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