nixos-mailserver/mail-server/dovecot.nix
Bjørn Forsman a3b03d1b5a Use umask for race-free permission setting
Without using umask there's a small time window where paths are world
readable. That is a bad idea to do for secret files (e.g. the dovecot
code path).
2023-07-17 18:22:16 +02:00

396 lines
13 KiB
Nix

# nixos-mailserver: a simple mail server
# Copyright (C) 2016-2018 Robin Raymond
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>
{ config, pkgs, lib, ... }:
with (import ./common.nix { inherit config pkgs lib; });
let
cfg = config.mailserver;
passwdDir = "/run/dovecot2";
passwdFile = "${passwdDir}/passwd";
userdbFile = "${passwdDir}/userdb";
# This file contains the ldap bind password
ldapConfFile = "${passwdDir}/dovecot-ldap.conf.ext";
bool2int = x: if x then "1" else "0";
maildirLayoutAppendix = lib.optionalString cfg.useFsLayout ":LAYOUT=fs";
# maildir in format "/${domain}/${user}"
dovecotMaildir =
"maildir:${cfg.mailDirectory}/%d/%n${maildirLayoutAppendix}"
+ (lib.optionalString (cfg.indexDir != null)
":INDEX=${cfg.indexDir}/%d/%n"
);
postfixCfg = config.services.postfix;
dovecot2Cfg = config.services.dovecot2;
stateDir = "/var/lib/dovecot";
pipeBin = pkgs.stdenv.mkDerivation {
name = "pipe_bin";
src = ./dovecot/pipe_bin;
buildInputs = with pkgs; [ makeWrapper coreutils bash rspamd ];
buildCommand = ''
mkdir -p $out/pipe/bin
cp $src/* $out/pipe/bin/
chmod a+x $out/pipe/bin/*
patchShebangs $out/pipe/bin
for file in $out/pipe/bin/*; do
wrapProgram $file \
--set PATH "${pkgs.coreutils}/bin:${pkgs.rspamd}/bin"
done
'';
};
ldapConfig = pkgs.writeTextFile {
name = "dovecot-ldap.conf.ext.template";
text = ''
ldap_version = 3
uris = ${lib.concatStringsSep " " cfg.ldap.uris}
${lib.optionalString cfg.ldap.startTls ''
tls = yes
''}
tls_require_cert = hard
tls_ca_cert_file = ${cfg.ldap.tlsCAFile}
dn = ${cfg.ldap.bind.dn}
sasl_bind = no
auth_bind = yes
base = ${cfg.ldap.searchBase}
scope = ${mkLdapSearchScope cfg.ldap.searchScope}
${lib.optionalString (cfg.ldap.dovecot.userAttrs != "") ''
user_attrs = ${cfg.ldap.dovecot.userAttrs}
''}
user_filter = ${cfg.ldap.dovecot.userFilter}
${lib.optionalString (cfg.ldap.dovecot.passAttrs != "") ''
pass_attrs = ${cfg.ldap.dovecot.passAttrs}
''}
pass_filter = ${cfg.ldap.dovecot.passFilter}
'';
};
setPwdInLdapConfFile = appendLdapBindPwd {
name = "ldap-conf-file";
file = ldapConfig;
prefix = "dnpass = ";
passwordFile = cfg.ldap.bind.passwordFile;
destination = ldapConfFile;
};
genPasswdScript = pkgs.writeScript "generate-password-file" ''
#!${pkgs.stdenv.shell}
set -euo pipefail
if (! test -d "${passwdDir}"); then
mkdir "${passwdDir}"
chmod 755 "${passwdDir}"
fi
# Prevent world-readable password files, even temporarily.
umask 077
for f in ${builtins.toString (lib.mapAttrsToList (name: value: passwordFiles."${name}") cfg.loginAccounts)}; do
if [ ! -f "$f" ]; then
echo "Expected password hash file $f does not exist!"
