servers/mermet/postfix.nix

   1 { pkgs, lib, config, ... }:
   2 let
   3   inherit (builtins) attrNames readFile toPath;
   4   inherit (builtins.extraBuiltins) pass;
   5   inherit (lib) types;
   6   inherit (pkgs.lib) loadFile unlines unwords unlinesAttrs;
   7   inherit (config) networking;
   8   inherit (config.services) postfix dovecot2 openldap;
   9
  10   submissionHeaderCleanupRules = pkgs.writeText "submission_header_cleanup_rules" ''
  11     # Removes sensitive headers from mails handed in via the submission or smtps port.
  12     # See https://thomas-leister.de/mailserver-debian-stretch/
  13     # Uses "pcre" style regex.
  14
  15     /^Received:/         IGNORE
  16     /^User-Agent:/       IGNORE
  17     /^X-Enigmail:/       IGNORE
  18     /^X-Mailer:/         IGNORE
  19     /^X-Originating-IP:/ IGNORE
  20   '';
  21 in
  22 {
  23 systemd.services.postfix.after = [
  24   "openldap.service"
  25   "postfix.${networking.domainBase}.key.pem-key.service"
  26 ];
  27 deployment.keys = {
  28   "postfix.${networking.domainBase}.key.pem" = {
  29     text        = pass "x509/${networking.domainBase}/key.pem";
  30     user        = postfix.user;
  31     group       = "root";
  32     destDir     = "/run/keys/";
  33     permissions = "0400"; # WARNING: not enforced when deployment.storeKeysOnMachine = true
  34   };
  35 };
  36 services.postfix = {
  37   enable = true;
  38   #hostname = networking.domain;
  39   #domain = "localdomain";
  40   networksStyle = "host";
  41   #mapFiles."valias" = toFile "valias" (unlines (all_valiases_postfix ++ catchAllPostfix));
  42   # See https://blog.grimneko.de/2011/12/24/a-bunch-of-tips-for-improving-your-postfix-setup/
  43   # for details on how this file looks. By using the same file as valias,
  44   # every alias is uniquely owned by its user.
  45   # The user's own address is already in all_valiases_postfix.
  46   #mapFiles."vaccounts" = toFile "vaccounts" (unlines all_valiases_postfix);
  47   mapFiles."virtual_alias_maps" = pkgs.writeText "virtual_alias_maps"
  48     (unlinesAttrs
  49      (from: to: "${from} ${unwords to}")
  50      postfix.aliases);
  51   mapFiles."ldap-virtual_alias_maps.cf" = pkgs.writeText "ldap-virtual_alias_maps.cf" ''
  52     version          = 3
  53     debuglevel       = 0
  54     server_host      = ldapi://
  55     bind             = sasl
  56     sasl_mechs       = EXTERNAL
  57     search_base      = ou=posix,${openldap.domainSuffix}
  58     scope            = sub
  59     dereference      = 0
  60     query_filter     = (&(mailAlias=%s)(mailEnabled=TRUE))
  61     result_format    = %s
  62     result_attribute = mail
  63   '';
  64   mapFiles."ldap-forward.cf" = pkgs.writeText "ldap-forward.cf" ''
  65     version          = 3
  66     debuglevel       = 0
  67     server_host      = ldapi://
  68     bind             = sasl
  69     sasl_mechs       = EXTERNAL
  70     search_base      = ou=posix,${openldap.domainSuffix}
  71     scope            = sub
  72     dereference      = 0
  73     query_filter     = (&(mail=%s)(mailEnabled=TRUE))
  74     result_format    = %s
  75     result_attribute = mailForwardingAddress
  76   '';
  77   sslCert = loadFile (../../../sec/openssl + "/${networking.domainBase}/cert.self-signed.pem");
  78   sslKey = "/run/keys/postfix.${networking.domainBase}.key.pem";
  79   #enableSubmission = true;
  80   #enableSmtp = true;
  81   destination = [
  82     "localhost"
  83     "localhost.localdomain"
