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 chunking_advertise_hosts =
  92
  93 SECTION(global, env)m4_dnl
  94 keep_environment =
  95
  96 SECTION(global, process)m4_dnl
  97 extract_addresses_remove_arguments = false
  98 headers_charset = utf-8
  99 qualify_domain = CONF_master_domain
 100 untrusted_set_sender = *
 101 local_from_check = false
 102 local_sender_retain = true
 103
 104 SECTION(global, bounce)m4_dnl
 105 delay_warning = 1h : 24h : 2d
 106
 107 SECTION(global, tls)m4_dnl
 108 tls_certificate = CONF_sysconf_dir/server.certlist
 109 tls_privatekey = CONF_sysconf_dir/server.key
 110 tls_advertise_hosts = ${if exists {CONF_sysconf_dir/server.key} {*}{}}
 111 tls_dhparam = CONF_ca_dir/dh-param-2048.pem
 112 tls_require_ciphers = ${if or {{={$received_port}{CONF_submission_port}} \
 113                                {match_ip {$sender_host_address}{+trusted}}} \
 114                            {CONF_good_ciphers} \
 115                            {CONF_acceptable_ciphers}}
 116 tls_verify_certificates = CONF_ca_dir/ca.cert
 117 tls_verify_hosts = ${if eq{$acl_c_mode}{submission} {} {+allnets}}
 118
 119 DIVERT(null)
 120 ###--------------------------------------------------------------------------
 121 ### Access control lists.
 122
 123 SECTION(global, acl-after)
 124 SECTION(global, acl)m4_dnl
 125 acl_smtp_helo = helo
 126 SECTION(acl, misc)m4_dnl
 127 helo:
 128         ## Check that the caller's claimed identity is actually plausible.
 129         ## This seems like it's a fairly effective filter on spamminess, but
 130         ## it's too blunt a tool.  Rather than reject, add a warning header.
 131         ## Only we can't do this the easy way, so save it up for use in MAIL.
 132         ## Also, we're liable to get a subsequent HELO (e.g., after STARTTLS)
 133         ## and we should only care about the most recent one.
 134         warn     set acl_c_helo_warning = false
 135                 !condition = \
 136                         ${if and {{match_ip {$sender_host_address} \
 137                                             {<; 127.0.0.0/8 ; ::1}} \
 138                                   {match_domain {$sender_helo_name} \
 139                                                 {localhost : +thishost}}}}
 140                 !condition = \
 141                         ${if exists {CONF_sysconf_dir/helo.conf} \
 142                              {${lookup {$sender_helo_name} \
 143                                        partial0-lsearch \
 144                                        {CONF_sysconf_dir/helo.conf} \
 145                                        {${if match_ip \
 146                                              {$sender_host_address} \
 147                                              {<; $value}}}}}}
 148                 !verify = helo
 149                  set acl_c_helo_warning = true
 150
 151         accept
 152
 153 SECTION(global, acl)m4_dnl
 154 acl_not_smtp_start = not_smtp_start
 155 SECTION(acl, misc)m4_dnl
 156 not_smtp_start:
 157         ## Record the user's name.
 158         warn     set acl_c_user = $sender_ident
 159                  set acl_m_user = $sender_ident
 160
 161         ## Done.
 162         accept
 163
 164 SECTION(global, acl)m4_dnl
 165 acl_smtp_mail = mail
 166 SECTION(acl, mail)m4_dnl
 167 mail:
 168
 169         ## If we stashed a warning header about HELO from earlier, we should
 170         ## add it now.  Only don't bother if the client has authenticated
 171         ## successfully for submission (because we can't expect mobile
 172         ## clients to be properly set up knowing their names), or it's one of
 173         ## our own satellites (because they're either properly set up anyway,
 174         ## or satellites using us as a smarthost).
 175         warn     condition = $acl_c_helo_warning
 176                 !condition = ${if eq{$acl_c_mode}{submission}}
 177                 !hosts = +allnets
 178                  WARNING_HEADER(BADHELO,
 179                                 <:Client's HELO doesn't match its IP address.\n\t\
 180                                   helo-name=$sender_helo_name \
 181                                   address=$sender_host_address:>)
 182
 183         ## Always allow the empty sender, so that we can receive bounces.
 184         accept   senders = :
 185
 186         ## Ensure that the sender looks valid.
 187         require  acl = mail_check_sender
 188
 189         ## If this is directly from a client then hack on it for a while.
