init

.gitignore

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+# ---> Vim
+# Swap
+[._]*.s[a-v][a-z]
+!*.svg  # comment out if you don't need vector files
+[._]*.sw[a-p]
+[._]s[a-rt-v][a-z]
+[._]ss[a-gi-z]
+[._]sw[a-p]
+
+# Session
+Session.vim
+Sessionx.vim
+
+# Temporary
+.netrwhist
+*~
+# Auto-generated tag files
+tags
+# Persistent undo
+[._]*.un~
+
+# ---> Ansible
+*.retry
+

README.adoc

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+Role Name
+=========
+
+A brief description of the role goes here.
+
+Requirements
+------------
+
+Any pre-requisites that may not be covered by Ansible itself or the role should be mentioned here. For instance, if the role uses the EC2 module, it may be a good idea to mention in this section that the boto package is required.
+
+Role Variables
+--------------
+
+ssh_ca_name::
+Name for your CA - will be stored as comment.
+If CA already exists, it will not be changed.
+Mandatory.
+
+ssh_ca_user::
+User for CA.
+Must match with `ssh_cert`-role.
+Default: `sshca`
+
+ssh_ca_home::
+Default: `/var/lib/sshca`
+
+ssh_ca_base_dir::
+Where to store the certs and CA.
+Must match with `ssh_cert`-role.
+Default: `~/.ssh-ca`
+**Do not change!**
+
+ssh_ca_force_regeneration::
+Forces to regenerate the CA.
+*The old will be deleted!**
+
+Dependencies
+------------
+
+Use ssh-cert to use ssh-ca-server for re-/newal hosts and users certificates.
+
+Example Playbook
+----------------
+
+.example playbook
+----
+- name: SSH-CA
+  hosts: ssh_ca_server
+	roles:
+	- role: ssh-ca
+----
+
+License
+-------
+
+AGPLv3
+
+Author Information
+------------------
+
+Denis Knauf - https://git.denkn.at/deac/ansible-role-ssh-cert

defaults/main.yml

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+---
+# defaults file for ssh-ca

