nixpkgs/nixos/modules/services/security/tor.nix

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{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.services.tor;
torDirectory = "/var/lib/tor";
opt = name: value: optionalString (value != null) "${name} ${value}";
optint = name: value: optionalString (value != 0) "${name} ${toString value}";
torRc = ''
User tor
DataDirectory ${torDirectory}
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${optionalString cfg.enableGeoIP ''
GeoIPFile ${pkgs.tor.geoip}/share/tor/geoip
GeoIPv6File ${pkgs.tor.geoip}/share/tor/geoip6
''}
${optint "ControlPort" cfg.controlPort}
''
# Client connection config
+ optionalString cfg.client.enable ''
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SOCKSPort ${cfg.client.socksListenAddress} IsolateDestAddr
SOCKSPort ${cfg.client.socksListenAddressFaster}
${opt "SocksPolicy" cfg.client.socksPolicy}
''
# Relay config
+ optionalString cfg.relay.enable ''
ORPort ${cfg.relay.portSpec}
${opt "Nickname" cfg.relay.nickname}
${opt "ContactInfo" cfg.relay.contactInfo}
${optint "RelayBandwidthRate" cfg.relay.bandwidthRate}
${optint "RelayBandwidthBurst" cfg.relay.bandwidthBurst}
${opt "AccountingMax" cfg.relay.accountingMax}
${opt "AccountingStart" cfg.relay.accountingStart}
${if cfg.relay.isExit then
opt "ExitPolicy" cfg.relay.exitPolicy
else
"ExitPolicy reject *:*"}
${optionalString cfg.relay.isBridge ''
BridgeRelay 1
ServerTransportPlugin obfs2,obfs3 exec ${pkgs.pythonPackages.obfsproxy}/bin/obfsproxy managed
''}
''
+ cfg.extraConfig;
torRcFile = pkgs.writeText "torrc" torRc;
in
{
options = {
services.tor = {
enable = mkOption {
type = types.bool;
default = false;
description = ''
Enable the Tor daemon. By default, the daemon is run without
relay, exit, bridge or client connectivity.
'';
};
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enableGeoIP = mkOption {
type = types.bool;
default = true;
description = ''
Whenever to configure Tor daemon to use GeoIP databases.
Disabling this will disable by-country statistics for
bridges and relays and some client and third-party software
functionality.
'';
};
extraConfig = mkOption {
type = types.lines;
default = "";
description = ''
Extra configuration. Contents will be added verbatim to the
configuration file at the end.
'';
};
controlPort = mkOption {
type = types.int;
default = 0;
example = 9051;
description = ''
If set, Tor will accept connections on the specified port
and allow them to control the tor process.
'';
};
client = {
enable = mkOption {
type = types.bool;
default = false;
description = ''
Whether to enable Tor daemon to route application
connections. You might want to disable this if you plan
running a dedicated Tor relay.
'';
};
socksListenAddress = mkOption {
type = types.str;
default = "127.0.0.1:9050";
example = "192.168.0.1:9100";
description = ''
Bind to this address to listen for connections from
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Socks-speaking applications. Provides strong circuit
isolation, separate circuit per IP address.
'';
};
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socksListenAddressFaster = mkOption {
type = types.str;
default = "127.0.0.1:9063";
example = "192.168.0.1:9101";
description = ''
Bind to this address to listen for connections from
Socks-speaking applications. Same as socksListenAddress
but uses weaker circuit isolation to provide performance
suitable for a web browser.
'';
};
socksPolicy = mkOption {
type = types.nullOr types.str;
default = null;
example = "accept 192.168.0.0/16, reject *";
description = ''
Entry policies to allow/deny SOCKS requests based on IP
address. First entry that matches wins. If no SocksPolicy
is set, we accept all (and only) requests from
SocksListenAddress.
'';
};
privoxy.enable = mkOption {
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type = types.bool;
default = true;
description = ''
Whether to enable and configure the system Privoxy to use Tor's
faster port, suitable for HTTP.
To have anonymity, protocols need to be scrubbed of identifying
information, and this can be accomplished for HTTP by Privoxy.
Privoxy can also be useful for KDE torification. A good setup would be:
setting SOCKS proxy to the default Tor port, providing maximum
circuit isolation where possible; and setting HTTP proxy to Privoxy
to route HTTP traffic over faster, but less isolated port.
'';
};
};
relay = {
enable = mkOption {
type = types.bool;
default = false;
description = ''
Whether to enable relaying TOR traffic for others.
See https://www.torproject.org/docs/tor-doc-relay for details.
'';
};
isBridge = mkOption {
type = types.bool;
default = false;
description = ''
Bridge relays (or "bridges") are Tor relays that aren't
listed in the main directory. Since there is no complete
public list of them, even if an ISP is filtering
connections to all the known Tor relays, they probably
won't be able to block all the bridges.
A bridge relay can't be an exit relay.
You need to set relay.enable to true for this option to
take effect.
The bridge is set up with an obfuscated transport proxy.
See https://www.torproject.org/bridges.html.en for more info.
'';
};
isExit = mkOption {
type = types.bool;
default = false;
description = ''
An exit relay allows Tor users to access regular Internet
services.
