nixpkgs/nixos/modules/services/mail/postfix.nix
Jörg Thalheim 91ddc9d27f
postfix: add setgid wrapper for postqueue/postdrop
Both postqueue[1] and postdrop[2] implement a subset of administration
task that are supposed to be run unprivileged users
and require the setgid bit to full-fill this task.

[1] http://www.postfix.org/postqueue.1.html
[2] http://www.postfix.org/postdrop.1.html
2018-10-15 13:14:41 +01:00

880 lines
27 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.services.postfix;
user = cfg.user;
group = cfg.group;
setgidGroup = cfg.setgidGroup;
haveAliases = cfg.postmasterAlias != "" || cfg.rootAlias != ""
|| cfg.extraAliases != "";
haveTransport = cfg.transport != "";
haveVirtual = cfg.virtual != "";
clientAccess =
optional (cfg.dnsBlacklistOverrides != "")
"check_client_access hash:/etc/postfix/client_access";
dnsBl =
optionals (cfg.dnsBlacklists != [])
(map (s: "reject_rbl_client " + s) cfg.dnsBlacklists);
clientRestrictions = concatStringsSep ", " (clientAccess ++ dnsBl);
mainCf = let
escape = replaceStrings ["$"] ["$$"];
mkList = items: "\n " + concatStringsSep ",\n " items;
mkVal = value:
if isList value then mkList value
else " " + (if value == true then "yes"
else if value == false then "no"
else toString value);
mkEntry = name: value: "${escape name} =${mkVal value}";
in
concatStringsSep "\n" (mapAttrsToList mkEntry cfg.config)
+ "\n" + cfg.extraConfig;
masterCfOptions = { options, config, name, ... }: {
options = {
name = mkOption {
type = types.str;
default = name;
example = "smtp";
description = ''
The name of the service to run. Defaults to the attribute set key.
'';
};
type = mkOption {
type = types.enum [ "inet" "unix" "fifo" "pass" ];
default = "unix";
example = "inet";
description = "The type of the service";
};
private = mkOption {
type = types.bool;
example = false;
description = ''
Whether the service's sockets and storage directory is restricted to
be only available via the mail system. If <literal>null</literal> is
given it uses the postfix default <literal>true</literal>.
'';
};
privileged = mkOption {
type = types.bool;
example = true;
description = "";
};
chroot = mkOption {
type = types.bool;
example = true;
description = ''
Whether the service is chrooted to have only access to the
<option>services.postfix.queueDir</option> and the closure of
store paths specified by the <option>program</option> option.
'';
};
wakeup = mkOption {
type = types.int;
example = 60;
description = ''
Automatically wake up the service after the specified number of
seconds. If <literal>0</literal> is given, never wake the service
up.
'';
};
wakeupUnusedComponent = mkOption {
type = types.bool;
example = false;
description = ''
If set to <literal>false</literal> the component will only be woken
up if it is used. This is equivalent to postfix' notion of adding a
question mark behind the wakeup time in
<filename>master.cf</filename>
'';
};
maxproc = mkOption {
type = types.int;
example = 1;
description = ''
The maximum number of processes to spawn for this service. If the
value is <literal>0</literal> it doesn't have any limit. If
<literal>null</literal> is given it uses the postfix default of
<literal>100</literal>.
'';
};
command = mkOption {
type = types.str;
default = name;
example = "smtpd";
description = ''
A program name specifying a Postfix service/daemon process.
By default it's the attribute <option>name</option>.
'';
};
args = mkOption {
type = types.listOf types.str;
default = [];
example = [ "-o" "smtp_helo_timeout=5" ];
description = ''
Arguments to pass to the <option>command</option>. There is no shell
processing involved and shell syntax is passed verbatim to the
process.
'';
};
rawEntry = mkOption {
type = types.listOf types.str;
default = [];
internal = true;
description = ''
The raw configuration line for the <filename>master.cf</filename>.
