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