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   "${networking.domainBase}.key.pem-key.service"
  26   #"nginx.service" # letsencrypt
  27 ];
  28 deployment.keys = {
  29   "postfix.${networking.domainBase}.key.pem" = {
  30     text        = pass "x509/${networking.domainBase}/key.pem";
  31     user        = postfix.user;
  32     group       = "root";
  33     destDir     = "/run/keys/";
  34     permissions = "0400"; # WARNING: not enforced when deployment.storeKeysOnMachine = true
  35   };
  36 };
  37 services.postfix = {
  38   enable = true;
  39   #hostname = networking.domain;
  40   #domain = "localdomain";
  41   networksStyle = "host";
  42   #mapFiles."valias" = toFile "valias" (unlines (all_valiases_postfix ++ catchAllPostfix));
  43   # See https://blog.grimneko.de/2011/12/24/a-bunch-of-tips-for-improving-your-postfix-setup/
  44   # for details on how this file looks. By using the same file as valias,
  45   # every alias is uniquely owned by its user.
  46   # The user's own address is already in all_valiases_postfix.
  47   #mapFiles."vaccounts" = toFile "vaccounts" (unlines all_valiases_postfix);
  48   mapFiles."virtual_alias_maps" = pkgs.writeText "virtual_alias_maps"
  49     (unlinesAttrs
  50      (from: to: "${from} ${unwords to}")
  51      postfix.aliases);
  52   mapFiles."ldap-virtual_alias_maps.cf" = pkgs.writeText "ldap-virtual_alias_maps.cf" ''
  53     version          = 3
  54     debuglevel       = 0
  55     server_host      = ldapi://
  56     bind             = sasl
  57     sasl_mechs       = EXTERNAL
  58     search_base      = ou=posix,${openldap.domainSuffix}
  59     scope            = sub
  60     dereference      = 0
  61     query_filter     = (&(mailAlias=%s)(mailEnabled=TRUE))
  62     result_format    = %s
  63     result_attribute = mail
  64   '';
  65   mapFiles."ldap-forward.cf" = pkgs.writeText "ldap-forward.cf" ''
  66     version          = 3
  67     debuglevel       = 0
  68     server_host      = ldapi://
  69     bind             = sasl
  70     sasl_mechs       = EXTERNAL
  71     search_base      = ou=posix,${openldap.domainSuffix}
  72     scope            = sub
  73     dereference      = 0
  74     query_filter     = (&(mail=%s)(mailEnabled=TRUE))
  75     result_format    = %s
  76     result_attribute = mailForwardingAddress
  77   '';
  78   sslCert = loadFile (../../../sec/openssl + "/${networking.domainBase}/cert.self-signed.pem");
  79   sslKey = "/run/keys/postfix.${networking.domainBase}.key.pem";
  80   #enableSubmission = true;
  81   #enableSmtp = true;
  82   destination = [
  83     "localhost"
  84     "localhost.localdomain"
  85     networking.hostName
  86     "${networking.hostName}.localdomain"
  87   ];
  88   networks = [
  89     "127.0.0.0/8"
  90     "[::1]/128"
  91   ];
  92   recipientDelimiter = "+";
  93   config = {
  94     # Appending .domain is the MUA's job
  95     append_dot_mydomain = false;
  96     # No console bell on new mail
  97     biff = false;
  98     body_checks = "";
  99     #content_filter = "amavisfeed:[127.0.0.1]:10024";
 100     #debug_peer_level = 4;
 101     #debug_peer_list = ".$myhostname";
 102     default_extra_recipient_limit = "5000";
 103     # Uncomment the next line to generate "delayed mail" warnings
 104     #delay_warning_time = "4h";
 105     # Stops some techniques used to harvest email addresses
 106     disable_vrfy_command = true;
 107     duplicate_filter_limit = "5000";
 108     enable_long_queue_ids = false;
 109     # Pass unexisting $mydestination recipients to dovecot
