Verbana: Verification and banning mod for Minetest

Copyright flux 2021 AGPLv3

Name

A portmanteau of "verification", "ban", and the herb verbena.

Terminology

The terms network and ASN are used interchangeably in this document.

The terms player and account are also used interchangeably in most contexts; sometimes player will refer to a physical person, however.

Motivation

This mod is a response to sban, an IP-aware banning mod derived from xban, and BillyS's verification mod for Blocky Survival. Both of these mods have problems that I've long wanted to resolve, and it seemed the best resolution to those problems was to create a new integrating the features of both.

Sban is a good first attempt at IP-aware bans, but it has several major flaws:

1. Multiple users may be associated with an IP, and banning one often bans them all.
2. Banned IPs can still "hack" into existing accounts of other players by brute-forcing weak passwords.
3. For many trolls, getting access to a new IP is far too easy, and there is no effective way to keep them off the server.

BillyS's verification mod was created to deal with one particular troll on the BlockySurvival server, who repeatedly got around sban by getting new IPs from VPNs and his regular mobile service provider. When enabled, it requires all new players to be verified by a player with moderator privileges before they can interact with the server or communicate with non-moderator players.

The flaws in the verification mod are

1. Verification is all-or-nothing; either all new players require verification, or none of them do.
2. Moderators are not always online to verify new players.
3. New players come from all over the world, and may not be able to communicate with the moderator.
4. New players are of all ages, and may not be able to communicate in chat at all.

Verbana aims to provide name-based banning, as well as ip and network based blocking and verification.

1. IPs and Networks may be marked as "untrusted" - all new players from untrusted IPs/networks must go through verification, while other new players may join at will.
2. A "verification jail" can optionally be specified, which prevents unverified players from getting loose on the server.
3. IPs and Networks may be blocked or temporarily blocked, should the need arise.

Some features of sban that the first release of Verbana will likely lack:

• A GUI. The sban GUI does not work particularly well anyway, and I don't know formspec. Use commands.
• Import/export from various other ban formats. I plan to import data from sban, but I don't have a use case for the rest. However, if someone wants to write a module to import from e.g. xban2, be my guest.

Requirements

• Minetest 5.0 or later.
• Verbana must be listed as a trusted mod in minetest.conf (secure.trusted_mods), in order to use a sqlite database.
• lsqlite3 (SQLite3 for Lua) must be installed and accessible to Minetest's Lua.
• The easiest way I know how to do this: install luarocks, and execute luarocks --lua-version 5.1 install lsqlite3 or the appropriate variation.
• The Minetest server must use IPv4 exclusively. I've made zero attempt to support IPv6.
• There's some soft dependencies on linux. Windows users may need to make some changes, which I would gladly accept as a PR.

Optional Dependencies

Verbana can make use of the stock IRC mod, as well as the "IRC2" mod that is used on the Blocky Survival server to connect to a second IRC server.

Sban and verification are also listed as optional dependencies, but this is primarily in order for verbana to detect their presence. By default, verbana will run in "debug mode" if these mods are detected. If you wish to use verbana as intended, you do *not* want these mods installed.

Installation

If you don't know the basics of installing a minetest mod, please see

• https://wiki.minetest.net/Installing_Mods
• https://dev.minetest.net/Installing_Mods

Trust the mod

Verbana must be marked as a trusted mod, with a line like the following added to minetest.conf:

secure.trusted_mods = verbana

The only "trusted" thing verbana does is load lsqlite so that it can interact with its database. To our knowledge, verbana cannot leak the insecure environment, but it can leak the lsqlite interface in minetest 5.0.1 and development versions before commit ecd20de.

Download ASN tables

Once you have put the verbana mod in the correct place, you will need to download the ASN tables that verbana uses to correlate IP numbers with networks. On Linux systems, you should just be able to run the script update_tables.sh. On other systems, you will need to find another way to download those files, and convert the data-used-autnums file from ths ISO-8859-1 encoding to utf8.

The ASN tables update regularly, though for the most part nothing major changes. You should put a process in place that updates these automatically (or manually) some period between daily and monthly.

Configuration

The following configuration options are available, and can be set in your minetest.conf file.

• verbana.db_path

  The location verbana will store its database. Defaults to ${WORLD_ROOT}/verbana.sqlite.

• verbana.asn_description_path

  The location of the ASN description file. Defaults to ${MOD_ROOT}/data-used-autnums

• verbana.asn_data_path

  The location of the ASN data file. Defaults to ${MOD_ROOT}/data-raw-table

• verbana.admin_priv

  The privilege needed to administer verbana. Defaults to ban_admin. This privilege will be created if it does not currently exist.

