envelope-from $sender_address\
78               ${if def:authenticated_id \
79                    {; auth=${quote_local_part:$authenticated_id}} \
80                    {${if and {{def:authenticated_sender} \
81                               {match_address{$authenticated_sender} \
82                                             {*@CONF_master_domain}}} \
83                          {; auth=${quote_local_part:\
84                                     ${local_part:\
85                                       $authenticated_sender}}}}}})\n\t}}\
86         id $message_exim_id\
87         ${if def:received_for {\n\tfor $received_for}}
88
89 SECTION(global, smtp)m4_dnl
90 smtp_return_error_details = true
91 accept_8bitmime = true
92 chunking_advertise_hosts =
93
94 SECTION(global, env)m4_dnl
95 keep_environment =
96
97 SECTION(global, process)m4_dnl
98 extract_addresses_remove_arguments = false
99 headers_charset = utf-8
100 qualify_domain = CONF_master_domain
101 untrusted_set_sender = *
102 local_from_check = false
103 local_sender_retain = true
104
105 SECTION(global, bounce)m4_dnl
106 delay_warning = 1h : 24h : 2d
107
108 SECTION(global, tls)m4_dnl
109 tls_certificate = CONF_certlist
110 tls_privatekey = CONF_sysconf_dir/server.key
111 tls_advertise_hosts = ${if exists {CONF_sysconf_dir/server.key} {*}{}}
112 tls_dhparam = CONF_ca_dir/dh-param-2048.pem
113 tls_require_ciphers = ${if or {{={$received_port}{CONF_submission_port}} \
114                                {match_ip {$sender_host_address}{+trusted}}} \
115                            {CONF_good_ciphers} \
116                            {CONF_acceptable_ciphers}}
117 tls_verify_certificates = CONF_ca_dir/ca.cert
118 tls_verify_hosts = ${if eq{$acl_c_mode}{submission} {} {+allnets}}
119
120 DIVERT(null)
121 ###--------------------------------------------------------------------------
122 ### Access control lists.
123
124 SECTION(global, acl-after)
125 SECTION(global, acl)m4_dnl
126 acl_smtp_helo = helo
127 SECTION(acl, misc)m4_dnl
128 helo:
129         ## Don't worry if this is local submission.  MUAs won't necessarily
130         ## have a clear idea of their hostnames.  (For some reason.)
131         accept   condition = ${if eq{$acl_c_mode}{submission}}
132
133         ## Check that the caller's claimed identity is actually plausible.
134         ## This seems like it's a fairly effective filter on spamminess, but
135         ## it's too blunt a tool.  Rather than reject, add a warning header.
136         ## Only we can't do this the easy way, so save it up for use in MAIL.
137         ## Also, we're liable to get a subsequent HELO (e.g., after STARTTLS)
138         ## and we should only care about the most recent one.
139         warn     set acl_c_helo_warning = false
140                 !condition = \
141                         ${if and {{match_ip {$sender_host_address} \
142                                             {<; 127.0.0.0/8 ; ::1}} \
143                                   {match_domain {$sender_helo_name} \
144                                                 {localhost : +thishost}}}}
145                 !condition = \
146                         ${if exists {CONF_sysconf_dir/helo.conf} \
147                              {${lookup {$sender_helo_name} \
148                                        partial0-lsearch \
149                                        {CONF_sysconf_dir/helo.conf} \
150                                        {${if match_ip \
151                                              {$sender_host_address} \
152                                              {<; $value}}}}}}
153                 !verify = helo
154                  set acl_c_helo_warning = true
155
156         accept
157
158 SECTION(global, acl)m4_dnl
159 acl_not_smtp_start = not_smtp_start
160 SECTION(acl, misc)m4_dnl
161 not_smtp_start:
162         ## Record the user's name.
163         warn     set acl_c_user = $sender_ident
164                  set acl_m_user = $sender_ident
165
166         ## Done.
167         accept
168
169 SECTION(global, acl)m4_dnl
170 acl_smtp_mail = mail
171 SECTION(acl, mail)m4_dnl
172 mail:
173
174         ## If we stashed a warning header about HELO from earlier, we should
175         ## add it now.  Only don't bother if the client has authenticated
176         ## successfully for submission (because we can't expect mobile
177         ## clients to be properly set up knowing their names), or it's one of
178         ## our own satellites (because they're either properly set up anyway,
179         ## or satellites using us as a smarthost).