 110     fallback_transport = "lmtp:unix:private/dovecot-lmtp";
 111     forward_path = [
 112       ''$home/.forward''${recipient_delimiter}''${extension}''
 113       "$home/.forward"
 114     ];
 115     #header_checks = "regexp:/var/lib/postfix/conf/header_checks";
 116     #inet_interfaces = "all";
 117     line_length_limit = "2048";
 118
 119     # Let $fallback_transport check existence of recipients
 120     local_recipient_maps = "";
 121     #mail_spool_directory = "/var/spool/mail";
 122       # NOTE: nixpkgs's default
 123     #local_header_rewrite_clients = "";
 124     #home_mailbox = "Maildir/";
 125     #mailbox_command = ''
 126     #  ${pkgs.procmail}/bin/procmail -t -a "$SENDER" -a "$RECIPIENT" -a "$USER" -a "$EXTENSION" -a "$DOMAIN" -a "$ORIGINAL_RECIPIENT" "$HOME/.procmailrc"
 127     #'';
 128     mailbox_size_limit = "204800000";
 129
 130     masquerade_classes = [ "envelope_sender" "header_sender" "header_recipient" ];
 131     masquerade_domains = "";
 132     masquerade_exceptions = "root";
 133     maximal_queue_lifetime = "5d";
 134     message_size_limit = "20480000";
 135     mime_header_checks = "";
 136     milter_header_checks = "";
 137     nested_header_checks = "";
 138     #non_smtpd_milters = "";
 139     parent_domain_matches_subdomains = [
 140       #"debug_peer_list"
 141       #"fast_flush_domains"
 142       #"mynetworks"
 143       #"permit_mx_backup_networks"
 144       #"qmqpd_authorized_clients"
 145       #"smtpd_access_maps"
 146     ];
 147     permit_mx_backup_networks = "";
 148     #policy-spf_time_limit = "3600s";
 149     propagate_unmatched_extensions = [ "canonical" "virtual" "alias" ];
 150     queue_minfree = "0";
 151     #receive_override_options = "no_address_mappings";
 152       # no_unknown_recipient_checks
 153       #         Do not try to reject unknown recipients (SMTP server only).
 154       #         This is typically specified AFTER an external content filter.
 155       # no_address_mappings
 156       #         Disable canonical address mapping, virtual alias map expansion,
 157       #         address masquerading, and automatic BCC (blind carbon-copy) recipients.
 158       #         This is typically specified BEFORE an external content filter (eg. amavis).
 159       # no_header_body_checks
 160       #         Disable header/body_checks. This is typically specified AFTER
 161       #         an external content filter.
 162       # no_milters
 163       #         Disable Milter (mail filter) applications.
 164       #         This is typically specified AFTER an external content filter.
 165     # Parse the extension in email address, eg. contact+extension@
 166     relayhost = "";
 167     #relay_clientcerts = hash:/var/lib/postfix/conf/relay_clientcerts
 168     # This is where to put backup MX domains
 169     relay_domains = "$mydestination";
 170     relay_recipient_maps = "";
 171     smtp_body_checks = "";
 172     #smtp_cname_overrides_servername = false;
 173     smtp_connect_timeout = "60s";
 174     #smtp_header_checks = "regexp:/var/lib/postfix/smtp_header_checks";
 175     smtp_mime_header_checks = "";
 176     smtp_nested_header_checks = "";
 177     smtp_tls_exclude_ciphers = [ "ADH" "MD5" "CAMELLIA" "SEED" "3DES" "DES" "RC4" "eNULL" "aNULL" ];
 178     #smtp_tls_fingerprint_digest = "sha1";
 179     smtp_tls_loglevel = "1";
 180     #smtp_tls_note_starttls_offer = true;
 181     #smtp_tls_policy_maps = "hash:/var/lib/postfix/conf/tls_policy";
 182     # Only allow TLSv* protocols
