servers/mermet/postfix.nix

   1 { pkgs, lib, config, ... }:
   2 let
   3   inherit (builtins) attrNames concatStringsSep readFile toPath;
   4   inherit (lib) types;
   5   inherit (pkgs.lib) loadFile unlines unwords unlinesAttrs;
   6   inherit (config) networking users;
   7   inherit (config.services) postfix dovecot2 openldap;
   8   domains = [
   9     "sourcephile.fr"
  10     "autogeree.net"
  11   ];
  12 in
  13 {
  14 imports = map (domain: (./postfix + "/${domain}.nix")) domains;
  15 options = {
  16   services.postfix = {
  17     tls_server_sni_maps = lib.mkOption {
  18       type = types.attrsOf (types.listOf types.path);
  19       default = {};
  20       apply = m: pkgs.writeText "sni" (lib.concatStringsSep "\n" (lib.mapAttrsToList (domain: x509: ''
  21         ${domain} ${unwords x509}
  22       '') m));
  23     };
  24   };
  25 };
  26 config = {
  27 users.groups.acme.members = [ postfix.user ];
  28 systemd.services.postfix = {
  29   wants = ["openldap.service"];
  30   after = ["openldap.service"];
  31   preStart = ''
  32     install -m 400 -o root -g root ${postfix.tls_server_sni_maps} /run/keys/postfix-sni
  33     ${pkgs.postfix}/bin/postmap -F hash:/run/keys/postfix-sni
  34   '';
  35 };
  36 networking.nftables.ruleset = ''
  37   add rule inet filter net2fw tcp dport 25 counter accept comment "SMTP"
  38   add rule inet filter net2fw tcp dport 465 counter accept comment "submissions"
  39   add rule inet filter fw2net tcp dport 25 counter accept comment "SMTP"
  40 '';
  41 services.postfix = {
  42   enable = true;
  43   networksStyle = "host";
  44   hostname ="${networking.hostName}.${networking.domain}";
  45   domain = networking.domain;
  46   origin = "$myhostname";
  47   destination = [
  48     "localhost"
  49     "localhost.localdomain"
  50     "$myhostname"
  51   ];
  52   postmasterAlias = "root";
  53   rootAlias = "root@${networking.domain}";
  54   sslKey = "/var/lib/acme/${networking.domain}/key.pem";
  55   sslCert = "/var/lib/acme/${networking.domain}/fullchain.pem";
  56   networks = [
  57     "127.0.0.0/8"
  58     "[::1]/128"
  59   ];
  60   setSendmail = true;
  61   # Parse the extension in email address, eg. contact+extension@
  62   recipientDelimiter = "+";
  63   config = {
  64     debug_peer_level = "4";
  65     debug_peer_list = [
  66       #"chomsky.autogeree.net"
  67       #"localhost"
  68       #"mail.sourcephile.fr"
  69     ];
  70
  71     #
  72     # Sending to the world
  73     #
  74     # Appending .domain is the MUA's job
  75     append_dot_mydomain = false;
  76     smtp_body_checks = "";
  77     #smtp_cname_overrides_servername = false;
  78     smtp_connect_timeout = "60s";
  79     #smtp_header_checks = "regexp:/var/lib/postfix/smtp_header_checks";
  80     smtp_mime_header_checks = "";
  81     smtp_nested_header_checks = "";
  82     smtp_tls_exclude_ciphers = [ "ADH" "MD5" "CAMELLIA" "SEED" "3DES" "DES" "RC4" "eNULL" "aNULL" ];
  83     #smtp_tls_fingerprint_digest = "sha1";
  84     smtp_tls_loglevel = "1";
  85     #smtp_tls_note_starttls_offer = true;
  86     #smtp_tls_policy_maps = "hash:/var/lib/postfix/conf/tls_policy";
  87     # Only allow TLSv* protocols
  88     smtp_tls_protocols = [ "!SSLv2" "!SSLv3" ];
  89     #smtp_tls_scert_verifydepth = "5";
  90     #smtp_tls_secure_cert_match = [ "nexthop" "dot-nexthop" ];
  91     smtp_tls_security_level = "may";
  92     smtp_tls_session_cache_database = "btree:$data_directory/smtp_tls_session_cache";
  93     #smtp_tls_session_cache_timeout = "3600s";
  94     #smtp_tls_verify_cert_match = "hostname";
  95
  96     #
  97     # Receiving from the world
  98     #
  99     message_size_limit = "20480000";
