118 lines
4.7 KiB
Plaintext
118 lines
4.7 KiB
Plaintext
// This file is using JSONNET, a complete configuration language based on JSON
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// See https://jsonnet.org
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// JSONNET is a superset of JSON, so one can write plain JSON files if wanted.
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// Note that YAML is also supported, see ./example.yml
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// A JSONNET function
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local iptables(args) = ['ip46tables', '-w'] + args;
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// variables defined for later use.
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local iptablesban = iptables(['-A', 'reaction', '1', '-s', '<ip>', '-j', 'drop']);
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local iptablesunban = iptables(['-D', 'reaction', '1', '-s', '<ip>', '-j', 'drop']);
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// ip46tables is a minimal C program (only POSIX dependencies) present as a subdirectory.
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// it permits to handle both ipv4/iptables and ipv6/ip6tables commands
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{
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// patterns are substitued in regexes.
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// when a filter performs an action, it replaces the found pattern
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patterns: {
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ip: {
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// reaction regex syntax is defined here: https://github.com/google/re2/wiki/Syntax
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// jsonnet's @'string' is for verbatim strings
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regex: @'(?:(?:[0-9]{1,3}\.){3}[0-9]{1,3})|(?:[0-9a-fA-F:]{2,90})',
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ignore: ['127.0.0.1', '::1'],
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},
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},
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// Those commands will be executed in order at start, before everything else
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start: [
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// Create an iptables chain for reaction
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iptables(['-N', 'reaction']),
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// Set its default to ACCEPT
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iptables(['-A', 'reaction', '-j', 'ACCEPT']),
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// Always accept 127.0.0.1
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iptables(['-I', 'reaction', '1', '-s', '127.0.0.1', '-j', 'ACCEPT']),
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// Always accept ::1
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iptables(['-I', 'reaction', '1', '-s', '::1', '-j', 'ACCEPT']),
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// Insert this chain as the first item of the INPUT chain (for incoming connections)
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iptables(['-I', 'INPUT', '-p', 'all', '-j', 'reaction']),
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],
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// Those commands will be executed in order at stop, after everything else
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stop: [
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// Remove the chain from the INPUT chain
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iptables(['-D,', 'INPUT', '-p', 'all', '-j', 'reaction']),
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// Empty the chain
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iptables(['-F,', 'reaction']),
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// Delete the chain
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iptables(['-X,', 'reaction']),
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],
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// streams are commands
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// they're run and their ouptut is captured
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// *example:* `tail -f /var/log/nginx/access.log`
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// their output will be used by one or more filters
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streams: {
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// streams have a user-defined name
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ssh: {
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// note that if the command is not in environment's `PATH`
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// its full path must be given.
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cmd: ['journalctl', '-n0', '-fu', 'sshd.service'],
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// filters run actions when they match regexes on a stream
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filters: {
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// filters have a user-defined name
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failedlogin: {
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// reaction's regex syntax is defined here: https://github.com/google/re2/wiki/Syntax
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regex: [
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// <ip> is predefined in the patterns section
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// ip's regex is inserted in the following regex
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'authentication failure;.*rhost=<ip>',
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],
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// if retry and retryperiod are defined,
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// the actions will only take place if a same pattern is
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// found `retry` times in a `retryperiod` interval
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retry: 3,
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// format is defined here: https://pkg.go.dev/time#ParseDuration
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retryperiod: '6h',
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// actions are run by the filter when regexes are matched
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actions: {
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// actions have a user-defined name
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ban: {
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// JSONNET substitutes the variable (defined at the beginning of the file)
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cmd: iptablesban,
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},
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unban: {
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cmd: iptablesunban,
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// if after is defined, the action will not take place immediately, but after a specified duration
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// same format as retryperiod
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after: '48h',
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// let's say reaction is quitting. does it run all those pending commands which had an `after` duration set?
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// if you want reaction to run those pending commands before exiting, you can set this:
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onexit: true,
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// (defaults to false)
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// here it is not useful because we will flush the chain containing the bans anyway
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// (see /conf/reaction.service)
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},
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},
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},
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},
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},
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},
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}
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// persistence
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// tldr; when an `after` action is set in a filter, such filter acts as a 'jail',
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// which is persisted after reboots.
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// full;
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// when a filter is triggered, there are 2 flows:
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//
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// if none of its actions have an `after` directive set:
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// no action will be replayed.
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//
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// else (if at least one action has an `after` directive set):
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// if reaction stops while `after` actions are pending:
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// and reaction starts again while those actions would still be pending:
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// reaction executes the past actions (actions without after or with then+after < now)
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// and plans the execution of future actions (actions with then+after > now)
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