exit 1
fi
done
cat <<EOF > ${passwdFile}
${lib.concatStringsSep "\n" (lib.mapAttrsToList (name: value:
"${name}:${"$(head -n 1 ${passwordFiles."${name}"})"}::::::"
) cfg.loginAccounts)}
EOF
cat <<EOF > ${userdbFile}
${lib.concatStringsSep "\n" (lib.mapAttrsToList (name: value:
"${name}:::::::"
+ (if lib.isString value.quota
then "userdb_quota_rule=*:storage=${value.quota}"
else "")
) cfg.loginAccounts)}
EOF
'';
junkMailboxes = builtins.attrNames (lib.filterAttrs (n: v: v ? "specialUse" && v.specialUse == "Junk") cfg.mailboxes);
junkMailboxNumber = builtins.length junkMailboxes;
# The assertion garantees there is exactly one Junk mailbox.
junkMailboxName = if junkMailboxNumber == 1 then builtins.elemAt junkMailboxes 0 else "";
mkLdapSearchScope = scope: (
if scope == "sub" then "subtree"
else if scope == "one" then "onelevel"
else scope
);
in
{
config = with cfg; lib.mkIf enable {
assertions = [
{
assertion = junkMailboxNumber == 1;
message = "nixos-mailserver requires exactly one dovecot mailbox with the 'special use' flag set to 'Junk' (${builtins.toString junkMailboxNumber} have been found)";
}
];
# for sieve-test. Shelling it in on demand usually doesnt' work, as it reads
# the global config and tries to open shared libraries configured in there,
# which are usually not compatible.
environment.systemPackages = [
pkgs.dovecot_pigeonhole
];
services.dovecot2 = {
enable = true;
enableImap = enableImap || enableImapSsl;
enablePop3 = enablePop3 || enablePop3Ssl;
enablePAM = false;
enableQuota = true;
mailGroup = vmailGroupName;
mailUser = vmailUserName;
mailLocation = dovecotMaildir;
sslServerCert = certificatePath;
sslServerKey = keyPath;
enableLmtp = true;
modules = [ pkgs.dovecot_pigeonhole ] ++ (lib.optional cfg.fullTextSearch.enable pkgs.dovecot_fts_xapian );
mailPlugins.globally.enable = lib.optionals cfg.fullTextSearch.enable [ "fts" "fts_xapian" ];
protocols = lib.optional cfg.enableManageSieve "sieve";
sieveScripts = {
after = builtins.toFile "spam.sieve" ''
require "fileinto";
if header :is "X-Spam" "Yes" {
fileinto "${junkMailboxName}";
stop;
}
'';
};
mailboxes = cfg.mailboxes;
extraConfig = ''
#Extra Config
${lib.optionalString debug ''
mail_debug = yes
auth_debug = yes
verbose_ssl = yes
''}
${lib.optionalString (cfg.enableImap || cfg.enableImapSsl) ''
service imap-login {
inet_listener imap {
${if cfg.enableImap then ''
port = 143
'' else ''
# see https://dovecot.org/pipermail/dovecot/2010-March/047479.html
port = 0
''}
}
inet_listener imaps {
${if cfg.enableImapSsl then ''
port = 993
ssl = yes
'' else ''
# see https://dovecot.org/pipermail/dovecot/2010-March/047479.html
port = 0
''}
}
}
''}
${lib.optionalString (cfg.enablePop3 || cfg.enablePop3Ssl) ''
service pop3-login {
inet_listener pop3 {
${if cfg.enablePop3 then ''
port = 110
'' else ''
# see https://dovecot.org/pipermail/dovecot/2010-March/047479.html
port = 0
''}
}
inet_listener pop3s {
${if cfg.enablePop3Ssl then ''
port = 995
ssl = yes
'' else ''
# see https://dovecot.org/pipermail/dovecot/2010-March/047479.html
port = 0
''}
}
}
''}
protocol imap {
mail_max_userip_connections = ${toString cfg.maxConnectionsPerUser}
mail_plugins = $mail_plugins imap_sieve
}
protocol pop3 {
mail_max_userip_connections = ${toString cfg.maxConnectionsPerUser}
}
mail_access_groups = ${vmailGroupName}
ssl = required
ssl_min_protocol = TLSv1.2
ssl_prefer_server_ciphers = yes
service lmtp {
unix_listener dovecot-lmtp {
group = ${postfixCfg.group}
mode = 0600
user = ${postfixCfg.user}
}
}
recipient_delimiter = ${cfg.recipientDelimiter}
lmtp_save_to_detail_mailbox = ${cfg.lmtpSaveToDetailMailbox}
protocol lmtp {
mail_plugins = $mail_plugins sieve
}
