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 rfc1413_hosts = *
  63 rfc1413_query_timeout = 10s
  64 received_header_text = Received: \
  65         ${if def:sender_rcvhost \
  66              {from $sender_rcvhost\n\t} \
  67              {${if def:sender_ident \
  68                    {from ${quote_local_part:$sender_ident} }}}}\
  69         by $primary_hostname \
  70         (Exim $version_number)\
  71         ${if def:tls_cipher {\n\t} { }}\
  72         ${if def:received_protocol \
  73              {with $received_protocol \
  74               ${if def:tls_cipher {(cipher=$tls_cipher)}}}}\n\t\
  75         ${if def:sender_address \
  76              {(envelope-from $sender_address\
  77               ${if def:authenticated_id \
  78                    {; auth=${quote_local_part:$authenticated_id}} \
  79                    {${if and {{def:authenticated_sender} \
  80                               {match_address{$authenticated_sender} \
  81                                             {*@CONF_master_domain}}} \
  82                          {; auth=${quote_local_part:\
  83                                     ${local_part:\
  84                                       $authenticated_sender}}}}}})\n\t}}\
  85         id $message_exim_id\
  86         ${if def:received_for {\n\tfor $received_for}}
  87
  88 SECTION(global, smtp)m4_dnl
  89 smtp_return_error_details = true
  90 accept_8bitmime = true
  91
  92 SECTION(global, env)m4_dnl
  93 keep_environment =
  94
  95 SECTION(global, process)m4_dnl
  96 extract_addresses_remove_arguments = false
  97 headers_charset = utf-8
  98 qualify_domain = CONF_master_domain
  99 untrusted_set_sender = *
 100 local_from_check = false
 101 local_sender_retain = true
 102
 103 SECTION(global, bounce)m4_dnl
 104 delay_warning = 1h : 24h : 2d
 105
 106 SECTION(global, tls)m4_dnl
 107 tls_certificate = CONF_sysconf_dir/server.certlist
 108 tls_privatekey = CONF_sysconf_dir/server.key
 109 tls_advertise_hosts = ${if exists {CONF_sysconf_dir/server.key} {*}{}}
 110 tls_dhparam = CONF_ca_dir/dh-param-2048.pem
 111 tls_require_ciphers = ${if or {{={$received_port}{CONF_submission_port}} \
 112                                {match_ip {$sender_host_address}{+trusted}}} \
 113                            {CONF_good_ciphers} \
 114                            {CONF_acceptable_ciphers}}
 115 tls_verify_certificates = CONF_ca_dir/ca.cert
 116 tls_verify_hosts = ${if eq{$acl_c_mode}{submission} {} {+allnets}}
 117
 118 DIVERT(null)
 119 ###--------------------------------------------------------------------------
 120 ### Access control lists.
 121
 122 SECTION(global, acl-after)
 123 SECTION(global, acl)m4_dnl
 124 acl_smtp_helo = helo
 125 SECTION(acl, misc)m4_dnl
 126 helo:
 127         ## Check that the caller's claimed identity is actually plausible.
 128         ## This seems like it's a fairly effective filter on spamminess, but
 129         ## it's too blunt a tool.  Rather than reject, add a warning header.
 130         ## Only we can't do this the easy way, so save it up for use in MAIL.
 131         ## Also, we're liable to get a subsequent HELO (e.g., after STARTTLS)
 132         ## and we should only care about the most recent one.
 133         warn     set acl_c_helo_warning = false
 134                 !condition = \
 135                         ${if and {{match_ip {$sender_host_address} \
 136                                             {<; 127.0.0.0/8 ; ::1}} \
 137                                   {match_domain {$sender_helo_name} \
 138                                                 {localhost : +thishost}}}}
 139                 !condition = \
 140                         ${if exists {CONF_sysconf_dir/helo.conf} \
 141                              {${lookup {$sender_helo_name} \
 142                                        partial0-lsearch \
 143                                        {CONF_sysconf_dir/helo.conf} \
 144                                        {${if match_ip \
 145                                              {$sender_host_address} \
 146                                              {<; $value}}}}}}
 147                 !verify = helo
 148                  set acl_c_helo_warning = true
 149
 150         accept
 151
 152 SECTION(global, acl)m4_dnl
 153 acl_not_smtp_start = not_smtp_start
 154 SECTION(acl, misc)m4_dnl
 155 not_smtp_start:
 156         ## Record the user's name.
 157         warn     set acl_c_user = $sender_ident
 158                  set acl_m_user = $sender_ident
 159
 160         ## Done.
