559 lines
22 KiB
Scheme
559 lines
22 KiB
Scheme
;;; GNU Guix --- Functional package management for GNU
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;;; Copyright © 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
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;;; Copyright © 2016 David Craven <david@craven.ch>
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;;; Copyright © 2016 Julien Lepiller <julien@lepiller.eu>
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;;; Copyright © 2017 Clément Lassieur <clement@lassieur.org>
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;;;
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;;; This file is part of GNU Guix.
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;;;
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;;; GNU Guix is free software; you can redistribute it and/or modify it
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;;; under the terms of the GNU General Public License as published by
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;;; the Free Software Foundation; either version 3 of the License, or (at
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;;; your option) any later version.
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;;;
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;;; GNU Guix is distributed in the hope that it will be useful, but
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;;; WITHOUT ANY WARRANTY; without even the implied warranty of
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;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;;; GNU General Public License for more details.
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;;;
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;;; You should have received a copy of the GNU General Public License
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;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
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(define-module (gnu services ssh)
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#:use-module (gnu packages ssh)
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#:use-module (gnu packages admin)
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#:use-module (gnu services)
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#:use-module (gnu services shepherd)
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#:use-module (gnu system pam)
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#:use-module (gnu system shadow)
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#:use-module (guix gexp)
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#:use-module (guix records)
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#:use-module (guix modules)
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#:use-module (srfi srfi-1)
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#:use-module (srfi srfi-26)
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#:use-module (ice-9 match)
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#:export (lsh-configuration
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lsh-configuration?
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lsh-service
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lsh-service-type
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openssh-configuration
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openssh-configuration?
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openssh-service-type
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dropbear-configuration
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dropbear-configuration?
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dropbear-service-type
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dropbear-service))
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;;; Commentary:
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;;;
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;;; This module implements secure shell (SSH) services.
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;;;
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;;; Code:
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(define-record-type* <lsh-configuration>
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lsh-configuration make-lsh-configuration
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lsh-configuration?
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(lsh lsh-configuration-lsh
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(default lsh))
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(daemonic? lsh-configuration-daemonic?)
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(host-key lsh-configuration-host-key)
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(interfaces lsh-configuration-interfaces)
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(port-number lsh-configuration-port-number)
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(allow-empty-passwords? lsh-configuration-allow-empty-passwords?)
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(root-login? lsh-configuration-root-login?)
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(syslog-output? lsh-configuration-syslog-output?)
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(pid-file? lsh-configuration-pid-file?)
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(pid-file lsh-configuration-pid-file)
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(x11-forwarding? lsh-configuration-x11-forwarding?)
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(tcp/ip-forwarding? lsh-configuration-tcp/ip-forwarding?)
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(password-authentication? lsh-configuration-password-authentication?)
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(public-key-authentication? lsh-configuration-public-key-authentication?)
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(initialize? lsh-configuration-initialize?))
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(define %yarrow-seed
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"/var/spool/lsh/yarrow-seed-file")
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(define (lsh-initialization lsh host-key)
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"Return the gexp to initialize the LSH service for HOST-KEY."
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#~(begin
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(unless (file-exists? #$%yarrow-seed)
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(system* (string-append #$lsh "/bin/lsh-make-seed")
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"--sloppy" "-o" #$%yarrow-seed))
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(unless (file-exists? #$host-key)
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(mkdir-p (dirname #$host-key))
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(format #t "creating SSH host key '~a'...~%" #$host-key)
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;; FIXME: We're just doing a simple pipeline, but 'system' cannot be
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;; used yet because /bin/sh might be dangling; factorize this somehow.
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(let* ((in+out (pipe))
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(keygen (primitive-fork)))
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(case keygen
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((0)
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(close-port (car in+out))
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(close-fdes 1)
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(dup2 (fileno (cdr in+out)) 1)
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(execl (string-append #$lsh "/bin/lsh-keygen")
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"lsh-keygen" "--server"))
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(else
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(let ((write-key (primitive-fork)))
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(case write-key
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((0)
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(close-port (cdr in+out))
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(close-fdes 0)
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(dup2 (fileno (car in+out)) 0)
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(execl (string-append #$lsh "/bin/lsh-writekey")
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"lsh-writekey" "--server" "-o" #$host-key))
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(else
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(close-port (car in+out))
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(close-port (cdr in+out))
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(waitpid keygen)
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(waitpid write-key))))))))))
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(define (lsh-activation config)
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"Return the activation gexp for CONFIG."
