diff options
Diffstat (limited to 'sys/mail')
| -rw-r--r-- | sys/mail/default.nix | 246 |
1 files changed, 246 insertions, 0 deletions
diff --git a/sys/mail/default.nix b/sys/mail/default.nix new file mode 100644 index 0000000..f87b6fe --- /dev/null +++ b/sys/mail/default.nix @@ -0,0 +1,246 @@ +{ + config, + lib, + pkgs, + ... +}: +with lib; let + cfg = config.local.mailHost; + imapHostname = config.local.domains.imap.main; + + cert = config.security.acme.certs.${imapHostname}.directory; + + inherit (config.local) users virtual; +in { + options.local.mailHost = { + enable = mkEnableOption "mailbox host service"; + + mdaListen = mkOption { + type = types.str; + }; + + saslPort = mkOption { + type = types.port; + }; + + lmtpPort = mkOption { + type = types.port; + }; + }; + + config = mkIf cfg.enable { + # 25.05: The option definition `services.dovecot2.modules' in + # `/nix/store/d3mfmsa6klf9dizidvs9qgfv4bgxqgvz-source/sys/mail' no longer + # has any effect; please remove it. Now need to use + # `environment.systemPackages` to load additional Dovecot modules + environment.systemPackages = [ + pkgs.dovecot_pigeonhole + ]; + + services = { + dovecot2 = { + enable = true; + enablePAM = false; + enableLmtp = true; + + sslServerKey = "${cert}/key.pem"; + sslServerCert = "${cert}/fullchain.pem"; + + mailUser = "vmail"; + mailGroup = "vmail"; + mailLocation = "maildir:~/mail"; + mailPlugins.perProtocol.lmtp.enable = ["sieve"]; + + # https://github.com/NixOS/nixpkgs/issues/286859 + sieve.extensions = [ + "fileinto" + "mailbox" + ]; + + extraConfig = let + inherit (config.networking) domain; + + # https://dovecot.org/list/dovecot/2019-March/115250.html + # Otra solución posible (https://serverfault.com/a/1062274/980378): + # auth_username_format = %{if;%d;eq;${domain};%Ln;%Lu} + localEntry = canonical: username: '' + ${username}:::::::user=${canonical} nopassword userdb_user=${canonical} + ''; + + localMailboxes = + pkgs.writeText "local-mailboxes" + (concatStrings + (flatten (mapAttrsToList + (canonical: user: + map (localEntry canonical) ([canonical] ++ user.hardAliases)) + users))); + + localCerts = flatten (mapAttrsToList + (canonical: user: let + certNames = { + inherit canonical; + logins = [canonical] ++ user.hardAliases; + }; + in + map (flip nameValuePair certNames) user.mail.certs) + users); + + vmailCerts = flatten (flatten (mapAttrsToList + (domain: virtual: + mapAttrsToList + (username: user: let + address = "${username}@${domain}"; + + certNames = { + canonical = address; + logins = [address]; + }; + in + map (flip nameValuePair certNames) user.mail.certs) + virtual.users) + virtual)); + + certLogins = + pkgs.writeText "cert-logins" + (concatLines (flatten (mapAttrsToList + (certPath: names: + map + (addr: "${config.local.pki.byPath.${certPath}.commonName}@nodomain,${addr}:::::::user=${names.canonical}") + names.logins) + (listToAttrs (localCerts ++ vmailCerts))))); + + vmailPath = "/var/lib/vmail/%{if;%d;ne;;%Ld;${domain}}"; + in '' + auth_mechanisms = plain login external + + ssl_ca = <${config.local.pki.ca.mail.fullchain} + ssl_require_crl = yes + ssl_verify_client_cert = yes + + # Esto descarta @domain.tld de locales explícitos, pero lo exige para los demás. + # Implicación: locales implícitos sin dominio fallan en autenticar + auth_username_format = %{if;%Ld;eq;${domain};%Ln;%{if;%d;ne;;%Lu;%Ln@nodomain}} + auth_ssl_username_from_cert = yes + + # TODO: los defaults de nixpkgs dejan los sockets bajo + # /run/dovecot2 con demasiados permisos rwx, arreglar + + service auth { + inet_listener mta-sasl { + port = ${toString cfg.saslPort} + address = ${cfg.mdaListen} + } + } + + service lmtp { + inet_listener mta-lmtp { + port = ${toString cfg.lmtpPort} + address = ${cfg.mdaListen} + } + } + + # FIXME: Esta cadena de passdbs hace que 'doveadm user lookup' + # falle para usuarios locales, pero todo lo demás sirve. Parece + # ser debido a que pam no puede enumerar. + + passdb { + driver = static + args = nopassword + + master = yes + mechanisms = external + + result_success = continue-fail + result_failure = return-fail + result_internalfail = return-fail + } + + passdb { + driver = passwd-file + args = scheme=PLAIN username_format=%{master_user},%Lu ${certLogins} + + mechanisms = external + override_fields = nopassword + + result_failure = return-fail + result_internalfail = return-fail + } + + passdb { + driver = passwd-file + args = username_format=%Ln ${vmailPath}/passwd + } + + passdb { + driver = passwd-file + args = scheme=PLAIN ${localMailboxes} + + # Esta es una forma de determinar si se encontró el usuario en + # el passwd-file por medio de nopassword sin realmente + # autenticarlo. Cuidado con result_success, porque si eso se + # configura mal se permite inicio de sesión con cualquier + # contraseña (!!!). + result_success = continue + result_failure = return-fail + result_internalfail = return-fail + + username_filter = !*@* + } + + passdb { + driver = pam + args = dovecot2 + username_filter = !*@* + #TODO: algo como 'override_fields = allow_nets=...' + } + + userdb { + driver = passwd-file + args = username_format=%Ln ${vmailPath}/passwd + override_fields = uid=vmail gid=vmail home=${vmailPath}/home/%Ln + } + + userdb { + driver = passwd-file + args = ${localMailboxes} + + result_success = continue-ok + result_internalfail = return-fail + skip = found + } + + userdb { + driver = passwd + args = blocking=no + skip = notfound + } + ''; + }; + + fail2ban.jails.dovecot.settings = { + filter = "dovecot[mode=aggressive]"; + maxretry = 3; + }; + }; + + security = { + # Necesario debido a 'enablePAM = false' + pam.services.dovecot2 = {}; + + acme.certs.${imapHostname} = { + inherit (config.services.dovecot2) group; + + reloadServices = ["dovecot2.service"]; + }; + }; + + users = { + users.${config.services.dovecot2.mailUser}.uid = 995; + groups.${config.services.dovecot2.mailGroup}.gid = 993; + }; + + networking.firewall.allowedTCPPorts = [143 993]; + + local.certs.imap.enable = true; + }; +} |