 183     smtp_tls_protocols = [ "!SSLv2" "!SSLv3" ];
 184     smtp_tls_scert_verifydepth = "5";
 185     #smtp_tls_secure_cert_match = [ "nexthop" "dot-nexthop" ];
 186     smtp_tls_security_level = "may";
 187     smtp_tls_session_cache_database = "btree:$data_directory/smtp_tls_session_cache";
 188     #smtp_tls_session_cache_timeout = "3600s";
 189     #smtp_tls_verify_cert_match = "hostname";
 190     # Useful to test restrictions
 191     smtpd_authorized_xclient_hosts = "127.0.0.1";
 192     smtpd_banner = "${networking.hostName} ESMTP $mail_name (NixOS)";
 193     smtpd_client_connection_count_limit = "50";
 194     smtpd_client_connection_rate_limit = "0";
 195     smtpd_client_event_limit_exceptions = "$mynetworks";
 196     smtpd_client_message_rate_limit = "0";
 197     smtpd_client_new_tls_session_rate_limit = "0";
 198     smtpd_client_port_logging = false;
 199     smtpd_client_recipient_rate_limit = "0";
 200     smtpd_client_restrictions = [
 201       #"check_client_access hash:/var/lib/postfix/conf/client_blacklist"
 202     ];
 203     smtpd_data_restrictions = [
 204       "reject_unauth_pipelining"
 205         # Force the smtp client to wait OK before sending
 206       "permit"
 207     ];
 208     # Disable opportunistic encryption
 209     smtpd_discard_ehlo_keywords = "starttls";
 210     #smtpd_end_of_data_restrictions = "";
 211     # Ban 5 sec on error
 212     smtpd_error_sleep_time = "5";
 213     smtpd_helo_required = true;
 214     smtpd_helo_restrictions = [
 215       "reject_invalid_helo_hostname"
 216       "reject_non_fqdn_helo_hostname"
 217       #"reject_unknown_helo_hostname"
 218         # May be useful to fight spam
 219       "permit"
 220     ];
 221     #smtpd_milters = "";
 222     smtpd_peername_lookup = true;
 223     smtpd_recipient_limit = "5000";
 224     smtpd_recipient_overshoot_limit = "5000";
 225     smtpd_recipient_restrictions = [
 226       "reject_non_fqdn_recipient"
 227       #"reject_invalid_hostname"
 228       "reject_unknown_recipient_domain"
 229       #"reject_non_fqdn_sender"
 230       "reject_unauth_pipelining"
 231       #"check_policy_service inet:localhost:12340"
 232       # check quota
 233       "permit_mynetworks"
 234       #"permit_tls_clientcerts"
 235       "permit_sasl_authenticated"
 236       "reject_unverified_recipient"
 237         # $fallback_transport is responsible of checking the existence of the recipient
 238         # WARNING: verify(8) has a cache, dumpable if verify(8) is stopped, with:
 239         # postmap -s btree:/var/lib/postfix/data/verify_cache
 240       # Bypass SPF check and postgrey if the recipient is not for us or someone in backup_mx
 241       "reject_unauth_destination"
 242       # Check SPF
 243       #"check_policy_service unix:private/spfcheck"
 244       # Greylisting using postgrey
 245       #"check_policy_service unix:${postgrey.socket.path}"
 246       "permit_auth_destination"
 247       "reject"
 248       #"reject_unknown_sender_domain"
 249         # Maybe better in smtpd_sender_restrictions
 250       #"reject_rbl_client bl.spamcop.net"
 251       #"reject_rbl_client list.dsbl.org"
 252       #"reject_rbl_client zen.spamhaus.org"
 253       #"reject_rbl_client dnsbl.sorbs.net"
 254     ];
 255     smtpd_relay_restrictions = [
 256       "permit_mynetworks"
 257       "permit_sasl_authenticated"
 258         # NOTE: permit auth through dovecot's SASL
 259       "reject_unauth_destination"
 260     ];
 261     #smtpd_restriction_classes = "";
 262     broken_sasl_auth_clients = false;