 161         accept
 162
 163 SECTION(global, acl)m4_dnl
 164 acl_smtp_mail = mail
 165 SECTION(acl, mail)m4_dnl
 166 mail:
 167
 168         ## If we stashed a warning header about HELO from earlier, we should
 169         ## add it now.  Only don't bother if the client has authenticated
 170         ## successfully for submission (because we can't expect mobile
 171         ## clients to be properly set up knowing their names), or it's one of
 172         ## our own satellites (because they're either properly set up anyway,
 173         ## or satellites using us as a smarthost).
 174         warn     condition = $acl_c_helo_warning
 175                 !condition = ${if eq{$acl_c_mode}{submission}}
 176                 !hosts = +allnets
 177                  WARNING_HEADER(BADHELO,
 178                                 <:Client's HELO doesn't match its IP address.\n\t\
 179                                   helo-name=$sender_helo_name \
 180                                   address=$sender_host_address:>)
 181
 182         ## Always allow the empty sender, so that we can receive bounces.
 183         accept   senders = :
 184
 185         ## Ensure that the sender looks valid.
 186         require  acl = mail_check_sender
 187
 188         ## If this is directly from a client then hack on it for a while.
 189         warn     condition = ${if eq{$acl_c_mode}{submission}}
 190                  control = submission/sender_retain
 191
 192         ## Insist that a local client connect through TLS.
 193         deny     message = Hosts within CONF_master_domain must use TLS
 194                 !condition = ${if eq{$acl_c_mode}{submission}}
 195                  hosts = +allnets
 196                 !encrypted = *
 197
 198         ## Check that a submitted message's sender address is allowable.
 199         require  acl = mail_check_auth
 200
 201 SECTION(acl, mail-tail)m4_dnl
 202         ## And we're done.
 203         accept
 204
 205 SECTION(acl, misc)m4_dnl
 206 mail_check_sender:
 207
 208         ## See whether there's a special exception for this sender domain.
 209         accept   senders = ${LOOKUP_DOMAIN($sender_address_domain,
 210                              {KV(senders, {$value}{})},
 211                              {})}
 212
 213         ## Ensure that the sender is routable.  This is important to prevent
 214         ## undeliverable bounces.
 215         require  message = Invalid sender; \
 216                         ($sender_verify_failure; $acl_verify_message)
 217                  verify = sender
 218
 219         ## We're good, then.
 220         accept
 221
 222 SECTION(global, acl)m4_dnl
 223 acl_smtp_connect = connect
 224 SECTION(acl, connect)m4_dnl
 225 connect:
 226 SECTION(acl, connect-tail)m4_dnl
 227         ## Configure variables according to the submission mode.
 228         warn     acl = check_submission
 229
 230         ## Done.
 231         accept
 232
 233 check_submission:
 234         ## See whether this message needs hacking on.
 235         accept  !hosts = +thishost
 236                 !condition = ${if ={$received_port}{CONF_submission_port}}
 237                  set acl_c_mode = relay
 238
 239         ## Remember to apply submission controls.
 240         warn     set acl_c_mode = submission
 241
 242         ## Done.
 243         accept
 244
 245 SECTION(global, acl)m4_dnl
 246 acl_smtp_rcpt = rcpt
 247 SECTION(acl, rcpt)m4_dnl
 248 rcpt:
 249
 250         ## Reject if the client isn't allowed to relay and the recipient
 251         ## isn't in one of our known domains.
 252         require  message = Relaying not permitted
 253                  acl = check_relay
 254
 255         ## Ensure that the recipient is routable.
 256         require  message = Invalid recipient \
 257                         ($recipient_verify_failure; $acl_verify_message)
 258                  verify = recipient
 259
 260 SECTION(acl, misc)m4_dnl
 261 check_relay:
 262         ## Accept either if the client is allowed to relay through us, or if
 263         ## we're the correct place to send this mail.
 264
 265         ## Known clients and authenticated users are OK.
 266         accept    hosts = CONF_relay_clients
 267         accept    authenticated = *
 268
 269         ## Known domains are OK.
 270         accept    domains = +public
 271
 272         ## Finally, domains in our table are OK, unless they say they aren't.
 273         accept    domains = \
 274                 ${if exists{CONF_sysconf_dir/domains.conf} \
 275                      {partial0-lsearch; CONF_sysconf_dir/domains.conf}}
 276                   condition = DOMKV(service, {$value}{true})
 277
 278         ## Nope, that's not allowed.
 279         deny
 280
 281 SECTION(acl, rcpt-tail)m4_dnl
 282         ## Everything checks out OK: let this one go through.