• verbana.moderator_priv

  The privilege needed to use verbana for moderation. Defaults to ban. This privilege will be created if it does not currently exist.

• verbana.kick_priv

  The privilege needed to kick users. By default, the moderator privilege will be used. If you want a separate privilege just for kicking, you can set this value. Usually you'll want to give it the value "kick".

• verbana.unverified_privs

  The privileges granted to users with the "unverified" status. Defaults to shout. If there are multiple privileges, they should be comma-delimited.

• default_privs

  This is a core setting, not a verbana-specific one. Verbana uses it to determine what privileges to give to players once they are verified. Defaults to shout,interact. If there are multiple privileges, they should be comma-delimited.

• verbana.whitelisted_privs

  A list of privileges that are equivalent to the whitelisted status. If a player has all of the listed privileges, they skip the suspicious network checks on login. By default, it is blank i.e. disabled.

• static_spawnpoint

  This is a core setting, not a verbana-specific one. Verbana uses this to determine where a normal (verified) player will spawn, and where to move players that are newly verified. It is a list of coordinates (x,y,z), and defaults to (0,0,0).

• verbana.unverified_spawn_pos

  Coordinates where unverified players will spawn. It is a list of coordinates (x,y,z) and defaults to the value of static_spawnpoint.

• verbana.jail_bounds

  Boundaries for the verification "jail" area, if one exists. It needs to be specified as a pair of coordinates, (x1,y1,z1),(x2,y2,z2), that specify the 3d bounding box of the jail. If a jail is defined, verbana.unverified_spawn_pos should be inside of the jail, or unexpected behavior may result.

• verbana.jail_check_period

  A period, specified in seconds, between checks of whether an unverified player has escaped the verification jail. It defaults to 0, which disables the jail.

  Both verbana.jail_bounds and verbana.jail_check_period must be defined in order for the verification jail to be enabled.

• verbana.universal_verification

  If set to true, all new users must be verified. Otherwise, only players from suspicious networks need be verified. Defaults to false

• verbana.debug_mode

  Whether to run verbana in debug mode. By default, verbana will run in debug mode if the sban or verification mod are installed and enabled. Setting this will override that behavior, if that is desired.

  In debug mode, verbana will (1) reload the schema on every server startup (2) automatically import data from sban, if its DB is found (3) not make any changes to player privileges (4) not block any users from connecting to the server (5) not kick any users from the server.

Functionality

Verbana assigns a "status" to all players, IPs, and networks that determines in what cases players can connect to the server.

Player Status

• default

  Most players will have the default status.

• banned

  A player who has been banned will not be able to connect to the server. Note that banning one account does not generally prevent other accounts from connecting from IPs or Networks that the user has been associated with. However, it will temporarily mark the last-known IP of the user as suspicious.

• unverified

  A new player that connects from a suspicious IP or network is automatically marked as unverified. Unverified users have reduced privileges (by default, they lack interact), and must be verified by a verbana admin or moderator before they can play the game or communicate with ordinary players.

• suspicious

  A player that has been marked as suspicious has no real restrictions, but verbana moderators and admins will be alerted when the player logs in or performs certain other actions.

• whitelisted

  A player that has been whitelisted will be allowed to bypass the suspicious network checks when they join the server.

IP status

• default

  Most IPs will have the default status.

• blocked

  All connections from blocked IPs will be denied, except for whitelisted players.

• suspicious

  A new player connecting from a suspicious IP will be forced to go through verification, unless the player is whitelisted. An attempt to connect from a suspicious IP as an existing player will be denied, if that player has never connected from that network before.

• trusted

  An IP in a suspicious network may be marked as trusted, which indicates that connections from that IP will bypass suspicious network checks.

ASN status

• default

  Most networks will have the default status.

• blocked

  All connections from this network will be denied, unless the player is whitelisted or the IP is trusted.

• suspicious

  A new player connecting from a suspicious network will be forced to go through verification, unless the player is whitelisted. An attempt to connect from a suspicious network as an existing player will be denied, if that player has never connected from that network before.

Master accounts and alts

It is possible to link accounts together in a master/alt account relationship. In such a relationship, changes in the status to one account will be reflected by them all. This can be used to associate new accounts w/ existing accounts that are banned, to quickly ban those accounts.

An account can have only one master. A master account cannot have another account as its master; you can't chain the master/alt relationship.

Flagged accounts

Accounts that have been banned, kicked, unverified, or marked as suspicious retain a separate "flagged" status, which is used to restrict the output of certain other commands.

