chiark - git - mdw - exim-config/blob - 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 queue_only_load = 12
  48 smtp_accept_max = 16
  49 smtp_accept_queue = 32
  50 smtp_accept_reserve = 4
  51 smtp_load_reserve = 10
  52 smtp_reserve_hosts = +trusted
  53
  54 SECTION(global, policy)m4_dnl
  55 host_lookup = *
  56
  57 SECTION(global, users)m4_dnl
  58 gecos_name = $1
  59 gecos_pattern = ([^,:]*)
  60
  61 SECTION(global, incoming)m4_dnl
  62 received_header_text = Received: \
  63         ${if def:sender_rcvhost \
  64              {from $sender_rcvhost\n\t} \
  65              {${if def:sender_ident \
  66                    {from ${quote_local_part:$sender_ident} }}}}\
  67         by $primary_hostname \
  68         (Exim $version_number)\
  69         ${if def:tls_cipher {\n\t} { }}\
  70         ${if def:received_protocol \
  71              {with $received_protocol \
  72               ${if def:tls_cipher {(cipher=$tls_cipher)}}}}\n\t\
  73         ${if def:sender_address \
  74              {(envelope-from $sender_address\
  75               ${if def:authenticated_id \
  76                    {; auth=${quote_local_part:$authenticated_id}} \
  77                    {${if and {{def:authenticated_sender} \
  78                               {match_address{$authenticated_sender} \
  79                                             {*@CONF_master_domain}}} \
  80                          {; auth=${quote_local_part:\
  81                                     ${local_part:\
  82                                       $authenticated_sender}}}}}})\n\t}}\
  83         id $message_exim_id\
  84         ${if def:received_for {\n\tfor $received_for}}
  85
  86 SECTION(global, smtp)m4_dnl
  87 smtp_return_error_details = true
  88 accept_8bitmime = true
  89
  90 SECTION(global, env)m4_dnl
  91 keep_environment =
  92
  93 SECTION(global, process)m4_dnl
  94 extract_addresses_remove_arguments = false
  95 headers_charset = utf-8
  96 qualify_domain = CONF_master_domain
  97 untrusted_set_sender = *
  98 local_from_check = false
  99 local_sender_retain = true
 100
 101 SECTION(global, bounce)m4_dnl
 102 delay_warning = 1h : 24h : 2d
 103
 104 SECTION(global, tls)m4_dnl
 105 tls_certificate = CONF_sysconf_dir/server.certlist
 106 tls_privatekey = CONF_sysconf_dir/server.key
 107 tls_advertise_hosts = ${if exists {CONF_sysconf_dir/server.key} {*}{}}
 108 tls_dhparam = CONF_ca_dir/dh-param-2048.pem
 109 tls_require_ciphers = ${if or {{={$received_port}{CONF_submission_port}} \
 110                                {match_ip {$sender_host_address}{+trusted}}} \
 111                            {CONF_good_ciphers} \
 112                            {CONF_acceptable_ciphers}}
 113 tls_verify_certificates = CONF_ca_dir/ca.cert
 114 tls_verify_hosts = ${if eq{$acl_c_mode}{submission} {} {+allnets}}
 115
 116 DIVERT(null)
 117 ###--------------------------------------------------------------------------
 118 ### Access control lists.
 119
 120 SECTION(global, acl-after)
 121 SECTION(global, acl)m4_dnl
 122 acl_smtp_helo = helo
 123 SECTION(acl, misc)m4_dnl
 124 helo:
 125         ## Check that the caller's claimed identity is actually plausible.
 126         ## This seems like it's a fairly effective filter on spamminess, but
 127         ## it's too blunt a tool.  Rather than reject, add a warning header.
 128         ## Only we can't do this the easy way, so save it up for use in MAIL.
 129         ## Also, we're liable to get a subsequent HELO (e.g., after STARTTLS)
 130         ## and we should only care about the most recent one.
 131         warn     set acl_c_helo_warning = false
 132                 !condition = \
 133                         ${if and {{match_ip {$sender_host_address} \
 134                                             {<; 127.0.0.0/8 ; ::1}} \
 135                                   {match_domain {$sender_helo_name} \
 136                                                 {localhost : +thishost}}}}
 137                 !condition = \
 138                         ${if exists {CONF_sysconf_dir/helo.conf} \
 139                              {${lookup {$sender_helo_name} \
 140                                        partial0-lsearch \
 141                                        {CONF_sysconf_dir/helo.conf} \
 142                                        {${if match_ip \
 143                                              {$sender_host_address} \
 144                                              {<; $value}}}}}}
 145                 !verify = helo
 146                  set acl_c_helo_warning = true
 147
 148         accept
 149
 150 SECTION(global, acl)m4_dnl
 151 acl_not_smtp_start = not_smtp_start
 152 SECTION(acl, misc)m4_dnl
 153 not_smtp_start:
 154         ## Record the user's name.