180         warn     condition = $acl_c_helo_warning
181                 !condition = ${if eq{$acl_c_mode}{submission}}
182                 !hosts = +allnets
183                  WARNING_HEADER(BADHELO,
184                                 <:Client's HELO doesn't match its IP address.\n\t\
185                                   helo-name=$sender_helo_name \
186                                   address=$sender_host_address:>)
187
188         ## Always allow the empty sender, so that we can receive bounces.
189         accept   senders = :
190
191         ## Ensure that the sender looks valid.
192         require  acl = mail_check_sender
193
194         ## If this is directly from a client then hack on it for a while.
195         warn     condition = ${if eq{$acl_c_mode}{submission}}
196                  control = submission/sender_retain
197
198         ## Insist that a local client connect through TLS.
199         deny     message = Hosts within CONF_master_domain must use TLS
200                 !condition = ${if eq{$acl_c_mode}{submission}}
201                  hosts = +allnets
202                 !encrypted = *
203
204         ## Check that a submitted message's sender address is allowable.
205         require  acl = mail_check_auth
206
207 SECTION(acl, mail-tail)m4_dnl
208         ## And we're done.
209         accept
210
211 SECTION(acl, misc)m4_dnl
212 mail_check_sender:
213
214         ## See whether there's a special exception for this sender domain.
215         accept   senders = ${LOOKUP_DOMAIN($sender_address_domain,
216                              {KV(senders)})}
217
218         ## Ensure that the sender is routable.  This is important to prevent
219         ## undeliverable bounces.
220         require  message = Invalid sender; \
221                         ($sender_verify_failure; $acl_verify_message)
222                  verify = sender
223
224         ## We're good, then.
225         accept
226
227 SECTION(global, acl)m4_dnl
228 acl_smtp_connect = connect
229 SECTION(acl, connect)m4_dnl
230 connect:
231 SECTION(acl, connect-tail)m4_dnl
232         ## Configure variables according to the submission mode.
233         warn     acl = check_submission
234
235         ## Done.
236         accept
237
238 check_submission:
239         ## See whether this message needs hacking on.
240         accept  !hosts = +thishost
241                 !condition = ${if ={$received_port}{CONF_submission_port}}
242                  set acl_c_mode = relay
243
244         ## Remember to apply submission controls.
245         warn     set acl_c_mode = submission
246                  control = no_enforce_sync
247
248         ## Done.
249         accept
250
251 SECTION(global, acl)m4_dnl
252 acl_smtp_rcpt = rcpt
253 SECTION(acl, rcpt)m4_dnl
254 rcpt:
255
256         ## Reject if the client isn't allowed to relay and the recipient
257         ## isn't in one of our known domains.
258         require  message = Relaying not permitted
259                  acl = check_relay
260
261         ## Ensure that the recipient is routable.
262         require  message = Invalid recipient \
263                         ($recipient_verify_failure; $acl_verify_message)
264                  verify = recipient
265
266 SECTION(acl, misc)m4_dnl
267 check_relay:
268         ## Accept either if the client is allowed to relay through us, or if
269         ## we're the correct place to send this mail.
270
271         ## Known clients and authenticated users are OK.
272         accept   hosts = CONF_relay_clients
273         accept   authenticated = *
274
275         ## Known domains are OK.
276         accept   domains = +public
277
278         ## Finally, domains in our table are OK, unless they say they aren't.
279         accept   domains = \
280                  ${if exists{CONF_sysconf_dir/domains.conf} \
281                      {partial0-lsearch; CONF_sysconf_dir/domains.conf}}
282                  condition = DOMKV(service, {$value}{true})
283
284         ## Nope, that's not allowed.
285         deny
286
287 SECTION(acl, rcpt-tail)m4_dnl
288         ## Everything checks out OK: let this one go through.
289         accept
290
291 SECTION(global, acl)m4_dnl
292 acl_smtp_data = data
293 SECTION(acl, data)m4_dnl
294 data:
295         ## Don't accept messages with overly-long lines.
