nusenu / Ansible Relayor

ansible-relayor

This is an ansible role for tor relay operators. An introduction to relayor can be found here.

Email Support: relayor-support AT riseup.net

The main focus of this role is to automate as many steps as possible for a tor relay operator including key management (OfflineMasterKey). Deploying a new tor server is as easy as adding a new host to the inventory, no further manual configuration is required.

Keeping the tor package updated (an important task of running a relay) is not in scope of this ansible role. We recommend you enable automatic updates to keep your relay well maintained if your OS supports that. The Tor Relay Guide contains instructions on how to enable automatic software updates.

This ansible role does not aim to support tor bridges.

Main benefits for a tor relay operator

• automation - no more manual setup tasks
• security: offline Ed25519 master keys are generated on the ansible host and are never exposed to the relay
• easy Ed25519 signing key renewal (valid for 30 days by default - configurable)
• security: compartmentalization: every tor instance is run with a distinct user
• automatically makes use of IPv6 IPs (if available)
• automatic tor instance generation (two by default - configurable)
• enables tor's Sandbox feature by default on Debian-based systems
• easily choose between alpha/non-alpha releases (Debian/Ubuntu/FreeBSD only)
• easily restore a relay setup (the ansible host becomes a backup location for all keys out of the box)
• easily choose between exit relay/non-exit relay mode using a single boolean
• automatic deployment of a tor exit notice html page via tor's DirPort (on exits only)
• automatic MyFamily management

Installation

This ansible role is available on galaxy https://galaxy.ansible.com/nusenu/relayor/

ansible-galaxy install nusenu.relayor

Requirements

Control Machine Requirements

• do not run this role with become: yes
• tor >= 0.3.5
• python-netaddr package must be installed
• required commands: sort, uniq, wc, cut, sed, xargs
• openssl >= 1.0.0
• ansible >= 2.9.12
• bash under /bin/bash

Managed Node Requirements

• a non-root user with sudo permissions
• python
• static IPv4 address(es)
  • we can use multiple public IPs
  • if you have no public IP we will use a single private IP (and assume NAT)
• systemd (all Linux-based systems)

Supported Operating Systems

• Debian 9 and 10
• OpenBSD 6.8
• FreeBSD 11.4, 12.2
• Ubuntu 20.04

Supported Tor Releases

• tor >= 0.3.5.x

Example Playbook

A minimal playbook using ansible-relayor to setup non-exit relays could look like this:

---

- hosts: relays
  vars:
    tor_ContactInfo: [email protected]
  roles:
    - nusenu.relayor

For more examples see the playbook-examples folder.

Role Variables

All variables mentioned here are optional.

• tor_ContactInfo string

  • Sets the relay's ContactInfo field.
  • This setting is mandatory.
  • Operators are encouraged to use the ContactInfo Information Sharing Specification to publish useful contact information.

• tor_signingkeylifetime_days integer

  • all tor instances created by relayor run in OfflineMasterKey mode
  • this setting defines the lifetime of Ed25519 signing keys in days
  • indirectly defines how often you have to run your ansible playbook to ensure your relay keys do not expire
  • a tor instance in OfflineMasterKey mode automatically stops when his key/cert expires, so this is a crucial setting!
  • lower values (eg. 7) are better from a security point of view but require more frequent playbook runs
  • default: 30

• tor_ports

  • This var allows you to
    • select tor's ORPort and DirPort
    • reduce the number of Tor instances created per IP address
  • disable DirPorts by setting them to 0
  • tor's 'auto' feature is NOT supported
  • HINT: choose them wisely and never change them again ;)
  • NOTE: on SELinux-enabled systems you must choose from the following ports:
  • 80, 81, 443, 488, 6969, 8008, 8009, 8443, 9000, 9001, 9030, 9050, 9051, 9150
  • default:
    • instance 1: ORPort 9000, DirPort 9001
    • instance 2: ORPort 9100, DirPort 9101

• tor_offline_masterkey_dir

  • default: ~/.tor/offlinemasterkeys
  • Defines the location where on the ansible control machine we store relay keys (Ed25519 and RSA)
  • Within that folder ansible will create a subfolder for every tor instance.
  • see the documentation if you want to migrate instances to a new server
  • note: do not manually mangle file and/or foldernames/content in these tor DataDirs

• tor_nickname string

  • defines the nickname tor instances will use
  • all tor instances on a host will get the same nickname
  • to use the server's hostname as the nickname set it to {{ ansible_hostname }}
  • non-alphanum chars are automatically removed and nicknames longer than 19 characters are truncated to meet tor's nickname requirements
  • tor_nicknamefile overrules this setting
  • default: none

