;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2022 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2023 Janneke Nieuwenhuizen <janneke@gnu.org>
;;; Copyright © 2023 Nicolas Graves <ngraves@ngraves.fr>
;;; Copyright © 2023 Efraim Flashner <efraim@flashner.co.il>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
(define-module (gnu home services ssh)
#:use-module (guix gexp)
#:use-module (guix records)
#:use-module (guix deprecation)
#:use-module (guix diagnostics)
#:use-module (guix i18n)
#:use-module ((guix utils) #:select (%current-system))
#:use-module (gnu services)
#:use-module (gnu services configuration)
#:use-module (guix modules)
#:use-module (gnu home services)
#:use-module (gnu home services shepherd)
#:use-module ((gnu home services utils)
#:select (object->camel-case-string))
#:autoload (gnu packages base) (libc-utf8-locales-for-target)
#:use-module (gnu packages ssh)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-9)
#:use-module (srfi srfi-9 gnu)
#:use-module (srfi srfi-34)
#:use-module (srfi srfi-35)
#:use-module (ice-9 match)
#:autoload (ice-9 regex) (string-match match:substring)
#:export (home-openssh-configuration
home-openssh-configuration-authorized-keys
home-openssh-configuration-known-hosts
home-openssh-configuration-hosts
home-openssh-configuration-add-keys-to-agent
home-openssh-configuration?
home-ssh-agent-configuration
home-ssh-agent-openssh
home-ssh-agent-socket-directory
home-ssh-agent-extra-options
home-ssh-agent-configuration?
openssh-host
openssh-host-host-name
openssh-host-match-criteria
openssh-host-identity-file
openssh-host-name
openssh-host-port
openssh-host-user
openssh-host-forward-x11?
openssh-host-forward-x11-trusted?
openssh-host-forward-agent?
openssh-host-compression?
openssh-host-proxy-command
openssh-host-host-key-algorithms
openssh-host-accepted-key-types
openssh-host-extra-content
proxy-jump
proxy-jump-host-name
proxy-jump-port
proxy-jump-user
proxy-command
proxy-command->string
home-openssh-service-type
home-ssh-agent-service-type))
(define (serialize-field-name name)
(match name
('accepted-key-types "PubkeyAcceptedKeyTypes")
(_
(let ((name (let ((str (symbol->string name)))
(if (string-suffix? "?" str)
(string->symbol (string-drop-right str 1))
name))))
(object->camel-case-string name 'upper)))))
(define (serialize-string field value)
(string-append " " (serialize-field-name field)
" " value "\n"))
(define (address-family? obj)
(memv obj (list AF_INET AF_INET6)))
(define-maybe address-family)
(define (serialize-address-family field family)
(if (maybe-value-set? family)
(string-append " " (serialize-field-name field) " "
(cond ((= family AF_INET) "inet")
((= family AF_INET6) "inet6")
;; The 'else' branch is unreachable.
(else
(raise
(formatted-message
(G_ "~s: invalid address family value")
family))))
"\n")
""))
(define (natural-number? obj)
(and (integer? obj) (exact? obj) (> obj 0)))
(define (serialize-natural-number field value)
(string-append " " (serialize-field-name field) " "
(number->string value) "\n"))
(define-maybe boolean)
(define (serialize-boolean field value)
(string-append " " (serialize-field-name field) " "
(if value "yes" "no") "\n"))
(define-maybe string)
(define-maybe natural-number)
(define (serialize-raw-configuration-string field value)
(string-append value "\n"))
(define raw-configuration-string? string?)
(define (string-list? lst)
(and (pair? lst) (every string? lst)))
(define (serialize-string-list field lst)
(string-append " " (serialize-field-name field) " "
(string-join lst ",") "\n"))
(define-maybe string-list)
(define-record-type <proxy-command>
(proxy-command command)
proxy-command?
(command proxy-command->string))
(set-record-type-printer! <proxy-command>
(lambda (obj port)
(format port "#<proxy-command ~s>" (proxy-command->string obj))))
(define-configuration/no-serialization proxy-jump
(user
maybe-string
"User name on the remote host.")
(host-name
(string)
"Host name---e.g., @code{foo.example.org} or @code{192.168.1.2}.")
(port
maybe-natural-number
"TCP port number to connect to."))
(define (proxy-jump->string proxy-jump)
(match-record proxy-jump <proxy-jump>
(host-name user port)
(string-append
(if (maybe-value-set? user) (string-append user "@") "")
host-name
(if (maybe-value-set? port) (string-append ":" (number->string port)) ""))))
(define (proxy-command-or-jump-list? x)
(or (proxy-command? x)
(and (list? x)
(every proxy-jump? x))))
(define (serialize-proxy-command-or-jump-list field value)
(if (proxy-command? value)
(serialize-string 'proxy-command (proxy-command->string value))
(serialize-string-list 'proxy-jump (map proxy-jump->string value))))
(define-maybe proxy-command-or-jump-list)
(define (sanitize-proxy-command properties)
(lambda (value)
(when (maybe-value-set? value)
(warn-about-deprecation 'proxy-command properties #:replacement 'proxy))
(unless (maybe-string? value)
(configuration-field-error (source-properties->location properties) 'proxy-command value))
value))
(define ssh-match-keywords
'(canonical final exec host originalhost user localuser))
(define (match-criteria? str)
;; Rule out the case of "all" keyword.