 263     #smtpd_sasl_auth_enable = true;
 264     #smtpd_sasl_path = "private/auth";
 265     #smtpd_sasl_security_options = "noanonymous";
 266     #smtpd_sasl_type = "dovecot";
 267     smtpd_sender_restrictions = [
 268       "permit_mynetworks"
 269       #"permit_tls_clientcerts"
 270       "permit_sasl_authenticated"
 271         # NOTE: permit auth through dovecot's SASL
 272       #"check_sender_access hash:/var/lib/postfix/conf/sender_access"
 273       "reject_unauth_pipelining"
 274       "reject_non_fqdn_sender"
 275       #"reject_sender_login_mismatch"
 276       #"reject_unknown_sender_domain"
 277       "permit"
 278     ];
 279     smtpd_starttls_timeout = "300s";
 280     #smtpd_tls_always_issue_session_ids = true;
 281     # No SASL AUTH without TLS
 282     smtpd_tls_auth_only = true;
 283     #smtpd_tls_CApath = "/etc/postfix/x509/ca/";
 284     smtpd_tls_ask_ccert = false;
 285     #smtpd_tls_ccert_verifydepth = "5";
 286     smtpd_tls_ciphers = "high";
 287     smtpd_tls_eecdh_grade = "ultra";
 288     # Disable weak ciphers as reported by https://ssl-tools.net
 289     # https://serverfault.com/questions/744168/how-to-disable-rc4-on-postfix
 290     smtpd_tls_exclude_ciphers = [ "RC4" "aNULL" ];
 291     smtpd_tls_fingerprint_digest = "sha512";
 292     # Log only a summary message on TLS handshake completion
 293     smtpd_tls_loglevel = "1";
 294     smtpd_tls_mandatory_ciphers = "high";
 295     smtpd_tls_mandatory_protocols = "TLSv1"; # FIXME: TLSv1.3
 296     # Only allow TLSv*
 297     smtpd_tls_protocols = [ "!SSLv2" "!SSLv3" ];
 298     #smtpd_tls_received_header = false;
 299     smtpd_tls_req_ccert = false;
 300     # Postfix 2.3 and later
 301     # encrypt
 302     #  Mandatory TLS encryption: announce STARTTLS support to SMTP clients, and require that clients use TLS
 303     #  encryption. According to [1720]RFC 2487 this MUST NOT be applied in case of a publicly-referenced
 304     #  SMTP server. Instead, this option should be used only on dedicated servers.
 305     smtpd_tls_security_level = "may";
 306     smtpd_tls_session_cache_database = "btree:$data_directory/smtpd_tls_session_cache";
 307     #smtpd_tls_session_cache_timeout = "3600s";
 308     # Stops mail from poorly written software
 309     strict_rfc821_envelopes = true;
 310     #sympa_destination_recipient_limit = "1";
 311     #sympabounce_destination_recipient_limit = "1";
 312     # postconf(5) discourages to change this
 313     #tls_high_cipherlist = "AES256-SHA";
 314     #tls_random_bytes = "32";
 315     # Must not be in a chroot
 316     #tls_random_exchange_name = "$data_directory/prng_exch";
 317     #tls_random_prng_update_period = "3600s";
 318     #tls_random_reseed_period = "3600s";
 319     # Use a non blocking source of randomness
 320     tls_random_source = "dev:/dev/urandom";
 321     transport_maps = [
 322       #"ldap:transport"
 323       #"hash:/etc/postfix/transport-dovecot"
 324       #"hash:/etc/postfix/$mydomain/transport"
 325       #"hash:/etc/dovecot/transport"
 326       #"regexp:/etc/sympa/transport"
 327     ];
 328     # Rejects immediately what $fallback_transport rejects
 329     unverified_recipient_reject_code = "550";
 330     # Do not specify virtual alias domain names in mydestination
 331     # or relay_domains configuration parameters
 332     #
 333     # With  a  virtual  alias  domain,  the  Postfix SMTP server
 334     # accepts  mail  for  known-user@virtual-alias.domain,   and
 335     # rejects   mail  for  unknown-user@virtual-alias.domain  as
 336     # undeliverable.