296         deny     message = line length exceeds SMTP permitted maximum: \
297                         $max_received_linelength > 998
298                  condition = ${if >{$max_received_linelength}{998}}
299
300 SECTION(acl, data-tail)m4_dnl
301         accept
302
303 SECTION(global, acl)m4_dnl
304 acl_smtp_expn = expn_vrfy
305 acl_smtp_vrfy = expn_vrfy
306 SECTION(acl, misc)m4_dnl
307 expn_vrfy:
308         accept   hosts = +trusted
309         deny     message = Suck it and see
310
311 DIVERT(null)
312 ###--------------------------------------------------------------------------
313 ### Verification of sender address.
314
315 SECTION(acl, misc)m4_dnl
316 mail_check_auth:
317
318         ## If this isn't a submission then it doesn't need checking.
319         accept   condition = ${if !eq{$acl_c_mode}{submission}}
320
321         ## If the caller hasn't formally authenticated, but this is a
322         ## loopback connection, then we can trust identd to tell us the right
323         ## answer.  So we should stash the right name somewhere consistent.
324         warn     set acl_c_user = $authenticated_id
325                  hosts = +thishost
326                 !authenticated = *
327                  condition = ${if def:sender_ident}
328                  set acl_c_user = $sender_ident
329
330         ## User must be authenticated by now.
331         deny     message = Sender not authenticated
332                  condition = ${if !def:acl_c_user}
333
334         ## Set the per-message authentication flag, since we now know that
335         ## there's a sensible value.
336         warn     set acl_m_user = $acl_c_user
337
338         ## All done.
339         accept
340
341 DIVERT(null)
342 ###--------------------------------------------------------------------------
343 ### Common options for forwarding routers.
344
345 ## We're pretty permissive here.
346 m4_define(<:FILTER_BASE:>,
347         <:driver = redirect
348         modemask = 002
349         check_owner = false
350         check_group = false
351         allow_filter = true
352         allow_defer = true
353         allow_fail = true
354         forbid_blackhole = false
355         check_ancestor = true:>)
356
357 ## Common options for forwarding routers at verification time.
358 m4_define(<:FILTER_VERIFY:>,
359         <:verify_only = true
360         user = CONF_filter_user
361         forbid_filter_dlfunc = true
362         forbid_filter_logwrite = true
363         forbid_filter_perl = true
364         forbid_filter_readsocket = true
365         forbid_filter_run = true
366         file_transport = dummy
367         directory_transport = dummy
368         pipe_transport = dummy
369         reply_transport = dummy:>)
370
371 ## Transports for redirection filters.
372 m4_define(<:FILTER_TRANSPORTS:>,
373         <:file_transport = mailbox
374         directory_transport = maildir
375         pipe_transport = pipe
376         reply_transport = reply:>)
377
378 m4_define(<:FILTER_ROUTER:>,
379 <:$1_vrf:
380         $2
381         FILTER_VERIFY<::>$3
382 $1:
383         $2
384         verify = no
385         FILTER_TRANSPORTS<::>$4:>)
386
387 DIVERT(null)
388 ###--------------------------------------------------------------------------
389 ### Common routers.
390
391 SECTION(routers, alias)m4_dnl
392 ## Look up the local part in the address map.
393 alias:
394         driver = redirect
395         allow_fail = true
396         allow_defer = true
397         user = CONF_filter_user
398         FILTER_TRANSPORTS
399         local_parts = nwildlsearch; CONF_alias_file
400         data = ${expand:$local_part_data}
401 SECTION(routers, alias-opts)m4_dnl
402
403 DIVERT(null)
404 ###--------------------------------------------------------------------------
405 ### Some standard transports.