(if (member str '("all"
"canonical all"
"final all"))
#t
(let* ((first (string-take str (string-index str #\ )))
(keyword (string->symbol (if (string-prefix? "!" first)
(string-drop first 1)
first))))
(memq keyword ssh-match-keywords))))
(define (serialize-match-criteria _ value)
(string-append "Match " value "\n"))
(define-maybe match-criteria)
(define-configuration openssh-host
(name
maybe-string
"Name of this host declaration. A @code{openssh-host} must define only
@code{name} or @code{match-criteria}. Use host-name @code{\"*\"} for
top-level options.")
(host-name
maybe-string
"Host name---e.g., @code{\"foo.example.org\"} or @code{\"192.168.1.2\"}.")
(match-criteria
maybe-match-criteria
"When specified, this string denotes the set of hosts to which the entry
applies, superseding the @code{host-name} field. Its first element must be
all or one of @code{ssh-match-keywords}. The rest of the elements are
arguments for the keyword, or other criteria. A @code{openssh-host} must
define only @code{name} or @code{match-criteria}. Other host configuration
options will apply to all hosts matching @code{match-criteria}.")
(address-family
maybe-address-family
"Address family to use when connecting to this host: one of
@code{AF_INET} (for IPv4 only), @code{AF_INET6} (for IPv6 only).
Additionally, the field can be left unset to allow any address family.")
(identity-file
maybe-string
"The identity file to use---e.g.,
@code{\"/home/charlie/.ssh/id_ed25519\"}.")
(port
maybe-natural-number
"TCP port number to connect to.")
(user
maybe-string
"User name on the remote host.")
(forward-x11?
maybe-boolean
"Whether to forward remote client connections to the local X11 graphical
display.")
(forward-x11-trusted?
maybe-boolean
"Whether remote X11 clients have full access to the original X11 graphical
display.")
(forward-agent?
maybe-boolean
"Whether the authentication agent (if any) is forwarded to the remote
machine.")
(compression?
maybe-boolean
"Whether to compress data in transit.")
(proxy-command
maybe-string
"The command to use to connect to the server. As an example, a command
to connect via an HTTP proxy at 192.0.2.0 would be: @code{\"nc -X
connect -x 192.0.2.0:8080 %h %p\"}. Using 'proxy-command' is deprecated, use
'proxy' instead."
(sanitizer (sanitize-proxy-command (current-source-location))))
(proxy
maybe-proxy-command-or-jump-list
"The command to use to connect to the server or a list of SSH hosts to jump
through before connecting to the server.")
(host-key-algorithms
maybe-string-list
"The list of accepted host key algorithms---e.g.,
@code{'(\"ssh-ed25519\")}.")
(accepted-key-types
maybe-string-list
"The list of accepted user public key types.")
(extra-content
(raw-configuration-string "")
"Extra content appended as-is to this @code{Host} block in
@file{~/.ssh/config}."))
(define (serialize-openssh-host config)
(define (openssh-host-name-or-match-field? field)
(or (eq? (configuration-field-name field) 'name)
(eq? (configuration-field-name field) 'match-criteria)))
(string-append
(if (maybe-value-set? (openssh-host-name config))
(if (maybe-value-set? (openssh-host-match-criteria config))
(raise
(formatted-message
(G_ "define either 'name' or 'match-criteria', not both")))
(string-append "Host " (openssh-host-name config) "\n"))
(if (maybe-value-set? (openssh-host-match-criteria config))
(serialize-match-criteria #t (openssh-host-match-criteria config))
(raise
(formatted-message
(G_ "define either 'name' or 'match-criteria' once")))))
(string-concatenate
(map (lambda (field)
((configuration-field-serializer field)
(configuration-field-name field)
((configuration-field-getter field) config)))
(remove openssh-host-name-or-match-field?
openssh-host-fields)))))
(define-record-type* <home-openssh-configuration>
home-openssh-configuration make-home-openssh-configuration
home-openssh-configuration?
(authorized-keys home-openssh-configuration-authorized-keys ;list of file-like
(default #f))
(known-hosts home-openssh-configuration-known-hosts ;unspec | list of file-like
(default *unspecified*))
(hosts home-openssh-configuration-hosts ;list of <openssh-host>
(default '()))
(add-keys-to-agent home-openssh-configuration-add-keys-to-agent ;string with limited values
(default "no")))
(define (serialize-add-keys-to-agent value)
(define (valid-time-string? str)
(and (> (string-length str) 0)
(equal?
str
(match:substring
(string-match "\
[0-9]+|([0-9]+[Ww])?([0-9]+[Dd])?([0-9]+[Hh])?([0-9]+[Mm])?([0-9]+[Ss])?"
str)))))
(string-append "AddKeysToAgent "
(cond ((member value '("yes" "no" "confirm" "ask")) value)
((valid-time-string? value) value)
((and (string-prefix? "confirm" value)
(valid-time-string?