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#~(begin
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(use-modules (guix build utils))
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(mkdir-p "/var/spool/lsh")
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#$(if (lsh-configuration-initialize? config)
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(lsh-initialization (lsh-configuration-lsh config)
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(lsh-configuration-host-key config))
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#t)))
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(define (lsh-shepherd-service config)
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"Return a <shepherd-service> for lsh with CONFIG."
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(define lsh (lsh-configuration-lsh config))
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(define pid-file (lsh-configuration-pid-file config))
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(define pid-file? (lsh-configuration-pid-file? config))
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(define daemonic? (lsh-configuration-daemonic? config))
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(define interfaces (lsh-configuration-interfaces config))
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(define lsh-command
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(append
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(cons (file-append lsh "/sbin/lshd")
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(if daemonic?
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(let ((syslog (if (lsh-configuration-syslog-output? config)
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'()
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(list "--no-syslog"))))
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(cons "--daemonic"
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(if pid-file?
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(cons #~(string-append "--pid-file=" #$pid-file)
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syslog)
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(cons "--no-pid-file" syslog))))
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(if pid-file?
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(list #~(string-append "--pid-file=" #$pid-file))
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'())))
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(cons* #~(string-append "--host-key="
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#$(lsh-configuration-host-key config))
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#~(string-append "--password-helper=" #$lsh "/sbin/lsh-pam-checkpw")
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#~(string-append "--subsystems=sftp=" #$lsh "/sbin/sftp-server")
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"-p" (number->string (lsh-configuration-port-number config))
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(if (lsh-configuration-password-authentication? config)
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"--password" "--no-password")
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(if (lsh-configuration-public-key-authentication? config)
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"--publickey" "--no-publickey")
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(if (lsh-configuration-root-login? config)
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"--root-login" "--no-root-login")
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(if (lsh-configuration-x11-forwarding? config)
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"--x11-forward" "--no-x11-forward")
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(if (lsh-configuration-tcp/ip-forwarding? config)
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"--tcpip-forward" "--no-tcpip-forward")
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(if (null? interfaces)
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'()
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(map (cut string-append "--interface=" <>)
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interfaces)))))
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(define requires
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(if (and daemonic? (lsh-configuration-syslog-output? config))
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'(networking syslogd)
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'(networking)))
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(list (shepherd-service
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(documentation "GNU lsh SSH server")
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(provision '(ssh-daemon))
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(requirement requires)
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(start #~(make-forkexec-constructor (list #$@lsh-command)))
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(stop #~(make-kill-destructor)))))
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(define (lsh-pam-services config)
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"Return a list of <pam-services> for lshd with CONFIG."
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(list (unix-pam-service
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"lshd"
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#:allow-empty-passwords?
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(lsh-configuration-allow-empty-passwords? config))))
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(define lsh-service-type
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(service-type (name 'lsh)
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(extensions
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(list (service-extension shepherd-root-service-type
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lsh-shepherd-service)
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(service-extension pam-root-service-type
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lsh-pam-services)
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(service-extension activation-service-type
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lsh-activation)))))
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(define* (lsh-service #:key
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(lsh lsh)
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(daemonic? #t)
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(host-key "/etc/lsh/host-key")
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(interfaces '())
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(port-number 22)
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(allow-empty-passwords? #f)
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(root-login? #f)
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(syslog-output? #t)
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(pid-file? #f)
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(pid-file "/var/run/lshd.pid")
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(x11-forwarding? #t)
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(tcp/ip-forwarding? #t)
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(password-authentication? #t)
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(public-key-authentication? #t)
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(initialize? #t))
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"Run the @command{lshd} program from @var{lsh} to listen on port @var{port-number}.
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@var{host-key} must designate a file containing the host key, and readable
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only by root.
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When @var{daemonic?} is true, @command{lshd} will detach from the
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controlling terminal and log its output to syslogd, unless one sets
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@var{syslog-output?} to false. Obviously, it also makes lsh-service
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depend on existence of syslogd service. When @var{pid-file?} is true,
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@command{lshd} writes its PID to the file called @var{pid-file}.