  84     networking.hostName
  85     "${networking.hostName}.localdomain"
  86   ];
  87   networks = [
  88     "127.0.0.0/8"
  89     "[::1]/128"
  90   ];
  91   recipientDelimiter = "+";
  92   config = {
  93     # Appending .domain is the MUA's job
  94     append_dot_mydomain = false;
  95     # No console bell on new mail
  96     biff = false;
  97     body_checks = "";
  98     #content_filter = "amavisfeed:[127.0.0.1]:10024";
  99     #debug_peer_level = 4;
 100     #debug_peer_list = ".$myhostname";
 101     default_extra_recipient_limit = "5000";
 102     # Uncomment the next line to generate "delayed mail" warnings
 103     #delay_warning_time = "4h";
 104     # Stops some techniques used to harvest email addresses
 105     disable_vrfy_command = true;
 106     duplicate_filter_limit = "5000";
 107     enable_long_queue_ids = false;
 108     # Pass unexisting $mydestination recipients to dovecot
 109     fallback_transport = "lmtp:unix:private/dovecot-lmtp";
 110     forward_path = [
 111       ''$home/.forward''${recipient_delimiter}''${extension}''
 112       "$home/.forward"
 113     ];
 114     #header_checks = "regexp:/var/lib/postfix/conf/header_checks";
 115     #inet_interfaces = "all";
 116     line_length_limit = "2048";
 117
 118     # Let $fallback_transport check existence of recipients
 119     local_recipient_maps = "";
 120     #mail_spool_directory = "/var/spool/mail";
 121       # NOTE: nixpkgs's default
 122     #local_header_rewrite_clients = "";
 123     #home_mailbox = "Maildir/";
 124     #mailbox_command = ''
 125     #  ${pkgs.procmail}/bin/procmail -t -a "$SENDER" -a "$RECIPIENT" -a "$USER" -a "$EXTENSION" -a "$DOMAIN" -a "$ORIGINAL_RECIPIENT" "$HOME/.procmailrc"
 126     #'';
 127     mailbox_size_limit = "204800000";
 128
 129     masquerade_classes = [ "envelope_sender" "header_sender" "header_recipient" ];
 130     masquerade_domains = "";
 131     masquerade_exceptions = "root";
 132     maximal_queue_lifetime = "5d";
 133     message_size_limit = "20480000";
 134     mime_header_checks = "";
 135     milter_header_checks = "";
 136     nested_header_checks = "";
 137     #non_smtpd_milters = "";
 138     parent_domain_matches_subdomains = [
 139       #"debug_peer_list"
 140       #"fast_flush_domains"
 141       #"mynetworks"
 142       #"permit_mx_backup_networks"
 143       #"qmqpd_authorized_clients"
 144       #"smtpd_access_maps"
 145     ];
 146     permit_mx_backup_networks = "";
 147     #policy-spf_time_limit = "3600s";
 148     propagate_unmatched_extensions = [ "canonical" "virtual" "alias" ];
 149     queue_minfree = "0";
 150     #receive_override_options = "no_address_mappings";
 151       # no_unknown_recipient_checks
 152       #         Do not try to reject unknown recipients (SMTP server only).
 153       #         This is typically specified AFTER an external content filter.
 154       # no_address_mappings
 155       #         Disable canonical address mapping, virtual alias map expansion,
 156       #         address masquerading, and automatic BCC (blind carbon-copy) recipients.
 157       #         This is typically specified BEFORE an external content filter (eg. amavis).
 158       # no_header_body_checks
 159       #         Disable header/body_checks. This is typically specified AFTER
 160       #         an external content filter.
 161       # no_milters
 162       #         Disable Milter (mail filter) applications.
 163       #         This is typically specified AFTER an external content filter.