Commands

Arguments in angle brackets "<player_name>" are mandatory. Arguments in square brackets are optional e.g. "[<filename>]". Some optional arguments have default values e.g. [<timespan>=1w].

Administration

These commands are available only to administrators.

• sban_import [<filename>]

  Import data from the sban database. If no filename is specified, it looks for the DB in its default location, $WORLD_ROOT/sban.sqlite

• verification on | off

  Turn universal verification on or off. When universal verification is on, all new players must be verified before they can interact with the server.

Available to all players

These commands are available to all players

• report <message>

  Create a "report" that admins and moderators can read. Players can use this to communicate problems to staff if staff is not currently around.

• first-login <player_name>

  Get the original login date for an account. Corresponds to /last-login

General status

General query commands for verbana staff.

• reports [<timespan>=1w]

  Show recent reports.

• bans [<number>=20]

  Show recent bans.

• who2

  Show currently connected players, along with IPs, networks, and statuses.

Player inspection

Commands for looking up info about a player or players. All queries involving a player name are case-insensitive.

• pgrep <pattern> [<limit>=20]

  Search for player accounts that match a certain "pattern". The pattern is a glob-type pattern, e.g. flux will search for any player name containing the string "flux".

• asn <player_name> | <IP>

  Look up the network of a player (currently connected or not) or an IP.

• cluster <player_name>

  Get a list of other player accounts that have used an IP that the given player has used.

• status <player_name> [<number>=20]

  Get the most recent status changes for a player.

• inspect <player_name>

  Get a list of IPs and networks associated with a player.

• logins <player_name> [<number>=20]

  View the most recent login info of a player.

• alts <player_name>

  List the registered alt accounts associated with a player.

• ban_record <player_name>

  Get a summary of important information about a player, including other accounts associated by IP, flagged accounts associated by network, and their status log.

Player management

Commands to change the status of a player.

• kick <player_name> [<reason>]

  Kick a player from the server. Kicks go into the player's status log, but do not alter the player's status.

• ban <player_name> [<timespan>] [<reason>]

  Ban a player. If a timespan is given e.g. 3d (three days) or 1w (one week) then the ban is temporary, and will expire after the given time. Banning has the side effect of marking the most recently used IP of the player as suspicious.

• unban <player_name> [<reason>]

  Unban a player.

• suspect <player_name> [<reason>]

  Mark a player as suspicious. Suspicious players have the same privileges as regular players, but certain actions e.g. logging in, are reported to verbana staff.

• unsuspect <player_name> [<reason>]

  Remove a player's suspicious status.

• verify <player_name> [<reason>]

  Verify an unverified player.

• unverify <player_name> [<reason>]

  Reset a player's "unverified" status. This will revoke their ability to interact or communicate with non-staff players. If a verification jail is defined, the player will be returned to the verification jail.

• whitelist <player_name> [<reason>]

  An admin command. Mark a certain account as whitelisted, which allows it to bypass the suspicious network checks at login.

• unwhitelist <player_name> [<reason>]

  Remove a player's whitelisted status.

Managing account clusters

• master <alt> <master>

  Associate an alt account with a master account.

• unmaster <player_name>

  Remove the associated master account for a given alt.

• unflag <player_name>

  Remove the "flag" from an account.

IP inspection

• ip_inspect <IP> [<timespan>=1w]

  List players and statuses associated with an IP.

• ip_status <IP> [<number>]

  List the status of an IP.

IP management

• ip_block <IP> [<timespan>] [<reason>]

  Block an IP, with an optional timespan. No connections from this IP will be allowed.

• ip_unblock <IP> [<reason>]

  Unblock an IP.

• ip_suspect <IP> [<reason>]

  Mark an IP as suspicious. New players connecting from this IP will be forced to go through manual verification.

• ip_unsuspect <IP> [<reason>]

  Remove the supicious status from an IP.

• ip_trust <IP> [<reason>]

  Mark an IP as trusted. Connections from a trusted IP that is part of a suspicious network will bypass the suspicious network checks.

• ip_untrust <IP> [<reason>]

  Unmark an IP as suspicious.

ASN inspection

• asn_inspect <ASN> [<timespan>=1y]

  Show flagged accounts associated with the network.

• asn_status <ASN> [<number>]

  Show the status log for the network.

• asn_stats <ASN>

  Show some statistics for the usage of the network.

ASN management

• asn_block <ASN> [<timespan>] [<reason>]

  Block all connections from the network.

• asn_unblock <ASN> [<reason>]

  Unblock connections from the network.

• asn_suspect <ASN> [<reason>]

  Mark the network as suspicious.

• asn_unsuspect <ASN> [<reason>]

  Unmark the network as suspicious.