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When @var{initialize?} is true, automatically create the seed and host key
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upon service activation if they do not exist yet. This may take long and
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require interaction.
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When @var{initialize?} is false, it is up to the user to initialize the
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randomness generator (@pxref{lsh-make-seed,,, lsh, LSH Manual}), and to create
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a key pair with the private key stored in file @var{host-key} (@pxref{lshd
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basics,,, lsh, LSH Manual}).
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When @var{interfaces} is empty, lshd listens for connections on all the
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network interfaces; otherwise, @var{interfaces} must be a list of host names
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or addresses.
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@var{allow-empty-passwords?} specifies whether to accept log-ins with empty
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passwords, and @var{root-login?} specifies whether to accept log-ins as
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root.
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The other options should be self-descriptive."
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(service lsh-service-type
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(lsh-configuration (lsh lsh) (daemonic? daemonic?)
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(host-key host-key) (interfaces interfaces)
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(port-number port-number)
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(allow-empty-passwords? allow-empty-passwords?)
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(root-login? root-login?)
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(syslog-output? syslog-output?)
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(pid-file? pid-file?) (pid-file pid-file)
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(x11-forwarding? x11-forwarding?)
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(tcp/ip-forwarding? tcp/ip-forwarding?)
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(password-authentication?
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password-authentication?)
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(public-key-authentication?
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public-key-authentication?)
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(initialize? initialize?))))
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;;;
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;;; OpenSSH.
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;;;
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(define-record-type* <openssh-configuration>
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openssh-configuration make-openssh-configuration
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openssh-configuration?
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;; <package>
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(openssh openssh-configuration-openssh
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(default openssh))
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;; string
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(pid-file openssh-configuration-pid-file
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(default "/var/run/sshd.pid"))
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;; integer
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(port-number openssh-configuration-port-number
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(default 22))
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;; Boolean | 'without-password
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(permit-root-login openssh-configuration-permit-root-login
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(default #f))
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;; Boolean
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(allow-empty-passwords? openssh-configuration-allow-empty-passwords?
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(default #f))
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;; Boolean
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(password-authentication? openssh-configuration-password-authentication?
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(default #t))
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;; Boolean
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(public-key-authentication? openssh-configuration-public-key-authentication?
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(default #t))
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;; Boolean
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(x11-forwarding? openssh-configuration-x11-forwarding?
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(default #f))
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;; Boolean
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(challenge-response-authentication? openssh-challenge-response-authentication?
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(default #f))
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;; Boolean
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(use-pam? openssh-configuration-use-pam?
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(default #t))
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;; Boolean
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(print-last-log? openssh-configuration-print-last-log?
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(default #t))
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;; list of two-element lists
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(subsystems openssh-configuration-subsystems
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(default '(("sftp" "internal-sftp"))))
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;; list of user-name/file-like tuples
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(authorized-keys openssh-authorized-keys
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(default '())))
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(define %openssh-accounts
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(list (user-group (name "sshd") (system? #t))
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(user-account
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(name "sshd")
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(group "sshd")
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(system? #t)
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(comment "sshd privilege separation user")
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(home-directory "/var/run/sshd")
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(shell #~(string-append #$shadow "/sbin/nologin")))))
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(define (openssh-activation config)
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"Return the activation GEXP for CONFIG."
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(with-imported-modules '((guix build utils))
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#~(begin
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(use-modules (guix build utils))
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(define (touch file-name)
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(call-with-output-file file-name (const #t)))
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;; Make sure /etc/ssh can be read by the 'sshd' user.
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(mkdir-p "/etc/ssh")
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(chmod "/etc/ssh" #o755)
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(mkdir-p (dirname #$(openssh-configuration-pid-file config)))
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;; 'sshd' complains if the authorized-key directory and its parents
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;; are group-writable, which rules out /gnu/store. Thus we copy the
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;; authorized-key directory to /etc.