 100     maximal_queue_lifetime = "5d";
 101     default_extra_recipient_limit = "5000";
 102     line_length_limit = "2048";
 103     duplicate_filter_limit = "5000";
 104     # Stops mail from poorly written software
 105     strict_rfc821_envelopes = true;
 106     mime_header_checks = [];
 107     milter_header_checks = [];
 108     nested_header_checks = [];
 109     body_checks = [];
 110     content_filter = "";
 111     permit_mx_backup_networks = [];
 112     propagate_unmatched_extensions = [ "canonical" "virtual" "alias" ];
 113     #masquerade_classes = [ "envelope_sender" "header_sender" "header_recipient" ];
 114     #masquerade_domains = "";
 115     #masquerade_exceptions = "root";
 116     queue_minfree = "0";
 117     # Stops some techniques used to harvest email addresses
 118     disable_vrfy_command = true;
 119     enable_long_queue_ids = false;
 120     # Useful to test restrictions
 121     smtpd_authorized_xclient_hosts = "127.0.0.1";
 122     smtpd_banner = "$myhostname ESMTP $mail_name (NixOS)";
 123     smtpd_client_connection_count_limit = "50";
 124     smtpd_client_connection_rate_limit = "0";
 125     smtpd_client_event_limit_exceptions = "$mynetworks";
 126     smtpd_client_message_rate_limit = "0";
 127     smtpd_client_new_tls_session_rate_limit = "0";
 128     smtpd_client_port_logging = false;
 129     smtpd_client_recipient_rate_limit = "0";
 130     # Ban 5 sec on error
 131     smtpd_error_sleep_time = "5";
 132     # Needed to enforce reject_unknown_helo_hostname
 133     smtpd_helo_required = true;
 134     smtpd_helo_restrictions = [
 135       "reject_invalid_helo_hostname"
 136       "reject_non_fqdn_helo_hostname"
 137       # Don't talk to mail systems that don't know their own hostname.
 138       "reject_unknown_helo_hostname"
 139       "permit"
 140     ];
 141     smtpd_client_restrictions = [
 142     ];
 143     # Set in postfix/*.nix and used in submissions/smptd
 144     # with reject_sender_login_mismatch
 145     smtpd_sender_login_maps = [];
 146     smtpd_sender_restrictions = [
 147       "reject_non_fqdn_sender"
 148       "permit"
 149     ];
 150     smtpd_reject_unlisted_recipient = true;
 151     # Check the RCPT TO, before smtpd_recipient_restrictions
 152     # Restrictions based on what is allowed or not,
 153     # these are applied before smtpd_recipient_restrictions
 154     smtpd_relay_restrictions = [
 155       "permit_mynetworks"
 156       # Check the recipient's address in virtual_mailbox_domains and virtual_mailbox_maps
 157       "permit_auth_destination"
 158       # The world is only authorized to use our relay for the above destinations.
 159       "reject"
 160     ];
 161     # Restrictions based on what is working or not
 162     smtpd_recipient_restrictions = [
 163       # Reject if the domain is not fully qualified
 164       "reject_non_fqdn_recipient"
 165       # Reject if the domain is not working, even before bothering to check the address
 166       "reject_unknown_recipient_domain"
 167       # Reject if the address is not working
 168       # WARNING: this does not work if the recipient is greylisting.
 169       # WARNING: verify(8) has a cache, dumpable if verify(8) is stopped, with:
 170       # postmap -s btree:/var/lib/postfix/data/verify_cache
 171       #"reject_unverified_recipient"
 172       "permit"
 173     ];
 174     # Trust the verify database
 175     #unverified_recipient_reject_code = "550";
 176     smtpd_data_restrictions = [
 177       # Force the smtpd's client to wait OK before sending
 178       "reject_unauth_pipelining"
 179       "permit"
 180     ];
 181     smtpd_end_of_data_restrictions = [
 182       # Enforce mail volume quota via policy service callouts.
