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