 190         warn     condition = ${if eq{$acl_c_mode}{submission}}
 191                  control = submission/sender_retain
 192
 193         ## Insist that a local client connect through TLS.
 194         deny     message = Hosts within CONF_master_domain must use TLS
 195                 !condition = ${if eq{$acl_c_mode}{submission}}
 196                  hosts = +allnets
 197                 !encrypted = *
 198
 199         ## Check that a submitted message's sender address is allowable.
 200         require  acl = mail_check_auth
 201
 202 SECTION(acl, mail-tail)m4_dnl
 203         ## And we're done.
 204         accept
 205
 206 SECTION(acl, misc)m4_dnl
 207 mail_check_sender:
 208
 209         ## See whether there's a special exception for this sender domain.
 210         accept   senders = ${LOOKUP_DOMAIN($sender_address_domain,
 211                              {KV(senders, {$value}{})},
 212                              {})}
 213
 214         ## Ensure that the sender is routable.  This is important to prevent
 215         ## undeliverable bounces.
 216         require  message = Invalid sender; \
 217                         ($sender_verify_failure; $acl_verify_message)
 218                  verify = sender
 219
 220         ## We're good, then.
 221         accept
 222
 223 SECTION(global, acl)m4_dnl
 224 acl_smtp_connect = connect
 225 SECTION(acl, connect)m4_dnl
 226 connect:
 227 SECTION(acl, connect-tail)m4_dnl
 228         ## Configure variables according to the submission mode.
 229         warn     acl = check_submission
 230
 231         ## Done.
 232         accept
 233
 234 check_submission:
 235         ## See whether this message needs hacking on.
 236         accept  !hosts = +thishost
 237                 !condition = ${if ={$received_port}{CONF_submission_port}}
 238                  set acl_c_mode = relay
 239
 240         ## Remember to apply submission controls.
 241         warn     set acl_c_mode = submission
 242
 243         ## Done.
 244         accept
 245
 246 SECTION(global, acl)m4_dnl
 247 acl_smtp_rcpt = rcpt
 248 SECTION(acl, rcpt)m4_dnl
 249 rcpt:
 250
 251         ## Reject if the client isn't allowed to relay and the recipient
 252         ## isn't in one of our known domains.
 253         require  message = Relaying not permitted
 254                  acl = check_relay
 255
 256         ## Ensure that the recipient is routable.
 257         require  message = Invalid recipient \
 258                         ($recipient_verify_failure; $acl_verify_message)
 259                  verify = recipient
 260
 261 SECTION(acl, misc)m4_dnl
 262 check_relay:
 263         ## Accept either if the client is allowed to relay through us, or if
 264         ## we're the correct place to send this mail.
 265
 266         ## Known clients and authenticated users are OK.
 267         accept   hosts = CONF_relay_clients
 268         accept   authenticated = *
 269
 270         ## Known domains are OK.
 271         accept   domains = +public
 272
 273         ## Finally, domains in our table are OK, unless they say they aren't.
 274         accept   domains = \
 275                  ${if exists{CONF_sysconf_dir/domains.conf} \
 276                      {partial0-lsearch; CONF_sysconf_dir/domains.conf}}
 277                  condition = DOMKV(service, {$value}{true})
 278
 279         ## Nope, that's not allowed.
 280         deny
 281
 282 SECTION(acl, rcpt-tail)m4_dnl
 283         ## Everything checks out OK: let this one go through.
 284         accept
 285
 286 SECTION(global, acl)m4_dnl
 287 acl_smtp_data = data
 288 SECTION(acl, data)m4_dnl
 289 data:
 290         ## Don't accept messages with overly-long lines.
 291         deny     message = line length exceeds SMTP permitted maximum: \
 292                         $max_received_linelength > 998
 293                  condition = ${if >{$max_received_linelength}{998}}
 294
 295 SECTION(acl, data-tail)m4_dnl
 296         accept
 297
 298 SECTION(global, acl)m4_dnl
 299 acl_smtp_expn = expn_vrfy
 300 acl_smtp_vrfy = expn_vrfy
 301 SECTION(acl, misc)m4_dnl
 302 expn_vrfy:
 303         accept   hosts = +trusted
 304         deny     message = Suck it and see
 305
 306 DIVERT(null)
 307 ###--------------------------------------------------------------------------
 308 ### Verification of sender address.
 309
 310 SECTION(acl, misc)m4_dnl
 311 mail_check_auth:
 312
 313         ## If this isn't a submission then it doesn't need checking.