(cdr (string-split value #\ )))) value)
;; The 'else' branch is unreachable.
(else
(raise
(formatted-message
(G_ "~s: invalid 'add-keys-to-agent' value")
value))))))
(define (openssh-configuration->string config)
(string-join
(cons* (serialize-add-keys-to-agent
(home-openssh-configuration-add-keys-to-agent config))
(map serialize-openssh-host
(home-openssh-configuration-hosts config)))
"\n"))
(define* (file-join name files #:optional (delimiter " "))
"Return a file in the store called @var{name} that is the concatenation
of all the file-like objects listed in @var{files}, with @var{delimited}
inserted after each of them."
(computed-file name
(with-imported-modules '((guix build utils))
#~(begin
(use-modules (guix build utils))
;; Support non-ASCII file names.
(setenv "GUIX_LOCPATH"
#+(file-append
(libc-utf8-locales-for-target (%current-system))
"/lib/locale"))
(setlocale LC_ALL "en_US.utf8")
(call-with-output-file #$output
(lambda (output)
(for-each (lambda (file)
(call-with-input-file file
(lambda (input)
(dump-port input output)))
(display #$delimiter output))
'#$files)))))))
(define (openssh-configuration-files config)
(let* ((ssh-config (plain-file "ssh.conf"
(openssh-configuration->string config)))
(known-hosts (home-openssh-configuration-known-hosts config))
(authorized-keys (home-openssh-configuration-authorized-keys config))
(authorized-keys (and
authorized-keys
(file-join "authorized_keys" authorized-keys "\n"))))
`(,@(if authorized-keys
`((".ssh/authorized_keys" ,authorized-keys))
'())
,@(if (unspecified? known-hosts)
'()
`((".ssh/known_hosts"
,(file-join "known_hosts" known-hosts "\n"))))
(".ssh/config" ,ssh-config))))
(define openssh-activation
(with-imported-modules (source-module-closure
'((gnu build activation)))
#~(begin
(use-modules (gnu build activation))
;; Make sure ~/.ssh is #o700.
(let* ((home (getenv "HOME"))
(dot-ssh (string-append home "/.ssh")))
(mkdir-p/perms dot-ssh (getpw (getuid)) #o700)))))
(define home-openssh-service-type
(service-type
(name 'home-openssh)
(extensions
(list (service-extension home-files-service-type
openssh-configuration-files)
(service-extension home-activation-service-type
(const openssh-activation))))
(description "Configure the OpenSSH @acronym{SSH, secure shell} client
by providing a @file{~/.ssh/config} file, which is honored by the OpenSSH
client,@command{ssh}, and by other tools such as @command{guix deploy}.")
(default-value (home-openssh-configuration))))
;;;
;;; Ssh-agent.
;;;
(define-record-type* <home-ssh-agent-configuration>
home-ssh-agent-configuration make-home-ssh-agent-configuration
home-ssh-agent-configuration?
(openssh home-ssh-agent-openssh ;file-like
(default openssh))
(socket-directory home-ssh-agent-socket-directory ;string
(default #~(string-append %user-runtime-dir "/ssh-agent")))
(extra-options home-ssh-agent-extra-options ;list of string
(default '())))
(define (home-ssh-agent-services config)
"Return a <shepherd-service> for an ssh-agent with CONFIG."
(match-record config <home-ssh-agent-configuration>
(openssh socket-directory extra-options)
(let* ((ssh-agent (file-append openssh "/bin/ssh-agent"))
(socket-file #~(string-append #$socket-directory "/socket"))
(command #~`(#$ssh-agent
"-D" "-a" ,#$socket-file
#$@extra-options))
(log-file #~(string-append %user-log-dir "/ssh-agent.log")))
(list (shepherd-service
(documentation "Run the ssh-agent.")
(provision '(ssh-agent))
(modules '((shepherd support))) ;for '%user-runtime-dir', etc.
(start #~(lambda _
(unless (file-exists? #$socket-directory)
(mkdir-p #$socket-directory)
(chmod #$socket-directory #o700))
(fork+exec-command #$command #:log-file #$log-file)))
(stop #~(make-kill-destructor)))))))
(define (home-ssh-agent-environment-variables config)
'(("SSH_AUTH_SOCK"
. "${SSH_AUTH_SOCK-${XDG_RUNTIME_DIR-$HOME/.cache}/ssh-agent/socket}")))
(define home-ssh-agent-service-type
(service-type
(name 'home-ssh-agent)
(default-value (home-ssh-agent-configuration))
(extensions
(list (service-extension home-shepherd-service-type
home-ssh-agent-services)
(service-extension home-environment-variables-service-type
home-ssh-agent-environment-variables)))
(description
"Install and configure @command{ssh-agent} as a Shepherd service.")))
