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                  set acl_m_user = $sender_ident
 151
 152         ## Done.
 153         accept
 154
 155 SECTION(global, acl)m4_dnl
 156 acl_smtp_mail = mail
 157 SECTION(acl, mail)m4_dnl
 158 mail:
 159
 160         ## If we stashed a warning header about HELO from earlier, we should
 161         ## add it now.  Only don't bother if the client has authenticated
 162         ## successfully for submission (because we can't expect mobile
 163         ## clients to be properly set up knowing their names), or it's one of
 164         ## our own satellites (because they're either properly set up anyway,
 165         ## or satellites using us as a smarthost).
 166         warn     condition = $acl_c_helo_warning
 167                 !condition = ${if eq{$acl_c_mode}{submission}}
 168                 !hosts = +allnets
 169                  WARNING_HEADER(BADHELO,
 170                                 <:Client's HELO doesn't match its IP address.\n\t\
 171                                   helo-name=$sender_helo_name \
 172                                   address=$sender_host_address:>)
 173
 174         ## Always allow the empty sender, so that we can receive bounces.
 175         accept   senders = :
 176
 177         ## Ensure that the sender looks valid.
 178         require  acl = mail_check_sender
 179
 180         ## If this is directly from a client then hack on it for a while.
 181         warn     condition = ${if eq{$acl_c_mode}{submission}}
 182                  control = submission/sender_retain
 183
 184         ## Insist that a local client connect through TLS.
 185         deny     message = Hosts within CONF_master_domain must use TLS
 186                 !condition = ${if eq{$acl_c_mode}{submission}}
 187                  hosts = +allnets
 188                 !encrypted = *
 189
 190         ## Check that a submitted message's sender address is allowable.
 191         require  acl = mail_check_auth
 192
 193 SECTION(acl, mail-tail)m4_dnl
 194         ## And we're done.
 195         accept
 196
 197 SECTION(acl, misc)m4_dnl
 198 mail_check_sender:
 199
 200         ## See whether there's a special exception for this sender domain.
 201         accept   senders = ${LOOKUP_DOMAIN($sender_address_domain,
 202                              {KV(senders, {$value}{})},
 203                              {})}
 204
 205         ## Ensure that the sender is routable.  This is important to prevent
 206         ## undeliverable bounces.
 207         require  message = Invalid sender; \
 208                         ($sender_verify_failure; $acl_verify_message)
 209                  verify = sender
 210
 211         ## We're good, then.
 212         accept
 213
 214 SECTION(global, acl)m4_dnl
 215 acl_smtp_connect = connect
 216 SECTION(acl, connect)m4_dnl
 217 connect:
 218 SECTION(acl, connect-tail)m4_dnl
 219         ## Configure variables according to the submission mode.
 220         warn     acl = check_submission
 221
 222         ## Done.
 223         accept
 224
 225 check_submission:
 226         ## See whether this message needs hacking on.
 227         accept  !hosts = +thishost
 228                 !condition = ${if ={$received_port}{CONF_submission_port}}
 229                  set acl_c_mode = relay
 230
 231         ## Remember to apply submission controls.
 232         warn     set acl_c_mode = submission
 233
 234         ## Done.
 235         accept
 236
 237 SECTION(global, acl)m4_dnl
 238 acl_smtp_rcpt = rcpt
 239 SECTION(acl, rcpt)m4_dnl
 240 rcpt:
 241
 242         ## Reject if the client isn't allowed to relay and the recipient
 243         ## isn't in one of our known domains.
 244         require  message = Relaying not permitted
 245                  acl = check_relay
 246
 247         ## Ensure that the recipient is routable.
 248         require  message = Invalid recipient \
 249                         ($recipient_verify_failure; $acl_verify_message)
 250                  verify = recipient
 251
 252 SECTION(acl, misc)m4_dnl
 253 check_relay:
 254         ## Accept either if the client is allowed to relay through us, or if
 255         ## we're the correct place to send this mail.
 256
 257         ## Known clients and authenticated users are OK.
 258         accept    hosts = CONF_relay_clients
 259         accept    authenticated = *
 260
 261         ## Known domains are OK.
 262         accept    domains = +public
 263
 264         ## Finally, domains in our table are OK, unless they say they aren't.
 265         accept    domains = \
 266                 ${if exists{CONF_sysconf_dir/domains.conf} \
 267                      {partial0-lsearch; CONF_sysconf_dir/domains.conf}}
 268                   condition = DOMKV(service, {$value}{true})
 269
 270         ## Nope, that's not allowed.
 271         deny
 272
 273 SECTION(acl, rcpt-tail)m4_dnl
 274         ## Everything checks out OK: let this one go through.