files/ssh-ca.rb

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+#!/usr/bin/env ruby
+
+require 'time'
+require 'pathname'
+require 'shellwords'
+require 'getoptlong'
+require 'active_support/time'
+require 'json'
+
+def help msg=nil
+	STDERR.puts msg  if msg
+	STDERR.puts <<-EOHELP.gsub( /^\s*:/, '')
+		:Usage: ssh .... renew [force] [show]
+		:       ssh .... show
+		:       ssh .... help
+		:       ssh .... jsonl
+		:
+		:[h]elp
+		:[r]enew     Renews (if expires in graceperiod) or creates (if not existing) certificate
+		: [f]orce    forces renewal, also if valid for graceperiod
+		:[s]how      Shows current certificate
+		:jsonl       Expect commands via STDIN as JSONL and responses via STDOUT in JSONL
+		:             Request format: [0, CMD, ARGS...]
+		:             Response format: [SCODE, BODY]
+		:             SCODEs are like HTTP.
+		:
+		:possible CMD:
+		:<renew[, {<force: true|false>}]> => <RENEWED, DATA, CONTENT>
+		:<get>                            => <DATA, CONTENT>
+		:
+		:  RENEWED indicates if file was renewed (true|false).
+		:  CONTENT is the content of the certfile (String).
+		:  DATA is the parsed file (ssh-keygen -L) (Hash).
+		EOHELP
+	exit 1
+end
+
+class Die <Exception
+end
+
+module Kernel
+	def popen *a, **o, &e
+		a = a.flatten.compact.map &:to_s
+		IO.popen a, **o, &e
+	end
+
+	def die str
+		raise Die, str
+	end
+end
+
+module FileHelper
+	attr_reader :file
+
+	def exist?
+		@file.file?
+	end
+
+	def read
+		@file.read
+	end
+
+	def open *a, **o, &e
+		if block_given?
+			@file.open *a, **o, &e
+		else
+			@file.open *a, **o
+		end
+	end
+
+	def to_s
+		@file.to_s
+	end
+end
+
+class PublicKeyFile
+	include FileHelper
+	attr_reader :type, :ident
+
+	def initialize file, type, ident
+		@file, @type, @ident = file, type, ident
+	end
+
+	def prepare authkeysfile
+		return true  if exist?
+		authkeysfile.each_line do |l|
+			case l.chomp
+			when /\A\s*#/ # ignore - comment
+			when /\A\s*$/ # ignore - empty line
+			when /\Assh-/ # ignore - blank keys without command
+			when / (ssh-(?:rsa|ed25519) +[^ ]+ +#{Regexp.quote @ident}) *\z/
+				pub = $1
+				@file.open( 'a+') {|f| f.puts pub }
+			end
+		end
+		exist?
+	end
+end
+
+class CertifcateFile
+	include FileHelper
+	attr_reader :metadata
+
+	def initialize file
+		@file = file
+	end
+
+	def parse
+		r = {}
+		popen %w[ssh-keygen -L -f], @file do |f|
+			mode = nil
+			f.each_line do |l|
+				case l.chomp
+				when /^        Valid: from ([^ ][^ ]*) to ([^ ][^ ]*)$/
+					r[:valid] = Time.parse( $1) ... Time.parse( $2)
+				when /^        Type: ([^ ]+) ([^ ]+) certificate$/
+					r[:type]  = [$1, $2]
+				when /^        Public key: ([^ ]+) (.*)$/
+					r[:pubkey]= [$1, $2]
+				when /^        Signing CA: ([^ ]+) (.*)$/
+					r[:signca]= [$1, $2]
+				when /^        Key ID: (.*)$/
+					r[:keyid] = $1.sub /\A"?(.*?)"?\z/, '\1'
+				when /^        Serial: (\d+)$/
+					r[:serial]= $1.to_i
+				when /^        Principals: \(node\)$/
+					r[:principals] = []
+				when /^        Principals:\s*$/
+					mode = :principals
+					r[:principals] = []
+				when /^        Extensions: \(none\)$/
+					r[:extensions] = []
+				when /^        Extensions:\s*$/
+					mode = :extensions
+					r[:extensions] = []
+				when /^        Critical Options: \(none\)$/
+					r[:critopts] = []
+				when /^        Critical Options:\s*$/
+					mode = :critopts
+					r[:critopts] = []
+				when /^                ([^ ].*)$/
+					r[mode].push $1
+				else
+				end
+			end
+		end
+		@metadata = r
+	end
+
+	def [] key
+		(@metadata || parse)[key]
+	end
+	alias to_hash []
+
+	def valid_at? ts
+		exist? and self[:valid].include?( ts)
+	end
+
+	def create pubfile, type:, valid:, serial:, cafile:, info:, principals:, sshcadir:
+		#sign_user_pub opts
+		err =
+			popen( %w[ssh-keygen -V], "#{valid.begin.strftime '%Y%m%d'}:#{valid.end.strftime '%Y%m%d'}",
+						(:host == type ? '-h' : nil), '-s', cafile,
+						'-P', '', '-z', serial, '-I', info, '-n', principals.join(','), pubfile,
+					err: %i[child out]
+				) {|l| l.read }
+		die "Creating certificate failed [#{$?.inspect}]: #{err}"  unless 0 == $?.exitstatus
+		serialkeyfile = sshcadir + 'serials' + serial.to_s
+		serialkeyfile.open( 'a+') {|f| f.write self.read }
+		self
+	end
+end
+
+class SerialFile
+	include FileHelper
+
+	def initialize file
+		@file = file
+	end
+
+	def read
+		open 'a+' do |fh|