406
407 m4_define(<:USER_DELIVERY:>,
408         <:delivery_date_add = true
409         envelope_to_add = true
410         return_path_add = true:>)
411
412 m4_define(<:APPLY_HEADER_CHANGES:>,
413         <:headers_add = m4_ifelse(<:$1:>, <::>,
414                 <:$acl_m_hdradd:>,
415                 <:${if def:acl_m_hdradd{$acl_m_hdradd\n}}\
416                 $1:>)
417         headers_remove = m4_ifelse(<:$2:>, <::>,
418                 <:$acl_m_hdrrm:>,
419                 <:${if def:acl_m_hdrrm{$acl_m_hdrrm:}}\
420                 $2:>):>)
421
422 m4_define(<:DKIM_SIGN_P:>,
423         <:and {{exists{CONF_sysconf_dir/dkim-sign.conf}} \
424                {!def:h_DKIM-Signature:} \
425                {!def:h_List-ID:} \
426                {or {{def:authenticated_id} \
427                     {def:authenticated_sender}}}}:>)
428
429 m4_define(<:DKIM_KEYS_INSTANCE:>,
430         <:${lookup {${domain:$h_From:}} partial0-lsearch \
431                         {CONF_sysconf_dir/dkim-sign.conf} \
432                 _LOOKUP_ARGS(<:$1:>, <:$2:>)}:>)
433 m4_define(<:DKIM_KEYS_STATE:>, <:${lookup {$1} lsearch \
434                 {DKIM_KEYS_INSTANCE(<:{CONF_dkim_keys_dir/$value/active/dkim-keys.state}:>)} \
435         _LOOKUP_ARGS(<:$2:>, <:$3:>, <:fail:>)}:>)
436 m4_define(<:DKIM_KEYS_INFO:>, <:DKIM_KEYS_STATE(<:params:>,
437         <:{${if and {{>={$tod_epoch}{KV(t0)}} \
438                     {<{$tod_epoch}{${eval:KV(t0) + KV(n)*KV(step)}}}} \
439                 {DKIM_KEYS_STATE(<:info.${eval:($tod_epoch - KV(t0))/KV(step)}:>,
440                         <:$1:>, <:$2:>)} \
441                 m4_ifelse(<:$2:>, <::>, <:fail:>, <:$2:>)}}:>,
442         m4_ifelse(<:$2:>, <::>, <:fail:>, <:$2:>)):>)
443
444 m4_define(<:DKIM_SIGN:>,
445         <:dkim_domain = \
446                 ${if DKIM_SIGN_P \
447                         {DKIM_KEYS_INSTANCE({${domain:$h_From:}})}}
448         dkim_selector = DKIM_KEYS_INFO(<:{KV(k)}:>)
449         dkim_private_key = \
450                 DKIM_KEYS_INSTANCE(<:m4_dnl
451                         {CONF_dkim_keys_dir/$value/active/$dkim_selector.priv}:>)
452         dkim_canon = relaxed
453         dkim_strict = true
454         ## The following ridiculous stunt does two important jobs.  Firstly,
455         ## and more obviously, it arranges to include one more copy of each
456         ## header name than the message actually contains, thereby causing
457         ## the signature to fail if another header with the same name is
458         ## added.  And secondly, and far more subtly, it also trims the
459         ## spaces from the header names so that they're in the format that
460         ## the signing machinery secretly wants.
461         dkim_sign_headers = \
462                 ${sg {${map {CONF_dkim_headers : \
463                              X-CONF_header_token-DKIM-Key-Publication} \
464                             {$item${sg {${expand:\$h_$item:}\n} \
465                                        {((?:[^\n]+|\n\\s+)*)\n} \
466                                        {:$item}}}}} \
467                      {::}{:}}
468         headers_add = \
469                 ${if DKIM_SIGN_P \
470                         {DKIM_KEYS_INFO(<:m4_dnl
471                                 {X-CONF_header_token-DKIM-Key-Publication: \
472                                         DKIM signature not suitable for \
473                                         as evidence after delivery; \
474                                         DKIM private key KV(k) will be \
475                                         published at KV(u) on or before \
476                                         KV(tpub)}:>)}}:>)
477
478 m4_define(<:SMTP_DELIVERY:>,
479         <:## Prevent sending messages with overly long lines.  The use of
480         ## `message_size_limit' here is somewhat misleading.
481         message_size_limit = ${if >{$max_received_linelength}{998}{1}{0}}:>)
482
483 SECTION(transports)m4_dnl
484 ## A standard transport for remote delivery.  By default, try to do TLS, and
485 ## don't worry too much if it's not very secure: the alternative is sending
486 ## in plaintext anyway.  But all of this can be overridden from the
487 ## `domains.conf' file.  Annoyingly, the `tls_dh_min_bits' setting isn't
488 ## expanded before use, so we can't set it the obvious way.  Instead, encode
489 ## it into the transport name.  This is very unpleasant, of course.