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(catch 'system-error
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(lambda ()
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(delete-file-recursively "/etc/authorized_keys.d"))
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(lambda args
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(unless (= ENOENT (system-error-errno args))
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(apply throw args))))
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(copy-recursively #$(authorized-key-directory
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(openssh-authorized-keys config))
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"/etc/ssh/authorized_keys.d")
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(chmod "/etc/ssh/authorized_keys.d" #o555)
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(let ((lastlog "/var/log/lastlog"))
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(when #$(openssh-configuration-print-last-log? config)
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(unless (file-exists? lastlog)
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(touch lastlog))))
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;; Generate missing host keys.
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(system* (string-append #$(openssh-configuration-openssh config)
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"/bin/ssh-keygen") "-A"))))
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(define (authorized-key-directory keys)
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"Return a directory containing the authorized keys specified in KEYS, a list
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of user-name/file-like tuples."
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(define build
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(with-imported-modules (source-module-closure '((guix build utils)))
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#~(begin
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(use-modules (ice-9 match) (srfi srfi-26)
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(guix build utils))
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(mkdir #$output)
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(for-each (match-lambda
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((user keys ...)
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(let ((file (string-append #$output "/" user)))
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(call-with-output-file file
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(lambda (port)
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(for-each (lambda (key)
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(call-with-input-file key
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(cut dump-port <> port)))
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keys))))))
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'#$keys))))
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(computed-file "openssh-authorized-keys" build))
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(define (openssh-config-file config)
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"Return the sshd configuration file corresponding to CONFIG."
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(computed-file
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"sshd_config"
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#~(begin
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(use-modules (ice-9 match))
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(call-with-output-file #$output
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(lambda (port)
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(display "# Generated by 'openssh-service'.\n" port)
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(format port "Port ~a\n"
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#$(number->string
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(openssh-configuration-port-number config)))
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(format port "PermitRootLogin ~a\n"
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#$(match (openssh-configuration-permit-root-login config)
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(#t "yes")
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(#f "no")
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('without-password "without-password")))
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(format port "PermitEmptyPasswords ~a\n"
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#$(if (openssh-configuration-allow-empty-passwords? config)
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"yes" "no"))
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(format port "PasswordAuthentication ~a\n"
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#$(if (openssh-configuration-password-authentication? config)
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"yes" "no"))
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(format port "PubkeyAuthentication ~a\n"
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#$(if (openssh-configuration-public-key-authentication?
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config)
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"yes" "no"))
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(format port "X11Forwarding ~a\n"
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#$(if (openssh-configuration-x11-forwarding? config)
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"yes" "no"))
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(format port "PidFile ~a\n"
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#$(openssh-configuration-pid-file config))
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(format port "ChallengeResponseAuthentication ~a\n"
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#$(if (openssh-challenge-response-authentication? config)
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"yes" "no"))
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(format port "UsePAM ~a\n"
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#$(if (openssh-configuration-use-pam? config)
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"yes" "no"))
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(format port "PrintLastLog ~a\n"
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#$(if (openssh-configuration-print-last-log? config)
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"yes" "no"))
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;; Add '/etc/authorized_keys.d/%u', which we populate.
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(format port "AuthorizedKeysFile \
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.ssh/authorized_keys .ssh/authorized_keys2 /etc/ssh/authorized_keys.d/%u\n")
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(for-each
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(match-lambda
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((name command) (format port "Subsystem\t~a\t~a\n" name command)))
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'#$(openssh-configuration-subsystems config))
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#t)))))
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(define (openssh-shepherd-service config)
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"Return a <shepherd-service> for openssh with CONFIG."
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(define pid-file
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(openssh-configuration-pid-file config))
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(define openssh-command
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#~(list (string-append #$(openssh-configuration-openssh config) "/sbin/sshd")
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"-D" "-f" #$(openssh-config-file config)))
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(list (shepherd-service
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(documentation "OpenSSH server.")
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(requirement '(syslogd))
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(provision '(ssh-daemon))
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(start #~(make-forkexec-constructor #$openssh-command
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#:pid-file #$pid-file))
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(stop #~(make-kill-destructor)))))
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(define (openssh-pam-services config)
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"Return a list of <pam-services> for sshd with CONFIG."
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(list (unix-pam-service
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"sshd"
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#:allow-empty-passwords?
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(openssh-configuration-allow-empty-passwords? config))))
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(define (extend-openssh-authorized-keys config keys)
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"Extend CONFIG with the extra authorized keys listed in KEYS."