+			fh.read.to_i
+		end
+	end
+	alias to_i read
+	alias get read
+
+	def increment!
+		open 'a+' do |fh|
+			(1+fh.read.to_i).tap do |val|
+				fh.rewind
+				fh.truncate 0
+				fh.print val
+			end
+		end
+	end
+	alias inc! increment!
+end
+
+
+#################################################
+begin
+
+die "2..4 arguments (type ident [principals [info]]) expected.  Provided count of arguments: #{ARGV.length}"  unless (2..4) === ARGV.length
+type, ident, principals, info = ARGV[0..3]
+expire_in, gracetime = 12.weeks, 1.week
+type = type.to_sym
+case type
+when :host
+	die "Invalid ident: #{ident}"  unless ident =~ /\A[a-z][a-z_0-9]*\z/i
+	expire_in, gracetime = 360.days, 30.days
+	info ||= "host: #{ident}"
+	principals =
+		([ident] +
+			principals.split( ',').map do |e|
+				if /:/ =~ e or /\A[0-9.]+\z/ =~ e or /\A[^.]+\z/ =~ e
+					e
+				else
+					e = e.gsub /\.?\z/, ''
+					[e, "#{e}."]
+				end
+			end
+		).flatten.compact.map do |e|
+			if /\A\[/ =~ e
+				e
+			else
+				[e, "[#{e}]:19"]
+			end
+		end.flatten.compact.uniq
+when :user
+	die "Invalid ident: #{ident}"  unless ident =~ /\A[a-z][a-z_0-9]*@[a-z][a-z_0-9]*\z/i
+	info ||= "user: #{ident}"
+	principals = principals.split ','
+else
+	die "Invalid type: #{type}"
+end
+
+sshcadir     = Pathname.new( "~/.ssh-ca").expand_path
+pubfile      = PublicKeyFile.new sshcadir + "#{type}-#{ident}.pub", type, ident
+certfile     = CertifcateFile.new sshcadir + "#{type}-#{ident}-cert.pub"
+cafile       = sshcadir + "ca"
+capubfile    = sshcadir + "ca.pub"
+serialfile   = SerialFile.new sshcadir + "serial"
+authkeysfile = Pathname.new( "~/.ssh/authorized_keys").expand_path
+
+help  unless ENV['SSH_ORIGINAL_COMMAND']
+die "Unallowed char in arguments [\\0]"  if ENV['SSH_ORIGINAL_COMMAND'].include? 0.chr
+ARGV.replace ENV['SSH_ORIGINAL_COMMAND'].shellsplit
+case ARGV[0]
+when *%w[h help]
+	help
+
+when *%w[s show]
+	die "Unexpected addition parameters: #{ARGV.shelljoin}"  unless 1 == ARGV.length
+	die "No certfile, yet: #{certfile.basename}"  unless certfile.exist?
+	puts certfile.read
+
+when *%w[r renew]
+	begin
+		unexpected = ARGV[1..-1] - %w[s show f force]
+		die "Unknown argument: #{unexpected.shelljoin}"  unless unexpected.empty?
+	end
+	show  = ! (ARGV[1..-1] & %w[s show]).empty?
+	force = ! (ARGV[1..-1] & %w[f force]).empty?
+
+	pubfile.prepare authkeysfile
+	die "Pubfile or pub in authorized_keys for #{ident} not found."  unless pubfile.exist?
+
+	if !force && certfile.exist? && certfile.valid_at?( gracetime.from_now) && certfile[:principals].sort == principals.sort
+		STDERR.print "Certificate [#{certfile[:serial]}|#{certfile[:keyid]}] valid between #{certfile[:valid]} as #{certfile[:principals].sort.join ', '}\n"
+		STDERR.flush
+		STDOUT.print "#{certfile.read.chomp}\n"  if show
+		exit 0
+	end
+
+	STDERR.puts "Renew certificate for #{ident} as #{principals.sort.join ', '}"
+	certfile.create pubfile, type: type, valid: -5.minutes.ago..expire_in.from_now,
+		serial: serialfile.increment!, cafile: cafile, info: info, principals: principals, sshcadir: sshcadir
+	puts certfile.read  if show
+
+when 'jsonl'
+	STDIN.each_line do |line|
+		begin
+			line = JSON.parse line, symbolize_names: true
+			cmd, args  = line[0].to_sym, line[1..-1]
+			case cmd
+			when :renew
+				die "renew expects no or a Hash as args."  unless (0..1).include?( args.length) && args.kind_of?( Hash)
+				args ||= {}
+				args[:force] = ! ! args[:force]
+
+				pubfile.prepare
+				die "Pubfile or pub in authorized_keys for #{ident} not found."  unless pubfile.exist?
+
+				if !args[:force] && certfile.valid_at?( gracetime.from_now)
+					STDOUT.puts [200, false, certfile.metadata, certfile.read].to_json
+				end
+
+				certfile.create pubfile, type: type, sshcadir: sshcadir,
+					valid: -5.minutes.ago..expire_in.from_now, serial: serialfile.increment!,
+					cafile: cafile, info: info, principals: principals
+				STDOUT.puts [200, true, certfile.metadata, certfile.read].to_json
+
+			when :get
+				STDOUT.puts [200, certfile.metadata, certfile.read].to_json
+
+			else
+				die "Unknown command."
+			end
+		rescue Object
+			STDOUT.puts [500, $!.class.name, $!.to_s].to_json
+		end
+	end
+
+else
+	help "Unknown command: #{ARGV[0]}"
+end
+
+rescue SystemExit
+	raise
+rescue Die
+	STDERR.puts $!
+	exit 1
+rescue Object
+	STDERR.puts "#$! (#{$!.class})", *$!.backtrace
+	exit 2
+end