 337     virtual_alias_domains = [];
 338     virtual_alias_maps = [
 339       #"hash:/etc/postfix/virtual_alias_maps"
 340       #"hash:/etc/postfix/virtual_domain_alias_maps"
 341       "ldap:/etc/postfix/ldap-forward.cf"
 342       "ldap:/etc/postfix/ldap-virtual_alias_maps.cf"
 343       #"hash:/etc/postfix/virtual_alias-dovecot"
 344       #"hash:/var/lib/postfix/conf/valias"
 345       #"regexp:/etc/sympa/virtual_alias"
 346     ];
 347     #virtual_uid_maps = "static:5000";
 348     #virtual_gid_maps = "static:5000";
 349     #virtual_mailbox_base = dovecot2.mailDir;
 350     virtual_mailbox_domains = [ networking.domain ] ++ networking.domainAliases;
 351     #virtual_mailbox_maps = "hash:/etc/postfix/virtual_mailbox_maps";
 352     virtual_transport = "lmtp:unix:private/dovecot-lmtp";
 353   };
 354   #submissionOptions = {
 355   #  smtpd_tls_security_level     = "encrypt";
 356   #  smtpd_sasl_auth_enable       = "yes";
 357   #  smtpd_sasl_type              = "dovecot";
 358   #  smtpd_sasl_path              = "private/auth";
 359   #  smtpd_sasl_security_options  = "noanonymous";
 360   #  smtpd_sasl_local_domain      = "$myhostname";
 361   #  smtpd_client_restrictions    = "permit_sasl_authenticated,reject";
 362   #  smtpd_sender_login_maps      = "hash:/etc/postfix/vaccounts";
 363   #  smtpd_sender_restrictions    = "reject_sender_login_mismatch";
 364   #  smtpd_recipient_restrictions = "reject_non_fqdn_recipient,reject_unknown_recipient_domain,permit_sasl_authenticated,reject";
 365   #  cleanup_service_name         = "submission-header-cleanup";
 366   #};
 367   extraMasterConf = ''
 368     #spfcheck    unix  -        n       n       -        0        spawn
 369     #  user=policyd-spf argv=/usr/sbin/postfix-policyd-spf-perl
 370     465         inet  n        -       -       -        -        smtpd
 371       -o milter_macro_daemon_name=ORIGINATING
 372       -o smtpd_client_restrictions=permit_sasl_authenticated,reject
 373       -o smtpd_recipient_restrictions=reject_non_fqdn_recipient,reject_unknown_recipient_domain,permit_sasl_authenticated,reject
 374       -o smtpd_sasl_auth_enable=yes
 375       -o smtpd_sasl_local_domain=$myhostname
 376       -o smtpd_sasl_path=private/auth
 377       -o smtpd_sasl_security_options=noanonymous
 378       -o smtpd_sasl_type=dovecot
 379       -o smtpd_tls_ask_ccert=no
 380       -o smtpd_tls_auth_only=yes
 381       -o smtpd_tls_ccert_verifydepth=0
 382       -o smtpd_tls_loglevel=1
 383       -o smtpd_tls_req_ccert=no
 384       -o smtpd_tls_security_level=encrypt
 385       -o smtpd_tls_wrappermode=yes
 386     # -o smtpd_sender_restrictions=reject_sender_login_mismatch
 387     # -o smtpd_sender_login_maps=hash:/etc/postfix/vaccounts
 388     # -o cleanup_service_name=submission-header-cleanup
 389     submission-header-cleanup unix n - n    -       0       cleanup
 390       -o header_checks=pcre:${submissionHeaderCleanupRules}
 391     #spfcheck  unix  -       n       n       -       0       spawn
 392     #  user=policyd-spf argv=/usr/bin/postfix-policyd-spf-perl
 393     #uucp      unix  -       n       n       -       -       pipe
 394     #  flags=Fqhu user=uucp argv=uux -r -n -z -a$sender - $nexthop!rmail ($recipient)
 395     #smtp      inet  n       -       -       -       -       smtpd
 396     #  -o cleanup_service_name=pre-cleanup
 397     #  -o content_filter=amavis:[127.0.0.1]:10024