 275         accept
 276
 277 SECTION(global, acl)m4_dnl
 278 acl_smtp_data = data
 279 SECTION(acl, data)m4_dnl
 280 data:
 281
 282 SECTION(acl, data-tail)m4_dnl
 283         accept
 284
 285 SECTION(global, acl)m4_dnl
 286 acl_smtp_expn = expn_vrfy
 287 acl_smtp_vrfy = expn_vrfy
 288 SECTION(acl, misc)m4_dnl
 289 expn_vrfy:
 290         accept   hosts = +trusted
 291         deny     message = Suck it and see
 292
 293 DIVERT(null)
 294 ###--------------------------------------------------------------------------
 295 ### Verification of sender address.
 296
 297 SECTION(acl, misc)m4_dnl
 298 mail_check_auth:
 299
 300         ## If this isn't a submission then it doesn't need checking.
 301         accept   condition = ${if !eq{$acl_c_mode}{submission}}
 302
 303         ## If the caller hasn't formally authenticated, but this is a
 304         ## loopback connection, then we can trust identd to tell us the right
 305         ## answer.  So we should stash the right name somewhere consistent.
 306         warn     set acl_c_user = $authenticated_id
 307                  hosts = +thishost
 308                 !authenticated = *
 309                  condition = ${if def:sender_ident}
 310                  set acl_c_user = $sender_ident
 311
 312         ## User must be authenticated by now.
 313         deny     message = Sender not authenticated
 314                  condition = ${if !def:acl_c_user}
 315
 316         ## Set the per-message authentication flag, since we now know that
 317         ## there's a sensible value.
 318         warn     set acl_m_user = $acl_c_user
 319
 320         ## All done.
 321         accept
 322
 323 DIVERT(null)
 324 ###--------------------------------------------------------------------------
 325 ### Common options for forwarding routers.
 326
 327 ## We're pretty permissive here.
 328 m4_define(<:FILTER_BASE:>,
 329         <:driver = redirect
 330         modemask = 002
 331         check_owner = false
 332         check_group = false
 333         allow_filter = true
 334         allow_defer = true
 335         allow_fail = true
 336         forbid_blackhole = false
 337         check_ancestor = true:>)
 338
 339 ## Common options for forwarding routers at verification time.
 340 m4_define(<:FILTER_VERIFY:>,
 341         <:verify_only = true
 342         user = CONF_filter_user
 343         forbid_filter_dlfunc = true
 344         forbid_filter_logwrite = true
 345         forbid_filter_perl = true
 346         forbid_filter_readsocket = true
 347         forbid_filter_run = true
 348         file_transport = dummy
 349         directory_transport = dummy
 350         pipe_transport = dummy
 351         reply_transport = dummy:>)
 352
 353 ## Transports for redirection filters.
 354 m4_define(<:FILTER_TRANSPORTS:>,
 355         <:file_transport = mailbox
 356         directory_transport = maildir
 357         pipe_transport = pipe
 358         reply_transport = reply:>)
 359
 360 m4_define(<:FILTER_ROUTER:>,
 361 <:$1_vrf:
 362         $2
 363         FILTER_VERIFY<::>$3
 364 $1:
 365         $2
 366         verify = no
 367         FILTER_TRANSPORTS<::>$4:>)
 368
 369 DIVERT(null)
 370 ###--------------------------------------------------------------------------
 371 ### Common routers.
 372
 373 SECTION(routers, alias)m4_dnl
 374 ## Look up the local part in the address map.
 375 alias:
 376         driver = redirect
 377         allow_fail = true
 378         allow_defer = true
 379         user = CONF_filter_user
 380         FILTER_TRANSPORTS
 381         local_parts = nwildlsearch; CONF_alias_file
 382         data = ${expand:$local_part_data}
 383 SECTION(routers, alias-opts)m4_dnl
 384
 385 DIVERT(null)
 386 ###--------------------------------------------------------------------------
 387 ### Some standard transports.
 388
 389 m4_define(<:USER_DELIVERY:>,
 390         <:delivery_date_add = true
 391         envelope_to_add = true
 392         return_path_add = true:>)
 393
 394 m4_define(<:APPLY_HEADER_CHANGES:>,
 395         <:headers_add = m4_ifelse(<:$1:>, <::>,
 396                 <:$acl_m_hdradd:>,
 397                 <:${if def:acl_m_hdradd{$acl_m_hdradd\n}}\
 398                 $1:>)
 399         headers_remove = m4_ifelse(<:$2:>, <::>,
 400                 <:$acl_m_hdrrm:>,
 401                 <:${if def:acl_m_hdrrm{$acl_m_hdrrm:}}\
 402                 $2:>):>)
 403
 404 SECTION(transports)m4_dnl
 405 ## A standard transport for remote delivery.  By default, try to do TLS, and
 406 ## don't worry too much if it's not very secure: the alternative is sending
 407 ## in plaintext anyway.  But all of this can be overridden from the
 408 ## `domains.conf' file.  Annoyingly, the `tls_dh_min_bits' setting isn't
 409 ## expanded before use, so we can't set it the obvious way.  Instead, encode
 410 ## it into the transport name.  This is very unpleasant, of course.
