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