• tor_nicknamefile /path/to/file.csv

  • this is a simple comma separated csv file stored on the ansible control machine specifying nicknames
  • first column: instance identifier (inventory_hostname-ip_orport)
  • second column: nickname
  • one instance per line
  • all instances MUST be present in the csv file
  • non-alphanum chars are automatically removed and nicknames longer than 19 characters are truncated to meet tor's nickname requirements
  • default: not set

• tor_Sandbox

  • enables (1) or disables (0) tor's syscall sandbox feature
  • this setting is ignored on non-Linux systems
  • unlike upstream tor we enable this by default on Debian-based systems which have a Linux kernel (>=3.5) that supports it.
  • default on Debian-based systems: 1 (others: 0)

• tor_NoExec

  • enables (1) or disables (0) tor's NoExec feature
  • unlike upstream we enable this by default (except on CentOS)
  • this option is not supported on CentOS
  • default: 1

• tor_alpha boolean

  • Set to True if you want to use Tor alpha version releases.
  • Note: This setting does not ensure an installed tor is upgraded to the alpha release.
  • This setting is supported on Debian/Ubuntu/FreeBSD only (ignored on other platforms).
  • default: False

• tor_nightly_builds boolean

  • Set to True if you want to use Tor nightly builds repo from deb.torproject.org.
  • nightly builds follow the tor git master branch.
  • Only supported on Debian and Ubuntu (ignored on other platforms).
  • default: False

• tor_ExitRelay boolean

  • You have to set this to True if you want to enable exiting for all or some tor instances on a server
  • If this var is not True this will be a non-exit relay
  • If you want to run a mixed server (exit and non-exit tor instances) use tor_ExitRelaySetting_file for per-instance configuration in additon to this var
  • default: False

• tor_ExitRelaySetting_file /path/to/file

  • this is a simple comma separated csv file stored on the ansible control machine defining the ExitRelay torrc setting for each tor instance (instead of server-wide)
  • first column: instance identifier (inventory_hostname-ip_orport)
  • second column: "exit" for exit tor instances, any other value (including empty) for non-exit tor instances
  • this var is ignored if tor_ExitRelay is False

• tor_RelayBandwidthRate_file /path/to/file

  • this is a simple comma separated csv file stored on the ansible control machine defining the RelayBandwidthRate torrc setting for each tor instance (instead of server-wide)
  • first column: instance identifier (inventory_hostname-ip_orport)
  • second column: value as accepted by RelayBandwidthRate (see tor manpage)

• tor_RelayBandwidthBurst_file /path/to/file

  • this is a simple comma separated csv file stored on the ansible control machine defining the RelayBandwidthBurst torrc setting for each tor instance (instead of server-wide)
  • first column: instance identifier (inventory_hostname-ip_orport)
  • second column: value as accepted by RelayBandwidthBurst (see tor manpage)

• tor_ExitNoticePage boolean

  • specifies whether we display the default tor exit notice html page on the DirPort
  • only relevant if we are an exit relay
  • default: True

• tor_exit_notice_file /path/to/file

  • path to a HTML file on the control machine that you would like to display (via the DirPort) instead of the default tor-exit-notice.html provided by the Tor Project
  • only relevant if we are an exit relay and if tor_ExitNoticePage is True

• tor_AbuseEmailAddress email-address

  • if set this email address is used on the tor exit notice html page published on the DirPort
  • you are encouraged to set it if you run an exit
  • only relevant if we are an exit relay
  • Note: if you use your own custom tor-exit-notice template this var is ignored if you do not include it in your template.
  • default: not set

• tor_ExitPolicy array

  • specify your custom exit policy
  • only relevant if tor_ExitRelay is True
  • see defaults/main.yml for an example on how to set it
  • default: reduced exit policy (https://trac.torproject.org/projects/tor/wiki/doc/ReducedExitPolicy)

• tor_ExitPolicy_file /path/to/file

  • this is a simple semicolon separated csv file stored on the ansible control machine defining the ExitPolicy torrc setting for each tor instance (instead of server-wide)
  • first column: instance identifier (inventory_hostname-ip_orport)
  • second column: value as accepted by ExitPolicy (see tor manpage)
  • example content: "myrelay-192.168.1.1_443;reject *:25,reject *:123"
  • only relevant if tor_ExitRelay is True
  • this can be combined with the tor_ExitPolicy setting and will override it (this is more specific)
  • only tor instances that you want to have a specific exit policy for are required to be listed in the file (others can be omitted)
  • default: not set

• tor_maxPublicIPs

  • Limits the amount of public IPs we will use to generate instances on a single host.
  • Indirectly limits the amount of instances we generate per host.
  • default: 1

• tor_IPv6 boolean

  • autodetects if you have IPv6 IPs and enables an IPv6 ORPort accordingly
  • you can opt-out by setting it to False
  • default: True