'';
};
};
config.rawEntry = let
mkBool = bool: if bool then "y" else "n";
mkArg = arg: "${optionalString (hasPrefix "-" arg) "\n "}${arg}";
maybeOption = fun: option:
if options.${option}.isDefined then fun config.${option} else "-";
# This is special, because we have two options for this value.
wakeup = let
wakeupDefined = options.wakeup.isDefined;
wakeupUCDefined = options.wakeupUnusedComponent.isDefined;
finalValue = toString config.wakeup
+ optionalString (wakeupUCDefined && !config.wakeupUnusedComponent) "?";
in if wakeupDefined then finalValue else "-";
in [
config.name
config.type
(maybeOption mkBool "private")
(maybeOption (b: mkBool (!b)) "privileged")
(maybeOption mkBool "chroot")
wakeup
(maybeOption toString "maxproc")
(config.command + " " + concatMapStringsSep " " mkArg config.args)
];
};
masterCfContent = let
labels = [
"# service" "type" "private" "unpriv" "chroot" "wakeup" "maxproc"
"command + args"
];
labelDefaults = [
"# " "" "(yes)" "(yes)" "(no)" "(never)" "(100)" "" ""
];
masterCf = mapAttrsToList (const (getAttr "rawEntry")) cfg.masterConfig;
# A list of the maximum width of the columns across all lines and labels
maxWidths = let
foldLine = line: acc: let
columnLengths = map stringLength line;
in zipListsWith max acc columnLengths;
# We need to handle the last column specially here, because it's
# open-ended (command + args).
lines = [ labels labelDefaults ] ++ (map (l: init l ++ [""]) masterCf);
in fold foldLine (genList (const 0) (length labels)) lines;
# Pad a string with spaces from the right (opposite of fixedWidthString).
pad = width: str: let
padWidth = width - stringLength str;
padding = concatStrings (genList (const " ") padWidth);
in str + optionalString (padWidth > 0) padding;
# It's + 2 here, because that's the amount of spacing between columns.
fullWidth = fold (width: acc: acc + width + 2) 0 maxWidths;
formatLine = line: concatStringsSep " " (zipListsWith pad maxWidths line);
formattedLabels = let
sep = "# " + concatStrings (genList (const "=") (fullWidth + 5));
lines = [ sep (formatLine labels) (formatLine labelDefaults) sep ];
in concatStringsSep "\n" lines;
in formattedLabels + "\n" + concatMapStringsSep "\n" formatLine masterCf + "\n" + cfg.extraMasterConf;
headerCheckOptions = { ... }:
{
options = {
pattern = mkOption {
type = types.str;
default = "/^.*/";
example = "/^X-Mailer:/";
description = "A regexp pattern matching the header";
};
action = mkOption {
type = types.str;
default = "DUNNO";
example = "BCC mail@example.com";
description = "The action to be executed when the pattern is matched";
};
};
};
headerChecks = concatStringsSep "\n" (map (x: "${x.pattern} ${x.action}") cfg.headerChecks) + cfg.extraHeaderChecks;
aliases = let seperator = if cfg.aliasMapType == "hash" then ":" else ""; in
optionalString (cfg.postmasterAlias != "") ''
postmaster${seperator} ${cfg.postmasterAlias}
''
+ optionalString (cfg.rootAlias != "") ''
root${seperator} ${cfg.rootAlias}
''
+ cfg.extraAliases
;
aliasesFile = pkgs.writeText "postfix-aliases" aliases;
virtualFile = pkgs.writeText "postfix-virtual" cfg.virtual;
checkClientAccessFile = pkgs.writeText "postfix-check-client-access" cfg.dnsBlacklistOverrides;
mainCfFile = pkgs.writeText "postfix-main.cf" mainCf;
masterCfFile = pkgs.writeText "postfix-master.cf" masterCfContent;
transportFile = pkgs.writeText "postfix-transport" cfg.transport;
headerChecksFile = pkgs.writeText "postfix-header-checks" headerChecks;
in
{
###### interface
options = {
services.postfix = {
enable = mkOption {
type = types.bool;
default = false;
description = "Whether to run the Postfix mail server.";
};
enableSmtp = mkOption {
default = true;
description = "Whether to enable smtp in master.cf.";
};
enableSubmission = mkOption {
type = types.bool;
default = false;
description = "Whether to enable smtp submission.";
};
submissionOptions = mkOption {
type = types.attrs;
default = {
