;;; GNU Guix --- Functional package management for GNU ;;; Copyright © 2022 Ludovic Courtès ;;; Copyright © 2023 Janneke Nieuwenhuizen ;;; Copyright © 2023 Nicolas Graves ;;; ;;; 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 . (define-module (gnu home services ssh) #:use-module (guix gexp) #:use-module (guix records) #:use-module (guix diagnostics) #:use-module (guix i18n) #: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) (glibc-utf8-locales) #:use-module (gnu packages ssh) #:use-module (srfi srfi-1) #:use-module (srfi srfi-34) #:use-module (srfi srfi-35) #:use-module (ice-9 match) #: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-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 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 (condition (&error))))) "\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 (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 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-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 ;TODO implement stricter match-criteria rules 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? (boolean #f) "Whether to forward remote client connections to the local X11 graphical display.") (forward-x11-trusted? (boolean #f) "Whether remote X11 clients have full access to the original X11 graphical display.") (forward-agent? (boolean #f) "Whether the authentication agent (if any) is forwarded to the remote machine.") (compression? (boolean #f) "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\"}.") (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_ "You must either define name or match-criteria, not both."))) (string-append "Host " (openssh-host-name config) "\n")) (if (maybe-value-set? (openssh-host-match-criteria config)) (string-append "Match " (string-join (openssh-host-match-criteria config) " ") "\n") (raise (formatted-message (G_ "You must either define 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 make-home-openssh-configuration home-openssh-configuration? (authorized-keys home-openssh-configuration-authorized-keys ;list of file-like (default '())) (known-hosts home-openssh-configuration-known-hosts ;unspec | list of file-like (default *unspecified*)) (hosts home-openssh-configuration-hosts ;list of (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 (is-valid-time-string? str) (and (> (string-length str) 0) (eq? (cdr (vector-ref (string-match "\ [0-9]+|([0-9]+[Ww])?([0-9]+[Dd])?([0-9]+[Hh])?([0-9]+[Mm])?([0-9]+[Ss])?" str) 1)) (string-length str)))) (string-append "AddKeysToAgent " (cond ((member value '("yes" "no" "confirm" "ask")) value) ((is-valid-time-string? value) value) ((and (string-prefix? "confirm" value) (is-valid-time-string? (cdr (string-split value #\ )))) value) ;; The 'else' branch is unreachable. (else (raise (condition (&error))))))) (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 glibc-utf8-locales "/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)) '#$files))))))) (define (openssh-configuration-files config) (let ((config (plain-file "ssh.conf" (openssh-configuration->string config))) (known-hosts (home-openssh-configuration-known-hosts config)) (authorized-keys (file-join "authorized_keys" (home-openssh-configuration-authorized-keys config) "\n"))) `((".ssh/authorized_keys" ,authorized-keys) ,@(if (unspecified? known-hosts) '() `((".ssh/known_hosts" ,(file-join "known_hosts" known-hosts "\n")))) (".ssh/config" ,config)))) (define openssh-activation (with-imported-modules (source-module-closure '((gnu build activation))) #~(begin (use-modules (gnu build activation)) ;; Make sure ~/.ssh is #o700. (let* ((home (getenv "HOME")) (dot-ssh (string-append home "/.ssh"))) (mkdir-p/perms dot-ssh (getpw (getuid)) #o700))))) (define home-openssh-service-type (service-type (name 'home-openssh) (extensions (list (service-extension home-files-service-type openssh-configuration-files) (service-extension home-activation-service-type (const openssh-activation)))) (description "Configure the OpenSSH @acronym{SSH, secure shell} client by providing a @file{~/.ssh/config} file, which is honored by the OpenSSH client,@command{ssh}, and by other tools such as @command{guix deploy}.") (default-value (home-openssh-configuration)))) ;;; ;;; Ssh-agent. ;;; (define-record-type* home-ssh-agent-configuration make-home-ssh-agent-configuration home-ssh-agent-configuration? (openssh home-ssh-agent-openssh ;file-like (default openssh)) (socket-directory home-ssh-agent-socket-directory ;string (default #~(string-append %user-runtime-dir "/ssh-agent"))) (extra-options home-ssh-agent-extra-options ;list of string (default '()))) (define (home-ssh-agent-services config) "Return a for an ssh-agent with CONFIG." (match-record config (openssh socket-directory extra-options) (let* ((ssh-agent (file-append openssh "/bin/ssh-agent")) (socket-file #~(string-append #$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.")))