 155         warn     set acl_c_user = $sender_ident
 156                  set acl_m_user = $sender_ident
 157
 158         ## Done.
 159         accept
 160
 161 SECTION(global, acl)m4_dnl
 162 acl_smtp_mail = mail
 163 SECTION(acl, mail)m4_dnl
 164 mail:
 165
 166         ## If we stashed a warning header about HELO from earlier, we should
 167         ## add it now.  Only don't bother if the client has authenticated
 168         ## successfully for submission (because we can't expect mobile
 169         ## clients to be properly set up knowing their names), or it's one of
 170         ## our own satellites (because they're either properly set up anyway,
 171         ## or satellites using us as a smarthost).
 172         warn     condition = $acl_c_helo_warning
 173                 !condition = ${if eq{$acl_c_mode}{submission}}
 174                 !hosts = +allnets
 175                  WARNING_HEADER(BADHELO,
 176                                 <:Client's HELO doesn't match its IP address.\n\t\
 177                                   helo-name=$sender_helo_name \
 178                                   address=$sender_host_address:>)
 179
 180         ## Always allow the empty sender, so that we can receive bounces.
 181         accept   senders = :
 182
 183         ## Ensure that the sender looks valid.
 184         require  acl = mail_check_sender
 185
 186         ## If this is directly from a client then hack on it for a while.
 187         warn     condition = ${if eq{$acl_c_mode}{submission}}
 188                  control = submission/sender_retain
 189
 190         ## Insist that a local client connect through TLS.
 191         deny     message = Hosts within CONF_master_domain must use TLS
 192                 !condition = ${if eq{$acl_c_mode}{submission}}
 193                  hosts = +allnets
 194                 !encrypted = *
 195
 196         ## Check that a submitted message's sender address is allowable.
 197         require  acl = mail_check_auth
 198
 199 SECTION(acl, mail-tail)m4_dnl
 200         ## And we're done.
 201         accept
 202
 203 SECTION(acl, misc)m4_dnl
 204 mail_check_sender:
 205
 206         ## See whether there's a special exception for this sender domain.
 207         accept   senders = ${LOOKUP_DOMAIN($sender_address_domain,
 208                              {KV(senders, {$value}{})},
 209                              {})}
 210
 211         ## Ensure that the sender is routable.  This is important to prevent
 212         ## undeliverable bounces.
 213         require  message = Invalid sender; \
 214                         ($sender_verify_failure; $acl_verify_message)
 215                  verify = sender
 216
 217         ## We're good, then.
 218         accept
 219
 220 SECTION(global, acl)m4_dnl
 221 acl_smtp_connect = connect
 222 SECTION(acl, connect)m4_dnl
 223 connect:
 224 SECTION(acl, connect-tail)m4_dnl
 225         ## Configure variables according to the submission mode.
 226         warn     acl = check_submission
 227
 228         ## Done.
 229         accept
 230
 231 check_submission:
 232         ## See whether this message needs hacking on.
 233         accept  !hosts = +thishost
 234                 !condition = ${if ={$received_port}{CONF_submission_port}}
 235                  set acl_c_mode = relay
 236
 237         ## Remember to apply submission controls.
 238         warn     set acl_c_mode = submission
 239
 240         ## Done.
 241         accept
 242
 243 SECTION(global, acl)m4_dnl
 244 acl_smtp_rcpt = rcpt
 245 SECTION(acl, rcpt)m4_dnl
 246 rcpt:
 247
 248         ## Reject if the client isn't allowed to relay and the recipient
 249         ## isn't in one of our known domains.
 250         require  message = Relaying not permitted
 251                  acl = check_relay
 252
 253         ## Ensure that the recipient is routable.
 254         require  message = Invalid recipient \
 255                         ($recipient_verify_failure; $acl_verify_message)
 256                  verify = recipient
 257
 258 SECTION(acl, misc)m4_dnl
 259 check_relay:
 260         ## Accept either if the client is allowed to relay through us, or if
 261         ## we're the correct place to send this mail.
 262
 263         ## Known clients and authenticated users are OK.
 264         accept    hosts = CONF_relay_clients
 265         accept    authenticated = *
 266
 267         ## Known domains are OK.
 268         accept    domains = +public
 269
 270         ## Finally, domains in our table are OK, unless they say they aren't.
 271         accept    domains = \
 272                 ${if exists{CONF_sysconf_dir/domains.conf} \
 273                      {partial0-lsearch; CONF_sysconf_dir/domains.conf}}
 274                   condition = DOMKV(service, {$value}{true})
 275
 276         ## Nope, that's not allowed.
 277         deny
 278
 279 SECTION(acl, rcpt-tail)m4_dnl
 280         ## Everything checks out OK: let this one go through.