 183       #check_policy_service unix:private/policy
 184     ];
 185     #smtpd_milters = "";
 186     smtpd_peername_lookup = true;
 187     smtpd_recipient_limit = "5000";
 188     smtpd_recipient_overshoot_limit = "5000";
 189     #smtpd_restriction_classes = "";
 190     #smtpd_sasl_auth_enable = true;
 191     #smtpd_sasl_path = "private/auth";
 192     #smtpd_sasl_security_options = "noanonymous";
 193     #smtpd_sasl_type = "dovecot";
 194     smtpd_starttls_timeout = "300s";
 195     #smtpd_tls_always_issue_session_ids = true;
 196     #smtpd_tls_CApath = "/etc/postfix/x509/ca/";
 197     smtpd_tls_ask_ccert = false;
 198     #smtpd_tls_ccert_verifydepth = "5";
 199     smtpd_tls_ciphers = "high";
 200     smtpd_tls_eecdh_grade = "auto";
 201     # Disable weak ciphers as reported by https://ssl-tools.net
 202     # https://serverfault.com/questions/744168/how-to-disable-rc4-on-postfix
 203     smtpd_tls_exclude_ciphers = [ "ADH" "MD5" "CAMELLIA" "SEED" "3DES" "DES" "RC4" "eNULL" "aNULL" ];
 204     smtpd_tls_fingerprint_digest = "sha512";
 205     # Log only a summary message on TLS handshake completion
 206     smtpd_tls_loglevel = "1";
 207     smtpd_tls_mandatory_ciphers = "high";
 208     smtpd_tls_mandatory_protocols = [ "!SSLv2" "!SSLv3" ];
 209     # Only allow TLSv*
 210     smtpd_tls_protocols = [ "!SSLv2" "!SSLv3" ];
 211     #smtpd_tls_received_header = false;
 212     smtpd_tls_req_ccert = false;
 213     # Postfix 2.3 and later
 214     # encrypt
 215     #  Mandatory TLS encryption: announce STARTTLS support to SMTP clients, and require that clients use TLS
 216     #  encryption. According to [1720]RFC 2487 this MUST NOT be applied in case of a publicly-referenced
 217     #  SMTP server. Instead, this option should be used only on dedicated servers.
 218     smtpd_tls_security_level = "may";
 219     smtpd_tls_session_cache_database = "btree:$data_directory/smtpd_tls_session_cache";
 220     #smtpd_tls_session_cache_timeout = "3600s";
 221     #smtpd_tls_chain_files =
 222
 223     relayhost = [];
 224     #relay_clientcerts = hash:/var/lib/postfix/conf/relay_clientcerts
 225     # This is where to put backup MX domains
 226     relay_domains = [];
 227     relay_recipient_maps = [];
 228
 229     # Use a non blocking source of randomness
 230     tls_random_source = "dev:/dev/urandom";
 231     # Map each domain to a specific X.509 certificate
 232     tls_server_sni_maps = "hash:/run/keys/postfix-sni";
 233
 234     # Only explicitely aliased accounts have a mail, not all the passwd
 235     local_recipient_maps = "$alias_maps";
 236     # Note that the local transport rewrites the envelope recipient
 237     # according to the alias_maps, and thus the aliasing is transparent
 238     # to the nexthop (eg. dovecot)
 239     #local_transport = local:$myhostname
 240     # No console bell on new mail
 241     biff = false;
 242     forward_path = [
 243       /*
 244       "$home/.forward''${recipient_delimiter}''${extension}"
 245       */
 246       "$home/.forward"
 247     ];
 248
 249     # Filled by the postfix/*.nix
 250     virtual_mailbox_domains = [];
 251     # Completed by the postfix/*.nix
 252     virtual_mailbox_maps = [
 253       "hash:/etc/postfix/virtual"
 254     ];
 255     virtual_transport = "lmtp:unix:private/dovecot-lmtp";
 256     /*
 257     dovecot_destination_recipient_limit = "1";
 258     virtual_transport = "dovecot";
 259     */
 260
 261     # There is no fallback
 262     fallback_transport = "";
 263   };
 264   virtualMapType = "hash";
 265   masterConfig =
 266     let
 267       mkVal = value:
 268         if lib.isList value
 269         then concatStringsSep "," value
 270         else
 271           if value == true then "yes"
 272           else if value == false then "no"
 273           else toString value;
 274       mkKeyVal = opt: val: [ "-o" (opt + "=" + mkVal val) ];
 275       mkArgs = args: lib.concatLists (lib.mapAttrsToList mkKeyVal args);
 276     in {
 277     pickup = {
 278       args = mkArgs {
 279         cleanup_service_name = "submissions-header-cleanup";
 280       };
 281     };
 282     # Implicit TLS on port 465
 283     # https://tools.ietf.org/html/rfc8314#section-3.3
 284     submissions = {
 285       type = "inet";
 286       private = false;
 287       command = "smtpd";
 288       args = mkArgs {
 289         syslog_name = "postfix/submissions";
 290         # Implicit TLS, not STARTTLS
 291         smtpd_tls_wrappermode = true;
 292         smtpd_tls_mandatory_protocols = [
 293           "TLSv1.3"
 294           # K-9 Mail 5.600 still requires this..