smtpd_tls_security_level = "encrypt";
smtpd_sasl_auth_enable = "yes";
smtpd_client_restrictions = "permit_sasl_authenticated,reject";
milter_macro_daemon_name = "ORIGINATING";
};
example = {
smtpd_tls_security_level = "encrypt";
smtpd_sasl_auth_enable = "yes";
smtpd_sasl_type = "dovecot";
smtpd_client_restrictions = "permit_sasl_authenticated,reject";
milter_macro_daemon_name = "ORIGINATING";
};
description = "Options for the submission config in master.cf";
};
setSendmail = mkOption {
type = types.bool;
default = true;
description = "Whether to set the system sendmail to postfix's.";
};
user = mkOption {
type = types.str;
default = "postfix";
description = "What to call the Postfix user (must be used only for postfix).";
};
group = mkOption {
type = types.str;
default = "postfix";
description = "What to call the Postfix group (must be used only for postfix).";
};
setgidGroup = mkOption {
type = types.str;
default = "postdrop";
description = "
How to call postfix setgid group (for postdrop). Should
be uniquely used group.
";
};
networks = mkOption {
type = types.nullOr (types.listOf types.str);
default = null;
example = ["192.168.0.1/24"];
description = "
Net masks for trusted - allowed to relay mail to third parties -
hosts. Leave empty to use mynetworks_style configuration or use
default (localhost-only).
";
};
networksStyle = mkOption {
type = types.str;
default = "";
description = "
Name of standard way of trusted network specification to use,
leave blank if you specify it explicitly or if you want to use
default (localhost-only).
";
};
hostname = mkOption {
type = types.str;
default = "";
description ="
Hostname to use. Leave blank to use just the hostname of machine.
It should be FQDN.
";
};
domain = mkOption {
type = types.str;
default = "";
description ="
Domain to use. Leave blank to use hostname minus first component.
";
};
origin = mkOption {
type = types.str;
default = "";
description ="
Origin to use in outgoing e-mail. Leave blank to use hostname.
";
};
destination = mkOption {
type = types.nullOr (types.listOf types.str);
default = null;
example = ["localhost"];
description = "
Full (!) list of domains we deliver locally. Leave blank for
acceptable Postfix default.
";
};
relayDomains = mkOption {
type = types.nullOr (types.listOf types.str);
default = null;
example = ["localdomain"];
description = "
List of domains we agree to relay to. Default is empty.
";
};
relayHost = mkOption {
type = types.str;
default = "";
description = "
Mail relay for outbound mail.
";
};
relayPort = mkOption {
type = types.int;
default = 25;
description = "
SMTP port for relay mail relay.
";
};
lookupMX = mkOption {
type = types.bool;
default = false;
description = "
Whether relay specified is just domain whose MX must be used.
";
};
postmasterAlias = mkOption {
type = types.str;
default = "root";
description = "
Who should receive postmaster e-mail. Multiple values can be added by
separating values with comma.
";
};
rootAlias = mkOption {
type = types.str;
default = "";
description = "
Who should receive root e-mail. Blank for no redirection.
Multiple values can be added by separating values with comma.
";
};
extraAliases = mkOption {
type = types.lines;
default = "";
description = "
Additional entries to put verbatim into aliases file, cf. man-page aliases(8).
";
};
aliasMapType = mkOption {
type = with types; enum [ "hash" "regexp" "pcre" ];
default = "hash";
example = "regexp";
description = "The format the alias map should have. Use regexp if you want to use regular expressions.";
};
config = mkOption {
type = with types; attrsOf (either bool (either str (listOf str)));
description = ''
The main.cf configuration file as key value set.
'';
example = {
mail_owner = "postfix";
smtp_use_tls = true;
};
};
extraConfig = mkOption {
type = types.lines;
default = "";
description = "
Extra lines to be added verbatim to the main.cf configuration file.