 281         accept
 282
 283 SECTION(global, acl)m4_dnl
 284 acl_smtp_data = data
 285 SECTION(acl, data)m4_dnl
 286 data:
 287
 288 SECTION(acl, data-tail)m4_dnl
 289         accept
 290
 291 SECTION(global, acl)m4_dnl
 292 acl_smtp_expn = expn_vrfy
 293 acl_smtp_vrfy = expn_vrfy
 294 SECTION(acl, misc)m4_dnl
 295 expn_vrfy:
 296         accept   hosts = +trusted
 297         deny     message = Suck it and see
 298
 299 DIVERT(null)
 300 ###--------------------------------------------------------------------------
 301 ### Verification of sender address.
 302
 303 SECTION(acl, misc)m4_dnl
 304 mail_check_auth:
 305
 306         ## If this isn't a submission then it doesn't need checking.
 307         accept   condition = ${if !eq{$acl_c_mode}{submission}}
 308
 309         ## If the caller hasn't formally authenticated, but this is a
 310         ## loopback connection, then we can trust identd to tell us the right
 311         ## answer.  So we should stash the right name somewhere consistent.
 312         warn     set acl_c_user = $authenticated_id
 313                  hosts = +thishost
 314                 !authenticated = *
 315                  condition = ${if def:sender_ident}
 316                  set acl_c_user = $sender_ident
 317
 318         ## User must be authenticated by now.
 319         deny     message = Sender not authenticated
 320                  condition = ${if !def:acl_c_user}
 321
 322         ## Set the per-message authentication flag, since we now know that
 323         ## there's a sensible value.
 324         warn     set acl_m_user = $acl_c_user
 325
 326         ## All done.
 327         accept
 328
 329 DIVERT(null)
 330 ###--------------------------------------------------------------------------
 331 ### Common options for forwarding routers.
 332
 333 ## We're pretty permissive here.
 334 m4_define(<:FILTER_BASE:>,
 335         <:driver = redirect
 336         modemask = 002
 337         check_owner = false
 338         check_group = false
 339         allow_filter = true
 340         allow_defer = true
 341         allow_fail = true
 342         forbid_blackhole = false
 343         check_ancestor = true:>)
 344
 345 ## Common options for forwarding routers at verification time.
 346 m4_define(<:FILTER_VERIFY:>,
 347         <:verify_only = true
 348         user = CONF_filter_user
 349         forbid_filter_dlfunc = true
 350         forbid_filter_logwrite = true
 351         forbid_filter_perl = true
 352         forbid_filter_readsocket = true
 353         forbid_filter_run = true
 354         file_transport = dummy
 355         directory_transport = dummy
 356         pipe_transport = dummy
 357         reply_transport = dummy:>)
 358
 359 ## Transports for redirection filters.
 360 m4_define(<:FILTER_TRANSPORTS:>,
 361         <:file_transport = mailbox
 362         directory_transport = maildir
 363         pipe_transport = pipe
 364         reply_transport = reply:>)
 365
 366 m4_define(<:FILTER_ROUTER:>,
 367 <:$1_vrf:
 368         $2
 369         FILTER_VERIFY<::>$3
 370 $1:
 371         $2
 372         verify = no
 373         FILTER_TRANSPORTS<::>$4:>)
 374
 375 DIVERT(null)
 376 ###--------------------------------------------------------------------------
 377 ### Common routers.
 378
 379 SECTION(routers, alias)m4_dnl
 380 ## Look up the local part in the address map.
 381 alias:
 382         driver = redirect
 383         allow_fail = true
 384         allow_defer = true
 385         user = CONF_filter_user
 386         FILTER_TRANSPORTS
 387         local_parts = nwildlsearch; CONF_alias_file
 388         data = ${expand:$local_part_data}
 389 SECTION(routers, alias-opts)m4_dnl
 390
 391 DIVERT(null)
 392 ###--------------------------------------------------------------------------
 393 ### Some standard transports.
 394
 395 m4_define(<:USER_DELIVERY:>,
 396         <:delivery_date_add = true
 397         envelope_to_add = true
 398         return_path_add = true:>)
 399
 400 m4_define(<:APPLY_HEADER_CHANGES:>,
 401         <:headers_add = m4_ifelse(<:$1:>, <::>,
 402                 <:$acl_m_hdradd:>,
 403                 <:${if def:acl_m_hdradd{$acl_m_hdradd\n}}\
 404                 $1:>)
 405         headers_remove = m4_ifelse(<:$2:>, <::>,
 406                 <:$acl_m_hdrrm:>,
 407                 <:${if def:acl_m_hdrrm{$acl_m_hdrrm:}}\
 408                 $2:>):>)
 409
 410 SECTION(transports)m4_dnl
 411 ## A standard transport for remote delivery.  By default, try to do TLS, and
 412 ## don't worry too much if it's not very secure: the alternative is sending
 413 ## in plaintext anyway.  But all of this can be overridden from the
 414 ## `domains.conf' file.  Annoyingly, the `tls_dh_min_bits' setting isn't
 415 ## expanded before use, so we can't set it the obvious way.  Instead, encode
 416 ## it into the transport name.  This is very unpleasant, of course.