490 smtp:
491         driver = smtp
492         SMTP_DELIVERY
493         APPLY_HEADER_CHANGES
494         DKIM_SIGN
495         tls_require_ciphers = CONF_acceptable_ciphers
496         tls_dh_min_bits = 508
497         tls_tempfail_tryclear = true
498
499 m4_define(<:SMTP_TRANS_DHBITS:>,
500         <:driver = smtp
501         SMTP_DELIVERY
502         APPLY_HEADER_CHANGES
503         DKIM_SIGN
504         hosts_try_auth = *
505         hosts_require_tls = DOMKV(tls-peer-ca, {*}{})
506         hosts_require_auth = \
507                 ${if bool {DOMKV(require-auth, {$value}{false})} {*}{}}
508         tls_certificate = DOMKV(tls-certificate, {${expand:$value}}fail)
509         tls_privatekey = DOMKV(tls-private-key, {${expand:$value}}fail)
510         tls_verify_certificates = DOMKV(tls-peer-ca, {${expand:$value}}fail)
511         tls_require_ciphers = \
512                 DOMKV(tls-ciphers,
513                       {${extract {${expand:$value}} \
514                                  { good = CONF_good_ciphers \
515                                    any = CONF_acceptable_ciphers } \
516                                  {$value} \
517                                  {${expand:$value}}}} \
518                       {CONF_acceptable_ciphers})
519         tls_dh_min_bits = $1
520         tls_tempfail_tryclear = true:>)m4_dnl
521 smtp_dhbits_512:
522         SMTP_TRANS_DHBITS(508)
523 smtp_dhbits_768:
524         SMTP_TRANS_DHBITS(764)
525 smtp_dhbits_1024:
526         SMTP_TRANS_DHBITS(1020)
527 smtp_dhbits_2048:
528         SMTP_TRANS_DHBITS(2044)
529
530 ## Transport to a local SMTP server; use TLS and perform client
531 ## authentication.
532 smtp_local:
533         driver = smtp
534         SMTP_DELIVERY
535         APPLY_HEADER_CHANGES
536         hosts_require_tls = *
537         tls_certificate = CONF_sysconf_dir/client.certlist
538         tls_privatekey = CONF_sysconf_dir/client.key
539         tls_verify_certificates = CONF_ca_dir/ca.cert
540         tls_require_ciphers = CONF_good_ciphers
541         tls_dh_min_bits = 2046
542         tls_tempfail_tryclear = false
543         authenticated_sender_force = true
544         authenticated_sender = \
545                 ${if def:acl_m_user {$acl_m_user@CONF_master_domain} \
546                      {${if def:authenticated_sender {$authenticated_sender} \
547                            fail}}}
548
549 ## A standard transport for local delivery.
550 deliver:
551         driver = appendfile
552         APPLY_HEADER_CHANGES
553         file = /var/mail/$local_part
554         group = mail
555         mode = 0600
556         mode_fail_narrower = false
557         USER_DELIVERY
558
559 ## Transports for user filters.
560 mailbox:
561         driver = appendfile
562         APPLY_HEADER_CHANGES
563         initgroups = true
564         USER_DELIVERY
565
566 maildir:
567         driver = appendfile
568         APPLY_HEADER_CHANGES
569         maildir_format = true
570         initgroups = true
571         USER_DELIVERY
572
573 pipe:
574         driver = pipe
575         APPLY_HEADER_CHANGES
576         path = ${if and {{def:home} {exists{$home/bin}}} {$home/bin:} {}}\
577                 /usr/local/bin:/usr/local/sbin:\
578                 /usr/bin:/usr/sbin:/bin:/sbin
579         initgroups = true
580         umask = 002
581         return_fail_output = true
582         log_output = true
583
584 ## A special dummy transport for use during address verification.
585 dummy:
586         driver = appendfile
587         file = /dev/null
588
589 DIVERT(null)
590 ###--------------------------------------------------------------------------
591 ### Retry configuration.
592
593 SECTION(retry, default)m4_dnl
594 ## Be persistent when sending to the site relay.  It ought to work, but
595 ## particularly satellites such as laptops often encounter annoying temporary
596 ## failures due to network unavailability, and the usual gradual policy can
597 ## leave mail building up for no good reason.
598 CONF_smarthost                          * \
599         F,4d,15m
600
601 ## Default.
602 *                                       * \
603         F,2h,15m; G,16h,2h,1.5; F,4d,6h
604
605 DIVERT(null)
606 ###----- That's all, folks --------------------------------------------------