 411 smtp:
 412         driver = smtp
 413         APPLY_HEADER_CHANGES
 414         tls_require_ciphers = CONF_acceptable_ciphers
 415         tls_dh_min_bits = 1020
 416         tls_tempfail_tryclear = true
 417
 418 m4_define(<:SMTP_TRANS_DHBITS:>,
 419         <:driver = smtp
 420         APPLY_HEADER_CHANGES
 421         hosts_try_auth = *
 422         hosts_require_tls = DOMKV(tls-peer-ca, {*}{})
 423         hosts_require_auth = \
 424                 ${if bool {DOMKV(require-auth, {$value}{false})} {*}{}}
 425         tls_certificate = DOMKV(tls-certificate, {${expand:$value}}fail)
 426         tls_privatekey = DOMKV(tls-private-key, {${expand:$value}}fail)
 427         tls_verify_certificates = DOMKV(tls-peer-ca, {${expand:$value}}fail)
 428         tls_require_ciphers = \
 429                 DOMKV(tls-ciphers,
 430                       {${extract {${expand:$value}} \
 431                                  { good = CONF_good_ciphers \
 432                                    any = CONF_acceptable_ciphers } \
 433                                  {$value} \
 434                                  {${expand:$value}}}} \
 435                       {CONF_acceptable_ciphers})
 436         tls_dh_min_bits = $1
 437         tls_tempfail_tryclear = true:>)m4_dnl
 438 smtp_dhbits_1024:
 439         SMTP_TRANS_DHBITS(1020)
 440 smtp_dhbits_2048:
 441         SMTP_TRANS_DHBITS(2046)
 442
 443 ## Transport to a local SMTP server; use TLS and perform client
 444 ## authentication.
 445 smtp_local:
 446         driver = smtp
 447         APPLY_HEADER_CHANGES
 448         hosts_require_tls = *
 449         tls_certificate = CONF_sysconf_dir/client.certlist
 450         tls_privatekey = CONF_sysconf_dir/client.key
 451         tls_verify_certificates = CONF_ca_dir/ca.cert
 452         tls_require_ciphers = CONF_good_ciphers
 453         tls_dh_min_bits = 2046
 454         tls_tempfail_tryclear = false
 455         authenticated_sender = ${if def:authenticated_id \
 456                                     {$authenticated_id@CONF_master_domain} \
 457                                     fail}
 458
 459 ## A standard transport for local delivery.
 460 deliver:
 461         driver = appendfile
 462         APPLY_HEADER_CHANGES
 463         file = /var/mail/$local_part
 464         group = mail
 465         mode = 0600
 466         mode_fail_narrower = false
 467         USER_DELIVERY
 468
 469 ## Transports for user filters.
 470 mailbox:
 471         driver = appendfile
 472         APPLY_HEADER_CHANGES
 473         initgroups = true
 474         USER_DELIVERY
 475
 476 maildir:
 477         driver = appendfile
 478         APPLY_HEADER_CHANGES
 479         maildir_format = true
 480         initgroups = true
 481         USER_DELIVERY
 482
 483 pipe:
 484         driver = pipe
 485         APPLY_HEADER_CHANGES
 486         path = ${if and {{def:home} {exists{$home/bin}}} {$home/bin:} {}}\
 487                 /usr/local/bin:/usr/local/sbin:\
 488                 /usr/bin:/usr/sbin:/bin:/sbin
 489         initgroups = true
 490         umask = 002
 491         return_fail_output = true
 492         log_output = true
 493
 494 ## A special dummy transport for use during address verification.
 495 dummy:
 496         driver = appendfile
 497         file = /dev/null
 498
 499 DIVERT(null)
 500 ###--------------------------------------------------------------------------
 501 ### Retry configuration.
 502
 503 SECTION(retry, default)m4_dnl
 504 ## Default.
 505 *                                       * \
 506         F,2h,15m; G,16h,2h,1.5; F,4d,6h
 507
 508 DIVERT(null)
 509 ###----- That's all, folks --------------------------------------------------