passdb {
driver = passwd-file
args = ${passwdFile}
}
userdb {
driver = passwd-file
args = ${userdbFile}
default_fields = uid=${builtins.toString cfg.vmailUID} gid=${builtins.toString cfg.vmailUID} home=${cfg.mailDirectory}
}
${lib.optionalString cfg.ldap.enable ''
passdb {
driver = ldap
args = ${ldapConfFile}
}
userdb {
driver = ldap
args = ${ldapConfFile}
default_fields = home=/var/vmail/ldap/%u uid=${toString cfg.vmailUID} gid=${toString cfg.vmailUID}
}
''}
service auth {
unix_listener auth {
mode = 0660
user = ${postfixCfg.user}
group = ${postfixCfg.group}
}
}
auth_mechanisms = plain login
namespace inbox {
separator = ${cfg.hierarchySeparator}
inbox = yes
}
plugin {
sieve_plugins = sieve_imapsieve sieve_extprograms
sieve = file:${cfg.sieveDirectory}/%u/scripts;active=${cfg.sieveDirectory}/%u/active.sieve
sieve_default = file:${cfg.sieveDirectory}/%u/default.sieve
sieve_default_name = default
# From elsewhere to Spam folder
imapsieve_mailbox1_name = ${junkMailboxName}
imapsieve_mailbox1_causes = COPY,APPEND
imapsieve_mailbox1_before = file:${stateDir}/imap_sieve/report-spam.sieve
# From Spam folder to elsewhere
imapsieve_mailbox2_name = *
imapsieve_mailbox2_from = ${junkMailboxName}
imapsieve_mailbox2_causes = COPY
imapsieve_mailbox2_before = file:${stateDir}/imap_sieve/report-ham.sieve
sieve_pipe_bin_dir = ${pipeBin}/pipe/bin
sieve_global_extensions = +vnd.dovecot.pipe +vnd.dovecot.environment
}
${lib.optionalString cfg.fullTextSearch.enable ''
plugin {
plugin = fts fts_xapian
fts = xapian
fts_xapian = partial=${toString cfg.fullTextSearch.minSize} full=${toString cfg.fullTextSearch.maxSize} attachments=${bool2int cfg.fullTextSearch.indexAttachments} verbose=${bool2int cfg.debug}
fts_autoindex = ${if cfg.fullTextSearch.autoIndex then "yes" else "no"}
${lib.strings.concatImapStringsSep "\n" (n: x: "fts_autoindex_exclude${if n==1 then "" else toString n} = ${x}") cfg.fullTextSearch.autoIndexExclude}
fts_enforced = ${cfg.fullTextSearch.enforced}
}
${lib.optionalString (cfg.fullTextSearch.memoryLimit != null) ''
service indexer-worker {
vsz_limit = ${toString (cfg.fullTextSearch.memoryLimit*1024*1024)}
}
''}
''}
lda_mailbox_autosubscribe = yes
lda_mailbox_autocreate = yes
'';
};
systemd.services.dovecot2 = {
preStart = ''
${genPasswdScript}
rm -rf '${stateDir}/imap_sieve'
mkdir '${stateDir}/imap_sieve'
cp -p "${./dovecot/imap_sieve}"/*.sieve '${stateDir}/imap_sieve/'
for k in "${stateDir}/imap_sieve"/*.sieve ; do
${pkgs.dovecot_pigeonhole}/bin/sievec "$k"
done
chown -R '${dovecot2Cfg.mailUser}:${dovecot2Cfg.mailGroup}' '${stateDir}/imap_sieve'
'' + (lib.optionalString cfg.ldap.enable setPwdInLdapConfFile);
};
systemd.services.postfix.restartTriggers = [ genPasswdScript ] ++ (lib.optional cfg.ldap.enable [setPwdInLdapConfFile]);
systemd.services.dovecot-fts-xapian-optimize = lib.mkIf (cfg.fullTextSearch.enable && cfg.fullTextSearch.maintenance.enable) {
description = "Optimize dovecot indices for fts_xapian";
requisite = [ "dovecot2.service" ];
after = [ "dovecot2.service" ];
startAt = cfg.fullTextSearch.maintenance.onCalendar;
serviceConfig = {
Type = "oneshot";
ExecStart = "${pkgs.dovecot}/bin/doveadm fts optimize -A";
PrivateDevices = true;
PrivateNetwork = true;
ProtectKernelTunables = true;
ProtectKernelModules = true;
ProtectControlGroups = true;
ProtectHome = true;
ProtectSystem = true;
PrivateTmp = true;
};
};
systemd.timers.dovecot-fts-xapian-optimize = lib.mkIf (cfg.fullTextSearch.enable && cfg.fullTextSearch.maintenance.enable && cfg.fullTextSearch.maintenance.randomizedDelaySec != 0) {
timerConfig = {
RandomizedDelaySec = cfg.fullTextSearch.maintenance.randomizedDelaySec;
};
};
};
}