Unlike running a non-exit relay, running an exit relay may
expose you to abuse complaints. See
https://www.torproject.org/faq.html.en#ExitPolicies for
more info.
You can specify which services Tor users may access via
your exit relay using exitPolicy option.
'';
};
nickname = mkOption {
type = types.str;
default = "anonymous";
description = ''
A unique handle for your TOR relay.
'';
};
contactInfo = mkOption {
type = types.nullOr types.str;
default = null;
example = "admin@relay.com";
description = ''
Contact information for the relay owner (e.g. a mail
address and GPG key ID).
'';
};
accountingMax = mkOption {
type = types.nullOr types.str;
default = null;
example = "450 GBytes";
description = ''
Specify maximum bandwidth allowed during an accounting
period. This allows you to limit overall tor bandwidth
over some time period. See the
<literal>AccountingMax</literal> option by looking at the
tor manual (<literal>man tor</literal>) for more.
Note this limit applies individually to upload and
download; if you specify <literal>"500 GBytes"</literal>
here, then you may transfer up to 1 TBytes of overall
bandwidth (500 GB upload, 500 GB download).
'';
};
accountingStart = mkOption {
type = types.nullOr types.str;
default = null;
example = "month 1 1:00";
description = ''
Specify length of an accounting period. This allows you to
limit overall tor bandwidth over some time period. See the
<literal>AccountingStart</literal> option by looking at
the tor manual (<literal>man tor</literal>) for more.
'';
};
bandwidthRate = mkOption {
type = types.int;
default = 0;
example = 100;
description = ''
Specify this to limit the bandwidth usage of relayed (server)
traffic. Your own traffic is still unthrottled. Units: bytes/second.
'';
};
bandwidthBurst = mkOption {
type = types.int;
default = cfg.relay.bandwidthRate;
example = 200;
description = ''
Specify this to allow bursts of the bandwidth usage of relayed (server)
traffic. The average usage will still be as specified in relayBandwidthRate.
Your own traffic is still unthrottled. Units: bytes/second.
'';
};
portSpec = mkOption {
type = types.str;
example = "143";
description = ''
What port to advertise for Tor connections. This corresponds
to the <literal>ORPort</literal> section in the Tor manual; see
<literal>man tor</literal> for more details.
At a minimum, you should just specify the port for the
relay to listen on; a common one like 143, 22, 80, or 443
to help Tor users who may have very restrictive port-based
firewalls.
'';
};
exitPolicy = mkOption {
type = types.nullOr types.str;
default = null;
example = "accept *:6660-6667,reject *:*";
description = ''
A comma-separated list of exit policies. They're
considered first to last, and the first match wins. If you
want to _replace_ the default exit policy, end this with
either a reject *:* or an accept *:*. Otherwise, you're
_augmenting_ (prepending to) the default exit
policy. Leave commented to just use the default, which is
available in the man page or at
https://www.torproject.org/documentation.html
Look at https://www.torproject.org/faq-abuse.html#TypicalAbuses
for issues you might encounter if you use the default exit policy.
If certain IPs and ports are blocked externally, e.g. by
your firewall, you should update your exit policy to
reflect this -- otherwise Tor users will be told that
those destinations are down.
'';
};
};
};
};
config = mkIf cfg.enable {
assertions = singleton
{ message = "Can't be both an exit and a bridge relay at the same time";
assertion =
cfg.relay.enable -> !(cfg.relay.isBridge && cfg.relay.isExit);
};
users.extraGroups.tor.gid = config.ids.gids.tor;
users.extraUsers.tor =
{ description = "Tor Daemon User";
createHome = true;
home = torDirectory;
group = "tor";
uid = config.ids.uids.tor;
};
systemd.services.tor =
{ description = "Tor Daemon";
path = [ pkgs.tor ];
wantedBy = [ "multi-user.target" ];
after = [ "network.target" ];
restartTriggers = [ torRcFile ];
# Translated from the upstream contrib/dist/tor.service.in
serviceConfig =
{ Type = "simple";
ExecStartPre = "${pkgs.tor}/bin/tor -f ${torRcFile} --verify-config";
ExecStart = "${pkgs.tor}/bin/tor -f ${torRcFile} --RunAsDaemon 0";
ExecReload = "${pkgs.coreutils}/bin/kill -HUP $MAINPID";
KillSignal = "SIGINT";
TimeoutSec = 30;
Restart = "on-failure";
LimitNOFILE = 32768;
# Hardening
# Note: DevicePolicy is set to 'closed', although the
# minimal permissions are really:
# DeviceAllow /dev/null rw
# DeviceAllow /dev/urandom r
# .. but we can't specify DeviceAllow multiple times. 'closed'
# is close enough.
PrivateTmp = "yes";
DevicePolicy = "closed";
InaccessibleDirectories = "/home";
ReadOnlyDirectories = "/";
ReadWriteDirectories = torDirectory;
NoNewPrivileges = "yes";
};
};
environment.systemPackages = [ pkgs.tor ];
services.privoxy = mkIf (cfg.client.enable && cfg.client.privoxy.enable) {
enable = true;
extraConfig = ''
forward-socks4a / ${cfg.client.socksListenAddressFaster} .
toggle 1
enable-remote-toggle 0
enable-edit-actions 0
enable-remote-http-toggle 0
'';
};
};
}