";
};
sslCert = mkOption {
type = types.str;
default = "";
description = "SSL certificate to use.";
};
sslCACert = mkOption {
type = types.str;
default = "";
description = "SSL certificate of CA.";
};
sslKey = mkOption {
type = types.str;
default = "";
description = "SSL key to use.";
};
recipientDelimiter = mkOption {
type = types.str;
default = "";
example = "+";
description = "
Delimiter for address extension: so mail to user+test can be handled by ~user/.forward+test
";
};
virtual = mkOption {
type = types.lines;
default = "";
description = "
Entries for the virtual alias map, cf. man-page virtual(8).
";
};
virtualMapType = mkOption {
type = types.enum ["hash" "regexp" "pcre"];
default = "hash";
description = ''
What type of virtual alias map file to use. Use <literal>"regexp"</literal> for regular expressions.
'';
};
transport = mkOption {
default = "";
description = "
Entries for the transport map, cf. man-page transport(8).
";
};
dnsBlacklists = mkOption {
default = [];
type = with types; listOf string;
description = "dns blacklist servers to use with smtpd_client_restrictions";
};
dnsBlacklistOverrides = mkOption {
default = "";
description = "contents of check_client_access for overriding dnsBlacklists";
};
masterConfig = mkOption {
type = types.attrsOf (types.submodule masterCfOptions);
default = {};
example =
{ submission = {
type = "inet";
args = [ "-o" "smtpd_tls_security_level=encrypt" ];
};
};
description = ''
An attribute set of service options, which correspond to the service
definitions usually done within the Postfix
<filename>master.cf</filename> file.
'';
};
extraMasterConf = mkOption {
type = types.lines;
default = "";
example = "submission inet n - n - - smtpd";
description = "Extra lines to append to the generated master.cf file.";
};
enableHeaderChecks = mkOption {
type = types.bool;
default = false;
example = true;
description = "Whether to enable postfix header checks";
};
headerChecks = mkOption {
type = types.listOf (types.submodule headerCheckOptions);
default = [];
example = [ { pattern = "/^X-Spam-Flag:/"; action = "REDIRECT spam@example.com"; } ];
description = "Postfix header checks.";
};
extraHeaderChecks = mkOption {
type = types.lines;
default = "";
example = "/^X-Spam-Flag:/ REDIRECT spam@example.com";
description = "Extra lines to /etc/postfix/header_checks file.";
};
aliasFiles = mkOption {
type = types.attrsOf types.path;
default = {};
description = "Aliases' tables to be compiled and placed into /var/lib/postfix/conf.";
};
mapFiles = mkOption {
type = types.attrsOf types.path;
default = {};
description = "Maps to be compiled and placed into /var/lib/postfix/conf.";
};
useSrs = mkOption {
type = types.bool;
default = false;
description = "Whether to enable sender rewriting scheme";
};
};
};
###### implementation
config = mkIf config.services.postfix.enable (mkMerge [
{
environment = {
etc = singleton
{ source = "/var/lib/postfix/conf";
target = "postfix";
};
