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