 283         accept
 284
 285 SECTION(global, acl)m4_dnl
 286 acl_smtp_data = data
 287 SECTION(acl, data)m4_dnl
 288 data:
 289
 290 SECTION(acl, data-tail)m4_dnl
 291         accept
 292
 293 SECTION(global, acl)m4_dnl
 294 acl_smtp_expn = expn_vrfy
 295 acl_smtp_vrfy = expn_vrfy
 296 SECTION(acl, misc)m4_dnl
 297 expn_vrfy:
 298         accept   hosts = +trusted
 299         deny     message = Suck it and see
 300
 301 DIVERT(null)
 302 ###--------------------------------------------------------------------------
 303 ### Verification of sender address.
 304
 305 SECTION(acl, misc)m4_dnl
 306 mail_check_auth:
 307
 308         ## If this isn't a submission then it doesn't need checking.
 309         accept   condition = ${if !eq{$acl_c_mode}{submission}}
 310
 311         ## If the caller hasn't formally authenticated, but this is a
 312         ## loopback connection, then we can trust identd to tell us the right
 313         ## answer.  So we should stash the right name somewhere consistent.
 314         warn     set acl_c_user = $authenticated_id
 315                  hosts = +thishost
 316                 !authenticated = *
 317                  condition = ${if def:sender_ident}
 318                  set acl_c_user = $sender_ident
 319
 320         ## User must be authenticated by now.
 321         deny     message = Sender not authenticated
 322                  condition = ${if !def:acl_c_user}
 323
 324         ## Set the per-message authentication flag, since we now know that
 325         ## there's a sensible value.
 326         warn     set acl_m_user = $acl_c_user
 327
 328         ## All done.
 329         accept
 330
 331 DIVERT(null)
 332 ###--------------------------------------------------------------------------
 333 ### Common options for forwarding routers.
 334
 335 ## We're pretty permissive here.
 336 m4_define(<:FILTER_BASE:>,
 337         <:driver = redirect
 338         modemask = 002
 339         check_owner = false
 340         check_group = false
 341         allow_filter = true
 342         allow_defer = true
 343         allow_fail = true
 344         forbid_blackhole = false
 345         check_ancestor = true:>)
 346
 347 ## Common options for forwarding routers at verification time.
 348 m4_define(<:FILTER_VERIFY:>,
 349         <:verify_only = true
 350         user = CONF_filter_user
 351         forbid_filter_dlfunc = true
 352         forbid_filter_logwrite = true
 353         forbid_filter_perl = true
 354         forbid_filter_readsocket = true
 355         forbid_filter_run = true
 356         file_transport = dummy
 357         directory_transport = dummy
 358         pipe_transport = dummy
 359         reply_transport = dummy:>)
 360
 361 ## Transports for redirection filters.
 362 m4_define(<:FILTER_TRANSPORTS:>,
 363         <:file_transport = mailbox
 364         directory_transport = maildir
 365         pipe_transport = pipe
 366         reply_transport = reply:>)
 367
 368 m4_define(<:FILTER_ROUTER:>,
 369 <:$1_vrf:
 370         $2
 371         FILTER_VERIFY<::>$3
 372 $1:
 373         $2
 374         verify = no
 375         FILTER_TRANSPORTS<::>$4:>)
 376
 377 DIVERT(null)
 378 ###--------------------------------------------------------------------------
 379 ### Common routers.
 380
 381 SECTION(routers, alias)m4_dnl
 382 ## Look up the local part in the address map.
 383 alias:
 384         driver = redirect
 385         allow_fail = true
 386         allow_defer = true
 387         user = CONF_filter_user
 388         FILTER_TRANSPORTS
 389         local_parts = nwildlsearch; CONF_alias_file
 390         data = ${expand:$local_part_data}
 391 SECTION(routers, alias-opts)m4_dnl
 392
 393 DIVERT(null)
 394 ###--------------------------------------------------------------------------
 395 ### Some standard transports.
 396
 397 m4_define(<:USER_DELIVERY:>,
 398         <:delivery_date_add = true
 399         envelope_to_add = true
 400         return_path_add = true:>)
 401
 402 m4_define(<:APPLY_HEADER_CHANGES:>,
 403         <:headers_add = m4_ifelse(<:$1:>, <::>,
 404                 <:$acl_m_hdradd:>,
 405                 <:${if def:acl_m_hdradd{$acl_m_hdradd\n}}\
 406                 $1:>)
 407         headers_remove = m4_ifelse(<:$2:>, <::>,
 408                 <:$acl_m_hdrrm:>,
 409                 <:${if def:acl_m_hdrrm{$acl_m_hdrrm:}}\
 410                 $2:>):>)
 411
 412 SECTION(transports)m4_dnl
 413 ## A standard transport for remote delivery.  By default, try to do TLS, and
 414 ## don't worry too much if it's not very secure: the alternative is sending
 415 ## in plaintext anyway.  But all of this can be overridden from the
 416 ## `domains.conf' file.  Annoyingly, the `tls_dh_min_bits' setting isn't
 417 ## expanded before use, so we can't set it the obvious way.  Instead, encode
 418 ## it into the transport name.  This is very unpleasant, of course.