# This makes it comfortable to run 'postqueue/postdrop' for example.
systemPackages = [ pkgs.postfix ];
};
services.pfix-srsd.enable = config.services.postfix.useSrs;
services.mail.sendmailSetuidWrapper = mkIf config.services.postfix.setSendmail {
program = "sendmail";
source = "${pkgs.postfix}/bin/sendmail";
group = setgidGroup;
setuid = false;
setgid = true;
};
security.wrappers.postqueue = {
program = "postqueue";
source = "${pkgs.postfix}/bin/postqueue";
group = setgidGroup;
setuid = false;
setgid = true;
};
security.wrappers.postdrop = {
program = "postdrop";
source = "${pkgs.postfix}/bin/postdrop";
group = setgidGroup;
setuid = false;
setgid = true;
};
users.users = optional (user == "postfix")
{ name = "postfix";
description = "Postfix mail server user";
uid = config.ids.uids.postfix;
group = group;
};
users.groups =
optional (group == "postfix")
{ name = group;
gid = config.ids.gids.postfix;
}
++ optional (setgidGroup == "postdrop")
{ name = setgidGroup;
gid = config.ids.gids.postdrop;
};
systemd.services.postfix =
{ description = "Postfix mail server";
wantedBy = [ "multi-user.target" ];
after = [ "network.target" ];
path = [ pkgs.postfix ];
serviceConfig = {
Type = "forking";
Restart = "always";
PIDFile = "/var/lib/postfix/queue/pid/master.pid";
ExecStart = "${pkgs.postfix}/bin/postfix start";
ExecStop = "${pkgs.postfix}/bin/postfix stop";
ExecReload = "${pkgs.postfix}/bin/postfix reload";
};
preStart = ''
# Backwards compatibility
if [ ! -d /var/lib/postfix ] && [ -d /var/postfix ]; then
mkdir -p /var/lib
mv /var/postfix /var/lib/postfix
fi
# All permissions set according ${pkgs.postfix}/etc/postfix/postfix-files script
mkdir -p /var/lib/postfix /var/lib/postfix/queue/{pid,public,maildrop}
chmod 0755 /var/lib/postfix
chown root:root /var/lib/postfix
rm -rf /var/lib/postfix/conf
mkdir -p /var/lib/postfix/conf
chmod 0755 /var/lib/postfix/conf
ln -sf ${pkgs.postfix}/etc/postfix/postfix-files /var/lib/postfix/conf/postfix-files
ln -sf ${mainCfFile} /var/lib/postfix/conf/main.cf
ln -sf ${masterCfFile} /var/lib/postfix/conf/master.cf
${concatStringsSep "\n" (mapAttrsToList (to: from: ''
ln -sf ${from} /var/lib/postfix/conf/${to}
${pkgs.postfix}/bin/postalias /var/lib/postfix/conf/${to}
'') cfg.aliasFiles)}
${concatStringsSep "\n" (mapAttrsToList (to: from: ''
ln -sf ${from} /var/lib/postfix/conf/${to}
${pkgs.postfix}/bin/postmap /var/lib/postfix/conf/${to}
'') cfg.mapFiles)}
mkdir -p /var/spool/mail
chown root:root /var/spool/mail
chmod a+rwxt /var/spool/mail
ln -sf /var/spool/mail /var/
#Finally delegate to postfix checking remain directories in /var/lib/postfix and set permissions on them
${pkgs.postfix}/bin/postfix set-permissions config_directory=/var/lib/postfix/conf
'';
};
services.postfix.config = (mapAttrs (_: v: mkDefault v) {
compatibility_level = "9999";
mail_owner = cfg.user;
default_privs = "nobody";
# NixOS specific locations
data_directory = "/var/lib/postfix/data";
queue_directory = "/var/lib/postfix/queue";
# Default location of everything in package
meta_directory = "${pkgs.postfix}/etc/postfix";
command_directory = "${pkgs.postfix}/bin";
sample_directory = "/etc/postfix";
newaliases_path = "${pkgs.postfix}/bin/newaliases";
mailq_path = "${pkgs.postfix}/bin/mailq";
readme_directory = false;
sendmail_path = "${pkgs.postfix}/bin/sendmail";
daemon_directory = "${pkgs.postfix}/libexec/postfix";
manpage_directory = "${pkgs.postfix}/share/man";
html_directory = "${pkgs.postfix}/share/postfix/doc/html";
shlib_directory = false;
mail_spool_directory = "/var/spool/mail/";
setgid_group = cfg.setgidGroup;
})