 295           "TLSv1.2"
 296         ];
 297         milter_macro_daemon_name = "ORIGINATING";
 298         smtpd_helo_restrictions = [
 299           "permit_sasl_authenticated"
 300         ] ++ postfix.config.smtpd_helo_restrictions;
 301         smtpd_relay_restrictions = [
 302           # SASL authorizes to send to the world
 303           "permit_sasl_authenticated"
 304           "reject"
 305         ];
 306         smtpd_sasl_auth_enable = true;
 307         smtpd_sasl_type = "dovecot";
 308         smtpd_sasl_path = "private/auth";
 309         smtpd_sasl_local_domain = "";
 310         # Offer SASL authentication only after a TLS-encrypted session has been established
 311         smtpd_tls_auth_only = true;
 312         smtpd_sasl_tls_security_options = [ "noanonymous" ];
 313         # Do not put SASL logins in mail headers
 314         smtpd_sasl_authenticated_header = false;
 315         # Who cares about (old) Outlook
 316         broken_sasl_auth_clients = false;
 317         smtpd_sender_restrictions = [
 318           "reject_non_fqdn_sender"
 319           # Check that the SASL user is using only its own
 320           # mail addresses on the envelope, as indicated in smtpd_sender_login_maps
 321           "reject_sender_login_mismatch"
 322           "permit"
 323         ];
 324         # No X.509 certificates for users, for now
 325         smtpd_tls_ask_ccert = false;
 326         smtpd_tls_ccert_verifydepth = 0;
 327         smtpd_tls_loglevel = 1;
 328         smtpd_tls_req_ccert = false;
 329         cleanup_service_name = "submissions-header-cleanup";
 330       };
 331     };
 332     submissions-header-cleanup = {
 333       type = "unix";
 334       private = false;
 335       maxproc = 0;
 336       command = "cleanup";
 337       args = mkArgs {
 338         header_checks = "pcre:" + pkgs.writeText "submission_header_cleanup_rules" ''
 339           # Removes sensitive headers from mails handed in via the submission or smtps port.
 340           # See https://thomas-leister.de/mailserver-debian-stretch/
 341           # Uses "pcre" style regex.
 342
 343           /^Received:/         IGNORE
 344           /^User-Agent:/       IGNORE
 345           /^X-Enigmail:/       IGNORE
 346           /^X-Mailer:/         IGNORE
 347           /^X-Originating-IP:/ IGNORE
 348         '';
 349       };
 350     };
 351   };
 352   extraMasterConf = ''
 353     #spfcheck    unix  -        n       n       -        0        spawn
 354     #  user=policyd-spf argv=/usr/sbin/postfix-policyd-spf-perl
 355     # -o smtpd_sender_restrictions=reject_sender_login_mismatch
 356     # -o smtpd_sender_login_maps=hash:/etc/postfix/vaccounts
 357     # -o cleanup_service_name=submissions-header-cleanup
 358     #spfcheck  unix  -       n       n       -       0       spawn
 359     #  user=policyd-spf argv=/usr/bin/postfix-policyd-spf-perl
 360     #uucp      unix  -       n       n       -       -       pipe
 361     #  flags=Fqhu user=uucp argv=uux -r -n -z -a$sender - $nexthop!rmail ($recipient)
 362     #smtp      inet  n       -       -       -       -       smtpd
 363     #  -o cleanup_service_name=pre-cleanup
 364     #  -o content_filter=amavis:[127.0.0.1]:10024
 365     #  -o smtpd_sender_restrictions=reject_unauth_pipelining,reject_non_fqdn_sender,permit
 366     #  -o receive_override_options=no_address_mappings