 164     # Parse the extension in email address, eg. contact+extension@
 165     relayhost = "";
 166     #relay_clientcerts = hash:/var/lib/postfix/conf/relay_clientcerts
 167     # This is where to put backup MX domains
 168     relay_domains = "$mydestination";
 169     relay_recipient_maps = "";
 170     smtp_body_checks = "";
 171     #smtp_cname_overrides_servername = false;
 172     smtp_connect_timeout = "60s";
 173     #smtp_header_checks = "regexp:/var/lib/postfix/smtp_header_checks";
 174     smtp_mime_header_checks = "";
 175     smtp_nested_header_checks = "";
 176     smtp_tls_exclude_ciphers = [ "ADH" "MD5" "CAMELLIA" "SEED" "3DES" "DES" "RC4" "eNULL" "aNULL" ];
 177     #smtp_tls_fingerprint_digest = "sha1";
 178     smtp_tls_loglevel = "1";
 179     #smtp_tls_note_starttls_offer = true;
 180     #smtp_tls_policy_maps = "hash:/var/lib/postfix/conf/tls_policy";
 181     # Only allow TLSv* protocols
 182     smtp_tls_protocols = [ "!SSLv2" "!SSLv3" ];
 183     smtp_tls_scert_verifydepth = "5";
 184     #smtp_tls_secure_cert_match = [ "nexthop" "dot-nexthop" ];
 185     smtp_tls_security_level = "may";
 186     smtp_tls_session_cache_database = "btree:$data_directory/smtp_tls_session_cache";
 187     #smtp_tls_session_cache_timeout = "3600s";
 188     #smtp_tls_verify_cert_match = "hostname";
 189     # Useful to test restrictions
 190     smtpd_authorized_xclient_hosts = "127.0.0.1";
 191     smtpd_banner = "${networking.hostName} ESMTP $mail_name (NixOS)";
 192     smtpd_client_connection_count_limit = "50";
 193     smtpd_client_connection_rate_limit = "0";
 194     smtpd_client_event_limit_exceptions = "$mynetworks";
 195     smtpd_client_message_rate_limit = "0";
 196     smtpd_client_new_tls_session_rate_limit = "0";
 197     smtpd_client_port_logging = false;
 198     smtpd_client_recipient_rate_limit = "0";
 199     smtpd_client_restrictions = [
 200       #"check_client_access hash:/var/lib/postfix/conf/client_blacklist"
 201     ];
 202     smtpd_data_restrictions = [
 203       "reject_unauth_pipelining"
 204         # Force the smtp client to wait OK before sending
 205       "permit"
 206     ];
 207     # Disable opportunistic encryption
 208     smtpd_discard_ehlo_keywords = "starttls";
 209     #smtpd_end_of_data_restrictions = "";
 210     # Ban 5 sec on error
 211     smtpd_error_sleep_time = "5";
 212     smtpd_helo_required = true;
 213     smtpd_helo_restrictions = [
 214       "reject_invalid_helo_hostname"
 215       "reject_non_fqdn_helo_hostname"
 216       #"reject_unknown_helo_hostname"
 217         # May be useful to fight spam
 218       "permit"
 219     ];
 220     #smtpd_milters = "";
 221     smtpd_peername_lookup = true;
 222     smtpd_recipient_limit = "5000";
 223     smtpd_recipient_overshoot_limit = "5000";
 224     smtpd_recipient_restrictions = [
 225       "reject_non_fqdn_recipient"
 226       #"reject_invalid_hostname"
 227       "reject_unknown_recipient_domain"
 228       #"reject_non_fqdn_sender"
 229       "reject_unauth_pipelining"
 230       #"check_policy_service inet:localhost:12340"
 231       # check quota
 232       "permit_mynetworks"
 233       #"permit_tls_clientcerts"
 234       "permit_sasl_authenticated"
 235       "reject_unverified_recipient"
 236         # $fallback_transport is responsible of checking the existence of the recipient
 237         # WARNING: verify(8) has a cache, dumpable if verify(8) is stopped, with:
 238         # postmap -s btree:/var/lib/postfix/data/verify_cache
 239       # Bypass SPF check and postgrey if the recipient is not for us or someone in backup_mx
 240       "reject_unauth_destination"
 241       # Check SPF
 242       #"check_policy_service unix:private/spfcheck"
 243       # Greylisting using postgrey
 244       #"check_policy_service unix:${postgrey.socket.path}"
 245       "permit_auth_destination"
 246       "reject"
 247       #"reject_unknown_sender_domain"
 248         # Maybe better in smtpd_sender_restrictions
 249       #"reject_rbl_client bl.spamcop.net"