handlers/main.yml

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+---
+# handlers file for ssh-ca

meta/main.yml

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+galaxy_info:
+  author: Denis Knauf
+  description: Provides a SSH-CA renewal server
+
+  # issue_tracker_url: http://example.com/issue/tracker
+  license: AGPL-3.0-or-later
+
+  min_ansible_version: 2.9
+
+  # If this a Container Enabled role, provide the minimum Ansible Container version.
+  # min_ansible_container_version:
+
+  platforms:
+  - name: Debian
+    versions:
+    - 10
+  - name: Ubuntu
+    versions:
+    - 18.04
+    - 20.04
+
+  galaxy_tags: []
+    # List tags for your role here, one per line. A tag is a keyword that describes
+    # and categorizes the role. Users find roles by searching for tags. Be sure to
+    # remove the '[]' above, if you add tags to this list.
+    #
+    # NOTE: A tag is limited to a single word comprised of alphanumeric characters.
+    #       Maximum 20 tags per role.
+
+dependencies: []
+  # List your role dependencies here, one per line. Be sure to remove the '[]' above,
+  # if you add dependencies to this list.

tasks/main.yml

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+---
+# vim: set expandtab tabstop=2 shiftwidth=2:
+- name: create sshca-user
+  user:
+    name: '{{ssh_ca_user}}'
+    comment: SSH-CA
+    shell: /bin/sh
+    createhome: yes
+    home: '{{ssh_ca_home}}'
+    move_home: no
+    skeleton: no
+- name: install ssh-ca
+  copy:
+    src: ssh-ca.rb
+    dest: '{{ssh_ca_home}}/ssh-ca'
+- name: base-dir
+  file:
+    path: '{{ssh_ca_base_dir}}'
+    owner: '{{ssh_ca_user}}'
+    mode: 0700
+- name: CA
+  openssh_keypair:
+    path: '{{ssh_ca_base_dir}}/ca'
+    type: ed25519
+    owner: '{{ssh_ca_user}}'
+    comment: '{{ssh_ca_name|mandatory}}'
+    force: '{{ssh_ca_force_regeneration|default(false)}}'

tests/inventory

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+localhost
+

tests/test.yml

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+---
+# vim: set et sw=2 ts=2 sts=2:
+- hosts: localhost
+  remote_user: root
+  roles:
+  - ssh-ca

vars/main.yml

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+---
+# vim: set et sw=2 ts=2 sws=2:
+ssh_ca_user:              sshca
+ssh_ca_home:              /var/lib/sshca
+ssh_ca_base_dir:          ~/.ssh-ca