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(openssh-configuration
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(inherit config)
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(authorized-keys
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(append (openssh-authorized-keys config) keys))))
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(define openssh-service-type
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(service-type (name 'openssh)
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(extensions
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(list (service-extension shepherd-root-service-type
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openssh-shepherd-service)
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(service-extension pam-root-service-type
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openssh-pam-services)
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(service-extension activation-service-type
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openssh-activation)
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(service-extension account-service-type
|
||
(const %openssh-accounts))))
|
||
(compose concatenate)
|
||
(extend extend-openssh-authorized-keys)
|
||
(default-value (openssh-configuration))))
|
||
|
||
|
||
;;;
|
||
;;; Dropbear.
|
||
;;;
|
||
|
||
(define-record-type* <dropbear-configuration>
|
||
dropbear-configuration make-dropbear-configuration
|
||
dropbear-configuration?
|
||
(dropbear dropbear-configuration-dropbear
|
||
(default dropbear))
|
||
(port-number dropbear-configuration-port-number
|
||
(default 22))
|
||
(syslog-output? dropbear-configuration-syslog-output?
|
||
(default #t))
|
||
(pid-file dropbear-configuration-pid-file
|
||
(default "/var/run/dropbear.pid"))
|
||
(root-login? dropbear-configuration-root-login?
|
||
(default #f))
|
||
(allow-empty-passwords? dropbear-configuration-allow-empty-passwords?
|
||
(default #f))
|
||
(password-authentication? dropbear-configuration-password-authentication?
|
||
(default #t)))
|
||
|
||
(define (dropbear-activation config)
|
||
"Return the activation gexp for CONFIG."
|
||
#~(begin
|
||
(use-modules (guix build utils))
|
||
(mkdir-p "/etc/dropbear")))
|
||
|
||
(define (dropbear-shepherd-service config)
|
||
"Return a <shepherd-service> for dropbear with CONFIG."
|
||
(define dropbear
|
||
(dropbear-configuration-dropbear config))
|
||
|
||
(define pid-file
|
||
(dropbear-configuration-pid-file config))
|
||
|
||
(define dropbear-command
|
||
#~(list (string-append #$dropbear "/sbin/dropbear")
|
||
|
||
;; '-R' allows host keys to be automatically generated upon first
|
||
;; connection, at a time when /dev/urandom is more likely securely
|
||
;; seeded.
|
||
"-F" "-R"
|
||
|
||
"-p" #$(number->string (dropbear-configuration-port-number config))
|
||
"-P" #$pid-file
|
||
#$@(if (dropbear-configuration-syslog-output? config) '() '("-E"))
|
||
#$@(if (dropbear-configuration-root-login? config) '() '("-w"))
|
||
#$@(if (dropbear-configuration-password-authentication? config)
|
||
'()
|
||
'("-s" "-g"))
|
||
#$@(if (dropbear-configuration-allow-empty-passwords? config)
|
||
'("-B")
|
||
'())))
|
||
|
||
(define requires
|
||
(if (dropbear-configuration-syslog-output? config)
|
||
'(networking syslogd) '(networking)))
|
||
|
||
(list (shepherd-service
|
||
(documentation "Dropbear SSH server.")
|
||
(requirement requires)
|
||
(provision '(ssh-daemon))
|
||
(start #~(make-forkexec-constructor #$dropbear-command
|
||
#:pid-file #$pid-file))
|
||
(stop #~(make-kill-destructor)))))
|
||
|
||
(define dropbear-service-type
|
||
(service-type (name 'dropbear)
|
||
(extensions
|
||
(list (service-extension shepherd-root-service-type
|
||
dropbear-shepherd-service)
|
||
(service-extension activation-service-type
|
||
dropbear-activation)))))
|
||
|
||
(define* (dropbear-service #:optional (config (dropbear-configuration)))
|
||
"Run the @uref{https://matt.ucc.asn.au/dropbear/dropbear.html,Dropbear SSH
|
||
daemon} with the given @var{config}, a @code{<dropbear-configuration>}
|
||
object."
|
||
(service dropbear-service-type config))
|
||
|
||
;;; ssh.scm ends here
|