 250       #"reject_rbl_client list.dsbl.org"
 251       #"reject_rbl_client zen.spamhaus.org"
 252       #"reject_rbl_client dnsbl.sorbs.net"
 253     ];
 254     smtpd_relay_restrictions = [
 255       "permit_mynetworks"
 256       "permit_sasl_authenticated"
 257         # NOTE: permit auth through dovecot's SASL
 258       "reject_unauth_destination"
 259     ];
 260     #smtpd_restriction_classes = "";
 261     broken_sasl_auth_clients = false;
 262     #smtpd_sasl_auth_enable = true;
 263     #smtpd_sasl_path = "private/auth";
 264     #smtpd_sasl_security_options = "noanonymous";
 265     #smtpd_sasl_type = "dovecot";
 266     smtpd_sender_restrictions = [
 267       "permit_mynetworks"
 268       #"permit_tls_clientcerts"
 269       "permit_sasl_authenticated"
 270         # NOTE: permit auth through dovecot's SASL
 271       #"check_sender_access hash:/var/lib/postfix/conf/sender_access"
 272       "reject_unauth_pipelining"
 273       "reject_non_fqdn_sender"
 274       #"reject_sender_login_mismatch"
 275       #"reject_unknown_sender_domain"
 276       "permit"
 277     ];
 278     smtpd_starttls_timeout = "300s";
 279     #smtpd_tls_always_issue_session_ids = true;
 280     # No SASL AUTH without TLS
 281     smtpd_tls_auth_only = true;
 282     #smtpd_tls_CApath = "/etc/postfix/x509/ca/";
 283     smtpd_tls_ask_ccert = false;
 284     #smtpd_tls_ccert_verifydepth = "5";
 285     smtpd_tls_ciphers = "high";
 286     smtpd_tls_eecdh_grade = "ultra";
 287     # Disable weak ciphers as reported by https://ssl-tools.net
 288     # https://serverfault.com/questions/744168/how-to-disable-rc4-on-postfix
 289     smtpd_tls_exclude_ciphers = [ "RC4" "aNULL" ];
 290     smtpd_tls_fingerprint_digest = "sha512";
 291     # Log only a summary message on TLS handshake completion
 292     smtpd_tls_loglevel = "1";
 293     smtpd_tls_mandatory_ciphers = "high";
 294     smtpd_tls_mandatory_protocols = "TLSv1"; # FIXME: TLSv1.3
 295     # Only allow TLSv*
 296     smtpd_tls_protocols = [ "!SSLv2" "!SSLv3" ];
 297     #smtpd_tls_received_header = false;
 298     smtpd_tls_req_ccert = false;
 299     # Postfix 2.3 and later
 300     # encrypt
 301     #  Mandatory TLS encryption: announce STARTTLS support to SMTP clients, and require that clients use TLS
 302     #  encryption. According to [1720]RFC 2487 this MUST NOT be applied in case of a publicly-referenced
 303     #  SMTP server. Instead, this option should be used only on dedicated servers.
 304     smtpd_tls_security_level = "may";
 305     smtpd_tls_session_cache_database = "btree:$data_directory/smtpd_tls_session_cache";
 306     #smtpd_tls_session_cache_timeout = "3600s";
 307     # Stops mail from poorly written software
 308     strict_rfc821_envelopes = true;
 309     #sympa_destination_recipient_limit = "1";
 310     #sympabounce_destination_recipient_limit = "1";
 311     # postconf(5) discourages to change this
 312     #tls_high_cipherlist = "AES256-SHA";
 313     #tls_random_bytes = "32";
 314     # Must not be in a chroot
 315     #tls_random_exchange_name = "$data_directory/prng_exch";
 316     #tls_random_prng_update_period = "3600s";
 317     #tls_random_reseed_period = "3600s";
 318     # Use a non blocking source of randomness
 319     tls_random_source = "dev:/dev/urandom";
 320     transport_maps = [
 321       #"ldap:transport"
 322       #"hash:/etc/postfix/transport-dovecot"
 323       #"hash:/etc/postfix/$mydomain/transport"
 324       #"hash:/etc/dovecot/transport"
 325       #"regexp:/etc/sympa/transport"
 326     ];
 327     # Rejects immediately what $fallback_transport rejects
 328     unverified_recipient_reject_code = "550";
 329     # Do not specify virtual alias domain names in mydestination
 330     # or relay_domains configuration parameters
 331     #
 332     # With  a  virtual  alias  domain,  the  Postfix SMTP server
 333     # accepts  mail  for  known-user@virtual-alias.domain,   and
 334     # rejects   mail  for  unknown-user@virtual-alias.domain  as
 335     # undeliverable.