 398     #  -o smtpd_sender_restrictions=reject_unauth_pipelining,reject_non_fqdn_sender,permit
 399     #  -o receive_override_options=no_address_mappings
 400     #amavis    unix  -       -       n        -      2       lmtp
 401     #  -o lmtp_data_done_timeout=1200
 402     #  -o lmtp_send_xforward_command=yes
 403     #  -o lmtp_tls_note_starttls_offer=no
 404     #127.0.0.1:10025 inet n  -       n       -       -       smtpd
 405     #  -o content_filter=
 406     #  -o local_header_rewrite_clients=
 407     #  -o local_recipient_maps=
 408     #  -o mynetworks=127.0.0.0/8
 409     #  -o receive_override_options=no_header_body_checks,no_milters,no_unknown_recipient_checks
 410     #  -o relay_recipient_maps=
 411     #  -o smtpd_client_connection_count_limit=0
 412     #  -o smtpd_client_connection_rate_limit=0
 413     #  -o smtpd_client_restrictions=permit_mynetworks,reject
 414     #  -o smtpd_data_restrictions=reject_unauth_pipelining
 415     #  -o smtpd_delay_reject=no
 416     #  -o smtpd_end_of_data_restrictions=
 417     #  -o smtpd_error_sleep_time=0
 418     #  -o smtpd_hard_error_limit=1000
 419     #  -o smtpd_helo_restrictions=
 420     #  -o smtpd_milters=
 421     #  -o smtpd_recipient_restrictions=permit_mynetworks,reject
 422     #  -o smtpd_restriction_classes=
 423     #  -o smtpd_sender_restrictions=
 424     #  -o smtpd_soft_error_limit=1001
 425     #  -o strict_rfc821_envelopes=yes
 426     #submission inet n       -       -       -       -       smtpd
 427     #  -o cleanup_service_name=pre-cleanup
 428     #  -o content_filter=amavis:[127.0.0.1]:10024
 429     #  -o milter_macro_daemon_name=ORIGINATING
 430     #  -o receive_override_options=no_address_mappings
 431     #  -o smtpd_sender_restrictions=permit_tls_clientcerts,reject
 432     #  -o smtpd_tls_ask_ccert=yes
 433     #  -o smtpd_tls_auth_only=yes
 434     #  -o smtpd_tls_ccert_verifydepth=2
 435     #  -o smtpd_tls_loglevel=1
 436     #  -o smtpd_tls_req_ccert=yes
 437     #  -o smtpd_tls_security_level=encrypt
 438     #smtps     inet  n       -       -       -       -       smtpd
 439     #  -o milter_macro_daemon_name=ORIGINATING
 440     #  -o smtpd_client_restrictions=permit_sasl_authenticated,reject
 441     #  -o smtpd_sasl_auth_enable=yes
 442     #  -o smtpd_tls_ask_ccert=yes
 443     #  -o smtpd_tls_auth_only=yes
 444     #  -o smtpd_tls_ccert_verifydepth=0
 445     #  -o smtpd_tls_loglevel=1
 446     #  -o smtpd_tls_req_ccert=no
 447     #  -o smtpd_tls_security_level=encrypt
 448     #  -o smtpd_tls_wrappermode=yes
 449     #pickup    fifo  n       -       -       60      1       pickup
 450     #  -o cleanup_service_name=pre-cleanup
 451     #  -o content_filter=amavis:[127.0.0.1]:10024
 452     #pre-cleanup unix n      -       -       -       0       cleanup
 453     #  -o virtual_alias_maps=
 454     #cleanup   unix  n       -       -       -       0       cleanup
 455     #  -o mime_header_checks=
 456     #  -o nested_header_checks=
 457     #  -o body_checks=
 458     #  -o header_checks=
 459     #-- SYMPA begin
 460     #sympa unix - n n - - pipe
 461     #  flags=R user=sympa argv=/usr/lib/sympa/bin/queue ''${recipient}
 462     #sympabounce unix - n n - - pipe
 463     #  flags=R user=sympa argv=/usr/lib/sympa/bin/bouncequeue ''${recipient}
 464     #-- SYMPA end
 465   '';
 466    #noclue    unix  -       n       n       -       -       pipe
 467    #  flags=q user=noclue argv=/usr/local/bin/noclue-delivery ${recipient} ${sender}
 468 };
 469 }