 314         accept   condition = ${if !eq{$acl_c_mode}{submission}}
 315
 316         ## If the caller hasn't formally authenticated, but this is a
 317         ## loopback connection, then we can trust identd to tell us the right
 318         ## answer.  So we should stash the right name somewhere consistent.
 319         warn     set acl_c_user = $authenticated_id
 320                  hosts = +thishost
 321                 !authenticated = *
 322                  condition = ${if def:sender_ident}
 323                  set acl_c_user = $sender_ident
 324
 325         ## User must be authenticated by now.
 326         deny     message = Sender not authenticated
 327                  condition = ${if !def:acl_c_user}
 328
 329         ## Set the per-message authentication flag, since we now know that
 330         ## there's a sensible value.
 331         warn     set acl_m_user = $acl_c_user
 332
 333         ## All done.
 334         accept
 335
 336 DIVERT(null)
 337 ###--------------------------------------------------------------------------
 338 ### Common options for forwarding routers.
 339
 340 ## We're pretty permissive here.
 341 m4_define(<:FILTER_BASE:>,
 342         <:driver = redirect
 343         modemask = 002
 344         check_owner = false
 345         check_group = false
 346         allow_filter = true
 347         allow_defer = true
 348         allow_fail = true
 349         forbid_blackhole = false
 350         check_ancestor = true:>)
 351
 352 ## Common options for forwarding routers at verification time.
 353 m4_define(<:FILTER_VERIFY:>,
 354         <:verify_only = true
 355         user = CONF_filter_user
 356         forbid_filter_dlfunc = true
 357         forbid_filter_logwrite = true
 358         forbid_filter_perl = true
 359         forbid_filter_readsocket = true
 360         forbid_filter_run = true
 361         file_transport = dummy
 362         directory_transport = dummy
 363         pipe_transport = dummy
 364         reply_transport = dummy:>)
 365
 366 ## Transports for redirection filters.
 367 m4_define(<:FILTER_TRANSPORTS:>,
 368         <:file_transport = mailbox
 369         directory_transport = maildir
 370         pipe_transport = pipe
 371         reply_transport = reply:>)
 372
 373 m4_define(<:FILTER_ROUTER:>,
 374 <:$1_vrf:
 375         $2
 376         FILTER_VERIFY<::>$3
 377 $1:
 378         $2
 379         verify = no
 380         FILTER_TRANSPORTS<::>$4:>)
 381
 382 DIVERT(null)
 383 ###--------------------------------------------------------------------------
 384 ### Common routers.
 385
 386 SECTION(routers, alias)m4_dnl
 387 ## Look up the local part in the address map.
 388 alias:
 389         driver = redirect
 390         allow_fail = true
 391         allow_defer = true
 392         user = CONF_filter_user
 393         FILTER_TRANSPORTS
 394         local_parts = nwildlsearch; CONF_alias_file
 395         data = ${expand:$local_part_data}
 396 SECTION(routers, alias-opts)m4_dnl
 397
 398 DIVERT(null)
 399 ###--------------------------------------------------------------------------
 400 ### Some standard transports.
 401
 402 m4_define(<:USER_DELIVERY:>,
 403         <:delivery_date_add = true
 404         envelope_to_add = true
 405         return_path_add = true:>)
 406
 407 m4_define(<:APPLY_HEADER_CHANGES:>,
 408         <:headers_add = m4_ifelse(<:$1:>, <::>,
 409                 <:$acl_m_hdradd:>,
 410                 <:${if def:acl_m_hdradd{$acl_m_hdradd\n}}\
 411                 $1:>)
 412         headers_remove = m4_ifelse(<:$2:>, <::>,
 413                 <:$acl_m_hdrrm:>,
 414                 <:${if def:acl_m_hdrrm{$acl_m_hdrrm:}}\
 415                 $2:>):>)
 416
 417 m4_define(<:SMTP_DELIVERY:>,
 418         <:## Prevent sending messages with overly long lines.  The use of
 419         ## `message_size_limit' here is somewhat misleading.
 420         message_size_limit = ${if >{$max_received_linelength}{998}{1}{0}}:>)
 421
 422 SECTION(transports)m4_dnl
 423 ## A standard transport for remote delivery.  By default, try to do TLS, and
 424 ## don't worry too much if it's not very secure: the alternative is sending
 425 ## in plaintext anyway.  But all of this can be overridden from the
 426 ## `domains.conf' file.  Annoyingly, the `tls_dh_min_bits' setting isn't
 427 ## expanded before use, so we can't set it the obvious way.  Instead, encode
 428 ## it into the transport name.  This is very unpleasant, of course.