 419 smtp:
 420         driver = smtp
 421         APPLY_HEADER_CHANGES
 422         tls_require_ciphers = CONF_acceptable_ciphers
 423         tls_dh_min_bits = 508
 424         tls_tempfail_tryclear = true
 425
 426 m4_define(<:SMTP_TRANS_DHBITS:>,
 427         <:driver = smtp
 428         APPLY_HEADER_CHANGES
 429         hosts_try_auth = *
 430         hosts_require_tls = DOMKV(tls-peer-ca, {*}{})
 431         hosts_require_auth = \
 432                 ${if bool {DOMKV(require-auth, {$value}{false})} {*}{}}
 433         tls_certificate = DOMKV(tls-certificate, {${expand:$value}}fail)
 434         tls_privatekey = DOMKV(tls-private-key, {${expand:$value}}fail)
 435         tls_verify_certificates = DOMKV(tls-peer-ca, {${expand:$value}}fail)
 436         tls_require_ciphers = \
 437                 DOMKV(tls-ciphers,
 438                       {${extract {${expand:$value}} \
 439                                  { good = CONF_good_ciphers \
 440                                    any = CONF_acceptable_ciphers } \
 441                                  {$value} \
 442                                  {${expand:$value}}}} \
 443                       {CONF_acceptable_ciphers})
 444         tls_dh_min_bits = $1
 445         tls_tempfail_tryclear = true:>)m4_dnl
 446 smtp_dhbits_512:
 447         SMTP_TRANS_DHBITS(508)
 448 smtp_dhbits_768:
 449         SMTP_TRANS_DHBITS(764)
 450 smtp_dhbits_1024:
 451         SMTP_TRANS_DHBITS(1020)
 452 smtp_dhbits_2048:
 453         SMTP_TRANS_DHBITS(2044)
 454
 455 ## Transport to a local SMTP server; use TLS and perform client
 456 ## authentication.
 457 smtp_local:
 458         driver = smtp
 459         APPLY_HEADER_CHANGES
 460         hosts_require_tls = *
 461         tls_certificate = CONF_sysconf_dir/client.certlist
 462         tls_privatekey = CONF_sysconf_dir/client.key
 463         tls_verify_certificates = CONF_ca_dir/ca.cert
 464         tls_require_ciphers = CONF_good_ciphers
 465         tls_dh_min_bits = 2046
 466         tls_tempfail_tryclear = false
 467         authenticated_sender_force = true
 468         authenticated_sender = \
 469                 ${if def:acl_m_user {$acl_m_user@CONF_master_domain} \
 470                      {${if def:authenticated_sender {$authenticated_sender} \
 471                            fail}}}
 472
 473 ## A standard transport for local delivery.
 474 deliver:
 475         driver = appendfile
 476         APPLY_HEADER_CHANGES
 477         file = /var/mail/$local_part
 478         group = mail
 479         mode = 0600
 480         mode_fail_narrower = false
 481         USER_DELIVERY
 482
 483 ## Transports for user filters.
 484 mailbox:
 485         driver = appendfile
 486         APPLY_HEADER_CHANGES
 487         initgroups = true
 488         USER_DELIVERY
 489
 490 maildir:
 491         driver = appendfile
 492         APPLY_HEADER_CHANGES
 493         maildir_format = true
 494         initgroups = true
 495         USER_DELIVERY
 496
 497 pipe:
 498         driver = pipe
 499         APPLY_HEADER_CHANGES
 500         path = ${if and {{def:home} {exists{$home/bin}}} {$home/bin:} {}}\
 501                 /usr/local/bin:/usr/local/sbin:\
 502                 /usr/bin:/usr/sbin:/bin:/sbin
 503         initgroups = true
 504         umask = 002
 505         return_fail_output = true
 506         log_output = true
 507
 508 ## A special dummy transport for use during address verification.
 509 dummy:
 510         driver = appendfile
 511         file = /dev/null
 512
 513 DIVERT(null)
 514 ###--------------------------------------------------------------------------
 515 ### Retry configuration.
 516
 517 SECTION(retry, default)m4_dnl
 518 ## Default.
 519 *                                       * \
 520         F,2h,15m; G,16h,2h,1.5; F,4d,6h
 521
 522 DIVERT(null)
 523 ###----- That's all, folks --------------------------------------------------