 367     #amavis    unix  -       -       n        -      2       lmtp
 368     #  -o lmtp_data_done_timeout=1200
 369     #  -o lmtp_send_xforward_command=yes
 370     #  -o lmtp_tls_note_starttls_offer=no
 371     #127.0.0.1:10025 inet n  -       n       -       -       smtpd
 372     #  -o content_filter=
 373     #  -o local_header_rewrite_clients=
 374     #  -o local_recipient_maps=
 375     #  -o mynetworks=127.0.0.0/8
 376     #  -o receive_override_options=no_header_body_checks,no_milters,no_unknown_recipient_checks
 377     #  -o relay_recipient_maps=
 378     #  -o smtpd_client_connection_count_limit=0
 379     #  -o smtpd_client_connection_rate_limit=0
 380     #  -o smtpd_client_restrictions=permit_mynetworks,reject
 381     #  -o smtpd_data_restrictions=reject_unauth_pipelining
 382     #  -o smtpd_delay_reject=no
 383     #  -o smtpd_end_of_data_restrictions=
 384     #  -o smtpd_error_sleep_time=0
 385     #  -o smtpd_hard_error_limit=1000
 386     #  -o smtpd_helo_restrictions=
 387     #  -o smtpd_milters=
 388     #  -o smtpd_recipient_restrictions=permit_mynetworks,reject
 389     #  -o smtpd_restriction_classes=
 390     #  -o smtpd_sender_restrictions=
 391     #  -o smtpd_soft_error_limit=1001
 392     #  -o strict_rfc821_envelopes=yes
 393     #submission inet n       -       -       -       -       smtpd
 394     #  -o cleanup_service_name=pre-cleanup
 395     #  -o content_filter=amavis:[127.0.0.1]:10024
 396     #  -o milter_macro_daemon_name=ORIGINATING
 397     #  -o receive_override_options=no_address_mappings
 398     #  -o smtpd_sender_restrictions=permit_tls_clientcerts,reject
 399     #  -o smtpd_tls_ask_ccert=yes
 400     #  -o smtpd_tls_auth_only=yes
 401     #  -o smtpd_tls_ccert_verifydepth=2
 402     #  -o smtpd_tls_loglevel=1
 403     #  -o smtpd_tls_req_ccert=yes
 404     #  -o smtpd_tls_security_level=encrypt
 405     #smtps     inet  n       -       -       -       -       smtpd
 406     #  -o milter_macro_daemon_name=ORIGINATING
 407     #  -o smtpd_client_restrictions=permit_sasl_authenticated,reject
 408     #  -o smtpd_sasl_auth_enable=yes
 409     #  -o smtpd_tls_ask_ccert=yes
 410     #  -o smtpd_tls_auth_only=yes
 411     #  -o smtpd_tls_ccert_verifydepth=0
 412     #  -o smtpd_tls_loglevel=1
 413     #  -o smtpd_tls_req_ccert=no
 414     #  -o smtpd_tls_security_level=encrypt
 415     #  -o smtpd_tls_wrappermode=yes
 416     #pickup    fifo  n       -       -       60      1       pickup
 417     #  -o cleanup_service_name=pre-cleanup
 418     #  -o content_filter=amavis:[127.0.0.1]:10024
 419     #pre-cleanup unix n      -       -       -       0       cleanup
 420     #  -o virtual_alias_maps=
 421     #cleanup   unix  n       -       -       -       0       cleanup
 422     #  -o mime_header_checks=
 423     #  -o nested_header_checks=
 424     #  -o body_checks=
 425     #  -o header_checks=
 426     #-- SYMPA begin
 427     #sympa unix - n n - - pipe
 428     #  flags=R user=sympa argv=/usr/lib/sympa/bin/queue ''${recipient}
 429     #sympabounce unix - n n - - pipe
 430     #  flags=R user=sympa argv=/usr/lib/sympa/bin/bouncequeue ''${recipient}
 431     #-- SYMPA end
 432   '';
 433    #noclue    unix  -       n       n       -       -       pipe
 434    #  flags=q user=noclue argv=/usr/local/bin/noclue-delivery ${recipient} ${sender}
 435 };
 436 };
 437 }