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{ config, lib, pkgs, ... }:
with lib; let
cfg = config.local.mta;
inherit (config.local) domains virtual users;
inherit (config.networking) domain;
isBackup = cfg.mode == "backup";
isPrimary = cfg.mode == "primary";
allDomains = optional (! virtualDomains ? ${domain}) domain ++ attrNames virtualDomains;
virtualDomains = filterAttrs (name: _: name != domain) virtual;
cert = config.security.acme.certs.${mtaDomain.main}.directory;
mtaDomain =
if isPrimary
then domains.smtp
else domains.smtp-backup;
mdaTransport =
if isPrimary
then "lmtp:inet:${cfg.mdaAddr}:${toString cfg.lmtpPort}"
else "error:bad transport";
in
{
options.local.mta = {
enable = mkEnableOption "mail transfer agent";
mode = mkOption {
type = types.enum [ "primary" "backup" ];
};
mdaAddr = mkOption {
type = types.str;
};
saslPort = mkOption {
type = types.port;
};
lmtpPort = mkOption {
type = types.port;
};
relayListen = mkOption {
type = types.str;
};
};
config = mkIf cfg.enable {
services = {
fail2ban.jails.postfix.settings = {
filter = "postfix[mode=aggressive]";
};
opendkim = mkIf isPrimary {
enable = true;
group = "postfix";
domains = "csl:" + concatStringsSep "," ([ domain ] ++ attrNames virtualDomains);
selector = "202408";
configFile = pkgs.writeText "opendkim.conf" ''
UMask 007
InternalHosts 0.0.0.0/0,::/0
'';
};
postfix = {
enable = true;
enableSmtp = true;
enableSubmissions = isPrimary;
inherit domain;
hostname = mtaDomain.main;
#TODO: check_recipient_access para rechazar localhost desde afuera
destination = optionals isPrimary [ "localhost" "$mydomain" ];
origin = "$mydomain";
networksStyle = "host";
relayHost = optionalString isBackup domains.smtp.main;
lookupMX = false;
relayDomains =
if isBackup
then allDomains
else null;
sslKey = "${cert}/key.pem";
sslCert = "${cert}/fullchain.pem";
# También es postmaster
rootAlias = config.local.sysadmin;
extraAliases = optionalString isPrimary
(concatLines (flatten (mapAttrsToList
(name: user: map
(alias: "${alias}: ${name}")
user.hardAliases)
users)));
localRecipients = optionals isPrimary
(map (user: "${user}@${domain}")
(attrNames (users // virtual.${domain}.users)));
virtual = optionalString isPrimary
(concatLines (flatten (mapAttrsToList
(name: virtual: mapAttrsToList
(alias: targets: "${alias}@${name} ${concatStringsSep ", " targets}")
virtual.aliases)
virtual)));
mapFiles = optionalAttrs isPrimary {
sender_ccerts =
pkgs.writeText "postfix-sender_ccerts"
(concatLines (flatten (mapAttrsToList
(username: user: map
(alias: "${alias}@${domain} CCERTS ${concatStringsSep "," (map (certPath: config.local.pki.byPath.${certPath}.fingerprint.sha256) user.mail.certs)}")
([ username ] ++ user.hardAliases))
(filterAttrs (_: user: user.mail.certs != [ ]) users))));
sender_login =
pkgs.writeText "postfix-sender_login"
(concatLines (flatten (mapAttrsToList
(username: user: map
(alias: "${alias}@${domain} ${username}")
([ username ] ++ user.hardAliases))
users)));
virtual_recipients =
pkgs.writeText "postfix-virtual_recipients"
(concatLines (flatten (mapAttrsToList
(virtualDomain: virtual: mapAttrsToList
# El lado derecho de esta tabla debe existir pero nunca se usa
(username: _: "${username}@${virtualDomain} foo")
virtual.users)
virtualDomains)));
virtual_rules =
pkgs.writeText "postfix-virtual_rules"
(concatLines (flatten (mapAttrsToList
(name: virtual: map
(rule: "/^${rule.pattern}@${name}$/ ${concatStringsSep ", " rule.targets}")
virtual.rules)
virtual)));
};
config = {
# user+extension@domain.tld
recipient_delimiter = optionalString isPrimary "+";
message_size_limit = toString (50 * 1048576);
local_transport = mdaTransport;
virtual_transport = mdaTransport;
smtpd_tls_auth_only = true;
# Nota: smtpd_tls_dh1024_param_file fue deprecado en 3.9
tls_append_default_CA = false; # Crítico
} // optionalAttrs isPrimary {
virtual_alias_maps = mkAfter [ "pcre:/etc/postfix/virtual_rules" ];
virtual_mailbox_domains = attrNames virtualDomains;
virtual_mailbox_maps = [ "hash:/etc/postfix/virtual_recipients" ];
smtpd_sasl_type = "dovecot";
smtpd_sasl_path = "inet:${cfg.mdaAddr}:${toString cfg.saslPort}";
smtpd_sasl_local_domain = "$mydomain";
smtpd_sasl_security_options = [ "noanonymous" ];
smtpd_tls_CAfile = "${config.local.pki.ca.mail.fullchain}";
smtpd_tls_ccert_verifydepth = "1";
# Inventado, no es parámetro de postfix
local_submission_client_restrictions = [
"permit_tls_all_clientcerts"
"permit_sasl_authenticated"
"reject"
];
smtpd_sender_login_maps = [ "hash:/etc/postfix/sender_login" ];
smtpd_relay_restrictions = [
"permit_mynetworks"
"permit_tls_all_clientcerts"
"permit_sasl_authenticated"
"reject_unauth_destination"
];
smtpd_sender_restrictions = [
"check_sender_access hash:/etc/postfix/sender_ccerts"
"reject_sender_login_mismatch"
];
smtpd_milters = "unix:/run/opendkim/opendkim.sock";
non_smtpd_milters = "$smtpd_milters";
milter_default_action = "accept";
} // optionalAttrs isBackup {
inet_interfaces = [ cfg.relayListen ];
smtpd_relay_restrictions = [
"reject_unauth_destination"
];
};
# Importante: existe submissionOptions por aparte, no son iguales
submissionsOptions = optionalAttrs isPrimary {
smtpd_client_restrictions = "$local_submission_client_restrictions";
smtpd_sasl_auth_enable = "yes";
smtpd_tls_ask_ccert = "yes";
smtpd_tls_security_level = "encrypt";
};
};
};
#TODO: solo para las destination addresses necesarias
networking.firewall.allowedTCPPorts = optionals isPrimary [ 25 465 ];
local = {
boot.impermanence.directories = [
{ directory = "/var/lib/postfix"; user = "root"; group = "root"; mode = "u=rwx,g=rx,o=rx"; }
] ++ optionals isPrimary [
{ directory = "/var/lib/opendkim"; user = "opendkim"; group = "postfix"; mode = "u=rwx,g=,o="; }
];
certs.smtp.enable = isPrimary;
certs.smtp-backup.enable = isBackup;
};
security.acme.certs.${mtaDomain.main}.reloadServices = [ "postfix.service" ];
};
}
|