 417 smtp:
 418         driver = smtp
 419         APPLY_HEADER_CHANGES
 420         tls_require_ciphers = CONF_acceptable_ciphers
 421         tls_dh_min_bits = 508
 422         tls_tempfail_tryclear = true
 423
 424 m4_define(<:SMTP_TRANS_DHBITS:>,
 425         <:driver = smtp
 426         APPLY_HEADER_CHANGES
 427         hosts_try_auth = *
 428         hosts_require_tls = DOMKV(tls-peer-ca, {*}{})
 429         hosts_require_auth = \
 430                 ${if bool {DOMKV(require-auth, {$value}{false})} {*}{}}
 431         tls_certificate = DOMKV(tls-certificate, {${expand:$value}}fail)
 432         tls_privatekey = DOMKV(tls-private-key, {${expand:$value}}fail)
 433         tls_verify_certificates = DOMKV(tls-peer-ca, {${expand:$value}}fail)
 434         tls_require_ciphers = \
 435                 DOMKV(tls-ciphers,
 436                       {${extract {${expand:$value}} \
 437                                  { good = CONF_good_ciphers \
 438                                    any = CONF_acceptable_ciphers } \
 439                                  {$value} \
 440                                  {${expand:$value}}}} \
 441                       {CONF_acceptable_ciphers})
 442         tls_dh_min_bits = $1
 443         tls_tempfail_tryclear = true:>)m4_dnl
 444 smtp_dhbits_512:
 445         SMTP_TRANS_DHBITS(508)
 446 smtp_dhbits_768:
 447         SMTP_TRANS_DHBITS(764)
 448 smtp_dhbits_1024:
 449         SMTP_TRANS_DHBITS(1020)
 450 smtp_dhbits_2048:
 451         SMTP_TRANS_DHBITS(2044)
 452
 453 ## Transport to a local SMTP server; use TLS and perform client
 454 ## authentication.
 455 smtp_local:
 456         driver = smtp
 457         APPLY_HEADER_CHANGES
 458         hosts_require_tls = *
 459         tls_certificate = CONF_sysconf_dir/client.certlist
 460         tls_privatekey = CONF_sysconf_dir/client.key
 461         tls_verify_certificates = CONF_ca_dir/ca.cert
 462         tls_require_ciphers = CONF_good_ciphers
 463         tls_dh_min_bits = 2046
 464         tls_tempfail_tryclear = false
 465         authenticated_sender_force = true
 466         authenticated_sender = \
 467                 ${if def:acl_m_user {$acl_m_user@CONF_master_domain} \
 468                      {${if def:authenticated_sender {$authenticated_sender} \
 469                            fail}}}
 470
 471 ## A standard transport for local delivery.
 472 deliver:
 473         driver = appendfile
 474         APPLY_HEADER_CHANGES
 475         file = /var/mail/$local_part
 476         group = mail
 477         mode = 0600
 478         mode_fail_narrower = false
 479         USER_DELIVERY
 480
 481 ## Transports for user filters.
 482 mailbox:
 483         driver = appendfile
 484         APPLY_HEADER_CHANGES
 485         initgroups = true
 486         USER_DELIVERY
 487
 488 maildir:
 489         driver = appendfile
 490         APPLY_HEADER_CHANGES
 491         maildir_format = true
 492         initgroups = true
 493         USER_DELIVERY
 494
 495 pipe:
 496         driver = pipe
 497         APPLY_HEADER_CHANGES
 498         path = ${if and {{def:home} {exists{$home/bin}}} {$home/bin:} {}}\
 499                 /usr/local/bin:/usr/local/sbin:\
 500                 /usr/bin:/usr/sbin:/bin:/sbin
 501         initgroups = true
 502         umask = 002
 503         return_fail_output = true
 504         log_output = true
 505
 506 ## A special dummy transport for use during address verification.
 507 dummy:
 508         driver = appendfile
 509         file = /dev/null
 510
 511 DIVERT(null)
 512 ###--------------------------------------------------------------------------
 513 ### Retry configuration.
 514
 515 SECTION(retry, default)m4_dnl
 516 ## Default.
 517 *                                       * \
 518         F,2h,15m; G,16h,2h,1.5; F,4d,6h
 519
 520 DIVERT(null)
 521 ###----- That's all, folks --------------------------------------------------