 429 smtp:
 430         driver = smtp
 431         APPLY_HEADER_CHANGES
 432         tls_require_ciphers = CONF_acceptable_ciphers
 433         tls_dh_min_bits = 508
 434         tls_tempfail_tryclear = true
 435
 436 m4_define(<:SMTP_TRANS_DHBITS:>,
 437         <:driver = smtp
 438         SMTP_DELIVERY
 439         APPLY_HEADER_CHANGES
 440         hosts_try_auth = *
 441         hosts_require_tls = DOMKV(tls-peer-ca, {*}{})
 442         hosts_require_auth = \
 443                 ${if bool {DOMKV(require-auth, {$value}{false})} {*}{}}
 444         tls_certificate = DOMKV(tls-certificate, {${expand:$value}}fail)
 445         tls_privatekey = DOMKV(tls-private-key, {${expand:$value}}fail)
 446         tls_verify_certificates = DOMKV(tls-peer-ca, {${expand:$value}}fail)
 447         tls_require_ciphers = \
 448                 DOMKV(tls-ciphers,
 449                       {${extract {${expand:$value}} \
 450                                  { good = CONF_good_ciphers \
 451                                    any = CONF_acceptable_ciphers } \
 452                                  {$value} \
 453                                  {${expand:$value}}}} \
 454                       {CONF_acceptable_ciphers})
 455         tls_dh_min_bits = $1
 456         tls_tempfail_tryclear = true:>)m4_dnl
 457 smtp_dhbits_512:
 458         SMTP_TRANS_DHBITS(508)
 459 smtp_dhbits_768:
 460         SMTP_TRANS_DHBITS(764)
 461 smtp_dhbits_1024:
 462         SMTP_TRANS_DHBITS(1020)
 463 smtp_dhbits_2048:
 464         SMTP_TRANS_DHBITS(2044)
 465
 466 ## Transport to a local SMTP server; use TLS and perform client
 467 ## authentication.
 468 smtp_local:
 469         driver = smtp
 470         SMTP_DELIVERY
 471         APPLY_HEADER_CHANGES
 472         hosts_require_tls = *
 473         tls_certificate = CONF_sysconf_dir/client.certlist
 474         tls_privatekey = CONF_sysconf_dir/client.key
 475         tls_verify_certificates = CONF_ca_dir/ca.cert
 476         tls_require_ciphers = CONF_good_ciphers
 477         tls_dh_min_bits = 2046
 478         tls_tempfail_tryclear = false
 479         authenticated_sender_force = true
 480         authenticated_sender = \
 481                 ${if def:acl_m_user {$acl_m_user@CONF_master_domain} \
 482                      {${if def:authenticated_sender {$authenticated_sender} \
 483                            fail}}}
 484
 485 ## A standard transport for local delivery.
 486 deliver:
 487         driver = appendfile
 488         APPLY_HEADER_CHANGES
 489         file = /var/mail/$local_part
 490         group = mail
 491         mode = 0600
 492         mode_fail_narrower = false
 493         USER_DELIVERY
 494
 495 ## Transports for user filters.
 496 mailbox:
 497         driver = appendfile
 498         APPLY_HEADER_CHANGES
 499         initgroups = true
 500         USER_DELIVERY
 501
 502 maildir:
 503         driver = appendfile
 504         APPLY_HEADER_CHANGES
 505         maildir_format = true
 506         initgroups = true
 507         USER_DELIVERY
 508
 509 pipe:
 510         driver = pipe
 511         APPLY_HEADER_CHANGES
 512         path = ${if and {{def:home} {exists{$home/bin}}} {$home/bin:} {}}\
 513                 /usr/local/bin:/usr/local/sbin:\
 514                 /usr/bin:/usr/sbin:/bin:/sbin
 515         initgroups = true
 516         umask = 002
 517         return_fail_output = true
 518         log_output = true
 519
 520 ## A special dummy transport for use during address verification.
 521 dummy:
 522         driver = appendfile
 523         file = /dev/null
 524
 525 DIVERT(null)
 526 ###--------------------------------------------------------------------------
 527 ### Retry configuration.
 528
 529 SECTION(retry, default)m4_dnl
 530 ## Default.
 531 *                                       * \
 532         F,2h,15m; G,16h,2h,1.5; F,4d,6h
 533
 534 DIVERT(null)
 535 ###----- That's all, folks --------------------------------------------------