// optionalAttrs (cfg.relayHost != "") { relayhost = if cfg.lookupMX
then "${cfg.relayHost}:${toString cfg.relayPort}"
else "[${cfg.relayHost}]:${toString cfg.relayPort}"; }
// optionalAttrs config.networking.enableIPv6 { inet_protocols = mkDefault "all"; }
// optionalAttrs (cfg.networks != null) { mynetworks = cfg.networks; }
// optionalAttrs (cfg.networksStyle != "") { mynetworks_style = cfg.networksStyle; }
// optionalAttrs (cfg.hostname != "") { myhostname = cfg.hostname; }
// optionalAttrs (cfg.domain != "") { mydomain = cfg.domain; }
// optionalAttrs (cfg.origin != "") { myorigin = cfg.origin; }
// optionalAttrs (cfg.destination != null) { mydestination = cfg.destination; }
// optionalAttrs (cfg.relayDomains != null) { relay_domains = cfg.relayDomains; }
// optionalAttrs (cfg.recipientDelimiter != "") { recipient_delimiter = cfg.recipientDelimiter; }
// optionalAttrs haveAliases { alias_maps = [ "${cfg.aliasMapType}:/etc/postfix/aliases" ]; }
// optionalAttrs haveTransport { transport_maps = [ "hash:/etc/postfix/transport" ]; }
// optionalAttrs haveVirtual { virtual_alias_maps = [ "${cfg.virtualMapType}:/etc/postfix/virtual" ]; }
// optionalAttrs (cfg.dnsBlacklists != []) { smtpd_client_restrictions = clientRestrictions; }
// optionalAttrs cfg.useSrs {
sender_canonical_maps = [ "tcp:127.0.0.1:10001" ];
sender_canonical_classes = [ "envelope_sender" ];
recipient_canonical_maps = [ "tcp:127.0.0.1:10002" ];
recipient_canonical_classes = [ "envelope_recipient" ];
}
// optionalAttrs cfg.enableHeaderChecks { header_checks = [ "regexp:/etc/postfix/header_checks" ]; }
// optionalAttrs (cfg.sslCert != "") {
smtp_tls_CAfile = cfg.sslCACert;
smtp_tls_cert_file = cfg.sslCert;
smtp_tls_key_file = cfg.sslKey;
smtp_use_tls = true;
smtpd_tls_CAfile = cfg.sslCACert;
smtpd_tls_cert_file = cfg.sslCert;
smtpd_tls_key_file = cfg.sslKey;
smtpd_use_tls = true;
};
services.postfix.masterConfig = {
smtp_inet = {
name = "smtp";
type = "inet";
private = false;
command = "smtpd";
};
pickup = {
private = false;
wakeup = 60;
maxproc = 1;
};
cleanup = {
private = false;
maxproc = 0;
};
qmgr = {
private = false;
wakeup = 300;
maxproc = 1;
};
tlsmgr = {
wakeup = 1000;
wakeupUnusedComponent = false;
maxproc = 1;
};
rewrite = {
command = "trivial-rewrite";
};
bounce = {
maxproc = 0;
};
defer = {
maxproc = 0;
command = "bounce";
};
trace = {
maxproc = 0;
command = "bounce";
};
verify = {
maxproc = 1;
};
flush = {
private = false;
wakeup = 1000;
wakeupUnusedComponent = false;
maxproc = 0;
};
proxymap = {
command = "proxymap";
};
proxywrite = {
maxproc = 1;
command = "proxymap";
};
showq = {
private = false;
};
error = {};
retry = {
command = "error";
};
discard = {};
local = {
privileged = true;
};
virtual = {
privileged = true;
};
lmtp = {
};
anvil = {
maxproc = 1;
};
scache = {
maxproc = 1;
};
} // optionalAttrs cfg.enableSubmission {
submission = {
type = "inet";
private = false;
command = "smtpd";
args = let
mkKeyVal = opt: val: [ "-o" (opt + "=" + val) ];
in concatLists (mapAttrsToList mkKeyVal cfg.submissionOptions);
};
} // optionalAttrs cfg.enableSmtp {
smtp = {};
relay = {
command = "smtp";
args = [ "-o" "smtp_fallback_relay=" ];
};
};
}
(mkIf haveAliases {
services.postfix.aliasFiles."aliases" = aliasesFile;
})
(mkIf haveTransport {
services.postfix.mapFiles."transport" = transportFile;
})
(mkIf haveVirtual {
services.postfix.mapFiles."virtual" = virtualFile;
})
(mkIf cfg.enableHeaderChecks {
services.postfix.mapFiles."header_checks" = headerChecksFile;
})
(mkIf (cfg.dnsBlacklists != []) {
services.postfix.mapFiles."client_access" = checkClientAccessFile;
})
]);
}