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