 336     virtual_alias_domains = [];
 337     virtual_alias_maps = [
 338       #"hash:/etc/postfix/virtual_alias_maps"
 339       #"hash:/etc/postfix/virtual_domain_alias_maps"
 340       "ldap:/etc/postfix/ldap-forward.cf"
 341       "ldap:/etc/postfix/ldap-virtual_alias_maps.cf"
 342       #"hash:/etc/postfix/virtual_alias-dovecot"
 343       #"hash:/var/lib/postfix/conf/valias"
 344       #"regexp:/etc/sympa/virtual_alias"
 345     ];
 346     #virtual_uid_maps = "static:5000";
 347     #virtual_gid_maps = "static:5000";
 348     #virtual_mailbox_base = dovecot2.mailDir;
 349     virtual_mailbox_domains = [ networking.domain ] ++ networking.domainAliases;
 350     #virtual_mailbox_maps = "hash:/etc/postfix/virtual_mailbox_maps";
 351     virtual_transport = "lmtp:unix:private/dovecot-lmtp";
 352   };
 353   #submissionOptions = {
 354   #  smtpd_tls_security_level     = "encrypt";
 355   #  smtpd_sasl_auth_enable       = "yes";
 356   #  smtpd_sasl_type              = "dovecot";
 357   #  smtpd_sasl_path              = "private/auth";
 358   #  smtpd_sasl_security_options  = "noanonymous";
 359   #  smtpd_sasl_local_domain      = "$myhostname";
 360   #  smtpd_client_restrictions    = "permit_sasl_authenticated,reject";
 361   #  smtpd_sender_login_maps      = "hash:/etc/postfix/vaccounts";
 362   #  smtpd_sender_restrictions    = "reject_sender_login_mismatch";
 363   #  smtpd_recipient_restrictions = "reject_non_fqdn_recipient,reject_unknown_recipient_domain,permit_sasl_authenticated,reject";
 364   #  cleanup_service_name         = "submission-header-cleanup";
 365   #};
 366   extraMasterConf = ''
 367     #spfcheck    unix  -        n       n       -        0        spawn
 368     #  user=policyd-spf argv=/usr/sbin/postfix-policyd-spf-perl
 369     465         inet  n        -       -       -        -        smtpd
 370       -o milter_macro_daemon_name=ORIGINATING
 371       -o smtpd_client_restrictions=permit_sasl_authenticated,reject
 372       -o smtpd_recipient_restrictions=reject_non_fqdn_recipient,reject_unknown_recipient_domain,permit_sasl_authenticated,reject
 373       -o smtpd_sasl_auth_enable=yes
 374       -o smtpd_sasl_local_domain=$myhostname
 375       -o smtpd_sasl_path=private/auth
 376       -o smtpd_sasl_security_options=noanonymous
 377       -o smtpd_sasl_type=dovecot
 378       -o smtpd_tls_ask_ccert=no
 379       -o smtpd_tls_auth_only=yes
 380       -o smtpd_tls_ccert_verifydepth=0
 381       -o smtpd_tls_loglevel=1
 382       -o smtpd_tls_req_ccert=no
 383       -o smtpd_tls_security_level=encrypt
 384       -o smtpd_tls_wrappermode=yes
 385     # -o smtpd_sender_restrictions=reject_sender_login_mismatch
 386     # -o smtpd_sender_login_maps=hash:/etc/postfix/vaccounts
 387     # -o cleanup_service_name=submission-header-cleanup
 388     submission-header-cleanup unix n - n    -       0       cleanup
 389       -o header_checks=pcre:${submissionHeaderCleanupRules}
 390     #spfcheck  unix  -       n       n       -       0       spawn
 391     #  user=policyd-spf argv=/usr/bin/postfix-policyd-spf-perl
 392     #uucp      unix  -       n       n       -       -       pipe
 393     #  flags=Fqhu user=uucp argv=uux -r -n -z -a$sender - $nexthop!rmail ($recipient)
 394     #smtp      inet  n       -       -       -       -       smtpd
 395     #  -o cleanup_service_name=pre-cleanup
 396     #  -o content_filter=amavis:[127.0.0.1]:10024