• tor_IPv6Exit boolean

  • enables IPv6 exit traffic
  • only relevant if tor_ExitRelay and tor_IPv6 are True and we have an IPv6 address
  • default: True (unlike tor's default)

• tor_dedicatedExitIP boolean

  • on exit relays only: use a distinct source IP address for traffic leaving the tor network (exit traffic)
  • this means tor will establish outbound exit connections on a separate IP(v4/v6) address (different from the IP announced in the consensus)
  • automatically configures the OutboundBindAddressExit tor feature (does not require you to manually specify the IP address to use)
  • we will use the public IPv4/IPv6 address(es) available directly after the IP addresses we use for tor ORPorts for OutboundBindAddressExit
  • to make use of this feature you need more public IPv4 or IPv6 addresses than tor_maxPublicIPs
  • if this condition is not met we will abort
  • manually specifying the IP address used by OutboundBindAddressExit is not supported
  • default: False

• tor_enableControlSocket boolean

  • if True create a ControlSocket file for every tor instance (i.e. to be used for nyx)
  • access control relies on filesystem permissions
  • to give a user access to a specific tor instance's controlsocket file you
  • have to add the user to the primary group of the tor instance
  • the path to the socket file(s) is /var/run/tor-instances/instance-id/control
  • this setting affects all instances on a given server
  • per instance configuration is not supported
  • default: False

• tor_freebsd_somaxconn

  • configure kern.ipc.somaxconn on FreeBSD
  • by default we increase this value to at least 1024
  • if the value is higher than that we do not touch it

• tor_freebsd_nmbclusters

  • configure kern.ipc.nmbclusters on FreeBSD
  • by default we increase this value to at least 30000
  • if the value is higher than that we do not touch it

• tor_package_state

  • specify what package state the tor package should have
  • possible values: present, latest (not supported on BSDs)
  • Note: The repository metadata is not updated, so setting this to latest does not give you any guarantees if it actually is the latest version.
  • default: present

• tor_additional_MyFamily

  • this variable is not needed if you manage all your relays with this ansible role.
  • if you have relays not managed with this role you must specify the comma separated list of unmanaged relay fingerprints in this variable so they get included in the generated torrc configuration
  • Note: You also need to manually add the list of fingerprints of your relayor managed relays to the unmanaged relay.
  • default: not set

This role supports most torrc options documented in the 'SERVER OPTIONS' section of tor's manual. Set them via 'tor_OptionName'. Have a look at templates/torrc if you want to have list of supported options.

Available Role Tags

Using ansible tags is optional but allows you to speed up playbook runs if you are managing many servers.

There are OS specific tags:

• debian (includes ubuntu)
• centos
• fedora
• freebsd
• openbsd

Task oriented tags:

• renewkey - takes care of renewing online Ed25519 keys only (assumes that tor instances are fully configured and running already)
• install - installs tor but does not start or enable it
• createdir - creates (empty) directories on the ansible host only, useful for migration
• reconfigure - regenerates torrc files and reloads tor (requires previously configured tor instances)

So if you have a big family and you are about to add an OpenBSD host you typically make two steps

1. install the new server by running only against the new server (-l) and only the os specific tag (openbsd)

   ansible-playbook yourplaybook.yml -l newserver --tags openbsd

2. then reconfigure all servers (MyFamily) by running the 'reconfigure' tag against all servers.

   ansible-playbook yourplaybook.yml --tags reconfigure

Security Considerations

This ansible role makes use of tor's OfflineMasterKey feature without requiring any manual configuration.

The offline master key feature exposes only a temporary signing key to the relay (valid for 30 days by default). This allows to recover from a complete server compromise without losing a relay's reputation (no need to bootstrap a new permanent master key from scratch).

Every tor instance is run with a distinct system user. A per-instance user has only access to his own (temporary) keys, but not to those of other instances. We do not ultimately trust every tor relay we operate (we try to perform input validation when we use relay provided data on the ansible host or another relay).

Be aware that the ansible control machine stores ALL your relay keys (RSA and Ed25519) - apply security measures accordingly.

Integration Testing

This ansible role comes with a .kitchen.yml file, that can be used to test relayor - using different configurations - against Vagrant Virtualbox machines. It is primarily used for development/integration testing (spot regressions) but you can also use it to get familiar with relayor in such a local playground environment. These tor relays will not join the network since they are only created for testing purposes.

kitchen will download Vagrant boxes from Vagrant cloud to create test VMs.

To get started install the required gem packages:

gem install test-kitchen kitchen-ansiblepush kitchen-vagrant

List available test instances with kitchen list.

Then you can run all tests or just select specific instances, for example: kitchen test t-guard-debian-10.

Note that to run tests, you also need Vagrant and VirtualBox.

Origins

https://github.com/david415/ansible-tor (changed significantly since then)