 397     #  -o smtpd_sender_restrictions=reject_unauth_pipelining,reject_non_fqdn_sender,permit
 398     #  -o receive_override_options=no_address_mappings
 399     #amavis    unix  -       -       n        -      2       lmtp
 400     #  -o lmtp_data_done_timeout=1200
 401     #  -o lmtp_send_xforward_command=yes
 402     #  -o lmtp_tls_note_starttls_offer=no
 403     #127.0.0.1:10025 inet n  -       n       -       -       smtpd
 404     #  -o content_filter=
 405     #  -o local_header_rewrite_clients=
 406     #  -o local_recipient_maps=
 407     #  -o mynetworks=127.0.0.0/8
 408     #  -o receive_override_options=no_header_body_checks,no_milters,no_unknown_recipient_checks
 409     #  -o relay_recipient_maps=
 410     #  -o smtpd_client_connection_count_limit=0
 411     #  -o smtpd_client_connection_rate_limit=0
 412     #  -o smtpd_client_restrictions=permit_mynetworks,reject
 413     #  -o smtpd_data_restrictions=reject_unauth_pipelining
 414     #  -o smtpd_delay_reject=no
 415     #  -o smtpd_end_of_data_restrictions=
 416     #  -o smtpd_error_sleep_time=0
 417     #  -o smtpd_hard_error_limit=1000
 418     #  -o smtpd_helo_restrictions=
 419     #  -o smtpd_milters=
 420     #  -o smtpd_recipient_restrictions=permit_mynetworks,reject
 421     #  -o smtpd_restriction_classes=
 422     #  -o smtpd_sender_restrictions=
 423     #  -o smtpd_soft_error_limit=1001
 424     #  -o strict_rfc821_envelopes=yes
 425     #submission inet n       -       -       -       -       smtpd
 426     #  -o cleanup_service_name=pre-cleanup
 427     #  -o content_filter=amavis:[127.0.0.1]:10024
 428     #  -o milter_macro_daemon_name=ORIGINATING
 429     #  -o receive_override_options=no_address_mappings
 430     #  -o smtpd_sender_restrictions=permit_tls_clientcerts,reject
 431     #  -o smtpd_tls_ask_ccert=yes
 432     #  -o smtpd_tls_auth_only=yes
 433     #  -o smtpd_tls_ccert_verifydepth=2
 434     #  -o smtpd_tls_loglevel=1
 435     #  -o smtpd_tls_req_ccert=yes
 436     #  -o smtpd_tls_security_level=encrypt
 437     #smtps     inet  n       -       -       -       -       smtpd
 438     #  -o milter_macro_daemon_name=ORIGINATING
 439     #  -o smtpd_client_restrictions=permit_sasl_authenticated,reject
 440     #  -o smtpd_sasl_auth_enable=yes
 441     #  -o smtpd_tls_ask_ccert=yes
 442     #  -o smtpd_tls_auth_only=yes
 443     #  -o smtpd_tls_ccert_verifydepth=0
 444     #  -o smtpd_tls_loglevel=1
 445     #  -o smtpd_tls_req_ccert=no
 446     #  -o smtpd_tls_security_level=encrypt
 447     #  -o smtpd_tls_wrappermode=yes
 448     #pickup    fifo  n       -       -       60      1       pickup
 449     #  -o cleanup_service_name=pre-cleanup
 450     #  -o content_filter=amavis:[127.0.0.1]:10024
 451     #pre-cleanup unix n      -       -       -       0       cleanup
 452     #  -o virtual_alias_maps=
 453     #cleanup   unix  n       -       -       -       0       cleanup
 454     #  -o mime_header_checks=
 455     #  -o nested_header_checks=
 456     #  -o body_checks=
 457     #  -o header_checks=
 458     #-- SYMPA begin
 459     #sympa unix - n n - - pipe
 460     #  flags=R user=sympa argv=/usr/lib/sympa/bin/queue ''${recipient}
 461     #sympabounce unix - n n - - pipe
 462     #  flags=R user=sympa argv=/usr/lib/sympa/bin/bouncequeue ''${recipient}
 463     #-- SYMPA end
 464   '';
 465    #noclue    unix  -       n       n       -       -       pipe
 466    #  flags=q user=noclue argv=/usr/local/bin/noclue-delivery ${recipient} ${sender}
 467 };
 468 }